Title:
HYDRAULIC EXCAVATOR
Document Type and Number:
WIPO Patent Application WO/2020/262201
Kind Code:
A1
Abstract:
This hydraulic excavator is provided with: a control valve unit which controls the flow of pressure oil supplied from a hydraulic pump to a plurality of hydraulic actuators; a plurality of operation lever devices which output pilot pressure for driving the control valve unit using discharge pressure of a pilot pump as source pressure; a solenoid valve unit configured to include a plurality of solenoid pressure-reducing valves provided between the plurality of operation lever devices and the control valve unit; and a controller which calculates speed limits of the plurality of hydraulic actuators on the basis of signals from a plurality of posture sensors and controls the opening degrees of the solenoid pressure-reducing valves. While boom raising operation signals are output from the operation lever devices, control is performed for arm crowding and arm dumping, so that the opening degrees of the solenoid pressure-reducing valves are controlled to be greater than those opening degrees based on the speed limits.
Inventors:
IGARASHI TERUKI (JP)
NARAZAKI AKIHIRO (JP)
ITOU MASAMICHI (JP)
NARAZAKI AKIHIRO (JP)
ITOU MASAMICHI (JP)
Application Number:
PCT/JP2020/024023
Publication Date:
December 30, 2020
Filing Date:
June 18, 2020
Export Citation:
Assignee:
HITACHI CONSTRUCTION MACH CO (JP)
International Classes:
E02F3/43; E02F9/20; F15B11/08
Domestic Patent References:
| WO2018008188A1 | 2018-01-11 | |||
| WO1995030059A1 | 1995-11-09 |
Foreign References:
| JP2003247504A | 2003-09-05 | |||
| JP2016061307A | 2016-04-25 | |||
| JP6062115B1 | 2017-01-18 | |||
| JP6062115B1 | 2017-01-18 |
Other References:
See also references of EP 3992371A4
Attorney, Agent or Firm:
KAICHI IP (JP)
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