Title:
HYDRAULIC DRIVING APPARATUS
Document Type and Number:
WIPO Patent Application WO/2020/110946
Kind Code:
A1
Abstract:
A counter balance valve (71L) is positioned between a directional control valve (23) and a hydraulic motor (32L) and is provided between a pair of supplying/discharging tube paths (25A, 25B). In the counter balance valve (71L), a spool (72L) is displaced in an axial direction on the basis of a pressure difference between the supplying/discharging tube paths (25A, 25B). The counter balance valve (71L) includes a communication path (73L) that communicates the supplying/discharging tube paths (25A, 25B), when displacement of the spool (72L) exceeds a predetermined value (XCM) due to the pressure difference between the supplying/discharging tube paths (25A, 25B). The communication path (73L) is provided in the spool (72L) of the counter balance valve (71L).
Inventors:
ITOH KAZUHIRO (JP)
NUMAGUCHI KAZUHIRO (JP)
NUMAGUCHI KAZUHIRO (JP)
Application Number:
PCT/JP2019/045812
Publication Date:
June 04, 2020
Filing Date:
November 22, 2019
Export Citation:
Assignee:
HITACHI CONSTRUCTION MACH CO (JP)
International Classes:
F15B11/02; E02F9/22
Foreign References:
| JPH08277547A | 1996-10-22 | |||
| JPH08145008A | 1996-06-04 | |||
| JP2014020431A | 2014-02-03 | |||
| JP2005119619A | 2005-05-12 |
Other References:
See also references of EP 3839266A4
Attorney, Agent or Firm:
HIROWA PATENT FIRM (JP)
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