JPS6189059U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of this invention. The hydraulic control circuit diagrams, Figures 2 to 4 are conceptual diagrams that compare and explain the discharge amount of the pump that constitutes this invention, the opening area of the center bypass passage of the switching valve, and the stroke of the operating stick of the passing flow rate. . 1, 2... pump, 3, 4... regulator,
6, 16, 26... Throttle, 17, 27... Relief valve, 12 to 15 and 22 to 25... Switching valve, 18, 28... Center bypass passage, 34...
... Tank, 40, 41... Control stick.

Claims (1)

[Scope of claim for utility model registration] A pump that increases the discharge amount according to a decrease in pilot pressure, multiple center bypass type switching valves (hereinafter referred to as switching valves), and a pump connected to a tank via a throttle or relief valve. It has two circuits consisting of a pilot pipe branched from the center bypass passage and connected to a regulator that changes the capacity of the pump, and at least one point between the switching valves in one side circuit is connected in tandem. A switching valve in the other side circuit, in which a pipe line on one side of the actuator controlled by the switching valve upstream of the switching valve has a spool that moves synchronously to one side with the spool of the switching valve and does not move to the other side. In a hydraulic circuit connected to an actuator connection port on one side, there is a restriction provided in a pilot pipe connected to a regulator of a pump on one side, and a restriction branched from between the regulator and the regulator to switch the circuit on the other side. A hydraulic control circuit that includes a pilot pipe connected to the actuator connection port on the other side of the valve.