汽车变速器阶梯轴扭振计算模态分析

Computational Mode Analysis on Torsional Vibration of Stepped Shaft in Vehicle Transmission

以某国产轿车变速器输入轴的扭振模态为研究对象,建立基于分布质量弹性体的连续阶梯轴扭振模型,计算该轴的前4阶扭振固有频率和对应模态振型。同时建立基于有限元法的离散阶梯轴扭振模型,对比了划分9个和13个扭转单元的有限元模型与分布质量弹性体模型在计算该轴前4阶扭振固有模态上的误差,可知划分13个扭转单元的有限元模型计算误差较小,既满足工程实际中不超过5%的误差要求,又保证有较少的自由度,可以代替分布质量弹性体模型对该变速器输入轴扭振模态的计算进行离散及简化。

The torsional vibration mode of transmission input shaft equipped to a domestic car is researched.The continuous torsional vibration model of stepped shaft based on distributed mass elastic body is established and the first four torsional vibration natural frequencies and corresponding mode shape are calculated.The discrete torsional vibration model of the stepped shaft based on finite element method is established too.By comparing the finite element models of 9 and 13 torsional elements with distributed mass elastic body model on the deviation of the first four torsional vibration natural frequencies respectively,it is found that the calculated errors of finite element model with 13 torsional elements are smaller and they can be used to substitute the distributed mass elastic model to discretize and simplify the torsional vibration mode calculation of transmission input shaft since it can meet the error requirement of not exceeding 5 % in engineering practice and has fewer degrees of freedom.