Study of Skidding and Friction Torque for a Deep Groove Ball Bearing in a Permanent Magnet Synchronous Motor

Skidding motion and friction torque of ball bearings will have serious impact on the performance of permanent magnet synchronous motor (PMSM), thus, it is helpful to investigate and suppress them of ball bearings in PMSM. In this paper, the electromechanical coupling dynamic model of a PMSM is proposed. The PMSM rotor is supported by two deep groove ball bearings and is driven by electromagnetic torque. The dynamic model of supporting bearing is proposed to simulate the lateral motion of inner raceway and rotational motions of balls. The unbalanced magnetic pull (UMP) is calculated and applied on the PMSM rotor. Effects of bearing clearance and raceway surface roughness on the friction torque and skidding behavior between balls and raceways are studied. These results may benefit high performance PMSM design.