Process Study On Cold Extrusion Of Preform For Motorcycle Starting Gear

With the rapid development of China’s motorcycle industry, it is required that all partsof the production of the industry must be more high-quality, efficient, low-cost,environmentally friendly. Starting gear as a movement and power transmission, is theessential key components in the motorcycle engine. Cold extrusion technology applied tothe processing of motorcycle starting gear, will have broad application prospects. thedifficulty of Motorcycle starting gear preform cold extrusion lies in forming a bore andconvex in the same time, the process is complex, metal flow disorders, stress and strainchanges is severe; mold strength is difficult to guaranteed. the key is to design a rationalprocess so that the metal flow is more uniform, forming force is lower to improve die.According to the structural characteristics of the part, we develop three differentkinds of processes: the Anti-extrusion upsetting-forging process, the compositeupsetting-forging process and anti-extrusion+upsetting extrusion process. on the basis of3D plastic finite element simulation software(Deform-3D), the finite element model ofstartting gear perform for motorcycle is set up, and then we simulate and analyze the threeprocesses, finally get the law of the flow of metal parts during the forming process as wellas stress and strain distribution. the metal flow in anti-extrusion upsetting-forging processis the most complex, using the principal stress method,we infer that the location of theneutral layer of blanks in the formation is affiliated to with anti-extrusion ring of thicknessratio and the friction between the blank and dies. it is observed that parts quality haveinfluence with thickness ratio of ring in the anti-extrusion upsetting extrusion and friction.The recess position which is related to forming load is optimized The forming process inthe anti-extrusion+upsetting process is studied. Compared with the forming load andforming quality of the three process,we get the best process scheme.Finally, according to the theoretical analysis and numerical simulation results,basedon the existing equipment, experimental schemes were worked out. A two layerscombination concave die and special cold extruding die guiding with guide pin and guidesleeve were developed. The process test shows that experiment result is in accordance withthe theoretical analysis and numerical simulation.