REVERSE FLOW GAS TURBINE ENGINE WITH OFFSET RGB

• US 20180073429A1
• Filed: 01/17/2017
• Published: 03/15/2018
• Est. Priority Date: 09/15/2016
• Status: Active Grant

• Current Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Original Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Inventors: DUBREUIL, Jean
• Granted Patent: US 11,035,293 B2
• Time in Patent Office: Days
• CPC Class Codes: F02C 3/107 with two or more rotors connected by power transmission
• CPC Class Codes: F02C 3/145 the combustion chamber being in the reverse flow-type
• CPC Class Codes: F02C 6/206 the vehicles being airscrew driven
• CPC Class Codes: F02C 7/32 Arrangement, mounting, or driving, of auxiliaries
• CPC Class Codes: 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
• CPC Class Codes: F05D 2220/324 to drive unshrouded, low solidity propeller
• CPC Class Codes: F05D 2220/329 in helicopters
• CPC Class Codes: F05D 2220/76 an electrical generator
• CPC Class Codes: F05D 2260/53 using gears
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A gas turbine engine has an engine case housing a low pressure compressor drivingly connected to a low pressure turbine by a low pressure compressor shaft extending along an engine axis. The low pressure turbine is disposed forward of the low pressure compressor. A low pressure turbine shaft is drivingly connected to the low pressure turbine and extends forwardly of the low pressure turbine. A reduction gear box (RGB) is drivingly connected to the low pressure turbine shaft. The RGB is offset from the engine axis to free an access to low pressure compressor shaft connection. The offset positioning of the RGB allows to provide an access port in an axially forwardly facing surface of the engine case to access the low pressure compressor shaft and more particularly a connection thereof to the LP turbine.

Claims

1. A gas turbine engine comprising:

an engine case housing a low pressure compressor drivingly connected to a low pressure turbine by a low pressure compressor shaft extending along an engine axis, the low pressure turbine disposed forward of the low pressure compressor, a low pressure turbine shaft drivingly connected to the low pressure turbine and extending forward of the low pressure turbine, a reduction gear box (RGB) drivingly connected to the low pressure turbine shaft forward of the low pressure turbine, the RGB radially offset from the engine axis, and an access port defined in an axially forwardly facing surface of the engine case, the port disposed to provide access to the low pressure compressor shaft.

2. The gas turbine engine defined in claim 1, wherein the low pressure compressor shaft concentrically extends into the low pressure turbine shaft and has a connection thereto, the connection of the low pressure compressor shaft accessible via the access port through the low pressure turbine shaft.

3. The gas turbine engine defined in claim 1, further comprising a high pressure compressor drivingly connected to a high pressure turbine via a high pressure shaft, the high pressure compressor disposed forward of the low pressure compressor and in fluid flow communication therewith to receive pressurized air therefrom, the high pressure turbine disposed aft of the low pressure turbine and in fluid communication therewith.

4. The gas turbine engine defined in claim 1, wherein the RGB has an output shaft drivingly connected to a rotatable load selected from a group consisting of:

a propeller, a helicopter rotor and a generator.

5. The gas turbine engine defined in claim 1, wherein the low pressure compressor shaft is drivingly connected to the low pressure turbine via the low pressure turbine shaft.

6. The gas turbine engine defined in claim 5, wherein a mechanical connection is provided between the low pressure compressor shaft and the low pressure turbine shaft, the connection being accessible via the access port, the access port disposed in-line with the low pressure compressor shaft and the low pressure turbine shaft.

7. The gas turbine engine as defined in claim 3, further comprising an accessory gearbox (AGB) disposed aft of the low pressure compressor axially in-line with the engine axis.

8. The gas turbine engine as defined in claim 7, wherein an air inlet is disposed between the low pressure compressor and the AGB.

9. The gas turbine engine as defined in claim 1, wherein the RGB is off-centered radially away from the engine axis by a distance sufficient to provide an axial access to the low pressure compressor shaft via the axially forwardly facing surface of the engine case.

10. The gas turbine engine as defined in claim 1, wherein an output gear is provided at a forward end of the low pressure turbine shaft in meshing engagement with an input gear of the RGB, the input gear mounted for rotation about an axis which is radially offset from the low pressure turbine shaft.

11. A gas turbine engine comprising:

an output drive shaft having a front end configurable to drivingly engage a rotatable load;

a low pressure (LP) turbine drivingly connected to the drive shaft via a reduction gear box (RGB), an LP compressor drivingly connected to the LP turbine via an LP compressor shaft, the LP turbine disposed forward of the LP compressor;

a high pressure (HP) turbine drivingly connected to an HP compressor via an HP shaft, the HP compressor disposed forward of the LP compressor and in fluid communication therewith for receiving pressurized air therefrom, the HP turbine disposed aft of the LP turbine and in fluid communication therewith;

wherein the RGB is radially offset from the LP compressor shaft to provide axial access thereto via a front end of the engine.

12. The gas turbine engine as defined in claim 11, further comprising an engine case, the engine case having an access port axially aligned with the LP compressor shaft.

13. The gas turbine engine as defined in claim 12, further comprising an accessory gearbox (AGB) disposed aft of the LP compressor and in axial alignment therewith.

14. The gas turbine engine as defined in claim 11, wherein the LP turbine is drivingly connected to an LP turbine shaft projecting forwardly from the LP turbine, the LP turbine shaft drivingly connected to the RGB, and wherein the LP compressor shaft extends coaxially into the LP turbine shaft, the LP compressor shaft axially accessible via the LP turbine shaft.

15. The gas turbine engine as defined in claim 14, wherein the LP turbine shaft carries an output gear, which is in meshing engagement with an input gear of the RGB, the input gear of the RGB having an output axis that is off-centered relative to the LP turbine shaft.

16. The gas turbine engine as defined in claim 12, wherein the LP turbine has an LP turbine shaft projecting axially forwardly from a forward side of the LP turbine, the access port providing access to an axially extending bore of the LP turbine shaft, the LP compressor shaft accessible via said axially extending bore.

17. The gas turbine engine as defined in claim 16, wherein a connection is provided between the LP compressor shaft and the LP turbine shaft in the axially extending bore, the access port providing access to the connection.