Study On Test Method And Adhesion Performance Of Connecting Rod Bearing Bush Of Diesel Engine

Crankshaft-bearing bush is one of the most important pairing pairs of diesel engine.Its reliability plays a vital role in diesel engine.Especially,with the increasing power of diesel engine,the working environment of crankshaft-bearing bush pair is more demanding,which leads to the increase of bearing bush adhesion tendency.Therefore,it is very important for the further improvement of diesel engine reliability and power density to analyze the reasons of bearing bush adhesion,study the anti-adhesion performance of bearing bush and establish the test method to evaluate the anti-adhesion performance of bearing bush.In view of the above problems,this paper makes the following main research contents:1.Set up the friction and wear testing machine of bearing bush.The speed of the testing machine can be adjusted within 0-3000r/min,the load can be adjusted between 0-30 tons,the oil temperature and oil pressure can be adjusted according to the needs of the test,the torque and temperature and other test data are collected in real time,the test process is stable,which can provide a good platform for the bearing bearing adhesion performance test.2.Two test methods,step-by-step loading method and oil breaking method,were explored,and the oil breaking method was finally determined to evaluate the anti-adhesion performance of bearing bush quickly and stably.The adhesion resistance tests of ternary plated bearing bush,groove bearing bush,ternary plated bearing bush,PVD bearing bush and molybdenum disulfide bearing bush were carried out.The adhesion resistance of five kinds of bearing bush was analyzed and the adhesion resistance of five kinds of bearing bush was obtained.The order of adhesion resistance was ternary plated bearing bush > Grooved bearing bush > Binary electroplated bearing bush > PVD bearing > Molybdenum disulfide bearing bush.At the same time,the adhesion process of the bearing bush is analyzed,and the influencing factors of the adhesion reason of the bearing bush are obtained.3.The finite element ANSYS is used to calculate the stress distribution of dry friction contact between the shaft and the bearing bush under the condition of oil failure.The shear stress and equivalent stress of the bearing bush composed of three different main elements,Al,Sn and Pb,are analyzed and compared.The maximum shear stress of Al is about 3 times larger than that of Pb and 2 times larger than that of Sn.The equivalent stress and shear stress of Pb plating are the minimum,which explains that the anti-bite performance of ternary plating bearing bush(the main element of the coating is Pb)is the best from the material level.The simulation results are compared with the experimental results,and it is concluded that the occluding position of the test is the same as the maximum shear stress distribution position obtained by simulation.