SATELLITE MOUNT FOR A MECHANICAL REDUCTION GEARBOX ON AN AIRCRAFT TURBOMACHINE

Abstract

A satellite carrier (213) for a mechanical gearbox (10) of an aircraft turbomachine (1), this satellite carrier (213) comprising: - a first disc (236) having first orifices (292), - a second disc (238) having second orifices (294) aligned with the first orifices (292), the first and second discs (236, 238) comprising first annular faces (236a) opposite each other, - bridges (296) which extend between the first and second discs (236, 238) and connect them together, the bridges (296) being formed in one piece with the first and second discs (236, 238), characterized in that at least one of said first faces (236a) has recesses (298) which are arranged next to said orifices (292, 294) and which are not symmetrical. Figure for the abbreviation: Figure 7

Description

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

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

[0002] The state of the art includes in particular documents FR-A1-2 987 416, FR-Al-2 853 382, ​​FR-A1-3 041 054, FR-A1-3 052 113, 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 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 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, 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] 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 ring constitutes the output shaft of the device which rotates in the opposite direction of 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.

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

[0010] Gear reducers can be composed of one or more meshing stages. This meshing is achieved in various ways, such as by contact, friction, or magnetic field. There are several types of contact meshing, such as with spur 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 includes 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 generate tilting of the planets, leading to degradation of the meshing, and risks of the appearance of an asymmetrical oil film in the case of the use of plain or hydrodynamic bearings for guiding the planets, or risks of generating tilting of the rollers in the case of the use of roller bearings for guiding the planets.

[0014] These stresses and deformations must be rebalanced in order to limit or even cancel these effects.

[0015] The present invention offers a solution to this need, which is simple, effective and economical. Summary of the invention

[0016] The invention relates to a cage for a satellite carrier of a mechanical gearbox of an aircraft turbomachine, this cage being formed of a single piece and comprising:

[0017] - a first disk centered on a central axis and extending radially and around it With respect to this central axis, this first disk has initial bearing orifices centered respectively on bearing axes which are distributed circumferentially around the central axis and parallel to this central axis,

[0018] - a second disk centered on the central axis and extending parallel and axially to distance from the first disc, this second disc having second orifices of bearings which are respectively centered on the bearing axes, the number of secondary bearing holes being equal to the number of primary bearing holes,

[0019] the first and second disks comprising first annular faces axially opposite each other,

[0020] - bridges that extend between the first and second discs and connect them between them, the bridges being formed in one piece with the first and second discs,

[0021] characterized in that at least one of said first faces has a recess pattern disposed next to one of said bearing orifices, the recess pattern having a curved shape extending along an arc of a circle around the bearing orifice at the level of which the recess pattern is located, and preferably the recess pattern extending preferably in a non-symmetrical manner with respect to a radial plane passing through the central axis and the bearing axis of this orifice.

[0022] 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 misalignment or asymmetry, is thus reduced. This is made possible by the recess patterns formed in at least one of the disks. These recess patterns make it possible to locally reduce the stiffness (and therefore increase the flexibility) of the disk and thus adjust the stiffness (flexibility) of the disks relative to each other. The more locally flexible a disk is, the more the softened area is able to deform and absorb some of the energy related to the transmission of forces. The recess patterns therefore make it possible to adjust the deformations of one of the disks relative to the other disk, to limit their impact on the bearings.

[0023] The recess patterns are located at the mounting holes of the satellite bearings through which the forces are transmitted. These recess patterns are preferably arranged asymmetrically with respect to the axis of the holes and are advantageously positioned according to the direction of the forces transmitted by the satellites. The recess patterns are therefore advantageously positioned according to the direction of rotation of the satellites.

[0024] The benefits provided by the invention are numerous and include, in particular:

[0025] - a reduction in the misalignment of the satellite gears with less constraints on these teeth,

[0026] - a reduction in misalignment on the guide bearings with less constraints placed upon them

[0027] - a reduction in satellite misalignments,

[0028] - a reduction in the mass of the satellite carrier,

[0029] - etc.

[0030] The present invention is compatible with:

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037] - 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. The satellite carrier according to the invention may comprise one or more of the following features, taken individually or in combination with each other: — the hollowing patterns include hollows; a hollowing pattern may include one or more hollows; — the recesses or recess patterns are cut or crossed by circumferences centered on the first axis and passing through these openings; — the recesses or recess patterns extend around the openings or are distributed around these openings; - the recess pattern has a single recess or has a single series of recesses located on one side of the bearing opening; - the recess pattern comprises two recesses (298) or two series of recesses located on either side of this bearing orifice; - the two recesses or the two series of recesses are different in their shapes and / or dimensions; - the cutout pattern is an oblong curved slit, or is a series of holes extending along a curved line; - the oblong slot comprises a main branch which extends in an elongated and curved manner around the bearing orifice, and secondary branches which extend transversely opposite the main branch; - there are three secondary branches, two secondary branches extending to the longitudinal ends of the main branch, and the third secondary branch extending to the middle of the main branch; - the cutout pattern includes between two and ten holes; - at least some of the recesses in the recess pattern are not through-holes (or blind) in the axial direction; — at least some of the recesses in the recess pattern are through-holes in the axial direction; — at least some of the recesses in the recess pattern have a variable depth; - at least some of the recesses in the recess pattern are arranged symmetrically with respect to other identical recesses located on a second face axially opposite to the first face of the disk containing these recesses;

[0038] — the satellite carrier is of the monobloc type,

[0039] — the satellite carrier is of the cage and cage carrier type, the two discs and the bridges forming the cage.

[0040] The present invention also relates to a mechanical gearbox for an aircraft turbomachine, comprising a satellite carrier according to one of the preceding claims, the gearbox further comprising:

[0041] - a solar element which is centered on the central axis and which is mounted between the disks of the carrier satellites,

[0042] - satellites which are centered on the bearing axes and mounted between the disks of the satellite carriers, the satellites being guided in rotation by bearings whose opposite axial ends are housed respectively in the first and second bearing holes of the disks, and

[0043] - a crown centered on the central axis and extending around the solar and sa tellites, the satellites being meshed with the solar system and the corona.

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

[0045] 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:

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

[0047] [Fig.2] [Fig.2] is a schematic axial cross-sectional view of a reducer mechanics;

[0048] [Fig.3] [Fig.3] is a perspective view of a cage and cage carrier assembly forming a mechanical reducer satellite carrier;

[0049] [Fig.4] [Fig.4] is a partial axial cross-sectional view of a portion of the carrier tellites of the [Fig.3];

[0050] [Fig.5] [Fig.5] is a detail view of [Fig.4];

[0051] [Fig.6] [Fig.6] is a partial schematic front view of the satellite carrier of the [Fig.3];

[0052] [Fig.7] [Fig.7] is a view similar to that of [Fig.6] and illustrates a method of construction of a satellite carrier according to the invention;

[0053] [Fig.8] [Fig.8] is a view similar to that of [Fig.6] and illustrates a variant embodiment of a satellite carrier according to the invention;

[0054] [Fig.9] [Fig.9] is a view similar to that of [Fig.6] and illustrates another variant of the embodiment of a satellite carrier according to the invention;

[0055] [Fig. 10] [Fig. 10] is a view similar to that of [Fig. 6] and illustrates a variant embodiment of a satellite carrier according to the invention;

[0056] [Fig. 11] [Fig. 11] is a partial schematic cross-sectional and perspective view of the satellite carrier of [Fig. 10];

[0057] [Fig. 12] [Fig. 12] is a view similar to that of [Fig. 11] and illustrates another variant of the embodiment;

[0058] [Fig. 13] [Fig. 13] is a view similar to that of [Fig. 6] and illustrates another variant of an embodiment of a satellite carrier according to the invention;

[0059] [Fig. 14] [Fig. 14] is a view similar to that of [Fig. 6] and illustrates another embodiment of a satellite carrier according to the invention; and

[0060] [Fig. 15] [Fig. 15] is a view similar to that of [Fig. 6] and illustrates another variant of an embodiment of a satellite carrier according to the invention. Detailed description of the invention

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] Figure 1 shows part of a reducer 10 which can take the form of dif Different architectures are used depending on whether certain parts are fixed or rotating. At the input, the reducer 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. Typically, 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 evenly spaced around the same diameter around the X-axis. 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 between three and seven for this type of application.

[0066] The set of satellites 12 is held by a frame called a satellite carrier 12. Each satellite 12 rotates around its own Y axis, and meshes with the ring 14.

[0067] 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.

[0068] 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 number of physical axes 13a and bearings 8 equal to the number of satellites 12. For reasons of operation, assembly, manufacturing, inspection, repair, or replacement, the axes 13a and the frame may be separated into several parts.

[0069] 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 half-flange 14bb. The rear propeller of the Gearbox teeth. This rear helix meshes with that of satellite 12, which meshes with that of solar 11.

[0070] 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.

[0071] 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.

[0072] The satellite carrier 13 of [Fig.2] is formed from a single piece in the example shown.

[0073] In figures 3 to 6, the elements already described above are designated by the same references augmented by one hundred.

[0074] 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.

[0075] 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 radial annular walls 136, 138.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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 concurrently with the support finger 182 for these parts.

[0080] 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.

[0081] Figure 6 shows a detail of the disks or walls 136, 138 of the planet carrier 113. In these figures, it can be seen that the wall 138 comprises first orifices 192 centered respectively on the Y axes of rotation of the planets of the gearbox. There are five of these orifices 192 in the example shown. The wall 136 comprises second orifices 194 centered respectively on the Y axes and therefore aligned with the orifices 192. There are also five of these orifices 194 in the example shown.

[0082] When the disks or walls 136, 138 have features around an orifice, these features are generally symmetrical with respect to a plane passing through the X and Y axes of that orifice. This is particularly the case for the slots 180a. In [Fig. 6], for example, it can be seen that the slots 180a are arranged parallel to the plane P passing through the X axis of the reducer and the Y axis of the orifice 194 located between these slots 180a.

[0083] The invention proposes an improvement of a planet carrier for a reducer aircraft turbomachinery mechanics.

[0084] This satellite carrier can be of the monobloc type as illustrated in [Fig.2], or of the cage and cage carrier type 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.

[0085] Furthermore, the planet carrier according to the invention can be fitted to a gearbox 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.

[0086] Figures 7 to 15 illustrate several embodiments of a satellite carrier according to the invention.

[0087] In these figures and the following ones, the elements already described above are designated by the same references augmented by at least one more hundred.

[0088] In these figures, the satellite carrier s 213 comprises:

[0089] - a first disk 236 centered on the X-axis, called the central axis, and extending ra- diamentally and around with respect to this central axis X, this first disk 236 having first bearing orifices 292 centered respectively on the bearing axes Y which are distributed circumferentially around the central axis X and parallel to this central axis X,

[0090] - a second disk 238 centered on the central axis X and parallel and axially at a distance of the disk 236, this second disk 238 having second bearing holes 294 which are respectively centered on the bearing axes Y, and whose number is equal to the number of the first bearing holes 292, and

[0091] - 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.

[0092] 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.

[0093] 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 Figures 7 to 15.

[0094] The disks 236, 238 comprise first annular faces axially opposite each other. The disk 236 thus comprises an annular face 236a which is opposite an annular face of the disk 238, the annular face of the disk 238 not being visible in the drawings and therefore not referenced.

[0095] According to the invention, at least one of these faces of the discs has a recess pattern 298 arranged next to one of said bearing holes 292, 294.

[0096] The or each recess pattern comprises one or more recesses.

[0097] In the rest of the description, "hollow(s)" and "hollow pattern(s)" will be used to refer to the same thing.

[0098] The recesses 298 have the function of compensating for stresses and deformations in order to limit or even eliminate the tilting of the satellites and their bearings in operation.

[0099] These recesses 298 are preferably cut or crossed by circumferences centered on the X axis and passing through these orifices 292, 294. This means that the recesses are not located radially inside the orifices 292, 294, nor radially outside these orifices (because in this case they would not be cut by circumferences passing through these orifices), but are rather located on the sides of the orifices or even between these orifices.

[0100] These recesses 298 each have a general shape curved around the orifice 292, 294 at which the recess 298 is located, and around the Y axis of this orifice 292, 294. Alternatively, these recesses 298 are distributed to have a general shape curved around the orifice 292, 294 at which they are located, and around the Y axis of this orifice 292, 294.

[0101] Furthermore, the recess(s) 298 associated with each of the orifices 292, 294 are preferably arranged in a non-symmetrical manner with respect to a plane P passing through the X axis as well as the Y axis of this orifice 292, 294.

[0102] Figure 7 shows a first embodiment of the satellite carrier 213 in which the face 236a of the disk 236 comprises two recesses 298 of generally curved shape (like a slot) around each of the orifices 292 of the disk 236. A first recess 298a extends around each orifice 292 and around the Y-axis of this orifice 292, at a radial distance RI from the peripheral edge of this orifice. This first recess 298a has a width L1 and an angular extent EL. A second recess 298b extends around each orifice 292 and around the Y-axis of this orifice 292, at a radial distance R2 from the peripheral edge of this orifice. This recess 298b has a width L2 and an angular extent E2.

[0103] The recesses are here diametrically opposed with respect to the Y axis of the orifice 292.

[0104] In the example shown, RI is less than R2. L1 is greater than L2. El is less than E2.

[0105] The recesses 298a, 298b are preferably cut or crossed by circumferences Cl, C2 centered on the X axis and passing through the orifices 292. In practice, a multitude of circumferences centered on the X axis pass through the orifices 292.

[0106] These recesses 298a, 298b are arranged asymmetrically with respect to plane P. They are not even symmetrical with respect to each other and with respect to the Y axis or with respect to a plane passing through this axis.

[0107] Figure 8 shows an alternative embodiment of Figure 7 in which the recess 298a can be seen to have a depth U1 that is either constant or variable. In yet another alternative, the recesses could be axially through-holes and thus traverse the entire thickness of the disk axially, unlike those illustrated in Figures 7 and 8, which are of the non-through or blind type.

[0108] Fig. 9 shows an alternative embodiment of the satellite carrier 213 in which the face 236a of the disk 236 includes several recesses 298c which are distributed to have a general curved shape around each of the orifices 292 of the disk 236. There are three recesses 298c, and in the example shown they are circular holes, either through or non-through.

[0109] There are no recesses diametrically opposed to the recesses 298c, with respect to the Y axis of the orifice 292.

[0110] The set of recesses 298c has a width L3 and an angular extent E3, and is located at a radial distance R3 from the edge of the orifice 292.

[0111] The recesses 298c are preferably cut by circumferences Cl, C2 centered on the axis X and passing through the orifices 292. These recesses 298c are arranged asymmetrically with respect to the plane P.

[0112] Fig. 10 shows another embodiment of the satellite carrier 213 in which the face 236a of the disk 236 includes a single recess 298d which has a general curved shape around each of the orifices 292 of the disk 236.

[0113] There is no recess diametrically opposite to this recess 298d, with respect to the Y axis of the orifice 292.

[0114] The recess 298d has a width L4 and an angular extent E4, and is located at a radial distance R4 from the edge of the orifice 292. It can be seen in the drawings that R4 is significantly greater than RI, R2 or R3, or even greater than the radius DI of the orifices 294 of the other disk 238.

[0115] The recess 298d is preferably cut by circumferences Cl, C2 centered on the X axis and passing through the orifices 292. This recess 298d is arranged in a non-symmetrical manner with respect to the plane P.

[0116] [Fig. 11] is a cross-sectional view of [Fig. 10] and shows the depth U2 of the recess 298d. It also shows that the face 236b of the disk 236, which is opposite the face 236a, does not include a recess in that area.

[0117] In the variant illustrated in [Fig. 12], the face 236b of the disk 236 includes a recess 298d' which may be identical to the recess 298d and symmetric with respect to a plane H passing through the middle of the disk 236 and perpendicular to the axes X, Y.

[0118] Figures 13 to 15 show other embodiment variants in which the recesses are located on the disk 238 and are of the through or through type.

[0119] In [Fig.13], the disk 238 includes several recesses 298e which are distributed to have a general curved shape around each of the orifices 294 of the disk 238. The recesses 298e are four in number and are circular holes in the example shown.

[0120] The set of recesses 298e has a width L5 and an angular extent E5, and is located at a radial distance R5 from the edge of the orifice 294.

[0121] The recesses 298e are preferably cut by circumferences Cl, C2 centered on the X axis and passing through the orifices 294. These recesses 298e are arranged asymmetrically with respect to the plane P.

[0122] In [Fig. 14], the disk 238 includes several recesses 298f which are distributed to have a generally curved shape around each of the orifices 294 of the disk 238. There are five recesses 298f, which are circular holes in the example shown. They are distributed along two curved lines extending around the Y-axis, with two of the recesses located on an outer line SI and the other three located on an outer line S2 and arranged in a staggered pattern with respect to the two recesses located on line SL.

[0123] The set of recesses 298f has a width L6 and an angular extent E6, and is located at a radial distance R6 from the edge of the orifice 294.

[0124] The recesses 298f are preferably cut by circumferences Cl, C2 centered on the axis X and passing through the orifices 294. These recesses 298f are arranged asymmetrically with respect to the plane P.

[0125] In [Fig.15], the disc 238 includes a single recess 298g which has a generally curved shape around each of the orifices 294 of the disc 238. This recess 298g is in the form of an elongated and curved slot.

[0126] The slot comprises a main branch 298g1 elongated and curved around the orifice 294, and secondary branches 298g2, 298g3 perpendicular to the main branch 298g1 and connected to it. There are three secondary branches 298g2, 298g3, two of which are connected to the longitudinal ends of the main branch 298g1, and the third secondary branch 298g3 is connected to the middle of the main branch 298g1.

[0127] The slot has a maximum width L7 and an angular extent E7, and is located at a radial distance R7 from the edge of the orifice 294.

[0128] In all modes and variants of embodiments, the recesses 298 create zones of flexibility, i.e. local flexibility, around the orifices 292, 294 of the discs 236, 238. The level of flexibility can be adjusted by adjusting the dimensions of the recesses 298, and in particular by adjusting their width, their angular extent, their depth or the remaining thickness of material of the disc (by the presence of a symmetrical recess for example - [Fig. 12]), etc.

[0129] The recesses 298 are advantageously arranged according to the areas of application of the forces, which depend in particular on the direction of rotation of the satellites. Figures 7 to 15 show a direction Fl of application of the forces and a direction F2 of rotation of the satellites. It can be seen that the recesses, or at least the recesses with the largest dimensions, are located at the areas of application of the forces.

Claims

Claims

1. Planet carrier (213) for a mechanical reducer (10) of an aircraft turbomachine (1), this planet carrier (213) comprising: - a first disc (236) centered on a central axis (X) and extending radially and around with respect to this central axis (X), this first disc (236) comprising first bearing orifices (292) centered respectively on bearing axes (Y) which are distributed circumferentially around the central axis (X) and parallel to this central axis (X), - a second disc (238) centered on the central axis (X) and extending parallel and axially at a distance from the first disc (236), this second disc (238) comprising second bearing orifices (294) which are respectively centered on the bearing axes (Y), the number of second bearing holes (294) being equal to the number of first bearing holes (292), the first and second discs (236,238) comprising first faces (236a) which extend radially and are arranged axially opposite each other, - bridges (296) which extend between the first and second discs (236, 238) and connect them together, the bridges (296) being formed in one piece with the first and second discs (236, 238), characterized in that at least one of said first faces (236a) comprises a recess pattern (298) arranged next to one of said bearing orifices (292, 294), the recess pattern having a generally curved shape extending in an arc of a circle around the bearing orifice (292, 294) at which the recess pattern (298) is located, and preferably the recess pattern (298) extending non-symmetrically with respect to a radial plane (P) passing through the central axis (X) and the bearing axis (Y) of this orifice (292, 294).,

2. The planet carrier (213) of claim 1, wherein the recess pattern (298) has a single recess (298) or has a single series of recesses located on one side of the bearing hole (292, 294).

3. A planet carrier (213) according to claim 1, wherein the recess pattern comprises two recesses (298) or two sets of recesses located on either side of said bearing orifice (292, 294).

4. A planet carrier (213) according to claim 3, wherein the two recesses (298) or the two series of recesses are different by their shapes and / or their dimensions.

5. A planet carrier (213) according to any preceding claim, wherein the recess pattern is a curved oblong slot, or is a series of holes extending along a curved line.

6. A planet carrier (213) according to claim 5, wherein the oblong slot comprises a main branch (298g1) which extends in an elongated and curved manner around the bearing orifice (292, 294), and secondary branches (298g2, 298g3) which extend transversely with respect to the main branch (298g1).

7. A planet carrier (213) according to claim 6, wherein the secondary branches (298g2, 298g3) are three in number, two secondary branches (298g2) extending at the longitudinal ends of the main branch (298gl), and the third secondary branch (298g3) extending in the middle of the main branch (298gl).

8. The planet carrier (213) of claim 5, wherein the recess pattern (298) comprises between two and ten holes.

9. A planet carrier (213) according to any preceding claim, wherein at least some of the recesses (298) of the recess pattern are axially non-opening.

10. A planet carrier (213) according to any preceding claim, wherein at least some of the recesses (298) of the recess pattern open out in the axial direction.

11. A planet carrier (213) according to any preceding claim, wherein at least some of the recesses (298) have a variable depth.

12. Planet carrier (213) according to one of the preceding claims, in which at least some of the recesses (298) are arranged symmetrically with respect to other identical recesses located on a second face (236b) axially opposite the first face (236a) of the disc (236) comprising these recesses (298).

13. Mechanical reducer (10) for an aircraft turbomachine, comprising a planet carrier (213) according to one of the preceding claims, the reducer further comprising: - a sun gear (11) which is centered on the central axis (X) and which is mounted between the discs (236, 238) of the planet carrier (213), - satellites (12) which are centered on the bearing axes (Y) and mounted between the discs (236, 238) of the planet carrier (213), the satellites (12) being guided in rotation by bearings (8) whose axial ends opposite are housed respectively in the first and second bearing holes (292, 294) of the discs (236, 238), and - a crown (14) centered on the central axis (X) and extending around the sun (11) and the satellites (12), the satellites (12) being meshed with the sun (11) and the crown (14).

14. Turbomachine (1), in particular for an aircraft, comprising a reducer (10) according to claim 13.

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