Numerical Simulation And Experimental Study On Two Times Offset Spinning Of Connecting Rod Bushing

Connecting rod bushing is an important part connecting piston pin and connecting rod head in the internal combustion engine.It's used to avoid the direct contact between the connecting rod tip and the piston pin and to prevent the stress concentration at the connecting rod tip,so as to protect the connecting rod.When assembling,the bushing was pressed into the small end of the connecting rod through interference fit to avoid the direct contact between the piston pin and the small head of the connecting rod,which can extend the service life of the connecting rod.The connecting rod bushing bears the alternating action of the connecting rod inertia force and the cylinder bursting pressure in the work.Friction,wear,erosion and ablation of the connecting rod bushing can block the oil hole and even cause accidents.Therefore,its performance directly affects the reliability and service life of internal combustion engine.The offset spinning is a spinning method in which several spinning wheels is assembled in different planes,staggered with certain distance in the axial direction,and the thickness of the workpiece is reduced successively in the radial direction.In this way,the production efficiency can be improved greatly.Connecting rod bushing is made by the power spinning process,which can significantly improve the tensile strength and surface hardness and have good mechanical performance.But the multipass spinning can better realize the grain refinement,increase mechanical properties of the products,so as to better meet the needs of high pressure high-power diesel engine.Based on it,researching the influence of process parameters on the stress and strain,deformation uniformity and the mechanical properties,and according to the requirements of the bushing performance,set up a reasonable process parameters.It is of great value to control and improve the performance of the connecting rod bushing and improve the life of parts,and of great significance to promote the spinning technology to the direction of nano/Superfine crystal.In this paper,studying combined numerical simulation and experimental forming a 3d geometric model of cross-spacing spinning by pro-e,and a finite element simulation model of offset spinning on the basis of simufact.forming.Take QSn7-0.2 connecting rod bushing 2times offset spinning as the research object,studying the influence of the main process of power spinning parameters: the total reduction ratio,distribution ratio,the first time feed ratio,the second time feed ratio on the spinning forming quality evaluation indexes: the roundness error,straightness error,diameter tolerance,the influence law of equivalent plastic strain by the orthogonal experiment method.And the significant degree of influence of each process parameter on the forming quality of connecting rod bushing was obtained by the grey correlation degree analysis method.Through the analysis of gray relational degree,the optimal combination of two secondary stagger spinning process parameters of connecting rod bushing was obtained.Then through the comparative analysis of the test,it is concluded that the forming quality of the second spinning of the connecting rod bushing is better than that of the first spinning in terms of mechanical properties,and the second spinning has better mechanical properties than that of the first stagger spinning.