Science.gov

Sample records for reduction gears

  1. Final reduction gear apparatus

    SciTech Connect

    Yasui, Y.; Hori, H.

    1987-04-21

    A final reduction gear apparatus is described comprising: a differential carrier which houses a gear assembly; an oil seal attached to a side gear shaft opening in the differential carrier, the oil seal having a main lip which may contact a periphery of a side gear shaft; and a guide member located outside of the oil seal at the side gear shaft opening, the guide member being formed as a member separate from the oil seal, the guide member having a slightly larger inner diameter than that of the main lip of the oil seal, and having guide surface concentric to the main lip, wherein 1/2 of the difference between the inner diameter of the guide member and the inner diameter of the main lip of the oil seal is within the limit of the elastic deformability of the main lip.

  2. Functioning of reduction gears on airplane engines

    NASA Technical Reports Server (NTRS)

    Matteucci, Raffaelli

    1926-01-01

    In undertaking to analyze the functioning conditions of a reduction gear on an aviation engine, we will consider an ordinary twelve-cylinder V-engine. The reduction gear employed consists either of a pair of spur gears, one of which is integral with the engine shaft and the other with the propeller shaft, or of a planetary system of gears.

  3. Engine starter with a planetary reduction gear

    SciTech Connect

    Yabunaka, K.

    1987-06-09

    This patent describes an engine starter having a motor and a planetary reduction gear comprising: a rotor having a rotor shaft; an output shaft drivingly connected to the rotor shaft through the planetary reducing gear; a yoke having a cylindrical portion surrounding the stator and a support portion rotatably supporting the output shaft; a sun gear located on an outer surface of the rotor shaft; a ring gear formed on an inner surface of the yoke; and the yoke, support portion, and the ring gear comprise one-piece.

  4. Optimal design of compact spur gear reductions

    NASA Technical Reports Server (NTRS)

    Savage, M.; Lattime, S. B.; Kimmel, J. A.; Coe, H. H.

    1992-01-01

    The optimal design of compact spur gear reductions includes the selection of bearing and shaft proportions in addition to gear mesh parameters. Designs for single mesh spur gear reductions are based on optimization of system life, system volume, and system weight including gears, support shafts, and the four bearings. The overall optimization allows component properties to interact, yielding the best composite design. A modified feasible directions search algorithm directs the optimization through a continuous design space. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for optimization. After finding the continuous optimum, the designer can analyze near optimal designs for comparison and selection. Design examples show the influence of the bearings on the optimal configurations.

  5. 53. REAR OF MOTOR AND REDUCTION GEAR NO. 2: View ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    53. REAR OF MOTOR AND REDUCTION GEAR NO. 2: View towards northwest showing rear of Motor and Reduction Gear No. 2, installed in 1926. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  6. 55. VIEW TO NORTHEAST OF MOTOR AND REDUCTION GEAR NO. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    55. VIEW TO NORTHEAST OF MOTOR AND REDUCTION GEAR NO. 1: View towards the northeast of Motor and Reduction Gear No. 1, installed in 1957. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  7. 30 CFR 75.1404 - Automatic brakes; speed reduction gear.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Automatic brakes; speed reduction gear. 75.1404... Automatic brakes; speed reduction gear. Each locomotive and haulage car used in an underground coal mine... brakes, locomotives and haulage cars shall be subject to speed reduction gear, or other similar...

  8. 30 CFR 75.1404 - Automatic brakes; speed reduction gear.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic brakes; speed reduction gear. 75.1404... Automatic brakes; speed reduction gear. Each locomotive and haulage car used in an underground coal mine... brakes, locomotives and haulage cars shall be subject to speed reduction gear, or other similar...

  9. 30 CFR 75.1404 - Automatic brakes; speed reduction gear.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Automatic brakes; speed reduction gear. 75.1404... Automatic brakes; speed reduction gear. Each locomotive and haulage car used in an underground coal mine... brakes, locomotives and haulage cars shall be subject to speed reduction gear, or other similar...

  10. Optimal Design of Compact Spur Gear Reductions

    DTIC Science & Technology

    1992-09-01

    stress, psi Lundberg and Palmgren (1952) developed a theory for the life and pressure angle, deg capacity of ball and roller bearings . This life model is... bearings (Lundberg and Paimgren, 1952). Lundberg and Palmgren determined that the scatter in the life of a bearing can be modeled with a two-parameter...optimal design of compact spur gear reductions includes the Vf unit gradient in the feasible direction selection of bearing and shaft proportions in

  11. 17. View of disassembled reduction gear parts including bull and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. View of disassembled reduction gear parts including bull and intermediate gears and pedestal bearing. - Hacienda Azucarera La Esperanza, Steam Engine & Mill, 2.65 Mi. N of PR Rt. 2 Bridge over Manati River, Manati, Manati Municipio, PR

  12. 17. Detail view of coupling shaft connection between reduction gear ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Detail view of coupling shaft connection between reduction gear and cane mill drive gears - Hacienda Azucarera la Igualdad, Sugar Mill Ruins & Steam Engine, PR Route 332, Guanica, Guanica Municipio, PR

  13. 4. END VIEW OF HOIST, SHOWING REDUCTION GEARS AND BED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. END VIEW OF HOIST, SHOWING REDUCTION GEARS AND BED FOR (MISSING) CLUTCH/DRIVE GEAR UNIT, LOOKING SOUTHEAST - Buffalo Coal Mine, Vulcan Cable Hoist, Wishbone Hill, Southeast end, near Moose Creek, Sutton, Matanuska-Susitna Borough, AK

  14. 3. SIDE VIEW OF HOIST, SHOWING REDUCTION GEARS AND BED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. SIDE VIEW OF HOIST, SHOWING REDUCTION GEARS AND BED FOR (MISSING) CLUTCH/DRIVE GEAR UNIT, LOOKING SOUTH - Buffalo Coal Mine, Vulcan Cable Hoist, Wishbone Hill, Southeast end, near Moose Creek, Sutton, Matanuska-Susitna Borough, AK

  15. Order (n) DISCOS for multibody systems with gear reduction

    NASA Technical Reports Server (NTRS)

    Chun, Hon M.; Turner, James D.; Frisch, Harold P.

    1990-01-01

    Recent developments in O(n) algorithms (where n is the number of bodies in the system) and parallel processing have drastically reduced the computer time needed to simulate systems involving many bodies. This paper presents a gear-reduction model for the O(n) version of DISCOS, a standard software package for simulation and analysis of flexible multibody systems. The gear-reduction model allows the accurate modeling of harmonic drives, which are commonly used in robot joints. The formulation has been implemented and validated with known results. The gear model can also be used for gear-train, rack-and-pinion, and screw joints.

  16. 5. OBLIQUE VIEW OF HOIST, SHOWING REDUCTION GEARS AND BED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. OBLIQUE VIEW OF HOIST, SHOWING REDUCTION GEARS AND BED FOR (MISSING) CLUTCH/DRIVE GEAR UNIT, LOOKING EAST (McNALLY DRYER AND COVER SHOWN IN EXTREME UPPER RIGHT BACKGROUND) - Buffalo Coal Mine, Vulcan Cable Hoist, Wishbone Hill, Southeast end, near Moose Creek, Sutton, Matanuska-Susitna Borough, AK

  17. Life and reliability modeling of bevel gear reductions

    NASA Technical Reports Server (NTRS)

    Savage, M.; Brikmanis, C. K.; Lewicki, D. G.; Coy, J. J.

    1985-01-01

    A reliability model is presented for bevel gear reductions with either a single input pinion or dual input pinions of equal size. The dual pinions may or may not have the same power applied for the analysis. The gears may be straddle mounted or supported in a bearing quill. The reliability model is based on the Weibull distribution. The reduction's basic dynamic capacity is defined as the output torque which may be applied for one million output rotations of the bevel gear with a 90 percent probability of reduction survival.

  18. Potential for Landing Gear Noise Reduction on Advanced Aircraft Configurations

    NASA Technical Reports Server (NTRS)

    Thomas, Russell H.; Nickol, Craig L.; Burley, Casey L.; Guo, Yueping

    2016-01-01

    The potential of significantly reducing aircraft landing gear noise is explored for aircraft configurations with engines installed above the wings or the fuselage. An innovative concept is studied that does not alter the main gear assembly itself but does shorten the main strut and integrates the gear in pods whose interior surfaces are treated with acoustic liner. The concept is meant to achieve maximum noise reduction so that main landing gears can be eliminated as a major source of airframe noise. By applying this concept to an aircraft configuration with 2025 entry-into-service technology levels, it is shown that compared to noise levels of current technology, the main gear noise can be reduced by 10 EPNL dB, bringing the main gear noise close to a floor established by other components such as the nose gear. The assessment of the noise reduction potential accounts for design features for the advanced aircraft configuration and includes the effects of local flow velocity in and around the pods, gear noise reflection from the airframe, and reflection and attenuation from acoustic liner treatment on pod surfaces and doors. A technical roadmap for maturing this concept is discussed, and the possible drag increase at cruise due to the addition of the pods is identified as a challenge, which needs to be quantified and minimized possibly with the combination of detailed design and application of drag reduction technologies.

  19. 9. DETAIL VIEW OF REPLACEMENT REDUCTION GEAR FOR TRASHRAKE HOIST, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. DETAIL VIEW OF REPLACEMENT REDUCTION GEAR FOR TRASH-RAKE HOIST, ORIGINAL CONTROLLERS, LOOKING WEST - Cabot Station Electric Generating Plant, Gantry Crane, Montague City Road, Turners Falls vicinity, Montague, Franklin County, MA

  20. SECONDARY GENERAL MOTORS DIESEL ENGINE WITH CONNECTION TO REDUCTION GEAR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SECONDARY GENERAL MOTORS DIESEL ENGINE WITH CONNECTION TO REDUCTION GEAR BELT DRIVE SYSTEM, LOOKING SOUTH. - Mad River Glen, Single Chair Ski Lift, 62 Mad River Glen Resort Road, Fayston, Washington County, VT

  1. 7. VIEW OF REDUCTION GEARS. TRUNNION SUPPORT GIRDERS, SIDES OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW OF REDUCTION GEARS. TRUNNION SUPPORT GIRDERS, SIDES OF COUNTERWEIGHTS, WITH LOWER BUFFERS, LOOKING WEST FROM WEST CANAL PIER. - East Division Street Bridge, Spanning North Branch Canal at West Division Street, Chicago, Cook County, IL

  2. 17. VIEW SOUTHEAST, REDUCTION GEARING AND MOTOR (WITH SOLENOID BRAKE) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. VIEW SOUTHEAST, REDUCTION GEARING AND MOTOR (WITH SOLENOID BRAKE) FOR END LOCKS; VERTICAL SHAFT IN CENTER FOR MANUAL OPERATION - Grand Street Bridge, Spanning Pequonnock River at Grand Street, Bridgeport, Fairfield County, CT

  3. Prediction of Landing Gear Noise Reduction and Comparison to Measurements

    NASA Technical Reports Server (NTRS)

    Lopes, Leonard V.

    2010-01-01

    Noise continues to be an ongoing problem for existing aircraft in flight and is projected to be a concern for next generation designs. During landing, when the engines are operating at reduced power, the noise from the airframe, of which landing gear noise is an important part, is equal to the engine noise. There are several methods of predicting landing gear noise, but none have been applied to predict the change in noise due to a change in landing gear design. The current effort uses the Landing Gear Model and Acoustic Prediction (LGMAP) code, developed at The Pennsylvania State University to predict the noise from landing gear. These predictions include the influence of noise reduction concepts on the landing gear noise. LGMAP is compared to wind tunnel experiments of a 6.3%-scale Boeing 777 main gear performed in the Quiet Flow Facility (QFF) at NASA Langley. The geometries tested in the QFF include the landing gear with and without a toboggan fairing and the door. It is shown that LGMAP is able to predict the noise directives and spectra from the model-scale test for the baseline configuration as accurately as current gear prediction methods. However, LGMAP is also able to predict the difference in noise caused by the toboggan fairing and by removing the landing gear door. LGMAP is also compared to far-field ground-based flush-mounted microphone measurements from the 2005 Quiet Technology Demonstrator 2 (QTD 2) flight test. These comparisons include a Boeing 777-300ER with and without a toboggan fairing that demonstrate that LGMAP can be applied to full-scale flyover measurements. LGMAP predictions of the noise generated by the nose gear on the main gear measurements are also shown.

  4. The effects of gear reduction on robot dynamics

    NASA Technical Reports Server (NTRS)

    Chen, J.

    1989-01-01

    The effect of the joint drive system with gear reduction for a generic two-link system is studied. It is done by comparing the kinetic energy of such a system with that of a direct drive two-link system. The only difference are two terms involving the inertia of the motor rotor and gear ratio. Modifications of the equations of motion from a direct drive system are then developed and generalized to various cases encountered in robot manipulators.

  5. Design Optimization of Marine Reduction Gears.

    DTIC Science & Technology

    1983-09-01

    Approved by: A t/ 6 𔃼 -A-,i Thesis Advisor Second Reader Chairman,De rtment or Mecanica Engineering I De&n of Science and Engineering 3...unconstrained problems. 1. Direct Methods Direct methods are popular constrained optimization algorithms. One well known direct method is the method of...various popular tooth forms and Appendix A contains a descriptive figure of gear tooth design variables. However, the following equations are a good

  6. A Landing Gear Noise Reduction Study Based on Computational Simulations

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.; Lockard, David P.

    2006-01-01

    Landing gear is one of the more prominent airframe noise sources. Techniques that diminish gear noise and suppress its radiation to the ground are highly desirable. Using a hybrid computational approach, this paper investigates the noise reduction potential of devices added to a simplified main landing gear model without small scale geometric details. The Ffowcs Williams and Hawkings equation is used to predict the noise at far-field observer locations from surface pressure data provided by unsteady CFD calculations. Because of the simplified nature of the model, most of the flow unsteadiness is restricted to low frequencies. The wheels, gear boxes, and oleo appear to be the primary sources of unsteadiness at these frequencies. The addition of fairings around the gear boxes and wheels, and the attachment of a splitter plate on the downstream side of the oleo significantly reduces the noise over a wide range of frequencies, but a dramatic increase in noise is observed at one frequency. The increased flow velocities, a consequence of the more streamlined bodies, appear to generate extra unsteadiness around other parts giving rise to the additional noise. Nonetheless, the calculations demonstrate the capability of the devices to improve overall landing gear noise.

  7. Aeroacoustic Evaluation of Flap and Landing Gear Noise Reduction Concepts

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.; Humphreys, William M., Jr.; Lockard, David P.; Ravetta, Patricio A.

    2014-01-01

    Aeroacoustic measurements for a semi-span, 18% scale, high-fidelity Gulfstream aircraft model are presented. The model was used as a test bed to conduct detailed studies of flap and main landing gear noise sources and to determine the effectiveness of numerous noise mitigation concepts. Using a traversing microphone array in the flyover direction, an extensive set of acoustic data was obtained in the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel with the facility in the acoustically treated open-wall (jet) mode. Most of the information was acquired with the model in a landing configuration with the flap deflected 39 deg and the main landing gear alternately installed and removed. Data were obtained at Mach numbers of 0.16, 0.20, and 0.24 over directivity angles between 56 deg and 116 deg, with 90 deg representing the overhead direction. Measured acoustic spectra showed that several of the tested flap noise reduction concepts decrease the sound pressure levels by 2 - 4 dB over the entire frequency range at all directivity angles. Slightly lower levels of noise reduction from the main landing gear were obtained through the simultaneous application of various gear devices. Measured aerodynamic forces indicated that the tested gear/flap noise abatement technologies have a negligible impact on the aerodynamic performance of the aircraft model.

  8. 30 CFR 75.1404 - Automatic brakes; speed reduction gear.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Hoisting and Mantrips § 75.1404 Automatic brakes; speed reduction gear. Each locomotive and haulage car used in an underground coal mine shall be equipped with automatic brakes, where space permits. Where space does not permit...

  9. 30 CFR 75.1404 - Automatic brakes; speed reduction gear.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Hoisting and Mantrips § 75.1404 Automatic brakes; speed reduction gear. Each locomotive and haulage car used in an underground coal mine shall be equipped with automatic brakes, where space permits. Where space does not permit...

  10. Gearing

    NASA Technical Reports Server (NTRS)

    Coy, J. J.; Townsend, D. P.; Zaretsky, E. V.

    1985-01-01

    Gearing technology in its modern form has a history of only 100 years. However, the earliest form of gearing can probably be traced back to fourth century B.C. Greece. Current gear practice and recent advances in the technology are drawn together. The history of gearing is reviewed briefly in the Introduction. Subsequent sections describe types of gearing and their geometry, processing, and manufacture. Both conventional and more recent methods of determining gear stress and deflections are considered. The subjects of life prediction and lubrication are additions to the literature. New and more complete methods of power loss predictions as well as an optimum design of spur gear meshes are described. Conventional and new types of power transmission systems are presented.

  11. Landing Gear Door Liners for Airframe Noise Reduction

    NASA Technical Reports Server (NTRS)

    Jones, Michael G. (Inventor); Howerton, Brian M. (Inventor); Van De Ven, Thomas (Inventor)

    2014-01-01

    A landing gear door for retractable landing gear of aircraft includes an acoustic liner. The acoustic liner includes one or more internal cavities or chambers having one or more openings that inhibit the generation of sound at the surface and/or absorb sound generated during operation of the aircraft. The landing gear door may include a plurality of internal chambers having different geometries to thereby absorb broadband noise.

  12. Gearing.

    DTIC Science & Technology

    1985-12-01

    earliest written descriptions of gears are said to (ref. 3), appear in the sketchbooks of Leonardo da Vinci , . . - have been made by Aristotle in the fourth... Vinci , Leonardo (L. Reti, transl.): The Madrid Codices. American Gear Manufacturers Association, Aug. 1966. McGraw-Hill Book Co., Inc., 1974. 33... Leonardo da Vinci’s manuscripts, lost in the "’ ppassage attributed by some to Aristotle, in "Mechanical National Library in Madrid since 1830., were

  13. Quiet Clean Short-haul Experimental Engine (QCSEE) main reduction gears detailed design report

    NASA Technical Reports Server (NTRS)

    Defeo, A.; Kulina, M.

    1977-01-01

    Lightweight turbine engines with geared slower speed fans are considered. The design of two similar but different gear ratio, minimum weight, epicyclic star configuration main reduction gears for the under the wing (UTW) and over the wing (OTW) engines is discussed. The UTW engine reduction gear has a ratio of 2.465:1 and a 100% power design rating of 9885 kW (13,256 hp) at 3143 rpm fan speed. The OTW engine reduction gear has a ratio of 2.062:1 and a 100% power design rating of 12813 kW (17183 hp) at 3861 rpm fan speed. Details of configuration, stresses, deflections, and lubrication are presented.

  14. Actively Controlled Landing Gear for Aircraft Vibration Reduction

    NASA Technical Reports Server (NTRS)

    Horta, Lucas G.; Daugherty, Robert H.; Martinson, Veloria J.

    1999-01-01

    Concepts for long-range air travel are characterized by airframe designs with long, slender, relatively flexible fuselages. One aspect often overlooked is ground induced vibration of these aircraft. This paper presents an analytical and experimental study of reducing ground-induced aircraft vibration loads using actively controlled landing gears. A facility has been developed to test various active landing gear control concepts and their performance. The facility uses a NAVY A6-intruder landing gear fitted with an auxiliary hydraulic supply electronically controlled by servo valves. An analytical model of the gear is presented including modifications to actuate the gear externally and test data is used to validate the model. The control design is described and closed-loop test and analysis comparisons are presented.

  15. Quiet Clean Short-haul Experimental Engine (QCSEE) main reduction gears test program

    NASA Technical Reports Server (NTRS)

    Misel, O. W.

    1977-01-01

    Sets of under the wing (UTW) engine reduction gears and sets of over the wing (OTW) engine reduction gears were fabricated for rig testing and subsequent installation in engines. The UTW engine reduction gears which have a ratio of 2.465:1 and a design rating of 9712 kW at 3157 rpm fan speed were operated at up to 105% speed at 60% torque and 100% speed at 125% torque. The OTW engine reduction gears which have a ratio of 2.062:1 and a design rating of 12,615 kW at 3861 rpm fan speed were operated at up to 95% speed at 50% torque and 80% speed at 109% torque. Satisfactory operation was demonstrated at powers up to 12,172 kW, mechanical efficiency up to 99.1% UTW, and a maximum gear pitch line velocity of 112 m/s (22,300 fpm) with a corresponding star gear spherical roller bearing DN of 850,00 OTW. Oil and star gear bearing temperatures, oil churning, heat rejection, and vibratory characteristics were acceptable for engine installation.

  16. The reduction of takeoff ground roll by the application of a nose gear jump strut

    NASA Technical Reports Server (NTRS)

    Eppel, Joseph C.; Maisel, Martin D.; Mcclain, J. Greer; Luce, W.

    1994-01-01

    A series of flight tests were conducted to evaluate the reduction of takeoff ground roll distance obtainable from a rapid extension of the nose gear strut. The NASA Quiet Short-haul Research Aircraft (QSRA) used for this investigation is a transport-size short take off and landing (STOL) research vehicle with a slightly swept wing that employs the upper surface blowing (USB) concept to attain the high lift levels required for its low-speed, short-field performance. Minor modifications to the conventional nose gear assembly and the addition of a high-pressure pneumatic system and a control system provided the extendable nose gear, or jump strut, capability. The limited flight test program explored the effects of thrust-to-weight ratio, wing loading, storage tank initial pressure, and control valve open time duration on the ground roll distance. The data show that a reduction of takeoff ground roll on the order of 10 percent was achieved with the use of the jump strut, as predicted. Takeoff performance with the jump strut was also found to be essentially independent of the pneumatic supply pressure and was only slightly affected by control valve open time within the range of the parameters examined.

  17. An Interactive Computer Program for the Preliminary Design and Analysis of Marine Reduction Gears.

    DTIC Science & Technology

    1982-03-01

    axis and simple epicyclic reduction gears. It is caD -beo 71J? 1473 too-roos OP, I Nov6$15i ORLE TVNICLASST IFl um u ewd S/01 0102-014- 6601 66CUOIIY...CONCLUSIONS AND RECOMBENDATICNS Computer aided design ( CAD ) is an important and useful tool ’or engineers. As computer technology continues to expand, CAD ...N e E-H4o m H4 4 E-4. Cad 0 0 = *uuu I! 2I4 E-4 0H o( - =C = e4r (n ) T-N f co~~~2 aU OD 0 %D00mmm0 Aw 0 94 71z 00 0 p nc nc 0 C; 4 H 0 2q 0I go 04

  18. Offset Compound Gear Drive

    NASA Technical Reports Server (NTRS)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2010-01-01

    The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

  19. Gear bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2003-01-01

    A gear bearing having a first gear and a second gear, each having a plurality of teeth. Each gear operates on two non-parallel surfaces of the opposing gear teeth to perform both gear and bearing functions simultaneously. The gears are moving at substantially the same speed at their contact points. The gears may be roller gear bearings or phase-shifted gear bearings, and may be arranged in a planet/sun system or used as a transmission.

  20. Passive reduction of gear mesh vibration using a periodic drive shaft

    NASA Astrophysics Data System (ADS)

    Richards, D.; Pines, D. J.

    2003-07-01

    In this paper, a passive approach to reduce transmitted vibration generated by gear mesh contact dynamics is presented. The approach utilizes the property of periodic structural components that creates stop band and pass band regions in the frequency spectra. The stop band regions can be tailored to correspond to regions of the frequency spectra that contain harmonics and sub-harmonics of the gear mesh frequency, attenuating the response in those regions. A periodic structural component is comprised of a repeating array of cells, which are themselves an assembly of elements. The elements may have differing material properties as well as geometric variations. For the purpose of this research, only geometric variations are considered and each cell is assumed to be identical. A periodic shaft is designed and machined in order to reduce transmitted vibration of a pair of spur gears. Analytical and experimental results indicate that transmitted vibrations from gear mesh contact to the bearing supports are reduced at a variety of operational speeds under static torque preload.

  1. Planetary gear train ring gear and support structure investigation

    NASA Astrophysics Data System (ADS)

    Valco, Mark J.

    1992-01-01

    Most helicopter transmissions utilize a planetary gear train as the final speed reduction stage. Due to weight constraints these transmissions have high power-to-weight ratios and relatively flexible structures. This investigation addresses the analysis of planetary gear trains with the ring gear mounted on a flexible support structure. The approach utilizes recent advances in automated contact methods for nonlinear finite element analysis. Rather than using a line of action spring to model gear pair mesh stiffness, finite element models of complete gears are developed, and the elastic gear members are engaged and rolled through mesh. The procedure includes detailed gear tooth geometry with profile modifications. A nonlinear approach is required due to large displacements associated with gear rotation and nonlinear boundary conditions associated with the gear tooth surface contact. The updated Lagrangian formulation and the MARC K-4.1 automated contact features are applied in the analysis. The ring gear support structure is modeled by an elastic foundation linking the ring gear to a rigid support. Calculation of gear pair deflections, stresses, transmission error, and mesh stiffness through the gear meshing cycle are demonstrated for external and internal spur gear pairs and a planetary gear train. Issues relating to the accuracy of the nonlinear finite element contact method, gear mesh stiffness, transmission error, and the planetary gear train elastic support structure are discussed.

  2. Gear optimization

    NASA Technical Reports Server (NTRS)

    Vanderplaats, G. N.; Chen, Xiang; Zhang, Ning-Tian

    1988-01-01

    The use of formal numerical optimization methods for the design of gears is investigated. To achieve this, computer codes were developed for the analysis of spur gears and spiral bevel gears. These codes calculate the life, dynamic load, bending strength, surface durability, gear weight and size, and various geometric parameters. It is necessary to calculate all such important responses because they all represent competing requirements in the design process. The codes developed here were written in subroutine form and coupled to the COPES/ADS general purpose optimization program. This code allows the user to define the optimization problem at the time of program execution. Typical design variables include face width, number of teeth and diametral pitch. The user is free to choose any calculated response as the design objective to minimize or maximize and may impose lower and upper bounds on any calculated responses. Typical examples include life maximization with limits on dynamic load, stress, weight, etc. or minimization of weight subject to limits on life, dynamic load, etc. The research codes were written in modular form for easy expansion and so that they could be combined to create a multiple reduction optimization capability in future.

  3. Transmission with two parallel driving shafts bearing two driving gears each meshed with same driven gear on parallel driven shaft

    SciTech Connect

    Akashi, T.; Ito, H.; Yamada, S.

    1986-06-17

    A transmission mechanism for a vehicle is described for receiving input of rotational power from a power supply member which rotates in a particular rotational direction and for outputting rotational power to a power receiving member which includes: an input member connected to the power supply member and which is rotatably mounted and receives supplying of the rotational power from the power supply member; a first driving gear wheel shaft; a second driving gear wheel shaft mounted generally parallel to the first driving gear wheel shaft; a driven gear wheel shaft mounted generally parallel to the first and second driving gear wheel shafts, the driven gear wheel shaft being rotationally connected to the power receiving member; a first driven gear wheel fixedly mounted on the driven gear wheel shaft; a first driving gear wheel which is rotatably mounted on the first driving gear wheel shaft and is constant mesh with the driven gear wheel, the first driving and driven gear wheels providing a first reduction gear ratio from the first driving gear wheel shaft to the driven gear wheel shaft; a second driven gear wheel fixedly mounted on the driven gear wheel shaft; a second driving gear wheel which is rotatably mounted on the second driving gear wheel shaft and is in constant mesh with the first driven gear wheel, the second driving and the first driven gear wheels providing a second reduction gear ratio smaller than the first reduction gear ratio from the second driving gear wheel shaft to the driven gear wheel shaft; a third driving gear wheel which is rotatably mounted on the first driving gear wheel shaft and is in constant mesh with the second driven gear wheel, the third driving and the second driven gear wheels providing a third reduction gear ratio smaller than the second reduction gear ratio from the first driving gear wheel shaft to the driven gear wheel shaft.

  4. Hybrid Gear

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  5. Automated Inspection And Precise Grinding Of Gears

    NASA Technical Reports Server (NTRS)

    Frint, Harold; Glasow, Warren

    1995-01-01

    Method of precise grinding of spiral bevel gears involves automated inspection of gear-tooth surfaces followed by adjustments of machine-tool settings to minimize differences between actual and nominal surfaces. Similar to method described in "Computerized Inspection of Gear-Tooth Surfaces" (LEW-15736). Yields gears of higher quality, with significant reduction in manufacturing and inspection time.

  6. Driving gear for front and rear wheels of automobile

    SciTech Connect

    Ashikawa, N.; Sakuma, S.

    1986-10-21

    A driving gear is described for front and rear wheels of an automobile, comprising an engine with a crank shaft disposed in a direction of width of a body of the automobile, a transmission supported on an engine case at one side axially of the crank shaft, and a clutch provided between the engine and the transmission. The driving gear includes a first differential gear of a planetary gear type coupled to the transmission via a reduction gear, a second differential gear of a bevel gear type transmission an output of the first differential gear to left and right front wheels of the automobile, and a third differential gear transmitting an output of the first differential gear to left and right rear wheels of the automobile. The first differential gear is disposed adjacent to the reduction gear and comprises a sun gear, a ring gear and planet gears engaging with the sun and ring gears. The planet gears are pivoted directly on and driven by the reduction gear; the first and second differential gears are provided on opposite sides of a plane perpendicular to the crankshaft and including the clutch. The first and second differential gears also lie along a common axis parallel to the crank shaft. The sun gear and the ring gear are coupled individually to the front and rear wheels respectively.

  7. Differential gearing

    SciTech Connect

    Tamiya, S.

    1986-07-29

    A differential for motor vehicles is described and the like comprising, an input drive shaft, a pair of coaxially spaced drive gears simultaneously driven by the input shaft in a same direction at a same speed of rotation about a common axis of rotation, a driven gear driven peripherally by the pair of drive gears for transmission of power from the input drive shaft, two coaxial opposed bevel sun gears having an axis of rotation concentric with an axis of rotation of the driven gear, two planetary gears disposed between the sun gears for differential driving thereof during turns of the vehicle to the right and to the left of each meshing with the sun gears for driving the suns gears. Each planetary gear has a separate axis of rotation carried by the driven gear disposed therein radially and symmetrically relative to the axis of rotation of the sun gears, and each sun gear having a respective power output shaft connected thereto for rotation therewith.

  8. The Effect of Reduction Gearing on Propeller-body Interference as Shown by Full-Scale Wind-Tunnel Tests

    NASA Technical Reports Server (NTRS)

    Weick, Fred E

    1931-01-01

    This report presents the results of full-scale tests made on a 10-foot 5-inch propeller on a geared J-5 engine and also on a similar 8-foot 11-inch propeller on a direct-drive J-5 engine. Each propeller was tested at two different pitch settings, and with a large and a small fuselage. The investigation was made in such a manner that the propeller-body interference factors were isolated, and it was found that, considering this interference only, the geared propellers had an appreciable advantage in propulsive efficiency, partially due to the larger diameter of the propellers with respect to the bodies, and partially because the geared propellers were located farther ahead of the engines and bodies.

  9. Gear Tooth Scoring Investigation

    DTIC Science & Technology

    1975-07-01

    C. Elastohydrodynamic Lubrication 20 D. Boundary Lubrication 23 E. Lubrication-Limited Gear Performance 24 F. Impact of Gear Mechanics 25...III. SPUR GEAR MECHANICS 28 A. Spur Gear Kinematics 28 B. Spur Gear Statics 31 C. Spur Gear Dynamics 38 IV. HELICAL GEAR MECHANICS 46 A...Helical Gear Kinematics 46 B. Helical Gear Statics 48 C. Helical Gear Dynamics 50 V. SPIRAL BEVEL GEAR MECHANICS 53 A. Spiral Bevel Gear

  10. Proposal of an Axial Gap Magnetic Gear

    NASA Astrophysics Data System (ADS)

    Hirata, Katsuhiro; Yamamoto, Masafumi; Muramatsu, Masari

    Magnetic gears have some benefits such as low noise, low vibration, and they are maintenance free as opposed to mechanical gears. In the view of these advantages, some high-performance magnetic gears have been proposed; however, these gears have a complex structure because they require several magnets. In this paper, we propose a new magnetic gear with a high reduction ratio comprising only two magnets. From the result of 3D-FE analysis, it was found that our model generated large transmitted torque and less cogging torque despite its thin compact size. This result shows the possibility of the application of the proposed gear in various industries.

  11. 50 CFR 660.506 - Gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear restrictions. 660.506 Section 660.506 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 660.506 Gear restrictions. The only fishing gear authorized for use in the reduction fishery...

  12. 50 CFR 660.506 - Gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear restrictions. 660.506 Section 660.506 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 660.506 Gear restrictions. The only fishing gear authorized for use in the reduction fishery...

  13. 9. VIEW SOUTHWEST OF PRIMARY REDUCING GEARS; NOTE BRAKE WHEEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. VIEW SOUTHWEST OF PRIMARY REDUCING GEARS; NOTE BRAKE WHEEL AND PADS AT RIGHT CENTER BEHIND PRIMARY GEAR; MITER GEAR AT CENTER IS PART OF MECHANISM FOR MANUAL OPERATION OF BRIDGE; FLANGE FOR COUPLING THE NORTH AND SOUTH REDUCTION GEAR TRAINS IS AT CENTER OF PHOTOGRAPH BEHIND SOUTH PRIMARY REDUCTION GEAR - East Washington Avenue Bridge, Spanning Pequonnock River at East Washington Avenue, Bridgeport, Fairfield County, CT

  14. Gear Performance Improved by Coating

    NASA Technical Reports Server (NTRS)

    Krantz, Timothy L.

    2004-01-01

    run until either surface fatigue occurred or 300 million stress cycles were completed. Tests were run using either a pair of uncoated gears or a pair of coated gears (coated gears mated with uncoated gears were not evaluated). The fatigue test results, shown on Weibull coordinates in the graph, demonstrate that the coating provided substantially longer fatigue lives even though some of the coated gears endured larger stresses. The increase in fatigue life was a factor of about 5 and the statistical confidence for the improvement is high (greater than 99 percent). Examination of the tested gears revealed substantial reductions of total wear for coated gears in comparison to uncoated gears. The coated gear surface topography changed with running, with localized areas of the tooth surface becoming smoother with running. Theories explaining how coatings can extend gear fatigue lives are research topics for coating, tribology, and fatigue specialists. This work was done as a partnership between NASA, the U.S. Army Research Laboratory, United Technologies Research Corporation, and Sikorsky Aircraft.

  15. Differential gear

    SciTech Connect

    Shibuya, K.; Hamada, T.; Masuda, K.; Shimada, K.

    1989-05-02

    A differential gear for permitting a difference in rotational speed between two output shafts is described, the differential gear including an input shaft and two output shafts. The improvement consists of means for limiting the difference in rotational speed between the two output shafts in response to the rotational speed of the input shaft, the rotational speed limiting means comprising a differential casing coupled to the input shaft and adapted to be rotated by the input shaft, a differential pinion shaft radially extending within the differential casing and rotatably mounted at its opposite ends in the differential casing. A plurality of differential pinion gears rotatably mounted on the differential pinion shaft is also included, and also a pair of side gears having a rotational axis common to that of the differential casing, wherein the side gears mesh with the differential pinion gears and the two output shafts are fixed to the side gears, the means for limiting the difference in rotational speed between the two output shafts comprising a weight means radially movable in the differential casing, the weight means limiting the difference in rotational speed between the two output shafts in response to the centrifugal force applied to the weight means, the weight means being slidably mounted on the differential pinion shaft and being biased radially inwardly.

  16. Development in Geared Turbofan Aeroengine

    NASA Astrophysics Data System (ADS)

    Mohd Tobi, A. L.; Ismail, A. E.

    2016-05-01

    This paper looks into the implementation of epicyclic gear system to the aeroengine in order to increase the efficiency of the engine. The improvement made is in the direction of improving fuel consumption, reduction in pollutant gasses and perceived noise. Introduction of epicyclic gear system is capable to achieve bypass ratio of up to 15:1 with the benefits of weight and noise reduction. Radical new aircraft designs and engine installation are being studied to overcome some of the challenges associated with the future geared turbofan and open-rotor engine.

  17. Reliability model for planetary gear

    NASA Technical Reports Server (NTRS)

    Savage, M.; Paridon, C. A.; Coy, J. J.

    1982-01-01

    A reliability model is presented for planetary gear trains in which the ring gear is fixed, the Sun gear is the input, and the planet arm is the output. The input and output shafts are coaxial and the input and output torques are assumed to be coaxial with these shafts. Thrust and side loading are neglected. This type of gear train is commonly used in main rotor transmissions for helicopters and in other applications which require high reductions in speed. The reliability model is based on the Weibull distribution of the individual reliabilities of the transmission components. The transmission's basic dynamic capacity is defined as the input torque which may be applied for one million input rotations of the Sun gear. Load and life are related by a power law. The load life exponent and basic dynamic capacity are developed as functions of the component capacities.

  18. Geared power transmission technology

    NASA Technical Reports Server (NTRS)

    Coy, J. J.

    1983-01-01

    The historical path of the science and art of gearing is reviewed. The present state of gearing technology is discussed along with examples of some of the NASA-sponsored contributions to gearing technology. Future requirements in gearing are summarized.

  19. 78 FR 68817 - Proposed Information Collection; Comment Request; Northeast Region Gear Identification

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-15

    ... Region Gear Identification AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and.... Abstract This notice is for the extension of Paperwork Reduction Act requirements regarding fishing gear... fishing gear mark the gear with specified information. The gear marking requirements provide vessel...

  20. Transmission gearing arrangement

    SciTech Connect

    Klemen, D.

    1987-08-04

    A gearing arrangement is described for an automotive power transmission comprising: an input shaft and an output shaft; first, second, and third simple planetary gear sets. Each has a sun gear, a ring gear, and a planet gears meshing with the sun and the ring gears and rotatably supported on a planet carrier; means rigidly interconnecting the ring gear of the third gear set and the carrier of the second gear set; means rigidly interconnecting the ring gear of the second gear set and the carrier of the first gear set; means rigidly connecting the output shaft and the carrier of the third gear set; a first intermediate shaft rigidly interconnecting the sun gears of the second and the third gear sets for unitary rotation; a second intermediate shaft rigidly connected to the carrier of the second gear set; a third intermediate shaft continuously connected to the input shaft and to the sun gear of the first gear set; first, second, and third brake means operative to selectively brake rotation of the ring gears of the first, the second, and the third gear sets, respectively; a first rotating clutch selectively operable to connect the input shaft and the first intermediate shaft for unitary rotation; a second rotating clutch selectively operable to connect the input shaft and the second intermediate shaft for unitary rotation; a fourth simple planetary gear set including a sun gear and a ring gear and planet gears meshing with the sun and the ring gears and rotatably supported on a planet carrier; means rigidly connecting the sun gear of the fourth gear set to the third intermediate shaft; means rigidly connecting the ring gear of the fourth gear set to the carrier of the first gear set; and a fourth brake means selectively operable to brake the carrier of the fourth gear set. The nine forward ratios are obtainable while preserving a single transition shifting over the entire nine forward ratios.

  1. A study of polymer quenching on gears

    SciTech Connect

    Zhao, H.; Yi, T.

    1996-12-31

    The quenching oil was widely used as a quenchant for the carburized gear direct hardening. With the progress of the quenching technology, however, the oil quenching of gears has been successfully replaced by the polymer quenching in the production. This paper will investigate the principle and application of gear quenching to replace oil, with aqueous polymer quenchants. During the direct quenching of carburized gear and precision forging gear, cracking and distortion reduction, and maximum and uniformity hardness can be achieved. From the quenching process and economic, advantages and limitations of polymer quenching of gears will be discussed. The data of production indicate that it is suitable for gear hardening to use polymer quenchant. The characteristics of polymer quenching are the improved performance, reduced fire hazards and environmental safety, processing flexibility and lower process costs.

  2. Handbook on Face Gear Drives with a Spur Involute Pinion

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Egelja, A.; Tan, J.; Chen, D. Y.-D.; Heath, G.

    2000-01-01

    The use of face gears in power transmission and drive systems has a significant number of benefits. Face gears allow a variety of new transmission arrangements as well as high reduction ratio capability. This leads to drive system weight reduction and improvements in performance. In this work, basic information about the design and analysis of face gear drives is presented. The work considers face gears in mesh with spur involute pinions for both intersecting axes and offset drives. Tooth geometry, kinematics, generation of face gears with localized bearing contact by cutting and grinding, avoidance of tooth undercutting, avoidance of tooth pointing, tooth contact analysis, and algorithms for the simulation of meshing and contact arc all topics which are discussed. In addition, applications of face gear drives are presented. Included are design uses in aerospace applications such as helicopter transmissions, split-torque face gear arrangements, comparisons of face gears with bevel gears, and general design considerations.

  3. High reduction transaxle for electric vehicle

    SciTech Connect

    Kalns, Ilmars

    1987-01-01

    A drivetrain (12) includes a transaxle assembly (16) for driving ground engaging wheels of a land vehicle powered by an AC motor. The transaxle includes a ratio change section having planetary gear sets (24, 26) and brake assemblies (28, 30). Sun gears (60, 62) of the gear sets are directly and continuously connected to an input drive shaft (38) driven by the motor. A first drive (78a) directly and continuously connects a planetary gear carrier (78) of gear sets (24) with a ring gear (68) of gear set (26). A second drive (80a) directly and continuously connects a planetary gear carrier (80) of gear set (26) with a sun gear (64) of a final speed reduction gear set (34) having a planetary gear carrier directly and continuously connected to a differential (22). Brakes (28, 30) are selectively engageable to respectively ground a ring gear 66 of gear set 24 and ring gear 68 of gear set 26.

  4. Design of aircraft turbine fan drive gear transmission system

    NASA Technical Reports Server (NTRS)

    Dent, E.; Hirsch, R. A.; Peterson, V. W.

    1970-01-01

    The following basic types of gear reduction concepts were studied as being feasible power train systems for a low-bypass-ratio, single-spool, geared turbofan engine for general aircraft use: (1) single-stage external-internal reduction, (2) gears (offset shafting), (3) multiple compound idler gear system (concentric shafting), and (4) star gear planetary system with internal ring gear final output member (concentric shafting-counterrotation). In addition, studies were made of taking the accessories drive power off both the high-speed and low-speed shafting, using either face gears or spiral bevel gears. Both antifriction and sleeve-type bearings were considered for the external-internal and star-planet reduction concepts.

  5. Flex-Gears

    NASA Technical Reports Server (NTRS)

    Tsai, Lung-Wen; Peritt, Jonathan

    1993-01-01

    Flex-Gears are being developed as an alternative to brushes and slip rings to conduct electricity across a rotating joint. Flex-Gears roll in the annulus of sun and ring gears for electrical contact while maintaining their position by using a novel application of involute gears. A single Flex-Gear is predicted to transfer up to 2.8 amps, thereby allowing a six inch diameter device, holding 30 Flex-Gears, to transfer over 80 amps. Semi-rigid Flex-Gears are proposed to decrease Flex-Gear stress and insure proper gear meshing.

  6. Effects of gear crack propagation paths on vibration responses of the perforated gear system

    NASA Astrophysics Data System (ADS)

    Ma, Hui; Pang, Xu; Zeng, Jin; Wang, Qibin; Wen, Bangchun

    2015-10-01

    This paper investigates the dynamic behaviors of a perforated gear system considering effects of the gear crack propagation paths and this study focuses on the effects of a crack propagating through the rim on the time-varying mesh stiffness (TVMS) and vibration responses. Considering the effects of the extended tooth contact, a finite element (FE) model of a gear pair is established based on ANSYS software. TVMS of the perforated gear with crack propagating through tooth and rim are calculated by using the FE model. Furthermore, a lumped mass model is adopted to investigate the vibration responses of the perforated gear system. The results show that there exist three periods related to slots of the gear body in a rotating period of the perforated gear. Gear cracks propagating through tooth and rim both reduce the gear body stiffness and lead to reduction of TVMS besides the crack tooth contact moment, and the TVMS weakening for the former is less than that for the latter. Moreover, the results also show that the gear crack propagating through the rim (CPR) has a greater effect on vibration responses than the gear crack propagating through the tooth (CPT) under the same crack level. Vibration level increases with the increasing crack depth, especially for the gear with CPR.

  7. Gear box assembly

    SciTech Connect

    Harrod, L.R.; Siebern, M.R.

    1989-04-25

    This patent describes a gearbox assembly for a vehicle which includes a driven axle shaft extending transversely of the vehicle having wheels secured thereto: a drive gear concentric with the axle shaft nonrotatably connected to the shaft, the drive gear having an integral hub on each of opposite sides thereof, a pinion gear shiftably mounted above the drive gear having one position engaging the drive gear and shiftable laterally to disengage from the drive gear, a shift lever mounted in a position projecting upwardly from the pinion gear actuatable to shift the pinion gear, an electric motor with output shaft mounted with the output shaft paralleling the axle shaft and having a driving gear mounted thereon, a multiple gear gear train mounted so as to establish a driving connection between the driving gear and the pinion gear, and a transmission housing enclosing the driving gar, gear train, pinion gear and drive gear, the housing including sleeve portions rotatably receiving the hubs of the drive gear and thus rotatably mounting the drive gear and the axle shaft connected to the drive gear.

  8. Planetary gear train

    SciTech Connect

    Hiraiwa, K.

    1988-10-04

    A planetary gear train is described comprising: an input member; an output member; a first planetary gear set including a first sun gear, a first ring gear, and a first pinion carrier rotatably supporting first planet pinions; a secondary planetary gear set including a second sun gear, and second ring gear and a second pinion carrier rotatably supporting second planet pinions; first drive means for connecting the input member with the first ring gear; second drive means for connecting the input member with the first sun gear; third drive means for constantly connecting the first sun gear with the second sun gear and establishing a force transmitting positive drive from the first sun gear to the second sun gear, whereby the first sun gear rotates at a speed different from the second sun gear; first brake means for braking the second sun gear; second brake means for braking the second pinion carrier; fourth drive means for connecting the second ring gear with the output member and providing a first speed ratio therebetween; and fifth drive means for connecting the first pinion carrier with the output member and providing a second speed ratio therebetween, the second speed ratio being different from the first speed ratio.

  9. Modelling of vibration of gear transmissions

    NASA Astrophysics Data System (ADS)

    Zeman, Vladimir; Nemecek, Josef

    The method for mathematical modeling of spatial vibrations of the spur gear transmissions is presented. This method enables a substantial reduction of the number of degrees of freedom with relatively high accuracy in calculating vibration amplitude.

  10. Assessment of worm gearing for helicopter transmissions

    NASA Technical Reports Server (NTRS)

    Chaiko, Lev

    1990-01-01

    A high-efficiency hydrostatic worm gear drive for helicopter transmissions is assessed. The example given is for a large cargo helicopter with three 4000-kW engines and transmission reduction ratio of 110. Also contained are: an efficiency calculation, a description of the test stand for evaluating the feasibility of worm gear hydrostatic mesh, a weight calculation, and a comparison with conventional helicopter transmissions of the same power and transmission reduction ratio.

  11. Antibacklash gears including rack and pinion gears

    SciTech Connect

    Kerkoff, E.F.

    1989-11-14

    This patent describes a meshing gear construction comprising a first gear having a plurality of fixed teeth extending therefrom. The teeth alternatingly separated by a plurality of roots each having a radial centerline, faces on either side of each fixed tooth, each root being a continuation of a pair of faces of two adjacent teeth, a second gear having a plurality of rollers thereon rotatable relative to the second gear. The rollers meshing with the fixed teeth of the first gear. The meshing comprising rolling contact of at least two rollers with one first gear fixed tooth at all instants of motion. Wherein the rollers comprise cylindrical rollers and the faces of the fixed teeth comprise circular arcs in profile and wherein a radial centers of fixed tooth circular arc face lies outside a pitch circle of the first gear and between the circular arc face and the radial centerline of an adjacent root.

  12. Maximum life spur gear design

    NASA Technical Reports Server (NTRS)

    Savage, M.; Mackulin, M. J.; Coe, H. H.; Coy, J. J.

    1991-01-01

    Optimization procedures allow one to design a spur gear reduction for maximum life and other end use criteria. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial guess values. The optimization algorithm is described, and the models for gear life and performance are presented. The algorithm is compact and has been programmed for execution on a desk top computer. Two examples are presented to illustrate the method and its application.

  13. Driving gear interaxle differential assembly for all-wheel-drive vehicles

    SciTech Connect

    Ashikawa, N.; Friedrich, K.; Lanzer, H.

    1986-05-20

    A driving gear is described for all-wheel-drive vehicles, comprising a reduction gear meshed with an output gear in a transmission, a planetary gear type interaxle differential gear arranged concentrically with the reduction gear so as to output the driving force therefrom into front and rear interwheel differential gears in a divided manner, a driving shaft provided through and concentrically with the interaxle differential gear so as to transmit one output therefrom to one of the two interwheel differential gears, and a driving gear member mounted on the driving shaft so that the driving gear member can be rotated relatively thereto, so as to transmit the other output from the interaxle differential gear to the other interwheel differential gear. The interaxle differential gear consists of a planetary carrier mounted rotatably on the driving shaft on the side of the driving gear member so as to form a clearance between the planetary carrier and the driving shaft, a support member mounted rotatably on the driving shaft so as to be opposed to the planetary carrier, and a ring gear, pinions and a sun gear which are provided between the planetary carrier and the support member, a connecting member which joins the ring gear and the driving shaft together being provided between the pinions and the support member. The driving shaft is provided with a spline for joining the connecting member thereto, the driving gear member being provided with a hub formed integrally therewith, extending from the clearance into the interaxle differential gear and having a connecting portion joined to the sun gear. The reduction gear is formed unitarily with the planetary carrier and the support member.

  14. Gear tooth topological modification

    NASA Technical Reports Server (NTRS)

    Kish, Jules G. (Inventor); Isabelle, Charles (Inventor)

    1994-01-01

    The topology of parallel axis gears, such as spur and helical gears is modified to produce quieter and more smoothly operating gear sets with more uniform load distribution. A finite element analysis of the gear in its operating mode is made to produce a plot of radial and tangential deflections of the pinion and gear tooth surfaces which will occur when the gears are loaded during operation. The resultant plot is then inverted to produce a plot, or set of coordinates, which will define the path of travel of the gear tooth grinding wheel, which path is a mirror image of the plot of the finite element analysis. The resulting gears, when subjected to operating loads, will thus be deflected tangentially and radially to their optimum operating, or theoretical true involute, positions so as to produce quieter, smoother, and more evenly loaded gear trains.

  15. Modular gear bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2009-01-01

    A gearing system using modular gear bearing components. Each component is composed of a core, one or more modules attached to the core and two or more fastening modules rigidly attaching the modules to the core. The modules, which are attached to the core, may consist of gears, rollers or gear bearing components. The core orientation affects the orientation of the modules attached to the core. This is achieved via the keying arrangement of the core and the component modules that attach to the core. Such an arrangement will also facilitate the phase tuning of gear modules with respect to the core and other gear modules attached to the core.

  16. An electric control for an electrohydraulic active control aircraft landing gear

    NASA Technical Reports Server (NTRS)

    Ross, I.; Edson, R.

    1979-01-01

    An electronic controller for an electrohydraulic active control aircraft landing gear was developed. Drop tests of a modified gear from a 2722 Kg (6000 lbm) class of airplane were conducted to illustrate controller performance. The results indicate that the active gear effects a force reduction, relative to that of the passive gear, from 9 to 31 percent depending on the aircraft sink speed and the static gear pressure.

  17. Anti-backlash gear bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2009-01-01

    A gear bearing having a first gear and a second gear, each having a plurality of teeth. Each gear operates on two non-parallel surfaces of the opposing gear teeth to perform both gear and bearing functions simultaneously. The gears are moving at substantially the same speed at their contact points. The gears may be roller gear bearings or phase-shifted gear bearings, and may be arranged in a planet/sun system or used as a transmission. One preferred embodiment discloses and describes an anti-backlash feature to counter ''dead zones'' in the gear bearing movement.

  18. Magnetic gear backup

    NASA Technical Reports Server (NTRS)

    Shefke, R. A.

    1970-01-01

    Backup clutch for magnetic gear operates only in case of slippage. Contacting a pin arrangement in the driven gear, the clutch provides extra force for continuing output. It does not interfere with normal, noncontact action.

  19. Gear bearing drive

    NASA Technical Reports Server (NTRS)

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  20. Gear mesh stiffness and load sharing in planetary gearing

    NASA Technical Reports Server (NTRS)

    Kasuba, R.; August, R.

    1984-01-01

    An interactive computerized analysis was developed for determining load sharing among planetary gears. The load sharing is established as a function of transmitted torque, degree of sun gear fixity, component flexibility, gear tooth quality, and phasing of individual planet gears. A nonlinear variable gear tooth mesh stiffness model was used to simulate the sun/plant and planet/ring gear meshes. The determined load sharing and gear mesh stiffness parameters then can be used for the subsequent assessment of dynamic load factors.

  1. Landing gear noise attenuation

    NASA Technical Reports Server (NTRS)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  2. Phase-Oriented Gear Systems

    NASA Technical Reports Server (NTRS)

    Vranish, John M.

    2007-01-01

    Phase-oriented gear systems are differential planetary transmissions in which each planet gear has two sets of unequal numbers of teeth indexed at prescribed relative angles (phases). The figure illustrates an application of the phase-oriented gearing concept to a relatively simple speed-reducing differential planetary transmission that includes a sun gear, an idler gear, three identical planet gears, a ground internal ring gear, and an output internal ring gear. Typically, the ground internal ring gear and output internal ring gear have different numbers of teeth, giving rise to a progressive and periodic phase shift between the corresponding pairs of teeth engaged by each successive planet gear. To accommodate this phase shift, it is necessary to introduce a compensating phase shift between the ground-gear-engaging and output-gearengaging sections of each planet gear. This is done by individually orienting each planet gear

  3. Modelling polymer draft gears

    NASA Astrophysics Data System (ADS)

    Wu, Qing; Yang, Xiangjian; Cole, Colin; Luo, Shihui

    2016-09-01

    This paper developed a new and simple approach to model polymer draft gears. Two types of polymer draft gears were modelled and compared with experimental data. Impact characteristics, in-train characteristics and frequency responses of these polymer draft gears were studied and compared with those of a friction draft gear. The impact simulations show that polymer draft gears can withstand higher impact speeds than the friction draft gear. Longitudinal train dynamics simulations show that polymer draft gears have significantly longer deflections than friction draft gears in normal train operations. The maximum draft gear working velocities are lower than 0.2 m/s, which are significantly lower than the impact velocities during shunting operations. Draft gears' in-train characteristics are similar to their static characteristics but are very different from their impact characteristics; this conclusion has also been reached from frequency response simulations. An analysis of gangway bridge plate failures was also conducted and it was found that they were caused by coupler angling behaviour and long draft gear deflections.

  4. Toward dynamic model-based prognostics for transmission gears

    NASA Astrophysics Data System (ADS)

    Wang, Wenyi

    2002-07-01

    This paper presents a novel methodology for the diagnosis and prognosis of crucial gear faults, such as gear tooth fatigue cracking. Currently, an effective detection of tooth cracking can be achieved by using the autoregressive (AR) modeling approach, where the gear vibration signal is modeled by an AR model and gear tooth cracking is detected by identifying the sudden changes in the model's error signal. The model parameters can be estimated under the criteria of minimum power or maximum kurtosis of model errors. However, these model parameters possess no physical meaning about the monitored gear system. It is proposed that the AR model be replaced by a gear dynamics model (GDM) that contains physically meaningful parameters, such as mass, damping and stiffness. By identifying and tracking the changes in the parameters, it is possible to make diagnosis and prognosis of gear faults. For example, a reduction in mesh stiffness may indicate cracking of a gear tooth. Towards physical model-based prognosis, an adaptive (or optimization) strategy has been developed for approximating a gear signal using a simplified gear signal model. Preliminary results show that this strategy provides a feasible adaptive process for updating model parameters based on measured gear signal.

  5. A review of gear housing dynamics and acoustics literature

    NASA Technical Reports Server (NTRS)

    Singh, Rajendra; Lim, Teik Chin

    1988-01-01

    A review of the available literature on gear housing vibration and noise reduction is presented. Analytical and experimental methodologies used for bearing dynamics, housing vibration and noise, mounts and suspensions, and the overall geared and housing system are discussed. Typical design guidelines as outlined by various investigators are given.

  6. New Methods for Improved Double Circular-Arc Helical Gears

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Lu, Jian

    1997-01-01

    The authors have extended the application of double circular-arc helical gears for internal gear drives. The geometry of the pinion and gear tooth surfaces has been determined. The influence of errors of alignment on the transmission errors and the shift of the bearing contact have been investigated. Application of a predesigned parabolic function for the reduction of transmission errors was proposed. Methods of grinding of the pinion-gear tooth surfaces by a disk-shaped tool and a grinding worm were proposed.

  7. Study of novel concepts of power transmission gears

    NASA Technical Reports Server (NTRS)

    Rivin, Eugene I.

    1991-01-01

    Two concepts in power transmission gear design are proposed which provide a potential for large noise reduction and for improving weight to payload ratio due to use of advanced fiber reinforced and ceramic materials. These concepts are briefly discussed. Since both concepts use ultrathin layered rubber-metal laminates for accommodating limited travel displacements, properties of the laminates, such as their compressive strength, compressive and shear moduli were studied. Extensive testing and computational analysis were performed on the first concept gears (laminate coated conformal gears). Design and testing of the second conceptual design (composite gear with separation of sliding and rolling motions) are specifically described.

  8. Gear sound levels with various tooth contact ratios and forms

    NASA Technical Reports Server (NTRS)

    Lenski, Joseph W., Jr.; Spencer, Robert H.; Drago, Raymond J.; Valco, Mark J.; Oswald, Fred B.

    1993-01-01

    The real noise reduction benefits which may be obtained through the use of one gear tooth form as compared to another is an important design parameter for any geared system, especially for helicopters in which both weight and reliability are very important factors. The design and testing of nine sets of gears which are as identical as possible except for their basic tooth geometry are described. Noise measurements were made at various combinations of load and speed for each gear set so that direct comparisons could be made. The resultant data was analyzed so that valid conclusions could be drawn and interpreted for design use.

  9. 12. TRANSMISSION GEARING SHOWING RELATION TO SEGMENT GEAR ON WATERWHEEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. TRANSMISSION GEARING SHOWING RELATION TO SEGMENT GEAR ON WATERWHEEL william E. Barrett, photographer, 1973 (copy negative) - Thomas Shepherd's Grist Mill, High Street Vicinity, Shepherdstown, Jefferson County, WV

  10. Liquid rocket engine turbopump gears

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Design and fabrication of gear drives for rocket engine turbopumps are described in the sequence encountered during the design process as follows: (1) selection of overall arrangement; (2) selection of gear type; (3) preliminary sizing; (4) lubrication system design; (5) detail tooth design; (6) selection of gear materials; and (7) gear fabrication and testing as it affects the design. The description is oriented towards the use of involute spur gears, although reference material for helical gears is also cited.

  11. The relative noise levels of parallel axis gear sets with various contact ratios and gear tooth forms

    NASA Astrophysics Data System (ADS)

    Drago, Raymond J.; Lenski, Joseph W., Jr.; Spencer, Robert H.; Valco, Mark; Oswald, Fred B.

    1993-12-01

    The real noise reduction benefits which may be obtained through the use of one gear tooth form as compared to another is an important design parameter for any geared system, especially for helicopters in which both weight and reliability are very important factors. This paper describes the design and testing of nine sets of gears which are as identical as possible except for their basic tooth geometry. Noise measurements were made at various combinations of load and speed for each gear set so that direct comparisons could be made. The resultant data was analyzed so that valid conclusions could be drawn and interpreted for design use.

  12. The relative noise levels of parallel axis gear sets with various contact ratios and gear tooth forms

    NASA Technical Reports Server (NTRS)

    Drago, Raymond J.; Lenski, Joseph W., Jr.; Spencer, Robert H.; Valco, Mark; Oswald, Fred B.

    1993-01-01

    The real noise reduction benefits which may be obtained through the use of one gear tooth form as compared to another is an important design parameter for any geared system, especially for helicopters in which both weight and reliability are very important factors. This paper describes the design and testing of nine sets of gears which are as identical as possible except for their basic tooth geometry. Noise measurements were made at various combinations of load and speed for each gear set so that direct comparisons could be made. The resultant data was analyzed so that valid conclusions could be drawn and interpreted for design use.

  13. An electronic control for an electrohydraulic active control landing gear for the F-4 aircraft

    NASA Technical Reports Server (NTRS)

    Ross, I.

    1982-01-01

    A controller for an electrohydraulic active control landing gear was developed for the F-4 aircraft. A controller was modified for this application. Simulation results indicate that during landing and rollout over repaired bomb craters the active gear effects a force reduction, relative to the passive gear, or approximately 70%.

  14. Impact of NiB Coating on the Efficiency, Scuffing, and Wear of Gear Contacts

    DTIC Science & Technology

    2013-05-01

    dependent (mechanical) power losses. This was confirmed by Talbot et al. (11) through planetary gear -set power-loss experiments as well. Some of...ground or shaved surfaces. Gear experiments (4, 5, 8, 14) show sizable reductions in spur or planetary gear -mesh mechanical power losses of shaved...D.; Kahraman, A.; Singh, A. An Experimental Investigation of the Efficiency of Planetary Gear Sets. Journal of Mechanical Design 2012, 134 (2

  15. Airplane landing gear

    NASA Technical Reports Server (NTRS)

    Maiorca, Salvatore

    1931-01-01

    This report presents an investigation of the design and construction of various types of landing gears. Some of the items discussed include: chassises, wheels, shock absorbers (rubber disk and rubber cord), as well as oleopneumatic shock absorbers. Various types of landing gears are also discussed such as the Messier, Bendix, Vickers, and Bleriot.

  16. Gear Crack Propagation Investigation

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Reduced weight is a major design goal in aircraft power transmissions. Some gear designs incorporate thin rims to help meet this goal. Thin rims, however, may lead to bending fatigue cracks. These cracks may propagate through a gear tooth or into the gear rim. A crack that propagates through a tooth would probably not be catastrophic, and ample warning of a failure could be possible. On the other hand, a crack that propagates through the rim would be catastrophic. Such cracks could lead to disengagement of a rotor or propeller from an engine, loss of an aircraft, and fatalities. To help create and validate tools for the gear designer, the NASA Lewis Research Center performed in-house analytical and experimental studies to investigate the effect of rim thickness on gear-tooth crack propagation. Our goal was to determine whether cracks grew through gear teeth (benign failure mode) or through gear rims (catastrophic failure mode) for various rim thicknesses. In addition, we investigated the effect of rim thickness on crack propagation life. A finite-element-based computer program simulated gear-tooth crack propagation. The analysis used principles of linear elastic fracture mechanics, and quarter-point, triangular elements were used at the crack tip to represent the stress singularity. The program had an automated crack propagation option in which cracks were grown numerically via an automated remeshing scheme. Crack-tip stress-intensity factors were estimated to determine crack-propagation direction. Also, various fatigue crack growth models were used to estimate crack-propagation life. Experiments were performed in Lewis' Spur Gear Fatigue Rig to validate predicted crack propagation results. Gears with various backup ratios were tested to validate crack-path predictions. Also, test gears were installed with special crack-propagation gages in the tooth fillet region to measure bending-fatigue crack growth. From both predictions and tests, gears with backup ratios

  17. Partial tooth gear bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  18. Gear noise origins

    NASA Astrophysics Data System (ADS)

    Mark, W. D.

    1985-01-01

    Each pair of meshing gears in a transmission gives rise to a source of vibratory excitation that can result in the radiation of sound. Each such source is most conveniently characterized as a displacement form of excitation generally referred to as the static transmission error of the gear pair. Contributions to the frequency spectrum of the static transmission error of spur and helical gears arising from tooth and gear body elastic deformations and from deviations of tooth surfaces from perfect involute surfaces are considered. Tooth surface deviations are decomposed into contributions giving rise to tooth meshing harmonic excitations and rotational harmonic or sideband excitations. Various types of gear tooth errors are defined and the contributions of these errors to different parts of the frequency spectrum are described. The attenuating effect on the static transmission error spectrum arising from the smoothing action of multiple tooth contact is explained.

  19. Design of Gear Drives With High Gear Ratio

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Fuentes, Alfonso; Vecchiato, Daniele; Gonzalez-Perez, Ignacio

    2005-01-01

    A three part paper to describe the results of several gear drive types with a high gear ratio is presented. A single stage planetary gear train with double helical gears is described with methods to reduce transmission errors and improve load distribution by regulating backlash during assembly. A new arrangement for face gear is also described. This new mechanism can perform rotations between axes that are collinear and intersected. Finally the design and simulation of an isostatic planetary gear train is presented. Conditions that can lead to noise and vibration of the planetary gear drive are described.

  20. Effects of Planetary Gear Ratio on Mean Service Life

    NASA Technical Reports Server (NTRS)

    Savage, M.; Rubadeux, K. L.; Coe, H. H.

    1996-01-01

    Planetary gear transmissions are compact, high-power speed reductions which use parallel load paths. The range of possible reduction ratios is bounded from below and above by limits on the relative size of the planet gears. For a single plane transmission, the planet gear has no size at a ratio of two. As the ratio increases, so does the size of the planets relative to the sizes of the sun and ring. Which ratio is best for a planetary reduction can be resolved by studying a series of optimal designs. In this series, each design is obtained by maximizing the service life for a planetary with a fixed size, gear ratio, input speed power and materials. The planetary gear reduction service life is modeled as a function of the two-parameter Weibull distributed service lives of the bearings and gears in the reduction. Planet bearing life strongly influences the optimal reduction lives which point to an optimal planetary reduction ratio in the neighborhood of four to five.

  1. High-Ratio Gear Train

    NASA Technical Reports Server (NTRS)

    Lefever, A. E.

    1982-01-01

    Proposed arrangement of two connected planetary differentials results in gear ratio many times that obtainable in conventional series gear assembly of comparable size. Ratios of several thousand would present no special problems. Selection of many different ratios is available with substantially similar gear diameters. Very high gear ratios would be obtained from small mechanism.

  2. Gear assembly for automobile transmission

    SciTech Connect

    Ikemoto, K.; Tera Kura, Y.; Miyake, T.

    1986-03-25

    This patent describes a gear assembly including a pair of driving and driven gears permanently in meshing engagement with each other to provide a torque transmission therebetween. The driven gear is formed at one side thereof with a boss portion, and an additional gear axially slidable and rotatable on the boss portion of the driven gear and is permanently in meshing engagement with the driving gear to rotate at a gear ratio different from that of the driving and driven gears, additional gear is also resiliently in contact with a synchronizer mechanism assembled adjaecnt to the additional gear and having a spline piece fixed to the boss portion of the driven gear. The improvement wherein a toothed portion of the driven gear is formed at one end thereof with an annual stepped portion for provision of a predetermined annular gap between the additional gear and the one end face of the toothed portion of the driven gear. The resilient means is a waveshaped ring spring arranged in surrounding relationship with the boss portion of the driven gear and is engaged at its one end face with the additional gear and at its other end face with the spline piece of the synchronizer mechanism.

  3. Aircraft landing gear systems

    NASA Technical Reports Server (NTRS)

    Tanner, John A. (Editor)

    1990-01-01

    Topics presented include the laboratory simulation of landing gear pitch-plane dynamics, a summary of recent aircraft/ground vehicle friction measurement tests, some recent aircraft tire thermal studies, and an evaluation of critical speeds in high-speed aircraft. Also presented are a review of NASA antiskid braking research, titanium matrix composite landing gear development, the current methods and perspective of aircraft flotation analysis, the flow rate and trajectory of water spray produced by an aircraft tire, and spin-up studies of the Space Shuttle Orbiter main gear tire.

  4. Robotic endoscope motor module and gearing design.

    PubMed

    Oliveira, Jillian M; Chen, Yi; Hunter, Ian W

    2011-01-01

    Actuation of a robotic endoscope with increased torque output is presented. This paper will specifically focus on the motor module section of a robotic endoscope, which comprises of a pair of motors and gear reduction assemblies. The results for the endoscope and biopsy tool stiffness, as well as the stall force and force versus speed characteristics of the motor module assembly are shown. The scope stiffness was found to be 0.006 N/degree and additional stiffness of the biopsy tools were found to be in the range of 0.09 to 0.13 N/degree. Calculations for worm gearing and efficiency are discussed.

  5. Computing Stresses In Spur Gears

    NASA Technical Reports Server (NTRS)

    Oswald, F. B.; Lin, H. H.

    1995-01-01

    Dynamic Analysis of Spur Gear Transmissions (DANST) developed as easy-to-use program for static and dynamic analysis of spur-gear systems. Used for parametric studies to predict effects of operating speed, torque, stiffness, damping, inertia, and tooth profile on dynamic loads and tooth-bending stresses in spur gears. Performs geometric modeling and dynamic analysis for low- or high-contact-ratio spur gears. Simulates gear systems with contact ratios ranging from one to three. Written in FORTRAN 77.

  6. Gear Fatigue Diagnostics and Prognostics

    DTIC Science & Technology

    2013-01-01

    one for single gear tooth fatigue, and one for gear-on-gear dynamometer-based tester ) we have been collecting crack initiation and crack propagation...fatigue tester ); and torque, angular speed, vibration, temperature, and crack-propagation (gear-on-gear dynamometer-based tester ). The main outcome...Description The test consists of two set of tests on a dynamometer and one set of test on the fatigue tester and some additional activities. Fig

  7. 50 CFR 622.188 - Required gear, authorized gear, and unauthorized gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO..., sea bass pot, and spearfishing gear. (c) Unauthorized gear. All gear types other than those specified... unauthorized gear on board may not be transferred at sea, regardless of where such transfer takes place,...

  8. 50 CFR 622.188 - Required gear, authorized gear, and unauthorized gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO..., sea bass pot, and spearfishing gear. (c) Unauthorized gear. All gear types other than those specified... unauthorized gear on board may not be transferred at sea, regardless of where such transfer takes place,...

  9. Two stage gear tooth dynamics program

    NASA Technical Reports Server (NTRS)

    Boyd, Linda S.

    1989-01-01

    The epicyclic gear dynamics program was expanded to add the option of evaluating the tooth pair dynamics for two epicyclic gear stages with peripheral components. This was a practical extension to the program as multiple gear stages are often used for speed reduction, space, weight, and/or auxiliary units. The option was developed for either stage to be a basic planetary, star, single external-external mesh, or single external-internal mesh. The two stage system allows for modeling of the peripherals with an input mass and shaft, an output mass and shaft, and a connecting shaft. Execution of the initial test case indicated an instability in the solution with the tooth paid loads growing to excessive magnitudes. A procedure to trace the instability is recommended as well as a method of reducing the program's computation time by reducing the number of boundary condition iterations.

  10. Improving backdrivability in geared rehabilitation robots.

    PubMed

    Nef, Tobias; Lum, Peter

    2009-04-01

    Many rehabilitation robots use electric motors with gears. The backdrivability of geared drives is poor due to friction. While it is common practice to use velocity measurements to compensate for kinetic friction, breakaway friction usually cannot be compensated for without the use of an additional force sensor that directly measures the interaction force between the human and the robot. Therefore, in robots without force sensors, subjects must overcome a large breakaway torque to initiate user-driven movements, which are important for motor learning. In this technical note, a new methodology to compensate for both kinetic and breakaway friction is presented. The basic strategy is to take advantage of the fact that, for rehabilitation exercises, the direction of the desired motion is often known. By applying the new method to three implementation examples, including drives with gear reduction ratios 100-435, the peak breakaway torque could be reduced by 60-80%.

  11. Planetary gear unit

    SciTech Connect

    Takahashi, S.

    1986-10-07

    This patent describes a planetary gear unit for the transmission of a motor vehicle, comprising: a first planetary gear unit which includes a pinion shaft, a planet pinion rotatably mounted on the pinion shaft, a sun gear engaging the planet pinion, and an arm member supporting the pinion shaft and having an extending portion extending to a point adjacent the sun gear; a thrust washer contacting the arm member, the thrust washer having radiating conduit means formed on a contacting surface thereof so as to communicate an inner circumference of the extending portion of the arm member with the pinion shaft, the pinion shaft having a conduit formed therein so as to communicate with the radiating conduit means with an inner surface of the planet pinion wherein the radiating conduit means further comprises uniform spaced bevel surfaces and grooves in communication with the bevel surfaces.

  12. Communication: Molecular gears.

    PubMed

    Burnell, E Elliott; de Lange, Cornelis A; Meerts, W Leo

    2016-09-07

    The (1)H nuclear magnetic resonance spectrum of hexamethylbenzene orientationally ordered in the nematic liquid crystal ZLI-1132 is analysed using covariance matrix adaptation evolution strategy. The spectrum contains over 350 000 lines with many overlapping transitions, from which four independent direct dipolar couplings are obtained. The rotations of the six methyl groups appear to be correlated due to mutual steric hindrance. Adjacent methyl groups show counter-rotating or geared motion. Hexamethylbenzene thus behaves as a molecular hexagonal gear.

  13. Gear tooth stress measurements of two helicopter planetary stages

    NASA Technical Reports Server (NTRS)

    Krantz, Timothy L.

    1992-01-01

    Two versions of the planetary reduction stages from U.S. Army OH-58 helicopter main rotor transmissions were tested at NASA Lewis. One sequential and one nonsequential planetary were tested. Sun gear and ring gear teeth strains were measured, and stresses were calculated from the strains. The alternating stress at the fillet of both the loaded and unloaded sides of the teeth and at the root of the sun gear teeth are reported. Typical stress variations as the gear tooth moves through mesh are illustrated. At the tooth root location of the thin rimmed sun gear, a significant stress was produced by a phenomenon other than the passing of a planet gear. The load variation among the planets was studied. Each planet produced its own distinctive load distribution on the ring and sun gears. The load variation was less for a three planet, nonsequential design as compared to that of a four planet, sequential design. The reported results enhance the data base for gear stress levels and provide data for the validation of analytical methods.

  14. Gear tooth stress measurements of two helicopter planetary stages

    NASA Astrophysics Data System (ADS)

    Krantz, Timothy L.

    Two versions of the planetary reduction stages from U.S. Army OH-58 helicopter main rotor transmissions were tested at NASA Lewis. One sequential and one nonsequential planetary were tested. Sun gear and ring gear teeth strains were measured, and stresses were calculated from the strains. The alternating stress at the fillet of both the loaded and unloaded sides of the teeth and at the root of the sun gear teeth are reported. Typical stress variations as the gear tooth moves through mesh are illustrated. At the tooth root location of the thin rimmed sun gear, a significant stress was produced by a phenomenon other than the passing of a planet gear. The load variation among the planets was studied. Each planet produced its own distinctive load distribution on the ring and sun gears. The load variation was less for a three planet, nonsequential design as compared to that of a four planet, sequential design. The reported results enhance the data base for gear stress levels and provide data for the validation of analytical methods.

  15. Grinding Induced Changes in Residual Stresses of Carburized Gears

    SciTech Connect

    Lemaster, Robert A; Boggs, Bryan L; Bunn, Jeffrey R; Hubbard, Camden R; Watkins, Thomas R

    2009-01-01

    This paper presents the results of a study performed to measure the change in residual stress that results from the finish grinding of carburized gears. Residual stresses were measured in five gears using the x-ray diffraction equipment in the Large Specimen Residual Stress Facility at Oak Ridge National Laboratory. Two of the gears were hobbed, carburized, quenched and tempered, but not finished. The remaining three gears were processed similarly, but were finish ground. The residual stresses were measured at 64 different locations on a tooth from each gear. Residual stresses were also measured at fewer points on other teeth to determine the tooth-to-tooth variation. Tooth profile measurements were made of the finished and unfinished gear samples. The results show a fairly uniform and constant compressive residual field in the nonfinished gears. There was a significant reduction in the average residual stress measured in the finished gears. Additionally, there was a significant increase in the variability of the residual stress that was introduced by the grinding process. Analysis of the data suggests a linear relationship between the change in average residual stress and the amount of material removed by the grinding process.

  16. LIME KILN BUILDING, KILN BOTTOM SHOWING ROTATOR GEAR. (GEAR IS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LIME KILN BUILDING, KILN BOTTOM SHOWING ROTATOR GEAR. (GEAR IS POINTED DOWN FOR PROPER ORIENTATION). - Solvay Process Company, Lime Kiln Building, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  17. Magnetic Gearing Versus Conventional Gearing in Actuators for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Puchhammer, Gregor

    2014-01-01

    Magnetic geared actuators (MGA) are designed to perform highly reliable, robust and precise motion on satellite platforms or aerospace vehicles. The design allows MGA to be used for various tasks in space applications. In contrast to conventional geared drives, the contact and lubrication free force transmitting elements lead to a considerable lifetime and range extension of drive systems. This paper describes the fundamentals of magnetic wobbling gears (MWG) and the deduced inherent characteristics, and compares conventional and magnetic gearing.

  18. Analytical investigation of the landing dynamics of a large airplane with a load-control system in the main landing gear

    NASA Technical Reports Server (NTRS)

    Mcgehee, J. R.; Carden, H. D.

    1979-01-01

    The results of an evaluation of an active load-control landing gear computer program (ACOLAG) for predicting the landing dynamics of airplanes with passive and active main gears are presented. ACOLAG was used in an analytical investigation of the landing dynamics of a large airplane with both passive and active main gears. It was concluded that the program is valid for predicting the landing dynamics of airplanes with both passive and active main gears. It was shown that the active gear reduces airframe-gear forces and airplane motions following initial impact, and has the potential for significant reductions in structural fatigue damage relative to that which occurs with the passive gear.

  19. Gear crack propagation investigations

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Ballarini, Roberto

    1996-01-01

    Analytical and experimental studies were performed to investigate the effect of gear rim thickness on crack propagation life. The FRANC (FRacture ANalysis Code) computer program was used to simulate crack propagation. The FRANC program used principles of linear elastic fracture mechanics, finite element modeling, and a unique re-meshing scheme to determine crack tip stress distributions, estimate stress intensity factors, and model crack propagation. Various fatigue crack growth models were used to estimate crack propagation life based on the calculated stress intensity factors. Experimental tests were performed in a gear fatigue rig to validate predicted crack propagation results. Test gears were installed with special crack propagation gages in the tooth fillet region to measure bending fatigue crack growth. Good correlation between predicted and measured crack growth was achieved when the fatigue crack closure concept was introduced into the analysis. As the gear rim thickness decreased, the compressive cyclic stress in the gear tooth fillet region increased. This retarded crack growth and increased the number of crack propagation cycles to failure.

  20. Computerized Design and Generation of Low-Noise Gears with Localized Bearing Contact

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Chen, Ningxin; Chen, Jui-Sheng; Lu, Jian; Handschuh, Robert F.

    1995-01-01

    The results of research projects directed at the reduction of noise caused by misalignment of the following gear drives: double-circular arc helical gears, modified involute helical gears, face-milled spiral bevel gears, and face-milled formate cut hypoid gears are presented. Misalignment in these types of gear drives causes periodic, almost linear discontinuous functions of transmission errors. The period of such functions is the cycle of meshing when one pair of teeth is changed for the next. Due to the discontinuity of such functions of transmission errors high vibration and noise are inevitable. A predesigned parabolic function of transmission errors that is able to absorb linear discontinuous functions of transmission errors and change the resulting function of transmission errors into a continuous one is proposed. The proposed idea was successfully tested using spiral bevel gears and the noise was reduced a substantial amount in comparison with the existing design. The idea of a predesigned parabolic function is applied for the reduction of noise of helical and hypoid gears. The effectiveness of the proposed approach has been investigated by developed TCA (tooth contact analysis) programs. The bearing contact for the mentioned gears is localized. Conditions that avoid edge contact for the gear drives have been determined. Manufacturing of helical gears with new topology by hobs and grinding worms has been investigated.

  1. A Program for Gear Calculations.

    ERIC Educational Resources Information Center

    Bisbee, Kolak K.; Hawkins, Harry M.

    1982-01-01

    Presents a microcomputer program (designed for Apple II but it can be modified) used to calculate various dimensions relative to a spur gear. Basic terms are identified and a program listing for gear calculations is included. (CT)

  2. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1982-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory.

  3. Kinematic precision of gear trains

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1983-01-01

    Kinematic precision is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic precision of gear trains is described. The method is based on the exact kinematic relations for the contact point motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic precision theory. Previously announced in STAR as N82-32733

  4. LSRA with Shuttle main gear

    NASA Technical Reports Server (NTRS)

    1993-01-01

    A space shuttle landing gear system is visible between the two main landing gear components on this NASA CV-990, modified as a Landing Systems Research Aircraft. The space shuttle landing gear test unit, operated by a high-pressure hydraulic system, allowed engineers to assess and document the performance of space shuttle main and nose landing gear systems, tires and wheel assemblies, plus braking and nose wheel steering performance.

  5. Topology of modified helical gears

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Zhang, J.; Handschuh, R. F.; Coy, J. J.

    1989-01-01

    The topology of several types of modified surfaces of helical gears is proposed. The modified surfaces allow absorption of a linear or almost linear function of transmission errors. These errors are caused by gear misalignment and an improvement of the contact of gear tooth surfaces. Principles and corresponding programs for computer aided simulation of meshing and contact of gears have been developed. The results of this investigation are illustrated with numerical examples.

  6. A superconducting magnetic gear

    NASA Astrophysics Data System (ADS)

    Campbell, A. M.

    2016-05-01

    A comparison is made between a magnetic gear using permanent magnets and superconductors. The objective is to see if there are any fundamental reasons why superconducting magnets should not provide higher power densities than permanent magnets. The gear is based on the variable permeability design of Attilah and Howe (2001 IEEE Trans. Magn. 37 2844-46) in which a ring of permanent magnets surrounding a ring of permeable pole pieces with a different spacing gives an internal field component at the beat frequency. Superconductors can provide much larger fields and forces but will saturate the pole pieces. However the gear mechanism still operates, but in a different way. The magnetisation of the pole pieces is now constant but rotates with angle at the beat frequency. The result is a cylindrical Halbach array which produces an internal field with the same symmetry as in the linear regime, but has an analytic solution. In this paper a typical gear system is analysed with finite elements using FlexPDE. It is shown that the gear can work well into the saturation regime and that the Halbach array gives a good approximation to the results. Replacing the permanent magnets with superconducting tapes can give large increases in torque density, and for something like a wind turbine a combined gear and generator is possible. However there are major practical problems. Perhaps the most fundamental is the large high frequency field which is inevitably present and which will cause AC losses. Also large magnetic fields are required, with all the practical problems of high field superconducting magnets in rotating machines. Nevertheless there are ways of mitigating these difficulties and it seems worthwhile to explore the possibilities of this technology further.

  7. Flightworthy active control landing gear for a supersonic aircraft

    NASA Technical Reports Server (NTRS)

    Ross, I.

    1980-01-01

    A flightworthy active control landing gear system for a supersonic aircraft was designed to minimize aircraft loads during takeoff, impact, rollout, and taxi. The design consists of hydromechanical modifications to the existing gear and the development of a fail-safe electronic controller. analytical RESULTS INDICATE that for an aircraft sink rate of 0.914 m/sec (3 ft/sec) the system achieves a peak load reduction of 36% during landing impact.

  8. Theory of gearing

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.

    1989-01-01

    Basic mathematical problems on the theory of gearing are covered in this book, such as the necessary and sufficient conditions of envelope existence, relations between principal curvatures and directions for surfaces of mating gears. Also included are singularities of surfaces accompanied by undercutting the process of generation, the phenomena of envelope of lines of contact, and the principles for generation of conjugate surfaces. Special attention is given to the algorithms for computer aided simulation of meshing and tooth contact. This edition was complemented with the results of research recently performed by the author and his doctoral students. The book contains sample problems and also problems for the reader to solve.

  9. Electronic automatic gear transmission control apparatus

    SciTech Connect

    Koshizawa, T.

    1989-04-25

    This patent describes an electronic automatic gear transmission control apparatus having a shift schedule map for commanding an optimum gear position based on a vehicle speed signal and an accelerator opening signal, the electronic automatic gear transmission control apparatus comprising: first means for comparing a gear position commanded by the shift schedule map with a present gear position; second means for effecting a gear shift to a gear position which is one gear position higher than the present gear position and for restraining a gear shift to the commanded gear position for a prescribed period of time, if the commanded gear position requires an upshift to a gear position which is two or more gear positions higher than the present gear position as a result of the comparison performed by the first means; and third means for holding the gear position which is one gear position higher than the present gear position until an accelerator pedal is depressed again, when the accelerator opening signal indicates an idling position while the gear shift up to the gear position which is one gear position higher than the present gear position, is being effected by the second means.

  10. Bacteria turn tiny gears

    SciTech Connect

    2009-01-01

    Swarms of bacteria turn two 380-micron long gears, opening the possibility of building hybrid biological machines at the microscopic scale. Read more at Wired: http://www.wired.com/wiredscience/2009/12/bacterial-micro-machine/#more-15684 or Scientific American: http://www.scientificamerican.com/article.cfm?id=brownian-motion-bacteria

  11. Side gear mounting for differential assembly

    SciTech Connect

    Pederson, H.

    1989-02-21

    A differential gear assembly is described of the type which includes a differential gear housing having means for receiving a pair of axle ends together with a pair of substantially axially aligned side gears coupled to the pair of axle ends for rotation therewith, the side gears having helix angles inclined in the same direction with respect to the axes of rotation thereof, characterized in that the gear assembly includes means for preventing axial thrust forces developed by one of the side gears from loading the other of the side gears. The preventing means includes means for separating the side gears such that there is no direct or indirect engagement between confronting end faces of the side gears when thrust forces of one of the side gears are directed toward the other of the side gears; and the means for axially separating the side gears includes a pair of overlapping elements associated with one of the side gears of the gear housing.

  12. Improve planetary gear vibration analysis

    SciTech Connect

    Hussain, M.S. )

    1993-05-01

    To diagnose problems in rotating machinery, an analyst must be able to identify the frequencies present in the data. In the case of two gears with fixed centerlines, the generated gearmesh frequency is simply calculated as the number of teeth on one gear times its rotational speed (in Hz, cpm, etc.) But when the shaft centerlines move relative to each other, as with a planet gear orbiting around a sun gear, gearmesh frequency is no longer equal to gear rotational sped times the gear's number of teeth. In this case, you must calculate the relative speed between planet carrier and gear with the fixed centerline to obtain gearmesh frequency. The paper presents the equations necessary to calculate gearmesh frequencies in order to diagnose problems.

  13. Displaceable Gear Torque Controlled Driver

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (Inventor)

    1997-01-01

    Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

  14. The design of worm gear sets

    NASA Technical Reports Server (NTRS)

    Razzaghi, Andrea I.

    1987-01-01

    A method is presented for designing worm gear sets to meet torque multiplication requirements. First, the fundamentals of worm gear design are discussed, covering worm gear set nomenclature, kinematics and proportions, force analysis, and stress analysis. Then, a suggested design method is discussed, explaining how to take a worm gear set application, and specify a complete worm gear set design. The discussions are limited to cylindrical worm gear sets that have a 90 deg shaft angle between the worm and the mating gear.

  15. A new approach to complete aircraft landing gear noise prediction

    NASA Astrophysics Data System (ADS)

    Lopes, Leonard V.

    This thesis describes a new landing gear noise prediction system developed at The Pennsylvania State University, called Landing Gear Model and Acoustic Prediction code (LGMAP). LGMAP is used to predict the noise of an isolated or installed landing gear geometry. The predictions include several techniques to approximate the aeroacoustic and aerodynamic interactions of landing gear noise generation. These include (1) a method for approximating the shielding of noise caused by the landing gear geometry, (2) accounting for local flow variations due to the wing geometry, (3) the interaction of the landing gear wake with high-lift devices, and (4) a method for estimating the effect of gross landing gear design changes on local flow and acoustic radiation. The LGMAP aeroacoustic prediction system has been created to predict the noise generated by a given landing gear. The landing gear is modeled as a set of simple components that represent individual parts of the structure. Each component, ranging from large to small, is represented by a simple geometric shape and the unsteady flow on the component is modeled based on an individual characteristic length, local flow velocity, and the turbulent flow environment. A small set of universal models is developed and applied to a large range of similar components. These universal models, combined with the actual component geometry and local environment, give a unique loading spectrum and acoustic field for each component. Then, the sum of all the individual components in the complete configuration is used to model the high level of geometric complexity typical of current aircraft undercarriage designs. A line of sight shielding algorithm based on scattering by a two-dimensional cylinder approximates the effect of acoustic shielding caused by the landing gear. Using the scattering from a cylinder in two-dimensions at an observer position directly behind the cylinder, LGMAP is able to estimate the reduction in noise due to shielding

  16. Planetary gear train for automatic transmission

    SciTech Connect

    Hiraiwa, K.

    1987-04-28

    A planetary gear train is described for an automatic transmission, the planetary gear train having gear ratios including a first forward gear ratio and a reverse, the planetary gear train comprising: an input shaft; a basic planetary gearing including a first rotary element which is to be held stationary when the first gear ratio is established and also when the reverse is established, and a second rotary element which is to serve as an output member of the basic planetary gearing; an output planetary gear set including a ring gear, a sun gear and a pinion carrier; change speed means for establishing any desired one of the gear ratios; a clutch means for establishing a connection between the other one of the ring gear and the sun gear of the output planetary gear set and the first rotary element of the basic planetary gearing during operation with the first gear ratio and also during operation with the reverse, and a brake means for anchoring the other one of the ring gear and the sun gear of the output planetary gear set during operation with the reverse; and an output shaft connected to the pinion carrier of the output planetary gear set.

  17. Multi-mesh gear dynamics program evaluation and enhancements

    NASA Technical Reports Server (NTRS)

    Boyd, L. S.; Pike, J.

    1985-01-01

    A multiple mesh gear dynamics computer program was continually developed and modified during the last four years. The program can handle epicyclic gear systems as well as single mesh systems with internal, buttress, or helical tooth forms. The following modifications were added under the current funding: variable contact friction, planet cage and ring gear rim flexibility options, user friendly options, dynamic side bands, a speed survey option and the combining of the single and multiple mesh options into one general program. The modified program was evaluated by comparing calculated values to published test data and to test data taken on a Hamilton Standard turboprop reduction gear-box. In general, the correlation between the test data and the analytical data is good.

  18. Scoring of precision spur gears

    SciTech Connect

    Budinski, K.G. )

    1994-09-01

    A group of manufacturing machines employed precision spur gears as the timing mechanism for machine operations. These machines had worked successfully for about ten years with little or no problems with gear wear or deterioration. When new machines were brought on line with recently made gears there were immediate problems with gear tooth scoring. A laboratory study was conducted to determine if metallurgical conditions were related to the gear scoring. Recent gears were made from a modification of the alloy used in early gears. The new alloy has been modified to make it more resistant to softening in coating operations. Reciprocating wear tests and galling tests were conducted to compare the tribological characteristics of the old and new gear steels. It was determined that the threshold galling stress of the gear steels was strongly dependent on the hardness. The reciprocating wear tests indicated that the wear resistance was affected by the volume fraction of hard phases in the steels. The recommended short-term solution was to alter the tempering procedure for the steel to keep Rockwell C hardness above 60; the long-term solution was to change the gear material and lubrication.

  19. 49 CFR 230.89 - Reverse gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse...

  20. 46 CFR 28.885 - Cargo gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Cargo gear. 28.885 Section 28.885 Shipping COAST GUARD... Aleutian Trade Act Vessels § 28.885 Cargo gear. (a) The safe working load (SWL) for the assembled gear... the load the gear is approved to lift, excluding the weight of the gear itself. (b) All wire...

  1. 46 CFR 28.885 - Cargo gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Cargo gear. 28.885 Section 28.885 Shipping COAST GUARD... Aleutian Trade Act Vessels § 28.885 Cargo gear. (a) The safe working load (SWL) for the assembled gear... the load the gear is approved to lift, excluding the weight of the gear itself. (b) All wire...

  2. 46 CFR 28.885 - Cargo gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Cargo gear. 28.885 Section 28.885 Shipping COAST GUARD... Aleutian Trade Act Vessels § 28.885 Cargo gear. (a) The safe working load (SWL) for the assembled gear... the load the gear is approved to lift, excluding the weight of the gear itself. (b) All wire...

  3. 49 CFR 230.89 - Reverse gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse...

  4. 49 CFR 230.89 - Reverse gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse...

  5. 49 CFR 230.89 - Reverse gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse...

  6. 46 CFR 28.885 - Cargo gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Cargo gear. 28.885 Section 28.885 Shipping COAST GUARD... Aleutian Trade Act Vessels § 28.885 Cargo gear. (a) The safe working load (SWL) for the assembled gear... the load the gear is approved to lift, excluding the weight of the gear itself. (b) All wire...

  7. 49 CFR 230.89 - Reverse gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse...

  8. 46 CFR 28.885 - Cargo gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Cargo gear. 28.885 Section 28.885 Shipping COAST GUARD... Aleutian Trade Act Vessels § 28.885 Cargo gear. (a) The safe working load (SWL) for the assembled gear... the load the gear is approved to lift, excluding the weight of the gear itself. (b) All wire...

  9. Gear Drive Testing

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Philadelphia Gear Corporation used two COSMIC computer programs; one dealing with shrink fit analysis and the other with rotor dynamics problems in computerized design and test work. The programs were used to verify existing in-house programs to insure design accuracy by checking its company-developed computer methods against procedures developed by other organizations. Its specialty is in custom units for unique applications, such as Coast Guard ice breaking ships, steel mill drives, coal crusher, sewage treatment equipment and electricity.

  10. Worm Gear With Hydrostatic Engagement

    NASA Technical Reports Server (NTRS)

    Chaiko, Lev I.

    1994-01-01

    In proposed worm-gear transmission, oil pumped at high pressure through meshes between teeth of gear and worm coil. Pressure in oil separates meshing surfaces slightly, and oil reduces friction between surfaces. Conceived for use in drive train between gas-turbine engine and rotor of helicopter. Useful in other applications in which weight critical. Test apparatus simulates and measures some loading conditions of proposed worm gear with hydrostatic engagement.

  11. High-performance magnetic gears

    NASA Astrophysics Data System (ADS)

    Atallah, Kais; Calverley, Stuart D.; Howe, David

    2004-05-01

    Magnetic gearing may offer significant advantages such as reduced maintenance and improved reliability, inherent overload protection, and physical isolation between input and output shafts. Despite these advantages, it has received relatively little attention, to date, probably due to the poor torque transmission capability of proposed magnetic gears. The paper describes a magnetic gear topology, which combines a significantly higher torque transmission capability and a very high efficiency.

  12. Improvements in Spiral-Bevel Gears to Reduce Noise and Increase Strength

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Handschuh, Robert F.; Henry, Zachary S.; Litvin, Faydor L.

    1994-01-01

    Advanced-design spiral-bevel gears were tested in an OH-58D helicopter transmission using the NASA 500 hp Helicopter Transmission Test Stand. Four different gear designs were tested. The four designs tested were the current design of the OH-58D transmission, a higher-strength design the same as the current but with an increased fillet radius to reduce gear tooth bending stress, and two versions of a lower-noise design the same as the high-strength but with modified tooth geometry to reduce transmission error and noise. Noise, vibration, and tooth strain tests were performed and significant gear stress and noise reductions were achieved.

  13. Gears Based on Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Jaffe, Richard; Han, Jie; Globus, Al; Deardorff, Glenn

    2005-01-01

    Gears based on carbon nanotubes (see figure) have been proposed as components of an emerging generation of molecular- scale machines and sensors. In comparison with previously proposed nanogears based on diamondoid and fullerene molecules, the nanotube-based gears would have simpler structures and are more likely to be realizable by practical fabrication processes. The impetus for the practical development of carbon-nanotube- based gears arises, in part, from rapid recent progress in the fabrication of carbon nanotubes with prescribed diameters, lengths, chiralities, and numbers of concentric shells. The shafts of the proposed gears would be made from multiwalled carbon nanotubes. The gear teeth would be rigid molecules (typically, benzyne molecules), bonded to the nanotube shafts at atomically precise positions. For fabrication, it may be possible to position the molecular teeth by use of scanning tunneling microscopy (STM) or other related techniques. The capability to position individual organic molecules at room temperature by use of an STM tip has already been demonstrated. Routes to the chemical synthesis of carbon-nanotube-based gears are also under investigation. Chemical and physical aspects of the synthesis of molecular scale gears based on carbon nanotubes and related molecules, and dynamical properties of nanotube- based gears, have been investigated by computational simulations using established methods of quantum chemistry and molecular dynamics. Several particularly interesting and useful conclusions have been drawn from the dynamical simulations performed thus far: The forces acting on the gears would be more sensitive to local molecular motions than to gross mechanical motions of the overall gears. Although no breakage of teeth or of chemical bonds is expected at temperatures up to at least 3,000 K, the gears would not work well at temperatures above a critical range from about 600 to about 1,000 K. Gear temperature could probably be controlled by

  14. Computerized Design and Generation of Low-noise Helical Gears with Modified Surface Topology

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Chen, N. X.; Lu, J.; Handschuh, R. F.

    1994-01-01

    An approach for design and generation of low-noise helical gears with localized bearing contact is proposed. The approach is applied to double circular arc helical gears and modified involute helical gears. The reduction of noise and vibration is achieved by application of a predesigned parabolic function of transmission errors that is able to absorb a discontinuous linear function of transmission errors caused by misalignment. The localization of the bearing contact is achieved by the mismatch of pinion-gear tooth surfaces. Computerized simulation of meshing and contact of the designed gears demonstrated that the proposed approach will produce a pair of gears that has a parabolic transmission error function even when misalignment is present. Numerical examples for illustration of the developed approach are given.

  15. Precise low cost chain gears for heliostats

    NASA Astrophysics Data System (ADS)

    Liedke, Phillip; Lewandowski, Arkadiusz; Pfahl, Andreas; Hölle, Erwin

    2016-05-01

    This work investigates the potential of chain gears as precise and low cost driving systems for rim drive heliostats. After explaining chain gear basics the polygon effect and chain lengthening are investigated. The polygon effect could be measured by a heliostat with chain rim gear and the chain lengthening with an accordant test set up. Two gear stages are scope of this work: a rim gear and an intermediate gear. Dimensioning, pretensioning and designing for both stages are explained.

  16. High Pressure Angle Gears: Comparison to Typical Gear Designs

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Zabrajsek, Andrew J.

    2010-01-01

    A preliminary study has been completed to determine the feasibility of using high-pressure angle gears in aeronautic and space applications. Tests were conducted in the NASA Glenn Research Center (GRC) Spur Gear Test Facility at speeds up to 10,000 rpm and 73 N*m (648 in.*lb) for 3.18, 2.12, and 1.59 module gears (8, 12, and 16 diametral pitch gears), all designed to operate in the same test facility. The 3.18 module (8-diametral pitch), 28 tooth, 20deg pressure angle gears are the GRC baseline test specimen. Also, 2.12 module (12-diametral pitch), 42 tooth, 25deg pressure angle gears were tested. Finally 1.59 module (16-diametral pitch), 56 tooth, 35deg pressure angle gears were tested. The high-pressure angle gears were the most efficient when operated in the high-speed aerospace mode (10,000 rpm, lubricated with a synthetic turbine engine oil), and produced the lowest wear rates when tested with a perfluoroether-based grease. The grease tests were conducted at 150 rpm and 71 N*m (630 in.*lb).

  17. 50 CFR 665.427 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Archipelago Fisheries § 665.427 Allowable gear and gear restrictions. (a) Mariana coral reef ecosystem MUS may... vehicles/submersibles. (b) Mariana coral reef ecosystem MUS may not be taken by means of poisons... subpart who is established to be fishing for Mariana coral reef ecosystem MUS in the management area...

  18. 50 CFR 665.227 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Fisheries § 665.227 Allowable gear and gear restrictions. (a) Hawaii coral reef ecosystem MUS may be taken.../submersibles. (b) Hawaii coral reef ecosystem MUS may not be taken by means of poisons, explosives, or... established to be fishing for Hawaii coral reef ecosystem MUS in the Hawaii management area is prohibited....

  19. 50 CFR 665.127 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Fisheries § 665.127 Allowable gear and gear restrictions. (a) American Samoa coral reef ecosystem MUS may be.../submersibles. (b) American Samoa coral reef ecosystem MUS may not be taken by means of poisons, explosives, or... established to be fishing for coral reef ecosystem MUS in the management area is prohibited. (c) Existing...

  20. 50 CFR 665.127 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Fisheries § 665.127 Allowable gear and gear restrictions. (a) American Samoa coral reef ecosystem MUS may be.../submersibles. (b) American Samoa coral reef ecosystem MUS may not be taken by means of poisons, explosives, or... established to be fishing for coral reef ecosystem MUS in the management area is prohibited. (c) Existing...

  1. 50 CFR 665.427 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Archipelago Fisheries § 665.427 Allowable gear and gear restrictions. (a) Mariana coral reef ecosystem MUS may... vehicles/submersibles. (b) Mariana coral reef ecosystem MUS may not be taken by means of poisons... subpart who is established to be fishing for Mariana coral reef ecosystem MUS in the management area...

  2. 50 CFR 665.427 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Archipelago Fisheries § 665.427 Allowable gear and gear restrictions. (a) Mariana coral reef ecosystem MUS may... vehicles/submersibles. (b) Mariana coral reef ecosystem MUS may not be taken by means of poisons... subpart who is established to be fishing for Mariana coral reef ecosystem MUS in the management area...

  3. 50 CFR 665.427 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Archipelago Fisheries § 665.427 Allowable gear and gear restrictions. (a) Mariana coral reef ecosystem MUS may... vehicles/submersibles. (b) Mariana coral reef ecosystem MUS may not be taken by means of poisons... subpart who is established to be fishing for Mariana coral reef ecosystem MUS in the management area...

  4. 50 CFR 665.227 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Fisheries § 665.227 Allowable gear and gear restrictions. (a) Hawaii coral reef ecosystem MUS may be taken.../submersibles. (b) Hawaii coral reef ecosystem MUS may not be taken by means of poisons, explosives, or... established to be fishing for Hawaii coral reef ecosystem MUS in the Hawaii management area is prohibited....

  5. 50 CFR 665.227 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Fisheries § 665.227 Allowable gear and gear restrictions. (a) Hawaii coral reef ecosystem MUS may be taken.../submersibles. (b) Hawaii coral reef ecosystem MUS may not be taken by means of poisons, explosives, or... established to be fishing for Hawaii coral reef ecosystem MUS in the Hawaii management area is prohibited....

  6. 50 CFR 665.227 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Fisheries § 665.227 Allowable gear and gear restrictions. (a) Hawaii coral reef ecosystem MUS may be taken.../submersibles. (b) Hawaii coral reef ecosystem MUS may not be taken by means of poisons, explosives, or... established to be fishing for Hawaii coral reef ecosystem MUS in the Hawaii management area is prohibited....

  7. 50 CFR 665.127 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Fisheries § 665.127 Allowable gear and gear restrictions. (a) American Samoa coral reef ecosystem MUS may be.../submersibles. (b) American Samoa coral reef ecosystem MUS may not be taken by means of poisons, explosives, or... established to be fishing for coral reef ecosystem MUS in the management area is prohibited. (c) Existing...

  8. 50 CFR 665.127 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Fisheries § 665.127 Allowable gear and gear restrictions. (a) American Samoa coral reef ecosystem MUS may be.../submersibles. (b) American Samoa coral reef ecosystem MUS may not be taken by means of poisons, explosives, or... established to be fishing for coral reef ecosystem MUS in the management area is prohibited. (c) Existing...

  9. 50 CFR 665.427 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Archipelago Fisheries § 665.427 Allowable gear and gear restrictions. (a) Mariana coral reef ecosystem MUS may... vehicles/submersibles. (b) Mariana coral reef ecosystem MUS may not be taken by means of poisons... subpart who is established to be fishing for Mariana coral reef ecosystem MUS in the management area...

  10. 50 CFR 665.127 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Fisheries § 665.127 Allowable gear and gear restrictions. (a) American Samoa coral reef ecosystem MUS may be.../submersibles. (b) American Samoa coral reef ecosystem MUS may not be taken by means of poisons, explosives, or... established to be fishing for coral reef ecosystem MUS in the management area is prohibited. (c) Existing...

  11. 50 CFR 665.227 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Fisheries § 665.227 Allowable gear and gear restrictions. (a) Hawaii coral reef ecosystem MUS may be taken.../submersibles. (b) Hawaii coral reef ecosystem MUS may not be taken by means of poisons, explosives, or... established to be fishing for Hawaii coral reef ecosystem MUS in the Hawaii management area is prohibited....

  12. 50 CFR 665.627 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Island Area Fisheries § 665.627 Allowable gear and gear restrictions. (a) Coral reef ecosystem MUS may be...) Hand net/dip net; (5) Hoop net for Kona crab; (6) Throw net; (7) Barrier net; (8) Surround/purse net....) in the U.S. EEZ waters around Howland Island, Baker Island, Jarvis Island, Wake Island, Kingman...

  13. 50 CFR 665.627 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Island Area Fisheries § 665.627 Allowable gear and gear restrictions. (a) Coral reef ecosystem MUS may be...) Hand net/dip net; (5) Hoop net for Kona crab; (6) Throw net; (7) Barrier net; (8) Surround/purse net....) in the U.S. EEZ waters around Howland Island, Baker Island, Jarvis Island, Wake Island, Kingman...

  14. 50 CFR 665.627 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Island Area Fisheries § 665.627 Allowable gear and gear restrictions. (a) Coral reef ecosystem MUS may be...) Hand net/dip net; (5) Hoop net for Kona crab; (6) Throw net; (7) Barrier net; (8) Surround/purse net....) in the U.S. EEZ waters around Howland Island, Baker Island, Jarvis Island, Wake Island, Kingman...

  15. 50 CFR 665.627 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Island Area Fisheries § 665.627 Allowable gear and gear restrictions. (a) Coral reef ecosystem MUS may be...) Hand net/dip net; (5) Hoop net for Kona crab; (6) Throw net; (7) Barrier net; (8) Surround/purse net....) in the U.S. EEZ waters around Howland Island, Baker Island, Jarvis Island, Wake Island, Kingman...

  16. 50 CFR 665.627 - Allowable gear and gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Island Area Fisheries § 665.627 Allowable gear and gear restrictions. (a) Coral reef ecosystem MUS may be...) Hand net/dip net; (5) Hoop net for Kona crab; (6) Throw net; (7) Barrier net; (8) Surround/purse net....) in the U.S. EEZ waters around Howland Island, Baker Island, Jarvis Island, Wake Island, Kingman...

  17. Double Helical Gear Performance Results in High Speed Gear Trains

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Ehinger, Ryan; Sinusas, Eric; Kilmain, Charles

    2010-01-01

    The operation of high speed gearing systems in the transmissions of tiltrotor aircraft has an effect on overall propulsion system efficiency. Recent work has focused on many aspects of high-speed helical gear trains as would be used in tiltrotor aircraft such as operational characteristics, comparison of analytical predictions to experimental data and the affect of superfinishing on transmission performance. Baseline tests of an aerospace quality system have been conducted in the NASA Glenn High-Speed Helical Gear Train Test Facility and have been described in earlier studies. These earlier tests had utilized single helical gears. The results that will be described in this study are those attained using double helical gears. This type of gear mesh can be configured in this facility to either pump the air-oil environment from the center gap between the meshing gears to the outside of tooth ends or in the reverse direction. Tests were conducted with both inward and outward air-oil pumping directions. Results are compared to the earlier baseline results of single helical gears.

  18. Double Helical Gear Performance Results in High Speed Gear Trains

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Ehinger, Ryan; Sinusas, Eric; Kilmain, Charles

    2009-01-01

    The operation of high speed gearing systems in the transmissions of tiltrotor aircraft has an effect on overall propulsion system efficiency. Recent work has focused on many aspects of high-speed helical gear trains as would be used in tiltrotor aircraft such as operational characteristics, comparison of analytical predictions to experimental data and the affect of superfinishing on transmission performance. Baseline tests of an aerospace quality system have been conducted in the NASA Glenn High-Speed Helical Gear Train Test Facility and have been described in earlier studies. These earlier tests had utilized single helical gears. The results that will be described in this study are those attained using double helical gears. This type of gear mesh can be configured in this facility to either pump the air-oil environment from the center gap between the meshing gears to the outside of tooth ends or in the reverse direction. Tests were conducted with both inward and outward air-oil pumping directions. Results are compared to the earlier baseline results of single helical gears.

  19. Micro cycloid-gear system fabricated by multiexposure LIGA technique

    NASA Astrophysics Data System (ADS)

    Hirata, Toru; Chung, Song-Jo; Hein, Herbert; Akashi, Tomoyuki; Mohr, Juergen

    1999-09-01

    In this paper, a prototype of 2 mm-diameter micro-cycloid gear system fabricated by the multi-exposure LIGA technique is presented. The entire gear system consists of a casing and three vertically stacked disks and gears. Each part is composed of three different levels. The first level, 40 micrometers high, was fabricated by UV-lithography, and the second as well as the third level, 195 micrometers and 250 micrometers high respectively, were processed by aligned deep X-ray lithography (DXL). The alignment error between two DXL- processed layers was measured, and the results have turned out to be within +/- 5 micrometers range. As a result of the height control process by the mechanical surface machining, the deviation of structural height has been maintained within +/- 3 micrometers range for the UV-lithography-processed structures, and +/- 10 micrometers for the DXL-processed structures. Further the tests of gear assembly were implemented with 125 micrometers -diameter glass fiber, by using a die-bonding machine with vacuum gripper under stereo- microscope. Finally the dynamic tests of the gear system were successfully conducted with the mechanical torque input by an electrical motor. A proper rotational speed reduction was observed in the operational input range of 3 to 1500 rpm with the designed gear ratio of 18.

  20. Planetary gear train for automatic transmission

    SciTech Connect

    Hiraiwa, K.

    1987-03-31

    A planetary gear train is described comprising: a first planetary gear set having rotary elements including a first sun gear, a first ring gear and a first pinion carrier rotatably supporting a plurality of first pinions meshing with the first sun gear and the first ring gear; a second planetary gear set having rotary elements including a second sun gear, a second ring gear and a second pinion carrier rotatably supporting a plurality of second pinions meshing with the second sun gear and the second ring gear; an input shaft drivingly-connected with the first ring gear; an output shaft; first drive connection establishing means for connecting the second ring gear with the output shaft; the first drive connection establishing means comprising: a third planetary gear set including a third sun gear constantly connected with the second ring gear, a third ring gear, and a third pinion carrier constantly connected with the output shaft. The third pinion carrier rotatably supports third pinions meshing with the third sun and ring gears.

  1. Materials for helicopter gears

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Some of the power train transmission gears in helicopter drive systems can become critical components as performance requirements are increased; accordingly, increasing attention must be paid to new alloys in order to obtain required performance reliability and survivability. Candidate advanced alloys, with improved high temperature properties, while increasing the resistance to scoring and scuffing, tend to have lower ductility and fracture toughness. An attempt is made to identify design materials, and process problems and requirements. In addition, it is recommended that the characterization of candidate steels be accelerated; preliminary investigation indicates that new alloys may provide improved capability against surface distress.

  2. Gear Design Effects on the Performance of High Speed Helical Gear Trains as Used in Aerospace Drive Systems

    NASA Technical Reports Server (NTRS)

    Handschuh, R.; Kilmain, D.; Ehinger, R.; Sinusas, E.

    2013-01-01

    The performance of high-speed helical gear trains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction/torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High Speed Helical Gear Train Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160 to 250 F) and lubricating jet pressure (60 to 80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears. The empirical data resulting from this study will be useful to the design of future helical gear train systems anticipated for next generation rotorcraft drive systems.

  3. Gear Design Effects on the Performance of High Speed Helical Gear Trains as Used in Aerospace Drive Systems

    NASA Technical Reports Server (NTRS)

    Handschuh, R.; Kilmain, C.; Ehinger, R.; Sinusas, E.

    2013-01-01

    The performance of high-speed helical gear trains is of particular importance for tiltrotor aircraft drive systems. These drive systems are used to provide speed reduction / torque multiplication from the gas turbine output shaft and provide the necessary offset between these parallel shafts in the aircraft. Four different design configurations have been tested in the NASA Glenn Research Center, High Speed Helical Gear Train Test Facility. The design configurations included the current aircraft design, current design with isotropic superfinished gear surfaces, double helical design (inward and outward pumping), increased pitch (finer teeth), and an increased helix angle. All designs were tested at multiple input shaft speeds (up to 15,000 rpm) and applied power (up to 5,000 hp). Also two lubrication, system-related, variables were tested: oil inlet temperature (160 to 250 degF) and lubricating jet pressure (60 to 80 psig). Experimental data recorded from these tests included power loss of the helical system under study, the temperature increase of the lubricant from inlet to outlet of the drive system and fling off temperatures (radially and axially). Also, all gear systems were tested with and without shrouds around the gears. The empirical data resulting from this study will be useful to the design of future helical gear train systems anticipated for next generation rotorcraft drive systems.

  4. Gears and Power Transmission Systems for Helicopters and Turboprops; Conference Proceedings: Propulsion and Energetics Panel Symposium (64th) Held at Lisbon, Portugal on 8-12 October 1984.

    DTIC Science & Technology

    1985-01-01

    double row bearings are used in planetary gear supports for their ability to withstand misalignments imposed by offset loads on the planet carrier...13 a similar study was done for a typical planetary gear set such as found in a turboprop or helicopter reduction gear stage. The study was done for...in a single stage are not common. The order of weights from lightest to heaviest (for equal gear ratios) is planetary , parallel axis, spiral bevel

  5. Torque-Splitting Gear Drive

    NASA Technical Reports Server (NTRS)

    Kish, J.

    1991-01-01

    Geared drive train transmits torque from input shaft in equal parts along two paths in parallel, then combines torques in single output shaft. Scheme reduces load on teeth of meshing gears while furnishing redundancy to protect against failures. Such splitting and recombination of torques common in design of turbine engines.

  6. Investigating Vibration Properties of a Planetary Gear Set with a Cracked Tooth in a Planet Gear

    DTIC Science & Technology

    2014-12-23

    Investigating Vibration Properties of a Planetary Gear Set with a Cracked Tooth in a Planet Gear Xihui Liang 1 and Ming J. Zuo 2 1,2...rotation of the carrier. To facilitate fault detection of a planetary gearbox and avoid catastrophic consequences caused by gear failures, it is...properties of a planetary gear set when there is a cracked tooth in a planet gear . Displacement signals of the sun gear and the planet gear , and

  7. Monolithic geared-mechanisms driven by a polysilicon surface-micromachined on-chip electrostatic microengine

    SciTech Connect

    Sniegowski, J.J.; Miller, S.L.; LaVigne, G.F.; Rodgers, M.S.; McWhorter, P.J.

    1996-05-01

    We have previously described a practical micromachined power source: the polysilicon, surface-micromachined, electrostatically actuated microengine. Here we report on 3 aspects of implementing the microengine. First, we discuss demonstrations of the first-generation microengine actuating geared micromechanisms including gear trains with elements having dimensions comparable to the drive gear (about 50 {mu}m) and a relatively large (1600-{mu}m-diameter) rotating optical shutter element. These configurations span expected operating extremes for the microengine and address the coupling and loading issues for very-low-aspect-ratio micromechanisms which are common to the design of surface-micromachined devices. Second, we report on a second-generation of designs that utilize improved gear teeth design, a gear speed-reduction unit, and higher force-per-unit-area electrostatic comb drives. The speed-reduction unit produces an overall angular speed reduction of 9.63 and requires dual-level compound gears. Third, we discuss a dynamics model developed to accomplish 3 objectives: drive inertial loads in a controlled fashion, minimize stress and frictional forces during operation, and determine as a function of time the forces associated with the drive gear (eg load torque on drive gear from friction).

  8. Installing and maintaining gear pumps

    SciTech Connect

    Whitmire, K.

    1996-03-01

    While not as common as centrifugal pumps in the CPI, gear pumps play important roles in handling many of today`s more difficult-to-pump fluids. Because they operate at lower speeds -- generally, 900 rpm or less -- their seals and bearings tend to last longer than those of centrifugal models. In addition, unlike centrifugal pumps, gear pumps` flows are independent of their systems` pressure curves, and they can handle a wider range of viscosities. Although high-flow, low-head applications remain the domain of centrifugal pumps, the use of gear pumps is increasing in the chemical process industries (CPI). While some application boundaries between gears and centrifugals are blurring, there are some crucial differences between the way the two are operated and maintained -- for example, where pressure relief is concerned. This article provides a general summary of gear pump characteristics and applications, highlighting critical aspects of installation, operation and maintenance.

  9. Transmission error and load distribution analysis of spur and double helical gear pairs used in a split path helicopter transmission design

    NASA Astrophysics Data System (ADS)

    Hochmann, David; Houser, Donald R.; Thomas, Jacob

    1991-05-01

    Because the reduction of gear noise in next-generation rotorcraft depends on the reduction of transmission errors, attention is presently given to the prediction of such errors and the load distributions of both a spur-gear pair and a double helical gear train used in a split-path helicopter transmission. Two cases are examined: (1) the spur gear mesh between the spur shaft and the lower spur/helical shaft, and (2) the double helical gear mesh between the lower spur/helical shaft and the output bull bear shaft.

  10. Maximum life spiral bevel reduction design

    NASA Technical Reports Server (NTRS)

    Savage, M.; Prasanna, M. G.; Coe, H. H.

    1992-01-01

    Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ratio under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed backcone distance of the spiral bevel gear set for a specified speed reduction, shaft angle, input torque, and power. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.

  11. Maximum life spiral bevel reduction design

    NASA Astrophysics Data System (ADS)

    Savage, M.; Prasanna, M. G.; Coe, H. H.

    1992-07-01

    Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ratio under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed backcone distance of the spiral bevel gear set for a specified speed reduction, shaft angle, input torque, and power. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.

  12. Dynamic gearing in running dogs.

    PubMed

    Carrier, D R; Gregersen, C S; Silverton, N A

    1998-12-01

    Dynamic gearing is a mechanism that has been suggested to enhance the performance of skeletal muscles by maintaining them at the shortening velocities that maximize their power or efficiency. We investigated this hypothesis in three domestic dogs during trotting and galloping. We used ground force recordings and kinematic analysis to calculate the changes in gear ratio that occur during the production of the external work of locomotion. We also monitored length changes of the vastus lateralis muscle, an extensor muscle of the knee, using sonomicrometry in four additional dogs to determine the nature and rate of active shortening of this muscle. During both trotting and galloping, the gear ratios of the extensor muscles of the elbow, wrist and ankle joints were relatively constant early in limb support, but decreased rapidly during the second half of support. The gear ratio at the hip exerted an extensor moment initially, but decreased throughout limb support and became negative midway through support. This pattern of decreasing gear ratio during the second half of support indicates that dynamic gearing does not maximize muscle power or efficiency at the elbow, wrist, hip and ankle joints. In contrast, the extensor muscles of the shoulder and knee joints exhibited an increase in gear ratio during limb support. In two dogs, the vastus lateralis muscle shortened at a relatively constant rate of 3.7-4 lengths s-1 during intermediate-speed galloping. This pattern of increasing gear ratio and constant velocity of muscle shortening at the knee joint is consistent with the hypothesis of dynamic gearing. Given the amount of work done at the knee and shoulder joints of running dogs, dynamic gearing may contribute to the economy of constant-speed running and may be important to integrated limb function.

  13. Improved Gear Shapes for Face Worm Gear Drives

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Nava, Alessandro; Fan, Qi; Fuentes, Alfonso

    2005-01-01

    Shapes different from the traditional ones have been proposed for face worm gears and for conical and cylindrical worms that mesh with them. The proposed shapes are based on the concept of generating a face worm gear surface by use of a tilted head cutter instead of by the traditional use of a hob. (As used here, head cutter is also meant to signify, alternatively, a head grinding tool.) The gear-surface-generation equipment would be similar to that used for generation of spiral bevel and hypoid gears. In comparison with the corresponding traditional hob, a tilted head cutter according to the proposal would be larger, could be fabricated with greater precision, and would enable the generation of gear surfaces with greater precision and greater productivity. A face worm gear would be generated (see figure) by use of a tilted head cutter, the blades or grinding surfaces of which would have straight-line profiles. The tilt of the head cutter would prevent interference with teeth adjacent to the groove being cut or ground. A worm to mesh with the face worm gear would be generated by use of a tilted head cutter mounted on the cradle of a generating machine. The blades or grinding surfaces of the head cutter would have a parabolic profile and would deviate from the straight-line profiles of the head cutter for the face worm gear. The shortest distance between the worm and the cradle would follow a parabolic function during the cycle of meshing in the generating process to provide a parabolic function of transmission errors to the gear drive. The small mismatch between the profiles of the face-worm-gear and worm head cutters would make it possible to localize the bearing contact in the worm gear drive. The parabolic function of transmission errors could absorb discontinuous linear functions of transmission errors caused by errors of alignment; this could afford a significant benefit, in that such errors are main sources of noise and vibration in gear drives. The main

  14. 50 CFR 648.84 - Gear-marking requirements and gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Gear-marking requirements and gear... Management Measures for the NE Multispecies and Monkfish Fisheries § 648.84 Gear-marking requirements and gear restrictions. (a) Bottom-tending fixed gear, including, but not limited to, gillnets and...

  15. 50 CFR 648.84 - Gear-marking requirements and gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Gear-marking requirements and gear... Management Measures for the NE Multispecies and Monkfish Fisheries § 648.84 Gear-marking requirements and gear restrictions. (a) Bottom-tending fixed gear, including, but not limited to, gillnets and...

  16. 50 CFR 648.84 - Gear-marking requirements and gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear-marking requirements and gear... Management Measures for the NE Multispecies and Monkfish Fisheries § 648.84 Gear-marking requirements and gear restrictions. (a) Bottom-tending fixed gear, including, but not limited to, gillnets and...

  17. 50 CFR 648.84 - Gear-marking requirements and gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Gear-marking requirements and gear... Management Measures for the NE Multispecies and Monkfish Fisheries § 648.84 Gear-marking requirements and gear restrictions. (a) Bottom-tending fixed gear, including, but not limited to, gillnets and...

  18. Gear shift controller for automatic transmission

    SciTech Connect

    Nishikawa, M.; Sakai, S.; Sakurai, T.

    1987-01-20

    A gear shift controller is described for an automatic transmission having a gear shift, comprising: a hydraulic torque converter; a gear change group, having a plurality of gears, each gear providing a different transmission ratio for the transmission of power from the hydraulic torque converter to the output of the transmission, each of the gears comprising a gear train; a one-way clutch interposed in at least one of the gear trains; a plurality of clutch means operatively connected with the gear trains for actuating each of the gear trains selectively; a gear change determination circuit operatively connected with the clutch means to control the operation of each of the clutch means according to a predetermined gear shifting program for engaging a gear train selected by the program; a coasting detection circuit for detecting a car in the coasting state; a gear shift limiting circuit, operatively connected with the gear change determination circuit and with the coasting detection circuit. The circuit is for actuating only the gear train in which the one-way clutch is interposed immediately, regardless of the selected gear train and of the operation of the gear change determination circuit, when the coasting detection circuit has determined the car to be coasting; and an operation transfer control system including a brake operation detecting means and a mode selector switch means for transferring the operation of the gear shift limiting circuit. The operation transfer control system is adapted to stop, upon detection of one of the brake operation and a reset state of the mode selector switch, the operation of the gear shift limiting circuit and to place the plurality of clutch means under the control of the gear change determination circuit.

  19. Computerized Inspection Of Gear-Tooth Surfaces

    NASA Technical Reports Server (NTRS)

    Handschuh, R. F.; Litvin, F. L.; Zhang, Y.; Kuan, C.

    1994-01-01

    Method of manufacturing gears with precisely shaped teeth involves computerized inspection of gear-tooth surfaces followed by adjustments of machine-tool settings to minimize deviations between real and theoretical versions of surfaces. Thus, iterated cycles of cutting gear teeth, inspection, and adjustments help increase and/or maintain precision of subsequently manufactured gears.

  20. 29 CFR 1918.54 - Rigging gear.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Rigging gear. 1918.54 Section 1918.54 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Vessel's Cargo Handling Gear § 1918.54 Rigging gear. (a... other alternate device shall be provided to allow trimming of the gear and to prevent employees...

  1. 29 CFR 1918.54 - Rigging gear.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Rigging gear. 1918.54 Section 1918.54 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Vessel's Cargo Handling Gear § 1918.54 Rigging gear. (a... other alternate device shall be provided to allow trimming of the gear and to prevent employees...

  2. 29 CFR 1918.54 - Rigging gear.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Rigging gear. 1918.54 Section 1918.54 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Vessel's Cargo Handling Gear § 1918.54 Rigging gear. (a... other alternate device shall be provided to allow trimming of the gear and to prevent employees...

  3. 29 CFR 1918.54 - Rigging gear.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Rigging gear. 1918.54 Section 1918.54 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Vessel's Cargo Handling Gear § 1918.54 Rigging gear. (a... other alternate device shall be provided to allow trimming of the gear and to prevent employees...

  4. 50 CFR 622.248 - Authorized gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Authorized gear. 622.248 Section 622.248... the South Atlantic Region § 622.248 Authorized gear. (a) Traps. Traps are the only fishing gear... Atlantic EEZ may not be retained on board a vessel possessing or using unauthorized gear. (b) Buoy line...

  5. 50 CFR 648.203 - Gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 648.203 Section 648.203... Herring Fishery § 648.203 Gear restrictions. (a) Midwater trawl gear may only be used by a vessel issued a... Lightship Area as described in § 648.81(c)(1), provided it complies with the midwater trawl gear...

  6. 50 CFR 622.248 - Authorized gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Authorized gear. 622.248 Section 622.248... the South Atlantic Region § 622.248 Authorized gear. (a) Traps. Traps are the only fishing gear... Atlantic EEZ may not be retained on board a vessel possessing or using unauthorized gear. (b) Buoy line...

  7. 29 CFR 1918.54 - Rigging gear.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Rigging gear. 1918.54 Section 1918.54 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR LONGSHORING Vessel's Cargo Handling Gear § 1918.54 Rigging gear. (a... other alternate device shall be provided to allow trimming of the gear and to prevent employees...

  8. Variable gearing in pennate muscles.

    PubMed

    Azizi, Emanuel; Brainerd, Elizabeth L; Roberts, Thomas J

    2008-02-05

    Muscle fiber architecture, i.e., the physical arrangement of fibers within a muscle, is an important determinant of a muscle's mechanical function. In pennate muscles, fibers are oriented at an angle to the muscle's line of action and rotate as they shorten, becoming more oblique such that the fraction of force directed along the muscle's line of action decreases throughout a contraction. Fiber rotation decreases a muscle's output force but increases output velocity by allowing the muscle to function at a higher gear ratio (muscle velocity/fiber velocity). The magnitude of fiber rotation, and therefore gear ratio, depends on how the muscle changes shape in the dimensions orthogonal to the muscle's line of action. Here, we show that gear ratio is not fixed for a given muscle but decreases significantly with the force of contraction (P < 0.0001). We find that dynamic muscle-shape changes promote fiber rotation at low forces and resist fiber rotation at high forces. As a result, gearing varies automatically with the load, to favor velocity output during low-load contractions and force output for contractions against high loads. Therefore, muscle-shape changes act as an automatic transmission system allowing a pennate muscle to shift from a high gear during rapid contractions to low gear during forceful contractions. These results suggest that variable gearing in pennate muscles provides a mechanism to modulate muscle performance during mechanically diverse functions.

  9. Numerical Simulation Of Cutting Of Gear Teeth

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.; Huston, Ronald L.; Mavriplis, Dimitrios

    1994-01-01

    Shapes of gear teeth produced by gear cutters of specified shape simulated computationally, according to approach based on principles of differential geometry. Results of computer simulation displayed as computer graphics and/or used in analyses of design, manufacturing, and performance of gears. Applicable to both standard and non-standard gear-tooth forms. Accelerates and facilitates analysis of alternative designs of gears and cutters. Simulation extended to study generation of surfaces other than gears. Applied to cams, bearings, and surfaces of arbitrary rolling elements as well as to gears. Possible to develop analogous procedures for simulating manufacture of skin surfaces like automobile fenders, airfoils, and ship hulls.

  10. Bearing, gearing, and lubrication technology

    NASA Technical Reports Server (NTRS)

    Anderson, W. J.

    1978-01-01

    Results of selected NASA research programs on rolling-element and fluid-film bearings, gears, and elastohydrodynamic lubrication are reported. Advances in rolling-element bearing material technology, which have resulted in a significant improvement in fatigue life, and which make possible new applications for rolling bearings, are discussed. Research on whirl-resistant, fluid-film bearings, suitable for very high-speed applications, is discussed. An improved method for predicting gear pitting life is reported. An improved formula for calculating the thickness of elastohydrodynamic films (the existence of which help to define the operating regime of concentrated contact mechanisms such as bearings, gears, and cams) is described.

  11. Cogging Torque Characteristics of a Magnetic-Geared Motor

    NASA Astrophysics Data System (ADS)

    Niguchi, Noboru; Hirata, Katsuhiro

    This paper describes the cogging torque characteristics of a magnetic-geared motor with permanent magnets only on the high-speed rotor. The operational principle, which is different from that of the magnetic-geared motor with permanent magnets on the high-speed rotor and stator, is described. The torque characteristics, especially the order of the cogging torque, are mathematically formulated and verified by conducting 3-D finite element analysis and carrying out measurements on a prototype. Furthermore, a novel cogging torque reduction method is proposed and verified as well.

  12. Enhanced Automated Spiral Bevel Gear Inspection

    DTIC Science & Technology

    1992-03-01

    in excessive wear, scoring, or even tooth breakage. This is as true for spiral bevel gears as it is for spur and helical gears. The elemental...conformity inspection of tooth profiles that is commonly performed on spur and helical gears, however, is not practical for spiral bevel gears because the size...AD-A250 770 NASA AVSCOM Contractor Report 189125 Technical Report 91-C-048 Enhanced Automated Spiral Bevel Gear Inspection DTIC Harold K. Frint and

  13. The application of manufacturing systems engineering for aero engine gears

    NASA Astrophysics Data System (ADS)

    Pewsey, Stephen M. S.

    1991-10-01

    The adoption of manufacturing systems engineering principles in order to improve cost effectiveness of manufacturing operations is considered. The introduction of cells where families of parts are made from raw material to finished product using a team approach has been initiated. The benefits to date are significant in terms of lead time reductions, inventory, and nonconformance savings as well as improvements in work force motivation and morale. The overall corporate manufacturing strategy of gears is explained. Some of the problems encountered with the transfer of gear production from one site to another with minimum disruption are described. Some of the radical changes being made in the manufacture of gears in line with the strategy of making Rolls-Royce a total quality organization are also described.

  14. LSRA with Shuttle main gear

    NASA Technical Reports Server (NTRS)

    1993-01-01

    A space shuttle landing gear system is visible between the two main landing gear components on this NASA CV-990, modified as a Landing Systems Research Aircraft (LSRA). The space shuttle landing gear test unit, operated by a high-pressure hydraulic system, allowed engineers to assess and document the performance of space shuttle main and nose landing gear systems, tires and wheel assemblies, plus braking and nose wheel steering performance. The series of 155 test missions for the space shuttle program, conducted at NASA's Dryden Flight Research Center, Edwards, California, provided extensive data about the life and endurance of the shuttle tire systems and helped raise the shuttle crosswind landing limits at Kennedy.

  15. Investigation of Dynamic Force/Vibration Transmission Characteristics of Four-Square Type Gear Durability Test Machines

    NASA Technical Reports Server (NTRS)

    Kahraman, Ahmet

    2002-01-01

    In this study, design requirements for a dynamically viable, four-square type gear test machine are investigated. Variations of four-square type gear test machines have been in use for durability and dynamics testing of both parallel- and cross-axis gear set. The basic layout of these machines is illustrated. The test rig is formed by two gear pairs, of the same reduction ratio, a test gear pair and a reaction gear pair, connected to each other through shafts of certain torsional flexibility to form an efficient, closed-loop system. A desired level of constant torque is input to the circuit through mechanical (a split coupling with a torque arm) or hydraulic (a hydraulic actuator) means. The system is then driven at any desired speed by a small DC motor. The main task in hand is the isolation of the test gear pair from the reaction gear pair under dynamic conditions. Any disturbances originated at the reaction gear mesh might potentially travel to the test gearbox, altering the dynamic loading conditions of the test gear mesh, and hence, influencing the outcome of the durability or dynamics test. Therefore, a proper design of connecting structures becomes a major priority. Also, equally important is the issue of how close the operating speed of the machine is to the resonant frequencies of the gear meshes. This study focuses on a detailed analysis of the current NASA Glenn Research Center gear pitting test machine for evaluation of its resonance and vibration isolation characteristics. A number of these machines as the one illustrated has been used over last 30 years to establish an extensive database regarding the influence of the gear materials, processes surface treatments and lubricants on gear durability. This study is intended to guide an optimum design of next generation test machines for the most desirable dynamic characteristics.

  16. A study of the optimum configuration of injection molded plastic gear by modification of gear tooth

    NASA Astrophysics Data System (ADS)

    Lee, Dae-Suep; Kwon, Young-Doo; Doc, Jin-Uk; Leed, Jun-Hyuk

    2009-07-01

    In this study, the gear system is optimized by modifying the tooth configuration of the plastic gears. Plastic gear is widely used as a machine element in industries of electric and electronic parts, automotive parts etc. Unlike the steel gear, the plastic gear has low load- transmission, durability and reliability. On the other hand, it is light-weight, low-noise, operable without a lubricant, shock absorptive, and anti-corrosive. The gear characteristics are calculated and analyzed by Hexagon and FEM (Finite Element Method) tools, and the characteristics of the standard gear and the addendum modified gear of the steel gear and the plastic gear are compared. When torque is applied to these gear systems, the system using the addendum modified gear can realize soft contact between gears. So, the noise of the addendum modified gear system was less than that of the common normal gear system. However, this is not applicable to any material, such as steel which is governed by DIN (Deuteshe Industrie Norm) recommendation. This study adopted the narrow tip tooth plastic gear, and proposed the optimum addendum modified gear with respect to stress, noise and contact ratio. To calculate and analyze the simulation of gear matching, we used commercial tools like CATIA, Auto-CAD, MARC for simulation and Hexagon for calculation.

  17. Rotor instability due to a gear coupling connected to a bearingless sun wheel of a planetary gear

    NASA Technical Reports Server (NTRS)

    Buehlmann, E. T.; Luzi, A.

    1989-01-01

    A 21 MW electric power generating unit comprises a gas turbine, a planetary gear, and a generator connected together by gear couplings. For simplicity of the design and high performance the pinion of the gear has no bearing. It is centered by the planet wheels only. The original design showed a strong instability and a natural frequency increasing with the load between 2 and 6.5 MW. In this operating range the natural frequency was below the operating speed of the gas turbine, n sub PT = 7729 RPM. By shortening the pinion shaft and reduction of its moment of inertia the unstable natural frequency was shifted well above the operating speed. With that measure the unit now operates with stability in the entire load range.

  18. Generation and Computerized Simulation of Meshing and Contact of Modified Involute Helical Gears

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Chen, Ningxin; Lu, Jian

    1995-01-01

    The design and generation of modified involute helical gears that have a localized and stable bearing contact, and reduced noise and vibration characteristics are described. The localization of the bearing contact is achieved by the mismatch of the two generating surfaces that are used for generation of the pinion and the gear. The reduction of noise and vibration will be achieved by application of a parabolic function of transmission errors that is able to absorb the almost linear function of transmission errors caused by gear misalignment. The meshing and contact of misaligned gear drives can be analyzed by application of computer programs that have been developed. The computations confirmed the effectiveness of the proposed modification of the gear geometry. A numerical example that illustrates the developed theory is provided.

  19. 3-D finite element cyclic symmetric and contact stress analysis for a complete gear train

    NASA Astrophysics Data System (ADS)

    Yin, Zeyong; Xu, Youliang; Gao, Xiangqun; Wei, Gang

    1992-10-01

    A complete gear train of a reduction gearbox is the object of finite element stress analysis. One of the basic segments of the complete gear train is taken as the computational model in the light of the cyclic symmetry of the gear train; meanwhile, the contact transmission forces between the corresponding meshed teeth are considered in the analysis of the model. For simplicity, the corresponding meshed lines are used instead of the actual contact surfaces. Both torque and centrifugal loads are involved in the analysis. The stresses in all the parts of a complete gear train can be determined by one analysis. The computed results show that the contact force on a meshed tooth is correlative not only to the length of the meshed line, but also to its position. It is shown that the neglect of the stress resulted from centrifugal load is inappropriate to a high speed gear train.

  20. Gear shift control mechanism

    SciTech Connect

    Janson, D.A.

    1987-03-10

    A gear shift control mechanism is described comprising: multiple shift rods directed substantially parallel to one another, each rod carrying a shift fork for axial movement; a shift lever supported for pivotal movement about a first axis directed parallel to the axes of the shift rods and for pivotal movement about a second axis directed substantially perpendicular to the axes of the shift rods. The lever is moveable about the first axis and the second axis into engagement with a selected shift fork; interlock means located on each lateral side of the shift lever and mounted for pivotal movement about the first axis for blocking engagement with the shift forks; detent means for holding the shift lever in multiple predetermined angular positions about the second axis; and spring means located on a lateral side of the shift lever and mounted for pivotal movement about the first axis into interference contact with the shift forks for producing a force tending to resiliently bias the shift lever out of engagement with the selected shift fork.

  1. Molecular gearing systems

    SciTech Connect

    Gakh, Andrei A.; Sachleben, Richard A.; Bryan, Jeff C.

    1997-11-01

    The race to create smaller devices is fueling much of the research in electronics. The competition has intensified with the advent of microelectromechanical systems (MEMS), in which miniaturization is already reaching the dimensional limits imposed by physics of current lithographic techniques. Also, in the realm of biochemistry, evidence is accumulating that certain enzyme complexes are capable of very sophisticated modes of motion. Complex synergistic biochemical complexes driven by sophisticated biomechanical processes are quite common. Their biochemical functions are based on the interplay of mechanical and chemical processes, including allosteric effects. In addition, the complexity of this interplay far exceeds that of typical chemical reactions. Understanding the behavior of artificial molecular devices as well as complex natural molecular biomechanical systems is difficult. Fortunately, the problem can be successfully resolved by direct molecular engineering of simple molecular systems that can mimic desired mechanical or electronic devices. These molecular systems are called technomimetics (the name is derived, by analogy, from biomimetics). Several classes of molecular systems that can mimic mechanical, electronic, or other features of macroscopic devices have been successfully synthesized by conventional chemical methods during the past two decades. In this article we discuss only one class of such model devices: molecular gearing systems.

  2. Molecular gearing systems

    DOE PAGES

    Gakh, Andrei A.; Sachleben, Richard A.; Bryan, Jeff C.

    1997-11-01

    The race to create smaller devices is fueling much of the research in electronics. The competition has intensified with the advent of microelectromechanical systems (MEMS), in which miniaturization is already reaching the dimensional limits imposed by physics of current lithographic techniques. Also, in the realm of biochemistry, evidence is accumulating that certain enzyme complexes are capable of very sophisticated modes of motion. Complex synergistic biochemical complexes driven by sophisticated biomechanical processes are quite common. Their biochemical functions are based on the interplay of mechanical and chemical processes, including allosteric effects. In addition, the complexity of this interplay far exceeds thatmore » of typical chemical reactions. Understanding the behavior of artificial molecular devices as well as complex natural molecular biomechanical systems is difficult. Fortunately, the problem can be successfully resolved by direct molecular engineering of simple molecular systems that can mimic desired mechanical or electronic devices. These molecular systems are called technomimetics (the name is derived, by analogy, from biomimetics). Several classes of molecular systems that can mimic mechanical, electronic, or other features of macroscopic devices have been successfully synthesized by conventional chemical methods during the past two decades. In this article we discuss only one class of such model devices: molecular gearing systems.« less

  3. Flex-gear power transmission system for transmitting EMF between Sun and ring gears

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1994-01-01

    A plurality of flexible cylindrical members, termed flex-gears and having gear tooth type perimeters are located in an annular space between two concentric rotating gear members, one an inner gear member and the other an outer ring gear member, both of which have mutually facing toothed surfaces which engage the flex-gears. The flex-gears rotate and orbit around the annular space as planetary gears when the inner and outer gear members rotate with respect to one another. Pairs of these elements located in two mutually parallel planes and separated by insulators provide two electrical conductor paths across which an electrical signal source, AC or DC, can be connected and coupled to an electrical device. Alternatively, one set of elements including outer gears segmented into mutually insulated semicircles and inner gears segmented into mutually insulated quadrants can be used.

  4. Advanced Face Gear Surface Durability Evaluations

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Heath, Gregory F.

    2016-01-01

    The surface durability life of helical face gears and isotropic super-finished (ISF) face gears was investigated. Experimental fatigue tests were performed at the NASA Glenn Research Center. Endurance tests were performed on 10 sets of helical face gears in mesh with tapered involute helical pinions, and 10 sets of ISF-enhanced straight face gears in mesh with tapered involute spur pinions. The results were compared to previous tests on straight face gears. The life of the ISF configuration was slightly less than that of previous tests on straight face gears. The life of the ISF configuration was slightly greater than that of the helical configuration.

  5. Contact Stress of Modified Curvilinear Gears

    NASA Astrophysics Data System (ADS)

    Chen, Yi-Cheng; Gu, Ming-Lune

    2010-10-01

    The contact characteristics of a modified curvilinear gear set were investigated based on finite element analysis in this study. Firstly, the mathematical model of the modified curvilinear gears was developed based on the theory of gearing. Then a solid model of a modified curvilinear gear set was built by utilizing computer-aided design software. Finite element analysis enabled us to investigate the contact stress of a contact teeth pair. The variation and distribution of the contact stresses and bending stresses are also studied under different gear design parameters. Finally, illustrative examples were presented to demonstrate the contact characteristics of the modified curvilinear gears.

  6. 32. DETAIL VIEW OF PIVOT SPAN TURNTABLE, SHOWING MORTISE GEAR, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. DETAIL VIEW OF PIVOT SPAN TURNTABLE, SHOWING MORTISE GEAR, GEAR SHAFT, DRIVE GEAR AND BULL GEAR, LOOKING SOUTHEAST - Alton Bridge, Spanning Mississippi River between IL & MO, Alton, Madison County, IL

  7. High reduction transaxle for electric vehicle

    SciTech Connect

    Kalns, I.

    1987-10-27

    In a drivetrain assembly including a prime mover having an output shaft and a transmission operative to provide at least first and second speed ratios between input and output drives via first and second planetary gear sets respectively including first and second sun gears, first and second ring gears, and first and second sets of planet gears in continuous mesh with their associated sun and ring gears and respectively carried by first and second planet carriers; the improvement is described comprising: drive means including the input drive continuously interconnecting the prime mover output shaft with the first and second sun gears and driving the first and second sun gears at the same speed, a first drive continuously interconnecting the second carrier with the first ring gear, and a second drive continuously interconnecting the first carrier with the output drive; and first and second brake means operative when engaged to prevent rotation of the first and second ring gears, the transmission operative to provide the first speed ratio when the first brake is engaged and the second brake is disengaged, and the transmission operative to provide the second speed ratio when the first brake is disengaged and the second brake is engaged; a gear differential driving first and second driveshafts; and a fixed speed reduction gear set interposed between the first planetary carrier and the differential and including a three element planetary gear set having sun, ring and planet gear elements. One of the elements is fixed directly to the first planet carrier by an intermediate drive, a second elements is fixed to ground, and the third element is connected directly to the gear differential.

  8. Planetary gear train of automatic transmission

    SciTech Connect

    Hiraiwa, K.

    1987-03-31

    A planetary gear train is described for an automatic transmission having input and output shafts, comprising: a first planetary gear unit including a first sun gear, a first internal gear and a first pinion carrier; a second planetary gear unit including a second sun gear, a second internal gear and a second pinion carrier, the first internal gear and the second pinion carrier being constantly connected to the output shaft; a first brake unit capable of braking the first and second sun gears which are connected to each other to rotate together; a clutch through which the first pinion carrier is connectable to the input shaft; a second brake unit capable of braking the first pinion carrier; a third brake unit capable of braking the second internal gear; and first and second groups of one-way means which are parallelly interposed between the input shaft and the first sun gear and arranged in a mutually reversed relationship so that the power transmission from the input shaft to the first sun gear and that from the first sun gear to the input shaft are respectively carried out by the first and second groups of one-way means.

  9. Investigation into nitrided spur gears

    SciTech Connect

    Yilbas, B.S.; Coban, A.; Nickel, J.; Sunar, M.; Sami, M.; Abdul Aleem, B.J.

    1996-12-01

    The cold forging method has been widely used in industry to produce machine parts. In general, gears are produced by shaping or hobbing. One of the shaping techniques is precision forging, which has several advantages over hobbing. In the present study, cold forging of spur gears from Ti-6Al-4V material is introduced. To improve the surface properties of the resulting gears, plasma nitriding was carried out. Nuclear reaction analysis was carried out to obtain the nitrogen concentration, while the micro-PIXE technique was used to determine the elemental distribution in the matrix after forging and nitriding processes. Scanning electron microscopy and x-ray powder diffraction were used to investigate the metallurgical changes and formation of nitride components in the surface region. Microhardness and friction tests were carried out to measure the hardness depth profile and friction coefficient at the surface. Finally, scoring failure tests were conducted to determine the rotational speed at which the gears failed. Three distinct regions were obtained in the nitride region, and at the initial stages of the scoring tests, failure in surface roughness was observed in the vicinity of the tip of the gear tooth. This occurred at a particular rotational speed and work input.

  10. Automobile transmission with output shaft parallel to crank shaft and parking gear fixed to the output shaft

    SciTech Connect

    Kubo, S.; Kuramochi, K.; Kyushima, T.

    1987-06-30

    A driving device is described for an automobile having axles, driving wheels supported by the axles and an engine located proximate the driving wheels, having a crankshaft disposed substantially parallel to the axles supporting the driving wheels, the device comprising: a fluid-type torque converter having coaxial input and output members and disposed on one axial side of the engine connected to and coaxial with the crankshaft; an auxiliary speed change gear assembly having coaxial input and output members and disposed on one axial side of the torque converter remote from the engine with the input member connected to and coaxial of the torque converter; the output member of the auxiliary speed change gear assembly is provided in the shape of a gear; a transmission shaft disposed substantially parallel to the auxiliary speed change gear assembly; a driven gear having a disc portion and toothed peripheral portion; a drive gear drivingly connected to the other end of the transmission shaft closer to the torque converter than the one end of the transmission shaft; a final reduction gear disposed between the driving wheels to be in meshing engagement with the drive gear to transmit power to the axles; a parking gear comprising an annular gear element fixed by bolts proximate the toothed peripheral portion to the axial side surface from which the transmission shaft extends toward the other end. The parking gear is supported by the disc portion for rotation with the driven gear; and means for selectively engaging the parking gear to prevent rotation of shaft when automobile is in parking condition.

  11. Development of a gear vibration indicator and its application in gear wear monitoring

    NASA Astrophysics Data System (ADS)

    Hu, Chongqing; Smith, Wade A.; Randall, Robert B.; Peng, Zhongxiao

    2016-08-01

    Gear tooth wear is an inevitable phenomenon and has a significant influence on gear dynamic features. Although vibration analysis has been widely used to diagnose localised gear tooth faults, its techniques for gear wear monitoring have not been well-established. This paper aims at developing a vibration indicator to evaluate the effects of wear on gear performance. For this purpose, a gear state vector is extracted from time synchronous averaged gear signals to describe the gear state. This gear state vector consists of the sideband ratios obtained from a number of tooth meshing harmonics and their sidebands. Then, two averaged logarithmic ratios, ALR and mALR, are defined with fixed and moving references, respectively, to provide complementary information for gear wear monitoring. Since a fixed reference is utilised in the definition of ALR, it reflects the cumulated wear effects on the gear state. An increase in the ALR value indicates that the gear state deviates further from its reference condition. With the use of a moving reference, the indicator mALR shows changes in the gear state within short time intervals, making it suitable for wear process monitoring. The efficiency of these vibration indicators is demonstrated using experimental results from two sets of tests, in which the gears experienced different wear processes. In addition to gear wear monitoring, the proposed indicators can be used as general parameters to detect the occurrence of other faults, such as a tooth crack or shaft misalignment, because these faults would also change the gear vibrations.

  12. School Counseling Programs: Comparing GEAR UP Schools with Non-GEAR UP Schools

    ERIC Educational Resources Information Center

    Thorngren, Jill M.; Nelson, Mark D.; Baker, Larry J.

    2004-01-01

    A survey was conducted using qualitative means to assess school counseling programs in Montana. Schools that were demonstration schools in a federal initiative, Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP) were compared to non-GEAR UP schools. Several differences between GEAR UP and non-GEAR UP schools are noted and…

  13. Speed reducing or increasing planetary gear apparatus

    SciTech Connect

    Minegishi, K.; Ishida, T.

    1989-07-04

    This patent describes a planetary gear apparatus. It includes: an external gear mounted on an input shaft with an eccentric member and a bearing fitted onto the eccentric member therebetween; an internal gear engaging with the external gear, the internal gear being coaxial with respect to the input shaft; an output shaft for outputting a reduced rotational force; and a drive for coupling the external gear and the output shaft, the planetary gear apparatus being adapted to transmit the rotational force of the input shaft to the output shaft after it has reduced the speed of the rotational force, or to transmit the rotational force of the output shaft to the input shaft after it has increased the speed of the rotational force by fixing the internal gear.

  14. The NASA landing gear test airplane

    NASA Technical Reports Server (NTRS)

    Carter, John F.; Nagy, Christopher J.

    1995-01-01

    A tire and landing gear test facility has been developed and incorporated into a Convair 990 aircraft. The system can simulate tire vertical load profiles to 250,000 lb, sideslip angles to 15 degrees, and wheel braking on actual runways. Onboard computers control the preprogrammed test profiles through a feedback loop and also record three axis loads, tire slip angle, and tire condition. The aircraft to date has provided tire force and wear data for the Shuttle Orbiter tire on three different runways and at east and west coast landing sites. This report discusses the role of this facility in complementing existing ground tire and landing gear test facilities, and how this facility can simultaneously simulate the vertical load, tire slip, velocity, and surface for an entire aircraft landing. A description is given of the aircraft as well as the test system. An example of a typical test sequence is presented. Data collection and reduction from this facility are discussed, as well as accuracies of calculated parameters. Validation of the facility through ground and flight tests is presented. Tests to date have shown that this facility can operate at remote sites and gather complete data sets of load, slip, and velocity on actual runway surfaces. The ground and flight tests have led to a successful validation of this test facility.

  15. Swimming bacteria power microscopic gears.

    SciTech Connect

    Sokolov, A.; Apodaca, M. M.; Grzybowski, B. A.; Aranson, I. S.; Materials Science Division; Princeton Univ.; Northwestern Univ.

    2010-01-19

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be 'rectified' under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms.

  16. Swimming bacteria power microscopic gears.

    PubMed

    Sokolov, Andrey; Apodaca, Mario M; Grzybowski, Bartosz A; Aranson, Igor S

    2010-01-19

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be "rectified" under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears' angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms.

  17. Sequencing device utilizing planetary gear set

    NASA Technical Reports Server (NTRS)

    Appleberry, W. T. (Inventor)

    1979-01-01

    A planetary (epicyclic) gear set is provided with a reversible rotating input shaft and individual outputs shafts actuated, respectively, by the ring gear and planet gear carrier. Latch means is positioned to selectively and automatically stop the ring gear or carrier member while releasing the other to provide the desired sequential output operation. The output shafts are reversed in sequence and direction of rotation by reversing rotational direction of the input shaft.

  18. Avoiding troubles in large gear boxes

    SciTech Connect

    Abou-Haidar, A.N.

    1995-05-08

    This article describes how attention to details such as moisture, contamination, and mechanical loading pays off in troublefree service. Most problems in large gear boxes occur with gears and bearings. Their failure modes and causes should be carefully analyzed to determine the proper corrective action. If gears are selected properly and maintained while in operation, they should last 20 or 30 yr. Gears usually fail because an interruption in operation causes wear and surface fatigue.

  19. Computer simulation of gear tooth manufacturing processes

    NASA Technical Reports Server (NTRS)

    Mavriplis, Dimitri; Huston, Ronald L.

    1990-01-01

    The use of computer graphics to simulate gear tooth manufacturing procedures is discussed. An analytical basis for the simulation is established for spur gears. The simulation itself, however, is developed not only for spur gears, but for straight bevel gears as well. The applications of the developed procedure extend from the development of finite element models of heretofore intractable geometrical forms, to exploring the fabrication of nonstandard tooth forms.

  20. Feed-forward control of gear mesh vibration using piezoelectric actuators

    NASA Technical Reports Server (NTRS)

    Montague, Gerald T.; Kascak, Albert F.; Palazzolo, Alan; Manchala, Daniel; Thomas, Erwin

    1994-01-01

    This paper presents a novel means for suppressing gear mesh-related vibrations. The key components in this approach are piezoelectric actuators and a high-frequency, analog feed-forward controller. Test results are presented and show up to a 70-percent reduction in gear mesh acceleration and vibration control up to 4500 Hz. The principle of the approach is explained by an analysis of a harmonically excited, general linear vibratory system.

  1. Effects of construction changes in the teeth of a gear transmission on acoustic properties.

    PubMed

    Wieczorek, Andrzej

    2012-01-01

    This paper presents results of experimental research on the acoustic properties of gear wheels with high-profile teeth with differentiated tooth height. Those results showed that gear transmissions with high-profile teeth have the best acoustic properties, with the value of the transverse contact ratio εα ≈ 2.0. They also showed that a reduction in tooth height, and thereby in contact ratio, increased the sound pressure level.

  2. 50 CFR 622.272 - Authorized gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Dolphin and Wahoo Fishery Off the Atlantic States § 622.272 Authorized gear. (a) Atlantic dolphin and wahoo—(1) Authorized gear. The following are the only authorized gear types in the fisheries for dolphin and wahoo in...

  3. 50 CFR 622.272 - Authorized gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Dolphin and Wahoo Fishery Off the Atlantic States § 622.272 Authorized gear. (a) Atlantic dolphin and wahoo—(1) Authorized gear. The following are the only authorized gear types in the fisheries for dolphin and wahoo in...

  4. Modification Of Gear Teeth To Reduce Vibrations

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Oswald, Fred B.; Lin, Hsiang Hsi

    1990-01-01

    Computer simulations yield data useful in designing for low noise. Effects of modifications in shape of gear teeth upon static transmission error and dynamic loading of gears now analyzed systematically. Design curves generated by conducting numerical simulations of dynamic effects at successive incremental modifications of gear systems operated at various applied loads. Modifications that result in minimum dynamic effect determined from design curves.

  5. 50 CFR 665.804 - Gear identification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear identification. 665.804 Section 665... Fisheries § 665.804 Gear identification. (a) Identification. The operator of each permitted vessel in the... action. Longline gear not marked in compliance with paragraph (a) of this section and found deployed...

  6. 50 CFR 665.104 - Gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear restrictions. 665.104 Section 665... § 665.104 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for American Samoa bottomfish MUS with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear....

  7. 50 CFR 300.109 - Gear disposal.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 11 2014-10-01 2014-10-01 false Gear disposal. 300.109 Section 300.109... Antarctic Marine Living Resources § 300.109 Gear disposal. (a) The operator of a harvesting vessel may not... fishing vessels or gear, or that may catch fish or cause damage to any marine resource, including...

  8. 50 CFR 665.406 - Gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear restrictions. 665.406 Section 665.406... Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for bottomfish with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear. Possession of a bottom trawl and...

  9. 50 CFR 665.605 - Gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Gear restrictions. 665.605 Section 665... Fisheries § 665.605 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for PRIA bottomfish MUS with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear....

  10. 50 CFR 665.464 - Gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear restrictions. 665.464 Section 665.464 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 665.464 Gear restrictions. Only selective gear may be used to harvest coral from any precious...

  11. 50 CFR 665.664 - Gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear restrictions. 665.664 Section 665.664 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fisheries § 665.664 Gear restrictions. Only selective gear may be used to harvest coral from any...

  12. 50 CFR 665.664 - Gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear restrictions. 665.664 Section 665.664 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fisheries § 665.664 Gear restrictions. Only selective gear may be used to harvest coral from any...

  13. 50 CFR 665.264 - Gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Gear restrictions. 665.264 Section 665.264 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear restrictions. Only selective gear may be used to harvest coral from any precious coral permit area....

  14. 50 CFR 665.264 - Gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Gear restrictions. 665.264 Section 665.264 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear restrictions. Only selective gear may be used to harvest coral from any precious coral permit area....

  15. 50 CFR 665.164 - Gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear restrictions. 665.164 Section 665.164 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 665.164 Gear restrictions. Only selective gear may be used to harvest coral from any precious...

  16. 50 CFR 648.163 - Gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gear restrictions. 648.163 Section 648.163... Bluefish Fishery § 648.163 Gear restrictions. If the Council determines through its annual review or framework adjustment process that gear restrictions are necessary to assure that the fishing mortality...

  17. 50 CFR 665.164 - Gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Gear restrictions. 665.164 Section 665.164 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 665.164 Gear restrictions. Only selective gear may be used to harvest coral from any precious...

  18. 50 CFR 665.104 - Gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Gear restrictions. 665.104 Section 665... § 665.104 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for American Samoa bottomfish MUS with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear....

  19. 50 CFR 665.664 - Gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Gear restrictions. 665.664 Section 665.664 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fisheries § 665.664 Gear restrictions. Only selective gear may be used to harvest coral from any...

  20. 50 CFR 665.605 - Gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear restrictions. 665.605 Section 665... Fisheries § 665.605 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for PRIA bottomfish MUS with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear....

  1. 50 CFR 665.664 - Gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Gear restrictions. 665.664 Section 665.664 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fisheries § 665.664 Gear restrictions. Only selective gear may be used to harvest coral from any...

  2. 50 CFR 665.104 - Gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear restrictions. 665.104 Section 665.104..., DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC American Samoa Fisheries § 665.104 Gear... trawls and bottom set gillnets is prohibited. (b) Possession of gear. The possession of a bottom trawl...

  3. 50 CFR 665.605 - Gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Gear restrictions. 665.605 Section 665... Fisheries § 665.605 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for PRIA bottomfish MUS with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear....

  4. 50 CFR 665.804 - Gear identification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Gear identification. 665.804 Section 665... Fisheries § 665.804 Gear identification. (a) Identification. The operator of each permitted vessel in the... action. Longline gear not marked in compliance with paragraph (a) of this section and found deployed...

  5. 50 CFR 665.406 - Gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear restrictions. 665.406 Section 665... § 665.406 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for bottomfish with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear. Possession of a bottom...

  6. 50 CFR 665.406 - Gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear restrictions. 665.406 Section 665... § 665.406 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for bottomfish with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear. Possession of a bottom...

  7. 50 CFR 665.664 - Gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear restrictions. 665.664 Section 665.664 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION... § 665.664 Gear restrictions. Only selective gear may be used to harvest coral from any precious...

  8. 50 CFR 665.264 - Gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear restrictions. 665.264 Section 665.264 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear restrictions. Only selective gear may be used to harvest coral from any precious coral permit area....

  9. 50 CFR 648.203 - Gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Gear restrictions. 648.203 Section 648... Atlantic Herring Fishery § 648.203 Gear restrictions. (a) Midwater trawl gear may only be used by a vessel... Nantucket Lightship Area as described in § 648.81(c)(1), provided it complies with the midwater trawl...

  10. 50 CFR 665.804 - Gear identification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Gear identification. 665.804 Section 665... Fisheries § 665.804 Gear identification. (a) Identification. The operator of each permitted vessel in the... action. Longline gear not marked in compliance with paragraph (a) of this section and found deployed...

  11. 50 CFR 300.109 - Gear disposal.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Gear disposal. 300.109 Section 300.109... Antarctic Marine Living Resources § 300.109 Gear disposal. (a) The operator of a harvesting vessel may not... fishing vessels or gear, or that may catch fish or cause damage to any marine resource, including...

  12. 50 CFR 665.464 - Gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Gear restrictions. 665.464 Section 665.464 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 665.464 Gear restrictions. Only selective gear may be used to harvest coral from any precious...

  13. 50 CFR 665.164 - Gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Gear restrictions. 665.164 Section 665.164 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 665.164 Gear restrictions. Only selective gear may be used to harvest coral from any precious...

  14. 50 CFR 665.264 - Gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear restrictions. 665.264 Section 665.264..., DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC Hawaii Fisheries § 665.264 Gear restrictions. Only selective gear may be used to harvest coral from any precious coral permit area....

  15. 50 CFR 665.804 - Gear identification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear identification. 665.804 Section 665... Fisheries § 665.804 Gear identification. (a) Identification. The operator of each permitted vessel in the... action. Longline gear not marked in compliance with paragraph (a) of this section and found deployed...

  16. 50 CFR 665.104 - Gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear restrictions. 665.104 Section 665... § 665.104 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for American Samoa bottomfish MUS with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear....

  17. 50 CFR 665.164 - Gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear restrictions. 665.164 Section 665.164 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 665.164 Gear restrictions. Only selective gear may be used to harvest coral from any precious...

  18. 50 CFR 665.104 - Gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Gear restrictions. 665.104 Section 665... § 665.104 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for American Samoa bottomfish MUS with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear....

  19. 50 CFR 665.464 - Gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear restrictions. 665.464 Section 665.464 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION... Gear restrictions. Only selective gear may be used to harvest coral from any precious coral permit area....

  20. 50 CFR 665.605 - Gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear restrictions. 665.605 Section 665... Fisheries § 665.605 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for PRIA bottomfish MUS with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear....

  1. 50 CFR 665.605 - Gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear restrictions. 665.605 Section 665.605... § 665.605 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for PRIA bottomfish MUS with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear. Possession of...

  2. 50 CFR 665.464 - Gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear restrictions. 665.464 Section 665.464 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 665.464 Gear restrictions. Only selective gear may be used to harvest coral from any precious...

  3. 50 CFR 665.406 - Gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Gear restrictions. 665.406 Section 665... § 665.406 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for bottomfish with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear. Possession of a bottom...

  4. 50 CFR 665.164 - Gear restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear restrictions. 665.164 Section 665.164..., DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES IN THE WESTERN PACIFIC American Samoa Fisheries § 665.164 Gear restrictions. Only selective gear may be used to harvest coral from any precious coral permit area....

  5. 50 CFR 300.109 - Gear disposal.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 11 2012-10-01 2012-10-01 false Gear disposal. 300.109 Section 300.109... Antarctic Marine Living Resources § 300.109 Gear disposal. (a) The operator of a harvesting vessel may not... fishing vessels or gear, or that may catch fish or cause damage to any marine resource, including...

  6. 50 CFR 665.264 - Gear restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear restrictions. 665.264 Section 665.264 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear restrictions. Only selective gear may be used to harvest coral from any precious coral permit area....

  7. 50 CFR 648.203 - Gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Gear restrictions. 648.203 Section 648... Atlantic Herring Fishery § 648.203 Gear restrictions. (a) Midwater trawl gear may only be used by a vessel... Nantucket Lightship Area as described in § 648.81(c)(1), provided it complies with the midwater trawl...

  8. 50 CFR 648.203 - Gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Gear restrictions. 648.203 Section 648... Atlantic Herring Fishery § 648.203 Gear restrictions. (a) Midwater trawl gear may only be used by a vessel... Nantucket Lightship Area as described in § 648.81(c)(1), provided it complies with the midwater trawl...

  9. 50 CFR 665.464 - Gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Gear restrictions. 665.464 Section 665.464 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 665.464 Gear restrictions. Only selective gear may be used to harvest coral from any precious...

  10. 50 CFR 300.109 - Gear disposal.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 11 2013-10-01 2013-10-01 false Gear disposal. 300.109 Section 300.109... Antarctic Marine Living Resources § 300.109 Gear disposal. (a) The operator of a harvesting vessel may not... fishing vessels or gear, or that may catch fish or cause damage to any marine resource, including...

  11. 50 CFR 648.203 - Gear restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Gear restrictions. 648.203 Section 648... Atlantic Herring Fishery § 648.203 Gear restrictions. (a) Midwater trawl gear may only be used by a vessel... Nantucket Lightship Area as described in § 648.81(c)(1), provided it complies with the midwater trawl...

  12. 50 CFR 665.406 - Gear restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Gear restrictions. 665.406 Section 665... § 665.406 Gear restrictions. (a) Bottom trawls and bottom set gillnets. Fishing for bottomfish with bottom trawls and bottom set gillnets is prohibited. (b) Possession of gear. Possession of a bottom...

  13. 50 CFR 665.804 - Gear identification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear identification. 665.804 Section 665... Fisheries § 665.804 Gear identification. (a) Identification. The operator of each permitted vessel in the... action. Longline gear not marked in compliance with paragraph (a) of this section and found deployed...

  14. Casimir torque on a cylindrical gear

    NASA Astrophysics Data System (ADS)

    Vaidya, Varun

    2014-08-01

    I utilize effective field theory(EFT) techniques to calculate the Casimir torque on a cylindrical gear in the presence of a polarizable but neutral object and present results for the energy and torque as a function of angle for a gear with multiple cogs, as well as for the case of a concentric cylindrical gear.

  15. Gear teeth impacts in hydrodynamic conjunctions promoting idle gear rattle

    NASA Astrophysics Data System (ADS)

    Theodossiades, S.; Tangasawi, O.; Rahnejat, H.

    2007-06-01

    The rattle phenomenon in vehicular transmissions and its impact on the automotive industry have been widely reported in the literature. A variety of palliative measures have been suggested for attenuation of rattle such as use of backlash eliminators, clutch dampers or dual-mass flywheels. These palliative measures incur further costs and can have untoward implications in powertrain noise and vibration problems. A fundamental investigation of the dynamics of impacting gears is undoubtedly the way forward for a root cause solution. This paper introduces a new approach for understanding the interactions between the transmission gears during engine idle conditions by taking into account the effect of lubrication. Gear impacting surfaces are treated as lubricated conjunctions rather than the usually reported dry impacting solids. Depending on load and speed of entraining motion of the lubricant into the contact domains, the regime of lubrication alters. In this paper, the influence of lubricant in torsional vibration of lightly loaded idling gears is examined which promotes iso-viscous hydrodynamic conditions. It is shown that the lubricant film under these conditions behaves as a time-varying nonlinear spring-damper element. Spectral analysis of the system response is compared to the findings of the linearised system.

  16. Redundant Gear Train

    NASA Technical Reports Server (NTRS)

    Packard, D. T.

    1983-01-01

    Tandem harmonic drives are immune to single-point failure. One mechanism continues transmitting power regardless of how other fails. Harmonic drive mechanism, combination of elliptical wave generator and tooth differential between flexible spline and circular spline produces rotational speed reduction in compact volume.

  17. Recent manufacturing advances for spiral bevel gears

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Bill, Robert C.

    1991-01-01

    The U.S. Army Aviation Systems Command (AVSCOM), through the Propulsion Directorate at NASA Lewis Research Center, has recently sponsored projects to advance the manufacturing process for spiral bevel gears. This type of gear is a critical component in rotary-wing propulsion systems. Two successfully completed contracted projects are described. The first project addresses the automated inspection of spiral bevel gears through the use of coordinate measuring machines. The second project entails the computer-numerical-control (CNC) conversion of a spiral bevel gear grinding machine that is used for all aerospace spiral bevel gears. The results of these projects are described with regard to the savings effected in manufacturing time.

  18. Asymmetric gear rectifies random robot motion

    NASA Astrophysics Data System (ADS)

    Li, He; Zhang, H. P.

    2013-06-01

    We experimentally study the dynamics of centimetric robots and their interactions with rotary gears through inelastic collisions. Under the impacts of self-propelled robots, a gear with symmetric teeth diffuses with no preferred direction of motion. An asymmetric gear, however, rectifies random motion of nearby robots which, in return, exert a torque on the gear and drive it into unidirectional motion. Rectification efficiency increases with the degree of gear asymmetry. Our work demonstrates that asymmetric environments can be used to rectify and extract energy from random motion of macroscopic self-propelled particles.

  19. Recent manufacturing advances for spiral bevel gears

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Bill, Robert C.

    1991-01-01

    The U.S. Army Aviation Systems Command (AVSCOM), through the Propulsion Directorate at NASA LRC, has recently sponsored projects to advance the manufacturing process for spiral bevel gears. This type of gear is a critical component in rotary-wing propulsion systems. Two successfully completed contracted projects are described. The first project addresses the automated inspection of spiral bevel gears through the use of coordinate measuring machines. The second project entails the computer-numerical-control (CNC) conversion of a spiral bevel gear grinding machine that is used for all aerospace spiral bevel gears. The results of these projects are described with regard to the savings effected in manufacturing time.

  20. Space lubrication and performance of harmonic drive gears

    NASA Astrophysics Data System (ADS)

    Schafer, I.; Bourlier, P.; Hantschack, F.; Roberts, E. W.; Lewis, S. D.; Forster, D. J.; John, C.

    2005-07-01

    Harmonic Drive gears are commonly used in space mechanisms. However, lubrication is a critical aspect for proper, effective performance. This paper describes the principle of operation, explains the key parameters that define gear performance and discusses the nature of the various tribological interfaces to be found within HD gears and which call for effective lubrication. Test data are presented on a compact type of harmonic Drive, type CSD 20, that has a reduction ratio of 160:1. Two such HD gears have been lubricated with two space greases namely Maplub SH050a (a grease containing Nye 2001 oil and PTFE) and Maplub PF100a (a grease containing Z25 oil and PTFE). These units have been subjected to thermal-vacuum testing during which measurements were made of input torque, efficiency, break-out torque and no-load backdriving torque. The dependency of these parameters on output load, rotational speed and temperature have been quantified. The work identifies the interface between the wave generator's outer race and the inside surface of the flexspline as the most tribologically demanding and highlights the importance of achieving effective lubrication in this area.

  1. GEAR UP Aspirations Project Evaluation

    ERIC Educational Resources Information Center

    Trimble, Brad A.

    2013-01-01

    The purpose of this study was to conduct a formative evaluation of the first two years of the Gaining Early Awareness and Readiness for Undergraduate Programs (GEAR UP) Aspirations Project (Aspirations) using a Context, Input, Process, and Product (CIPP) model so as to gain an in-depth understanding of the project during the middle school…

  2. Illinois Shifting Gears Policy Evaluation

    ERIC Educational Resources Information Center

    Weitzel, Peter C.

    2009-01-01

    Illinois Shifting Gears is a multilevel initiative that has simultaneously created bridge programs in the field and altered state policy to facilitate the creation of more programs in the future. These efforts have informed each other, giving policymakers the opportunity to interact with practitioners, troubleshoot bridge programs, and make…

  3. Statistical modification analysis of helical planetary gears based on response surface method and Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Guo, Fan

    2015-11-01

    Tooth modification technique is widely used in gear industry to improve the meshing performance of gearings. However, few of the present studies on tooth modification considers the influence of inevitable random errors on gear modification effects. In order to investigate the uncertainties of tooth modification amount variations on system's dynamic behaviors of a helical planetary gears, an analytical dynamic model including tooth modification parameters is proposed to carry out a deterministic analysis on the dynamics of a helical planetary gear. The dynamic meshing forces as well as the dynamic transmission errors of the sun-planet 1 gear pair with and without tooth modifications are computed and compared to show the effectiveness of tooth modifications on gear dynamics enhancement. By using response surface method, a fitted regression model for the dynamic transmission error(DTE) fluctuations is established to quantify the relationship between modification amounts and DTE fluctuations. By shifting the inevitable random errors arousing from manufacturing and installing process to tooth modification amount variations, a statistical tooth modification model is developed and a methodology combining Monte Carlo simulation and response surface method is presented for uncertainty analysis of tooth modifications. The uncertainly analysis reveals that the system's dynamic behaviors do not obey the normal distribution rule even though the design variables are normally distributed. In addition, a deterministic modification amount will not definitely achieve an optimal result for both static and dynamic transmission error fluctuation reduction simultaneously.

  4. Dynamic and Flight Tests on Rubber-Cord and Oleo-Rubber-Disk Landing Gears for an F6C-4 Airplane

    NASA Technical Reports Server (NTRS)

    Peck, William C

    1932-01-01

    The investigation described in this report was conducted for the purpose of comparing an oleo-rubber-disk and a rubber-cord landing gear, built for use on an F6C-4 airplane. The investigation consisted of drop tests under various loading conditions and flight tests on an F6C-4 airplane. In the drop tests the total work done on each gear and the work done on each of the shock-absorbing units were determined. For both drop tests and flight tests the maximum loads and accelerations were determined. The comparative results showed that the oleo gear was slightly superior in reducing the ordinary landing shocks, that it had a greater capacity for work, and that it was very superior in the reduction of the rebound. The results further showed that for drops comparable to very severe landings, the rubber-cord gear was potentially more effective as a shock-reducing mechanism. However, due to the construction of this chassis, which limited the maximum elongation of the cords, this gear was incapable of withstanding as severe tests as the oleo gear. The action of the oleo gear was greatly inferior to the action of an ideal gear. The maximum accelerations encountered during the flight tests for severe landings were 3.64g for the rubber-cord gear and 2.27g for the oleo gear. These were less than those experienced in free drops of 7 inches on either gear.

  5. 75 FR 44924 - Fisheries of the Northeastern United States; Northeast Multispecies Fishery; Trip Limit Reduction...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-30

    ... States; Northeast Multispecies Fishery; Trip Limit Reduction and Trawl Gear Restriction AGENCY: National...: Temporary rule; inseason adjustment of landing limits and gear requirements. SUMMARY: This action decreases... of trawl gear in parts of the U.S./Canada Management Area to reduce the harvest of Georges Bank...

  6. Three dimensional finite element stress predictions of spur gears compared to gear fatigue rig measurements

    SciTech Connect

    Ozkul, M.

    1989-01-01

    A three dimensional finite element analysis technique has been developed for evaluating the gear tooth contact and fillet bending stresses. The method is based on an isoparametric formulation using 20-noded solid elements and the sub-structure approach to minimize computer core usage. The analysis has been applied to a test case of LCR spur gears specifically designed for pitting endurance testing on a gear fatigue rig. The analysis results are compared with strain gauge results obtained from gear fatigue rig to determine allowables for gear tooth stressing. They are finally compared to the tooth stresses obtained using a gear teeth dynamic model for further substantiation.

  7. Face Gear Drive with Spur Involute Pinion: Geometry, Generation by a Worm, Stress Analysis

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Fuentes, Alfonso; Zanzi, Claudio; Pontiggia, Matteo; Handschuh, Robert F. (Technical Monitor)

    2002-01-01

    A face gear drive with a spur involute pinion is considered. The generation of the face gear is based on application of a grinding or cutting worm whereas the conventional method of generation is based on application of an involute shaper. An analytical approach is proposed for the determination of: (1) the worm thread surface; (2) avoidance of singularities of the worm thread surface, (air) dressing of the worm; and (3) determination of stresses of the face-gear drive. A computer program for simulation of meshing and contact of the pinion and face-gear has been developed. Correction of machine-tool settings is proposed for reduction of the shift of the bearing contact caused by misalignment. An automatic development of the model of five contacting teeth has been proposed for stress analysis. Numerical examples for illustration of the developed theory are provided.

  8. Geared rotor dynamic methodologies for advancing prognostic modeling capabilities in rotary-wing transmission systems

    NASA Astrophysics Data System (ADS)

    Stringer, David Blake

    The overarching objective in this research is the development of a robust, rotor dynamic, physics based model of a helicopter drive train as a foundation for the prognostic modeling for rotary-wing transmissions. Rotorcrafts rely on the integrity of their drive trains for their airworthiness. Drive trains rely on gear technology for their integrity and function. Gears alter the vibration characteristics of a mechanical system and significantly contribute to noise, component fatigue, and personal discomfort prevalent in rotorcraft. This research effort develops methodologies for generating a rotor dynamic model of a rotary-wing transmission based on first principles, through (i) development of a three-dimensional gear-mesh stiffness model for helical and spur gears and integration of this model in a finite element rotor dynamic model, (ii) linear and nonlinear analyses of a geared system for comparison and validation of the gear-mesh model, (iii) development of a modal synthesis technique for potentially providing model reduction and faster analysis capabilities for geared systems, and (iv) extension of the gear-mesh model to bevel and epicyclic configurations. In addition to model construction and validation, faults indigenous to geared systems are presented and discussed. Two faults are selected for analysis and seeded into the transmission model. Diagnostic vibration parameters are presented and used as damage indicators in the analysis. The fault models produce results consistent with damage experienced during experimental testing. The results of this research demonstrate the robustness of the physics-based approach in simulating multiple normal and abnormal conditions. The advantages of this physics-based approach, when combined with contemporary probabilistic and time-series techniques, provide a useful method for improving health monitoring technologies in mechanical systems.

  9. Expansion of epicyclic gear dynamic analysis program

    NASA Technical Reports Server (NTRS)

    Boyd, Linda Smith; Pike, James A.

    1987-01-01

    The multiple mesh/single stage dynamics program is a gear tooth analysis program which determines detailed geometry, dynamic loads, stresses, and surface damage factors. The program can analyze a variety of both epicyclic and single mesh systems with spur or helical gear teeth including internal, external, and buttress tooth forms. The modifications refine the options for the flexible carrier and flexible ring gear rim and adds three options: a floating Sun gear option; a natural frequency option; and a finite element compliance formulation for helical gear teeth. The option for a floating Sun incorporates two additional degrees of freedom at the Sun center. The natural frequency option evaluates the frequencies of planetary, star, or differential systems as well as the effect of additional springs at the Sun center and those due to a flexible carrier and/or ring gear rim. The helical tooth pair finite element calculated compliance is obtained from an automated element breakup of the helical teeth and then is used with the basic gear dynamic solution and stress postprocessing routines. The flexible carrier or ring gear rim option for planetary and star spur gear systems allows the output torque per carrier and ring gear rim segment to vary based on the dynamic response of the entire system, while the total output torque remains constant.

  10. Geared-neutral continuously variable transmission

    SciTech Connect

    Macey, J.P.; Vahabzadeh, H.

    1987-02-24

    A continuously variable transmission is described comprising: input drive means; output drive means, a variable ratio friction belt drive means drivingly connected to the input drive means and including a driven shaft; fixed ratio drive means having an input shaft and an output shaft; selectively engageable first clutch means for connecting the input drive means to the input shaft; planetary gear means having a sun gear connected to the driven shaft, a ring gear drivingly connected with the output drive means and carrier and pinion gear means drivingly connected between the sun gear and the ring gear; second clutch means being selectively engageable for connecting the sun gear to the output drive means; third clutch means being selectively engageable for connecting the output shaft to the carrier and pinion gear means; and oneway clutch means disposed in parallel drive relation with the third clutch means for transmitting torque to the carrier and pinion gear means when the third clutch means is disengaged and the output shaft is attempting to rotate faster than the carrier and pinion gear means.

  11. Precision of spiral-bevel gears

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1983-01-01

    The kinematic errors in spiral bevel gear trains caused by the generation of nonconjugate surfaces, by axial displacements of the gears during assembly, and by eccentricity of the assembled gears were determined. One mathematical model corresponds to the motion of the contact ellipse across the tooth surface, (geometry I) and the other along the tooth surface (geometry II). The following results were obtained: (1) kinematic errors induced by errors of manufacture may be minimized by applying special machine settings, the original error may be reduced by order of magnitude, the procedure is most effective for geometry 2 gears, (2) when trying to adjust the bearing contact pattern between the gear teeth for geometry I gears, it is more desirable to shim the gear axially; for geometry II gears, shim the pinion axially; (3) the kinematic accuracy of spiral bevel drives are most sensitive to eccentricities of the gear and less sensitive to eccentricities of the pinion. The precision of mounting accuracy and manufacture are most crucial for the gear, and less so for the pinion. Previously announced in STAR as N82-30552

  12. Precision of spiral-bevel gears

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.

    1982-01-01

    The kinematic errors in spiral bevel gear trains caused by the generation of nonconjugate surfaces, by axial displacements of the gears during assembly, and by eccentricity of the assembled gears were determined. One mathematical model corresponds to the motion of the contact ellipse across the tooth surface, (geometry I) and the other along the tooth surface (geometry II). The following results were obtained: (1) kinematic errors induced by errors of manufacture may be minimized by applying special machine settings, the original error may be reduced by order of magnitude, the procedure is most effective for geometry 2 gears, (2) when trying to adjust the bearing contact pattern between the gear teeth for geometry 1 gears, it is more desirable to shim the gear axially; for geometry II gears, shim the pinion axially; (3) the kinematic accuracy of spiral bevel drives are most sensitive to eccentricities of the gear and less sensitive to eccentricities of the pinion. The precision of mounting accuracy and manufacture are most crucial for the gear, and less so for the pinion.

  13. 50 CFR 648.51 - Gear and crew restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Gear and crew restrictions. 648.51... Measures for the Atlantic Sea Scallop Fishery § 648.51 Gear and crew restrictions. (a) Trawl vessel gear... long axis of the net. (3) Chafing gear and other gear obstructions—(i) Net obstruction or...

  14. 50 CFR 648.51 - Gear and crew restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Gear and crew restrictions. 648.51... Measures for the Atlantic Sea Scallop Fishery § 648.51 Gear and crew restrictions. (a) Trawl vessel gear... long axis of the net. (3) Chafing gear and other gear obstructions—(i) Net obstruction or...

  15. 50 CFR 697.23 - Restricted gear areas.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Measures § 697.23 Restricted gear areas. (a) Resolution of lobster gear conflicts with fisheries managed... all mobile gear is on board the vessel while inside the area. (ii) Lobster trap gear. From June 16 through September 30 of each fishing year, no fishing vessel with lobster trap gear or person on a...

  16. 50 CFR 697.23 - Restricted gear areas.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Measures § 697.23 Restricted gear areas. (a) Resolution of lobster gear conflicts with fisheries managed... all mobile gear is on board the vessel while inside the area. (ii) Lobster trap gear. From June 16 through September 30 of each fishing year, no fishing vessel with lobster trap gear or person on a...

  17. 50 CFR 697.23 - Restricted gear areas.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Measures § 697.23 Restricted gear areas. (a) Resolution of lobster gear conflicts with fisheries managed... all mobile gear is on board the vessel while inside the area. (ii) Lobster trap gear. From June 16 through September 30 of each fishing year, no fishing vessel with lobster trap gear or person on a...

  18. 50 CFR 697.23 - Restricted gear areas.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Measures § 697.23 Restricted gear areas. (a) Resolution of lobster gear conflicts with fisheries managed... all mobile gear is on board the vessel while inside the area. (ii) Lobster trap gear. From June 16 through September 30 of each fishing year, no fishing vessel with lobster trap gear or person on a...

  19. 50 CFR 697.23 - Restricted gear areas.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Measures § 697.23 Restricted gear areas. (a) Resolution of lobster gear conflicts with fisheries managed... all mobile gear is on board the vessel while inside the area. (ii) Lobster trap gear. From June 16 through September 30 of each fishing year, no fishing vessel with lobster trap gear or person on a...

  20. 29 CFR 1919.19 - Gear requiring welding.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Gear requiring welding. 1919.19 Section 1919.19 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels' Cargo Gear § 1919.19 Gear requiring welding. Chains or other gear which have been lengthened, altered or repaired by welding shall be properly...

  1. 49 CFR 230.92 - Draw gear and draft systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Draw gear and draft systems. 230.92 Section 230.92... Tenders Draw Gear and Draft Systems § 230.92 Draw gear and draft systems. Couplers, draft gear and... condition for service. Driving Gear...

  2. 29 CFR 1919.19 - Gear requiring welding.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Gear requiring welding. 1919.19 Section 1919.19 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels' Cargo Gear § 1919.19 Gear requiring welding. Chains or other gear which have been lengthened, altered or repaired by welding shall be properly...

  3. 29 CFR 1919.19 - Gear requiring welding.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Gear requiring welding. 1919.19 Section 1919.19 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels' Cargo Gear § 1919.19 Gear requiring welding. Chains or other gear which have been lengthened, altered or repaired by welding shall be properly...

  4. 50 CFR 660.219 - Fixed gear identification and marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Fixed gear identification and marking... West Coast Groundfish-Limited Entry Fixed Gear Fisheries § 660.219 Fixed gear identification and marking. (a) Gear identification. (1) Limited entry fixed gear (longline, trap or pot) must be marked...

  5. 50 CFR 660.219 - Fixed gear identification and marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Fixed gear identification and marking... West Coast Groundfish-Limited Entry Fixed Gear Fisheries § 660.219 Fixed gear identification and marking. (a) Gear identification. (1) Limited entry fixed gear (longline, trap or pot) must be marked...

  6. 50 CFR 660.219 - Fixed gear identification and marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Fixed gear identification and marking. 660... Groundfish-Limited Entry Fixed Gear Fisheries § 660.219 Fixed gear identification and marking. (a) Gear identification. (1) Limited entry fixed gear (longline, trap or pot) must be marked at the surface and at...

  7. 50 CFR 622.375 - Authorized and unauthorized gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Authorized and unauthorized gear. 622.375... unauthorized gear. (a) Authorized gear. Subject to the prohibitions on gear/methods specified in § 622.9, the following are the only fishing gears that may be used in the Gulf, Mid-Atlantic, and South Atlantic EEZ...

  8. 49 CFR 230.92 - Draw gear and draft systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Draw gear and draft systems. 230.92 Section 230.92... Tenders Draw Gear and Draft Systems § 230.92 Draw gear and draft systems. Couplers, draft gear and... condition for service. Driving Gear...

  9. 49 CFR 230.92 - Draw gear and draft systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Draw gear and draft systems. 230.92 Section 230.92... Tenders Draw Gear and Draft Systems § 230.92 Draw gear and draft systems. Couplers, draft gear and... condition for service. Driving Gear...

  10. 50 CFR 622.375 - Authorized and unauthorized gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Authorized and unauthorized gear. 622.375... unauthorized gear. (a) Authorized gear. Subject to the prohibitions on gear/methods specified in § 622.9, the following are the only fishing gears that may be used in the Gulf, Mid-Atlantic, and South Atlantic EEZ...

  11. 49 CFR 230.92 - Draw gear and draft systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Draw gear and draft systems. 230.92 Section 230.92... Tenders Draw Gear and Draft Systems § 230.92 Draw gear and draft systems. Couplers, draft gear and... condition for service. Driving Gear...

  12. 29 CFR 1919.19 - Gear requiring welding.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Gear requiring welding. 1919.19 Section 1919.19 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels' Cargo Gear § 1919.19 Gear requiring welding. Chains or other gear which have been lengthened, altered or repaired by welding shall be properly...

  13. 49 CFR 230.92 - Draw gear and draft systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Draw gear and draft systems. 230.92 Section 230.92... Tenders Draw Gear and Draft Systems § 230.92 Draw gear and draft systems. Couplers, draft gear and... condition for service. Driving Gear...

  14. 29 CFR 1919.19 - Gear requiring welding.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Gear requiring welding. 1919.19 Section 1919.19 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels' Cargo Gear § 1919.19 Gear requiring welding. Chains or other gear which have been lengthened, altered or repaired by welding shall be properly...

  15. Swimming bacteria power microscopic gears

    SciTech Connect

    Sokolov, Andrey; Apodaca, Mario M.; Grzybowski, Bartosz A.; Aranson, Igor S.

    2010-01-19

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be “rectified” under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears’ angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms.

  16. Swimming bacteria power microscopic gears

    PubMed Central

    Sokolov, Andrey; Apodaca, Mario M.; Grzybowski, Bartosz A.; Aranson, Igor S.

    2010-01-01

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be “rectified” under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears’ angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms. PMID:20080560

  17. Zero torque gear head wrench

    NASA Technical Reports Server (NTRS)

    Mcdougal, A. R.; Norman, R. M. (Inventor)

    1976-01-01

    A gear head wrench particularly suited for use in applying torque to bolts without transferring torsional stress to bolt-receiving structures is introduced. The wrench is characterized by a coupling including a socket, for connecting a bolt head with a torque multiplying gear train, provided within a housing having an annulus concentrically related to the socket and adapted to be coupled with a spacer interposed between the bolt head and the juxtaposed surface of the bolt-receiving structure for applying a balancing counter-torque to the spacer as torque is applied to the bolt head whereby the bolt-receiving structure is substantially isolated from torsional stress. As a result of the foregoing, the operator of the wrench is substantially isolated from any forces which may be imposed.

  18. Bacteria turn a tiny gear

    SciTech Connect

    2009-01-01

    Thousands of tiny Bacillus subtillis bacteria turn a single gear, just 380 microns across. (A human hair is about 100 microns across.) The method could be used to create micro-machines. Argonne National Laboratory scientist Igor Aronson pioneered this technique. Read more at the New York Times: http://ow.ly/ODfI or at Argonne: http://ow.ly/ODfa Video courtesy Igor Aronson.

  19. High-torque quiet gear

    NASA Astrophysics Data System (ADS)

    Moody, Paul E.

    1995-07-01

    A high-torque quiet gear construction consists of an inner hub having a plurality of circumferentially spaced arms extending radially outwardly therefrom, and an outer ring member having a plurality of circumferentially spaced-teeth extending radially inwardly therefrom. The ring member further includes a plurality of gear formations on an outer surface thereof for intermeshing with other gears. The teeth of the ring member are received in spaced relation in corresponding spaces formed between adjacent arms of the hub. An elastomeric member is received in the space formed between the hub and the ring member to form a resilient correction between the arms of the hub and the teeth of the ring member. The side surfaces of the arms and the teeth extend generally parallel to each other and at least partially overlap in a longitudinal direction. The purpose of this configuration is to place the elastomeric member in compression when torque is applied to the hub. Since elastomeric material is relatively incompressible, the result is low shear loads on the adhesive bonds which hold the elastomeric member to both the hub and outer ring member.

  20. Automatic transmission's Ravigneaux type planetary gear train having two ring gears

    SciTech Connect

    Hiraiwa, K.

    1989-02-07

    A planetary gear system is described comprising: a stationary member; input means for receiving a driving torque; an output shaft; a compound planetary gear train; a clutch group including a first clutch disposed between the input means and the first sun gear for connection and disconnection therebetween, a second clutch disposed between the input means and the second sun gear for connection and disconnection therebetween, and a third clutch disposed between the input means and the pinion carrier for connection and disconnection therebetween; and a holding device group including a first holding device disposed between the first sun gear and the stationary member for holding the first sun gear, a second holding device disposed between the pinion carrier and the stationary member for holding the pinion carrier, and a third holding device disposed between the second ring gear and the stationary member for holding the second ring gear.

  1. Effects of gear box vibration and mass imbalance on the dynamics of multistage gear transmission

    NASA Technical Reports Server (NTRS)

    Choy, F. K.; Tu, Y. K.; Zakrajsek, J. J.; Townsend, D. P.

    1991-01-01

    The dynamic behavior of multistage gear transmission system, with the effects of gear-box-induced vibrations and rotor mass-imbalances is analyzed. The model method, using undamped frequencies and planar mode shapes, is used to reduce the degree-of-freedom of the system. The various rotor-bearing stages as well as lateral and torsional vibrations of each individual stage are coupled through localized gear-mesh-tooth interactions. Gear-box vibrations are coupled to the gear stage dynamics through bearing support forces. Transient and steady state dynamics of lateral and torsional vibrations of the geared system are examined in both time and frequency domain. A typical three-staged geared system is used as an example. Effects of mass-imbalance and gear box vibrations on the system dynamic behavior are presented in terms of modal excitation functions for both lateral and torsional vibrations. Operational characteristics and conclusions are drawn from the results presented.

  2. Lubrication and cooling for high speed gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.

    1985-01-01

    The problems and failures occurring with the operation of high speed gears are discussed. The gearing losses associated with high speed gearing such as tooth mesh friction, bearing friction, churning, and windage are discussed with various ways shown to help reduce these losses and thereby improve efficiency. Several different methods of oil jet lubrication for high speed gearing are given such as into mesh, out of mesh, and radial jet lubrication. The experiments and analytical results for the various methods of oil jet lubrication are shown with the strengths and weaknesses of each method discussed. The analytical and experimental results of gear lubrication and cooling at various test conditions are presented. These results show the very definite need of improved methods of gear cooling at high speed and high load conditions.

  3. Topological and parametric optimization of gear trains

    NASA Astrophysics Data System (ADS)

    Swantner, Albert; Campbell, Matthew I.

    2012-11-01

    A method for automating the design of gear trains comprised of simple, compound, bevel and worm is described. The search process combines topological changes, discrete variable choices and continuous variable optimization. By combing best-first search, implicit enumeration, automated optimization invocation and gradient-based optimization, a near guarantee of the optimal solution can be made. While the combination of methods is specific to gear trains, there are aspects of the work that make it amenable to other engineering design problems. In addition, the topological and discrete modifications to the candidate solutions are specific to gear trains, but the graph grammar methodology that is adopted has been tailored to other problems. This article presents details on the rules that generate feasible gear trains, the evaluation routines used in determining the objective functions and constraints, and the interaction among the three search methods. Resulting gear trains are presented for a variety of gear problems.

  4. Noncircular Gears: Geometry and Visualization MODEL Development

    DTIC Science & Technology

    2012-01-01

    13. SUPPLEMENTARY NOTES david.stringer@us.army.mil 14. ABSTRACT Circular gears are optimized to provide constant torque and speed ratio with low...noise. In conventional automotive applications, a transmission provides the required power, torque , and speed settings using a finite arrangement of...a noncircular gear pair of desired velocity and torque ratio distribution. Finally, to graphically depict the noncircular effects on gear motion

  5. 50 CFR 679.24 - Gear limitations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Gear limitations. 679.24 Section 679.24... § 679.24 Gear limitations. Regulations pertaining to vessel and gear markings are set forth in this... § 300.62 of chapter III of this title. (a) Marking of hook-and-line, longline pot, and pot-and-line...

  6. 50 CFR 679.24 - Gear limitations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear limitations. 679.24 Section 679.24... § 679.24 Gear limitations. Regulations pertaining to vessel and gear markings are set forth in this... § 300.62 of chapter III of this title. (a) Marking of hook-and-line, longline pot, and pot-and-line...

  7. Tool Gear: Infrastructure for Parallel Tools

    SciTech Connect

    May, J; Gyllenhaal, J

    2003-04-17

    Tool Gear is a software infrastructure for developing performance analysis and other tools. Unlike existing integrated toolkits, which focus on providing a suite of capabilities, Tool Gear is designed to help tool developers create new tools quickly. It combines dynamic instrumentation capabilities with an efficient database and a sophisticated and extensible graphical user interface. This paper describes the design of Tool Gear and presents examples of tools that have been built with it.

  8. 50 CFR 679.24 - Gear limitations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear limitations. 679.24 Section 679.24... § 679.24 Gear limitations. Regulations pertaining to vessel and gear markings are set forth in this... § 300.62 of chapter III of this title. (a) Marking of hook-and-line, longline pot, and pot-and-line...

  9. 50 CFR 679.24 - Gear limitations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear limitations. 679.24 Section 679.24... § 679.24 Gear limitations. Regulations pertaining to vessel and gear markings are set forth in this... § 300.62 of chapter III of this title. (a) Marking of hook-and-line, longline pot, and pot-and-line...

  10. 50 CFR 679.24 - Gear limitations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Gear limitations. 679.24 Section 679.24... § 679.24 Gear limitations. Regulations pertaining to vessel and gear markings are set forth in this... § 300.62 of chapter III of this title. (a) Marking of hook-and-line, longline pot, and pot-and-line...

  11. Dynamic loading on parallel shaft gears

    NASA Technical Reports Server (NTRS)

    Lin, H. H. (edward); Huston, R. L.

    1986-01-01

    A computer-based analysis of the dynamic effects of spur gear systems is presented. The method of analysis with its associated computer code is capable of determining the dynamic response of spur gear systems having involute tooth profiles and standard contact ratios. Various parameters affecting the system dynamic behavior are examined. Numerical results of the analysis are compared with semi-empirical formulae, AGMA (American Gear Manufacturers Association) formulae, and experimental data. A close correlation with the experimental data is obtained.

  12. Optimum weight design of functionally graded material gears

    NASA Astrophysics Data System (ADS)

    Jing, Shikai; Zhang, He; Zhou, Jingtao; Song, Guohua

    2015-11-01

    Traditional gear weight optimization methods consider gear tooth number, module, face width or other dimension parameters of gear as design variables. However, due to the complicated form and geometric features peculiar to the gear, there will be large amounts of design parameters in gear design, and the influences of gear parameters changing on gear trains, transmission system and the whole equipment have to be taken into account, which increases the complexity of optimization problem. This paper puts forward to apply functionally graded materials (FGMs) to gears and then conduct the optimization. According to the force situation of gears, the material distribution form of FGM gears is determined. Then based on the performance parameters analysis of FGMs and the practical working demands for gears, a multi-objective optimization model is formed. Finally by using the goal driven optimization (GDO) method, the optimal material distribution is achieved, which makes gear weight and the maximum deformation be minimum and the maximum bending stress do not exceed the allowable stress. As an example, the applying of FGM to automotive transmission gear is conducted to illustrate the optimization design process and the result shows that under the condition of keeping the normal working performance of gear, the method achieves in greatly reducing the gear weight. This research proposes a FGM gears design method that is able to largely reduce the weight of gears by optimizing the microscopic material parameters instead of changing the macroscopic dimension parameters of gears, which reduces the complexity of gear weight optimization problem.

  13. Load Sharing Behavior of Star Gearing Reducer for Geared Turbofan Engine

    NASA Astrophysics Data System (ADS)

    Mo, Shuai; Zhang, Yidu; Wu, Qiong; Wang, Feiming; Matsumura, Shigeki; Houjoh, Haruo

    2017-03-01

    Load sharing behavior is very important for power-split gearing system, star gearing reducer as a new type and special transmission system can be used in many industry fields. However, there is few literature regarding the key multiple-split load sharing issue in main gearbox used in new type geared turbofan engine. Further mechanism analysis are made on load sharing behavior among star gears of star gearing reducer for geared turbofan engine. Comprehensive meshing error analysis are conducted on eccentricity error, gear thickness error, base pitch error, assembly error, and bearing error of star gearing reducer respectively. Floating meshing error resulting from meshing clearance variation caused by the simultaneous floating of sun gear and annular gear are taken into account. A refined mathematical model for load sharing coefficient calculation is established in consideration of different meshing stiffness and supporting stiffness for components. The regular curves of load sharing coefficient under the influence of interactions, single action and single variation of various component errors are obtained. The accurate sensitivity of load sharing coefficient toward different errors is mastered. The load sharing coefficient of star gearing reducer is 1.033 and the maximum meshing force in gear tooth is about 3010 N. This paper provides scientific theory evidences for optimal parameter design and proper tolerance distribution in advanced development and manufacturing process, so as to achieve optimal effects in economy and technology.

  14. Design of spur gears for improved efficiency

    NASA Technical Reports Server (NTRS)

    Anderson, N. E.; Loewenthal, S. H.

    1981-01-01

    A method to calculate spur gear system power loss for a wide range of gear geometries and operating conditions is used to determine design requirements for an efficient gearset. The effects of spur gear size, pitch, ratio, pitch-line-velocity and load on efficiency are shown. A design example is given to illustrate how the method is to be applied. In general, peak efficiencies were found to be greater for larger diameter and fine pitched gears and tare (no-load) losses were found to be significant.

  15. Evaluation of Carburized and Ground Face Gears

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Handschuh, Robert F.; Heath, Gregory F.; Sheth, Vijay

    1999-01-01

    Experimental durability tests were performed on carburized and ground AIS19310 steel face gears. The tests were in support of a Defense Advanced Research Projects Agency (DARPA) Technology Reinvestment Program (TRP) to enhance face-gear technology. The tests were conducted in the NASA Glenn spiral-bevel-gear/face-gear test facility. Tests were run at 2300 rpm face gear speed and at loads of 64, 76, 88, 100, and 112-percent of the design torque of 377 N-m (3340 in-lb). The carburized and ground face gears demonstrated the required durability when run for ten-million cycles at each of the applied loads. Proper installation was critical for the successful operation of the spur pinions and face gears. A large amount of backlash produced tooth contact patterns that approached the inner-diameter edge of the face-gear tooth. Low backlash produced tooth contact patterns that approached the outer-diameter edge of the face-gear tooth. Measured backlashes in the range of 0.178 to 0.254 mm (0.007 to 0.010 in) produced acceptable tooth contact patterns.

  16. A mathematical model of an active control landing gear for load control during impact and roll-out

    NASA Technical Reports Server (NTRS)

    Mcgehee, J. R.; Carden, H. D.

    1976-01-01

    A mathematical model of an active control landing gear (ACOLAG) was developed and programmed for operation on a digital computer. The mathematical model includes theoretical subsonic aerodynamics; first-mode wing bending and torsional characteristics; oleo-pneumatic shock strut with fit and binding friction; closed-loop, series-hydraulic control; empirical tire force-deflection characteristics; antiskid braking; and sinusoidal or random runway roughness. The mathematical model was used to compute the loads and motions for a simulated vertical drop test and a simulated landing impact of a conventional (passive) main landing gear designed for a 2268-kg (5000-lbm) class airplane. Computations were also made for a simply modified version of the passive gear including a series-hydraulic active control system. Comparison of computed results for the passive gear with experimental data shows that the active control landing gear analysis is valid for predicting the loads and motions of an airplane during a symmetrical landing. Computed results for the series-hydraulic active control in conjunction with the simply modified passive gear show that 20- to 30-percent reductions in wing force, relative to those occurring with the modified passive gear, can be obtained during the impact phase of the landing. These reductions in wing force could result in substantial increases in fatigue life of the structure.

  17. New Gear Transmission Error Measurement System Designed

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.

    2001-01-01

    The prime source of vibration and noise in a gear system is the transmission error between the meshing gears. Transmission error is caused by manufacturing inaccuracy, mounting errors, and elastic deflections under load. Gear designers often attempt to compensate for transmission error by modifying gear teeth. This is done traditionally by a rough "rule of thumb" or more recently under the guidance of an analytical code. In order for a designer to have confidence in a code, the code must be validated through experiment. NASA Glenn Research Center contracted with the Design Unit of the University of Newcastle in England for a system to measure the transmission error of spur and helical test gears in the NASA Gear Noise Rig. The new system measures transmission error optically by means of light beams directed by lenses and prisms through gratings mounted on the gear shafts. The amount of light that passes through both gratings is directly proportional to the transmission error of the gears. A photodetector circuit converts the light to an analog electrical signal. To increase accuracy and reduce "noise" due to transverse vibration, there are parallel light paths at the top and bottom of the gears. The two signals are subtracted via differential amplifiers in the electronics package. The output of the system is 40 mV/mm, giving a resolution in the time domain of better than 0.1 mm, and discrimination in the frequency domain of better than 0.01 mm. The new system will be used to validate gear analytical codes and to investigate mechanisms that produce vibration and noise in parallel axis gears.

  18. Low-noise, high-strength, spiral-bevel gears for helicopter transmissions

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Handschuh, Robert F.; Henry, Zachary S.; Litvin, Faydor L.

    1993-01-01

    Improvements in spiral-bevel gear design were investigated to support the Army/NASA Advanced Rotorcraft Transmission program. Program objectives were to reduce weight by 25 percent, reduce noise by 10 dB, and increase life to 5000 hr mean-time-between-removal. To help meet these goals, advanced-design spiral-bevel gears were tested in an OH-58D helicopter transmission using the NASA 500-hp Helicopter Transmission Test Stand. Three different gear designs tested included: (1) the current design of the OH-58D transmission except gear material X-53 instead of AISI 9310; (2) a higher-strength design the same as the current but with a full fillet radius to reduce gear tooth bending stress (and thus, weight); and (3) a lower-noise design the same as the high-strength but with modified tooth geometry to reduce transmission error and noise. Noise, vibration, and tooth strain tests were performed and significant gear stress and noise reductions were achieved.

  19. Modeling, Modal Properties, and Mesh Stiffness Variation Instabilities of Planetary Gears

    NASA Technical Reports Server (NTRS)

    Parker, Robert G.; Lin, Jian; Krantz, Timothy L. (Technical Monitor)

    2001-01-01

    Planetary gear noise and vibration are primary concerns in their applications in helicopters, automobiles, aircraft engines, heavy machinery and marine vehicles. Dynamic analysis is essential to the noise and vibration reduction. This work analytically investigates some critical issues and advances the understanding of planetary gear dynamics. A lumped-parameter model is built for the dynamic analysis of general planetary gears. The unique properties of the natural frequency spectra and vibration modes are rigorously characterized. These special structures apply for general planetary gears with cyclic symmetry and, in practically important case, systems with diametrically opposed planets. The special vibration properties are useful for subsequent research. Taking advantage of the derived modal properties, the natural frequency and vibration mode sensitivities to design parameters are investigated. The key parameters include mesh stiffnesses, support/bearing stiffnesses, component masses, moments of inertia, and operating speed. The eigen-sensitivities are expressed in simple, closed-form formulae associated with modal strain and kinetic energies. As disorders (e.g., mesh stiffness variation. manufacturing and assembling errors) disturb the cyclic symmetry of planetary gears, their effects on the free vibration properties are quantitatively examined. Well-defined veering rules are derived to identify dramatic changes of natural frequencies and vibration modes under parameter variations. The knowledge of free vibration properties, eigen-sensitivities, and veering rules provide important information to effectively tune the natural frequencies and optimize structural design to minimize noise and vibration. Parametric instabilities excited by mesh stiffness variations are analytically studied for multi-mesh gear systems. The discrepancies of previous studies on parametric instability of two-stage gear chains are clarified using perturbation and numerical methods. The

  20. An Assessment of Flap and Main Landing Gear Noise Abatement Concepts

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.; Humphreys, William M., Jr.; Lockard, David P.

    2015-01-01

    A detailed assessment of the acoustic performance of several noise reduction concepts for aircraft flaps and landing gear is presented. Consideration is given to the best performing concepts within the suite of technologies that were evaluated in the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel using an 18 percent scale, semi-span, high-fidelity Gulfstream aircraft model as a test bed. Microphone array measurements were obtained with the model in a landing configuration (flap deflected 39 degrees and the main landing gear deployed or retracted). The effectiveness of each concept over the range of pitch angles, speeds, and directivity angles tested is presented. Comparison of the acoustic spectra, obtained from integration of the beamform maps between the untreated baseline and treated configurations, clearly demonstrates that the flap and gear concepts maintain noise reduction benefits over the entire range of the directivity angles tested.

  1. Detecting gear tooth fracture in a high contact ratio face gear mesh

    NASA Technical Reports Server (NTRS)

    Zakrajsek, James J.; Handschuh, Robert F.; Lewicki, David G.; Decker, Harry J.

    1995-01-01

    This paper summarized the results of a study in which three different vibration diagnostic methods were used to detect gear tooth fracture in a high contact ratio face gear mesh. The NASA spiral bevel gear fatigue test rig was used to produce unseeded fault, natural failures of four face gear specimens. During the fatigue tests, which were run to determine load capacity and primary failure mechanisms for face gears, vibration signals were monitored and recorded for gear diagnostic purposes. Gear tooth bending fatigue and surface pitting were the primary failure modes found in the tests. The damage ranged from partial tooth fracture on a single tooth in one test to heavy wear, severe pitting, and complete tooth fracture of several teeth on another test. Three gear fault detection techniques, FM4, NA4*, and NB4, were applied to the experimental data. These methods use the signal average in both the time and frequency domain. Method NA4* was able to conclusively detect the gear tooth fractures in three out of the four fatigue tests, along with gear tooth surface pitting and heavy wear. For multiple tooth fractures, all of the methods gave a clear indication of the damage. It was also found that due to the high contact ratio of the face gear mesh, single tooth fractures did not significantly affect the vibration signal, making this type of failure difficult to detect.

  2. The transfer function method for gear system dynamics applied to conventional and minimum excitation gearing designs

    NASA Technical Reports Server (NTRS)

    Mark, W. D.

    1982-01-01

    A transfer function method for predicting the dynamic responses of gear systems with more than one gear mesh is developed and applied to the NASA Lewis four-square gear fatigue test apparatus. Methods for computing bearing-support force spectra and temporal histories of the total force transmitted by a gear mesh, the force transmitted by a single pair of teeth, and the maximum root stress in a single tooth are developed. Dynamic effects arising from other gear meshes in the system are included. A profile modification design method to minimize the vibration excitation arising from a pair of meshing gears is reviewed and extended. Families of tooth loading functions required for such designs are developed and examined for potential excitation of individual tooth vibrations. The profile modification design method is applied to a pair of test gears.

  3. Optimal sinusoidal modelling of gear mesh vibration signals for gear diagnosis and prognosis

    NASA Astrophysics Data System (ADS)

    Man, Zhihong; Wang, Wenyi; Khoo, Suiyang; Yin, Juliang

    2012-11-01

    In this paper, the synchronous signal average of gear mesh vibration signals is modelled with the multiple modulated sinusoidal representations. The signal model parameters are optimised against the measured signal averages by using the batch learning of the least squares technique. With the optimal signal model, all components of a gear mesh vibration signal, including the amplitude modulations, the phase modulations and the impulse vibration component induced by gear tooth cracking, are identified and analysed with insight of the gear tooth crack development and propagation. In particular, the energy distribution of the impulse vibration signal, extracted from the optimal signal model, provides sufficient information for monitoring and diagnosing the evolution of the tooth cracking process, leading to the prognosis of gear tooth cracking. The new methodologies for gear mesh signal modelling and the diagnosis of the gear tooth fault development and propagation are validated with a set of rig test data, which has shown excellent performance.

  4. Helical Gears Modified To Decrease Transmission Errors

    NASA Technical Reports Server (NTRS)

    Handschuh, R. F.; Coy, J. J.; Litvin, F. L.; Zhang, J.

    1993-01-01

    Tooth surfaces of helical gears modified, according to proposed design concept, to make gears more tolerant of misalignments and to improve distribution of contact stresses. Results in smaller transmission errors, with concomitant decreases in vibrations and noise and, possibly, increases in service lives.

  5. 50 CFR 648.144 - Gear restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... restrictions—(1) General. (i) Otter trawlers whose owners are issued a black sea bass moratorium permit and... Black Sea Bass Fishery § 648.144 Gear restrictions. Link to an amendment published at 76 FR 60637, Sept. 29, 2011. (a) Trawl gear restrictions—(1) General. (i) Otter trawlers whose owners are issued a...

  6. Gear Lubrication and Cooling Experiment and Analysis

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Akin, L. S.

    1983-01-01

    A gear tooth temperature analysis was performed using a finite element method combined with a calculated heat input, a calculated oil jet impingement depth, and estimated heat transfer coefficients for the different parts of the gear tooth that are oil cooled and air cooled. Experimental measurements of gear tooth average surface temperature and gear tooth instantaneous surface temperature were made with a fast response, infrared, radiometric microscope. Increasing oil pressure has a significant effect on both average surface temperature and peak surface temperature at loads above 1895 N/cm(1083 lb/in) and speeds of 10,000 and 7500 rpm. Both increasing speed (from 5000 to 10,000 rpm) at constant speed cause a significant rise in the average surface temperature and in the instantaneous peak surface temperatures on the gear teeth. The oil jet pressure required to provide the best cooling for gears is the pressure required to obtain full gear tooth impingement. Calculated results for gear tooth temperatures were close to experimental results for various oil jet impingement depths for identical operating conditions.

  7. Computer aided design of spur gear teeth

    NASA Technical Reports Server (NTRS)

    Huston, R. L.; Mavriplis, D.; Oswald, F. B.

    1989-01-01

    Procedures for computer-modeling of spur gear tooth fabrication are given. It is shown that the standard involute tooth form results from a cutter with an involute shape rolling onto a gear blank. Specifically, the envelope of an involute is an involute. Examples are given and applications are discussed.

  8. 50 CFR 665.246 - Gear identification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Gear identification. 665.246 Section 665.246 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear identification. In Permit Area 1, the vessel's official number must be marked legibly on all...

  9. 50 CFR 665.246 - Gear identification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Gear identification. 665.246 Section 665.246 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear identification. In Permit Area 1, the vessel's official number must be marked legibly on all...

  10. 50 CFR 622.243 - Gear identification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Gear identification. 622.243 Section 622.243 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fishery of the South Atlantic Region § 622.243 Gear identification. (a) Golden crab traps and...

  11. 50 CFR 665.246 - Gear identification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Gear identification. 665.246 Section 665.246 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear identification. In Permit Area 1, the vessel's official number must be marked legibly on all...

  12. 50 CFR 665.246 - Gear identification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Gear identification. 665.246 Section 665.246 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear identification. In Permit Area 1, the vessel's official number must be marked legibly on all...

  13. 50 CFR 622.376 - Gear identification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Gear identification. 622.376 Section 622.376 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Migratory Pelagic Resources (Gulf of Mexico and South Atlantic) § 622.376 Gear identification. (a)...

  14. 50 CFR 622.430 - Gear identification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Gear identification. 622.430 Section 622.430 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fishery of Puerto Rico and the U.S. Virgin Islands § 622.430 Gear identification. (a) Fish traps...

  15. 50 CFR 622.430 - Gear identification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Gear identification. 622.430 Section 622.430 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fishery of Puerto Rico and the U.S. Virgin Islands § 622.430 Gear identification. (a) Fish traps...

  16. 50 CFR 622.376 - Gear identification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Gear identification. 622.376 Section 622.376 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Migratory Pelagic Resources (Gulf of Mexico and South Atlantic) § 622.376 Gear identification. (a)...

  17. 50 CFR 665.246 - Gear identification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Gear identification. 665.246 Section 665.246 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Gear identification. In Permit Area 1, the vessel's official number must be marked legibly on all...

  18. 50 CFR 622.243 - Gear identification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Gear identification. 622.243 Section 622.243 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fishery of the South Atlantic Region § 622.243 Gear identification. (a) Golden crab traps and...

  19. Modeling Noise in Geared Transmission Systems

    NASA Astrophysics Data System (ADS)

    Subrahmanyam, C. V. S. R.

    2010-11-01

    Noise is an unwanted sound that affects human and environment if not controlled properly. In the present article an effort is made to reduce noise in geared transmission systems by modeling noise. Numerical solution methods are suggested at the end. Energy considerations in geared transmissions are discussed.

  20. The optimal design of involute gear teeth with unequal addenda

    NASA Technical Reports Server (NTRS)

    Savage, M.; Coy, J. J.; Townsend, D. P.

    1982-01-01

    The design of a gear mesh is treated with the objective of minimizing the gear size for a given gear ratio, pinion torque, pressure angle, and allowable tooth lengths. Tooth strengths considered include scoring, pitting fatigue, and bending fatigue. Kinematic involute interference is avoided. The design variation on standard spur gear teeth called the long and short addendum system, is considered. In this system the mesh center distance and pressure angle are maintained as is the ability to manufacture the teeth with standard tooling. However, the pinion and gear tooth proportions are altered in order to obtain fewer teeth numbers for the same ratio as standard gears without kinematic involute interference. The effect of this nonstandard gearing geometry with on tooth strengths and gear mesh size are studied. For a 2:1 gearing ratio, the optimal nonstandard gear design is compared with the optimal standard gear design.

  1. Analysis of Landing-Gear Behavior

    NASA Technical Reports Server (NTRS)

    Milwitzky, Benjamin; Cook, Francis E

    1953-01-01

    This report presents a theoretical study of the behavior of the conventional type of oleo-pneumatic landing gear during the process of landing impact. The basic analysis is presented in a general form and treats the motions of the landing gear prior to and subsequent to the beginning of shock-strut deflection. The applicability of the analysis to actual landing gears has been investigated for the particular case of a vertical landing gear in the absence of drag loads by comparing calculated results with experimental drop-test data for impacts with and without tire bottoming. The calculated behavior of the landing gear was found to be in good agreement with the drop-test data.

  2. HIP diffusion bonding for gear materials

    SciTech Connect

    Ashworth, M.A.; Jacobs, M.H.; Armstrong, G.R.; Freeman, R.; Rickinson, B.A.; King, S.

    1996-12-31

    Mechanical actuators used on aircraft flight control systems contain highly stressed gears which are made from low alloy steels; either through or surface hardened. Corrosion protection has traditionally been provided by cadmium plating. Conventional stainless steels, even when given surface treatments do not provide the necessary strength, wear and corrosion properties for such gears. HIP processing has been used on cobalt based alloy powders as a new approach to produce gears for mechanical and corrosion testing. The technology has been used both to consolidate the powder and HIP diffusion bond the alloy to conventional stainless steels. The microstructure and properties of the consolidated alloy are presented together with preliminary results from component testing. The diffusion bonding route has produced gears which have much better wear and corrosion resistance than conventional steel gears whilst retaining equivalent fatigue properties. The economics of the process are discussed together with the concept of using the HIP process to shape as well as consolidate the material.

  3. Vibration signature analysis of multistage gear transmission

    NASA Technical Reports Server (NTRS)

    Choy, F. K.; Tu, Y. K.; Savage, M.; Townsend, D. P.

    1989-01-01

    An analysis is presented for multistage multimesh gear transmission systems. The analysis predicts the overall system dynamics and the transmissibility to the gear box or the enclosed structure. The modal synthesis approach of the analysis treats the uncoupled lateral/torsional model characteristics of each stage or component independently. The vibration signature analysis evaluates the global dynamics coupling in the system. The method synthesizes the interaction of each modal component or stage with the nonlinear gear mesh dynamics and the modal support geometry characteristics. The analysis simulates transient and steady state vibration events to determine the resulting torque variations, speeds, changes, rotor imbalances, and support gear box motion excitations. A vibration signature analysis examines the overall dynamic characteristics of the system, and the individual model component responses. The gear box vibration analysis also examines the spectral characteristics of the support system.

  4. 6. OBLIQUE VIEW OF HOIST, SHOWING WOODEN BRAKE SHOES, REDUCTION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. OBLIQUE VIEW OF HOIST, SHOWING WOODEN BRAKE SHOES, REDUCTION GEARS AND BED FOR (MISSING) CLUTCH/DRIVE GEAR UNIT, LOOKING NORTHWEST - Buffalo Coal Mine, Vulcan Cable Hoist, Wishbone Hill, Southeast end, near Moose Creek, Sutton, Matanuska-Susitna Borough, AK

  5. K-nearest neighbors based methods for identification of different gear crack levels under different motor speeds and loads: Revisited

    NASA Astrophysics Data System (ADS)

    Wang, Dong

    2016-03-01

    Gears are the most commonly used components in mechanical transmission systems. Their failures may cause transmission system breakdown and result in economic loss. Identification of different gear crack levels is important to prevent any unexpected gear failure because gear cracks lead to gear tooth breakage. Signal processing based methods mainly require expertize to explain gear fault signatures which is usually not easy to be achieved by ordinary users. In order to automatically identify different gear crack levels, intelligent gear crack identification methods should be developed. The previous case studies experimentally proved that K-nearest neighbors based methods exhibit high prediction accuracies for identification of 3 different gear crack levels under different motor speeds and loads. In this short communication, to further enhance prediction accuracies of existing K-nearest neighbors based methods and extend identification of 3 different gear crack levels to identification of 5 different gear crack levels, redundant statistical features are constructed by using Daubechies 44 (db44) binary wavelet packet transform at different wavelet decomposition levels, prior to the use of a K-nearest neighbors method. The dimensionality of redundant statistical features is 620, which provides richer gear fault signatures. Since many of these statistical features are redundant and highly correlated with each other, dimensionality reduction of redundant statistical features is conducted to obtain new significant statistical features. At last, the K-nearest neighbors method is used to identify 5 different gear crack levels under different motor speeds and loads. A case study including 3 experiments is investigated to demonstrate that the developed method provides higher prediction accuracies than the existing K-nearest neighbors based methods for recognizing different gear crack levels under different motor speeds and loads. Based on the new significant statistical

  6. Maximum life spiral bevel reduction design

    NASA Astrophysics Data System (ADS)

    Savage, M.; Prasanna, M. G.; Coe, H. H.

    1992-07-01

    Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ratio under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed back-cone distance of the spiral bevel gear set for a specified speed ratio, shaft angle, input torque, and power. Significant parameters in the design are: the spiral angle, the pressure angle, the numbers of teeth on the pinion and gear, and the location and size of the four support bearings. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for gradient optimization. After finding the continuous optimum, a designer can analyze near optimal designs for comparison and selection. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.

  7. Maximum life spiral bevel reduction design

    NASA Technical Reports Server (NTRS)

    Savage, M.; Prasanna, M. G.; Coe, H. H.

    1992-01-01

    Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ratio under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed back-cone distance of the spiral bevel gear set for a specified speed ratio, shaft angle, input torque, and power. Significant parameters in the design are: the spiral angle, the pressure angle, the numbers of teeth on the pinion and gear, and the location and size of the four support bearings. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for gradient optimization. After finding the continuous optimum, a designer can analyze near optimal designs for comparison and selection. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.

  8. Dynamics of early planetary gear trains

    NASA Technical Reports Server (NTRS)

    August, R.; Kasuba, R.; Frater, J. L.; Pintz, A.

    1984-01-01

    A method to analyze the static and dynamic loads in a planetary gear train was developed. A variable-variable mesh stiffness (VVMS) model was used to simulate the external and internal spur gear mesh behavior, and an equivalent conventional gear train concept was adapted for the dynamic studies. The analysis can be applied either involute or noninvolute spur gearing. By utilizing the equivalent gear train concept, the developed method may be extended for use for all types of epicyclic gearing. The method is incorporated into a computer program so that the static and dynamic behavior of individual components can be examined. Items considered in the analysis are: (1) static and dynamic load sharing among the planets; (2) floating or fixed Sun gear; (3) actual tooth geometry, including errors and modifications; (4) positioning errors of the planet gears; (5) torque variations due to noninvolute gear action. A mathematical model comprised of power source, load, and planetary transmission is used to determine the instantaneous loads to which the components are subjected. It considers fluctuating output torque, elastic behavior in the system, and loss of contact between gear teeth. The dynamic model has nine degrees of freedom resulting in a set of simultaneous second order differential equations with time varying coefficients, which are solved numerically. The computer program was used to determine the effect of manufacturing errors, damping and component stiffness, and transmitted load on dynamic behavior. It is indicated that this methodology offers the designer/analyst a comprehensive tool with which planetary drives may be quickly and effectively evaluated.

  9. The Dilemma of Derelict Gear

    PubMed Central

    Scheld, A. M.; Bilkovic, D. M.; Havens, K. J.

    2016-01-01

    Every year, millions of pots and traps are lost in crustacean fisheries around the world. Derelict fishing gear has been found to produce several harmful environmental and ecological effects, however socioeconomic consequences have been investigated less frequently. We analyze the economic effects of a substantial derelict pot removal program in the largest estuary of the United States, the Chesapeake Bay. By combining spatially resolved data on derelict pot removals with commercial blue crab (Callinectes sapidus) harvests and effort, we show that removing 34,408 derelict pots led to significant gains in gear efficiency and an additional 13,504 MT in harvest valued at US $21.3 million—a 27% increase above that which would have occurred without removals. Model results are extended to a global analysis where it is seen that US $831 million in landings could be recovered annually by removing less than 10% of the derelict pots and traps from major crustacean fisheries. An unfortunate common pool externality, the degradation of marine environments is detrimental not only to marine organisms and biota, but also to those individuals and communities whose livelihoods and culture depend on profitable and sustainable marine resource use. PMID:26790394

  10. The Dilemma of Derelict Gear.

    PubMed

    Scheld, A M; Bilkovic, D M; Havens, K J

    2016-01-21

    Every year, millions of pots and traps are lost in crustacean fisheries around the world. Derelict fishing gear has been found to produce several harmful environmental and ecological effects, however socioeconomic consequences have been investigated less frequently. We analyze the economic effects of a substantial derelict pot removal program in the largest estuary of the United States, the Chesapeake Bay. By combining spatially resolved data on derelict pot removals with commercial blue crab (Callinectes sapidus) harvests and effort, we show that removing 34,408 derelict pots led to significant gains in gear efficiency and an additional 13,504 MT in harvest valued at US $21.3 million--a 27% increase above that which would have occurred without removals. Model results are extended to a global analysis where it is seen that US $831 million in landings could be recovered annually by removing less than 10% of the derelict pots and traps from major crustacean fisheries. An unfortunate common pool externality, the degradation of marine environments is detrimental not only to marine organisms and biota, but also to those individuals and communities whose livelihoods and culture depend on profitable and sustainable marine resource use.

  11. The Dilemma of Derelict Gear

    NASA Astrophysics Data System (ADS)

    Scheld, A. M.; Bilkovic, D. M.; Havens, K. J.

    2016-01-01

    Every year, millions of pots and traps are lost in crustacean fisheries around the world. Derelict fishing gear has been found to produce several harmful environmental and ecological effects, however socioeconomic consequences have been investigated less frequently. We analyze the economic effects of a substantial derelict pot removal program in the largest estuary of the United States, the Chesapeake Bay. By combining spatially resolved data on derelict pot removals with commercial blue crab (Callinectes sapidus) harvests and effort, we show that removing 34,408 derelict pots led to significant gains in gear efficiency and an additional 13,504 MT in harvest valued at US $21.3 million—a 27% increase above that which would have occurred without removals. Model results are extended to a global analysis where it is seen that US $831 million in landings could be recovered annually by removing less than 10% of the derelict pots and traps from major crustacean fisheries. An unfortunate common pool externality, the degradation of marine environments is detrimental not only to marine organisms and biota, but also to those individuals and communities whose livelihoods and culture depend on profitable and sustainable marine resource use.

  12. Helical Face Gear Development Under the Enhanced Rotorcraft Drive System Program

    NASA Technical Reports Server (NTRS)

    Heath, Gregory F.; Slaughter, Stephen C.; Fisher, David J.; Lewicki, David G.; Fetty, Jason

    2011-01-01

    U.S. Army goals for the Enhanced Rotorcraft Drive System Program are to achieve a 40 percent increase in horsepower to weight ratio, a 15 dB reduction in drive system generated noise, 30 percent reduction in drive system operating, support, and acquisition cost, and 75 percent automatic detection of critical mechanical component failures. Boeing s technology transition goals are that the operational endurance level of the helical face gearing and related split-torque designs be validated to a TRL 6, and that analytical and manufacturing tools be validated. Helical face gear technology is being developed in this project to augment, and transition into, a Boeing AH-64 Block III split-torque face gear main transmission stage, to yield increased power density and reduced noise. To date, helical face gear grinding development on Northstar s new face gear grinding machine and pattern-development tests at the NASA Glenn/U.S. Army Research Laboratory have been completed and are described.

  13. Effects of Planetary Speed Reduction Ratio on Mean Service Life

    NASA Technical Reports Server (NTRS)

    Savage, M.; Rubadeux, K. L.; Coe, H. H.

    1998-01-01

    Planetary gear transmissions are compact speed reductions which use parallel-load paths to transmit high power. The range of possible reduction ratios is bounded from below and above by limits on the relative size of the planet gears. For a single plane planetary transmission, the speed-reduction ratio must be greater than two for planet gears to exist. As the ratio increase, so does the size of the planets relative to the sizes of the sun and ring. Which ratio is best for a planetary reduction can be resolved by studying a series of optimal designs. In this series, each design is obtained by maximizing the service life for a spur-gear planetary with a fixed size, speed reduction ratio, input speed, power and materials. The planetary gear reduction service life is modeled as a function of the two-parameter Weibull distributed service lives of the ball bearings and spur gears in the reduction. Planet-bearing life strongly influences the optimal reduction lives which point to an optimal planetary reduction ratio in the neighborhood of four to five.

  14. Dynamic simulation of planetary gear set with flexible spur ring gear

    NASA Astrophysics Data System (ADS)

    Chen, Zaigang; Shao, Yimin; Su, Daizhong

    2013-12-01

    Ring gear is a key element for vibration transmission and noise radiation in the planetary gear system which has been widely employed in different areas, such as wind turbine transmissions. Its flexibility has a great influence on the mesh stiffness of internal gear pair and the dynamic response of the planetary gear system, especially for the thin ring cases. In this paper, the flexibility of the internal ring gear is considered based on the uniformly curved Timoshenko beam theory. The ring deformation is coupled into the mesh stiffness model, which enables the investigation on the effects of the ring flexibility on the mesh stiffness and the dynamic responses of the planetary gear. A method about how to synthesize the total mesh stiffness of the internal gear pairs in multi-tooth region together with the ring deformation and the tooth errors is proposed. Numerical results demonstrate that the ring thickness has a great impact on the shape and magnitude of the mesh stiffness of the internal gear pair. It is noted that the dynamic responses of the planetary gear set with equally spaced supports for the ring gear are modulated due to the cyclic variation of the mesh stiffness resulted from the presence of the supports, which adds more complexity in the frequency structure.

  15. Control of gear shifts in dual clutch transmission powertrains

    NASA Astrophysics Data System (ADS)

    Walker, Paul D.; Zhang, Nong; Tamba, Richard

    2011-08-01

    To achieve the best possible responses during shifting in dual clutch transmissions it is commonplace to integrate clutch and engine control, while the clutch is used to match speeds between the engine and wheels via reduction gears, poor engine control can lead to extended engagement times and rough/harsh shift transients. This paper proposes a method for combined speed and torque control of vehicle powertrains with dual clutch transmissions for both the engine and clutches. The vehicle powertrain is modelled as a simple four degree of freedom system with reduction gears and two clutches. Including a detailed clutch hydraulic model, comprising of the direct acting solenoids and clutch piston with the hydraulic fluid modelled as a compressible fluid. Powertrain control is realised through control of clutch solenoids and manipulation of the engine throttle input. Sensitivity study of clutch performance evaluating inaccurate torque estimation demonstrated variance in the response of the hydraulic system, with an indicative simulation of poor estimation resulting in increased powertrain vibration during and after shifting. Simulations are conducted to demonstrate the capacity for this method of engine and clutch control to further reduce shift transients developed in dual clutch transmission powertrains. The obtained results also show that the adoption of torque based control techniques for both the clutch and engine, which makes use of the estimated target clutch torque, significantly improves the powertrain response as a result of reduction in the lockup discontinuities.

  16. The application of elastohydrodynamic lubrication in gear tooth contacts

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.

    1972-01-01

    An analytical method is presented for determining elastohydrodynamic film thickness in gears from theory and how the film affects gear failure and life. The practical aspects of gear lubrication are presented, including mechanical and service variables which must be considered to obtain optimum gear performance under severe operating conditions.

  17. Calculation of the efficiency of aircraft gear drives

    NASA Astrophysics Data System (ADS)

    Shatalov, B. I.

    Expressions are presented for determining the efficiency of helical, spur, and beveled gear drives. It is shown that losses in the gearing increase significantly with the decreasing number of teeth; the efficiency of external gears is less than that of internal gears. A formula for determining friction losses is included.

  18. 50 CFR 660.211 - Fixed gear fishery-definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Fixed gear fishery-definitions. 660.211... Groundfish-Limited Entry Fixed Gear Fisheries § 660.211 Fixed gear fishery—definitions. These definitions are specific to the limited entry fixed gear fisheries covered in this subpart. General groundfish...

  19. 50 CFR 600.510 - Gear avoidance and disposal.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Gear avoidance and disposal. 600.510... Gear avoidance and disposal. (a) Vessel and gear avoidance. (1) FFV's arriving on fishing grounds where fishing vessels are already fishing or have set their gear for that purpose must ascertain the...

  20. 14 CFR 25.1515 - Landing gear speeds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear speeds. 25.1515 Section 25... Limitations § 25.1515 Landing gear speeds. (a) The established landing gear operating speed or speeds, V LO, may not exceed the speed at which it is safe both to extend and to retract the landing gear,...

  1. 14 CFR 23.477 - Landing gear arrangement.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing gear arrangement. 23.477 Section 23....477 Landing gear arrangement. Sections 23.479 through 23.483, or the conditions in appendix C, apply to airplanes with conventional arrangements of main and nose gear, or main and tail gear....

  2. 14 CFR 23.477 - Landing gear arrangement.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Landing gear arrangement. 23.477 Section 23....477 Landing gear arrangement. Sections 23.479 through 23.483, or the conditions in appendix C, apply to airplanes with conventional arrangements of main and nose gear, or main and tail gear....

  3. 14 CFR 23.477 - Landing gear arrangement.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Landing gear arrangement. 23.477 Section 23....477 Landing gear arrangement. Sections 23.479 through 23.483, or the conditions in appendix C, apply to airplanes with conventional arrangements of main and nose gear, or main and tail gear....

  4. 46 CFR 58.25-20 - Piping for steering gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  5. 50 CFR 660.211 - Fixed gear fishery-definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Fixed gear fishery-definitions. 660.211... Groundfish-Limited Entry Fixed Gear Fisheries § 660.211 Fixed gear fishery—definitions. These definitions are specific to the limited entry fixed gear fisheries covered in this subpart. General groundfish...

  6. 50 CFR 660.211 - Fixed gear fishery-definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Fixed gear fishery-definitions. 660.211... Groundfish-Limited Entry Fixed Gear Fisheries § 660.211 Fixed gear fishery—definitions. These definitions are specific to the limited entry fixed gear fisheries covered in this subpart. General groundfish...

  7. 50 CFR 660.211 - Fixed gear fishery-definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Fixed gear fishery-definitions. 660.211... Groundfish-Limited Entry Fixed Gear Fisheries § 660.211 Fixed gear fishery—definitions. These definitions are specific to the limited entry fixed gear fisheries covered in this subpart. General groundfish...

  8. 14 CFR 25.1515 - Landing gear speeds.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Landing gear speeds. 25.1515 Section 25... Limitations § 25.1515 Landing gear speeds. (a) The established landing gear operating speed or speeds, V LO, may not exceed the speed at which it is safe both to extend and to retract the landing gear,...

  9. 46 CFR 58.25-20 - Piping for steering gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  10. 14 CFR 23.477 - Landing gear arrangement.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Landing gear arrangement. 23.477 Section 23....477 Landing gear arrangement. Sections 23.479 through 23.483, or the conditions in appendix C, apply to airplanes with conventional arrangements of main and nose gear, or main and tail gear....

  11. 46 CFR 108.641 - Instructions for changing steering gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary...

  12. 50 CFR 600.510 - Gear avoidance and disposal.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Gear avoidance and disposal. 600.510... Gear avoidance and disposal. (a) Vessel and gear avoidance. (1) FFV's arriving on fishing grounds where fishing vessels are already fishing or have set their gear for that purpose must ascertain the...

  13. 14 CFR 25.1515 - Landing gear speeds.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Landing gear speeds. 25.1515 Section 25... Limitations § 25.1515 Landing gear speeds. (a) The established landing gear operating speed or speeds, V LO, may not exceed the speed at which it is safe both to extend and to retract the landing gear,...

  14. 46 CFR 58.25-20 - Piping for steering gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  15. 50 CFR 600.510 - Gear avoidance and disposal.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Gear avoidance and disposal. 600.510... Gear avoidance and disposal. (a) Vessel and gear avoidance. (1) FFV's arriving on fishing grounds where fishing vessels are already fishing or have set their gear for that purpose must ascertain the...

  16. 29 CFR 1919.31 - Proof tests-loose gear.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Proof tests-loose gear. 1919.31 Section 1919.31 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.31 Proof tests—loose gear. (a) Chains, rings, shackles and other loose gear...

  17. 46 CFR 58.25-20 - Piping for steering gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  18. 49 CFR 230.77 - Foundation brake gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Foundation brake gear. 230.77 Section 230.77... Tenders Brake and Signal Equipment § 230.77 Foundation brake gear. (a) Maintenance. Foundation brake gear...) Distance above the rails. No part of the foundation brake gear of the steam locomotive or tender shall...

  19. 49 CFR 230.77 - Foundation brake gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Foundation brake gear. 230.77 Section 230.77... Tenders Brake and Signal Equipment § 230.77 Foundation brake gear. (a) Maintenance. Foundation brake gear...) Distance above the rails. No part of the foundation brake gear of the steam locomotive or tender shall...

  20. 29 CFR 1919.31 - Proof tests-loose gear.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Proof tests-loose gear. 1919.31 Section 1919.31 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.31 Proof tests—loose gear. (a) Chains, rings, shackles and other loose gear...

  1. 14 CFR 25.1515 - Landing gear speeds.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Landing gear speeds. 25.1515 Section 25... Limitations § 25.1515 Landing gear speeds. (a) The established landing gear operating speed or speeds, V LO, may not exceed the speed at which it is safe both to extend and to retract the landing gear,...

  2. 46 CFR 108.641 - Instructions for changing steering gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary...

  3. 49 CFR 230.77 - Foundation brake gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Foundation brake gear. 230.77 Section 230.77... Tenders Brake and Signal Equipment § 230.77 Foundation brake gear. (a) Maintenance. Foundation brake gear...) Distance above the rails. No part of the foundation brake gear of the steam locomotive or tender shall...

  4. 29 CFR 1919.31 - Proof tests-loose gear.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Proof tests-loose gear. 1919.31 Section 1919.31 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.31 Proof tests—loose gear. (a) Chains, rings, shackles and other loose gear...

  5. 50 CFR 622.31 - Buoy gear identification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Buoy gear identification. 622.31 Section... Resources of the Gulf of Mexico § 622.31 Buoy gear identification. (a) Buoy gear. In the Gulf EEZ, if buoy gear is used or possessed, each buoy must display the official number of the vessel. See § 622.2...

  6. 50 CFR 622.31 - Buoy gear identification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Buoy gear identification. 622.31 Section... Resources of the Gulf of Mexico § 622.31 Buoy gear identification. (a) Buoy gear. In the Gulf EEZ, if buoy gear is used or possessed, each buoy must display the official number of the vessel. See § 622.2...

  7. 46 CFR 108.641 - Instructions for changing steering gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary...

  8. 14 CFR 25.1515 - Landing gear speeds.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Landing gear speeds. 25.1515 Section 25... Limitations § 25.1515 Landing gear speeds. (a) The established landing gear operating speed or speeds, V LO, may not exceed the speed at which it is safe both to extend and to retract the landing gear,...

  9. 29 CFR 1919.31 - Proof tests-loose gear.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Proof tests-loose gear. 1919.31 Section 1919.31 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.31 Proof tests—loose gear. (a) Chains, rings, shackles and other loose gear...

  10. 49 CFR 230.77 - Foundation brake gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Foundation brake gear. 230.77 Section 230.77... Tenders Brake and Signal Equipment § 230.77 Foundation brake gear. (a) Maintenance. Foundation brake gear...) Distance above the rails. No part of the foundation brake gear of the steam locomotive or tender shall...

  11. 14 CFR 23.477 - Landing gear arrangement.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Landing gear arrangement. 23.477 Section 23....477 Landing gear arrangement. Sections 23.479 through 23.483, or the conditions in appendix C, apply to airplanes with conventional arrangements of main and nose gear, or main and tail gear....

  12. 46 CFR 58.25-20 - Piping for steering gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  13. 29 CFR 1919.31 - Proof tests-loose gear.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Proof tests-loose gear. 1919.31 Section 1919.31 Labor... (CONTINUED) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.31 Proof tests—loose gear. (a) Chains, rings, shackles and other loose gear...

  14. 49 CFR 230.77 - Foundation brake gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Foundation brake gear. 230.77 Section 230.77... Tenders Brake and Signal Equipment § 230.77 Foundation brake gear. (a) Maintenance. Foundation brake gear...) Distance above the rails. No part of the foundation brake gear of the steam locomotive or tender shall...

  15. 50 CFR 622.46 - Prevention of gear conflicts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Prevention of gear conflicts. 622.46... Management Measures § 622.46 Prevention of gear conflicts. (a) No person may knowingly place in the Gulf EEZ... zones for shrimp trawling and the use of fixed gear to prevent gear conflicts. Necessary prohibitions...

  16. 50 CFR 622.46 - Prevention of gear conflicts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Prevention of gear conflicts. 622.46... Management Measures § 622.46 Prevention of gear conflicts. (a) No person may knowingly place in the Gulf EEZ... zones for shrimp trawling and the use of fixed gear to prevent gear conflicts. Necessary prohibitions...

  17. 50 CFR 622.59 - Prevention of gear conflicts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Prevention of gear conflicts. 622.59... ATLANTIC Shrimp Fishery of the Gulf of Mexico § 622.59 Prevention of gear conflicts. (a) No person may... zones for shrimp trawling and the use of fixed gear to prevent gear conflicts. Necessary prohibitions...

  18. Flexible universal gear box system with yokes

    SciTech Connect

    Giocastro, J.; Giocastro, S.

    1987-01-20

    This patent describes a flexible joint system associated with the front and rear portions of a motor vehicle, comprising, in combination: a generally horizontal pivot member, a pair of opposed first and second yoke means rotatably connected to the pivot member the first yoke means being secured to the front portion of the vehicle and the second yoke means being secured to the rear portion of the vehicle. The final and second yoke means are movable relative to one another, a generally horizontal shaft member rotatably connected to and transversely passing through the first yoke means and disposed approximately perpendicular to the pivot member, first bevel gear means secured to the pivot member between the first and second yoke means, second bevel gear means perpendicular and meshing with the first bevel gear means and secured to the shaft member, and the second yoke means being for rotating about the pivot member relative to the first yoke means and for rotating the second bevel gear means relative to the first bevel gear means in response to movement of the rear portion of the motor vehicle. The first yoke means is for rotating about the pivot member relative to and for rotating the first bevel gear means relative to the second bevel gear means in response to movement of the front portion of the motor vehicle.

  19. How automatic is manual gear shifting?

    PubMed

    Shinar, D; Meir, M; Ben-Shoham, I

    1998-12-01

    Manual gear shifting is often used as an example of an automated (vs. controlled) process in driving. The present study provided an empirical evaluation of this assumption by evaluating sign detection and recall performance of novice and experienced drivers driving manual shift and automatic transmission cars in a downtown area requiring frequent gear shifting. The results showed that manual gear shifting significantly impaired sign detection performance of novice drivers using manual gears compared with novice drivers using an automatic transmission, whereas no such differences existed between the two transmission types for experienced drivers. The results clearly demonstrate that manual gear shifting is a complex psychomotor skill that is not easily (or quickly) automated and that until it becomes automated, it is an attention-demanding task that may impair other monitoring aspects of driving performance. Actual or potential applications of this research include a reevaluation of the learning process in driving and the need for phased instruction in driving from automatic gears to manual gears.

  20. A Parametric Study of Spur Gear Dynamics

    NASA Technical Reports Server (NTRS)

    Lin, Hsiang Hsi; Liou, Chuen-Huei

    1998-01-01

    A parametric study of a spur gear system was performed through a numerical analysis approach. This study used the gear dynamic program DANST, a computer simulator, to determine the dynamic behavior of a spur gear system. The analytical results have taken the deflection of shafts and bearings into consideration for static analysis, and the influence of these deflections on gear dynamics was investigated. Damping in the gear system usually is an unknown quantity, but it has an important effect in resonance vibration. Typical values as reported in the literature were used in the present analysis. The dynamic response due to different damping factors was evaluated and compared. The effect of the contact ratio on spur gear dynamic load and dynamic stress was investigated through a parameter study. The contact ratio was varied over the range of 1.26 to 2.46 by adjusting the tooth addendum. Gears with contact ratio near 2.0 were found to have the most favorable dynamic performance.

  1. Apparatus for controlling transmission gear shift selection

    SciTech Connect

    Bailey, T.M.

    1986-07-29

    In an automotive engine having an electrical power source and an automatic or semi-automatic transmission including a manually operated transmission gear shift lever having at least two forward drive positions, an apparatus is described which consists of: (a) a speed sensing means for sensing the rotation speed of the engine and generating an output signal when the engine reaches a preselected rotational speed; and (b) a gear shifting means for changing the shift positions of the gear shift lever from a first drive position to a second drive position automatically in response to the output signal from the speed sensing means, the gear shifting means including (i) a latch actuable between open and closed positions, (ii) a normally de-energized solenoid having a plunger connected to the latch and operable to move the latch to the open position when the solenoid is energized by the electrical power source, (iii) a relay means for allowing the energizing of the solenoid by the power source in response to the output signal from the speed sensing means, and (iv) an actuating means, including a spring biased linkage mechanism operably connected to the gear shift lever and the latch, for actuating the movement of the gear shift lever from the first drive position to the second drive position in response to movement of the latch from the closed to the open position, thereby causing gear shifting to occur when the engine reaches the preselected rotational speed.

  2. Multi-angle pinion and gear power transmission

    SciTech Connect

    Hart, F.M.

    1986-02-04

    This patent describes a worm and gear power transmission which consists of a housing, an input shaft, two axially aligned, different ratio worms formed on the input shaft in the housing. It also includes a pair of gears spaced apart in the housing such that a first gear of the pair meshes with one of the worms, and a second gear of the pair meshes with the other worm, the first and second gears positioned such that planes through the gears and the axis of the input shaft are at a right angle to one another, and output shafts extending out of the housing from the respective gears.

  3. Efficiency of nonstandard and high contact ratio involute spur gears

    NASA Technical Reports Server (NTRS)

    Anderson, N. E.; Loewenthal, S. H.

    1984-01-01

    A power loss prediction was extended to include involute spur gears of nonstandard proportions. The method is used to analyze the effects of modified addendum, tooth thickness, and gear center distance in addition to the parameters previously considered which included gear diameter, pitch, pressure angle, face width, oil viscosity, speed, and torque. Particular emphasis was placed on high contact ratio gearing (contact ratios greater than two). Despite their higher sliding velocities, high contact ratio gears are designed to levels of efficiency comparable to those of conventional gears while retaining their advantages through proper selection of gear geometry.

  4. Efficiency of nonstandard and high contact ratio involute spur gears

    NASA Technical Reports Server (NTRS)

    Anderson, N. E.; Loewenthal, S. H.

    1986-01-01

    A power loss prediction was extended to include involute spur gears of nonstandard proportions. The method is used to analyze the effects of modified addendum, tooth thickness, and gear center distance in addition to the parameters previously considered which included gear diameter, pitch, pressure angle, face width, oil viscosity, speed, and torque. Particular emphasis was placed on high contact ratio gearing (contact ratios greater than two). Despite their higher sliding velocities, high contact ratio gears are designed to levels of efficiency comparable to those of conventional gears while retaining their advantages through proper selection of gear geometry.

  5. High Speed Gear Sized and Configured to Reduce Windage Loss

    NASA Technical Reports Server (NTRS)

    Kunz, Robert F. (Inventor); Medvitz, Richard B. (Inventor); Hill, Matthew John (Inventor)

    2013-01-01

    A gear and drive system utilizing the gear include teeth. Each of the teeth has a first side and a second side opposite the first side that extends from a body of the gear. For each tooth of the gear, a first extended portion is attached to the first side of the tooth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates. The gear may be utilized in drive systems that may have high rotational speeds, such as speeds where the tip velocities are greater than or equal to about 68 m/s. Some embodiments of the gear may also utilize teeth that also have second extended portions attached to the second sides of the teeth to divert flow of fluid adjacent to the body of the gear to reduce windage losses that occur when the gear rotates.

  6. Performance improvement of magnetic gear and efficiency comparison with conventional mechanical gear

    NASA Astrophysics Data System (ADS)

    Nakamura, Kenji; Fukuoka, Michinari; Ichinokura, Osamu

    2014-05-01

    Magnetic gears can transmit torque without any mechanical contact. Hence, they have low vibration, no wear, and fatigue, which ensure maintenance-free operation. There are various types of magnetic gears. Among them, a planetary type magnetic gear, which consists of coaxial inner and outer rotors with surface-mounted permanent magnet and ferromagnetic stationary parts called pole-pieces, has recently attracted interest since it offers higher torque than other type magnetic gears. This paper presents a comprehensive investigation of the influence of geometry and position of the pole-pieces on torque characteristic based on finite element analysis and experiment. Surveyed parameters of the pole-pieces include lengths in the radial and axial directions and position in the radial direction. Finally, it is demonstrated that the maximum torque of the improved prototype magnetic gear is increased by 45% and the maximum efficiency achieves up to about 99%, which is equal to or more than a conventional planetary type mechanical gear.

  7. Estimation of gear tooth transverse crack size from vibration by fusing selected gear condition indices

    NASA Astrophysics Data System (ADS)

    Choi, Sukhwan; Li, C. James

    2006-09-01

    Gears are common power transmission elements and are frequently responsible for transmission failures. Since a tooth crack is not directly measurable while a gear is in operation, one has to develop an indirect method to estimate its size from some measurables. This study developed such a method to estimate the size of a tooth transverse crack for a spur gear in operation. Using gear vibrations measured from an actual gear accelerated test, this study examined existing gear condition indices to identify those correlated well to crack size and established their utility for crack size estimation through index fusion using a neural network. When tested with vibrations measured from another accelerated test, the method had an averaged estimation error of about 5%.

  8. Gear fatigue crack prognosis using embedded model, gear dynamic model and fracture mechanics

    NASA Astrophysics Data System (ADS)

    Li, C. James; Lee, Hyungdae

    2005-07-01

    This paper presents a model-based method that predicts remaining useful life of a gear with a fatigue crack. The method consists of an embedded model to identify gear meshing stiffness from measured gear torsional vibration, an inverse method to estimate crack size from the estimated meshing stiffness; a gear dynamic model to simulate gear meshing dynamics and determine the dynamic load on the cracked tooth; and a fast crack propagation model to forecast the remaining useful life based on the estimated crack size and dynamic load. The fast crack propagation model was established to avoid repeated calculations of FEM and facilitate field deployment of the proposed method. Experimental studies were conducted to validate and demonstrate the feasibility of the proposed method for prognosis of a cracked gear.

  9. NASA Orbiter Extended Nose Landing Gear

    NASA Technical Reports Server (NTRS)

    King, Steven R.; Jensen, Scott A.; Hansen, Christopher P.

    1999-01-01

    This paper discusses the design, development, test, and evaluation of a prototype Extended Nose Landing Gear (ENLG) for NASA's Space Shuttle orbiters. The ENLG is a proposed orbiter modification developed in-house at NASA's Johnson Space Center (JSC) by a joint government/industry team. It increases the orbiter's nose landing gear (NLG) length, thereby changing the vehicle's angle of attack during rollout, which lowers the aerodynamic forces on the vehicle. This, in combination with a dynamic elevon change, will lower the loads on the orbiter's main landing gear (MLG). The extension is accomplished by adding a telescoping section to the current NLG strut that will be pneumatically extended during NLG deployment.

  10. Engagement of Metal Debris into Gear Mesh

    NASA Technical Reports Server (NTRS)

    handschuh, Robert F.; Krantz, Timothy L.

    2010-01-01

    A series of bench-top experiments was conducted to determine the effects of metallic debris being dragged through meshing gear teeth. A test rig that is typically used to conduct contact fatigue experiments was used for these tests. Several sizes of drill material, shim stock and pieces of gear teeth were introduced and then driven through the meshing region. The level of torque required to drive the "chip" through the gear mesh was measured. From the data gathered, chip size sufficient to jam the mechanism can be determined.

  11. Roller/Gear Drives For Robotic Manipulators

    NASA Technical Reports Server (NTRS)

    Anderson, William J.; Shipitalo, William

    1995-01-01

    Pitch/yaw roller/gear drive and wrist-roll roller/gear drive designed to incorporate several features desirable in robotic-joint actuators. Includes zero backlash, high efficiency, smooth motion (little ripple in torque and in speed ratio), and high degree of back-drivability. Pitch/yaw drive is novel two-axis drive containing combination of gears, rollers, and springs acting together eliminating backlash and cogging. Wrist-roll drive more-conventional single-axis drive offering advantages like those of pitch/yaw drive.

  12. An Integrated Approach for Gear Health Prognostics

    NASA Technical Reports Server (NTRS)

    He, David; Bechhoefer, Eric; Dempsey, Paula; Ma, Jinghua

    2012-01-01

    In this paper, an integrated approach for gear health prognostics using particle filters is presented. The presented method effectively addresses the issues in applying particle filters to gear health prognostics by integrating several new components into a particle filter: (1) data mining based techniques to effectively define the degradation state transition and measurement functions using a one-dimensional health index obtained by whitening transform; (2) an unbiased l-step ahead RUL estimator updated with measurement errors. The feasibility of the presented prognostics method is validated using data from a spiral bevel gear case study.

  13. Motor vehicle differential gear housing

    SciTech Connect

    Bitcon, L.L.

    1990-06-12

    This patent describes a motor vehicle differential gear housing. It comprises: a substantially box shaped casing having an interior and exterior defined by front, rear, top, bottom and two side panels, the front and rear panels each having an aperture, the apertures being at least partially in axial alignment; first bearing means cooperating with the apertures and demountably secured to each of the front and rear panels. The first bearing means is aligned coaxially with the aligned portions of the apertures; the side panels each having an opening, the openings being at least partially in axial alignment; axle support bearing housings aligned coaxially with the aligned portions of the openings on the side panels and threadedly mounted therein and adapted to have driving axles journaled in second bearing means in the bearing housings; and at least the front and rear panels being removably attached to the side panels.

  14. Production Laser Welding Of Gears

    NASA Astrophysics Data System (ADS)

    Guastaferri, David

    1986-11-01

    With the greater acceptance of laser technology as a viable alternative to traditional metals joining methods, the need has arisen to integrate lasers into efficient high production systems. This paper will describe one such system which is dedicated to the automated processing and laser welding of automotive transmission gear components. The system features two (2) 6 KW CO2 lasers, automated part manipulation, vapor degreasers, air cylinder press stations, fully enclosed weld stations incorporating bottom delivery methods, and programmable computer control which allows complete monitoring throughout the entire production cycle. It is the intent of this paper to describe all segments of the system in detail as to design, manufacture, and integration. Concerning this specific application, an overview from initial inquiry through final installation of the manufactured system will be presented and will focus on the laser welding process and parameter development as it relates to the total systems concept and production goals.

  15. Straddle Design Of Spiral Bevel And Hypoid Gears

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Litvin, Faydor L.; Kuan, Chihping; Kieffer, Jonathan; Bossler, Robert

    1994-01-01

    Computer-assisted method of analysis of straddle designs for spiral bevel and hypoid gears helps prevent undercutting of gear shafts during cutting of gear teeth. Analytical method and computer program based on equations for surface traced out by motion of head cutter, equation for cylindrical surface of shaft, and equations expressing relationships among coordinate systems fixed to various components of gear-cutting machine tool and gear.

  16. Dynamic Forces in Spur Gears - Measurement, Prediction, and Code Validation

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.; Townsend, Dennis P.; Rebbechi, Brian; Lin, Hsiang Hsi

    1996-01-01

    Measured and computed values for dynamic loads in spur gears were compared to validate a new version of the NASA gear dynamics code DANST-PC. Strain gage data from six gear sets with different tooth profiles were processed to determine the dynamic forces acting between the gear teeth. Results demonstrate that the analysis code successfully simulates the dynamic behavior of the gears. Differences between analysis and experiment were less than 10 percent under most conditions.

  17. Surface micromachined microengine as the driver for micromechanical gears

    SciTech Connect

    Garcia, E.J.; Sniegowski, J.J.

    1995-05-01

    The transmission of mechanical power is often accomplished through the use of gearing. The recently developed surface micromachined microengine provides us with an actuator which is suitable for driving surface micromachined geared systems. In this paper we will present aspects of the microengine as they relate to the driving of geared mechanisms, issues relating to the design of micro gear mechanisms, and details of a design of a microengine-driven geared shutter mechanism.

  18. Gear noise behavior induced by their topological quality

    NASA Astrophysics Data System (ADS)

    Jolivet, S.; Mezghani, S.; El Mansori, M.; Zahouani, H.

    2014-01-01

    The upcoming fuel economy standards will result in the rapid development of electric or hybrid vehicles. Such regulatory demands will affect transmission design, which is currently driving changes in the number, type, size and quality levels of gears. Thus, gear manufacturers need to create high quality gear flanks with special topological modifications. The most important objectives are to increase the load-carrying capacity of gears and also to reduce the gear noise behavior. The teeth surface is at the heart of gear meshing mechanics and is one of the main elements in the generation of noise. The most common gear wear mechanisms are micro-pitting, pitting and spalling, which often occur on teeth surface during the early stage of failure. This study aims to identify the scale effect of pitting defects of gear teeth surface on the acoustics response of a spur gear pair. Consequently, we have developed a two-dimensional finite-element simulation model of a one-stage gear system. The transmission system was composed of two identical spur gears with one degree of freedom. Pitting defects versus topological features at different scales were modeled on the gear tooth flanks. To quantify their impact on gear noises and vibrations, we used contact stiffness as our criteria because it is directly linked to gear noise. The prevalence of the gear quality and its topological features on power density and sound issues are computed and discussed in this paper.

  19. Influence of landing gear flexibility on aircraft performance during ground roll

    NASA Technical Reports Server (NTRS)

    Sivaramakrishnan, M. M.

    1981-01-01

    An analysis is made of the influence of landing gear deflection characteristics on aircraft performance on the ground up to rotation. A quasi-steady dynamic equilibrium state is assumed, including other simplifying assumptions such as calm air conditions and normal aircraft lift and drag. Ground incidence is defined as the angle made by the mean aerodynamic chord of the wing with respect to the ground plane, and equations are given for force and balance which determine the quasi-equilibrium conditions for the aircraft during ground roll. Results indicate that the landing gear deflections lead to a substantial increase in the angle of attack, and the variation in the ground incidence due to landing gear flexibility could be as much as + or - 50%, and the reduction in tail load requirements almost 25%.

  20. Systems and Methods for Implementing Bulk Metallic Glass-Based Strain Wave Gears and Strain Wave Gear Components

    NASA Technical Reports Server (NTRS)

    Hofmann, Douglas C. (Inventor); Wilcox, Brian (Inventor)

    2016-01-01

    Bulk metallic glass-based strain wave gears and strain wave gear components. In one embodiment, a strain wave gear includes: a wave generator; a flexspline that itself includes a first set of gear teeth; and a circular spline that itself includes a second set of gear teeth; where at least one of the wave generator, the flexspline, and the circular spline, includes a bulk metallic glass-based material.

  1. New Geometry of Worm Face Gear Drives with Conical and Cylindrical Worms: Generation, Simulation of Meshing, and Stress Analysis

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Nava, Alessandro; Fan, Qi; Fuentes, Alfonso

    2002-01-01

    New geometry of face worm gear drives with conical and cylindrical worms is proposed. The generation of the face worm-gear is based on application of a tilted head-cutter (grinding tool) instead of application of a hob applied at present. The generation of a conjugated worm is based on application of a tilted head-cutter (grinding tool) as well. The bearing contact of the gear drive is localized and is oriented longitudinally. A predesigned parabolic function of transmission errors for reduction of noise and vibration is provided. The stress analysis of the gear drive is performed using a three-dimensional finite element analysis. The contacting model is automatically generated. The developed theory is illustrated with numerical examples.

  2. Computerized Generation and Simulation of Meshing and Contact of New Type of Novikov-Wildhaber Helical Gears

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Feng, Pin-Hao; Lagutin, Sergei A.

    2000-01-01

    In this report, we propose a new geometry for low-noise, increased-strength helical gears of the Novikov-Wildhaber type. Contact stresses are reduced as a result of their convex-concave gear tooth surfaces. The gear tooth surfaces are crowned in the profile direction to localize bearing contact and in the longitudinal direction to obtain a parabolic function of transmission errors. Such a function results in the reduction of noise and vibrations. Methods for the generation of the proposed gear tooth surfaces by grinding and hobbing are considered, and a tooth contact analysis (TCA) computer program to simulate meshing and contact is applied. The report also investigates the influence of misalignment on transmission errors and shift of bearing contact. Numerical examples to illustrate the developed approaches are proposed. The proposed geometry was patented by Ford/UIC (Serial Number 09-340-824, pending) on June 28, 1999.

  3. 50 CFR 300.109 - Gear disposal.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... articles and substances include, but are not limited to, fishing gear, net scraps, bale straps, plastic bags, oil drums, petroleum containers, oil, toxic chemicals or any manmade items retrieved in...

  4. Vibration Based Sun Gear Damage Detection

    NASA Technical Reports Server (NTRS)

    Hood, Adrian; LaBerge, Kelsen; Lewicki, David; Pines, Darryll

    2013-01-01

    Seeded fault experiments were conducted on the planetary stage of an OH-58C helicopter transmission. Two vibration based methods are discussed that isolate the dynamics of the sun gear from that of the planet gears, bearings, input spiral bevel stage, and other components in and around the gearbox. Three damaged sun gears: two spalled and one cracked, serve as the focus of this current work. A non-sequential vibration separation algorithm was developed and the resulting signals analyzed. The second method uses only the time synchronously averaged data but takes advantage of the signal/source mapping required for vibration separation. Both algorithms were successful in identifying the spall damage. Sun gear damage was confirmed by the presence of sun mesh groups. The sun tooth crack condition was inconclusive.

  5. Empirical Prediction of Aircraft Landing Gear Noise

    NASA Technical Reports Server (NTRS)

    Golub, Robert A. (Technical Monitor); Guo, Yue-Ping

    2005-01-01

    This report documents a semi-empirical/semi-analytical method for landing gear noise prediction. The method is based on scaling laws of the theory of aerodynamic noise generation and correlation of these scaling laws with current available test data. The former gives the method a sound theoretical foundation and the latter quantitatively determines the relations between the parameters of the landing gear assembly and the far field noise, enabling practical predictions of aircraft landing gear noise, both for parametric trends and for absolute noise levels. The prediction model is validated by wind tunnel test data for an isolated Boeing 737 landing gear and by flight data for the Boeing 777 airplane. In both cases, the predictions agree well with data, both in parametric trends and in absolute noise levels.

  6. Instabilities of geared couplings: Theory and practice

    NASA Technical Reports Server (NTRS)

    Kirk, R. G.; Mondy, R. E.; Murphy, R. C.

    1982-01-01

    The use of couplings for high speed turbocompressors or pumps is essential to transmit power from the driver. Typical couplings are either of the lubricated gear or dry diaphragm type design. Gear couplings have been the standard design for many years and recent advances in power and speed requirements have pushed the standard design criteria to the limit. Recent test stand and field data on continuous lube gear type couplings have forced a closer examination of design tolerances and concepts to avoid operational instabilities. Two types of mechanical instabilities are reviewed in this paper: (1) entrapped fluid, and (2) gear mesh instability resulting in spacer throw-out onset. Test stand results of these types of instabilities and other directly related problems are presented together with criteria for proper coupling design to avoid these conditions. An additional test case discussed shows the importance of proper material selection and processing and what can happen to an otherwise good design.

  7. Tool Gear Version 2.3

    SciTech Connect

    2011-12-05

    Tool Gear Version 2 is an expanded collection of programs and software libraries that form the infrastructure on which software tools may be built. The software tools help application developers understand the performance of the programs or help them find programming errors. Tool Gear includes components for gathering data from target programs, either through direct instrumentations or by parsing the output of third-party tools, transmitting the data to a databse, organizing and storing the data, presenting it through a variety of graphical interfaces. Tool Gear is designed to be an extensible system, so users can manage a variety of data and create new ways to present it. Too Gear is sesigned to work with both sequential and parallel programs on multiple computer platforms

  8. Doing Mathematics with Bicycle Gear Ratios.

    ERIC Educational Resources Information Center

    Stump, Sheryl L.

    2000-01-01

    Describes an activity in which students examine bicycle chain-rings, cogs, and gear ratios as a means of exploring algebraic relationships, data collection, scatter plots, and lines of best fit. (KHR)

  9. Design rules to enhance HUMS sensitivity to spur gear faults

    NASA Astrophysics Data System (ADS)

    Liu, Lin

    This dissertation describes the investigation of spur gear design rules that may enhance the sensitivity of conventional fault metrics to typical gear tooth damage. Spur gears represent a fundamental gear geometry that is commonly used in complex transmission system. This thesis explores the influence of simple spur gear design parameters such as diametral pitch, tooth number and pressure angle on gear tooth fault sensitivity. Using static and dynamic analysis, coupled with vibration based fault metrics (FM0, FM4, DI), this work attempts to determine the influence of RPM level, and gear geometry on vibration signatures. Specifically, three types of gear damage are modeled. These include pitting, crack and wear damage. Using a Cornell's gear tooth deflection method, a quasi-static nonlinear mesh gear model is developed that includes effects associated with gear tooth damage. This quasi-static model is integrated into a rigid body model of spur gear mesh dynamics under an applied load. This model is used to simulate the gear mesh dynamics under various RPM levels and applied torque loads. Additionally, the filtering effect of bearing is investigated based on a bearing model. Simulated vibration signatures of bearing case with and without gear tooth damage are used as input into conventional vibration based fault metrics. Assuming that for each spur gear design the gear tooth critical tensile or contact stress is held constant, this dynamic model enables one to vary gear design parameters to evaluate their effect on the vibration signature with and without damage. In this dissertation, the sensitivity of gear design parameters to gear tooth damage is investigated under quasi-static and dynamic loading conditions. Experimental validation is carried out for spur gear designs with various diametral pitch values and for spur gears with increasing crack damage. In the static analysis, enhanced sensitivity is measured with respect to the transmission error. In the dynamic

  10. Support structure of differential gear unit

    SciTech Connect

    Yasui, Y.; Suganuma, T.

    1989-04-18

    A support structure is described of a differential gear unit assembled in a trans-axle casing having a pair of axially spaced carrier portions and an open end closed by a removable cover member secured thereto, an outer case of the gear unit having a pair of side journals rotatable supported by a pair of tapered roller bearings which are removably coupled within respective cylindrical bores in the carrier portions of the trans-axle casing.

  11. Computerized inspection of gear tooth surfaces

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Yi, Zhang; Kieffer, Jonathan; Handschuh, Robert F.; Coy, John J.

    1989-01-01

    An approach is proposed that uses coordinate measurements of the real surface of spiral bevel gears to determine the actual machine tool setting applied during the gear manufacturing process. The deviations of the real surface from the theoretical one are also determined. Adjustments are then applied by machine tool corrections to minimize these surface deviations. This is accomplished by representing the real surface analytically in the same Gaussian coordinates as the theoretical surface.

  12. Landing gear and cavity noise prediction

    NASA Technical Reports Server (NTRS)

    Bliss, D. B.; Hayden, R. E.

    1976-01-01

    Prediction of airframe noise radiation from the landing gear and wheel wells of commercial aircraft is examined. Measurements of these components on typical aircraft are presented and potential noise sources identified. Semiempirical expressions for the sound generation by these sources are developed from available experimental data and theoretical analyses. These expressions are employed to estimate the noise radiation from the landing gear and wheel wells for a typical aircraft and to rank order the component sources.

  13. A comparative study between axial and radial fluxfocusing magnetic gear topologies and mechanical gearboxes

    NASA Astrophysics Data System (ADS)

    Calvin, Matthew

    A variety of magnetic gear topologies have been investigated in recent years as alternatives to traditional mechanical gearboxes. In general these magnetic gears offer advantages in the non-contact transmission of torque including inherent overload protection, reduced acoustic emissions, and a reduction in the number of contacting components subject to wear. The earliest magnetic gear designs however suffered from low volumetric torque densities, which limited their utility for industrial applications. Research into flux focusing magnetic gearbox topologies has resulted in increased volumetric torque densities by actively engaging all of the magnets in the transmission of torque throughout the process. This research compared the volumetric torque density of axial and radial flux focusing magnetic gearbox designs and prototypes to planetary, cycloidal, and harmonic mechanical gearboxes. The rare earth scaled up radial and axial flux focusing topologies were found to have consistently higher volumetric torque densities than planetary gearboxes of comparable diameter. The cycloidal and harmonic gearboxes had comparable volumetric torque densities, with greater volumetric torque densities for some models and lesser volumetric torque densities for others. The expectation is that further improvements in volumetric torque density are possible for flux focusing magnetic gears with additional refinement and optimization of the designs. The current study does show that flux focusing magnetic gear topologies are a plausible future alternative to mechanical gearboxes in applications where their unique torque transmission mechanism would be advantageous.

  14. Evaluation method of lead measurement accuracy of gears using a wedge artefact

    NASA Astrophysics Data System (ADS)

    Komori, Masaharu; Takeoka, Fumi; Kubo, Aizoh; Okamoto, Kazuhiko; Osawa, Sonko; Sato, Osamu; Takatsuji, Toshiyuki

    2009-02-01

    The reduction of the vibration and noise of gears is an important issue in mechanical devices such as vehicles and wind turbines. The characteristics of the vibration and noise of gears are markedly affected by deviations of the tooth flank form of micrometre order; therefore, a strict quality control of the tooth flank form is required. The accuracy of the lead measurement for a gear-measuring instrument is usually evaluated using a master gear or a lead master. However, it is difficult to manufacture masters with high accuracy because the helix is a complicated geometrical form. In this paper, we propose a method of evaluating a gear-measuring instrument using a wedge artefact, which includes a highly precise plane surface. The concept of the wedge artefact is described and a mathematical model of the measuring condition of the wedge artefact is constructed. Theoretical measurement results for the wedge artefact are calculated. The wedge artefact is designed and produced on the basis of the theoretical measurement results. A measurement experiment using the wedge artefact is carried out and its effectiveness is verified.

  15. Study on vibration suppression based on particle damping in centrifugal field of gear transmission

    NASA Astrophysics Data System (ADS)

    Xiao, Wangqiang; Li, Jiani; Wang, Sheng; Fang, Xiaomeng

    2016-03-01

    Though particle damping technology has been applied to vibration suppression in steady state, there are few reports about the study of particle dampers in centrifugal fields because of its nonlinear damping performance and complex mechanism. Introducing particle damping technology into gear transmission will effectively reduce the vibration from gear engaging, especially for harsh working conditions, such as high temperature and oil lubrication. In this paper, we have explored the mechanism of gear excitation and determined the relationship between the rotational speed and gear's modal parameters in centrifugal fields. A mechanical model of the particle damper based on the discrete element method (DEM) in centrifugal fields has been established. Furthermore, the DEM model has been verified by comparing simulation data with experimental data. Based on the model, we have discussed the particle damper's energy dissipation mechanism in centrifugal fields, as well as the calculation method of energy dissipation. Moreover, the influence of the particle size on energy dissipation characteristics has been analyzed. The results can provide theoretical guidance for vibration and noise reduction of the gear transmission.

  16. Gear Tooth Root Stresses of a Very Heavily Loaded Gear Pair-Case Study: Orbiter Body Flap Actuator Pinion and Ring Gear

    NASA Technical Reports Server (NTRS)

    Krantz, Timothy L.; Handschuh, Robert F.

    2015-01-01

    The space shuttle orbiter's body flap actuator gearing was assessed as a case study of the stresses for very heavily loaded external-internal gear pairs (meshing pinion and ring gear). For many applications, using the high point of single tooth contact (HPSTC) to locate the position of the tooth force is adequate for assessing the maximum tooth root stress condition. But for aerospace gearing such an approach may be inadequate for assessing the stress condition while also simultaneously minimizing mass. In this work specialized contact analyses and finite element methods were used to study gear tooth stresses of body flap actuator gears. The analytical solutions considered the elastic deformations as an inherent part of the solutions. The ratio for the maximum tooth stresses using the HPSTC approach solutions relative to the contact analysis and finite element solutions were 1.40 for the ring gear and 1.28 for the pinion gear.

  17. Lightly loaded lubricated impacts: Idle gear rattle

    NASA Astrophysics Data System (ADS)

    Tangasawi, O.; Theodossiades, S.; Rahnejat, H.

    2007-12-01

    Idle gear rattle is associated with the characteristic noise that unselected impacting gears radiate to the environment. It is induced by engine order vibration in the presence of backlash in the unengaged gear pairs, resulting in oscillatory response within their backlash range. A tribo-dynamic model of a front wheel drive manual transmission has been developed to study idle rattle, considering the hydrodynamic contact film reaction and flank friction. The model includes the torsional motions of the idle gears and the lateral motions of the supporting output shafts. The hydrodynamic lubricant film formed between the gear teeth under light impact loads behaves as a nonlinear spring-damper mechanism, whilst the inclusion of the shafts' bearing compliances introduces additional nonlinear terms, which are modelled as piecewise linear functions. The aim of the paper is to extend the existing methodology reported by the authors on idle rattle investigations of geared lubricated systems, based on torsional vibrations only, by considering the system response, which is eventually transferred to the gearbox case through the bearings. These are preliminary results found, which conform closely to experimental measurements taken from a vehicle equipped with a manual transmission of the same type.

  18. An Overview of Landing Gear Dynamics

    NASA Technical Reports Server (NTRS)

    Pritchard, Jocelyn I.

    1999-01-01

    One of the problems facing the aircraft community is landing gear dynamics, especially shimmy and brake-induced vibration. Although neither shimmy nor brake-induced vibrations are usually catastrophic, they can lead to accidents due to excessive wear and shortened life of gear parts and contribute to pilot and passenger discomfort. Recently, NASA has initiated an effort to increase the safety of air travel by reducing the number of accidents by a factor of five in ten years. This safety initiative has spurred an increased interest in improving landing gear design to minimize shimmy and brake-induced vibration that are still largely misunderstood phenomena. In order to increase the understanding of these problems, a literature survey was performed. The major focus of the paper is to summarize work documented from the last ten years to highlight the latest efforts in solving these vibration problems. Older publications are included to understand the longevity of the problem and the findings from earlier researchers. The literature survey revealed a variety of analyses, testing, modeling, and simulation of aircraft landing gear. Experimental validation and characterization of shimmy and brake-induced vibration of aircraft landing gear are also reported. This paper presents an overview of the problem documented in the references together with a history of landing gear dynamic problems and solutions. Based on the assessment of this survey, recommendations of the most critically needed enhancements to the state of the art are given.

  19. X-38 Landing Gear Skid Test Report

    NASA Technical Reports Server (NTRS)

    Gafka, George K.; Daugherty, Robert H.

    2000-01-01

    NASA incorporates skid-equipped landing gear on its series of X-38 flight test vehicles. The X-38 test program is the proving ground for the Crew Return Vehicle (CRV) a gliding parafoil-equipped vehicle designed to land at relatively low speeds. The skid-equipped landing gear is designed to attenuate the vertical landing energy of the vehicle at touchdown using crushable materials within the struts themselves. The vehicle then slides out as the vehicle horizontal energy is dissipated through the skids. A series of tests was conducted at Edwards Airforce Base (EAFB) in an attempt to quantify the drag force produced while "dragging" various X-38 landing gear skids across lakebed regions of varying surface properties. These data were then used to calculate coefficients of friction for each condition. Coefficient of friction information is critical for landing analyses as well as for landing gear load and interface load analysis. The skid specimens included full- and sub-scale V201 (space test vehicle) nose and main gear designs, a V131/V 132 (atmospheric flight test vehicles) main gear skid (actual flight hardware), and a newly modified, full-scale V201 nose -ear skid with substantially increased edge curvature as compared to its original design. Results of the testing are discussed along with comments on the relative importance of various parameters that influence skid stability and other dynamic behavior.

  20. Bearing and gear steels for aerospace applications

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin V.

    1990-01-01

    Research in metallurgy and processing for bearing and gear steels has resulted in improvements in rolling-element bearing and gear life for aerospace application by a factor of approximately 200 over that obtained in the early 1940's. The selection and specification of a bearing or gear steel is dependent on the integration of multiple metallurgical and physical variables. For most aerospace bearings, through-hardened VIM-VAR AISI M-50 steel is the material of preference. For gears, the preferential material is case-carburized VAR AISI 9310. However, the VAR processing for this material is being replaced by VIM-VAR processing. Since case-carburized VIM-VAR M-50NiL incorporates the desirable qualities of both the AISI M-50 and AISI 9310 materials, optimal life and reliability can be achieved in both bearings and gears with a single steel. Hence, this material offers the promise of a common steel for both bearings and gears for future aerospace applications.

  1. Application of face-gear drives in helicopter transmissions

    NASA Astrophysics Data System (ADS)

    Litvin, F. L.; Wang, J.-C.; Bossler, R. B., Jr.; Chen, Y.-J. D.; Heath, G.; Lewicki, D. G.

    1992-05-01

    The use of face gears in helicopter transmissions was explored. A light-weight, split torque transmission design utilizing face gears was described. Face-gear design and geometry were investigated. Topics included tooth generation, limiting inner and outer radii, tooth contact analysis, contact ratio, gear eccentricity, and structural stiffness. Design charts were developed to determine minimum and maximum face-gear inner and outer radii. Analytical study of transmission error showed face-gear drives were relatively insensitive to gear misalignment, but tooth contact was affected by misalignment. A method of localizing bearing contact to compensate for misalignment was explored. The proper choice of shaft support stiffness enabled good load sharing in the split torque transmission design. Face-gear experimental studies were also included and the feasibility of face gears in high-speed, high-load applications such as helicopter transmissions was demonstrated.

  2. Gear-driven draw works have high reliability

    SciTech Connect

    Heinrichs, P. )

    1995-02-20

    Gear-driven draw works have several advantages over conventional chain-driven draw works. Gear-driven draw works have a longer life and working availability (reliability) than chain-driven units, and these factors lead to lower operating costs because of fewer rig shut downs for repairs. The gear shift allows higher speeds and a better adaptation to the performance curve for greater operational efficiency. Additionally, more variable speed selection is possible with direct shifting from 1st to 4th speed. On failure of a gear shift, operation can be continued, with reduced performance, with the autodriller which is integrated directly into the gear shift. Additionally, the gear-driven unit makes less noise and vibration and has a compact construction for reduced weight. The oldest gear-driven draw works have been in use without any gear failure for 27 years, and other gear-driven draw works have worked for many years with no failure.

  3. Application of Face-Gear Drives in Helicopter Transmissions

    NASA Technical Reports Server (NTRS)

    Litvin, F. L.; Wang, J.-C.; Bossler, R. B., Jr.; Chen, Y.-J. D.; Heath, G.; Lewicki, D. G.

    1992-01-01

    The use of face gears in helicopter transmissions was explored. A light-weight, split torque transmission design utilizing face gears was described. Face-gear design and geometry were investigated. Topics included tooth generation, limiting inner and outer radii, tooth contact analysis, contact ratio, gear eccentricity, and structural stiffness. Design charts were developed to determine minimum and maximum face-gear inner and outer radii. Analytical study of transmission error showed face-gear drives were relatively insensitive to gear misalignment, but tooth contact was affected by misalignment. A method of localizing bearing contact to compensate for misalignment was explored. The proper choice of shaft support stiffness enabled good load sharing in the split torque transmission design. Face-gear experimental studies were also included and the feasibility of face gears in high-speed, high-load applications such as helicopter transmissions was demonstrated.

  4. Analysis of the Dynamic Characteristics of Elliptical Gears

    NASA Astrophysics Data System (ADS)

    Liu, Xing; Nagamura, Kazuteru; Ikejo, Kiyotaka

    To date, elliptical gear has been commonly used in automobile, automatic machinery, pumps, flow meters and printing presses for its particular non-uniform rotation. However, the dynamic characteristics of elliptical gears have not been clarified yet. In this study, The calculation as well as the experiment of two elliptical gears, which are a single elliptical gear and a double elliptical gear, is carried out to analyze the dynamic characteristics of elliptical gears. General factors including the torque, the rotation speed and the tooth root stress of the test gears are investigated. According to the analysis conducted in this study, the dynamic input torque variation of elliptical gear becomes larger along with the increase of operating gear rotation speed and the experimental one increases much faster than the calculated one over the Critical Rotation Speed of Tooth Separation (CRSTS) of elliptical gear. The experimental input rotation speed varies according to the variation of input torque, leading to the difference between the experimental output rotation speed and the desired one. The calculation results of the CRSTS of elliptical gears are almost equal to the experimental ones. The dynamic load variation ratios of elliptical gear at different angular position as well as their changing trends with operating gear rotation speed are quite different from each other. And the experimental dynamic load variation ratios of elliptical gear show difference from the calculated ones because of tooth separation and tooth impact. The agreement of the calculation and experimental results proves the validity of this study.

  5. Production Laser Welding Of Gears

    NASA Astrophysics Data System (ADS)

    Guastaferri, David

    1986-08-01

    With the greater acceptance of laser technology as a viable alternative to traditional metals joining methods, the need has arisen to integrate lasers into efficient high production systems. This paper will describe one such system which is dedicated to the automated processing and laser welding of automotive transmission gear components. The system features two (2) 6 KW CO2 lasers, robotic part manipulation, vapor degreasers, air cylinder press stations, fully enclosed weld stations incorporating bottom delivery methods, and programmable computer control which allows complete monitoring throughout the entire production cycle. It is the intent of this paper to describe all segments of the system in detail as to design, manufacture, and integration. Concerning this specific application, an overview from initial inquiry through final installation of the manufactured system will be presented and will focus on the laser welding process and parameter development as it relates to the total systems concept and production goals. The paper concludes with a summary of system field performance to date.

  6. Experimental investigation of fatigue behavior of spur gear in altered tooth-sum gearing

    NASA Astrophysics Data System (ADS)

    Sachidananda, H. K.; Gonsalvis, Joseph; Prakash, H. R.

    2012-09-01

    This paper deals with the contact stress, power loss, and pitting of spur gear tooth in altered tooth-sum gearing for a tooth-sum of 100 teeth when altered by ±4% tooth-sum. Analytical and experimental methods were performed to investigate and compare the altered tooth-sum gearing against the standard tooth-sum gearing. The experiments were performed using a power recirculating type test rig. The tooth loads for the experimental investigations were determined considering the surface durability of gears. A clear picture of the surface damage was obtained using a scanning electron microphotograph. The negative alteration in the tooth-sum performed better than the positive alteration in a tooth-sum operating between specified center distances.

  7. Gear and Transmission Research at NASA Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.

    1997-01-01

    This paper is a review of some of the research work of the NASA Lewis Research Center Mechanical Components Branch. It includes a brief review of the NASA Lewis Research Center and the Mechanical Components Branch. The research topics discussed are crack propagation of gear teeth, gear noise of spiral bevel and other gears, design optimization methods, methods we have investigated for transmission diagnostics, the analytical and experimental study of gear thermal conditions, the analytical and experimental study of split torque systems, the evaluation of several new advanced gear steels and transmission lubricants and the evaluation of various aircraft transmissions. The area of research needs for gearing and transmissions is also discussed.

  8. Computer aided design and analysis of gear tooth geometry

    NASA Technical Reports Server (NTRS)

    Chang, S. H.; Huston, R. L.

    1987-01-01

    A simulation method for gear hobbing and shaping of straight and spiral bevel gears is presented. The method is based upon an enveloping theory for gear tooth profile generation. The procedure is applicable in the computer aided design of standard and nonstandard tooth forms. An inverse procedure for finding a conjugate gear tooth profile is presented for arbitrary cutter geometry. The kinematic relations for the tooth surfaces of straight and spiral bevel gears are proposed. The tooth surface equations for these gears are formulated in a manner suitable for their automated numerical development and solution.

  9. Extending gear life in a coal pulverizer gearbox

    SciTech Connect

    Hansen, T.

    2007-08-15

    A coal-fired power plant in the Western United States experienced short gearbox life in the 13 coal pulverizers operating at the plant. Wear on the bronze bull gear faces was suspected to have been caused by high particulate loading of coal dust and dirt in the gear oil, catalytic reaction between gear oil additives and some of the particulates generated, and high levels of copper in the gear oil. By addressing particulate ingress, adding filtration and switching to a synthetic gear oil, significant benefits were made to the power plant and gear oil life was extended. 2 photos., 1 tab.

  10. Acoustic Measurements of a Large Civil Transport Main Landing Gear Model

    NASA Technical Reports Server (NTRS)

    Ravetta, Patricio A.; Khorrami, Mehdi R.; Burdisso, Ricardo A.; Wisda, David M.

    2016-01-01

    Microphone phased array acoustic measurements of a 26 percent-scale, Boeing 777-200 main landing gear model with and without noise reduction fairings installed were obtained in the anechoic configuration of the Virginia Tech Stability Tunnel. Data were acquired at Mach numbers of 0.12, 0.15, and 0.17 with the latter speed used as the nominal test condition. The fully and partially dressed gear with the truck angle set at 13 degrees toe-up landing configuration were the two most extensively tested configurations, serving as the baselines for comparison purposes. Acoustic measurements were also acquired for the same two baseline configurations with the truck angle set at 0 degrees. In addition, a previously tested noise reducing, toboggan-shaped fairing was re-evaluated extensively to address some of the lingering questions regarding the extent of acoustic benefit achievable with this device. The integrated spectra generated from the acoustic source maps reconfirm, in general terms, the previously reported noise reduction performance of the toboggan fairing as installed on an isolated gear. With the recent improvements to the Virginia Tech tunnel acoustic quality and microphone array capabilities, the present measurements provide an additional, higher quality database to the acoustic information available for this gear model.

  11. Planetary gear train for automotive transmission or the like

    SciTech Connect

    Hiraiwa, K.

    1987-01-27

    This patent describes a planetary gear train transmission comprising: an input shaft operatively connected with a source of rotational energy; first and second plAnetary gear sets respectively including first and second sun gears, first and second ring gears, first and second pinions carriers and first and second sets of pinion gears operatively mounted on the first and second pinion carriers and respectively arranged to mesh with their respective sun and ring gears; a first clutch selectively providing a drive connection between the input shaft and the first sun gear; a second clutch selectively providing a drive connection between the input shaft and the first sun gear; a third clutch selectively providing a drive connection between first and second sun gears; a fourth clutch selectively providing a drive connection between the first sun gear and the second pinion carrier; a first brake selectively rendering the second sun gear stationary with respect to a housing in which the transmission is disposed; a second brake selectively rendering the second pinion carrier stationary with respect to the housing; and an output shaft in drive connection with the first pinion carrier and the second ring gear, such that the transmission produces four forward speeds using only two planetary gear sets.

  12. Starter with planetary gear type speed reducing mechanism

    SciTech Connect

    Imamura, T.; Yukawa, Y.

    1987-01-13

    A starter is described for an internal combustion engine having a ring gear, the starter comprising: a starter motor having an armature shaft; a drive shaft extending in coaxial relation to the armature shaft, the drive shaft having a projection extending radially outwardly from an axial end of the drive shaft adjacent the armature shaft; a pinion in spline engagement with an outer periphery of the drive shaft and adapted to be in mesh with the ring gear of the internal combustion engine; a planetary gear type speed reducing mechanism comprising a sun gear formed on an outer periphery of an axial end portion of the armature shaft of the starter motor, Planetary gears rotatably mounted on the projection of the drive shaft so as to be in meshing engagement with the sun gear, and an internal gear disposed radially outwardly of the planetary gears so as to be in meshing engagement with the planetary gears. The planetary gear type speed reducing mechanism is operative to reduce the rotational speed of the armature shaft and transmit the rotation of the armature shaft to the drive shaft through the sun gear, the planetary gears and the internal gear; a center bracket comprising a cylindrical portion supported through a bearing by an outer periphery of one of the drive shaft and the armature shaft, and a disc-shaped portion extending radially outwardly from an axial end of the cylindrical portion; and a shock absorber unit.

  13. Time-synchronous-averaging of gear-meshing-vibration transducer responses for elimination of harmonic contributions from the mating gear and the gear pair

    NASA Astrophysics Data System (ADS)

    Mark, William D.

    2015-10-01

    The transmission-error frequency spectrum of meshing gear pairs, operating at constant speed and constant loading, is decomposed into harmonics arising from the fundamental period of the gear pair, rotational harmonics of the individual gears of the pair, and tooth-meshing harmonics. In the case of hunting-tooth gear pairs, no rotational harmonics from the individual gears, other than the tooth-meshing harmonics, are shown to occur at the same frequencies. Time-synchronous averages utilizing a number of contiguous revolutions of the gear of interest equal to an integer multiple of the number of teeth on the mating gear is shown to eliminate non-tooth-meshing transmission-error rotational-harmonic contributions from the mating gear, and those from the gear pair, in the case of hunting-tooth gear pairs, and to minimize these contributions in the case of non-hunting-tooth gear pairs. An example computation is shown to illustrate the effectiveness of the suggested time-synchronous-averaging procedure.

  14. Gear synchronizer assembly for power transmission

    SciTech Connect

    Ikemoto, K.; Terakura, Y.

    1986-12-02

    This patent describes a gear synchronizer assembly comprising a gear member rotatable on a transmission shaft, a spline piece formed at one side thereof with a conical portion and thereon with external splines and mounted on a hub portion of the gear member for rotation therewith, and a synchronizer ring mounted on the conical portion of the spline piece for frictional engagement therewith. A hub member is fixedly mounted on the shaft for rotation therewith and has a cylindrical hub portion encircling the synchronizer ring and is formed thereon with external splines. A clutch sleeve encircles the cylindrical hub portion of the hub member and has internal splines in continual engagement with the external splines of the hub member. The clutch sleeve is axially shiftable toward and away from the gear member to be engaged at the internal splines thereof with the external splines of the spline piece. A thrust means is included for moving the synchronizer ring toward the spline piece in shifting operation of the clutch sleeve toward the gear member to effect the frictional engagement of the synchronizer ring with the spline piece. The improvement described here wherein the clutch sleeve is formed at its inner periphery with an internal radial projection axially movable in a corresponding axial groove formed in the cylindrical hub portion of the hub member, and wherein the thrust means comprises a radially contractible annular resilient member arranged in surrounding relationship with the synchronizer ring.

  15. A Computational Investigation of Gear Windage

    NASA Technical Reports Server (NTRS)

    Hill, Matthew J.; Kunz, Robert F.

    2012-01-01

    A CFD method has been developed for application to gear windage aerodynamics. The goals of this research are to develop and validate numerical and modeling approaches for these systems, to develop physical understanding of the aerodynamics of gear windage loss, including the physics of loss mitigation strategies, and to propose and evaluate new approaches for minimizing loss. Absolute and relative frame CFD simulation, overset gridding, multiphase flow analysis, and sub-layer resolved turbulence modeling were brought to bear in achieving these goals. Several spur gear geometries were studied for which experimental data are available. Various shrouding configurations and free-spinning (no shroud) cases were studied. Comparisons are made with experimental data from the open literature, and data recently obtained in the NASA Glenn Research Center Gear Windage Test Facility. The results show good agreement with experiment. Interrogation of the validative and exploratory CFD results have led, for the first time, to a detailed understanding of the physical mechanisms of gear windage loss, and have led to newly proposed mitigation strategies whose effectiveness is computationally explored.

  16. Modal analysis of gear housing and mounts

    NASA Technical Reports Server (NTRS)

    Lim, Teik C.; Singh, Rajendra; Zakrajsek, James J.

    1989-01-01

    Dynamic finite element analysis of a real gear housing is presented. The analysis was conducted for the housing without the rotating components (gears, shafts, and bearings). Both rigid and flexible mounting conditions for the gear housing are considered in this analysis. The flexible support simulates the realistic mounting condition on a rotorcraft, and the rigid one is analyzed for comparison purposes. The effect of gear housing stiffeners is also evaluated. The results indicate that the first six natural modes of the flexibly mounted gear housing in the 0 to 200 Hz range correspond to the translational and rotational rigid body vibration modes of the housing. Above this range, the housing plate elastic modes begin to occur. In the case of the rigid mount, only the housing plate elastic modes are observed which are verified by modal analysis experiments. Parametric studies show that the housing plate stiffeners and rigid mounts tend to increase most of the natural frequencies, the lower ones being affected the most.

  17. An Overview of Landing Gear Dynamics

    NASA Technical Reports Server (NTRS)

    Pritchard, Jocelyn I.

    1999-01-01

    One of the problems facing the aircraft community is landing gear dynamics, especially shimmy and brake-induced vibration. Shimmy and brake-induced vibrations can lead to accidents due to excessive wear and shortened life of gear parts and contribute to pilot and passenger discomfort. To increase understanding of these problems, a literature survey was performed. The major focus is on work from the last ten years. Some older publications are included to understand the longevity of the problem and the background from earlier researchers. The literature survey includes analyses, testing, modeling, and simulation of aircraft landing gear; and experimental validation and characterization of shimmy and brake-induced vibration of aircraft landing gear. The paper presents an overview of the problem, background information, and a history of landing gear dynamics problems and solutions. Based on the survey an assessment and recommendations of the most critically needed enhancements to the state of the art will be presented. The status of Langley work contributing to this activity will be given.

  18. Gear Transmission Error Measurement System Made Operational

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.

    2002-01-01

    A system directly measuring the transmission error between the meshing spur or helical gears was installed at the NASA Glenn Research Center and made operational in August 2001. This system employs light beams directed by lenses and prisms through gratings mounted on the two gear shafts. The amount of light that passes through both gratings is directly proportional to the transmission error of the gears. The device is capable of resolution better than 0.1 mm (one thousandth the thickness of a human hair). The measured transmission error can be displayed in a "map" that shows how the transmission error varies with the gear rotation or it can be converted to spectra to show the components at the meshing frequencies. Accurate transmission error data will help researchers better understand the mechanisms that cause gear noise and vibration and will lead to The Design Unit at the University of Newcastle in England specifically designed the new system for NASA. It is the only device in the United States that can measure dynamic transmission error at high rotational speeds. The new system will be used to develop new techniques to reduce dynamic transmission error along with the resulting noise and vibration of aeronautical transmissions.

  19. Contactless Magnetic Gear for Robot Control Application

    NASA Astrophysics Data System (ADS)

    Komiyama, Hiroki; Uchimura, Yutaka

    This paper describes the application of a magnetic gear to a robot by fulfilling the essential requirements for a robot control, which are velocity control, position control, and force control. A magnetic gear is a transmission device that realizes contactless torque transmission by applying a magnetic force. When using a magnetic gear, cogging torque and spring characteristics need to be considered. In this paper, we introduce an approximate model of cogging torque. This model is used for velocity control to attenuate the disturbance due to cogging torque. In the case of position control, the oscillations due to the spring effect of the magnetic attractive force become a problem. To reduce the adverse effect due to these oscillations, resonance ratio control is applied. We also propose to use a magnetic gear for realizing the force sensorless bilateral control of teleoperation. Thanks to the frictionless transmission of a magnetic gear, the force sensorless estimation of a reaction force can be realized using a reaction force observer.

  20. A computational investigation of gear windage

    NASA Astrophysics Data System (ADS)

    Hill, Matthew J.

    A CFD method has been developed for application to gear windage aerodynamics. The goals of this research are to develop and validate numerical and modeling approaches for these systems, to develop physical understanding of the aerodynamics of gear windage loss, including the physics of loss mitigation strategies, and to propose and evaluate new approaches for minimizing loss. Absolute and relative frame CFD simulation, overset gridding, multiphase flow analysis, and sub-layer resolved turbulence modeling were brought to bear in achieving these goals. Several spur gear geometries were studied for which experimental data are available. Various shrouding configurations and free-spinning (no shroud) cases were studied. Comparisons are made with experimental data from the open literature, and data recently obtained in the NASA Glenn Research Center Gear Windage Test Facility. The results show good agreement with experiment. Interrogation of the validative and exploratory CFD results have led, for the first time, to a detailed understanding of the physical mechanisms of gear windage loss, and have led to newly proposed mitigation strategies whose effectiveness is computationally explored.