送风机电机轴承外圈断裂失效分析

Fracture Failure Analysis of Bearing Outer Race in Motors of Blower

采用化学分析、金相检验、扫描电镜等方法对断裂的送风机电机外圈进行了分析,同时对润滑脂进行了加热条件下的质量损失分析。结果表明,由于轴承外圈硬度偏低,在滚动过程中易磨损;润滑脂的固化降解,加重了金属摩擦副之间的直接对磨。内、外圈滚道间聚集的磨粒使滚柱在滚动过程中发生跳动,不断撞击外圈挡边圆角导致外圈因疲劳而发生断裂。

The failure bearing outer-ring in motors of blower was analyzed by chemical composition analysis, optical microscope and scanning electron microscope, and the lubricating grease was also analyzed by thermogravimetry-differential thermal analysis（TG-DTA）. The results show that the outer-ring wear off easily during the bearing rolling because of the lower hardness;and the direct contact friction between the metal friction pair is created seriously by the grease degradation. The roller jumping and impinging against the bearing outerrace rib continually are caused by the wear particles on the race surface of the bearing during the rollerrolling,which leads outer-ring to fatigue fractures.