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:
Jan. 22, 2019

Filed:

Mar. 02, 2017
Applicant:

Hitachi Construction Machinery Co., Ltd., Taito-ku, Tokyo, JP;

Inventors:

Masamichi Ito, Ushiku, JP;

Takatoshi Ooki, Kasumigaura, JP;

Kiwamu Takahashi, Moriyama, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F15B 21/14 (2006.01); E02F 9/22 (2006.01); F15B 1/04 (2006.01); F15B 11/08 (2006.01); F15B 13/02 (2006.01); F15B 13/04 (2006.01); F15B 11/024 (2006.01); E02F 3/32 (2006.01);
U.S. Cl.
CPC ...
E02F 9/2225 (2013.01); E02F 9/22 (2013.01); E02F 9/2217 (2013.01); E02F 9/2232 (2013.01); E02F 9/2267 (2013.01); E02F 9/2271 (2013.01); E02F 9/2285 (2013.01); E02F 9/2296 (2013.01); F15B 1/04 (2013.01); F15B 11/024 (2013.01); F15B 11/08 (2013.01); F15B 13/026 (2013.01); F15B 13/0401 (2013.01); F15B 21/14 (2013.01); E02F 3/32 (2013.01); F15B 2211/40561 (2013.01); F15B 2211/40569 (2013.01); F15B 2211/465 (2013.01); F15B 2211/57 (2013.01); F15B 2211/88 (2013.01);
Abstract

To keep operability of a hydraulic actuator excellent even in a state pressure has been sufficiently accumulated in a pressure accumulator. In a hydraulic driving device of a work machine including a hydraulic actuator, a tank, a flow control valve, and a pressure accumulator, there are further provided with a first pressure compensation valve that is for controlling difference between front and back pressures of the flow control valve constant and a second pressure compensation valve that is arranged between the pressure accumulator and the tank and is for controlling difference between front and back pressures of the flow control valve and the first pressure compensation valve constant.


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