Research On Cold Extrusion Forming Technology Of Input Shaft Of Truck Transmission

As the key transmission and steering parts,the role of spline shafts,used in automobile and motorcycle industry,become more and more important.At present,the technology of the cold extrusion forming of spline shafts in small and medium-sized spline,such as motorcycle’s splines,have been relatively mature.But for the large automobile splines,they are also produced by traditional machining in China,which has low productivity and material utilization.For this topic’s research –the cold extrusion forming of big spline shaft,the main problem is as the spline shaft belongs to the multi-step and long shaft parts,the open-die cold extrusion is the only method to be used.And the premise of achieving the process is the forming force should be less than the instability yield strength of the force transmission section of the blank,otherwise there will be forming defects such as local upsetting instability and bending deformation.So how to reduce the forming force effectively,improve the quality of the spline shaft and the die life are the key of the open-die cold extrusion forming of the large spline shaft.The research object of this topic is a truck transmission input shaft,a new product that a company plans to develop.In this article,the method of open-die cold extrusion forming of spline shaft had been proposed.According to the structure characteristics of the input shaft,the process of the cold extrusion was developed.With the help of the finite element analysis software DEFORM-3D,the forming process of the open-die cold extrusion of spline shaft was simulated.What’s more,the main factors that influenced the forming limit of input shaft spline,the influence law of the ultimate deformation degree that came from different factors and the law of metal flow in the process of forming were obtained.At the same time,the various process parameters of the open-direct extrusion of spline shaft were studied,and the influence law of the various process parameters on forming force and forming quality were got.And the process parameters were optimized through the orthogonal experimental design and the optimum technological parameters were determined.Based on the numerical simulation results,the process test of the open-die cold extrusion of input shaft spline was done.And the test results show that reasonable die structure parameters can reduce the forming force effectively on the condition of guarantying the forming quality.And the quality of cold extrusion specimen is better,which can meet the design accuracy.The process test verified the correctness of the numerical simulation results.