Rotor dome, a rotor, and a rotorcraft

Patent metadata

Field	Value
Publication number	US-10040545-B2
Application number	US-201514939208-A
Country	US
Kind code	B2
Filing date	Nov 12, 2015
Priority date	Nov 14, 2014
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

A dome for a rotor of a rotorcraft, the dome comprising a cap extending radially from an axis of rotation in elevation towards a periphery and in azimuth over 360 degrees, the cap extending in thickness from a bottom face for facing a hub of the rotor towards a top face above the bottom face. At least one of the top and bottom faces is an undulating face that undulates at least in azimuth between the periphery and the axis of rotation in elevation, by including in azimuth along at least one internal circle a succession of bulges and of recesses.

First claim

What is claimed is:

1. A dome for a rotor of a rotorcraft, the dome comprising:
a cap extending radially and in an elevation direction from a center on an axis of rotation of the rotor towards a periphery of the cap, the periphery extending in an azimuth direction over 360 degrees, the cap extending in thickness from a bottom face for facing a hub of the rotor towards a top face above the bottom face, wherein at least one of the top and bottom faces is an undulating face undulating at least in the azimuth direction between the periphery and the axis of rotation by including in a succession of bulges and of recesses,
wherein an incident air stream from the rotor impacts in succession against each of the bulges and recesses during rotation of the dome about the axis of rotation in elevation,
wherein the undulating face has a plurality of top edges and a plurality of bottom edges extending away from the axis of rotation and in the elevation direction towards the periphery, each bottom edge being arranged in the azimuth direction between two top edges, the top edges defining a non-undulating top geometrical surface above a non-undulating bottom geometrical surface defined by the bottom edges, the undulating face undulating in the azimuth direction between the non-undulating top geometrical surface and the non-undulating bottom geometrical surface,
wherein the cap has a reference non-undulating middle geometrical surface arranged between the bottom face and the top face, and the cap has a thickness in elevation between each undulating face and the reference non-undulating middle geometrical surface that varies at least in the azimuth direction, the thickness varying continuously between a maximum thickness reached at each top edge and a minimum thickness reached at each bottom edge.

2. The dome according to claim 1 , wherein the top face is the undulating face.

3. The dome according to claim 1 , wherein the bottom face and the top face are symmetrical about the reference non-undulating middle geometrical surface.

4. The dome according to claim 1 , wherein at least one of the top and bottom edges extends radially.

5. The dome according to claim 1 , wherein the thickness at any position along the cap is determined by the following relationship between a given bottom edge and the given top edge following the given bottom edge:

e
⁡

(

r
,
θ

)

=

e
0

+

Δ
⁢

⁢

e
⁡

(
r
)

⁢

(

θ
-

θ
m

θ
M

-

θ
m

-

1
2

)

where e(r,θ) represents the thickness, e 0 is a constant representing a mean thickness, Δe represents a relationship giving a difference between a maximum thickness and a minimum thickness at a radial position “r”, “θ” represents an azimuth position between the given bottom edge and the given top edge, “θ m ” represents an azimuth position of the given bottom edge relative to a reference radius, and “θ M ” represents an azimuth position of the given top edge relative to the reference radius.

6. The dome according to claim 1 , wherein the thickness is determined at any position along the cap by the following relationship:

e
⁡

(

r
,
θ

)

=

e
0

+

Δ
⁢

⁢

e
⁡

(
r
)

⁢

sin
⁡

[

π
⁡

(

θ
-

θ
m

θ
M

-

θ
m

-

1
2

)

]

2

where e(r,θ) represents the thickness, e 0 is a constant representing a mean thickness, Δe represents a relationship giving a difference between a maximum thickness and a minimum thickness at a radial position “r”, “θ” represents an azimuth position between the given bottom edge and the given top edge, “θ m ” represents an azimuth position of the given bottom edge relative to a reference radius, and “θ M ” represents an azimuth position of the given top edge relative to the reference radius.

7. The dome according to claim 1 , wherein at least one of the top and bottom edges does not extend along a radius of the cap.

8. The dome according to claim 7

Assignees

• Airbus Helicopters

Inventors

• Alfano David
• Desvigne Damien
• Fukari Raphael

Classifications

• B64C7/00

  Structures or fairings not otherwise provided for · CPC title

• B64C2027/003

  mounted on rotor hub, e.g. a rotary force generator · CPC title

• B64C27/001

  Vibration damping devices · CPC title

• B64C27/04

  Helicopters · CPC title

• B64C27/32 Primary

  Rotors · CPC title