| 摘要 |
The invention relates to an arrangement for controlling the die cushion of a die-cushion press. Connected to the pneumatic cylinder of the die cushion on the output side is a hydraulic cylinder, the piston of which is rigidly coupled to the die-cushion piston. During the working stroke of the press, the compressed air is forced out of the pneumatic cylinder without air loss into an air receiver while, during the return stroke, the compressed air is fed in to the pneumatic cylinder in a throttled manner and the hydraulic fluid is withdrawn from the hydraulic cylinder in a throttled manner. The energy conversion is thereby distributed between two throttle valves, excessive heating of the oil thereby being avoided. The two throttle valves can be controlled by a common set point generator and the return speed of the die-cushion piston can thus be varied and, in particular, adapted to different strokes of the press.
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