Multiple-operating-conditions vibration optimization of electric-drive axle using gear modification

The planetary gear system is the main source of electric-drive axle vibration. Gear modification is an effective method for reducing vibration. However, the vibration response is sensitive to the modification parameters, and it is not easy to obtain appropriate modification parameters. Meanwhile, the unavoidable load deformation of the system causes different gear mesh misalignments for each gear pair, which further increases the difficulty of finding the optimal gear modification parameters. In this study, an optimization model is proposed, with gear modification as a variable and vibration response under multiple operating conditions as an objective. Firstly, loaded tooth contact analysis (LTCA) is utilized to calculate the static transmission error under different misalignment and modification parameters of each gear pair, and the vibration response is obtained using the system dynamics model. Secondly, to improve the optimization efficiency, the Kriging model is used to establish the mapping relationship between the optimization objectives and variables, and the Multi-Island Genetic Algorithm is used to determine the optimal modification parameters. Meanwhile, to prevent gear damage and edge contact, tooth contact stresses and root bending stresses under the limiting operating conditions, and the tooth contact imprints are constrained. Finally, ABAQUS and bench tests were conducted to demonstrate the accuracy of the proposed method. The results show that the constraints meet the requirements under the optimal modification parameters, and the maximum reduction in the root mean square of the system acceleration reaches 55.8% at 50 km/h.