SATELLITE MOUNT FOR A MECHANICAL REDUCTION GEARBOX ON AN AIRCRAFT TURBOMACHINE

The satellite carrier with annular grooves in the disk addresses force transmission issues in turbomachinery gearboxes, ensuring balanced force distribution and preventing gear misalignment, thus improving operational stability.

FR3163979B1Active 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
2024-06-28
Publication Date
2026-05-22

AI Technical Summary

Technical Problem

Existing mechanical reducers for turbomachinery, particularly in aircraft, face issues with the transmission of forces during operation, leading to potential misalignment of planet gears due to the complex geometry of the planet carrier, which is constrained by limited space.

Method used

A satellite carrier with a monobloc cage design featuring annular grooves around orifices in the disk, allowing for continuous extension and reduced material thickness, ensuring balanced force distribution without generating moments in the epicyclic or planetary gear train.

Benefits of technology

The solution provides improved force centrality and flexibility, preventing gear misalignment while being compatible with various reducer types and tooth configurations, enhancing operational stability.

✦ Generated by Eureka AI based on patent content.

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Abstract

Planet carrier (110) for a mechanical gearbox (6) of a turbomachine (1), comprising a cage (114) formed in one piece and having two disks (114a, 114b) connected to each other by bridges (116), the first of the disks (114a) having first orifices (124a) and annular grooves (128) around the first orifices (124a), each annular groove (128) extending around a ring of material (130) which has an axial dimension (L1) less than a maximum axial depth (Q1) of the groove (128), and a constant thickness (E1) or radial dimension along this internal cylindrical surface (125). Abbreviated figure: Figure 6
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Description

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

[0001] The present invention relates to the field of mechanical reducers for turbomachinery, in particular aircraft, and in particular reducers equipped with double-stage gearing satellites. Technical background

[0002] The state of the art includes in particular documents WO-A1-2010 / 092263, FR-A1-2 987 416, FR-A1-3 011 901, FR-A1-3 041 054 and FR-Al-3 058 493.

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

[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 X 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 planetary gears. These axes are parallel to the longitudinal axis X.

[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 gearbox, the planet carrier is fixed and the ring gear 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 fields.

[0011] In this application, the term "stage" or "toothing" refers to a series of teeth interlocking with a series of complementary teeth. A toothing can be internal or external.

[0012] A satellite may comprise one or two gear stages. A single-stage satellite comprises teeth that may be straight, helical, or chevron-shaped, and whose teeth are located on the same diameter. These teeth cooperate with both the sun gear and the crown gear.

[0013] A two-stage satellite comprises two sets of teeth or two series of teeth which are located on different diameters. A first set of teeth cooperates with the sun gear and a second set of teeth cooperates with the crown gear.

[0014] There are two satellite carrier technologies, monobloc satellite carriers and satellite carriers which comprise a cage and a cage carrier connected together by flexible links.

[0015] The present invention relates to monobloc type satellite carriers. A satellite carrier of this type comprises a cage formed in one piece with a portion of shaft.

[0016] The cage comprises two annular discs connected together by bridges, these bridges defining satellite reception housings between themselves and with the discs. The discs have mounting holes for the axial ends of the satellite guidance bearings. These holes are commonly called "reception holes".

[0017] One of the problems with a gearbox of this type concerns the transmission of forces during operation and the risk of misalignment of the planet gears. Indeed, in a one-piece planet carrier, the forces applied to the planet gears are transmitted by the bearings to the planet carrier discs. The configuration of the planet carrier does not allow for the centered distribution of these forces due to the presence of the ring gear. Therefore, the balancing of forces must be achieved through the geometry of the planet carrier. However, the planet carrier is a complex component with limited space available to accommodate this specific geometry.

[0018] The Applicant has already proposed in document FR-A1-3 136 533 to make modifications in the form of annular grooves around the openings of one of the cage's discs. Each groove makes it possible to reduce the thickness of the disc locally, around each of its openings, so as to increase its flexibility (or reduce its stiffness).

[0019] The invention proposes an improvement to this technology, which is simple, efficient and economical. Summary of the invention

[0020] The invention relates to a satellite carrier for a mechanical turbomachine gearbox, in particular for aircraft, this satellite carrier having a main axis and comprising a cage formed in one piece and comprising two discs extending around the axis and connected to each other by bridges which are distributed around the axis, a first of the discs having first orifices which are distributed around the axis and which are axially aligned with second orifices of a second of the discs, each of the first and second orifices having an internal cylindrical surface, and said first disc having an annular groove around each of its first orifices, each annular groove extending continuously all around the corresponding first orifice and opening in an axial direction,

[0021] characterized in that each annular groove extends around a ring of material which includes at its inner periphery the internal cylindrical surface of the first corresponding orifice, this internal cylindrical surface having an axial dimension less than a maximum axial depth of the groove, and each ring of material having a constant thickness or radial dimension along this internal cylindrical surface and being connected to the rest of the first disk by a veil of material which has a minimum thickness less than this thickness.

[0022] The aim of this invention is to propose a solution for a monobloc cage satellite carrier that does not generate any moment in the satellites when operating with an epicyclic or planetary gear train.

[0023] This invention is notably compatible with: - of a single stage or double stage reducer; - of a planetary, epicycloidal or differential reducer; - a one-piece satellite carrier; - of any type of toothing (straight, helical or herringbone); - hydrodynamic bearings and / or rolling elements.

[0024] 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 first disc comprises a first radial annular face onto which each groove opens, each ring having a first longitudinal end which is aligned in a radial direction with this first annular face; - the first disk comprises a second radial annular face, opposite said first radial annular face, each ring comprising a second longitudinal end, opposite to said first longitudinal end, which is axially recessed with respect to this second annular face; - the axial dimension of each ring of material represents between 50 and 90%, and preferably between 40 and 80%, of an axial dimension of the disk measured between its first and second radial annular faces; - each layer of material is located radially between a bottom of the corresponding groove and a cylindrical bore of the first disc which is centered on the first corresponding orifice and which opens onto said second radial annular face; - each cylindrical bore has a constant diameter which is greater than a diameter of the internal cylindrical surface and which is less than a minimum diameter of the throat; - each bore has an axial dimension which represents between 10 and 50%, and preferably between 20 and 40%, of an axial dimension of the disc measured between its first and second radial annular faces; - the satellite carrier further includes a portion of a shaft which is centered on the central axis and whose longitudinal end is connected to said first annular face; - each throat opens into the cage; - each groove opens on the opposite side to the portion of the tree;

[0025] — each of the first orifices is surrounded by a single groove;

[0026] — the number of grooves in the first disc is equal to the number of first orifices in this first album;

[0027] — the axial dimension of each ring of material is less than one dimension axial of the disc at the level of which the groove is formed; - the throat is delimited by two cylindrical walls, respectively internal and external, which face each other and are connected together by a concave curved annular wall; - the thickness of the ring of material is less than a width or radial dimension of the corresponding groove.

[0028] The present invention further relates to a mechanical reducer for an aircraft turbomachine, this reducer comprising a satellite carrier according to one of the preceding claims, satellites which are guided by bearings whose axial ends are engaged in said first and second orifices, and in particular on the internal cylindrical surfaces of these first and second orifices, and a solar element which is housed in the cage and which is meshed with the satellites.

[0029] The present invention further relates to an aircraft turbomachine comprising a satellite carrier or a reduction gear as described above. Brief description of the figures

[0030] 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:

[0031] [Fig-1] [Fig.1] is a schematic axial cross-sectional view of a turbomachine aircraft,

[0032] [Fig.2] [Fig.2] is a partial axial view of a mechanical reducer,

[0033] [Fig.3] [Fig.3] is an axial cross-sectional view of a mechanical reducer equipped with double-stage meshing satellites, and illustrates the prior art to the invention,

[0034] [Fig.4] [Fig.4] is a perspective view of the satellite carrier of the reducer [Fig.3],

[0035] [Fig. 5] [Fig. 5] is a partial axial view of a satellite carrier and a mechanical reducer of the prior art,

[0036] [Fig.6] [Fig.6] is a perspective view of a satellite carrier according to a mode of realization of the invention,

[0037] [Fig.7] [Fig.7] is a perspective and axial cross-sectional view of the satellite carrier of the [Fig.7], on a larger scale, and

[0038] [Fig.8] [Fig.8] is another perspective and axial sectional view of the carrier satellites of the [Fig.7], on a larger scale. Detailed description of the invention

[0039] Figure 1 describes a turbomachine 1 which conventionally comprises a rotation shaft X, 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) unit. 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) unit.

[0040] The blower S is driven by a blower shaft 4 which is driven to the BP shaft 3 by means of a reducer 6. This reducer 6 is generally of the planetary or epicycloidal type.

[0041] The following description relates to a planetary type reducer in which the ring is mobile in rotation.

[0042] The gearbox 6 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 6. This enclosure E is closed upstream by seals. at the 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.

[0043] Figure 2 shows a gearbox 6 which can take the form of different architectures depending on whether certain parts are fixed or rotating. At the input, the gearbox 6 is connected to the shaft BP 3, for example via internal splines 7a. Thus, the shaft BP 3 drives a planetary gear called the sun gear 7. Conventionally, the sun gear 7, whose axis of rotation coincides with that of the turbomachine X, drives a series of gears called planet gears 8, which are equally spaced on the same diameter around the axis of rotation X. This diameter is equal to twice the operating center distance between the sun gear 7 and the planet gears 8. The number of planet gears 8 is generally defined between three and seven for this type of application.

[0044] The set of satellites 8 is held by a frame called a satellite carrier 10. Each satellite 8 rotates around its own Y axis, and meshes with the ring 9. • In this planetary configuration, the set of satellites 8 is held by a satellite carrier 10 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 12.

[0045] Each satellite 8 is mounted to rotate freely by means of a bearing 11, for example, a roller bearing or hydrodynamic bearing. Each bearing 11 is mounted on one of the axes 10b of the satellite carrier 10, and all the axes are positioned relative to each other by means of one or more structural frames 10a of the satellite carrier 10. There is a number of axes 10b and bearings 11 equal to the number of satellites. For reasons of operation, assembly, manufacturing, inspection, repair, or replacement, the axes 10b and the frame 10a may be separated into several parts.

[0046] For the same reasons mentioned above, the teeth of a gearbox can be separated into several helices, each having a median plane P. In the example shown, the ring gear is separated into two half-ring gears: • An upstream half-crown 9a consisting of a rim 9aa and a mounting half-flange 9ab. The upstream helix of the reduction gear teeth is located on the rim 9aa. This upstream helix meshes with that of the satellite 8, which in turn meshes with that of the solar 7. • A downstream half-crown 9b consisting of a rim 9ba and a mounting flange half 9bb. The downstream helix of the reduction gear teeth is located on the rim 9ba. This downstream helix meshes with that of the satellite 8, which in turn meshes with that of the solar 7.

[0047] The mounting half-flange 9ab of the upstream crown 9a and the mounting half-flange 9bb of the downstream crown 9b form the mounting flange 9c of the crown. The crown 9 is fixed to a crown carrier by assembling the mounting flange 9c of the crown and the 12a mounting flange of the crown carrier using a bolted mounting for example.

[0048] The arrows in [Fig. 2] describe the oil flow in the gearbox 6. The oil enters the gearbox 6 from the stator section 5 via a distributor 13 by various means, which will not be specified in this view as they are specific to one or more types of architecture. The distributor is generally divided into two parts, each repeated with the same number of planetary gears. The injectors 13a lubricate the gear teeth, and the arms 13b lubricate the bearings. The oil is supplied to the injector 13a and exits through the end 13c to lubricate the gear teeth. The oil is also supplied to the arm 13b and circulates through the bearing's oil inlet 13d. The oil then flows through the shaft into one or more buffer zones 10c and then exits through the orifices lOd to ​​lubricate the satellite bearings.

[0049] Figures 3 and 4 represent a turbomachine gearbox 6 of an aircraft according to the prior art.

[0050] The reducer 6 includes a planet carrier s 10 which is configured to be mobile in rotation around the X axis and which is of the monobloc type, i.e. formed of a single piece.

[0051] This satellite carrier 10 includes a cage 14 and a portion of a shaft 15.

[0052] The shaft portion 15 has a generally tubular shape and is elongated along the axis X and includes a free longitudinal end, here on the left in the drawings, and an opposite longitudinal end for connection to cage 14.

[0053] The shaft portion 15 includes an external gear 15a for meshing, for example with a blower.

[0054] The cage 14 comprises two annular disks 14a, 14b which are parallel and spaced apart from each other and extend perpendicularly to the X axis. The disks 14a, 14b have a general circular shape and are centered on the X axis.

[0055] The disk 14a, called the first disk, on the left in the drawing, is connected to the portion of the shaft 15. The other disk 14b is called the second disk.

[0056] The disks 14a, 14b are connected to each other by bridges 16 which define between themselves and with the disks housings 18 configured to receive the satellites 8. The housings 18 open radially outwards at the outer periphery of the cage 14, and also open radially inwards by passing through an internal tubular wall 20 of the cage 14. The bridges 16 can be solid or partially hollow.

[0057] The wall 20 extends around the X axis, from the first disk 14a towards the second disk 14b. Here it extends substantially in the axial continuation of the portion of the shaft 15. This wall 20 internally delimits a space 22 for housing the solar element 7.

[0058] This space 22 comprises two adjacent parts. The first part 22a is surrounded by the wall 20 which includes an internal cylindrical surface 22a for mounting a bearing 23 for guiding one end of the solar element 7. The second part 22b, located at the openings of the housings 18, receives the opposite end of the solar element 7, which includes an external toothed section 7b for meshing with the satellites 8. The solar element 7 further includes an internal toothed section 7a for coupling to a shaft, for example, of a turbine.

[0059] The housings 18 each comprise a first part 18a which is located on the side of the first disc 14a, and a second part 18b which is located on the side of the second disc 14b. The housings 18 open onto the outer periphery of the shaft 14, at the level of its two parts 18a, 18b, and onto the inner periphery of the shaft 14, at the level of the second parts 18b only.

[0060] The discs 14a, 14b include aligned mounting holes 24 for the satellites 8 and in particular for the plain bearings 26 of these satellites 8. Each bearing 26 has a general cylindrical shape which extends parallel to the X axis and whose longitudinal ends include extensions 26a housed in the holes 24 forming seats.

[0061] In a known manner, each bearing 26 can include an internal oil circulation bore 26b which generally communicates with oil supply channels to the external cylindrical surface 26c of the bearing for the purpose of forming an oil film on this surface 26c.

[0062] The satellites 8 are here of the double-stage meshing type and each comprise a tubular body 8a equipped with a first external toothing 28 and connected by a veil 30 to a second external toothing 32.

[0063] The teeth 28, 32 are arranged next to each other and more particularly are located respectively in two planes perpendicular to the X axis.

[0064] The first tooth 28, located on the left in the drawings, is situated on the side of the first disc 14a and therefore at the level of the first part 18a of the housing. As can be seen in [Fig. 3], this tooth 28 meshes with the ring 9.

[0065] The second toothing 32, located on the right in the drawings, is situated on the side of the second disk 14b and therefore at the level of the second part 18b of the housing. As can be seen in [Fig. 3], this toothing 32 meshes with the toothing 7b of the solar 7.

[0066] As can be seen in [Fig.3], the bridges 16 extend radially, between the housings 18, from the wall 20 and the inner periphery of the discs 14a, 14b to the outer periphery of the discs.

[0067] In this type of planet carrier, it is important to ensure that the forces are transferred during operation between the turbine and the planet carrier. The forces first pass through the shaft portion 15 and then reach the upstream disc 14a. They then pass via the upstream disk 14a to pass through the bearings 26 and the satellites 8. This transmission of forces via one of the disks risks causing a tilting of the satellites 8 and therefore misalignments between their teeth 28, 32 and those of the solar 7 and the crown 9.

[0068] The Applicant has already proposed a solution to this problem which is illustrated in [Fig.5] and described in the aforementioned document.

[0069] The satellite carrier 110 comprises a cage 114 which has two annular disks 114a, 114b which are parallel and spaced apart from each other and extend perpendicularly to the X axis. The disks 114a, 114b have a general circular shape and are centered on the X axis.

[0070] The disk 114a, called the first disk, on the right in the drawing, is connected to a portion of the shaft 115. The other disk 114b is called the second disk.

[0071] The disks 114a, 114b are connected to each other by bridges 116 which define between each other and with the disks housings 118 configured to receive the satellites 8.

[0072] The disks 114a, 114b include aligned mounting ports 124a, 124b for the satellites 8 and in particular for the guidance bearings of these satellites 8. The ports 124a of the first disk 114a are called first ports, and the ports 124b of the second disk 114b are called second ports.

[0073] As can be seen in [Fig.5], the first disc 114a has groove-type thinnings 128 around each of the first orifices 124a.

[0074] The present invention proposes an improvement to this technology.

[0075] Figures 6 to 8 illustrate an embodiment of a satellite carrier according to the invention.

[0076] The following description relates to the characteristics of the planet carrier according to the invention. This planet carrier is intended to be mounted in a mechanical gearbox of the aforementioned type, which will not be described in detail hereafter. The preceding description, made in conjunction with Figures 1 to 4, can thus be used to describe a gearbox comprising a planet carrier according to the invention.

[0077] The satellite carrier 110 of figures 6 to 8 comprises a cage 114 and a shaft portion 115. The cage 114 is formed in one piece and can also be formed in one piece with the shaft portion 115.

[0078] The shaft portion 115 has a general tubular shape and is elongated along the X axis and includes a free longitudinal end, here on the right in the drawings, and an opposite longitudinal end for connection to the cage 114.

[0079] The shaft portion 115 may include an external meshing toothing, for example with a blower shaft.

[0080] The cage 114 comprises two annular disks 114a, 114b which are parallel and spaced apart from each other and extend perpendicularly to the X axis. The disks 114a, 114b have a general circular shape and are centered on the X axis.

[0081] The disk 114a, called the first disk, on the right in [Fig.6], is connected to the portion of shaft 115. The other disk 114b is called the second disk.

[0082] The disks 114a, 114b are connected to each other by bridges 116 which define, between themselves and with the disks, housings 118 configured to receive the satellites. The housings 118 open radially outwards at the outer periphery of the cage 114, and also open radially inwards.

[0083] The bridges 116 are preferably solid and are as straight and rigid as possible within the framework of the present invention.

[0084] The discs 114a, 114b include aligned mounting ports 124a, 124b for the satellites and, in particular, for the guiding bearings of these satellites. Each bearing may have a generally cylindrical shape extending parallel to the X-axis and whose longitudinal ends include extensions housed in the ports 124a, 124b, forming seats or recesses. The ports 124a of the first disc 14a are called the first ports, and the ports 124b of the second disc 14b are called the second ports. As is known, each satellite bearing may include an internal oil circulation bore as described above.

[0085] Each of the orifices 124a, 124b has an internal cylindrical surface 125, 126. The internal cylindrical surfaces 126 of the orifices 124b may have an axial dimension identical to that of the second disk 124b.

[0086] The first disc 114a has an annular groove 128 around each of its first orifices 124a.

[0087] Each annular groove 128 extends continuously all around the corresponding first orifice 124a and opens in an axial direction ([Fig.7]), preferably inside the cage 114, i.e. in the direction of the second disc 114b.

[0088] According to the invention, each annular groove 128 extends around a ring of material 130, which is more clearly visible in figures 7 and 8, and which includes at its inner periphery the internal cylindrical surface 125 of the corresponding first orifice 124a.

[0089] This internal cylindrical surface 125 has an axial dimension L1 less than a maximum axial depth Q1 of the groove 128 ([Fig.7]).

[0090] The groove 128 is preferably delimited by two cylindrical walls, respectively internal 128a and external 128b, which face each other and which are connected together by a concave curved annular wall 128c.

[0091] Each ring of material 130 has a constant thickness El or radial dimension along this internal cylindrical surface 125 and is connected to the rest of the first disk 114a by a veil of material 132 which has a minimum thickness E2 less than this thickness El ([Fig.7]).

[0092] The thickness El of the ring of material 130 is preferably less than a width E3 or radial dimension of the corresponding groove 128 ([Fig.7]).

[0093] The first disc 114a preferably includes a first radial annular face 134 on which the grooves 128 open. Each ring 130 may include a first longitudinal end 130a which is aligned in a radial direction with this first annular face 134.

[0094] The first disc 114b preferably includes a second radial annular face 136, opposite the first radial annular face 134. Each ring 130 may include a second longitudinal end 130b, opposite the first longitudinal end 130a, which is axially recessed with respect to this second annular face 136.

[0095] Preferably, the axial dimension L1 of each ring of material 130 is less than an axial dimension L2 of the disk 114a at the level of which the groove 128 is formed ([Fig.7]).

[0096] The axial dimension L1 of each ring of material 130 can represent between 50 and 90%, and preferably between 40 and 80%, of the axial dimension L2 of the disk measured between its first and second radial annular faces 134, 136 ([Fig.7]).

[0097] Each material veil 132 is preferably located radially between a bottom of the corresponding groove 128 and a cylindrical bore 138 of the first disc 114a which communicates with the orifice 124a and which opens onto the second radial annular face 136.

[0098] Each cylindrical bore 138 preferably has a constant diameter D2 which is greater than a diameter DI of the internal cylindrical surface 125 and which is less than a minimum diameter D3 of the groove ([Fig.7]).

[0099] Each bore 138 can have an axial dimension L3 which represents between 10 and 50%, and preferably between 20 and 40%, of the axial dimension L2 of the disk 114a measured between its first and second radial annular faces 134, 136 ([Fig.7]).

[0100] The invention offers several advantages, including: - an easy solution to implement in a confined space; - measurable and configurable gain in flexibility; - improved centrality of forces on a monobloc satellite carrier.

Claims

Demands

1. A planet carrier (110) for a mechanical gearbox (6) of a turbomachine (1), in particular of an aircraft, said planet carrier (110) having a main axis (X) and comprising a cage (114) formed in one piece and comprising two disks (114a, 114b) extending around the axis (X) and connected to each other by bridges (116) which are distributed around the axis (X), a first of the disks (114a) having first orifices (124a) which are distributed around the axis (X) and which are axially aligned with second orifices (124b) of a second of the disks (114b), each of the first and second orifices (124a, 124b) having an internal cylindrical surface (125, 126), and said first disk (114a) having an annular groove (128) around each of its first orifices (124a), each annular groove (128) extending continuously all around the corresponding first orifice (124a) and opening in an axial direction,characterized in that each annular groove (128) extends around a ring of material (130) which includes at its inner periphery the internal cylindrical surface (125) of the corresponding first orifice (124a), this internal cylindrical surface (125) having an axial dimension (L1) less than a maximum axial depth (Q1) of the groove (128), and each ring of material (130) having a constant thickness (E1) or radial dimension along this internal cylindrical surface (125) and being connected to the rest of the first disk (114a) by a veil of material (132) which has a minimum thickness (E2) less than this thickness (E1).

2. Satellite carrier (110) according to claim 1, wherein the first disc (114a) comprises a first radial annular face (134) into which each groove (128) opens, each ring (130) having a first longitudinal end (130a) which is aligned in a radial direction with this first annular face (134).

3. Satellite carrier (110) according to claim 2, wherein the first disc (114a) comprises a second radial annular face (136), opposite said first radial annular face (134), each ring (130) comprising a second longitudinal end (130b), opposite said first longitudinal end (130a), which is axially recessed with respect to this second annular face (136).

4. Satellite carrier (110) according to claim 3, wherein the axial dimension (L1) of each ring of material (130) represents between 50 and 90%, and preferably between 40 and 80%, of an axial dimension (L2) of the disk (114a) measured between its first and second radial annular faces (134, 136).

5. Satellite carrier (110) according to claim 3 or 4, wherein each web of material (132) is located radially between a bottom of the corresponding groove (128) and a cylindrical bore (138) of the first disc (114a) which is centered on the corresponding first orifice (124a) and which opens onto said second radial annular face (136).

6. Planet carrier (110) according to claim 5, wherein each cylindrical bore (138) has a constant diameter (D2) which is greater than a diameter (Dl) of the internal cylindrical surface (125) and which is less than a minimum diameter (D3) of the groove (128).

7. Satellite carrier (110) according to claim 5 or 6, wherein each bore (138) has an axial dimension (L3) which represents between 10 and 50%, and preferably between 20 and 40%, of an axial dimension (L2) of the disk (114a) measured between its first and second radial annular faces (134, 136).

8. Satellite carrier (110) according to any one of claims 2 to 7, wherein it further comprises a portion of shaft (115) which is centered on the central axis (X) and of which a longitudinal end is connected to said first annular face (134).

9. Satellite carrier (110) according to any one of the preceding claims, wherein each groove (128) opens into the inside of the cage (114).

10. Satellite carrier (110) according to claim 9 depending on claim 8, wherein each groove (128) opens on the side opposite the shaft portion (115).

11. Satellite carrier (110) according to any one of the preceding claims, wherein the groove (128) is delimited by two cylindrical walls, respectively internal (128a) and external (128b), which face each other and which are connected together by a concave curved annular wall (128c).

12. Satellite carrier (110) according to any one of the preceding claims, wherein the thickness (El) of the ring of material (130) is less than a width (E3) or radial dimension of the corresponding groove (128).

13. Mechanical reducer (6) for an aircraft turbomachine, said reducer comprising a satellite carrier (110) according to any one of the preceding claims, satellites (8) which are guided by bearings whose axial ends are engaged in said first and second orifices (124a, 124b), and in particular on the internal cylindrical surfaces (125, 126) of these first and second orifices (124a, 124b), and a solar (7) which is housed in the cage (114) and which is meshed with the satellites (8).

14. Aircraft turbomachine (1), comprising a reduction gear (6) according to the preceding claim.