Effects of Tooth Modifications on the Mesh and Dynamic Characteristics of Differential Gearbox Used in Electric Vehicle

In order to reduce the vibration and noise for the differential gearbox used in electric vehicle, a coupled gear–shaft–bearing–housing dynamic model was developed considering the elastic support by shaft, bearing and housing. Three tooth modification schemes were proposed to investigate the effects of modification type on the mesh behaviors. Results show that the tooth modification scheme with a combined drum–tooth end modification for lead direction and linear addendum modification for profile direction can make the contact load distribution better. The contact pattern was located in the middle of the tooth, and the maximum contact pressure was decreased by 19% to 937 MPa. And the peak–peak value of transmission error was decreased by 33% for high-speed stage and 26% for intermediate stage. The tooth modifications tend to decrease the acceleration responses obviously, especially for the high-frequency range. The structure noise was reduced about 3.5–4.5 dB in x, y and z directions for the selected bearing locations. The analysis results can be applied to guide the design of electric vehicle differential gearbox with low noise level.