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Patent Searching and Data


Title:
HYDRAULIC DRIVE DEVICE FOR WORK MACHINE
Document Type and Number:
WIPO Patent Application WO/2018/168236
Kind Code:
A1
Abstract:
Provided is a hydraulic drive device for a work machine that stores energy in a pressure accumulator and thereby recovers/reuses the energy, wherein operability corresponding to a change in the load on a front work machine due to the cargo or the like can be maintained when an operation to lower the front work machine is carried out. This hydraulic drive device 5, which is equipped with a main pump 101, a boom cylinder 3, a tank 20, a flow rate control valve 6, and an accumulator 300, also has a first differential pressure control valve 201, which is arranged between the boom cylinder 3 and the accumulator 300, and which controls discharge oil from the boom cylinder 3 such that the differential pressure across the flow rate control valve 6 reaches a target differential pressure, and a second differential pressure control valve 202, which is arranged between the accumulator 300 and the tank 200, and which controls the discharge oil such that the differential pressure between the upstream pressure and the downstream pressure of both the flow rate control valve 6 and the first differential pressure control valve 201 reaches a target differential pressure. The first and second differential pressure control valves 201 and 202 are configured such that the target differential pressure increases in correspondence with an increase in the pressure of the discharge oil.

Inventors:
ITO Masamichi (Hitachi Construction Machinery Co. Ltd., 650, Kandatsumachi, Tsuchiura-sh, Ibaraki 13, 〒3000013, JP)
OOKI Takatoshi (Hitachi Construction Machinery Co. Ltd., 650, Kandatsumachi, Tsuchiura-sh, Ibaraki 13, 〒3000013, JP)
Application Number:
JP2018/003313
Publication Date:
September 20, 2018
Filing Date:
January 31, 2018
Export Citation:
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Assignee:
HITACHI CONSTRUCTION MACHINERY CO., LTD. (16-1, Higashiueno 2-chome Taito-k, Tokyo 15, 〒1100015, JP)
International Classes:
F15B21/14; E02F9/22; F15B11/05
Foreign References:
JP2016035321A2016-03-17
JP2017020544A2017-01-26
Attorney, Agent or Firm:
THE PATENT BODY CORPORATE TAKEWA INTERNATIONAL PATENT OFFICE (UNIZO Nishishimbashi 3-chome Bldg, 13-3 Nishishimbashi 3-chome, Minato-k, Tokyo 03, 〒1050003, JP)
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