Abstract: Aiming at the problem that the acquisition process of automobile components durability test condition was complex, a method to analyze the components durability test condition through the actual driving condition was proposed. Based on the actual operation data of a pure electric bus in Xi’an, the driving condition was constructed. According to the actual parameters of the vehicle, the vehicle simulation model was established, and the stress load condition of the motor output shaft based on the actual driving condition was simulated and calculated. The damage calculation method of motor output shaft under different load was obtained according to the liner fatigue cumulative damage theory and the material S-N curve of motor output shaft. The four-peak-valley rain-flow counting method was used to calculate the damage of motor output shaft under different stress load conditions, and the corresponding cycle life was obtained. The motor speed condition and torque condition corresponding to driving cycle with the shortest life were selected as the motor output shaft durability test condition.

Key words: vehicle engineering, driving condition, components, fatigue life, rain-flow counting method, durability test condition

摘要： 针对汽车零部件耐久性测试工况获取过程复杂的问题，提出了通过实际行驶工况解析出零部件耐久性测试工况的方法。基于西安市某线路纯电动公交车实际运行数据构建得出行驶工况，根据车辆实际参数建立整车仿真模型，仿真并计算得到基于实际行驶工况的电机输出轴应力载荷工况。由线性疲劳累计损伤理论和电机输出轴材料S-N曲线得出电机输出轴损伤值计算方法，并通过四峰谷值雨流计数法统计出不同应力载荷工况下的电机输出轴受到的损伤值，从而得出对应的循环寿命，选择寿命最短的行驶工况对应的电机转速工况和转矩工况作为电机输出轴耐久性测试工况。

关键词: 车辆工程, 行驶工况, 零部件, 疲劳寿命, 雨流计数法, 耐久性测试工况