PURPOSE: To form a gear having a high accuracy with a high yield by forming a sizing tooth form on the upper side of a forming tooth form of a lower die, and executing a finish working at the time of parting of a forged gear.
CONSTITUTION: A forming billet C packed between an upper die and a lower die 5 is compressed by a main punch 1, and therefore, a shaft hole is formed by butting hollow part forming punches 3, 4 from the upper and lower directions. Subsequently, parting of a forged gear is executed by making a knock-out punch 2 ascend. At the time of this parting, the tooth part of the gear C slides in a sizing tooth form 5b of the lower die 5, a deformation caused by contraction in case a temperature drops is corrected, the gear C having a high accuracy is formed, and a yield is raised.
IIFUSHI JIYUNICHI
HIASA YUKIO
NOMURA SEIJI
DOUHOU TAMENARI
RYOMEI GIKEN KK