US 11,725,592 B2
Aeronautical propulsion system having a low leakage flow rate and improved propulsion efficiency
Caroline Marie Frantz, Moissy-Cramayel (FR); Gilles Alain Marie Charier, Moissy-Cramayel (FR); and Adrien Louis Simon, Moissy-Cramayel (FR)
Assigned to SAFRAN AIRCRAFT ENGINES, Paris (FR); and SAFRAN TRANSMISSION SYSTEMS, Colombes (FR)
Appl. No. 17/783,950
Filed by SAFRAN AIRCRAFT ENGINES, Paris (FR); and SAFRAN TRANSMISSION SYSTEMS, Colombes (FR)
PCT Filed Dec. 11, 2020, PCT No. PCT/FR2020/052390
§ 371(c)(1), (2) Date Jun. 9, 2022,
PCT Pub. No. WO2021/116620, PCT Pub. Date Jun. 17, 2021.
Claims priority of application No. 1914191 (FR), filed on Dec. 11, 2019.
Prior Publication US 2023/0007929 A1, Jan. 12, 2023
Int. Cl. F02C 7/36 (2006.01)
CPC F02C 7/36 (2013.01) [F05D 2220/323 (2013.01); F05D 2220/324 (2013.01); F05D 2220/325 (2013.01); F05D 2240/54 (2013.01); F05D 2260/40311 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A propulsion system comprising:
a drive shaft movable in rotation about an axis of rotation;
a fan;
a fan shaft configured to drive the fan in rotation about the axis of rotation;
a reduction mechanism coupling the drive shaft and the fan shaft, wherein the reduction mechanism has a first reduction stage and a second reduction stage and includes:
a sun gear, centered on the axis of rotation and configured to be driven in rotation by the drive shaft,
a ring gear, coaxial with the sun gear and configured to drive in rotation the fan shaft about the axis of rotation, and
planet gears distributed circumferentially about the axis of rotation between the sun gear and the ring gear, each planet gear comprising a first portion forming the first reduction stage which is meshed with the sun gear and a second portion forming the second reduction stage which is meshed with the ring gear, a diameter of the first portion being different from a diameter of the second portion, the first portion of the planet gears extending between the second portion of the planet gears and the fan.