| 摘要 |
PURPOSE:To safely and surely execute the press forming necessary for the low pressure output holding like an IC card especially by equipping with an electromagnetic relief valve and a directional control valve respectively on the primary side and secondary side pipe line of a closing cylinder. CONSTITUTION:The set pressure of electromagnetic relief valves 21, 22 are set so as to balance both side pressures based on the piston diameters at the primary and secondary sides of a closing cylinder. The respective position of directional control valves 19, 20 is set to P side and the oil pressure from pumps 15, 16 is fed into ths closing cylinder 3 through pipe lines 17, 18 to make the pressure difference between the primary side and secondary side in zero. Then, the set pressure of the electromagnetic relief valve 21 is devided in relation to the set pressure of the valve 22 so as to generate specific pressure difference in order to enable the operation with the low pressure necessitating the closing output by the ram 3a of the closing cylinder. The oil pressure from the pump 15 is therefore fed into the closing cylinder 3 from an oil port 13 according to the set pressure of the electromagnetic relief valve 21 and the holding of the necessary low pressure output is enabled. |
