Abstract: The metal flow rule in the conventional cold forging process of spur gear is investigated. Inorder to reduce the friction resistance and improve the non-uniform deformation, radial rigid translation flow mode and axial uniform flow mode are proposed. Based on the rigid translation mode, a novel gear finish forging technology is put forward. From the results of numerical simulation and physical experiment, the hypothesis of rigid translation flow mode is verified. The effect of two key process parameters (the tooth height after preforming and friction coefficient) on forming load is analyzed, and the superiority of the novel forming tech- nology is further proved from the analysis results. To improve the non-uniform flow mode, the novel technology is further improved with unsymmetrical punch. Finally, the peak value of conventional forging process is also simulated to compare the novel forming technology, and the result shows that the forming load can decrease significantly with the new technology.

Key words: Numerical simulation, Resistance of friction, Rigid parallel motion, Spur gear, Uniform deformation