Effects of Cage Flexibility and Crack Propagation on Roller-Cage Pocket Interaction Forces and Dynamics in Cylindrical Roller Bearings

The cage in a cylindrical roller bearing (CRB) is utilized to prevent direct contact between the rollers and reduce friction. The interaction of forces between the rollers and the cage pocket can cause the initiation of cage cracks, ultimately leading to cage fracture. In this process of failure evolution, the circumferential stiffness of the cage decreases as the depth of the cage crack increases, impacting the interaction forces between the rollers and cage. The interaction force between the roller and cage pocket is categorized into impact load and internal force distributed in the cage beam and circumferential connection. This study examines the impact of cage flexibility and crack propagation on cage behavior. Cage flexibility is estimated using a lumped mass technique and integrated into the CRB dynamic model. Subsequently, the interaction forces between the roller and cage pocket are analyzed under various cage crack scenarios. The results show that cage flexibility and its crack can cause the difference in load distribution between the left and right circumferential connection of the cage and affect its service performance. It is feasible to detect the cage crack failure by its vibration signal due to the cage crack’s influence on the CRB cage vibration frequency signal.