Collaborative Deformation Analysis of Motor-Bearing System Considering Multiphysical Coupling Environment for In-Wheel Electric Vehicle Applications

The in-wheel motor-bearing (IWMB) system is a critical component of the in-wheel motor (IWM) driving electric vehicle. Studying the deformation issues of the IWMB system under service conditions is of significant importance for enhancing of the reliability and durability of IWM drive systems and vehicles. Current research on the system's deformation problems faces issues such as incomplete consideration of multifield loads, unclear coupling relationships between loads, and the separation of the IWM and bearing as independent components in studies. This may lead to substantial discrepancies between the analysis results and actual conditions. Aiming at the above problems, this article focuses on a permanent magnet IWMB system. Based on an analysis of the coupling relationships among various physical field loads involved, a comprehensive dynamic analysis model of the IWMB system is established, considering the coupling effects of electromagnetic, thermal, mechanical, and flow fields, as well as actual structural assembly constraints. The validity of the developed model is verified through experiments. The model is then used to investigate the collaborative deformation mechanisms and laws of the IWMB system under the combined cyclic action of various mechanical loads (including electromagnetic force, torque, centrifugal force, and radial force) and thermal loads. The main factors of deformation and the main influence of temperature on deformation are analyzed. This study can provide a theoretical basis for improving the reliability of the IWMB system.