Turbojet engine equipped with an electrical machine comprising several electrical modules of different diameters

Abstract

The invention relates to a turbojet engine (1) extending along a longitudinal axis (AX), and comprising an electrical machine (52), characterized in that: – this electrical machine (52) comprises several adjacent modules (M1, M2) along the longitudinal axis (AX), each module (M1, M2) comprising a portion of a concentric rotor (R1, R2) and a portion of a concentric stator (S1, S2) jointly defining an air gap (E1, E2) of revolution; – the air gaps (E1, E2) of two adjacent modules (M1, M2) have different diameters; – the portions of rotors (R1, R2) and are part of a rotor (41) of the turbojet engine (1) which is rotationally linked to a low-pressure body (9) of this turbojet engine (1); – Each stator segment (S1, S2) is equipped with windings (B1, B2); the windings (B1, B2) of the different stator segments (S1, S2) are wired together. See Figure 2 for abbreviations.

Description

Title of the invention: Turbojet engine equipped with an electric machine comprising several electric modules of different diameters Technical field

[0001] The invention relates to the integration of an electrical machine, which may be for example an alternator or a motor, in a turbojet. STATE OF THE PRIOR ART

[0002] In particular, given the recent boom in electrically powered systems, the aeronautical field is studying the integration of one or more electrical machines within a turbojet engine, to design a hybrid engine solution. Such a solution aims to use fossil fuel energy and electrical energy to drive the propulsion part of the engine and to electrically power certain functions of the engine and / or the aircraft that this engine equips.

[0003] In practice, such integration encounters multiple problems. The compactness of the arrangement of the components present within existing engines leaves little space for the addition of an electric machine. The question of the maintenance of the electric machine requires ensuring that this electric machine is easily accessible, that is to say that it is possible to intervene on this machine without having to dismantle too large a quantity of components.

[0004] Different integration solutions have been considered, but they require either significantly modifying the general structure of the engine, or reducing the dimensions of the electrical machine that can be integrated, which reduces the electrical power that can be carried.

[0005] In this context, the aim of the invention is to provide a solution making it possible to integrate an electric machine into a motor while minimizing the modifications to be made to this motor. Statement of the invention

[0006] To this end, the invention relates to a turbojet extending along a longitudinal axis, and comprising an electric machine, characterized in that:

[0007] - this electric machine comprises several adjacent modules along the long axis horizontal, each module comprising a portion of electric rotor and a portion of electric concentric stator jointly delimiting a revolution air gap;

[0008] - the air gaps of two adjacent modules have different diameters;

[0009] - the rotor portions are part of a rotor rotatably connected to a low pressure body of the turbojet;

[0010] - each portion of the electric stator is provided with windings, and the windings of the different stator portions being electrically connected to each other in the stator.

[0011] Thanks to the invention, the different diameters of the rotor portions allow the electric machine to occupy in an optimized manner an internal space of complex shape such as a conical or other shape of the turbojet, in an optimized manner to produce or receive maximum electrical power. The invention thus makes it possible to make the best use of the space available for the integration of an electric machine.

[0012] The invention also relates to a turbojet engine thus defined, comprising:

[0013] - an inlet casing extending upstream of a low pressure compressor of the turbo reactor;

[0014] - a fixed cone carried by the inlet casing and extending upstream of this inlet casing

[0015] and in which:

[0016] - the electrical stator portions are carried by the fixed cone;

[0017] - the electric rotor portions extend inside the fixed cone while being surrounded by the stator portions.

[0018] The invention also relates to a turbojet engine thus defined, in which the rotor comprises a downstream end engaged in a tubular part of the low pressure body while being linked in rotation to the low pressure body by a grooved connection.

[0019] The invention also relates to a turbojet engine thus defined, comprising a tie rod carried by a cover screwed into a thread in the tubular part, in which the downstream end of the rotor comprises a bottom crossed by this tie rod, and in which the downstream end of the rotor is retained axially by a nut screwed onto the tie rod.

[0020] The invention also relates to a turbojet engine thus defined, in which the fixed cone comprises studs by which it is fixed to the inlet casing, each stud passing through an upstream wall of the inlet casing.

[0021] The invention also relates to a turbojet engine thus defined, comprising:

[0022] - an intermediate casing extending downstream of a low pressure compressor of this turbojet

[0023] - a middle bearing carried by the intermediate casing and extending in a ra- region internal dialing of the low pressure compressor to carry an upstream part of the low pressure body;

[0024] and in which:

[0025] - the electrical stator portions are carried by the intermediate casing;

[0026] - the electric rotor portions surround the stator portions and are carried by a rotating body rigidly connected to the low pressure body.

[0027] The invention also relates to a turbojet engine thus defined, in which the electrical stator portions are part of a stator carrying at least one bearing for guiding the rotation of the low pressure body.

[0028] The invention also relates to a turbojet engine thus defined, comprising at least three modules, delimiting three air gaps of revolution, these air gaps having different diameters which increase from upstream to downstream of the turbojet engine.

[0029] The invention also relates to a turbojet engine thus defined, in which the stator and the casing to which this stator is fixed are equipped with electrical pin connectors for connecting the windings of the stator to the turbojet engine.

[0030] The invention also relates to a turbojet engine thus defined, in which the stator comprises oil circulation channels, and in which the stator and the casing to which this stator is fixed are equipped with quick connectors for connecting the channels of the stator to the turbojet engine. Brief description of the drawings

[0031] [Fig.l] is a longitudinal sectional view of a turbojet engine according to the invention;

[0032] [Fig. 2] is a partial longitudinal sectional view showing the fixed cone of a tur borejet according to a first embodiment of the invention;

[0033] [Fig. 3] is a partial longitudinal sectional view showing the attachment of the downstream part of the fixed cone to the inlet casing in a reactor according to the first embodiment of the invention;

[0034] [Fig.4] is a longitudinal sectional view showing the integration of an electrical machine at the level of an intermediate casing of a turbojet engine in accordance with the second embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] In [Fig.l], a turbojet 1 extending along an axis of rotation AX comprises at its upstream end AM an inlet sleeve through which the air is admitted to pass through a low pressure compressor 2 before being split into a central primary flow F1 and a secondary flow F2 surrounding the primary flow.

[0036] These flows circulate in the turbojet 1 from upstream AM to downstream AV, this turbojet being delimited externally by a fairing 3 which externally delimits the secondary flow F2.

[0037] The primary flow is then compressed in a high-pressure compressor 4 before arriving in a combustion chamber 5, after which it is expanded through a high-pressure turbine 6 and a low-pressure turbine 7 before being discharged to the rear. The secondary flow is directed directly to the rear.

[0038] As can be seen in [Fig.l], the low pressure compressor 2 and the low pressure turbine 7 comprise moving blades carried by a rotating assembly constituting a low pressure body 9. Similarly, the high pressure compressor 4 and the high pressure turbine 6 comprises moving blades carried by the same high pressure body 11, which surrounds the low pressure body while being independent in rotation thereof, these two bodies rotating around a longitudinal axis AX.

[0039] This engine comprises upstream of the low pressure compressor 2 an inlet casing 12, comprising radial arms marked 13 in [Fig.2], by which it is secured to structural elements of the fairing 3. An upstream bearing 14 mounted in this inlet casing 12 carries in rotation an upstream part of the low pressure body 9.

[0040] It also comprises an exhaust casing 16 located downstream of the low pressure turbine and secured to the fairing 3 by radial arms, in which is mounted a downstream bearing 17 rotating a downstream part of the low pressure body.

[0041] Similarly, an intermediate casing 18 (inter-compressor casing) is located between the compressors and secured to the fairing 3 by other radial arms, and a middle bearing 19 is mounted in this intermediate casing 18 to rotate a middle portion of the low-pressure body. Another bearing 21 mounted in this intermediate casing 18 carries in rotation an upstream end of the high-pressure body 11. The downstream end of the high-pressure body 11 is itself carried in rotation by an additional inter-shaft bearing 22 which is interposed between the low-pressure body 9 and the high-pressure body 11. 1st embodiment

[0042] This inlet casing 12 is extended upstream by a fixed cone 23, directing the incoming flow around the central part comprising the high and low pressure bodies, minimizing the induced aerodynamic losses.

[0043] As can be seen more clearly in [Fig. 2], the bearing 14 which extends into the inlet casing 12 to which it is fixed comprises structural elements 24 carrying an outer ring of a ball bearing 26 whose inner ring surrounds and encloses a tubular part 27 of an upstream portion 28 of the low pressure body 9, to guide in rotation and maintain the upstream portion 28 of the low pressure body 9.

[0044] This tubular part 27 advantageously forms part of the disc carrying the first blades of the low pressure compressor 2, that is to say the first compressor disc, this low pressure compressor being similar here to a fan.

[0045] The upstream portion 28 corresponds for example to an extension of the disc of the low pressure body 9 which carries the first row of moving blades of the low pressure compressor 2 of the engine.

[0046] As can be seen more clearly in [Fig. 3], a sealing barrier 29 located upstream of the bearing 26 comprises an attached crown 31 surrounding the tubular part 27 while being rigidly secured to it, cooperating with a seal 32 whose internal face runs along the external face of the crown 31 to ensure controlled sealing upstream of the bearing 26 carried by the bearing 14.

[0047] An internal cover 34 is screwed into a thread 36 formed on the internal face of the part 27, being located along the axis AX downstream of the bearing 26, to close this tubular part 27.

[0048] This internal cover 34 comprises a threaded rod constituting a tie rod 37 protruding from its upstream face to extend inside the part 27 towards the upstream. This tie rod 37 comprises at its free end a flat 38 allowing a tool to be engaged on this end to pivot the tie rod with the cover in order to screw it into the thread 36 to mount this cover in the tubular part 27.

[0049] The tubular part 27 receives a downstream end 39 of an electric machine rotor 41. This downstream end 39 has a tubular shape, with an external diameter close to the internal diameter of the part 27, and comprises a bottom 42 provided with a central hole capable of receiving the tie rod 37.

[0050] When it is in place in the part 27, the downstream end 39 is immobilized in rotation relative to the part 27 by a grooved connection 43 comprising external grooves of the end 39 engaging longitudinally in internal grooves of the part 27.

[0051] Additionally, a stud 44 passes through a corresponding through hole in the bottom 42 and engages in a blind hole in the cover, to also prevent the cover from rotating relative to the end 39.

[0052] The axial locking of the rotor 41 relative to the part 27 is ensured by engaging a nut 46 around the threaded tie rod 37, and tightening it, so that it is immobilized relative to the cover, and thereby relative to the part 27 of the low pressure body 9. The nut 46 is advantageously of the self-locking type.

[0053] As visible in [Fig.2], the rotor 41 which extends upstream of the bearing 14 comprises a first portion of electric rotor RI extended axially by a second portion of electric rotor R2 of larger diameter than the first, this second portion R2 being extended axially by the downstream end 39 by which this rotor 41 is rigidly secured to the tubular part 27.

[0054] More particularly, this rotor 41 is formed of a tubular body 47 carrying on its external face first magnets A1 at the level of the first portion of electric rotor RI, and second magnets A2 at the level of the second portion of electric rotor R2.

[0055] This rotor 41 is capped by the fixed cone 23 which comprises a sleeve 48 flared towards the downstream end, integrating a stator 49, and a cover 51 closing the upstream end of this sleeve 48. The stator 49 comprises a first stator portion SI, which is closed at its upstream end by the cover 51, and which is extended towards the downstream end by a second stator portion S2 rigidly secured to the input casing 12.

[0056] The first stator portion SI surrounds the first rotor portion RI in a de limiting therewith a first air gap El having a shape of revolution, to form a first module Ml of electric machine. Similarly, the second stator portion S2 surrounds the second rotor portion R2 by delimiting therewith a second air gap E2 of revolution, to constitute a second module M2 of electric machine.

[0057] The first stator portion S1 and the second stator portion S2 comprise windings B1, B2 which are wired in common, that is to say that the windings of the different modules are electrically connected to each other in the stator 49. The modules M1 and M2 thus jointly form a single electrical machine 52 having for example a single set of electrical terminals carried by the stator.

[0058] As visible in [Fig. 2], the tubular body 47 has a larger diameter at the second rotor portion R2 than at the first rotor portion RL. Similarly, the internal diameter of the sleeve 48 which integrates the stator 49 is larger at the second rotor portion R2 than at the first rotor portion RL.

[0059] The diameter d2 of the air gap E2 is thus greater than the diameter dl of the air gap El, so that in general, the diameter of the module M2 is greater than that of the module ML. The air gaps El and E2 thus have diameters which increase from upstream to downstream along the axis AX. This makes it possible to best occupy the internal space delimited by the fixed cone 23 in order to maximize the power of the electrical machine while allowing the mounting and dismounting of this fixed cone 23 when the rotor 41 is in place.

[0060] The cone 23 which corresponds to the stator of the electrical machine is fixed to an upstream face of the input casing 12 by several studs 53 uniformly distributed at the level of the downstream edge 56 of the sleeve 48 from which these studs 53 protrude axially.

[0061] Each stud 53 passes through a corresponding hole formed in an upstream wall 57 of the inlet casing 12 against which the downstream edge 56 of the sleeve 48 is applied. A nut 54 is screwed and tightened onto the end of each stud 53 to clamp the wall 57 between this nut 54 and the edge 56.

[0062] Under these conditions, the stator of the electrical machine, that is to say the fixed cone 23 can be completely dismantled by unscrewing the nuts 54, to then extract this cone by moving it axially away from the input casing.

[0063] Similarly, the rotor 41 of the electrical machine can then be removed, by loosening and removing the nut 46 from the tie rod 37, before extracting the rotor causing it to slide axially in the part 27 to move it away from the input casing 12.

[0064] The arrangement according to the invention thus makes it possible to easily intervene on the electrical machine for a maintenance operation, since it makes it possible to dismantle the stator and the rotor independently, without dismantling any other part of the motor: the machine The electric system constitutes a unit that is substantially independent of the rest of the engine in terms of maintenance.

[0065] Furthermore, it remains possible to access the internal region of the low pressure body, since the cover carrying the threaded tie rod 37 is removable, so that it can be removed to pass a tool inside the low pressure body, through the tubular part 27.

[0066] Furthermore, in the example of figures 2 and 3 the electric machine comprises two modules, but it could comprise three, four or any other number. 2nd embodiment

[0067] According to a variant shown in [Fig.4], the machine is integrated into a motor without a fixed cone, comprising a fan. In this case, the electrical machine 52 is integrated into the radially internal region of the low pressure compressor 2, in which the middle bearing 19 is installed, held by the intermediate casing 18 to which it is rigidly secured, to rotate an upstream portion of the low pressure body 9. This middle bearing 19 here comprises a ball bearing 26 located upstream and a roller bearing 58 located downstream of the bearing 26.

[0068] This bearing 19 comprises a hollow stator 49 rigidly secured to the casing 18, this stator 49 extending upstream into the radially internal space of the compressor 2. This stator 49 carries the external rings of the two bearings 26 and 58 which guide the low pressure body 9 in rotation.

[0069] The stator 49 is surrounded by a rotating body 59 rigidly secured to the upstream end of the low-pressure body 9 by a rigid connection 61. This rotating body 59 carries fan blades 62 at its upstream end, and the moving blades 63 of the low-pressure compressor 2 in its central portion which extends around the stator 49. The compressor 2 also comprises fixed blades which are carried by a low-pressure stator 64 whose downstream end is rigidly secured to the casing 18.

[0070] As visible in [Fig.4], the stator 49 comprises a first electric stator portion SI extended axially downstream by a second electric stator portion S2 of larger diameter than the first, this second portion S2 being itself extended downstream by a third electric stator portion S3 having an even larger diameter. This stator 49 which is rigidly secured to the casing 18 at the downstream end of its third stator portion S3, thus constitutes both a bearing support and an electric stator.

[0071] The first stator portion S1, the second stator portion S2, and the third stator portion S3 comprise electrical windings identified respectively by B1, B2 and B3.

[0072] This stator 49 is surrounded by the rotating body 59 which comprises a rotor 41 comprising a first portion of electric rotor RI extended downstream by a second portion of electric rotor R2 which is itself extended downstream by a third portion of electric rotor R3, these three rotor portions being rigidly secured to the rotating body 59.

[0073] The first rotor portion RI surrounds the first stator portion SI, delimiting therewith a first air gap El having a shape of revolution, to form a first module Ml of electric machine.

[0074] Similarly, the second rotor portion R2 surrounds the second stator portion S2, delimiting therewith a second air gap E2 of revolution, to constitute a second module M2 of electric machine. In the same way, the third rotor portion R3 surrounds the third stator portion S3, delimiting therewith a third air gap E3 of revolution, to constitute a third module M3 of electric machine.

[0075] This rotor 41 comprises first magnets A1 at the level of the first rotor portion RI, second magnets A2 at the level of the second rotor portion R2, and third magnets A3 at the level of the third rotor portion R3, these magnets thus being radially opposite the corresponding windings of the stator 49.

[0076] As seen in [Fig. 4], the stator 49 has a larger external diameter at the second stator portion S2 than at the first stator portion S1, and an even larger external diameter at the third stator portion S3. Similarly, the internal diameter of the rotor 41 is larger at the second rotor portion R2 than at the first rotor portion R1, and it is even larger at the third rotor portion R3.

[0077] The diameter d2 of the air gap E2 is thus greater than the diameter dl of the air gap El, so that in general, the diameter of the module M2 is greater than that of the module ML. In the same way, the diameter d3 of the air gap E3 is greater than the diameter d2 of the air gap E2. The air gaps El, E2 and E3 thus have diameters which increase from upstream to downstream along the axis AX, which facilitates the assembly and disassembly of the electrical machine.

[0078] This makes it possible to best occupy the internal space delimited by the compressor 2 in order to maximize the power of the electric machine while allowing assembly and disassembly in this internal space.

[0079] The windings B1, B2 and B3 are wired in a common manner, that is to say that these windings are connected to each other in the stator 49. These modules M1, M2 and M3 thus jointly form a single electrical machine 52, having for example the same set of electrical terminals carried by its stator.

[0080] Furthermore, in the example of [Fig.4], the electrical machine has three modules, but it could have two, four or any other number. Electrical connections

[0081] Generally speaking, the winding(s) of the electrical machine are connected by means of power cables through the wall 57 of the input casing 12 to power cables extending inside the radial arms 13 in the case of the first embodiment.

[0082] The connection of the cables is advantageously ensured with pin connectors. For example, the male connector is carried by the downstream edge of the cone 23, and the female connector is carried by the wall 57, at a connection region R corresponding to the support zone of the edge 56 on the wall 57, and these two connectors extend parallel to the longitudinal direction AX. Under these conditions, when the fixed cone 23 is dismantled, when it is moved away from the input casing 12 this causes its electrical disconnection. Similarly, when it is mounted, its fitting onto the wall 57 is sufficient to connect it electrically.

[0083] In the case of the second embodiment, it is through a wall of the intermediate casing that they are connected to power cables in the same way, that is to say by means of pin connectors. Cooling

[0084] Furthermore, the stator 49 advantageously comprises internal hydraulic channels allowing oil, or another fluid, to circulate therein to cool the electrical machine: the continuous assembly of the stator portions within the stator 49 makes it possible to provide a cooling circuit common to the different stator portions.

[0085] Similarly, these hydraulic channels are then connected to hydraulic supply channels or conduits carried by the inlet casing 12 (or by the intermediate casing 18), by means of quick connectors. Benefits

[0086] By implementing an electric machine comprising several modules having different diameters, the invention makes it possible to optimize the space available for the integration of an electric machine.

[0087] The integration of the electric machine at the level of the inlet cone or the intermediate bearing allows it to be linked in rotation to the low pressure compressor, which corresponds to a cold zone which is therefore favorable to its cooling.

[0088] More generally, the invention can thus be applied to the integration of an electrical machine at the level of the inlet cone, the downstream cone or even a bearing support of the turbojet.

[0089] The choice of a single stator bringing together the different stator portions makes it possible to optimize the cooling of the stator elements thanks to a common cooling circuit which can have a higher flow rate.

Claims

Claims

1. Turbojet engine (1) extending along a longitudinal axis (AX), and comprising an electric machine (52), characterized in that: - this electric machine (52) comprises several modules (Ml, M2, M3) adjacent along the longitudinal axis (AX), each module (Ml, M2, M3) comprising a portion of electric rotor (RI, R2, R3) and a portion of electric stator (SI, S2, S3) concentric jointly delimiting an air gap (El, E2, E3) of revolution; - the air gaps (El, E2, E3) of two adjacent modules (Ml, M2, M2) have different diameters; - the portions of electric rotors (RI, R2, R3) are part of a rotor (41) linked in rotation to a low pressure body (9) of the turbojet engine (1); - each electrical stator portion (SI, S2, S3) is provided with windings (Bl, B2, B3), and the windings (Bl, B2, B3) of the different stator portions (SI, S2, S3) being electrically connected to each other in the stator (49).

2. Turbojet (1) according to claim 1, comprising: - an inlet casing (12) extending upstream of a low pressure compressor (2) of the turbojet (1); - a fixed cone (23) carried by the inlet casing (12) and extending upstream of this inlet casing (12); and in which: - the electrical stator portions (SI, S2) are carried by the fixed cone (23); - the electrical rotor portions (RI, R2) extend inside the fixed cone (23) while being surrounded by the stator portions (SI, S2).

3. Turbojet (1) according to claim 2, in which the rotor (41) comprises a downstream end (39) engaged in a tubular part (27) of the low pressure body (9) while being linked in rotation to the low pressure body (9) by a grooved connection (43).

4. Turbojet (1) according to claim 3, comprising a tie rod (37) carried by a cover screwed into a thread (36) of the tubular part (27), in which the downstream end (39) of the rotor comprises a bottom (42) crossed by this tie rod (37), and in which the downstream end (39) of the rotor is retained axially by a nut (46) screwed onto the tie rod (37).

5. Turbojet (1) according to claim 3, in which the fixed cone (23) comprises studs (53) by which it is fixed to the inlet casing (12), each stud (53) passing through an upstream wall (57) of the inlet casing (12).

6. Turbojet (1) according to claim 1, comprising: - an intermediate casing (18) extending downstream of a low pressure compressor (2) of this turbojet (1) - a middle bearing (19) carried by the intermediate casing (18) and extending in a radially internal region of the low pressure compressor (2) to carry an upstream part of the low pressure body (9); and in which: - the electrical stator portions (SI, S2, S3) are carried by the intermediate casing (18); - the electrical rotor portions (RI, R2, R3) surround the stator portions (SI, S2, S3) and are carried by a rotating body (59) rigidly connected to the low pressure body (9).

7. Turbojet according to claim 6, in which the electrical stator portions are part of a stator (49) carrying at least one bearing (26, 58) for guiding the rotation of the low pressure body (9).

8. Turbojet (1) according to claim 1, comprising at least three modules (Ml, M2, M3), delimiting three air gaps (El, E2, E3) of revolution, these air gaps (El, E2, E3) having different diameters which increase from upstream (AM) to downstream (AV) of the turbojet (1).

9. Turbojet (1) according to one of claims 2 to 8, in which the stator (49) and the casing (12, 18) to which this stator (49) is fixed are equipped with electrical pin connectors for connecting the windings of the stator (49) to the turbojet (1).

10. Turbojet (1) according to one of claims 2 to 9, in which the stator (49) comprises oil circulation channels, and in which the stator (49) and the casing (12, 18) to which this stator is fixed are equipped with quick connectors for connecting the channels of the stator (49) to the turbojet (1).

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