| 摘要 |
PROBLEM TO BE SOLVED: To provide a compactly constituted die cushion device having a blank holding function and floating-up preventing function. SOLUTION: A cylinder 21 used in common with pressurizing and locking which is connected to a pressure pad is provided, and the piston pressure receiving area of the upper oil chamber 25a of the cylinder 21 used in common with pressurizing and locking is set to be larger than that of the lower oil chamber 25b. When a die is lowered, the discharging quantity of a residual pressure oil at a time of oil flowing into the upper oil chamber 25a from the lower oil chamber 25b is controlled by a discharge control servo valve SV1, and whereby the cylinder 21 used in common with pressurizing and locking is controlled to execute blank holding. Also, when the die is raised, a supplying logic valve R1 and a switching logic valve R2 are closed, and the cylinder 21 used in common with pressurizing and locking is locked. Further, the discharging quantity of the residual pressure oil flowing into the lower oil chamber 25b from the upper oil chamber 25a when the die is raised is controlled by the discharge control servo valve SV1 to control a raising speed of a pressure ring.
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