地铁车辆轴箱接地端子开裂改进措施研究

Improvement Measures for Metro Vehicle Axle Box Grounding Terminal Fracture

在列车通过部分区间道床时,其轮轨激扰作用导致轴箱线缆支架发生共振,进而导致轴箱接地端子异常开裂问题。对此,建立有限元模型进行仿真,并通过锤击试验,确认了原始支架的固有模态特征。通过振动传递路径分析,明确了轨道→轴箱→线夹板→支架→端子为主要传递路径,轨道→轴箱→端子为次要传递路径,并据此提出支架改进方案及端子优化方案。高频激振试验台测试结果表明,短悬臂类方案效果优于变截面类方案,改变端子结构也可降低应力水平。线路测试验证结果表明,8 mm厚的短悬臂改进方案能大幅降低支架和端子的应力水平,改善效果明显。

When train is passing track bed of some intervals,its wheel-rail excitation can cause coupled resonance of axle box cable bracket,resulting in abnormal fracture of the axle box grounding terminals.Targeting this problem,finite element model is established for simulation,and the inherent modal characteristic of the original bracket is identified through hammer test.According to vibration transmission path analysis,the primary transmission path is identified to be rail→axle box→wire splint→bracket→grounding terminal,and rail→axle box→grounding terminal is the secondary path.Optimization schemes of bracket and terminal are proposed accordingly.The test results from high frequency excitation vibration test bench indicate that the scheme with short cantilever is better than that with variable cross-section,and modifying the terminal structure can also decrease stress level.The line verification test results show that the optimization scheme with 8 mm thick short cantilever can drastically decrease the stress level of bracket and terminal,demonstrating evident improvement.