TURBOPROP ENGINE WITH COMPRESSOR TURBINE SHROUD

• US 20140069107A1
• Filed: 09/13/2012
• Published: 03/13/2014
• Est. Priority Date: 09/13/2012
• Status: Active Grant

• Current Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Original Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Inventors: Macfarlane, Ian Alexander
• Granted Patent: US 9,410,441 B2
• Time in Patent Office: Days
• US Class Current: 60/797
• CPC Class Codes: B64D 27/10 of gas-turbine type jet aircraft B64D27/16
• CPC Class Codes: F01D 11/08 for sealing space between rotor blade tips and stator specially-shaped blade tips therefor F01D5/20
• CPC Class Codes: F01D 25/246 Fastening of diaphragms or stator-rings
• CPC Class Codes: F02C 3/10 with another turbine driving an output shaft but not driving the compressor
• CPC Class Codes: F02C 6/206 the vehicles being airscrew driven
• CPC Class Codes: F02C 7/20 Mounting or supporting of plant; Accommodating heat expansion or creep
• CPC Class Codes: F05D 2230/642 using maintaining alignment while permitting differential dilatation
• CPC Class Codes: F05D 2250/411 in rotation
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft
• CPC Class Codes: Y10T 29/49236 Fluid pump or compressor making

Abstract

A turboprop engine including an annular outer case including a mount ring for attachment to an aircraft along a plane to transfer loads from a propeller and having an annular flange extending radially inwardly therefrom within the plane, an annular turbine support case received within the outer case and connected to the outer case only through a direct connection with the annular flange allowing a limited relative pivoting motion between the turbine support case and the mount ring, and a turbine section including a rotor closely surrounded by a shroud with an annular tip clearance being defined therebetween, the shroud being directly connected to and located by the turbine support case. A method of isolating a turbine shroud from propeller loads in a propeller engine is also disclosed.

Claims

1. A turboprop engine comprising:

an annular outer case including a mount ring for attachment to an aircraft along a plane to transfer loads from a propeller, the mount ring having an annular flange extending radially inwardly therefrom within the plane;

an annular turbine support case received within the outer case and connected to the outer case only through a direct connection with the annular flange allowing a limited relative pivoting motion between the turbine support case and the mount ring; and

a turbine section including a rotor closely surrounded by a shroud with an annular tip clearance being defined therebetween, the shroud being directly connected to and located by the turbine support case..

2. The engine as defined in claim 1, wherein the mount ring is a single plane mount.

3. The engine as defined in claim 1, wherein the turbine section further includes at least one stator supported along an outer perimeter thereof by the turbine support case.

4. The engine as defined in claim 1, wherein the turbine support case includes an annular outer section extending downstream and radially inwardly from the flange and an annular inner section extending upstream and radially inwardly from a downstream end of the outer section, an upstream end of the inner section being directly connected to the shroud.

5. The engine as defined in claim 1, wherein the turbine support case includes a radially outwardly extending flange connected to the flange of the mount ring, the turbine support case including an end wall extending axially beyond the flange thereof toward the flange of the mount ring and abutting an adjacent portion of the outer case, the flanges of the mount ring and of the turbine support case being interconnected by a circumferential array of fasteners extending therethrough, and a spring member being compressed between the turbine support case and the adjacent portion of the outer case, radially inwardly of the fasteners.

6. The engine as defined in claim 5, wherein the outer case includes a downstream portion extending downstream from the mounting ring radially outwardly of the flange and around the turbine support case, and an upstream portion extending upstream from the flange of the mount ring, the spring member being compressed between the turbine support case and the upstream portion.

7. The engine as defined in claim 6, wherein the upstream portion includes a radially outwardly extending flange received between the flange of the mount ring and the flange of the turbine support case and connected to the flange of the mount ring by the fasteners, the end wall of the turbine support case abutting the flange of the upstream portion.

8. A turboprop engine comprising:

an annular outer case including a mount ring for attachment to an aircraft along a plane, the mount ring having an annular flange extending radially inwardly therefrom within the plane, the annular outer case including a portion extending from the mount ring to a support of a shaft of the engine and defining a load path for loads from a propeller;

an annular turbine support case received within the outer case and connected to the outer case only through a direct connection with the annular flange, the support case extending free of the load path;

a turbine section received within the outer case and including a rotor in driving engagement with the shaft and closely surrounded by a shroud with an annular tip clearance being defined therebetween, the shroud being directly connected to and located by the turbine support case.

9. The engine as defined in claim 8, wherein the direct connection between the annular flange and the turbine support case allows a limited relative pivoting motion between the turbine support case and the mount ring.

10. The engine as defined in claim 8, wherein the mount ring is a single plane mount.

11. The engine as defined in claim 8, wherein the turbine section includes at least one stator supported around an outer perimeter thereof by the support case.

12. The engine as defined in claim 11, wherein the support case includes an annular outer section extending downstream and radially inwardly from the flange and an annular inner section extending upstream and radially inwardly from a downstream end of the outer section, the inner section supporting the at least one stator of the low pressure section, an upstream end of the inner section being directly connected to the shroud.

13. The engine as defined in claim 8, wherein the support case includes a radially outwardly extending flange connected to the flange of the mount ring, the support case including an end wall extending axially beyond the flange thereof toward the flange of the mount ring and abutting an adjacent portion of the outer case, the flanges of the mount ring and of the support case being interconnected by a circumferential array of fasteners extending therethrough, and a spring member being compressed between the support case and the adjacent portion of the outer case, radially inwardly of the fasteners.

14. The engine as defined in claim 13, wherein the portion of the outer case is an upstream portion extending upstream from the flange of the mount ring, the spring member being compressed between the support case and the upstream portion, the outer case further comprising a downstream portion extending downstream from the mounting ring radially outwardly of the flange and around the support case.

15. The engine as defined in claim 14, wherein the upstream portion includes a radially outwardly extending flange received between the flange of the mount ring and the flange of the support case and connected to the flange of the mount ring by the fasteners, the end wall of the support case abutting the flange of the upstream portion.

16. The engine as defined in claim 15, wherein the upstream portion includes an end wall extending axially beyond the flange thereof and surrounded by the end wall of the support case, the spring member being received between the end wall of the upstream portion and an adjacent shoulder of the turbine support case.

17. A method of isolating a turbine shroud from propeller loads in a propeller engine having an outer case with a mount for attachment of the engine to an aircraft along a plane to transfer the propeller loads, the method comprising:

supporting a shaft of the engine with a portion of the outer case extending from the mount and defining a load path for the propeller loads through the portion of the outer case;

attaching a turbine support case to extend free of the load path including attaching the turbine support case to the outer case only through a connection along the plane allowing a limited relative pivoting motion between the turbine support case and the mount; and

locating the turbine shroud by directly connecting the shroud to the turbine support case.

18. The method as defined in claim 17, wherein attaching the turbine support case includes attaching an upstream end of an annular outer section of the turbine support case to a flange extending radially inwardly from the mount within the plane.

19. The method as defined in claim 18, wherein attaching the turbine support case includes attaching a radially outwardly extending flange of the turbine support case to the flange of the mount ring with an annular space being defined therebetween while abutting an end wall of the turbine support case extending beyond the flange thereof with a part of the outer case, and biasing the turbine support case and the portion of the outer case away from each other radially inwardly of the flange of the turbine support case and of the abutted end wall.

20. The method as defined in claim 19, wherein attaching the turbine support case further includes attaching the flange of the turbine support case to a flange of the portion of the outer case extending between the flange of the mount ring and the flange of the turbine support case, and abutting the end wall of the turbine support case to the portion of the outer case includes abutting the end wall of the turbine support case to the flange of the portion of the outer case.