METHOD AND DEVICE FOR EXTRUSION MOLDING OF HELICAL GEAR

摘要

PURPOSE:To produce efficiently a helical gear by continuous extrusion molding at a good yield by inserting a cylindrical blank material into a die having internal helical teeth and pressurizing the material by a sleeve punch having concentrically a spline-shaped mandrel. CONSTITUTION:Another cylindrical blank material 31 is inserted into the die 22 having the internal helical teeth 22a while the cylindrical blank material 30 formed with the helical teeth 30a to the mid-way is held inserted therein. The formation of the helical teeth 30a of the lower material 30 progresses when the mandrel 28 having the spline-shaped outside circumference and the sleeve punch 26 are lowered. The material 30 rotates during this formation and the mandrel 28 is rotated via the splines 30b, 28d until the formation of the teeth 30a ends, when the helical gear 30 is extruded to the outside of the die 22. The helical teeth 31a are formed at the same time on the outside circumference of the upper material 31. The continuous production of the helical gear is made possible by the above-mentioned method without requiring machining.