关键词: 后视镜；抖动；振动加速度；模态分析

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