高速角接触球轴承保持架不稳定运动机理分析

Analysis on the unstable movement mechanism of high-speed angular contact ball bearing cages

建立了球和保持架六自由度的角接触球轴承动力学为基础的磨损仿真模型。以某仪表转子轴承为算例,分析了不同载荷工况和保持架间隙比下保持架的运动,从球与保持架兜孔碰撞点位置、碰撞力的大小和频率等方面探讨了保持架不稳定运动的机理。发现在纯轴向载荷下,因球与兜孔碰撞点位置的不同,保持架会沿轴向摆动;轴向径向联合载荷作用下,因球的轨道速度随接触角变化,球与保持架碰撞力和频率都增加,导致保持架的运动不稳定;轴向和旋转径向负荷下,保持架兜孔间隙与挡边间隙比B/R<1时,保持架质心运动轨迹接近于圆形,保持架的离心力作用于球上增大了球与兜孔的碰摩;间隙比大于1时,保持架质心轨迹为多边形或无规律涡动,引导挡边对保持架的约束减小了球与兜孔的相互作用,保持架兜孔的磨损率较低;圆形的质心轨迹是保持架稳定运动的一种状态,但从保持架磨损和能耗的角度看,对保持架的磨损寿命不利。

A dynamic wear simulation model for angular contact ball bearings with six-degree-of-freedom ball and cage was established.Taking a certain instrument rotor ball bearing as an example,the cage motion under different load conditions and cage clearance ratios was analyzed.The mechanism of the cage unstable motion was discussed from the aspects of the ball-pocket collision,and the magnitude and frequency of the impact force.It is found that under the pure axial load,the cage will swing along the axial direction due to the ball-pocket collision at different positions.Under the joint of axial and radial loads,the orbital velocity of the ball varies with the contact angle,and the collision force and frequency of the ball and cage increase,resulting in the unstable motion of the cage.Under the axial and rotating radial load,when the ratio of the ball-pocket clearance to the cage-guide land clearance B/R is less than 1,the orbit of the cage mass center whirl is close to a circle.The centrifugal force of the cage acts on the ball,resulting in an increase in the ball-pocket collision.When the clearance ratio is greater than 1,the centroid trajectory of the cage is polygonal or irregular,and the constraint of the guide land on the cage reduces the interaction between the ball and cage,so the wear rate of the cage is lower.The circular centroid trajectory is a state of stable motion of the cage,but from the perspective of cage wear and energy loss,it is unfavorable for the wear life of the cage.