TURBOMACHINE INCLUDING A SPEED REDUCER HAVING MOUNTING BRACKETS CONNECTED TO A STATOR OF THE TURBOMACHINE

Abstract

The invention relates to a speed reducer (20), for an aircraft turbomachine (1) with longitudinal axis X, comprising an outer ring (24) and a ring carrier (26) fixed to the outer ring, satellite gears meshing with a sun pinion and the outer ring which is formed of two front and rear half-rings (24a, 24b), these two half-rings each having respectively a front half-flange (24ab) and a rear half-flange (24bb) extending radially outwards and which are fixed to a fixing flange (27) of the ring carrier, the ring carrier comprising a gooseneck (28) allowing the centering of the ring. According to the invention, the mounting flange extends radially between the front half-flange (24ab) and the rear half-flange (24bb), and the gooseneck has a C-shaped axial cross-section whose base (28a) is tangent to a radial plane (PR) located upstream of the front mounting half-flange. Figure 5 (for the abstract)

Description

Title of the invention: TURBOMACHINE COMPRISING A SPEED REDUCER HAVING FLANGES OF MOUNTINGS CONNECTED TO A TURBOMACHINE STATOR Scope of the invention

[0001] The present invention relates to the general field of aeronautics. It relates in particular to a mechanical speed reducer with fixing flanges connected to a stator of the turbomachine. Technical background

[0002] 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.

[0003] 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.

[0004] 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.

[0005] 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. • 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 sun. • On an epicyclic reducer, the ring is fixed and the planet carrier constitutes the output shaft of the device which rotates in the same direction as the solar. • On a differential gearbox, no element is fixed for rotation. The ring rotates in the opposite direction to the solar and satellite carrier.

[0006] 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.

[0007] There are several types of contact meshing such as with straight, helical or chevron teeth.

[0008] Figures 1 and 2 show a speed reducer IA with an epicyclic gear. The speed reducer IA comprises a fixed ring gear 2A connected to a fixed housing or stator 3A of the turbomachine via a ring carrier 4A. The speed reducer IA includes planet gears 5A that drive a planet carrier in rotation. The planet carrier is fixed to the fan shaft and is free to rotate about the longitudinal axis of the turbomachine. The ring gear 2A includes a first mounting flange 7A extending radially outwards and fixed to a second mounting flange 8A of the ring carrier 4A by means of a bolted connection. The mounting flanges 7A and 8A each comprise a surface, and these surfaces are pressed against each other by the bolts of the bolted connection. An example of a speed reducer is described in document FR-A1-3042568.

[0009] The crown 2A is formed of two half-crowns 2Aa, 2Ab, which include internal herringbone teeth meshing with external teeth of the satellites 5A. The two half-crowns also each include axial teeth 9A that mesh with each other to allow the transfer of forces from one half-crown to the other during rotation. The two half-crowns 2Aa, 2Ab are precisely positioned relative to each other by means of an orientation pin, which also ensures the alignment of the internal herringbone teeth. A shrink-fit mechanism further ensures the centering of the two half-crowns.

[0010] The gear carrier 4A has bellows to limit overloads due to the movement and misalignment of various components in the turbomachine and to transmit significant torque. The gear carrier 4A also includes a gooseneck 10A, which also serves to ensure the centering of the gears and to limit misalignment. The gooseneck 10A generally has a small radius of curvature, forming approximately a V, and is tangent to a median plane PI passing between the two half-flanges 1lAa, 1lAb of the half-crowns and perpendicular to the longitudinal axis of the turbomachine. For example, the radius of curvature of this gooseneck is 5 mm with a 45° V.

[0011] Torque transmission is achieved by friction between these surfaces and is limited to the same mounting diameter. Increasing the diameter of the mounting flanges could be a solution to increase the torque transmission capacity. However, on the one hand, the number of screws that can be mounted on these flanges may be limited, and on the other hand, this could directly impact the diameter of the speed reducer and its integration into the already limited space of the turbomachine. Furthermore, the manufacturability of such a ring carrier and ring gear is complex. The carrier- The crown gear includes holes in the bellows for lubricant drainage, which complicates manufacturing and assembly. The gooseneck can obstruct access to the numerous bolts used for mounting and dismounting the crown gear carrier and crown gear. Modifying the gooseneck changes the crown gear carrier's stiffness, which can directly affect gearbox misalignment.

[0012] There is a need to resolve all or part of the aforementioned drawbacks. Summary of the invention

[0013] The objective of the present invention is to provide a solution which makes it easy to connect the crown to the stator of the turbomachine for the transmission of torque and which is simple and economical to manufacture and assemble, while ensuring optimized stiffness.

[0014] We achieve this objective in accordance with the invention by means of a speed reducer for an aircraft turbomachine having a longitudinal axis, the speed reducer comprising a sun pinion, satellite pinions, an outer ring gear and a ring carrier fixed to the outer ring gear, the satellite pinions being meshed on one side with the sun pinion and on the other side with the outer ring gear, and the outer ring gear being formed of two front and rear half-rings which each respectively have a front fixing half-flange and a rear fixing half-flange extending radially outwards and which are fixed to a fixing flange of the ring carrier by fixing members, the ring carrier comprising a gooseneck adapted to allow centering of the ring gear,the mounting flange extending radially between the front mounting half-flange and the rear mounting half-flange, and in that the gooseneck has a C-shaped axial section whose bottom is tangent to a radial plane located upstream of the front mounting half-flange.

[0015] Thus, this solution makes it possible to achieve the aforementioned objective. In particular, mounting the ring carrier flange between the two ring half-flanges provides uniform stiffness, firstly between the ring half-flanges, and secondly between the ring and the turbomachine stator. The stiffness is, in particular, optimized. Indeed, the optimized stiffness for a stator component of a turbomachine gearbox is defined by the need for centering and limiting misalignments due to internal meshing forces within the gearbox and misalignments due to the turbomachine.

[0016] The operation of this type of reducer requires a stator component with an effective means of flexibility (optimized stiffness) enabling:

[0017] - to limit overloads in the system due to motor movements,

[0018] - to have a healthy dynamic state of the entire reduction gear and turbomachine assembly,

[0019] - transmit an important couple.

[0020] The gooseneck also facilitates mounting on the crown by allowing for its movement and the passage of the fasteners for mounting the retaining flanges. The gooseneck configuration also improves the manufacturability of the crown carrier. Furthermore, this arrangement is simple and does not entail substantial modifications to the speed reducer or the stator.

[0021] The speed reducer also includes one or more of the following features, taken alone or in combination:

[0022] - the swan neck has a radius of curvature which is equal to 0.5 times the height radial of the front and rear half-flanges for attachment.

[0023] - the speed reducer includes lubricant evacuation means arranged at less so in the front and rear half-braces of attachment.

[0024] - the evacuation means include ejection holes which are formed at less partly in the wall of the front and rear half-bridles and which extend radially.

[0025] - the front half-flange for fixing, the rear half-flange for fixing and the flange of the crown carrier fixing respectively include axial fixing holes through which the fixing members pass, the axial fixing holes being arranged circumferentially around the longitudinal axis.

[0026] - the fastening elements include axial screws or axial bolts passing through the openings.

[0027] - the crown holder includes means of flexibility such as at least one bellows.

[0028] - the crown holder includes through openings that pass radially on either side of the wall of the crown holder.

[0029] - - the ring is connected to a housing of the turbomachine and is fixed in rotation relative to the longitudinal axis.

[0030] — the ring is connected to a shaft of the turbomachine and is rotationally mobile around the longitudinal axis.

[0031] The invention also relates to an aircraft turbomachine, having a longitudinal axis and a speed reducer as above.

[0032] The invention further relates to an aircraft equipped with such a turbomachine. Brief description of the figures

[0033] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent upon reading the detailed explanatory description that follows, of embodiments of the invention given by way of purely illustrative and non-limiting examples, with reference to the schematic drawings. attached documents in which:

[0034] Fig. 1 represents a mechanical reducer of a turbomachine according to the prior art;

[0035] Fig. 2 represents an example of a crown according to the prior art;

[0036] Fig. 3 represents an example of a turbomachine according to the invention;

[0037] Fig. 4 is a detailed view of an example of a speed reducer according to the invention;

[0038] Figure 5 is a partial axial cross-sectional view of an embodiment of a speed reducer according to the invention; and

[0039] Figure 6 is a partial axial cross-sectional view of another embodiment of a speed reducer according to the invention. Detailed description of the invention

[0040] Figures 1 and 2 represent a mechanical speed reducer intended to equip a turbomachine, in particular a ring, and which have already been described previously.

[0041] Figure 3 shows a turbomachine 1 with longitudinal axis X. The turbomachine 1 illustrated is a twin-spool, twin-flow turbomachine 1 intended for mounting on an aircraft. Of course, the turbomachine can be a single-flow turbojet or a turboprop equipped with a single unfaired propeller or a pair of counter-rotating, unfaired propellers, known as an "open rotor." The invention can be applied to other fields in which a mechanical speed reducer is used.

[0042] In the present invention, the terms "upstream" and "downstream" are defined with respect to the flow of gases in the turbomachine and here along the longitudinal axis X and to the [Fig.3] from left to right.

[0043] The turbomachine 1 comprises, in a conventional manner and from upstream to downstream, a fan S, a low-pressure compressor 1a, a high-pressure compressor 1b, an annular combustion chamber 2, a high-pressure turbine 3a, a low-pressure turbine 3b, and an exhaust nozzle 4. The high-pressure compressor 1b and the high-pressure turbine 3a are connected by a high-pressure shaft 5 and together form a high-pressure (HP) housing. The low-pressure compressor 1a and the low-pressure turbine 3b are connected by a low-pressure shaft 6 and together form a low-pressure (LP) housing.

[0044] The fan S is enclosed by a fan housing 7 which carries an external nacelle 8. The fan S generates, from an airflow F entering the fan, a primary airflow which circulates in a primary channel 9 opening into the exhaust nozzle 4 and a secondary airflow which circulates in a secondary channel 10, around the primary vein 9, opening into an ejection nozzle 11. The primary and secondary flows meet and mix downstream.

[0045] The blower S is driven by a blower shaft 12 which is driven to the low pressure shaft 6 for example by means of a speed reducer 20. The latter is generally of the planetary or epicyclic type.

[0046] In the present embodiment, the turbomachine is equipped with a speed reducer 20 formed of a gear train and known by the English acronym RGB for "Reduction Gear Box".

[0047] The gearbox 20 is positioned in the upstream part of the turbomachine, following the flow of the turbomachine's gases. A fixed structure 13, schematically comprising an upstream part 13a and a downstream part 13b, forms the motor housing 16 or stator and is arranged to form an enclosure 14 surrounding the gearbox 20. The motor housing 16 can, for example, be the inlet housing of the turbomachine. A lubricant mist is present in the enclosure 14. This enclosure 14 is advantageously, but not exclusively, closed upstream by seals at the level of an upstream bearing 15 allowing passage of the fan shaft 12, and downstream by seals at the level of the low-pressure shaft 6.

[0048] With reference to [Fig. 4], the speed reducer 20 is here of the epicyclic type. It comprises three components: a sun gear 21, planet gears 22, and a planet carrier 23, all of which are rotatable. The rotational speed of one of these components depends, in particular, on the difference in speeds between the other two components.

[0049] At the input, the gearbox 20 is connected to the low-pressure shaft 6, for example, via splines 39. These splines advantageously extend parallel to the longitudinal axis X. Thus, the low-pressure shaft 6 drives the solar element 21 (or internal planetary gear). Typically, the solar element 21, whose axis of rotation coincides with that of the longitudinal axis X of the turbomachine, drives the satellites 22, which are evenly distributed over the same diameter around the longitudinal axis of rotation X. This diameter is equal to twice the operating center distance between the solar element and the satellites. The number of satellites is generally defined as between three and seven for this type of application.

[0050] Advantageously, the solar 21 is rotationally fixed to the low pressure shaft 6 and the satellite carrier 23 is rotationally fixed to the blower shaft 12.

[0051] The set of satellites 22 is held by a frame called a satellite carrier 23. Each satellite 22 rotates about its own axis. Each satellite 22 meshes with an external ring gear 24 (or external planetary gear).

[0052] The outer ring 24 is fixed or immobile in rotation with respect to the longitudinal axis X.

[0053] At the output, the set of satellites 22 drives the planet carrier 23 in rotation around the X-axis of the turbomachine. The outer ring 24 is fixed to a housing of the turbomachine or stator (such as the housing 16) via a ring carrier 26 described later. The planet carrier 23 is fixed and rotationally fixed to the fan shaft 12.

[0054] Optionally, each satellite 22 is mounted to rotate freely using a bearing (not shown), for example, a roller bearing or a hydrodynamic bearing. Generally, a hydrodynamic bearing is supplied with "low" pressures (usually less than 10 bar). The rotation of the bearing allows the lubricant wedge to be pressurized and the satellites and bearings to separate. Each bearing is mounted on one of the axes of the satellite carrier 23, and all the axes are positioned relative to each other using one or more structural frames of the satellite carrier 23. Each satellite 22 meshes with external teeth of the sun gear 21 and internal teeth of the outer ring gear 24. The internal teeth of the outer ring gear 24 can be straight (parallel to the longitudinal axis), helical, or herringbone.

[0055] There is a number of shafts and bearings equal to the number of satellites. For reasons of operation, assembly, manufacturing, control, repair or replacement, the shafts and the chassis may be separated into several parts.

[0056] For the same reasons mentioned above, the teeth of a reducer 20 can be separated into several helices.

[0057] Still referring to [Fig.4], the outer ring 24 is separated into two half-rings 24a, 24b: • A front half-crown 24a consisting of a rim 24aa and a radially extending front mounting flange 24ab. The front helix of the reduction gear teeth is located on the rim 24aa. This front helix meshes with that of the satellite 22, which in turn meshes with that of the solar 21. • A rear half-crown 24b consisting of a rim 24ba and a rear mounting half-flange 24bb extending radially. The rear helix of the reduction gear teeth is located on the rim. This rear helix meshes with that of the satellite 22, which meshes with that of the solar 21.

[0058] Advantageously, but not exclusively, the mounting half-flange 24ab of the front half-crown 24a and the mounting half-flange 24bb of the rear half-crown 24b form a first mounting flange 25 of the crown. The first mounting flange 25 is annular and extends radially outwards. The crown (or the two half-crowns) 24 includes an axis of revolution which is preferably coaxial with the axis of the turbomachine. The first mounting flange 25 extends radially from a radially external surface 24c. The internal radial surface 24d radially opposite includes 32 propellers (formed from the front and rear propellers) which mesh with the teeth of the satellites 22.

[0059] With reference to [Fig. 5], a gear carrier 26 connects the outer gear 24 to the turbomachine stator and, for example, to the housing 16. The gear carrier 26 transfers the torque from the speed reducer 20 to the turbomachine stator. Advantageously, but not exclusively, the gear carrier 26 is annular and centered on the turbomachine axis. To this end, the gear carrier 26 includes, at a first end 26a, a second mounting flange 27. In this example, the latter extends radially inward (towards the longitudinal axis X).

[0060] Advantageously, but not exclusively, the front mounting half-flange 24ab and rear mounting half-flange 24bb comprise, respectively, openings 31a and 31b which pass through their walls on either side and each have an axis A parallel to the longitudinal axis X. The openings 31a and 31b are regularly spaced around the longitudinal axis X and are coaxial with each other. The number of openings 31a and 31b is, for example, between 5 and 10.

[0061] The openings 31a, 31b are designed to allow the passage of fasteners 40 (shown in dashed lines in [Fig. 4]). In other words, the axial openings 31a, 31b are traversed by the fasteners 40. The fasteners 40 are advantageously, but not exclusively, threaded elements of the screw-nut type. Of course, the fasteners 40 can be any threaded element (such as axial bolts) cooperating with a clamping element or any other suitable element that allows for easy and damage-free assembly and disassembly of the parts fitted with them.

[0062] As shown in [Fig. 5], the second mounting flange 27 extends radially between the front mounting half-flange 24ab and the rear mounting half-flange 24bb. In other words, the mounting flange 27 is sandwiched between the two mounting half-flanges 24aa, 24bb of the ring 24. This configuration prevents a difference in stiffness between the front and rear half-rings.

[0063] The mounting flange 27 also includes openings 36 that pass axially through its wall on either side. Advantageously, but not exclusively, the openings 36 are coaxial with the openings 31a, 31b of the front and rear mounting half-flanges 24ab, 24bb in the installed configuration. The number of openings 36 is identical here to that of the openings 31a, 31b.

[0064] Since the fixing flange 27 is axially arranged between the front and rear fixing half-flanges 24ab, 24bb, the fixing members 40 pass through the orifices 36. The fixing members 40 are arranged so as to clamp the half and second flanges 24ab, 24bb and the fixing flange 27.

[0065] Advantageously and with reference to [Fig. 4], the fastening members 40 com The screws 41 (shown in dashed lines) extend axially and apply an axial force to tighten the mounting flanges. The number of fasteners 40 is the same as the number of holes 31a, 31b, and 36, respectively. The head 41a (shown in dashed lines) of the screw 41 is pressed against a downstream face of one half-flange, and a nut 42 (shown in dashed lines), which allows the screw to tighten the flanges 24ab, 24bb, and 27, is mounted on the threaded shank of the screw 41 on the other half-flange side.

[0066] In [Fig. 5], the crown carrier 26 advantageously, but not exclusively, includes at a second end 26b, a connecting flange 43 which is intended to be fixed to a stator mounting part (such as the housing 16) of the turbomachine. In the present example, the flange 43 extends radially outwards.

[0067] The crown carrier 26 includes a gooseneck 28 configured to maintain the predetermined stiffness of the crown carrier 26 at the level of the half-flanges and mounting flange 27. The gooseneck 28 extends from one end of the mounting flange 27 of the crown carrier 26. The gooseneck 28 has a C-shaped axial cross-section, the bottom of which 28a is tangent to a radial plane PR located upstream of the front mounting half-flange 24ab. In this way, the gooseneck 28 is larger than goosenecks of the prior art. Such a configuration allows the target stiffness of the crown carrier 26 to be respected with the sandwich type mounting of the flanges 24ab, 24bb, 27. This shape also makes it easier to mount the fixing flange 27 between the two half-flanges 24ab, 24bb of the crown 24 and also to facilitate the manufacturability of the crown carrier 26 itself.

[0068] According to an example embodiment, the radius of curvature of the gooseneck 28 (whose axis is perpendicular to the longitudinal axis X) is equal for example to 0.5 times the radial height (Hl) of the front and rear fixing half-flanges 24ab, 24bb and / or of the fixing flange 27.

[0069] Advantageously, the gear carrier 26 includes flexibility means 29 configured to, on the one hand, limit overloads in the turbomachine due to the movement of certain components thereof and / or the speed reducer 20, and on the other hand, obtain a uniform and stable distribution of dynamic loads. In the present example, the flexibility means 29 include at least one bellows 30. The gear carrier 26 includes a portion equipped with several bellows 29.

[0070] Advantageously, but not limitingly, the reducer 20 includes lubricant evacuation means 32 arranged at least in the front and rear fixing half-flanges 24ab, 24bb of the ring 24.

[0071] In the example of [Fig. 6], the evacuation means 32 comprise ejection holes 33a, 33b which are formed at least partially in the wall of the front and rear half-flanges 24ab, 24bb of the crown 24. Advantageously, but not limitingly Specifically, the ejection holes 33a, 33b extend radially. Several ejection holes 33a, 33b are distributed around the longitudinal axis X. According to the embodiment, the ejection holes open both inside the flange (at the radially internal surface 24d of the ring 24) and on the annular periphery 38 of the flange 25 (of the half-flanges 24ab, 24bb). The ejection holes can also be opened on an internal face 35a, 35b of each half-flange 24ab, 24bb. The mounting flange 27 allows, for example, the openings of the ejection holes to be closed so that the lubricant also slides down the wall of the mounting flange 27 before being expelled from the mounting half-flanges 24ab, 24bb.

[0072] Alternatively, the ejection holes 33a, 33b are formed in the thickness of the wall of each half-flange 24ab, 24bb.

[0073] According to an embodiment not shown, the mounting flange 27 could also include discharge holes to allow the lubricant to be evacuated from the speed reducer. The discharge holes in the mounting flange 27 could have the same shape as those in the half-flanges 24ab, 24bb or be formed within the thickness of the mounting flange 27. In this case, this increases the cross-sectional area for the lubricant to pass through the speed reducer 20.

[0074] As shown in [Fig. 6], the gear carrier 26 may include through-holes 34 that allow the lubricant to be evacuated, the path of which is indicated by the arrows L. Advantageously, the through-holes 34 pass radially through the wall of the gear carrier 26 on both sides. The through-holes are distributed around the longitudinal axis X and preferably in a regular manner. According to an advantageous feature, the gear carrier may include several rows of through-holes along the longitudinal axis X. The arrangement of these through-holes 34 also makes it possible, on the one hand, to avoid areas of lubricant retention in the turbomachine and, on the other hand, to achieve a weight reduction. The lubricant will fall by gravity into the bellows 30 and be carried through the through-holes 34.

[0075] Generally, the lubricant enters the gearbox 20 from the turbomachine stator via a distributor (not shown) by various means. The distributor is divided into two sections, each repeated with the same number of planet gears. The gearbox includes injectors that lubricate the gear teeth and arms that lubricate the planet gear bearings; these injectors and arms are connected to the distributor. The lubricant is supplied to the injector and exits through one end of it to lubricate the gear teeth. It is also supplied to the arm to circulate through the various components of the gearbox 20. The lubricant then exits through the ejection holes 33a, 33b, which are located at the interfaces with the mounting half-flanges 24ab, 4bb, and also through the through openings 34.

[0076] Advantageously, but not exclusively, the lubricant comprises oil.

Claims

Demands

1. A speed reducer (20) for an aircraft turbomachine (1) having a longitudinal axis X, the speed reducer comprising a sun pinion (21), planet gears (22), an outer ring gear (24), and a ring carrier (26) fixed to the outer ring gear (24), the planet gears (22) meshing on one side with the sun pinion (21) and on the other side with the outer ring gear (24), and the outer ring gear (24) being formed of two front and rear half-rings (24a, 24b), each having respectively a front mounting half-flange (24ab) and a rear mounting half-flange (24bb) extending radially outwards and fixed to a mounting flange (27) of the ring carrier (26) by fastening members (40), the ring carrier comprising a gooseneck (28) adapted to allow centering of the ring gear (24),characterized in that the fixing flange (27) extends radially between the front fixing half-flange (24ab) and the rear fixing half-flange (24bb) and in that the gooseneck (28) has a C-shaped axial section whose bottom (28a) is tangent to a radial plane (PR) which is upstream of the front fixing half-flange (24ab).

2. Speed ​​reducer (20) according to claim 1, characterized in that the gooseneck (28) has a radius of curvature which is equal to 0.5 times the radial height (Hl) of the front and rear fixing half-flanges (24ab, 24bb).

3. Speed ​​reducer (20) according to any one of the preceding claims, characterized in that it comprises lubricant evacuation means (32) arranged at least in the front and rear mounting half-flanges.

4. Speed ​​reducer (20) according to claim 3, characterized in that the discharge means (32) comprise discharge holes (33a, 33b) which are formed at least in part in the wall of the front and rear half-flanges (24ab, 24bb) and which extend radially.

5. Speed ​​reducer (20) according to any one of the preceding claims, characterized in that the front mounting half-flange (24ab), the rear mounting half-flange (24bb), and the mounting flange (27) of the sprocket carrier (26) respectively comprise axial mounting holes (31a, 31b, 36) through which the mounting members (40) pass, the axial mounting holes (31a, 31b, 36) being arranged circumferentially around of the longitudinal axis X.

6. Speed ​​reducer (20) according to the preceding claim, characterized in that the fastening members (40) comprise axial screws (41) or axial bolts passing through the orifices (31a, 31b, 36).

7. Speed ​​reducer (20) according to any one of the preceding claims, characterized in that the crown carrier (26) includes flexibility means (29) such as a bellows (30).

8. Speed ​​reducer (20) according to any one of the preceding claims, characterized in that the crown carrier (26) comprises through openings (34) which radially pass through the wall of the crown carrier (26).

9. Turbomachine (1), in particular for aircraft, having a longitudinal axis X, and comprising a speed reducer (20) according to any one of the preceding claims.

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