Patent ID: 8196488

Claim:
An apparatus for manufacturing a helical gear, comprising a die for working helical tooth portions of the helical gear as a work piece, a plurality of pairs of lands, each land being formed on a predetermined portion in a tooth direction of each respective opposed working surface on said die, the opposed working surfaces being formed at an incline corresponding to a helix angle with respect to an axial direction of the die, and each pair of lands defining a smaller distance between opposed working surfaces than a distance between other portions of the opposed working surfaces, and a punch for forging said work piece, wherein forging the work piece by the punch causes the helical tooth portions to pass through the lands, thereby causing worked surfaces on both side of said helical tooth portions on said helical gear to be ironed by the lands, and forging the work piece by the punch includes applying a pressure to a face of a tooth profile of the work piece by the punch in a direction that is perpendicular to the tooth profile and that is set at an angle approximate to the helix angle.