TURBOMACHINE MODULE MOUNTING DEVICE

Abstract

Device (40) for securing turbomachine modules, this device (40) comprising: - a first nut (50), called the main nut, - a second nut (52), called the retaining nut, which includes an external thread (62) adapted to cooperate with the first nut (50), and - a third nut (54), called the intermediate nut (54), this intermediate nut (54) being axially movable within the first nut (50). Figure for the abbreviation: Figure 4

Description

Title of the invention: TURBOMACHINE MODULE MOUNTING DEVICE Technical field of the invention

[0001] The present invention relates to a device for fixing modules of a turbomachine, in particular of an aircraft. Technical background

[0002] It is known to produce a turbomachine by assembling several modules. In practice, the turbomachine extends along a longitudinal axis and its modules represent axial sections of the turbomachine which are arranged and fixed axially one after the other along the longitudinal axis.

[0003] Fig. 1 represents, for example, the assembly of two modules 10, 12. The module 10 on the left is a low-pressure module which includes a blower 14, a low-pressure compressor 16 and an intermediate housing 18 which is connected to bearing supports 20 for bearings 22 that guide a shaft 24 for driving the blower 14 and the rotor of the low-pressure compressor 16. The intermediate housing 18 is further connected to a blower housing 25 which extends around the blower 14.

[0004] The module 12 on the right is a high-pressure module comprising a high-pressure compressor 26, a combustion chamber 28 and a high-pressure turbine 30. The rotors of the high-pressure compressor 26 and the high-pressure turbine 30 are connected to each other by a high-pressure shaft 32. The module 12 is traversed axially by a section 34 which extends axially inside the high-pressure shaft 32 and whose upstream end 34a must be fixed and secured to the intermediate housing 18 of the module 10.

[0005] This fastening is achieved by means of a special fastening device 40 which is accessible only from inside the modules 10, 12. This fastening device 40 is of the captive nut type. A nut, called the main nut, is pre-mounted captive on one of the modules, in this case module 10 of [Fig. 1], and the free end 34a of the section 34 of the second module 12 is axially engaged in the first module 10 (see arrow in [Fig. 1]) up to the level of the nut which is then screwed onto this free end 34a.

[0006] In the current technique, a fastening device 40 of this type practically comprises three elements, namely the first nut or main nut, a second nut or retaining nut, and an intermediate annular piece mounted in the main nut and which serves to secure the device 40 to the first module 10.

[0007] The main nut includes two threads, a first one for screwing onto the second module 12 and a second one for screwing onto the second nut.

[0008] The second nut is screwed into the first nut, and the assembly formed by the main nut and the second nut is axially retained by the intermediate piece. The main nut is left standing and is free to rotate on itself, but cannot be axially removed.

[0009] This is the intermediate piece which is intended to be fixed to the first module 10 by means of added pins, before the assembly of modules 10, 12. In practice, this operation is long and complex because the pins are difficult to access as the assembly environment of the device 40 is very restricted.

[0010] The invention proposes an improvement to this technology which in particular makes it possible to simplify the fastening device and its use for the assembly of turbomachine modules. Summary of the invention

[0011] The present invention relates to a device for fixing modules of turbomachine, this device comprising:

[0012] - a first nut, called the main nut, which includes a first internal thread having a first diameter, and a second internal thread having a second diameter greater than the first diameter, the first and second threads extending around the same axis and being axially separated from each other by a first annular stop face which extends perpendicularly to the axis and which is oriented towards the second thread,

[0013] - a second nut, called a retaining nut, which includes an external thread suitable to cooperate with the second thread of the first nut, this second nut having a second annular stop face which extends perpendicularly to the axis and is oriented towards the first thread, and

[0014] - an intermediate annular piece mounted inside the first nut and axially interposed between the first and second threads, this intermediate piece comprises third and fourth annular stop faces which extend perpendicularly to the axis and which are located respectively opposite the first and second annular stop faces,

[0015] characterized in that the intermediate part, called the intermediate nut, comprises an internal thread having a third diameter between the first and second diameters,

[0016] in that the intermediate nut comprises an external annular rim which is serrated, and the first nut comprises an internal annular rim which is serrated and which is located between the first annular stop face and the second thread,

[0017] and in that, when the second nut is screwed into the first nut, the intermediate nut remains axially mobile between the first and second annular stop faces, in particular between a first position in which the serrated edges are axially engaged with each other and cooperate by abutment in a circumferential direction with each other so that the intermediate nut is rotationally fixed to the first nut around the axis, and a second axial position in which the serrated edges are axially disengaged from each other so that the intermediate nut can move freely in rotation inside the first nut around the axis.

[0018] The device according to the invention thus comprises three nuts. The intermediate piece is in fact an additional nut which is intended to be screwed onto one of the modules to be assembled, the first nut being intended to be screwed onto the other of the modules to be assembled.

[0019] The tightening or loosening of this intermediate nut is achieved by means of the main nut. When the intermediate nut is in its first axial position, simply turning the main nut is enough to rotate the intermediate nut. This is because the serrated edges of these nuts allow them to be locked together against rotation.

[0020] Once the intermediate nut has been tightened, particularly on the module to be assembled, it must then be rotated independently of the main nut so that the latter can rotate freely for tightening onto the other module to be assembled. This is done simply by positioning the intermediate nut in its second position.

[0021] It is therefore understood that the fastening device according to the invention is simpler to use than that of the prior art, in particular because it does not include added parts such as pins.

[0022] The present invention applies for example to the assembly of BP, HP or other body modules of a turbomachine.

[0023] The device according to the invention may comprise one or more of the following features, taken individually or in combination with each other: - the second serrated edge is located at an axial distance from the first annular stop face, and / or at an axial distance from the second thread; - the first serrated edge is located at an axial end of the intermediate nut, this axial end being located on the side of the first annular stop face; - the intermediate nut includes an internal annular rim which defines at least in part said third annular stop face and which further defines another annular stop face oriented on the opposite side to this third annular stop face; - the first crenellated rim and the internal annular rim are aligned in the same plane perpendicular to the axis; - the intermediate nut includes an annular row of holes which are oriented parallel to the axis and which open onto the side of the first thread; - the first nut includes an annular row of holes which are oriented parallel to the axis and which open onto the first annular stop face; - the device further includes a locking ring which is mounted around the first nut and which includes at least one axial finger engaged in one of the holes of the first nut and in one of the holes of the intermediate nut in order to lock them against rotation relative to each other around the axis; - the locking ring is engaged in an internal annular groove of the first nut and is axially blocked in this groove by axial stop on lateral walls of the groove; - the second nut includes an external annular rim which bears axially on a free end of the first nut and which defines another annular stop face oriented on the opposite side to the second annular stop face; - the first nut includes an annular row of blind holes which are oriented parallel to the axis and which open onto said free end; - the second nut includes an annular row of holes which are oriented parallel to the axis; - screws are screwed into the holes of the second nut and into the blind holes of the first nut in order to lock them against each other around the axis.

[0024] The present invention further relates to an assembly comprising two modules of a turbomachine and a device as described above, a first of the two modules comprising an external thread for screwing the intermediate nut, and a second of the modules comprising an external thread for screwing the first thread of the first nut.

[0025] The device or assembly according to the invention may comprise one or more of the following features, taken individually or in combination with each other: - the external thread is located at a free end of the first module; - the external thread is located on the tubular wall of the first module; - the internal annular rim of the intermediate nut bears axially on said free end of the first module; - the device is surrounded by a sealing system for the first module; - the sealing system is of the JRS type (segmented radial seal); - the first module is an HP or high pressure body of the turbomachine; - the second module is a BP or low pressure body of the turbomachine; - when the intermediate nut is in its first position, the second and fourth annular support faces cooperate with each other by axial stop; - when the intermediate nut is in its second position, the first and third annular bearing faces cooperate with each other by axial stop; - the axial distance between the first annular face of the stop and the serrated edge of the first nut is greater than an axial thickness or dimension of the serrated edge of the intermediate nut; - when the intermediate nut is in its second position, its serrated edge is axially interposed between the first annular stop face and the serrated edge of the first nut; - the axial distance between the serrated edge of the first nut and the second annular stop face of the second nut is less than an axial length or dimension of the intermediate nut.

[0026] The present invention further relates to a method of assembling an assembly as described above, comprising the following steps:

[0027] - assembly of the device by axially mounting the intermediate nut in the first nut, then screw the second nut into the first nut,

[0028] - screwing the intermediate nut onto the first module, the intermediate nut being in said first position,

[0029] - axial displacement of the first nut relative to the intermediate nut so that that the intermediate nut is in its second position,

[0030] - screwing the first nut onto the second module.

[0031] The method may further include a step of mounting the locking ring on the first nut so that the intermediate nut and the first nut are rotationally locked together. Brief description of the figures

[0032] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:

[0033] [Fig.1] Fig.1 is a partial schematic axial cross-sectional view of two turbomachine modules being assembled by a fastening device; [Fig.2] The [Fig.2] is a partial schematic axial cross-sectional view of a turbomachine module comprising a fastening device according to the invention; [Fig.3] The [Fig.3] is a larger scale view of the fastening device of the [Fig.2];

[0034] [Fig.4] Fig.4 is a schematic cross-sectional and perspective view of the device of fixing the [Fig.2], and illustrates a step in mounting the device on the turbomachine module;

[0035] [Fig.5] Fig.5 is a schematic cross-sectional and perspective view of the nut intermediate of the fastening device of the [Fig.2];

[0036] [Fig.6] Fig.6 is a schematic cross-sectional and perspective view of the nut main of the fastening device of the [Fig.2];

[0037] [Fig.7] Fig.7 is a schematic cross-sectional and perspective view of the nut retention of the fastening device of the [Fig.2];

[0038] [Fig. 8-9] Figures 8 and 9 are schematic cross-sectional and perspective views of the fastening device of the [Fig.2];

[0039] [Fig. 10] The [Fig. 10] is a schematic cross-sectional and perspective view of the fastening device of the [Fig.2], and illustrates a step in mounting the device and a first axial position of the intermediate nut vis-à-vis the main nut;

[0040] [Fig. 11] The [Fig. 11] is a view similar to that of the [Fig.1], and illustrates a step in the assembly of the device and a second axial position of the intermediate nut vis-à-vis the main nut;

[0041] [Fig. 12] The [Fig. 12] is a schematic cross-sectional and perspective view of the fastening device of the [Fig.2], and illustrates another step in mounting and locking the device by means of a locking ring;

[0042] [Fig. 13] Fig. 13 is a partial schematic perspective view of the locking ring; and

[0043] [Fig. 14] The [Fig. 14] is a partial schematic perspective view of the cooperation of the locking ring with the main nut and the intermediate nut of the device. Detailed description of the invention

[0044] Fig. 1 has been described above but can be used to illustrate the invention.

[0045] Figures 2 and 3 represent a module which is equipped with a fastening device 40 according to the invention.

[0046] In the example shown, the module is similar to module 10 of [Fig. 1], although it is only partially shown in the drawings. Module 10 comprises an intermediate housing 18, the preceding description of which can be used in the context of the present invention.

[0047] By way of non-limiting example, module 10 includes a shaft 42 or a section which must be fixed and rotationally secured to another element such as section 34 of module 12 of [Fig.1].

[0048] The shaft 42 can be the drive shaft of the blower 14 and of the rotor of the low pressure compressor 16 of the [Fig.1].

[0049] In the example shown, a bearing 44 is radially interposed between the shaft 42 and the inner periphery of the intermediate housing 18 in order to guide it in rotation around the axis A which is the longitudinal axis of the turbomachine.

[0050] Sealing systems 46, 48 are radially interposed between the shaft 42 and the inner periphery of the intermediate housing 18, respectively upstream and downstream of the bearing 44, in order to define an oil enclosure in which the bearing 44 is housed.

[0051] In the example shown, the upstream sealing system 46 is of the JRS type (segmented radial seal), and the downstream sealing system 48 is of the labyrinth type.

[0052] The shaft 42 includes a free end 42a, here upstream, which is surrounded by the sealing system 46 and on which the fastening device 40 according to the invention is intended to be mounted. It is therefore understood that the accessibility of the device 40 and of the end 42a is restricted because the environment is relatively cluttered.

[0053] The fastening device 40 is more clearly visible in figures 4 to 6 and following, which illustrate a preferred but not limiting embodiment.

[0054] The fastening device 40 comprises three elements and in particular three nuts 50, 52 and 54.

[0055] A first nut 50, called the main nut, comprises a first internal thread 56 having a first diameter D1, and a second internal thread 58 having a second diameter D2 ([Fig. 4]). D2 is greater than DL

[0056] The threads 56, 58 extend around the axis A and are axially separated from each other by a first annular stop face 60 which extends perpendicularly to the axis A and which is oriented towards the second thread 58.

[0057] As will be described in detail below, the first thread 56 is intended to cooperate by screwing with a corresponding thread of one of the modules to be assembled, and in particular module 12 in the example of [Fig.1].

[0058] A second nut 52, called a retaining nut, includes an external thread 62 suitable for cooperating with the second thread 58 of the first nut 50.

[0059] This second nut 52 has a second annular stop face 64 which extends perpendicularly to the axis A and which is oriented towards the first thread 56.

[0060] It is therefore understood that the second thread 58 of the first nut 50 is intended to cooperate by screwing with the thread 62 of the second nut 52.

[0061] An intermediate nut 54 is mounted inside the first nut 50 and axially interposed between the first and second threads 56, 58.

[0062] This intermediate nut 54 includes an internal thread 66 having a third diameter D3 between the first and second diameters Dl, D2.

[0063] As will be described in detail below, this thread 66 is intended to cooperate by screwing with a corresponding thread 68 of one of the modules to be assembled, and in particular with a thread 68 of the free end 42a of the shaft 42 of the module of figures 2 to 4 or with a thread of the shaft 24 of the module 10 of [Fig.1].

[0064] In general, the solution can be applied to assemble a BP shaft or an HP shaft. In the present case, it is used to assemble an HP shaft.

[0065] The intermediate nut 54 has third and fourth annular stop faces 70, 72 which extend perpendicularly to the axis A and which are located respectively opposite the first and second annular stop faces 60, 64.

[0066] Furthermore, the intermediate nut 54 includes an external annular rim 74 which is crenellated.

[0067] The first nut 50 also includes an internal annular rim 76 which is serrated and which is located between the first annular stop face 60 and the second thread 58.

[0068] We will now describe in more detail the different parts and their mutual cooperation.

[0069] The intermediate nut 54, more clearly visible in [Fig.5], includes the external ring rim 74 which is crenellated, that is to say, it includes an alternation of hollow parts 74a and solid parts 74b distributed around the axis A.

[0070] The serrated rim 74 is located at an axial end of the intermediate nut 54, this axial end 74 being located on the side of the first annular face of the stop 70.

[0071] In the example shown, the intermediate nut 54 further includes an internal annular rim 78 which defines at least in part this third annular stop face 70 and which further defines another annular stop face 80 oriented on the opposite side to this third annular stop face 70.

[0072] The crenellated rim 74 and the internal annular rim 78 are preferably aligned in the same plane perpendicular to the axis A.

[0073] In the example shown, the intermediate nut 54 further includes an annular row of orifices 82 which are oriented parallel to the axis A and which open on the side of the first thread 56 onto the stop face 70.

[0074] The first nut 50 is more clearly visible in [Fig.6] and its internal ring rim 76 with serrations also includes an alternation of hollow parts 76a and solid parts 76b distributed around the axis A.

[0075] This serrated rim 76 is preferably located at an axial distance DI from the first annular stop face 60 and at an axial distance D2 from the second thread 58.

[0076] The first nut 50 includes an annular row of blind holes 84 which are oriented parallel to the axis and which open onto the free end 50a of the first nut 50, on the side of its thread 58.

[0077] The first nut 50 further includes an annular row of holes 86 which are oriented parallel to the axis A and which open onto the first annular stop face 60.

[0078] The second nut 52, more clearly visible in [Fig.7], includes an external annular rim 88 which is intended to bear axially on the free end 50a of the first nut 50 and which defines another annular stop face 89 oriented on the opposite side to the second annular stop face 64.

[0079] In the example shown, the second nut 52 and in particular its rim 88 includes an annular row of holes 91 which are oriented parallel to the axis A.

[0080] Fig. 8 shows the nuts 50, 54 and allows the blind holes 84 to be seen on the free end 50a of the nut 50. This figure further shows that the serrated edges 74, 76 are able to cooperate together by dog-clutching, the solid parts of one of the edges 74, 76 being able to pass axially through the hollow parts of the other of the edges, and vice versa, in order to be able to move the nut 54 axially in the nut 50 by passing through the edge 76 of the nut 50.

[0081] Figure 9 shows the nuts 50, 52, and 54, and allows us to see the holes 91 of the nut 52 as well as the axial support of the rim 88 of this nut 52 on the axial end 50a of the nut 50. The holes 91 are designed to be axially aligned with the blind holes 84 so that screws 91' can be inserted into them. These screws 91' are screwed into the holes 91 and the blind holes 84 in order to lock the nuts 50 and 52 against each other about the axis A.

[0082] Figures 10 and 11 show two possible axial positions for the intermediate nut 54 in the first nut 50.

[0083] Indeed, when the second nut 52 is screwed into the first nut 50, the intermediate nut 54 remains axially mobile between the annular abutment faces 60, 64, in particular between a first position illustrated in [Fig. 10] in which the serrated edges 74, 76 are axially engaged with each other and cooperate by means of abutment in a circumferential direction, and a second axial position illustrated in [Fig. 11] in which the serrated edges 74, 76 are axially disengaged from each other. on the other so that the intermediate nut 54 can move freely in rotation inside the first nut 50 around the axis A.

[0084] In the position of [Fig. 10], the intermediate nut 54 is axially supported by its butt face 72 on the butt face 64 of the second nut 52. To achieve this result, it is preferable that the distance D2 be close to the length L1 of the intermediate nut 54 measured from its free end intended to axially support the butt face 64 to its butt face 80 intended to axially support the free end of the thread 68.

[0085] In the position of [Fig. 10], the intermediate nut 54 is rotationally fixed to the first nut 50 around the axis A. It is therefore understood that rotating this first nut 50 allows the intermediate nut 54 to be rotated and thus to be screwed or unscrewed onto the thread 68.

[0086] To prevent the nut 54 from moving axially inside the nut 50 when screwing the nut 54, it is possible to insert a shim (not shown), for example annular, between the stop faces 60, 70.

[0087] In the position of [Fig. 11], the first nut 50 is moved axially, here downstream, so that the external rim 74 of the intermediate nut 54 is interposed axially between the stop face 60 and the internal rim 76. To achieve this result, it is preferable that the thickness El of the external rim 74 be less than the distance Dl.

[0088] The nut 54 can come into axial support by its stop face 70 on the stop face 60 of the first nut 50.

[0089] The nut 52 can bear axially by its stop face 89 on a bearing surface of the aforementioned sealing system 46.

[0090] In the position of [Fig. 11], the first nut can move freely in rotation outside the intermediate nut 54 around the axis A. It is therefore understood that, in this position, the first nut 50 can be screwed without risk of unscrewing the intermediate nut 54.

[0091] Figures 12 to 14 show a locking ring 90 which the module according to the invention can include to prevent accidental unscrewing of the first nut 50 in operation.

[0092] The locking ring 90 is mounted around the first nut 50 and includes at least one axial finger 92 engaged in one of the orifices 86 of the first nut 50 and in one of the orifices 82 of the intermediate nut 54 in order to lock them against rotation relative to each other around the axis A.

[0093] The locking ring 90 is engaged in an internal annular groove 94 of the first nut 50 and is axially locked in this groove 94 by axial stop against the lateral walls of the groove 94. To facilitate the assembly of the locking ring 90 In this groove 94, it can be split to deform it and reduce its diameter during assembly. The locking ring 90 then returns to its default diameter by elastic recoil or may remain radially constrained at the bottom of the groove 94.

[0094] Alternatively, a nut brake could be used instead of the locking ring 90.

[0095] The invention further relates to an assembly comprising two modules 10, 12 of a turbomachine and a device 40 as described above.

[0096] The first module 10 may be similar to that of [Fig.1] and include an external thread 68 for screwing the intermediate nut 54, and a second module 12 may be similar to that of [Fig.1] and include an external thread for screwing the first thread 56 of the first nut 50.

[0097] The present invention further relates to a method for assembling this type of assembly, the method comprising the following steps:

[0098] - assembly of the device 40 by axially mounting the intermediate nut 54 in the first nut 50 then by screwing the second nut 52 into the first nut 50 (step a),

[0099] - screwing the intermediate nut 54 onto the first module 10, the intermediate nut 54 being in the first position mentioned above illustrated in [Fig. 10] (step b); figures 4 and 12 in particular illustrate this step,

[0100] - axial displacement of the first nut 50 vis-à-vis the intermediate nut 54 of so that the intermediate nut 54 is in its second position illustrated in [Fig. 1 1] (step c), and

[0101] - screwing the first nut 50 onto the second module 12.

[0102] In step a), the second nut 52 is screwed into the first nut 50 until its flange 88 bears axially against the free end 50a of the nut 50. The screws 91' are screwed into the holes 91 and the blind holes 84 of the nuts 52, 50 to prevent them from rotating relative to each other. The intermediate nut 54 remains axially movable between the first and second annular stop faces 60, 64.

[0103] Once assembled, the device 40 is presented on the first module 12 in step b) and the intermediate nut 54 is screwed onto the module 10 until the rim 78 of the nut 54 bears axially by its face 80 on the free end of the thread 68. The rotation of the nut 54 is achieved by means of the nut 50 and cooperation of the serrated rims 74, 76 in the circumferential direction.

[0104] After moving the nut 50 into its second position in step c), it is screwed onto the second module 12 in step d). With the nut 50 axially locked, it is the module 12 that translates upstream during tightening.

[0105] The locking ring 90 is then mounted in the groove 94 and the fingers 92 of this ring are engaged in the orifices 86, 82 to prevent the nuts 50, 54 from rotating against each other.

[0106] During disassembly of modules 10, 12, nut 50 will be unscrewed and module 12 will move back relative to module 10, which will prevent the serrated edges 74, 76 from colliding.

[0107] Preferably, the pitches of the threads 50, 66 of the nuts 50, 54 are different, or even these threads are reversed.

Claims

1. Demands Device (40) for fixing turbomachine modules (10, 12), this device (40) comprising: - a first nut (50), called the main nut, which includes a first internal thread (56) having a first diameter (Dl), and a second internal thread (58) having a second diameter (D2) greater than the first diameter (Dl), the first and second threads (56, 58) extending around the same axis (A) and being axially separated from each other by a first annular stop face (60) which extends perpendicularly to the axis (A) and which is oriented towards the second thread (58), - a second nut (52), called a retaining nut, which includes an external thread (62) adapted to cooperate with the second thread (58) of the first nut (50), this second nut (52) having a second annular stop face (64) which extends perpendicularly to the axis (A) and which is oriented towards the first thread (56), and - an intermediate annular piece mounted inside the first nut (50) and axially interposed between the first and second threads (56, 58), this intermediate piece having third and fourth annular stop faces (70, 72) which extend perpendicularly to the axis (A) and which are located respectively opposite the first and second annular stop faces (60, 64), characterized in that the intermediate piece, called intermediate nut (54), includes an internal thread (56) having a third diameter (D3) included between the first and second diameters (D1, D2), in that the intermediate nut (54) comprises an external annular rim (74) which is serrated, and the first nut (50) comprises an internal annular rim (76) which is serrated and which is located between the first annular stop face (60) and the second thread (58), and in that, when the second nut (52) is screwed into the first nut (50), the intermediate nut (54) remains axially movable between the first and second annular stop faces (60, 64), in particular between a first position in which the serrated rims (74, 76) are axially engaged with each other and cooperate by means of a stop in a circumferential direction with each other so that the intermediate nut (54) is rotationally fixed to the first nut (50) around the axis (A), and a second axial position in which the serrated edges (74, 76) are axially disengaged from each other so that the intermediate nut (54) can move freely in rotation inside the first nut (50) around the axis (A).

2. Device (40) according to claim 1, wherein the second serrated rim (76) is located at an axial distance (D1) from the first annular stop face (60), and / or at an axial distance (D2) from the second thread (58).

3. Device (40) according to claim 1 or 2, wherein the first serrated rim (74) is located at an axial end of the intermediate nut (54), this axial end being located on the side of the first annular stop face (60).

4. Device (40) according to any one of the preceding claims, wherein the intermediate nut (54) comprises an internal annular rim (78) which defines at least in part said third annular stop face (70) and which further defines another annular stop face (80) oriented on the opposite side to this third annular stop face (70).

5. Device (40) according to claims 3 and 4, wherein the first serrated rim (74) and the internal annular rim (78) are aligned in the same plane perpendicular to the axis (A).

6. Device (40) according to any one of the preceding claims, wherein the intermediate nut (54) comprises an annular row of orifices (82) which are oriented parallel to the axis (A) and which open out on the side of the first thread (56).

7. Device (40) according to any one of the preceding claims, wherein the first nut (50) comprises an annular row of orifices (86) which are oriented parallel to the axis (A) and which open onto the first annular stop face (60).

8. Device (40) according to all claims 6 and 7, wherein it further comprises a locking ring (90) which is mounted around the first nut (50) and which comprises at least one axial finger (92) engaged in one of the orifices (86) of the first nut (50) and in one of the orifices (82) of the intermediate nut (54) in order to lock them against rotation relative to each other about the axis (A).

9. Device (40) according to claim 8, wherein the locking ring (90) is engaged in an internal annular groove (94) of the first nut (50) and is axially locked in this groove (94) by axial stop on lateral walls of the groove (94).

10. Device (40) according to any one of the preceding claims, wherein the second nut (52) comprises an external annular rim (88) which bears axially on a free end of the first nut (50) and which defines another annular stop face (89) oriented on the opposite side to the second annular stop face (64).

11. Device (40) according to claim 10, wherein the first nut (50) comprises an annular row of blind holes (84) which are oriented parallel to the axis (A) and which open onto said free end.

12. Device (40) according to any one of the preceding claims, wherein the second nut (52) comprises an annular row of orifices (91) which are oriented parallel to the axis (A).

13. Device (40) according to all claims 11 and 12, in which screws (91') are screwed into the orifices (91) of the second nut (52) and into the blind holes (84) of the first nut (50) in order to lock them against rotation relative to each other around the axis (A).

14. Assembly comprising two modules (10, 12) of a turbomachine and a device (40) according to any one of the preceding claims, a first of the two modules (10) comprising an external thread for screwing the intermediate nut (54), and a second of the modules (12) comprising an external thread for screwing the first thread (56) of the first nut (50).

15. Method of assembling an assembly according to the preceding claim, comprising the following steps: - assembly of the device (40) by axially mounting the intermediate nut (54) in the first nut (50) and then screwing the second nut (52) into the first nut (50), - screwing the intermediate nut (54) onto the first module (10), the intermediate nut (54) being in said first position, - axial displacement of the first nut (50) vis-à-vis the intermediate nut (54) so ​​that the intermediate nut (54) is in its second position, - screwing the first nut (50) onto the second module (12).

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