| 摘要 |
There is a hydraulic control system for a relief valve 16 of an actuating pressure space 13 of a forming machine with a drivable active machine part 2, in which the valve element 17 of the relief valve 16 is subjected at the front side 18 to the pressure of the actuating pressure space 13, in the closed position is pressurised on the rear side 20 and, during the movement of the machine part 2, is opened shortly before the reversal point of the forming stroke, and opens under the pressure of the actuating pressure space 13. It is desirable here if, for the purpose of achieving independence from a pressure rise in the actuating pressure space, the opening of the relief valve at the reversal point is effected in a simplified manner and rapidly by means of the speed of the machine part, without a mass deceleration effect. This is achieved by virtue of the fact that a hydraulic coupling device 21 which, during the forming stroke, outputs an output pressure corresponding to the speed of the machine part 2 up until the reversal point is used and that the pressurisation at the rear side 20 of the valve element 17 is controlled by means of this output pressure. The deceleration of the machine part is compared hydraulically with the previously relatively large speed of the machine part and the signal for the opening of the relief valve is derived hydraulically from this. <IMAGE>
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