Patent ID: 6178801
Filing Date: 2001-01-30
Classification: B21K,Y10T

Abstract:
A forging device for forming a crown-shaped helical gear, comprising:a die holder having an axially central part bore diminishing in diameter from one end thereof to the other end thereof defining a tapered surface,a finishing die fitted for axial sliding in the axial direction in the axially central part of the die holder, the finishing die having a corresponding tapered surface engaging the tapered surface of the central part bore,twist forming teeth formed on the inside circumferential surface of the finishing die for forming a crown-shaped helical gear with the thickness of each tooth being thinner in a middle part than toward both ends in an axial direction of the die, wherein a half-finished work having an outside circumferential surface with rough-formed twist teeth is brought into screw engagement with the twist forming teeth of the finishing die,a first punch for axially pressing the half-finished work,a second punch for axially pressing the finishing die, anda rotary device rotating the die holder in a direction opposite a direction in which the half-finished work is rotated with the finishing die when the first and second punches respectively press the half-finished work to form the crown-shaped helical gear.