Abstract: Driveline and housings are connected by roller bearings. The bearing stiffness is nonlinear and coupling in all directions and changes with the input torque of drive axle, which leads to variation in the drive axle system dynamics. Based on the nonlinear bearing theory, the finite element method and modal synthesis method, a drive axle final drive gear transmission system dynamic model with final drive gear transmission assembly, differential gear transmission assembly, hub assembly and housings etc. is built. According to the magnitude of the input torque of the pinion shaft, the load cases are set out into light load, medium load and heavy load. Nonlinear bearing stiffness is calculated corresponding to each load case. The axial stiffness and radial stiffness of final drive roller bearing with load change characteristics are analyzed. Dynamic analysis of the whole drive axle system to a unit harmonic transmission error at the hypoid gear mesh is performed in the case of different input torques. The influence of the input torque on the drive axle is researched. The frequency response characteristics of final drive hypoid gear dynamic meshing force is analyzed when the drive axle system works in different load cases. The results show that the drive axle system dynamics change with the size of the input torque with a certain regularity, and can guide the design of the vibration and noise reduction of drive axle system in order to avoid dangerous conditions effectively.

Key words: drive axle, dynamic analysis, input torque, nonlinear stiffness, roller bearing