Analysis Of Grease Flow And Thermal Characteristics In Grease Lubricated High-Speed Angular Contact Ball Bearing Cavity

High speed angular contact ball bearing is the core supporting part of high-speed spindle,grease lubrication is one of the main lubrication methods of the bearing.because the grease has the characteristic of bleeding,it can continuously supply lubricant to the nearby friction pair,which has certain protective effect on the friction pair surface.Especially in high-speed working condition,if the distribution of grease in the bearing cavity is reasonable,which can effectively prevent the bearing wear.Therefore,the analysis of the grease flow and the temperature characteristic of the angular contact ball bearing has important theoretical significance and application value.Based on the computational fluid dynamics method the analysis model for the grease flow in bearing cavity is established,the flow field characteristics in grease lubricated bearing cavities is analyzed in detail.The results show that,in the case of inner ring rotation,grease is mainly distributed in the space on both sides of the outer raceway,and its flow speed is low;some grease adheres to the inner side of cage with high speed;with the increase of bearing rotation speed,more grease is distributed over the both sides of the rolling elements along the outer raceway,grease between the inner raceway and cage is reduced;with the increase of grease viscosity,cage width and grease filling amount,the grease distribution inside the bearing cavity became relatively uniform,which is beneficial for bearing lubrication.However,in general,due to the effect of centrifugal force,the lubricant is thrown off the outer raceway,resulting in sufficient lubrication of the outer race and insufficient lubrication of the inner race.When the outer ring rotates,in the bearing cavity,a large amount of grease accumulates on both sides of the inner ring and the outer ring,which is more favorable for the replenishment of the raceway oil film.On the basis of the analysis of the grease lubrication flow field of the angular contact ball bearing,the thermal analysis model of the experimental bearing is set up,and the thermal field of angular contact ball bearings is analyzed by using thermal-fluid-solid coupling method.The bearing temperature characteristics is analyzed at different rotational speeds,the results show that: as the speed increases,the surface heat transfer coefficient of each component in the bearing cavity is increased.Among them,the surface heat transfer coefficient of the outer ring grows fastest,the ball is the next,and the inner ring is the lowest.The surface heat transfer coefficient is largest on both sides of the outer raceway with concentrated grease distribution.In the process of bearing temperature transfer,the grease absorbs more heat,and it cannot be ignored.Finally,the feasibility of the simulation model was verified by comparing the simulation values and experimental values of the temperature rise of the bearing inner ring.