Hybrid electric propulsion with superposition gearbox

Patent metadata

Field	Value
Publication number	US-2020158213-A1
Application number	US-201816197605-A
Country	US
Kind code	A1
Filing date	Nov 21, 2018
Priority date	Nov 21, 2018
Publication date	May 21, 2020
Grant date	—

Abstract

A gas turbine engine includes a core engine, a fan section, and a superposition gearbox that includes a sun gear. A plurality of intermediate gears are engaged to the sun gear and supported in a carrier and a ring gear circumscribing the intermediate gears. The core engine drives the sun gear and an output from the superposition gearbox driving the fan section. An electric motor is coupled to a portion of the superposition gearbox to provide a portion of power to drive the fan section through the superposition gearbox.

First claim

What is claimed is:

1 . A gas turbine engine comprising:
a core engine; a fan section; 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, the core engine driving the sun gear and an output from the superposition gearbox driving the fan section; and an electric motor coupled to a portion of the superposition gearbox to provide a portion of power to drive the fan section through the superposition gearbox.

2 . The gas turbine engine as recited in claim 1 , wherein the ring gear includes inner gear teeth engaged to the intermediate gears and outer gear teeth engaged to a drive gear driven by the electric motor.

3 . The gas turbine engine as recited in claim 2 , wherein the drive gear is supported on a drive shaft driven by the electric motor and the drive shaft is separate and independent of a core engine shaft driving the sun gear.

4 . The gas turbine engine as recited in claim 2 , including a one-way clutch automatically coupling the ring gear to a static structure of the gas turbine engine when the electric motor is not actuated.

5 . The gas turbine engine as recited in claim 3 , wherein the one-way clutch comprises a one-way mechanical sprag clutch.

6 . The gas turbine engine as recited in claim 1 , wherein the fan section includes a shaft driven by the carrier of the superposition gearbox.

7 . The gas turbine engine as recited in claim 1 , wherein the electric motor is coupled to a battery system and the core engine drives a generator for charging the battery system.

8 . The gas turbine engine as recited in claim 1 , wherein a sea level takeoff thrust is provided by power generated by the core engine and the electric motor.

9 . The gas turbine engine as recited in claim 8 , wherein the core engine includes a maximum thrust capacity that is less than the sea level takeoff thrust.

10 . The gas turbine engine as recited in claim 9 , wherein the electric motor is deactivated such that only the core engine provides thrust at a cruise operating condition.

11 . A gas turbine engine comprising:
a core engine including a compressor section configured to communicate compressed air to a combustor section configured to combine the compressed air with fuel and ignite the combined air and fuel to generate a high energy gas flow for driving a turbine section, the turbine section configured to drive a turbine shaft disposed along an engine longitudinal axis; a fan section configured to generate a propulsive thrust, the fan section including a shaft; 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, the turbine shaft configured to drive the sun gear and an output from the superposition gearbox configured to drive the shaft; an electric motor coupled to a portion of the superposition gearbox to provide supplemental power to drive the fan section through the superposition gearbox; and a coupling means configured to automatically couple a portion of the superposition gearbox to static structure when the electric motor is not driving the portion of the superposition gearbox.

12 . The gas turbine engine as recited in claim 11 , wherein the ring gear includes inner gear teeth engaged to the intermediate gears and outer gear teeth engaged to a gear system driven by the electric motor.

13 . The gas turbine engine as recited in claim 12 , wherein the drive gear driven by the electric motor is independent of the turbine shaft and separately rotatable at a speed different than the turbine shaft and the coupling means comprises a one-way mechanical sprag clutch.

14 . The gas turbine engine as recited in claim 11 , wherein a sea level takeoff thrust is provided by power generated by the core engine and the electric motor and wherein the core engine includes a maximum thrust capacity that is less than the sea level takeoff thrust.

15 . A method of operating a gas turbine engine comprising:
coupling a core engine to a first portion of a superposition gearbox; coupling an electric motor to a second portion of a superposition gearbox; driving a fan through the superposition gearbox with power from both the core engine and the electric motor to generate a takeoff thrust; and driving the fan through the superposition gearbox with power from only the core engine during a cruise operating condition.

16 . The method as recited in claim 15 , wherein the first portion of the superposition gearbox comprises a sun gear engaged to drive a plurality of intermediate gears and the second portion comprises a ring gear circumscribing the intermediate gears and the method further includes coupling the ring gear to a static structure of the gas turbine engine responsive to the electric motor not driving the ring gear.

17 . The method as recited in claim 16 , including actuating the electric motor to drive the ring gear and provide supplemental power in response to a desired engine thrust exceeding a thrust generating capacity of the core engine alone.

18 . The method as recited in claim 17 , including charging a battery system providing power to the electric motor with the core engine during the cruise operating condition.

Assignees

• United Technologies Corp

Inventors

• Leque Nicholas D
• Mccune Michael E
• Polly Joseph H

Classifications

• F16H3/724 Primary

  using externally powered electric machines · CPC title

• F05D2240/60

  Shafts · CPC title

• F05D2220/32

  in gas turbines · CPC title

• F02C7/36

  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

• F05D2260/40311

  of the epicyclical, planetary or differential type · CPC title