某船用柴油机气马达传动轴断裂失效分析

Fracture Failure Analysis of Gas Motor Transmission Shaft in a Marine Diesel Engine

某项目开发过程中,气动马达的传动轴起动约25~30次时发生早期断裂故障。通过对使用工况、结构特点、硬度分析、金相分析等方面,分析了该气马达传动轴断裂失效的原因。分析结果表明:该传动轴的断裂模式为多源性疲劳断裂。主要原因为异常冲击造成的传动轴花键根部产生初始裂纹,伴随着花键轴不合理的结构设计,不合理的热处理工艺等因素,导致裂纹逐步扩展,最终发展为断裂失效。

During the development of a project,the transmission shaft of an air motor is broken when it starts the engine for 25-30 times.The fracture analysis of the gas motor transmission shaft is applied on several aspects,such as use conditions,the structure,hardness,and metallographic analysis.The results of analysis show the transmission shaft failure mode is Multi-Source Fatigue Fracture.The main reason is a crack is appeared on the tooth root of spline shaft because of an abnormal shock.The crack is extending into a breakage,because of the incorrect design structure of spline shaft and the incorrect heat treatment process.