US 11,939,044 B2
Landing gear system for an aircraft
Peter Sharpe, Bristol (GB)
Assigned to AIRBUS OPERATIONS LIMITED, Bristol (GB)
Appl. No. 17/604,352
Filed by AIRBUS OPERATIONS LIMITED, Bristol (GB)
PCT Filed Sep. 2, 2020, PCT No. PCT/EP2020/074507
§ 371(c)(1), (2) Date Oct. 15, 2021,
PCT Pub. No. WO2021/047980, PCT Pub. Date Mar. 18, 2021.
Claims priority of application No. 1913269 (GB), filed on Sep. 13, 2019.
Prior Publication US 2022/0177118 A1, Jun. 9, 2022
Int. Cl. B64C 25/22 (2006.01); F15B 15/22 (2006.01); F15D 1/00 (2006.01); B64C 25/34 (2006.01)
CPC B64C 25/22 (2013.01) [F15B 15/22 (2013.01); F15D 1/0025 (2013.01); B64C 25/34 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A landing gear system for an aircraft, wherein the system includes
a retractable landing gear assembly, and
a hydraulic actuator for actuating retraction of at least a part of the landing gear assembly from an extended configuration to a retracted configuration,
the hydraulic actuator including a piston that travels within a cylinder along a stroke length between a first position corresponding to the extended configuration of said part of the landing gear assembly and a second position corresponding to the retracted configuration of said part of the landing gear assembly, and
movement of the piston along its stroke length being snubbed for a portion of the stroke length when proximate to, and moving in a direction towards, one of the first position and the second position, and wherein the snubbing, if any, is less when moving in the opposite direction, there thus being provided asymmetric snubbing,
the asymmetric snubbing being provided by the flow of hydraulic fluid during both directions of travel of the piston through a passageway connected to a first hydraulic supply line and including a cross-sectional shape which tapers in one direction such that there is more snubbing for fluid flow in one direction than in the opposite direction, as a result of the shape of the passageway, and
wherein the passageway has a discharge coefficient of 0.9 or more in a flow direction corresponding to the snubbing, if any, when the piston is moving in said opposite direction.