外反馈显示某型轮式装载机驱动桥出现大量大螺旋锥齿轮崩齿故障,但常规的内在质量检测未发现异常,初步判断为作业工况工作应力大于齿轮的抗弯曲疲劳应力所致。对大螺旋锥齿轮采用强力喷丸工艺后,台架试验证实改善效果不明显。进一步分析发现,失效大螺旋锥齿轮齿根位置存在一根异常的黑线,金相分析表明失效大螺旋锥齿轮齿根存在过回火马氏体,且在过回火马氏体位置发现一根未扩展的裂纹,同时,配对小螺旋锥齿轮对应位置存在未回火马氏体,表明大小螺旋锥齿轮在齿根处曾发生干涉并大量发热,致使齿轮回火甚至淬火。调整大小螺旋齿轮接触斑点及装配的齿侧间隙后,崩齿故障得以显著降低。 External feedback shows that a large number of large spiral bevel gear collapse faults occurred on a certain type of wheel loader drive axle. However, no abnormalities were found in conventional internal quality inspection. It was initially determined that the working stress in working condition was greater than the flexural fatigue stress in gear. The use of powerful shot peening on a large spiral bevel gear, the bench test confirmed that the improvement effect is not obvious. Further analysis showed that there was an abnormal black line at the root of the failed large spiral bevel gear. Metallographic analysis showed that there existed over tempered martensite at the root of the failed large spiral bevel gear, and a At the same time, there is un-tempered martensite at the corresponding position of matching small spiral bevel gear, which indicates that the size spiral bevel gear has been interfered at the tooth root and generated a large amount of heat, causing the gear to temper or even quench. After adjusting the size of the spiral gear contact spots and assembly of the flank clearance, the collapse of the tooth can be significantly reduced.