IP Library › Patent Application 15856421
Patent Application
App. No. 15/856,421

GEARED ARCHITECTURE FOR HIGH SPEED AND SMALL VOLUME FAN DRIVE TURBINE

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Quick Facts
Patent No.
US None
App. No.
15/856,421
Filed
Dec 28, 2017
Art Unit
3741
USPC
60/226.1
Abstract

A gas turbine engine according to an example of the present disclosure includes, among other things, a fan shaft drivingly connected to a fan with the fan having fan blades. A fan shaft support that supports the fan shaft and a gear system drivingly connected to the fan shaft. The gear system includes a ring gear defining a ring gear lateral stiffness and a ring gear transverse stiffness, a gear mesh defining a gear mesh lateral stiffness and a gear mesh transverse stiffness, and a reduction ratio greater than 2.3. At least one of the ring gear lateral stiffness and said ring gear transverse stiffness is less than 12% of a respective one of the gear mesh lateral stiffness and the gear mesh transverse stiffness.

Claims (34)

1 . A gas turbine engine, comprising:

a fan shaft drivingly connected to a fan, said fan having fan blades;

a fan shaft support that supports said fan shaft;

a gear system drivingly connected to said fan shaft, said gear system includes a ring gear defining a ring gear lateral stiffness and a ring gear transverse stiffness, a gear mesh defining gear mesh lateral stiffness and a gear mesh transverse stiffness, and a reduction ratio greater than 2.3; and

wherein at least one of said ring gear lateral stiffness and said ring gear transverse stiffness is less than 12% of a respective one of said gear mesh lateral stiffness and said gear mesh transverse stiffness.

2 . The gas turbine engine of claim 1 , further comprising a flexible support defining a flexible support lateral stiffness and a flexible support transverse stiffness, wherein at least one of said flexible support lateral stiffness and said flexible support transverse stiffness is less than 8% of a respective one of said gear mesh lateral stiffness and said gear mesh transverse stiffness.

3 . The gas turbine engine of claim 2 , wherein said flexible support transverse stiffness is less than 8% of said gear mesh transverse stiffness.

4 . The gas turbine engine of claim 3 , wherein said flexible support lateral stiffness is less than 8% of said gear mesh lateral stiffness.

5 . The gas turbine engine of claim 3 , further comprising a low fan pressure ratio of less than 1.45 and said low fan pressure ratio is measured across the fan blades alone.

6 . The gas turbine engine of claim 5 , further comprising a low pressure turbine with an inlet, an outlet, and a low pressure turbine pressure ratio greater than 5:1, wherein said low pressure turbine pressure ratio is a ratio of a pressure measured prior to said inlet as related to a pressure at said outlet prior to any exhaust nozzle.

7 . The gas turbine engine of claim 6 , further comprising a bypass ratio greater than ten (10).

8 . The gas turbine engine of claim 7 , further comprising a fan tip speed less than about 1150 ft/second.

9 . The gas turbine engine of claim 7 , further comprising a mid-turbine frame including at least one airfoil extending into a flow path.

10 . The gas turbine engine of claim 9 , further comprising fan bearings supporting said fan shaft, wherein the gear system is located aft of said fan bearings and the gear system is a planetary gear system.

11 . The gas turbine engine of claim 7 , wherein said flexible support lateral stiffness is less than 8% of said gear mesh lateral stiffness.

12 . The gas turbine engine of claim 2 , wherein said flexible support transverse stiffness is less than 8% of said gear mesh transverse stiffness.

13 . The gas turbine engine of claim 1 , further comprising a flexible support defining a flexible support lateral stiffness and a flexible support transverse stiffness, wherein said fan shaft support defines a fan shaft support lateral stiffness and a fan shaft support transverse stiffness and at least one of said flexible support lateral stiffness and said flexible support transverse stiffness is less than 11% of a respective one of said fan shaft support lateral stiffness and said fan shaft support lateral stiffness.

14 . The gas turbine engine of claim 13 , wherein said flexible support transverse stiffness is less than 11% of said fan shaft support transverse stiffness.

15 . The gas turbine engine of claim 13 , further comprising a low fan pressure ratio of less than 1.45 and said low fan pressure ratio is measured across the fan blades alone.

16 . The gas turbine engine of claim 15 , further comprising a low pressure turbine with an inlet, an outlet, and a low pressure turbine pressure ratio greater than 5:1, wherein said low pressure turbine pressure ratio is a ratio of a pressure measured prior to said inlet as related to a pressure at said outlet prior to any exhaust nozzle.

17 . The gas turbine engine of claim 15 , further comprising a bypass ratio greater than ten (10).

18 . The gas turbine engine of claim 17 , further comprising a fan tip speed less than about 1150 ft/second.

19 . The gas turbine engine of claim 17 , further comprising a mid-turbine frame including at least one airfoil extending into a flow path.

20 . The gas turbine engine of claim 17 , wherein the flexible support lateral stiffness is less than 11% of said fan shaft support lateral stiffness.

21 . The gas turbine engine of claim 17 , wherein the flexible support transverse stiffness is less than 11% of said fan shaft support transverse stiffness.

22 . The gas turbine engine of claim 21 , wherein at least one of said flexible support lateral stiffness and said flexible support transverse stiffness is less than 8% of a respective one of said gear mesh lateral stiffness and said gear mesh transverse stiffness.

23 . The gas turbine engine of claim 22 , wherein said flexible support lateral stiffness is less than 11% of said fan shaft support lateral stiffness.

24 . The gas turbine engine of claim 23 , further comprising a fan tip speed less than about 1150 ft/second.

25 . The gas turbine engine of claim 13 , wherein said flexible support lateral stiffness is less than 11% of said fan shaft support lateral stiffness.

26 . The gas turbine engine of claim 25 , wherein said flexible support transverse stiffness is less than 11% of said fan shaft support transverse stiffness.

27 . The gas turbine engine of claim 26 , further comprising a two stage high pressure turbine.

28 . The gas turbine engine of claim 27 , further comprising a low fan pressure ratio of less than 1.45 wherein said low fan pressure ratio is measured across the fan blades alone.

29 . The gas turbine engine of claim 28 , wherein at least one of said flexible support lateral stiffness and said flexible support transverse stiffness is less than 8% of a respective one of said gear mesh lateral stiffness and said gear mesh transverse stiffness.

30 . The gas turbine engine of claim 29 , further comprising a fan tip speed less than about 1150 ft/second.