减速箱齿轮轴在运行使用过程中发生了断齿失效,通过宏观检验、化学成分分析、力学性能测试和金相检验等手段分析了轮齿断裂的原因。结果表明:由于机加工不当,在齿面与齿槽交接处留下的加工台阶,加大了齿根部的应力集中程度,使齿轮轴的疲劳强度大大降低,在循环应力的作用下,沿齿根处开裂折断,造成早期疲劳失效。

The teeth of gear shaft in reduction box broke during operations. The breaking reason was analyzed by means of macroscopic examination, chemical composition analysis, mechanical property test, metallographic examination and so on. The results showed that the degree of stress concentration increased at the gear bottom and the fatigue strength of gear shaft reduced a lot when it formed steps between the tooth surface and tooth groove because of improper mechanical processing. The teeth was cracked under the affect of alternating stress, thus resulting in the early fatigue failure.