US 12,173,475 B2
Work machine
Masatoshi Hoshino, Tsuchiura (JP); Seiji Hijikata, Tsukuba (JP); and Yasutaka Tsuruga, Ryugasaki (JP)
Assigned to Hitachi Construction Machinery Co., Ltd., Tokyo (JP)
Appl. No. 18/025,085
Filed by Hitachi Construction Machinery Co., Ltd., Tokyo (JP)
PCT Filed Dec. 15, 2021, PCT No. PCT/JP2021/046387
§ 371(c)(1), (2) Date Mar. 7, 2023,
PCT Pub. No. WO2022/180997, PCT Pub. Date Sep. 1, 2022.
Claims priority of application No. 2021-028971 (JP), filed on Feb. 25, 2021.
Prior Publication US 2023/0323634 A1, Oct. 12, 2023
Int. Cl. E02F 9/22 (2006.01); E02F 9/20 (2006.01); F15B 13/044 (2006.01); F15B 15/26 (2006.01)
CPC E02F 9/2203 (2013.01) [E02F 9/2004 (2013.01); E02F 9/2296 (2013.01); F15B 13/044 (2013.01); F15B 15/26 (2013.01); E02F 9/2285 (2013.01); E02F 9/2292 (2013.01); F15B 2211/426 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A work machine that includes
a hydraulic pump of a variable displacement type,
a hydraulic actuator driven by hydraulic fluid supplied from the hydraulic pump,
an operation lever for issuing an instruction of an action of the hydraulic actuator, and
a controller that controls a pump delivery flow rate that is a delivery flow rate of the hydraulic pump,
the work machine comprising:
a first timing sensor for sensing a first timing that is a timing immediately before the hydraulic actuator starts to act; and
a second timing sensor for sensing a second timing that is a timing immediately after the hydraulic actuator starts to act, wherein
the controller,
on a basis of a signal from the first timing sensor and
a signal from the second timing sensor,
controls, before the first timing is sensed, the pump delivery flow rate to a minimum delivery flow rate,
control, after the first timing is sensed but before the second timing is sensed, the pump delivery flow rate to a predetermined delivery flow rate that is greater than the minimum delivery flow rate, and
control, after the second timing is sensed, the pump delivery flow rate to a delivery flow rate according to an operation amount of the operation lever,
each one of the first timing sensor and the second timing sensor is a sensor that senses an operation amount of the operation lever, and
the controller is configured to
decide, as the first timing, a timing at which the operation amount of the operation lever sensed by the sensor becomes equal to or greater than a predetermined first operation amount, and
decide, as the second timing, an earlier one of a timing at which the operation amount of the operation lever sensed by the sensor becomes equal to or greater than a predetermined second operation amount that is greater than the first operation amount and a timing at which elapsed time after the operation amount of the operation lever becomes equal to or greater than the first operation amount becomes equal to or greater than predetermined time.