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.

研究表明，小幅度的相对滑动可能导致滚子与滚道之间的接触面出现微动磨损或疲劳。通常，球-平面接触中的微动模式包括切向、径向、扭转和旋转模式。在本研究中，提出了轴向微动模式的新概念和相应的力学模型，用于粗轧机中四列圆锥滚子轴承（FTRB）的研究。建立了引起轴向微动现象的轴向推力和径向载荷的力学模型，并结合预位移原理和弹性接触理论计算了耦合载荷分布。此外，还建造了一个工程试验台，用于采集由轴向微动现象引起的振动信号。将改进的多元变分模态分解（IMVMD）与多元复合多尺度加权置换熵（MCMWPE）相结合来处理振动信号，以提供更好的FTRB维护策略。分析结果表明，轴向微动状态和接触面滑移区域受轴向推力、摩擦系数和滚子位置角的影响。不同交叉角下的轴向推力非线性变化，接触面的径向载荷随滚子的列数和位置角而变化。微动轴承的MCMWPE明显低于健康轴承，并且存在规律的冲击现象。