Assembly for a turbine engine

Abstract

The invention relates to an assembly for a turbine engine, having a longitudinal axis (X), said assembly comprising a first structural element (51) comprising a first hole (54) and a second hole (55), and a nut arrangement (60) comprising a retainer (70) fixed to an inner face of said first structural element (51), the holder (70) comprises at least a first recess (72) and a second recess (72) connected to each other by a connecting element (71), the first recess (72) and the second recess (72) each holding a nut (61) aligned with a first hole (54) and a second hole (55) formed through the first structural element (51), respectively, the connecting element (70) is completely or partially adapted to compensate for thermal expansion of the holder (70) that is greater than thermal expansion of the first structural element (51).

Description

Technical Field

[0001] The present description relates to an assembly for a turbine engine. In particular, the present description relates to a turbine engine exhaust cone including such an assembly and to a turbine engine including such an exhaust cone. Background Art

[0002] Conventionally, such as Figure 1 As shown, a turbine engine 10 of the turbofan type having a longitudinal axis comprises, from upstream (AM) to downstream (AV) in the direction of gas circulation in the turbine engine 10: a fan 12, a low-pressure compressor 14a, a high-pressure compressor 14b, a combustion chamber 16, a high-pressure turbine 18a, a low-pressure turbine 18b and an exhaust nozzle 20. The high-pressure compressor 14b and the low-pressure compressor 14a are connected to the high-pressure turbine 18a and the low-pressure turbine 18b, respectively, by corresponding shafts extending in the longitudinal rotation direction of the shaft of the turbine engine. In the following, directional qualifiers such as "longitudinal", "radial" and "circumferential" are defined with reference to the longitudinal axis X.

[0003] The air flow entering the turbine engine is divided downstream of the fan 12 into a main annular air flow entering an annular flow path 22a, called the main path, and a secondary annular air flow entering an annular flow path 22b, called the secondary path, surrounding the main annular flow path 22a. The working parts of the low-pressure compressor 14a and the high-pressure compressor 14b, the combustion chamber 16 and the high-pressure turbine 18a and the low-pressure turbine 18b are located in the main annular flow path 22a.

[0004] Directly at the outlet of the low pressure turbine 28b is an exhaust casing 30. The exhaust casing 30 comprises a radially inner shell 32 and a radially outer shell 34. The annular space formed between the inner shell and the outer shell forms a part of the main flow path 22a at the outlet of the low pressure turbine 18b.

[0005] The exhaust nozzle 20 or propulsion nozzle of the turbine engine 10 comprises an assembly allowing to optimize the flow of the hot gases leaving the turbine. This assembly may also have the function of absorbing at least some of the noise generated by the interaction of these hot gases with the ambient air and with the cold air flow from the fan.

[0006] This assembly includes Figure 22 and 3. The exhaust cone 40 can be seen in FIG. 2, which comprises an upstream portion 40a having a substantially axisymmetric shape about a longitudinal axis X and a downstream portion 40b of conical shape along the longitudinal axis X. The upstream portion 40a comprises a radially outer annular noise reduction wall 42 and a noise reduction enclosure arranged radially inside the annular noise reduction wall. The noise reduction enclosure comprises a radially inner annular wall 44. The radially outer face of the annular noise reduction wall 42 of the upstream portion 40a and the radially inner face of the conical downstream portion 40b together radially internally delimit the main flow path 22a at the exhaust cone 40.

[0007] The inner annular wall 44 and the annular noise reduction wall 42 of the noise reduction enclosure each include a plurality of sectors arranged end to end along the circumference. Two circumferentially adjacent sectors of the inner annular wall 44 or the annular noise reduction wall 42 are screwed to each other. In addition, downstream, the inner annular wall 44 and / or the annular noise reduction wall 42 of the noise reduction enclosure can be screwed to the downstream portion 40b of the exhaust cone 40. Alternatively, downstream, the inner annular wall 44 and / or the annular noise reduction wall 42 of the noise reduction enclosure can be screwed to each other, and one of the inner annular wall 44 and / or the annular noise reduction wall 42 of the noise reduction enclosure can be screwed to the downstream portion 40b of the exhaust cone 40. In order to do this, it is known to use a floating nut device due to the lack of radial access to the interior of the exhaust cone 40.

[0008] Among floating nut devices, a floating nut device is known that includes a retainer that includes a plurality of recesses that each receive a nut. The retainer is fastened to a first structural component that is intended to be screwed to a second structural component so that each nut is aligned with a pair of holes formed through the first structural component and the second structural component, respectively. A screw is then inserted into each pair of holes to be screwed into a corresponding nut held in one of the recesses of the retainer to fasten the first structural component to the second structural component.

[0009] The current trend is to make the inner annular wall 44, the annular noise reduction wall 42 and the tapered downstream portion 40b of the exhaust cone 40 from ceramic matrix composite (CMC) materials, while the retainer of the floating nut device as described above is usually made of metal materials. CMC materials withstand relatively high temperatures and therefore require less cooling. This cooling is traditionally generated by the intake air from the compressor, which affects the efficiency of the turbine engine; CMC materials therefore make it possible to improve engine efficiency and therefore improve fuel consumption. In addition, its use contributes to reducing the mass of the turbine engine. However, the thermal expansion coefficient of the ceramic matrix composite is significantly lower than that of metal. Therefore, when this floating nut device is used at the exhaust cone 40, as the temperature rises during the operation of the turbine engine, the retainer of the floating nut device has a greater thermal expansion than the thermal expansion of the structural element to which it is fixed among the inner annular wall 44, the annular noise reduction wall 42 and the downstream portion 40b of the exhaust cone 40. Mechanical stresses are therefore induced in the structural elements between the inner annular wall 44, the annular noise reduction wall 42 and the downstream portion 40b of the exhaust cone 40, to which the retainer of the floating nut device is fixed at each attachment point of the retainer of the nut device, which mechanical stresses can lead to damage to these elements. Summary of the invention

[0010] An assembly for a turbine engine is provided, having a longitudinal axis, the assembly comprising a first structural element comprising a first hole and a second hole, and a nut device comprising a retainer fixed to an inner face of the first structural element, the retainer comprising at least a first recess and a second recess connected to each other by a connecting element, the first recess and the second recess each retaining a nut aligned with the first hole and the second hole respectively formed through the first structural element, the connecting element being fully or partially suitable for compensating for a thermal expansion greater than that of the first structural element.

[0011] The alignment between each nut and the corresponding hole formed through the first structural element is thus maintained during operation of the turbine engine, in particular when the first structural element and the nut device are subjected to high temperatures. The stresses exerted on the first structural element due to the large thermal expansion of the retainer of the nut device are reduced. Thus, the risk of damage to the first structural element is reduced or even eliminated.

[0012] Each recess may be adapted to retain a respective nut in a floating manner. "Floating" is understood to mean permitting limited movement of the nut in the respective recess of the retainer.

[0013] The first recess and the second recess of the retainer of the nut device may be spaced apart from each other in a first direction, and the connecting element may be fully or partially deformed to compensate for a greater thermal expansion of the retainer between:

[0014] a rest state, wherein the connecting element is subjected to a first temperature and wherein the connecting element assumes a configuration having a first dimension in a second direction perpendicular to the first direction, and

[0015] - an expanded state, wherein the connecting element is subjected to a second temperature higher than the first temperature and wherein the connecting element assumes a configuration having a second dimension in the second direction, the second dimension being different from the first dimension.

[0016] The second dimension may be greater than the first dimension. The connecting element may be a rod extending substantially in the first direction between the first recess and the second recess. The rod may have a thickness suitable for promoting its deformation in the second direction. The thickness of the rod may be less than or equal to 2 mm, preferably less than or equal to 1 mm. In particular, the ratio between the length of the rod and the thickness of the rod in the first direction may be about 100. For example, the rod may have a thickness of about 1 mm and a length of about 100 mm. The connecting element of the nut device may be fully or partially elastically deformable. This makes it possible to limit or even prevent breakage of the connecting element.

[0017] In other words, the connecting element can be configured to have a shape change between a rest state in which the connecting element is subjected to a first temperature and an expanded state in which the connecting element is subjected to a second temperature so as to cause the recesses to separate or expand relative to each other in the first direction. Specifically, the shape change of the connecting element from the rest state to the expanded state can cause the recesses to expand relative to each other in the first direction. Conversely, the shape change of the connecting element from the rest state to the expanded state can cause the recesses to move closer together in the first direction.

[0018] The configuration of the connecting element in the rest state may be a bow in the second direction. The configuration of the connecting element in the expanded state may be a bow in the second direction. The maximum deflection formed by the bowing of the connecting element in the rest state may be less than the maximum deflection formed by the bowing of the connecting element in the expanded state.

[0019] In the rest state and / or in the expanded state, the connecting element may completely or partially have a V-shaped, S-shaped or round cross-section in a plane comprising at least the first direction and preferably the first direction and the second direction.

[0020] The first structural element may be made of a material having a lower thermal expansion coefficient than the material from which the retainer of the nut device is made. Preferably, the thermal expansion coefficient of the material from which the first structural element is made is between 2 and 2.5 times lower than the thermal expansion coefficient of the material from which the retainer of the nut device is made. The first structural element may be made of a ceramic matrix composite material. Such a material has a low density and therefore allows to reduce the mass of the assembly. The retainer of the nut device may be made of a metallic material.

[0021] The assembly may include a second structural element applied to an outer face of the first structural element, the second structural element including a hole aligned with a first hole formed through the first structural element, the second structural element being fixed to the first structural element by a first screw passing through the first hole formed through the first structural element and through the hole formed through the second structural element, the first screw being screwed into a nut retained in a first recess of a retainer of the nut device.

[0022] Thus, when the second structural element is fixed to the first structural element, the retainer is fixed to the inner face of the retainer of the nut device by the connection between the first screw and the nut held in the first recess of the retainer. The first structural element thus does not have any special holes for fixing the retainer of the nut device to the first structural element. This makes it possible to reduce the number of holes made in the first structural element in order to limit damage to the first structural element.

[0023] The assembly may comprise a third structural element applied to the outer face of the first structural element, the third structural element comprising a hole aligned with a second hole formed through the first structural element, the third structural element being fixed to the first structural element by a second screw passing through the second hole formed through the first structural element and through the hole formed through the third structural element, the second screw being screwed into a nut held in a second recess of a retainer of a nut device. Advantageously, this arrangement allows the third structural element to be attached to the first structural element "blindly". In other words, attaching the third structural element to the first structural element requires only access to the outer face of the third structural element in order to insert the second screw into the corresponding hole, the nut being held in place by the retainer of the nut device, in particular being prevented from rotating.

[0024] A gap may be provided between the second structural element and the third structural element in the first direction. This prevents the second structural element and the third structural element from bearing against each other in the first direction and from applying mechanical stresses to each other when they thermally expand during operation of the turbine engine, which could damage them.

[0025] The turbine engine may include an exhaust cone, the exhaust cone including an upstream portion having a substantially axisymmetric shape around a longitudinal axis and a downstream portion of a conical shape along the longitudinal axis, the downstream portion having a cross-section that decreases in the downstream direction. The upstream portion may include, for example, an outer annular noise reduction wall having a plurality of perforations, which defines a radially inner main annular flow path of the turbine engine at the upstream portion of the exhaust cone. The upstream portion of the exhaust cone further includes a noise reduction enclosure radially arranged inside the annular noise reduction wall. The enclosure may include an inner annular wall. The annular noise reduction wall and the inner annular wall may each include a plurality of sectors arranged end to end along a circumference around the longitudinal axis.

[0026] According to a first embodiment, the second structural element may be a first sector among a plurality of sectors of the annular noise reduction wall or the inner annular wall, and the third structural element may be a second sector among a plurality of sectors of the noise reduction wall, the first sector and the second sector being circumferentially adjacent.

[0027] According to a second embodiment, the second structural element may be one of the sectors of the annular noise reduction wall or the inner annular wall, and the third structural element may be the downstream portion of the exhaust cone. Alternatively, the second structural element may be such annular noise reduction wall or such an inner annular wall, provided that these are implemented as one integral piece around the longitudinal axis.

[0028] In the first embodiment and the second embodiment, the first structural element may be a connecting member between the second structural element and the third structural element.

[0029] According to a third embodiment, the first structural element may be one of the sectors of the inner annular wall, the second structural element may be one of the sectors of the annular noise reduction wall, and the third structural element may be the downstream portion of the exhaust cone. Alternatively, the first structural element may be the inner annular wall and the second structural element may be such an annular noise reduction wall, provided that these are implemented as one integral piece around the longitudinal axis.

[0030] In a first embodiment, the first direction may coincide with a circumferential direction around the longitudinal axis.The second direction may coincide with a radial direction relative to the longitudinal axis.

[0031] In the second and third embodiments, the first direction may coincide with the longitudinal direction of the turbine engine. Alternatively, the first direction may include a component in the longitudinal direction and a component in the circumferential direction around the longitudinal axis. Here again, the second direction may coincide with a radial direction relative to the longitudinal axis.

[0032] Embodiments are not excluded in which the second direction coincides with the longitudinal direction or with the circumferential direction around the longitudinal axis. Similarly, embodiments are not excluded in which the second direction comprises a combination of components in one or more directions, in particular a direction among the longitudinal direction, a radial direction relative to the longitudinal axis and a circumferential direction around the longitudinal axis.

[0033] The connecting element of the retainer may include a first portion that is deformable between a rest state and an expanded state, and a second portion that is less deformable than the first portion, the second portion being applied against the inner face of the first structural element, the second portion including a passage, the passage including a guide portion extending in the first direction; the assembly further includes a retaining component fixed relative to the first structural element, the retaining component including a cylindrical portion along the first axis protruding from the inner face of the first structural element, the cylindrical portion passing through the guide portion of the passage formed by the second portion of the connecting element.

[0034] Thus, when the retainer is fixed to the first structural element by screwing the first screw into the nut held in the first recess, and when the third structural element is fixed to the first structural element by screwing the second screw into the nut held in the second recess, a rotation of the retainer of the nut device relative to the first structural element is avoided. In addition, the guide portion of the passage formed through the second part of the connecting element allows the cylindrical portion of the retaining part to move along the passage in the first direction when the retainer thermally expands more than the first structural element during operation of the turbine engine. The guide portion of the passage formed through the second part of the connecting element can have the shape of a slot extending in the first direction.

[0035] The retaining component may include a first retaining portion for retaining in a first direction sensing along a first axis, the first retaining portion being connected to the first end of the cylindrical portion, the first retaining portion having a bearing surface, the bearing surface abutting against the face of the second portion of the connecting element opposite to the first structural element in the direction of the first axis. This allows the second portion of the connecting element to be retained against the inner face of the first structural element. The second portion of the connecting element may be closer to the second recess than the first portion of the connecting element. In other words, the second portion of the connecting element may be arranged between the second recess and the first portion of the connecting element. After the retainer has been fixed to the first structural element by screwing the first screw into the nut retained in the first recess, the retaining component thus allows the alignment between the nut retained in the second recess of the retainer and the second hole formed through the first structural element to be maintained.

[0036] The guide portion of the passage formed through the second portion of the connecting element may have a dimension in a third direction perpendicular to the first direction and the second direction, which dimension is smaller than a dimension of the first holding portion of the retaining member in the third direction.

[0037] The passage formed through the second portion of the connecting element may include an insertion portion adapted to insert the first retaining portion of the retaining member through the passage. The insertion portion may be located at one end of the guide portion of the passage along the first direction.

[0038] The first structural element may include a third hole, and the cylindrical portion of the retaining component passes through the third hole formed through the first structural element. The retaining component includes a second retaining portion for retaining in a second direction sensing along the first axis, and the second retaining portion is connected to the second end of the cylindrical portion. The second retaining portion includes a bearing surface, and the bearing surface abuts against the outer surface of the first structural element in the direction of the first axis.

[0039] The first structural element may include an indentation around the third hole so that the outer face of the first structural element forms a shoulder with which the bearing surface of the second retaining portion contacts. The second retaining portion may be fully received in the indentation. The third structural element may cover the area of ​​the outer face of the first structural element where the indentation is formed.

[0040] According to another aspect, an exhaust cone for a turbine engine is proposed, comprising an assembly as described above. According to another aspect, a turbine engine is proposed, comprising an exhaust cone as described above.

[0041] According to another aspect, a method of assembling an assembly as described above is proposed, the method comprising:

[0042] - applying a retainer of the nut device to the inner face of the first structural element so that the nut retained in the first recess and the nut retained in the second recess are aligned with the first hole and the second hole formed through the first structural element, respectively;

[0043] - Fixing the retainer of the nut arrangement to the first structural element.

[0044] The method may include applying a second structural element to an exterior face of the first structural element such that an aperture formed through the second structural element is aligned with a first aperture formed through the first structural element.

[0045] Securing the retainer of the nut arrangement to the first structural element may include:

[0046] - inserting a first screw through a hole formed through the second structural element and a first hole formed through the first structural element;

[0047] - Screwing the first screw into the nut held in the first recess of the retainer of the nut arrangement.

[0048] In particular, the first screw can be screwed into a nut of a first recess, wherein this recess is located at the first deformable portion side of the connecting element. The first screw can be screwed into the nut of the first recess while being able to access the nut. The force exerted on the nut of the first recess when the first screw is screwed into the nut of the first recess can be counteracted by manually holding the nut in place. In other words, the first nut can be manually prevented from rotating while tightening the first screw.

[0049] The method may include inserting the retaining member into a third hole formed through the first structural element such that a bearing surface of the second retaining portion abuts an outer surface of the first structural element in the direction of the first axis.

[0050] Applying the retainer of the nut arrangement to the interior face of the first structural element may include:

[0051] - inserting the first retaining portion of the retaining member into the insertion portion of the passage formed through the second portion of the connecting element,

[0052] - moving the holder relative to the first structural element along the first direction so as to move the cylindrical portion of the retaining part along the first direction within the guide portion of the passage formed through the second portion of the connecting element and to place the bearing surface of the first retaining portion so that it abuts against the surface of the second portion of the connecting element opposite the first structural element.

[0053] The method may include applying a third structural element to an exterior face of the first structural element such that an aperture formed through the third structural element is aligned with a second aperture formed through the first structural element.

[0054] The method may include:

[0055] - inserting a second screw through the hole formed through the third structural element and the second hole formed through the first structural element;

[0056] - Screwing the second screw into the nut held in the second recess of the retainer of the nut arrangement.

[0057] In particular, the second screw can be screwed into the nut of the second recess, wherein the second recess is located at the second part side of the connecting element. This allows the tightening torque applied to the second screw to be absorbed by the second part of the connecting element, which is less deformable. Screwing the second screw into the nut of the second recess can be carried out "blindly", that is, without access to the nut of the second recess. The force applied to the nut of the second recess when screwing in the second screw can be borne by the edge (i.e., the wall) of the guide part of the passage formed through the second part of the connecting element, which second part abuts against the cylindrical part of the retaining part in the third direction. In other words, it is not necessary to intervene manually to prevent the rotation of the nut of the second recess when screwing in the second screw. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Other features, details and advantages will become apparent upon reading the following detailed description and upon examining the accompanying drawings, in which:

[0059] Figure 1 is a partial schematic half view in axial section of a turbine engine of the prior art;

[0060] Figure 2 yes Figure 1 A schematic perspective view of an exhaust cone of a turbine engine;

[0061] Figure 3 Include Figure 3 a and 3b, each showing a schematic perspective view of an exhaust cone according to the present description;

[0062] Figure 4 is a perspective view showing an assembly of a first structural element, a second structural element and a third structural element, wherein the first structural element, the second structural element and the third structural element are connected by means of Figure 3 The exhaust cone is fixed together by a nut device implemented in the exhaust cone;

[0063] Figure 5 yes Figure 4 A perspective view of a nut device;

[0064] Figure 6 The invention includes a holding member. Figure 4 A perspective view of a portion of a nut device Figure 6 a, and shows Figure 6 A holding part Figure 6 b;

[0065] Figure 7 Include Figure 7 a and 7b, each showing the difference between the static state and the expanded state, respectively. Figure 4 A schematic cross-sectional view of an assembly of;

[0066] Figure 8 Include Figure 8 a and 8b, which each show Figure 5 A perspective view of an alternative embodiment of a nut recess of a nut device;

[0067] Fig. 9 Include Fig. 9 a to 9e, which schematically represent the assembly Figure 4 The method of assembling components. DETAILED DESCRIPTION

[0068] Reference now Figure 3 . Figure 3 An exhaust cone 40 for a turbine engine having a longitudinal axis X is shown. In the following, directional qualifiers, such as "longitudinal", "radial" or "circumferential", are defined with reference to the longitudinal axis X. The exhaust cone 40 comprises an upstream portion 40a having a substantially axisymmetric shape about the longitudinal axis X, and a downstream portion 40b of a conical shape along the longitudinal axis X, the downstream portion having a cross-section that decreases in the downstream direction. The upstream portion 40a comprises, for example, an outer annular noise reduction wall 42 having a plurality of perforations, the outer annular noise reduction wall being intended to define a radially inner annular main flow path of the turbine engine. The upstream portion 40a of the exhaust cone 40 further comprises a noise reduction enclosure arranged radially inside the annular noise reduction wall 42. The enclosure is internally composed of Figure 3 According to the example shown, the annular noise reduction wall 42 comprises two sectors ("half shells") arranged circumferentially end to end around the longitudinal axis X. Moreover, the inner annular wall 44 is here embodied as one integral piece around the longitudinal axis X.

[0069] like Figure 3 As can be seen in FIG. a, the annular noise reduction wall 42, the inner annular wall 44 and the downstream portion 40b are assembled together by a plurality of nut devices 60. Similarly, as in Figure 3 As can be seen in b, the two sectors of the annular noise reduction wall 42 are connected to each other by means of a connecting piece 46 and a further plurality of nut means 60 .

[0070] Reference below Figures 4 to 9 The nut arrangement 60 is described in more detail.

[0071] Figure 4 An assembly for a turbine engine is shown, comprising a first structural element 51, a second structural element 52 and a third structural element 53. The assembly further comprises a nut device 60 for connecting the first structural element 51, the second structural element 52 and the third structural element 53 together.

[0072] The first structural element 51 includes a first hole 54 and a second hole 55. The first hole 54 and the second hole 55 are spaced apart from each other in the first direction d1. The first structural element 51 has an inner face and an outer face.

[0073] The second structural element 52 and the third structural element 53 are each applied against the outer face of the first structural element 51. The second structural element 52 and the third structural element 53 are spaced apart from each other in the first direction d1. The second structural element 52 includes a hole 57 aligned with the first hole 54 formed through the first structural element 51. Similarly, the third structural element 53 includes a hole 58 aligned with the second hole 55 formed through the first structural element 51.

[0074] The nut device 60 first includes a retainer 70. The retainer 70 is fixed to the inner face of the first structural element 51. The retainer 70 includes at least a first recess 72 and a second recess 72 connected to each other by a connecting element 71. The first recess 72 and the second recess 72 each retain the nut 61 (in the case of a first hole 54 and a second hole 55 formed through the first structural element 51, respectively) aligned with each other. Figure 5 The first recess 72 and the second recess 72 of the retainer 70 of the nut device 60 are therefore also spaced apart from each other in the first direction d1. Here, the connecting element 71 is a rod extending between the first recess 72 and the second recess 72 substantially in the first direction d1.

[0075] Each recess 72 may be capable of retaining a corresponding nut 61 in a floating manner. "Floating" should be understood to mean allowing limited movement of the nut 61 within its corresponding recess 72 of the retainer 70. Each recess 72 includes a base 79 and a plurality of tabs 80 protruding from (formed by) the base 79. The base 79 has a hole 81. Each nut 61 is arranged on the base 79 of its corresponding recess 72 while being aligned with the hole 81 formed through the base 79. Through the shape complementarity between each tab 80 of the recess 72 and the relief 62 formed on the periphery of the nut 61, each nut 61 is retained in its corresponding recess 72 in a floating manner. According to Figure 4 , 6 8a, each tab 80 of the recess 72 engages in the inward embossment 62 formed on the periphery of the nut 61. In the first variant embodiment, each recess 72 includes three tabs 80. Figure 8 In the second variant embodiment of the first recess 72 and the second recess 72 shown in FIG. 1 , each tab 80 has an inward embossment, in which the protruding embossment 62 formed on the periphery of the nut 61 engages. Here, the protruding embossment 62 is a rib. In the second variant embodiment, each recess 72 includes two tabs 80.

[0076] The second structural element 52 is fixed to the first structural element 51 by means of a first screw 63 which passes through a first hole 54 formed through the first structural element 51 and a hole 57 formed through the second structural element 52. The first screw 63 is screwed into a nut 61 held in a first recess 72 of a retainer 70 of a nut device 60. The retainer 70 is thus fixed to the inner face of the first structural element 51 by the connection between the first screw 63 and the nut 61 held in the first recess 72 of the retainer 70, which also ensures the fixing of the second structural element 52 to the first structural element 51. The first structural element 51 then does not have any specific hole for fixing the retainer 70 of the nut device 60 to the first structural element 51. This makes it possible to reduce the number of holes made in the first structural element 51 so as to limit the risk of damage to the first structural element 51.

[0077] The third structural element 53 is fixed to the first structural element 51 by a second screw 63 which passes through a second hole 55 formed through the first structural element 51 and a hole 58 formed through the third structural element 53. The second screw 63 is screwed into the nut 61 held in the second recess 72 of the retainer 70 of the nut device 60.

[0078] According to the first embodiment, the second structural element 52 is one of the sectors of the annular noise reduction wall 42, and the third structural element 53 is the other of the sectors of the annular noise reduction wall 42. According to the first embodiment, the first structural element 51 is a connecting piece 46 connecting two sectors of the annular noise reduction wall 42. In the first embodiment, the first direction d1 coincides with the circumferential direction around the longitudinal axis X.

[0079] According to the second embodiment, the first structural element 51 is the inner annular wall 44, the second structural element 52 is one of the sectors of the annular noise reduction wall 42, and the third structural element 53 is the downstream portion 40b of the exhaust cone 40. In the second embodiment, the first direction d1 includes a component in the longitudinal direction and a component in the circumferential direction around the longitudinal axis X.

[0080] In each of the first and second embodiments, a second direction d2 perpendicular to the first direction d1 is defined. The second direction d2 here coincides with a radial direction relative to the longitudinal axis X. Finally, a third direction d3 perpendicular to the first and second directions d1 and d2 is also defined.

[0081] In each of the first and second embodiments, the first structural element 51 is made of a ceramic matrix composite material. The second structural element 52 and the third structural element 53 are also made of a ceramic matrix composite material. Such a material has a low density and thus allows the mass of the assembly to be reduced. In contrast, the retainer 70 of the nut device 60 is made of a metal material. Therefore, the first structural element 51 is made of a material having a lower thermal expansion coefficient than the thermal expansion coefficient of the material from which the retainer 70 of the nut device 60 is made.

[0082] Therefore, if Figure 7 As shown in a, when the turbine engine is not in operation, the assembly is subjected to a first temperature, and the first hole 54 and the second hole 55 formed through the first structural element 51 are spaced apart at a first spacing L1 along the first direction d1. And, the first recess 72 and the second recess 72 of the retainer 70 of the nut device 60 are also spaced apart at a first spacing L1 along the first direction d1. However, when the turbine engine is in operation, the assembly is subjected to a second temperature, which is higher than the first temperature due to the hot gas circulation in the turbine engine. Therefore, the first structural element 51 expands, and the first hole 54 and the second hole 55 formed through the first structural element 51 are spaced apart at a second spacing L2 along the first direction d1. The second spacing L2 is greater than the first spacing L1. Since the retainer 70 is attached to the first structural element 51 by the connection between the screw 63 and the nut 62, the spacing between the first recess 72 and the second recess 72 of the retainer 70 of the nut device 60 in the first direction is constrained to the second spacing L2 in the first direction d1. However, the retainer 70 is subject to high thermal expansion, which causes mechanical stresses in each tightening between one of the nuts 62 and the corresponding screw 63 and, in turn, in the first structural element 51 .

[0083] To overcome this problem, the connection element 71 comprises a first portion 73 adapted to compensate for the thermal expansion of the retainer 70, which is greater than the thermal expansion of the first structural element 51. The alignment between each nut 61 and its respective hole 54, 55 formed through the first structural element 51 is thus maintained during operation of the turbine engine, in particular when the first structural element 51 and the nut device 60 are subjected to high temperatures. The stresses exerted on the first structural element 51 due to the higher thermal expansion of the retainer 70 of the nut device 60 are further reduced. Therefore, the risk of damage to the first structural element 51 is reduced or even eliminated.

[0084] For this purpose, refer to Figure 7 , the first portion 73 of the connecting element 71 can be elastically deformed in order to compensate for the larger thermal expansion of the retainer 70. The first portion 73 of the connecting element can be deformed between the following states:

[0085] -Stationary state( Figure 7a), wherein the connecting element 71 is subjected to a first temperature and wherein the first portion 73 of the connecting element 71 is in a configuration having a first dimension D1 in the second direction d2, and

[0086] -Expansion state ( Figure 7 b) wherein the connection element 71 is subjected to a second temperature higher than the first temperature and wherein the first portion 73 of the connection element 71 is in a configuration having a second dimension D2 in the second direction d2.

[0087] like Figure 7 As can be seen, the second dimension D2 of the first portion 73 of the connecting element 71 in the expanded state is greater than the first dimension D1 of the first portion 73 of the connecting element 71 in the rest state.

[0088] In particular, the configuration of the first portion 73 of the connecting element 71 in the rest state and in the expanded state is a bow in the second direction d2. The maximum deflection formed by the bow of the first portion 73 of the connecting element 71 in the rest state may be less than the maximum deflection formed by the bow of the first portion 73 of the connecting element 71 in the expanded state. The connecting element may have a thickness suitable for promoting its deformation in the second direction d2. The thickness of the connecting element may be less than or equal to 2 mm.

[0089] A gap in the first direction d1 is also provided between the second structural element 52 and the third structural element 53. This allows preventing the second structural element 52 and the third structural element 53 from bearing against each other in the first direction d1 and from applying mechanical stresses to each other when they thermally expand during operation of the turbine engine, which could damage them.

[0090] Furthermore, the connecting element 71 of the retainer 70 includes a second portion 74 which is less deformable than the first portion 73. It is worth noting that the second portion 74 of the connecting element 71 is closer to the second recess 72 than the first portion 73 of the connecting element 71. Figure 6 The second portion 74 is applied against the inner face of the first structural element 51. The second portion 74 comprises a passage 75. The passage 75 comprises a guide portion 76 extending in the first direction d1. The guide portion 76 of the passage 75 formed through the second portion 74 of the connecting element 71 has the shape of a slot extending in the first direction d1.

[0091] The assembly further comprises Figure 66a and 6b more particularly visible holding member 90. Holding member 90 is fixed relative to the first structural element 51. Holding member 90 comprises a cylindrical portion 91 protruding from the inner face of the first structural element 51 along the first axis A1. The first axis A1 extends along the second direction d2. The cylindrical portion 91 passes through the guide portion 76 of the passage 75 formed by the second portion 74 of the connecting element 71. Therefore, when the retainer 70 is fixed to the first structural element 51 by screwing the first screw 63 into the nut 61 held in the first recess 72, and in particular when the third structural element 53 is fixed to the first structural element 51 by screwing the second screw 63 into the nut 61 held in the second recess 72, the rotation of the retainer 70 of the nut device 60 relative to the first structural element 51 is avoided. Furthermore, the guide portion 76 of the passage 75 formed through the second portion 74 of the connecting element 71 allows the cylindrical portion 91 of the retaining member 90 to move in the passage 75 along the first direction when the retainer 70 thermally expands more than the first structural element 51 during operation of the turbine engine.

[0092] The retaining member 90 further comprises a first retaining portion 92 for retaining in the first direction sensing S1 along the first axis A1, which is connected to the first end of the cylindrical portion 91. The first retaining portion 92 has a bearing surface which abuts against the surface of the second portion 74 of the connecting element 71 opposite to the first structural element 51 in the direction of the first axis A1. This makes it possible to retain the second portion 74 of the connecting element 71 applied against the inner face of the first structural element 51. The retaining member 90 allows the alignment between the nut 61 retained in the second recess 72 of the retainer 70 and the second hole 55 formed through the first structural element 51 to be maintained, in particular after the retainer 70 has been fixed to the first structural element 51 by screwing the first screw 63 into the nut 61 retained in the first recess 72.

[0093] The guide portion 76 of the passage 75 formed through the second portion 74 of the connecting element 71 has a dimension in the third direction d3 that is smaller than the dimension in the third direction d3 of the first retaining portion 92 of the retaining member 90. This prevents the first retaining portion 92 from being removed from the retaining member 90 via the guide portion 76 of the passage 75 in the first direction sensing S1 along the first axis A1.

[0094] The passage 75 formed through the second portion 74 of the connecting element 71 includes an insertion portion 77 adapted to insert the first retaining portion 92 of the retaining member 90 into the passage 75 formed through the connecting element 71. The insertion portion 77 is located at one end of the guide portion 76 of the passage 75 along the first direction d1.

[0095] The cylindrical portion 91 of the holding member 90 also passes through the third hole 56 formed through the first structural element 51. The holding member 90 includes a second holding portion 93 for holding in the second direction sense S2 along the first axis A1, which is connected to the second end of the cylindrical portion 91. The second holding portion 93 includes a bearing surface that abuts against the outer surface of the first structural element 51 along the direction of the first axis A1.

[0096] The first structural element 51 in particular comprises an indentation around the third hole 56, so that the outer face of the first structural element 51 forms a shoulder, with which the bearing face of the second retaining portion 93 contacts. The second retaining portion 93 is then completely received in the indentation. The third structural element 53 can thus cover the area of ​​the outer face of the first structural element 51 in which the indentation is formed.

[0097] Now more specifically refer to Fig. 9 , which schematically represents a method of assembling an assembly for a turbine engine as described above.

[0098] The method comprises Fig. 9 The first step can be seen in a. The first step consists in applying the second structural element 52 on the outer face of the first structural element 51 so that the holes 57 formed through the second structural element 52 are aligned with the first holes 54 formed through the first structural element 51 .

[0099] The method comprises Fig. 9 b. The second step consists in inserting the retaining member 90 into the third hole 56 formed through the first structural element 51 so that the bearing surface of the second retaining portion 93 abuts against the outer face of the first structural element 51 in the direction of the first axis A1. The second retaining portion 93 is in particular completely housed in the recess in the first structural element 51.

[0100] The method comprises Fig. 9 The third step comprises applying the retainer 70 of the nut device 60 to the inner face of the first structural element 51 so that the nut 61 retained in the first recess 72 and the nut 61 retained in the second recess 72 are aligned with the first hole 54 and the second hole 55 formed through the first structural element 51, respectively.

[0101] To this end, applying the retainer 70 of the nut device 60 to the inner face of the first structural element 51 comprises:

[0102] - inserting the first retaining portion 92 of the retaining member 90 into the insertion portion 77 of the passage 75 formed through the second portion 74 of the connecting element 71,

[0103] - Moving the holder 70 relative to the first structural element 51 along the first direction d1 as indicated by the arrow F.

[0104] This allows the cylindrical portion 91 of the retaining member 90 to be moved along the first direction within the guide portion 76 of the passage 75 formed through the second portion 74 of the connecting element 71 and to place the bearing surface of the first retaining portion 92 so that it abuts against the face of the second portion 74 of the connecting element 71 opposite the first structural element 51.

[0105] The method comprises Fig. 9 The fourth step is visible in d. The fourth step consists in fixing the retainer 70 of the nut device 60 to the first structural element 51 .

[0106] Securing the retainer 70 of the nut device 60 to the first structural element 51 may include:

[0107] - inserting the first screw 63 through the hole 57 formed through the second structural element 52 and the first hole 54 formed through the first structural element 51;

[0108] The first screw 63 is screwed into the nut 61 held in the first recess 72 of the holder 70 of the nut device 60 .

[0109] The method comprises Fig. 9 The fifth step can be seen in e. The fifth step includes:

[0110] - applying the third structural element 53 to the outer face of the first structural element 51 so that the hole 58 formed through the third structural element 53 is aligned with the second hole 55 formed through the first structural element 51;

[0111] - inserting the second screw 63 through the hole 58 formed through the third structural element 53 and the second hole 55 formed through the first structural element 51;

[0112] The second screw 63 is screwed “blindly” into the nut 61 held in the second recess 72 of the holder 70 of the nut device 60 .

[0113] Here, the retaining member 90 fulfills the anti-rotation function of the nut 61 with respect to the second recess 72 during the screwing of the second screw 63 .

Claims

1. An assembly for a turbine engine, having a longitudinal axis (X), said assembly comprising a first structural element (51) comprising a first hole (54) and a second hole (55), and a nut device (60), said first structural element (51) comprising a first hole (54) and a second hole (55), said nut device (60) comprising a retainer (70) fixed to an inner face of said first structural element (51), said retainer (70) comprising at least a first recess (72) and a second recess (72) connected to each other by a connecting element (71), said first recess (72) and said second recess (72) each retaining a nut (61) aligned with a first hole (54) and a second hole (55) respectively formed through said first structural element (51), said connecting element (71) being fully or partially suitable for compensating for thermal expansion of the retainer (70) greater than thermal expansion of said first structural element (51).

2. Assembly according to the preceding claim, characterized in that The first recess (72) and the second recess (72) of the retainer (70) of the nut device (60) are spaced apart from each other in a first direction (d1), and the connecting element (71) is fully or partially deformable to compensate for a greater thermal expansion of the retainer (70) between the following states: a static state, wherein the connecting element (71) is subjected to a first temperature and wherein the connecting element (71) is in a configuration having a first dimension (D1) in a second direction (d2) perpendicular to the first direction (d1), and - an expanded state, wherein the connecting element (71) is subjected to a second temperature higher than the first temperature and wherein the connecting element (71) is in a configuration having a second dimension (D2) in the second direction (d2), the second dimension (D2) being different from the first dimension (D1).

3. The assembly according to claim 2, characterized in that The configuration of the connecting element (71) in the rest state is bowed in the second direction (d2) and / or the configuration of the connecting element (71) in the expanded state is bowed in the second direction (d2).

4. The claim according to any one of the preceding claims, characterized in that The first structural element (51) is made of a material having a thermal expansion coefficient lower than the thermal expansion coefficient of the material of which the retainer (70) of the nut device (60) is made.

5. An assembly according to any preceding claim, characterised in that The assembly comprises a second structural element (52) applied to the outer face of the first structural element (51), the second structural element (52) comprising a hole (57) aligned with a first hole (54) formed through the first structural element (51), the second structural element (52) being fixed to the first structural element (51) by a first screw (63) passing through the first hole (54) formed through the first structural element (51) and through the hole (57) formed through the second structural element (52), the first screw (63) being screwed into a nut (61) held in a first recess (72) of a retainer (70) of the nut device (60).

6. Assembly according to the preceding claim, characterized in that The assembly comprises a third structural element (53) applied to the outer face of the first structural element (51), the third structural element (53) comprising a hole (58) aligned with a second hole (55) formed through the first structural element (51), the third structural element (53) being fixed to the first structural element (51) by a second screw (63) passing through the second hole (55) formed through the first structural element (51) and through the hole (58) formed through the third structural element (53), the second screw (63) being screwed into a nut (61) held in a second recess (72) of a retainer (70) of the nut device (60).

7. An assembly according to any one of claims 2 to 6, characterized in that The connecting element (71) of the retainer (70) comprises a first portion (73) capable of deforming between the rest state and the expanded state, and a second portion (74) capable of deforming less than the first portion (73), the second portion (74) being applied against the inner face of the first structural element (51), the second portion (74) comprising a passage (75), the passage comprising a guide portion (76) extending in the first direction (d1), the assembly further comprising a retaining member (90) fixed relative to the first structural element (51), the retaining member (90) comprising a cylindrical portion (91) protruding from the inner face of the first structural element (51) along the first axis (A1), the cylindrical portion (91) passing through the guide portion (76) of the passage (75) formed by the second portion (74) of the connecting element (71).

8. Assembly according to the preceding claim, characterized in that The retaining member (90) comprises a first retaining portion (92) for retaining in a first direction sensing (S1) along the first axis (A1), the first retaining portion being connected to a first end of the cylindrical portion (91), the first retaining portion (92) having a bearing surface, the bearing surface abutting against a surface of a second portion (74) of the connecting element (71) opposite to the first structural element (51) in the direction of the first axis (A1).

9. The assembly according to claim 7 or 8, characterized in that The first structural element (51) comprises a third hole (56), and the cylindrical portion (91) of the retaining component (90) passes through the third hole (56) formed through the first structural element (51), and the retaining component (90) comprises a second retaining portion (93) for retaining in a second direction sensing (S2) along the first axis (A1), the second retaining portion being connected to the second end of the cylindrical portion (91), and the second retaining portion (93) comprising a bearing surface, and the bearing surface abuts against an outer surface of the first structural element (51) in the direction of the first axis (A1).

10. A method of assembling an assembly according to any one of the preceding claims, the method comprising: - applying the retainer (70) of the nut device (60) to the inner face of the first structural element (51) so that the nut (61) retained in the first recess (72) and the nut (61) retained in the second recess (72) are aligned with the first hole (54) and the second hole (55) formed through the first structural element (51), respectively; - Fixing the retainer (70) of the nut device (60) to the first structural element (51).

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