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Design Optimization of Differential Bevel Gear for NVH Improvement

American Axle & Manufacturing-Zhenghong Shi, Jui Chen, Mohsen Kolivand, Zhaohui Sun, Gregory Kopp, Ying Peng
Published 2019-06-05 by SAE International in United States
With fast pacing development of automobile industry and growing needs for better driving experience, NVH performance has become an important aspect of analysis in new driveline product development especially in hybrid and electric powered vehicles. Differential bevel gear has significant role in the final drive. Unlike parallel axis gears such as spur or helical gear, bevel gear mesh shows more complicated characteristics and its mesh parameters are mostly time-varying which calls for more extensive design and analysis. The purpose of this paper is to conduct design study on a differential bevel gear unit under light torque condition and evaluate its NVH characteristics. Unloaded tooth contact analysis (UTCA) of those designs are conducted and compared for several design cases with different micro geometry to investigate their pattern position and size variation effects on NVH response. Loaded tooth contact analysis (LTCA) that is based on semi-analytical and semi-FE method is used to compare other mesh parameters such as mesh point, line-of-action (LOA) and mesh stiffness. For experimental study, several 11x16 gear pairs are tested at multiple gear…
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Gear System Parameters and Its Influence on Gearbox Noise

General Motors Technical Centre India-Yogesh Kumar Dewangan, Pranoy Sureshbabu Nair, Dipin Nair
Published 2019-06-05 by SAE International in United States
Tonal noise due to gears is one of the fundamental noise problems in a gearbox. Gear tooth deflections generate dynamic forces that lead to unwanted load fluctuations, thus noise. Different factors that are considered to control this noise, some to mention like proper gear macro design, microgeometry corrections, and housing compliance. However, identifying the appropriate variable as a measure of contribution to the overall response helps in getting more accurate remedial solutions. Some outputs to track are different harmonic components of TE, temperature effects, components of forces, rim compliance and friction.For evaluation, usually, the amplitudes of individual harmonics of transmission error are related to the respective orders of the noise levels assuming it as one of the primary excitation parameters of gear noise. In this paper, a brief overview of TE and its harmonic distribution is discussed with the example of an ideal gear mesh model and then quantifying TE with the introduction of mesh misalignment. The effect of providing additional microgeometry corrections to compensate for the misalignment is also discussed.The study in this paper…
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The Utilization of Onboard Sensor Measurements for Estimating Driveline Damping

Michigan Technological University-Jon Furlich, Jason Blough, Darrell Robinette
Published 2019-06-05 by SAE International in United States
The proliferation of small silicon micro-chips has led to a large assortment of low-cost transducers for data acquisition. Production vehicles on average exploit more than 60 on board sensors, and that number is projected to increase beyond 200 per vehicle by 2020. Such a large increase in sensors is leading the fourth industrial revolution of connectivity and autonomy. One major downfall to installing many sensors is compromises in their accuracy and processing power due to cost limitations for high volume production. The same common errors in data acquisition such as sampling, quantization, and multiplexing on the CAN bus must be accounted for when utilizing an entire array of vehicle sensors. A huge advantage of onboard sensors is the ability to calculate vehicle parameters during a daily drive cycle to update ECU calibration factors in real time. One such parameter is driveline damping, which changes with gear state and drive mode. A damping value is desired for every gear state. Recent years have seen an increasing number of forward gear ratios, from 8-10 in production vehicles.…
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Optimization of Hypoid Gear Tooth Profile Modifications on Vehicle Axle System Dynamics

Chongqing University of Technology-Weiqing Zhang, Shouli Sun
University of Texas- Arlington-Chia-Ching Lin, Yawen Wang, Kan Wang, Teik C. Lim
Published 2019-06-05 by SAE International in United States
The vehicle axle gear whine noise and vibration are key issues for the automotive industry to design a quiet, reliable driveline system. The main source of excitation for this vibration energy comes from hypoid gear transmission error (TE). The vibration transmits through the flexible axle components, then radiates off from the surface of the housing structure. Thus, the design of hypoid gear pair with minimization of TE is one way to control the dynamic behavior of the vehicle axle system. In this paper, an approach to obtain minimum TE and improved dynamic response with optimal tooth profile modification parameters is discussed. A neural network algorithm, named Back Propagation (BP) algorithm, with improved Particle Swarm Optimization (PSO) is used to predict the TE if some tooth profile modification parameters are given to train the model. With the optimal hypoid gear tooth profile modification, a system level analysis of vehicle axle system is performed to verify the improvement on dynamic response aiming at minimizing the TE. A case study of a hypoid gear pair with specified design…
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Target Setting Process for Hybrid Electric Drives Using TPA, Jury Study, and Torque Management

FCA US LLC-Vinod Singh, Anil Charan
InDepth Engineering Solutions-Aniket Parbat
Published 2019-06-05 by SAE International in United States
The idea of improved efficiency without compromising the “fun to drive” aspect has renewed the auto industry’s interest toward electrification and hybridization. Electric drives gain from having multiple gear ratios which can use advantageous operating set points thus increasing range. Furthermore, they benefit significantly from frequent decelerations and stopping as is experienced in city driving conditions. To recuperate as much energy as possible, deceleration is done at high torque. This presents an interesting but serious sound quality issue in the form of highly tonal whine harmonics of rapidly changing gears that do not track with vehicle speed thus being objectionable to the vehicle occupants. This paper presents an NVH target setting process for a hybrid electric transmission being integrated into two existing vehicles, one belonging to the premium segment and another aimed at enthusiasts with off-road applications. The demand for power has shifted from mechanical domain into electrical domain, and as such, the solution to electric drive NVH issues also lay partly, in the way these drive systems are calibrated. A time-domain Transfer Path Analysis…
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Experimental Investigation on Gear Rattle Noise Reduction in Passenger Car

Maruti Suzuki India Limited-Devendra Kumar Khare, Abhishek Lakhanlal Vaishya, Archan Sunibhai Pujara, Radhe Krishna, Kingshuk Satpathy, Ved Prakash Choudhary, Anant Pandey
Published 2019-06-05 by SAE International in United States
Gear rattle noise reduction inside the passenger cabin is one of the major challenges for customer comfort enhancement. Therefore, it becomes a prime target during transmission design and development. Gear rattle is generated due to meshing teeth collision of free gears, which is caused due to torsional vibration of engine transferred through clutch. Vibrations are generated due to free gears teeth impact and are transferred to shaft, bearings and transmission housing. The sound absorption and structural vibration of transmission housing was optimized by changing the geometrical features of the transmission housing that affects radiated noise.Experimental approach for gear rattle noise reduction through transmission housing modification is described in this paper. Moreover, CAE method is also incorporated with the experiments for optimization of future vehicle transmission system designs.
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Improvement of Hypoid Gears Dynamics Performance Based on Tooth Contact Optimization

Chongqing University of Technology-Weiqing Zhang, Xiaodong Guo, Yong Zheng
University of Texas- Arlington-Yawen Wang, Chia-Ching Lin, Teik Lim, Kan Wang
Published 2019-06-05 by SAE International in United States
The meshing noise of hypoid gear has a significant influence on driving axle system. It should be strictly controlled in order to reduce the whole vehicle noise. Meshing internal excitation of hypoid gear is a main source of vibration noise, closely connected with geometrical shape and meshing status. There is no comprehensive analysis on the impact of various contact patterns on vibration noise in previous studies. Therefore, the method for controlling contact characteristics of hypoid gears is studied in this paper, which includes adjusting the position and length of contact pattern, direction of contact trace and the theoretical transmission error. Also, a non-linear dynamic model with multi-freedom for the hypoid gear pair of the driving axle is established to evaluate the dynamic response of the gear pair. Then an example was carried out to improve the dynamic characteristic of hypoid gears by tooth profile modification. It is proved that the dynamic transmission error and mesh force can be reduced effectively through reasonably controlling the contact characteristic parameters of the gear pair. This complete process of…
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Cross-Training Made Possible by Common Control Platform

  • Magazine Article
  • TBMG-34579
Published 2019-06-01 by Tech Briefs Media Group in United States

EMAG L.L.C. is the U.S. subsidiary of a major German machine tool builder that specializes in machine tools for the production of automotive, off-highway, agricultural, and oil field components. The company’s equipment ranges from basic round part turning centers to large-workpiece, five-axis machining centers; gear hobbing machines; and alternative equipment such as laser welding and electrochemical machining centers. This wide variety of machine tools requires an assortment of control technologies to power and manage the motion. For one customer requirement where a major agricultural equipment builder needed grinding, turning, and turn-grind machines, EMAG looked to Siemens for a standardized CNC solution.

 
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Gear Bearings

  • Magazine Article
  • TBMG-34578
Published 2019-06-01 by Tech Briefs Media Group in United States

NASA Goddard Space Flight Center developed gear bearing technology that combines gear and bearing functions into a single unit that significantly improves gear drives for electrical, internal combustion, and turbine motors. The gear bearing design incorporates rifle-true anti-backlash, improved thrust bearing performance, and phase-tuning techniques for superior low-speed reduction. Because it combines gear and bearing functions, it reduces weight, number of parts, size, and cost, while also increasing load capacity and performance.

 

Landing Gear Shock Absorption Testing of Civil Aircraft

A-5B Gears, Struts and Couplings Committee
  • Aerospace Standard
  • ARP5644
  • Current
Published 2019-04-17 by SAE International in United States
The intent of this document is to provide recommended practices for conducting shock absorption testing of civil aircraft landing gear equipped with oleo-pneumatic shock absorbers. The primary focus is for Part 25 aircraft, but differences for Part 23, 27, and 29 aircraft are provided where appropriate.
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