Flexbeam unit with at least one twisted flexbeam element

Patent metadata

Field	Value
Publication number	US-10005552-B2
Application number	US-201514722450-A
Country	US
Kind code	B2
Filing date	May 27, 2015
Priority date	May 28, 2014
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A flexbeam unit for a multi-blade rotor of a rotary wing aircraft, the flexbeam unit comprising a plurality of flexbeam elements defining a predetermined number of torsion elements that are connectable with associated rotor blades of the multi-blade rotor, at least one of the predetermined number of torsion elements comprising at least one flexbeam element having an associated longitudinal direction, the at least one flexbeam element comprising at least one twisted area in which the at least one flexbeam element is twisted in the associated longitudinal direction.

First claim

What is claimed is:

1. A flexbeam unit for a multi-blade rotor of a rotary wing aircraft, the flexbeam unit comprising:
a plurality of flexbeam elements defining a predetermined number of torsion elements that are connectable with associated rotor blades of the multi-blade rotor, at least one of the predetermined number of torsion elements comprising at least one flexbeam element having an associated longitudinal direction, the at least one flexbeam element having the form of a bar and comprising at least one stiff rotor hub connecting area adapted to be connected to an associated rotor hub of the multi-blade rotor and at least one stiff blade connecting area adapted to be connected to an associated rotor blade of the multi-blade rotor;
at least one twisted area in which the at least one flexbeam element is twisted in the associated longitudinal direction by a predetermined twist angle that is comprised in a range between 90° and 270°, the at least one twisted area being at least partially arranged between the at least one stiff rotor hub connecting area and the at least one stiff blade connecting area;
a multiplicity of fiber reinforced polymer layers, at least one of the multiplicity of fiber reinforced polymer layers extending from the at least one stiff rotor hub connecting area through the at least one twisted area to the at least one stiff blade connecting area; and
a multiplicity of separation layers arranged in the at least one twisted area between the multiplicity of fiber reinforced polymer layers.

2. The flexbeam unit according to claim 1 , wherein at least one twisted area comprises a cross section profile having an at least approximately invariable topology over the associated longitudinal direction in the twisted area.

3. The flexbeam unit according to claim 1 , wherein at least one twisted area defines a torsion-elastic and flexible area that is adapted to allow for backward and forward lead-lag motions, flapping movements and pitch angle control movements of an associated rotor blade of the multi-blade rotor, when the associated rotor blade is connected to the at least one flexbeam element.

4. The flexbeam unit according to claim 1 , wherein at least one flexbeam element is at least approximately helically shaped in the at least one twisted area.

5. The flexbeam unit according to claim 1 , wherein at least one of the multiplicity of fiber reinforced polymer layers comprises in the at least one stiff rotor hub connecting area and/or in the at least one stiff blade connecting area fiber plies having fibers that are oriented in an angle of at least approximately ±45° and/or 0° and/or 90° relative to the associated longitudinal direction.

6. The flexbeam unit according to claim 1 , wherein at least one of the multiplicity of fiber reinforced polymer layers is composed in the at least one twisted area of at least 60% of a laminate of unidirectional fiber plies.

7. The flexbeam unit according to claim 1 , wherein at least one of the multiplicity of fiber reinforced polymer layers comprises in the at least one twisted area at least two unidirectional fiber plies with at least one interlaced fabric ply.

8. The flexbeam unit according to claim 1 , wherein at least one of the multiplicity of separation layers comprises shear soft material, the shear soft material comprising an elastomer, a lubricant, polytetrafluoroethylene, polyurethane and/or air.

9. The flexbeam unit according to claim 1 , wherein at least one ramp-shaped connecting surface is provided between at least one of the multiplicity of fiber reinforced polymer layers and at least one of the multiplicity of separation layers.

10. The flexbeam unit according to claim 1 , wherein a first multiplicity of connecting plates is arranged in the at least one stiff rotor hub connecting area between the multiplicity of fiber reinforced polymer layers and/or that a second multiplicity of connecting plates is arranged in the at least one stiff blade connecting area between the multiplicity of fiber reinforced polymer layers.

11. The flexbeam unit according to claim 10 , wherein at least one of the first multiplicity and second multiplicity of connecting plates comprises a lateral side part that laterally extends at least partly from the at least one flexbeam element in a direction transverse to the associated longitudinal direction.

12. The flexbeam unit according to claim 1 , wherein at least one of the multiplicity of fiber reinforced polymer layers comprises in the at least one twisted area at least one longitudinal groove.

13. The flexbeam unit according to claim 1 , wherein at least one of the multiplicity of fiber reinforced polymer layers comprises in the at least one twisted area at least one longitudinal slot that extends through a thickness of the fiber reinforced polymer layer.

14. A flexbeam element for a multi-blade rotor of a rotary wing aircraft, the flexbeam element comprising:
a bar formed of a multiplicity of fiber reinforced polymer layers extending in a longitudinal direction between a stiff rotor hub connecting area adapted to be connected to an associated rotor hub of the multi-blade rotor and a stiff blade connecting area adapted to be connected to an associated rotor blade of the multi-blade rotor;
at least one twisted area along which the multiplicity of fiber reinforced polymers of the bar are twisted in the longitudinal direction by a predetermined twist angle between 90° and 270°, the at least one twisted area being at least partially arranged between the stiff rotor hub connecting area and the stiff blade connecting area; and
a multiplicity of separation layers arranged in the at least one twisted area between the multiplicity of fiber reinforced polymer layers, the multiplicity of separation layers extending continuously from the stiff rotor hub connecting area to stiff blade connecting area.

15. A flexbeam element for a rotary wing aircraft having a rotor hub and multiple rotor blades, the flexbeam element comprising:
a bar formed of a multiplicity of fiber reinforced polymer layers extending in a longitudinal direction between a stiff rotor hub connecting area adapted to be connected to the rotor hub and a stiff blade connecting area adapted to be connected to one of the multiple rotor blades;
a twisted area between the stiff rotor hub connecting area and the stiff blade connecting area along which the bar twists in the longitudinal direction by a twist angle between 90° and 270°;
a multiplicity of separation layers arranged in the twisted area of the bar and extending continuously from the stiff rotor hub connecting area to stiff blade connecting area, wherein one separation layer is provided between two adjacent fiber reinforced polymer to allow relative movement between each of the multiplicity of fiber reinforced polymer layers.

16. The flexbeam element according to claim 15 , wherein the twist angle is between 180° and 270°.

17. The flexbeam element according to claim 15 , wherein the twisted area of each of the multiplicity of fiber reinforced polymer layers is composed of at least three plies including two interlaced fiber fabric plies and one ply having at least 60% unidirectional fibers.

18. The flexbeam element according to claim 15 , wherein along the twisted area, at least one of the multiplicity of fiber reinforced polymer layers has a longitudinal slot that extends through a thickness of the fiber reinforced polymer layer.

19. The flexbeam element according to claim 15 , wherein along the twisted area, at least one of the multiplicity of fibe

Assignees

• Airbus Helicopters Deutschland GmbH

Inventors

• Buesing Moritz

Classifications

• B64C27/33 Primary

  having flexing arms · CPC title