FR3140123A1 - MODULARITY OF AN AIRCRAFT TURBOMACHINE BY AN AXIAL AND ROTATIONAL LOCKING DEVICE, CORRESPONDING ASSEMBLY METHOD - Google Patents

Abstract

The invention relates to a turbomachine comprising: - a first module comprising a speed reducer (3) having an input shaft (12), - a second module comprising a low pressure compressor which is connected to the first module, - a third module comprising a low pressure shaft which is centered on a longitudinal axis , the blocking device comprising: - a first nut (60) screwed onto a thread of the low pressure shaft and resting against an annular projection of the second module, - an anti-displacement member (65) configured to axially block the first nut, - a second nut (73) screwed onto a thread of the second module and configured to axially immobilize the anti-displacement member, and - a third nut (93) screwed onto the anti-displacement member. Figure for abstract: Figure 2

Description

MODULARITY OF AN AIRCRAFT TURBOMACHINE BY AN AXIAL AND ROTATIONAL LOCKING DEVICE, CORRESPONDING ASSEMBLY METHOD Field of the invention

The present invention relates to solutions for facilitating the modularity of an aircraft turbomachine.

Technical background

An aircraft turbomachine is often produced in the form of an assembly of modules which can each include fixed parts and moving parts. A module is defined as a subassembly of a motor which has geometric characteristics at the level of its interfaces with adjacent modules which are sufficiently precise for it to be delivered individually, and which has undergone distinct balancing when it includes rotating parts. The assembly of the modules makes it possible to constitute a complete engine, reducing as much as possible the balancing and matching operations of the interface parts.

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, the turbomachine is configured so as to obtain a division into 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: a major upstream module for the front part including the fan, a major intermediate module for the intermediate part including the low pressure compressor and the high pressure body and a major downstream 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 for the low pressure body to be divided equally into three modules with the low pressure compressor arranged independently of the rest of the intermediate major module.

Maintenance is particularly difficult on a turbomachine comprising a reduction gear and possibly an upstream blade pitch change system. In fact, the speed reducer is attached either to the upstream module or to the major intermediate module. The speed reducer includes an input shaft which is connected to a rotor of the low pressure compressor and a rotor of the low pressure turbine. In particular, the major intermediate module and the major downstream module which include members of the low pressure body, and the upstream module, are fixed to each other using a nut which is centered on the axis of the turbomachine and which is used to axially tighten the speed reducer input shaft and the low pressure shaft.

During a maintenance operation on the speed reducer or other components of the turbomachine of one of the modules exposed above, this nut must be unscrewed from upstream using a tool which is inserted into the turbomachine along its longitudinal axis. This allows the major downstream module to be separated. However, this is not sufficient to completely free the input shaft since the latter is also connected to the rotor of the low pressure compressor via a journal which is fixed on the input shaft and that It also needs to be dismantled. The rotor of the low pressure compressor of the intermediate major module further includes bearings whose internal rings are fixed on the input shaft.

The problem in this case is therefore the number of parts to disassemble to disassemble a component of one of the modules and specifically the input shaft. It is generally not possible to dismantle the speed reducer without disassembling a large part of the turbomachine including the upstream module, the major intermediate module and the major downstream module.

The present invention proposes 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.

We achieve this objective in accordance with the invention thanks to a turbomachine, in particular for an aircraft, the turbomachine having a longitudinal axis and comprising:
- a first module comprising a speed reducer which includes an input shaft centered on the longitudinal axis,
- a second module comprising a low pressure compressor, the second module being connected to the first module,
- a third module comprising a low pressure shaft which is centered on the longitudinal axis, the low pressure shaft comprising an upstream end connected to the input shaft, and
- a blocking device configured so as to axially immobilize the third module relative to the first module,
the blocking device being is configured so as to axially immobilize the second module relative to the first module and the second module and comprises:
- a first nut which is screwed onto a thread of the upstream end of the low pressure shaft and rests against an annular projection of the second module,
- an anti-displacement member which is configured so as to axially limit the movement of the first nut,
- a second nut which is screwed onto a thread of the second module and which is configured so as to axially immobilize the anti-displacement member, and
- a third nut which is screwed onto the anti-displacement member.

Thus, this solution makes it possible to achieve the aforementioned objective. The low pressure turbine and low pressure compressor module can thus be dismantled in a reduced number of operations compared to the other modules and without dismantling the other adjacent modules. This particularly applies to the input shaft which is subjected to numerous stresses and which can now be checked and replaced easily and quickly. The input shaft can be dismantled independently of the other shafts thanks to the locking device which includes several nuts and members tightened/engaged on each other to achieve anti-rotation and anti-displacement or axial locking functions. Furthermore, this configuration allows a gain in modularity and a saving of time in terms of inspection of parts and independent dismantling of some of them. This modularity is part of an approach to reducing the environmental impact since it allows only the necessary components to be repaired and checked and to reduce the downtime of the turbomachine.

The turbomachine according to the invention may comprise one or more of the following characteristics, taken in isolation from each other or in combination with each other:

- the locking device comprises a locking element cooperating with the first nut and the third nut.

- the first nut is mounted to rotate freely around the longitudinal axis.

- the second module comprises a low pressure compressor shaft which is connected to the low pressure compressor and which is centered on the longitudinal axis, the low pressure compressor shaft being connected to the input shaft and to the low shaft pressure.

- the low pressure compressor shaft comprises the annular projection and the first nut has a downstream face bearing against an upstream face of the annular projection.

- the anti-displacement member comprises a plurality of teeth each intended to engage in a notch of the low pressure compressor shaft.

- the plurality of teeth has an external diameter greater than an external diameter of a flange of the first nut.

- the second nut is intended to be blocked in rotation by a first blocking system.

- the first blocking system includes:
- - a first ring, centered on the longitudinal axis and intended to come to bear against a radial annular face of the second nut, the first ring comprising a plurality of radial teeth intended to each engage in a radial notch of the shaft low pressure compressor, and
- - a second ring, centered on the longitudinal axis and received in an annular groove of the second nut, the annular groove being arranged upstream of the radial annular face.

- the turbomachine comprises a second locking system configured so as to lock the third nut in an annular cavity of the input shaft.

- the third nut is intended to be blocked in translation towards upstream at least by a second blocking system.

- the second blocking system includes:
- - a third ring, centered on the longitudinal axis, and comprising a plurality of radial teeth which have downstream faces intended to bear against an annular face of the input shaft, the third ring comprising an upstream face against which abuts a downstream face of the third nut, and
- - a fourth ring, centered on the longitudinal axis, received in an annular groove of the input shaft, the fourth ring facing the downstream faces of the radial teeth.

- the first module comprises a fan which is connected to a fan shaft and which is arranged upstream of the second module, the low pressure shaft rotating the fan shaft via the speed reducer.

- the fan is ducted.

- the gearbox is located in a lubrication enclosure.

- the low pressure compressor shaft is independent of the input shaft and the low pressure shaft.

- the low pressure shaft comprises an upstream end which extends inside the low pressure compressor shaft, the first nut, the second nut and the third nut being mounted inside the compressor shaft low pressure.

- the low pressure compressor shaft is connected to an upstream end of the low pressure shaft and to a downstream end of the input shaft.

- the low pressure compressor shaft is connected to a rotor of the low pressure compressor.

- the low pressure compressor shaft is connected to the low pressure compressor rotor via a journal, the journal being integral with the low pressure compressor rotor and the low pressure compressor shaft.

- the journal is formed in one piece with the low pressure compressor shaft.

- the third module comprises a low pressure turbine connected to the low pressure shaft, the low pressure shaft comprises a downstream end connected to a low pressure turbine rotor.

- the input shaft of the speed reducer has an internal diameter which is less than the internal diameter of the low pressure compressor shaft.

- the input shaft of the speed reducer has an internal diameter which is greater than the internal diameter of a downstream end of the low pressure compressor shaft.

- the first nut includes a thread which is screwed onto the third module.

- the radial notches of the low pressure compressor shaft extend radially outside the second nut.

The invention further relates to an aircraft comprising at least one turbomachine as mentioned above.

The invention also relates to a method of assembling a turbomachine as mentioned above, the method comprising the steps of:
- screwing the first nut onto the low pressure shaft,
- limitation in translation of the first nut on the low pressure compressor shaft along the longitudinal axis by means of the anti-displacement member,
- axial immobilization of the anti-displacement member by means of the second nut, and
- screwing the third nut onto the anti-displacement member.

According to a characteristic of the method, it comprises a step of engaging a locking element on the third nut and on the first nut.

Brief description of the figures

Other characteristics and advantages of the invention will appear during reading of the detailed description which follows, for the understanding of which we will refer to the appended drawings in which:

There is a half schematic view in axial section of an aircraft turbomachine;

There is a detailed view of the according to the invention;

There is a perspective view illustrating a shaft of one of the modules of a turbomachine according to the invention;

There is a perspective view of a shaft in which a first nut is mounted following a step of an assembly method according to the invention;

There is a perspective view of a shaft in which is mounted an anti-displacement member of a first nut following a step of an assembly method according to the invention;

There is a detailed view of the according to the invention;

There is a perspective view and substantially along a longitudinal section plane of a shaft in which a second nut and a locking system for this nut are mounted following a step of an assembly method according to the invention;

There illustrates in more detail a first system for blocking rotation of a second nut according to the invention;

There is a detailed view of the and substantially along a radial section plane of the shaft in which the second nut according to the invention is mounted;

There is a perspective view of a shaft in which a third nut is mounted following a step of an assembly method according to the invention;

There is a perspective view of a shaft in which a locking system is mounted following a step of an assembly method according to the invention;

There illustrates in more detail a third nut according to the invention;

There is a perspective view of a step of the assembly process according to the ;

There is a perspective view of a shaft in which a locking system is mounted following a step of an assembly method according to the invention;

There is a perspective view in which two shafts are assembled together following a step of an assembly method according to the invention; And

There is a perspective view and in which a blocking device makes it possible to block the translation and rotation of the shafts following a step of an assembly method according to the invention.

Detailed description of the invention

The invention applies to an aircraft turbomachine 1 such as that shown in the and which is a turbojet equipped with a ducted fan 2 and a speed reducer 3. Of course, the invention is not limited to a turbojet and can be applied to any type of turbomachine equipped in particular with a speed reducer.

The turbomachine 1 extends along a longitudinal axis X which is generally the axis of rotation of its rotors. The turbomachine 1 comprises, from upstream to downstream along the longitudinal axis and a low pressure turbine 8.

The low pressure compressor 4 and the low pressure turbine 7 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 8 are mechanically connected by a high pressure shaft 10 so as to form a high pressure body. The low pressure shaft 9 extends at least partly inside the high pressure shaft 10 and are coaxial.

The turbomachine 1 is configured with several modules which are assembled/connected to each other and which facilitate its maintenance. Trees and/or interfaces make it possible to make these connections.

A first module 11 comprises the fan 2 and the speed reducer 3. The latter advantageously comprises an input shaft 12 which is centered on the longitudinal axis advantageous.

The blower 2 comprises a blower shaft 13 which is advantageously rotated by the low pressure shaft 9 via the speed reducer 3.

A second module 14 comprises the low pressure compressor 4. The second module 14 also comprises a low pressure compressor shaft 15 to which the low pressure compressor 4 is connected. The low pressure compressor shaft 15 is centered on the longitudinal axis X.

A third module 16 comprises the low pressure turbine 7 and the low pressure shaft 9 which is centered on the longitudinal axis X. The low pressure shaft 9 advantageously comprises an upstream end 9a connected to a rotor of the low pressure compressor and a downstream end 9b connected to a low pressure turbine rotor. The upstream end 9a is connected to the input shaft 12 of the speed reducer 3.

A fourth module 17 comprises the high pressure compressor 5. Advantageously, the fourth module 17 comprises the high pressure turbine 7. The fourth module 17 also comprises the annular combustion chamber 6 which is interposed axially between the high pressure compressor 5 and the high turbine pressure 7.

According to this configuration, the low pressure body of the turbomachine 1 is divided into three modules. Alternatively, the low pressure body is divided into two modules with the low pressure compressor forming part of the second module.

The 3 speed reducer (known by the English acronym “RGB”) includes an epicyclic gear train. Of course, the speed reducer could include a planetary type gear.

The speed reducer 3 typically comprises a solar 20 (or internal sun gear), a plurality of satellites 21 (which are pinions), a planet carrier 22 and an external ring gear 23 (or external sun gear). The solar 20 is centered on the longitudinal axis by the satellite carrier 22. The satellites 21 are each mounted freely in rotation around a satellite axis using a bearing and mesh with the external teeth of the solar 20 and the internal teeth of the external crown 23.

In the present case, the external ring 23 is immobile and fixed to a stator of the turbomachine which is here an input casing 24. The solar 20 is movable in rotation and coupled to the input shaft 12 which itself is connected to the low pressure shaft 9. The planet carrier 22 is also movable 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.

In the case of a planetary type gear reducer, the outer ring is integral in rotation with the fan shaft, the planet carrier is integral with a fixed structure such as the inlet casing 24.

The reducer 3 of the is advantageously arranged in a lubrication enclosure 25 which extends around the longitudinal axis X. The enclosure 25 therefore has a generally annular shape. The enclosure 25 is delimited by the fan shaft 13 and the input shaft 12 at its internal periphery. At its external periphery, the lubrication enclosure 25 is advantageously delimited, but not restrictively, by the inlet casing 24 which extends around the reduction gear 3. The enclosure 25 is delimited upstream by a first bearing support 26 which is annular. The first bearing support 26 for example comprises an outer end which is fixed to the input casing 24 and an inner end which maintains outer bearing rings of two rolling bearings 27.

Advantageously, the rolling bearings 27 comprise internal rings which are fixed to the fan shaft 13. These bearings allow the rotational guidance of at least the fan shaft 13. One of the upstream bearings closest to the reducer speed 3 also makes it possible to guide the rotating planet carrier in a more stable manner. This bearing closest to the gearbox is optional.

Finally, the enclosure 25 is delimited downstream for example by a second bearing support 28 which is annular. The second bearing support 28 includes an outer end 28a which is attached to the input housing 24 and an inner end 28b which holds outer rings of two rolling bearings 29.

Advantageously, the two downstream rolling bearings 29 allow the guidance of the input shaft of the speed reducer and the low pressure compressor shaft (which is integral with the input shaft).

In the present example, the rolling bearings 29 comprise internal rings which are fixed to the low pressure compressor shaft 15. The second bearing support 28 comprises an annular ferrule 30 whose first end 30a is fixed to the second bearing support 28 and whose second end 30b cooperates with sealing elements 31 installed around the low pressure compressor shaft 15.

In reference to the , the enclosure 25 also comprises sealing means sealingly closing the enclosure 25. These sealing means comprise a first removable cover 32 intended to close the enclosure 25 upstream and in a watertight manner and a second cover 33 removable designed to close the enclosure downstream and also in a watertight manner. The first cover 32 is mounted inside the fan shaft 13 and is located near the speed reducer 3 along the longitudinal axis. The second cover 33 is mounted inside the input shaft 12 and at a downstream end 12b thereof. This second cover 33 is mounted downstream of the speed reducer 3 (and more precisely downstream of flexibility means in an advantageous manner).

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

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

On the , a set of shafts of the turbomachine are connected together and locked in position relative to each other. The assembly includes a first tree and a second tree. In the present example, the first shaft is the input shaft 12. The second shaft is the low pressure compressor shaft 15. The set of shafts also includes a third shaft which is the low pressure shaft 9.

First coupling means 40 are configured so as to connect (removably) the first module 11 and the second module 14. Second coupling means 41 are configured so as to connect (removably) the second module 11 and the third module 15.

The turbomachine comprises a blocking device 42 configured so as to connect the modules together and to axially immobilize the modules between them.

The low pressure compressor shaft 15 is connected to the low pressure compressor rotor via a journal 43. In particular, the second module 14 comprises (in addition to the low pressure compressor) the journal 43 which is integral in rotation of the low pressure compressor rotor and the low pressure compressor shaft 15. The low pressure compressor shaft 15 is connected to the input shaft 12.

As shown on the , the low pressure compressor shaft 15 comprises a general right cylindrical shape with axis A. The low pressure compressor shaft advantageously extends between an upstream end 15a and a downstream end 15b. The annular pin 43 extends radially from an external surface of the low pressure compression shaft 15 to a first end 43a. The pin 43 comprises a second end 43b which is secured to the rotor via fixing members such as a threaded rod (screw) and a nut. In the example shown, the pin 43 is formed in one piece with the low pressure compressor shaft 15. Alternatively, the pin 43 is an attached part and its internal end 43a is fixed and immobilized axially to the downstream end 15b of the low pressure compressor shaft 15.

The low pressure compressor shaft 15 advantageously includes an annular seat 44 which rises radially from the outer surface thereof. The internal ring 29a of one of the bearings 29 bears axially against this annular bearing surface 44.

The low pressure compressor shaft 15 comprises an external thread 45 which is intended to engage with an internal thread of a bearing nut 46 which axially blocks the internal ring 29a. The external thread 45 is arranged towards the upstream end 15a of the low pressure compressor shaft 15.

As stated previously, the low pressure compressor shaft 15 is connected to the input shaft 12. The low pressure compressor shaft 15 is coupled to the input shaft 12 by means of splines of so as to transmit a rotational torque. For this purpose and as shown on the , the first coupling means 40 comprise first internal splines 47 which are formed on an internal surface 48 of the low pressure compressor shaft 15. The first internal splines 47 are oriented along the axis A (and along the axis longitudinal) and are arranged regularly around the axis A. The first internal splines 47 are configured to engage with corresponding first external splines 49 of the input shaft 12. The first internal splines 47 are located near advantageously, but not restrictively, of the upstream end 15a of the shaft 15.

The low pressure compressor shaft 15 comprises second internal splines 50 which are formed on the internal surface 48. These second external splines 50 are oriented along the axis A and are regularly distributed around this axis A. These are located advantageously at the downstream end 15b of the low pressure compressor shaft.

In the example shown, the low pressure compressor shaft 15 comprises a first shaft portion 15aa, a second shaft portion 15ab and a third shaft portion 15ac. The first portion 15aa comprises an internal diameter D1 which is greater than the internal diameter D2 of the second portion 15ab. The internal diameter D2 of the second portion 15ab is greater than the internal diameter D3 of the third portion 15ac.

The low pressure compressor shaft 15 advantageously, but not limited to, comprises an annular projection 51 which extends radially towards the interior thereof. The annular projection 51 is arranged between the first shaft portion 15aa and the third shaft portion 15ac. More precisely, the annular projection 51 is arranged between the second portion 15ab and the third portion 15ac. In the present example, the annular projection 51 is formed upstream of the grooves 50.

The low pressure compressor shaft 15 further comprises an annular shoulder 52 extending radially inwardly therefrom. The shoulder 52 is arranged between the first shaft portion 15aa and the third shaft portion 15ac. More precisely, the annular shoulder 52 is arranged upstream of the annular projection 51 along the longitudinal axis X.

In Figures 2 and 3, the downstream end 12b of the input shaft 12 extends inside the low pressure compressor shaft 15. The corresponding first external splines 49 are formed on an external surface of the input shaft 12. The first external splines 49 are located at the downstream end 12b of the shaft 12. The latter has an external diameter at the level of the downstream end 12b which is advantageously substantially less than the diameter internal D1 of the first portion 15aa of the low pressure compressor shaft 15.

The input shaft 12 also has an external diameter D4 at the speed reducer 3 which is, advantageously, less than the external diameter of its downstream end 12b. The efficiency of the turbomachine also depends on the radial dimensions of the speed reducer; the diameter of the input shaft 12 must be small so that the ratio of the diameters of the external ring and the solar is close to 1.

Advantageously, the diameter D4 of the input shaft 12 is between:
- a sufficient radius to be able to pass the rotation torque,
- a sufficient radius to be able to pass external tools (described later) inside the input shaft 12,
- the lowest possible radius to save mass, and
- a radius as low as possible to leave height for the flexible elements (the height of these elements induces the flexibility of the part).

Advantageously, the reduction ratio of the speed reducer is between 2.5 and 7. The diameter of the input shaft 12 must be sufficiently small so as to achieve the desired reduction ratio while being large enough to be able to pass the torque and a tool. The ratio between the diameter of the crown and the diameter of the input shaft 12 must be the reduction ratio - 1 (the Willis formula expressing a reduction ratio between the crown and the solar, in the frame of the carrier satellites).

The input shaft 12 has a certain flexibility so as to avoid hyperstatism in the speed reducer 3. The input shaft 12 advantageously comprises, but not limited to, bellows, which with the splines, make it possible to produce this flexibility. Thus, a misalignment can occur between the input shaft 12 and the low pressure compressor shaft 15 which is particularly interesting in the case of a relatively long engine.

On the , the low pressure compressor shaft 15 is integral in rotation with the low pressure shaft 9. The low pressure compressor shaft 15 is coupled to the low pressure shaft 9 advantageously by means of splines so as to transmit a torque of rotation. The second coupling means 41 are advantageously formed by the grooves. In particular, the upstream end 9a of the low pressure shaft 9 extends inside the low pressure compressor shaft 15. The low pressure shaft 9 comprises second external splines 53 which correspond and which are engage with the second internal splines 50 of the low pressure compressor shaft 15. The second external splines 53 are arranged on an external surface of the lower shaft 9 and towards its upstream end. The low pressure shaft 9 has an external diameter (at its upstream end 9a) which is substantially less than the diameter of the third portion 15ac of the low pressure compressor shaft 15.

The blocking device 42 is configured so as to immobilize the low pressure shaft 9 relative to the low pressure compressor shaft 15, the input shaft 12 relative to the low pressure compressor shaft 15 and the input shaft 12 relative to the low pressure shaft 9.

In reference to the , the blocking device 42 comprises a first nut 60 which is configured so as to axially block at least partially the low pressure shaft 9 relative to the low pressure compressor shaft 15. Advantageously, the first nut 60 is screwed onto a thread of the upstream end 9a of the low pressure shaft 9 and resting against an annular projection 51 of the second module 14. The first nut 60 is configured so as to axially immobilize the low pressure shaft 9 relative to the low pressure compressor shaft 15 and to achieve the recovery of the axial thrust of the low pressure turbine.

Advantageously, the first nut 60 comprises a cylindrical body 61 with an axis of revolution B. The first nut 60 comprises a flange 62 which extends radially outwards from one end of the cylindrical body 61. The first nut 60 comprises in the present example an L-shaped axial section.

The first nut 60 is screwed onto the low pressure shaft 9 and is centered on the longitudinal axis. The first nut 60 is arranged radially, advantageously, between the low pressure compressor shaft 15 and the low pressure shaft 9. More precisely, the first nut 60 comprises an external thread 63 which engages with an internal thread 64 of the low pressure shaft 9. The external thread 63 is carried by an external surface of the cylindrical body 61. The internal thread 64 is advantageously located at the upstream end 9a of the low pressure shaft 9.

In the present example, the external diameter of the nut 60, at the level of the cylindrical body 61, is less than the internal diameter of the low pressure shaft 9. We can see that the internal diameter of the nut is less than the internal diameter of the input shaft 12 (see ).

The flange 62 of the first nut 60 comprises an annular face intended to bear against a complementary annular surface of the annular projection 51. In particular and advantageously, the annular face is a downstream annular face 62b and the complementary annular surface is a surface complementary upstream annular 51a.

With reference to Figures 5 and 6, the blocking device 42 comprises an anti-displacement member 65 which is configured so as to “lower” the fixing means (here thread) and to allow assembly between the input shaft 12 and a third nut 90 described later (in particular the engagement of the internal thread 72 of the cylindrical body 66 of the anti-displacement member 65 and the external thread 95 of the cylindrical body 90a of the third nut 90).

Advantageously, the collar 62 is arranged between the anti-displacement member 65 and the annular projection 51.

Advantageously, the first nut 60 is mounted to rotate freely in the low pressure compressor shaft 9 as explained later. There is some axial and radial play between other parts. When the various components are loosened, the first nut 60 can move axially and rotate freely in a short space. When the different members are tightened, a first rotation locking system 77 abuts against the anti-displacement member 65. The latter allows the axial movement (according to the clearance which is provided) of the first nut. The first nut 60 faces and/or abuts against the annular projection 51 of the compressor shaft 15.

The anti-displacement member 65 advantageously comprises a cylindrical body 66 with an axis of revolution C. The anti-displacement member 65 is centered on the axis X in the installation situation. The anti-displacement member 65 advantageously comprises an annular wing 67 which extends radially outwards from one end of the cylindrical body 66. A plurality of teeth 68 extend from a downstream face 67b of the annular wing 67 and along the axis of revolution C. The teeth 68 are located in particular near the external peripheral edge 69 of the annular wing 67. The downstream face 67b is arranged facing an upstream annular face 62a of the flange 67 of the first nut 60.

Advantageously, at least one axial clearance J1 is provided between the downstream face 67b and the upstream annular face 62a which allows the rotation of the first nut 60 around the longitudinal axis X.

The anti-displacement member 65 comprises teeth 68 (those described above) which are intended to engage respectively in notches 70 of complementary shape of the second module. In particular, as can be seen in the , the low pressure compressor shaft 15 comprises notches 70 which are oriented along the longitudinal axis. The notches 70 are arranged upstream of the annular projection 51 advantageously.

In installation situation, the teeth 68 extend radially outside the annular edge 71 of the flange 62 of the first nut 60. In other words, the external diameter of the plurality of teeth 68 is greater than the external diameter of the annular edge 71 of the collar 62.

The distance L1 measured between the bottom of the notches 70 and the downstream face 67b (in an installation situation along the longitudinal axis X) is greater than the distance L2 measured between the upstream annular surface 51a complementary to the projection 51 and the downstream face 67b. In the present example, the bottom of the notches 70 is in the same plane as the complementary upstream annular surface 51a. This difference between the distances L1 and L2 creates the axial play J1 which is referenced on the .

On the , the anti-displacement member 65 comprises an internal thread 72 which is formed on the internal surface of its cylindrical body 66.

Advantageously, the external diameter of the cylindrical body 66 of the anti-displacement member 65 is greater than the external diameter of the cylindrical body 61 of the first nut 60.

In reference to the , the blocking device 42 also comprises a second nut 73 which is screwed onto a thread of the second module 14 and which is configured so as to axially immobilize the anti-displacement member 65, i.e. along the longitudinal axis 73 comprises a cylindrical body with an axis coaxial with the longitudinal axis. The cylindrical body advantageously extends between a first annular face 74a and a second annular face 74b. The second nut 73 includes an external thread 74 formed on its external surface 75 and which is intended to engage with an internal thread 76 of the low pressure compressor shaft 15. The internal thread 76 is provided at the second portion shaft 15ab.

The second nut 73 has an external diameter which is greater than the external diameter of the anti-displacement member 65. The internal diameter of the second nut 73 is also greater than the external diameter of the anti-displacement member 65. A radial space is provided between the second nut 73 and the anti-displacement member 65. This radial space makes it possible, on the one hand, to avoid parasitic force transitions and on the other hand, the integration of the locking rings (not shown) of the second nut 73. In installation situation, the second annular face 74b of the second nut 73 bears against an upstream face 67a of the annular wing 67.

As is also visible in Figures 7, 8 and 9, the second nut 73 is locked in rotation by a first rotation locking system 77. The first rotation locking system 77 advantageously comprises a first ring 78, centered on the longitudinal axis, intended to come to bear against the first annular face 74a of the second nut 73. Lugs 80 extend from the first annular face 74a of the second nut 73 and at a distance therefrom, radially inwards.

Advantageously, each lug 80 extends over an angular sector around the longitudinal axis. The lugs 80 are also spaced from each other so as to form slots 81. In this way, slots 81 and lugs 80 are alternated around the longitudinal axis.

The first ring 78 includes a plurality of radial teeth 82 which extend from an outer peripheral edge (not shown) thereof. The radial teeth 82 are regularly distributed around the longitudinal axis precisely illustrated on the ) are open (and open) onto the internal surface 48 and are turned towards the inside of the low pressure compressor shaft 15. The notches 84 are advantageously, but not limited to, formed at the level of the annular shoulder 52.

Each radial tooth 82 is also arranged in a slot 81 of the second nut 73.

As is also visible on the , the radial notches 84 open onto an annular surface 86, centered on the axis

The first rotation locking system 77 further comprises a second ring 85 which is centered on the longitudinal axis X. The second ring 85 is generally split like a circlip. The second ring 85 is received in an annular groove 87 of the second nut 76. The annular groove 87 has an opening oriented towards the longitudinal axis X. The annular groove 87 is advantageously arranged upstream of the first annular face 74b. Even more precisely, the annular groove 87 is formed in the lugs 80. Alternatively, the annular groove 87 is formed by a distance between the first annular face 74a of the second nut and an internal face of the lug 74a. In this way, the second ring 85 extends upstream of the first ring 78 and the lugs 80 make it possible to achieve axial blocking of the second ring 85. Advantageously, the second ring 85 bears against an upstream face of the first ring 78.

On the , the blocking device 42 comprises a third nut 90 which is intended to be screwed onto the anti-displacement member 65. The third nut 90 is also intended to be immobilized axially on the input shaft 12. Such as illustrated, the third nut 90 is advantageously installed in an annular cavity 91 of the input shaft 12. Advantageously, but not restrictively, the annular cavity 91 is delimited along the longitudinal axis by an upstream shoulder 92 and by a radial tab 93. The annular cavity 91 is also delimited radially by a wall portion of the downstream end 12b of the input shaft 12.

In the present example, the third nut 90 comprises a cylindrical body 90a of axis D and an annular flange 94 extending radially from one end of the third nut 90. The third nut 90 comprises an external thread 95 which is intended to be engage with an internal thread 96 of the anti-displacement member 65.

Advantageously, the external diameter of the cylindrical body 90a of the third nut 90 is significantly less than the internal diameter of the cylindrical body of the anti-displacement member 65.

The annular sole 94 includes an external peripheral edge 97 (cf. ) which defines a diameter which is less than the internal diameter of the downstream end 12b of the input shaft 12. The annular sole 94 comprises an upstream face 94a and a downstream face 94b which are opposite along the axis D.

Advantageously, the upstream face 94a comprises a plurality of protuberances 98 which extend along the axis D. These protuberances 98 are intended to engage in recesses of a tightening tool (not shown). The latter allows the tightening of this third nut 90 on the anti-displacement member 65.

In Figures 11, 12 and 13, there is provided a second locking system 100 configured so as to enclose the third nut 90 in the annular cavity 91 of the input shaft 12. Advantageously, the third nut 90 is intended to be blocked axially at least in part by the second blocking system 100. This axial blocking occurs in particular when all the parts are tightened (screwed, etc.). The second blocking system 100 advantageously comprises a third ring 101 of axis E and is centered on the longitudinal axis in the installation situation. The third ring 101 makes it possible to integrate and enclose the third nut 90 inside the input shaft 12. The third ring 101 advantageously comprises an upstream face 101a and a downstream face 101b which are connected by an internal peripheral border 102a and an external peripheral border 102b. The third ring 101 advantageously comprises a plurality of radial teeth 103 which extend radially outwards from the external peripheral edge 102b.

The downstream face 94b of the third nut 90 bears against the upstream face 101a of the third ring 101. Each radial tooth 103 comprises a downstream face 103b intended to bear against an annular face (upstream face 93a) of the radial tab 93. This the latter also comprises an annular downstream face 93b opposite axially to the upstream face 93a.

As described previously and with reference to the , the input shaft 12 comprises a radial tab 93 which extends radially towards the longitudinal axis other along the longitudinal axis X. Each radial notch 104 has a U-shaped radial section. The openings of the radial notches 104 are oriented towards the longitudinal axis on the upstream face 93a and on the downstream face 93b.

The third ring 101 is inserted from downstream at the level of the downstream end 12b of the input shaft 12. For this the radial teeth 103 of the third ring 101 each pass through a radial notch 104 so that the third ring 101 is arranged in the annular cavity 91 of the input shaft 12. The third ring 101 is pivoted along the longitudinal axis to make contact between the downstream faces 103b and the upstream face 93a of the radial tab 93. In a situation of installation, the internal peripheral edge 102a of the third ring 101 extends radially inside the peripheral annular face 105 (or free end of the radial tab 93). The downstream face 94b of the sole is intended to come into contact with the upstream face 101a of the third ring 101.

In reference to the , the second locking system 100 advantageously comprises a fourth ring 107 which is centered on the longitudinal axis entry 12. The fourth ring 107 is generally split like a circlip. The fourth ring 107 is advantageously received in an annular groove 108 of the input shaft 12 which is centered on the longitudinal axis. The annular groove 108 is arranged upstream of the upstream face 93a of the radial tab 93. More precisely, the annular groove 108 is formed in the radial tab 93. It has a U-shaped axial section and its opening opens onto the face peripheral annular ring 105 of the radial tab 93. Due to the radial notches formed in the radial tab 93, the latter is in the form of several sectors of radial tabs which comprise portions of the annular groove. In this way, the fourth ring 107 extends downstream of the third ring 101 and in the radial notches 104. The fourth ring 107 is advantageously arranged facing the downstream faces of the teeth.

Advantageously, the third ring 101 comprises means making it possible to axially immobilize the fourth ring 107. In fact, the third ring 101 advantageously comprises two prominences 106 which each extend, along the longitudinal axis downstream face 103b of a radial tooth 103 of the third ring 101. The radial teeth 103 carrying the prominences 106 are located opposite each other. In other words, these radial teeth 103 are diametrically opposed. In the present example, each prominence 106 has an L-shaped axial section.

Each prominence 106 advantageously comprises a first portion extending axially from the downstream face and a second portion extending from one end of the first portion towards the longitudinal axis X. In this way, the second portion is at a distance from the face downstream 103b of the radial tooth 103. In installation situation, when the downstream faces 103b of certain radial teeth 103 are in contact with the downstream face 93a, the prominences 106 are engaged in corresponding radial notches 104 and the fourth ring 107 is received in the space formed between the downstream face of the radial tooth 103 and the upstream face of the second portion of the prominence 106. Advantageously, but not restrictively, the prominences 106 are engaged in the respective notches after a rotation of the third ring 101.

The locking device 42 advantageously comprises a locking element 110 configured so as to immobilize the first nut 60 and the third nut 90 in position. Advantageously, but not restrictively, the locking element 110 is engaged with the first nut 60 and the second nut 73. More precisely, the locking element 110 comprises a cylindrical shape with an axis of revolution centered on the longitudinal axis.

The locking element 110 comprises first external splines 111 which engage with internal splines 112 of the first nut 60. The first external splines 111 each extend along the axis of revolution of the locking element 110 and are regularly distributed around the axis of revolution.

According to another advantageous characteristic, the locking element 110 also comprises second external splines 113 which engage with internal splines 114 of the third nut 90. The locking element 110 extends inside the shaft low pressure compressor 15. The second external grooves 113 each extend along the axis of revolution of the locking element 110 and are regularly distributed around the axis of revolution.

Advantageously, but not limited to, the first external grooves 111 and the second external grooves 113 are offset axially.

Alternatively, the locking element 110 is screwed onto a thread of the first nut 60 and the third nut 90. In this case, the locking element 110 comprises external threads cooperating respectively with internal threads of the first and second nuts .

In the present example, the locking element 110 comprises a first portion 115a and a second portion 115b which have different sections. In particular, the internal diameter of the second portion 115b is less than the internal diameter of the first portion 115a. The first and second portions 115a, 115b are separated by a shoulder 115c.

Figures 4 to 16 illustrate assembly stages of the turbomachine modules. We understand that the assembly or reassembly of the turbomachine modules can be used by repeating these operations in reverse order.

As illustrated in the , a first step of the method consists of installing the first nut 60 in the low pressure compressor shaft 15. The first nut 60 is inserted from the upstream end 15a of the low pressure compressor shaft 15. The first nut 60 is moved in translation along the longitudinal axis until at least part of the downstream annular face 62b of the flange 62 bears against the upstream annular surface 51a of the annular projection 51. The first nut 60 is of the so trapped in the low pressure compressor shaft 15.

The method includes a second step of tightening the low pressure shaft 9 on the first nut 60 (the latter being trapped in the low pressure compressor shaft 15). For this purpose, the low pressure shaft 9 is inserted into the low pressure compressor shaft 15 by sliding using the splines 50, 53. The first nut 60 makes it possible to secure the low pressure shaft 9 to the shaft low pressure compressor 15.

In Figures 5 and 6, the method comprises a third step of limitation in translation of the first nut 60. The limitation in translation is achieved thanks to the anti-displacement member 65. This step includes the engagement of the anti-displacement member movement 65 in the low pressure compressor shaft 15. The anti-displacement member 65 is moved in translation along the longitudinal axis so as to take it from a disengagement position to an engagement position with at least l low pressure compressor shaft 15. In this engagement position of the anti-displacement member 65, the teeth 68 are engaged in the notches 70 of the low pressure compressor shaft 15 and the downstream face 67b of the wing annular 67 of the anti-displacement member 65 faces the upstream annular face 62a of the flange 67 of the first nut 60. In this way, the first nut 60 cannot move along the longitudinal axis (or at least over a short distance corresponding to the axial play J1) but can still pivot. In particular, the teeth 68 make it possible at least in part to create the axial play J1 allowing the first nut 60 to rotate freely.

With reference to Figures 7 and 8, the method comprises a fourth step which consists of axially immobilizing the anti-displacement member 65. This makes it possible to maintain the anti-displacement member 65 so that it axially limits the first nut 60 in upstream. For this, this fourth step includes a sub-step of screwing the second nut 73 onto the low pressure compressor shaft 15. In this way, the second nut 73 is taken from an unscrewing position to a screwing position. This screwing step is carried out using another suitable tool (not shown) which is also inserted inside the low pressure compressor shaft. The second nut 73 is screwed until it is tightened axially against the anti-displacement member 65. In the screwing position, the internal and external threads 74, 76 are engaged and the second annular face 74b of the second nut 73 rests against the upstream face 67a of the annular wing 67 of the anti-displacement member 65. The low pressure compressor shaft 15 can no longer move backwards either, nor can the low pressure compressor (i.e. the second nut 73 ) avoids a rapprochement between the low pressure compressor and the low pressure turbine).

The method also includes a fifth step which consists of blocking the second nut 73 from rotating. For this purpose, the method comprises a sub-step in which the first locking system 77 is mounted. Advantageously, the first locking system 77 is a nut brake. Of course, other means with the same function are possible. Firstly, the first ring 78 is taken from a disengagement position to an engagement position. Passing from one position to the other, the radial teeth 82 pass axially through the slots 81 of the second nut 73 and also the radial notches 84 arranged radially outside the second nut 73. The second nut 73 is screwed by so that the slots face respectively the radial notches 84. In this way, the first ring 78 extends both through the first nut 60 and the low pressure compressor shaft 15 so that the radial teeth 84 do not can move in rotation around the longitudinal axis X. This is also possible because the external diameter of the radial teeth is greater than the external diameter of the second nut 73.

The first ring 78 extends radially around the anti-displacement member 65. Secondly, the second ring 85 is taken from a disengagement position to an engagement position as well. In the engagement position, the second ring 85 is inserted into the annular groove 87 of the second nut 73. The radial teeth are blocked axially by the second ring 85.

In reference to the , the method comprises a sixth step consisting of installing the third nut 90 on the input shaft 12. The third nut 90 is inserted from the downstream end 12b of the input shaft 12 from downstream to upstream. The third nut 90 is then found in the cavity 91 of the input shaft 12. Installation is possible due to the external diameter of the annular sole 94 which is less than the internal diameter of the input shaft 12 measured at the level of the peripheral annular face 105 of the radial tab 93.

The third nut 90 is put on hold after its insertion into the cavity 91.

With reference to Figures 11 and 12, the method comprises a seventh step of imprisoning the third nut 90 in the cavity 91. For this, the seventh step comprises a sub-step in which the third ring 101 is mounted on the shaft entry 12. The third ring 101 is taken from a disengagement position to an engagement position. By moving from one position to the other, the third ring 101 is positioned so that the radial teeth 103 pass axially through the radial notches 104. Once the third ring 101 is in the cavity 91, it is pivoted as on the so that the radial teeth 103 no longer face the radial notches 104. In the engagement position, the downstream faces 103b of the teeth face the upstream face 93a of the radial tab 93. The downstream face 94b of the third nut 90 also faces the upstream face 101a of the third ring 101 against which the latter is intended to bear. The internal diameter of the ring 101 is less than the external diameter of the annular sole 94 and the third ring 101 is intended to extend around the cylindrical body of the third nut 90. This configuration makes it possible to reduce the radial opening at the downstream end 15b of the input shaft 12 delimited by the peripheral annular face 105, which prevents the extraction of the third nut 90 downstream. The internal diameter of the third ring 101 being less than the internal diameter of the tab 93 (delimited by the annular surface 105), the contact surface with the third ring 101 is greater. The third nut 90 is enclosed or imprisoned in the cavity 91.

In reference to the , the method comprises an eighth step consisting of trapping the third ring 101 in the cavity 91. For this, the method comprises a sub-step in which the fourth ring 107 is taken from a disengagement position to an engagement position. In the engagement position, the fourth ring 107 is inserted into the annular groove 108 of the input shaft 12. The radial teeth 103b are blocked axially by the fourth ring 107. More precisely, the third ring 101 cannot be move axially downstream.

In reference to the , the method comprises a ninth step consisting of securing the input shaft 12 to the low pressure compressor shaft 15. For this, the downstream end 12b of the input shaft 12 is inserted inside the the upstream end 15a of the low pressure compressor shaft 15. The input shaft 12 is free to slide along the longitudinal axis relative to the low pressure compressor shaft 15 using the splines 47, 49. In this way, the input shaft 12 is also taken from a disengagement position to a disengagement position. In the engagement position, the splines 47, 49 are engaged and the downstream face 93b of the downstream end 12b of the input shaft 12 bears against the annular surface 86 of the low pressure compressor shaft 15 .

In reference to the , the method comprises a tenth step consisting of screwing the third nut 90. In this way the third nut 90 is taken from an unscrewing position to a screwing position. This screwing step is carried out using a suitable tool (not shown) which is also inserted inside the input shaft 12 of the speed reducer 3 from upstream. The third nut 90 is screwed until it is tightened axially against the third ring 101. In the screwing position, the external thread 95 of the third nut 90 is engaged with the internal thread 72 of the anti-displacement member 65. Likewise, in the screwing position, the downstream face 94b of the third nut 90 bears against the upstream face 101a of the third ring 101.

Finally, the method comprises an eleventh step consisting of engaging the locking element 110. The locking element 110 is taken from a disengagement position to an engagement position. The locking element 110 is previously inserted into the low pressure compressor shaft from upstream and from the input shaft 12. The engagement step is carried out using a suitable tool (not shown) which is also inserted inside the input shaft 12 from upstream. In the engaged position, the first outer splines of the locking member 110 are engaged with the inner splines 112 of the first nut 60 and the second outer splines 113 of the locking member 110 are engaged with the inner splines 114 of the third nut 90. The locking element 110 prevents loosening or unscrewing of the first and second nuts.

With such a configuration, it is possible to disassemble and mount only the input shaft 12 of the speed reducer 3 while maintaining the other shafts of the modules in the mounted position. The different nuts 60, 73, 90 and the members (rings, anti-displacement member and locking elements) are tightened on each other to perform, on the one hand, anti-rotation functions and on the other hand, anti-axial displacement functions.

The low pressure compressor shaft 15 is independent of the input shaft 12 and the low pressure shaft 9. By dismantling the input shaft 12, the low pressure shaft 9 remains integral with the compressor shaft. low pressure compressor 15 via the first nut 60, the anti-displacement member 65 and the second nut 73.

Claims (15)

Turbomachine (1), in particular for aircraft, the turbomachine (1) having a longitudinal axis (X) and comprising:
- a first module (11) comprising a speed reducer (3) which comprises an input shaft (12) centered on the longitudinal axis (X),
- a second module (14) comprising a low pressure compressor (4), the second module (14) being connected to the first module (11),
- a third module (16) comprising a low pressure shaft (9) which is centered on the longitudinal axis X, the low pressure shaft (9) comprising an upstream end (9a) connected to the input shaft (12 ), And
- a blocking device (42) configured so as to axially immobilize the third module (16) relative to the first module (11),
characterized in that the blocking device (42) is configured so as to axially immobilize the second module (14) relative to the first module (11) and the third module (14) and comprises:
- a first nut (60) which is screwed onto a thread of the upstream end (9a) of the low pressure shaft (9) and rests against an annular projection (51) of the second module (14),
- an anti-displacement member (65) which is configured so as to axially limit the movement of the first nut (60),
- a second nut (73) which is screwed onto a thread of the second module (14) and which is configured so as to axially immobilize the anti-displacement member (65), and
- a third nut (93) which is screwed onto the anti-displacement member (65). Turbomachine according to the preceding claim, characterized in that the locking device (42) comprises a locking element (110) cooperating with the first nut (60) and the third nut (90). Turbomachine (10) according to one of the preceding claims, characterized in that the first nut (60) is mounted to rotate freely around the longitudinal axis (X). Turbomachine (1) according to one of the preceding claims, characterized in that the second module (14) comprises a low pressure compressor shaft (15) which is connected to the low pressure compressor (4) and which is centered on the axis longitudinal (X), the low pressure compressor shaft (15) being connected to the input shaft (12) and the low pressure shaft (9). Turbomachine (1) according to the preceding claim, characterized in that the low pressure compressor shaft (15) comprises the annular projection (51) and the first nut (60) has a downstream face (62b) bearing against an upstream face (51a) of the annular projection (51). Turbomachine (1) according to one of claims 4 and 5, characterized in that the anti-displacement member (65) comprises a plurality of teeth (68) each intended to engage in a notch (70) of the low pressure compressor shaft (15). Turbomachine (1) according to the preceding claim, characterized in that the plurality of teeth (68) has an external diameter greater than an external diameter of a flange (62) of the first nut (60). Turbomachine (1) according to any one of the preceding claims, characterized in that the second nut (73) is intended to be blocked in rotation by a first blocking system (77). Turbomachine (1) according to claims 4 and 8, characterized in that the first blocking system (77) comprises:
- a first ring (78), centered on the longitudinal axis (X) and intended to bear against a radial annular face (74a) of the second nut (73), the first ring (78) comprising a plurality of radial teeth (82) each intended to engage in a radial notch (84) of the low pressure compressor shaft (15), and
- a second ring (85), centered on the longitudinal axis (X) and received in an annular groove (87) of the second nut (73), the annular groove (87) being arranged upstream of the radial annular face (74a ). Turbomachine according to one of the preceding claims, characterized in that it comprises a second locking system (100) configured so as to enclose the third nut (90) in an annular cavity (91) of the input shaft ( 12). Turbomachine (1) according to the preceding claim, characterized in that the second blocking system (100) comprises:
- a third ring (101), centered on the longitudinal axis (X), and comprising a plurality of radial teeth (103) which have downstream faces (103b) intended to bear against an annular face (93a) of the the input shaft (12), the third ring (101) comprising an upstream face (101a) against which a downstream face (94b) of the third nut (90) abuts, and
- a fourth ring (107), centered on the longitudinal axis (X), received in an annular groove (108) of the input shaft (12), the fourth ring (107) facing the downstream faces ( 103b) radial teeth (103). Turbomachine (1) according to any one of the preceding claims, characterized in that the first module (11) comprises a fan (2) which is connected to a fan shaft (13) and which is arranged upstream of the second module ( 14), the low pressure shaft (9) rotating the fan shaft (13) via the speed reducer (3). Turbomachine (10) according to claim 12, characterized in that the fan (2) is ducted. Method of assembling a turbomachine according to one of the preceding claims, characterized in that it comprises the steps of:
- screwing the first nut (60) onto the low pressure shaft (9),
- limitation in translation of the first nut (60) on the low pressure compressor shaft (15) along the longitudinal axis by means of the anti-displacement member (65),
- axial immobilization of the anti-displacement member (65) by means of the second nut (73),
- screwing the third nut (90) onto the anti-displacement member (65). Method according to claim 14, characterized in that it comprises a step of engaging a locking element (110) on the third nut (90) and on the first nut (60).