Vibration analysis of a cylindrical roller bearing considering multiple localized surface defects on races

Cylindrical roller bearings are important components in rotating machineries. As one of the main failure modes, localized surface defects such as pits and spalls can be caused on the surfaces of the races or rollers of the bearings due to periodic loads. It is useful to investigate the dynamic characteristics of a cylindrical roller bearing with localized surface defects, which can provide some guidance to bearing defect detection and diagnosis. In this paper, a new dynamic model is proposed to investigate the vibrations of a cylindrical roller bearing with multiple localized surface defects on its inner or outer race. The time-varying excitations caused by the multiple localized surface defects and non-Hertzian contact relationship between the logarithmic-profile rollers and races of the bearing are considered in the bearing dynamic modelling. The dynamic model of the bearing is described as a two-degree of freedom lumped spring-mass system, which includes the effects of the damping, time-varying compliance of the bearing, time-varying deflection excitations and time-varying contact stiffness excitations caused by the defects on its inner or outer race, and profile of the rollers. The effects of the width, angular position and number of the defects on the vibrations of the bearing are investigated. The results show that the proposed method provides a new method to simulate the effects of multiple localized surface defects on the vibrations of a cylindrical roller bearing, which can enhance understanding vibration characteristics of the bearing with multiple localized surface defects on its races.