Cold Extrusion Process Simulation For Flywheel's Inner Ratchet And The Die Design

Cold extrusion is an important method for some gear-type parts. Compared with traditional gear machining method, it can increase raw material's utilization and productivity and reduce the energy consumption, and also can improve their mechanical performance and their useful life. Especially to some parts such as inner ratchets which have complex tooth shape. It is difficult to cut conveniently by machine tool. But, using cold extrusion method, it not only has high productivity, but also have better quality.Numerical simulation of the inner ratchet's cold extrusion process by FEM can get metal flow rule, effective stress and strain distribution in workpiece and load-stroke curve during extrusion deformation. Using numerical simulation method also can predict the defects such as rollovers and puckers, and can reduce the die's trial-and-error cycle, decrease the cost and get the optimized die design.To optimize the process parameters and get a better extrusion process of inner ratchet's cold extrusion process of bicycle's flywheel, orthogonal experiment design and numerical simulation method are used in this text. In the orthogonal experiment design, roughcast's inner dimension, top die's chamfer angle and working straight length are choosed as influence factors, and tooth root's diameter and tooth tip's diameter and load are evaluation criterion. By FEM simulation, the influence of the each factor to extrusion forming is gotten. Based on above results, the optimized three parameters are determined. It gives the basic knowledge about how to improve the quality of inner ratchet's cold extrusion forming. Finally , a die of the flywheel's inner ratchet is designed and physics experiments are performed. The experimental results show the tooth of a inner ratchet by cold extr(?)sion is full, and the metal flow and tooth's fill course are consistent with numeric(?)l simulation. Compared the load-stroke curves of numerical simulation with that of experiment, the curve's changing trend are basically same, it verifies the reliability of (?)(?)numerical simulation result. Based on the above research of the numerical sin(?)(?)(?)ion and experiments, some advices about cold extrusion process's design of inner(?)(?)(?)(?)(?) are presented.