| 摘要 |
PURPOSE:To prevent a trouble such as seizure of dies, breakdown of a punch, etc., by piercing a through-hole on a projecting part of a rough cylindrical body formed by composite extrusion, and subsequently, further extruding said projecting part forward, and extending it. CONSTITUTION:A material M is set to a fixed position in dies 11, a punch 2 is made to go down from the upper part, simultaneously a ram 32 is made to go up from an ejector 31, and a rough cylindrical body M4 on which a projecting part C has been formed by means of composite extrusion is pressed and molded. Subsequently, a punch 2c being somewhat thick is made to go down to the rough cylindrical body M4, and an intermediate rough cylindrical body M5 which has pierced a through-hole B is pressed and molded. Subsequently, the intermediate rough cylindrical body M5 is taken out from the dies 11 by making the ejector 31 go up, is inserted into dies 12 for molding a finished cylindrical body, which has been prepared separately, the punch 2 which has projected a stepped snap 2a is made to go down, and a finished cylindrical body M6 which has extended said projecting part C by extruding it forward is pressed and molded. In this case, the outside circumferential surface of an extended projecting part D is tapered E. |
