Experimental Study On Impact Of Surface Roughness On Journal Bearing’s Lubrication Characteristic

Journal bearing is a rotating shaft supporting element which is operated under journal friction,and has prominent features of large bearing capacity,small power consumption,impact resistance,vibration resistance,high running precision and so on.Because of the simple structure,easy disassembly and other advantages,journal bearing is widely used in some rotating machinery of special occasions.Although there are many studies on journal bearing,the effect of surface wear on the lubrication properties of journal bearings is usually neglected.In the actual work,the bearing surface can not be completely smooth,and the working environment is different,the bearing wear state of lubrication of the journal bearing static characteristics will have different effects.Therefore,it is necessary to study the static characteristic parameters of the oil film and the surface characteristics of the bearing,which has important theoretical basis for the design of the journal bearing and the analysis of the failure form.Based on the theory of hydrodynamic lubrication and the stochastic rough model proposed by H.Christensen,the finite difference method are used to solve the Reynolds equation.In the roughness and no roughness of the journal bearing lubrication under static characteristics were analyzed,the curves of oil film bearing capacity,end leakage flow and friction power were obtained.At the same time,the following conclusions can be drawn: under low speed and light load condition of rough bearing without considering the roughness,the bearing capacity,the end leakage flow and the friction power of the oil film increase with increasing rotation speed of the journal and increase with increasing eccentricity.When the surface roughness is taken into account,the oil film bearing capacity and friction power consumption of the longitudinal rough bearing and the transverse rough bearing increase with the increase of the roughness,the end leakage flow of the longitudinal rough bearing decreases with the increase of the roughness and the end leakage flow of the transverse rough bearing increases as the roughness increases.Based on the theoretical research,the static characteristics of the oil film of the journal bearing are analyzed,and the experimental study is carried out considering the different bearing conditions,the journal bearing with different roughness values(Only the longitudinal roughness direction is considered).The test focused on the axis of the trajectory,oil film bearing capacity and temperature testing and research.The results show that the simulation results are in good agreement with the experimental values.As the load increases,the friction power increases gradually.Under the same load,the larger the roughness is,the higher the friction power is,but the influence is extremely small.On the basis of theoretical research,this paper set up a test-bed and test analysis,which enriches the theory of friction and wear of journal bearing,and provides some reference for the research of journal bearing and floating ring bearing.