关键词: 主动磁悬浮轴承系统, 保护轴承, 类石墨碳基薄膜, 减摩

Abstract:  The rotor of the AMBs and the auxiliary bearing might produce huge impacts， vibrations and friction heat during the rotor falling which was easy to make the auxiliary bearing fail. The thermal characteristics during the vertical rotor drop on auxiliary bearings were studied， and the main factors leading to the auxiliary bearing failure during the rotor falling were analyzed herein. Subsequently， a method of reducing friction was proposed to deposit solid lubricating film(GLC) on the key surfaces of auxiliary bearings by magnetron sputtering technology， and the rotor drop tests of coated and uncoated auxiliary bearings were performed. The results show that the maximum temperature of the auxiliary bearing is as 210.60 ℃ at a drop speed of 20 000 r/min， which appear in the high-speed rubbing stage between the rotor and the inner ring end face of the bearing. The temperature is higher than the tempering temperature of bearing steel of 160 ℃， which will lead to the failure of the bearing burn. The surface appearance of the channel and end face of the self-lubricating auxiliary bearings coated with GLC film is obviously better than that of the uncoated ordinary auxiliary bearing after the drop tests. The hardness decrease of the inner ring end face caused by friction and heating is lighter， the trajectory of the center of mass and axial displacement are more stable， and the temperature rise is lower. The GLC films play a key role in self-lubrication， wear resistance and friction reduction， the service life and service reliability of the auxiliary bearings are improved. It also provides an idea and method to solve the problems of auxiliary bearing failures easily in AMBs. 

Key words:  , active magnetic bearing system（AMBs）, auxiliary bearing, graphite-like carbon film（GLC）, friction reduction