AIRCRAFT TURBOMACHINE MECHANICAL GEARBOX SATELLITE BRACKET

Abstract

A planet carrier (213) for a mechanical gearbox (10, 110) of an aircraft turbomachine (1), comprising: - a first disk (236) centered on a first axis (X) and extending perpendicularly to this first axis (X), this first disk (236) having first orifices (292) centered respectively on second axes (Y) parallel to this first axis (X), - a second disk (238) centered on the first axis (X) and extending parallel to and at a distance from the first disk (236), this second disk (238) having second orifices (294) which are respectively centered on the second axes (Y), the number of second orifices (294) being equal to the number of first orifices (292), - bridges (296) which extend between the first and second disks (236, 238) and connect them together, the bridges (296) being formed in one piece with the first and second disks (236, 238). Figure for the abbreviation: Figure 6

Description

Title of the invention: SATELLITE CARRIER FOR MECHANICAL REDUCTION GEARBOX OF AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to a satellite carrier and a mechanical gearbox for an aircraft turbomachine, as well as a turbomachine comprising such a satellite carrier or such a gearbox. Technical Downstream Plan

[0002] The state of the art includes in particular documents FR-A1-2 987 416, FR-A1-2 853 382, ​​FR-A1-3 041 054, FR-A1-3 073 915, FR-A1-3 084 428.

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

[0004] New generations of turbofan engines, particularly those with a high bypass ratio, include a mechanical gearbox to drive the shaft of a fan. Typically, the purpose of the gearbox is to transform the high rotational speed of the power turbine shaft into a slower rotational speed for the fan-driving shaft.

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

[0006] Several gearbox architectures exist. In the state of the art of turbofan engines, 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 s is fixed and the ring constitutes the output shaft of the device which rotates in the opposite direction to the solar.

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

[0009] - on a differential reducer, no element is fixed for rotation. The ring rotates in the opposite direction to the solar panel and the satellite carrier.

[0010] Reducers can be composed of one or more meshing stages. This meshing is achieved in various ways such as by contact, by friction, or by magnetic field. There are several types of contact meshing such as with straight or herringbone teeth.

[0011] The satellite carrier may be a single unit or consist of a cage and a cage carrier. The cage comprises an internal cavity housing the solar array, the satellites, and the guidance bearings for these satellites. The solar array has internal splines for coupling to a first shaft of the turbomachine, and the cage carrier comprises a cylindrical portion with external splines for coupling to another shaft.

[0012] The connection between the cage and the cage holder is generally rigid. Alternatively, a technology can be considered in which the cage is connected to the cage holder by "flexible" connections, as described in document FR-A1-2 853 382. In such a case, the cage holder comprises an annular row of axial fingers that carry first connecting elements. These first connecting elements cooperate with second connecting elements mounted in housings in the cage to form the flexible connections between the cage holder and the cage, which allow at least one degree of freedom.

[0013] During operation, the planet carrier is subjected to forces that tend to deform it. This is the case for a one-piece planet carrier or a cage-and-cage type carrier. These deformations cause the planets to tilt, leading to a degradation of the meshing and the risk of an asymmetrical oil film forming when using plain or hydrodynamic planetary guidance bearings, or the risk of roller tilting when using roller bearings for planetary guidance. These forces and deformations must be rebalanced to limit or even eliminate these effects.

[0014] Furthermore, the satellite carrier contains bores to accommodate the ends of the satellite guide bearings. These bores can be machined, and machining tolerances can generate dimensional and positional defects in these bores. To reduce the positional tolerances of these bores, they can be ground, which is restrictive from an industrial standpoint. It is also possible to choose the material of the satellite carrier to reduce its stiffness, for example, using titanium or aluminum instead of steel. However, this also generates additional constraints (machinability, mechanical strength, tribological behavior, etc.).

[0015] Misalignments of the satellite bearings, whether plain or roller bearings, and therefore of the satellites themselves, generate an internal overload in the gearbox on at least one of the satellites. This may necessitate oversizing the gearbox components (gears and plain and roller bearings) and thus negatively impact the gearbox's mass and performance.

[0016] The present invention offers a solution to this need, which is simple, effective and economical. Summary of the invention

[0017] The invention relates to a satellite carrier for a mechanical gearbox of an aircraft turbomachine, this satellite carrier comprising:

[0018] - a first disk centered on a first axis or central axis and extending perpendicular to this first axis, this first disk has first orifices or bearing orifices centered respectively on second axes or bearing axes which are distributed around the first axis and parallel to this first axis,

[0019] - a second disk centered on the first axis and extending parallel and at a distance of the first disk, this second disk having second orifices or bearing orifices which are respectively centered on the second axes, the number of second bearing orifices being equal to the number of first bearing orifices,

[0020] - bridges that extend between the first and second discs and connect them between them.

[0021] The principle of the invention is to locally loosen the satellite carrier, particularly in the vicinity of the satellite shaft mounting holes. The internal overload is due to the positional tolerances of the satellite shaft holes. A satellite that is offset from its perfect nominal position can experience a positive or negative load difference depending on the direction of the offset, which can be up to 10% or even more. This effect is amplified by the local stiffness of the satellite carrier between two successive satellites. Thus, the lower this stiffness, the lower this overload. Reducing the design load results in a significant mass saving.

[0022] According to a first aspect of the invention, at least one of the discs comprises an alternation of concave and convex curved portions on each of the inner and outer peripheral edges of the disc, the convex curved portions of the inner peripheral edge and the concave curved portions of the outer peripheral edge being aligned radially with respect to the central axis and extending respectively radially inside and radially outside the bearing holes of the disc, and the concave curved portions of the inner peripheral edge and the convex curved portions of the outer peripheral edge being aligned radially with respect to the central axis and the number of concave and convex curved portions of the inner and outer peripheral edges of the disc being equal to the number of bearing holes of this disc.

[0023] The planet carrier according to the invention is thus configured to improve its operating behavior and, in particular, its resistance to deformations caused by the transmission of forces. The impact on the bearings, such as their misalignment or asymmetry, is thus reduced.

[0024] This is made possible by the specific shapes of the inner and outer peripheral edges of the disk or disks. Each of these edges comprises alternating concave and convex curved portions. The number of concave curved portions on the inner peripheral edge is equal to the number of convex curved portions on that edge, and is also equal to the number of openings in that disk. The number of concave curved portions on the outer peripheral edge is equal to the number of convex curved portions on that edge, and is also equal to the number of openings in that disk.

[0025] The concave curved portions of the inner peripheral edge and the convex curved portions of the outer peripheral edge are radially aligned and located between the orifices of the disc. The convex curved portions of the inner peripheral edge and the concave curved portions of the inner peripheral edge are radially aligned and located radially on either side of the orifices of the disc.

[0026] This first aspect allows for a reduction in the thickness or material ligaments at the interface between the planet carrier and the bearing axes in the radial planes. Each ligament can be reduced to the minimum necessary to hold the corresponding bearing's receiving hole.

[0027] According to a second aspect of the invention, the bearing holes of at least one of the disks are distributed in pairs, each pair of bearing holes comprising two circumferentially adjacent bearing holes, the disk or each disk comprising pairs of bearing holes comprising, between each pair of bearing holes, a first through hole which is cut by a first plane extending radially with respect to the central axis and located at equal distances from the bearing holes of the pair, and which is cut by a second plane passing through the bearing axes of this pair of bearing holes, the first plane being a first plane of symmetry for the hole.

[0028] The planet carrier according to the invention is thus configured to improve its operating behavior and, in particular, its resistance to deformations caused by the transmission of forces. The impact on the bearings, such as their misalignment or asymmetry, is thus reduced.

[0029] The first hole serves only a weight-relieving function and has no additional or other function, such as a fixing hole. Each first hole is therefore preferably smooth, i.e., not tapped.

[0030] The second aspect of the invention makes it possible to make the areas between the orifices more flexible, at mid-distance from these orifices. A zone of flexibility is thus added in the tangential plane, equidistant from the two orifices. The optimum zone is located at the intersection of the plane passing through the two centers of the orifices and the plane of symmetry of the two orifices. The presence of the holes at a distance from the orifices also makes it possible to avoid excessive local deformations can generate fretting between bearings and planet carriers.

[0031] The two aspects of the invention and their characteristics can be combined together.

[0032] The benefits provided by the invention are numerous and include, in particular:

[0033] - improved accommodation of displacements applied to the interfaces of the reducer,

[0034] - a reduction in satellite overloads,

[0035] - a reduction in the mass of the satellite carrier,

[0036] - an improvement in the dynamic behavior of the satellite carrier,

[0037] - etc.

[0038] The present invention is compatible with: - of a single-stage or multi-stage reducer; - of a planetary, epicycloidal or differential reducer; - of straight, helical or chevron teeth; - of any type of one-piece satellite carrier or of the cage and cage carrier type; - of all types of satellite guidance bearings, such as rolling element bearings or hydrodynamic.

[0039] The satellite carrier according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0040] — the bridges are formed in one piece with the first and second discs; - the convex curved portions of the inner peripheral edge extend around the bearing axes of the bearing orifices of the disc; - the convex curved portions of the inner peripheral edge have an angular extent around the central axis, which is less than an angular extent around the central axis of the concave curved portions of the inner peripheral edge; - the concave curved portions of the outer peripheral edge have an angular extent around the central axis, which is less than or equal to an angular extent around the central axis of the convex curved portions of the outer peripheral edge; - the convex curved portions of the inner peripheral edge have an angular extent around the first axis, which is equal to + / -10% of an angular extent around the central axis of the concave curved portions of the outer peripheral edge, and / or the concave curved portions of the inner peripheral edge have an angular extent around the central axis, which is equal to + / -10% of an angular extent around the central axis of the convex curved portions of the outer peripheral edge; - the apexes of the convex curved portions of the inner peripheral edge are located on a circumference centered on the central axis which has a first diameter, and the apexes of the concave curved portions of the inner peripheral edge are located on another circumference centered on the central axis which has a second diameter, half of the difference between the second and first diameters being less than or equal to a minimum radial thickness of material of the disk around its bearing orifices and at the level of the inner peripheral edge; - the apexes of the concave curved portions of the outer peripheral edge are located on a circumference centered on the central axis which has a first diameter, and the apexes of the convex curved portions of the outer peripheral edge are located on another circumference centered on the central axis which has a second diameter, half of the difference between the second and first diameters being greater than or equal to a minimum radial thickness of material of the disk around its bearing orifices and at the level of the outer peripheral edge; - the convex curved portions of the inner peripheral edge have a radius of curvature that is less than the radius of curvature of the concave curved portions of the inner peripheral edge; - the concave curved portions of the outer peripheral edge have a radius of curvature which is equal to + / -10% of the radius of curvature of the convex curved portions of the outer peripheral edge; - the satellite carrier has a maximum radial dimension at the disk orifices which is less than a maximum radial dimension of the satellite carrier between the orifices; - the concave curved portions of the inner peripheral edge are all and entirely located on the same circumference centered on the first axis; - the convex curved portions of the outer peripheral edge are all and entirely located on the same circumference centered on the first axis;

[0041] — the first plane is also a plane of symmetry for the orifices of the pair; - the second plane is also a plane of symmetry for the hole; - each of the holes has a circular shape centered on the point of intersection between the first and second planes; - each of the holes has an elliptical circular shape which includes a larger transverse dimension extending along said first plane; - each of the holes has a rectangular shape with rounded corners; - each of the holes includes a radially internal edge which is convexly curved around the first axis, a radially external edge which is concavely curved around the first axis, a first lateral edge which is convexly curved around the second axis of a first of the holes in the pair, and a second lateral edge which is convexly curved around the second axis of a second of the holes in the pair; - the disk or each disk comprising pairs of bearing holes has, circumferentially between each pair of bearing holes, at least one additional through hole which is located radially above or below the first hole, and which is cut by said first plane; - the first hole and each additional hole(s) have the same shape and dimensions; - the disk or each disk comprising pairs of bearing orifices has, circumferentially between each pair of bearing orifices, at least one through-hole, said first plane also being a plane of symmetry of this light; - the disk or each disk has a thickness of material measured in a radial direction with respect to the central axis, between an internal peripheral edge of the disk, and the first hole, which is less than a second thickness of material measured in the same direction, between the first hole and the light;

[0042] — the satellite carrier is of the monobloc type;

[0043] — the satellite carrier is of the cage and cage carrier type, the two discs and the bridges forming the cage.

[0044] The present invention also relates to a mechanical gearbox for an aircraft turbomachine, comprising a satellite carrier as described above, the gearbox further comprising:

[0045] - a solar element which is centered on the central axis and which is mounted between the disks of the carrier satellites,

[0046] - satellites which are centered on the bearing axes and mounted between the discs of the satellite carrier, the satellites being guided in rotation by bearings housed respectively in the first and second bearing holes of the disks, and

[0047] - a crown being centered on the central axis and extending around the solar and the satellites, the satellites being geared with the solar system and the corona.

[0048] The invention further relates to a turbomachine, in particular for aircraft, comprising a reducer as described above. Brief description of the figures

[0049] Other features and advantages will become apparent from the following description of a non-limiting embodiment of the invention with reference to the accompanying drawings in which:

[0050] [Fig-1] [Fig.1] is a schematic axial cross-sectional view of a turbomachine using the invention;

[0051] [Fig.2] [Fig.2] is a schematic axial cross-sectional view of a reducer mechanics;

[0052] [Fig.3] [Fig.3] is a perspective view of a cage and cage holder assembly forming a mechanical reducer satellite carrier;

[0053] [Fig.4] [Fig.4] is a partial axial cross-sectional view of a portion of the carrier satellites of the [Fig.3];

[0054] [Fig.5] [Fig.5] is a detail view of [Fig.4];

[0055] [Fig.6] [Fig.6] is a schematic front view of the satellite carrier of [Fig.3];

[0056] [Fig.7] [Fig.7] is a view similar to that of [Fig.6] and illustrates a mode of construction of a satellite carrier according to the invention;

[0057] [Fig.8] [Fig.8] is a larger scale view of part of [Fig.7];

[0058] [Fig.9] [Fig.9] is a view similar to that of [Fig.6] and illustrates another mode for the production of a satellite carrier according to the invention;

[0059] [Fig. 10] [Fig. 10] is a larger scale view of part of [Fig. 9];

[0060] [Fig. 11] [Fig. 11] is a view similar to that of [Fig. 10] and illustrating a variant embodiment of the invention;

[0061] [Fig.12] [Fig.12] is a view similar to that of [Fig.10] and illustrating another variant of the embodiment of the invention;

[0062] [Fig. 13] [Fig. 13] is a view similar to that of [Fig. 10] and illustrating another variant embodiment of the invention. Detailed description of the invention

[0063] Figure 1 describes a turbomachine 1 which conventionally comprises a fan S, a low-pressure compressor 1a, a high-pressure compressor 1b, an annular combustion chamber 1e, a high-pressure turbine Id, a low-pressure turbine 1e, and an exhaust nozzle Ih. The high-pressure compressor 1b and the high-pressure turbine Id are connected by a high-pressure shaft 2 and together form a high-pressure (HP) housing. The low-pressure compressor 1a and the low-pressure turbine 1e are connected by a low-pressure shaft 3 and together form a low-pressure (LP) housing.

[0064] The blower S is driven by a blower shaft 4 which is connected to the BP shaft 3 by means of a mechanical reducer 10. This reducer 10 is generally of the planetary or epicyclic type.

[0065] Although the following description relates to a planetary or epicycloidal type reducer, it also applies to a mechanical differential in which its three essential components, namely the planet carrier, the crown and the sun gear, are mobile in rotation, the rotational speed of one of these components depending in particular on the difference in speeds of the other two components.

[0066] The reducer 10 is positioned in the upstream part of the turbomachine. A fixed structure schematically comprising, here, an upstream part 5a and a downstream part 5b which make up the motor or stator housing 5 is arranged to form an enclosure E surrounding the reducer 10. This enclosure E is here closed upstream by seals at the level of a bearing allowing the passage of the blower shaft 4, and downstream by seals at the level of the passage of the BP shaft 3.

[0067] Figure 1 shows part of a gearbox 10 which can take the form of different architectures depending on whether certain parts are fixed or rotating. At the input, the gearbox 10 is connected to the shaft BP 3, for example via splines 7. Thus, the shaft BP 3 drives a planetary gear called the sun gear 11. Conventionally, the sun gear 11, whose axis of rotation coincides with the X-axis of the turbomachine 1, drives a series of gears called sun gears 12, which are equally spaced circumferentially on the same diameter around the axis of rotation X. This diameter is equal to twice the operating center distance between the sun gear 11 and the sun gears 12. The number of sun gears 12 is generally defined between three and seven for this type of application.

[0068] The set of satellites 12 is held by a chassis called satellite carrier s 12. Each satellite 12 rotates around its own Y axis, and meshes with the ring 14.

[0069] At the output of the reducer 10, we have: • In an epicyclic configuration, the set of satellites 12 drives the planet carrier 13 in rotation around the X-axis of the turbomachine. The ring gear 14 is fixed to the motor or stator housing 5 via a ring carrier 15 and the planet carrier 12 is fixed to the fan shaft 4. • In a planetary configuration, the set of satellites 12 is held by a satellite carrier 12 which is fixed to the motor or stator housing 5. Each satellite drives the ring which is brought to the blower shaft 4 via a ring carrier 15.

[0070] Each satellite 12 is mounted to rotate freely by means of a bearing 8 about a Y-axis. The Y-axes of rotation of the satellites 12 are distributed around the X-axis and parallel to this X-axis. The bearings 8 are, for example, of the roller bearing or hydrodynamic bearing type. Each bearing 8 is mounted on a physical axis 13a of the satellite carrier 12, and all these physical axes 13a are positioned relative to each other by means of one or more structural frames of the satellite carrier 12. There is a The number of physical axes 13a and bearings 8 equals the number of satellites 12. For reasons of operation, assembly, manufacturing, control, repair or replacement, the axes 13a and the chassis can be separated into several parts.

[0071] For the same reasons mentioned above, the teeth of a gearbox can be separated into several helices. In our example, we detail the operation of a multi-helix gearbox 10 with a ring gear separated into two half-ring gears: • A front half-crown 14a consisting of a rim 14aa and a mounting half-flange 14ab. The front helix of the reduction gear is located on the rim 14aa. This front helix meshes with that of the satellite 12, which in turn meshes with that of the solar 11. • A rear half-crown 14b consisting of a rim 14ba and a mounting flange half 14bb. The rear helix of the reduction gear is located on the rim 14ba. This rear helix meshes with that of the satellite 12, which in turn meshes with that of the solar 11.

[0072] The front sprocket 14a mounting half-flange and the rear sprocket 14b mounting half-flange form the sprocket mounting flange 14c. The sprocket 14 is attached to the sprocket carrier 15 by joining the sprocket mounting flange 14c and the sprocket carrier mounting flange 15a using, for example, a bolted assembly. In the following, a half-flange may be referred to as a flange.

[0073] The arrows in [Fig. 1] describe the oil flow in the gearbox 10. The oil enters the gearbox 10 from the stator section 5 into the distributor 16 by various means, which will not be specified in this view because they are specific to one or more types of architecture. The distributor 16 is divided into two parts, each generally repeated with the same number of planetary gears. The injectors 17a lubricate the gear teeth, and the arms 17b lubricate the bearings 8. The oil is supplied to the injector 17a and exits through the end 17c to lubricate the gear teeth. The oil is also supplied to each arm 17b and flows through the supply mouth 17d of the bearing 8. The oil then flows through the shaft 13a into one or more buffer zones 13b and then out through ports 13c to lubricate the bearings 8 of the satellites.

[0074] The satellite carrier 13 of [Fig.2] is formed from a single piece in the example shown.

[0075] In figures 3 to 5, the elements already described above are designated by the same references augmented by one hundred.

[0076] Figures 3 to 5 represent a particular satellite carrier technology 113, this satellite carrier comprising a cage 120 and a cage carrier 122 connected by ball joints.

[0077] The cage 120 comprises two radial annular discs or walls 136, 138 which are parallel to each other and perpendicular to the X axis, as well as a cylindrical wall 140 which extends between the external peripheries of these discs or walls 136, 138.

[0078] The cylindrical wall 140 is of the double-skinned type and comprises an outer skin 140a interrupted by openings 143 and an inner skin 140b interrupted by the same openings 143. The outer skin 140a, separated by five openings 143, forms five outer brackets, and the inner skin 140b, separated by five openings 143, forms five inner brackets. Each pair of lower and upper brackets forms a yoke to receive the finger 182 of the cage holder 122. In other words, the brackets of each pair define a recess 180 for receiving a finger 182 of the cage holder 122. The brackets provide the structural connection between the walls 136 and 138. Oblong openings 180a are made in at least one of the walls 136 and 138 such as to allow the finger 182 to pass between the inner and outer brackets. These 180a lights open into the 180 housing units.

[0079] The cage 120 thus comprises an annular row of housings 180. These housings 180 receive the axial fingers 182 which are integral with an annular wall 182a substantially radial to the cage holder 122. The wall 182a is located at an axial end of the cage holder 122. The fingers 182 extend axially from the wall 182a and are engaged by axial translation in the housings 180.

[0080] Each finger 182 includes, substantially in its middle, a mounting ring 184 for the ball joint 186 intended to be traversed by a cylindrical pin 188 carried by the cage 120.

[0081] The ring 184 has a substantially radial orientation with respect to the X axis. It has a generally cylindrical shape. The cage 120 and the ball joint 186 have a thickness, measured in a radial direction with respect to the X axis, which is less than the inter-bridge distance or the radial thickness of the oblong slot 180a, so that they can be engaged in this housing concomitantly with the support finger 182 for these parts.

[0082] Each housing 180 is traversed by a pin 188 which has a substantially radial orientation with respect to the X-axis. Each pin 188 comprises a cylindrical body 188a connected at an axial end, here radially internal, to an external annular collar 188b. The pin 188 is engaged here by radial translation from the inside through radial holes in the bridges, its collar 188b being intended to bear radially against a flat face 191 of the outer bridge of the cage 120. After insertion of the pin 188 into the holes in the bridges, until the collar 188b bears against the outer bridge, the collar 188b is fixed to this bridge, for example by screwing.

[0083] Fig. 6 shows a detail of the discs or walls 136, 138 of the satellite carrier 113. In these figures, it can be seen that each of the walls 136, 138 includes first orifices 192, 174 centered respectively on the Y axes of rotation of the gearbox's satellites. There are five orifices 192, 194 on each of the walls 136, 138 in the example shown. The orifices 192 and 194 do not necessarily have identical diameters.

[0084] When the discs or walls 136, 138 have features or recesses around an opening 192, 194, these features and recesses are generally symmetrical with respect to a plane passing through the X and Y axes of this opening. This is particularly the case for the openings 180a.

[0085] In [Fig.6] for example, it can be seen that the lights 180a are arranged symmetrically with respect to the plane P passing through the axis X of the reducer and the axis Y of the orifice 192, 194 located between these lights 180a.

[0086] The wall 136, 138 of the disc may also include fixing holes 196. These holes 196 are intended to receive fixing elements such as screws, which allow for example to fix another part on the satellite carrier s 113 such as a lubricating oil distributor for example.

[0087] When a plane H is drawn passing through the Y axes of two circumferentially adjacent orifices 192 or 194, it is observed that the openings 180a are not intersected by these planes, nor are the mounting holes 196. It is also observed that the inner peripheral edges 198 and outer peripheral edges 199 of the walls 136, 138 of the disks are perfectly circular and centered on the X axis.

[0088] The invention proposes an improvement of a satellite carrier for a mechanical gearbox of an aircraft turbomachine.

[0089] This satellite carrier can be of the monobloc type as illustrated in [Fig. 2], or of the type cage and cage holder as illustrated in figures 3 to 6. The preceding descriptions in relation to figures 2 to 6 can therefore be used to illustrate and describe the invention.

[0090] Furthermore, the satellite carrier according to the invention can equip a reducer of a turbomachine as illustrated in [Fig.1]. The preceding description in relation to [Fig.1] can therefore also be used to illustrate and describe the invention.

[0091] Figures 7 and 8 illustrate a first embodiment of a satellite carrier 213 according to the invention. This satellite carrier 213 can be of the monobloc type or of the cage 220 type and cage carrier.

[0092] In these figures, the elements already described above are designated by the same references augmented by another hundred.

[0093] In these figures, the satellite carrier s 213 comprises:

[0094] - a first disk 236 centered on the X-axis, called the first axis or central axis, and extending perpendicularly to this X axis, this first disk 236 having first bearing orifices 292 centered respectively on the Y axes, called bearing axes or second axes, which are parallel to the X axis and arranged around this X axis,

[0095] - a second disk 238 centered on the X-axis and parallel and at a distance from the disk 236, this second disk 238 having second bearing holes 294 which are respectively centered on the Y axes, and whose number is equal to the number of the first bearing holes 292, and

[0096] - bridges 296 which extend between the discs 236, 238 and connect them together, these bridges 296 being formed in one piece with the discs 236, 238.

[0097] In the figures, one of the two disks 236, 238 is visible but because of their similarities, they may have the same characteristics.

[0098] The first disc 236 is for example a front or upstream disc, and the second disc 238 is for example a rear or downstream disc, by reference to the position of the reducer in the turbomachine and to the flow of gases in the turbomachine.

[0099] Ports 292 and 294 are used to mount the satellites, and in particular the satellite guidance bearings, in the satellite carrier 213. The bearings have longitudinal ends that are housed in these ports 292 and 294. The bearings are plain (hydrodynamic) or rolling bearings, for example. These bearings are not shown in the figures.

[0100] At least one of the disks 236, 238 comprises an alternation of concave curved portions 298a, 299a and convex portions 298b, 299b on each of its peripheral edges 298, 299.

[0101] The convex curved portions 298b of the inner peripheral edge 298 and the concave curved portions 299a of the outer peripheral edge 299 are aligned radially with respect to the first axis X and extend respectively inside and outside the orifices 292, 294 of the disk 236, 238.

[0102] The concave curved portions 298a of the inner peripheral edge 298 and the convex curved portions 299b of the outer peripheral edge 299 are aligned radially with respect to the first axis X and extend between the orifices 292, 294 of the disc 236, 238.

[0103] The number of concave curved portions 298a, 299a and convex curved portions 298b, 299b of the peripheral edges 298, 299 of the disk 236, 238 is equal to the number of holes 292, 294 of this disk. This means that the number of concave curved portions 298a of edge 298 is equal to the number of convex curved portions 298b of this edge, and is equal to the number of holes 292, 294 of the disk. This also means that the number of concave curved portions 299a of edge 299 is equal to the number of convex curved portions 299b of this edge, and is equal to the number of orifices 292, 294 of the disk.

[0104] In figures 7 and 8, the following characteristics can be observed.

[0105] The convex curved portions 298b of the inner peripheral edge 298 can extend around the second axes Y of the orifices 292, 294 of the disk.

[0106] The convex curved portions 298b of the inner peripheral edge 298 can have an angular extent a around the first axis X, which is less than an angular extent [3 around the first axis X of the concave curved portions 298a of the inner peripheral edge 298.

[0107] The concave curved portions 299a of the outer peripheral edge 299 may have an angular extent y around the first axis X, which is less than or equal to an angular extent ô around the first axis X of the convex curved portions 299b of the outer peripheral edge 299.

[0108] a may be identical to y, to + / -30%, and preferably + / -10%.

[0109] [3 can be identical to 0, to + / -30%, and preferably + / -10%.

[0110] The vertices of the convex curved portions 298b of the inner peripheral edge 298 can be located on a circumference Cl centered on the first axis X which has a first diameter DI.

[0111] The concave curved portions 298a of the inner peripheral edge 298 can all and entirely be located on the circumference CL

[0112] The vertices of the concave curved portions 298a of the inner peripheral edge 298 can be located on another circumference C2 centered on the first axis X which has a second diameter C2.

[0113] Half of the difference between the second and first diameters D2, DI may be less than or equal to a minimum radial thickness El of material of the disc around its orifices 292, 294 and at the level of the internal peripheral edge 298. This thickness of material or this ligament of material is preferably reduced to the minimum necessary for the mechanical holding of the receiving orifice of the corresponding bearing.

[0114] The vertices of the concave curved portions 299a of the outer peripheral edge 299 can be located on a circumference C3 centered on the first axis X which has a first diameter D3.

[0115] The convex curved portions 299b of the outer peripheral edge 299 can all and entirely be located on the circumference C3.

[0116] The vertices of the convex curved portions 299b of the outer peripheral edge 299 are located on another circumference C4 centered on the first axis X which has a second diameter D4.

[0117] Half of the difference between the second and first diameters D3, D4 may be greater than or equal to a minimum radial thickness E2 of material of the disc 236, 238 around its orifices 292, 294 and at the level of the outer peripheral edge 299.

[0118] The convex curved portions 298b of the inner peripheral edge 298 may have a radius of curvature XI which is less than the radius of curvature (which corresponds to D2 / 2) of the concave curved portions 298b of the inner peripheral edge 298.

[0119] The concave curved portions 299a of the outer peripheral edge 299 can have a radius of curvature X2 strictly less than the radius of curvature (which corresponds to D4 / 2) of the convex curved portions 299b of the outer peripheral edge 299.

[0120] The satellite carrier 213 can have a maximum radial dimension H1 at the ports 292, 294 of the disk 236, 238 which is less than a maximum radial dimension H2 of the satellite carrier 213 between the ports 292, 294 ([Fig.7]).

[0121] Figures 9 and 10 illustrate a second embodiment of a satellite carrier s 313 according to the invention. This satellite carrier 313 can be of the monobloc type or with a cage 320 and cage carrier.

[0122] In these figures and the following ones, the elements already described above are designated by the same references augmented by a new hundred.

[0123] In these figures, the satellite carrier s 313 comprises:

[0124] - a first disk 336 centered on the X axis and extending perpendicularly to this X axis, this first disk 336 having first orifices 392 centered respectively on the Y axes which are parallel to the X axis and arranged around this X axis,

[0125] - a second disk 338 centered on the X axis and parallel and at a distance from disk 336, this second disk 338 having second orifices 394 which are respectively centered on the Y axes, and whose number is equal to the number of the first orifices 392, and

[0126] - bridges 396 which extend between the discs 336, 338 and connect them together, these bridges 396 being formed in one piece with the discs 336, 338.

[0127] In the figures, one of the two disks 236, 238 is visible but because of their similarities, they may have the same characteristics.

[0128] The first disc 336 is for example a front or upstream disc, and the second disc 338 is for example a rear or downstream disc, by reference to the position of the reducer in the turbomachine and to the flow of gases in the turbomachine.

[0129] Ports 392, 394 are used to mount the satellites, and in particular the satellite guidance bearings, in the satellite carrier 313. The bearings have longitudinal ends that are housed in these ports 392, 394. The bearings are Plain (hydrodynamic) or rolling bearings, for example. These bearings are not shown in the figures.

[0130] The orifices 392, 394 of at least one of the disks 336, 338 are arranged in pairs. These are virtual pairs, the term "pair of disks" referring to the presence of two orifices side by side or circumferentially adjacent in this application. Reference numeral B, for example, designates a pair. The number of pairs of orifices in a disk 336, 338 is equal to Nl, where N is the number of orifices 392, 394 in the disk.

[0131] Each pair of orifices 392 or 394 thus comprises two circumferentially adjacent orifices.

[0132] The disk or each disk 336, 338 comprises, between each pair of orifices 392 or 394, a first through hole 400 which is cut by a first plane PI extending radially with respect to the first axis X and located at equal distances from the orifices 392 or 394 of the pair, and which is cut by a second plane P2 passing through the second axes Y of these orifices /

[0133] The first PI plane is advantageously a first plane of symmetry for the hole 400. This first PI plane can also be a plane of symmetry for the lights 380a.

[0134] The second plane P2 can also be a plane of symmetry for the hole 400.

[0135] Figures 10 to 13 illustrate several variant embodiments of the holes 400.

[0136] In [Fig.10], each of the holes 400 comprises a radially internal edge 400a which is convexly curved about the first axis X, a radially external edge 400b which is concavely curved about the first axis X, a first lateral edge 400c which is convexly curved about the second axis Y of a first of the orifices 392 or 394 of the pair, and a second lateral edge 400d which is convexly curved about the second axis Y of a second of the orifices 392 or 394 of the pair.

[0137] In [Fig. 11], each of the holes 400 has an elliptical circular shape which includes a larger transverse dimension U1 extending along the first plane PL

[0138] In [Fig.12], each of the 400 holes has a rectangular shape with rounded corners.

[0139] In [Fig. 13], each of the 400 holes has a circular shape centered on the point or the line of intersection W between the first and second planes PI, P2.

[0140] As can be seen in the variant of [Fig. 13], the disk or each disk 336, 338 may have, between each pair of holes 392, 394, at least one additional through hole 401, 402 which is located radially above or below the first hole 400, and which is intersected by the first plane PL

[0141] The first hole 400 and the additional hole or holes 400a, 400b have the same shape and dimensions.

[0142] As can be seen in the drawings, the disc or each disc 336, 338 may have, between each pair of orifices 392, 394, at least one light 380a traversing, the first plane PI also being a plane of symmetry of this light 380a.

[0143] The disk or each disk 336, 338 has a material thickness ZI measured in the radial direction with respect to the first axis X, between an internal peripheral edge 398 of the disk, and the first hole 400, which is preferably less than a second material thickness Z2 measured in the same direction, between the first hole 400 and the light 380a.

[0144] The invention provides several advantages including a reduction in the local stiffness of the planet carrier in order to reduce the aforementioned overload and the overall mass of the planet carrier and the reducer.

Claims

1. Demands Satellite carrier (213, 313) for a mechanical gearbox (10, 110) of an aircraft turbomachine (1), this satellite carrier (213, 313) comprising: - a first disk (236, 336) centered on a central axis (X) and extending perpendicularly to this central axis (X), this first disk (236, 336) having first bearing orifices (292, 392) centered respectively on bearing axes (Y) which are distributed circumferentially around the central axis (X) and parallel to this central axis (X), - a second disk (238, 338) centered on the central axis (X) and extending parallel and axially at a distance from the first disk (236, 336), this second disk (238, 338) having second bearing ports (294, 394) which are respectively centered on the bearing axes (Y), the number of second bearing ports (294, 394) being equal to the number of first bearing ports (292, 392), - bridges (296, 396) which extend between the first and second disks (236, 238, 336, 338) and connect them together, and the satellite carrier being characterized in that: - at least one of the disks (236, 238, 336, 338) comprises an alternation of concave (298a, 299a) and convex (298b, 299b) curved portions on each of the inner and outer peripheral edges (298, 299) of the disk (236, 238, 336, 338), the convex curved portions (298b) of the inner peripheral edge (298) and the concave curved portions (299a) of the outer peripheral edge (299) being radially aligned with respect to the central axis (X) and extending radially inward and outward respectively from the bearing holes (292, 294) of the disk (236, 238), and the concave curved portions (298a) of the inner peripheral edge (298) and the convex curved portions (299b) of the outer peripheral edge (299) being radially aligned with respect to the central axis (X) and the numbers of the concave and convex curved portions (298a, 298b, 299, 299b) of the inner and outer peripheral edges (298, 299) of the disk (236,238) being equal to the number of bearing holes (292, 294) of this disk (236, 238), and / or, - the bearing ports (392, 394) of at least one of the disks (336, 338) are distributed in pairs, each pair of bearing ports (392, 394) comprising two circumferentially adjacent bearing ports (392, 394), the disk or each disk (336, 338) comprising pairs of bearing ports (392, 394) comprising, between each pair of bearing ports (392, 394), a first through hole (400) which is intersected by a first plane (PI) extending radially with respect to the central axis (X) and located at equal distances from the bearing ports (392, 394) of the pair, and which is intersected by a second plane (P2) passing through the bearing axes (Y) of this pair of bearing ports (392, 394), the first plane (PI) being a first plane of symmetry for the hole (400).

2. Satellite carrier (213) according to claim 1, wherein the convex curved portions (298b) of the inner peripheral edge (298) extend around the bearing axes (Y) of the bearing ports (292, 294) of the disk (236, 238).

3. Satellite carrier (213) according to claim 1 or 2, wherein the convex curved portions (298b) of the inner peripheral edge (298) have an angular extent (a) around the central axis (X), which is less than an angular extent (|3) around the central axis of the concave curved portions (299a) of the inner peripheral edge (299), and / or - the concave curved portions (299a) of the outer peripheral edge (299) have an angular extent (y) around the central axis (X), which is less than or equal to an angular extent (d) around the central axis of the convex curved portions (299b) of the outer peripheral edge (299).

4. Satellite carrier (213) according to any one of claims 1 to 3, wherein the convex curved portions (298b) of the inner peripheral edge (298) have an angular extent (a) around the central axis (X), which is equal to + / -10% of an angular extent (ip) around the central axis (X) of the concave curved portions (299a) of the outer peripheral edge (299), and / or the concave curved portions (298a) of the inner peripheral edge (298) have an angular extent (|3) around the central axis (X), which is equal to + / -10% of an angular extent (ô) around the central axis (X) of the convex curved portions (299b) of the outer peripheral edge (299).

5. Planet carrier (213) according to any one of claims 1 to 4, wherein: - the apexes of the convex curved portions (298b) of the inner peripheral edge (298) are located on a circumference (C1) centered on the central axis (C1) which has a first diameter (D1), and the apexes of the concave curved portions (298a) of the inner peripheral edge (298) are located on another circumference (C2) centered on the central axis (X) which has a second diameter (D2), the difference between the second and first diameters (D1, D2) being less than or equal to a minimum radial thickness (E1) of material of the disk (236, 238) around its bearing holes (292, 294) and at the outer peripheral edge (298), and / or - the apexes of the concave curved portions (299a) of the outer peripheral edge (299) are located on a circumference (C3) centered on the central axis (X) which has a first diameter (D3),and the apexes of the convex curved portions (299b) of the outer peripheral edge (299) are located on another circumference (C2) centered on the central axis (X) which has a second diameter (D4), the difference between the second and first diameters (D3, D4) being greater than or equal to a minimum radial thickness (E2) of material of the disk (236, 238) around its bearing orifices (392, 394) and at the level of the outer peripheral edge (299).

6. Satellite carrier (313) according to any one of the preceding claims, wherein the second plane (P2) is also a plane of symmetry for the hole (400).

7. Planet carrier (313) according to any one of the preceding claims, wherein the disc or each disc (336, 338) having pairs of bearing holes (392, 394) has, circumferentially between each pair of bearing holes (392, 394), at least one additional through hole (401, 402) which is located radially above or below the first hole (400), and which is intersected by said first plane (PD-

8. Satellite carrier (313) according to claim 7, wherein the first hole (400) and the additional hole or holes (401, 402) have the same shape and dimensions.

9. Satellite carrier (313) according to any one of the preceding claims, wherein the or each disk (336, 338) comprising pairs bearing orifices (392, 394) includes, circumferentially between each pair of bearing orifices (392, 394), at least one through light (380a), said first plane (PI) also being a plane of symmetry of this light (380a).

10. Satellite carrier (313) according to claim 9, wherein the or each disk (336, 338) has a material thickness (Z1) measured in the radial direction with respect to the central axis (X), between an internal peripheral edge of the disk (336, 338), and the first hole (400), which is less than a second material thickness (Z2) measured in the same direction, between the first hole (400) and the light (380a).

11. A mechanical gearbox (10, 110) for an aircraft turbomachine, comprising a satellite carrier (213, 313) according to any one of the preceding claims, the gearbox further comprising: - a sun gear (11) centered on the central axis (X) and mounted between the disks (236, 238, 336, 338) of the satellite carrier (213, 313), - satellites (12) centered on the bearing axes (Y) and mounted between the disks (236, 238, 336, 338) of the satellite carrier (213, 313), the satellites (12) being guided in rotation by bearings (8) housed respectively in the first and second bearing holes (292, 294, 392, 394) of the disks (236, 238, 336, 338), and - a crown (14) being centered on the central axis (X) and extending around the solar (11) and the satellites (12), the satellites (12) being meshed with the solar (11) and the crown (14).

12. Turbomachine (1), in particular aircraft, comprising a reducer (10, 110) according to claim 11.

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