Trunnion hole repair method utilizing interference fit inserts

Patent metadata

Field	Value
Publication number	US-9943932-B2
Application number	US-201615131235-A
Country	US
Kind code	B2
Filing date	Apr 18, 2016
Priority date	Apr 9, 2008
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

The present application discloses a method for repairing a damaged counterbore in a variable vane shroud. A layer of base material is removed from the vane shroud adjacent the counterbore such that a damaged portion of the counterbore is removed. A shrink-fit insert having a size slightly larger than that corresponding to the layer of base material removed from the shroud is placed into the area of removed material such that the counterbore is restored to pre-damaged dimensions upon installation of the shrink-fit insert.

First claim

The invention claimed is:

1. A method for repairing a damaged counterbore in a variable vane shroud, the method comprising:
removing a layer of base material from the vane shroud adjacent to the counterbore such that a damaged portion of the counterbore is removed;
supercooling an insert prior to installation, the shroud having a size slightly larger than that corresponding to the layer of base material removed from the shroud; and
placing the insert into the area of removed material such that the counterbore is restored to pre-damaged dimensions upon installation of the insert.

2. The method of claim 1 wherein the step of removing the layer of base material comprises machining the counterbore.

3. The method of claim 1 wherein the layer of removed base material comprises removing a cylindrically shaped portion of the base material.

4. The method of claim 1 wherein the insert has outer dimensions that create an interference fit with the counterbore.

5. The method of claim 1 wherein the insert is a pre-existing part.

6. The method of claim 1 where in the insert is a custom made part.

7. The method of claim 1 wherein supercooling the insert further comprises:
placing the insert in liquid nitrogen.

8. The method of claim 1 further comprising:
securing the supercooled insert in place.

9. The method of claim 8 wherein securing the insert is done with a threaded fastener and washers.

10. The method of claim 1 wherein the insert contains tangs on an outer perimeter to secure the insert in place with respect to the shroud.

11. The method of claim 1 wherein the insert is comprised of a material having a lower coefficient of friction than the base material of the vane shroud.

12. The method of claim 11 wherein the insert comprises at least one of the following materials: a metallic alloy and a plastic.

13. A method for repairing a damaged variable vane shroud, the method comprising:
removing a layer of base material from the vane shroud adjacent to a counterbore such that a damaged portion of the counterbore is removed;
measuring the amount of material removed;
creating an insert based on the measurements of the amount of removed material;
supercooling the insert; and
installing the insert adjacent the vane shroud, wherein the insert returns the vane shroud to its design parameters.

14. The method of claim 13 wherein installing the insert comprises:
securing the insert with a threaded fastener and washers.

15. The method of claim 13 wherein the insert has outer dimensions that creates an interference fit with the counterbore.

16. The method of claim 13 wherein supercooling the insert further comprises:
placing the insert in liquid nitrogen.

Assignees

• United Technologies Corp

Inventors

• Addis Mark E
• Reynolds George H

Classifications

• B23P11/025

  by using heat or cold · CPC title

• Y10T29/49865

  by temperature differential [e.g., shrink fit] · CPC title

• F05D2220/32

  in gas turbines · CPC title

• Y10T29/49726

  Removing material · CPC title

• Y10T29/49318

  Repairing or disassembling · CPC title