| 摘要 |
PROBLEM TO BE SOLVED: To improve the productivity in cold forging of a hollow shaft having a flange-like flange part on one end side in an axial direction and a stepped part with an outer diameter dimension changing stepwise toward the other end in the axial direction.SOLUTION: After execution of a first motion where a ram 4 is moved to a first preset position to press a work-piece held by a die 6 under a punch 9, a movement direction of the ram 4 is reversed, and a change motion is executed where a position of the punch 9 is changed as the work-piece remains held by the die 6. Thereafter, the ram 4 is moved to a second position set closer to the die 6 than to the first position, thereby executing the second motion again where the work-piece is pressed under the punch 9. |
