Planetary gearbox system and method for operating a planetary gearbox system

Patent metadata

Field	Value
Publication number	US-10954813-B2
Application number	US-201816050526-A
Country	US
Kind code	B2
Filing date	Jul 31, 2018
Priority date	Aug 18, 2017
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

A planetary gearbox system with a ring gear, a sun gear, a carrier and planetary gears as parts in a geared aircraft turbofan engine, with one static part of the parts being in rest under nominal operation and with a kinematic switch device for decoupling the static part to become a rotatable part or with a kinematic switch device for coupling the rotatable part to become a static part. The invention also relates to a method for operating a planetary gearbox system.

First claim

The invention claimed is:

1. A planetary gearbox system of a geared aircraft turbofan engine, comprising:
a plurality of parts including:
a ring gear,
a sun gear,
a carrier,
planetary gears,

at least one kinematic switch device,
wherein a static part of the plurality of parts is in rest under nominal operation,
wherein the at least one kinematic switch device is suitable for at least one chosen from:
decoupling the static part to become rotatable, and
coupling a rotatable part of the plurality of parts to become static,

wherein the at least one kinematic switch device comprises two connecting parts and a position change mechanism to automatically trigger a position change in at least one of the two connecting parts relative to at least one chosen from the other of the two connecting parts and an engine part, from a first position into a second position in dependence of a non-nominal torque or a reversal in a direction of a torque effective on at least one chosen from one of the two connecting parts and the engine part, and
wherein the position change mechanism comprises at least one chosen from a helical spline connection between the two connecting parts, an explosive bolt device, an automatic clutch device and a hydraulic device,
wherein the two connecting parts are directly connected to at least one chosen from a shaft and the ring gear.

2. The planetary gearbox system according to claim 1 , wherein the static part which is decouplable or the rotatable part which is couplable is the ring gear of an epicyclic planetary gearbox system or the carrier of a star-design planetary gearbox system.

3. The planetary gearbox system according to claim 1 , wherein the at least one kinematic switch device includes at least one chosen from a mechanical fuse for decoupling the static part into a rotatable part and a clutch device for decoupling the static part or coupling the rotatable part.

4. The planetary gearbox system according to claim 1 , wherein the decoupling of the static part is triggered by a predetermined kinematic condition.

5. The planetary gearbox system according to claim 4 , wherein the predetermined kinematic condition comprises 1) a torque acting on one of the plurality of parts exceeding a threshold value or 2) a direction of torque acting on one of the plurality of parts changing direction.

6. The planetary gearbox system according to claim 1 , wherein the decoupling of the static part or coupling of the rotatable part is effected by the kinematic switch device operating an actuator.

7. The planetary gearbox system according to claim 1 , wherein the decoupled part generates additional power under rotation.

8. The planetary gearbox system according to claim 1 , and further comprising at least one chosen from:
wherein torque transmission characteristics of the helical spline connection are asymmetric relative to a torque applied to the helical spline connection, and
the automatic clutch device comprises a device for balancing axial loads.

9. The planetary gearbox system according to claim 1 , wherein:
in the first position, the two connecting parts are mechanically engaged with at least one chosen from each other and with the engine part, so that torque is transmittable between the two connecting parts, and
in the second position, the two connecting parts are mechanically disengaged from at least one chosen from each other and the engine part, enabling a free relative movement between the two connecting parts and the engine part.

10. The planetary gearbox system according to claim 1 , and further comprising at least one chosen from:
wherein at least one chosen from a first one and a second one of the two connecting parts is coupled to a ring gear mount of the gearbox,
wherein at least one chosen from the first one and the second one of the two connecting parts is rigidly connected to the ring gear mount of the gearbox,
wherein at least one chosen from the first one and the second one of the two connecting parts is one piece with the ring gear mount of the gearbox, and
wherein at least one chosen from the first one and the second one of the two connecting parts is coupled with a static structure of the aircraft turbofan engine.

11. The planetary gearbox system according to claim 1 , wherein at least one chosen from a first one and a second one of the two connecting parts is coupled to the static part.

12. The planetary gearbox system according to claim 1 , wherein the engine part is positioned in the first position fixedly relative to the two connecting parts and in the second position, at least one of the two connecting parts is movable relative to the engine part.

13. The planetary gearbox system according to claim 12 , comprising the automatic clutch device, wherein a first one and a second one of the two connecting parts each comprises a contact interface with the engine part, the contact interfaces being parallel to each other or angled to each other.

14. The planetary gearbox system according to claim 1 , wherein the engine part comprises a ring structure which is positioned in the first position between the two connecting parts, the two connecting parts also comprising ring structures.

15. The planetary gearbox system according to claim 1 , and further comprising a clamping preloading device to apply a predetermined force to the kinematic switch device.

16. The planetary gearbox system according to claim 15 , and further comprising an axial retention device.

17. The planetary gearbox system according to claim 1 , wherein a connection between at least one of the two connecting parts and the engine part comprises a high friction coating on at least one surface of an interface of the at least one of the two connecting parts and the engine part.

18. The planetary gearbox system according to claim 16 , wherein at least one chosen from a connection between the clamping preloading device and the engine part and a connection between the axial retention device and the at least one of the two connecting parts comprises a low friction coating on at least one surface.

19. The planetary gearbox system according to claim 1 , wherein the planetary gearbox system is coupled to a propulsive fan of the geared aircraft turbofan engine, the propulsive fan being suitable for at least one chosen from:
driving an electrical generator in windmilling operation conditions, and
being driven by external power source when decoupled through the automatic clutch device from a primary power source.

20. A method for operating a planetary gearbox system with a ring gear, a sun gear, a carrier and planetary gears as a plurality of parts in a geared aircraft turbofan engine, wherein a static part of the plurality of parts is in rest under nominal operation and the static part is decoupled with a kinematic switch device to become rotatable or a rotatable part is coupled with a kinematic switch device to become static,
wherein the kinematic switch device comprises two connecting parts and a position change mechanism to automatically trigger a position change in at least one of the two connecting parts relative to at least one chosen from the other of the two connecting parts and an engine part, from a first position into a second position in dependence of a non-nominal torque or a reversal in a direction of a torque effective on at least one chosen from one of the two connecting parts and the engine part, and
wherein the position change mechanism comprises at least one chosen from a helical spline connection betwee

Assignees

• Rolls Royce Deutschland Ltd & Co Kg

Inventors

• Wuestenberg Hannes

Classifications

• F16H57/10 Primary

  Braking arrangements · CPC title

• F16D13/42

  with means for increasing the effective force between the actuating sleeve or equivalent member and the pressure member · CPC title

• F16D13/48

  with means for increasing the effective force between the actuating sleeve or equivalent member and the pressure member · CPC title

• F16D9/00

  Couplings with safety member for disconnecting, e.g. breaking or melting member · CPC title

• F16H2035/103

  with drive interruption by structural failure of overload preventing means, e.g. using shear pins · CPC title