Abstract: Vibration responses and kinematic parameters when a ball rolls over and impacts with a localized surface defect can provide efficient inputs and theoretical foundations for bearing fatigue analysis and fault diagnosis. A dynamic model for rolling ball bearings with localized defects is proposed based on GUPTA model. In this model, every bearing component (i.e., rolling ball, inner raceway and outer raceway) has 6 degrees of freedom. Relative slippage and lubricant traction are also considered. Moreover, defects are modeled completely with consideration of additional clearance due to material absence, changes of Hertzian contact stiffness and changes of contact force directions. The relationships between bearing accelerations and impact forces at balls and defects are analyzed. Furthermore, the effects of the shaft speed and the defect width on bearing vibrations are investigated. The simulation results show that, because the relative slippage and the impact force effect are all considered, the proposed model is capable of simulating the dynamic characteristics of rolling ball bearings with surface defects more reasonable and providing valuable conclusions for fatigue analysis and quantitive diagnosis of rolling ball bearings.

Key words: dynamic model, localized surface defect, quantitive diagnosis, rolling bearing