Rotor blade non-counterbored retention assembly via a sliding clamped bushing

Patent metadata

Field	Value
Publication number	US-11999472-B2
Application number	US-202117518370-A
Country	US
Kind code	B2
Filing date	Nov 3, 2021
Priority date	Nov 3, 2021
Publication date	Jun 4, 2024
Grant date	Jun 4, 2024

Abstract

A rotor blade retention assembly includes a central hub, a rotor blade including an upper outer surface, a lower outer surface, a blade hole, and a proximal end coupled to the central hub, a strap member extending along a portion of the rotor blade such that a distal end receiving portion extends into the blade hole, and a retainer assembly disposed within the blade hole and coupled to the strap member. The retainer assembly includes an upper bushing and a lower bushing slidably disposed within the blade hole. The upper bushing includes a counterbored portion. The retainer assembly also includes an outboard blade pin disposed within the distal end receiving portion and includes a blade pin inner cavity.

First claim

What is claimed is:

1. A rotor blade retention assembly comprising:
a central hub,
a rotor blade comprising an upper outer surface, a lower outer surface, a blade hole, and a proximal end coupled to the central hub;
a strap member extending along a portion of the rotor blade such that a distal end receiving portion of the strap member extends into the blade hole; and
a retainer assembly disposed within the blade hole and coupled to the strap member, the retainer assembly comprising:
an upper bushing slidably disposed within the blade hole and extending between the strap member and the upper outer surface of the rotor blade, the upper bushing comprising an upper counterbored portion,
a lower bushing slidably disposed within the blade hole and extending between the strap member and the lower outer surface of the rotor blade,
an outboard blade pin disposed within the distal end receiving portion of the strap member, the outboard blade pin comprising a blade pin inner cavity,
a first fastener disposed within the upper counterbored portion, and
a second fastener extending through the blade pin inner cavity and coupled to the first fastener such that the first fastener, the outboard blade pin, and the second fastener cooperatively clamp the lower bushing and the upper bushing to the strap member.

2. The rotor blade retention assembly of claim 1 , further comprising a protective layer disposed within the blade hole,
where a first portion of the protective layer is disposed between an inner wall of the blade hole and the upper bushing and extends from the strap member to the upper outer surface, and
wherein a second portion of the protective layer is disposed between the inner wall of the blade hole and the lower bushing and extends from the strap member to the lower outer surface.

3. The rotor blade retention assembly of claim 1 , wherein the first fastener comprises:
a cap portion,
a lower portion, and
a fastener cavity extending through the cap portion and the lower portion.

4. The rotor blade retention assembly of claim 3 , wherein the second fastener is a threaded fastener extending into the fastener cavity and threadedly coupled to the lower portion of the first fastener.

5. The rotor blade retention assembly of claim 4 , wherein:
the receiving portion further comprises an inner mating component surface, and
the cap portion is configured to compress the upper bushing via the second fastener such that the upper bushing clamps the inner mating component surface and reduces a gap between the upper bushing and the inner mating component surface.

6. The rotor blade retention assembly of claim 3 , wherein the first fastener is disposed within the upper counterbored portion such that the cap portion remains below the upper outer surface of the rotor blade.

7. The rotor blade retention assembly of claim 3 , wherein a top portion of the outboard blade pin is disposed between the lower portion of the first fastener and the upper bushing.

8. The rotor blade retention assembly of claim 1 , wherein:
the rotor blade further comprises a blade inner cavity that extends along an interior of the rotor blade, and
the strap member is disposed within the blade inner cavity.

9. The rotor blade retention assembly of claim 1 , wherein the retainer assembly transfers a load from the retainer assembly to the strap member.

10. A retainer assembly for use in a rotor blade retention assembly having a retainer cavity, the retainer assembly comprising:
an upper bushing slidably disposed within the retainer cavity, the upper bushing comprising an upper counterbored portion;
a lower bushing slidably disposed within the retainer cavity, the upper bushing and the lower bushing cooperating to define a bushing inner cavity;
an outboard blade pin disposed within the bushing inner cavity, the outboard blade pin comprising a blade pin inner cavity;
a first fastener disposed within the upper counterbored portion; and
a second fastener extending through the blade pin inner cavity and coupled to the first fastener such that the first fastener, the outboard blade pin, and the second fastener are configured to cooperatively clamp the lower bushing and the upper bushing to a spool disposed therebetween.

11. The retainer assembly of claim 10 , wherein the first fastener comprises:
a cap portion,
a lower portion, and
a fastener cavity extending through the cap portion and the lower portion.

12. The retainer assembly of claim 11 , wherein the first fastener is disposed within the upper counterbored portion such that the cap portion is disposed entirely within the retainer cavity.

13. The retainer assembly of claim 11 , wherein the second fastener is a threaded fastener extending into the fastener cavity and threadedly coupled to the lower portion of the first fastener.

14. The retainer assembly of claim 13 , wherein a top portion of the outboard blade pin is disposed between the upper bushing and the lower portion of the first fastener.

15. The retainer assembly of claim 14 , wherein the upper bushing and the lower bushing are configured to be clamped to the spool with the spool surrounding a blade pin body portion of the outboard blade pin.

16. The retainer assembly of claim 15 , wherein the cap portion is configured to compress the upper bushing via the second fastener such that the upper bushing clamps the spool and reduces a gap between the upper bushing and the spool.

17. The retainer assembly of claim 11 , wherein a diameter of the cap portion is greater than a diameter of the lower portion.

18. The retainer assembly of claim 10 , wherein:
the lower bushing comprises a lower counterbored portion,
the outboard blade pin comprises a base portion, and
wherein the base portion is disposed within the lower counterbored portion.

19. A method for installing a retainer assembly of a rotor blade retention assembly having a central hub, a rotor blade having a blade hole, a blade inner cavity and a proximal end coupled to the central hub, and a strap member disposed within the blade inner cavity and including a distal end receiving portion, the retainer assembly having an upper bushing with an upper counterbored portion, a lower bushing, and a bushing inner cavity, a first fastener, a second fastener, and an outboard blade pin including a blade pin inner cavity, the method comprising:
inserting the distal end receiving portion of the strap member into the blade hole,
inserting, after inserting the distal end receiving portion of the strap member into the blade hole, the upper bushing and the lower bushing into the blade hole;
inserting, after inserting the upper bushing and the lower bushing into the blade hole, the outboard blade pin into the bushing inner cavity and through the distal end receiving portion;
inserting the first fastener into the upper counterbored portion of the upper bushing;
inserting the second fastener through the blade pin inner cavity; and
coupling the first fastener to the second fastener such that the first fastener, the outboard blade pin, and the second fastener cooperatively clamp the lower bushing and the upper bushing to the strap member.

20. A rotor blade retention assembly comprising:
a central hub,
a rotor blade comprising an upper outer surface, a lower outer surface, a blade hole, and a proximal end coupled to the central hub;
a strap member extending along a portion of the rotor blade such that a distal end receiving portion of the strap member extends into the blade hole;
a reta

Assignees

• Lockheed Corp

Inventors

• Schuster Daniel George
• Tobin Evan S
• Schmaling David N

Classifications

• B64C27/10

  arranged coaxially · CPC title

• B64C27/48 Primary

  Root attachment to rotor head · CPC title

• B64C27/35 Primary

  having elastomeric joints · CPC title

• B64C27/26

  characterised by provision of fixed wings · CPC title

• B64C2027/8236

  including pusher propellers · CPC title