TURBOMACHINE COMPRISING SEVERAL MODULES AND A DEVICE FOR LOCKING THESE MODULES, AND CORRESPONDING ASSEMBLY METHOD

Abstract

The invention relates to an aircraft turbomachine comprising: - a first module (14) comprising a compressor (4) and a low-pressure shaft (15), - a second module (16) comprising a turbine (8) and a low-pressure shaft (17), the low-pressure turbine shaft comprising a downstream end connected to a rotor of the turbine and an upstream end (17a) connected to a rotor of the compressor, and - a locking device configured so as to axially immobilize the low-pressure turbine shaft (17) relative to the low-pressure compressor shaft (15), in which the locking device (50) comprises a nut (52) and an intermediate part (80), each centered on the longitudinal axis, the nut being screwed onto a thread of the intermediate part, and the intermediate part cooperating with the upstream end of the low-pressure turbine shaft and the nut bearing against an annular projection (60) of the first module (14). Figure for abstract: Figure 17

Description

Title of the invention: TURBOMACHINE COMPRISING SEVERAL MODULES AND A DEVICE FOR LOCKING THEM THESE MODULES, AND CORRESPONDING MOUNTING METHOD Technical field

[0001] The present invention relates to solutions for facilitating the modularity of an aircraft turbomachine. Prior art

[0002] An aircraft turbomachine is often produced in the form of an assembly of modules that may each include fixed and moving parts. A module is defined as a subassembly of an engine that has geometric characteristics at its interfaces with adjacent modules that are sufficiently precise for it to be delivered individually, and which has undergone separate balancing when it includes rotating parts. Assembling the modules makes it possible to form a complete engine, minimizing the balancing and matching operations of the interface parts.

[0003] The modularity of a turbomachine is a key element for its maintenance. Indeed, during an intervention, the parts must be easily accessible without having to dismantle a large number of parts of the engine. In practice, we try to obtain a division into a few major and minor modules. For example, for a turbomachine having an upstream fan (the terms "upstream" and "downstream" are assessed in relation to the flow of gases in the turbomachine), it is configured with three major modules: an upstream major module for the front part including the fan, an intermediate major module for the intermediate part including the low pressure compressor and the high pressure body and a downstream major module for the rear part including the low pressure turbine and the low pressure shaft. In this specific example, the low pressure body is divided into two modules.It is possible that the low pressure body is divided equally into three modules with the low pressure compressor arranged independently of the rest of the intermediate major module.

[0004] Generally, the major intermediate module and the major downstream module comprising the members of the low-pressure body are fixed to each other by means of a nut which is centered on the axis of the turbomachine and which serves to axially tighten the low-pressure compressor shaft and the low-pressure turbine shaft. During a maintenance operation, this nut must be unscrewed using a tool which is inserted into the turbomachine along its longitudinal axis, and therefore inside the low pressure shaft.

[0005] This maintenance is particularly difficult on a turbomachine comprising a reducer in the front or upstream part and possibly a blade pitch change system upstream. The problem in this case is accessibility to the nut. The reducer is located upstream of the nut and must be partially dismantled to gain access to the nut. Furthermore, access to the nut is achieved with complex tools from upstream of the turbomachine to prevent them from being too long and to have an acceptable diameter.

[0006] The tools are inserted through the internal planetary gear of the speed reducer which, however, has an internal diameter generally smaller than the diameter of the nut (for example of the order of 60 mm). Indeed, it is generally not possible to dismantle the speed reducer without disassembling a large part of the turbomachine including the major downstream module.

[0007] This implies on the one hand that the access diameter of the tools is smaller than that of the nut and on the other hand that the nut is trapped in the turbomachine. Increasing the internal diameter of the internal planetary gear to be greater than that of the nut and allow the nut to be removed would be detrimental to the size of the reducer and the general performance of the turbomachine.

[0008] Furthermore, the tools may present risks of incorrect handling and damage to certain parts of the turbomachine which are located near the nut. Added to this is the fact that the nut also requires a high tightening torque (order of magnitude 2000 Nm). With such a torque, a long and small diameter wrench has the disadvantage of having a high torsion angle and consequently poor precision in finding an exact angular position necessary to access the nut, all this while blind.

[0009] In order to improve their propulsive efficiency, turbomachines tend towards increasing the bypass ratios, which generally results in an increase in the size of the fan (diameter and axial dimension). This makes access to the low pressure shaft nut even more complex due to the lengthening of the tool required to access it.

[0010] Furthermore, certain turbomachines, such as those with a single unducted fan (also called USF, acronym for Unducted Single Fan), have a particularly long length and the modules of the high pressure and low pressure bodies have very small internal diameters, which complicates or even makes access to the nut by the tool impossible.

[0011] The present invention provides a solution to at least part of the problems mentioned above which simplifies the modularity of an aircraft turbomachine and which does not penalize the efficiency of the turbomachine. Summary of the invention

[0012] For this purpose, the invention relates to an aircraft turbomachine, the turbomachine having a longitudinal axis and comprising: - a first module comprising a low pressure compressor and a low pressure compressor shaft which is centered on the longitudinal axis, - a second module comprising a low pressure turbine and a low pressure turbine shaft which is centered on the longitudinal axis, the low pressure turbine shaft comprising a downstream end connected to a rotor of the low pressure turbine and an upstream end connected to a rotor of the low pressure compressor, and - a locking device configured so as to axially immobilize the low pressure turbine shaft of the second module relative to the low pressure compressor shaft of the first module. According to the invention, the locking device comprises a nut and an intermediate part, each centered on the longitudinal axis, the nut being screwed onto a thread of the intermediate part, and the intermediate part cooperating with the upstream end of the low-pressure turbine shaft and the nut bearing against an annular projection of the first module.

[0013] Thus, this solution makes it possible to achieve the aforementioned objective. In particular, the intermediate piece forms a nut riser making it possible to increase the implantation radius of the nut. Indeed, the intermediate piece makes it possible to have a thread with a higher radius, and therefore with better capacity and mechanical strength of the nut during tightening. This intermediate piece advantageously makes it possible to take up the axial force and the tightening force of the torque.

[0014] This configuration provides increased modularity. The arrangement of the intermediate piece and the nut allows for effective immobilization between the modules. This also allows at least one non-bulky tool to be brought inside. The low-pressure turbine module and the low-pressure compressor can thus be dismantled in a reduced number of operations compared to the other modules and without dismantling the other adjacent modules. The intermediate piece provides sufficient clamping force, even for small low-pressure shaft diameters.

[0015] This modularity is part of an approach to reducing environmental impact since it allows only the necessary components to be repaired and checked and reduces the downtime of the turbomachine.

[0016] The turbomachine according to the invention may comprise one or more of the characteristics following characteristics, taken individually or in combination with each other in all technically possible combinations: - the low-pressure turbine shaft comprises external splines oriented parallel to the longitudinal axis and the intermediate part comprises internal splines complementary to said external splines, the intermediate part being axially engaged on the low-pressure turbine shaft so that the intermediate part and the low-pressure turbine shaft are integral in rotation by engagement of their splines; - the axial locking device comprises an additional axial locking system configured to axially immobilize the intermediate part relative to the low pressure turbine shaft; - the additional axial locking system comprises at least one annular row of radial teeth arranged on the intermediate part and configured to cooperate by dog ​​engagement with an annular row of radial slots of the low pressure turbine shaft; - the locking device comprises a ring centered on the longitudinal axis and received in an annular groove formed in the intermediate part upstream of the at least one annular row of radial teeth; - the locking device comprises a rotation locking system configured to hold the nut in position against the projection; - the rotation locking system comprises: a first ring centered on the longitudinal axis and intended to bear against a radial annular face of the nut, the first ring comprising at least one radial tooth each intended to engage in a radial notch of the intermediate part, and a second ring, centered on the longitudinal axis and received in an annular groove of the nut, the annular groove being provided upstream of the radial annular face; - the upstream end of the low pressure turbine shaft extends inside the low pressure compressor shaft, the nut and the intermediate piece being mounted inside the low pressure compressor shaft which includes the shoulder, the intermediate piece being arranged radially between the nut and the upstream end; - the turbomachine comprises a fan which is connected to a fan shaft and which is arranged upstream of the first module and the low-pressure compressor, a low-pressure shaft driving the fan shaft in rotation via a speed reducer, the low-pressure shaft being formed by the connection of the low-pressure compressor shaft with the low-pressure turbine shaft; - the low pressure compressor shaft is connected to an input shaft of the speed reducer.

[0017] The invention also relates to a method of mounting a turbomachine. aircraft according to the invention and as described above, the method comprises the steps of: - installation of the intermediate part on the upstream end of the low pressure turbine shaft from upstream to downstream; - axial immobilization of the intermediate part relative to the low pressure turbine shaft; - screwing the nut onto the intermediate piece; and - locking the nut in rotation.

[0018] The method according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another in all technically possible combinations: - the nut is pre-assembled to the intermediate piece by screwing before installing the intermediate piece on the low pressure turbine shaft; - the assembly process includes axial locking of the intermediate part before tightening the nut. Brief description of the drawings

[0019] The present invention will be better understood and other details, characteristics and advantages of the present invention will appear more clearly on reading the description of a non-limiting example which follows, with reference to the appended drawings in which: - [Fig.l] is a schematic half-view in axial section of an aircraft turbomachine; - [Fig.2] is an enlarged schematic sectional view of the turbomachine of [Fig.l] at the connection between a low-pressure compressor shaft and a low-pressure turbine shaft according to the technique prior to the invention; - [Fig.3] represents a schematic view of the forces dimensioning the connection between the low pressure compressor shaft and the low pressure turbine shaft according to the technique prior to the invention; - [Fig.4] is an enlarged schematic sectional view of the turbomachine of [Fig.l] at the connection between a low-pressure compressor shaft and a low-pressure turbine shaft according to the invention; - [Fig.5] is a schematic perspective view in axial section of an intermediate part forming a nut extension of the connection illustrated in [Fig.4]; - [Fig.6] is a schematic perspective and axial sectional view of the upstream end of the low pressure turbine shaft of the connection illustrated in [Fig.4]; - [Fig.7] is a schematic perspective view of an anti-rotation device installed on the intermediate part of [Fig.5] and a nut of the connection illustrated in [Fig.4] ; - [Fig.8] is a schematic perspective and axial sectional view of the connection illustrated in [Fig.4]; - [Fig.9] is the forces dimensioning the connection between the low pressure compressor shaft and the low pressure turbine shaft according to the invention; - [Fig. 10] is a schematic perspective and axial sectional view of the method of mounting the connection of [Fig.4] illustrating a step of approaching the intermediate part of [Fig.5]; - [Fig. 11] is a view similar to [Fig. 10] showing a step of shifting towards the downstream position of the intermediate part of [Fig.5]; - [Fig. 12] is a schematic perspective and axial sectional view of the method of mounting the connection of [Fig.4] illustrating a step of angular positioning of the intermediate part of [Fig.5]; - [Fig. 13] is a view similar to [Fig. 10] showing a step of axial positioning of the intermediate part of [Fig.5]; - [Fig. 14] is a view similar to [Fig. 10] illustrating an optional step of installing an axial locking system for the intermediate part of [Fig. 11]; - [Fig. 15] is a view similar to [Fig. 10] showing a step of tightening a nut of the connection illustrated in [Fig.4]; - [Fig. 16] is a view similar to [Fig. 10] illustrating a step in installing an anti-rotation system; - [Fig. 17] is a view similar to [Fig. 10] showing a step of installing an axial brake blocking the anti-rotation system; - [Fig. 18] represents a schematic perspective view of the upstream end of the low pressure turbine shaft of the connection illustrated in [Fig. 4] according to another embodiment; and - [Fig. 19] is an enlarged schematic perspective and sectional view of the turbomachine of [Fig.l] at the level of the connection between a low pressure compressor shaft and the low pressure turbine shaft of [Fig.18] according to the other embodiment of the invention.

[0020] Elements having the same functions in different implementations have the same references in the figures.

[0021] In the figures, the scales and proportions are not strictly respected, for the purposes of illustration and clarity.

[0022] In the description, the expressions “internal” or “interior” and “external” or “exterior” are used without limitation in reference to the radial distance from the longitudinal axis around which the turbomachine extends, the expression “internal” defining a zone radially closer to the longitudinal axis of the nacelle, as opposed to the expression “external”. Furthermore, in the description and the claims, the terminology axial, radial and transverse will be adopted without limitation with reference to the trihedron A, R, T indicated in the figures, the axial axis A being parallel to the longitudinal axis of the turbomachine. Description of the embodiments

[0023] Reference is first made to [Fig. 1] which illustrates an aircraft turbomachine which is here a single unducted fan (USF) turbomachine 1 although the aspects of the invention are not limited to this particular type of turbomachine.

[0024] The turbomachine has a longitudinal axis denoted C, which is generally the axis of rotation of its rotors, around which its various components extend. It comprises from upstream to downstream: a fan 2, a low-pressure compressor 4, a high-pressure compressor 5, an annular combustion chamber 6, a high-pressure turbine 7 and a low-pressure turbine 8.

[0025] In the present invention, and generally, the terms "upstream" and "downstream" are defined with respect to a main direction F of circulation of the fluids inside the turbomachine, and here along the longitudinal axis C, that is to say from left to right with reference to [Fig.l].

[0026] The low pressure compressor 4 and the low pressure turbine 8 are mechanically connected by a low pressure shaft 9 so as to form a low pressure body. The high pressure compressor 5 and the high pressure turbine 7 are mechanically connected by a high pressure shaft 10 so as to form a high pressure body.

[0027] The turbomachine 1 is modular and comprises several modules assembled / connected to each other and which make it easier to maintain it. Shafts and / or interfaces make it possible to make these connections.

[0028] A first module 14 comprises the low pressure compressor 4 and a low pressure compressor shaft 15.

[0029] A second module 16 comprises the low-pressure turbine 8 and a low-pressure turbine shaft 17 which is centered on the longitudinal axis C. The low-pressure turbine shaft 17 advantageously comprises an upstream end 17a connected to a rotor of the low-pressure compressor 4, and in particular to the low-pressure compressor shaft 15, and a downstream end connected to a low-pressure turbine rotor 8. In operation, the low-pressure compressor shaft 15 is rotationally integral with the low-pressure turbine shaft 17 to form the low-pressure shaft 9.

[0030] A third module 18 or high pressure or HP module comprises the high pressure compressor 5 and the high pressure turbine 7 whose rotors are connected by the high pressure shaft 10 and form the high pressure body. The third module 18 also comprises the annular combustion chamber 6 which is interposed axially between the high pressure compressor 5 and the high pressure turbine 7.

[0031] The turbomachine further comprises an upstream module 11 which comprises the fan 2 and a speed reducer 3. The latter comprises an input shaft which is centered on the longitudinal axis C. The input shaft is part of the upstream module 11. The fan 2 comprises a fan shaft 13 which is driven in rotation by the low pressure shaft 9 via the speed reducer 3. The upstream module 11 is mounted upstream of the first module 14.

[0032] The low pressure compressor shaft 15 and the input shaft 12 are both advantageously hollow. The low pressure shaft 9 is also hollow.

[0033] The low pressure shaft 9 extends at least partly inside the high pressure shaft 10 and are coaxial.

[0034] According to this configuration, the low pressure body or LP of the turbomachine 1 is divided into three modules. Alternatively, the low pressure body is divided into two modules with the low pressure compressor 4 forming part of the first module 14.

[0035] The turbomachine 1 is in fact equipped with a speed reducer 3 (known by the English acronym RGB) which advantageously comprises an epicyclic gear train. Of course, the speed reducer could comprise a planetary type gear. A reducer with an epicyclic gear train conventionally comprises a sun gear (or internal planetary gear), a plurality of satellites (which are pinions), a planet carrier and an external ring gear (or external planetary gear). The sun gear is centered on the longitudinal axis C. The external ring gear is centered on the longitudinal axis C and extends around the sun gear. The satellites are arranged between the sun gear and the external ring gear and are carried by the planet carrier. The satellites are each mounted to rotate freely around a satellite axis using a bearing and mesh with external teeth of the sun gear and internal teeth of the external ring gear.

[0036] In the present case, the external crown is stationary and fixed to a stator of the turbomachine which is here an input casing 24. The solar is mobile in rotation and coupled to the input shaft which itself is connected to the low pressure shaft 9. The planet carrier is also mobile in rotation and coupled to the fan shaft 13. The fan 2 is therefore driven in rotation by the low pressure shaft 9 via the reducer 3.

[0037] In the case of a planetary type gear reducer, the external crown is integral in rotation with the fan shaft, the planet carrier is integral with a fixed structure such as the input casing 24.

[0038] The reducer 3 is arranged in a lubrication enclosure 25 which extends around the axis C and therefore has a generally annular shape. At its internal periphery, the enclosure 25 is delimited by the fan shaft 13 and the input shaft. At its external periphery, the enclosure 25 is advantageously, but not limited to, delimited by the input casing 24 which extends around the reducer 3. At its upstream end, the enclosure 25 is delimited by a bearing support, for example, which is annular. This support has an external periphery which is fixed to the input casing 24 and an internal periphery which holds rolling bearing races, the internal races of which are fixed to the fan shaft 13. Finally, the enclosure 25 is closed at its downstream end by an annular cover which is carried by the input casing 24 and the internal periphery of which surrounds the input shaft in a sealed manner.

[0039] The turbomachine 1 also comprises: - an intermediate casing 34 which is inserted between the low pressure compressor 4 and the high pressure compressor 5, - an inter-turbine casing 35 which is inserted between the high pressure turbine 7 and the low pressure turbine 8, and - an exhaust casing 36 which is located downstream of the low pressure turbine 8.

[0040] The low pressure compressor 4 and the high pressure module 18 are surrounded by an annular casing 38, an upstream end of which comprises an annular flange 38a for attachment to an annular flange 24b of the inlet casing 24, and a downstream end of which comprises an annular flange 38b for attachment to an annular flange 36a of the exhaust casing 36.

[0041] As indicated previously, trees and / or interfaces make it possible to create links between several modules.

[0042] In particular, the turbomachine 1 comprises coupling means 40 configured so as to connect the first module 14 and the second module 16. In particular, the low-pressure compressor shaft 15 is integral in rotation with the low-pressure turbine shaft 17 and is also immobilized axially relative to the low-pressure turbine shaft 17.

[0043] The low-pressure compressor shaft 15 is coupled to the low-pressure turbine shaft 17 by means of splines. The coupling means 40 are formed by the splines. In particular, the low-pressure turbine shaft 17 extends at least partly inside the low-pressure compressor shaft 15. The latter comprises a plurality of internal splines 49 which are oriented along the longitudinal axis. These internal splines 49 are arranged on an internal surface of the low-pressure compressor shaft 15 and regularly distributed around the longitudinal axis C. These are advantageously located at the downstream end 15b of the low-pressure compressor shaft 15.

[0044] These internal splines 49 are configured to engage with corresponding external splines 50 of the low pressure turbine shaft 17. The external splines 50 are arranged on an external surface of the low pressure turbine shaft 17 and towards its upstream end 17a. These internal and external splines 49, 50 allow the low pressure turbine shaft 17 to rotate the low pressure compressor shaft 15 and transmit the rotational torque.

[0045] The coupling means 40 further comprises an axial locking device configured so as to axially immobilize the second module 16 relative to the first module 14. More precisely, the locking device makes it possible to immobilize the low-pressure turbine shaft 17 relative to the low-pressure compressor shaft 15.

[0046] In the current technique and as shown in [Fig.2], such an axial locking device 50A comprises a nut 52A which is configured so as to axially immobilize the low pressure compressor shaft 15 relative to the low pressure turbine shaft 17 and to achieve the recovery of the axial thrust of the low pressure turbine. The nut 52A comprises an axis of revolution which is coaxial with the longitudinal axis C in the installation situation.

[0047] The nut 52A is screwed onto the low pressure turbine shaft 17 and is centered on the longitudinal axis C in the installation situation. The nut 52A is arranged radially between the low pressure compressor shaft 15 and the low pressure turbine shaft 17. The nut 52A comprises a thread which is screwed onto the second module 16. More specifically, the nut 52A comprises an internal thread 58A which engages with an external thread 59A of the low pressure turbine shaft 17. The external thread 59A is located at the upstream end 17a of the low pressure turbine shaft 17, and more precisely upstream of the external splines 50 of the low pressure turbine shaft 17.

[0048] The outer diameter of the nut 52A is less than the inner diameter of the low pressure compressor shaft 15 and greater than the outer diameter of the low pressure turbine shaft 17.

[0049] The nut 52A is engaged axially from upstream on the upstream end 17a of the low-pressure turbine shaft 17 and is screwed until it is axially tightened against an annular projection 60 or the like of the low-pressure shaft of the first module 14. In particular, the low-pressure compressor shaft 15 comprises this annular projection 60 which extends radially inwards, i.e. towards the longitudinal axis C. In the present example, the annular projection 60 is formed upstream of the internal and external splines 49, 50. The nut 52A comprises a downstream lateral face 53A, annular, coming to bear against an upstream annular surface 60a of the projection 60. The low-pressure turbine shaft 17 can no longer move backwards downstream, nor can the low-pressure turbine.

[0050] Furthermore, the turbomachine 1 advantageously comprises an annular adjustment shim 70, arranged between the annular projection 60 of the low-pressure compressor shaft 15 and an annular shoulder 72 of the low-pressure turbine shaft 17. In the present example, the annular shoulder 72 is formed upstream of the internal and external grooves 49, 50. The adjustment shim 70 comprises an upstream lateral face 70a, annular, coming to bear against a downstream annular surface 60b of the projection 60 and a downstream lateral face 70b, annular, coming to bear against an upstream annular surface 72a of the annular shoulder 72.

[0051] This axial adjustment shim 70 advantageously makes it possible to control or choose the position of the different elements of the connection.

[0052] Thus, in the current technique, the assembly of the low pressure shaft in the turbomachine comprises the passage of the low pressure turbine shaft 17, downstream, inside the high pressure body, then the assembly of the low pressure turbine shaft 17 with the rest of the engine by tightening the nut 52A upstream using a dedicated tool, the nut 52A being passed upstream to its position on the low pressure turbine shaft.

[0053] It is understood from this arrangement that the maximum integration diameter of the splines 50 of the shaft of the low pressure turbine 17 is limited by the size of the high pressure body, in order to allow the mounting of the low pressure shaft in the engine.

[0054] Similarly, upstream of these grooves 50, the integration diameter of the thread 58A of the nut 52A is limited by several elements, in particular: the integration diameter of the grooves 50, the adjustment shim 70 and the radial offsets necessary for the manufacture and assembly of the different elements.

[0055] It is therefore understood that all these points constrain and limit the possible diameter for the integration of this tightening nut 52A.

[0056] However, new generations of engines will tend, in order to save fuel, to reduce the size of the high-pressure body as much as possible, creating the need to reduce the diameter for the integration of the splines 49, 50, but also of the nut 52A of this connection.

[0057] However, the installation diameter of this connection plays a major role in its mechanical capacity to pass loads. Indeed, this nut and its tightening force must overcome the aerodynamic forces applied to the low-pressure turbine and the low-pressure compressor. [Fig. 3] illustrates the forces sizing this connection. The aerodynamic forces applied to the low-pressure turbine are represented by the arrow F1 and the aerodynamic forces applied to the low-pressure compressor, opposite those of the low-pressure turbine, are represented by the arrow F2. The tightening force of the nut to overcome the external axial forces is represented by the arrow F3.

[0058] The main problem that the invention seeks to solve is therefore to be able to increase the integration diameter of this nut. This is in fact the parameter which plays a first order role in the dimensioning of the nuts.

[0059] Indeed, even if the number of threads in engagement plays a role in the dimensioning of the nut since the load is distributed over the different threads in engagement at the cost of an increase in the axial size, there is a level because, from 4 or 5 threads in engagement, there is almost no further reduction in the force in the first thread of the nut.

[0060] The invention proposes a solution to facilitate the modularity of the turbomachine 1 thanks to a particular device for coupling the first module 14 and the second module 16 and in particular the low pressure compressor shaft 15 of the first module 14 to the low pressure turbine shaft 17 of the second module 16.

[0061] Figures 4 to 15 illustrate an embodiment of this device according to the invention in which the elements already described in the above are designated by the same references. In particular, [Fig.4] is an enlarged schematic sectional view of the turbomachine of [Fig.1] at the connection between the low-pressure compressor shaft 15 of the first module and the low-pressure turbine shaft 17 of the second module according to the invention. Figures 5 and 6 schematically represent parts of this connection and Figures 8 to 15 illustrate steps of the method of mounting this connection which will be described later. [Fig.9] illustrates the forces dimensioning this connection.

[0062] As described previously, the turbomachine 1 comprises coupling means 40 configured so as to connect the first module 14 and the second module 16. In particular, the low-pressure compressor shaft 15 is integral in rotation with the low-pressure turbine shaft 17 and is also immobilized axially relative to the low-pressure turbine shaft 17.

[0063] The low-pressure compressor shaft 15 is coupled to the low-pressure turbine shaft 17 by means of splines. The coupling means 40 are formed by the splines. In particular, the low-pressure turbine shaft 17 extends at least partly inside the low-pressure compressor shaft 15. The latter comprises a plurality of first internal splines 49 which are oriented along the longitudinal axis. These first internal splines 49 are arranged on an internal surface of the low-pressure compressor shaft 15 and regularly around the longitudinal axis C. These are advantageously located at the downstream end 15b of the low-pressure compressor shaft 15.

[0064] These first internal splines 49 are configured to engage with corresponding first external splines 50 of the low pressure turbine shaft 17. The first external splines 50 are arranged on an external surface of the low pressure turbine shaft 17 and towards its upstream end 17a. These first internal and external splines 49, 50 allow the low pressure turbine shaft 17 to rotate the low pressure compressor shaft 15 and the transmission of rotational torque.

[0065] The coupling means 40 further advantageously comprise an axial locking device configured so as to axially immobilize the second module 16 relative to the first module 14. More precisely, the locking device makes it possible to immobilize the low-pressure turbine shaft 17 relative to the low-pressure compressor shaft 15.

[0066] According to the invention and with reference to [Fig. 4], such an axial locking device 50 comprises an assembly 51 which is configured so as to axially immobilize the low-pressure compressor shaft 15 relative to the low-pressure turbine shaft 17 and to carry out the recovery of the axial thrust of the low-pressure turbine. The assembly 51 is formed of a nut 52 and an intermediate piece 80.

[0067] [Fig.5] is a schematic perspective and axial sectional view of the intermediate part 80 of this assembly and [Fig.6] is a schematic perspective and axial sectional view of the upstream end of the low pressure turbine shaft 17 of the connection.

[0068] The nut 52 comprises an axis of revolution which is coaxial with the longitudinal axis C in the installation situation. The nut 52 is arranged radially between the low-pressure compressor shaft 15 and the low-pressure turbine shaft 17. It is configured to cooperate with the low-pressure turbine shaft 17 via the intermediate part 80. In the present example, the nut 52 comprises an upstream portion 52a and a downstream portion 52b which are annular and extend along the axis of revolution.

[0069] The intermediate part 80 comprises an axis of revolution which is coaxial with the longitudinal axis C in the installation situation. The intermediate part 80 is arranged radially between the nut 52 and the low-pressure turbine shaft 17. In the present example, the intermediate part 80 comprises an upstream portion 80aa and a downstream portion 80bb which are annular and extend along the axis of revolution.

[0070] The nut 52 comprises a thread which is screwed onto the intermediate part 80. More precisely, the nut 52, and more precisely the downstream portion 52b, comprises an internal thread 58 which engages with an external thread 81 of the intermediate part 80. The external thread 81 is located at the downstream end 80b of the intermediate part 80 on the downstream portion 80bb.

[0071] The intermediate part 80 further comprises splines for coupling with the low-pressure turbine shaft 17. More precisely, the intermediate part 80 comprises a plurality of second internal splines 82 which are oriented along the longitudinal axis C. These second internal splines 82 are arranged on an internal surface of the intermediate part 80 and regularly distributed around the longitudinal axis C. These are advantageously located at the downstream end 80b of the intermediate part 80 on the downstream portion 80bb.

[0072] These second internal grooves 82 are configured to engage with corresponding second external splines 83 of the low pressure turbine shaft 17. The second external splines 83 are arranged on the external surface of the low pressure turbine shaft 17 and towards its upstream end 17a. The second external splines 83 are arranged upstream of the first external splines 50. The second internal and external grooves 82, 83 advantageously make it possible to take up the torque applied to the nut 52 during tightening for the assembly of the first module 14 to the second module 16.

[0073] The second internal and external grooves 82, 83 extend over a length L1 in the axial direction A less than the extension length L2 of the first second internal and external grooves 49, 50.

[0074] The second internal and external grooves 82, 83 extend over a length L1 in the axial direction A less than the extension length L3 (in the axial direction A) of the external thread 81 of the intermediate part 80.

[0075] In the illustrated example, the extension length L1 of the second internal and external splines 82, 83 is less than the extension length L2 of the first second internal and external splines 49, 50. Similarly, in the example, the extension length L1 of the second internal and external splines 82, 83 is less than the extension length L3 of the external thread 81 of the intermediate part 80. These length ratios make it possible to minimize the total size.

[0076] Alternatively, the extension length L1 of the second internal and external grooves 82, 83 may be greater than the extension length L2 of the first second internal and external grooves 49, 50.

[0077] In the example shown, the low-pressure compressor shaft 15 comprises a first shaft portion 15aa and a second shaft portion 15bb downstream of the first shaft portion 15aa. The first portion 15aa comprises an internal diameter DI which is greater than the internal diameter D2 of the second portion 15bb. The internal diameter DI of the first shaft portion 15aa is substantially greater than the external diameter of the low-pressure turbine shaft 17. The internal diameter D2 of the second portion 15bb is substantially equal to the external diameter of the low-pressure turbine shaft 17. The first internal splines 49 are arranged on the second portion 15bb of the low-pressure compressor shaft 15.

[0078] We can also see in [Fig.4] that the low-pressure turbine shaft 17 comprises, from upstream to downstream, a first shaft portion 17aa, a second shaft portion 17ab and a third shaft portion 17bb. The first portion 17aa comprises an external diameter D3 which is smaller than the external diameter D4 of the second portion 17ab. The external diameter D4 of the second portion 17ab is smaller than the external diameter D5 of the third portion 17bb. The diameter D5 corresponds to the diameter of the first external splines 50 and more precisely of the bottom of the first external grooves 50.

[0079] The internal diameter D2 of the second portion 15bb of the low pressure compressor shaft 15 is substantially equal to the external diameter D5 of the low pressure turbine shaft 17.

[0080] The first external splines 50 are arranged on the third portion 17bb while the second external splines 83 are arranged on the second portion 17ab of the low pressure turbine shaft 17.

[0081] The second external grooves 83, and more precisely the bottom of the second external grooves 83, have a diameter D7 less than the external diameter D4 of the second portion 17ab.

[0082] The external diameter of the nut 52 is less than the internal diameter of the low-pressure compressor shaft 15 and greater than the external diameter of the low-pressure turbine shaft 17. More precisely, the external diameter of the nut 52 is less than the internal diameter DI of the first shaft portion 15aa of the low-pressure compressor shaft 15 and greater than the external diameter D4 of the second shaft portion 17ab of the low-pressure turbine shaft 17. It is thus understood that the intermediate part 80 makes it possible to “raise” the nut, and thus to increase its capacity and its mechanical strength.

[0083] The nut 52 is engaged axially from upstream on the intermediate part 80 and is screwed until it is axially tightened against an annular projection 60 or the like of the low-pressure shaft of the first module 14. In particular, the low-pressure compressor shaft 15 comprises this annular projection 60 which extends radially inwards, i.e. towards the longitudinal axis C. In the present example, the annular projection 60 is formed upstream of the first internal and external splines 49, 50. In the present example, the annular projection 60 is formed at the boundary between the first portion 15aa and the second portion 15bb of the low-pressure compressor shaft 15. The nut 52 comprises a downstream lateral face 53, annular, bearing against an upstream annular surface 60a of the projection 60. The shaft low pressure turbine 17 can no longer move backward downstream, nor can the low pressure turbine.

[0084] Furthermore, the turbomachine 1 advantageously comprises an annular adjustment shim 70, arranged between the annular projection 60 of the low-pressure compressor shaft 15 and an annular shoulder 72 of the low-pressure turbine shaft 17. In the present example, the annular shoulder 72 extends radially outwards and is formed upstream of the first external splines 50 and downstream of the second external splines 83. The annular shoulder 70 has an external diameter denoted D6 and visible in [Fig. 4]. The diameter D6 of the annular shoulder 70 is less than the diameter D5 of the bottom of the first external splines 50. The adjustment shim 70 comprises an upstream lateral face 70a, annular, coming in bearing against a downstream annular surface 60b of the projection 60 and a downstream lateral face 70b, annular, bearing against an upstream annular surface 72a of the annular shoulder 72.

[0085] This axial adjustment shim 70 advantageously makes it possible to control or choose the position of the different elements of the connection.

[0086] The axial locking device 50 further comprises an additional axial locking system 90 configured to axially immobilize the intermediate part 80, and therefore the nut 52, relative to the low pressure turbine shaft 17 and therefore the low pressure compressor shaft 15 relative to the low pressure turbine shaft 17.

[0087] The additional axial locking system 90 comprises an annular row of teeth or dogs 92 arranged on the intermediate part 80 and configured to cooperate by dog ​​engagement with an annular row of slots 93 of the low-pressure turbine shaft 17.

[0088] Indeed, the intermediate part 80 comprises an annular row of radial teeth 92 which extend radially inward from an inner surface of the intermediate part. In the present example, the radial teeth 92 extend from an inner surface of the downstream portion 80bb of the intermediate part to the boundary with the upstream portion 80aa. The teeth 92 are arranged upstream of the second internal splines 82 of the intermediate part 80. The radial teeth 92 are regularly distributed around the longitudinal axis C. Each radial tooth 92 is intended to engage in a corresponding radial slot 93 of the low-pressure turbine shaft 17.

[0089] The low-pressure turbine shaft 17 comprises at its upstream end 17a radial lugs 94 which extend radially outwards from an internal annular face 17c of the low-pressure turbine shaft 17 and at a distance therefrom. The radial lugs 94 have an external diameter D8 (visible in [Fig.4]) smaller than the diameter D7 of the bottom of the second external splines 83.

[0090] Advantageously, each radial lug 94 extends over an angular sector around the longitudinal axis C. The lugs 94 are also spaced from each other so as to form the radial slots 93. In this way, slots 93 and lugs 94 are alternated around the longitudinal axis C. The lugs 94 and the slots 93 are arranged upstream of the second external splines 83 of the low-pressure turbine shaft 17. The slots 93 are shaped to allow the passage of the radial teeth 92 of the intermediate part 80. The lugs 94 of the low-pressure turbine shaft 17 are shaped to axially retain the radial teeth 92 of the intermediate part 80. In other words, after insertion of the radial teeth 92 through the slots 93, a rotation of the intermediate part 80 around its rotation axis allows the radial teeth 92 to come into axial abutment against the lugs 94 of the low pressure turbine shaft 17. Each tooth radial 92 has an upstream face 92a intended to bear against a downstream surface 94b of a lug 94. The intermediate part 80 can no longer move back upstream, nor can the nut 52.

[0091] On either side of the second external splines 83, the low-pressure turbine shaft 17 has two cavities with a diameter smaller than the diameter D7 of the bottom of the second external splines 83.

[0092] More precisely, the first portion 17aa of the low-pressure turbine shaft 17 has a first cavity 95 (visible in [Fig. 11]) arranged between the lugs 94 and the second external splines 83 and arranged to receive the annular row of radial teeth 92 of the intermediate part 80. The first cavity 95 has an external diameter smaller than the external diameter D8 of the radial lugs 94, and therefore than the diameter D7 of the bottom of the second external splines 83. The first cavity 95 is shaped to allow the axial displacement of the annular row of radial teeth 92 of the intermediate part 80. It extends in the axial direction so as to allow axial displacement downstream of the radial teeth 92 over a length denoted L5 and visible in [Fig.4].

[0093] Similarly, the second portion 17ab of the low-pressure turbine shaft 17 has a second cavity 96 (visible in [Fig. 11]) arranged between the second external splines 83 and the portion of the low-pressure turbine shaft receiving the annular projection 60, in particular of the low-pressure compressor shaft 15. The second cavity 96 is shaped to allow axial movement downstream of the intermediate part 80, and of the nut 52, during assembly without cooperation / engagement of the second internal and external splines 82, 83. The second cavity 96 extends in the axial direction over a length denoted D4 and visible in [Fig. 4].

[0094] These lengths L4 and L5 are advantageously greater than the extension length L1 of the second internal and external grooves 82, 83 to be able to ensure the axial positioning of the nut 52 downstream and to be able to rotate it to align the slots 93.

[0095] With reference in particular to Figures 7 and 8, the locking device 50 advantageously comprises a rotation locking system 100 which is configured so as to lock the nut 52 in its position. The rotation locking system 100 is configured in particular so as to prevent rotation of the nut 52.

[0096] The rotation locking system 100 advantageously comprises a first ring 102 also called an anti-rotation key, centered on the longitudinal axis C in the installation situation, intended to come to bear against a first annular face 103 of the nut 52. Second lugs 104 extend from the first annular face 103 of the nut 52 and at a distance from it, radially inwards.

[0097] Advantageously, each second lug 104 extends over an angular sector around the longitudinal axis C. The second lugs 104 are also spaced from each other so as to form second slots 105. In this way, second slots 105 and second lugs 104 are alternated around the longitudinal axis C.

[0098] The first ring 102 comprises at least one second radial tooth 106 which extends from an external peripheral edge thereof. In the case where there are several second radial teeth 106, these are regularly distributed around the longitudinal axis C. Each second radial tooth 106 is intended to engage in a corresponding radial notch 108 of the intermediate part 80 more visible in [Fig.5].

[0099] Indeed, with reference to [Fig.5], the intermediate part 80 comprises at its upstream end 80a, radial lugs 109 which extend radially upstream. Advantageously, each radial lug 109 extends over an angular sector around the longitudinal axis C. The lugs 109 are also spaced from each other so as to form the radial notches 108. In this way, radial notches 108 and radial lugs 109 are alternated around the longitudinal axis C.

[0100] Each second radial tooth 106 is also arranged in a second slot 105 of the nut 52.

[0101] The first rotation locking system 100 further comprises a second ring 110 which is centered on the longitudinal axis C in the installation situation. The second ring 110 is split generally like a circlip. The second ring 110 is received in an annular groove 112 of the nut 52. The annular groove 112 has an opening oriented towards the longitudinal axis C. The annular groove 112 is advantageously arranged upstream of the first annular face 103. More precisely still, the annular groove 112 is formed in the second lugs 104. Alternatively, the annular groove 112 is formed by a distance between the first annular face 103 of the nut 52 and an internal face of the second lugs. In this way, the second ring 110 extends upstream of the first ring 102 and the second lugs 104 make it possible to achieve axial locking of the second ring 110.Advantageously, the second ring 110 bears against an upstream face 102a of the first ring 102.

[0102] The rotation locking system 100 further comprises a second ring 110 which is centered on the longitudinal axis C in the installation situation. The second ring 110 is split generally like a circlip. The second ring 110 is received in an annular groove 112 of the nut 52. The annular groove 112 has an opening oriented towards the longitudinal axis C. The annular groove 112 is advantageously arranged upstream of the first annular face 103. More precisely, the annular groove 112 is formed in the second lugs 104. Alternatively, the annular groove 112 is formed by a distance between the first annular face 103 of the nut 52 and an internal face of the second lugs. In this way, the second ring 110 extends upstream of the first ring 102 and the second lugs 104 make it possible to achieve axial locking of the second ring 110. Advantageously, the second ring 110 bears against an upstream face 102a of the first ring 102. The second ring 110 makes it possible to axially lock the anti-rotation key, i.e. the first ring 102.

[0103] Advantageously, the locking device 50 further comprises a third ring 130 which is centered on the longitudinal axis C in the installation situation to axially lock the intermediate part 80 when the nut 52 is tightened. The ring 130 is generally split like a circlip. The ring 130 is received in an annular groove 132 of the intermediate part 80. In the present example, the annular groove is formed in the first portion 80aa of the intermediate part 80. The annular groove 132 has an opening oriented towards the longitudinal axis C. The annular groove 132 is advantageously arranged upstream of the radial teeth 92. In the present example, the annular groove 112 is formed at a distance from the upstream face 92a of the radial teeth 92 so that in the installation situation, a downstream face 130b of the third ring 130 advantageously bears against an upstream surface 94a of the lugs 94 of the low-pressure turbine shaft 17.In this way, the ring 130 extends upstream of the radial teeth 92 and the lugs 94 make it possible to achieve axial locking of the ring 130.

[0104] [Fig.9] illustrates the forces sizing this connection. The aerodynamic forces applied to the low pressure turbine are represented by the arrow F1 and the aerodynamic forces applied to the low pressure compressor, opposite to those of the low pressure turbine, are represented by the arrow F2. The tightening force of the nut to overcome the external axial forces is represented by the arrows F3, F4, F5 and F6 at different points of application.

[0105] We now refer to Figures 10 to 17 which illustrate steps of a method of mounting or reassembling the modules of the turbomachine. We understand that the disassembly of the modules of the turbomachine can be carried out by repeating these operations in reverse order in order to carry out maintenance operations on at least one of the modules of the turbomachine.

[0106] According to this method and as illustrated in the figures, the intermediate part 80 and the nut 52 are pre-assembled to each other by screwing so that the nut is axially set back relative to the intermediate part 80 forming the nut riser. More precisely, the nut 52 is not screwed entirely downstream onto the intermediate part 80. Of course, as a variant, the nut 52 can be mounted once the intermediate part is installed according to the other steps described below.

[0107] The proposed geometry of the different parts of the turbomachine and in particular that of the intermediate part 80, of the low pressure turbine shaft 17, of the nut 52 and of the low pressure compressor shaft 15, advantageously allows the assembly of the intermediate part 80 from upstream to downstream.

[0108] As indicated previously, the intermediate part 80 is provided with dogs 92 upstream and second internal grooves 82 downstream.

[0109] A first step of the method consists of approaching the assembly formed by the intermediate part 80 and the nut 52 from upstream to downstream. During this step and with reference to [Fig.10], the intermediate part 80 is inserted around the low-pressure turbine shaft 17 by aligning the radial teeth or dogs 92 of the intermediate part 80 with the slots 93 defined between the lugs 94 of the low-pressure turbine shaft 17.

[0110] The intermediate part 80 is thus moved in translation downstream so that the radial teeth or dogs 92 pass through the slots 93 until a downstream face 92b of the teeth 92 comes into axial abutment against an annular shoulder 120 or the like of the low-pressure turbine shaft 17. This annular shoulder 120 extends radially outwards. It is formed upstream of the second external splines 50 of the low-pressure turbine shaft 17. Thus, the downstream faces 92b of the teeth 92 come into abutment against an upstream annular surface 120a of the annular shoulder 120. The intermediate part 80 can no longer advance downstream, nor can the nut 52 assembled to the intermediate part 80. This step is illustrated in [Fig.l 1].

[0111] Alternatively, during this step, the intermediate part 80 is thus moved in translation downstream so that the radial teeth or dogs 92 pass through the slots 93 until a downstream face of the intermediate part 80 comes into axial abutment against the annular projection 60 of the low-pressure compressor shaft 15.

[0112] In this position, the second internal splines 82 of the intermediate part 80 and the second external splines 83 of the low-pressure turbine shaft 17 are not engaged with each other and therefore do not cooperate since the second internal splines 82 of the intermediate part 80 are axially offset downstream relative to the second external splines 83 of the low-pressure turbine shaft 17.

[0113] [Fig. 12] illustrates a step of angular positioning of the intermediate part 80 relative to the low-pressure turbine shaft 17. During this step, the intermediate part 80 is rotated around the low-pressure turbine shaft 17. In other words, the intermediate part 80 is moved in rotation around the longitudinal axis so that the radial teeth or dogs 92 are aligned with the lugs 94 of the low-pressure turbine shaft 17 which then form an axial stop for the radial teeth or dogs 92.

[0114] The intermediate part 80 is then moved in translation upstream until that the radial teeth 92 come into axial abutment against the lugs 94 of the low-pressure turbine shaft 17 as illustrated in [Fig.13]. Thus, the upstream faces 92a of the teeth 92 come into abutment against a downstream surface 94b of the lugs 94. The intermediate part 80 can no longer move upstream, nor can the nut 52 assembled to the intermediate part 80. In this way, the axial tightening force of the nut 52 will be taken up by the intermediate part 80.

[0115] In this position, the second internal splines 82 of the intermediate part 80 and the second external splines 83 of the low-pressure turbine shaft 17 are engaged with each other. In this way, the second splines 82, 83 will advantageously be used to be able to take up the torque which will be applied to the nut 52 during tightening.

[0116] [Fig. 14] represents an optional step of the method illustrating the implementation of the third split ring 130, for example a circlip, in the annular groove 132 of the intermediate part 80 to axially block the intermediate part 80 during the subsequent step of tightening the nut 52. Alternatively, the tool used for tightening the nut may comprise an arrangement for axially retaining this intermediate part 80.

[0117] The assembly continues with a step of tightening the nut 52 illustrated in [Fig. 15]. During the tightening of the nut 52 by threading, the nut 52 moves downstream relative to the intermediate part 80 forming a nut riser, and consequently relative to the low-pressure turbine shaft 17 and the low-pressure compressor shaft 15 until it comes into axial abutment against the annular projection 60 of the low-pressure compressor shaft 15.

[0118] The method continues with the installation of the anti-rotation device 100 ([Fig. 16]) making it possible to block the anti-rotation device 100 ([Fig. 17]). More precisely, this step comprises the installation of the first ring 102 then the installation of the second ring 110 of the rotation blocking system 100 from upstream to downstream. The first ring 102 is installed bearing against the first annular face 103 of the nut 52 so that each second radial tooth 106 of the first ring engages in a second slot 105 of the nut 52 then in a corresponding radial notch 108 of the intermediate part 80 in order to immobilize the nut 52 in rotation relative to the intermediate part 80. The second ring 110 is inserted into the annular groove 112 of the nut 52 to axially block the first ring 102.

[0119] With such a configuration, it is possible to disassemble and assemble only the low pressure shaft 9 while maintaining the other shafts of the other modules in the assembled position. The nut 52 and the intermediate piece 80 as well as the members (second ring 110 and first ring 102) are tightened against each other to perform, on the one hand, anti-rotation functions and, on the other hand, functions anti-axial displacement.

[0120] Figures 18 and 19 illustrate another embodiment of this device according to the invention in which the elements already described in the above are designated by the same references.

[0121] According to this embodiment, the additional axial locking system 90 configured to axially immobilize the nut 52 relative to the low-pressure turbine shaft 17 differs from that previously described in that it comprises another annular row of teeth or dogs arranged on the intermediate part 80 and configured to cooperate by dog ​​engagement with another annular row of slots of the low-pressure turbine shaft 17.

[0122] Thus, the intermediate piece 80 comprises a first annular row of radial teeth 92-1 and a second annular row of radial teeth 92-2 parallel to each other. The first annular row 92-1 and the second annular row 92-2 are arranged upstream of the second internal splines 82 of the intermediate piece 80. The second annular row of radial teeth 92-2 is arranged between the first annular row 92-1 and the second internal splines 82. The teeth 92-1, 92-2 of the first row and the second row extend radially inward from an inner surface of the intermediate piece. The radial teeth 92-1 of the first row are regularly distributed around the longitudinal axis C, as are the teeth 92-2 of the second row.

[0123] Preferably, the teeth 92-1 of the first row are angularly offset relative to the teeth 92-2 of the second row.

[0124] The first and second annular rows of teeth 92-1, 92-2 are configured to cooperate by dog ​​engagement with two annular rows of slots 93 of the low pressure turbine shaft 17.

[0125] More specifically, the low-pressure turbine shaft 17 comprises at its upstream end 17a a first annular row of radial lugs 94-1 which extend radially inward from the inner annular face 17c of the low-pressure turbine shaft 17 and at a distance therefrom and a second annular row of radial lugs 94-2 which extend radially inward from the inner annular face 17c. The two rows 94-1, 94-2 are parallel to each other. The second annular row of radial lugs 94-2 is arranged between the first annular row of radial lugs 94-1 and the second outer splines 83 of the low-pressure turbine shaft.

[0126] Advantageously, each radial lug extends over an angular sector around the longitudinal axis C. The lugs of the same annular row are also spaced from each other so as to form the radial slots. In this way, slots 93 and lugs 94 are alternated around the longitudinal axis C for each row. lugs 94-1, 94-2 and the slots are arranged upstream of the second external splines 83 of the low pressure turbine shaft 17.

[0127] Preferably, the lugs 94-1 of the first row are angularly offset relative to the lugs 94-2 of the second row.

[0128] The slots of the first row are shaped to allow the passage of the radial teeth of the second row 92-2 and of the first row 92-1 of the intermediate piece 80 while the slots of the second row are shaped to allow the passage of the radial teeth of the second row 92-2.

[0129] The lugs 94-1 of the first row of the low-pressure turbine shaft 17 are shaped to axially retain the radial teeth 92-1 of the first row of the intermediate piece 80. The lugs 94-2 of the second row of the low-pressure turbine shaft 17 are shaped to axially retain the radial teeth 92-2 of the second row of the intermediate piece 80. In other words, after insertion of the radial teeth 92-2 of the second row through the slots of the second row, a rotation of the intermediate piece 80 about its axis of rotation simultaneously allows the radial teeth 92-2 of the second row to pass through the slots of the second row and the radial teeth 92-1 of the first row to pass through the slots of the first row.Another rotation of the intermediate part 80 around its axis of rotation simultaneously allows the radial teeth 92-2 of the second row to come into axial abutment against the lugs 94-2 of the second row and the radial teeth 92-1 of the first row to come into axial abutment against the lugs 94-1 of the first row of the low-pressure turbine shaft 17.

[0130] This configuration advantageously makes it possible to increase the axial capacity of the force recovery. Of course, it is possible to increase the number of rows of axial stops beyond two. Similarly, the lugs of the first row can be aligned in an axial direction with the lugs of the second row.

Claims

Claims

1. Aircraft turbomachine (1), the turbomachine having a longitudinal axis (C) and comprising: - a first module (14) comprising a low-pressure compressor (4) and a low-pressure compressor shaft (15) which is centered on the longitudinal axis (C), - a second module (16) comprising a low-pressure turbine (8) and a low-pressure turbine shaft (17) which is centered on the longitudinal axis (C), the low-pressure turbine shaft (17) comprising a downstream end connected to a rotor of the low-pressure turbine and an upstream end (17a) connected to a rotor of the low-pressure compressor, and - a locking device (50) configured so as to axially immobilize the low-pressure turbine shaft (17) of the second module (16) relative to the low-pressure compressor shaft (15) of the first module (14), characterized in that the locking device (50) comprises a nut (52) and an intermediate piece (80), each centered on the longitudinal axis (C),the nut (52) being screwed onto a thread of the intermediate part (80), and the intermediate part cooperating with the upstream end (17a) of the low pressure turbine shaft (17) and the nut (52) bearing against an annular projection (60) of the first module (14).,

2. Turbomachine (1) according to claim 1, in which the low pressure turbine shaft (17) comprises external splines (83) oriented parallel to the longitudinal axis (C) and the intermediate part (80) comprises internal splines (82) complementary to said external splines (83), the intermediate part (80) being axially engaged on the low pressure turbine shaft (17) so that the intermediate part (80) and the low pressure turbine shaft (17) are integral in rotation by engagement of their splines (82, 83).

3. Turbomachine (1) according to claim 1 or 2, in which the axial locking device (50) comprises an additional axial locking system (90) configured to axially immobilize the intermediate part (80) relative to the low pressure turbine shaft (17).

4. Turbomachine (1) according to claim 3, in which the additional axial locking system (90) comprises at least one annular row of radial teeth (92) arranged on the intermediate part (80). and configured to cooperate by dog clutching with an annular row of radial slots (93) of the low pressure turbine shaft (17).

5. Turbomachine (1) according to the preceding claim 4, in which the locking device (50) comprises a ring (130) centered on the longitudinal axis (C) and received in an annular groove (132) formed in the intermediate part (80) upstream of the at least one annular row of radial teeth (92).

6. A turbomachine (1) according to any preceding claim, wherein the locking device (50) comprises a rotation locking system (100) configured to hold the nut (52) in position against the projection (60).

7. Turbomachine (1) according to the preceding claim 6, in which the rotation locking system (100) comprises: - a first ring (102), centered on the longitudinal axis (C) and intended to bear against a radial annular face (103) of the nut (52), the first ring (102) comprising at least one radial tooth (106) intended to each engage in a radial notch (108) of the intermediate part (80), and - a second ring (110), centered on the longitudinal axis (C) and received in an annular groove (112) of the nut (52), the annular groove (112) being formed upstream of the radial annular face (103).

8. A turbomachine (1) according to any preceding claim, wherein the upstream end (17a) of the low pressure turbine shaft (17) extends inside the low pressure compressor shaft (15), the nut (56) and the intermediate piece (80) being mounted inside the low pressure compressor shaft (15) which comprises the shoulder (60), the intermediate piece being arranged radially between the nut (52) and the upstream end (17a).

9. Method for mounting an aircraft turbomachine (1) according to one of the preceding claims, characterized in that it comprises the steps of: - installing the intermediate part (80) on the upstream end (17a) of the low pressure turbine shaft (17) from upstream to downstream; - axial immobilization of the intermediate part (80) relative to the low pressure turbine shaft (17); - screwing the nut (52) onto the intermediate part (80); and - locking the nut (52) in rotation.

10. Method of mounting a turbomachine (1) according to claim previous, in which the nut is pre-assembled to the intermediate piece (80) by screwing before installation of the intermediate piece (80) on the low pressure turbine shaft (17).

11. Method of mounting a turbomachine (1) according to claim 9 or 10, comprising axial locking of the intermediate part (80) before tightening the nut (52).

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