Title:
HYDRAULIC CONTROL DEVICE FOR WORKING MACHINE
Document Type and Number:
WIPO Patent Application WO/2018/179574
Kind Code:
A1
Abstract:
This hydraulic control device comprises a pilot pressure control device (21) that variably controls pilot pressure supplied to a hydraulic pilot part of a directional control valve (14). The pilot pressure control device (21) includes first solenoid valves (22, 23) that selectively connect first output ports (22C, 23C) to first pump ports (22A, 23A) or first tank ports (22B, 23B) and perform switching control for the directional control valve (14) in accordance with an electric signal from a controller (30), a second solenoid valve (25) that selectively connects a second output port (25C) to a second pump port (25A) or a second tank port (25B) in accordance with the electric signal, a pilot pressure supply pipeline (26), and a tank pipeline (27). The second solenoid valve (25) causes pressure oil flowing from the second pump port (25A) to the second output port (25C) to flow back to the tank pipeline (27, 60), and warms up the pilot pressure control device (21).
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Inventors:
IKEDO YUKI (JP)
KANEZAWA HIROSHI (JP)
ITO HIDEAKI (JP)
NISHIHATA JUN (JP)
KANEZAWA HIROSHI (JP)
ITO HIDEAKI (JP)
NISHIHATA JUN (JP)
Application Number:
PCT/JP2017/041316
Publication Date:
October 04, 2018
Filing Date:
November 16, 2017
Export Citation:
Assignee:
HITACHI CONSTRUCTION MACH CO (JP)
International Classes:
E02F9/20; E02F9/22; F15B11/00; F15B11/08; F15B21/04
Foreign References:
| JP2000220768A | 2000-08-08 | |||
| JPS62246606A | 1987-10-27 |
Attorney, Agent or Firm:
HIROWA PATENT FIRM (JP)
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