Title:
HYDRAULIC SYSTEM FOR OPERATING MACHINE
Document Type and Number:
WIPO Patent Application WO/2011/046184
Kind Code:
A1
Abstract:
Provided is a hydraulic system for an operating machine, which can prevent deterioration of fuel efficiency by reducing energy loss and obtain good very low-speed operability when heavy-load very low-speed operation work is performed using a hydraulic cylinder as a hydraulic actuator.
A center bypass cut valve (41) is disposed on the most downstream side of a center bypass line (26), and control is performed in such a manner that the center bypass cut valve (41) is activated by pressure sensors (42, 43), a controller (44) and an electromagnetic valve (45) when an operation means (16) corresponding to a boom cylinder (5) (a specific hydraulic actuator) among a plurality of operation means (18-21) is operated such that pressure oil is supplied to a cylinder chamber (5a) on the load holding side of the boom cylinder (5), and that the discharge pressure of a first hydraulic pump (2) becomes higher than the load pressure of the boom cylinder (5).
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Inventors:
KODAKA Katsuaki (Tsuchiura Works, Intellectual Property Department, 650, Kandatsumachi, Tsuchiura-sh, Ibaraki 13, 〒3000013, JP)
小高 克明 (〒13 茨城県土浦市神立町６５０番地 日立建機株式会社土浦工場 知的財産部内 Ibaraki, 〒3000013, JP)
NAKAMURA Yuta (Tsuchiura Works, Intellectual Property Department, 650, Kandatsumachi, Tsuchiura-sh, Ibaraki 13, 〒3000013, JP)
小高 克明 (〒13 茨城県土浦市神立町６５０番地 日立建機株式会社土浦工場 知的財産部内 Ibaraki, 〒3000013, JP)
NAKAMURA Yuta (Tsuchiura Works, Intellectual Property Department, 650, Kandatsumachi, Tsuchiura-sh, Ibaraki 13, 〒3000013, JP)
Application Number:
JP2010/068082
Publication Date:
April 21, 2011
Filing Date:
October 14, 2010
Export Citation:
Assignee:
HITACHI CONSTRUCTION MACHINERY CO., LTD. (5-1 Koraku 2-chome, Bunkyo-ku Tokyo, 63, 〒1128563, JP)
日立建機株式会社 (〒63 東京都文京区後楽二丁目５番１号 Tokyo, 〒1128563, JP)
KODAKA Katsuaki (Tsuchiura Works, Intellectual Property Department, 650, Kandatsumachi, Tsuchiura-sh, Ibaraki 13, 〒3000013, JP)
小高 克明 (〒13 茨城県土浦市神立町６５０番地 日立建機株式会社土浦工場 知的財産部内 Ibaraki, 〒3000013, JP)
日立建機株式会社 (〒63 東京都文京区後楽二丁目５番１号 Tokyo, 〒1128563, JP)
KODAKA Katsuaki (Tsuchiura Works, Intellectual Property Department, 650, Kandatsumachi, Tsuchiura-sh, Ibaraki 13, 〒3000013, JP)
小高 克明 (〒13 茨城県土浦市神立町６５０番地 日立建機株式会社土浦工場 知的財産部内 Ibaraki, 〒3000013, JP)
International Classes:
F15B11/00; E02F9/22
Attorney, Agent or Firm:
KASUGA Yuzuru (Torii-nihonbashi Bldg, 4-1 Nihonbashi-honcho 3-chome, Chuo-k, Tokyo 23, 〒1030023, JP)
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