Motion stability analysis of cage of rolling bearing under the variable-speed condition

The fluctuation of the cage rotating speed will lead to the strong instability of the cage movement of the rolling bearing, which will seriously affect the operation performance and service life of the bearing. In this paper, a nonlinear dynamic model of a cylindrical roller bearing is established considering the dynamic contact relationship between the rollers, the raceways, and the cage. The variation of cage motion characteristics and its internal mechanism under the uniform, acceleration, deceleration, and harmonic speed fluctuation are discussed, respectively. The effects of angular acceleration, angular deceleration, amplitude, and period of fluctuation on cage stability are analyzed. The results show the unstable motion of the cage mainly happens at the initial stage of the acceleration process and the later stage of the deceleration process. Appropriate increases in angular acceleration and deceleration can help to improve the stability of the cage movement, but excessive speed fluctuations should be avoided to adversely affect the stability of the cage. The guiding force between the cage and the outer raceway plays an important role in the stability of the cage under variable-speed conditions. The results of this paper can provide a theoretical basis for the design and failure analysis of the cage.