Rotorcraft rotor having a flapping abutment mechanism, and a rotorcraft

Patent metadata

Field	Value
Publication number	US-9834304-B2
Application number	US-201514608656-A
Country	US
Kind code	B2
Filing date	Jan 29, 2015
Priority date	Jan 31, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A rotor carrying a plurality of lift assemblies, each having a retention and mobility member. An abutment mechanism of a lift assembly includes an abutment track arranged on the retention and mobility member and a single cylindrical abutment that is movable in pivoting about a movement axis, said abutment extending over a height in elevation and also over a length and over a width. The length is greater than said width, and said height is greater than said length. A fly-weight is secured to pivot with said abutment, and a return spring exerts a force on said fly-weight.

First claim

What is claimed is:

1. A rotor for a rotorcraft, the rotor having a hub carrying a plurality of lift assemblies, the hub having at least one plate, each lift assembly having a retention and mobility member connected to the at least one plate of the hub, the rotor having a single abutment mechanism for each lift assembly to limit upward and downward flapping movement of the lift assembly, wherein each abutment mechanism for a lift assembly comprises:
an abutment track arranged on a rear face of the retention and mobility member facing an axis of rotation in elevation of the rotor;
a single cylindrical abutment hinged to the at least one plate of the hub by hinge means to be movable solely in pivoting about a movement axis between an engagement position in which the flapping movement is limited by shape interference between the cylindrical abutment and the abutment track under at least one predetermined condition, and a disengagement position in which the movement is not limited by the cylindrical abutment, the cylindrical abutment extending over a height in elevation along said movement axis and over a length along a longitudinal axis that is arranged substantially parallel to a span direction of the lift assembly when in the engagement position, and over a width along a transverse axis perpendicular to the movement axis and to the longitudinal axis, the length being greater than the width, the height being greater than the length;
a fly-weight constrained to pivot with the cylindrical abutment and laterally offset relative to the longitudinal axis when in the engagement position; and
a return spring exerting a force on the abutment mechanism to tend to position the cylindrical abutment in the engagement position.

2. A rotor according to claim 1 , wherein the retention and mobility member is a laminated abutment.

3. A rotor according to claim 1 , wherein the rear face extends over an elevation distance along an axis parallel to the movement axis, and the elevation distance is less than or equal to the height of the cylindrical abutment.

4. A rotor according to claim 1 , wherein the abutment mechanism includes longitudinal clearance between the abutment track and the abutment in the engagement position.

5. A rotor according to claim 1 , wherein the rear face represents the abutment track.

6. A rotor according to claim 1 , wherein the abutment track includes a removable wear member removably fastened to the rear face.

7. A rotor according to claim 1 , wherein the hinge means comprise a tube secured to the cylindrical abutment, the tube being hinged to the at least one plate of the hub.

8. A rotor according to claim 7 , wherein the fly-weight is secured to the tube.

9. A rotor according to claim 1 , wherein the return spring extends between the fly-weight and the at least one plate of the hub.

10. A rotor according to claim 1 , wherein the cylindrical abutment comprises a cylindrical body having a rear portion adjacent to a front portion respectively facing the axis of rotation and the abutment track when in the engagement position, the front portion having a base with a periphery that is rounded in part.

11. A rotor according to claim 10 , wherein the front portion has a semicircular base.

12. A rotor according to claim 1 , wherein the at least one plate of the hub includes a bottom plate and a top plate, and the cylindrical abutment is arranged between the bottom plate and the top plate.

13. A rotor according to claim 12 , wherein the fly-weight is arranged under the bottom plate and/or over the top plate.

14. A rotorcraft, wherein the rotorcraft includes a rotor according to claim 1 .

15. A rotor according to claim 1 , wherein the movement axis of the cylindrical abutment is parallel to the axis of rotation of the rotor.

16. A rotor for a rotorcraft comprising:
a hub having a plate;
a lift assembly;
a retention and mobility member connecting the lift assembly to the plate of the hub; and
a single abutment mechanism comprising:
an abutment track arranged on a rear face of the retention and mobility member, the abutment track facing an axis of rotation of the rotor,
a single cylindrical abutment element connected to the plate of the hub by a hinge for movement solely in pivoting about a movement axis between an engagement position and a disengagement position, the abutment element extending from an upper distal end to a lower distal end along the movement axis to define a height of the abutment element therebetween, the abutment element extending from a front portion to a rear portion along a longitudinal axis to define a length therebetween, the longitudinal axis being parallel to a span direction of the lift assembly when in the engagement position, and the abutment element extending between two opposed side faces along a transverse axis perpendicular to the movement axis and to the longitudinal axis to define a width therebetween, wherein the length is greater than the width, and the height is greater than the length,
a fly-weight connected to and constrained to pivot with the abutment element, the fly-weight being laterally offset relative to the longitudinal axis when in the engagement position, the fly-weight configured to tend to position the abutment element in the disengagement position in response to rotation of the rotor, and
a return spring exerting a force on the abutment mechanism to tend to position the abutment element in the engagement position,
wherein the front portion of the abutment element is configured to contact the abutment track in the engagement position to limit upward and downward flapping movement of the lift assembly, and
wherein the abutment element in the disengagement position is configured to not limit flapping movement of the lift assembly.

17. A rotor according to claim 16 , wherein the movement axis of the abutment element is parallel with the axis of rotation of the rotor.

18. A rotor according to claim 16 , wherein the front portion of the abutment element has a rounded periphery.

19. A rotor according to claim 16 , wherein the plate of the hub is an upper plate;
wherein the hub has a lower plate, the retention and mobility member connecting the lift assembly to the lower plate of the hub, and the single abutment element connected to the upper plate of the hub by the hinge; and
wherein the abutment element is positioned between the upper and lower plates.

20. A rotor according to claim 16 , wherein the abutment element is positioned between the retention and mobility member and the axis of rotation of the rotor.

Assignees

• Airbus Helicopters

Inventors

• Massal Fabien

Classifications

• B64C27/322 Primary

  Blade travel limiting devices, e.g. droop stops · CPC title

• B64C27/35

  having elastomeric joints · CPC title