某传动拨叉开裂失效分析及结构优化

Failure Analysis and Structure Optimization of Crack of A Transmission Fork

采用扫描电镜、金相显微镜等方法对某传动拨叉断口形貌、金相组织及成分进行了检测。通过有限元方法模拟了该零件在使用中的应力,并进行了结构优化。结果表明,断裂是由于零件工作时受间断冲击力引起的,过大的力在其凸台的根部产生裂纹源而发生过载断裂。增加零件凸台根部倒角和凸台宽度可大幅降低在运行过程中的应力值。

The fracture morphology, microstructure and composition of a transmission fork were examined by scanning electron microscope and metallographic microscope. The stress of the part in the use was simulated by the finite element method. And the structure optimization was carried out. The reuslts show that fracture is caused by the intermittent impact force in the part work, too large force produces a source of crack in the root of the boss and the overload fracture occurs. Adding parts boss root fillet and boss width can greatly reduce the stress during operation.