Patent ID: 7612310

Claim:
A manufacturing method of a molded gear having a plurality of teeth, each being provided with a chamfered portion shaped by providing a slope in one end edges of the tooth, wherein the manufacturing method comprises: the steps of: performing electrical discharge-machining of a metal member having a thickness smaller than a dimension of a tooth width of the molded gear by moving a first discharging electrode that is formed to have the same shape as a cross-sectional shape taken perpendicularly to a rotation axis of the molded gear while penetrating the metal member in a direction of thickness thereof until a gear piece is formed to have a hollow portion the same in a shape thereof as the molded gear; performing electrical discharge-machining of a different metal member only a predetermined depth in a direction of thickness of the different metal member by moving a second discharging electrode that is formed to have a shape the same as a cross-sectional shape taken perpendicularly to the rotation axis of the molded gear and also to have a chamfered slope portion the same in a shape thereof as the chamfered portion of each tooth on a tip end of the second discharging electrode until a chamfer-application piece having a recess portion the same in a shape thereof as the chamfered portions of the molded gear; bringing the hollow portion of the gear piece and the recess portion of the chamfer-application piece to be in registration with each other and subsequently connecting the gear piece to the chamfering piece to thereby assemble a molding die; and manufacturing a molded gear by molding a gear forming material by using the assembled molding die.