矿用机械电机转轴断裂失效分析与设计优化

Failure Analysis and Design Optimization of Motor Shaft Fracture of Mining Machinery

针对某矿用机械电机转轴断裂的问题,通过对电机转轴的外观分析和实物取样失效分析,得知电机转轴断裂属于扭转疲劳断裂。进一步对电机转轴进行了有限元仿真分析,得出在极限扭矩工况下电机转轴花键过渡圆弧处最大Von Mises应力为769.5 MPa;参考FKM标准对电机转轴进行了强度评估,电机转轴轴颈过渡圆弧处的材料利用率为1.19,超过允许值1,导致轴颈处疲劳强度不能满足要求。据此,提出了4种结构优化方案,通过综合比较最终确定将花键过渡圆弧处倒角改为5 mm,轴颈表面粗糙度控制在Ra3.2的优化方案最优。

Aiming at the problem of shaft fracture of a mining machinery motor, through the appearance analysis of the motor shaft and the failure analysis of the physical sampling, it is concluded that the motor shaft fracture is a torsional fatigue fracture. Furthermore, the finite element simulation analysis of the motor shaft shows that the maximum Von Mises stress is 769.5 MPa under the limit torque condition.The strength of the motor shaft was evaluated with reference to the FKM standard. The material utilization rate at the transition arc of the motor shaft journal is 1.19, which exceeds the allowable value of 1, and causes the fatigue strength at the journal to not meet the requirements. Based on this, proposed and compares four structural optimization schemes. Through comprehensive comparison, it is finally determined that the chamfering angle of the spline transition arc is changed to 5 mm, and the optimization scheme of the journal surface roughness control in Ra3.2 is optimal.