Study Of Thermo Elastohydrodynamic Lubrication Based On The Dynamics Of Rolling Bearing

At present, most of the researches on elastohydrodynamic lubrication (EHL) andthermal researches of rolling bearing are independent.Researches on EHL of rolling bearingare limited to the single contact spot, without considering the effect of bearing’ssizeparameters, dynamic factors and operating conditions; due to the numerical complexity,when calculating power losses and temperature rise of bearing, simplified calculations areusually used without considerating the complete thermal EHL.In this study, thequasi-dynamic analysis model of angular contact ball bearing and TEHL are combined toanalyse the power losses and temperature rise in high-speed angular contact ball bearings.The main research contents and conclusions of the dissertation are as follows:Supposing the temperature distribution is parabolic across oil film thickness, the heatflux is continuous at the solid-liquid interface, a comprehensive thermal model of mixedlubrication is established, which includes the heat convection, heat conduction,compression heating and shear heatingsimultaneously. The moving point heat sourceintegration method and reduced energy equation are used to determine the temperaturedistribution of contact surfaces and oil film iteratively.The results show that, the convectionand compression of lubricant have an ignorable effect on the temperature when theentraining velocity is very low; however, the effect gradually becomes strong atinlet whenthe entraining velocity increases; surface roughness has significant effect on pressure andtemperature distribution of the lubricated contact area.The non-Newtonian thermal elastohydrodynamic lubrication model with spin motionis established, and robust solution algorithm is developed. It is shown that the temperaturedistribution and film thickness are significantly affected by the spin motion, and the effectof spin on temperature distribution of lubricant film is closely related to slid-roll ratio.The quasi-dynamic analysis model of angular contact ball bearing and TEHL arecombined together to analyse the power losses and temperature rise in high-speed angularcontact ball bearings. In different location of the bearing, the slid-roll ratio and maximumHertzian pressure of the contact affect the sliding power losses; the spinning speed and maximum Hertzian pressure of the contact affect the spin power losses as well. The rotatingspeed and loadon the bearing have significant effects on the power losses and temperaturerise.A temperature measurement apparatus of ball on disc contact is established based onthe infrared technique.The experiment shows that the temperature of the disc surface riseswith the increase of the load, entraining velocity and slid-roll ratio, which is in agreementwith numerical simulation and verifies the developed thermal EHL model.