Analysis of axial fretting mode and mechanical model for a four-row tapered roller bearing

Abstract

Studies show that relative sliding of small amplitude may result in fretting wear or fatigue of the contact surface between the roller and the raceway. Generally, fretting mode in a ball-on-flat contact include tangential, radial, torsional and rotational modes. In the present study, the new concept of axial fretting mode and the corresponding mechanical model are proposed for the study of a four-row tapered roller bearing (FTRB) in the roughing mill. The mechanical models of axial thrust and radial load causing axial fretting phenomenon are established and the coupled load distributions are calculated by considering the pre-displacement principle and the elastic contact theory. Moreover, an engineering test rig is built to collect the vibration signals caused by axial fretting phenomenon. The improved multivariate variational mode decomposition (IMVMD) combined with multivariate composite multiscale weighted permutation entropy (MCMWPE) are applied to process the vibration signals in order to provide better maintenance strategy about the FTRBs. The analysis results indicate that the axial fretting regime and slip region of contact surface are affected by axial thrust, friction coefficient, and roller position angle. The axial thrust under different cross angles varies nonlinearly and the radial load of the contact surface varies with the row number and position angle of the roller. The MCMWPE of fretting bearing is significantly lower than that of healthy bearing, and there is a regular impact phenomenon.