Optimization of Hypoid Gear Tooth Profile Modifications on Vehicle Axle System Dynamics

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 parameters and working condition is presented to validate the proposed method. The modal characteristics and dynamic response before and after the tooth profile modification have been compared. The results conclude that minimization of TE, the main excitation of vehicle axle gear whine noise and vibration, with optimal tooth profile modification parameters can improve the overall NVH behavior. The proposed approach provides a better understanding of an optimal design hypoid gear set to minimize TE and effect on vehicle axle system dynamics.