Air turbine starter with seal assembly

• US 6,318,958 B1
• Filed: 08/09/1999
• Issued: 11/20/2001
• Est. Priority Date: 08/21/1998
• Status: Expired due to Fees

• Current Assignee: Alliedsignal Inc.
• Original Assignee: Alliedsignal Inc.
• Inventors: Moy, Jack, Alten, Charles Jon, Geck, Kellan, Giesler, William Lee
• Primary Examiner(s): VERDIER, CHRISTOPHER M
• Application Number:
  US09/370,675
• Time in Patent Office: 834 Days
• Field of Search: 415/110, 415/111, 415/168.1, 415/168.2, 415/173.5, 415/174.2, 415/174.3, 415/174.5, 415/124.1, 415/122.1, 415/170.1, 415/112, 415/113, 415/123, 415/174.4, 415/230, 415/231, 606/25, 606/26, 277/348, 277/352, 277/390, 277/412, 277/415
• US Class Current: 415/112
• CPC Class Codes: F01D 11/00 Preventing or minimising internal leakage of working-fluid, e.g. between stages sealings in general F16J ; sealing arrangements for transition ducts of combustor cans F01D9/023
• CPC Class Codes: F02C 7/277 the starter being a separate turbine

Abstract

An air turbine starter with an improved seal assembly disposed between the turbine and the housing is provided. The seal assembly comprises a face seal, a non-contacting seal axially spaced therefrom to define an air filled annular chamber therebetween and a flow passage having an exit fluidly communicating with said chamber and an inlet fluidly communicating with a source of air.

Claims

1. An air turbine starter comprising:

a housing defining an inlet, an outlet, and a flow path communicating said inlet with said outlet for conveying a flow of pressurized air therebetween;

a turbine disposed in said flow path and having a turbine shaft extending therefrom journaled for rotation to said housing by at least one lubricated bearing, said turbine converting the pressure energy of said pressurized air to shaft power;

an output shaft journaled by said housing for transmitting said shaft power externally of said starter;

a gear train coupling said turbine with said output shaft, said gear train including a one-way overrunning clutch transmitting torque to said output shaft and preventing back driving from said output shaft to said geartrain; and

a seal assembly disposed between said lubricated bearing and said turbine wheel, said assembly comprising a face seal and a labyrinth seal axially spaced therefrom to define an air filled annular chamber therebetween;

said labyrinth seal extending radially inward from said housing to a radially inner tip having at least one knife edge that seals against a radially outward facing surface of said turbine shaft.

2. The air turbine starter of claim 1, wherein said inner tip has an abradeable contact zone.

3. The air turbine starter of claim 1, wherein said inner tip has a non-abradeable contact zone.

4. An air turbine starter comprising:

a housing defining an inlet, an outlet, and a flow path communicating said inlet with said outlet for conveying a flow of pressurized air therebetween;

a turbine disposed in said flow path and having a turbine shaft extending therefrom journaled for rotation to said housing by at least one lubricated bearing, said turbine converting the pressure energy of said pressurized air to shaft power;

an output shaft journaled by said housing for transmitting said shaft power externally of said starter;

a gear train coupling said turbine with said output shaft, said gear train including a one-way overrunning clutch transmitting torque to said output shaft and preventing back driving from said output shaft to said geartrain;

a seal assembly disposed between said lubricated bearing and said turbine wheel, said assembly comprising a face seal and a non-contacting seal axially spaced therefrom to define an air filled annular chamber therebetween; and

a flow passage having an exit fluidly communicating with said chamber and an inlet fluidly communicating with a source of air.

5. The air turbine starter of claim 4 wherein said flow passage inlet is a hole in said housing.

6. The air turbine starter of claim 4 wherein said flow passage inlet fluidly communicates with a turbine exhaust duct in said air turbine starter.

7. The air turbine starter of claim 4 wherein said flow passage inlet fluidly communicates to where said starter is externally coupled.

8. The air turbine starter of claim 4 wherein said flow passage inlet fluidly communicates with a duct delivering pressurized air to said turbine.

9. The air turbine starter of claim 4 wherein said flow passage has a reduction orifice.

10. The air turbine starter of claim 4 wherein said flow passage comprises tubing.

11. The air turbine starter of claim 4 wherein said flow passage is comprised of cast-in passages.

21. The air turbine starter of claim 4 wherein the non-contacting seal is one of a knife labyrinth, a lip seal, a floating ring seal, a short static bushing, a long static bushing, a contacting piston ring, a brush seal, or a face seal.

12. An air turbine starter comprising:

a housing defining an inlet, an outlet, and a flow path communicating said inlet with said outlet for conveying a flow of pressurized air therebetween;

a turbine disposed in said flow path and having a turbine shaft extending therefrom journaled for rotation to said housing by at least one lubricated bearing, said turbine converting the pressure energy of said pressurized air to shaft power;

an output shaft journaled by said housing for transmitting said shaft power externally of said starter;

a gear train coupling said turbine with said output shaft, said gear train including a one-way overrunning clutch transmitting torque to said output shaft and preventing back driving from said output shaft to said geartrain; and

a seal assembly disposed between said lubricated bearing and said turbine wheel, said assembly comprising a face seal, a non-contacting seal axially spaced therefrom to define an air filled annular chamber therebetween and a flow passage having an exit fluidly communicating with said chamber and an inlet fluidly communicating with a source of air.

13. The air turbine starter of claim 12 wherein the flow area of the flow passage is at least three times larger than the flow area of said non-contacting seal.

14. The air turbine starter of claim 13 wherein said non-contacting seal is a labyrinth seal with at least one knife edge.

15. The air turbine starter of claim 14 wherein said face seal comprises a rotor mounted to said turbine shaft and having an axially facing flange, a stator mounted to said housing;

and a carbon ring seal mounted to said stator for sealingly engaging said axially facing flange.

22. The air turbine starter of claim of 12 wherein the non-contacting seal is one of a knife labyrinth, a lip seal, a floating ring seal, a short static bushing, a long static bushing, a contacting piston ring, a brush seal, or a face seal.

23. The air turbine starter of claim 15 wherein said face seal is positioned adjacent said lubricated bearing.

16. A seal assembly for sealing between a rotating member and a stationary housing comprising:

a face seal having a rotor mounted to said rotating member and a stator mounted to said housing; and

a labyrinth seal extending radially inwardly from said housing to a radially inner tip having at least one knife edge that seals against a radially outward facing surface of said rotating member, said labyrinth seal axially spaced from said face seal to define an annular chamber therebetween.

17. The seal assembly of claim 16 wherein said inner tip has an abradeable contact zone.

18. The seal assembly of claim 16 wherein said inner tip has a non-abradeable contact zone.

19. The seal assembly of claim 16 wherein said chamber is filled with air.

20. The seal assembly of claim 19 further comprising a flow passage for delivering said air to said chamber.