某车辆动力总成异常振动分析与改进

摘要

In the light of the abnormal vibration of the power assembly of diesel engine in a sports utility vehicle, resulting in acute vibration of control handle, dynamic characteristics of the power assembly were studied, taking vibration test and finite element simulation analysis together. The resonance of power assembly system was stimulated under the excitation of 2nd order component of the diesel engine's rotating speed in vehicle road test and chassis dynamometer test. A kind of finite element model for vibration analysis of the power assembly of diesel engine was set up to calculate its natural frequencies and modal shapes. It is found that the low stiffness of flywheel shell will cause the low bending stiffness of the power assembly. On the basis of validating the rationality of finite element results of simulation model, the inherent frequency of power assembly was improved by modifying the flywheel shell's structure to move the frequency away from the resonance range and the abnormal vibration of control handle was finally removed. The study gives reference guidance to similar engineering applications.%针对某SUV车柴油机动力总成产生异常振动导致操纵手柄剧烈振动这一实际问题,将振动试验测试与有限元仿真分析结合起来研究动力总成的振动动态特性.通过整车道路试验及转鼓试验,发现柴油机工作转速的二阶激励激起了动力总成系统共振,通过采用有限元方法建立了一种柴油机动力总成振动分析模型,计算分析了此动力总成的振动固有频率和固有振型,找到了导致动力总成弯曲刚度变差的原因——飞轮壳结构刚度不足.在验证了有限元仿真模型计算合理性基础上,通过改进设计飞轮壳结构,提高了动力总成的固有频率,使其避开了共振频率区间,最终消除了操纵手柄的异常振动.该试验与仿真分析方法对解决同类工程问题具有参考指导和应用价值.