一种轴承松动-内圈缺陷耦合的转子系统动力学模型

Dynamic model of rotor system coupled with bearing looseness and inner ring defect

当轴承松动与内圈缺陷同时出现时,将对转子系统动态特性产生较为严重的影响,不利于对转子系统进行故障诊断与状态监测。针对这一问题,提出了一种轴承松动-内圈缺陷耦合的转子系统动力学模型,分析了含内圈缺陷-松动耦合故障轴承的转子系统振动动态特性。首先,根据赫兹理论与轴承运动学理论分析了轴承受力;然后,根据胡克定律与转子系统集中质量法建立了松动-内圈缺陷耦合的转子系统动力学模型;最后,采用数值仿真方式获取了转子系统的振动响应,探讨了转速和载荷对松动-内圈缺陷耦合转子系统振动特性的影响,并通过实验对该模型的准确性进行了验证。研究结果表明:松动-内圈缺陷同时存在的轴承频谱上出现了典型的干摩擦特征频率,即1/2倍旋转频率及其倍频,且其幅值与转速、载荷呈正比;此外,1/2倍旋转频率及其倍频、旋转频率及其倍频与内圈缺陷频率的组合频率的出现,表明了松动和内圈缺陷同时发生,该现象在转子系统另一个轴承上也有所体现。该研究结果为轴承转子系统的耦合故障检测提供了理论依据。

Aiming at the problem that bearing looseness and inner ring defect occurring at the same time,which affected the dynamic characteristics of the rotor system and was not conducive to the fault diagnosis and condition monitoring of the rotor system,the dynamics model of rotor system with coupling of inner ring defect and loose bearing was proposed.The vibration dynamic characteristics of rotor system with inner ring defect-loose coupling fault bearing were analyzed.Firstly,the bearing forces were analyzed based on Hertz theory and bearing kinematics theory.Then,the dynamic model of rotor system with coupling of outer ring defect and loose bearing was established based on Hooke s law and concentrated mass method of the rotor system.Finally,the vibration response of the rotor system was obtained by numerical simulation,the influence of the rotation speed and load on the vibration characteristics of the coupled rotor system of the coupled looseness and inner ring defect were discussed,and the accuracy of the model was verified by experiments.The research results show that the characteristic frequency of dry friction is 1/2 times the rotation frequency and double the frequency,and its amplitude is proportional to the speed and load.In addition,the occurrence of 1/2 times the rotation frequency and its doubling,the combination of the rotation frequency and its doubling frequency with the inner ring defect frequency indicates that loosening and inner ring defect occur at the same time,which is also reflected in the other bearing of the rotor system.The research results provide a theoretical basis for coupling fault detection of bearing rotor system.