| 摘要 |
<p>A control system for a load-sensing hydraulic drive circuit comprising; at least one hydraulic pump (1); a plurality of hydraulic actuators (2,3) driven with hydraulic fluid delivered from the hydraulic pump; and a pressure compensated flow control valve (4,5,6,7) connected between the pump and each of the actuators, for controlling a flow rate of the fluid supplied to each the actuator in response to an operation signal from control means. The control system comprises first detection means (43) for detecting a differential pressure ( DELTA P) between the delivery pressure of the pump and the maximum load pressure among the plurality of hydraulic actuators; second detection means (14) for detecting the delivery pressure of the pump; first means for calculating, based on a differential pressure signal from the first detection means, a differential pressure target delivery amount Q DELTA p of the pump to hold the differential pressure constant; second means for calculating an input limiting target delivery amount QT of the pump based on at least a pressure signal from the second detection means and an input limiting function preset for the pump; third means for selecting one of the differential pressure target delivery amount Q DELTA p and the input limiting target delivery amount QT as a delivery amount target value Qo for the pump, and then controlling the delivery amount of the pump such that it does not exceed above the input limiting target delivery amount QT; and fourth means for calculating a compensation value Qns to limit a total consumable flow rate for the actuator based on at least the input limiting target delivery amount QT and the differential pressure target delivery amount Q DELTA p when the input limiting target delivery amount QT is selected by the third means, and then controlling the pressure compensated flow control valve based on the compensation value Qns.</p> |
