| 摘要 |
PURPOSE:To form a crank shaft efficiently up to final finishing stage using a pair of dies by enclosing with pressure a shaftlike material in a pair of dies and pressing in punches in stages to the journal shaft part and position of pin shaft. CONSTITUTION:A billet A having the length of a crank shaft is set in dies 1, 1' and clamped, and the billet A is held in the hollow. A punch 8 for forming the journal shaft passed through opposite to molds 1, 1' is pressed into the billet A to form a journal shaft. Then, excess metal of the billet A is moved to an adjacent space for forming the crank throw part. When a punch 9 for forming the crank throw part is pressed into the excess metal part, the excess metal enters the crank throw part (c) between the punch 8 and a recessed part 4 for forming the pin shaft of another die 1 and extruded to fill the balance weight part (d). By this way, a solid type crank shaft is formed finally. |
