Geared gas turbine engine

Patent metadata

Field	Value
Publication number	US-12297779-B2
Application number	US-202418433932-A
Country	US
Kind code	B2
Filing date	Feb 6, 2024
Priority date	Dec 5, 2019
Publication date	May 13, 2025
Grant date	May 13, 2025

Abstract

Gas turbine engine for aircraft includes: an engine core including a turbine, compressor, and core shaft connecting the turbine to the compressor; a fan located upstream of the core; a gearbox; and a gearbox support arranged to at least partially support the gearbox. The fan has a mass in a range of 150 kg to 1200 kg. A moment of inertia of the fan is greater than or equal to 7.40×10 7 kgmm 2 . A radial bending stiffness to moment of inertia ratio of:
the ⁢ radial ⁢ bending ⁢ stiffness ⁢ of ⁢ at ⁢ least ⁢ one ⁢ of ⁢ the ⁢ fan ⁢ shaft ⁢ at ⁢ the ⁢ output ⁢ of ⁢ the ⁢ gearbox ⁢ and ⁢ the ⁢ gearbox ⁢ support the ⁢ moment ⁢ of ⁢ inertia ⁢ of ⁢ the ⁢ fan
may be greater than or equal to 2.5×10 −2 Nkg −1 m −1 mm −2 . A tilt stiffness to moment of inertia ratio of:

the ⁢ tilt ⁢ stiffness ⁢ of ⁢ at ⁢ least ⁢ one ⁢ of ⁢ the ⁢ fan ⁢ shaft ⁢ at ⁢ the ⁢ output ⁢ of ⁢ the ⁢ gearbox ⁢ and ⁢ the ⁢ gearbox ⁢ support the ⁢ moment ⁢ of ⁢ inertia ⁢ of ⁢ the ⁢ fan
may be greater than or equal to 4.0×10 −4 Nmrad −1 kg −1 mm −2 .

First claim

The invention claimed is:

1. 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;
a gearbox that is configured to receive an input from the core shaft, and output drive to a fan shaft via an output of the gearbox so as to drive the fan at a lower rotational speed than the core shaft, the gearbox being an epicyclic gearbox comprising a sun gear, a plurality of planet gears, a ring gear, and a planet carrier arranged to have the plurality of planet gears mounted thereon; and
a gearbox support arranged to at least partially support the gearbox within the engine,
wherein:
a moment of inertia of the fan is in a range from 7.40×10 7 kgmm 2 to 9.00×10 8 kgmm 2 ;
at least one radial bending stiffness to moment of inertia ratio selected from the group consisting of:
a first ratio of:

a
⁢

radial
⁢

bending
⁢

stiffness
⁢

of
⁢

the
⁢

fan
⁢

shaft
⁢

at
⁢

the
⁢

output
⁢

of
⁢

the
⁢

gearbox

the
⁢

moment
⁢

of
⁢

inertia
⁢

of
⁢

the
⁢

fan

,
and

a second ratio of:

a
⁢

radial
⁢

bending
⁢

stiffness
⁢

of
⁢

the
⁢

gearbox
⁢

support

the
⁢

moment
⁢

of
⁢

inertia
⁢

of
⁢

the
⁢

fan

is in a range from 2.5×10 −2 Nkg −1 m −1 mm −2 to 6.0 Nkg −1 m −1 mm −2 , and
the fan has a mass in a range of 150 kg to 1200 kg.

2. The gas turbine engine according to claim 1 , wherein the at least one radial bending stiffness to moment of inertia ratio is in a range from 0.05 Nkg −1 m −1 mm −2 to 3.0 Nkg −1 m −1 mm −2 .

3. The gas turbine engine according to claim 1 , wherein:
a) the first ratio of the radial bending stiffness of the fan shaft at the output of the gearbox to the moment of inertia of the fan is in a range from 0.05 Nkg −1 m −1 mm −2 to 3.0 Nkg −1 m −1 mm −2 ; and/or
b) the second ratio of the radial bending stiffness of the gearbox support to the moment of inertia of the fan is in a range from 3.0×10 −2 Nkg −1 m −1 mm −2 to 4.0 Nkg −1 m −1 mm −2 .

4. The gas turbine engine according to claim 1 , wherein:
a) the radial bending stiffness of the fan shaft at the output of the gearbox is in a range from 3.7×10 7 N/m to 1.0×10 9 N/m; and/or
b) the radial bending stiffness of the gearbox support is in a range from 2.0×10 7 N/m to 3.0×10 8 N/m.

5. The gas turbine engine according to claim 1 , wherein:
a) a diameter of the fan is in a range from 240 cm to 280 cm, and the at least one radial bending stiffness to moment of inertia ratio is in a range from 0.05 Nkg −1 m −1 mm −2 to 4.0 Nkg −1 m −1 mm −2 ; or
b) the diameter of the fan is in a range from 330 cm to 380 cm and the at least one radial bending stiffness to moment of inertia ratio is in a range from 0.025 Nkg −1 m −1 mm −2 to 2.0 Nkg −1 m −1 mm −2 .

6. The gas turbine engine according to claim 1 , wherein at least one product selected from the group consisting of:
a first product of:
(the radial bending stiffness of the fan shaft at the output of the gearbox)×(the moment of inertia of the fan), and

a second product of:
(the radial bending stiffness of the gearbox support)×(the moment of inertia of the fan)

is in a range from 2.0×10 14 Nkgmm 2 m −1 to 1.4×10 18 Nkgmm 2 m −1 .

7. The gas turbine engine according to claim 1 , wherein at least one tilt stiffness to moment of inertia ratio selected from the group consisting of:
a first tilt stiffness ratio of:

a
⁢

tilt
⁢

stiffness
⁢

of
⁢

the
⁢

fan
⁢

shaft
⁢

at
⁢

the
⁢

output
⁢

of
⁢

the
⁢

gearbox

the
⁢

moment
⁢

of
⁢

inertia
⁢

of
⁢

the
⁢

fan

,
and

a second tilt stiffness ratio of:

a
⁢

tilt
⁢

stiffness
⁢

Assignees

• Rolls Royce Plc

Inventors

• Spruce Mark

Classifications

• F02C3/107

  with two or more rotors connected by power transmission · CPC title

• F16H2057/02043

  for vehicle transmissions · CPC title

• F16H57/08

  of gearings with members having orbital motion · CPC title

• F16H57/025

  Support of gearboxes, e.g. torque arms, or attachment to other devices · CPC title

• F05D2260/40311

  of the epicyclical, planetary or differential type · CPC title