Hybrid yoke

Patent metadata

Field	Value
Publication number	US-10556676-B2
Application number	US-201815881980-A
Country	US
Kind code	B2
Filing date	Jan 29, 2018
Priority date	Jan 29, 2018
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

A hybrid yoke including a center and yoke arms connected to flexure arms. An inboard centrifugal force bearing assembly connects to the yoke arm and a grip and an outboard shear bearing assembly connects to the flexure arm and the grip. In use, the center and yoke arms carry the centrifugal force at a position inboard of the flexure arm.

First claim

What is claimed is:

1. A hybrid yoke for a rotorcraft, comprising:
a center yoke including a yoke arm, where the yoke arm is a unitary portion of the center yoke;
a flexure arm connected to the yoke arm, wherein the center yoke and the yoke arm are constructed of a metal and the flexure arm is constructed of a flexible composite material;
a centrifugal force (“CF”) joint positioned within the yoke arm proximate the center yoke and inboard of the flexure arm;
an inboard beam including a first tang and a second tang extending from a bridge, where the first tang is vertically aligned with the second tang;
a shaft extending from the bridge toward the center yoke;
a cavity in the bridge opposite the shaft, a CF bearing held by and between the cavity and the yoke arm;
a clamp plate attached to the yoke arm; and
an inboard shear bearing attached to the shaft and held by the clamp plate; and
an outboard bearing assembly coupled to the flexure arm and located outboard of the CF joint wherein the hybrid yoke is configured to connect to a rotor blade at the CF joint and the outboard bearing assembly, whereby in use a CF load path is from the rotor blade to the CF joint, the yoke arm, and the center yoke, and the CF load path does not include the flexure arm or the outboard bearing assembly or a grip.

2. The hybrid yoke of claim 1 , wherein the yoke arm further comprises a cut-out proximate the center yoke and the CF joint is positioned within the cut-out.

3. The hybrid yoke of claim 1 , wherein the yoke arm includes a CF fitting and the CF fitting is a unitary portion of the yoke arm.

4. The hybrid yoke of claim 1 , wherein the center yoke and the yoke arm further comprise weight pockets.

5. The hybrid yoke of claim 1 , further comprising:
a cut-out in the yoke arm; and
a CF fitting, where the CF fitting is a unitary portion of the yoke arm within the cut-out.

6. The hybrid yoke of claim 1 , further comprising:
a tab extending from the CF bearing engaged with a slot in the yoke arm.

7. The hybrid yoke of claim 1 , wherein the yoke arm further comprises:
a cut-out proximate the center yoke;
a CF fitting formed by the cut-out, where the CF fitting is a unitary portion of the yoke arm within the cut-out; and
a weight pocket.

8. The hybrid yoke of claim 1 , wherein the flexure arm is connected to the yoke arm by a double shear connection.

9. A rotor blade assembly of a rotorcraft, comprising:
a center yoke including a central aperture;
a drive shaft connected to the center yoke at the central aperture;
a yoke arm, formed by the center yoke, extending radially from the central aperture;
a flexure attached to the yoke arm opposite the center yoke;
a centrifugal force (“CF”) bearing connected to the yoke arm inboard of the flexure;
a rotor blade connected to the CF bearing without a grip between the rotor blade and the CF bearing;
an outboard bearing assembly comprising an outboard shear bearing, the outboard bearing assembly connected to the flexure and the rotor blade;
an inboard beam including a first tang and a second tang extending from a bridge, where the first tang is vertically aligned with the second tang;
a shaft extending from the bridge toward the center yoke;
a cavity in the bridge opposite the shaft, the CF bearing held by and between the cavity and the yoke arm;
a clamp plate attached to the yoke arm;
an inboard shear bearing attached to the shaft and held by the clamp plate; and
a CF load path of the rotor blade assembly through the rotor blade, the CF bearing, the yoke arm, and the center yoke, wherein the CF load path does not include the flexure, the outboard bearing assembly, or the grip.

10. The rotor blade assembly of claim 9 , wherein the yoke arm further comprises a cut-out proximate the center yoke and the CF bearing is connected to the yoke arm in the cut-out.

11. The rotor blade assembly of claim 9 ,
wherein the CF bearing is centered between the cavity in the bridge and a conical cavity in the yoke arm when the CF bearing is under compression by a CF load created by rotation of the rotor blade assembly.

12. The rotor blade assembly of claim 9 , wherein the yoke arm further comprises:
a cut-out proximate the center yoke and the CF bearing extends through the cut-out;
a CF fitting formed in the cut-out; and
a weight pocket.

13. The rotor blade assembly of claim 9 , wherein the flexure is attached to the yoke arm by a double shear connection.

14. The rotor blade assembly of claim 9 , wherein the center yoke and the yoke arm are constructed of a metal and the flexure is constructed of a flexible composite material.

15. The rotor blade assembly of claim 9 , wherein the center yoke and the yoke arm are constructed of a metal and the flexure is constructed of a flexible composite material; and
the flexure is attached to the yoke arm by a double shear connection.

16. A hybrid yoke for a rotorcraft, comprising:
a center yoke including a yoke arm;
a flexure arm connected to the yoke arm, wherein the center yoke and the yoke arm are constructed of a metal and the flexure arm is constructed of a flexible composite material;
a cut-out in the yoke arm, inboard of the flexure arm, including a centrifugal force (“CF”) fitting;
a first curved surface formed in the CF fitting;
an inboard beam including a shaft extending from a bridge and a second curved surface in the bridge opposite the shaft;
a CF bearing held by and axially centered between the first curved surface and the second curved surface;
a clamp plate attached to the yoke arm;
an inboard shear bearing attached to the shaft and held by the clamp plate; and
an outboard bearing assembly connected to the flexure arm wherein the hybrid yoke is configured to connect to a rotor blade at the CF bearing and the outboard bearing assembly whereby in use a CF load path of the rotor blade is from the rotor blade to the CF bearing, to the yoke arm and the center yoke, and the CF load path does not include the flexure arm or the outboard bearing assembly or a grip.

17. The hybrid yoke of claim 16 , further comprising a slot in the first curved surface and a tab extending from the CF bearing engaged with the slot.

18. The hybrid yoke of claim 16 , wherein the inboard beam, the yoke arm, the center yoke, and the CF bearing carry a CF load upon rotation of the hybrid yoke.

19. The hybrid yoke of claim 16 , wherein the flexure arm is connected to the yoke arm by a double shear connection.

Assignees

• Bell Helicopter Textron Inc

Inventors

• Baldwin Tyler Wayne
• Cravener Kyle Thomas

Classifications

• B64C11/28

  Collapsible or foldable blades · CPC title

• B64C29/0033

  the propellers being tiltable relative to the fuselage · CPC title

• B64C27/33 Primary

  having flexing arms · CPC title

• B64C27/22

  Compound rotorcraft, i.e. aircraft using in flight the features of both aeroplane and rotorcraft · CPC title

• B64C27/35

  having elastomeric joints · CPC title