Study On The Influence Of Die Structure On Precision Forging Of Spur Gear With High Boss

In the recent years, the precise plastic forming technology of spur gear is gradually trending toward producing near-net-shaped or net-shaped products directly. This paper mainly deals with the near-net-shaped forming of the typical special gear, playing an important role in mini-car, with big modulus and high bosses.By combining floating matrix and multi-constrained divided flow methods, this paper studies the influence of different structure dies on the precision forging of spur gear with high bosses. Through dealing with a series of key technologies, such as geometric model and remeshing, three forming schemes based on different die structures are simulated by three-dimensional finite element. By comparison of the simulation results of the distributions of stress, strain, velocity and load-stroke curve, the main conclusions obtained are as follows: the two improved schemes, with boss on the bottom die and mandrel constrained structure, are in favor of improvement of the defects of non-balance forming, especially the forming of the bottom boss, and decreasing the forming force. At the same time, through studying the influence of friction factor on the forming of such spur gear, it also found that the bigger of the friction factor, the more different of balance forming.Based on the finite element simulation, the die is modified, and with the material of Pb, the technological experiment on the precision forging of spur gear with big modulus and high boss has been done. The experimental results are in good agreement with the numerical simulation results. It also has been proved that the improved schemes are feasible.