# US 8,771,786 B2 · Method for repair of a component of a turbomachine and a component repaired according to this method

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- Number: US 8,771,786 B2
- Document ID: US8771786B2
- Status: Granted
- Kind: B2
- Application number: 13/713,799
- Filed: 2012-12-13
- Published: 2013-07-04
- Granted: 2014-07-08
- Earliest claimed: 2011-12-15
- Assignees: MTU Aero Engines AG
- Applicants: MTU Aero Engines GmbH
- Inventors: Michael Raiche; Christian Heinzelmaier
- Web page: https://patentgrep.com/patent/US8771786B2

## CPC

- B05D 5/005: {Repairing damaged coatings}
- B23P 6/007: {using only additive methods, e.g. build-up welding}
- F01D 5/005: {Repairing methods or devices}
- F01D 5/027: {Arrangements for balancing (for balancing rotating bodies in general F16F15/32; for compensating imbalance G01M1/36)}
- F01D 21/045: {special arrangements in stators or in rotors dealing with breaking-off of part of rotor}
- F05D 2240/80: Platforms for stationary or moving blades
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)
- B23P: METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS (arrangements for copying or controlling B23Q)
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A method is disclosed for the repair of a component of a turbomachine, in particular a rotor of an aircraft gas turbine, with blades taken up in at least one groove and with at least one support region for limiting a blade tilt angle, whereby at least one segment, which has been subjected to wear, of the support region of the component is removed, and a coating that can be introduced in the unit on at least one supporting surface of at least one blade is formed on the component for limiting the blade tilt angle. In addition, a component of a turbomachine, in particular a rotor of an aircraft gas turbine, with at least one such repair site is disclosed.

## Claims

### Claim 1

A method for the repair of a rotor of an aircraft gas turbine, with blades (8) taken up in at least one groove (6) and with at least one support region (26) for blades (8) for limiting a blade tilt angle α, comprising the steps of:
providing a rotor having at least one annular groove, the at least one annular groove having side walls,
removing at least one segment (28), which has been subjected to wear, of a first support region (26) adjacent to the annular groove, and
forming a coating (38) that can be introduced in the unit on at least one supporting surface (36) of a second support region for engaging at least one blade (8) for limiting the blade tilt angle α, the coating forming a bearing surface on the at least one supporting surface, wherein the bearing surface limits the blade tilt angle α more than the supporting surface would without the coating applied thereon.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the at least one segment (28) of the first support region (26), which is disposed under a blade platform (14) of blade (8) is removed.

### Claim 3 (depends on 2)

The method according to claim 2, wherein a coating (38) is introduced on at least one region of rotor (4) facing the blade platform (14) and forms a bearing surface (42), which can be introduced in the unit with the supporting surface (36) of the blade platform (14) for limiting the blade tilt angle α.

### Claim 4 (depends on 1)

The method according to claim 1, with a rotor formed as a compressor rotor (4) and blades formed as compressor blades (8), wherein each at least one annular groove (18) is configured for the uptake of a ring element (16), in particular a damping and/or retaining ring, and wherein the at least one segment, which has been subjected to wear, forms a portion of a side wall (22) of the annular groove and is removed.

### Claim 5 (depends on 4)

The method according to claim 4, wherein the coating (38) is introduced onto a second side wall (20) of the annular groove (18) disposed on an opposite side of the annular groove from the side wall (22).

### Claim 6 (depends on 5)

The method according to claim 5, wherein the coating (38) is introduced onto a radially outer peripheral surface (40) of the second side wall (20), with respect to the center of the rotor.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the coating (38) is introduced onto a region that preferably extends along a periphery of the rotor over a length L1 that at least corresponds to the length L2 of the removed segment (28).

### Claim 8 (depends on 1)

The method according to claim 1, wherein the coating (38) is introduced by spraying.

### Claim 9 (depends on 1)

The method according to claim 1, wherein a notching (30) and/or rounding out is formed by means of the removal of the segment (28).