| 摘要 |
PROBLEM TO BE SOLVED: To provide a die for upset forging composed of a movable die provided with a die cushion device and fixed die for holding a blank. SOLUTION: In the movable die 1, a punch case 4 fixing the punch 3 and a piston 6 are connected with an upper holder 8 through a hydraulic chamber 7. In the fixed die 2, a trancated conical die 21 having the same angle as tapered angle of guides 22, 23, is formed as four split type and a spring for expanding the split surface is inserted and by expansion of the spring, the split dies are raised and the movable die is lowered, and the punch and the punch case are brought into contact with the upper surfaces of the split dies to push down the split dies. The split dies are shrunk with the guides and the blank S is held with a holding surfaces 21u and the working oil is the hydraulic chamber is returned back from the punch case through the piston and then, the die cushion device for making the lock state of the movable die and the fixed die, is arranged.
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