| 摘要 |
PURPOSE: A production method for a pinion gear of a seat belt and a molding device thereof are provided to improve the durability of the pinion gear, to equalize the size of the pinion gear, to promote work efficiency and to accomplish the mass production of the pinion gear. CONSTITUTION: A disc(106) of a desired size is obtained by blanking a board(107). A vent hole(105) is pierced on the disc by performing a drilling work. The disc having a vent hole or the disc in a blanking process is inserted in upper and lower dies. Plural 1/2 hemispherical grooves(104) are molded on the outer circumference of the disc by the pressurization of the upper and lower dies. An outer circumferential face of the molded disc is removed by a trimming work. At the same time, an uneven portion(103) is formed in the center of the molded discs by the trimming work. Then, the two processed products are faced each other and the 1/2 hemispherical grooves are welded by a welding portion(102) to be formed into a perfect hemispherical groove.
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