At present, the main problems faced by the development and wide application of cold extrusion technology of spur gears are as follows:
1) It is difficult to fill the tooth shape and the die is seriously worn
Because the metal flow in the cold extrusion process of spur gear is very complex, the material has high deformation resistance in cold state, poor fluidity and low filling capacity, which leads to the difficulty of filling the corners of the concave model cavity. The cold extrusion method makes the die in the limit machining state, which brings the disadvantages of easy wear, serious elastic deformation and low service life.
2) Low production efficiency
During forward extrusion, due to the large friction between the wool return and the die cavity, the flow velocity of the wool return surface, layer and core is inconsistent, resulting in serious “shrinkage” at the end of the wool return. Due to the existence of “shrinkage” phenomenon, it is difficult to realize the continuous production of spur gears.