Numerical Simulation And Experimental Research Of Cold Net-shape Forming Of Spur Gear

Combined the design method of infinite multistage preforming progressive forming technique with divided-flow principle, an extrusion technology scheme for spur gear is preliminary established. By continuous transition tooth-profile-surface, the metal workpiece is forced to flow into tooth-tip step-by-step, and resisting force of metal flow is decreased, therefore the filling condition is improved and the forming force is reduced. The surface of die cavity was built with CAD software, and the metal flow process was simulated with CAE software. The simulation results show that insufficient corner filling is avoided and the whole gear forming effect is good.Scenario comparison method was adopted to improve the conventional scheme of closed-die forging of spur gear based on mold shape. Two-dimensional simulations are performed in comparison of schemes, which saves a lot of time and decreases the computing cost. The rule of metal material flow in the forming process is discussed in brief, and a conclusion that the distributions of material radical-flow-velocity can be used to evaluate the design scheme is drawn. Finally, a feasible improved schemewith punch end surface in " " shape and die bottom surface in "" shape isput forward.To continue the numerical simulations of the conventional and improved schemes, some key technologies, including geometric model, contact, mesh adapting and remeshing, are solved. By comparison of the simulations results of the two schemes, the main conclusions obtained are as follows: the distributions of stress, strain and radical-flow-velocity are homogeneous in improved scheme; the improved scheme is in favor of improvement of the corner filling condition and decreasing the forming force. A general good agreement was found between simulation and experimental results throughout the study. This further validates the feasibility of the improved scheme.