Patent ID: 7347076
Filing Date: 2008-03-25
Classification: B21K,Y10T

Abstract:
1. A forging method for forming a helical gear using a helical gear forging apparatus, the helical gear forging apparatus comprising: a gear die having a gear teeth forming section defined at an inner circumference thereof for forming gear teeth of the helical gear; a collar die integrally formed at an upper end of the gear die; a lower die located below the gear die; a punch located above the collar die and adapted to push a stock into the collar die; and a knock-out located below the lower die and adapted to discharge the molded stock to the outside, the method comprising the steps of: a) smoothly introducing the stock into the gear die via a rounded portion defined in an uppermost region of the gear die adjoining a lower end of the collar die; b) filling the stock in a forming introduction portion of a gear teeth forming section defined in the gear die, the forming introduction portion being patterned with a connection upper-surface groove, a connection lower left-surface groove, a connection upper left-surface groove, and a connection right-surface groove to form a shape with a four-sided cross section; and c) forming the gear teeth of the helical gear in a main forming portion downstream of the forming introduction portion with high accuracy.