Molding method for geared member with boss and geared member with boss

摘要

A method for molding a gear member (2) with a boss (6), includes: (a) molding a boss portion (6) by performing a backward extrusion process for one end of a predetermined raw material (10); (b) molding a chamfer portion (P) by performing a forward extrusion process for the other end of said raw material (10); and (c) molding a gearing portion (8) in which a plurality of teeth (8a) continuously from the chamfer portion (P) toward the one end are molded by performing the forward extrusion process for an extrusion residual area of the raw material (10) having passed through the step (a) and (b). The predetermined raw material (10) is constructed as the gear member (2) with the boss (6) in which the boss portion (6) is molded at the one end and the gearing portion (8) is molded continuously from the chamfer portion (P) at the other end by passing through the steps (a)-(c).