Electric enhanced transmission for multi-spool load-sharing turbofan engine

Patent metadata

Field	Value
Publication number	US-2020240331-A1
Application number	US-201916261688-A
Country	US
Kind code	A1
Filing date	Jan 30, 2019
Priority date	Jan 30, 2019
Publication date	Jul 30, 2020
Grant date	—

Abstract

A turbofan engine includes a first spool including a first turbine, and a first tower shaft engaged to the first spool. A second spool includes a second turbine, and a second tower shaft is engaged to the second spool. A superposition gearbox includes a sun gear, a plurality of intermediate gears engaged to the sun gear, and is supported in a carrier and a ring gear circumscribing the intermediate gears. The first tower shaft or the second tower shaft drives one of the intermediate gears. A drive motor is engaged to drive the sun gear, an inner electric motor, a stator disposed radially outside of the inner electric motor, and an outer electric motor disposed radially outside the stator. A first load on the first spool and a second load on the second spool is adjusted by operation of at least one of the inner electric motor and the outer electric motor.

First claim

What is claimed is:

1 . A turbofan engine comprising:
a first spool including a first turbine; a first tower shaft engaged to the first spool; a second spool including a second turbine; a second tower shaft engaged to the second spool; a superposition gearbox including a sun gear, a plurality of intermediate gears engaged to the sun gear and supported in a carrier and a ring gear circumscribing the intermediate gears, wherein one of the first tower shaft or the second tower shaft drives one of the intermediate gears; a drive motor engaged to drive the sun gear; an inner electric motor; a stator disposed radially outside of the inner electric motor; and an outer electric motor disposed radially outside the stator, wherein a first load on the first spool and a second load on the second spool is adjusted by operation of at least one of the inner electric motor and the outer electric motor.

2 . The turbofan engine as recited in claim 1 , wherein the carrier is fixed to a static structure of the turbofan engine.

3 . The turbofan engine as recited in claim 2 , wherein the first tower shaft and the second tower shaft are disposed within a common radial plane.

4 . The turbofan engine as recited as claim 1 , wherein the stator is fixed to the static structure of the turbofan engine.

5 . The turbofan engine as recited in claim 4 , wherein the first tower shaft is engaged to drive the inner electric motor and the ring gear is engaged to drive the outer electric motor.

6 . The turbofan engine as recited in claim 4 , wherein the second tower shaft is engaged to drive the inner electric motor and the ring gear is engaged to drive the outer electric motor.

7 . The turbofan engine as recited in claim 1 , wherein first spool includes a first compressor section coupled to a first turbine section, the first tower shaft and the second tower shaft are disposed forward of the first compressor section.

8 . The turbofan engine as recited in claim 7 , wherein the second spool includes a second compressor section that is disposed forward of the first tower shaft and the second tower shaft.

9 . The turbofan engine as recited in claim 1 , including a controller in electric communication with the drive motor, the inner electric motor and the outer electric motor for proportioning the first load and the second load between the first spool and the second spool by controlling a speed of the drive motor and a stator field of the inner electric motor and the outer electric motor.

10 . A turbofan engine comprising:
a first spool including a first turbine; a second spool including a second turbine; a superposition gearbox disposed about an axis and including a sun gear, a plurality of intermediate gears engaged to the sun gear and supported in a carrier and a ring gear circumscribing the intermediate gears; a drive means engaged to drive the sun gear; an integrated motor generator disposed about the axis and including an inner armature and an outer armature rotatable relative to a fixed stator disposed radially between the inner armature and the outer armature, wherein one of the inner armature and the outer armature is mechanically coupled to the first spool and the other of the inner armature and the outer armature is coupled to a portion of the superposition gearbox and a first load on the first spool and a second load on the second spool is adjusted by modification of stator fields of the inner armature and the outer armature.

11 . The turbofan engine as recited in claim 10 , wherein the carrier is fixed to the static structure of the turbofan engine.

12 . The turbofan engine as recited in claim 11 , including a first tower shaft engaged to be driven by the first spool and a second tower shaft engaged to be driven by the second spool, wherein the one of the first tower shaft and the second tower shaft drive one of the intermediate gears and the other of the first tower shaft and the second tower shaft drive one of the inner armature or the outer armature.

13 . The turbofan engine as recited in claim 12 , wherein the drive means comprises an electric motor.

14 . The turbofan engine as recited in claim 13 , including a controller in electric communication with the drive motor and the integrated motor generator for proportioning the first load and the second load between the first spool and the second spool by controlling a speed of the drive motor and stator fields of the inner armature and the outer armature.

15 . A method of proportioning a load between spools of a turbofan engine comprising:
coupling an intermediate gear of a superposition gearbox to a first spool, wherein the superposition gearbox includes a sun gear, a plurality of intermediate gears and a ring gear circumscribing the plurality of the intermediate gears; coupling a first portion of an integrated motor generator to a second spool; coupling a second portion of the integrated motor generator to the superposition gearbox; coupling the sun gear to a drive means; and controlling a speed of the sun gear with the drive means; and controlling a stator field of the integrated motor generator to proportion a load between the first spool and the second spool.

16 . The method as recited in claim 15 , including driving the first spool with the integrated motor/generator for starting the turbofan engine.

17 . The method as recited in claim 16 , including fixing the carrier to a static structure of the turbofan engine and the drive means comprises an electric motor driving the sun gear of the superposition gearbox.

18 . The method as recited in claim 15 , wherein the integrated motor generator includes an inner armature and an outer armature disposed between a fixed stator and controlling a load between the first spool and the second spool includes adjusting a stator field between each of the inner armature and the outer armature.

Assignees

• United Technologies Corp

Inventors

• Kupratis Daniel Bernard
• Wood Coy Bruce

Classifications

• H02K16/02

  Machines with one stator and two {or more} rotors · CPC title

• F02C7/32 Primary

  Arrangement, mounting, or driving, of auxiliaries · CPC title

• F02C7/275

  Mechanical drives · CPC title

• F02C7/36 Primary

  Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user ({F02C3/107 - F02C3/13 and} F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H) · CPC title

• F16H3/727

  with at least two dynamo electric machines for creating an electric power path inside the gearing, e.g. using generator and motor for a variable power torque path · CPC title