Study On The Influence Of Surface Topography Of Elastohydrodynamic Lubrication Interface Texture On Subsurface Properties

Gear and bearing are widely used in vehicles as basic parts,and their working performance is directly related to the driving comfort and safety of vehicles.With the growing size of the automobile industry and the continuous development of electric energy,hydrogen energy and other fields,the working environment of these parts is more and more complex.How to reduce friction and wear of elastic flow interface has become a key issue to improve the service life of high pair parts of vehicles.In this paper,elastohydrodynamic interface is taken as the research object,and surface texture technology is introduced to explore the influence of texture surface topography on tribological characteristics,as well as the subsurface characteristics of the friction process of the texture surface.Based on the above two purposes,the following contents are studied:（1）Micro-texture with different parameters was manufactured by laser processing method,and the influence of processing parameters on the quality of micro-texture was explored,and the optimal combination of processing parameters was found.By introducing ISO 25178 3D topography parameters,Talysurf CCI Lite non-contact 3D optical profilometer was used to characterize the texture surface.（2）A point contact elastohydrodynamic lubrication model considering the effect of texture surface topography was established.The oil film pressure and thickness distribution on different texture surfaces were calculated,and the influence of texture surface morphology on maximum pressure and minimum film thickness under different loading and enrolling velocity was studied.The results show that compared with smooth surface,the textured surface increases the maximum contact pressure and decreases the minimum film thickness.（3）Combined with theoretical analysis and finite element simulation,the influence of micro-texture with different diameters,densities and depths on the subsurface characteristics of elastohydrodynamic interface was studied.The results show that,under the same working conditions,the texture topography has a significant effect on the stress distribution of the subsurface surface,and the surface texture makes the larger stress area of the subsurface surface closer to the surface.The three-dimensional topography parameters of the texture surface are related to the sub-surface characteristics.When designing the topography parameters of the texture surface such as S_sk,a small value should not be pursued,but should be kept in an appropriate range.（4）MMW-1000 vertical universal friction and wear testing machine was used to test the friction and wear properties of the textured surface specimens.After the friction specimens were washed and dried,small pieces of suitable size were cut along the direction of wear marks by electric discharge wire cutting machine,and the sub-surface structure of the specimens was observed by scanning electron microscopy.The results show that the friction property of the textured surface is better than that of the smooth surface under low load,and the lubrication improvement effect is more significant.The subsurface plastic deformation of the texture surface morphology is more serious,and the overall spalling of the texture surface morphology appears locally,while the smooth surface spalling is less.Therefore,the fabrication of micro-texture on the surface of high pair parts has an adverse effect on the subsurface characteristics and may accelerate the fatigue damage of the parts.At present,surface texture technology is not widely used in high pair parts,because the mechanism of micro-texture for point and line contact is not very clear.The above research can play a certain reference role in the application of surface texture in high pair parts,and provide theoretical support for improving the stress condition of bearing and other parts through surface topography design.