Hydraulic system for working machine

Patent metadata

Field	Value
Publication number	US-10774852-B2
Application number	US-201715854134-A
Country	US
Kind code	B2
Filing date	Dec 26, 2017
Priority date	Dec 28, 2016
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

A hydraulic system for a working machine includes a hydraulic actuator having a first fluid chamber and a second fluid chamber, an accumulator, an outputting fluid tube to output an operation fluid, and a switching valve to be switched between a first position and a second position. The first position allows the first fluid chamber and the second fluid chamber to be communicated with the outputting fluid tube and thereby allowing a floating operation. The second position allows the first fluid chamber and the accumulator to be communicated with each other, allows the second fluid chamber and the outputting fluid tube to be communicated with each other, and thereby allows an anti-vibration operation.

First claim

What is claimed is:

1. A hydraulic system for a working machine, comprising:
a hydraulic actuator having a first fluid chamber and a second fluid chamber;
an accumulator;
a control valve to control the operation fluid that is to be supplied to the hydraulic actuator;
a first supplying tube connecting the control valve to the first fluid chamber;
a second supplying tube connecting the control valve to the second fluid chamber;
a first communicating tube connected to the first supplying tube and connected to the switching valve;
a second communicating tube connected to the second supplying tube and connected to the switching valve;
an outputting fluid tube to output an operation fluid; and
a switching valve to be switched between a first position and a second position,
the first position allowing the first fluid chamber and the second fluid chamber to be communicated with the outputting fluid tube and thereby allowing a floating operation,
the second position allowing the first fluid chamber and the accumulator to be communicated with each other, allowing the second fluid chamber and the outputting fluid tube to be communicated with each other, and thereby allowing an anti-vibration operation,

wherein the switching valve includes a spool to allow the first communicating tube and the outputting fluid tube to communicate with each other and allow the second communicating tube and the outputting fluid tube to communicate with each other when the switching valve is at the first position, and to allow the first communicating tube and the accumulator to communicate with each other and allow the second communicating tube and the outputting fluid tube to communicate with each other when the switching valve is at the second position.

2. The hydraulic system for the working machine according to claim 1 ,
wherein the switching valve includes:
a solenoid valve to which the operation fluid serving as a pilot fluid is supplied; and
a pressure-receiving portion to receive a pressure of the pilot fluid supplied to the solenoid valve,

and wherein the spool includes
an outputting portion to connect the pressure-receiving portion to an outputting port of the switching valve.

3. The hydraulic system for the working machine according to claim 1 ,
wherein the switching valve includes:
a solenoid valve to which the operation fluid serving as a pilot fluid is supplied;
a pressure-receiving portion to receive a pressure of the pilot fluid supplied to the solenoid valve;
an inner fluid tube to connect the solenoid valve to the pressure-receiving portion; and
an outputting fluid tube to output the operation fluid of the inner fluid tube.

4. The hydraulic system for the working machine according to claim 3 ,
wherein the switching valve includes
a spool,

and wherein the pressure-receiving portion includes:
a first pressure-receiving portion arranged on one side of the spool in a longitudinal direction of the spool; and
a second pressure-receiving portion arranged on the other side of the spool in the longitudinal direction,

and wherein the pilot fluid is applied to the first pressure-receiving portion and the second pressure-receiving portion.

5. The hydraulic system for the working machine according to claim 3 , comprising
a control device to control the solenoid valve, the control device being configured to set a pressure to be received by the pressure-receiving portion, the pressure being generated by the pilot fluid,
wherein the control device sets, in warming up of the operation fluid, the pressure to be less than a switching pressure at which the switching valve is switched to the first position or to the second position.

6. The hydraulic system for the working machine according to claim 5 , comprising:
a first switch to issue a first command of the floating operation; and
a second switch to issue a second command of the anti-vibration operation,
wherein the control device is configured to switch the switching valve to the first position or to the second position in accordance with the first command and the second command and to switch the switching valve to the first position when receiving the first command under a state where the switching valve is in the second position in accordance with the second command.

7. The hydraulic system for the working machine according to claim 6 ,
wherein the control device does not switch the switching valve in warming up of the operation fluid regardless of the first command and the second command.

8. The hydraulic system for the working machine according to claim 1 , comprising:
a first switch to issue a first command of the floating operation;
a second switch to issue a second command of the anti-vibration operation; and
a control device to switch the switching valve to the first position or to the second position in accordance with the first command and the second command and to switch the switching valve to the first position when receiving the first command under a state where the switching valve is in the second position in accordance with the second command.

9. A hydraulic system for a working machine, comprising:
a hydraulic actuator having a first fluid chamber and a second fluid chamber;
a control valve to control the operation fluid that is to be supplied to the hydraulic actuator;
a first supplying tube connecting the control valve to the first fluid chamber;
a second supplying tube connecting the control valve to the second fluid chamber;
a first communicating tube connected to the first supplying tube and connected to the switching valve; and
a second communicating tube connected to the second supplying tube and connected to the switching valve;
a first accumulator;
a second accumulator;
an outputting fluid tube to output an operation fluid; and
a switching valve to be switched between a first position and a second position,
the first position allowing the first fluid chamber and the second fluid chamber to be communicated with the outputting fluid tube and thereby allowing a floating operation,
the second position allowing the first fluid chamber and the first accumulator to be communicated with each other, allowing the second fluid chamber and the second accumulator to be communicated with each other, and thereby allowing an anti-vibration operation,

wherein the switching valve includes a spool to allow the first communicating tube and the outputting fluid tube to communicate with each other and allow the second communicating tube and the outputting fluid tube to communicate with each other when the switching valve is at the first position, and to allow the first communicating tube and the first accumulator to communicate with each other and allow the second communicating tube and the second accumulator to communicate with each other when the switching valve is at the second position.

10. The hydraulic system for the working machine according to claim 9 ,
wherein the switching valve includes:
a solenoid valve to which the operation fluid serving as a pilot fluid is supplied;
a pressure-receiving portion to receive a pressure of the pilot fluid supplied to the solenoid valve;
an inner fluid tube to connect the solenoid valve to the pressure-receiving portion; and
an outputting fluid tube to output the operation fluid of the inner fluid tube.

11. The hydraulic system for the working machine according to claim 10 ,
wherein the switching valve includes
a spool,

and wherein the pressure-receiving portion includes:
a first pressure-receiving portion arranged on one side of the spool in a longitudinal direction of the spool; and
a second pressure-receiving portion arranged o

Assignees

• Kubota Kk

Inventors

• Fukuda Yuji
• Honda Keigo
• Kinugawa Ryosuke
• Nishimoto Ryuki
• Yamashita Yuji
• Sakurai Daisuke

Classifications

• E02F9/2203 Primary

  Arrangements for controlling the attitude of actuators, e.g. speed, floating function · CPC title

• F15B2211/635

  Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements · CPC title

• F15B2211/31558

  having a single output member · CPC title

• F15B21/0427

  Heating · CPC title

• E02F9/2207

  for reducing or compensating oscillations · CPC title