Granted Patent B2

US 12,276,086 · App. 17/499,365 · Granted Apr 15, 2025

Inventor: Yuji Fukuda (Osaka, JP)

Assignee: KUBOTA CORPORATION

E02F9/2217F15B11/024E02F9/2282F15B2211/3116F15B2211/3133F15B2211/40507

Abstract

Claims (82)

1. A hydraulic system for a working machine, comprising:

a hydraulic actuator configured to be operated by operation fluid;

a first control valve connected to the hydraulic actuator;

a second control valve disposed downstream of the first control valve;

a communication fluid line for fluid communication between the hydraulic actuator and the control valve; and

a discharge fluid line to discharge the operation fluid from the first control valve,

wherein the first control valve comprises:

a first input port, a first communication port, a second communication port, an output port, and a discharge port;

a first supply path from the first input port to the second communication port to guide the operation fluid toward the hydraulic actuator;

a regeneration path from the first communication port to the first supply path to guide the operation fluid having been returned to the first control valve from the hydraulic actuator, to the first supply path and not to the discharge fluid line through the discharge port; and

a branched path that branches from the regeneration path and supplies the operation fluid to the second control valve and not to the discharge fluid line, and

wherein the discharge port is disconnected or isolated from the regeneration path and the branched path, to prevent fluid communication from the regeneration path and the branched path to the discharge port, and

wherein the branched path has a first throttle.

2. The hydraulic system for the working machine according to claim 1 , wherein

the first control valve is configured to be switched between a first position at which the hydraulic actuator retracts and a second position at which the hydraulic actuator extends, and

the operation fluid is guided through the first supply path, the regeneration path, and the branched path when the first control valve is at the second position.

3. The hydraulic system for the working machine according to claim 2 , wherein

the branched path is connected to the output port through which the operation fluid flows out, for supplying the operation fluid toward the second control valve disposed downstream of the first control valve.

4. The hydraulic system for the working machine according to claim 1 , wherein

the first control valve further comprises:

a second input port through which the operation fluid flows in; and

a second supply path connected to the second input port,

wherein the branched path is connected with the second supply path.

5. The hydraulic system for the working machine according to claim 1 , wherein a second supply path has a second throttle.

6. The hydraulic system for the working machine according to claim 1 , further comprising a bucket provided on a boom, wherein the hydraulic actuator is a bucket cylinder for actuating the bucket.

7. A hydraulic system for a working machine, comprising:

a hydraulic actuator configured to be operated by operation fluid;

a first control valve connected to the hydraulic actuator;

a second control valve disposed downstream of the first control valve;

first and second communication fluid lines for fluid communication between the hydraulic actuator and the first control valve; and

a discharge fluid line to discharge the operation fluid from the first control valve to an operation fluid tank,

wherein the first control valve comprises:

first and second communication ports connected to the first and second communication fluid lines, respectively:

first and second input ports through which the operation fluid flows in;

an output port through which the operation fluid flows out toward the second control valve;

a discharge port connected to the discharge fluid line;

a first supply path for fluid communication between the first input port and the second communication port;

a regeneration path for fluid communication from the first communication port to the first supply path and not to the discharge port; and

a branched path for fluid communication from the regeneration path to the output port and not to the discharge port, and

wherein the discharge port is disconnected or isolated from the regeneration path and the branched path, to prevent fluid communication from the regeneration path and the branched path to the discharge port, and

wherein the first control valve further comprises a second supply path for fluid communication between the second input port and the output port through the branched path.

8. The hydraulic system for the working machine according to claim 7 , wherein

the first control valve is configured to be switched from a neutral position to a first position for retracting the hydraulic actuator and a second position for extending the hydraulic actuator.

9. The hydraulic system for the working machine according to claim 8 , wherein

the operation fluid is guided from the first input port through the first supply path, the second communication port and the second communication fluid line to the hydraulic actuator, when the first control valve is switched to the second position.

10. The hydraulic system for the working machine according to claim 9 , wherein

the operation fluid is guided from the hydraulic actuator to the first supply path through the first communication port and the regeneration path, when the first control valve is switched to the second position.

11. The hydraulic system for the working machine according to claim 10 , wherein

the operation fluid is guided from the regeneration path to the output port through the branched path, when the first control valve is switched to the second position.

12. The hydraulic system for the working machine according to claim 11 , wherein

the operation fluid is guided from the output port to the second control valve disposed downstream of the first control valve, when the first control valve is switched to the second position.

13. A hydraulic system for a working machine, comprising:

a hydraulic actuator configured to be operated by operation fluid;

a first control valve connected to the hydraulic actuator;

a second control valve disposed downstream of the first control valve;

a communication fluid line for fluid communication between the hydraulic actuator and the control valve; and

a discharge fluid line to discharge the operation fluid from the first control valve,

wherein the first control valve comprises:

a first input port, a first communication port, a second communication port, an output outlet port, and a discharge port;

a first supply path from the first input port to the second communication port to guide the operation fluid toward the hydraulic actuator;

a regeneration path from the first communication port to the first supply path to guide the operation fluid having been returned to the first control valve from the hydraulic actuator, to the first supply path and not to the discharge fluid line through the discharge port; and

a branched path that branches from the regeneration path and supplies the operation fluid to the second control valve and not to the discharge fluid line, and

wherein the discharge port is disconnected or isolated from the regeneration path and the branched path, to prevent fluid communication from the regeneration path and the branched path to the discharge port, wherein

the first control valve is configured to be switched between a first position at which the hydraulic actuator retracts and a second position at which the hydraulic actuator extends, and

the operation fluid having been returned to the first control valve is guided through the first control valve to the discharge fluid line when the first control valve is at the first position.

14. A hydraulic system for a working machine, comprising:

a hydraulic actuator configured to be operated by operation fluid;

a first control valve connected to the hydraulic actuator;

a second control valve disposed downstream of the first control valve;

first and second communication fluid lines for fluid communication between the hydraulic actuator and the first control valve; and

a discharge fluid line to discharge the operation fluid from the first control valve to an operation fluid tank,

wherein the first control valve comprises:

first and second communication ports connected to the first and second communication fluid lines, respectively:

first and second input ports through which the operation fluid flows in;

an output port through which the operation fluid flows out toward the second control valve;

a discharge port connected to the discharge fluid line;

a first supply path for fluid communication between the first input port and the second communication port;

a regeneration path for fluid communication from the first communication port to the first supply path and not to the discharge port; and

a branched path for fluid communication from the regeneration path to the output port and not to the discharge port, and

wherein the discharge port is disconnected or isolated from the regeneration path and the branched path, to prevent fluid communication from the regeneration path and the branched path to the discharge port, wherein

the first control valve is configured to be switched between a first position at which the hydraulic actuator retracts and a second position at which the hydraulic actuator extends, and

the operation fluid having been returned to the first control valve is guided through the second communication port, the discharge port, and the discharge fluid line when the first control valve is at the first position.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (11)