Rotorcraft centrifugal force bearing

Patent metadata

Field	Value
Publication number	US-10836476-B2
Application number	US-201715666449-A
Country	US
Kind code	B2
Filing date	Aug 1, 2017
Priority date	Aug 1, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A centrifugal force (CF) bearing for a rotorcraft rotor assembly includes an inner-member, an outer-member, and an elastic member interposed between the inner- and outer-members. The outer-member includes an upper flange extension and a lower flange extension for location to and engagement with a grip. The upper flange extension is disposed over an upper surface portion of the elastic member, and the lower flange extension is disposed under a lower surface portion of the elastic member. The CF bearing is configured for attachment to a grip of the rotor assembly. The outer-member is configured to communicate mechanical loads (e.g., centrifugal force, lateral shear, vertical shear) from the grip to the yoke during operation of the rotor assembly.

First claim

What is claimed is:

1. A device, comprising:
a centrifugal force (CF) bearing for a rotorcraft, the CF bearing comprising:
a first member,
a second member,
and a third member, the first, second, and third members being aligned along a common pitch change axis, the third member interposed between the first member and the second member,
wherein the second member includes first protruding feature that extends in a direction toward the first member, the first protruding feature fitting within a recess in the third member and in contacting engagement with a surface of the third member that defines the recess,
the first member comprising an outer surface, the outer surface comprising an upper flange extension and a lower flange extension, the upper flange extension extending in a direction non-orthogonal to the common pitch change axis and being disposed over an upper portion of the third member, the lower flange extension disposed under a lower portion of the third member, wherein the upper flange extension has a distal end and a proximal end and wherein the distal end is closer to the second member than is the proximal end and the distal end is more radially spaced apart from the common pitch change axis than is the proximal end.

2. The device of claim 1 , wherein the second member comprises a first side having a first surface, and a second side having a second surface, the second side opposing the first side, wherein:
the first surface comprises a first protruding feature that extends in a direction toward the first member;
the second surface comprises a second protruding feature that extends in a direction away from the third member; and
the second protruding feature comprises a tapered profile.

3. The device of claim 2 , wherein the second protruding feature comprises a conical boss.

4. The device of claim 3 , wherein:
the first member has been configured for attachment to a rotor grip;
the second member has been configured for engagement with a rotor yoke;
the third member comprises an elastic material; and
the CF bearing has been configured to communicate a mechanical load from the rotor grip through the first member, the second member, and the third member to the rotor yoke.

5. The device of claim 4 , wherein the mechanical load comprises at least one of centrifugal force, lateral shear, or vertical shear.

6. The device of claim 5 , wherein a profile of the outer surface of the first member has been matched for positive engagement to the rotor grip.

7. The device of claim 6 , wherein:
the rotor grip has been one of a main rotor grip, a tail rotor grip, a prop-rotor grip, a tandem rotor grip, or a coaxial rotor grip; and
the rotor yoke has been a corresponding one of a main rotor yoke, a tail rotor yoke, a prop-rotor yoke, a tandem rotor yoke, or a coaxial rotor yoke.

8. The device of claim 1 , wherein:
the first member comprises at least one of steel or titanium;
the second member comprises 6Al-4V titanium; and
the third member comprises an elastomeric material.

9. A system, comprising:
a rotor assembly comprising:
a grip configured for attachment to a rotor blade;
a yoke having an opening therethrough, wherein the grip extends through the opening in the yoke; and
a centrifugal force (CF) bearing interposed between the grip and the yoke, wherein:
the CF bearing comprises an inner-member, an outer-member, and an elastic member interposed between the inner-member and the outer-member, respective center points of the inner-member, the outer-member, and the elastic member being aligned along a common axis, wherein the inner-member includes first protruding feature that extends in a direction toward the outer-member, the first protruding feature fitting within a recess in the elastic member and in contacting engagement with a surface of the elastic member that defines the recess, the inner-member further includes a second protruding feature that extends in a direction away from the outer-member, the second protruding feature fitting within a recess in the yoke;
the outer-member has been attached to a portion of the grip;
the outer-member comprises an upper flange in contact with an upper portion of the grip;
the upper flange has been disposed over an uppermost surface of the elastic member, the upper flange extending in a direction non-orthogonal to the common axis, the upper flange having a distal end and a proximal end, wherein the distal end is closer to the inner-member than is the proximal end and the distal end is more radially spaced apart from the common axis than is the proximal end;
the outer-member comprises a lower flange in contact with a lower portion of the grip; and
the lower flange has been disposed under a lowermost surface of the elastic member.

10. The system of claim 9 , wherein:
the second protruding feature has a continuously tapered profile that has been disposed in a tapered recess of the yoke.

11. The system of claim 10 , wherein the outer-member has been attached to the grip with an outer-clamp, and the second protruding feature has been located to the yoke by attachment of the inner-member with an inner-clamp.

12. The system of claim 9 , wherein:
a first outer surface profile of the upper flange has been matched for positive engagement to a first surface of the upper portion of the grip; and
the upper flange has been interposed between the first surface of the upper portion of the grip and the uppermost surface of the elastic member.

13. The system of claim 12 , wherein:
a second outer surface profile of the lower flange has been matched for positive engagement to a second surface of the lower portion of the grip; and
the lower flange has been interposed between the second surface of the lower portion of the grip and the lowermost surface of the elastic member.

14. The system of claim 9 , wherein:
the CF bearing has been configured to communicate a mechanical load from the grip through the outer-member to the yoke; and
the elastic member has been configured to communicate the mechanical load between the outer-member and the inner-member.

15. The system of claim 14 , wherein the mechanical load comprises at least one of centrifugal force, lateral shear, or vertical shear.

16. The system of claim 9 , wherein the rotor assembly has been one of a main rotor assembly, a tail rotor assembly, a prop-rotor assembly, a tandem rotor assembly, or a coaxial rotor assembly.

17. The system of claim 9 , wherein:
the outer-member comprises a first metal;
the elastic member comprises an elastomeric material; and
the inner-member comprises a second metal.

18. The system of claim 17 , wherein:
the first metal comprises steel or titanium;
the elastomeric material comprises vulcanized rubber; and
the second metal comprises 6Al-4V titanium.

19. A method, comprising:
operating a rotorcraft with an articulated main rotor blade, by
receiving a pilot control input; and
in response to the pilot control input, changing a configuration of a main rotor assembly of the rotorcraft;
wherein the main rotor assembly of the rotorcraft comprises:
a grip that has been attached to the articulated main rotor blade;
a yoke, wherein the grip extends through an opening in the yoke; and

transmitting a mechanical load from the grip to the yoke through a centrifugal force (CF) bearing that has been interposed between the grip and the yoke, wherein:
the CF bearing has an inner-member, an outer-member, and an elastic member disposed between the inner-member and the outer-member,

Assignees

• Textron Innovations Inc

Inventors

• Wiinikka Mark Adam
• Green Nathan Patrick
• Mccullough John R

Classifications

• B64C27/48

  Root attachment to rotor head · CPC title

• B64C27/37

  having articulated joints · CPC title

• B64C27/35 Primary

  having elastomeric joints · CPC title