Research On Oil Replenishment Mechanism Of Rolling Bearing

As the lubricant layer on the bearing raceway surface is continuously overrolled by the rolling elements during operation, its thickness gradually decreases and the rolling bearing consequently falls into a starved condition. However, in engineering it can be found that a bearing working in starvation without oil replenishment can still keep in good working conditions for a long time, which implies there must be some kind of spontaneous oil replenishment mechanisms in the bearing to maintain the normal operation of the bearing. This paper systematically studied the oil replenishment mechanism of raceway in bearing, including oil replenishment mechanism near the contact region and oil replenishment mechanism away from contact region on bearing raceway free surface. The main work and conclusions are as follows:A model of oil distribution near the contact region is established, which considers the effect of disjoining pressure and capillary forces. The results show that, at low speed and static conditions, the capillary force and disjoining pressure may improve the inlet oil supply condition and further improve the lubrication performance,which implies that the effect of disjoining pressure and capillary forces may be one of oil replenishment mechanisms in bearing under low speed and static condition.The oil distribution model for revolving raceway surface is established, which considers the effect of surface tension, centrifugal force, initial oil layer thickness and oil viscosity on thin oil layer flow. And the change of oil layer thickness is investigated based on the numerical simulation.The oil distribution model for ball on disk configuration is also established, which considers the effect of the surface tension, gravity, centrifugal force and disjoining pressure on the oil flow on the raceway free surface outside the contact area. Based on the numerical simulation, the influencing laws of each force were investigated under different conditions on the oil layer thickness variations and changes of the oil thickness at central raceway.Based on the developed starvation lubrication model, the process of oil layer repeatedly entering and leaving the contact region is investigated with consideration of the change of oil layer distribution outside the contact area. The change of oil layer thickness is explored under different initial oil layer thickness.. Furthermore, the oil recovery process due to surface tension was observed using the ball on disk film thickness measurement, which provides a qualitative validation for numerical simulation.