110 kV断路器弹簧操作机构凸轮组合部件断裂原因分析

Analysis of the Fracture of Cam Assemblies in the Spring Operating Mechanism of a 110 kV Circuit Breaker

110 kV断路器弹簧操作机构在进行低电压分合试验中,储能轴与凸轮组合部件中的轴承套与销轴断裂,在对其进行了宏观形貌观察、热酸浸蚀观察、显微组织检测后结果表明:储能轴与凸轮组合部件中的轴承套内表面存在制造生产时遗留下的磨削裂纹,当进行分合试验时,储能保持掣子与轴承套产生较大相互挤压应力作用,储能轴与凸轮组合部件中的销轴承受弯曲应力断裂,并导致圆柱滚球和轴承套断裂。

During low-voltage opening and closing tests of the spring operating mechanism of a 110 kV circuit breaker,the bearing sleeve and the pin shaft,which are the assemblies of the energy storage shaft and the cam,were broken.Results of macroscopic morphology observation,hot acid etching observation and microstructure inspection show that the inner surface of the bearing sleeve,which is the assembly of the energy storage shaft and cam,has grinding cracks left over from the manufacturing process.During the opening and closing tests,the stored energy retaining pawl and the bearing sleeve produce a large mutual extrusion stress.The pin bearing which is the assembly of the energy storage shaft and cam fractured under bending stress,causing the fracture of the cylindrical ball roller and the bearing sleeve.