Analysis On Lubricating Flow Field And Rolling Element Oil Film Integrity Of High Speed Angular Contact Ball Bearings

The angular contact ball bearing is an important supporting element in the high-speed rotary structure,and the oil injection lubrication is an important lubrication mode when the angular contact ball bearing operates at high speed.During the high-speed operation of the bearing,the rolling element contacts with the inner and outer raceways and cages,and the relative speed of the contact area is high.If the lubrication of the contact area is insufficient,the wear of the internal component surface will be accelerated.Therefore,it is of great significance to study the adhesion characteristics of the lubricating oil on the surface of the bearing roller under working conditions to improve the running performance and service life of the bearing.Based on the bearing lubrication theory and computational fluid dynamics method,this paper takes SKF7005C angular contact ball bearing as the research object.By establishing the dynamic simulation model of oil air two-phase flow in the cavity under the oil injection lubrication condition of the bearing,the adhesion phenomenon of lubricating oil on the surface of the rolling element is studied.It is proposed that the integrity of the rolling element oil film is taken as the standard to evaluate the bearing lubrication performance,and the speed The influence of fuel supply pressure and injection angle on the oil film integrity of rolling element.The results show that:(1)During the operation of the bearing,the oil film integrity of the rolling element surface gradually increases with time,and tends to be stable after a certain time;Influenced by the contact position between the rolling element and the inner and outer raceways,the oil film first presents a circular distribution at the maximum diameter of the rolling element,and starts to expand to both sides with the increase of lubricating oil,finally forming a stable oil film of the rolling element.(2)Rotating speed,fuel supply pressure and injection angle are important factors that affect the oil film integrity of rolling element.Within the range of rotating speed[2800040000]r/min,the increase of rotating speed leads to the continuous decline of the oil film integrity of rolling element,and finally tends to be stable;Within the range of oil supply pressure[0.15,0.45]MPa,the increase of oil supply pressure leads to the continuous increase of the oil film integrity of the rolling element,and finally tends to be stable;Within the range of injection angle[-80,80]°,with 0° as the benchmark,the oil film integrity of the rolling element continues to increase as the injection angle changes to both sides.However,when the angle changes too much,the oil film integrity of the rolling element will drop sharply,and the positive and negative changes of the angle have basically the same impact on the oil film integrity of the rolling element.(3)By analyzing the regression equation between the oil film integrity of the rolling element and the rotating speed,oil supply pressure and oil injection angle,it can be concluded that there is gas vortex on both sides of the rolling element during the high-speed operation of the bearing,which will prevent the lubricating oil from entering the bearing lubrication area;The higher the running speed of the bearing,the greater the eddy current speed,the stronger the blocking effect of lubricating oil entering the lubricating area,and the lower the oil film integrity of the rolling element;With the increase of oil supply pressure,the incident intensity of lubricating oil entering the bearing cavity becomes larger,and the lubricating oil is easier to enter the lubricating area of the bearing cavity through the eddy current,which makes the oil film integrity of the rolling element increase;There is a moment when the oil injection nozzle is directly opposite to the clearance between two rolling elements during the running of the bearing.The increase of the oil injection angle can improve the utilization rate of lubricating oil during the clearance period of rolling elements,thus increasing the oil film integrity of rolling elements;However,if the angle is too large,the lubricating oil will directly flow out of the outlet after hitting the outer wall,and the utilization rate of the lubricating oil will rapidly decrease,which will also reduce the oil film integrity of the rolling element.