# US 2023/0399983 A1 · Differential gearbox assembly for a turbine engine

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- Number: US 2023/0399983 A1
- Document ID: US20230399983A1
- Status: Published application
- Kind: A1
- Application number: 17/806,574
- Filed: 2022-06-13
- Published: 2023-12-14
- Earliest claimed: 2022-06-13
- Assignees: General Electric Company; GE Avio S.r.l.
- Applicants: General Electric Company; GE Avio S.r.l.
- Inventors: Ravindra Shankar Ganiger; Andrea Piazza; Gontla Nagashiresha; Bugra H. Ertas; Sanjeev Jha
- Web page: https://patentgrep.com/patent/US20230399983A1

## CPC

- F02C 7/36: 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)
- F01D 15/10: Adaptations for driving, or combinations with, electric generators
- F02C 3/113: with variable power transmission between rotors
- F02K 3/06: with front fan
- F05D 2220/768: equipped with permanent magnets
- F05D 2260/40311: of the epicyclical, planetary or differential type
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

A differential gearbox assembly for a turbine engine having a fan shaft and a drive shaft. The differential gearbox assembly includes an epicyclic gear assembly coupling the fan shaft to the drive shaft. The epicyclic gear assembly includes a sun gear, a planet gear constrained by a planet carrier, and a ring gear. The sun gear is coupled to the drive shaft and the planet carrier is coupled to the fan shaft. The sun gear, the planet gear, and the ring gear all rotate about the drive shaft. The differential gearbox assembly includes an electric machine assembly that includes an input coupled to the epicyclic gear assembly. The electric machine assembly provides mechanical power to the fan shaft through the epicyclic gear assembly.

## Claims

### Claim 1

A differential gearbox assembly for a turbine engine having a fan shaft, a drive shaft, and a booster having a plurality of variable stator vanes and a plurality of blades coupled to a booster shaft, the differential gearbox assembly comprising:
an epicyclic gear assembly coupling the fan shaft to the drive shaft and coupling the booster shaft to the drive shaft through the epicyclic gear assembly, the epicyclic gear assembly including a sun gear, a planet gear constrained by a planet carrier, and a ring gear, the sun gear coupled to the drive shaft, the planet carrier coupled to the fan shaft, and the ring gear coupled to the booster shaft, wherein the sun gear, the planet gear, and the ring gear all rotate about the drive shaft, and the drive shaft provides mechanical power to the fan shaft and to the booster shaft through the epicyclic gear assembly; and
an electric machine assembly comprising an input coupled to the epicyclic gear assembly, the electric machine assembly providing mechanical power to the fan shaft through the epicyclic gear assembly, wherein the electric machine assembly includes an electric motor and an electric generator for generating electric power, the electric motor providing additional mechanical power to the fan shaft during operation of the turbine engine, and at least a portion of the mechanical power from the drive shaft is provided to the electric generator when mechanical power to the fan shaft is reduced such that the electric generator generates electric power from the epicyclic gear assembly, and the plurality of variable stator vanes are actuated to change an incidence angle of the plurality of variable stator vanes to change an air flow to the plurality of blades of the booster such that a speed of the ring gear remains constant while the electric motor provides the additional mechanical power to the fan shaft.

### Claim 2 (depends on 1)

The differential gearbox assembly of claim 1, wherein the differential gearbox assembly splits a torque between the booster shaft and the electric machine assembly.

### Claim 3 (depends on 1)

The differential gearbox assembly of claim 1, wherein the electric motor drives at least one gear of the epicyclic gear assembly.

### Claim 4 (depends on 1)

The differential gearbox assembly of claim 1, wherein the input of the electric machine assembly is coupled to the planet carrier, and the electric machine assembly drives the planet carrier to provide mechanical power to the fan shaft.

### Claim 5 (depends on 1)

The differential gearbox assembly of claim 1, wherein the electric machine assembly is an annular drive system such that the electric machine assembly is annular about the drive shaft.

### Claim 6 (depends on 1)

The differential gearbox assembly of claim 1, wherein the electric machine assembly is a compact drive system.

### Claim 7

(canceled)

### Claim 8 (depends on 1)

The differential gearbox assembly of claim 1, wherein the electric motor provides mechanical power to the fan shaft through the differential gearbox assembly in a first operating mode of the turbine engine, and the electric generator generates the electric power in a second operating mode of the turbine engine.

### Claim 9 (depends on 1)

The differential gearbox assembly of claim 1, wherein the input of the electric machine assembly is coupled to the ring gear, and the electric machine assembly drives the ring gear to provide mechanical power to the fan shaft.

### Claim 10 (depends on 9)

The differential gearbox assembly of claim 9, wherein the electric machine assembly comprises:
a stator connected to a static component of the differential gearbox assembly; and
a rotor that includes one or more permanent magnets on the ring gear.

### Claim 11

A turbine engine comprising:
a turbine including a drive shaft;
a fan including a fan shaft;
a booster including a booster shaft, a plurality of variable stator vanes, and a plurality of blades coupled to the booster shaft; and
a differential gearbox assembly comprising:
an epicyclic gear assembly coupling the fan shaft to the drive shaft and coupling the booster shaft to the drive shaft through the epicyclic gear assembly, the epicyclic gear assembly including a sun gear, a planet gear constrained by a planet carrier, and a ring gear, the sun gear coupled to the drive shaft and the planet carrier coupled to the fan shaft, and the ring gear coupled to the booster shaft, wherein the sun gear, the planet gear, and the ring gear all rotate about the drive shaft, and the drive shaft provides mechanical power to the fan shaft and to the booster shaft through the epicyclic gear assembly; and
an electric machine assembly comprising an input coupled to the epicyclic gear assembly, the electric machine assembly providing mechanical power to the fan through the epicyclic gear assembly, wherein the electric machine assembly includes an electric motor and an electric generator for generating electric power, the electric motor providing additional mechanical power to the fan shaft during operation of the turbine engine, and at least a portion of the mechanical power from the drive shaft is provided to the electric generator when mechanical power to the fan shaft is reduced such that the electric generator generates electric power from the epicyclic gear assembly and the plurality of variable stator vanes are actuated to change an incidence angle of the plurality of variable stator vanes to change an air flow to the plurality of blades of the booster such that a speed of the ring gear remains constant while the electric motor provides the additional mechanical power to the fan shaft.

### Claim 12 (depends on 11)

The turbine engine of claim 11, wherein the differential gearbox assembly splits a torque between the booster shaft and the electric machine assembly.

### Claim 13 (depends on 11)

The turbine engine of claim 11, wherein the electric motor drives at least one gear of the epicyclic gear.

### Claim 14 (depends on 11)

The turbine engine of claim 11, wherein the input of the electric machine assembly is coupled to the planet carrier, and the electric machine assembly drives the planet carrier to provide mechanical power to the fan shaft.

### Claim 15 (depends on 11)

The turbine engine of claim 11, wherein the electric machine assembly is an annular drive system such that the electric machine assembly is annular about the drive shaft.

### Claim 16 (depends on 11)

The turbine engine of claim 11, wherein the electric machine assembly is a compact drive system.

### Claim 17

(canceled)

### Claim 18 (depends on 11)

The turbine engine of claim 11, wherein the electric motor provides mechanical power to the fan shaft through the differential gearbox assembly in a first operating mode of the turbine engine, and the electric generator generates the electric power in a second operating mode of the turbine engine.

### Claim 19 (depends on 11)

The turbine engine of claim 11, wherein the input of the electric machine assembly is coupled to the ring gear, and the electric machine assembly drives the ring gear to provide mechanical power to the fan shaft.

### Claim 20 (depends on 19)

The turbine engine of claim 19, wherein the electric machine assembly comprises a stator connected to a static component of the differential gearbox assembly and a rotor that includes one or more permanent magnets on the ring gear.

### Claim 21 (depends on 1)

The differential gearbox assembly of claim 1, wherein the plurality of variable stator vanes are actuated to change the incidence angle of the plurality of variable stator vanes to reduce mechanical power to the booster shaft such that the electric generator generates electric power from the epicyclic gear assembly.

### Claim 22 (depends on 8)

The differential gearbox assembly of claim 8, wherein the first operating mode and the second operating mode include at least one of a takeoff flight mode, a climb flight mode, a cruise flight mode, a step change flight mode, a descent flight mode, a landing flight mode, or a taxi flight mode, and the second operating mode is different than the first operating mode.