Study on the transient dynamics of an electric driving system considering the interference fit and thermal expansion effects of tapered roller bearings

The dynamic characteristics of the electric driving system in pure electric vehicles are explored in this paper, with consideration given to the effects of bearing interference fit and thermal expansion. Various factors such as radial stiffness of the bearings, axial stiffness of the bearings, gear mesh stiffness, and backlash were taken into account. A transient dynamic model suitable for transient conditions of electric driving system was established. The model's accuracy has been verified through bench tests. The effects of bearing interference fit and thermal expansion on the dynamic characteristics of the electric driving system under tip in/out conditions were studied. Research shows that under tip in/out conditions, as the interference amount and temperature of the tapered roller bearing increase, the fluctuation amplitude of the motor rotor speed has a downward trend. The amplitude of vibration acceleration fluctuations in the bearing seats of each shaft has been reduced.