辛延君2， 王超2，姜爱龙1,2，
1.内燃机可靠性国家重点实验室，山东 潍坊 261061； 2. 潍柴动力股份有限公司，山东 潍坊 261061
摘要：为解决某船用发动机耐久试验中凸轮表面出现裂纹和材料剥落的问题，通过宏观形貌观察、金相分析及硬度检测等对凸轮进行失效分析，确认凸轮表面失效模式为接触疲劳失效，主要原因为凸轮在加工过程中磨削量太大，经磨削液冷却造成表面二次淬火，耐久试验中在长期较高的接触应力作用下，引起凸轮表面压碎，表层金属材料剥落。优化凸轮精磨过程中的磨削参数，降低磨削速度和径向进给量，再次耐久试验，凸轮表面完好。通过本文分析，确定凸轮表面剥落产生的原因，对凸轮轴产品质量的提升具有参考价值。
Abstract：In order to solve the cam surface crack problem for a marine diesel, macro analysis such as observation, metallographic analysis and hardness test failure analysis was carried out on. Test results show that the failure modeof cam surface is contact fatigue, which is mainly caused by large grinding amount during the machining process. The surface is cooled by grinding liquid which brings secondary hardening. The cam surface is crushed by the effect of long-term high contact stress during endurance test process. Then the grinding parameters are refined and new cam performs quite well in the test. The analysis of the cam surface crack is of great significance to the promotion of the camshaft product quality, which could improve the service life of the camshaft and the service life of the engine.
Key Words：cam；contact fatigue；secondary quenching；material peeling off
|
