Rotor for a hover-capable aircraft

Patent metadata

Field	Value
Publication number	US-11319061-B2
Application number	US-201816621178-A
Country	US
Kind code	B2
Filing date	Jun 28, 2018
Priority date	Jun 30, 2017
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

A rotor for an aircraft is described that comprises: a hub rotatable about an axis and, in turn, comprising a plurality of blades; a mast connectable to a drive member of the aircraft and connected to the hub to drive the hub in rotation about the axis; and damping means to dampen the transmission of vibrations to the mast in a plane orthogonal to the axis; the damping means comprising at least a first mass and a second mass that can eccentrically rotate about the axis with a first and a second speed of rotation, respectively; the first mass and second mass are operatively connected to the mast to generate, respectively, a first and a second damping force on the mast having a main component in a direction radial to the axis; the rotor comprises a transmission unit, which is interposed between the mast and the first and second masses so as to drive the first and second masses in rotation.

First claim

The invention claimed is:

1. A rotor ( 3 , 3 ′, 3 ′″) for a hover-capable aircraft ( 1 ), comprising:
a hub ( 5 ) rotatable about a first axis (A) and, in turn, comprising a plurality of blades ( 9 );
a mast ( 6 ) connectable to a drive member of said aircraft ( 1 ) and operatively connected to said hub ( 5 ) to drive the hub ( 5 ) in rotation about said first axis (A);
damping means ( 15 ; 20 a , 20 b ; 21 a , 21 b ) to dampen the transmission of vibrations to said mast ( 6 ) in a plane orthogonal to said first axis (A);
said damping means ( 15 ; 20 a , 20 b ; 21 a , 21 b ) in turn comprising at least one first mass ( 20 a , 20 b ) and at least one second mass ( 21 a , 21 b ) that can eccentrically rotate about said first axis (A), respectively with a first and a second speed of rotation ((N−1)*Ω; −(N+1)*Ω) with respect to said mast ( 6 );
said first mass ( 20 a , 20 b ) and second mass ( 21 a , 21 b ) being operatively connected to said mast ( 6 ) to generate, respectively, a first and a second damping force on said mast ( 6 ) having a main component in a direction radial to said first axis (A);
said rotor ( 3 , 3 ′, 3 ′″) further comprising a transmission unit ( 19 , 19 ′, 19 ′″), which is functionally interposed between said mast ( 6 ) and said first and second masses ( 20 a , 20 b ; 21 a , 21 b ) so as to drive said first and second masses ( 20 a , 20 b ; 21 a , 21 b ) in rotation in opposite directions to each other;
characterized in that said first and second masses ( 20 a , 20 b ; 21 a , 21 b ) generate, in use, a resultant force with a sinusoidal course on said mast ( 6 );
said rotor ( 3 , 3 ′, 3 ′″) further comprising actuator means ( 80 a , 80 b , 81 a , 81 b ) selectively operable to vary the amplitude and phase of said resultant force;
said actuator means ( 80 a , 80 b , 81 a , 81 b ) comprising:
a drive member ( 82 );
a support element ( 66 ) operatively connected to one of said first and second masses ( 20 a , 20 b ; 21 a , 21 b ) and rotatable with respect to said mast ( 6 ); and
a further transmission unit ( 65 , 67 ) that can be driven by said drive member ( 82 ) and designed to drive, in use, said support element ( 66 );
said further transmission unit ( 65 , 67 ) being configured so as to irreversibly transmit motion only from an output member ( 83 ) of said drive member ( 82 ) to said support element ( 66 ) and to prevent the transmission of motion in the opposite direction from said support element ( 66 ) to said drive member ( 82 );
said further transmission unit ( 65 , 67 ) comprising a worm screw ( 65 ) that can be operated by said drive member ( 82 ), and helical gear teeth ( 67 ) carried by said support element ( 66 ) and irreversibly meshing with said worm screw ( 65 );
said rotor ( 3 , 3 ′, 3 ′″) comprising, for each said first mass ( 20 a , 20 b ) and second mass ( 21 a , 21 b ), an associated casing ( 62 , 63 );
said associated casing ( 62 , 63 ) rotating integrally with said mast ( 6 ) and with said drive member ( 82 ) about said first axis (A), and at least partly housing said further transmission unit ( 66 , 67 );
the associated output member ( 83 ) rotating with respect to said casing ( 62 , 63 ) about a second axis (B) transversal to said first axis (A);
said support element ( 66 ) being mounted in a manner angularly integral with said casing ( 62 , 63 ) about said first axis (A).

2. A rotor according to claim 1 , characterized in that said transmission unit ( 19 ; 19 ′; 19 ′″) comprises a first output member ( 30 , 68 ; 98 c , 98 d , 68 ) connected to said first mass ( 20 a , 20 b ) and at least a second output member ( 40 , 68 ; 98 a , 98 b , 68 ) connected to said second mass ( 21 a , 21 b );
said transmission unit ( 19 ; 19 ′) being configured so as to drive said first output member ( 30 , 68 ; 98 c , 98 d , 68 ) in rotation with a third angular speed associated with said first angular speed ((N−1)Ω) and in a first direction, and said second output member ( 40 , 68 ; 98 a , 98 b , 68 ) with a fourth angular speed associated with said second angular speed (−(N+1)*Ω) and in a second direction opposite to said first direction.

3. A rotor according to claim 2 , characterized in that said transmission unit ( 19 , 19 ′, 19 ′″) comprises:
a first stage ( 25 ) functionally interposed between said mast ( 6 ) and said at least one first mass ( 20 a , 20 b ); and
a second stage ( 26 ) functionally interposed between said first stage ( 25 ) and at least one said second mass ( 21 a ; 21 b ).

4. A rotor according to claim 3 , characterized in that said first and second stages ( 25 , 26 ) comprise a first and a second epicyclic train, respectively;
a first and a second sun gear ( 29 , 45 ) of said first and second epicyclic trains defined by said first and second stages ( 25 , 26 ) being angularly integral about said first axis (A) with said first and second masses ( 20 a , 20 b ; 21 a , 21 b ), respectively;
said first sun gear ( 29 ) being further angularly integral with a second ring gear ( 41 ) of said second epicyclic train defined by said second stage ( 26 );
said first and second epicyclic trains defined by said first and second stages ( 25 , 26 ) further comprising:
respective first and second planet gears ( 33 , 35 ; 46 , 48 );
a common planet-gear carrier ( 28 ), about which said first and second planet gears ( 33 , 37 ; 46 , 48 ) rotate and which is connected to a fuselage ( 2 ) of said aircraft ( 1 );

said first planet gears ( 33 , 35 , 37 ) meshing with said first sun gear ( 29 ) and with a first ring gear ( 27 );
said second planet gears ( 46 , 48 ) meshing with said second sun gear ( 45 ) and with said second ring gear ( 41 ).

5. A rotor according to claim 1 , characterized in that said first speed of rotation is equal to (N−1)*Ω and said second speed of rotation is equal to −(N+1)*Ω, where N is the number of said blades ( 9 ) and Ω is the speed of rotation of said mast ( 6 ) in a reference system integral with said fuselage ( 2 );
said first mass ( 20 a , 20 b ) being rotatable in the same direction as said mast ( 6 ) and with respect to said mast ( 6 ) with said first angular speed ((N−1)*Ω);
said second mass ( 21 a , 21 b ) being rotatable in the opposite direction to said mast ( 6 ) and with respect to said mast ( 6 ) with said second angular speed ((N+1)*Ω).

6. A rotor according to claim 1 , characterized in that said actuator means ( 80 a , 80 b , 81 a , 81 b ) are selectively operable to vary a first angle between said first masses ( 20 a , 20 b ) and/or a second angle between said second mass ( 21 a , 21 b ) with respect to said first axis (A).

7. A rotor according to claim 1 , characterized in that said first and second masses ( 20 a , 20 b ; 21 a , 21 b ) are movable along a direction radial to said first axis (A) with respect to said mast ( 6 ), and make contact with respective guides ( 23 ′) rotating integrally with said mast ( 6 ) about said first axis (A).

8. A rotor according to claim 1 , characterized in that it comprises a flow conveyor ( 10 ) connected to said hub ( 5 ) and designed to direct the airflow generated, in use, from the rotation of said blades ( 9 ) according to a predetermined path;
said first and second masses ( 20 a , 20 b ; 21 a , 21 b ) being housed inside said flow conveyor ( 10 );
said rotor ( 3 , 3 ′) being characterized in that said first and second epicyclic trains defining said first and second stages ( 25 , 26 ; 90 a , 90 b , 90 c , 90 d ) are housed inside said

Assignees

• Leonardo Spa

Inventors

• Colombo Attilio
• Bottasso Luigi
• Pisani Paolo
• Favarotto Andrea
• Colombo Dario
• Montagna Federico
• Regonini Roberto
• Braghin Francesco
• Cinquemani Simone

Classifications

• B64C27/08

  with two or more rotors · CPC title

• B64C2027/004

  using actuators, e.g. active systems · CPC title

• B64C27/32

  Rotors · CPC title

• B64C27/001 Primary

  Vibration damping devices · CPC title

• F16H1/06

  with parallel axes · CPC title