Vibration analysis of a six-degree-of-freedom rotor supported on two different deep groove ball bearings with waviness on races

The maximum speed of the motor of the vehicle's electric drive system is gradually increasing. At high speed, the influence of vibration and noise of the bearing rotor system on the electric drive system cannot be ignored. The existing research literature mainly focuses on the vibration characteristics of bearings or only considers the vibration of rotors supported by the same bearing type. However, many rotors are supported on two different bearings in practical applications. In this paper, a dynamic model of a bearing rotor system considering six degrees of freedom is established, taking into account the complexity of the different types of support bearings on both sides. In addition, waviness on the surface of the inner and outer races of the bearing is considered in the model. The accuracy of the model is verified by comparing it with the results of the model in the published literature. The research results show that when the types of bearings on both sides are different, the vibration characteristics of the system are more complex than that of the same type of bearings, with more harmonic components of the vibration and additional sideband frequencies appearing.