Abstract: This paper conducts research on the shaking of exterior rearview mirrors of fuel trucks under idling conditions. Fault root cause is identified as excessive idle vibration acceleration of the exterior rearview mirror system through hierarchical investigation along the idle vibration transmission path. Multiple groups of comparative tests are designed according to the structural characteristics of rearview mirrors. Item-by-item test analysis confirms that the core fault cause lies in resonance triggered by the close proximity between the natural frequency of the rearview mirror system and the engine idle excitation frequency. Three improvement measures including modifying the mirror arm structure, changing the material, and adjusting the thickness are proposed. Modal analysis combined with physical prototype tests is adopted to evaluate all schemes from four dimensions: improvement effectiveness, implementability, economy and reliability. The optimal scheme determined through comprehensive comparison is adjusting the thickness of the mirror arm plate to 2.2 mm. The analytical thinking and test methods adopted in this study provide practical references for after-sales maintenance personnel to solve similar idle shaking faults of truck rearview mirrors, and also offer technical references for researchers engaged in the development and design of exterior rearview mirror systems.

Key words: rearview mirrors; vibration; vibration acceleration; modal analysis

摘要： 针对燃油卡车怠速工况外后视镜抖动问题开展研究，通过沿怠速振动传递路径分层排 查，确定故障根源为外后视镜系统怠速振动加速度超标，结合后视镜结构特征设计多组对比 试验。经逐项测试分析，明确故障核心诱因是后视镜系统固有频率与发动机怠速激振频率相 近引发共振。文章提出镜杆结构修改、材质修改、材料厚度调整等三项整改措施，采用模态 分析结合实物试验的方式，从整改有效性、实施难度、成本、可靠性四个维度完成方案评估， 综合筛选得出最优方案为将镜杆板材厚度调整至 2.2 mm。研究所用分析思路与试验手段，可 为卡车售后维修人员处理同类后视镜怠速抖动故障提供实操参考，也能为外后视镜系统研发 设计人员提供技术借鉴。

关键词: 后视镜；抖动；振动加速度；模态分析