Based on the open die forging of spiral bevel gear, a new type of precision forging die without flash is designed. The mathematical models for solving the forging forming force of open die forging and non flash die forging of spiral bevel gear are established by using the combination method of principal stress and upper bound and deformation work method respectively. The precision forging process of spiral bevel gear is numerically simulated by using the finite element analysis software DEFORM-3D, and the forming process parameters are optimized. The main conclusions are as follows:
1) The new die for precision forging of spiral bevel gear without flash has novel structure and advanced principle. The formed forging has no flash, which overcomes the problems of excessive forging force, insufficient tooth shape filling and low material utilization rate of open die forging.
2) The forging forming force obtained by numerical simulation is consistent with the results solved by the mechanical model. The forming force of precision forging without flash is 11.9 million n, which is more than 60% lower than that of open die forging.
3) The distribution of velocity field, strain field, stress field and temperature field in different stages of precision forging without flash of spiral bevel gear is obtained by numerical simulation, and the flow law of metal is revealed. The effects of initial forging temperature, deformation speed and friction conditions on the precision forging of spiral bevel gear are analyzed, and the optimal forming process parameters are determined: the initial forging temperature is 1150 ℃, and the average working speed of the press is 200mm / S. in the forming process, good lubrication conditions between the blank and the die are ensured to reduce the adverse effect of friction.
4) The numerical simulation results of precision forging of spiral bevel gear without flash are consistent with the process experimental results. The spiral bevel gear forging produced by the new precision forging die has good forming, full tooth shape, excessively smooth tooth root, no collapse, folding and other defects, and meets the application requirements.
The forging die design, computer-aided design, numerical simulation and other related methods used have certain universality, and can provide reference for forging forming analysis and die design of other gear parts.