Beam for a rotorcraft rotor and rotorcraft rotor

Patent metadata

Field	Value
Publication number	US-10189563-B2
Application number	US-201414557995-A
Country	US
Kind code	B2
Filing date	Dec 2, 2014
Priority date	Dec 10, 2013
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

A beam for a rotorcraft rotor and particularly to a helicopter rotor. Said beam comprises a hub connection portion, a blade connection portion, a first flexure portion located between the hub connection portion and the blade connection portion and having a bending stiffness about a first axis which is orthogonal to the longitudinal axis of the blade, said bending stiffness being smaller than that of the hub connection portion and that of the blade connection portion and a shear portion located between the hub connection portion and the blade connection portion and having a shear stiffness parallel to a second axis which is orthogonal to the longitudinal axis of the blade and non-parallel to the first axis. Said shear stiffness is smaller than that of the hub connection portion and that of the blade connection portion.

First claim

What is claimed is:

1. A beam for attaching a blade to a hub of a rotor for a rotorcraft, the blade having a longitudinal axis extending radially from a rotation axis of the hub, the beam comprising:
a hub connection portion for connecting the beam to the hub of the rotor;
a blade connection portion for connecting the beam to the blade of the rotor;
a first flexure portion located between the hub connection portion and the blade connection portion and adapted to bend about a first bending axis orthogonal to a longitudinal axis of the blade, a first bending stiffness of the first flexure portion being smaller than a bending stiffness of the hub connection portion and smaller than a bending stiffness of the blade connection portion;
a second flexure portion located between the hub connection portion and the blade connection portion and adapted to bend about a second bending axis, wherein the second bending axis is orthogonal to the longitudinal axis of the blade and non-parallel to the first bending axis, a second bending stiffness of the second flexure portion being smaller than the first bending stiffness of the first flexure portion;
a shear portion located between the hub connection portion and the blade connection portion and adapted to rotate about a shear axis, wherein the shear axis is orthogonal to the first bending axis and parallel to one of the rotation axis of the hub or the second bending axis of the blade;
at least one slot-shaped groove extending into the shear portion and at least a part of the second flexure portion in a direction parallel to one of the rotation axis of the hub or the first bending axis of the blade, or a plane through the longitudinal axis of the blade and orthogonal to one of the rotation axis of the hub or the first bending axis of the blade;
wherein the slot-shaped groove reduces a shear stiffness of the shear portion to be smaller than a shear stiffness of the hub connection portion and a shear stiffness of the blade connection portion.

2. The beam according to claim 1 , wherein the first flexure portion is closer to the hub connection portion than the shear portion, or vice versa.

3. The beam according to claim 1 , wherein at least a part of the first flexure portion forms at least a part of the shear portion.

4. The beam according to claim 1 , wherein the first flexure portion is a flap portion and the first bending stiffness is a flap stiffness, the first bending axis being a flap axis orthogonal to the rotation axis of the hub; or the first flexure portion is a lead/lag portion and the first bending stiffness is a lead/lag stiffness and the first bending axis is a lead/lag axis parallel to the rotation axis of the hub.

5. The beam according to the claim 1 , wherein:
if the first flexure portion is a flap portion, the second flexure portion is a lead/lag portion and the second bending stiffness of the second flexure portion is a lead/lag stiffness, a lead/lag bending axis being parallel to a third axis parallel to the rotation axis of the hub; or
if the first flexure portion is a lead/lag portion, the second flexure portion is a flap portion and the second bending stiffness of the second flexure portion is a flap stiffness, the flap axis being parallel to the third axis orthogonal to the rotation axis of the hub.

6. The beam according to claim 1 , wherein the second flexure portion is closer to the hub connection portion than the shear portion, or vice versa.

7. The beam according to claim 1 , further comprising a torsion portion located between the hub connection portion and the blade connection portion and having a torsion stiffness about the longitudinal axis of the blade, the torsion stiffness being smaller than a torsion stiffness of the hub connection portion and a torsion stiffness of the blade connection portion and a torsion stiffness of the first flexure portion.

8. The beam according to the claim 7 , wherein at least a part of the shear portion forms at least a part of the torsion portion.

9. The beam according claim 1 , wherein the blade connection portion is linked to a bearing via a rod or tube having a bending stiffness and shear stiffness being greater than the bending stiffness and shear stiffness of the hub connection portion and blade connection portion.

10. The beam according to the claim 1 , wherein at least one of the slot-shaped grooves is filled with a material having a shear modulus smaller than a shear modulus of the material of the shear portion.

11. A rotorcraft rotor, the rotor having a number of rotor blades and a corresponding number of beams connecting each rotor blade with the hub; the rotorcraft rotor comprising:
the beam according to claim 1 ;
a hub with a first beam connection portion connected to the hub connection portion of the beam;
a blade with a second beam connection portion connected to the blade connection portion of the beam.

12. The rotorcraft rotor according to the claim 11 , wherein at least one of the first beam connection portion of the hub is attached to or integral with one of the hub connection portion or the second beam connection portion of the blade is attached to or integral with the blade connection portion.

13. A beam for attaching a blade to a hub of a rotorcraft, the beam comprising:
a hub connection portion defining an inboard end and connecting the beam to the hub of the rotor;
a blade connection portion defining an outboard end and connecting the beam to the blade of the rotor;
a first flexure portion located between the hub connection portion and the blade connection portion, wherein a first flexure portion height is less than a first flexure portion width and less than a hub connection portion height and a blade connection portion height, wherein the first flexure portion bends about a first bending axis being orthogonal to a longitudinal axis of the blade, a bending stiffness of the first flexure portion being smaller than a bending stiffness of the hub connection portion and smaller than a bending stiffness of the blade connection portion; and
a second flexure portion located between the hub connection portion and the blade connection portion, wherein
the second flexure portion bends about a second bending axis orthogonal to the longitudinal axis of the blade and non-parallel to the first bending axis, a second bending stiffness of the second flexure portion being smaller than the first bending stiffness of the first flexure portion,
a shear portion located between the hub connection portion and the blade connection portion, wherein the shear portion rotates about a shear axis orthogonal to the first bending axis and parallel to the second bending axis of the blade, a shear stiffness of the shear portion being smaller than a shear stiffness of the hub connection portion and a shear stiffness of the blade connection portion,
a plurality of parallel slots extending from an outer surface of the shear portion and at least a part of the second flexure portion inward in a direction of at least one of the second bending axis or orthogonal to the second bending axis.

14. The beam according to the claim 13 , wherein the first flexure portion height is orthogonal to the direction of the first bending axis and the first flexure portion height is less than a shear portion height.

15. The beam according to the claim 14 , wherein the first flexure portion has a cross sectional area less than a cross sectional area of the shear portion, the hub connection portion or the blade connection portion.

16. The beam according to claim 1 , wherein a second flexure portion width is less than a second f

Assignees

• Airbus Helicopters Deutschland GmbH

Inventors

• Buesing Moritz

Classifications

• B64C27/33 Primary

  having flexing arms · CPC title

• B64C27/35

  having elastomeric joints · CPC title