The impact of roller dynamic unbalance of high-speed cylindrical roller bearing on the cage nonlinear dynamic characteristics

On the basis of the rolling bearing dynamics, this paper presents the nonlinear dynamic differential equations of high-speed cylindrical bearing considering the impact of roller dynamic unbalance, which are solved by GSTIFF algorithm. Parametric evaluation of cage stability as a function of roller dynamic unbalance helps identify a critical value of unbalance of which instability is triggered, and then the orbit of cage mass center, Poincaré map and velocity deviation of cage are used to assess the nonlinear dynamic characteristics and stability. The results as following: (1) Roller dynamic unbalance has an important effect on the operating status of cage, which can make the cage motion move from quasi-periodic motion to chaotic motion. (2) Roller dynamic unbalance changes along the angular direction of roller axis have the most serious impact on the stability of cage, followed by the radial direction and the axial direction. (3) There is a critical value of roller dynamic unbalance to trigger the cage instability response. Beyond this threshold, the cage whirl orbit tends to spiral out, which implies progressively increasing cage forces, and therefore, leading to an eventual cage failure.