某数控车床主轴轴承发生损伤,采用宏观观察、化学成分分析、扫描电镜和能谱分析、金相检验、硬度测试等方法分析了轴承的损伤原因。结果表明:两个主轴轴承均发生早期接触疲劳,但损伤程度轻微;其中一个轴承滚道表面存在磨粒磨损形成的损伤凹坑和犁沟,磨粒为车床加工产生的硬铝碎屑,碎屑进入该轴承内,在接触表面形成挤压凹坑,并随滚动体运动,在滚道表面形成犁沟,从而使接触区的粗糙度增大,最终导致轴承转动不良并出现异响。

The main shaft bearing of a digital controlled lathe was damaged. The causes of bearing damage were analyzed by macroscopic observation, chemical composition analysis, scanning electron microscopy and energy spectrum analysis, metallographic examination and hardness test. The results show that early contact fatigue occured in both main shaft bearings, but the damage degree was slight. There were damage pits and furrows formed by abrasive wear on the surface of one of the bearing raceways. The abrasive particles were hard aluminum debris produced by lathe machining. The debris entered the bearing, formed extrusion pits on the contact surface and moved with the rolling body. The furrows were formed on the surface of the raceway, which increased the roughness of the contact area and eventually led to poor rotation of the bearing and abnormal noise.