Title:
油圧システム
Document Type and Number:
Japanese Patent JP6799480
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To actuate a hydraulic actuator even in the case where a solenoid proportional valve for unloading valve fails and a secondary pressure of the solenoid proportional valve becomes zero.SOLUTION: A hydraulic system includes: an operation device 4; a control valve 3 for increasing an opening area of a passage for supplying a hydraulic oil to a hydraulic actuator 24 as an operation signal outputted from the operation device becomes larger; a variable displacement type pump 21; a first solenoid proportional valve 6 and a second solenoid proportional valve 7 for outputting a higher secondary pressure as the operation signal outputted from the operation device becomes larger; a regulator 22 for increasing a tilting angle of the pump as the secondary pressure outputted from the first solenoid proportional valve becomes higher; an unloading valve 5A in which an opening area reduces from a fully open state toward a fully closed state as a pilot pressure guided to a pilot port 5c becomes higher; and a high pressure selection valve 8 for selecting a higher pressure out of the secondary pressure outputted from the first solenoid proportional valve and the secondary pressure outputted from the secondary solenoid proportional valve and for guiding it to the pilot port of the unloading valve.SELECTED DRAWING: Figure 1
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Inventors:
Tetsuhiro Kondo
Hideyasu Muraoka
Naoki Hata
Hideyasu Muraoka
Naoki Hata
Application Number:
JP2017043489A
Publication Date:
December 16, 2020
Filing Date:
March 08, 2017
Export Citation:
Assignee:
Kawasaki Heavy Industries, Ltd.
International Classes:
F15B20/00; E02F9/22; F15B11/00; F15B11/02; F15B11/08
Domestic Patent References:
| JP10061604A | ||||
| JP2004360898A |
Attorney, Agent or Firm:
Patent business corporation Yuko patent office