Power transmission arrangement

• US 7,698,884 B2
• Filed: 08/12/2008
• Issued: 04/20/2010
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: Edwards, David A., Richards, Martyn, Knight, Glenn A., Butt, David C., Kirk, Geoffrey E., Maguire, Alan R.
• Primary Examiner(s): KIM, TAE JUN
• Application Number:
  US12/222,551
• Publication Number:
  US 20080302082A1
• Time in Patent Office: 616 Days
• Field of Search: 60/391.63, 60786-788, 74D/IG.5
• US Class Current: 60/39.163
• CPC Class Codes: F02C 3/107 with two or more rotors connected by power transmission
• CPC Class Codes: F02C 7/268 Starting drives for the rotor , acting directly on the rotor of the gas turbine to be started
• CPC Class Codes: F02C 7/27 Fluid drives turbine starters F02C7/277
• CPC Class Codes: F02C 7/275 Mechanical drives
• 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: Y10S 74/05 Gas turbine with gearing

Abstract

A power transmission arrangement comprises a first power transmission member connectable to a first main shaft of an engine. The arrangement also includes a second power transmission member connectable to a second main shaft of the engine and to a third power transmission member. A coupling assembly is provided which has a selectable coupling condition to couple the first power transmission member to the second power transmission member to allow power to be transmitted from the third power transmission member to the first main shaft of the engine via the first power transmission member. The coupling assembly has a decoupling condition to decouple the first power transmission member from the second power transmission member to allow power to be transmitted from the main shaft of the engine to the third power transmission member via the second power transmission member.

Claims

1. A power transmission arrangement for a gas turbine engine having in axial flow series a first stage compressor, a second stage compressor, a first stage turbine and a second stage turbine, a first main shaft connecting the first stage turbine to the second stage compressor so that the first stage turbine drives the second stage compressor during operation of the engine, and a second main shaft connecting the second stage turbine to the first stage compressor so that the second stage turbine drives the first stage compressor during operation of the engine, said power transmission arrangement comprising:

a first power transmission member connectable to the first main shaft;

a second power transmission member connectable to the second main shaft;

a third power transmission member; and

a coupling assembly having a selectable coupling condition to couple the first power transmission member to the second power transmission member to allow power to be transmitted from the third power transmission member to the first main shaft via the first power transmission member, and having a selectable decoupling condition to decouple the first power transmission member from the second power transmission member to allow power to be transmitted from the second main shaft to the third transmission member via the second transmission member.

2. A power transmission arrangement according to claim 1 wherein the coupling assembly is mounted on the first and second power transmission members.

3. A power transmission arrangement according to claim 1 wherein the coupling assembly comprises a fluid operated clutch.

4. A power transmission arrangement according to claim 1 wherein the coupling assembly comprises a main body having first and second parts movable relative to each other.

5. A power transmission arrangement according to claim 4 wherein the second power transmission member comprises a connection member to drivingly connect the third power transmission member thereto.

6. A power transmission arrangement according to claim 5 wherein the connection member comprises a gear to drivingly connect the third power transmission member to the second transmission member.

7. A power transmission arrangement according to claim 5 wherein the second power transmission member extends through the main body to said connection member.

8. A power transmission arrangement according to claim 4 wherein the first part comprises a first fluid chamber, and the second part comprises a second fluid chamber, the first and second parts being in fluid communication with each other.

9. A power transmission arrangement according to claim 8 wherein each of the first and second fluid chambers is of an annular configuration.

10. A power transmission arrangement according to claim 9 wherein each of the first and second fluid chambers is of a toroidal configuration.

11. A power transmission arrangement according to claim 9 wherein the main body has a configuration of a torus defining a space to receive at least one of said first and second power transmission members.

12. A power transmission arrangement according to claim 11 wherein the space receives both of said first and second power transmission members and the second power transmission member extends wholly through the aforesaid space.

13. A power transmission arrangement according to claim 8 wherein each of the chambers includes a plurality of radially extending vanes.

14. A power transmission arrangement according to claim 8 wherein the coupling assembly comprises an enclosure in which the main body is arranged, and fluid from the main body can drain into the enclosure.

15. A power transmission arrangement according to claim 8 wherein the coupling assembly comprises a fluid supply system to supply fluid to the main body.

16. A power transmission arrangement according to claim 15 wherein the fluid supply system is arranged to supply fluid to the main body via the central member extending into, or through, said central space.

17. A power transmission arrangement according to claim 15 wherein the fluid supply system is arranged to supply to the main body externally of the central space.

18. A power transmission arrangement according to claim 17 wherein the fluid supply is supplied through one or more fluid supply holes in the main body.

19. A power transmission arrangement according to claim 4 wherein the main body includes drain means to allow fluid in the main body to drain there from.

20. A power transmission arrangement according to claim 19 wherein the drain means comprises a drain aperture or a plurality of drain apertures defined in the main body, the, or each, drain aperture being defined in a region between the first and second chambers.

21. A power transmission arrangement according to claim 4 wherein the first part is fixedly mounted on the first power transmission member, and the second part is fixedly mounted on the second power transmission member.

22. A power transmission arrangement according to claim 1 wherein the first and second power transmission members comprise shafts, arranged coaxially relative to each other.

23. A power transmission arrangement according to claim 22 wherein the second power transmission member is arranged within the first power transmission member.

24. A power transmission arrangement according to claim 1 wherein the coupling assembly is offset from the first and second power transmission member and Is connected to the first and second power transmission members by at least one ancillary gear arrangement.

25. A power transmission arrangement according to claim 1, wherein the first main shaft is connected to the first power transmission member, and the second main shaft is connected to the second power transmission member.

26. A power transmission arrangement according to claim 25 further including a starter for starting the drive arrangement, wherein the power transmission arrangement can couple together the first and second power transmission members during starting, whereby the starter can turn both of the first and second main shafts during the aforesaid starting of the drive arrangement, and can decouple the first and second main shafts after the aforesaid starting to permit independent operation of the first and second main shafts.

27. A power transmission arrangement according to claim 26 wherein the starter is connected to the third power transmission member.

28. A power transmission arrangement according to claim 1 including power receiving means connected to the third power transmission member and the second main shaft drives the power receiving means after decoupling of the first and second main shafts from each other.

29. A power transmission arrangement for a gas turbine engine, said gas turbine engine comprising:

an intermediate pressure compressor;

a high pressure compressor;

a high pressure turbine;

an intermediate pressure turbine;

a first main shaft connecting said high pressure compressor and said high pressure turbine;

a second main shaft connecting said intermediate pressure compressor and said intermediate pressure turbine; and

a power transmission arrangement arranged between said intermediate compressor and said high pressure compressor, said power transmission comprising;

a coupling assembly;

a first power transmission shaft connected to said first main shaft;

a second power transmission shaft connected to said second main shaft; and

a third power transmission member, wherein said second power transmission shaft is arranged within said first power transmission shaft, and wherein said first and second power transmission shafts are selectively coupled to, and decoupled from, each other by said coupling assembly to allow power to be transmitted from the third power transmission member via the power transmission arrangement to the first main shaft when the first and second power transmission shafts are selectively coupled and to allow power to be transmitted to the third power transmission member via the power transmission arrangement from the second main shaft when the first and second power transmission shafts are selectively decoupled.

30. A power transmission arrangement according to claim 29, wherein said coupling assembly comprising a main body defining a central space, a fluid supply means, a first annular chamber having a plurality of radially extending first vanes, and a second annular chamber having a plurality of radially extending second vanes wherein said coupling assembly has a selectable coupling condition to couple said first power transmission shaft to said second power transmission shaft in which power is transmitted from said third power transmission member to said first main shaft via said first power transmission shaft, and wherein said coupling assembly has a selectable decoupling condition to decouple said first power transmission shaft and said second power transmission shaft to allow said first main shaft and said second main shaft to turn independently of each other.

31. A power transmission arrangement according to claim 29, wherein said coupling assembly comprising a friction clutch.

32. A power transmission arrangement according to claim 31, wherein said friction clutch comprising:

a driven clutch plate mounted on said first power transmission shaft;

a driving clutch plate slidably mounted on said second power transmission shaft;

a piston arrangement and a thrust bearing, said piston arrangement comprising an annular piston holder and a piston wherein said annular piston holder defines a first chamber and a second chamber, and wherein said piston comprises a separator fixedly connected to an annular axially extending piston member such that said separator extends into said annular piston holder to separate said first and second chambers from each other;

a first fluid supply line for supplying hydraulic fluid to said first chamber; and

a second fluid supply line for supplying hydraulic fluid to said second chamber wherein said coupling assembly has a selectable coupling condition in which said driving clutch plate engages said driven clutch plate to couple said first power transmission shaft to said second power transmission shaft, and wherein said coupling assembly has a selectable decoupling condition in which said driving clutch plate becomes disengaged from said driven clutch plate to decouple said first power transmission shaft and said second power transmission shaft.

33. A power transmission arrangement according to claim 29, wherein said coupling assembly comprising a fluid clutch.

34. A power transmission arrangement according to claim 33, wherein said fluid clutch comprising:

a driven clutch plate mounted on said first power transmission shaft;

a driving clutch plate slidably mounted on said second power transmission shaft;

a spring arrangement and a reaction plate wherein said reaction plate extends radially from said second power transmission shaft, said spring arrangement surrounding said second power transmission shaft and biasing the driving clutch towards said driven clutch;

a housing comprising an axially extending annular wall member and an inwardly extending wall member such that said reaction plate, said axially extending wall member and said inwardly extending wall member define a chamber wherein said second power transmission shaft defines a plurality of radially extending feed holes which extend through said second power transmission shaft to feed oil into said chamber; and

a split ring provided within said chamber which, during operation of said engine, prevents said driven clutch plate and said driving clutch plate from re-engaging each other if the supply of oil into said chamber should fail.

35. A power transmission arrangement according to claim 29, wherein said coupling assembly comprising a planetary gear arrangement.

36. A power transmission arrangement according to claim 35, wherein said planetary gear arrangement comprising:

a primary sun gear fixedly mounted on said second power transmission shaft;

a secondary sun gear fixedly mounted on said first power transmission shaft;

a plurality of primary planetary gears wherein each primary planetary gear is in meshing engagement with said primary sun gear;

a plurality of secondary planetary gears wherein each secondary planetary gear is in meshing engagement with said secondary sun gear, and wherein the primary and secondary planetary gears are co-axial with one another;

an annular carrier located between said primary and said secondary planetary gears; and

a brake having a braking position in which the brake engages said carrier to prevent rotation of said carrier and said primary and secondary planetary gears, and wherein said brake is in said braking position when said first and second power transmission shafts are coupled to each other such that rotation of said second power transmission shaft is transmitted via said planetary gear arrangement to said first power transmission shaft.

37. A power transmission arrangement according to claim 29, wherein said first and second power transmission shafts extend radially relative to said main shaft and said second main shaft.

38. A power transmission arrangement according to claim 37, wherein said gas turbine engine comprises an engine control unit and said first and second power transmission shafts terminate in said coupling assembly, wherein said coupling assembly comprises:

a plurality of springs;

a plurality of ratchets provided around a circumference of said first power transmission shaft;

at least three pawls provided on the interior of said second power transmission shaft, wherein said pawls are urged by said springs onto said ratchets;

speed sensors provided in said coupling assembly to detect respective speeds of said first and second power transmission shafts; and

a gear arrangement provided towards an end of said second power transmission shaft to connect said second main shaft to said third power transmission member such that, during use, said first power transmission shaft rotates at a greater speed than said second power transmission shaft which causes said ratchets to move past said pawls, and wherein, during use, said engine control unit switches from acting as a starter to a generator, and wherein said generator will be powered by said second power transmission shaft via said gear arrangement and said third power transmission member.

39. A power transmission arrangement according to claim 29, wherein said coupling assembly comprises a first annular chamber and a second annular chamber.

40. A power transmission arrangement according to claim 39, wherein said coupling assembly is offset from said first and second power transmission shafts.

41. A power transmission arrangement according to claim 39, wherein said third power transmission member is directly connected to said second annular chamber.

42. A power transmission arrangement according to claim 41, wherein said third power transmission member is connected by a gear arrangement to said second power transmission shaft.

43. A power transmission arrangement according to claim 39, wherein said first power transmission shaft is connected to said first annular chamber by a first ancillary gear arrangement and an ancillary shaft, wherein said ancillary shaft is mounted directly on said first annular chamber.