US 12,325,979 B2
Working machine
Kazuki Ueda, Osaka (JP); Yuji Fukuda, Osaka (JP); and Ryota Hamamoto, Osaka (JP)
Assigned to KUBOTA CORPORATION, Osaka (JP)
Filed by KUBOTA CORPORATION, Osaka (JP)
Filed on Dec. 2, 2022, as Appl. No. 18/074,177.
Claims priority of application No. 2021-205375 (JP), filed on Dec. 17, 2021.
Prior Publication US 2023/0193595 A1, Jun. 22, 2023
Int. Cl. E02F 9/22 (2006.01); E02F 9/20 (2006.01); F15B 15/18 (2006.01)
CPC E02F 9/2253 (2013.01) [E02F 9/2004 (2013.01); E02F 9/2267 (2013.01); F15B 15/18 (2013.01); E02F 9/2285 (2013.01); E02F 9/2292 (2013.01); E02F 9/2296 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A working machine, comprising:
a prime mover;
a travel pump driven by power of the prime mover to deliver a hydraulic fluid;
a travel motor rotated by the hydraulic fluid delivered by the travel pump;
a machine body where the prime mover, the travel pump, and the travel motor are provided;
a travel switching valve switchable to a first state in which a rotation speed of the travel motor is capable of being increased up to a first maximum speed, and to a second state in which the rotation speed of the travel motor is capable of being increased up to a second maximum speed that is greater than the first maximum speed;
a travel operation device including an operation valve operable to change a pressure of a hydraulic fluid to operate the travel pump in accordance with an operation of an operation member; and
a controller, including a CPU, configured or programmed to decrease a supply amount of the hydraulic fluid from the travel pump to the travel motor based on a travel state of the machine body when performing either one of a speed-increase operation of switching the travel switching valve from the first state to the second state and a speed-decrease operation of switching the travel switching valve from the second state to the first state, wherein
when the speed-increase operation is performed, the controller switches the travel switching valve from the first state to the second state in a restoration period in which the supply amount to the travel motor after being decreased is being restored or in an after-restoration period in which the supply amount to the travel motor has been restored.