A gas turbine engine for an aircraft has an engine core having a turbine, compressor, and core shaft connecting the turbine and compressor; a fan upstream the engine core, the fan having fan blades; and a gearbox. The gearbox receives an input from a core shaft and outputs drive to a fan to drive the fan at a lower rotational speed than the core shaft. The gearbox is an epicyclic gearbox and has a sun gear, planet gears, ring gear, and planet carrier on which the planet gears are mounted. The gearbox has a gear mesh stiffness between the planet gears and the ring gear and a gear mesh stiffness between the planet gears and the sun gear. The gear mesh stiffness between the planet gears and the ring gear divided by that between the planet gears and the sun gear is in the range from 0.90 to 1.28.

An article of manufacture comprises a first component having a first mating surface and a second component having a second mating surface. The first component may include an aperture having internal splines or gear teeth, and/or an outer perimeter having external splines or gear teeth. The first and second components are disposed such that a gap is provided between the first and second mating surfaces. Brazing material is disposed between the first and second mating surfaces so as to mechanically couple the first and second components. The first component may be made of a powdered metal or a non-powdered metal, and the second component may be made of the other of such two metals. In one embodiment, the first component may be a planetary carrier plate portion having internal splines and the second component may be a planetary carrier spider portion.

The invention relates to a pivot pin (5) for an epicyclic gear train sliding bearing, having axially opposed, laterally open circumferential grooves (25a) providing flexibility to the pivot pin, each groove having a radial width and at least one depth (P). At least one of the circumferential grooves (25a,25b) has a said width and/or depth (P) which varies circumferentially.

The invention relates to a pivot (60) for a sliding bearing of an epicyclic train, comprising an annular wall defining an axial passage and comprising a first (52c) and a second annular groove opening axially in opposite directions and each defined by two coaxial inner (52a) and outer (52b) annular branches formed at the axial ends of the annular wall. According to the invention, the pivot comprises a plurality of first holes (60a) opening at a first end into the first annular groove (52c) and at a second opposite end into the second annular groove, these holes being made over an angular sector of between 5 and 330.

An epicyclic gear train including a central sun gear, an outer ring gear, and a number of planet gears which are mounted to a planet carrier. The planet carrier includes a centrally disposed torque transfer coupling with a torque transmission point at an axial end thereof. First and second carrier plates extend radially from the torque transfer coupling and are axially spaced apart to support the planet gears therebetween at aligned gear mounting points. The first carrier plate is closer to the torque transfer point than the second carrier plate. The second carrier plate has a stiffness that is greater than that of the first carrier plate.

The invention relates to a pivot pin (5) for an epicyclic gear train sliding bearing, the pivot pin having a portion (23) forming a central shank, extending around an axial passage (15), and axially opposed, axially open circumferential grooves (25a,25b) which radially separate two axially opposed lateral end portions (230a,230b) of the central shank from two cantilevered lateral portions (27a,27b). With respect to a plane (33) perpendicular to said axis of the axial passage (15) and passing through the axial middle of the axial passage, the axial distance between said plane (33) and the bottom end of one of the circumferential grooves (25a) is smaller than the axial distance between said plane and the bottom end of the axially opposed circumferential groove (25b).

The invention relates to a pivot pin (5) for an epicyclic gear train sliding bearing, the pivot pin having axially opposed, laterally open circumferential grooves (25a), providing flexibility to the pivot pin and which radially separate two axially opposite lateral end portions of a central shank from two lateral cantilevered portions (27a,27b) of the pivot pin. At least one of the cantilevered lateral portions is hollowed out by at least one recess (65a).

The invention relates to a pivot (58) for a sliding bearing of an epicyclic train, comprising an annular wall (50) defining an axial passage (51) and comprising a first (52c) and a second (54c) annular groove opening axially in opposite directions (L1, L2) and each defined by two coaxial inner (52a, 54a) and outer (52b, 54b) annular branches formed at the axial ends of the annular wall (50). According to the invention, the recesses (60) are made in at least one bottom wall (52d, 54d) of one of the annular grooves (52c, 54c).

A transmission in particular for wind power generators, with an epicyclic planetary gear arrangement having a sun gear, a ring gear, multiple planet gears and a planet carrier. The planet gears have planet gear teeth in mesh with sun gear teeth and ring gear teeth. Each planet gear is rotatably mounted via a radial slide bearing on a planet pin that is non-rotatably connected to the planet carrier. Each slide bearing includes a bearing hub positioned between the planet pin and the planet gear, which is non-rotatably connected to the planet pin. Between the bearing hub and the planet pin an annular support is formed, which seen in the axial direction has a smaller dimension than the bearing hub and/or a smaller dimension than the planet gear teeth of the planet gear.

A precision planetary gear comprising: a pinion; a movable annular gear; a fixed annular gear; one or more planet gears; wherein each planet gear simultaneously meshes with the pinion, the fixed annular gear and the movable annular gear; the pinion comprising a gear with a beveloid toothing; each planet gear comprising a gear with a beveloid toothing; wherein a beveloid toothing has a correction, which linearly varies along the longitudinal direction of the tooth; wherein each tooth of the beveloid toothing has a thickness and a height which increase moving from the apex of said beveloid gear along the longitudinal direction of the tooth.