HYDRAULSYSTEM INNEFATTANDE EN DEPLACEMENTVARIABEL PUMP

摘要

A pump control system characterized in that the pressure drop across a variable area orifice embodied in a directional control valve for a fluid motor is utilized to vary the displacement of the pump so that the fluid motor is actuated at desired speed irrespective of variation of pump speed and motor load. The system is further characterized in that it embodies a power limiting device which senses increasing motor load pressure to decrease the displacement of the pump as the horsepower requirement approaches the maximum available horsepower. Yet a further characterizing feature of the present system is the provision of a pump de-stroking valve which is disposed in the pump output circuit upstream of the directional control valve to provide a bypass to the reservoir to maintain standby power drain at a low value.