IP Library › Granted Patent US 12,655,811
Granted Patent B2
US 12,655,811 · App. 18/130,539 · Granted Jun 16, 2026

Geared architecture for high speed and small volume fan drive turbine

Inventors: Michael E. McCune (Colchester, CT); Jason Husband (South Glastonbury, CT); Frederick M. Schwarz (Glastonbury, CT); Daniel Bernard Kupratis (Wallingford, CT); Gabriel L. Suciu (Glastonbury, CT); William K. Ackermann (East Hartford, CT)
Assignee: RTX CORPORATION
F02K3/06F02C3/107F02C7/36F04D29/053F05D2240/60F05D2260/4031F05D2260/40311F05D2300/501
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Quick Facts
Patent No.
US 12,655,811
App. No.
18/130,539
Filed
Apr 4, 2023
Granted
Jun 16, 2026
Kind
B2
Art Unit
3741
USPC
417/405
Abstract

A turbofan engine includes a propulsor section that has a propulsor shaft in driving engagement with a propulsor. An epicyclic gear system has a gear mesh lateral stiffness and a gear mesh transverse stiffness. A gear system input defines a gear system input lateral stiffness and a gear system input transverse stiffness. The gear system input lateral stiffness is less than 5% of the gear mesh lateral stiffness. A first turbine section rotates at a first speed, and a second turbine rotates at a second speed that is faster than the first speed. A first performance quantity is defined as the product of the first speed squared and the first area of the first turbine, a second performance quantity is defined as the product of the second speed squared and the second area of the second turbine, and a performance quantity ratio is between 0.5 and 1.5.

Claims (47)

1 . A turbofan engine comprising:

a propulsor section including a propulsor shaft in driving engagement with a propulsor having blades extending from a propulsor hub and being rotatable about a central longitudinal axis of said turbofan engine;

an epicyclic gear system in driving engagement with said propulsor shaft and having a gear mesh lateral stiffness and a gear mesh transverse stiffness;

a gear system input to said epicyclic gear system defining a gear system input lateral stiffness and a gear system input transverse stiffness, wherein said gear system input lateral stiffness is less than 5% of said gear mesh lateral stiffness;

a first turbine section in driving engagement with said gear system input and rotatable about said central longitudinal axis and said first turbine section includes an inlet and an outlet; and

a second turbine section,

wherein said first turbine section has a first exit area at a first exit point at said outlet and rotates at a first speed,

wherein said second turbine section has a second exit area at a second exit point and rotates at a second speed, which is faster than said first speed,

wherein a first performance quantity is defined as the product of said first speed squared and said first area,

wherein a second performance quantity is defined as the product of said second speed squared and said second area,

wherein a performance quantity ratio of said first performance quantity to said second performance quantity is between 0.5 and 1.5.

2 . The turbofan engine as set forth in claim 1 , wherein said epicyclic gear system includes a ring gear having a ring gear lateral stiffness and a ring gear transverse stiffness, and said ring gear lateral stiffness is less than 12% of said gear mesh lateral stiffness.

3 . The turbofan engine as set forth in claim 2 , wherein said first turbine has between three and six stages and said second turbine has two stages.

4 . The turbofan engine as set for in claim 3 , wherein said second speed is more than twice said first speed.

5 . The turbofan engine as set forth in claim 3 , wherein there being a flexible support to support said epicyclic gear system, said flexible support having a flexible support lateral stiffness and a flexible support transverse stiffness, a frame which supports said propulsor shaft having a frame lateral stiffness and a frame transverse stiffness, and at least one of said flexible support lateral stiffness and said flexible support transverse stiffness being less than 11% of a respective one of said frame lateral stiffness and said frame transverse stiffness.

6 . The turbofan engine as set forth in claim 5 , wherein said gear system input connects a sun gear of said epicyclic gear system to be driven by said first turbine section, and said gear system input lateral stiffness and said gear system input transverse stiffness being less than 11% of a respective one of said frame lateral stiffness and said frame transverse stiffness.

7 . The turbofan engine as set forth in claim 5 , wherein said performance quantity ratio is greater than or equal to 0.5 and less than or equal to 1.075.

8 . The turbofan engine as set forth in claim 5 , wherein said gear system input transverse stiffness is less than 5% of said gear mesh transverse stiffness.

9 . The turbofan engine as set forth in claim 1 , wherein said first turbine has between three and six stages and said second turbine has two stages.

10 . The turbofan engine as set forth in claim 9 , wherein there being a flexible support to support said epicyclic gear system, said flexible support having a flexible support lateral stiffness and a flexible support transverse stiffness, and at least one of said flexible support lateral stiffness and said flexible support transverse stiffness being less than 8% of a respective one of said gear mesh lateral stiffness and said gear mesh transverse stiffness.

11 . The turbofan engine as set forth in claim 9 , wherein there being a flexible support to support said epicyclic gear system, said flexible support having a flexible support lateral stiffness and a flexible support transverse stiffness, and said flexible support lateral stiffness and said flexible support transverse stiffness being less than 8% of a respective one of said gear mesh lateral stiffness and said gear mesh transverse stiffness.

12 . The turbofan engine as set for in claim 1 , wherein the propulsor section is a fan section, the propulsor is a fan, the propulsor hub is a fan hub, and an outer housing surrounds the fan to define a bypass duct.

13 . The turbofan engine as set forth in claim 12 , wherein said first turbine section having between three and six stages and said second turbine section having two stages.

14 . The turbofan engine as set forth in claim 13 , wherein, said epicyclic gear system includes a ring gear having a ring gear lateral stiffness and a ring gear transverse stiffness and said ring gear lateral stiffness is less than 12% of said gear mesh lateral stiffness.

15 . The turbofan engine as set forth in claim 14 , wherein said ring gear transverse stiffness is less than 12% of said gear mesh transverse stiffness.

16 . The turbofan engine as set forth in claim 14 , wherein there being a flexible support to support said epicyclic gear system, said flexible support having a flexible support lateral stiffness and a flexible support transverse stiffness, and at least one of said flexible support lateral stiffness and said flexible support transverse stiffness being less than 8% of a respective one of said gear mesh lateral stiffness and said gear mesh transverse stiffness.

17 . The turbofan engine as set forth in claim 16 , wherein at least one of said flexible support lateral stiffness and said flexible support transverse stiffness is less than 11% of a respective one of a frame lateral stiffness and a frame transverse stiffness of a frame which supports said fan shaft.

18 . The turbofan engine as set forth in claim 16 , wherein a frame which supports said fan shaft defines a frame lateral stiffness and a frame transverse stiffness and said gear system input lateral stiffness and said gear system input transverse stiffness are less than 11% of a respective one of said frame lateral stiffness and said frame transverse stiffness.

19 . The turbofan engine as set forth in claim 18 , wherein said performance quantity ratio is above or equal to 0.8 and less than or equal to 1.075.

20 . A turbofan engine comprising:

a propulsor section including a propulsor shaft in driving engagement with a propulsor having blades extending from a propulsor hub and being rotatable about a central longitudinal axis of said turbofan engine;

an epicyclic gear system in driving engagement with said propulsor shaft and having a gear mesh lateral stiffness and a gear mesh transverse stiffness; and

a gear system input to said epicyclic gear system defining a gear system input lateral stiffness and a gear system input transverse stiffness, wherein said gear system input transverse stiffness is less than 5% of said gear mesh transverse stiffness;

a first turbine section in driving engagement with said gear system input and rotatable about said central longitudinal axis and said first turbine section includes an inlet and an outlet; and

a second turbine section,

wherein said first turbine section has a first exit area at a first exit point at said outlet and rotates at a first speed,

wherein said second turbine section has a second exit area at a second exit point and rotates at a second speed, which is faster than said first speed,

wherein a first performance quantity is defined as the product of said first speed squared and said first area,

wherein a second performance quantity is defined as the product of said second speed squared and said second area,

wherein a performance quantity ratio of said first performance quantity to said second performance quantity is between 0.5 and 1.5.

21 . The turbofan engine as set forth in claim 20 , wherein said epicyclic gear system includes a ring gear having a ring gear lateral stiffness and a ring gear transverse stiffness and said ring gear lateral stiffness is less than 12% of said gear mesh lateral stiffness.

22 . The turbofan engine as set forth in claim 21 , wherein there being a flexible support to support said epicyclic gear system, said flexible support having a flexible support lateral stiffness and a flexible support transverse stiffness, and at least one of said flexible support lateral stiffness and said flexible support transverse stiffness being less than 8% of a respective one of said gear mesh lateral stiffness and said gear mesh transverse stiffness.

23 . The turbofan engine as set forth in claim 22 , wherein said first turbine has between three and six stages and said second turbine has two stages.

24 . The turbofan engine as set forth in claim 23 , said gear system input lateral stiffness is less than 5% of said gear mesh lateral stiffness.

25 . The turbofan engine as set forth in claim 24 , wherein at least one of said flexible support lateral stiffness and said flexible support transverse stiffness is less than 11% of a respective one of a frame lateral stiffness and a frame transverse stiffness of a frame which supports said propulsor shaft.

26 . The turbofan engine as set for in claim 25 , wherein said second speed is more than twice said first speed.

27 . The turbofan engine as set forth in claim 26 , wherein said gear system input lateral stiffness and said gear system input transverse stiffness are less than 11% of a respective one of said frame lateral stiffness and said frame transverse stiffness.

Assignments (1)
CHANGE OF NAME Recorded Jul 27, 2023
From: RAYTHEON TECHNOLOGIES CORPORATION
To: RTX CORPORATION
Reel/Frame 064402/0837 →
Continuity (8)
Continuation 17342100 · Jun 8, 2021
Continuation 15881240 · Jan 26, 2018
Continuation 15485512 · Apr 12, 2017
Continuation 13908177 · Jun 3, 2013
Continuation In Part 13623309 · Sep 20, 2012
Continuation In Part 13342508 · Jan 3, 2012
Provisional Application 61494453 · Jun 8, 2011
Related Publication 20230235715A1 · Jul 27, 2023
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