MID TURBINE FRAME (MTF) FOR A GAS TURBINE ENGINE

• US 20130094951A1
• Filed: 10/17/2011
• Published: 04/18/2013
• Est. Priority Date: 10/17/2011
• Status: Active Grant

• Current Assignee: Raytheon Technologies Corporation d/b/a RTX
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: McCaffrey, Michael G.
• Granted Patent: US 9,200,536 B2
• Time in Patent Office: Days
• US Class Current: 415/200
• CPC Class Codes: F01D 25/162 Bearing supports
• CPC Class Codes: F01D 25/246 Fastening of diaphragms or stator-rings
• CPC Class Codes: F01D 9/041 using blades F01D5/148 takes precedence
• CPC Class Codes: F05D 2220/32 in gas turbines
• CPC Class Codes: F05D 2240/15 Heat shield
• CPC Class Codes: F05D 2300/20 Oxide or non-oxide ceramics
• CPC Class Codes: F05D 2300/6033 Ceramic matrix composites [CMC]
• CPC Class Codes: Y10T 29/49337 Composite blade

Abstract

A static structure of a gas turbine engine according to an exemplary aspect of the present disclosure includes a multiple of airfoil sections between an outer ring and an inner ring. A spring biased tie-rod assembly is mounted through at least one of the multiple of airfoil sections.

Claims

1. A static case structure for a gas turbine engine comprising:

an outer ring;

an inner ring;

a multiple of airfoils between said outer ring and said inner ring; and

a spring biased tie-rod assembly mounted through at least one of said multiple of airfoils.

2. The static case structure as recited in claim 1, wherein said static case structure is a mid-turbine frame for a gas turbine engine.

3. The static case structure as recited in claim 2, wherein said multiple of airfoils, said outer ring and said inner ring define a ring-strut-ring structure.

4. The static case structure as recited in claim 2, wherein said multiple of airfoils, said outer ring and said inner ring define a unitary structure.

5. The static case structure as recited in claim 2, further comprising a support tie-rod fastened to an annular inner turbine exhaust case and an annular outer turbine exhaust case, said support tie-rod mounted through at least one of said multiple of airfoils.

6. The static case structure as recited in claim 1, wherein said outer ring and said inner ring are manufactured of a multiple of Ceramic Matrix Composite (CMC) plies defined around an axis.

7. The static case structure as recited in claim 6, wherein said axis is a longitudinal axis of the gas turbine engine.

8. The static case structure as recited in claim 1, wherein said multiple of airfoils, said outer ring and said inner ring are manufactured of a Ceramic Matrix Composite (CMC), which form a unitary structure.

9. A mid-turbine frame for a gas turbine engine comprising:

a CMC outer ring;

a CMC inner ring;

a multiple of CMC airfoils between said CMC outer ring and said CMC inner ring; and

a spring biased (preloaded) tie-rod assembly mounted through at least one of said multiple of CMC airfoils.

10. The mid-turbine frame as recited in claim 9, wherein at least one of said multiple of CMC airfoils includes a pressure vessel.

11. The mid-turbine frame as recited in claim 10, wherein said pressure vessel is adjacent to said spring biased tie-rod assembly within an airfoil section.

12. The mid-turbine frame as recited in claim 9, wherein at least one of said multiple of CMC airfoils includes a split ring insert, said split ring spring biased tie-rod assembly mounted through said insert.

13. The mid-turbine frame as recited in claim 12, wherein said insert is located within a leading edge of said at least one of said multiple of CMC airfoils.

14. The mid-turbine frame as recited in claim 9, further comprising a support tie-rod fastened to an annular inner turbine exhaust case and an annular outer turbine exhaust case, said support tie-rod mounted through at least one of said multiple of CMC airfoils.

15. The mid-turbine frame as recited in claim 9, wherein said spring biased tie-rod assembly includes a tie rod manufactured of a monolithic ceramic material.

16. The mid-turbine frame as recited in claim 15, wherein said tie rod includes a flared end section.

17. The mid-turbine frame as recited in claim 16, wherein said flared end section is frustro-conical.

18. The mid-turbine frame as recited in claim 9, wherein said spring preloaded tie-rod assembly includes a tie rod manufactured of a ceramic matrix composite material.

19. The mid-turbine frame as recited in claim 18, wherein said tie rod includes a flared end section.

20. The mid-turbine frame as recited in claim 19, wherein said flared end section is frustro-conical.

21. The mid-turbine frame as recited in claim 20, wherein said flared end section is a combination of monolithic ceramic and ceramic matrix composite materials.

22. A method of assembling a mid-turbine frame for a gas turbine engine comprising:

bonding a multiple of CMC airfoils between a CMC outer ring and a CMC inner ring; and

spring biasing a tie-rod assembly mounted through at least one of the multiple of CMC airfoils to maintain a tie rod in tension and at least a portion of the multiple of CMC airfoils, the CMC outer ring and the CMC inner ring in compression.

23. The method as recited in claim 22, further comprising:

bonding a multiple of CMC airfoils between a CMC outer ring and a CMC inner ring as a unitary annular structure.