HYDRAULIC CIRCUIT FOR CONSTRUCTION MACHINE, AND HYDRAULIC CIRCUIT

Title:

HYDRAULIC CIRCUIT FOR CONSTRUCTION MACHINE, AND HYDRAULIC CIRCUIT

Document Type and Number:

WIPO Patent Application WO/2020/189352

Kind Code:

A1

Abstract:

Provided is a hydraulic circuit, for a construction machine, which drives an actuator by merging pressure oil from a fixed-volume pump into a center bypass oil path from a variable-volume pump to an oil tank, wherein the flow rate of flow from the fixed-volume pump to the center bypass oil path can be controlled in accordance with a requested flow rate of the actuator.　A distribution direction-switching valve 64, which has a first oil path 64a from a fixed-volume pump 62 to an oil tank T and a second oil path 64b from the fixed-volume pump 62 to a first center bypass oil path 61c, has a first signal reception unit 641 which causes a spool to slide in a direction in which the first oil path 64a is formed, and a second signal reception unit 642 which causes a spool to slide in a direction in which the second oil path 64b is formed, and determines a distribution ratio of pressure oil flowing to the first oil path 64a and the second oil path 64b in accordance with the difference in size of the signals received by the first signal reception unit 641 and the second signal reception unit 642, the first signal reception unit 641 receiving a signal based on a negative control signal.

Inventors:

ONO JUNYA (JP)
MATSUYAMA HIROSHI (JP)
KAGEYAMA NAOTO (JP)
IWASAKI HITOSHI (JP)
TUKAHARA NANAMI (JP)

Application Number:

PCT/JP2020/009846

Publication Date:

September 24, 2020

Filing Date:

March 06, 2020

Export Citation:

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Assignee:

YANMAR CO LTD (JP)
NABTESCO CORP (JP)

International Classes:

F15B11/16; E02F9/22; F15B11/00; F15B11/17

Domestic Patent References:

WO2009123047A1

2009-10-08

Foreign References:

JPS5616735A	1981-02-18
JP2014015903A	2014-01-30
JP2012112466A	2012-06-14

Other References: