Aircraft

Patent metadata

Field	Value
Publication number	US-11891187-B2
Application number	US-201917414499-A
Country	US
Kind code	B2
Filing date	Nov 28, 2019
Priority date	Dec 21, 2018
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

An aircraft is described comprising: a support element; a shaft rotating about an axis; a pair of oblique rolling bearings mounted so as to couple the shaft to the support element rotatingly about the axis; the rolling bearings comprising: respective first races cooperating radially in contact with a first component defined by one from the support element and the shaft; respective second races cooperating radially in contact with a second component defined by the other from the support element and the shaft; and respective pluralities of rolling elements adapted to roll on the first and second races; the aircraft further comprises a pair of preloaded elastic members, which couple the first races to the first component respectively, axially and in an elastically yielding manner.

First claim

The invention claimed is:

1. An aircraft ( 1 ) comprising:
a fuselage ( 2 ) with a first longitudinal extension axis (A) between a nose ( 2 a ) and a tail portion ( 2 b ) opposite along said first longitudinal extension axis (A);
a pair of half-wings ( 3 ) extending in a cantilever fashion from respective opposite sides of said fuselage ( 2 ) and transversely to said first longitudinal extension axis (A);
a pair of nacelles ( 4 ); and
a pair of rotors ( 5 );

each said rotor ( 5 ) comprising, in turn:
a motor ( 6 );
a drive shaft ( 7 ) rotatable about a second axis (B);
a hub ( 8 ) dragged, in use, into rotation by said drive shaft ( 7 );
a plurality of blades ( 9 ), which are articulated on said hub ( 8 );

said aircraft ( 1 ) further comprising a transmission ( 10 ) which transmits, in use, the power from said motor ( 6 ) to said drive shaft ( 7 );
said transmission ( 10 ) being a gear reducer and comprising:
an external support casing ( 11 );
an input shaft ( 12 , 12 ′) supported by said external support casing ( 11 ) and connected to said motor ( 6 ); and
an output shaft ( 13 ) supported by said external support casing ( 11 ) and connected to said drive shaft ( 7 );
said external support casing ( 11 ) comprising a support element ( 16 ; 16 ′);
said input shaft ( 12 ; 12 ′) rotating, in use, about a third axis (E, E′);
said transmission ( 10 ) comprising a first coupling assembly ( 14 ) for coupling said input shaft ( 12 ) to said external support casing ( 11 );
said first coupling assembly ( 14 ) comprising a pair of oblique first rolling bearings ( 17 ; 17 ′) mounted so as to couple said input shaft ( 12 ; 12 ′) to said support element ( 16 ; 16 ′) in a rotating manner about said third axis (E, E′);
said first rolling bearings ( 17 ; 17 ′) comprising:
respective first races ( 18 , 19 ; 18 ′, 19 ′) cooperating radially in contact with a first component ( 16 , 12 ; 16 ′, 12 ′) defined by one from said support element ( 16 ; 16 ′) and said input shaft ( 12 ; 12 ′);
respective second races ( 19 , 18 ; 19 ′, 18 ′) cooperating radially in contact with a second component ( 12 , 16 ; 12 ′, 16 ′) defined by the other from said support element ( 16 ; 16 ′) and said input shaft ( 12 ; 12 ′); and
respective pluralities of rolling elements ( 20 ; 20 ′) adapted to roll on said first and said second races ( 18 , 19 ; 18 ′ 19 ′; 19 , 18 ; 19 ′, 18 ′);
characterized by further comprising a pair of preloaded elastic members ( 21 ; 21 ′), which couple said first races ( 18 , 19 ; 18 ′, 19 ′) to said first component ( 16 , 12 ; 16 ′, 12 ′) respectively, axially and in an elastically yielding manner;
wherein said pair of preloaded elastic members ( 21 ; 21 ′) is arranged axially between said first races ( 18 , 19 ; 18 ′, 19 ′);
wherein said first component ( 16 , 12 ; 16 ′, 12 ′) defines a pair of first shoulders ( 33 ; 33 ′) arranged axially between said pair of preloaded elastic members ( 21 ; 21 ′); said pair of preloaded elastic members ( 21 ; 21 ′) coupling said first races ( 18 , 19 ; 18 ′, 19 ′) to said first shoulders ( 33 ; 33 ′) respectively, in an elastically yielding manner in an axial direction;
wherein said first component ( 16 , 12 ; 16 ′, 12 ′) defines a pair of second shoulders ( 35 ; 35 ′) respectively axially facing said first races ( 18 , 19 ; 18 ′, 19 ′), so as to define respective axial end-stops for said first races ( 18 , 19 ; 18 ′, 19 ′);
said output shaft ( 13 ) being coupled to said external support casing ( 11 ) by means of a second coupling assembly ( 110 ), which comprises at least one second rolling bearing ( 111 , 112 );
said first races ( 18 , 19 ; 18 ′, 19 ′) being configured to float, in use, along said third axis (E, E′) in response to the application of an axial load on said first component ( 16 , 12 ; 16 ′, 12 ′);
said transmission ( 30 ) further comprising a third coupling assembly ( 101 ) for rotatably supporting said input shaft ( 12 , 12 ′) with respect to said external support casing ( 11 );
said third coupling assembly ( 101 ) comprising at least one third radial rolling bearing ( 102 , 103 ) configured to transfer whole radial loads from said input shaft ( 12 , 12 ′) to said external support casing ( 11 );
said oblique first rolling bearings ( 17 , 17 ′) being configured to transfer an axial load from said input shaft ( 12 , 12 ′) and said external support casing ( 11 ) and being operated to transfer only said axial load, in use.

2. The aircraft according to claim 1 , wherein said first races ( 18 , 19 ; 18 ′, 19 ′) are made of a first material and said rolling elements ( 20 ; 20 ′) are made of a second material different from said first material and having a coefficient of thermal expansion different from that of said first material.

3. The aircraft according to claim 1 , wherein said first races ( 18 , 19 ; 18 ′, 19 ′) are arranged axially between said pair of preloaded elastic members ( 21 ; 21 ′).

4. The aircraft according to claim 1 , wherein said first component ( 16 , 12 ; 16 ′, 12 ′) defines a shoulder member ( 30 ; 30 ′) comprising a base ( 34 ; 34 ′) and a projection ( 32 ; 32 ′) which protrudes radially towards said second component ( 12 , 16 ; 12 ′, 16 ′), defining a pair of slots ( 31 ; 31 ′) with said base ( 34 ; 34 ′) respectively engaged by said pair of preloaded elastic members ( 21 ; 21 ′); said base ( 34 ; 34 ′) and said projection ( 32 ; 32 ′) defining said pair of second shoulders ( 35 ; 35 ′) and said pair of first shoulders ( 33 ; 33 ′) respectively.

5. The aircraft according to claim 1 , wherein each of said pair of preloaded elastic members ( 21 ; 21 ′) comprises one or more springs ( 50 ; 51 ; 52 ) arranged in series and each spring selected from the group consisting of:
a disk spring ( 50 );
a helical spring ( 51 ); and
a wave spring ( 52 ).

6. The aircraft according to claim 1 , wherein:
said first races ( 18 , 19 ; 18 ′, 19 ′) are defined by respective radially external races ( 18 , 18 ′) of said oblique first rolling bearings ( 17 ); and
said first component ( 16 , 12 ; 16 ′, 12 ′) is defined by said support element ( 16 , 16 ′);

said pair of oblique first rolling bearings ( 17 ) being mounted in a back-to-back configuration.

7. The aircraft according to claim 1 , wherein:
said first races ( 18 , 19 ; 18 ′, 19 ′) are defined by respective radially internal races ( 19 , 19 ′) of said oblique rolling bearings ( 17 ′); and
said first component ( 16 , 12 ; 16 ′, 12 ′) is defined by said input shaft ( 12 ; 12 ′);

said pair of oblique first rolling bearings ( 17 ′) being mounted in a face-to-face configuration.

8. The aircraft according to claim 1 , characterized said third coupling assembly ( 101 ) is axially interposed between said motor ( 6 ) and said first coupling assembly ( 14 ).

9. The aircraft according to claim 1 , characterized in that said transmission ( 10 ) comprises a helix gearing ( 100 ) for rotatably coupling said first input shaft ( 12 ) and said output shaft ( 13 ).

10. The aircraft according to claim 9 , characterized in that said helix gearing ( 100 ) is axially interposed between said third radial rolling bearing ( 102 , 103 ).

11. The aircraft according to claim 9 , characterized in that said second coupling assembly ( 110 ) comprises said second rolling bearing ( 111 ) and a fourth rolling bearing ( 112 );
said gearing ( 100 ) being axially interposed between said second rolling bearing ( 111 ) and said fourth rolling bearing ( 112 );
said fourth rolling bearing ( 112 ) being an oblique rolling bearing configured to tr

Assignees

• Leonardo Spa

Inventors

• Podda Daniele
• Gabrielli Andrea
• Regonini Roberto
• Montagna Federico
• Poggi Stefano

Classifications

• B64D35/00 Primary

  Transmitting power from power plants to propellers or rotors; Arrangements of transmissions · CPC title

• B64C29/0033

  the propellers being tiltable relative to the fuselage · CPC title

• F16C19/18

  with two or more rows of balls · CPC title

• F16C19/543

  in O-arrangement · CPC title

• F16C25/083

  with resilient means acting axially on a race ring to preload the bearing · CPC title