TRACTION DRIVE TRANSMISSION FOR GAS TURBINE ENGINE ACCESSORY GEARBOX

• US 20180171815A1
• Filed: 11/30/2017
• Published: 06/21/2018
• Est. Priority Date: 12/16/2016
• Status: Abandoned Application

• Current Assignee: Raytheon Technologies Corporation d/b/a RTX
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Suciu, Gabriel L., Merry, Brian, Sheridan, William G., McCune, Michael E.
• Application Number:
  US15/827,132
• Publication Number:
  US 20180171815A1
• Time in Patent Office: Days
• CPC Class Codes: F01D 15/08 Adaptations for driving, or combinations with, pumps
• CPC Class Codes: F01D 15/10 Adaptations for driving, or combinations with, electric generators
• CPC Class Codes: F01D 15/12 Combinations with mechanical gearing driven by multiple engines F01D13/00
• CPC Class Codes: F01D 25/16 Arrangement of bearings; Supporting or mounting bearings in casings bearings per se F16C
• CPC Class Codes: F01D 25/18 Lubricating arrangements of machines or engines in general F01M
• CPC Class Codes: F01D 25/20 using lubrication pumps
• CPC Class Codes: F01D 5/06 Rotors for more than one axial stage, e.g. of drum or multiple disc type; Details thereof, e.g. shafts, shaft connections F01D5/022, F01D5/023 take precedence
• 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 2220/32 in gas turbines
• CPC Class Codes: F05D 2240/60 Shafts
• CPC Class Codes: F05D 2260/402 through friction drives
• CPC Class Codes: F05D 2260/4031 as in toothed gearing
• CPC Class Codes: F05D 2270/024 to keep rotational speed constant
• CPC Class Codes: F16H 1/222 with non-parallel axes
• CPC Class Codes: F16H 15/04 Gearings providing a continuous range of gear ratios
• CPC Class Codes: F16H 37/021 toothed gearing combined with continuous variable friction gearing

Abstract

A gas turbine engine assembly according to an example of the present disclosure includes, among other things, a turbine section having first and second turbines mounted for rotation about a common rotational axis within an engine static structure, first and second turbine shafts coaxial with one another and to which the first and second turbines are respectively operatively mounted, an accessory drive gearbox a first towershaft interconnecting the accessory drive gearbox and the first or second turbine shaft, and a multispeed transmission interconnecting the accessory drive gearbox and at least one accessory component.

Claims

1. A gas turbine engine assembly comprising:

a turbine section having first and second turbines mounted for rotation about a common rotational axis within an engine static structure;

first and second turbine shafts coaxial with one another and to which the first and second turbines are respectively operatively mounted;

an accessory drive gearbox;

a first towershaft interconnecting the accessory drive gearbox and the first or second turbine shaft; and

a multispeed transmission interconnecting the accessory drive gearbox and at least one accessory component.

2. The gas turbine engine assembly of claim 1, wherein the multispeed transmission includes an output shaft coupled to the at least one accessory component, and the multispeed transmission varies a rotational speed of the output shaft relative to the first towershaft during operation.

3. The gas turbine engine assembly of claim 2, wherein the multispeed transmission is a traction drive transmission.

4. The gas turbine engine assembly of claim 2, wherein the at least one accessory component includes at least one of an electric machine and a hydraulic pump.

5. The gas turbine engine assembly of claim 2, wherein the first towershaft is geared to the first or second turbine shaft such that a rotational speed of the first towershaft and a first set of gears of the accessory drive gearbox varies linearly with a rotational speed of the first or second turbine shaft, with the multispeed transmission driven by the first set of gears.

6. The gas turbine engine assembly of claim 5, further comprising an oil pump driven by the first set of gears at a fixed ratio relative to the rotational speed of the first towershaft, wherein the oil pump delivers fluid to a bearing system including a bearing that supports the first turbine shaft, and the first towershaft is rotatably coupled to the first turbine shaft.

7. The gas turbine engine assembly of claim 5, further comprising an electronic engine control coupled to the multispeed transmission that causes the output shaft to rotate within a defined range.

8. The gas turbine engine assembly of claim 1, wherein:

the first and second turbine shafts are inner and outer shafts, respectively; and

the first and second turbines are low and high pressure turbines, respectively.

9. The gas turbine engine assembly of claim 8, wherein the second turbine shaft is rotatable at a higher speed than the first turbine shaft during operation.

10. The gas turbine engine assembly of claim 9, wherein the multispeed transmission includes an output shaft coupled to the at least one accessory component, and the multispeed transmission varies a rotational speed of the output shaft relative to the first towershaft during operation.

11. The gas turbine engine assembly of claim 10, wherein the multispeed transmission is a continuously variable transmission defining a continuous range of effective gear ratios.

12. The gas turbine engine assembly of claim 9, further comprising a second towershaft rotatably coupled to another one of the first or second turbine shaft, wherein the accessory drive gearbox includes a housing in which a first set of gears and a second set of gears are arranged, the first towershaft interconnecting the first set of gears and the first turbine shaft, and the second towershaft interconnecting the second set of gears and the second turbine shaft.

13. A method of driving accessories through an accessory gearbox of a gas turbine engine, comprising:

rotating a first turbine shaft to drive a first towershaft, the first turbine shaft mounted for rotation about a common rotational axis with a second turbine shaft, the first turbine shaft coupled to a first turbine, and the second turbine shaft coupled to a second turbine;

driving a first set of gears of an accessory drive gearbox with the first towershaft; and

driving a multispeed transmission with the first set of gears to rotate at least one accessory component at a first speed that differs from a second speed of the first towershaft.

14. The method of claim 13, wherein the multispeed transmission includes an output shaft that drives the at least one accessory component, and the step of driving the multispeed transmission includes varying a rotational speed of the output shaft relative to the first towershaft.

15. The method of claim 14, wherein the step of driving a multispeed transmission includes driving the at least one accessory component within a first range of rotational speeds that is less than a second range of rotational speeds of the first towershaft.

16. The method of claim 15, wherein the multispeed transmission is a traction drive transmission.

17. The method of claim 13, wherein the at least one accessory component includes at least one of an electric machine and a hydraulic pump.

18. The method of claim 13, further comprising:

driving an oil pump with the first set of gears to supplying oil to a bearing system, the bearing system including a bearing supporting the first turbine shaft, and the first turbine shaft coupled to a geared architecture; and

driving a fan through the geared architecture such that the fan rotates at a lower speed than the first turbine shaft.

19. The method of claim 18, further comprising rotating the second turbine shaft at a higher speed than the first turbine shaft.

20. The method of claim 19, wherein the step of driving the oil pump includes supplying oil to the bearing system during a windmilling event.