Geared gas turbine engine and a gearbox

• US 10,458,274 B2
• Filed: 06/16/2017
• Issued: 10/29/2019
• Est. Priority Date: 07/12/2016
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: Doorbar, Phillip J, Madge, Jason J
• Primary Examiner(s): Newton, J. Todd
• Application Number:
  US15/625,523
• Publication Number:
  US 20180016938A1
• Time in Patent Office: 865 Days
• Field of Search: 4151221, 475331, 475344, 475345, 475901, 475902
• CPC Class Codes: F01D 15/08 Adaptations for driving, or combinations with, pumps
• CPC Class Codes: F01D 15/12 Combinations with mechanical gearing driven by multiple engines F01D13/00
• CPC Class Codes: F01D 25/005 Selecting particular materials
• CPC Class Codes: F01D 25/16 Arrangement of bearings; Supporting or mounting bearings in casings bearings per se F16C
• CPC Class Codes: F01D 5/06 Rotors for more than one axial stage, e.g. of drum or multiple disc type; Details thereof, e.g. shafts, shaft connections F01D5/022, F01D5/023 take precedence
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: F05D 2220/32 in gas turbines
• CPC Class Codes: F05D 2260/40311 of the epicyclical, planetary or differential type
• CPC Class Codes: F05D 2300/171 Steel alloys
• CPC Class Codes: F05D 2300/174 Titanium alloys, e.g. TiAl
• CPC Class Codes: F05D 2300/2261 of silicon
• CPC Class Codes: F05D 2300/2282 of boron
• CPC Class Codes: F05D 2300/2283 of silicon
• CPC Class Codes: F05D 2300/6032 Metal matrix composites [MMC]
• CPC Class Codes: F16H 1/28 with gears having orbital motion
• CPC Class Codes: F16H 57/08 of gearings with members having orbital motion
• CPC Class Codes: F16H 57/082 Planet carriers
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A gas turbine engine comprises a gearbox comprises a sun gear, an annulus gear, a plurality of planet gears and a carrier. The sun gear meshes with the planet gears and the planet gears mesh with the annulus gear. The planet gear carrier comprising a first ring, a second ring spaced axially from the first ring and a plurality of circumferentially spaced axles extending axially between the first ring and the second ring. Each planet gear is rotatably mounted on a respective one of the axles and the axles are arranged at a first radius. At least one of the first ring and the second ring comprises a metal matrix composite material ring and the metal matrix composite ring comprises a ring of reinforcing fibres and the ring of reinforcing fibres having a second radius greater than the first radius.

Claims

1. A gas turbine engine comprising a gearbox,

the gearbox comprising:

a sun gear;

an annulus gear;

a plurality of planet gears; and

a carrier,

the sun gear meshing with the planet gears and the planet gears meshing with the annulus gear;

the carrier comprising a first ring, a second ring spaced axially from the first ring, and a plurality of circumferentially spaced axles extending axially between the first ring and the second ring;

each planet gear being rotatably mounted on a respective one of the plurality of circumferentially spaced axles;

each of the plurality of circumferentially spaced axles being arranged at a first radius;

at least one of the first ring and the second ring comprising a metal matrix composite material;

the metal matrix composite material comprising a ring of reinforcing fibres; and

the ring of reinforcing fibres having a second radius greater than the first radius.

2. A gas turbine engine as claimed in claim 1, wherein

the first ring comprises a first metal matrix composite material and the second ring comprises a second metal matrix composite material;

the first metal matrix composite material comprises a first ring of reinforcing fibres, the first ring of reinforcing fibres having a second radius greater than the first radius; and

the second metal matrix composite material comprises a second ring of reinforcing fibres, the second ring of reinforcing fibres having a second radius greater than the first radius.

3. A gas turbine engine as claimed in claim 2, wherein the first ring and the second ring are secured together.

4. A gas turbine engine as claimed in claim 2, wherein the first metal matrix composite material comprises a metal matrix selected from a group consisting essentially of a steel matrix, a titanium matrix, and a titanium alloy matrix.

5. A gas turbine engine as claimed in claim 2, wherein the first metal matrix composite material comprises reinforcing fibres selected from a group consisting essentially of silicon carbide fibres, silicon nitride fibres, and boron nitride fibres.

6. A gas turbine engine as claimed in claim 2, wherein the second metal matrix composite material comprises a metal matrix selected from a group consisting essentially of a steel matrix, a titanium matrix, and a titanium alloy matrix.

7. A gas turbine engine as claimed in claim 2, wherein the second metal matrix composite material comprises reinforcing fibres selected from a group consisting essentially of silicon carbide fibres, silicon nitride fibres, and boron nitride fibres.

8. A gas turbine engine as claimed in claim 1, wherein each of the plurality of circumferentially spaced axles comprises a third metal matrix composite material, the third metal matrix composite material comprising reinforcing fibres extending axially between the first ring and the second ring.

9. A gas turbine engine as claimed in claim 8, wherein the third metal matrix composite material comprises a metal matrix selected from a group consisting essentially of a steel matrix, a titanium matrix, and a titanium alloy matrix.

10. A gas turbine engine as claimed in claim 8, wherein the third metal matrix composite material comprises silicon carbide fibres, silicon nitride fibres, or boron nitride fibres.

11. A gas turbine engine as claimed in claim 1, wherein each planet gear is rotatably mounted on the carrier by a bearing selected from a group consisting essentially of a journal bearing and at least one rolling element bearing.

12. A gas turbine engine as claimed in claim 11, wherein each planet gear is rotatably mounted on the carrier by two rolling element bearings.

13. A gas turbine engine as claimed in claim 1, wherein the carrier is connected to an output shaft and the annulus gear is connected to a static structure.

14. A gas turbine engine as claimed in claim 1, wherein the carrier is connected to a static structure and the annulus gear is connected to an output shaft.

15. A gas turbine engine as claimed in claim 1, wherein

the gas turbine engine comprises a propulsor, an intermediate-pressure compressor, a high-pressure compressor, a high-pressure turbine, and a low-pressure turbine;

the high-pressure turbine is arranged to directly drive the high-pressure compressor

the low-pressure turbine is arranged to directly drive the intermediate-pressure compressor; and

the low-pressure turbine is arranged to drive the propulsor via the gearbox.

16. A gas turbine engine as claimed in claim 15, wherein the propulsor is selected from a group consisting essentially of a fan and a propeller.

17. A gas turbine engine as claimed in claim 1, wherein

the gas turbine engine comprises a low-pressure turbine, a static structure, and a propulsor;

the sun gear is driven by the low-pressure turbine;

the annulus gear is secured to the static structure; and

the carrier is arranged to drive the propulsor.

18. A gas turbine engine as claimed in claim 1, wherein

the gas turbine engine comprises a low-pressure turbine, a static structure, and a propulsor;

the sun gear is driven by the low-pressure turbine;

the carrier is secured to the static structure; and

the annulus gear is arranged to drive the propulsor.

19. A gearbox comprising:

a sun gear;

an annulus gear;

a plurality of planet gears; and

a carrier,

the sun gear meshing with the planet gears and the planet gears meshing with the annulus gear;

the carrier comprising a first ring, a second ring spaced axially from the first ring, and a plurality of circumferentially spaced axles extending axially between the first ring and the second ring;

each planet gear being rotatably mounted on a respective one of the plurality of circumferentially spaced axles, each of the plurality of circumferentially spaced axles being arranged at a first radius; and

at least one of the first ring and the second ring comprising a metal matrix composite material, the metal matrix composite material comprising a ring of reinforcing fibres, and the ring of reinforcing fibres having a second radius greater than the first radius.

20. A planet gear carrier comprising:

a first ring;

a second ring spaced axially from the first ring;

a plurality of circumferentially spaced axles extending axially between the first ring and the second ring; and

a plurality of planet gears,

each planet gear being rotatably mounted on a respective one of the plurality of circumferentially spaced axles, each of the plurality of circumferentially spaced axles being arranged at a first radius; and

at least one of the first ring and the second ring comprising a metal matrix composite material, the metal matrix composite material comprising a ring of reinforcing fibres, and the ring of reinforcing fibres having a second radius greater than the first radius.