滚动轴承非线性时变参数动力学模型与故障机理研究

基于滚动轴承故障动力学模型研究其振动特性及故障机理是实现轴承故障准确诊断的基础。为描述滚动轴承缺陷对其振动响应特性的影响，考虑滚动体与缺陷的相对几何关系，提出了时变接触变形与时变刚度耦合的滚动轴承故障非线性动力学模型。以NSK6205深沟球轴承为对象，通过建立6+N_b自由度非线性时变参数动力学模型，分析了滚动体通过外圈缺陷区域时接触变形、接触刚度以及振动响应的变化过程，得到了不同缺陷尺寸下滚动轴承故障冲击振动响应特征变化规律。理论分析和实验研究结果表明，随着缺陷尺寸的增加，滚动轴承故障振动响应产生由双冲击到多冲击的变化特征，不同缺陷尺寸下，滚动体进入和离开缺陷过程中产生的冲击响应明显不同。研究成果为基于振动信号实现滚动轴承故障尺寸判断提供了理论依据。

Nonlinear Time-varying Parameter Dynamic Model of Rolling Bearing and Failure Mechanism Research

Research on the vibration mechanism and vibration characteristics of the faulty bearing based on the dynamic model of the rolling bearing fault is the basis for the accurate diagnosis of the bearing fault. In order to describe the impact of rolling bearing defects on its vibration response characteristics, considering the relative geometric relationship between rolling elements and defects, a nonlinear dynamic model of rolling bearing faults coupled with time-varying contact deformation and time-varying stiffness is proposed. Taking NSK6205 deep groove ball bearing as the object, a 6+N_b degree of freedom nonlinear time-varying parameter dynamic model was established to accurately describe the process of contact deformation, contact stiffness and vibration response of rolling body as it passed through the outer ring defect area, and the variation law of fault impact vibration response characteristics of rolling bearing under different defect sizes was obtained. Theoretical analysis and experimental research results show that as the size of the defect increases, the vibration response of rolling bearing faults will change from double shock to multiple shocks. Under different defect sizes, the impact response of the rolling elements during the process of entering and leaving the defect is significantly different. The research results provide a theoretical basis for realizing the fault size judgment of rolling bearing based on vibration response.