Temperature Rise Analysis Of Two-phase Flow In High-speed Angular Contact Ball Bearing Chamber Under Air-oil Lubrication

High speed motorized spindle is a key part of high-speed machine tools, angular contact ball bearings are widely used in high-speed motorized spindles due to low starting friction, high rigidity and reliability. However, heat generation caused by frictional loss has been the main limiting factor for improving the speed and service life of many high-speed ball bearing applications, so bearing lubrication and cooling become very necessary. Oil-air lubrication has become the first choice for lubricating and cooling of high speed angular contact ball bearing due to its excellent performance. Thus, it is very essential to investigate the bearing oil-air lubrication.Based on the theory of bearing heat, the heat mechanism of angular contact ball bearing are analyzed in the conditions of oil-air lubrication, the heating rate and convective heat transfer coefficient are calculated at different speed. A geometric model of the 7006 C bearing chamber is established, the temperature field of bearing chamber is analyzed using fluent in six aspects, including speed, oil supply, gas pressure, the viscosity of lubricating oil, inlet location and inlet number. The results show that(1) The high temperature area of bearing chamber is distributed in the contact area of rolling element and raceway, which is caused by the frictional heat and the stir heat of lubrication oil; The lowest temperature appears in the entrance area, and the highest temperature appears in the exit area where is farthest away from the entrance.(2) With the increase of rotating speed, the temperature in the bearing chamber increased,and the range is more and more obvious; with the increase of oil supply, the temperature in the bearing chamber decreases and then increases, and there is an optimum oil supply.(3) In oil-air lubrication compressed air is used to transfer oil and dissipate heat. Within a certain range, the temperature in bearing chamber is decreased obviously with the increase of gas pressure. With the increase of the viscosity of lubricating oil, the temperature of the bearing chamber is decreased firstly and then increased, and exists the best lubricating oil viscosity.(4) With the increase of inlet number, the highest temperature in the bearing chamber is decreased, but the average temperature is increased. In the case of a certain gas supply, the optimum temperature distribution of the bearing chamber is appeared in the two inlet condition. Furthermore, with the increase of the inlet, the temperature in bearing chamber is relatively average, and the high temperature area reduced. Therefore, increasing the number of entrances and air supply can achieve better results.Comparing with the experimental data, the simulation results are in accordance with the experimental results. The results provide an effective method for determining the best lubrication parameters and designing air-oil lubrication system.