Assembly comprising a mechanical reduction gear unit and a torque transmission shaft for an aircraft turbine engine

Abstract

The invention relates to an assembly (20) comprising a mechanical reduction gear unit (10) and a torque transmission shaft (4) for an aircraft turbine engine (1), the shaft (4) comprising a first radially outer annular collar (22) at one of the axial ends thereof, the reduction gear unit (10) comprising a one-piece planet carrier (13) and comprising two annular flanges (24, 26), characterized in that a first of the flanges (24) comprises a second radially outer annular collar (30) which is applied axially and fastened to the first collar (22) by fastening elements (32) which pass through orifices (34, 36) in the first and second collars (22, 30), and in that the second collar (30) has an outside diameter (D_ext) which is greater than a diameter (D_X1) of a toothing (14x) of the ring gear (14) of the reduction gear unit (10).

Description

[0001] DESCRIPTION

[0002] TITLE: ASSEMBLY COMPRISING A MECHANICAL REDUCER AND A TORQUE DRIVE SHAFT FOR AN AIRCRAFT TURBOMACHINE

[0003] Technical field of the invention

[0004] The present invention relates to the field of mechanical reducers for turbomachinery, in particular aircraft.

[0005] Technical background

[0006] The state of the art includes in particular documents W0-A1 -2010 / 092263, FR-A1-2 987 416, FR-A1-3 011 901, FR-A1-3 041 054, FR-A1 -3 058 493, JP-B2-6 579690, EP-B1 -2 644 939, EP-B1 -1 945 970, JP-B2-6 867123 and EP-B1 -3 030 808.

[0007] 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.

[0008] Newer generations of turbofan engines, particularly those with a high bypass ratio, incorporate a mechanical gearbox to drive the fan shaft. Typically, the gearbox's purpose is to transform the high rotational speed of the power turbine shaft into a slower rotational speed for the fan shaft.

[0009] Such a gearbox 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 the planet carrier. The sun gear, ring gear, and planet carrier are planetary gears because their axes of revolution coincide with the longitudinal X-axis of the turbomachine. The planet gears each have a different axis of revolution and are evenly spaced on the same operating diameter around the axis of the planet gears. These axes are parallel to the longitudinal X-axis. Several gearbox architectures exist. In state-of-the-art turbomachinery, gearboxes are of the planetary or epicyclic type. In other similar applications, there are so-called differential or compound architectures.

[0010] - On a planetary reducer, the planet carrier is fixed and the ring forms the output shaft of the device which rotates in the opposite direction to the sun.

[0011] - 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.

[0012] - On a differential gearbox, no element is fixed in rotation. The ring rotates in the opposite direction to the solar and satellite carrier.

[0013] Gearboxes can consist of one or more meshing stages. This meshing is achieved in various ways, such as by contact, friction, or magnetic fields.

[0014] In this application, the terms "stage" or "toothing" refer to a series of teeth interlocking with a series of complementary teeth. A toothing can be internal or external.

[0015] A satellite can have one or two gear stages. A single-stage satellite has teeth that can be straight, helical, or chevron-shaped, with teeth on the same diameter. These teeth cooperate with both the sun gear and the crown gear.

[0016] In the case of an epicyclic or differential gearbox, the output torque is transmitted via the planet carrier to a torque transmission shaft. To facilitate gearbox assembly and allow for modular turbomachine mounting, it is not always possible to form the planet carrier with the torque transmission shaft as a single unit; therefore, it is necessary to connect the planet carrier to the shaft via a mechanical linkage. This linkage is generally a bolted connection using flanges.

[0017] Since the torque to be transmitted is relatively high, it is preferable for the flanges to be as large as possible (have the largest possible diameter) while minimizing their overall size. However, the larger the connecting flanges, the more likely they are to interfere with the assembly of the gearbox.

[0018] The invention offers a solution to at least some of these problems, which is simple, effective and economical.

[0019] Summary of the invention

[0020] According to a first aspect, the invention relates to an assembly comprising a mechanical reducer and a torque transmission shaft, for an aircraft turbomachine, the shaft having an elongated shape along an axis and an annular shape around this axis, the shaft comprising a first annular flange radially external to one of its axial ends, the reducer comprising a sun gear centered on the axis, a ring gear extending around the axis and the sun gear, and satellites interposed between the sun gear and the ring gear and meshed with the sun gear and the ring gear, the satellites being guided in rotation on bearings which are carried by a satellite carrier, the satellite carrier being a single piece and comprising two annular flanges centered on the axis and connected together at their outer periphery by bridges, the sun gear and the satellites being housed in the satellite carrier, and the ring gear extending around the bridges of the satellite carrier,characterized in that a first of the planet carrier flanges comprises a second radially external annular flange which is axially applied and fixed to the first flange by fastening elements which pass through orifices in the first and second flanges, and in that the second flange has an external diameter which is greater than the diameter of a tooth of the crown.

[0021] The planet carrier is connected to the shaft by a flanged connection located on the outer periphery of one of the planet carrier's flanges. The planet carrier's flange is positioned on the outer periphery of the carrier and is thus configured to transmit a relatively high torque. The flange's position, on one side of the planet carrier and the gearbox, does not interfere with the mounting of the gearbox, and in particular with the solar array, the satellites, and the ring gear, as will be described in more detail below.

[0022] This invention is notably compatible with:

[0023] - of a single or multi-stage reducer;

[0024] - of an epicycloidal or differential reducer;

[0025] - with straight or herringbone teeth.

[0026] The assembly according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0027] - the crown comprises a cylindrical rim whose inner periphery includes said teeth, and whose outer periphery is connected to a third fixing flange, the outer diameter of the second flange being greater than an outer diameter of the rim, or even greater than an outer diameter of the third flange;

[0028] - the crown is in two parts, and comprises two half-crowns assembled axially; in this case, the solar element is preferably a single piece;

[0029] - the external diameter of the flange defines the maximum external diameter of the reducer;

[0030] - the first flange defines the maximum external diameter of the shaft;

[0031] - the first and second flanges include bearing faces which are flat and perpendicular to the axis;

[0032] - the first and second flanges include bearing faces which are notched and each includes teeth engaged axially in hollows of complementary shape to the other flange in order to form a curvic-coupling type connection;

[0033] - part of said orifices of each of the flanges is formed in the teeth of the flange and another part of said orifices of each of the flanges is formed in the hollows of the flange; - the solar element is in two parts, and comprises two half-solars assembled axially; in this case, the crown is preferably a single piece;

[0034] - the first flange is separated from the second flange by an annular slot which extends continuously around the axis;

[0035] - the slit has a generally wavy shape around the axis;

[0036] - the slot crosses axially the first flange;

[0037] - the slot extends between the orifices of the first flange for the mounting of the bearings, and said second flange;

[0038] - the first flange is connected to the second flange via the said bridges, and preferably only via the said bridges.

[0039] The present invention further relates to an aircraft turbomachine comprising an assembly as described above.

[0040] The present invention further relates to a method of mounting an assembly as described above, comprising the following steps: a) mounting at least a part of the crown around the bridges of the satellite carrier and at least a part of the solar in the satellite carrier, b) mounting the satellites and bearings in the satellite carrier, and c) fixing together the first and second flanges.

[0041] Preferably, in step a), the half-crown located axially on the side of the second flange is mounted around the bridges of the satellite carrier.

[0042] Preferably, after step b) or during step c), the other half-crown is mounted around the bridges of the satellite carrier, and the half-crowns are assembled together.

[0043] Preferably, at step a), one of the solar half-frames is engaged in the satellite carrier by axial translation from one side of the reducer.

[0044] Preferably, after step b) or during step c), the other of the solar halves is engaged in the satellite carrier by axial translation from an opposite side of the reducer, and the solar halves are assembled together.

[0045] According to a second aspect, the invention relates to a solar element for a mechanical reducer of an aircraft turbomachine, the reducer having an annular shape around an axis and having internal coupling splines on its inner periphery, and at its outer periphery at least one meshing tooth, characterized in that it is formed by the assembly of two half-solars, a first half-solars having a first row of teeth of the gear, and a second half-solars having a second row of teeth of the gear as well as the internal splines.

[0046] The fact that the solar panel is made in two parts offers several mounting possibilities for the solar panel and facilitates the assembly of the reducer.

[0047] The solar device according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0048] - the first and second half-solars are coupled together by grooves, and / or fixed together by a nut;

[0049] - the solar panel comprises two coaxial cylindrical walls connected to each other by an annular veil of material which extends perpendicularly to the axis, the inner wall comprising said internal grooves, and the outer wall comprising said teeth;

[0050] - the first and second half-solars each define a part of the inner wall, a part of the veil and a part of the outer wall;

[0051] - the first half-solar has in axial section a general C shape and includes a first internal cylindrical rim forming part of the internal wall, a second external cylindrical rim forming part of the external wall and comprising the first row of teeth, and an axial part of the veil which connects the axial ends of the first and second rims;

[0052] - the second half-solar comprises a first internal cylindrical rim forming part of the internal wall and having the internal grooves, a second external cylindrical rim forming part of the external wall and having the second row of teeth, and an axial part of the web which connects the first and second rims; - the first and second half-solars have their first rims which are axially supported on each other, and / or the first and second half-solars have their second rims which are axially supported on each other;

[0053] - the first and second half-solars have their sail parts which are axially separated from each other by an axial gap;

[0054] - the first rim of the first half-solar is axially engaged on a part of the first rim of the second half-solar and includes internal coupling grooves with external grooves of this part of the first rim of the second half-solar;

[0055] - a nut is screwed onto a thread of the first rim of the second half-solar and bears axially on the first rim of the first half-solar;

[0056] - the first rim of the second half-solar has a first axial end which is surrounded by the teeth, and a second axial end, opposite to the first end, which is offset axially from the teeth and which is not surrounded by the teeth;

[0057] - the second half-solar includes an internal annular rib which defines the minimum internal diameter of the solar;

[0058] - the part of the first rim of the second half-solar which includes the external grooves also includes the rib and is connected to the rest of the second half-solar, and in particular to the rest of the first rim of the second half-solar, by a thinning of the wall giving a predetermined flexibility to the solar;

[0059] - the first and second rows of teeth are separated from each other by a median plane perpendicular to the axis, the first half-solar being located on one side of this median plane, and the other half-solar being cut by this median plane.

[0060] The present invention further relates to a mechanical reducer for an aircraft turbomachine, comprising a solar element as described above, a ring extending around the solar element, and satellites interposed between the solar element and the ring and meshed with the solar element and the ring.

[0061] The present invention also relates to an aircraft turbomachine, comprising a reducer as described above.

[0062] The characteristics of both aspects of the invention can be combined together.

[0063] Brief description of the figures

[0064] 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:

[0065] [Fig.1] Figure 1 is a schematic half-view in axial cross-section of an aircraft turbomachine,

[0066] [Fig.2] Figure 2 is a partial and highly schematic axial section of a mechanical reducer,

[0067] [Fig.3] Figure 3 is a schematic perspective view of an assembly according to the invention, this assembly comprising a shaft and a reducer which is partially shown here,

[0068] [Fig. 4] Figure 4 is a schematic front view of the reducer in Figure 3.

[0069] [Fig. 5a-5b] Figures 5a and 5b are very schematic partial axial cross-sectional views of an assembly according to the invention, and show steps in an assembly method according to the invention,

[0070] [Fig. 6] Figure 6 is a very schematic partial axial cross-sectional view of an assembly according to the invention, and shows another step of an assembly method according to the invention,

[0071] [Fig.7] Figure 7 is a schematic axial cross-sectional view of a solar array formed by the assembly of two half-solars,

[0072] [Fig. 8] Figure 8 is a very schematic axial cross-sectional view of one embodiment of an assembly according to the invention, [Fig. 9] Figure 9 is a schematic perspective view of another embodiment of an assembly according to the invention, this assembly comprising a shaft and a reducer which is partially shown here, [Fig. 10] Figure 10 is a schematic side view of the assembly of Figure 9, and

[0073] [Fig.11] Figure 11 is a schematic perspective view of the tree of the whole of Figure 9.

[0074] Detailed description of the invention

[0075] Figure 1 depicts a turbomachine 1 which, in a conventional manner, comprises a rotational shaft X, a fan S, a low-pressure compressor 1a, a high-pressure compressor 1b, an annular combustion chamber 1c, a high-pressure turbine 1d, a low-pressure turbine 1e, and an exhaust nozzle 1h. The high-pressure compressor 1b and the high-pressure turbine 1d 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.

[0076] The blower S is driven by a blower shaft 4 which is driven to the BP shaft 3 by means of a reducer 10. This reducer 10 is generally of the planetary or epicycloidal type.

[0077] The following description relates to a planetary type reducer in which the ring gear is mobile in rotation.

[0078] The gearbox 10 is positioned in the upstream part of the turbomachine. A fixed structure, schematically comprising 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 a bearing allowing the passage of the fan shaft 4, and downstream by seals at the point where the BP shaft 3 passes through. Figure 2 shows a gearbox 10 which can take on different configurations depending on whether certain parts are fixed or rotating. At the input, the gearbox 10 is connected to the BP shaft 3, for example, via internal splines 7a. Thus, the BP shaft 3 drives a planetary gear called the sun gear 11.Typically, the solar 11, whose axis of rotation coincides with that of the turbomachine X, drives a series of pinions called satellites 12, which are equidistant on the same diameter around the axis of rotation X. This diameter is equal to twice the operating center distance between the solar 11 and the satellites 12. The number of satellites 12 is generally defined between three and seven for this type of application.

[0079] The set of satellites 12 is held by a frame called the satellite carrier 13. Each satellite 12 rotates around its own Y axis, and meshes with the ring 14.

[0080] ■ In this 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.

[0081] Each satellite 12 is mounted to rotate freely using a bearing 8, for example, a roller bearing or hydrodynamic bearing. Each bearing 8 is mounted on one of the axes 13a of the satellite carrier 13, and all the axes 13a are positioned relative to each other using a cage of the satellite carrier 13. There is a number of 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 cage may be separated into several parts.

[0082] In this application, an axis 13a is referred to as a bearing or support axis.

[0083] For the same reasons mentioned previously, the teeth of a reduction gear can be separated into several helices, each with a median plane. In the example shown, the ring gear 14 is separated into two half-rings: ■ An upstream half-ring gear 14a consisting of a rim 14aa and a mounting flange half 14ab. The upstream helix of the reduction gear teeth is located on the rim 14aa. This upstream helix meshes with that of the satellite gear 12, which meshes with that of the solar gear 11.

[0084] ■ A downstream half-crown 14b consisting of a rim 14ba and a mounting half-flange 14bb. On the rim 14ba is the downstream helix of the reduction gear teeth. This downstream helix meshes with that of the satellite 12 which meshes with that of the solar 11.

[0085] The mounting half-flange 14ab of the upstream crown 14a and the mounting half-flange 14bb of the downstream crown 14b form the mounting flange 14c of the crown. The crown 14 is fixed to a crown carrier by assembling the mounting flange 14c of the crown and the mounting flange 15a of the crown carrier 15 using a bolted assembly, for example.

[0086] The arrows in Figure 2 illustrate the oil flow within the gearbox 10. The oil enters the gearbox 10 from the stator section 5 via a distributor 16 by various means, which will not be detailed in this view as they are specific to one or more types of architecture. The distributor 16 is generally divided into two parts, each typically repeated with the same number of planetary gears 12. The injectors 17a lubricate the gear teeth, and the arms 17b lubricate the bearings. 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 the arm 17b and flows through the inlet 17d of the bearing shaft 13a. The oil then circulates in an internal cavity 13b of the shaft 13a and then exits through orifices 13c in order to lubricate the bearings 8 of the satellites 12.

[0087] Figures 3 to 6 illustrate a first embodiment of an assembly 20 according to the invention.

[0088] According to the invention, an assembly 20 comprises a mechanical reducer 10 and a torque transmission shaft 4.

[0089] Shaft 4 is for example the aforementioned drive shaft of the blower S. The reducer 20 is of the epicyclic or differential type and its planet carrier 13 is mobile in rotation around the axis X and connected to the shaft 4 which transmits an output torque from the reducer 10 to the blower S in order to drive it in rotation around the axis X.

[0090] Shaft 4 has an elongated shape along the X-axis and an annular shape around this X-axis. Shaft 4 includes a first annular flange 22 radially external to one of its axial ends, here downstream. Its opposite axial end, here upstream, is connected to the blower S.

[0091] We can see, in particular in figure 6, that the flange 22 defines the maximum external diameter D_max of the shaft 4.

[0092] The reducer 10 includes a solar 11 centered on the X axis, a ring 14 extending around the X axis and the solar 11, and satellites 12 intercalated between the solar 11 and the ring 14 and meshed with the solar 11 and the ring 14.

[0093] The satellites 12 are guided in rotation on bearings 8 which are carried by the satellite carrier 13.

[0094] The satellite carrier 13 is monobloc and comprises two annular flanges 24, 26, respectively upstream and downstream, centered on the X axis and connected together at their external periphery by bridges 28.

[0095] The solar array 11 and the satellites 12 are housed in the satellite carrier 13, and the crown 14 extends around the bridges 28 of the satellite carrier 13.

[0096] According to one aspect of the invention, one of the flanges 24 of the satellite carrier 13 comprises a second radially external annular flange 30 which is applied axially and fixed to the first flange 22 by fastening elements 32 which pass through orifices 34, 36 of the first and second flanges 22, 30.

[0097] The second flange 30 advantageously has an external diameter D_ext which is greater than a diameter D_X1 of a tooth 14x of the crown 14.

[0098] Preferably, the external diameter D_ext of the flange 30 represents the maximum external diameter of the reducer 10. In the example shown, it is the upstream flange 24 that carries the flange 30. The downstream flange 26 includes a central orifice 38 which is configured to allow the engagement of the solar 11 and the satellites 12 in the satellite carrier 13. This central orifice 38 therefore has a diameter D_Y1 greater than the external diameters of the solar 11 and the satellites 12.

[0099] The flanges 24, 26 include mounting holes 40, 42 for the axial ends of the bearings 8. The holes 40 of the flange 24 are aligned with the holes 42 of the flange 26. The holes 40 of the flange 24 are distributed around the X axis and may have diameters D_Y2 smaller than the diameters D_Y3 of the holes 42 of the flange 26, as in the example shown.

[0100] The bridges 28 are distributed around the X axis and define between them openings 44 which are intended to be crossed axially by teeth 12x of the satellites 12 in view of their meshing with the internal teeth 14x of the crown 14. The teeth 12x of the satellites 12 also mesh with an external teeth 11x of the sun 11.

[0101] As can be seen in Figures 3 and 4, the flange 24 can be separated from the second flange 30 by an annular slot 46 that extends continuously around the X-axis. This slot 46 may have a corrugated ring shape, particularly around the X-axis. The slot 46 may pass axially through the first flange 24. The slot 46 may extend between the holes 40 of the first flange 24 for mounting the bearings 8 and the second flange 30. The flange 24 can then be connected to the second flange 30 via the bridges 28.

[0102] According to alternative embodiments of the invention, the solar element 11 can be a single piece (Figure 8) or made by assembling two parts (Figures 5b, 6 and 7). Furthermore, the ring 14 can be a single piece (Figures 5a, 5b and 6) or made by assembling two parts (Figures 2 and 8).

[0103] Generally, the ring gear 14 comprises a cylindrical rim whose inner periphery includes the teeth 14x, and whose outer periphery is connected to a third mounting flange 14c. The outer diameter D_ext of the second flange 30 may be greater than the outer diameter D_X2 of the rim, or even greater than the outer diameter D_X3 of the third flange 14c. Alternatively, D_X3 could be greater than D_ext. In the case where the ring gear 14 is in two parts, it comprises two half-rings 14a, 14b assembled axially (Figure 2).

[0104] In the case where the solar 11 is in two parts, it comprises two half-solars 11a, 11b assembled axially (figure 7).

[0105] Figure 7 illustrates one embodiment of this type of solar 11.

[0106] A first half-solar 11a has a first row of teeth 11x1 of the teeth 11, and the second half-solar 11b has a second row of teeth 11x2 of the teeth 11x as well as internal grooves 7a for coupling to the aforementioned shaft 3 (figure 2).

[0107] The half-solars 11 a, 11 b are preferably coupled together by grooves 50, and / or fixed together by a nut 52.

[0108] In the example shown, the solar 11 comprises two coaxial cylindrical walls 54, 56 connected to each other by an annular veil of material 58 which extends perpendicularly to the X axis.

[0109] The internal wall 54 has the internal grooves 7a, and the external wall 56 has the teeth 11 x and therefore the rows of teeth 11x1, 11x2.

[0110] The half-solars 11 a, 11 b can each define a part of the inner wall 54, a part of the veil 58 and a part of the outer wall 56.

[0111] The half-solar 11 a, here upstream, has in axial section a general C shape and includes a first internal cylindrical rim 54a forming part of the internal wall 54, and a second external cylindrical rim 56a forming part of the external wall 56 and comprising the first row of teeth 11x1.

[0112] The half-solar 11a further includes an axial part 58a of the veil 58 which connects axial ends of the first and second rims 54a, 56a.

[0113] The half-solar 11b, here downstream, includes a first internal cylindrical rim 54b forming part of the internal wall 54 and having the internal grooves 7a, and a second external cylindrical rim 56b forming part of the external wall 56 and having the second row of teeth 11x2.

[0114] The half-solar 11b further includes an axial part 58b of the veil 58 which connects the first and second rims 54b, 56b.

[0115] The half-solars 11a, 11b preferably have their first edges 54a, 54b axially supported on each other, and / or their second edges 56a, 56b axially supported on each other. The bearing faces of these edges are designated by the letter C in Figure 7.

[0116] The half-sun lenses 11a and 11b have their sail sections 58a and 58b preferably separated axially from each other by an axial clearance J. This limits and localizes the contacts, allowing for better dimensioning and minimizing the risk of fretting, for example. It also ensures more precise machining.

[0117] In the example shown, the first rim 54a is axially engaged on a part of the rim 54b and includes internal grooves 50a for coupling with external grooves 50b of this part of the rim 54b.

[0118] Nut 52 is screwed onto a thread of rim 54b and bears axially on rim 54a.

[0119] As in the example shown, the rim 54b has a first axial end 54b1 which is surrounded by the teeth 11x, and a second axial end 54b2, opposite the first end 54b1, which is offset axially from the teeth 11x and is not surrounded by the teeth 11x.

[0120] The rim 54a can have its axial end 54a1 opposite the veil 58 which is surrounded by the toothing 11x.

[0121] The half-solar 11 b may include an internal annular rib 60 which defines the minimum internal diameter D_min of the solar 11.

[0122] Preferably, the portion of the rim 54b that includes the external grooves 50b further includes the rib 60 and is connected to the rest of the half-solar 11b, and in particular to the rest of the rim 54b, by a wall thinning 62 conferring a predetermined flexibility to the solar 11. The rows of teeth 11x1, 11x2 are preferably separated from each other by a median plane H perpendicular to the X-axis. The half-solar 11a may be located on one side of this median plane H. The half-solar 11b may be cut by this median plane.

[0123] The first and second flanges 22, 30 may include bearing faces 64 which are flat and perpendicular to the X axis, as is the case in figures 3 to 8.

[0124] In the variant illustrated in Figures 9 to 11, the first and second flanges 22, 30 comprise bearing faces 64 which are notched and each includes teeth 66 engaged axially in recesses 68 of complementary shape to the other flange in order to form a curvic-coupling type connection. This type of connection improves the transmission of torque through the flanges 22, 30.

[0125] Part of the orifices 34, 36 of each of the flanges 22, 30 is formed in the teeth 66 of the flange and another part of the orifices 34, 36 of each of the flanges is formed in the hollows 68 of the flange.

[0126] We will now describe a method for assembling a set 20 according to the invention.

[0127] The process includes a first step a) in which at least part of the crown 14 is mounted around the bridges 28 of the satellite carrier 13, and at least part of the solar 11 is mounted in the satellite carrier 13 (Figure 5a).

[0128] The process includes another step b) in which the satellites 12 and the bearings 8 are engaged in the satellite carrier 13 (figure 5b).

[0129] The process includes another step c) in which the flanges 22, 30 are fixed together, in particular by the fixing elements 32 (figure 6).

[0130] In the aforementioned case where the ring 14 is formed by the assembly of two half-rings 14a, 14b, step a) includes mounting the solar 11, preferably monobloc, in the satellite carrier 13. The half-ring 14a located axially on the side of the flange 30 is mounted in step a) around the bridges 28 of the satellite carrier 13, as illustrated in figure 8. After step b) or during step c), the other half-ring 14b is mounted around the bridges 28 of the satellite carrier 13, and the half-rings 14a, 14b are assembled together.

[0131] In the aforementioned case where the solar element 11 is formed by the assembly of two half-solar elements 11a, 11b, step a) comprises mounting the ring 14, preferably a single piece, around the satellite carrier 13. One of the half-solar elements 11a is engaged in step a) in the satellite carrier 13 by axial translation from one side of the reducer 10. After step b) or during step c), the other half-solar element 11b is engaged in the satellite carrier 13 by axial translation from an opposite side of the reducer 10, as in step a). The half-solar elements 11a, 11b are then assembled together.

Claims

DEMANDS 1. An assembly (20) comprising a mechanical gearbox (10) and a torque transmission shaft (4) for an aircraft turbomachine (1), the shaft (4) having an elongated shape along an axis (X) and an annular shape about this axis (X), the shaft (4) comprising a first annular flange (22) radially external to one of its axial ends, the gearbox (10) comprising a sun gear (11) centered on the axis (X), a ring gear (14) extending around the axis (X) and the sun gear (11), and planet gears (12) interposed between the sun gear (12) and the ring gear (14) and meshed with the sun gear (11) and the ring gear (14), the planet gears (12) being guided in rotation on bearings (8) which are supported by a planet carrier (13), the planet carrier (13) being a single piece and comprising two annular flanges (24, 26) centered on the axis (X) and connected together at their outer periphery by bridges (28), the solar (11) and the satellites (12) being housed in the satellite carrier (13),and the crown (14) extending around the bridges (28) of the planet carrier (13), characterized in that a first of the flanges (24) of the planet carrier (13) comprises a second radially external annular flange (30) which is axially applied and fixed to the first flange (22) by fastening elements (32) which pass through orifices (34, 36) of the first and second flanges (22, 30), and in that the second flange (30) has an external diameter (D_ext) which is greater than a diameter (D_X1) of a tooth (14x) of the crown (14), and in that the first and second flanges (22, 30) comprise bearing faces (64) which are notched and each comprises teeth (66) axially engaged in recesses (68) of complementary shape to the other flange in order to form a connection of the type curvic coupling.

2. Assembly (20) according to claim 1, wherein the crown (14) comprises a cylindrical rim whose inner periphery comprises said teeth (14x), and whose outer periphery is connected to a third flange of fixing (14c), the external diameter (D_ext) of the second flange (30) being greater than an external diameter (D_X2) of the rim, or even greater than an external diameter (D_X3) of the third flange (14c).

3. Assembly (20) according to claim 1 or 2, wherein the crown (14) is in two parts, and comprises two half-crowns (14a, 14b) assembled axially.

4. Assembly (20) according to any one of the preceding claims, wherein the external diameter (D_ext) of the second flange (30) defines the maximum external diameter of the reducer (10).

5. Assembly (20) according to any one of the preceding claims, wherein the first flange (22) defines the maximum external diameter (D_max) of the shaft (4).

6. Assembly (20) according to any one of the preceding claims, wherein a part of said orifices (34, 36) of each of the flanges (22, 30) is formed in the teeth (66) of the flange and another part of said orifices of each of the flanges is formed in the hollows (68) of the flange.

7. Assembly (20) according to any one of claims 1, 2 and 4 to 6, wherein the solar (11) is in two parts, and comprises two half-solars (11a, 11b) assembled axially.

8. Assembly (20) according to any one of the preceding claims, wherein the first flange (24) is separated from the second flange (30) by an annular slot (46) which extends continuously around the axis (X).

9. Assembly (20) according to claim 8, wherein the slot (46) has a general wavy shape around the axis (X).

10. Assembly (20) according to claim 8 or 9, in which the slot (46) passes axially through the first flange (24).

11. Assembly (20) according to any one of claims 8 to 10, wherein the slot (46) extends between orifices (40) of the first flange for mounting the bearings (8), and said second flange (30).

12. Assembly (20) according to any one of the preceding claims, wherein the first flange (24) is connected to the second flange (30) via said bridges (28).

13. Aircraft turbomachine (1), comprising an assembly (20) according to any one of the preceding claims.

14. Method of mounting an assembly (20) according to any one of claims 1 to 12, comprising the following steps: a) mounting at least a part of the ring (14) around the bridges (28) of the satellite carrier (13) and at least a part of the solar (11) in the satellite carrier (13), b) mounting the satellites (12) and the bearings (8) in the satellite carrier (13), and c) fixing together the first and second flanges (22, 30).

15. Method according to claim 14, the assembly being as defined in claim 3, wherein, in step a), the half-crown (14a) located axially on the side of the second flange (30) is mounted around the bridges (28) of the planet carrier (13), and, after step b) or during step c), the other half-crown (14b) is mounted around the bridges (28) of the planet carrier (13), and the half-crowns (14a, 14b) are assembled together.

16. Method according to claim 14, the assembly being as defined in claim 7, wherein, in step a), one of the solar halves (11 a) is engaged in the satellite carrier (13) by axial translation from one side of the reducer (10), and, after step b) or during step c), the other of the solar halves (11 b) is engaged in the satellite carrier (13) by axial translation from an opposite side of the reducer (10), and the solar halves (11 a, 11 b) are assembled together.

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