초록 ▼

A variable displacement piston pump of the type in which the hydraulic pressure in a pressure chamber of an output flow variable element is controlled by a proportional electro-hydraulic control valve to control the displacement of the variable element against a spring to vary the output flow within

A variable displacement piston pump of the type in which the hydraulic pressure in a pressure chamber of an output flow variable element is controlled by a proportional electro-hydraulic control valve to control the displacement of the variable element against a spring to vary the output flow within a range between a maximum output flow and a full cut-off and the output pressure or both the output pressure and the output flow of the pump are controlled electro-hydraulically through a closed loop. The variable displacement piston pump includes flow detector for generating an electric signal corresponding to the output flow of the pump, pressure detector for generating an electric signal corresponding to the output flow of the pump, and control amplifier responsive to the difference between a flow setting signal and the output signal of the flow detector to control a driving control current supplied to the proportional electro-hydraulic control valve and also responsive to the detected output pressure reaching a predetermined value to control the driving control signal in accordance with the difference between a pressure setting signal and the output signal of the pressure detector.

대표청구항 ▼

A variable displacement piston pump of a type which varies an output flow by controlling a hydraulic pressure to displace a variable element against a spring force, said pump comprising: pressure detecting means for generating an electric signal output corresponding to a pump output pressure; a prop

A variable displacement piston pump of a type which varies an output flow by controlling a hydraulic pressure to displace a variable element against a spring force, said pump comprising: pressure detecting means for generating an electric signal output corresponding to a pump output pressure; a proportional electro-hydraulic control valve means for communicating a pressure chamber of the variable element with a tank or a pump outlet port with an opening proportional to an input current; and control amplifier means for receiving an externally applied pressure setting signal and the electric output signal from said pressure detecting means to control the input signal to said proportional elector-hydraulic control valve means in such a manner that said output pressure is introduced into the pressure chamber of said variable element to cut off said pump when a pressure detected by said pressure detecting means attains a setting pressure value, said variable element being connected to flow detecting means for detecting a pump output flow in accordance with the displacement of said variable element, and said control amplifier means including a control circuit responsive to a difference between an externally applied flow setting signal and a flow detection signal from said flow detecting means to adjust the magnitude of said input current.