Theoretical Analysis And Experimental Study On The Influence Of Surface Micro Texture On Lubrication Characteristics Of Journal Bearing

With the development of mechanical equipment in the direction of high speed,large power and heavy load,it is important to improve the tribological properties of friction pairs in mechanical systems.With the continuous development of machining technology,surface micro texture processing technology originated from bionics has gradually become an important optimization way to improve the performance of friction pairs.The main mechanism of the effect of surface micro texture structure on friction performance of friction pairs is shown in three aspects:under the condition of fluid lubrication,the micro dimple structure can effectively produce hydrodynamic lubrication effects;under the condition of mixed friction,micro dimples can be used as micro oil tanks to make lubrication more effective;the worn abrasive particles can be stored effectively,and the occurrence of second wear can be reduced under the condition of boundary lubrication and dry friction.The journal bearing is mainly takes as the research object,and the dynamic pressure effect of the micro texture is analyzed by the establishment of the fluid equation for the micro-textured journal bearing,then the finite element model of three dimensional journal bearing oil film is established to analyze the effect of different working condition parameters and micro texture geometric parameters.Finally,through the friction and wear experiments,the wear reduction law of the micro texture on the surface of the friction pair was analyzed in the actual working condition.The main contents are as follows:Firstly,the fluid lubrication equation of infinitely wide journal bearing with micro texture is established.The influence rule of micro texture depth,coverage rate and other parameters is analyzed through the oil film pressure distribution equation and bearing capacity equation.The fluid lubrication theory shows that the dynamic pressure effect of the micro texture can effectively improve the lubrication performance of the bearing.Secondly,through the establishment of two-dimensional micro textures finite element model of different shapes,the dynamic pressure effect of micro textures with different shapes is analyzed and studied.The results show that the micro textures can effectively improve the bearing capacity of the oil film,and the effect of the rectangular and triangular micro textures is most effective.What's more,the three-dimensional finite element model of micro texture journal bearing is established by gambit,and the lubrication characteristics of journal bearing under different operating parameters and different texture distribution parameters is analyzed.The characteristics of oil film cavitation area of journal bearing considering the cavitation effect are compared and analyzed.The results show that the effect of micro texture on the outlet position of oil film convergence gap is most obvious.Finally,using the universal friction and wear test machine to carry out the friction experiment,the effect of the wear reduction of the micro textures of different layout under the different working conditions is studied.The experimental results show that the radial groove micro textures and the concave micro textures can play a significant effect on reducing the wear.The existence of micro texture can also store the lubricating medium and wear abrasive particles,reduce the two wear of the friction pair,and obviously improve the friction performance of the friction pair.