球轴承内圈剥落缺陷双冲击特征动力学建模

基于Hertz接触理论,以内圈滚道表面存在局部剥落的球轴承为研究对象,对球轴承局部剥落故障所激起的非线性激励机理进行研究,分析球轴承双冲击现象激励机理。将滚动体与球轴承内外圈非线性接触特性纳入考虑,提出时变位移激励与时变接触力激励相耦合的球轴承局部剥落双冲击现象动力学模型。研究中采用Runge-Kutta数值积分法求解该二阶非线性动力学微分方程,并对故障球轴承仿真信号进行双冲击时间间隔特征验证。在不同转速和内圈剥落尺寸条件下开展仿真与实验研究,通过仿真和实测信号的双冲击时间间隔与理论双冲击时间间隔对比分析,仿真信号的双冲击时间间隔与理论值对比的误差结果皆小于2%,与实测信号的双冲击时间间隔值对比的误差结果皆小于12%;同时,仿真信号与实测信号具有很好的相似性,从而验证了该动力学模型的有效性。 

Dynamic modeling for double-impulse behavior of ball bearing in the presence of a spall on inner race

A ball bearing in the presence of a spall on the inner race was studied. Based on Hertzian elastic contact theory, a research on non-linear excitation mechanism excited by the spall fault was carried out, and the internal excitation mechanism of double-impulse phenomenon was studied. As a result, a novel coupled non-linear dynamic model for double-impulse behavior of the ball bearing with a spall on the inner race was proposed, by considering the contact characteristics between the rolling elements and the bearing races and the excitation mechanism of time-varying displacement and contact force. The coupled solution to the second order non-linear differential equations was obtained by applying the Runge-Kutta numerical integral method, the relationship of double-impulse time spacings extracted from the simulated vibration signal was investigated. By comparison of the simulated, experimental and theoretical double-impulse time spacings under diverse shaft rotating speeds and inner race spall sizes of the ball bearing, all the relative errors between the simulated and theoretical double-impulse time spacings were less than 2 percent, and that between the simulated and the experimental double-impulse time spacings were less than 12 percent. In addition, the simulated signal agreed well with the experimental signal. Consequently, it was concluded that the effectiveness of the proposed nonlinear dynamic model in predicting the double-impulse time separation and vibration characteristics of the ball bearing was well validated.