考虑冲击力的球轴承外圈剥落缺陷双冲击现象动力学建模

轴承故障动力学建模是探究剥落激发的双冲击现象与剥落区大小间内在联系的理论基础。基于Hertz接触理论,以外圈滚道表面存在剥落的球轴承为研究对象;对滚动体与剥落区接触的全过程进行内在分析,获得由剥落产生的时变位移激励函数,给出了包含剥落区长度与滚动体直径间比值的冲击力求解公式,并将之引入动力学模型中,建立了考虑冲击力的球轴承外圈剥落双冲击现象动力学模型。运用Runge-Kutta数值积分法求解动力学方程,通过仿真信号与混合陶瓷球轴承外圈故障实测信号对比。结果表明,所建立的考虑冲击力的动力学模型能够有效地预测球轴承故障信号双冲击时间间隔和轴承故障特征频率。

Dynamic modeling of the dual-impulse behavior produced by a spall on the outer race of a ball bearing considering impact forces

The dynamic modeling for a bearing is a theoretical foundation for investigating the interrelation of the dual-impulse behavior induced by a spall on the inner or outer race with the size of the spalling area.A certain bearing with a spall on its outer race was chosen to be the studied object and the overall passing process of the rolling elements across the outer race spall area was deeply analyzed.On this basis,the time-varying deflection excitation function produced by the outer race spall was obtained,and then the formula including the ratio of ball diameter to spall length for calculating the impact force of the rolling elements striking the spall edge was developed.As a result,a novel dynamic model of the ball bearing with a localized spall on its outer race was proposed based on the Hertzian contact theory,which considers the time-varying displacement mechanism and the impact force excitation due to the outer race spall.The solution to the dynamic equations was carried out using the Runge-Kutta numerical integration method.The comparison of the simulated results and the experimental results of the hybrid ceramic ball bearing with an outer race spall shows good effectiveness of the proposed dynamic model which incorporates impact forces in predicting the dual-impulse time interval and the characteristic defect frequency.