Blade fold Method and Apparatus for A Tilt Rotor Hub

• US 20190329867A1
• Filed: 04/26/2018
• Published: 10/31/2019
• Est. Priority Date: 04/26/2018
• Status: Active Grant

• Current Assignee: Bell Textron Rhode Island Inc. (Textron Inc)
• Original Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Inventors: CRAVENER, Kyle Thomas, SHIMEK, Glenn
• Granted Patent: US 10,703,461 B2
• Time in Patent Office: Days
• CPC Class Codes: B64C 11/06 for variable-pitch blades
• CPC Class Codes: B64C 11/28 Collapsible or foldable blades
• CPC Class Codes: B64C 11/30 Blade pitch-changing mechanisms
• CPC Class Codes: B64C 29/0033 the propellers being tiltable relative to the fuselage
• CPC Class Codes: B64U 30/293 Foldable or collapsible rotors or rotor supports
• CPC Class Codes: F16C 17/026 with helical grooves in the bearing surface to generate hydrodynamic pressure, e.g. herringbone grooves
• CPC Class Codes: F16C 2326/43 Aeroplanes; Helicopters

Abstract

A folding rotor blade assembly for an aircraft a yoke, an inboard beam coupled to the yoke, an inboard centrifugal force bearing coupled to the inboard beam, a grip coupled to the inboard beam, an outboard bearing housing coupled to the grip, and a rotor blade pivotally coupled to the grip by a blade fold bolt that is positioned outboard of the outboard bearing housing.

Claims

1. A folding rotor blade assembly for an aircraft, the folding rotor blade assembly comprising:

a yoke;

an inboard beam coupled to the yoke;

an inboard centrifugal force bearing coupled to the inboard beam;

a grip coupled to the inboard beam;

an outboard bearing housing coupled to the grip; and

a rotor blade pivotally coupled to the grip by a blade fold bolt that is positioned outboard of the outboard bearing housing.

2. The folding rotor blade assembly of claim 1, comprising a blade fold support coupled to the grip by the blade fold bolt.

3. The folding rotor blade assembly of claim 2, comprising a lock assembly coupled to the blade fold support and configured to lock the rotor blade in an extended position.

4. The folding rotor blade assembly of claim 3, wherein:

the rotor blade comprises a blade tang that extends from an inboard end of the rotor blade toward the yoke; and

the lock assembly includes a tab that, in a first position, abuts the blade tang and prevents the rotor blade from rotating relative to the blade fold support and, in a second position, allows the rotor blade to rotate relative to the blade fold support.

5. The folding rotor blade assembly of claim 2, wherein the blade fold bolt passes through the blade fold support, the rotor blade, and the grip.

6. The folding rotor blade assembly of claim 1, comprising:

an inboard bearing assembly coupled between the inboard beam and the yoke;

a yoke flexure extending from the yoke and coupled to the outboard bearing housing; and

an outboard bearing assembly coupled between the outboard bearing housing and the yoke flexure.

7. The folding rotor blade assembly of claim 6, wherein the yoke flexure and the outboard bearing assembly are coupled together by a spindle.

8. The folding rotor blade assembly of claim 6, wherein the inboard bearing assembly comprises an inboard shear bearing and the inboard centrifugal force bearing.

9. The folding rotor blade assembly of claim 6, wherein the outboard bearing assembly comprises an outboard shear bearing.

10. The folding rotor blade assembly of claim 8, wherein the inboard shear bearing is coupled to the inboard centrifugal force bearing.

11. A folding rotor blade assembly for an aircraft, the folding rotor blade assembly comprising:

a yoke connected to and axially aligned with a hub spring assembly;

an inboard beam housing an inboard centrifugal force bearing, the inboard beam connected to the yoke;

a grip connected at a first end to the inboard beam;

an outboard bearing housing connected to a second end of the grip;

an outboard bearing assembly coupled between the outboard bearing housing and the second end of the grip;

a blade fold support connected to the grip and the outboard bearing housing; and

a rotor blade connected to the grip at a pivotal connection positioned outboard of the outboard bearing assembly.

12. The folding rotor blade assembly of claim 11, wherein the pivotal connection comprises a blade fold bolt that passes through the rotor blade and the grip.

13. The folding rotor blade assembly of claim 12, comprising a lock assembly coupled to the blade fold support and configured to lock the rotor blade in an extended position.

14. The folding rotor blade assembly of claim 13, wherein:

the rotor blade comprises a blade tang that extends from an inboard end of the rotor blade toward the yoke; and

the lock assembly includes a tab that in a first position abuts the blade tang and prevents the rotor blade from rotating relative to the blade fold support and in a second position allows the rotor blade to rotate relative to the blade fold support.

15. The folding rotor blade assembly of claim 13, comprising:

an inboard bearing assembly coupled between the inboard beam and the yoke;

a yoke flexure extending from the yoke and coupled to the outboard bearing housing; and

an outboard bearing assembly coupled between the outboard bearing housing and the yoke flexure.

16. A method comprising:

pitching a first rotor blade of a rotor blade assembly, the rotor blade assembly comprising;

an inboard bearing assembly comprising an inboard centrifugal force bearing and connected to a yoke and a grip;

an outboard bearing assembly connected to the yoke and the grip;

a blade fold support connected to the grip; and

wherein the first rotor blade is pivotally connected to the blade fold support via a blade fold bolt, the blade fold support configured to prevent a pivoting rotation of the first rotor blade relative to the yoke when the blade fold support is in a locked configuration, the blade fold bolt providing a pivot axis outboard of the outboard bearing assembly;

unlocking the first rotor blade to allow the first rotor blade to pivot relative to the yoke; and

rotating the first rotor blade about the pivot axis.

17. The method of claim 16, wherein the rotor blade assembly further comprises a lock assembly attached to the blade fold support.

18. The method of claim 17, wherein the unlocking comprises moving a tab of the lock assembly to allow the first rotor blade to pivot relative to the yoke.

19. The method of claim 16, comprising pitching and unlocking a second rotor blade.

20. The method of claim 19, wherein the first and second rotor blades are rotated to be generally parallel with each other and a third rotor blade.