简谐转速波动工况下滚动轴承保持架动态特性分析

Analysis on Cage Dynamic Characteristic of Roller Bearing Under the Condition of Simple Harmonic Rotational Speed Fluctuation

转速波动会恶化滚动轴承内部接触状态,对保持架的动态特性产生重要影响。针对滚动轴承转速周期性波动的特点,将其简化为简谐波动,以圆柱滚子轴承NU306为研究对象,建立了轴承塑性材料柔性接触的非线性动态有限元仿真模型,采用显式LS-DYNA对其在不同转速波动频率和不同转速波动幅度工况下的运行过程进行了动态仿真,获得了圆柱滚子轴承在简谐转速波动下的保持架角速度曲线以及滚子与保持架接触力曲线,分析了不同转速波动频率和波动幅度对保持架动态特性的影响。研究结果表明,保持架角速度曲线的波动周期主要由内圈转速的波动周期决定,且转速波动频率愈大,进出承载区滚子与保持架之间的碰撞次数越多;转速波动幅度愈大,保持架角速度曲线的最大转速值越大,最小转速值越小,平均转速值变化不大,从而保持架角速度曲线的波动范围会明显增大。仿真结果与实验结果吻合良好,验证了所建立有限元模型的正确性。

The rotational speed fluctuation will worsen the internal contact state of roller bearings,which has important influence on the dynamic characteristics of cage.Considering the characteristic of periodic fluctua.tion of rotational speed of roller bearings,it is simplified as a simple harmonic wave.Taking cylindrical roller bearing NU306 as investigation object,a nonlinear dynamic finite element model for plastic material flexible contact of a bearing is established.Based on explicit LS-DYNA,the dynamic simulations for nonlinear opera.tion process under different fluctuation frequency and different fluctuation amplitude condition of rotational speed are carried out,and the angular speed curve of cage and the contact force curve between roller and cage are obtained.The influences of fluctuation frequency and fluctuation amplitude on the dynamic characteristics of cage are analyzed.The study results show that the fluctuation period of the angular speed curve of cage is mainly determined by the fluctuation period of the rotational speed of inner ring,and the greater fluctuation frequency of rotational speed,the more the number of collisions between rollers in and out of load zone and cage.The greater fluctuation amplitude of rotational speed,the greater maximum speed of angular speed curve of cage,and the smaller minimum speed of angular speed curve of cage,but the change of average speed is very small,so the fluctuation range of angular speed curve of cage will increase obviously.The simulation results are in good agree.ment with the experimental results,and the correctness of the finite element model is verified.