# US 10,871,176 B2 · Fluid pressure control device

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- Number: US 10,871,176 B2
- Document ID: US10871176B2
- Status: Granted
- Kind: B2
- Application number: 16/633,332
- Filed: 2019-02-27
- Published: 2020-05-21
- Granted: 2020-12-22
- Earliest claimed: 2018-04-27
- Assignees: KYB Corporation
- Applicants: KYB Corporation
- Inventors: Keiichi Matsuzaki; Shunsuke Fukuda
- Web page: https://patentgrep.com/patent/US10871176B2

## CPC

- F15B 11/162: {for giving priority to particular servomotors or users}
- E02F 9/2232: {using one or more variable displacement pumps}
- E02F 9/2285: {Pilot-operated systems}
- E02F 9/2292: {Systems with two or more pumps}
- E02F 9/2296: {Systems with a variable displacement pump}
- F15B 11/17: using two or more pumps
- F15B 2211/20576: with multiple pumps
- F15B 2211/3111: the pump port being closed in the centre position, e.g. so-called closed centre
- F15B 2211/329: actuated by fluid pressure
- F15B 2211/355: Pilot pressure control
- F15B 2211/411: the positions being discrete
- F15B 2211/41509: being connected to a pressure source and a directional control valve
- F15B 2211/428: actuated by fluid pressure
- F15B 2211/50536: using unloading valves controlling the supply pressure by diverting fluid to the return line
- F15B 2211/528: actuated by fluid pressure
- F15B 2211/575: Pilot pressure control
- F15B 2211/6355: having valve means
- F15B 2211/7058: Rotary output members
- F15B 2211/7135: Combinations of output members of different types, e.g. single-acting cylinders with rotary motors
- F15B 2211/7142: the output members being arranged in multiple groups
- F15B 2211/781: one or more output members having priority
- F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- E02F: DREDGING; SOIL-SHIFTING (winning peat E21C49/00)

## Abstract

A fluid pressure control device includes a first switching valve provided on a downstream of a first travel control valve in the first main passage and having an open position and a priority position, a second switching valve provided on a downstream of a second travel control valve in the second main passage and having an open position and a priority position, and a merging passage connecting a downstream of the first switching valve and a downstream of the second switching valve. In a state where first work control valves and second work control valves are not operated and the first travel control valve is operated, the first switching valve is at a priority position, and in a state where the first work control valves and the second work control valves are not operated and the second travel control valves is operated, the second switching valve is at a priority position.

## Claims

### Claim 1

A fluid pressure control device, comprising:
a first main passage to which a working fluid is supplied from a first pump port;
a second main passage to which the working fluid is supplied from a second pump port;
a plurality of first work control valves for work devices connected to the first main passage in parallel;
a plurality of second work control valves for work devices connected to the second main passage in parallel;
a first travel control valve for a travel device connected to the first main passage in parallel at an upstream of the first work control valves;
a second travel control valve for a travel device connected to the second main passage in parallel at an upstream of the second work control valves;
a first switching valve provided on a downstream of a connection portion with the first travel control valve in the first main passage and having an open position where the first main passage is opened and a first priority position where the working fluid from the first pump port is led to the first travel control valve with priority;
a second switching valve provided on a downstream of a connection portion with the second travel control valve in the second main passage and having an open position where the second main passage is opened and a first priority position where the working fluid from the second pump port is led to the second travel control valve with priority; and
a merging passage connecting a downstream of the first switching valve in the first main passage and a downstream of the second switching valve in the second main passage, wherein
in a state where the first work control valves and the second work control valves are not operated and the first travel control valve is operated, the first switching valve is at the first priority position; and
in a state where the first work control valves and the second work control valves are not operated and the second travel control valves is operated, the second switching valve is at the first priority position.

### Claim 2 (depends on 1)

The fluid pressure control device according to claim 1, wherein
in a state where at least one of a plurality of the first work control valves and a plurality of the second work control valves is operated, the first switching valve and the second switching valve are at the open position.

### Claim 3 (depends on 1)

The fluid pressure control device according to claim 1, wherein
at least one of the plurality of the first work control valves is a priority control valve provided on an upstream of the first switching valve and in parallel with the first travel control valve; and
in a state where the first travel control valve and the second travel control valve are not operated and the priority control valve is operated, the first switching valve is at the first priority position.

### Claim 4 (depends on 1)

The fluid pressure control device according to claim 1, wherein
at least one of the plurality of the first work control valves is a priority control valve provided on an upstream of the first switching valve and in parallel with the first travel control valve;
the first switching valve further has a second priority position where the working fluid from the first pump port is led to the priority control valve with more priority than the other first work control valves; and
in a state where the first travel control valve and the second travel control valve are not operated and the priority control valve is operated, the first switching valve is at the second priority position.

### Claim 5 (depends on 3)

The fluid pressure control device according to claim 3, wherein
in a state where the first travel control valve and the priority control valve are operated, the first switching valve is at the open position.

### Claim 6 (depends on 4)

The fluid pressure control device according to claim 4, wherein
the first switching valve blocks a flow of the working fluid at the first priority position, and has a throttle applying resistance to the flow of the working fluid at the second priority position.

### Claim 7 (depends on 4)

The fluid pressure control device according to claim 4, wherein
in a state where the first travel control valve and the priority control valve are operated, the first switching valve is at the open position.