Study On Stamping-forging Forming Process For Car Clutch Hubs With Gear Shape

As the development of technology, it’s becoming more and more required fornear-net shape in plastic forming. It’s an important issue to reduce weight and energyconsumption, save material and improve mechanical properties. This makes some keycomponents in automobile and aerospace industry much more integrated, complex andlight weighted. For sheet metal forming, there are numerous components with largesurface area and different wall thickness. It can not only improve forming precision andmechanical properties of the parts, but also can realize high material utilization and highproductivity, if stamping-forming hybrid plastic forming is used.The car clutch hub with gear shape is a critical component of automobile with largesurface and quite different wall thickness in different locations. The stamping-forgingforming processes as well as the forming die were studied and designed for the car clutchinner hub and outer hub in this research. First, the process flow including blanking,piercing, deep drawing, re-striking, ironing, trimming and side piercing was designedaccording to the features of the hubs, and the process parameters were calculated. Inparticular, three different cases of the process for forming the gear shape were proposed:drawing with ironing and then the gear shape is formed by ironing; the sidewall isformed by ironing twice; the sidewall is formed by ironing only once. Then differentstamping-forging forming processes were analyzed by FEM software. The results haveshown that the formed part is with more accurate size and uniform sidewall thickness inthe case sidewall formed by ironing twice. Finally, die for stamping-forging formingprocess was designed. In order to improve the strength of die and save material,three-layer composite structure was used. And there was an approach angle of die toavoid fracture when the material flows through the round corner. Moreover, FEsimulation was used to calculate the stress distribution of the die. It was found that therigidity of the three-layer composite die was quite good and safe to use.