SATELLITE MOUNT FOR A MECHANICAL REDUCTION GEARBOX ON AN AIRCRAFT TURBOMACHINE

The planet carrier design with X-shaped bridges and radial slots and recesses addresses satellite misalignment issues in aircraft turbomachines, improving operational behavior and reducing material usage.

FR3162816B1Active Publication Date: 2026-05-22SAFRAN TRANSMISSION SYST
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Patent Information

Authority / Receiving Office
FR · FR
Patent Type
Patents
Current Assignee / Owner
SAFRAN TRANSMISSION SYST
Filing Date
2024-05-31
Publication Date
2026-05-22

AI Technical Summary

Technical Problem

Existing mechanical reducers in aircraft turbomachines face issues with planet carrier deformations leading to satellite misalignment and asymmetrical oil film formation or roller tilting, which degrade meshing and increase stress on gear teeth.

Method used

A planet carrier design with an annular cage connected by bridges having X-shaped bars and radial slots and recesses, providing flexibility and rigidity balance to prevent satellite misalignment.

Benefits of technology

The solution enhances the operational behavior of the satellite carrier by reducing misalignment and achieving a more flexible connection, while also minimizing material usage and assembly complexities.

✦ Generated by Eureka AI based on patent content.

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Patent Text Reader

Abstract

Planet carrier (13) for a mechanical gearbox (10) of an aircraft turbomachine (1), comprising an annular cage (26) including two disks (28, 30) connected at their outer periphery by brackets (32) each generally X-shaped and each comprising two intersecting bars (33, 34), the first disk (30) comprising an annular row of slots (50) formed at the outer periphery (30) of the first disk (30), and the bars (33, 34) of each of the brackets (32) defining between them a recess (40) which is closed axially on the side of the second disk (28) by the outer periphery (28b) of this second disk (28). Figure for the abbreviation: Figure 5
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Description

Title of the invention: SATELLITE MOUNT FOR A MECHANICAL REDUCTION GEARBOX OF AN AIRCRAFT TURBOMACHINE

[0001] The present invention relates to the field of mechanical reducers for turbomachinery, in particular aircraft. Technical background

[0002] The state of the art includes in particular the document EP-A1-3 055 589, EP-A1-3 732 384 and EP-A1-3 667 126.

[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 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 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 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] Satellite misalignment is an important point to monitor in order to avoid excessive stress on the gear teeth. To this end, the design of the satellite carrier can be optimized for flexibility to reduce or even eliminate this misalignment. In particular, it has already been proposed to integrate flexible zones into the carrier cage.

[0015] In the aforementioned documents EP-A1-3 732 384 and EP-A1-3 667 126, the Applicant proposed satellite carriers whose cages include particular designs and in particular bridges each having an X shape.

[0016] The present invention proposes an improvement which provides a simple, effective and economical solution to the aforementioned problem. Summary of the invention

[0017] The invention provides a planet carrier s for a mechanical gearbox of an aircraft turbomachine, the planet carrier s comprising a torque transmission element extending along an axis, and an annular cage extending around the axis and connected to a longitudinal end of the organ, said cage comprising two discs extending substantially radially with respect to the axis and connected at their outer periphery by bridges, a first of the discs having an inner periphery which is connected to said longitudinal end of the organ and an outer periphery which is connected by bridges to the outer periphery of a second of the discs, the first disc further having first orifices regularly distributed around the axis and aligned axially with second orifices of the second disc so as to form pairs of aligned orifices, each of the pairs having a first orifice and a second orifice aligned axially with the first orifice, the number of bridges being equal to the number of pairs of orifices and the bridges being intercalated in a circumferential direction between two pairs of adjacent orifices,each of the bridges having a general X shape and comprising two intersecting bars, the first ends of which are connected to the outer periphery of the first disc and the second ends of which are connected to the outer periphery of the second disc,

[0018] characterized in that the first disk comprises an annular row of lights which are formed at the outer periphery of the first disk, the number of lights being equal to the number of pairs of orifices, each of the lights being radially aligned with one of the first orifices of the first disk and opening radially outwards,

[0019] and in that the second ends of the bars of each of the bridges define between them a recess which is closed axially on the side of the second disk by the external periphery of this second disk.

[0020] The slots allow for greater flexibility in the first disc, which is the connecting disc between the cage and the transmission element, and thus for a more flexible connection between the cage and the transmission element. Conversely, the aforementioned recesses are closed on the side of the second disc, which makes this side of the cage more rigid. The combination of the two (slots and recesses) improves the behavior of the cage and the satellite carrier during operation, preventing or limiting satellite misalignment.

[0021] The solution proposed below is notably compatible: • of a simple or multi-stage reducer; • of an epicycloidal or differential reducer, where the planet carrier is rotationally mobile. • of straight or herringbone teeth.

[0022] The satellite carrier according to the invention may comprise one or more of the following features, taken individually or in combination with each other: - each of the lights has an elongated shape in a circumferential direction; - each of the lights has a circumferential length or dimension which is greater than the diameter of each of the first orifices; - each of the lights has a circumferential length or dimension which represents between 50 and 90% of a circumferential distance between two adjacent bridges, at the level of the first ends of their bars; - the opening of each of the lights is located on a circumference centered on the axis which has a diameter less than the external diameter of the cage measured at the level of the bridges; - each of the lights extends in a radial direction and has its radially internal end which opens onto the inner periphery of the first disk; - each of the lights has a width or axial dimension which represents between 20 and 60% of a width or axial dimension of the first disk; - each of the lights has an axial width or dimension which is greater than an axial width or dimension of each of the first orifices; - each of the lights has a general elliptical or oblong shape; - the recess of each of the bridges has a generally triangular shape or trapezoidal; - the outer periphery of the second disk defines the maximum external diameter of the cage and the satellite carrier; - the hollow of each of the bridges opens radially inside and outside the bridges; - the openings of the recesses, radially outwards, are located on a circumference centered on the axis, which has a diameter smaller than the external diameter of the second disk; - the diameter of said circumference represents 90% to 110% of the maximum diameter of another circumference centered on the axis and passing through the second orifices of the second disc; - the cage and the transmission element are formed from a single piece;

[0023] — the satellite carrier is capable of being mobile in rotation.

[0024] The present invention also relates to a mechanical gearbox for an aircraft turbomachine, comprising a planet carrier as described above, a sun gear centered on the axis and housed in the cage, a ring gear centered on the axis and mounted around the cage, and planet gears mounted in the cage and meshed with the sun gear and the ring gear, the planet gears being guided by bearings mounted in the first and second orifices of the cage. The gearbox is preferably of the epicyclic or differential type.

[0025] The present invention also relates to an aircraft turbomachine, comprising a reducer of the aforementioned type. Brief description of the figures

[0026] 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:

[0027] [Fig-1] [Fig.1] is a schematic axial cross-sectional view of a turbomachine using the invention;

[0028] [Fig.2] [Fig.2] is a schematic axial cross-sectional view of a mechanical reducer;

[0029] [Fig.3] [Fig.3] is a schematic perspective view of a mechanical reducer planet carrier;

[0030] [Fig.4] [Fig.4] is a schematic perspective view of another mechanical reducer planet carrier;

[0031] [Fig.5] [Fig.5] is a schematic perspective view of a mechanical reducer planet carrier, according to one embodiment of the invention;

[0032] [Fig. 6] [Fig. 6] is a larger-scale view of a detail of [Fig. 5]; and

[0033] [Fig.7] [Fig.7] is a larger scale view of another detail of [Fig.5]. Detailed description of the invention

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The gearbox 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 gearbox 10. This enclosure E is closed upstream by seals at level of a bearing allowing the passage of the blower shaft 4, and downstream by joints at the level of the passage of the BP shaft 3.

[0038] Figure 2 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 axis A of the turbomachine 1, drives a series of gears called planet gears 12, which are equally spaced circumferentially on the same diameter around the axis of rotation A. This diameter is equal to twice the operating center distance between the sun gear 11 and the planet gears 12. The number of planet gears 12 is generally defined between three and seven for this type of application.

[0039] The set of satellites 12 is held by a frame called a satellite carrier 13. Each satellite 12 rotates around its own Y axis, and meshes with the ring 14.

[0040] 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 axis A 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 13 is fixed to the fan shaft 4. • In a planetary configuration, the set of satellites 12 is held by a satellite carrier 13 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.

[0041] 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 axis A and parallel to this axis A. 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 13, and all these physical axes 13a are positioned relative to each other by means of one or more structural frames of the satellite carrier 13. 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 can be separated into several parts.

[0042] 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 gear teeth is located on the rim 14aa. of the reduction gear. This front helix meshes with that of satellite 12 which meshes with that of 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.

[0043] 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.

[0044] The arrows in [Fig. 2] 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.

[0045] Figures 3 and 4 show planet carriers 13 which are characterized by comprising a torque transmission element, also called a cage carrier, and an annular cage. These planet carriers 13 are described in documents EP-A1-3 732 384 and EP-A1-3 667 126.

[0046] The satellite carrier 13 extends along the axis A and comprises two parts: a torque transmission element 24 with longitudinal axis A and an annular cage 26 extending around the axis A.

[0047] The annular cage 26 is connected to a longitudinal end of the member 24. The member 24 is tubular and extends axially (along axis A). It has a generally cylindrical or frustoconical shape, one longitudinal end of which is extended by an annular connecting portion designed to connect with the turbine shaft 14 (see [Fig. 1]). Thus, the front longitudinal end of the member 24 is connected to the cage 26, and the rear end, which has splines, is designed to mesh with the turbine shaft 14.

[0048] The front is defined as being on the side of the blower and the rear is defined as being on the side of the exhaust nozzle of the turbomachine.

[0049] The annular cage 26 comprises two discs 28, 30 extending substantially radially with respect to the axis A, respectively a front disc or first disc 28 and a rear disc or second disc 30.

[0050] The front disc 28 is defined as the disc attached to the component 24, and the second disc 30 is defined as the one located on the opposite side of the transmission component 24.

[0051] The two discs 28, 30 are connected to each other by bridges 32. As illustrated in figures 3 and 4, each bridge 32 comprises two intersecting arms or bars 33, 34 and therefore has a general X shape. Each bar 33, 34 is thus divided into two corresponding parts substantially aligned and extending on either side of the intersection (or crossing zone) of the X.

[0052] In the figures, the two corresponding bars 33, 34 of each bridge 32 intersect in an area located near one of the discs 28, 30, or halfway between the discs.

[0053] The planet carrier 13 is formed here as a single piece. This means that the cage 26 and the component 24 are formed as a single piece, but also that the discs 28, 30 and the bridges 32 are formed as a single piece. This allows the planet carrier 13 to form a single structural assembly, effectively eliminating the problems associated with assembling several parts using additional connecting elements. In particular, this avoids problems related to imbalance generated by assembly tolerances, mounting problems, or the additional mass due to the multiplication of parts.

[0054] The discs 28, 30 each have orifices 36 each used for mounting one end of a satellite shaft 20 ([Fig.2]) and thus forming seats for the satellites 20. These orifices 36 are intended to receive bearings (not shown) for guiding the satellites 12.

[0055] The disc 28 includes, between two adjacent orifices 36, at least one or two notches 38, 39. In the example shown, the notches are aligned with a bridge 32 along a plane passing through the X axis.

[0056] Each notch 38 is located on the outer periphery of the disc 28, between the corresponding bars 33, 34 of each bridge 32, and has a general U or V shape with its opening oriented radially outwards with respect to the X axis. Each notch 39 is located on the inner periphery of the flank 28 and has a general U or V shape. These notches 38, 39 are arranged head to tail so that their points or bottoms are oriented towards each other.

[0057] During operation of the reduction gear train 10, a first force path passes through the disc 30 (from the corresponding ends of the orifices 36 of the satellites 12) and then through the torque transmission element 24. A second force path passes through the disc 28 (from the corresponding ends of the orifices 36 of the satellites 12) to the areas of connection between the front disc 28 and the bridges 32, the bridges 32 then the torque transmission element 24.

[0058] The cage 26, which supports the bearings and therefore the satellites 12, is thus formed with the bars 33, 34 interlaced to obtain "lattices" or "crossbars". This allows the forces necessary for the operation of the reducer 10 to be transmitted effectively with a minimum of material.

[0059] It can also be seen in figures 3 and 4 that the intersecting bars 33, 34 of each bridge 32 delimit at their ends connected to the disc 28 a recess 40 which is axially open and therefore opens axially on the opposite side to the other disc 30. Each of these recesses 40 communicates with one of the aforementioned notches 38.

[0060] The present invention proposes an improvement to existing technologies, one embodiment of which is shown in figures 5 to 7.

[0061] The invention relates to a satellite carrier 13 for a mechanical gearbox of an aircraft turbomachine. The preceding description made in relation to the turbomachine of [Fig. 1] and the gearbox 10 of [Fig. 2] can be used to describe the invention. Furthermore, the preceding description made in relation to Figures 3 and 4 can also be used to describe the invention insofar as it does not contradict or inconsistent with what follows.

[0062] The satellite carrier 13 includes a torque transmission member 24 extending along an axis X, and an annular cage 26 extending around the axis X and connected to a longitudinal end 24a of the member 24.

[0063] The cage 26 comprises two discs 28, 30 extending substantially radially with respect to the X axis and connected at their outer periphery by bridges 32.

[0064] A first of the discs 30 extends radially with respect to the axis X and has an inner periphery 30a which is connected to the aforementioned longitudinal end 24a of the organ 24, and an outer periphery 30b which is connected by bridges 32 to the outer periphery 28b of the second disc 28. The second disc 28 includes an inner periphery 28a.

[0065] The disk 30 has first orifices 36a regularly distributed around the X axis and aligned axially with second orifices 36b of the disk 28 so as to form pairs of aligned orifices 36a, 36b.

[0066] Each of the pairs 36a, 36b comprises a first orifice 36a and a second orifice 36b aligned axially with the first orifice 36a.

[0067] The number of bridges 32 is equal to the number of pairs of orifices 36a, 36b and the bridges 32 are intercalated in a circumferential direction between two pairs of adjacent orifices 36a, 36b.

[0068] Each of the bridges 32 has a general X shape and comprises two intersecting bars 33, 34, the first ends of which 33a, 34a are connected to the periphery external of disk 30, and whose second ends 33b, 34b are connected to the external periphery of disk 28.

[0069] According to the invention, the disc 30 comprises an annular row of lights 50 which are formed at the outer periphery of the disc 30.

[0070] The number of lights 50 is equal to the number of pairs of orifices 36a, 36b, which is five in the example shown.

[0071] Each of the lights 50 is radially aligned with one of the first orifices 36a of the disk 30 and opens radially outwards.

[0072] Each of the lights 50 preferably has an elongated shape in the circumferential direction.

[0073] Each of the lights 50 can have a circumferential length or dimension L1 which is greater than the diameter DI of each of the first orifices 36a ([Fig.7]).

[0074] This length L1 can represent between 50 and 90% of a circumferential distance H1 between two adjacent bridges 32, at the level of the first ends 33a, 34a of the bars 33, 34 ([Fig.7]).

[0075] The outlet of each of the lights 50 can be located on a circumference centered on the axis X which has a diameter D2 less than the external diameter D3 of the cage 26 measured at the level of the bridges 32 ([Fig.6]).

[0076] Each of the lights 50 extends in a radial direction and preferably has its radially internal end opening onto the inner periphery of the disk 30.

[0077] Each of the lights 50 can have a width L2 or axial dimension which represents between 20 and 60% of a width L3 or axial dimension of the disk 30 ([Fig.7]).

[0078] This width L2 can be greater than a width L4 or axial dimension of each of the orifices 36a ([Fig.7]).

[0079] Each of the lights 50 preferably has a general elliptical or oblong shape.

[0080] Another particularity of the invention relates to the second ends 33b, 34b of the bars 33, 34 of each of the bridges 32 which define between them a recess 40 which is closed axially on the side of the disc 28 by the external periphery of this disc 28.

[0081] The recess 40 of each of the bridges 32 preferably has a general triangular or trapezoidal shape.

[0082] Advantageously, the outer periphery of the disk 28 defines the maximum outer diameter D4 of the cage 26 and of the satellite carrier 13 ([Fig.6]).

[0083] The recess 40 of each of the bridges 32 preferably opens radially into the inside and outside of the bridges 32, and is therefore through in the radial direction.

[0084] The outlets of the recesses 40, radially outwards, are preferably located on a circumference centered on the axis A, which has a diameter D6 less than the external diameter D4 of the disk 28 ([Fig.6]).

[0085] The diameter D6 of this circumference preferably represents 90% to 110% of the maximum diameter D5 of another circumference centered on the axis A and passing through the orifices 36b of the disk 28. This means that the outlets of the recesses 40 are located on a diameter close to that of the radially external ends of the orifices 36b of the disk 28 ([Fig.6]).

[0086] The combination of the slots 50 and the recesses 40 as described above makes it possible to greatly reduce the misalignment seen by the satellites, by balancing the stiffness between the two sides of the satellite carrier cage. Furthermore, a mass reduction is also achieved through these material removals.

Claims

1. Demands A satellite carrier (13) for a mechanical gearbox (10) of an aircraft turbomachine (1), the satellite carrier (13) comprising a torque transmission element (24) extending along an axis (X), and an annular cage (26) extending around the axis (X) and connected to a longitudinal end (24a) of the element (24), said cage (26) comprising two disks (28, 30) extending radially with respect to the axis (X) and connected at their outer periphery by bridges (32), a first of the disks (30) comprising an inner periphery (30a) which is connected to said longitudinal end (24a) of the element (24) and an outer periphery (30b) which is connected by bridges (32) to the outer periphery (28b) of a second of the disks (28), the first disk (30) further comprising the first orifices (36a) regularly distributed around the axis (X) and aligned axially with second orifices (36b) of the second disk (28) so as to form pairs of aligned orifices (36a, 36b),Each of the pairs (36a, 36b) comprising a first orifice (36a) and a second orifice (36b) axially aligned with the first orifice (36a), the number of bridges (32) being equal to the number of pairs of orifices (36a, 36b), and the bridges (32) being interposed circumferentially between two pairs of adjacent orifices (36a, 36b), each of the bridges (32) having a general X shape and comprising two intersecting bars (33, 34) whose first ends (33a, 34a) are connected to the outer periphery (30b) of the first disk (30) and whose second ends (33b, 34b) are connected to the outer periphery (28b) of the second disk (28), characterized in that the first disk (30) comprises an annular row of lights (50) which are formed at the outer periphery (30) of the first disk (30), the number of lights (50) being equal to the number of pairs of orifices (36a, 36b),each of the lights (50) being radially aligned with one of the first orifices (36a) of the first disk (30) and opening radially outwards, and in that the second ends (33b, 34b) of the bars (33, 34) of each of the bridges (32) define between them a recess (40) which is closed axially on the side of the second disk (28) by the outer periphery (28b) of this second disk (28).

2. Satellite carrier (13) according to claim 1, wherein each of the lights (50) has an elongated shape in the circumferential direction.

3. Satellite carrier (13) according to claim 1 or 2, wherein each of the lights (50) has a length (Ll) or circumferential dimension which is greater than the diameter (Dl) of each of the first orifices (36a).

4. Satellite carrier (13) according to any one of the preceding claims, wherein each of the lights (50) has a length (Ll) or circumferential dimension which represents between 50 and 90% of a circumferential distance (Hl) between two adjacent bridges (32), at the first ends (33a, 34a) of their bars (33, 34).

5. Satellite carrier (13) according to any one of the preceding claims, wherein the opening of each of the lights (50) is located on a circumference centered on the axis (X) which has a diameter (D2) less than the external diameter (D3) of the cage (26) measured at the level of the bridges (32).

6. Satellite carrier (13) according to any one of the preceding claims, wherein each of the lights (50) extends in a radial direction and has its radially internal end opening onto the inner periphery of the first disk (30).

7. Satellite carrier (13) according to any one of the preceding claims, wherein each of the lights (50) has a width (L2) or axial dimension which represents between 20 and 60% of a width (L3) or axial dimension of the first disk (30).

8. Satellite carrier (13) according to any one of the preceding claims, wherein each of the lights (50) has a width (L2) or axial dimension that is greater than a width (L4) or axial dimension of each of the first orifices (36a).

9. Satellite carrier (13) according to any one of the preceding claims, wherein each of the lights (50) has a general elliptical or oblong shape.

10. Satellite carrier (13) according to any one of the preceding claims, wherein the recess (40) of each of the bridges (32) has a general triangular or trapezoidal shape.

11. Satellite carrier (13) according to any one of the preceding claims, wherein the outer periphery (28b) of the second disk (28) defines the maximum outer diameter (D4) of the cage (26) and of the satellite carrier (13).

12. Satellite carrier (13) according to any one of the preceding claims, wherein the recess (40) of each of the bridges (32) opens radially into and out of the bridges (32).

13. Satellite carrier (13) according to claim 12, wherein the outlets of the recesses (40), radially outwards, are located on a circumference centered on the axis, which has a diameter (D6) less than the external diameter (D4) of the second disk (28).

14. Satellite carrier (13) according to claim 12 or 13, wherein the diameter (D6) of said circumference represents 90% to 110% of the maximum diameter (D5) of another circumference centered on the axis (X) and passing through the second orifices (36b) of the second disk (28).

15. Satellite carrier (13) according to any one of the preceding claims, wherein the cage (26) and the transmission member (24) are formed in one piece.

16. Mechanical reducer (10) for an aircraft turbomachine (1), comprising a satellite carrier (13) according to any one of the preceding claims, a sun (7) centered on the axis (X) and housed in the cage (26), a ring (14) centered on the axis (X) and mounted around the cage (26), and satellites (12) mounted in the cage and meshed with the sun (7) and the ring (14), the satellites (12) being guided by bearings mounted in the first and second orifices (36a, 36b) of the cage (26).

17. Aircraft turbomachine (1), comprising a reduction gear (10) according to the preceding claim.