Research On Strength And Life Of Cold Extrusion Die For Spur Gear Of Truck

Gear is the most common transmission part of the automotive and mechanical field.Most of the main transmission parts of the automobile and equipment are gears.Spur gears are the most widely used in gear transmission.At present,spur gears is mainly processed by traditional cutting,which not only labor time,material utilization is low,the cost is higher.Under the current fierce market competition,the traditional processing methods have been unable to meet the requirements of low energy consumption and high quality,and cold extrusion process because of its high quality,high efficiency,energy saving significant advantages,began to widely use in spur gear processing.In the cold extrusion process of the gear,the die carries a large unit of extrusion pressure,the die is also subject to greater circumferential tensile stress,even if the three layer combination die,the die core is also easy to break.The problem of rupture of the cold extrusion die of the spur gears seriously hinders the popularization and application of the cold extrusion technology in the gear forming.Therefore,how to avoid die rupture,improve the die strength and life is the key to the study of cold extrusion.In this paper,the wheel reducer planet gear of truck is the research object,put forward the continuous extrusion of cold extrusion process,and uses the traditional experience design of combination die for cold extrusion forming numerical simulation analysis.Based on changeable interference combined die failure analysis,the design method of changeable interference combined die are proposed,through the study of this method,the design method of the localized changeable interference combined die is put forward,and carried on the thorough study of the method.The size of the combination die is optimized by the response surface method,give full play to the performance of the material,and the reasonable size of the die is established.According to the law of gear metal flow and die stress distribution,the effects of various process parameters on gear forming quality,die stress and die temperature were studied.According to the results of the finite element numerical simulation for spur gears with cold extrusion process test and production application.The experimental results show that the forming quality of the spur gear is better.Die life of up to 150,000 pieces,the die is in good condition.Extruded part of common normal line length within the design requirements.The method of changeable interference combined die and the optimal design of the combination die can improve the life of die.Test results show the validity of the numerical simulation results.