	US 12,429,071 B2
	Pilot pressure control device
Hideki Nakajima, Akashi (JP); and Toshikazu Koga, Akashi (JP)
Assigned to Caterpillar SARL, Geneva (CH)
Appl. No. 18/684,775
Filed by Caterpillar SARL, Geneva (CH)
PCT Filed Sep. 1, 2022, PCT No. PCT/EP2022/025409 § 371(c)(1), (2) Date Feb. 19, 2024, PCT Pub. No. WO2023/036463, PCT Pub. Date Mar. 16, 2023.
Claims priority of application No. 2021-145466 (JP), filed on Sep. 7, 2021.
Prior Publication US 2025/0027516 A1, Jan. 23, 2025
Int. Cl. F15B 13/042 (2006.01); E02F 9/22 (2006.01); F15B 11/16 (2006.01)

CPC F15B 13/0426 (2013.01) [E02F 9/2235 (2013.01); E02F 9/226 (2013.01); E02F 9/2285 (2013.01); E02F 9/2296 (2013.01); F15B 11/16 (2013.01); F15B 2211/30525 (2013.01); F15B 2211/329 (2013.01); F15B 2211/355 (2013.01); F15B 2211/625 (2013.01); F15B 2211/6313 (2013.01); F15B 2211/6355 (2013.01); F15B 2211/665 (2013.01); F15B 2211/6653 (2013.01); F15B 2211/71 (2013.01)]

4 Claims

1. A pilot pressure control device configured to control a pilot pressure of a fluid pressure circuit comprising a main circuit configured to control working fluid discharged from a pump by a control valve to drive a fluid pressure actuator; and a pilot circuit configure to supply a pressure which has been controlled so as to depressurize a portion of the working fluid discharged from the pump as a pilot pressure source, the pilot pressure control device comprising a controller configured, when a pump pressure drops to a predetermined pressure or below resulting from the drive of the fluid pressure actuator, to control so as to throttle an opening of a spool that causes the decrease in the pump pressure.