MANUFACTURING METHOD OF OUTSIDE JOINT MEMBER FOR CONSTANT VELOCITY UNIVERSAL JOINT, INTERMEDIATE FORGED PRODUCT PROCESSED TO OUTSIDE JOINT MEMBER, AND FINAL FORGED PRODUCT

摘要

PROBLEM TO BE SOLVED: To manufacture a high-quality outside joint member at a low cost.;SOLUTION: A manufacturing method of an outside joint member 1 includes: a pre-forging step for molding a rod-shaped raw material M into an intermediate forged product 21 having a cup-shaped part 22 in which track grooves are roughly formed at an inside diameter face after sequentially molding the rod-shaped raw material M into first to third middle products M1 to M3 by performing, for example, four times of forging processing stepwise; and a grueling step for molding the intermediate forged product into a final forged product having track grooves 5 of finished shapes. The third middle product M3 manufactured in the pre-forging step has, at its one end face M3a, an endless third mark M3b formed by the deformation of the rod-shaped raw material M to a one-end external edge Mb, and the third mark M3b is wholly arranged outside in a radial direction rather than a pressurized region of the one end face M3a formed by a molding punch 32 of the cup-shaped part 22.;COPYRIGHT: (C)2015,JPO&INPIT