Aeronautical propulsion system

Abstract

An aeronautical propulsion system 1 uses a turbine-driven shaft 11 to drive a ducted fan section 2 having a fan shaft 20 through a reduction epicyclic gear train 19, with a ring gear 19b, and supported by a stator-mounted structure 19f, allowing the fan to rotate more slowly than the turbine. A coupling device 30 between the drive shaft and the gearbox accommodates shaft misalignment using shaft sections 300 linked by radially flexible elements 301, such as bellows or elastic flectors, at different axial distances from a first guiding system 23 supporting the fan shaft with an active part transmitting force between the fan shaft and a part fixed relative to the stator 19e, a reference plane P0 is equidistant from the axial ends of the first guiding system. A second guiding system 24 supports the drive shaft with thrust bearings, the thrust bearing 240 closest to the gearbox has an active part transmitting force between the drive shaft and a part fixed relative to the stator. The arrangement positions the second guiding system, stator-mounted structure, gearbox, specific guiding system bearing, and flexible elements at defined axial locations relative to the reference plane, the distances specified as relative ratios. [Figure 6]