| 摘要 |
PCT No. PCT/EP95/03192 Sec. 371 Date Aug. 8, 1997 Sec. 102(e) Date Aug. 8, 1997 PCT Filed Aug. 11, 1995 PCT Pub. No. WO96/05543 PCT Pub. Date Feb. 22, 1996The present invention relates to a control system for hydraulic power units, in particular hydraulic cylinder-piston-assemblies comprising a valve to be controlled by an electronic controller, the valve controlling the fluid path between the power unit, a pressure source and a reservoir. A pressure sensor and a circuit for differentiating the sensed pressure quantity in response to time is provided for sensing a respective output variable of the power unit. The pressure variation signal is utilized to assist operating the valve to improve the control operation, i.e. to dampen fluid vibrations or to decrease the hammering noise produced in the operation of stamping, nibbling or shearing machines.
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