Research on the frictional contact behaviors of high-speed motorized spindle bearing with oil-air lubrication

As an important supporting element of rotating mechanisms, the frictional wear of rolling bearing causes low motion accuracy and energy dissipation, which are the chief contributing factors for system failure. To simulate the service statuses of rolling bearing under different lubrication conditions, the wear and frictional behavior between the GCr15 ball-on-disc contact pairs was experimentally analyzed to investigate the effects of rotating speed, loading, supplied oil quantity and air pressure on the friction and wear properties of the point contact pairs. As the experimental results show, the use of oil-air lubrication yields the smallest friction coefficient as compared to those of the grease and the oil lubrication modes, which can suppress the temperature rise effectively and attain the lowest wear rates. The increase of oil volume fraction for the oil-air lubrication led to diminished wear scar depth and low wear rates, while the supplied oil quantity and air pressure were constant, the increase of rotating speed resulted in slight decline of friction coefficient, as well as gradual elevation of temperature and wear rates. Regarding loading, its enhancement made the friction coefficient and wear scar depth went up initially and then reduced, which also caused the wear rates decreased. The findings of this research provide a useful basis for selecting the optimal high-speed bearing lubrication method and their operating parameters.