MID-TURBINE FRAME ASSEMBLY

• US 20190316491A1
• Filed: 05/30/2019
• Published: 10/17/2019
• Est. Priority Date: 02/03/2015
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: Winn, Joshua Daniel, Broulidakis, Alexander, Sanchez, Paul K., Cherolis, Anthony P., Sedor, Joseph J., Treat, Christopher
• Granted Patent: US 10,961,870 B2
• Time in Patent Office: Days
• CPC Class Codes: F01D 25/12 Cooling
• CPC Class Codes: F01D 25/162 Bearing supports
• CPC Class Codes: F01D 25/26 Double casings; Measures against temperature strain in casings
• CPC Class Codes: F01D 25/28 Supporting or mounting arrangements, e.g. for turbine casing
• CPC Class Codes: F01D 5/02 Blade-carrying members, e.g. rotors rotors of non-bladed type F01D1/34; stators F01D9/00 ; selecting particular materials F01D5/28
• CPC Class Codes: F01D 9/065 Fluid supply or removal conduits traversing the working fluid flow, e.g. for lubrication-, cooling-, or sealing fluids see also F01D25/16, F01D25/24 and F01D25/26
• CPC Class Codes: F02C 7/12 Cooling of plants of component parts, see the relevant subclasses, e.g. F01D; cooling of engines in general F01P
• CPC Class Codes: F05D 2220/32 in gas turbines
• CPC Class Codes: F05D 2220/3213 an intermediate stage of the turbine
• CPC Class Codes: F05D 2240/24 for turbines
• CPC Class Codes: F05D 2260/20 Heat transfer, e.g. cooling
• CPC Class Codes: F05D 2260/31 Retaining bolts or nuts
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A method of cooling a portion of a gas turbine engine includes positioning a tie rod relative to an inner frame case. The tie rod includes a bushing opening and the inner frame case includes a fastener opening. A fastener is secured through the fastener opening in the inner frame case to a threaded bushing located in the bushing opening. The threaded bushing includes a distal end that forms a clearance gap with the inner frame case. Heat is transferred from the fastener through the threaded bushing to prevent the fastener from creeping.

Claims

1. A method of cooling a portion of a gas turbine engine comprising:

positioning a tie rod relative to an inner frame case, wherein the tie rod includes a bushing opening and the inner frame case includes a fastener opening;

securing a fastener through the fastener opening in the inner frame case to a threaded bushing located in the bushing opening, wherein the threaded bushing includes a distal end that forms a clearance gap with the inner frame case; and

transferring heat from the fastener through the threaded bushing to prevent the fastener from creeping.

2. The method of claim 1, wherein the tie rod is made of a first material and the bushing is made of a second dissimilar material.

3. The method of claim 1, wherein the tie rod includes a tie rod flange and a projecting portion.

4. The method of claim 3, wherein the projecting portion extends upward from an upper surface of the tie rod flange.

5. The method of claim 4, wherein the projecting portion at least partially defines an inlet passage through the tie rod.

6. The method of claim 1, further comprising shielding the fastener from radiant heat exposure by recessing the fastener in the threaded bushing.

7. The method of claim 3, wherein the bushing opening includes a first axial length and the bushing includes a cylindrical portion having a second axial length, with the first axial length greater than the second axial length to at least partially define the clearance gap.

8. The method of claim 7, wherein the second axial length is between 80% and 95% of the first axial length.

9. The method of claim 1, further comprising preventing the threaded bushing from rotating relative to the tie rod with a tab on a bushing flange engaging a portion of the tie rod.

10. The method of claim 9, wherein the tab engages a projecting portion that extends upward from an upper surface of a flange on the tie rod.

11. The method of claim 9, wherein the tab includes an edge having a radius that is larger than a radius of an edge of the bushing flange opposite the tab.

12. The method of claim 1, further comprising maintaining a roundness of a mid-turbine frame in the gas turbine engine with transferring the heat from the fastener to the threaded bushing.

13. A method of assembling a portion of a gas turbine engine comprising:

positioning a tie rod relative to an inner frame case, wherein the tie rod includes a tie rod flange having a bushing opening and the inner frame case includes a fastener opening aligned with the bushing opening;

securing a fastener to a threaded bushing located in the bushing opening; and

preventing rotation of the threaded bushing relative to the tie rod with a tab on a bushing flange engaging a portion of the tie rod, wherein the tab includes an edge having a radius that is larger than a radius of an edge of the bushing flange opposite the tab.

14. The method of claim 13, wherein the tie rod is made of a first material and the bushing is made of a second dissimilar material.

15. The method of claim 13, wherein a projecting portion extends upward from an upper surface of the tie rod flange.

16. The method of claim 15, wherein the projecting portion at least partially defines an inlet passage through the tie rod.

17. The method of claim 13, wherein the bushing opening includes a first axial length and the bushing includes a cylindrical portion having a second axial length, with the first axial length greater than the second axial length to at least partially define a clearance gap between the threaded bushing and the inner frame case.

18. The method of claim 17, wherein the second axial length is between 80% and 95% of the first axial length.

19. The method of claim 17, wherein the second axial length extends from a flange on the threaded bushing to a distal end surface.

20. The method of claim 13, further comprising shielding the fastener from radiant heat exposure by recessing the fastener in the threaded bushing.