Patent attributes
A circuit for controlling a discharge amount of a hydraulic pump to an actuator irrespective of a load pressure of the actuator even when an engine operates at a low speed has a variable displacement hydraulic pump connected with the engine; an actuator connected with the hydraulic pump; a center-bypass directional switching valve in a flow path between the hydraulic pump and the actuator for controlling start, stop and directional switching of the actuator during a switching operation; a pilot signal generating means in a down stream side of the center bypass for controlling the discharge amount of the hydraulic pump; and a discharge amount adjusting valve in a supply path of the actuator of the directional switching valve for controlling a discharge amount of hydraulic fluid to the actuator.
