AIRCRAFT TURBOMACHINE ASSEMBLY INCLUDING AN IMPROVED DEVICE FOR ATTACHING AN EJECTION CONE

Abstract

The invention relates to an aircraft turbomachine assembly, comprising a first turbomachine part (54) and a second turbomachine part (56) located downstream of the first part, the first and second parts (54, 56) being centered on a longitudinal axis (3), the second part (56) corresponding to all or part of a turbomachine exhaust cone, the assembly including a fastening device (58) for attaching the first part to the second part. According to the invention, the fastening device (58) is configured so as to allow the first and second turbomachine parts (54, 56) to move from a position uncoupled axially to a position of axial coupling by rotating one relative to the other about the longitudinal axis (3). Figure 3.

Description

Title of the invention: AIRCRAFT TURBOMACHINE ASSEMBLY COMPRISING AN IMPROVED DEVICE FOR ATTACHING A GAS EJECTION CONE technical field

[0001] The invention relates to the field of aircraft turbomachinery, and more specifically to the mounting of a gas ejection cone within a turbomachine.

[0002] The invention applies in particular to turbojet engines, and even more particularly to twin-spool, twin-flow turbojet engines. PRIOR TECHNOLOGY

[0003] In the prior art, it is known to implant a gas ejection cone at the rear of an aircraft turbomachine. This cone corresponds to an exhaust system, also known by the English term "plug". Such a cone has a general shape of revolution, with its rear part having a cross-section that decreases towards the downstream end, hence its name of cone.

[0004] The gas ejection cone is generally mounted on a structural part of the turbomachine, such as the turbine rear casing. Its mounting must be reversible, so that it can be removed and provide access to the inside of the turbomachine, particularly for maintenance operations.

[0005] Furthermore, the cone can be made in two separate pieces, arranged axially in continuity with each other. These two pieces are then mounted one on top of the other, using a fastening device.

[0006] Whether for mounting the cone on the turbomachine or for mounting one of the two cone parts onto the other part, a fastening device in the form of an annular row of bolts is generally used. The bolts, provided in a very large number, then pass through two mounting flanges respectively provided on the two parts, in order to secure them together.

[0007] While this annular row of bolts is mechanically sound, it can still be improved. Firstly, it involves particularly long, and therefore costly, assembly and disassembly times. Costs are also affected by the fact that such an assembly usually requires at least two operators: one to hold the gas ejection cone in place, and the other to assemble the bolts.

[0008] The high number of bolts also affects the mass of this part of the turbomachine, and therefore increases fuel consumption. This increase This is exacerbated by the fact that these bolts, in addition to being unsightly, generate aerodynamic losses at the outer surface of the gas ejection cone. Description of the invention

[0009] To overcome the drawbacks mentioned above relating to prior art, the invention first relates to an assembly for an aircraft turbomachine, comprising a first turbomachine component and a second turbomachine component located downstream of the first component. The first and second components extend around a longitudinal axis, preferably the longitudinal axis of the turbomachine, and these components are preferably annular, and also preferably both centered on this same axis. The second component corresponds to all or part of a turbomachine exhaust cone, the assembly comprising a device for attaching the first component to the second component.

[0010] According to the invention, the fastening device is configured so as to allow the first and second turbomachine parts to move from a position not axially coupled to each other, to an axially coupled position, by rotation of one relative to the other along the longitudinal axis.

[0011] The invention thus breaks with the same technology used for decades for the assembly of the gas ejection cone, by providing an axial coupling by simple relative rotation of the parts concerned, around the longitudinal axis of the turbomachine.

[0012] This solution is advantageous because it is easy and quick to implement, and inexpensive. In particular, it does not require multiple operators. Due to the elimination or drastic reduction of bolts or similar components, it also generates less aerodynamic drag and less mass. The invention therefore represents a result of technological research aimed at significantly improving aircraft performance and, in this respect, contributes to reducing the environmental impact of these aircraft (decarbonization).

[0013] The invention also has at least one of the following optional features, taken individually or in combination.

[0014] Preferably, the assembly comprises at least one locking element for the first and second turbomachine parts in their axial coupling position, each locking element being arranged to prevent the second part from rotating relative to the first part along the longitudinal axis, each locking element preferably being a screw. Of course, the number of these locking elements can be significantly reduced compared to the number of bolts used. work in conventional solutions of the prior art. As an example, the number of these locking elements can be reduced to a value between three and six, for example four elements arranged at 90° to each other.

[0015] Preferably, the assembly is configured so that each locking member is mounted on the assembly from the outside of it, each locking member preferably having an orientation with a non-zero radial component, and even more preferably a radial orientation, or substantially radial, or orthogonal or substantially orthogonal locally to an aerodynamic surface defined externally by the first part and / or the second turbomachine part.

[0016] According to a first configuration, the second turbomachine part is a second part of the gas ejection cone, and the first turbomachine part is a first part of the gas ejection cone, arranged upstream of the second part.

[0017] According to a second configuration, the second turbomachine component forms the entire exhaust cone, and the first turbomachine component is a turbomachine housing, preferably a rear turbine housing. However, in this second configuration, the second turbomachine component, which forms the entire exhaust cone, can itself be made of several parts.

[0018] Preferably, the fastening device comprises a first fastening flange belonging to the first part, and a second fastening flange cooperating with the first fastening flange, and belonging to the second part.

[0019] According to a first preferred embodiment of the invention, the first flange comprises, alternately along a circumferential direction of the assembly, first axial openings and first axial stop members projecting radially, and the second flange comprises, alternately along the circumferential direction of the assembly, second axial openings and second axial stop members projecting radially, the fastening device being configured so as to first bring the first and second parts into their uncoupled axial position by inserting the first stop members into the second axial openings and the second stop members into the first axial openings, and then to bring the first and second parts into their axially coupled position by rotating one relative to the other along the longitudinal axis.leading the first and second axial thrust bearings to cooperate with each other.

[0020] Preferably, the first axial stop members project radially inwards, and the second axial stop members project radially outwards. However, a reverse configuration could be adopted without departing from the scope of the invention.

[0021] Preferably, the first fixing flange includes, associated with one of the first axial openings, an opening bottom forming an axial stop for one of the second axial stop members, when bringing the first and second parts into their axially uncoupled position.

[0022] Preferably, the first and second fixing flanges have circumferential stop means, configured to stop the relative rotation between the first and second parts, when bringing these parts into their axial coupling position.

[0023] According to a second preferred embodiment of the invention, one of the first and second fixing flanges comprises pins spaced circumferentially from each other, each pin preferably extending in a direction with a non-zero radial component, and the other of the first and second fixing flanges comprises notches spaced circumferentially from each other, each notch comprising an axial portion open axially at one of its two opposite ends, as well as a circumferential portion initiated from the other of the two opposite ends of the axial portion.

[0024] According to a third preferred embodiment of the invention, one of the first and second fixing flanges comprises pins spaced circumferentially from each other, each pin preferably extending axially and having an enlarged distal end, and the other of the first and second fixing flanges comprises lights spaced circumferentially from each other, each light having an enlarged circumferential end.

[0025] According to a fourth preferred embodiment of the invention, the first and second fixing flanges form a helical connection, centered on the longitudinal axis.

[0026] The invention also relates to an aircraft turbomachine, comprising an assembly as described above. Preferably, this is a turbojet engine, and even more preferably a twin-spool, twin-flow turbojet engine. Other types of turbomachines, such as turboprop engines, remain conceivable, however, without departing from the scope of the invention.

[0027] Finally, the invention relates to a method of assembling such an assembly for an aircraft turbomachine, the method comprising a step of moving the first and second parts from their position not axially coupled to each other, to their axially coupled position, by rotating one relative to the other along the longitudinal axis.

[0028] Other advantages and features of the invention will appear in the detailed, non-limiting description below. Brief description of the drawings

[0029] This description will be made with reference to the attached drawings, among which;

[0030] [Fig.1] represents a schematic longitudinal cross-sectional view of a turbojet engine according to the invention;

[0031] [Fig.2] represents a schematic perspective view of the turbojet engine shown in [Fig.1], equipped with its nacelle;

[0032] [Fig.3] represents an enlarged perspective view of two constituent parts of a gas ejection cone equipping the turbojet shown in the previous figure, the two parts being in an unassembled position;

[0033] [Fig.4] represents an enlarged perspective view of the fixing flange equipping one of the two parts shown in the previous figure, referred to as the second part;

[0034] [Fig.5] represents a cross-sectional view taken along plane PI of [Fig.4];

[0035] [Fig.6] represents a cross-sectional view taken along plane P2 of [Fig.4];

[0036] [Fig.7] shows an enlarged perspective view of the mounting flange equipping the other of the two pieces shown on the [Fig.3], called first piece, cut in a plane P3 of the [Fig.3];

[0037] [Fig.8] represents a view similar to the previous one, with the fixing flange shown cut in a plane P4 of [Fig.3];

[0038] [Fig.9]

[0039] [Fig. 10]

[0040] [Fig. 11] are perspective views schematically illustrating a first step in mounting the second cone piece onto the first cone piece;

[0041] [Fig. 12] represents a cross-sectional view taken along plane P5 of [Fig. 11];

[0042] [Fig. 13] represents a cross-sectional view taken along plane P6 of [Fig. 11];

[0043] [Fig. 14]

[0044] [Fig. 15] are perspective views schematically illustrating a second step in mounting the second cone piece onto the first cone piece;

[0045] [Fig. 16] represents a perspective view cut along plane P7 of [Fig. 15];

[0046] [Fig. 17] represents a perspective view cut along plane P8 of [Fig. 15];

[0047] [Fig. 18] is a schematic cross-sectional view of a third assembly step of the second cone piece on the first cone piece;

[0048] [Fig. 19] is a perspective view schematically illustrating the third step of mounting the second cone piece onto the first cone piece;

[0049] [Fig.20]

[0050] [Fig.21] are perspective views schematically representing the two fixing flanges according to a second preferred embodiment of the invention, respectively represented in a non-assembled position, and in an axial coupling position;

[0051] [Fig.22]

[0052] [Fig.23] are perspective views schematically showing the two fixing flanges according to a third preferred embodiment of the invention, respectively represented in an unassembled position, and in an axial coupling position;

[0053] [Fig.24] is a partial cross-sectional view schematically showing the two fixing flanges according to a fourth preferred embodiment of the invention, in an axial coupling position. DETAILED EXPLANATION OF PREFERRED METHODS OF IMPLEMENTATION

[0054] With reference first to [Fig. 1], an aircraft turbomachine 1, according to the invention, is shown. This is a twin-spool, turbofan engine. However, it could be a turbomachine of another type, for example a turboprop, without departing from the scope of the invention.

[0055] The turbojet 1 has a longitudinal axis 3, around which its various components extend. It comprises, from upstream to downstream along a main direction 5 of gas flow through this turbomachine, a fan 2, a low-pressure compressor 4, a high-pressure compressor 6, a combustion chamber 8, a high-pressure turbine 10 and a low-pressure turbine 12.

[0056] Conventionally, these elements define a primary channel 14a in which a primary flow 16a circulates, and a secondary channel 14b in which a secondary flow 16b circulates. In this dual-flow design, an intermediate housing 20 is provided, arranged downstream of the blower 2. The intermediate housing comprises a hub 22, radial arms 24, and an external ferrule 26 extending downstream from a blower housing.

[0057] Here, the high-pressure turbine 10 and the high-pressure compressor 6 are connected by a high-pressure shaft 30, while the low-pressure turbine 12 and the low-pressure compressor 4 are connected by a low-pressure shaft 32, preferably passing through the high-pressure shaft 30. A rotating blower shaft 34 is also provided, driving the blower blades in rotation around the axis 3, on which the three shafts 30, 32, 34 are centered.

[0058] In the configuration shown, the blower shaft 34 is driven by means of a reducer 36, which is itself driven by the low-pressure shaft 32. However, driving the blower directly by the low-pressure body remains possible, without departing from the scope of the invention.

[0059] At the rear of the turbojet engine, the low-pressure turbine 12 usually comprises one or more stages, each stage including a bladed rotor wheel and a bladed stator wheel, also called a turbine distributor. These wheels are thus arranged axially in alternating directions. At the rear of the last bladed wheel of the last stage of this low-pressure turbine 12, a stator structure is provided, formed by a fixed turbine housing 44, corresponding to a rear housing of turbine, or TRF casing. This turbine casing 44 includes a fixed bladed wheel, which is located axially opposite the last moving turbine wheel.

[0060] A gas ejection cone 50, forming an exhaust structure of the turbojet, is preferably mounted on this rear turbine casing 44. Around an upstream portion of this cone 50, another annular aerodynamic structure 52 is provided, designed to separate the primary flow 14a from the secondary flow 14b in the radial direction. This aerodynamic structure 52 forms part of a nacelle 51 equipping the turbojet, as schematically shown in [Fig. 2].

[0061] Downstream of this other aerodynamic structure 52, the gas ejection cone 50 is no longer radially covered, and its outer surface is intended to be embraced by a mixture of the primary flow 16a and the secondary flow 16b.

[0062] In [Fig. 1], the cone 50 is made by assembling a first part 54 with a second part 56 arranged in axial continuity with the first part, downstream of it. A fastening device 58 enables such an assembly between the two parts 54, 56, and its design specific to the present invention will be detailed below.

[0063] The axial extent of the first part 54 is identical or substantially identical to the axial extent of the aerodynamic structure 52 surrounding it. Annular in shape, centered on axis 3, the first part 54 may be cylindrical, or flare slightly downstream. The second part 56, on the other hand, is conical or frustoconical in shape, also centered on axis 3, with a cross-section that narrows downstream. In this respect, it is noted that each of the two parts 54, 56 extends centered around axis 3, preferably in a closed 360° configuration. However, this angular extent may be less than 360° for one or both parts, for example, to allow the passage of other elements, such as the mast, and thus present a non-closed, or open, configuration.Furthermore, regardless of the angular extent of each of these two parts 54, 56, they can each be made in one piece, or obtained by assembling several angular sectors of a part placed end-to-end. Moreover, if the preferred solution provides that the axis 3 on which parts 54, 56 are centered corresponds to the longitudinal axis of the turbojet engine, these parts could nevertheless be centered on an axis other than this longitudinal axis of the turbojet engine, for example, an axis intersecting this longitudinal axis of the turbojet engine. Furthermore, while both remaining arranged around the same axis, the two parts 54, 56 could be centered respectively on two distinct axes, preferably two intersecting axes, one of which would preferably be the longitudinal axis of the turbojet engine.

[0064] The cone 50 is also fixed to the housing 44 by means of a fastening device 58, via the upstream end of the first part 54. The fastening device 58, which secures the assembly between the two parts, will be described subsequently. 54, 56, but it is understood that this design can also be adopted for the fastening device ensuring the connection between the cone 50 and the rear turbine housing 44, the latter then forming the first part within the meaning of the present invention. When this latter embodiment is implemented, the cone 50 may have a two-piece design such as that shown above, or be made of a single piece.

[0065] In the case described below, with the cone 50 formed by assembling the first and second parts 54, 56, which respectively constitute a first and second part of the cone 50, its mounting on the housing 44 can be achieved by means of a conventional connection with an annular row of bolts. To perform maintenance operations inside the turbojet engine, access can be provided by simply removing the second part of the cone 56, via the quick disassembly of the fastening device 58 between the two parts 54, 56.

[0066] With reference now to figures 3 to 18, a first preferred embodiment of the invention will be described, in which the fastening device 58 comprises a first fastening flange 64 belonging to the first part 54, and a second fastening flange 66 cooperating with the first fastening flange 64, and belonging to the second part 56. The two fastening flanges 64, 66 are annular, centered on the axis 3.

[0067] With reference first to figures 3 to 8, the two fixing flanges 64, 66 of the fixing device 58 will be described, in an unassembled position of the two parts 54, 56, forming an assembly 55 specific to the invention.

[0068] The first flange 64 comprises, alternately along a circumferential direction of the assembly relative to the axis 3, first axial openings 68 and first axial stop members 70 projecting radially inwards. Similarly, the second flange 66 comprises, alternately along this same circumferential direction, second axial openings 78 and second axial stop members 80 projecting radially outwards. The angular range of each of these elements 68, 70, 78, 80 is preferably identical or similar, for example, on the order of 15 to 30°.

[0069] The first mounting flange 64 has, associated with each first axial opening 68, an opening bottom 72, which obstructs its corresponding opening 68 axially upstream. As will be detailed below, the opening bottom 72, projecting radially inwards, constitutes an axial stop for one of the second axial stop members 80, when the first and second parts 54, 56 are brought into their uncoupled axial position. It is noted that each opening bottom 72 is therefore circumferentially located between two first axial stop members 70, being arranged upstream of these two members 70, with an offset axial substantially equal to the axial thickness of the second axial stop members 80. Each opening bottom 72 can be in the form of a tongue extending circumferentially, over all or part of the angular extent of the first axial opening 68 which it obstructs upstream.

[0070] In addition, each second axial stop member 80 also takes the form of a circumferential tongue projecting radially outwards from an upstream axial end of a base 74 of the second fixing flange 66. The base 74 and each stop member 80 thus form a hook, intended to cooperate with a first stop member 70.

[0071] At one of its circumferential ends, each stop member 80 defines a circumferential opening 76 with the base 74, as can be seen in [Fig. 4]. At the opposite circumferential end, the second stop member 80 is connected to an axial edge 82, which runs axially along the base 74, downstream. The radial height of the second stop member 80 is preferably identical or substantially identical to the radial height of this axial edge 82. The distinctive feature of this edge is that it forms part of a circumferential stop mechanism, configured to prevent the relative rotation between the first and second parts 54, 56, when these parts are brought into their axial coupling position, as will be described later.

[0072] With reference now more specifically to figures 9 to 13, a first step of a method of assembling the assembly 55 is shown, consisting of bringing the first and second cone pieces 54, 56 from the unassembled position shown in [Fig.3], to a position of engagement between these pieces, but not yet axially coupled to each other.

[0073] To do this, the two cone pieces 54, 56 are arranged coaxially, at a distance from each other, and then brought together axially so as to insert the first stop members 70 into the second axial openings 78, and so as to insert the second stop members 80 into the first axial openings 68. The relative axial displacement is stopped by the contact of the second stop members 80 with the corresponding opening bottoms 72, as is best seen in [Fig. 12].

[0074] This first step can be carried out manually by a single operator. Once the two parts 54, 56 are in their engagement position, but not axially coupled to each other, they are temporarily held relative to each other by means of the radial guidance provided by the cooperation between the elements 68, 70, 78, 80.

[0075] A second step of the process consists in moving the first and second parts 54, 56 from their position not axially coupled to each other, to an axially coupled position, by rotating the two parts relative to each other, according The longitudinal axis 3. This second step is illustrated schematically in Figures 14 to 17. The initiation of this relative rotation causes each second axial stop 80 to position itself upstream of the first axial stop 70, which is directly adjacent to it in the direction of rotation. In other words, this first stop 70 penetrates circumferentially into the circumferential opening 76 described with reference to [Fig. 4], and this leads to the axial cooperation of the stop 70 and 80 in pairs. The rotation is stopped when the axial edge 82, also described with reference to [Fig. 4], comes into circumferential contact with one end of the first stop 70, thus forming a complementary part of the aforementioned circumferential stop means.

[0076] At this stage, the two parts 54, 56 are axially coupled in such a way as to allow the mechanical forces to be transferred in the axial direction, in the radial direction, and also in a first direction of the circumferential direction. This results in particular from the hooks formed by the first axial stop members 80, which radially curve inwards around the first axial stop members 70, the latter fitting with a small radial clearance inside these same hooks.

[0077] In order to lock the fastening device 58 in the axial coupling position of the two parts 54, 56, and thus prevent their relative movement in the second direction of the circumferential direction, the method includes a third locking step in position, shown schematically in figures 18 and 19. For this purpose, locking members 84 are mounted on the parts 54, 56, these members 84 preferably taking the form of screws. Indeed, each screw 84 is mounted radially from the outside of the assembly 55, so as to pass through the two flanges 64, 66. More precisely, each locking screw 84 passes through a through hole of one of the first axial stop members 70, as well as a through hole located in continuity with the previous one, and passing through the base 74 of the second fixing flange 66. This may include a nut 86, for example mounted floating on the base 74, into which the screw 84 is screwed.Alternatively, it may be a set screw, not requiring a nut to achieve the desired effect, namely locking the second part 56 against rotation relative to the first part 54, along the longitudinal axis 3.

[0078] The mounting of these screws 84 can thus be carried out blindly from outside the gas ejection cone. Furthermore, since the circumferential forces to be resisted by these screws 84 remain low, their number can be significantly reduced compared to conventional solutions with two simply bolted flanges. For example, this number can be reduced to between three and six, for instance, four screws 84 arranged at 90° to each other. In order to limit losses aerodynamic on the outer surface of the cone, the head of each of these locking screws is housed in a counterbore 88 of the first flange 64.

[0079] In this first preferred embodiment, each locking screw 84 preferably has a radial, or substantially radial, orientation, although other orientations remain conceivable, preferably always with a non-zero radial component.

[0080] Figures 20 to 23 show other preferred embodiments of the invention, similar to the first embodiment described above, in that the two flanges 64, 66 are intended to cooperate with each other after a relative movement between them, corresponding to a combination of a translation along the axis 3, followed by a rotation around this same axis.

[0081] Indeed, in a second preferred embodiment shown in Figures 20 and 21, the second mounting flange 66 comprises pins 90 spaced circumferentially from one another. Each pin 90 preferably extends upstream along the axial direction, i.e., parallel to the axis 3, having a widened distal end, this distal end 91 corresponding to the upstream end of the pin. Furthermore, the first mounting flange 64 comprises slots 92 spaced circumferentially from one another. Each slot 92 passes axially through the first flange 64 and extends circumferentially, having a widened circumferential end 93.

[0082] Thus, for the assembly of the two flanges 64, 66, the translation between the two parts 54, 56 allows the enlarged pin heads 91 to penetrate through the enlarged circumferential ends 93 of the slots 92. Then, the relative rotation of the two parts 54, 56 allows the pins 90 to be axially locked in these slots 92, as shown schematically in [Fig. 21]. The resulting axial coupling arises from the fact that the enlarged diameter of the distal ends 91 of the pins 90 is greater than the width of the slots 92 through which these pins pass.

[0083] For locking the two parts 54, 56 in the axial coupling position, locking members (not shown) cooperate with the two flanges 64, 66. They are of the type of those shown in the first preferred embodiment, or of similar design.

[0084] According to a third preferred embodiment of the invention shown in Figures 22 and 23, the fastening device 58 is of the bayonet type. Indeed, the second flange 66 is also equipped with pins 94 spaced circumferentially from each other, and oriented in a direction with a non-zero radial component, for example orthogonally or substantially orthogonally locally to the aerodynamic outer surface of the gas ejection cone.

[0085] The first mounting flange 64 has circumferentially spaced notches 96. Each notch 96 has a portion axial 98, open axially downstream at one of its two opposite axial ends. At the other of these two ends, namely the upstream end, each notch 96 has a circumferential portion 100, initiated from this other end of the axial portion 98. Each notch 96 therefore presents a path in the general shape of an L, typical of bayonet assemblies and intended to be followed by a corresponding pin 94, during assembly.

[0086] Thus, for the assembly of the two flanges 64, 66, the translation between the two parts 54, 56 allows the radial pins 94 to penetrate the axial portions 98 of the notches. Then, the relative rotation of the two parts 54, 56 allows the pins 94 to be axially locked in the circumferential portions 100 of these notches, as shown schematically in [Fig. 23].

[0087] For locking the two parts 54, 56 in the axial coupling position, locking members 84 cooperate with the two flanges 64, 66. They are of the type of those shown in the first preferred embodiment, or of similar design.

[0088] Finally, [Fig. 24] represents a fourth preferred embodiment of the invention, in which the first and second flanges 64, 66 define a helical connection by means of threads 102, 104 respectively provided on these flanges. The threads are centered on the axis 3, and they effectively allow the two parts 54, 56 to be axially coupled, by simple relative rotation between them, around the axis 3. The thread 102 provided on the first flange 64, the upstream one, is oriented radially inwards, while the thread 104 provided on the second flange 66 is oriented radially outwards.

[0089] Here too, locking devices (not shown) may be provided, of identical or similar design to the locking devices described above.

[0090] Of course, various modifications can be made by a person skilled in the art to the invention just described, solely by way of non-limiting examples, and the scope of which is defined by the appended claims. Furthermore, all the features disclosed above, in the various preferred embodiments and their alternatives, are combinable with one another. Moreover, it is noted that in all the figures described above, elements bearing the same numerical references correspond to identical or similar elements.

Claims

Demands

1. Assembly (55) for aircraft turbomachine, comprising a first turbomachine part (54) and a second turbomachine part (56) located downstream of the first part, the first and second parts (54, 56) extending around a longitudinal axis (3), the second part (56) corresponding to all or part of a gas ejection cone (50) for turbomachine, the assembly comprising a fastening device (58) for the first part on the second part, characterized in that the fastening device (58) is configured so as to allow the first and second turbomachine parts (54, 56) to move from a position not axially coupled to each other, to a position of axial coupling, by rotation of one relative to the other about the longitudinal axis (3).

2. Assembly according to claim 1, characterized in that it comprises at least one locking member (84) of the first and second turbomachine parts (54, 56) in their axial coupling position, each locking member (84) being arranged so as to lock the second part (56) in rotation, relative to the first part (54), along the longitudinal axis (3), each locking member preferably being a screw.

3. 3. Assembly according to any one of the preceding claims, characterized in that the second turbomachine part (56) is a second part of the gas ejection cone, and in that the first turbomachine part (54) is a first part of the gas ejection cone (50), arranged upstream of the second part.

4. 4. Assembly according to any one of claims 1 and 2, characterized in that the second turbomachine part (56) forms the entirety of the gas ejection cone, and in that the first turbomachine part is a housing (44) of the turbomachine, preferably a rear turbine housing.

5. 5. Assembly according to any one of the preceding claims, characterized in that the fastening device (58) comprises a first fastening flange (64) belonging to the first part (54), and a second fastening flange (66) cooperating with the first fastening flange, and belonging to the second part (56).

6. Assembly according to claim 5, characterized in that the first flange (64) comprises, alternately along a circumferential direction of the assembly, first axial openings (68) and first axial stop members (70) projecting radially, the second flange (66) comprises, alternately along the circumferential direction of the assembly, second axial openings (78) and second axial stop members (80) projecting radially, the fastening device (58) being configured so as to first bring the first and second parts into their uncoupled axial position by inserting the first stop members (70) into the second axial openings (78) and the second stop members (80) into the first axial openings (68), and then to bring the first and second parts into their axially coupled position by rotating one relative to the other about the longitudinal axis. (3),leading the first and second axial thrust bearings (70, 80) to cooperate with each other.

7. Assembly according to claim 5, characterized in that one of the first and second fixing flanges (64, 66) comprises pins (94) spaced circumferentially apart from each other, each pin extending preferably in a direction with a non-zero radial component, and in that the other of the first and second fixing flanges (64, 66) comprises notches (96) spaced circumferentially apart from each other, each notch comprising an axial portion (98) open axially at one of its two opposite ends, as well as a circumferential portion (100) initiated from the other of the two opposite ends of the axial portion (98).

8. Assembly according to claim 5, characterized in that one of the first and second fixing flanges (64, 66) comprises pins (90) spaced circumferentially apart from each other, each pin preferably extending axially and comprising an enlarged distal end (91), and in that the other of the first and second fixing flanges (64, 66) comprises slots (92) spaced circumferentially apart from each other, each slot comprising an enlarged circumferential end (93).

9. Assembly according to claim 5, characterized in that the first and second fixing flanges (64, 66) form a helical link (102, 104), centered on the longitudinal axis (3).

10. 15 10. Method of mounting an assembly (55) for an aircraft turbomachine according to any one of the preceding claims, comprising a step of moving the first and second parts (54, 56) from their position not axially coupled to each other, to their axially coupled position, by rotating one relative to the other about the longitudinal axis (3).