Analysis Of Spin-slide Thermal Elastohydrodynamic Lubrication Based On Carreau Rheological Model

Thermal elastohydrodynamic lubrication(EHL)problem under spin-slide condition is analyzed based on the Carreau rheological model.The main contents can be divided into four parts: Analysis of thermal EHL with Carreau rheological model and Eyring rheological model.Analysis of non-Newtonian thermal EHL under spin-slide condition.Optimal design of the large end of the roller and the inner rib in a tapered roller bearing based on spin-slide thermal EHL.Effects of oil-supply condition on spin-slide EHL performance by experiment.Firstly,a point contact thermal EHL model based on Carreau rheological model was established,and the influence of rheological parameters on the shear thinning effect was analyzed.The difference between the Carreau and Eyring models with different entrainment speed,load and slide-roll ratio was compared.Results show that,the shear thinning effect with Carreau rheological model is stronger than that with Eyring rheological model.The numerical solutions obtained by the two rheological models are quite different with high-viscosity polymer oil,especially in the case of high speed,heavy load and large slide-roll ratio.Secondly,a non-Newtonian point contact thermal EHL model under spin-slide condition was established,and the temperature field was solved for the spin-slide EHL.The difference of EHL characteristics between isothermal and thermal conditions was compared.Effects of angular velocity,the load,the ellipticity and the spin factor on the spin-slide EHL were analyzed.Results show that,thermal effect can not be neglected under spin-slide condition,which leads to smaller oil film thickness.The increase in the angular velocity,the load,the spin factor and ellipticity leads to the increase in asymmetry of oil film shape.The surface temperature for the moving solid increases firstly and then decreases with the increase in the angular velocity.The EHL numerical solution is affected by the ellipticity in a specific range.Thirdly,based on the structural analysis of the inner rib and the large end of the roller in a tapered roller bearing,the non-Newtonian thermal EHL model considering spin-slide effects between the rib and the large end of the roller was established.Variations in the friction coefficient,the film thickness and the temperature versus the ratio of large end curvatureradius of the roller to the curvature radius of the rib with the two kinds of rib structure were compared.Results show that,the spin motion has little effect on the film thickness and the pressure.There are optimal ratios of curvature radius for the two kinds of the rib structure to obtain the good lubrication state.Finally,on the optical interference spinning EHL test bench,variations in the oil film shape and thickness under various oil-supply condition were investigated.Results show that,under the fully-flooded condition,the increase in the speed,the load,the spin factor and the oil viscosity leads to obvious spin effects.Under oil-starvation condition,the smaller oil-supply quantity may maintain a better lubrication effect.Starvation may happen easily with high-viscosity oil.In addition,sarvation area is different with the oil-supply position due to the spinning effect.When the oil-supply location is selected,fully-flooded lubrication should be satisfiled at the high-speed side.In general,starvation in the spin-slide EHL can be hindered by the spinning motion.