Flexible support structure for a geared architecture gas turbine engine

• US 8,297,916 B1
• Filed: 01/03/2012
• Issued: 10/30/2012
• Est. Priority Date: 06/08/2011
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: McCune, Michael E., Husband, Jason
• Primary Examiner(s): Nguyen, Ninh H
• Assistant Examiner(s): MCDOWELL, LIAM J
• Application Number:
  US13/342,508
• Time in Patent Office: 301 Days
• Field of Search: 602/23, 602/261, 415/9, 415/68, 415/122.1, 415/124.2, 415/119, 415/124.1, 416/500, 700/280
• US Class Current: 415/124.1
• CPC Class Codes: F01D 15/12 Combinations with mechanical gearing driven by multiple engines F01D13/00
• CPC Class Codes: F01D 25/164 Flexible supports; Vibration damping means associated with the bearing
• CPC Class Codes: F02C 7/20 Mounting or supporting of plant; Accommodating heat expansion or creep
• 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 2260/40311 of the epicyclical, planetary or differential type
• CPC Class Codes: F05D 2260/96 Preventing, counteracting or reducing vibration or noise
• CPC Class Codes: F05D 2300/501 Elasticity
• CPC Class Codes: F16H 1/48 Special means compensating for misalignment of axes , e.g. for equalising distribution of load on the face width of the teeth in combination with distribution of load on the planet-wheels F16H1/2809

Abstract

A geared architecture with a flex mount for a Fan Drive Gear System defined by a lateral stiffness relationship.

Claims

1. A geared architecture for a gas turbine engine comprising:

a fan shaft;

a frame which supports said fan shaft, said frame defines a frame lateral stiffness;

a gear system which drives said fan shaft;

a flexible support which at least partially supports said gear system, said flexible support defines a flexible support lateral stiffness with respect to said frame lateral stiffness; and

an input coupling to said gear system, said input coupling defines an input coupling lateral stiffness with respect to said frame lateral stiffness.

2. The geared architecture as recited in claim 1, wherein said frame and said flexible support are mounted to a static structure.

3. The geared architecture as recited in claim 1, wherein said frame and said flexible support are mounted to a static structure of a gas turbine engine.

4. The geared architecture as recited in claim 1, wherein said frame and said flexible support are mounted to a front center body of a gas turbine engine.

5. The geared architecture as recited in claim 1, wherein said flexible support is mounted to a planet carrier of said gear system.

6. The geared architecture as recited in claim 5, wherein said input coupling is mounted to a sun gear of said gear system.

7. The geared architecture as recited in claim 6, wherein said fan shaft is mounted to a ring gear of said gear system.

8. The geared architecture as recited in claim 7, wherein said gear system is a star system.

9. The geared architecture as recited in claim 1, wherein said flexible support is mounted to a ring gear of said gear system.

10. The geared architecture as recited in claim 9, wherein said input coupling is mounted to a sun gear of said gear system.

11. The geared architecture as recited in claim 10, wherein said fan shaft is mounted to a planet carrier of said gear system.

12. The geared architecture as recited in claim 11, wherein said gear system is a planet system.

13. The geared architecture as recited in claim 1, further comprising a low speed spool which drives said input coupling.

14. The geared architecture as recited in claim 1, wherein at least one of said flexible support lateral stiffness and said input coupling lateral stiffness are less than about 20% of said frame lateral stiffness.

15. The geared architecture as recited in claim 1, wherein said flexible support lateral stiffness and said input coupling lateral stiffness are each less than about 20% of said frame lateral stiffness.

16. The geared architecture as recited in claim 1, wherein at least one of said flexible support lateral stiffness and said input coupling lateral stiffness are less than about 11% of said frame lateral stiffness.

17. The geared architecture as recited in claim 1, wherein said flexible support lateral stiffness and said input coupling lateral stiffness are each less than about 11% of said frame lateral stiffness.

18. The geared architecture as recited in claim 1, wherein said frame which supports said fan shaft and defines said frame lateral stiffness is a K-frame bearing support, said K-frame bearing support supporting a bearing system that supports said fan shaft.

19. A geared architecture for a gas turbine engine comprising:

a fan shaft;

a frame which supports said fan shaft;

a gear system which drives said fan shaft, said gear system includes a gear mesh that defines a gear mesh;

a flexible support which at least partially supports said gear system, said flexible support defines a flexible support lateral stiffness with respect to said gear mesh lateral stiffness; and

an input coupling to said gear system, said input coupling defines an input coupling lateral stiffness with respect to said gear mesh lateral stiffness.

20. The geared architecture as recited in claim 19, wherein said flexible support lateral stiffness is less than about 8% of said gear mesh lateral stiffness.

21. The geared architecture as recited in claim 19, wherein said input coupling lateral stiffness is less than about 5% of said gear mesh lateral stiffness.

22. The geared architecture as recited in claim 19, wherein a lateral stiffness of a ring gear of said gear system is less than about 20% of said gear mesh lateral stiffness.

23. The geared architecture as recited in claim 19, wherein a lateral stiffness of a ring gear of said gear system is less than about 12% of said gear mesh lateral stiffness.

24. The geared architecture as recited in claim 19, wherein a lateral stiffness of a planet journal bearing which supports a planet gear of said gear system is less than or equal to said gear mesh lateral stiffness.

25. The geared architecture as recited in claim 19, wherein said gear mesh lateral stiffness (KGM) is defined between a sun gear and a multiple planet gears of said gear system.

26. The geared architecture as recited in claim 19, wherein said gear system floats with said fan shaft.

27. The geared architecture as recited in claim 19, wherein a planet journal bearing which supports a planet gear of said gear system defines a lateral stiffness with respect to said gear mesh lateral stiffness.

28. The geared architecture as recited in claim 19, wherein a ring gear of said gear system defines a lateral stiffness with respect to said gear mesh lateral stiffness.