MOLD FOR FORGING HOLLOW STEPPED-PIN AND METHOD FOR FORGING HOLLOW STEPPED-PIN

摘要

PROBLEM TO BE SOLVED: To form a hollow stepped-pin forged of metal plate, which further improves the freedom of design.;SOLUTION: The hollow multiply stepped-pin SP is formed by pressing down a metal plate 2 arranged below a stripper plate 12 from the above to eject the pin SP downwardly from the plate 2, whose internal and external diameters become smaller toward the leading end. The mold includes a first-step punch 14 which forms a first step SP1 and a second-step punch 16 whose internal and external diameters are smaller than those of the SP1 and which forms a second step SP2 downwardly protruding from the SP1. The diameter of a second-step pressing punching part 16c of the punch 16, which is inserted in a second through-hole 12b of the second-step punch 16, is formed to be the same as the internal diameter of the SP2. The through-hole 12b is formed to face to the position at which the lower end surface of the punching part 16c forms the SP2 out of the upper surface of the first-step SP1.;COPYRIGHT: (C)2012,JPO&INPIT