驱动轴三阶激励下的某纯电动车低频抖动研究

针对某纯电动全油门加速行驶过程地板产生的低频抖动问题,经主观评价及试验诊断分析后,排查出电机转速在3000~4200 r/min,地板出现明显0.33阶次振动。通过传递路径分析阶次激励源产生的原因,并进行路试试验、理论分析、动力总成及传动系统试验模态等分析方法,排查出整车急加速过程中地板低频抖动激励源为驱动轴内三轴销万向节产生的附加弯矩激励源与动力总成Y向平动模态耦合,因而产生共振。结合开发车型设计情况,提出通过降低悬架高度来降低万向节附加弯矩,然后对调整的方案进行试验验证。试验后,地板0.33阶次抖动由0.065 g降为0.025 g,提高了乘坐舒适性。

Research on Low-frequency Jitter of a Pure Electric Vehicle under the Third-order Excitation of Driving Shaft

In view of the low-frequency vibration of the floor during full-throttle acceleration of a pure electric,after subjective evaluation and test diagnosis and analysis,it is found that the motor speed is 3000~4200 r/min,and the floor has obvious 0.33 order vibration.Through the transmission path analysis of the causes of order excitation source,and the road test,theoretical analysis,power assembly and transmission system test modes,it is found that the excitation source of floor low-frequency shaking during the acceleration of the whole vehicle is the additional bending moment generated by the three-axis pin universal joint in the driving shaft coupled with the y-direction translational mode of the power assembly,resulting in resonance.Combined with the design of the developed vehicle,it is proposed to reduce the additional bending moment of the universal joint by reducing the suspension height,and then the adjustment scheme is tested and verified.The third-order jitter is reduced from 0.065 g to 0.025 g,which greatly improves the ride comfort.