| 摘要 |
PURPOSE:To improve the working efficiency of a press machine by providing a cylinder and piston which constitute a pressure oil chamber between a upper die and ram, etc. and interposing an accumulator, booster and valve into the hydraulic piping thereof. CONSTITUTION:The cylinder 2 is fixed onto the upper die D2 and the pressure oil chamber 3 is recessed in the central part. The piston 5 having a packing 4 is fitted to the chamber 3 and is attached by a pin 6 so as to form a space (d) between to top surface of the cylinder 2 and the bottom surface of a ram R when the pressure in the chamber 3 attains a set pressure P. A stop valve 11, a check valve 12 and the accumulator 13 are attached to the hydraulic piping 10 connected to the through-hole 8 of the cylinder 2. The accumulator 13 operates when the forming pressure increases in the stage of press forming. The specified pressure in the chamber 3 is thus maintained and the increase of the oil temp. is prevented. Since the fine remote adjustment of the pressure is made possible by a pneumatic cylinder 26, the working efficiency of the press machine is improved.
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