To provide a double acting hydraulic press with which the operation of a plurality of cylinders reduces the consumption of an operating oil by controlling both uses of rotation control of a hydraulic pump and a control servo-valve in a power unit.
In the double acting hydraulic press having a main cylinder 30 for acting a slide 2 and a lower forming cylinder 27 for operating a lower forming apparatus 12, control servo-valves 34, 37 for controlling with servo-controllers 41a, 41b are interposed in each hydraulic circuit from the power unit composed of a variable volume type hydraulic pump driven with an inverter motor 51 to the main cylinder and the lower forming cylinder. Then, cylinder pressure detecting sensors 39a, 39d are arranged in each hydraulic circuit, and positional detecting sensors 40a, 40b for detecting respective positions of the slide and the lower forming apparatus, are arranged and a control unit 32 for inputting a control signal into the power unit and each servo-controller, is arranged and the respective detected values of each cylinder pressure detecting sensor and the positional detecting sensor, are inputted into the above control unit as feedback values.
KAZAMA TAKESHI
KUBOTA IRON WORKS CO LTD
Yoshiaki Sato
Kunihiko Takahashi
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