轴承滚子缺陷激励下高铁轴箱系统振动特性研究

Vibration characteristics of high-speed train axle-box system excited by bearing roller defects

以某型高速列车转向架上轮对和轴箱系统为研究对象,构建一种包含轴箱轴承滚子缺陷的车辆-轨道耦合动力学模型,并利用现场试验数据验证轴箱轴承−车辆−轨道耦合动力学模型的有效性。通过仿真计算获得在京津线轨道随机不平顺激扰工况下轴箱的振动加速度时间历程以及轴承滚子与外圈的接触载荷时间历程,结合轴承滚子缺陷数学分析模型,研究轴承滚子缺陷激扰工况下轴箱系统内部结构的接触振动特性。研究结果表明:当轴承滚子出现缺陷时,轴箱横向和垂向振动加速度包络谱在滚子故障频率和2倍滚子故障频率的倍频处出现振动加速度峰值,且以保持架旋转频率10.32 Hz进行振幅调制;缺陷滚子与外圈接触载荷频谱主要分布在0~100 Hz的低频段,在200~1000 Hz频段内出现以轴承保持架旋转频率为频率间隔的一系列峰值;随着轴承滚子缺陷宽度的增加,滚子与外圈接触载荷中高频段所占成分逐渐增加,表明轴承滚子缺陷宽度的增加会逐渐引起轴承滚子与外圈的中高频激振,加强轴箱轴承内部构件之间的动态作用从而加速轴承的疲劳破损失效;列车运行速度在250 km/h左右时,仿真数据表明轴承滚子缺陷宽度需限制在1 mm以内,尽量减少因轴承滚子缺陷宽度过大而引起的滚子与外圈接触载荷升高造成结构疲劳等一系列问题。

Taking the wheel set and axle box system on the bogie of a high-speed railway train as the research object,a vehicle track coupling dynamic model including the defect of bearing roller was built.The effectiveness of the axle box bearing-vehicle-track coupling dynamic model was verified by using the field test data.The vibration acceleration time history of the axle box and the roller-outer raceway contact load time history under the excitation of the random track irregularity on the Beijing-Tianjin line were obtained through simulation.Combined with the bearing roller defect mathematical analysis model,the contact vibration characteristics of the internal structure of the axle box system under the excitation of the bearing roller defect were studied.The research results show that when the bearing roller is defective,the lateral and vertical vibration acceleration envelope spectrum of the axle box has a peak vibration acceleration at the multiple frequency of the roller fault frequency and twice the roller fault frequency.The amplitude is modulated with the cage rotation frequency of 10.32 Hz.The frequency spectrum of the defective roller-outer raceway contact load is mainly distributed in the low frequency band of 0~100 Hz,and a series of peaks occur in the frequency band of 200~1000 Hz with the rotation frequency of the bearing cage as the frequency interval.With the increase of the bearing roller defect width,the composition of the high frequency segment of the roller-outer raceway contact load gradually increases,indicating that the bearing roller defect width will gradually cause the medium and high frequency excitation of the bearing roller and the outer raceway,strengthen the dynamic action between the axle box bearing internals,and thus accelerate the fatigue failure of the bearing.When the train speed is about 250 km/h,the simulation data shows that the width of bearing roller defect should be limited within 1 mm,so as to minimize a series of problems such as structural fatigue caused by the increase of the roller-outer raceway contact load caused by the excessive defect width of bearing roller.