US RE50,366 E1
Hydraulic system for work machine, and work machine
Yuji Fukuda, Sakai (JP); Kazuyoshi Arii, Sakai (JP); Keisuke Miura, Sakai (JP); Ryosuke Kinugawa, Sakai (JP); Ikuhiro Uotani, Sakai (JP); Satoshi Tajima, Sakai (JP); Ryohei Sumiyoshi, Sakai (JP); and Kunihiro Suzuki, Sakai (JP)
Assigned to KUBOTA CORPORATION, Osaka (JP)
Filed by KUBOTA CORPORATION, Osaka (JP)
Filed on Apr. 28, 2021, as Appl. No. 17/242,333.
Application 17/242,333 is a continuation of application No. PCT/JP2015/054922, filed on Feb. 23, 2015.
Application 17/242,333 is a reissue of application No. 15/390,536, filed on Dec. 26, 2016, granted, now 10,316,496, issued on Jun. 11, 2019.
Claims priority of application No. 2014-202381 (JP), filed on Sep. 30, 2014.
Int. Cl. E02F 9/22 (2006.01); E02F 3/34 (2006.01); F15B 11/042 (2006.01); F15B 11/16 (2006.01); F15B 13/042 (2006.01); F16H 61/4035 (2010.01); F16H 61/421 (2010.01); F16H 61/423 (2010.01)
CPC E02F 9/2228 (2013.01) [E02F 9/2253 (2013.01); E02F 9/2267 (2013.01); E02F 9/2285 (2013.01); E02F 9/2289 (2013.01); F15B 11/0426 (2013.01); F15B 11/16 (2013.01); F15B 13/0426 (2013.01); F16H 61/4035 (2013.01); F16H 61/421 (2013.01); F16H 61/423 (2013.01); E02F 3/3414 (2013.01); F15B 2013/0428 (2013.01); F15B 2211/30565 (2013.01); F15B 2211/31582 (2013.01); F15B 2211/327 (2013.01); F15B 2211/35 (2013.01); F15B 2211/355 (2013.01); F15B 2211/36 (2013.01); F15B 2211/6316 (2013.01); F15B 2211/6355 (2013.01); F15B 2211/665 (2013.01); F15B 2211/6654 (2013.01); F15B 2211/67 (2013.01); F15B 2211/71 (2013.01); F15B 2211/8606 (2013.01)] 27 Claims
OG exemplary drawing
 
1. A hydraulic system for a work machine, comprising:
a hydraulic pump to supply a pilot fluid;
a hydraulic switch valve to be switched to a plurality of switching positions based on a pilot pressure, the pilot pressure being a pressure of the pilot fluid supplied from the hydraulic pump;
a direction switch valve to apply a first pilot pressure to the hydraulic switch valve to switch the hydraulic switch valve into one of the plurality of switching positions; and
a pressure applying device to apply a second pilot pressure to the hydraulic switch valve, the second pilot pressure being lower than the first pilot pressure,
wherein the pressure applying device includes
a second fluid tube connecting the direction switch valve to the hydraulic switch valve,
a fourth [ an other ] fluid tube connecting the hydraulic pump to the direction switch valve, and
a fourth throttle to set the pilot pressure in the direction switch valve to the second pilot pressure.