Production manner of gear formation die for hammering and formation manner null of the gear product due to gear formation

摘要

PURPOSE:To manufacture a gear forming die having high strength and high accuracy teeth by taper-fitting a cylindrical preform into a die hole through its outer peripheral surface and forcing a master gear having gear teeth on the outer peripheral part from the upper part into the axial center part. CONSTITUTION:The preform 1 forming a hole 2 of the axial center part in equal diameter and an outer peripheral surface 3 which is smaller in diameter to the lower part is taper-fitted into the 1st die hole 11 of the 1st die 10 through its outer peripheral surface 3. A 1st master gear 15 is lowered through a ram to force gear teeth 16 into the hole 2 of the preform 1. An intermediate gear forming die 5 having gear teeth 6 is formed by a compression force to the inside in the radius direction through this 1st die hole 11 and by a pressure to the outside in the radial direction through the gear teeth 16. Thereafter, this intermediate gear forming die 5 is compressed by the 2nd master gear teeth to obtain the gear forming die having high strength and high accuracy teeth. The intermediate gear product is compressed by this gear forming die in the axial direction to obtain a gear product having high strength and high accuracy teeth.