| 摘要 |
PROBLEM TO BE SOLVED: To provide a con'rod manufacturing method capable of obtaining a con'rod having superior symmetric property of cross-sectional shape of a column portion and high buckling strength. SOLUTION: In a hot forging process, the hot forging is performed so that burr 2 is formed on a position offset from a center "a" in the thickness direction of the con'rod 1, and in a trimming process, the con'rod is inserted into a trimming hole of a trimming die at a thicker side from the burr 2, the burr 2 is brought into contact with a burr cutting blade, and the con'rod 1 is pressed to press the burr 2 to the burr cutting blade so that the burr 2 is cut. The offset quantity A from the central position "a" in the thickness direction of the con'rod 1, of the burr 2 preferably satisfies 0<A≤D/4+B/2-C/2 when C<B/4, and B/4≤A≤D/4+B/2-C/2 when C≥B/4 in the relationship with a thickness B of a central portion in the width direction of the column portion 13, a height D of a rib, and a thickness C of the burr 2. COPYRIGHT: (C)2007,JPO&INPIT
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