Research And Optimization Of The Precision Forging Process For Shifting Gear Blank By The Numerical Simulation Method

Shift gear blank is one of centrosymmetric circle cake forging part, which is animportant transmission part of gearbox for motor vehicle.compare with straightgear,helical gear and bevel gear,Shift gear blank need special strength and fatiguelifetime and position accuracy.beside it’s rib is deep and narrow, therefore it’s a forgingpart whose difficulty coefficient between commom gear and gear blank.with rapiddevelop of china’s mechanical equipment industry, the demand of gear is more andmore.and the quality is required more and more highly.however,because ofenterprise development’s imblances, production quality is irregularity. For thetime,forging parts often have some defects,such as unfilled and folded and lowerposition accuracy,which restrict the development of gear precision forging technology inchina.There are two processes in the precision forging for gear at present,one is openforging,another is closed forging.open forging technology develops early but isgradually substituted because of processes miscellaneous, more flash,materialutilization lower,high energy consumption.closed forging not only has higher materialutilization,but also need lower tonnage equipment and obtains better formingeffect.however,the technicians in many enterprises also take some mature experienceas design rule.try mould cycle is long,the cost is high, the energy consume more.besidethe method can’t consider the various factors which influence the forming effect. Asresult,the design is far different than the practical situation.enterprises got enormousloss.The paper takes three grades shift gear blank of qiu tian limited company inchongqing as research object,through deep study on the forming defects in the originalprocess, and put forward a kind of new die structure named the stepped divide top dieand lower die with ribs’ groove base on divide method.besides,this paper establishesFinite element model of original process and divide process by the simulation softwareDEFORM-3D and analysis the advantages and disadvantages of two schemes.The effectof the ribs of forging parts is very good by optimize the mould structure parameterssuch as drafting angle，round corner radius,boss hight and so on.The results show thatforming loads of pre-forging and finish forging decrease by40%and20%.At theend,The trial-production for shift gearsblank in press show that the above defects are eliminated and positional precision and the products are improved significantly andverify the reliability of the numerical simulation.Form the study,this paper combines the finite element simulation technology withthe precision forging for shift gear blank and researches the reason of thedefects inpractical production.and optimizes the forming load base on divided method.As aresult,key technical difficulties in closed forging for shift gear blank are solved.Thisresearch provides technical support and theoretical guidance In the other round closedforgings.