| 摘要 |
PURPOSE:To prevent a thick walled part from being formed in a product and improve a working property by bringing the tapered faces of both the inner peripheries of the annular projection of a molding punch and the clearance groove of a cup-like stock into contact with each other in a method of molding a bottomed internal tooth profile. CONSTITUTION:A stock 7 is set in a die 3 having a throttle part 3a in its inner periphery. The stock 7 is held in between a molding punch 5 having a tooth profile 5a on its outer peripheral face from the bottom part and a pushing punch 6 and, as it is pushed down, an internal tooth profile following the shape of the tooth profile 5a can be obtained. An annular projection 9 is provided on the peripheral edge part of the end face of the molding punch 5, a clearance groove 10 is previously formed on the hole bottom of the stock 7, the inner peripheral face of each of the projection 9 and the groove 10 is formed into a tapered shape, and the tapered faces 9a, 10a are brought into contact with each other. That is, by taperedly fitting the projection 9 and the clearance groove 10, the centering between the stock 7 and the molding punch 5 can be easily and directly carried out, enabling a highly accurate internal tooth profile without a thick walled part to be molded while also improving a working property.
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