SOLAR POWER FOR A MECHANICAL REDUCTION GEARBOX ON AN AIRCRAFT TURBOMACHINE

Abstract

A solar element (50) for a mechanical gearbox (6) of an aircraft turbomachine (1), this solar element (50) having an annular shape around an axis (X) and comprising: - an inner annular portion (52) having coupling splines (53) on its inner periphery, - an outer annular portion (54) having at least one meshing tooth (56) on its outer periphery, this outer portion (54) extending around the inner portion (52), and - an annular web (58) connecting the inner and outer portions (52, 54), at least one of the inner and outer portions (52, 54) comprising two independent rings (60, 62), each having splines (53) or teeth (56), and the web (58) comprising two annular branches (64, 66) connected respectively to these two rings (60, 62). Figure for the abbreviation: Figure 6

Description

Title of the invention: SOLAR FOR A MECHANICAL REDUCER OF AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to the field of mechanical reducers for turbomachines, particularly aircraft. Technical background

[0002] The state of the art includes in particular documents WO-A1-2010 / 092263, FR-A1-2 987 416, FR-A1-3 008 462, FR-A1-3 008 462 and FR-A1-3 041 054.

[0003] The role of a mechanical reducer is to modify the speed and torque ratio between the input axis and the output axis of a mechanical system.

[0004] New generations of dual-flow turbomachines, particularly those with a high bypass ratio, include a mechanical reducer to drive the shaft of a fan (also called a "fan"). Usually, the reducer aims to transform the so-called fast rotation speed of the shaft of a power turbine into a slower rotation speed for the shaft driving the fan.

[0005] Such a reducer comprises a central pinion, called a sun gear, a crown gear and pinions called satellites, which are engaged between the sun gear and the crown gear. The satellites are held by a frame called a planet carrier. The sun gear, the crown gear and the planet carrier are planetary gears because their axes of revolution coincide with the longitudinal axis X of the turbomachine. The satellites each have a different axis of revolution and are equally distributed over the same operating diameter around the axis of the planetary gears. These axes are parallel to the longitudinal axis X.

[0006] There are several gearbox architectures. In the state of the art of dual-flow turbomachines, the gearboxes are of the planetary or epicyclic type. In other similar applications, there are so-called differential or "compound" architectures.

[0007] - On a planetary reducer, the planet carrier is fixed and the crown constitutes the output shaft of the device which rotates in the opposite direction of the solar.

[0008] - On an epicyclic reducer, the crown is fixed and the planet carrier constitutes the output shaft of the device which rotates in the same direction as the solar.

[0009] - On a differential reducer, no element is fixed in rotation. The crown rotates in the opposite direction of the solar and the satellite carrier.

[0010] The reducers can be composed of one or more meshing stages. This meshing is ensured in different ways such as by contact, by friction or even by magnetic fields.

[0011] There are several types of contact meshing such as with straight, helical or herringbone teeth.

[0012] One of the problems with a reducer of this type concerns the absorption of external forces and manufacturing defects which must be compensated for by flexibility on the interfaces.

[0013] In the present application, the term "flexibility" means an ability of a part or part of a part to deform elastically in order to be able to absorb forces, in particular during the transmission of a rotational torque.

[0014] The term “interface” means a connection between two parts, this connection being able to be for example a mesh (via one or more teeth for example) or a coupling (via splines).

[0015] In the current technique, it is known to provide flexibility at the input shaft of the reducer or at the interface between the input shaft and the solar.

[0016] The input shaft comprises a tubular end which is engaged in the sun and which comprises coupling splines with complementary splines of the sun. This shaft may comprise a flexibility which is generally in the form of a bellows giving the shaft an elastic deformation capacity in bending or in torsion.

[0017] Alternatively, an intermediate connecting piece between the input shaft and the solar can include flexibility.

[0018] These technologies are however not entirely satisfactory because they generally result in an imbalance in the transmission of forces to the solar and therefore in an inhomogeneous loading of the teeth of the solar. A homogeneous distribution of the loads on the teeth of the solar is on the contrary desired to limit the constraints to which the solar is subjected in operation.

[0019] The invention provides a solution to this problem, which is simple, effective and economical. Summary of the invention

[0020] The invention relates to a solar for a mechanical reducer (6) of an aircraft turbomachine, this solar having an annular shape around an axis and comprising:

[0021] - an internal annular part comprising grooves at its internal periphery coupling,

[0022] - an external annular part comprising at its external periphery at least one meshing teeth, this external part extending around the internal part, and

[0023] - an annular web connecting the internal and external parts, this web being located between the internal and external parts and having a shape giving the solar a capacity for deformation, in particular in bending,

[0024] characterized in that:

[0025] - at least one of the inner and outer parts comprises two independent rings each comprising grooves or teeth, and

[0026] - the veil comprises two annular branches connected respectively to these two rings.

[0027] The invention thus proposes to provide flexibility directly in the solar. This flexibility is provided by the web connecting the internal and external parts of the solar. Advantageously, the web provides flexibility in the radial and axial directions to the solar, that is to say that the rings are able to move radially relative to each other and therefore to be offset. This movement is made possible by an elastic deformation of the web which thus absorbs forces during the transmission of a rotational torque.

[0028] The solution proposed below is compatible: • a single or multi-stage reducer, • a planetary, epicyclic or differential reducer, • straight, helical or herringbone teeth, • any type of planet carrier, whether monobloc or cage and carrier type cage, • any type of satellite bearing, whether it is composed of a rolling element, a hydrodynamic bearing, etc.

[0029] The solar according to the invention may comprise one or more of the following characteristics, taken in isolation from one another, or in combination with one another: the internal part comprises two internal rings having grooves on their internal periphery, the veil comprising two branches connected respectively to the internal rings; the external part comprises two external rings each comprising a tooth on their external periphery, the veil comprising two branches connected respectively to the external rings; the two branches extend from the inner part to the outer part; the two branches are parallel to each other and perpendicular to the axis; the two branches which are connected to the inner rings are connected by a single partition to the outer part, or the two branches which are connected to the outer rings are connected by a single partition to the inner part; the single partition is perpendicular to the axis and connected to the middle of the external or internal part; the two branches are truncated, and form a V shape in axial section; - the veil has a general Y shape in axial section; - the two internal branches are connected to the two external branches approximately in the middle of the veil, that is to say halfway between the internal and external parts;

[0030] — the two internal branches are connected to the two external branches by a wire annular wall of the veil or by a cylindrical wall of the veil;

[0031] - the two branches of the veil are connected to each other by a cylindrical wall of the veil ; - the veil has a general X or H shape in axial section; - the veil is made in one piece;

[0032] — the solar is made in one piece;

[0033] — the veil is formed from a single piece with at least a part of each of the internal and external parts;

[0034] — the rings of the internal part are axially spaced from each other, and / or the rings of the outer part are axially spaced from each other;

[0035] — the axial distance between the rings of the internal part is greater than or equal to the axial dimension of each of the rings of the internal part;

[0036] — the axial distance between the rings of the external part is less than or equal to the axial dimension of each of the rings of the external part;

[0037] — the axial distance between the rings of the inner part is different from the distance axial between the rings of the outer part; in particular, the axial distance between the rings of the inner part is greater than the axial distance between the rings of the outer part;

[0038] — the rings of the internal part are independent so as to be able to move independently of each other, and / or the rings of the outer part are independent so that they can move independently of each other.

[0039] The present invention also relates to a mechanical reducer for an aircraft turbomachine, this reducer comprising:

[0040] - a planet carrier which comprises a first axis of rotation,

[0041] - a solar as described above which is mounted in the planet carrier and which is centered on the first axis,

[0042] - a crown which extends around the solar and the first axis, and

[0043] - satellites which are carried by the satellite carrier and which are meshed with the solar and corona, the satellites having second axes of rotation parallel to the first axis.

[0044] The invention further relates to a turbomachine, in particular for an aircraft, comprising a mechanical or solar reducer as described above. Brief description of the figures

[0045] Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[0046] [Fig-1] [Fig.l] is a schematic axial sectional view of a turbomachine using the invention,

[0047] [Fig.2] [Fig.2] is a partial axial sectional view of a mechanical reducer,

[0048] [Fig.3] [Fig.3] is a very schematic partial axial sectional view of a solar for an aircraft mechanical reducer,

[0049] [Fig.4] [Fig.4] is a schematic perspective view of a solar for a aircraft mechanical reducer,

[0050] [Fig.5] [Fig.5] is a schematic axial sectional view of a mechanical reducer aircraft comprising the solar of [Fig.4];

[0051] [Fig.6] [Fig.6] is a partial schematic view in axial section of a solar according to an embodiment of the invention,

[0052] [Fig.7] [Fig.7] is a partial schematic view in axial section of a solar according to an alternative embodiment of the invention,

[0053] [Fig.8] [Fig.8] is a partial schematic view in axial section of a solar according to another variant embodiment of the invention,

[0054] [Fig.9] [Fig.9] is a partial schematic view in axial section of a solar according to another variant embodiment of the invention,

[0055] [Fig. 10] [Fig. 10] is a partial schematic view in axial section of a solar according to another variant embodiment of the invention,

[0056] [Fig. 11] [Fig. 11] is a partial schematic view in axial section of a solar device according to another alternative embodiment of the invention, and

[0057] [Fig. 12] [Fig. 12] is a partial schematic view in axial section of a solar device according to another alternative embodiment of the invention. Detailed description of the invention

[0058] [Fig.l] describes a turbomachine 1 which comprises, in a conventional manner, a fan S, a low-pressure compressor 1a, a high-pressure compressor 1b, an annular combustion chamber 1c, a high-pressure turbine 1d, a low-pressure turbine 1c and an exhaust nozzle 1h. The high-pressure compressor 1b and the high-pressure turbine 1d are connected by a high-pressure shaft 2 and form with it a high-pressure (HP) body. The low-pressure compressor 1a and the low-pressure turbine 1c are connected by a low-pressure shaft 3 and form with it a low-pressure (LP) body.

[0059] The blower S is driven by a fan shaft 4 which is driven by the shaft BP 3 by means of a reducer 6. This reducer 6 is generally of the planetary or epicyclic type.

[0060] The following description concerns an epicyclic type reducer, the planet carrier and the sun gear of which are rotatable, the crown of the reducer being fixed in the motor reference frame.

[0061] The reducer 6 is positioned in the upstream part of the turbomachine. A fixed structure comprising schematically, here, an upstream part 5a and a downstream part 5b which composes the motor casing or stator 5 is arranged so as to form an enclosure E surrounding the reducer 6. This enclosure E is here closed upstream by seals at the level of a bearing allowing the fan shaft 4 to pass through, and downstream by seals at the level of the passage of the LP shaft 3.

[0062] [Fig.2] shows an epicyclic reducer 6. At the input, the reducer 6 is connected to the LP shaft 3, for example via internal splines 7a. Thus, the LP shaft 3 drives a planetary pinion called the sun gear 7. Conventionally, the sun gear 7, whose axis of rotation coincides with that of the turbomachine X, drives a series of pinions called satellites 8, which are equally distributed over the same diameter around the axis of rotation X. This diameter is equal to twice the operating center distance between the sun gear 7 and the satellites 8. The number of satellites 8 is generally defined between three and seven for this type of application.

[0063] Alternatively, the satellites 8 could not be equally distributed around the X axis.

[0064] All of the satellites 8 are held by a chassis called a satellite carrier 10. Each satellite 8 rotates around its own Y axis, and meshes with the crown 9.

[0065] At the output we have: • In this epicyclic configuration, the set of satellites 8 drives the planet carrier 10 in rotation around the axis X of the turbomachine. The crown is fixed to the engine casing or stator 5 via a crown carrier 12 and the planet carrier 10 is fixed to the fan shaft 4. • In another planetary configuration, all of the planet gears 8 are held by a planet gear carrier 10 which is fixed to the engine casing or stator 5. Each planet gear 8 drives the crown wheel which is attached to the fan shaft 4 via a crown wheel carrier 12. • In another differential configuration, all of the satellites 8 are held by a planet carrier 10 which is connected to a first fan shaft 5. Each satellite 8 drives the crown which is connected to a second counter-rotating fan shaft 4 via a crown carrier 12.

[0066] Each satellite 8 is mounted to rotate freely using a bearing 11, for example of the rolling bearing or hydrodynamic bearing type. Each bearing 11 is mounted on one of the axes 10b of the planet carrier 10 and all the axes are positioned relative to each other. others using one or more structural frames 10a of the planet carrier 10. There are a number of axes 10b and bearings 11 equal to the number of satellites. For reasons of operation, assembly, manufacturing, control, repair or replacement, the axes 10b and the frame 10a can be separated into several parts.

[0067] For the same reasons cited above, the teeth of a satellite can be separated into several helices or teeth each having a median plane P, P'. In our example, we detail the operation of a reducer in which each satellite comprises two series of chevron teeth cooperating with a crown separated into two half-crowns: • An upstream half-crown 9a consisting of a rim 9aa and a half-fixing flange 9ab. On the rim 9aa is the front propeller meshing with a propeller of the toothing 8d of each satellite 8. The propeller of the toothing 8d also meshes with that of the sun 7. • A downstream half-crown 9b consisting of a rim 9ba and a half-fixing flange 9bb. On the rim 9ba is the rear propeller meshing with a propeller of the toothing 8d of each satellite 8. The propeller of the toothing 8d also meshes with that of the sun 7.

[0068] If the helix widths vary between the sun gear 7, the satellites 8 and the crown 9 because of the tooth overlaps, they are all centered on a median plane P for the upstream teeth and on another median plane P' for the downstream teeth.

[0069] [Fig.2] thus illustrates the case of a single-stage gear reducer 6, i.e. the same toothing 8d of each satellite 8 cooperates with both the sun gear 7 and the crown wheel 9. Even if the toothing 8d comprises two series of teeth, these teeth have the same average diameter and form a single toothing called a chevron.

[0070] The fixing half-flange 9ab of the upstream crown 9a and the fixing half-flange 9bb of the downstream crown 9b form the fixing flange 9c of the crown. The crown 9 is fixed to a crown carrier by assembling the fixing flange 9c of the crown and the fixing flange 12a of the crown carrier using a bolted assembly for example.

[0071] The arrows in [Fig.2] describe the routing of the oil in the reducer 6. The oil arrives in the reducer 6 from the stator part 5 in a distributor 13 by different means which will not be specified in this view because they are specific to one or more types of architecture. The distributor 13 comprises injectors 13a and arms 13b.

[0072] The injectors 13a have the function of lubricating the teeth and the arms 13b have the function of lubricating the bearings. The oil is brought to the injector 13a to exit through the end 13c in order to lubricate the teeth. The oil is also brought to the arm 13b and circulates via the supply port 13d of the bearing. The oil then circulates through the shaft in one or more buffer zones 10c and then exits through the ports 10d in order to lubricate the bearings of the satellites.

[0073] In the prior art shown in [Fig.2], a reduction gear 7 comprises an annular body extending around the axis X and comprising at its internal periphery the splines 7a for coupling with the shaft 3, and at its external periphery a toothing 7b for meshing with the toothing 8d of each satellite 8. The splines 7a are located in a central bore A passing through the body which is centered on the axis X.

[0074] [Fig.3] to 5 schematically illustrate a solar system comprising an elastic deformation capacity during operation.

[0075] The solar 20 comprises an annular body 22 extending around the axis X and comprising at its internal periphery the splines 24 for coupling with the shaft 3, and at its external periphery a toothing 26 for meshing with the toothing 8d of each satellite 8.

[0076] The body 22 has the particularity of comprising two rings, respectively external 28 and internal 30, which are coaxial and extend around each other.

[0077] The outer ring 28 has at its outer periphery the aforementioned toothing 26. This toothing 26 may comprise two series of adjacent teeth separated axially from each other by an annular groove 27 opening radially outwards. These two series of teeth have the same diameter and may be chevron-shaped.

[0078] The external ring 28 has at its internal periphery an internal surface 32, for example cylindrical.

[0079] The internal ring 30 comprises at its internal periphery the aforementioned grooves 24. These grooves 24 are for example straight or rectilinear and parallel to the axis X.

[0080] The internal ring 30 has at its external periphery an external surface 34, for example cylindrical.

[0081] The body 22 further comprises an annular connecting web 36 which is located between the rings 28, 30 and more particularly between the surfaces 32, 34.

[0082] Figures 6 to 12 illustrate several embodiments of the invention.

[0083] The solar 50 according to the invention has an annular shape around an axis X and comprises:

[0084] - an internal annular part 52 comprising grooves at its internal periphery coupling 53,

[0085] - an external annular part 54 comprising at its external periphery at least one meshing teeth 56, this external part 54 extending around the internal part 52, and

[0086] - an annular web 58 connecting the internal and external parts 52, 54, this web 58 being located between the inner and outer parts 52, 54 and having a shape giving the solar 50 an elastic deformation capacity.

[0087] The splines 53 are configured to be coupled to complementary splines of an input shaft of the reducer, as described above.

[0088] The teeth 56 are configured to be meshed with complementary teeth of satellites of the reducer, as described above.

[0089] According to the invention:

[0090] - at least one of the inner and outer parts 52, 54 comprises two independent rings pendants each comprising grooves 53 or teeth 56, and

[0091] - the veil 58 comprises two annular branches connected respectively to these two rings.

[0092] In the embodiment of [Fig.6], it is the internal part 52 of the ring 50 which comprises two internal rings 60, 62. These rings 60, 62 comprise grooves 53 at their internal periphery. The web 58 comprises two internal branches 64, 66 connected respectively to the internal rings 60, 62.

[0093] At their external periphery, the two branches 64, 66 are connected by a single partition 68 to the external part 54. This single partition 68 is perpendicular to the X axis and connected to the middle of the external part 54.

[0094] In the example shown, the two branches 64, 66 are frustoconical, and form in axial section a V shape whose opening is oriented radially inwards, that is to say towards the X axis. The web 58 has in axial section a general Y shape, which is here inverted.

[0095] The axial distance L1 between the rings 60, 62 is greater than the axial dimension DI of each of these rings.

[0096] In the embodiment of [Fig.7], each of the inner and outer parts 52, 54 of the ring 50 comprises two rings, respectively inner 60, 62 and outer 70, 72. The rings 60, 62 of the inner part 52 have grooves 53 at their inner periphery. The rings 70, 72 of the outer part 54 each have a toothing 56 at their outer periphery. The web 58 has two inner branches 64, 66 connected respectively to the inner rings 60, 62, and two outer branches 74, 76 connected respectively to the outer rings 70, 72.

[0097] The two internal branches 64, 66 are connected to the two external branches 74, 76 substantially in the middle of the web 58, that is to say halfway between the internal and external parts 52, 54.

[0098] In the example shown, the two internal branches 64, 66 are connected to the two external branches 74, 76 by an annular wire 78 of the web 58, that is to say by an annular part of the web having small dimensions in the axial and radial direction.

[0099] Still in the example shown, each of the branches 64, 66, 74, 76 has a generally truncated cone shape. The web 58 has a generally X-shaped axial section, or the branches 64, 66, 74, 76 form an X shape in axial section.

[0100] The axial distance L1 between the rings 60, 62 is greater than the axial dimension DI of each of these rings. The axial distance L2 between the rings 70, 72 is less than the axial dimension D2 of each of these rings. In the example shown, L1 is greater than L2

[0101] In the embodiment of [Fig.8], it is the external part 54 of the ring 50 which comprises two external rings 70, 72. These rings 70, 72 each comprise a toothing 56 at their internal periphery. The web 58 comprises two external branches 74, 76 connected respectively to the external rings 70, 72.

[0102] At their internal periphery, the two branches 74, 76 are connected by a single partition 78 to the internal part 52. This single partition 78 is perpendicular to the X axis and connected to the middle of the internal part 52.

[0103] In the example shown, the two branches 74, 76 are frustoconical, and form a V shape in axial section. The web 58 has a general Y shape in axial section.

[0104] The axial distance L2 between the rings 70, 72 is less than the axial dimension D2 of each of these rings.

[0105] In the embodiment of [Fig.9], each of the inner and outer parts 52, 54 of the ring 50 comprises two rings, respectively inner 60, 62 and outer 70, 72. The rings 60, 62 of the inner part 52 have grooves 53 at their inner periphery. The rings 70, 72 of the outer part 54 each have a toothing 56 at their outer periphery. The web 58 has two inner branches 64, 66 connected respectively to the inner rings 60, 62, and two outer branches 74, 76 connected respectively to the outer rings 70, 72.

[0106] The two internal branches 64, 66 are connected to the two external branches 74, 76 substantially in the middle of the web 58, that is to say halfway between the internal and external parts 52, 54.

[0107] In the example shown, the two internal branches 64, 66 are connected to the two external branches 74, 76 by a cylindrical wall 80 of the web 58 which is centered on the axis X.

[0108] The free annular edges 80a, 80b of this wall 80 are connected respectively to the external peripheries of the internal branches 64, 66. The branches 74, 76 extend from the external cylindrical surface 80c of the wall 80 to the external rings 70, 72.

[0109] Still in the example shown, each of the branches 64, 66, 74, 76 has a radial orientation and is therefore perpendicular to the X axis. The web 58 has a general H shape in axial section.

[0110] The axial distance L1 between the rings 60, 62 is greater than the axial dimension DI of each of these rings. The axial distance L2 between the rings 70, 72 is less than the axial dimension D2 of each of these rings. In the example shown, L1 is greater than L2

[0111] In the embodiment of [Fig. 10], it is the external part 54 of the ring 50 which comprises two external rings 70, 72. These rings 70, 72 have teeth 56 at their external periphery. The web 58 has two branches 84, 86 connected respectively to the external rings 70, 72.

[0112] The veil 58 is formed by these two branches 84, 86 which extend from the external part 54 to the internal part 52.

[0113] At their internal periphery, the two branches 84, 86 are connected to an external cylindrical surface of the internal part 52.

[0114] The axial distance L2 between the rings 70, 72 is less than the axial dimension D2 of each of these rings.

[0115] In the embodiment of [Fig. 11], each of the inner and outer parts 52, 54 of the ring 50 comprises two rings, respectively inner 60, 62 and outer 70, 72. The rings 60, 62 of the inner part have grooves 53 at their inner periphery. The rings 70, 72 of the outer part each have a toothing 56 at their outer periphery. The web 58 has two inner branches 64, 66 connected respectively to the inner rings 60, 62, and two outer branches 74, 76 connected respectively to the outer rings 70, 72.

[0116] The two internal branches 64, 66 are connected to the two external branches 74, 76 substantially in the middle of the web 58, that is to say halfway between the internal and external parts 52, 54.

[0117] In the example shown, the two internal branches 64, 66 are connected to the two external branches 74, 76 by a cylindrical wall 80 of the web 58.

[0118] Still in the example shown, each of the branches 74, 76 has a generally truncated cone shape and each of the branches 64, 66 is perpendicular to the X axis.

[0119] The free annular edges 80a, 80b of the wall 80 are connected respectively to the external peripheries of the internal branches 64, 66. The branches 74, 76 extend from the middle of the external cylindrical surface 80c of the wall 80 to the external rings 70, 72.

[0120] The veil 58 has a general H shape in axial section.

[0121] The axial distance L1 between the rings 60, 62 is greater than the axial dimension DI of each of these rings. The axial distance L2 between the rings 70, 72 is less than the axial dimension D2 of each of these rings. In the example shown, L1 is greater than L2

[0122] In the embodiment of [Fig. 12], each of the inner and outer parts 52, 54 of the ring 50 comprises two rings, respectively inner 60, 62 and outer 70, 72. The rings 60, 62 of the inner part 52 have grooves 53 at their inner periphery. The rings 70, 72 of the outer part each have a toothing 56 at their outer periphery. The web 58 has two inner branches 64, 66 connected respectively to the inner rings 60, 62, and two outer branches 74, 76 connected respectively to the outer rings 70, 72.

[0123] The two internal branches 64, 66 are connected to the two external branches 74, 76 substantially in the middle of the web 58, that is to say halfway between the internal and external parts 52, 54.

[0124] In the example shown, the two internal branches 64, 66 are connected to the two external branches 74, 76 by a cylindrical wall 80 of the web 58.

[0125] The free annular edges 80a, 80b of this wall 80 are connected respectively to the external peripheries of the internal branches 64, 66. The free annular edges 80a, 80b are also connected respectively to the internal peripheries of the external branches 74, 76.

[0126] Still in the example shown, each of the branches 64, 66, 74, 76 has a radial orientation and is therefore perpendicular to the X axis. The web 58 has a general H shape in axial section.

[0127] The axial distance L1 between the rings 60, 62 is greater than or equal to the axial dimension DI of each of these rings. The axial distance L2 between the rings 70, 72 is less than the axial dimension D2 of each of these rings. In the example shown, L1 is greater than L2

[0128] Whatever its embodiment, the veil 58, or preferably the solar 50, can be formed from a single piece, for example by additive manufacturing, by machining or by casting.

[0129] The thicknesses of the web 58 and its branches are chosen according to the desired flexibility and the torque to be transmitted.

[0130] The teeth 56 can be straight or herringbone for example.

[0131] The splines 53 can be curved, centered, and could even be hooped or held with a nut. Sufficient flexibility makes it easier to dimension the teeth while keeping the splines added for example.

[0132] The present invention provides several advantages, including:

[0133] - it takes advantage of available space so as not to clutter up the rest of the engine,

[0134] - it allows you to take advantage of added grooves while maintaining axial freedom.

Claims

Claims

1. Sun (50) for a mechanical reducer (6) of an aircraft turbomachine (1), this sun (50) having an annular shape around an axis (X) and comprising: - an internal annular part (52) comprising at its internal periphery coupling splines (53), - an external annular part (54) comprising at its external periphery at least one meshing toothing (56), this external part (54) extending around the internal part (52), and - an annular web (58) connecting the internal and external parts (52, 54), this web (58) being located between the internal and external parts (52, 54) and having a shape giving the sun (50) a capacity for elastic deformation, characterized in that: - at least one of the internal and external parts (52, 54) comprises two independent rings (60, 62, 70, 72) each comprising grooves (53) or teeth (56), and - the web (58) comprises two annular branches (64, 66, 74, 76, 84,86) connected respectively to these two rings (60, 62, 70, 72).,

2. Solar (50) according to claim 1, in which the internal part (52) comprises two internal rings (60, 62) having grooves (53) at their internal periphery, the veil (58) comprising two branches (64, 66) connected respectively to the internal rings (60, 62).

3. Solar (50) according to claim 1 or 2, in which the external part (54) comprises two external rings (70, 72) each comprising a toothing (56) at their external periphery, the veil (58) comprising two branches (74, 76, 84, 86) connected respectively to the external rings (70, 72).

4. Solar (50) according to claim 2 or 3, wherein the two branches (84, 86) extend from the inner part (52) to the outer part (54).

5. Solar (50) according to claim 4, in which the two branches (84, 86) are parallel to each other and perpendicular to the axis (X).

6. A solar (50) according to claim 2 or 3, wherein the two branches (60, 62) which are connected to the inner rings (64, 66) are connected by a single partition (78) to the outer part (54), or the two branches (70, 72) which are connected to the outer rings (74, 76) are connected by a single partition (78) to the internal part (52).

7. Solar (50) according to claim 6, wherein the single partition (78) is perpendicular to the axis (X) and connected to the middle of the external (54) or internal (52) part.

8. Solar (50) according to claim 6 or 7, in which the two branches (60, 62, 70, 72) are frustoconical, and form a V shape in axial section.

9. Solar (50) according to one of claims 6 to 8, in which the veil (58) has a general Y shape in axial section.

10. Solar (50) according to all of claims 2 and 3, in which the two internal branches (60, 62) are connected to the two external branches (70, 72) substantially in the middle of the veil (58), that is to say halfway between the internal and external parts (52, 54).

11. Solar (50) according to claim 10, in which the two branches of the veil (58) are connected to each other by a cylindrical wall (82) of the veil (58).

12. Solar (50) according to claim 10 or 11, in which the veil (58) has a general X or H shape in axial section.

13. Solar (50) according to one of the preceding claims, in which the veil (58) is made in a single piece.

14. Mechanical reducer (6) for an aircraft turbomachine (1), this reducer comprising: - a planet carrier (10) which comprises a first axis of rotation (X), - a sun gear (50) according to one of the preceding claims which is mounted in the planet carrier (10) and which is centered on the first axis (X), - a ring gear (9) which extends around the sun gear (50) and the first axis (X), and - satellites (8) which are carried by the planet carrier (10) and which are meshed with the sun gear (50) and the ring gear (9), the satellites (8) comprising second axes of rotation (Y) parallel to the first axis (X).

15. Aircraft turbomachine (1), comprising a mechanical reducer (6) according to claim 14 or a solar (50) according to one of claims 1 to 13.

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