US 11,725,364 B2
Hydraulic system of working machine
Yuji Fukuda, Sakai (JP); Jun Tomita, Sakai (JP); Yuya Konishi, Sakai (JP); Toshiya Tani, Sakai (JP); and Daisuke Sakurai, Sakai (JP)
Assigned to KUBOTA CORPORATION, Osaka (JP)
Filed by KUBOTA CORPORATION, Osaka (JP)
Filed on Jun. 2, 2022, as Appl. No. 17/830,473.
Claims priority of application No. 2021-094550 (JP), filed on Jun. 4, 2021.
Prior Publication US 2022/0389680 A1, Dec. 8, 2022
Int. Cl. E02F 9/22 (2006.01); F15B 21/0427 (2019.01); F15B 13/02 (2006.01)
CPC E02F 9/2228 (2013.01) [E02F 9/2242 (2013.01); E02F 9/2253 (2013.01); E02F 9/2267 (2013.01); E02F 9/2285 (2013.01); F15B 13/02 (2013.01); F15B 21/0427 (2019.01); E02F 9/2292 (2013.01); E02F 9/2296 (2013.01); F15B 2211/20576 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A hydraulic system of a working machine, comprising:
a hydraulic pump to output a hydraulic fluid;
at least one proportional valve to deliver the hydraulic fluid output from the hydraulic pump to a supply target;
a valve body that includes the proportional valve;
a heat-up fluid passage that is provided in the valve body and into which the hydraulic fluid output from the hydraulic pump flows;
at least one switching valve switchable between an open position in which the hydraulic fluid having passed through the heat-up fluid passage is supplied therethrough to a hydraulic device and a closed position in which the hydraulic fluid having passed through the heat-up fluid passage is not supplied therethrough to the hydraulic device and the hydraulic fluid from the hydraulic device is allowed to flow therethrough to be returned;
a controller configured or programmed to operate the switching valve and the proportional valve; and
a return circuit through which the hydraulic fluid having flown into the heat-up fluid passage is returned as a result of at least one of the switching valve and the proportional valve being operated by the controller.