发动机摇臂及摇臂轴座断裂失效分析

Fracture Failure Analysis on Diesel Engine Rocker Arm and Rocker Arm Seat

某新开发机型发动机在进行性能开发试验时,功率突然下降,拆检发现进气摇臂断裂,同时摇臂轴座断裂。本文通过有限元计算、断口分析、金相及硬度检测等手段进行失效分析,确定失效原因。主要原因为液压挺柱在排气制动过程中,使活塞与排气门碰撞,导致摇臂轴座断裂,另外制造原因也是断裂的主要原因之一。

While the newly developed engine is given with a performance test, its power dropped suddenly. The intake rocker arm and the rocker arm seat were found to carry fractures after the engine was dismantled . This paper analyzes the failure reasons with finite element analysis, fracture analysis, metallographic inspection and hardness test and concludes that the piston collided with exhaust valve when the hydraulic tappet moved in the exhaust and brake process, leading fractures in the rocker arm seat. In addition, mechanical manufacturing is another reason causing this problem.