Modeling of the vibrations caused by ball bearing defects

Abstract

In this study a shaft-ball bearing system is modeled in order to investigate the vibrations of ball bearings with running surfaces defects. Shaft and bearing was modeled as mass-spring system and balls were assumed have masses in order to investigate the effects of the balls on the overall vibrations. It is well known that the behaviour of the system has a nonlinear character under dynamic conditions. Equations of motion were obtained and solved with a computer program developed in order to study the radial and axial vibrations. The results obtained from simulation program for shaft and balls were analyzed both time and frequency domains. The ball masses are shown not to have a significant effect on the overall vibration behaviour of the shaft bearing system. The vibrations of shaft and the ball bearing system have been observed to have sensivity for different working conditions. The effects of localized defects on bearing running surfaces (i.e. surfaces of inner and outer rings and balls) on the shaft-ball bearing vibrations were investigated by using the simulation program. When the results obtained from the computer simulation have been compared with previous studies available in the literature, a reasonably good agreement has been observed.