De-rotation system for a counter-rotating, coaxial rotor hub shaft fairing

• US 20070181741A1
• Filed: 05/12/2006
• Published: 08/09/2007
• Est. Priority Date: 05/26/2005
• Status: Active Grant

• Current Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Original Assignee: Sikorsky Aircraft Corporation (Martin Marietta Corporation)
• Inventors: Bertolotti, Fabio, D'Anna, Frank, Darrow, David, Sbabo, Thomas
• Granted Patent: US 7,621,480 B2
• Time in Patent Office: Days
• US Class Current: 244/17.230
• CPC Class Codes: B64C 1/00 Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
• CPC Class Codes: B64C 27/04 Helicopters
• CPC Class Codes: B64C 27/10 arranged coaxially
• CPC Class Codes: B64C 27/12 Rotor drives
• CPC Class Codes: B64C 27/14 Direct drive between power plant and rotor hub
• CPC Class Codes: B64C 27/20 Rotorcraft characterised by having shrouded rotors, e.g. flying platforms
• CPC Class Codes: B64C 7/00 Structures or fairings not otherwise provided for
• CPC Class Codes: G01S 1/08 Systems for determining direction or position line

Abstract

A rotor hub fairing system includes an upper hub fairing, a lower hub fairing and a shaft fairing therebetween. The rotor hub fairing system is attached to the counter-rotating, coaxial rotor system through a bearing arrangement such that the shaft fairing may be positioned at an azimuthal position about the main rotor axis of rotation relative the airframe by a de-rotation system. The de-rotation system controls the position of the shaft fairing about the axis of rotation such that the shaft fairing is prevented from rotating freely in unison with either shaft as may otherwise result during some flight regimes.

Claims

1. A fairing system comprising:

a shaft fairing mounted for rotation about an axis of rotation; and

a de-rotation system mounted to said shaft fairing to control a rotation of said shaft fairing about said axis of rotation.

2. The system as recited in claim 1, further comprising:

an upper hub fairing defined about said axis; and

a lower hub fairing defined about said axis, said shaft fairing mounted for relative movement between said upper hub fairing and said lower hub fairing.

3. The system as recited in claim 1, wherein said de-rotation system comprises:

a housing mounted to said shaft fairing;

a gear train supported by said housing;

an upper belt engaged with said gear train and an upper drive member which rotates about said axis of rotation; and

a lower belt engaged with said gear train and a lower drive member which rotates about said axis of rotation in a direction opposite said upper drive member.

4. The system as recited in claim 3, wherein said gear train further comprises:

an upper pulley engaged with said upper belt;

an upper gear mounted for rotation with said upper pulley;

a lower pulley engaged with said lower belt;

a lower gear mounted for rotation with said lower pulley; and

an idler gear meshingly engaged with said upper gear and said lower gear.

5. The system as recited in claim 4, wherein said upper pulley and said lower pulley are rotatable about a first gear train axis of rotation generally parallel to said axis of rotation, said idler gear defined about a second gear train axis of rotation generally transverse to said first gear train axis of rotation.

6. The system as recited in claim 4, wherein said upper belt is engaged with said upper pulley and said upper drive member, and said lower belt is engaged with said lower pulley and said lower drive member through a frictional force which provides self-aligning of the shaft fairing above a predetermined airspeed.

7. The system as recited in claim 1, wherein said de-rotation system comprises:

an upper plate which rotates about said axis of rotation;

a lower plate which rotates about said axis of rotation in a direction opposite said upper drive member;

a drive cone assembly engaged with said upper plate and said lower plate; and

a stationary support ring assembly mounted to said drive cone assembly, said shaft fairing mounted to said stationary support ring assembly.

8. The system as recited in claim 7, wherein said upper drive plate includes a beveled surface and said lower drive plate includes a beveled surface which faces said upper drive plate beveled surface.

9. The system as recited in claim 8, wherein said beveled surfaces each includes a roughened surface.

10. The system as recited in claim 8, wherein said upper drive cone assembly includes a multitude of shaft-mounted beveled cones each engaged between said beveled surfaces.

11. The system as recited in claim 10, wherein each of said beveled cones includes an elastomeric surface.

12. The system as recited in claim 10, wherein a shaft of each of said shaft-mounted beveled cones are received within said stationary support ring assembly along an axis generally transverse to said axis of rotation.

13. The system as recited in claim 10, wherein a shaft of each of said shaft-mounted beveled cones are received within a bearing mounted to said stationary support ring assembly.

14. The system as recited in claim 1, wherein said de-rotation system comprises:

a variable torque generator system having an inner support structure which rotates about said axis or rotation and an outer support structure which is mounted to said shaft fairing;

a sensor system which senses a position of said shaft fairing; and

a controller in communication with said variable torque generator system and said sensor system, said controller operable to control said variable torque generator system in response to said sensor system to position said shaft fairing about said axis of rotation.

15. The system as recited in claim 14, wherein said variable torque generator system comprises:

an electromagnetic torque generator which rotates about said axis of rotation;

16. The system as recited in claim 14, wherein said variable torque generator system comprises:

an upper electromagnetic torque generator which rotates about said axis of rotation;

a lower electromagnetic torque generator which rotates about said axis of rotation in a direction opposite said upper electromagnetic torque generator.

17. The system as recited in claim 14, wherein said variable torque generator system is mounted to a bearing.

18. A rotor hub fairing system for a counter rotating coaxial rotor system comprising:

an upper hub fairing defined about a rotor axis of rotation;

a lower hub fairing defined about said rotor axis of rotation;

a shaft fairing mounted between said upper hub fairing and said lower hub fairing for rotation about said rotor axis of rotation;

a passive de-rotation system mounted to said shaft fairing to minimize uncontrolled rotation of said shaft fairing about said axis of rotation.

19. The system as recited in claim 18, wherein said de-rotation system comprises:

a housing mounted to said shaft fearing;

an upper belt engaged with said gear train and an upper drive member which rotates about said axis of rotation;

a lower belt engaged with said gear train and a lower drive member which rotates about said axis of rotation in a direction opposite said upper drive member an upper pulley mounted for rotation relative said housing, said upper pulley engaged with said upper belt;

an upper gear mounted for rotation with said upper pulley;

a lower pulley mounted for rotation relative said housing, said lower pulley engaged with said lower belt;

a lower gear mounted for rotation with said lower pulley; and

an idler gear mounted for rotation relative said housing, said idler gear meshingly engaged with said upper gear and said lower gear.

20. The system as recited in claim 18, wherein said de-rotation system comprises:

an upper plate which rotates about said axis of rotation;

a lower plate which rotates about said axis of rotation in a direction opposite said upper drive member;

a drive cone assembly engaged with said upper plate and said lower plate;

a stationary support ring assembly mounted to said drive cone assembly, said shaft fairing mounted to said stationary support ring assembly.

21. A rotor hub fairing system for a counter rotating coaxial rotor system comprising:

an upper hub fairing defined about a rotor axis of rotation;

a lower hub fairing defined about said rotor axis of rotation;

a shaft fairing mounted between said upper hub fairing and said lower hub fairing for rotation about said rotor axis of rotation;

an active de-rotation system mounted to said shaft fairing to azimuthally position said shaft fairing about said axis of rotation.

22. The system as recited in claim 21, wherein said de-rotation system comprises:

a variable torque generator system having an inner support structure which is mounted to an inner race of a bearing which supports said rotor system, said inner support structure operable to rotate about said main rotor axis or rotation with said rotor system and an outer support structure mounted to an outer race of said bearing and said shaft fairing;

a sensor system which senses a position of said shaft fairing; and

a controller in communication with said variable torque generator system and said sensor system, said controller operable to control said variable torque generator system in response to said sensor system to position said shaft fairing about said main rotor axis of rotation.

23. The system as recited in claim 22, wherein said controller is in communication with a flight control system.