机车用水泵轴断裂失效分析

针对机车用水泵轴在使用中容易发生断裂的问题，对水泵轴断口的宏观和细观形貌进行了分析，认为断口为典型的弯扭复合疲劳断口．通过检测水泵轴上装配的齿轮，发现由于齿轮的加工误差过大，在轴的退刀槽根部造成了较大的附加拉应力，最终导致轴的断裂．因此及时消除齿轮的加工误差，同时提高安装精度，是防止此类断裂发生的关键．

Fracture fatigue analysis of pump shaft used on locomotive

Aiming at the fracture in operation of damageable pump shaft used on locomotive, macroscopic and microscopic analysis of the pattern of fractured cross section in pump shaft is conducted and it is recognized that the fracture is typically caused by combined action of bending and torsion fatigue. Checking the gear on the pump shaft, it is found that there is excessive processing error with it and a greater additional tensile stress at the root of shaft shoulder is occurred which results eventually in the fracture of shaft. Thus immediate elimination of processing error of the gear as well as improvement installation accuracy will be the key to the prevention of such fracture.