| 摘要 |
PCT No. PCT/JP94/01213 Sec. 371 Date Mar. 15, 1995 Sec. 102(e) Date Mar. 15, 1995 PCT Filed Jul. 22, 1994 PCT Pub. No. WO95/04227 PCT Pub. Date Feb. 9, 1995A hydraulic device for operating an actuator in a working machine such as a hydraulic shovel or the like has a solenoid-operated proportional flow regulating valve connected to a pipe between a hydraulic pump and a directional control valve for changing the direction in which the actuator operates, and a discharge pressure control assembly for controlling the discharge pressure from the hydraulic pump to make constant the differential pressure between the inlet and outlet ports of the solenoid-operated proportional flow regulating valve. Flow rate characteristics of oil supplied under pressure to the actuator with respect to the amount of controlling movement of a control lever are established by a flow rate setting unit depending on a load pressure on the actuator and the rotational speed of an engine which operates the hydraulic pump. The opening of the solenoid-operated proportional flow regulating valve is controlled by a solenoid-operated valve control unit depending on the amount of controlling movement of the control lever in accordance with the established flow rate characteristics. It is possible to obtain suitable flow rate characteristics of oil supplied under pressure to the actuator to meet the operator's preference or various working patterns, and the operator can quickly and easily recognize the load condition of the actuator through the operation of the control lever.
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