Shaft assembly

Patent metadata

Field	Value
Publication number	US-10907476-B2
Application number	US-201916374778-A
Country	US
Kind code	B2
Filing date	Apr 4, 2019
Priority date	Apr 20, 2018
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

A shaft assembly for a gas turbine engine is provided. The shaft assembly comprises: a first shaft having an outer surface; a first coupling ring disposed around the outer surface of the first shaft, an inner surface of the first coupling ring being coupled to the outer surface of the first shaft; a second shaft having an inner surface; and a second coupling ring disposed around the inner surface of the second shaft, an outer surface of the second coupling ring being coupled to the inner surface of the second shaft, wherein an outer surface of the first coupling ring is configured to mate with an inner surface of the second coupling ring, such that concentricity of the first and second shafts is maintained at the shaft assembly by virtue of the mating of the first and second coupling rings. Methods of assembling and re-assembling a shaft assembly are also provided.

First claim

The invention claimed is:

1. A shaft assembly for a gas turbine engine, the shaft assembly comprising:
a first shaft having an outer surface and an axial abutment face;
a first coupling ring having an axial end face, the first coupling ring disposed around the outer surface of the first shaft, an inner surface of the first coupling ring being coupled to the outer surface of the first shaft;
a second shaft having an inner surface; and
a second coupling ring having an axial end face, the second coupling ring disposed around the inner surface of the second shaft, an outer surface of the second coupling ring being coupled to the inner surface of the second shaft, wherein an outer surface of the first coupling ring is configured to mate with an inner surface of the second coupling ring, such that concentricity of the first and second shafts is maintained at the shaft assembly by virtue of the mating of the first and second coupling rings;
wherein one or both of the axial end face of the first coupling ring and the axial end face of the second coupling ring are configured to abut the axial abutment face of the first shaft when the first coupling ring and the second coupling ring mate,
wherein the first coupling ring and the second coupling ring are configured to form an interference fit between one another when mated together.

2. The shaft assembly of claim 1 , wherein the axial end face of the first coupling ring is a first axial end face of the first coupling ring and the axial end face of the second coupling ring is a first axial end face of the second coupling ring, the first coupling ring having a second axial end face and the second coupling ring having a second axial end face, wherein the second shaft comprises an axial abutment face, wherein one or both of the second axial end face of the first coupling ring and the second axial end face of the second coupling ring abut the axial abutment face of the second shaft when the first and second coupling rings mate.

3. The shaft assembly of claim 1 , wherein the outer surface of the first coupling ring and the inner surface of the second coupling ring are conical, such that a shape of the inner surface of the second coupling ring corresponds to a shape of the outer surface of the first coupling ring.

4. The shaft assembly of claim 1 , wherein the outer surface of the first coupling ring and the inner surface of the second coupling ring are hardened surfaces.

5. The shaft assembly of claim 1 , wherein the inner surface of the second coupling ring is harder than the outer surface of the first coupling ring.

6. The shaft assembly of claim 1 , wherein one or more of the first and the second shafts comprise an axial groove aligned with the first and second coupling rings respectively.

7. The shaft assembly of claim 1 , further comprising an axial retainer configured to retain the first and second shafts relative to one another in an axial direction.

8. The shaft assembly of claim 1 , wherein the first shaft comprises a rotor shaft for a gas turbine engine and the second shaft comprises a rotor shaft, a blade disc or a bladed disc for a gas turbine engine.

9. A shaft assembly for a gas turbine engine, the shaft assembly comprising;
a first shaft having an outer surface;
a second shaft having an inner surface, wherein a portion of the first shaft is received inside of the inner surface of the second shaft;
an expandable coupling ring disposed around the outer surface of the first shaft and arranged between the outer surface of the first shaft and the inner surface of the second shaft, wherein the expandable coupling ring is configured to selectively expand in a radial direction in order to couple to the first and second shafts together such that concentricity of the first and second shafts is maintained at the shaft assembly by the expandable coupling ring,
wherein an outer surface of the expandable coupling ring mates with the inner surface of the second shaft when expanded.

10. The shaft assembly of claim 9 , wherein the shaft assembly further comprises an axial retainer configured to apply an axial force to the expandable coupling ring, wherein the expandable coupling ring is configured to expand in the radial direction under an action of the axial force.

11. A method of assembling a shaft assembly, the shaft assembly comprising:
a first shaft having an outer surface;
a second shaft having an inner surface, wherein the method comprises:
coupling an inner surface of a first coupling ring to the outer surface of the first shaft such that the first coupling ring is disposed around the outer surface of the first shaft;
coupling an outer surface of a second coupling ring to the inner surface of the second shaft such that the second coupling ring is disposed around the inner surface of the second shaft, wherein one or more of the first shaft and the second shaft comprise an axial groove aligned with the first coupling ring and the second coupling ring respectively; and
mating an outer surface of the first coupling ring with an inner surface of the second coupling ring such that concentricity of the first and second shafts is maintained at the shaft assembly.

12. The method of claim 11 , wherein the outer surface of the first coupling ring and the inner surface of the second coupling ring are conical, such that the inner surface of the second coupling ring corresponds to the outer surface of the first coupling ring, wherein the step of mating the outer surface of the first coupling ring with the inner surface of the second coupling ring comprises:
displacing the first and second shafts relative to one another in an axial direction.

13. A method of re-assembling a shaft assembly, wherein the shaft assembly comprises:
a first shaft having an outer surface;
a first coupling ring disposed around the outer surface of the first shaft, wherein an inner surface of the first coupling ring is coupled to the outer surface of the first shaft;
a second shaft having an inner surface; and
a second coupling ring disposed around the inner surface of the second shaft, wherein an outer surface of the second coupling ring is coupled to the inner surface of the second shaft, and wherein an outer surface of the first coupling ring is mated with an inner surface of the second coupling ring to form a joint between the first and second shafts, wherein the method comprises:
disconnecting the joint between the first and second shafts by bringing the outer surface of the first coupling ring out of contact with the inner surface of the second coupling ring;
replacing one or both of the first coupling ring and the second coupling ring; and
reconnecting the first and second shafts such that the outer surface of the first coupling ring is mated with the inner surface of the second coupling ring.

14. The method of claim 13 , wherein one or more of the first and the second shafts comprise an axial groove aligned with the first and second coupling rings, wherein the step of replacing one or both of the first coupling ring and the second coupling ring comprises cutting through the first and second coupling rings being replaced, and wherein a cutting tool used to cut through the one or more of the first and second coupling rings passes though the axial groove during the cutting operation.

15. A gas turbine engine for an aircraft comprising:
an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor;
a fan located upstream of the engine core, the fan comprising a plurality of fan blades; and
a gearbox that receives an input from the core shaft and o

Assignees

• Rolls Royce Plc

Inventors

• Cooper Joseph B

Classifications

• F16D1/05

  with radial clamping due to axial loading of at least one pair of conical surfaces · CPC title

• F01D5/026 Primary

  Shaft to shaft connections · CPC title

• F05D2250/232

  conical · CPC title

• F05D2230/64

  using positioning or alignment devices for aligning or centring, e.g. pins · CPC title

• F05D2240/60

  Shafts · CPC title