Experimental Study on Temperature Rise of New Energy Vehicle Drive Motor Bearings Under Grease and Driving Conditions

The temperature rise of drive motor bearings in new energy vehicles is a critical factor affecting their reliability and lifespan, with grease performance and driving conditions being the primary determinants of this rise. Addressing the lack of research on how different grease types affect the temperature rise of drive motor bearings under operational conditions, this study utilizes a high-temperature, high-speed testing machine for drive motor bearings in new energy vehicles. It conducts a comparative analysis of the temperature rise in bearings lubricated with four different types of grease under three typical driving conditions: emergency start–stop, smooth driving, and high-speed driving. Results show that the temperature rise varied from 25.1 °C to 50.3 °C under rapid speed change, 22.7 °C to 40.2 °C at fixed speed, and that grease No.3 achieved the lowest temperature rise and the highest limiting speed (23,000 rpm). These results provide quantitative evidence for selecting grease and optimizing bearing design.