Mitigation of effects of fan blade off in a gas turbine engine

Patent metadata

Field	Value
Publication number	US-10677089-B2
Application number	US-201815933423-A
Country	US
Kind code	B2
Filing date	Mar 23, 2018
Priority date	Mar 29, 2017
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

A fan is mounted on a fan shaft which constitutes part of a mainline shaft assembly centered for rotation on an engine axis X-X of a gas turbine engine. When in operation, the fan rotates about the engine axis X-X. A stub-shaft is arranged radially outwardly and concentrically with the fan shaft and adjoins an upstream facing face of a bearing sleeve. A fan catcher arm extends from the stub-shaft through the bearing sleeve and joins a fan catcher ring arranged downstream of the bearing sleeve and having an upstream facing face arranged to abut against a downstream facing face of the bearing sleeve in the event of a fan blade-off. Immediately downstream of the fan catcher ring is formed a shaft end which is configured to couple with an axially adjacent end of a low pressure compressor shaft. Immediately downstream of the bearing sleeve is a shaft end configured to connect with a turbine shaft.

First claim

The invention claimed is:

1. A gas turbine engine comprising;
a fan mounted for rotation on a fan shaft having an axis of rotation X-X,
a stub shaft coaxially arranged with the fan shaft, radially facing surfaces of the stub shaft and fan shaft engaging each other at an end adjacent the fan,
a fan catcher assembly comprising one or more fan catcher arms extending from the stub shaft to a fan catcher ring located axially downstream of the fan,
the stub-shaft connected to an upstream facing face of a bearing housing and the fan catcher ring having an upstream facing face opposing a downstream facing face of the bearing housing,
the catcher arm and fan shaft extending through a central aperture of the bearing housing,
wherein,
in an extended region from a position upstream of an upstream facing face of the bearing housing to a position downstream of the upstream facing face of the bearing housing, a radial gap between the fan catcher arm and the fan shaft is consistently less than 5 mm.

2. A gas turbine engine as claimed in claim 1 wherein the extended region extends from the stub shaft.

3. A gas turbine engine as claimed in claim 1 wherein the extended region terminates at a downstream end at a position which is closer to the upstream facing face of the bearing housing than to the downstream facing face of the bearing housing.

4. A gas turbine engine as claimed in claim 1 wherein the radial gap is minimised such that, in the event of unbalance in the fan, the fan shaft and fan catcher arm deflect together as if a single body.

5. A gas turbine engine as claimed in claim 1 wherein the radial gap is 4mm or less.

6. A gas turbine engine as claimed in claim 1 wherein the radial gap is 3 mm or less.

7. A gas turbine engine as claimed in claim 1 wherein the radial gap is 2 mm or less.

8. A gas turbine engine as claimed in claim 1 wherein the radial gap is 1 mm or less.

9. A gas turbine engine as claimed in claim 1 wherein complementary contours are provided on opposed radially facing walls of the fan shaft and fan catcher arm in the extended region.

10. A gas turbine engine as claimed in claim 1 wherein the thickness of the fan shaft in a radial dimension is increased in the extended region compared to outside of the extended region.

Assignees

• Rolls Royce Plc

Inventors

• Lucey Kieran P
• Bendall Stephen J

Classifications

• F02C7/06

  Arrangements of bearings (bearings F16C); Lubricating ({of turbo machines F01D25/18; of machines or} engines in general F01M) · CPC title

• F05D2240/60

  Shafts · CPC title

• F04D29/044

  Arrangements for joining or assembling shafts · CPC title

• F01D21/045 Primary

  special arrangements in stators or in rotors dealing with breaking-off of part of rotor · CPC title

• F01D5/026

  Shaft to shaft connections · CPC title