Stiff inplane elastomeric rotorhead

Patent metadata

Field	Value
Publication number	US-9616996-B2
Application number	US-201313953292-A
Country	US
Kind code	B2
Filing date	Jul 29, 2013
Priority date	Jul 29, 2013
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

An aircraft rotor head is provided and includes a rotor hub including a central portion and radial arms extending outwardly from the central portion, blade retention yokes, each blade retention yoke being pivotably coupled to a corresponding one of the radial arms at one end and to a corresponding blade at another end and a lag restraint star rotatable about and translatable along the central portion. The lag restraint star is coupled to each of the blade retention yokes to facilitate uniform blade lead/lag and uniform blade coning.

First claim

What is claimed is:

1. An aircraft rotor head, comprising:
a rotor hub comprising a central portion having a longitudinal axis and radial arms extending outwardly from the central portion, each radial arm including a pair of radial arm elements and a bearing supportively disposed between the pair of radial arm elements;
blade retention yokes, each blade retention yoke being pivotably coupled to the bearing of a corresponding pair of radial arm elements of one of the radial arms at one end and to a corresponding blade at another end; and
a lag restraint star rotatable about the central portion and axially translatable between the pair of radial arm elements of each radial arm along the central portion with respect to the longitudinal axis, the lag restraint star being disposed radially between the central portion of the rotor hub and the blade retention yokes, and coupled to each of the blade retention yokes to facilitate uniform blade lead/lag and uniform blade coning.

2. The aircraft rotor head according to claim 1 , wherein the rotor hub is configured to prevent blade droop beyond a predefined angle.

3. The aircraft rotor head according to claim 1 , wherein
the bearing of each of the radial arms is a centering bearing supportively disposed between distal ends of the radial arm elements.

4. The aircraft rotor head according to claim 1 , wherein each blade retention yoke comprises a thrust bearing.

5. The aircraft rotor head according to claim 1 , wherein the lag restraint star is coupled to each of the blade retention yokes via a spherical bearing.

6. An aircraft rotor head, comprising:
a rotor hub comprising a central portion and radial arms extending outwardly from the central portion;
blade retention yokes, each blade retention yoke comprising a proximal portion, a distal portion coupled to a blade and an intermediate portion pivotably coupled to one of the radial arms; and
a lag restraint star comprising:
a first hub element rotatable about and translatable along the central portion;
a second hub element disposed adjacent to an exterior of the first hub element, the second hub element being rotatable about and along an exterior surface of the first hub element; and
receptacles extending outwardly from the second hub element, each receptacle comprising a tubular element and a bearing movably disposed within the tubular element and receptive of a proximal portion of one of the blade retention yokes.

7. The aircraft according to claim 6 , wherein the rotor hub comprises a number of the radial arms substantially uniformly arranged about the central portion, and wherein the lag restraint star comprises a corresponding number of the receptacles.

8. The aircraft according to claim 6 , wherein the rotor hub comprises a stopper to interfere with first hub element translation.

9. The aircraft according to claim 8 , wherein the tubular element of each receptacle is disposable in an offset orientation with respect to the one of the blade retention yokes with the stopper interfering with the first hub element translation.

10. The aircraft rotor head according to claim 6 , wherein each of the radial arms comprises:
a pair of radial arm elements; and
a centering bearing to which one of the blade retention yokes is coupled and which is supportively disposed between distal ends of the radial arm elements.

11. The aircraft rotor head according to claim 6 , wherein the proximal portion of each blade retention yoke comprises a thrust bearing.

12. The aircraft rotor head according to claim 6 , wherein each bearing comprises a spherical bearing.

13. A lag restraint star of an aircraft rotor head, comprising:
a first hub element rotatable about and translatable along a poloidal axis thereof;
a second hub element disposed adjacent to an exterior of the first hub element, the second hub element being rotatable about and along an exterior surface of the first hub element; and
receptacles extending outwardly from the second hub element, each receptacle comprising a tubular element and a bearing movably disposed within the tubular element and receptive of a blade retention assembly.

14. The lag restraint star according to claim 13 , wherein the first and second hub elements each comprises at least one or more of aluminum and titanium, and wherein the first and second hub elements each further comprises a low friction coating.

15. The lag restraint star according to claim 13 , wherein the first hub element comprises a uniball component.

16. The lag restraint star according to claim 13 , wherein the first hub element comprises:
a cylindrical interior surface; and
the exterior surface, which is at least partially spherical.

17. The lag restraint star according to claim 16 , wherein the second hub element comprises a convex interior surface to register with the exterior surface of the first hub element.

18. The lag restraint star according to claim 13 , wherein the receptacles are substantially uniformly arranged about the poloidal axis.

19. The lag restraint star according to claim 13 , wherein the receptacles extend radially outwardly from the second hub element.

20. The lag restraint star according to claim 13 , wherein the bearing of each receptacle is radially movably within the tubular element.

Assignees

• Sikorsky Aircraft Corp

Inventors

• Schmaling David N
• D'Anna Frank P

Classifications

• B64C27/54 Primary

  Mechanisms for controlling blade adjustment or movement relative to rotor head, e.g. lag-lead movement · CPC title

• B64C27/35

  having elastomeric joints · CPC title