The Fomring Analysis Of Gear And Die Optimization In Cold Extrusion

China’s Eleventh Five-Year Plan，which laid down that the unit GDP energyconsumption must be reduced by20%，with major pollutants emission reduced by10%. Traditional manufactures of spur gears are cutting and forging，which are lowefficiency，high energy consumption and low accuracy. Cold extrusion which makesit possible to be net-shaped and formed at room temperature is one meaningful wayfor energy-saving and emission reduction. Thus it’s very necessary to improveprocess design leves，forming qualities and optimize die structure designs of coldextrusion for spur gear parts.The process and the principle of FEM were analyzed. Three main methods ofcold extrusion for spur gear were simulated to get merits and demerits of each method.The relationship between deformation rates and gear geometry parameters werecertificated theoretically. Influences of different numbers of modulus，teeth，gearradius in processes of spur gear cold extrusion were simulated on the basis of thistheory，as well as influences of different elements shape，roughcast symmetries on theaccuracy.According to results of parameters analysis，the integrated process whichincluding forward extrusion and shaping extrusion were put forward，and spur gearswith bigger modulus and more teeth could design by optimizing die structures.Compared with traditional cold extrusion process，70%-80%load are reduced and thefilling results are improved completely. The main factors that affect gear geometry changes in size are the elasticdeformation of dies and the elastic recovery of parts. Based on spur gear partsparameters in practice，calculate the compensation in design size of integratedextrusion die and verified to produce qualified spur gear parts. Comparison results ofthe metallographic experiment and the numerical analysis reflect relationshipsbetween grain size and strain and hardness distribution of spur gear by cold extrusion.