EXHAUST COVERING WITH A HOLLOW ARM THROUGH WHICH A POWER TRANSMISSION CONDUCTOR ELEMENT PASSES

Abstract

The invention relates to an exhaust casing (24) for an aircraft turbomachine, said casing (24) having a main axis (A) and comprising an internal annular ferrule (44) and an external annular ferrule (46) extending around said axis (A) and joined by at least one hollow arm (48) extending radially with respect to said axis (A) and opening into said ferrules (46, 48), characterized in that it further comprises at least one power transmission conductive element (50) which has a generally elongated and curved shape and which passes through said hollow arm (48), this conductive element (50) comprising at least one rigid section (54) and comprising a first connection end (56) located radially outside the external ferrule (46), and a second connection end (58) located radially inside the internal ferrule (44) and oriented substantially parallel to said main axis (A). Figure for the abbreviation: Figure 2.

Description

Title of the invention: EXHAUST CASING COMPRISING A HOLLOW ARM CROSSED BY A POWER TRANSMISSION CONDUCTIVE ELEMENT Technical field of the invention

[0001] The invention relates to a turbomachine exhaust casing allowing the conveyance of electrical power between two electrical components located respectively outside and inside the casing, via a conductive power transmission element passing through this casing.

[0002] The invention relates to a hybrid turbomachine exhaust casing intended to allow electrical connection to an electrical machine located downstream of this casing, coaxially and internally to it. Technical background

[0003] The state of the art includes in particular documents FR-A1-2.842.565, FR-Al-2.896.537, FR-A1-2.9220265, FR-3.087.823, FR-3.103.851, FR-2.922.265, FR-2.842.565 and FR.2.896.537 which describe turbomachines equipped with electric machines.

[0004] The aeronautical world is currently asking itself many questions about the relevance of using hybrid engines for commercial aviation. The use of electrical energy is currently being considered not only to meet aircraft functions but also to electrify turbomachine functions.

[0005] This observation leads to the study of hybrid engine architecture solutions, i.e. to the development of hybrid turbomachines combining fossil fuel energy and electrical energy to ensure the drive of the propulsion part (turbomachine fan) and the power supply of certain functions of the engines and / or the aircraft.

[0006] These architectures may in particular be based on two- or multiple-body architectures, in which the turbomachine comprises one or more low-pressure bodies and one high-pressure body, each body comprising a shaft connecting a rotor of a compressor to a rotor of a turbine.

[0007] Among these architectures, we find in particular the architectures of the high dilution ratio and reducer type (UHBR ID, anglo-Saxon acronym for Ultra High By Pass Ratio, Integral Drive), which concern dual-flow engine configurations comprising a high-pressure body and a low-pressure body which itself drives a very high bypass ratio ducted fan via a reducer coupled to a transmission line of the low pressure body, in order to be able to independently optimize the rotation speeds of the fan and the low pressure body.

[0008] In any event, such turbomachines may comprise one or more electrical machines mechanically coupled to the low pressure or high pressure bodies of the turbomachine, with powers ranging from a few kW to several MW.

[0009] This multiplication of electrical machines induces an increase in the complexity of the wiring to be carried out, especially since the modular design of the turbomachines in the form of axial modules implies that the electrified modules can be delivered with their connectors, ready to be assembled with the other modules of the turbomachine.

[0010] Furthermore, the integration of a high-power electrical machine on the low-pressure part of the turbomachine, in particular in the case of a UHBR ID type architecture for which the reducer already occupies a large volume, generally at the level of the low-pressure compressor, proves to be very complex. Several installation zones are possible, upstream or downstream of the low-pressure body, with advantages and disadvantages for each in terms of mechanical integration, environmental temperature, cooling, routing of services and accessibility.

[0011] However, one of the most favorable areas for the integration of an electric machine in terms of size is located downstream of the exhaust casing, also designated by the initials TRF, an Anglo-Saxon acronym for Turbine Rear Frame, coaxially and inside it.

[0012] However, it is important to electrically connect the electrical machine to the aircraft and for this at least one power transmission element must cross the gas stream to be connected in the zone inside the stream and in the zone outside the stream.

[0013] There is therefore a real need for a path of at least one power transmission element through the gas stream of the turbomachine. Summary of the invention

[0014] The present invention meets this need by proposing a path for the power transmission element through an arm of the exhaust casing.

[0015] For this purpose, the invention proposes an exhaust casing for an aircraft turbomachine, said casing having a main axis and comprising an internal annular shell and an external annular shell extending around said axis and joined by at least one hollow arm extending radially relative to said axis and opening into said ferrules, characterized in that it further comprises at least one conductive power transmission element which has a generally elongated and curved shape and which passes through said hollow arm, this conductive element comprising at least one rigid section and comprising a first connection end located radially outside the outer ferrule, and a second connection end located radially inside the inner ferrule and oriented substantially parallel to said main axis.

[0016] This configuration advantageously makes it possible to use a pre-existing hollow arm to ensure the passage of the power transmission conductive element. In the context of an assembly of a turbomachine by modules, it makes it possible to propose a pre-equipped modular exhaust casing, already provided with the power transmission conductive element.

[0017] According to another characteristic of the exhaust casing, the rigid section can extend at least radially from the first end into the arm.

[0018] This feature is particularly advantageous because it allows the use of a rigid section, also known as a power bar, to form the curved part of the power transmission conductive element. Indeed, large diameter flexible harnesses have very large bending radii, which is not always compatible with such a route. In addition, the integration of harnesses requires supports to avoid vibrations that could damage the surrounding parts. The use of a rigid section in the arm instead of a harness overcomes this problem.

[0019] According to other characteristics of the exhaust casing:

[0020] - the rigid section of the power transmission conductive element extends between the first and second ends,

[0021] - the power transmission conductive element is bent at 90 degrees,

[0022] - the conductive element passes through a plate at its first end fixing on the external ferrule,

[0023] - the plate closes an opening in the external ferrule into which the arm opens hollow, said opening being crossed by said conductive element,

[0024] - said first end is bent in an L shape and comprises a part which extends sen possibly tangentially to the outside of the outer shell,

[0025] - the conductive element comprises a section of electrical harness which extends between the rigid section and up to the second end,

[0026] - each of the first and second ends is shaped in the form of a tab comprising a mounting hole for a screw-type fixing element,

[0027] The invention also relates to an aircraft turbomachine comprising an exhaust casing of the type described above, in which the exhaust casing is mounted downstream of at least one turbine of the turbomachine, and in which the second end of the conductive element is fixed to a power bar which is fixed to an electrical machine mounted downstream of the exhaust casing along the main axis and inside a nozzle.

[0028] The invention also relates to an exhaust casing of the type described above, characterized in that it comprises at least successively:

[0029] - a step during which the second connection end of the curved power transmission conductive element in front of the hollow arm opening into the external shell,

[0030] - a step during which the conductive element is introduced into the hollow arm by simultaneously giving it a tilting movement around a transverse axis along a curved trajectory until the second end emerges from the hollow arm inside the internal shell, parallel to the main axis of the exhaust casing,

[0031] - a step during which the conductive transmission element is fixed power to the outer shell of the exhaust casing.

[0032] More particularly, the assembly method comprises:

[0033] - a first step during which the rigid section of bar is introduced power through the plate and it is fixed to said plate,

[0034] - a second step during which the second end of connection of the curved conductive element in front of the arm opening into the external ferrule,

[0035] - a third step during which the conductive element is introduced into the hollow arm by simultaneously giving it a tilting movement around a transverse axis along a curved trajectory until the second end comes out of the arm inside the internal shell, parallel to the main axis of the exhaust casing,

[0036] - a fourth step during which the plate is fixed to the outer ferrule of the exhaust casing.

[0037] This process therefore makes it possible to obtain a pre-equipped modular exhaust casing, ready for assembly with other elements of the turbomachine.

[0038] As a result, it is then possible to envisage a method of assembling a hybrid turbomachine which comprises at least successively:

[0039] - a first step of supplying a modular exhaust casing and a electric machine equipped with a power bar,

[0040] - a second step during which the electric machine is aligned with the modular exhaust housing,

[0041] - a third step during which the electric machine is fixed to the casing modular exhaust,

[0042] - a fourth step during which the conductive element of power transmission of the casing and the power bar of the machine by their connection tabs using a transverse bolt and two half-housings previously threaded respectively onto the conductive element of the modular casing and onto the power bar of the electric machine are slid to form a housing encapsulating said transverse bolt, said tabs, a part of the conductive power transmission element of the modular casing and a part of the power bar of the electric machine. Brief description of the figures

[0043] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0044] [Fig-1] [Fig.l] is a schematic view of a hybrid turbomachine comprising an exhaust casing according to the invention;

[0045] [Fig.2] [Fig.2] is a detailed sectional view of the rear end of the hybrid turbomachine of [Fig.l];

[0046] [Fig.3] [Fig.3] is a detailed perspective view of the rear end of the hybrid turbomachine of [Fig.l] comprising an exhaust casing according to a first embodiment of the invention;

[0047] [Fig.4] [Fig.4] is a detailed perspective view of a power transmission conductive element for the exhaust casing according to the first embodiment of the invention;

[0048] [Fig.5] [Fig.5] is a detailed perspective view of the rear end of the hybrid turbomachine of [Fig.l] comprising an exhaust casing according to a second embodiment of the invention;

[0049] [Fig.6] [Fig.6] is a detailed perspective view of a power transmission conductive element for the exhaust casing according to the second embodiment of the invention;

[0050] [Fig.7] [Fig.7] is a detailed perspective view of the connection between the legs of a power transmission conductive element and a power bar of an electrical machine;

[0051] [Fig.8] [Fig.8] is a detailed perspective view of the connection between the legs of a power transmission conductive element and an electric machine power bar, protected by a housing;

[0052] [Fig.9] [Fig.9] is a sectional view illustrating a first step of assembling an exhaust casing according to the invention;

[0053] [Fig. 10] [Fig. 10] is a sectional view illustrating a second step of assembling an exhaust casing according to the invention;

[0054] [Fig. 11] [Fig. 11] is a sectional view illustrating a third step of assembling an exhaust casing according to the invention;

[0055] [Fig. 12] [Fig. 12] is a sectional view illustrating the assembly of a hybrid turbomachine according to the invention;

[0056] [Fig. 13] [Fig. 13] is a perspective view of a power bar for an electric machine of a hybrid turbomachine according to the invention;

[0057] [Fig. 14] [Fig. 14] is a block diagram illustrating the steps of assembling an exhaust casing according to the invention;

[0058] [Fig. 15] [Fig. 15] is a block diagram illustrating the assembly steps of a hybrid turbomachine according to the invention. Detailed description of the invention

[0059] [Fig.l] shows a hybrid aircraft turbomachine 10 according to the invention.

[0060] Like the turbomachines known from the state of the art, the turbomachine 10 is a dual-flow turbomachine which comprises, from upstream to downstream, a fan 12, a low-pressure compressor 14 also called a booster, a high-pressure compressor 16, a combustion chamber 18, a high-pressure turbine 20, and a low-pressure turbine 22. Downstream of the low-pressure turbine 22 is arranged an exhaust casing 24 (or “TRF” according to the aeronautical term, TRF being the acronym for the well-known Anglo-Saxon term “Turbine Rear Frame”), which is positioned at the downstream end of the turbomachine 10. At the downstream end of this exhaust casing and coaxially thereto is fixed a nozzle cone, which is an aerodynamic element also called a plug 26, and which makes it possible to guide the exhaust gases at the outlet of the turbomachine 10.

[0061] The low pressure compressor 14, high pressure compressor 16, combustion chamber 18, high pressure turbine 20, and low pressure turbine 22 delimit a gas stream 23 which is crossed by a primary flow P. Around these elements, the turbomachine 10 is also crossed by a secondary flow S which is driven by the fan 12. The primary flows P and secondary flows S meet at the outlet of the turbomachine 10.

[0062] The high-pressure compressor 16 and the high-pressure turbine are connected by a high-pressure shaft 28 and form a high-pressure body. The low-pressure compressor 14 and the low-pressure turbine 22 are connected by a low-pressure shaft 30 and form a low-pressure body. The low-pressure shaft 22 drives the fan 12 via a reducer 34 which is arranged substantially in a front casing 36 of the turbomachine, also called the inlet casing, in line with fixed guide vanes in outlet 38 which are also called OGV (Anglo-Saxon acronym for Outlet Guide Vanes), and which straighten the secondary flow S downstream of blower 12.

[0063] The turbomachine 10 comprises several casings, namely, as already seen, the front casing 36 or inlet casing which supports the fixed outlet guide vanes 38 and the exhaust casing 24. It also comprises an intermediate casing 40 arranged axially between the low pressure compressor 14 and the combustion chamber 16, and a turbine casing 42 arranged axially between the high pressure turbine 20 and the low pressure turbine 22.

[0064] Such a turbomachine configuration is known by the acronym (UHBR ID, an English acronym for Ultra High By Pass Ratio, Integral Drive), which relates to dual-flow engine configurations comprising a high-pressure body and a low-pressure body which drives a ducted fan with a very high bypass ratio.

[0065] The turbomachine 10 according to the invention is a hybrid turbomachine, that is to say that it comprises an electric machine 42 which is coupled to the low pressure shaft 30. The hybrid turbomachine architecture 10 according to the invention more particularly comprises an electric machine 42 which is arranged downstream of the low pressure turbine 22 and the exhaust casing 24, coaxially therewith along the main axis A, and which is housed in the plug 26 inside a nozzle of the turbomachine.

[0066] For its electrical power supply, it is necessary that at least one conductive power transmission element passes through the vein 23, this in order to ensure the electrical connection of the electrical machine 42 with at least one member external to the vein 23, and in particular with the turbomachine.

[0067] The invention makes it possible to ensure the routing of this power transmission conductive element by advantageously using the exhaust casing 24.

[0068] In a known manner, as illustrated in [Fig. 2], the exhaust casing 24 has a main axis A and it comprises an internal annular ferrule 44 and an external annular ferrule 46 extending around said axis A which are joined by at least one hollow arm 48 extending radially relative to the axis A and opening into said ferrules 44, 46.

[0069] The hollow arm 48 is preferably tubular in shape, with an elliptical or oblong section, with an aerodynamic external profile.

[0070] This configuration is conventional since generally the exhaust casing 24 is a molded part and the arm 48 is hollow and opens into the ferrules 44, 46 to allow the evacuation of the molding cores.

[0071] According to the invention, the casing 24 further comprises at least one power transmission conductive element 50 which has a generally elongated shape and curved and which passes through the hollow arm 48. The power transmission conductive element 50 is curved at an angle of substantially 90° to allow the change in the orientation of the conductive element 50 between the radial direction of the arm 48 and a direction substantially parallel to the main direction A of the exhaust casing 24 and the electric machine 42, this in order to allow the connection of the conductive element 50 with a power bar 52 of the electric machine 42.

[0072] According to the invention, the conductive element 50 comprises at least one rigid section 54 which comprises a first connection end 56 located radially outside the outer ferrule 46, and a second connection end 58 located radially inside the inner ferrule 44. This second connection end 58 extends axially beyond the trailing edge of the arm 48 of the exhaust casing 24 and is, as previously mentioned, oriented substantially parallel to the main axis A to allow connection to the power bar 52 of the electrical machine 42.

[0073] The rigid section 54 extends at least radially from the first end 56 into the arm 48 of the casing 24.

[0074] This configuration is particularly advantageous, because the conformation of the conductive element 50 in the form of a rigid section 54 similar to a power bar inside the arm 48 makes it possible to give it a bending that would not necessarily be possible to give to a flexible harness. Furthermore, the rigidity of the section 54 of the conductive element 50 makes it possible to dispense with any holding means in the arm 48 that would be necessary if the conductive element 50 were shaped in the form of a harness. This is particularly advantageous with regard to the part of the conductive element 50 located inside the internal annular ferrule 44, because as a result the position of the second connection end 58 can adapt to the position of the electrical machine 42 and the connector of the power bar 52.

[0075] Two embodiments of the conductive element 50 can then be envisaged.

[0076] According to a first embodiment of the conductive element 50 which has been shown in FIGS. 3 and 4, the rigid section 54 of the power transmission conductive element 50 extends between the first and second ends 56, 58. In this case, the rigid section 54 of the power transmission conductive element 50 extends along the entire length of said element 50, the power transmission conductive element 50 then being shaped in the form of a curved power bar, which is covered with an insulator 60.

[0077] According to a second embodiment of the conductive element 50 which has been shown in FIGS. 5 and 6, the conductive element 50 comprises a section of electrical harness 62, also called “power feeder”, which extends between the rigid section 54 and up to the second end 58. In this case, the rigid section 54 of the power transmission conductive element 50 only extends in the arm 48, and the electrical harness section 62 extends this rigid section 54 up to the second end 58. The entire conductive element 50 is also covered with the insulation 60.

[0078] As will be understood, in these two embodiments, the rigid section 54 of the power transmission conductive element 50 makes it possible to dispense with the need to fix a harness inside the arm 48.

[0079] To ensure the attachment of the power transmission conductive element 50 to the casing 24, advantage is taken of the rigidity of the section 54 by attaching it to the part of the casing 24 through which it extends in each of the two embodiments of the invention. Thus, as can be seen in FIGS. 3 to 6, the conductive element 50 passes through, at its first end 56, a plate 64 for attachment to the external ferrule 46.

[0080] The plate 64 closes an orifice 66 of the hollow arm 48 which opens into the external ferrule 46 and which is crossed by the conductive element 50. It is fixed to the external ferrule 46 by means of screws 68.

[0081] Above the plate 64, that is to say outside the external ferrule 46, as can be seen in FIGS. 3 and 5, the first end 56 of the conductive element 50 is bent in an L shape and it comprises a part 70 which extends substantially tangentially to the outside of the external ferrule 46. This configuration makes it possible to ensure the connection of the conductive element 50 with an electrical harness 72 of the aircraft without the first end 56 protruding excessively and risking interfering with the environment of the casing 24.

[0082] Whether it is the first end 56 or the second end 58, each of its ends is shaped in the form of a tab comprising an orifice 74 for mounting a screw-type fixing element 76. This type of mounting is commonly called a lug system fixing.

[0083] This configuration has been shown more particularly in [Fig.7] which represents the connection of the second end 58 of the conductive element 50 to one end 80 of the power bar 52 of the electrical machine 42.

[0084] The end 80 of the power bar 52 is also crossed by a mounting hole 78, and the two mounting holes 74, 78 are crossed by the screw-type fixing element 76 which is here a bolt consisting of a screw 76a, a nut 76b, and support washers 76c.

[0085] To protect the connection of the ends 58, 80, a housing 82 is used, for example, encapsulating the bolt 76, the tabs of the ends 58, 80 and a part of the conductive element 50 and the power bar 52. This housing 82 is preferably composed of two half-housings 82a, 82b, male and female, joined together and mounted respectively on the conductive element 50 and the power bar 52 and which together delimit a receiving cavity 32 of the bolt 76. The two half-housings 82a, 82b, once assembled together, guarantee the protection and sealing of the connection.

[0086] As illustrated in [Fig. 13], it may occur, in particular in the case of the use of a conductive element 50 shaped in the form of a rigid power bar, that the orientation of the lug of the end 58 of the conductive element 50 and of the end 80 of the power bar 52 is in a different plane from a terminal lug of the power bar 52 of the electrical machine. In this case, it is possible to envisage a power bar 52 having a twisted shape, allowing the power bar 52 to have end lugs arranged in different planes. As can be seen, the terminal lug 84 of the power bar 52 is arranged in a plane substantially perpendicular to that of the lug of the end 80 of this same power bar 52.

[0087] Generally speaking, as illustrated in Figures 9, 10, 11 and 14, the exhaust casing 24 can be assembled in a very simple manner according to a method comprising at least a first step ET1 during which the first end 56 of the rigid section 54 of the power bar 50 is introduced through the plate 64, and it is fixed to this plate 64.

[0088] Then, during a second step ET2 shown in [Fig.9], the second connection end 58 of the curved power transmission conductive element is presented in front of the arm 48 opening into the external ferrule 46, that is to say in front of the opening 66 of the external ferrule 46.

[0089] Then, during a third step ET3 shown in [Fig. 10], the conductive element 50 is introduced into the hollow arm 48 while simultaneously giving it a tilting movement around a transverse axis along a curved trajectory until the second end 58 emerges from the hollow arm 48 inside the internal shell 44, parallel to the main axis A of the exhaust casing 24.

[0090] Finally, during a fourth step ET4 shown in [Fig.l 1], the power transmission conductive element 50 is fixed to the outer shell 46 of the exhaust casing 24 by means of the plate 64 and the screws 68.

[0091] This method makes it possible to have an exhaust casing 24 pre-equipped with the power transmission conductive element 50, thus forming a modular exhaust casing 24 which can be assembled as part of a modular assembly of the turbomachine. This configuration has been shown in [Fig. 12], where the electrical machine 42 can be seen arranged opposite the exhaust casing 24 pre-equipped with the power transmission conductive element 50. All that then remains is to fix the electrical machine 50 to the exhaust casing 24 and to the low pressure shaft 30.

[0092] In this configuration it will be understood that a hybrid turbomachine 10 according to the invention can be assembled according to a method comprising, as illustrated in [Fig. 15], a first step ET' 1 of providing a modular exhaust casing 24 and an electric machine 42, then a second step ET' 2 during which the electric machine 42 is aligned with the modular exhaust casing 24, as shown in [Fig. 12].

[0093] Then, during a third step ET'3, the electric machine 42 is fixed to the modular exhaust casing 24. Finally, during a fourth step ET'4 (not shown), the conductive element 50 of the casing 24 and the power bar 52 of the machine 42 are connected by their connection tabs using the transverse bolt 76 previously described and the two half-housings 82a, 82b previously threaded respectively onto the conductive element 50 of the modular casing 24 and onto the power bar 52 of the electric machine 42 are slid to form the casing 82 encapsulating the bolt 76, the tabs, the part of the conductive element 50 of the modular casing and the part of the power bar 52 of the electric machine 42 protected by the casing 82.

[0094] The invention makes it possible to reliably and efficiently ensure the delivery of power to an electric machine 42 of a hybrid turbomachine 10.

Claims

Claims

1. Exhaust casing (24) for an aircraft turbomachine, said casing (24) having a main axis (A) and comprising an inner annular shell (44) and an outer annular shell (46) extending around said axis (A) and joined by at least one hollow arm (48) extending radially relative to said axis (A) and opening into said shells (44, 46), characterized in that it further comprises at least one power transmission conductive element (50) which has a generally elongated and curved shape and which passes through said hollow arm (48), this conductive element (50) comprising at least one rigid section (54) and comprising a first connection end (56) located radially outside the outer shell (46), and a second connection end (58) located radially inside the inner shell (44) and oriented substantially parallel to said main axis (A).

2. Exhaust casing (24) according to claim 1, characterized in that the rigid section extends at least radially from the first end (56) into the arm (48).

3. Exhaust casing (24) according to one of claims 1 or 2, characterized in that the rigid section of the power transmission conductive element (50) extends between the first and second ends (56, 58).

4. Exhaust housing (24) according to claim 2, characterized in that the conductive element (50) comprises an electrical harness section (62) which extends between the rigid section (54) and to the second end (58).

5. Exhaust housing (24) according to one of the preceding claims, characterized in that the power transmission conductive element (50) is bent at 90 degrees.

6. Exhaust casing (24) according to one of the preceding claims, characterized in that the conductive element (50) passes through at its first end a fixing plate (64) on the external ferrule (46).

7. Exhaust casing (24) according to the preceding claim, characterized in that the plate (64) closes an opening (66) of the external ferrule (46) into which the hollow arm (48) opens, said opening (46) being crossed by said conductive element (50).

8. Exhaust casing (24) according to one of the preceding claims, characterized in that said first end (56) is bent in an L shape and comprises a portion (70) which extends substantially tangentially to the outside of the external shell (46).

9. Exhaust casing (24) according to one of the preceding claims, characterized in that each of the first and second ends (56, 58) is shaped in the form of a tab (74) comprising an orifice for mounting a fixing element (76) of the screw type.

10. Aircraft turbomachine (10) comprising an electric machine, a nozzle, and an exhaust casing according to one of the preceding claims, in which the exhaust casing (24) is mounted downstream of at least one turbine (22) of the turbomachine, and in which the second end (58) of the conductive element (50) is fixed to a power bar (52) which is fixed to the electric machine (42) mounted downstream of the exhaust casing (24) along the main axis (A) and inside the nozzle.

11. Method for assembling an exhaust casing (24) according to one of claims 1 to 9, characterized in that it comprises at least successively: - a step (ET1) during which the second connection end (58) of the curved power transmission conductive element (50) is presented in front of the hollow arm (48) opening into the outer shell (46), - a step (ET2= during which the conductive element (50) is introduced into the hollow arm (48) while simultaneously imparting to it a tilting movement around a transverse axis along a curved trajectory until the second end emerges from the hollow arm (48) inside the inner shell (44) parallel to the main axis (A) of the exhaust casing (24), - a step (ET4) during which the power transmission conductive element (50) is fixed to the outer shell (46) of the exhaust casing (24).

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