某型号变速箱在台架试验过程中, 双联齿和与之啮合的512齿轮均发生失效事件。采用断口分析、金相检验、硬度测试以及化学成分分析等方法对失效件进行了检验。结果表明: 由于双联齿和512齿轮的齿面存在严重的异常接触, 加之双联齿的有效硬化层深度和心部硬度均低于技术要求, 从而导致在台架试验过程中双联齿表面发生严重的接触疲劳剥落, 与之啮合的512齿轮发生弯曲疲劳断齿。

The duplicate gear and its coupled 512 gear of a gear box both failed during bench test. The methods of fracture analysis, metallographic examination, hardness test and chemical compositions analysis were used to test the failure parts. The result show that the serious abnormal contact surface between the duplicate gear and 512 gear, as well as the off-specification of hardening depth and core hardness of the duplicate gear caused severe contact fatigue spalling on surface of the duplicate gear and bending fatigue fracture of the 512 gear.