转盘轴承集聚效应分析及其对回转性能的影响

针对航天发射台转盘轴承工作时出现滚动体集聚导致摩擦力矩增大的问题，研究转盘轴承中滚动体之间间隙变化对集聚效应的影响。通过对典型工位处进行有限元分析，对比不同接触类型转盘轴承的滚道变形和滚动体接触作用力的分布规律。在确定滚动体与隔离块的几何关系后，进一步分析了滚道变形和滚动体接触作用力的时变性对滚动体间隙变化的影响，并将间隙变化和集聚效应建立了联系。有限元计算得到的发射台框架变形与实验测量数据一致，验证了有限元计算的可靠性。仿真结果显示，由于下滚道发生轴向变形，滚动体在运动过程中不断交替进行“爬坡”和“下坡”；滚道径向变形导致滚动体之间增大了较多的间隙；各滚动体的驱动摩擦力不断变化，运动状态具有时变性，当转盘轴承中间隙增加时，运动状态不断变化的滚动体导致增加的间隙出现累积，引起滚动体集聚。为消除滚动体集聚效应，探索其对摩擦力矩的影响，进行了对比实验。结果表明:集聚效应导致发射台的摩擦力矩增加，且变化剧烈。 

Analysis of accumulation effect of turntable bearing and its influence on rotary performance

In order to solve the problem of friction moment increase caused by rolling body accumulation during the rotating process of the space launch pad turntable bearing, this paper studied the influence of the change of clearance between the rolling bodies on the rolling. Based on the finite element analysis of the typical station of the transmitting station, the distribution law of raceway deformation and contact force of the rolling body in different contact types about the turntable bearing are compared, the influence of the time variation of raceway deformation and contact force of the rolling body on the clearance change of the rolling body is further analyzed after the determination of the geometrical relationship of rolling body and isolation block, and the relationship of clearance change and accumulation effect is established. The calculated deformation data of launch pad framework by finite element is consistent with the measured data by experiment, which verifies the reliability of the finite element calculation. The simulation results demonstrate that rolling body experiences alternative movement process of "climbing" and "going downhill" due to the axial deformation of the lower raceway. The radial deformation of raceway results in large clearance between the rolling bodies. The driving friction force of each rolling body changes constantly, and the motion state is time-varying. When there is an increasing clearance, the rolling body with constantly changing motion station will lead to the accumulation of the increased clearance, and as a result, the rolling bodies cluster. To eliminate the rolling body accumulation effect and study its influence on friction torque, the comparative experiment is conducted and the results indicate that the accumulation effect leads to the increase of the friction torque of launch pad and the change is remarkable.