Dynamic characteristics of angular contact ball bearings with mild defect on outer raceway

A dynamic model of angular contact ball bearings considering mild defect on outer raceway was developed. The mild defect model is comprised of interactions between ball and defect edges and bottom. The blunt wedge contact theory is employed to model the interaction between balls and defect edges. The surface roughness and curvature radius of the defect bottom are both considered based on the Hertzian contact model and mixed lubrication theory for point contact to describe the interaction between balls and the defect bottom. The dynamic model of defective ball bearings is developed in the inertial coordinate system and solved by the fourth-order Runge-Kutta method to perform dynamic analysis of the bearing components. The characteristics of vibration responses and dynamic behaviors of bearing components are analyzed. Experiments are conducted on a test rig in which various arc length faults are introduced onto raceway surfaces. Vibration signals of outer ring are collected to validate the dynamic model of the defective angular contact ball bearing. The modulation phenomenon and mechanism of ball passing frequencies are discussed specifically. The analysis results can provide valuable insights into bearing design and fault diagnosis.