FORGING METHOD, CLOSED FORGING DIE, AND TRIPOD-SHAPE CONSTANT-VELOCITY UNIVERSAL JOINT

摘要

PROBLEM TO BE SOLVED: To provide a forging method and a closed forging die, capable of reducing the closing force loaded on a die and using a comparatively small-sized closing device for a large-sized product, and to provide a tripod-shape constant-velocity universal joint using a tripod member formed by using such a closed forging die.;SOLUTION: The closed forging die includes openable and closable dies 11, 12 and punches 14, 15 for pressing a material in the dies 11, 12. Using the closed forging die, a product (a tripod member) 16 having bosses 18 and shafts 17, which are radially projected from the bosses 18, is formed. The area of projection of the bosses 18, which is projected onto the side of the dies 11, 12 in the direction of the boss axes, is made smaller than the area of projection of the bosses with outer diameter surfaces made convex having the boss axes as centers, which projection is projected onto the side of the dies in the direction of the boss axes.;COPYRIGHT: (C)2010,JPO&INPIT