Investigation of motor bearing thermal characteristics for in-wheel electric vehicle applications.

In-wheel motor (IWM) bearings are key components for load and motion transfer and are highly integrated into wheels. The heat issues of IWM bearings are directly related to the reliability and safety of IWMs and vehicles. This paper focuses on examining the bearings of a 15 kW IWM. The corresponding thermal analysis model is established after determining the heat source of IWM electromagnetic loss and bearing mechanical loss. The established model's validity has been confirmed through temperature experiments on the in-wheel motor. Subsequently, according to the influence rules of different heat sources on bearing temperature rise, it is found that the effect of electromagnetic loss on bearing temperature rise is greater than that of friction loss. The influence of friction loss on bearing temperature rise is linear, while the influence of electromagnetic loss on bearing temperature rise is non-linear. With the increase in vehicle speed, the overall bearing temperature will increase, and no matter how the vehicle speed changes, the main factor that causes the temperature increase of bearing components is always the electromagnetic loss of IWM. [ABSTRACT FROM AUTHOR]