谐波减速器柔轮的疲劳开裂失效原因分析

Analysis on Fatigue Cracking Failure of Flexible Gear of Harmonic Reducer

通过显微组织分析、硬度测定以及断口形貌的观察,研究了4个国产柔轮零件出现疲劳开裂的失效原因。结果表明:不同疲劳断裂的零件在组织上无异常,晶粒度级别相差1级,晶粒均匀性好,组织与硬度具有较一致的对应性。但是,零件的纯净度较差,含有较多的大尺寸脆性夹杂物Al_(2)O_(3)和长条状的MnS夹杂。因此,零件纯净度差是造成本次柔轮过早疲劳断裂的主要原因。

By analyzing the microstructure,as well as the hardness measurement and fracture morphology observation,the failure reasons for four cracked flexible wheel parts were studied.The results show that there is no abnormality in the structure of the different parts with fatigue fracture.The difference of grain size grade is 1 and the grain uniformity is good,and the structure and hardness have a relatively consistent correspondence.However,the purity of the parts is poor,containing more large size brittle inclusions Al_(2)O_(3) and long strip MnS inclusions.Therefore,the poor purity of the parts is the main reason for the premature fatigue fracture of the flexible gear.