Study On Influence Of Surface Topography Structure On Lubrication Characteristics Of Diesel Main Bearings

The main bearing,which is known for the crucial friction auxiliary material of diesel of all these kinds of things,and its operating cases affects the durability as well as safety of the diesel.With the increasing of the usage requirement,the diesel’s explosion pressure and speed as well as the output power all increase,which lead to increase the dynamic load on the main bearing but deteriorate the bearing lubrication condition.The framework of the surface topography significantly effects the friction and wear peculiarities of the surfaces.Thus,controlling the main bearing surface topography framework reasonably can improve the bearing’s lubrication situation and the diesel’s reliability.Therefore,this paper took the main bearing of the diesel as the studying object,based on the theories of bearing lubrication,and the factors of journal tilt,bearing surface elastic deformation and surface roughness,then according to the flexible monolithic machine,the primary bearing’s elastohydrodynamic lubrication model had been set up.And the impact of the surface topography framework on the lubrication peculiarity of the diesel main bearing had been studied by taking simulation calculating means.The staple analyzing details are as follows:（1）The lubrication characteristics of each main bearing had been considered by working out Reynolds equation with finite difference means with no thinking of the surface profile and surface texture.The results showed that during the course of work for the diesel,in the place which is near the output end,the staple bearing ‘s oil film thickness ranked the smallest,the crest value of rough contact pressure on the friction surface ranked the largest,and the medical value of gross friction energy loss ranked the largest.（2）According to the theory in the area of surface profile,the main bearing lubrication peculiarity had been studied with the effect of the surface profile’s relevant parameters and engine working situations.The results showed that the types of surface profiles had effects.When the surface profile was elliptic,the oil film thickness’ s minimum increased sharply by several times.Meanwhile,the oil film pressure’s maximum enhanced by 6.89%,the maximum rough contacting pressure descended several times and the medial friction loss declined by 15.29%.When the surface profile width and height increased,the variation trend of the main bearing lubrication characteristics were similar.Engine operating cases could have an impact on the lubrication peculiarity of the bearings.（3）According to the theory in the area of surface texture,the impacts of surface texture parameters and engine’s operating situations on the staple bearing lubrication peculiarities had been analyzed.And the outcomes illustrated that when reckoning on the surface texture,the main bearing’s oil film thickness minimum elevated by 5%,the rough contacting pressure’s maximum declined and the medial friction loss descended.When the surface texture was located at the main loading bearing region of the bearing and closed to the ingress of the dynamic pressure lubrication convergence region,the lubrication situation of the main bearing was significantly increased.In addition,the surface texture parameters and engine operating conditions all had influences on the improvement of lubrication peculiarities of main bearing.（4）An improvement project had been designed with considering both in the surfaces of profile and framework.The lubrication peculiarity of the staple bearing under the diverse kinds of improving projects were researched.The results showed that when a reasonable improvement project was adopted,compared with no amendment,only reckoning on the surface profile and surface texture,the main bearing’s oil film thickness minimum illustrated an overall increasing trend in one working period of the engine and the oil film thickness minimum respectively elevated by 194%,2% and 140%.The maximum oil film pressure respectively increased by 100%,67% and 60%.The maximum rough contact pressure respectively decreased by 83.95%,5.6% and 80.56%.The average friction loss respectively decreased by 32.19%,5.8% and 6%.