Study on a new technological scheme for cold forging of spur gears

Insufficient corner filling is one of the main disadvantages of conventional cold closed-die forging of spur gears. To guarantee the dimension accuracy of spur gears, how to improve the filling condition is very important. Because the die shape is one of the most important factors in forming, three design schemes with different die shape are researched in this study. Firstly, finite element method is used to simulate the cold forging process of the spur gear with two-dimensional axisymmetrical model, and the strain distributions and velocity distributions are investigated through the post processor. Radial-flow-velocity distribution is an important indicator to be evaluated, and a relatively better scheme is selected. Secondly, three-dimensional simulation for the relatively better scheme is further performed considering the complicated geometric nature of gear, and the results show that the corner filling is improved and well-shaped gear is forged. Finally, a corresponding experiment is done, which is mainly utilized for supporting and validating the numerical simulation and theoretical investigation.