US 12,247,373 B2
Hydraulic drive system and construction machine
Etsuro Komori, Tokyo (JP)
Assigned to NABTESCO CORPORATION, Tokyo (JP)
Filed by NABTESCO CORPORATION, Tokyo (JP)
Filed on Oct. 27, 2023, as Appl. No. 18/496,276.
Claims priority of application No. 2022-190160 (JP), filed on Nov. 29, 2022.
Prior Publication US 2024/0175242 A1, May 30, 2024
Int. Cl. E02F 9/22 (2006.01); F15B 11/16 (2006.01)
CPC E02F 9/2203 (2013.01) [E02F 9/2232 (2013.01); E02F 9/2296 (2013.01); F15B 11/16 (2013.01); F15B 2211/3138 (2013.01); F15B 2211/7058 (2013.01); F15B 2211/7107 (2013.01); F15B 2211/763 (2013.01); F15B 2211/782 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A hydraulic drive system, comprising:
a hydraulic pump configured to discharge a hydraulic fluid;
a plurality of variable displacement actuators each configured to receive a pressure of the hydraulic fluid discharged from the hydraulic pump to operate a corresponding one of a plurality of drive parts; and
a control unit configured to control respective displacement varying parts of the plurality of variable displacement actuators,
wherein the control unit is configured to:
acquire a common target pressure that is predetermined and common to the plurality of variable displacement actuators, and
control the displacement varying parts of the variable displacement actuators, based on sensed pressures in fluid inflow parts of the variable displacement actuators in operation among the plurality of variable displacement actuators, such that the pressures in the fluid inflow parts of the variable displacement actuators in operation approach the acquired common target pressure that is common to the plurality of variable displacement actuators.
 
6. A construction machine, comprising:
a plurality of drive parts; and
a hydraulic drive system configured to receive a pressure of a hydraulic fluid to operate the plurality of drive parts,
wherein the hydraulic drive system includes:
a hydraulic pump configured to discharge the hydraulic fluid;
a plurality of variable displacement actuators each configured to receive a pressure of the hydraulic fluid discharged from the hydraulic pump to operate a corresponding one of the plurality of drive parts; and
a control unit configured to control respective displacement varying parts of the plurality of variable displacement actuators,
wherein the control unit is configured to:
acquire a common target pressure that is predetermined and common to the plurality of variable displacement actuators, and
control the displacement varying parts of the variable displacement actuators, based on sensed pressures in fluid inflow parts of the variable displacement actuators in operation among the plurality of variable displacement actuators, such that the pressures in the fluid inflow parts of the variable displacement actuators in operation approach the acquired common target pressure that is common to the plurality of variable displacement actuators.