中间轴疲劳断裂失效分析

Analysis on Fracture of Intermediate Shaft

采用金相显微镜、扫描电子显微镜、硬度计等检测工具,对分动器中间轴断裂原因进行了分析与研究。结果表明,中间轴的断裂属于早期旋转弯曲疲劳断裂。断裂的主要原因是结构设计不合理,即台阶根部半径太小,且与螺纹根部距离过近,两处的应力集中程度都较大。针对中间轴失效原因采取了一些合理的预防措施,如增大台阶根部圆角半径,取消螺纹,避免了中间轴疲劳断裂。

The cause of fracture of a transfer intermediate shaft was investigated by using metallographic microscope, scanning electron microscope, hardness tester and other instruments. The results show that the fracture of the intermediate shaft belongs to an early rotation bending fatigue fracture, and arises mainly form its unreasonable structure that radius of the step root is too small and too close to the thread root, thus resulting in larger stress concentration in the two places. In order to avoid the stress concentration, some reasonable precautions, such as increase in the radius of the step root, cancellation of the screw, have been adopted, thus avoiding the fatigue fracture of the intermediate shaft.