Power transmission gearbox and an aircraft

Patent metadata

Field	Value
Publication number	US-10240662-B2
Application number	US-201615207779-A
Country	US
Kind code	B2
Filing date	Jul 12, 2016
Priority date	Jul 16, 2015
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A power transmission gearbox having at least one driving gear with spur teeth presenting a large radius. The gearbox includes at least one mechanical outlet drive system suitable for driving an accessory, the mechanical outlet drive system having a gear with face teeth referred to as an “accessory pinion”, the accessory pinion presenting a “small” radius (R2) lying orthogonally between each face tooth and its axis of rotation, the small radius (R2) being smaller than the large radius (R1).

First claim

What is claimed is:

1. A power transmission gearbox having at least one driving spur gear that is movable in rotation about an axis of rotation, the driving spur gear with spur teeth and having a first radius lying orthogonally between each spur tooth of the driving spur gear and the axis of rotation, wherein the gearbox includes at least one mechanical outlet drive system suitable for driving an accessory, the mechanical outlet drive system comprising a driven face gear configured as an accessory pinion with face teeth, the face gear being movable in rotation about a drive axis that intersects the axis of rotation, at least one face tooth of the face gear being engaged with at least one spur tooth of the driving spur gear, the face gear having a second radius lying orthogonally between each face tooth of the face gear and the drive axis, the second radius being less than the first radius;
wherein the gearbox includes at least one speed reduction stage suitable for driving a rotor, and the driving spur gear is a gear for setting the speed reduction stage into motion via at least one power transmission shaft, the at least one power transmission shaft movable in rotation about the axis of rotation of the driving spur gear and directly coupled to the driving spur gear and a gear of the speed reduction stage.

2. A gearbox according to claim 1 , wherein the gearbox includes at least one mechanical inlet member engaged with a drive gear, the drive gear setting the speed reduction stage into motion via the at least one power transmission shaft, each mechanical inlet member being suitable for being driven by an engine, the driving spur gear being represented either by the drive gear, or by an inlet gear of the mechanical inlet member, or by a complementary gear constrained to rotate with the drive gear.

3. A gearbox according to claim 1 , wherein at least one mechanical outlet drive system has a drive shaft secured to the face gear of the mechanical outlet drive system, the drive shaft being suitable for engaging with an accessory, the drive shaft suitable for rotation about the drive axis.

4. A gearbox according to claim 3 , wherein the drive shaft projects outside a casing of the gearbox.

5. A gearbox according to claim 1 , wherein the gearbox includes a plurality of mechanical outlet drive systems distributed in azimuth around the driving spur gear.

6. A gearbox according to claim 5 , wherein the mechanical outlet drive systems are uniformly distributed in azimuth around the driving spur gear.

7. A gearbox according to claim 1 , wherein at least two face gears of two mechanical outlet drive systems are offset from each other in elevation, one face gear rotating in a counterclockwise direction and the other face gear rotating in a clockwise direction.

8. A power transmission architecture having a gearbox and at least one accessory, wherein the gearbox is according to claim 1 , at least one accessory being connected to a mechanical outlet drive system.

9. A power transmission architecture according to claim 8 , wherein the gearbox includes a gearbox casing, each driving spur gear and each face gear being arranged in the gearbox casing, at least one accessory including an accessory casing fastened to the gearbox casing.

10. A power transmission architecture according to claim 8 , wherein each accessory is connected to its own mechanical outlet drive system, which is dedicated to that accessory.

11. An aircraft including a rotor, wherein the aircraft includes a power transmission architecture according to claim 8 , the rotor being driven in rotation by the gearbox.

12. A gearbox according to claim 1 , wherein the face gear has a top face, a bottom face, and an edge face extending in elevation along the axis of rotation, the edge face positioned between and connecting the top face to the bottom face, the face teeth of the face gear extending in elevation from the top face.

13. A gearbox according to claim 12 , wherein the driving spur gear has a top disk, a bottom disk, and an edge face extending in elevation along the axis of rotation, the edge face positioned between and connecting the top disk to the bottom disk, the edge face defining the spur teeth of the driving spur gear.

14. The gearbox according to claim 13 , wherein the face gear is configured to move axially without influencing a bearing of the face teeth of the face gear against the spur teeth of the driving spur gear.

15. A power transmission gearbox for a rotorcraft, the gearbox comprising:
a driving spur gear rotating about an axis of rotation, the driving spur gear having a top disk, a bottom disk, and an edge face extending in elevation along the axis of rotation, the edge face positioned between and connecting the top disk to the bottom disk, the edge face defining spur teeth of the driving spur gear, wherein the driving spur gear has a first radius lying orthogonally between each spur tooth of the driving spur gear and the axis of rotation;
a speed reducing stage for driving a rotor of the rotorcraft, the speed reducing stage having a plurality of gears;
a power transmission shaft directly coupled to the driving spur gear and to one of the plurality of gears of the speed reducing stage, the power transmission shaft constrained for rotation with the driving spur gear and the one of the plurality of gears of the speed reducing stage, the power transmission shaft rotating about the axis of rotation; and
a mechanical outlet drive system for driving an accessory, the drive system having a driven face gear rotating about a drive axis and configured as an accessory pinion, the face gear having a top face, a bottom face, and an edge face extending in elevation along the drive axis, the edge face positioned between and connecting the top face to the bottom face, the face gear having face teeth extending in elevation from the top face, wherein the face gear has a second radius lying orthogonally between each face tooth of the face gear and the drive axis, the second radius being less than the first radius, wherein the drive axis intersects the axis of rotation, and wherein at least one face tooth of the face gear is in meshed engagement with at least one spur tooth of the driving spur gear.

16. The power transmission gearbox according to claim 15 wherein the face gear is configured to move axially without influencing a bearing of the face teeth of the face gear against the spur teeth of the driving spur gear.

17. The power transmission gearbox of claim 15 further comprising another mechanical outlet drive system for driving another accessory, the another drive system having another driven face gear rotating about another drive axis and configured as another accessory pinion, the another face gear having another top face, another bottom face, and another edge face extending in elevation along the another drive axis, the another edge face positioned between and connecting the another top face to the another bottom face, the face teeth of the another face gear extending in elevation from the another top face, wherein the another face gear has another radius lying orthogonally between each face tooth of the another face gear and the another drive axis, the another radius being less than the first radius, wherein the another drive axis intersects the axis of rotation, and wherein at least one face tooth of the another face gear is in meshed engagement with at least one spur tooth of the driving spur gear.

18. The power transmission gearbox of claim 17 wherein the face gear and the another face gear are axially offset and space

Assignees

• Airbus Helicopters

Inventors

• Thomassey Lionel

Classifications

• F16H55/22

  for transmissions with crossing shafts, especially worms, worm-gears · CPC title

• F16H1/12 Primary

  with non-parallel axes · CPC title

• F02C7/32

  Arrangement, mounting, or driving, of auxiliaries · CPC title

• F05D2260/4031

  as in toothed gearing · CPC title

• B64D2033/0213

  specially adapted for auxiliary power units (APU's) · CPC title