基于电机动态模型的电动汽车高速斜齿轮动载荷计算及寿命预测

Dynamic Load Calculation and Life Prediction of High Speed Helical Gear of Electric Vehicle Based on Motor Dynamic Model

与传统燃油汽车相比,电动汽车传动系统及其零部件通常在高频、强冲击、超长周次的动态载荷作用下运行,更易导致变速器齿轮发生接触疲劳破坏。为了准确计算电动汽车高速斜齿轮实际工况下的动态载荷,预测其使用寿命,以某定传动比变速器电动汽车为研究对象,建立车用永磁同步电机的矢量控制模型,基于瞬时道路工况对模型进行仿真,得到循环工况下驱动电机的动态转矩输出,并对实验结果进行验证;基于赫兹接触理论,以电机的动态转矩作为变速器驱动转矩,计算得到循环工况下高速斜齿轮接触疲劳危险位置的应力谱,并进行循环计数,获取了循环工况下高速斜齿轮接触应力幅值均值-频次关系。根据修正的P-S-N曲线及疲劳累积损伤理论,预测电动汽车变速器高速斜齿轮接触疲劳寿命,为电动汽车变速器齿轮动态疲劳寿命预测提供了理论方法。

Compared with the traditional fuel vehicles,the electric vehicle transmission system and its parts often run under the dynamic load of high frequency,strong impact and long cycle,which can easily induce the contact fatigue damage of transmission gears.In order to accurately calculate the dynamic load of high speed helical gear of electric vehicle and predict its service life,the vector control model of permanent magnet synchronous motor for vehicle is established with a certain transmission ratio transmission electric vehicle as the research object.Based on the simulation of the model under instantaneous road conditions,the dynamic torque output of vehicle motor under cyclic conditions is obtained,and the results are tested and verified.The dynamic torque of the motor is used as the driving torque of the transmission to calculate the contact stress of the gear pair,the contact stress spectrum of the gear pair under the cyclic condition is obtained,and the load cycle statistics are carried out.The mean-frequency relationship of contact stress of high-speed helical gear under cyclic condition is obtained.According to the modified P-S-N curve and fatigue cumulative damage theory,the contact fatigue life of high-speed helical gear of electric vehicle transmission is predicted,which provides a theoretical method for predicting the dynamic fatigue life of electric vehicle transmission gear.