# US 10,767,567 B2 · Multi-spool gas turbine engine architecture

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- Number: US 10,767,567 B2
- Document ID: US10767567B2
- Status: Granted
- Kind: B2
- Application number: 15/407,445
- Filed: 2017-01-17
- Published: 2018-01-25
- Granted: 2020-09-08
- Earliest claimed: 2016-07-19
- Assignees: Pratt & Whitney Canada Corp.
- Applicants: Pratt & Whitney Canada Corp.
- Inventors: Guy Lefebvre
- Web page: https://patentgrep.com/patent/US10767567B2

## 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)
- B64D 27/10: of gas-turbine type (jet aircraft B64D27/16)
- B64D 35/04: characterised by the transmission driving a plurality of propellers or rotors
- F01D 5/026: {Shaft to shaft connections}
- F01D 15/12: Combinations with mechanical gearing (driven by multiple engines F01D13/00)
- F01D 25/18: Lubricating arrangements (of machines or engines in general F01M)
- F02C 3/08: the compressor comprising at least one radial stage (F02C3/10 takes precedence)
- F02C 3/10: with another turbine driving an output shaft but not driving the compressor
- F02C 3/107: with two or more rotors connected by power transmission
- F02C 3/113: with variable power transmission between rotors
- F02C 3/145: {the combustion chamber being in the reverse flow-type}
- F02C 6/206: {the vehicles being airscrew driven}
- F02C 7/06: Arrangements of bearings (bearings F16C); Lubricating ({of turbo machines F01D25/18; of machines or} engines in general F01M)
- F02C 7/32: Arrangement, mounting, or driving, of auxiliaries
- F02K 3/06: with front fan
- F16H 57/0495: {with fixed gear ratio}
- F05D 2220/32: in gas turbines
- F05D 2220/323: for aircraft propulsion, e.g. jet engines
- F05D 2220/324: to drive unshrouded, low solidity propeller
- F05D 2220/329: in helicopters
- F05D 2230/70: Disassembly methods
- F05D 2230/72: Maintenance
- F05D 2240/61: Hollow
- F05D 2250/36: in inner-outer relationship, e.g. shaft-bearing arrangements
- F05D 2260/31: Retaining bolts or nuts
- F05D 2260/36: by a form fit connection, e.g. by interlocking
- F05D 2260/40: Transmission of power
- F05D 2260/4031: as in toothed gearing
- F05D 2260/40311: of the epicyclical, planetary or differential type
- F05D 2260/98: Lubrication
- Y02T 50/40: Weight reduction
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- 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)
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- 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)
- F16H: GEARING
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A multi-spool gas turbine engine comprises a low pressure (LP) spool and a high pressure (HP) spool. The LP spool and the HP spool are independently rotatable about an axis. The LP pressure spool has an LP compressor and an LP turbine. The HP spool has an HP turbine and an HP compressor. An accessory gear box (AGB) is axially mounted at one end of the engine. The LP compressor is axially positioned between the HP compressor and the AGB. The AGB is drivingly connected to the HP spool through the center of the LP compressor.

## Claims

### Claim 1

A multi-spool gas turbine engine comprising: a low pressure (LP) spool; a high pressure (HP) spool, the LP spool and the HP spool being independently rotatable from one another about a central axis, the LP pressure spool comprising an LP compressor and an LP turbine, the HP spool comprising an HP turbine and an HP compressor; and an accessory gear box (AGB) mounted in axial series at one end of the engine, the LP compressor being positioned between the HP compressor and the AGB, the AGB being drivingly connected to the HP spool through the center of the LP compressor, wherein the engine is an aircraft engine having a reverse flow configuration including an air inlet disposed aft of the LP compressor along a direction of travel of the aircraft engine, and wherein the AGB is disposed aft of the air inlet.

### Claim 2 (depends on 1)

The multi-spool gas turbine engine defined in claim 1, wherein the AGB has an input shaft, the input shaft extending along the central axis through a central bore of the LP compressor.

### Claim 3 (depends on 2)

The multi-spool gas turbine engine defined in claim 2, wherein the input shaft of the AGB is drivingly connected to the HP compressor via a gear train, the gear train being positioned axially between the HP compressor and the LP compressor.

### Claim 4 (depends on 3)

The multi-spool gas turbine engine defined in claim 3, wherein the gear train is disposed radially inwardly from a gas path of the engine.

### Claim 5 (depends on 1)

The multi-spool gas turbine engine defined in claim 1, wherein the LP turbine is drivingly connected to an LP shaft, which is, in turn, drivingly connected to the LP compressor via a gear train.

### Claim 6 (depends on 5)

The multi-spool gas turbine engine defined in claim 5, wherein the gear train drivingly connecting the LP shaft to the LP compressor is positioned axially between the HP compressor and the LP compressor.

### Claim 7 (depends on 5)

The multi-spool gas turbine engine defined in claim 5, wherein a gear ratio of the gear train is selected to rotate the LP compressor at a different speed than the LP turbine.

### Claim 8 (depends on 1)

The multi-spool engine defined in claim 1, wherein the aircraft engine is a turboprop engine including a propeller mounted at the front end of the engine, the propeller being driven by the LP turbine via a reduction gear box.

### Claim 9

A multi-spool gas turbine engine comprising: a low pressure (LP) spool; a high pressure (HP) spool; the LP spool and the HP spool being mounted for rotation about a central axis; the LP pressure spool comprising an LP compressor and an LP turbine, the HP spool comprising an HP turbine and an HP compressor; and an accessory gear box (AGB) drivingly connected to the HP spool, the LP compressor being axially positioned between the HP compressor and the AGB and drivingly connected to the LP turbine via a gear train, wherein the AGB has a drive input shaft extending along the central axis through a central bore of the LP compressor, the drive input shaft being drivingly connected to the HP spool, wherein the LP turbine is drivingly mounted to an LP shaft extending axially along the central axis within an HP shaft connecting the HP turbine to the HP compressor, the LP shaft having one end thereof projecting axially out of the HP shaft, said gear train being provided at said one end of the LP shaft.

### Claim 10 (depends on 9)

The multi-spool gas turbine engine defined in claim 9, wherein the gear train is positioned axially between the HP compressor and the LP compressor.

### Claim 11 (depends on 9)

The multi-spool gas turbine engine defined in claim 9, wherein the gear train is contained within a central cavity circumscribed by a compressor inner gaspath wall between the HP compressor and the LP compressor.

### Claim 12

The multi-spool gas turbine engine defined 10, wherein the gear train comprises a first gear mounted to said one end of the LP shaft, said first gear being in meshing engagement with a second gear provided at a first end of a transfer shaft, a third gear provided at a second end of the transfer shaft, and a fourth gear provided on said LP compressor, the fourth gear being in meshing engagement with the third gear.

### Claim 13 (depends on 9)

The multi-spool gas turbine engine defined in claim 9, wherein the engine is an aircraft engine, and wherein the AGB is aft of the LP compressor along a direction of travel of the aircraft engine, the LP compressor is aft of the HP compressor, the HP compressor is aft of the HP turbine, the HP turbine is aft of the LP turbine, and wherein the LP turbine is drivingly connected to an output drive shaft having a front end configured to drivingly engaged a rotatable load, the LP turbine being aft of the front end of the output drive shaft.

### Claim 14

A turboprop or turboshaft engine comprising: an output drive shaft configured to drivingly engage a rotatable load; a low pressure (LP) spool comprising an LP turbine and an LP compressor, the output drive shaft being drivingly connected to the LP turbine, the LP compressor being drivingly connected to the LP turbine via a first gear train; a high pressure (HP) spool rotatable independently of the LP spool, and an accessory gearbox (AGB) drivingly connected to the HP compressor, the LP compressor being positioned axially between the AGB and the HP compressor, and wherein the AGB has an input axis coaxial to a centerline of the LP compressor, wherein the AGB has an input drive shaft extending axially through a central bore of the LP compressor, the input drive shaft being drivingly connected to the HP compressor via a second gear train.

### Claim 15 (depends on 14)

The turboprop or turbofan engine defined in claim 14, wherein the first gear train is axially positioned between the HP compressor and the LP compressor radially inwardly of a gaspath fluidly interconnecting the HP compressor to the LP compressor.

### Claim 16 (depends on 14)

The turboprop or turbofan engine defined in claim 14, wherein the first and second gear trains are contained in a common cavity circumscribed by a compressor inner gaspath wall.

### Claim 17

A reverse flow gas turbine engine, comprising:
an output drive shaft having a front end configurable to drivingly engage a rotatable load;
a low pressure (LP) spool including an LP turbine drivingly engaged to the output drive shaft, and an LP compressor drivingly connected to the LP turbine via a gear train for rotation about a centerline;
a high pressure HP spool including an HP turbine and an HP compressor drivingly engaged to an HP shaft rotatable independently of the LP spool, the HP compressor in fluid communication with the LP compressor, and the HP turbine in fluid communication with the LP turbine; and
an accessory gearbox (AGB) having an input axis coaxial to the centerline, wherein the AGB has a drive input shaft extending along the centerline through a central bore of the LP compressor, the drive input shaft being drivingly connected to the HP spool.

### Claim 18 (depends on 17)

The reverse flow gas turbine engine defined in claim 17, wherein the gear train is contained within a central cavity circumscribed by a compressor inner gaspath wall.