To secure an operation of a hydraulic actuator while preventing the generation of heat caused by relieving work oil at the time of a failure of a unified bleed-off valve, in a circuit structure that a group of hydraulic actuators are divided into two groups to drive both the groups with hydraulic oil discharged from a common pump.
A group of hydraulic actuators are divided into two groups A and B, and the unified bleed-off valves 27 and 28 are arranged in discharged lines 15 and 16 of first and second hydraulic pumps 7 and 8. Further, center bypass passages 21 and 22 are arranged on respective control valves 1-3 and 4-6 of both the groups A and B, and center bypass lines 23 and 24 are formed by connecting these center bypass passages in tandem. A manually-switching type bypass cut valve 35 for unloading work oil at the time of the failure of the unified bleed-off valves 27 and 28 is arranged at the most downstream side of the center bypass lines 23 and 24.
COPYRIGHT: (C)2007,JPO&INPIT
TAJI HIROSHI
YOSHIKAWA HIROSHI
MURASE KIMIHIKO
KAWASAKI PRECISION MACH LTD
| JP2005265016A | 2005-09-29 | |||
| JPH01320302A | 1989-12-26 | |||
| JP2007192344A | 2007-08-02 | |||
| JPH10131907A | 1998-05-22 | |||
| JP2005127413A | 2005-05-19 |
Takao Ito
Jiro Higuchi
Muramatsu Toshiro
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