Numerical Analysis Of Elastohydrodynamic Lubrication Of Rolling Linear Guide

Based on the LG-45 rolling linear guide,the elastohydrodynamic lubrication(EHL)performance was analyzed under different working conditions.The contents mainly include four parts: The EHL analysis of the rolling linear guide;The influence of the preload on the lubrication performance of the guide rail;The stiffness of the rolling linear guide and its effects on the lubricating performance of the guide rail;With the Eyring fluid,analysis of thermal spin EHL of the guide rail.Firstly,the EHL model of the LG-45 guide rail was established.The speed analysis of the slider-ball contact pair and the ball-rail contact pair was provided.Effects of parameters,the working condition,and the lubricant of the guide rail on the lubrication performance and lubricating state of the guide rail were discussed.Results show that,with the increase in the contact angle,the film thickness ratio increases at first and then decreases.The ball diameter and the contact angle do not change the lubrication state of the rail pair in this paper.The slider speed and total load have an effect on the film thickness ratio and the lubrication state of the guide rail pair,and the influence of the slider speed is more obvious.Secondly,with the preload of the guide rail pair,an EHL model was established.Comparison of the central and minimum film thickness between the numerical results and those calculated by the empirical formula was made.The influence of different parameters on the lubricating performance of the guide rail was analyzed under the preload condition.Results show that,with the increase in the slider speed,the empirical formula is no longer applicable to the estimation of the film thickness after the preload of the guide rail.As the preload amount increases,the film thickness decreases,the film pressure and the film load capacity increase.When the speed increases,the film thickness,the pressure and film load capacity increase significantly.Thirdly,the stiffness analysis model of the LG-45 guide rail was established.The influence of the ball diameter,the groove curvature ratio and the preload on the contact stiffness of the guide rail was discussed.When the elasticity of the rail system was considered,effects of different parameters on the preload amount and the lubrication performance of the guide rail pair were analyzed.Results show that,the vertical load has an obvious influence on the stiffness coefficient.With the increase in the sliderspeed,the ball diameter and the groove curvature ratio,the preload amount increases to some extent.In addition,effects of the slider speed on the film thickness and pressure are the most significant.Finally,with the Eyring fluid,a spin-thermal EHL model of LG-45 rolling linear guide was established.The influence of parameters such as the contact angle,the ball diameter and the groove curvature ratio,on the thermal EHL lubrication performance of ceramic guide rail was discussed.Results show that,due to the spin,as the contact angle increases,the film thickness increases firstly and then decreases,the film pressure increases,and the film thickness on both sides changes significantly.Therefore,a suitable contact angle can be determined.Effects of the characteristic shear stress and the total load on the frictional coefficient and film temperature are the largest.