# US 11,905,846 B2 · Turbomachine polyspherical hub for variable pitch blades

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- Number: US 11,905,846 B2
- Document ID: US11905846B2
- Status: Granted
- Kind: B2
- Application number: 17/640,712
- Filed: 2020-09-04
- Published: 2022-10-20
- Granted: 2024-02-20
- Earliest claimed: 2019-09-06
- Assignees: Safran Aircraft Engines
- Applicants: Safran Aircraft Engines
- Inventors: Anthony Binder; Eva Julie Lebeault; Laurent Soulat
- Web page: https://patentgrep.com/patent/US11905846B2

## CPC

- F01D 5/145: {Means for influencing boundary layers or secondary circulations (for compressors F04D29/68)}
- F01D 7/00: Rotors with blades adjustable in operation; Control thereof (for reversing F01D1/30)
- B64C 11/06: for variable-pitch blades
- F04D 29/322: {Blade mountings}
- F04D 29/323: {adjustable}
- F04D 29/324: {Blades}
- B64D 2027/005: {Aircraft with an unducted turbofan comprising contra-rotating rotors, e.g. contra-rotating open rotors [CROR]}
- F05D 2220/36: specially adapted for the fan of turbofan engines
- F05D 2250/241: spherical
- F05D 2250/711: convex
- F05D 2250/712: concave
- F05D 2250/713: inflexed
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- B64C: AEROPLANES; HELICOPTERS
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

The present invention concerns a turbomachine hub, intended to be mounted so as to be able to rotate about a longitudinal axis (X) of the turbomachine, the hub comprising a main body (1) arranged around the longitudinal axis (X), an outer surface of which has a plurality of recesses; a plurality of platforms (3) comprising an outer surface delimited by a circular outer edge of radius r, each platform (3) being arranged in a corresponding recess of the plurality of recesses of the main body (1), and intended to receive a variable pitch blade (2), the pitch of which is variable according to a pitch change axis (Z), the platform (3) being centred and able to rotate about the pitch change axis (Z); characterised in that, for each platform, at least one part of the outer surface of the platform (3) and the main body (1) of the hub comprises a curvature defined by a same sphere portion of radius R and centre C, the at least one part being situated at the outer edge of the platform (3), in a junction zone between the platform (3) and the main body of the hub (1), the centre C of the sphere being situated on the pitch change axis (Z) outside a hemispherical zone delimited between the longitudinal axis (X) and the outer surface of the platform (3).

## Claims

### Claim 1

A turbomachine hub to be mounted in rotation along a longitudinal axis of a turbomachine, the turbomachine hub comprising a main body disposed around the longitudinal axis, of which an outer surface has a plurality of housings;
a plurality of platforms comprising an outer surface delimited by a circular outer edge of radius r, each platform being disposed in a corresponding housing of the plurality of housings of the main body, and intended configured to receive a variable pitch blade according to a pitch change axis, each platform being centered and movable in rotation along the pitch change axis;
wherein, for each platform, at least part of the outer surface of each platform and of the main body of the turbomachine hub comprises a curvature defined by a same spherical portion of radius R and center C, the at least part of the outer surface being situated at the outer edge of each platform, in a junction zone of each platform and of the main body of the turbomachine hub,
the center C being situated on the pitch change axis outside a hemispherical zone delimited between the longitudinal axis and the outer surface of each platform.

### Claim 2 (depends on 1)

The turbomachine hub according to claim 1, wherein the outer surface of the platform is entirely defined by the spherical portion of radius R and center C.

### Claim 3 (depends on 1)

The turbomachine hub according to claim 1, wherein the junction zone is defined by a projection of the junction zone into a plane orthogonal to the pitch change axis, the projection being a ring centered on the pitch change axis and delimited between a circle with inner radius ri less than the radius r of the outer edge of each platform, and a circle with outer radius re greater than the radius r of the outer edge of each platform.

### Claim 4 (depends on 3)

The turbomachine hub according to claim 3, wherein the outer surface of each platform comprises a central part having a curvature opposite to the curvature of the outer surface in the junction zone, a projection of the central part in the plane orthogonal to the pitch change axis being delimited by the circle of inner radius ri.

### Claim 5 (depends on 1)

The turbomachine hub according to claim 1, wherein the center C defining the outer surface of each platform is situated at the intersection of the pitch change axis and of the longitudinal axis.

### Claim 6 (depends on 1)

The turbomachine hub according to claim 1, wherein the main body of the turbomachine hub comprises a plurality of intermediate zones situated between two junction zones with adjacent platforms of the plurality of platforms, each intermediate zone having an outer surface having a curvature opposite to the curvature of the outer surface of the main body in the junction zone.

### Claim 7 (depends on 1)

A turbomachine assembly comprising a turbomachine hub according to claim 1 and a plurality of variable pitch blades configured to be connected to the main body of the turbomachine hub by means of the plurality of platforms.

### Claim 8 (depends on 7)

The assembly according to claim 7, wherein each platform of the plurality of platforms is made in one piece with a corresponding blade of the plurality of blades.

### Claim 9 (depends on 7)

The assembly according to claim 7, wherein each platform comprises at least two distinct parts, intended to surround a root part of a corresponding blade.

### Claim 10 (depends on 7)

The assembly according to claim 7, wherein the outer surface of each platform is complementary to the shape of a corresponding blade, so that the platform is in contact with the corresponding blade from a leading edge of the corresponding blade to a trailing edge of the corresponding blade, and is also in contact with a suction side and a pressure side of the corresponding blade.

### Claim 11 (depends on 7)

A turbomachine with a shrouded or unshrouded fan, comprising an assembly according to claim 7.