LAUSR

Long-life high-precision bearings are widely used in space mechanisms. This type of bearing relies on the stable rotation of the porous material cage to ensure lubrication, and cage wear is the main failure mode, so the dynamic characteristics of cage directly determine the life and reliability of the bearing. This article developed a trajectory deviation evaluation method to analyze the cage dynamic behavior of long-life high-precision ball bearings. To calculate the deviation of cage rotation motion trajectory under high speed, a tracking system of cage rotation motion trajectory is applied to capture the cage rotation motion. Then, generalized extreme value distribution (GEVD) is used to fit the nonuniform deviation, R-square is used to evaluate the goodness of fit, and the evaluation criteria of relative cage instability are defined. Under stable conditions, R-square can be as high as above 0.95 for almost all deviation fits. However, the fitting performance decreases as wear deepens. In addition, with the increase in cage rotational speeds, the fitting curve is wider and its extreme value is bigger. Under unstable condition, the fitted curve is skewed to the right and becomes immense, and the extreme value is very big. These facilitate qualitative and quantitative analyses of cage dynamic behavior.