The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
May. 03, 2016

Filed:

Aug. 13, 2012
Applicants:

Teruo Akiyama, Kokubunji, JP;

Noboru Iida, Chigasaki, JP;

Kenji Oshima, Tokyo, JP;

Kenji Sasano, Hiratsuka, JP;

Inventors:

Teruo Akiyama, Kokubunji, JP;

Noboru Iida, Chigasaki, JP;

Kenji Oshima, Tokyo, JP;

Kenji Sasano, Hiratsuka, JP;

Assignee:

KOMATSU LTD., Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F15B 11/00 (2006.01); E02F 9/20 (2006.01); F15B 11/17 (2006.01); E02F 9/12 (2006.01); E02F 9/22 (2006.01); F15B 11/02 (2006.01); F15B 11/028 (2006.01);
U.S. Cl.
CPC ...
E02F 9/2025 (2013.01); E02F 9/123 (2013.01); E02F 9/2037 (2013.01); E02F 9/2235 (2013.01); E02F 9/2289 (2013.01); E02F 9/2292 (2013.01); E02F 9/2296 (2013.01); F15B 11/02 (2013.01); F15B 11/028 (2013.01); F15B 11/17 (2013.01); F15B 2211/20546 (2013.01); F15B 2211/20561 (2013.01); F15B 2211/20576 (2013.01); F15B 2211/27 (2013.01); F15B 2211/50518 (2013.01); F15B 2211/5159 (2013.01); F15B 2211/526 (2013.01); F15B 2211/6346 (2013.01); F15B 2211/665 (2013.01); F15B 2211/6653 (2013.01); F15B 2211/6654 (2013.01); F15B 2211/7053 (2013.01); F15B 2211/7058 (2013.01); F15B 2211/7135 (2013.01);
Abstract

In a hydraulic excavator, a hydraulic cylinder drives a boom via a hydraulic fluid discharged from a first hydraulic pump. A first hydraulic circuit connects the first hydraulic pump and the hydraulic cylinder and forms a closed circuit therebetween. A hydraulic motor rotates a revolving upper unit with hydraulic fluid discharged from a second hydraulic pump. A second hydraulic circuit independent from the first hydraulic circuit connects the second hydraulic pump and the hydraulic motor. A motor hydraulic pressure reduction unit reduces the driving hydraulic pressure of the hydraulic motor when a predetermined condition is satisfied. The predetermined condition is a condition in which an operation of the boom operating member to raise the boom and an operation of the rotation operating member to rotate the revolving upper unit are conducted together and an operation amount of the boom operating member is equal to or greater than a predetermined threshold.


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