Title:
HYDRAULIC DRIVE DEVICE FOR HYDRAULIC WORKING MACHINE
Document Type and Number:
WIPO Patent Application WO/2011/027791
Kind Code:
A1
Abstract:
Provided is a hydraulic drive device for a hydraulic working machine by which a jack-up operation can be realized without providing a center by-pass change-over valve and a flow control valve enabling supplying of a pressurized oil to a direction control valve for a working element. The hydraulic drive device for a hydraulic working machine is provided with: a first hydraulic pump (21) and a second hydraulic pump (22); a first boom direction control valve (28) and a second boom direction control valve (29) for controlling a boom cylinder (9); and a third boom direction control valve (30) for controlling the boom cylinder (9) and a third hydraulic pump (23) for supplying a pressurized oil to the third boom direction control valve (30). The jack-up change-over valve (31) has a second change-over position (31b) in which when the pressure in a bottom chamber (9a) of the boom cylinder (9) is below a predetermined pressure, the pressurized oil discharged from the second hydraulic pump (22) and the third hydraulic pump (23) can be supplied to a rod chamber (9b) of the boom cylinder (9) in accordance with the change-over of the second boom direction control valve (29) and the third boom direction control valve (30) by the operation of an operation device (32).
Inventors:
OKANO YASUO (JP)
NAKAMURA TSUYOSHI (JP)
ISHIKAWA KOUJI (JP)
SATO KENSUKE (JP)
HAGIWARA NAOKI (JP)
NAKAMURA TSUYOSHI (JP)
ISHIKAWA KOUJI (JP)
SATO KENSUKE (JP)
HAGIWARA NAOKI (JP)
Application Number:
PCT/JP2010/064951
Publication Date:
March 10, 2011
Filing Date:
September 01, 2010
Export Citation:
Assignee:
HITACHI CONSTRUCTION MACHINERY (JP)
OKANO YASUO (JP)
NAKAMURA TSUYOSHI (JP)
ISHIKAWA KOUJI (JP)
SATO KENSUKE (JP)
HAGIWARA NAOKI (JP)
OKANO YASUO (JP)
NAKAMURA TSUYOSHI (JP)
ISHIKAWA KOUJI (JP)
SATO KENSUKE (JP)
HAGIWARA NAOKI (JP)
International Classes:
F15B11/02; E02F9/22; F15B11/024; F15B11/08; F15B11/17
Foreign References:
| JPH062344A | 1994-01-11 | |||
| JPS61116102A | 1986-06-03 | |||
| JPH02136432A | 1990-05-25 | |||
| JP2002115274A | 2002-04-19 | |||
| JP2002181004A | 2002-06-26 | |||
| JP2008185099A | 2008-08-14 |
Other References:
None
Attorney, Agent or Firm:
The Patent Body Corporate TAKEWA INTERNATIONAL PATENT OFFICE (JP)
Patent business corporation Takekazu international patent firm (JP)
Patent business corporation Takekazu international patent firm (JP)
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