电机轴承动力学特性分析及疲劳寿命计算

Dynamic Characteristics Analysis and Fatigue Life Calculation of Motor Bearings

摘要: 深沟球轴承是电机中的关键部件，明确轴承的动力学特性对轴承疲劳寿命预测和改进设计具有重要意义。基于接触力学和流体力学，文章结合深沟球轴承内部各部件之间的几何变形与受力情况，建立了轴承动力学模型，根据滚珠、套圈和保持架之间的协调变形关系，分析了轴承的动力学特性。首先，以深沟球轴承为对象，结合轴承几何结构和内部相互作用关系，建立了轴承动力学模型；然后，以轴承工作中的典型工况作为轴承动力学模型的仿真输入数据；其次，采用四阶龙格–库塔法和牛顿–拉夫逊法对动力学模型进行求解；最后，基于L-P理论，对轴承疲劳寿命进行计算。结果表明，保持架打滑率的稳定速率与转速呈反相关、与载荷呈正相关，低转速高载荷工况下的打滑率能更快地趋于稳定；滚珠与保持架之间的碰撞力在启动阶段震荡明显，且与载荷呈正相关，高载荷低转速工况下的碰撞力能更早地进入稳定状态；轴承寿命与转速和载荷呈反相关关系。

Abstract: Deep groove ball bearings are key components in electric motors, and clarifying their dynamic characteristics is of great significance for bearing fatigue life prediction and design improvement. Based on contact mechanics and fluid mechanics, combined with the geometric deformation and force conditions among the internal components of the deep groove ball bearing, a bearing dynamic model was established. This model analyzes the dynamic characteristics of the bearing according to the coordinated deformation relationship among the balls, rings, and cage. First, taking the deep groove ball bearing as the subject and combining its geometric structure and internal interaction relationships, the bearing dynamic model was established. Then, typical working conditions during bearing operation were used as input data for the bearing dynamic model simulation. Next, the fourth-order Runge-Kutta method and the Newton-Raphson method were used to solve the dynamic model. Finally, the bearing fatigue life was calculated based on the L-P theory. The results show that the stabilization rate of the cage slip rate is inversely related to the rotation speed and positively related to the load, meaning the slip rate stabilizes faster under low-speed, high-load conditions. The collision force between the ball and the cage clearly oscillates during the starting phase and is positively related to the load, with the collision force entering a stable state earlier under high-load, low-speed conditions. The bearing life is inversely related to the rotation speed and the load.