Title:
WORK MACHINE
Document Type and Number:
WIPO Patent Application WO/2023/162684
Kind Code:
A1
Abstract:
A work machine comprises a hydraulic actuator, a closed circuit pump that is connected to the hydraulic actuator in a closed circuit and that supplies and discharges hydraulic oil to and from the hydraulic actuator, an open circuit pump that is connected to the hydraulic actuator in an open circuit and that supplies hydraulic oil to the hydraulic actuator, a charge pump, a charge flow path that guides hydraulic oil discharged from the charge pump to the closed circuit, a surplus oil discharge device that discharges surplus hydraulic oil in the closed circuit to the charge flow path, and a controller that controls the discharge capacities of the closed circuit pump and the open circuit pump. When the pressure in the charge flow path transitions from being equal to or greater than a predetermined pressure threshold to being less than the pressure threshold, or when a work device transitions from not performing excavation work to performing excavation work, the controller increases the discharge capacity of the open circuit pump or reduces the discharge capacity of the closed circuit pump.
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Inventors:
KOWATARI YOICHI (JP)
KOFUNA SHUUHEI (JP)
HAYASHI TOMOAKI (JP)
KOFUNA SHUUHEI (JP)
HAYASHI TOMOAKI (JP)
Application Number:
PCT/JP2023/004058
Publication Date:
August 31, 2023
Filing Date:
February 07, 2023
Export Citation:
Assignee:
HITACHI CONSTRUCTION MACH CO (JP)
International Classes:
F15B11/08; E02F9/22; F15B21/047
Attorney, Agent or Firm:
KAICHI IP (JP)
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