| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a molded article, on both ends in the axial direction of which a first upsetting molded part and a second upsetting molded part are formed and which has an undercut part between the first and second upsetting molded parts. SOLUTION: First upsetting is executed in which an upper annular sidewall part 20 is plastically deformed outward in the radial direction by the first molding section 92 of a punch 90, thereby forming a first upsetting molded part 26a on one end. Subsequently, second upsetting is executed in which a lower annular sidewall part 22 is pressed by the punch 90 and the lower annular sidewall part 22 is plastically deformed outward in the radial direction, while a split mold 68 descends. Thus, the plastically deformed parts flow into and fill the second molding section 82 of the split mold 68 to form a second upsetting molded part 26b on the other end in the axial direction. Simultaneously, the undercut part is formed between the first upsetting molded part 26a and the second upsetting molded part 26b by an undercut molding section 80 of the split mold 68. COPYRIGHT: (C)2008,JPO&INPIT
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