Title:
WORK MACHINE
Document Type and Number:
WIPO Patent Application WO/2021/200024
Kind Code:
A1
Abstract:
The present invention is provided with: a variable capacity-type hydraulic pump 18; an arm cylinder 15 that is driven by pressure oil discharged from the hydraulic pump 18; an operation lever 26 that outputs an operation signal for activating the arm cylinder 15; a control valve 27 that controls supply/discharge of the pressure oil with respect to the arm cylinder 15; a bypass oil path 33 that discharges the pressure oil to a hydraulic oil tank 30, without passage through the control valve 27, from a meter-out flow path through which the pressure oil discharged from the arm cylinder 15 flows; a bypass flow rate control valve 32 that controls the flow rate of the pressure oil in the bypass oil path 33; and a control device 19 that controls the opening area of the bypass flow rate control valve 32 in accordance with load pressure of the arm cylinder 15 and that, even when the estimated value of pump pressure after change of the opening area of the bypass flow rate control valve 32 becomes low, performs control for retaining a tilt angle before the change of the opening area. Accordingly, it is possible to suppress degradation of operability when the load pressure of a hydraulic actuator has rapidly decreased.
More Like This:
| WO/2013/121922 | CONSTRUCTION MACHINERY |
Inventors:
IMAI YUSUKE (JP)
AMANO HIROAKI (JP)
OTA YASUNORI (JP)
AMANO HIROAKI (JP)
OTA YASUNORI (JP)
Application Number:
PCT/JP2021/009934
Publication Date:
October 07, 2021
Filing Date:
March 11, 2021
Export Citation:
Assignee:
HITACHI CONSTRUCTION MACH CO (JP)
International Classes:
F15B11/02; E02F9/22; F15B11/044; F15B11/08; F15B11/16
Foreign References:
| JP2016075358A | 2016-05-12 | |||
| JP2001329883A | 2001-11-30 | |||
| JP2004360898A | 2004-12-24 | |||
| JPH09317703A | 1997-12-09 | |||
| US20180372088A1 | 2018-12-27 |
Attorney, Agent or Firm:
KAICHI IP (JP)
Download PDF: