| 摘要 |
<P>PROBLEM TO BE SOLVED: To forge a connecting rod free from underfill and the like by actively controlling a flow direction of a stock when closed-forging a connecting rod by using dual split molds together with a punch for a large end. <P>SOLUTION: A method for closed-forging a connecting rod includes: restraining a rod-like stock 16 with dual split molds 12 that are configured to approach and separate from each other in a direction perpendicular to a longitudinal direction of the rod-like stock while pressurizing the rod-like stock, to forge a rough shape of the connecting rod 1 including a large end 2, a small end and a connecting rod 4; and upsetting a part equivalent to the large end 2 of the stock 16 by the punch 14 for a large end to upset mold a half-split-like bearing recessed part 5 in the large end 2, wherein the upsetting mold is completed while the half-split-like bearing recessed part 5 is left in an imperfectly recessed shape where the deepest part side of the bearing recessed part 5 defines a flat plane 5a when viewed from the axial direction thereof. <P>COPYRIGHT: (C)2013,JPO&INPIT |
