某发动机前端轮系张紧器异响分析及改进

Analysis of abnormal noise of an engine belt tensioner and its improvement

针对某发动机前端轮系张紧器在特定转速下的异响问题,通过仿真与试验,分析异响产生原因并进行结构优化。对张紧器进行模态仿真分析,发现张紧器螺旋弹簧的一阶轴向伸缩变形模态频率为347 Hz,与理论计算的异响转速相关频率(344 Hz)非常接近。拆解发生异响的张紧器,发现张紧器第二圈弹簧与壳体底部卡槽凸台发生干涉,产生摩擦噪声。设计优化方案并进行可靠性试验验证,试验结果表明:卡槽凸台高度降低1 mm,可有效降低异响噪声。

Aiming at the abnormal noise problem at certain speeds of front-end belt tensioner, the causes of the abnormal noise are analyzed through simulation and test, and the structure is optimized. The modal analysis of the tensioner show that the first-order axial expansion deformation modal frequency of the tensioner coil spring is 347 Hz, which is very close to the theoretical calculation of abnormal noise frequency(344 Hz). After disassembling the fault tensioner, it is found that the second coil spring of the tensioner interferes with the groove boss at the bottom of the shell, which produces friction noise. The optimization scheme is designed and verified by reliability test. The test results show that the abnormal noise can be effectively reduced if the height of the groove boss is reduced by 1 mm.