Hydraulic system of work machine and work machine

Patent metadata

Field	Value
Publication number	US-2021102626-A1
Application number	US-202017124492-A
Country	US
Kind code	A1
Filing date	Dec 17, 2020
Priority date	Dec 7, 2015
Publication date	Apr 8, 2021
Grant date	—

Abstract

A hydraulic system of a work machine includes a first hydraulic device to operate in a first operation mode while pressure of hydraulic oil supplied from a hydraulic pump via a first oil passage is equal to or higher than a first pressure threshold. The hydraulic oil in the first oil passage is to be discharged via a second oil passage. A pilot check valve is provided in the second oil passage and has a pilot port to receive a pilot pressure of the hydraulic oil. The pilot check valve is closed to stop discharging the hydraulic oil in the first oil passage through the second oil passage while the pilot pressure is lower than the fourth pressure threshold. The pilot check valve is opened while the pilot pressure is higher than or equal to the fourth pressure threshold. The first hydraulic device is a ride control device.

First claim

What is claimed is:

1 . A hydraulic system of a work machine, comprising:
a hydraulic pump to discharge hydraulic oil; a first hydraulic device to operate in a first operation mode while pressure of the hydraulic oil supplied from the hydraulic oil is equal to or higher than a first pressure threshold; a first oil passage which connects the first hydraulic device and the hydraulic pump and via which the hydraulic oil is to be supplied to the first hydraulic device from the hydraulic pump; a second oil passage which is connected to the first oil passage and via which the hydraulic oil in the first oil passage is to be discharged; a pilot check valve provided in the second oil passage and having a pilot port to receive a pilot pressure of hydraulic oil, the pilot pressure being controlled to be a pressure lower than a fourth pressure threshold when an operation mode of the first hydraulic device is changed to the first operation mode, the pilot check valve being closed to stop discharging the hydraulic oil in the first oil passage through the second oil passage while the pilot pressure is lower than the fourth pressure threshold, the pilot valve being opened such that the hydraulic oil in the first oil passage is discharged through the second oil passage while the pilot pressure is higher than or equal to the fourth pressure threshold; a third oil passage connected to the pilot port; a first actuator to control an amount of hydraulic oil flowing to the third oil passage; a hydraulic actuator; and an operation control valve to control an operation of the hydraulic actuator, wherein the first hydraulic device is a ride control device to perform a vibration control operation to suppress a pressure fluctuation of the hydraulic actuator in accordance with the pressure of the hydraulic oil, and wherein the first actuator is a remote control valve connected to the operation control valve to control the pressure of the hydraulic oil in accordance with an operation of an operating member.

2 . A work machine comprising a hydraulic system according to claim 1 .

Assignees

• Kubota Kk

Inventors

• Fukuda Yuji
• Arii Kazuyoshi
• Sumiyoshi Ryohei

Classifications

• F15B2211/3058

  having additional valves for interconnecting the fluid chambers of a double-acting actuator, e.g. for regeneration mode or for floating mode · CPC title

• B60K17/10

  of fluid gearing · CPC title

• F15B2211/30525

  Directional control valves, e.g. 4/3-directional control valve · CPC title

• F15B2211/7058

  Rotary output members · CPC title

• F15B2211/355

  Pilot pressure control · CPC title