Abstract: The wheel bolt is an important safety part of the whole vehicle. If it breaks during driving, it may lead to serious traffic accidents. In this paper, the problem of wheel bolt thread failure occurred on site is investigated, analyzed and finally solved. The influence factors of bolt design, bolt tightening torque and so on were investigated and analyzed by FTA. Finally, it is confirmed that the thread failure of bolt is caused by too small friction coefficient of thread caused by oil contamination of nut.

Key words: Bolt thread failure; Friction coefficient of the thread

摘要： 车轮螺栓是整车的重要安全部件，若在行驶中出现断裂等问题，则可能出现车轮飞出的严重交通事故。文章针对现场发生的车轮螺栓滑牙问题，进行了问题调查、分析并最终解决问题。问题调查以 FTA 系统分析为指导，对影响螺栓滑牙的各种可能因素进行分析，包括对螺栓设计强度、制造质量、拧紧力矩等均做了系统调查分析。最终确认螺栓滑牙是螺母被油液污染后引起螺纹摩擦系数过小造成。

关键词: 螺栓滑牙；螺纹摩擦系数