Assembly for a turbine engine

Abstract

The invention relates to an assembly for a turbine engine having a longitudinal axis (X), the assembly comprising a first structural element (51) and a nut device (60), the first structural element (51) comprising a first hole (54) and a second hole (55), the nut device (60) comprising a mounting (70) attached to an inner face of the first structural element (51), the mounting (70) comprising at least a first recess (72) and a second recess (72) connected to one another by a connecting element (71), the first recess (72) and the second recess (72) each retaining a nut (61) respectively aligned with the first hole (54) and the second hole (55) formed through the first structural element (51), the connecting element (70) being, in full or in part, adapted to compensate for a thermal expansion of the mounting (70) that is greater than a thermal expansion of the first structural element (51).

Description

Description Title: TURBOMACHINE SET technical field

[0001] This description relates to a turbomachine assembly. In particular, this description relates to a turbomachine ejection cone comprising such an assembly and to a turbomachine comprising such an ejection cone. Previous technique

[0002] Typically, as shown in Figure 1, a longitudinally oriented turbofan engine 10 comprises, from upstream to downstream in the direction of gas flow within the turbofan 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 a high-pressure turbine 18a and a low-pressure turbine 18b, respectively, by a shaft extending along the longitudinal direction of rotation of the turbofan engine shafts. Hereafter, orientation qualifiers such as "longitudinal," "radial," and "circumferential" are defined with reference to the longitudinal axis X.

[0003] The airflow entering the turbomachine is divided, downstream of the fan 12, into a primary annular airflow entering an annular duct 22a, called the primary duct, and a secondary annular airflow entering an annular duct 22b, called the secondary duct, which surrounds the primary annular air duct 22a. 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, for the working parts, in the primary annular duct 22a.

[0004] An exhaust casing 30 is located directly at the outlet of the low-pressure turbine 28b. The exhaust casing 30 comprises a radially internal ferrule 32 and a radially external ferrule 34. An annular space formed between the internal ferrule and the external ferrule forms part of the primary stream 22a at the outlet of the low-pressure turbine 18b.

[0005] The exhaust nozzle 20, or ejection nozzle, of the turbomachine 10 includes an assembly for optimizing the flow of hot gases from the turbine. This assembly may also serve to absorb at least some of the noise generated by the interaction of these hot gases with the ambient air and with the flow of cold air from the blower.

[0006] This assembly includes an ejection cone 40, visible in Figure 2, which comprises an upstream portion 40a, substantially axisymmetric about the longitudinal axis X, and a downstream portion 40b, conical about the longitudinal axis X. The upstream portion 40a includes a radially external annular acoustic wall 42 and an acoustic box arranged radially inside the annular acoustic wall. The acoustic box includes a radially internal annular wall 44. The radially external face of the annular acoustic wall 42 of the upstream portion 40a and the radially external face of the conical downstream portion 40b define, radially within, the primary channel 22a, at the level of the ejection cone 40.

[0007] The inner annular wall 44 of the acoustic enclosure and the annular acoustic wall 42 each comprise a plurality of sectors arranged circumferentially end to end. Two circumferentially adjacent sectors of the inner annular wall 44, or of the annular acoustic wall 42, are screwed together. Furthermore, downstream, the internal annular wall 44 of the acoustic enclosure and / or the annular acoustic wall 42 can be screwed to the downstream portion 40b of the ejection cone 40. Alternatively, downstream, the internal annular wall 44 of the acoustic enclosure and / or the annular acoustic wall 42 can be screwed together, and one of the internal annular walls 44 of the acoustic enclosure and / or the annular acoustic wall 42 can be screwed to the downstream portion 40b of the ejection cone 40. To achieve this, it is known to use floating nut devices due to the lack of radial access to the inside of the ejection cone 40.

[0008] Among floating nut devices, one is known that comprises a bracket with multiple housings, each holding a nut. The bracket is attached to a first structural element, which is intended to be screwed to a second structural element, such that each nut is aligned with a pair of holes formed through the first and second structural elements, respectively. A screw is then inserted into each pair of holes and screwed into the respective nut held in one of the bracket's housings, thus fixing the first structural element to the second.

[0009] The current trend is to make the inner annular wall 44, the annular acoustic wall 42, and the downstream conical portion 40b of the ejection cone 40 from ceramic matrix composite (CMC), while the support for a floating nut device as described above is generally made of a metallic material. CMC materials withstand relatively high temperatures and therefore require less Cooling. Since this cooling is traditionally achieved by drawing heat from the compressor, which impacts the turbomachine's efficiency, CMC materials improve engine efficiency and consequently fuel consumption. Furthermore, their use contributes to reducing the mass of turbomachines. However, the coefficient of thermal expansion of a ceramic matrix composite material is significantly lower than that of a metallic material. Therefore, when such a floating nut device is used at the exhaust cone 40, during the turbomachine's operating temperature rise, the floating nut support exhibits greater thermal expansion than the structural element to which it is attached, namely the internal annular wall 44, the annular acoustic wall 42, and the downstream portion 40b of the exhaust cone 40.As a result, mechanical stresses are induced in the structural element between the internal annular wall 44, the annular acoustic wall 42 and the downstream part 40b of the ejection cone 40 to which the floating nut device support is attached, at each attachment point of the nut device support, which can lead to damage to these elements. Summary

[0010] A longitudinal axis turbomachine assembly is proposed, the assembly comprising a first structural element and a nut device, the first structural element comprising a first hole and a second hole, the nut device comprising a support fixed to an internal face of the first structural element, the support comprising at least a first housing and a second housing connected to each other by a connecting element, the first housing and the second housing each retaining a nut aligned respectively with the first hole and the second hole formed through the first structural element, the connecting element being, in whole or in part, adapted to compensate for a thermal expansion of the support greater than a thermal expansion of the first structural element.

[0011] Thus, the alignment between each nut and its corresponding hole through the first structural element is maintained during turbomachine operation, particularly when the first structural element and the nut assembly are subjected to high temperatures. Furthermore, the stresses exerted on the first structural element due to the greater thermal expansion of the nut assembly support are reduced. Consequently, the risk of damage to the first structural element is minimized or even eliminated.

[0012] Each housing can be adapted to retain the respective nut in a floating manner. By "floating," we mean that limited movement of the nut within the respective housing of the support is permitted.

[0013] The first and second housings of the nut device support can be spaced apart in a first direction, the connecting element being, in whole or in part, deformable to compensate for the greater thermal expansion of the support between: - a rest state in which the bonding element is subjected to a first temperature and in which the bonding element exhibits a conformation having a first dimension along a second direction perpendicular to the first direction, and - a dilated state in which the bonding element is subjected to a second temperature which is higher than the first temperature and in which the bonding element has a conformation having a second dimension in the second direction, the second dimension being different from the first dimension.

[0014] The second dimension may be larger than the first. The connecting element may be a rod extending primarily in the first direction between the first and second housings. The rod may have a thickness adapted to facilitate its deformation in the second direction. The rod thickness may be less than or equal to 2 mm, preferably less than or equal to 1 mm. In particular, the ratio between the rod's length in the first direction and its thickness may be on the order of 100. For example, the rod may have a thickness of approximately 1 mm and a length of approximately 100 mm. The connecting element of the nut device may be, in whole or in part, elastically deformable. This helps to limit, or even prevent, breakage of the connecting element.

[0015] In other words, the connecting element can be configured to exhibit a change in shape between its rest state, in which it is subjected to the first temperature, and its expanded state, in which it is subjected to a second temperature, such as to move the housings apart or apart in the first direction. Specifically, the change in shape of the connecting element from its rest state to its expanded state can move the housings apart in the first direction. Conversely, the change in shape of the connecting element from its rest state to its expanded state can move the housings closer together in the first direction.

[0016] The conformation of the connecting element in the rest state can be a deflection along the second direction. The conformation of the connecting element in the dilated state can also be a deflection along the second direction. The maximum deflection formed by the deflection of the connecting element in the rest state may be less than the maximum deflection formed by the deflection of the connecting element in the dilated state.

[0017] In the rest state and / or in the dilated state, the connecting element may have, in whole or in part, a section having a V, S or arc of a circle shape in a plane which includes at least the first direction, and preferably which includes the first and second directions.

[0018] The first structural element can be made of a material whose coefficient of thermal expansion is lower than the coefficient of thermal expansion of the material used to support the nut. Preferably, the coefficient of thermal expansion of the material used for the first structural element is between 2 and 2.5 times lower than the coefficient of thermal expansion of the material used to support the nut. The first structural element can be made of a ceramic matrix composite material. Such materials have a low density, thus allowing for a reduction in the overall mass. The support for the nut can be made of a metallic material.

[0019] The assembly may include a second structural element applied to an external face of the first structural element, the second structural element having a hole aligned with the first hole formed through the first structural element, the second structural element being fixed to the first structural element by a first screw which passes through the first hole formed through the first structural element and the hole formed through the second structural element, the first screw being screwed into the nut retained in the first housing of the nut device support.

[0020] The bracket is thus fixed to the inner face of the nut device support by the connection between the first screw and the nut held in the first slot of the bracket when the second structural element is attached to the first structural element. The first structural element then lacks specific holes for attaching the nut device support to it. This reduces the number of holes drilled in the first structural element, thereby minimizing damage to it.

[0021] The assembly may include a third structural element applied to an external face of the first structural element, the third structural element having a hole aligned with the second hole formed through the first structural element, the third structural element being fixed to the first structural element by a second screw which passes through the second hole formed through the first structural element and the hole formed through the third structural element, the second screw being screwed into the nut. retained in the second housing of the nut support. Advantageously, this arrangement allows for the "blind" fastening of the third structural element to the first structural element. In other words, fastening the third structural element to the first structural element only requires access to an external face of the third structural element to insert the second screw into the corresponding holes, the nut being held in position, and in particular prevented from rotating, by the nut support.

[0022] A gap can be provided in the first direction between the second and third structural elements. This prevents the second and third structural elements from bearing against each other in the first direction and exerting mechanical stresses on each other when they expand thermally during the operation of the turbomachine, which could damage them.

[0023] The turbomachine may include an ejection cone comprising an upstream portion substantially axisymmetric about its longitudinal axis and a downstream portion conical about its longitudinal axis with a cross-section decreasing downstream. The upstream portion may include an external annular acoustic wall, for example, multi-perforated, which radially delimits a primary annular flow of the turbomachine within the upstream portion of the ejection cone. The upstream portion of the ejection cone further includes an acoustic box arranged radially within the annular acoustic wall. The box may include an internal annular wall. Both the annular acoustic wall and the internal annular wall may comprise a plurality of sectors arranged circumferentially end-to-end about the longitudinal axis.

[0024] According to a first embodiment, the second structural element can be a first sector among the plurality of sectors of the annular acoustic wall or the internal annular wall and the third structural element can be a second sector among the plurality of sectors of the acoustic wall, the first sector and the second sector being circumferentially adjacent.

[0025] According to a second embodiment, the second structural element may be one of the plurality of sectors of the annular acoustic wall or the internal annular wall, and the third structural element may be the downstream part of the discharge cone. Alternatively, the second structural element may be the annular acoustic wall itself or the internal annular wall itself, provided that these are constructed as a single unit around the longitudinal axis.

[0026] In the first embodiment and the second embodiment, the first structural element can be a connecting piece between the second structural element and the third structural element.

[0027] According to a third embodiment, the first structural element may be one of the plurality of sectors of the inner annular wall, the second structural element may be one of the plurality of sectors of the annular acoustic wall, and the third structural element may be the downstream part of the discharge cone. Alternatively, the first structural element may be the inner annular wall and the second structural element may be the annular acoustic wall itself, provided that these are constructed as a single unit around the longitudinal axis.

[0028] In the first embodiment, the first direction can coincide with a circumferential direction around the longitudinal axis. The second direction can coincide with a radial direction with respect to the longitudinal axis.

[0029] In the second and third embodiments, the first direction can coincide with the longitudinal direction of the turbomachine. Alternatively, the first direction can include a component along the longitudinal direction and a component along the circumferential direction around the longitudinal axis. Here too, the second direction can coincide with a radial direction with respect to the longitudinal axis.

[0030] An embodiment in which the second direction coincides with the longitudinal direction or with the circumferential direction around the longitudinal axis is not excluded. Similarly, an embodiment in which the second direction comprises a combination of components along one or more directions is not excluded, including the longitudinal direction, the radial direction with respect to the longitudinal axis, and the circumferential direction around the longitudinal axis.

[0031] The connecting element of the support may include a first part which is deformable between the rest state and the dilated state, and a second part less deformable than the first part, the second part being applied against the inner face of the first structural element, the second part having a passage which includes a guide part extending in the first direction, the assembly further including a retaining member which is fixed relative to the first structural element, the retaining member including a cylindrical portion along a first axis which protrudes from the inner face of the first structural element, the cylindrical portion passing through the guide part of the passage formed through the second part of the connecting element.

[0032] Rotation of the nut support relative to the first structural element is thus prevented, firstly, when the support is attached to the first structural element by tightening a first screw into the nut held in the first housing, and secondly, when the third structural element is attached to the first structural element by tightening a second screw into the nut held in the second housing. Furthermore, the guide portion of the passage formed through the second part of the connecting element allows the cylindrical portion of the retaining member to move along the first direction within the passage when the support expands thermally more than the first structural element during turbomachine operation. The guide portion of the passage formed through the second part of the connecting element can be shaped like a slot extending along the first direction.

[0033] The retaining element may include a first retention portion, oriented along the first axis, connected to a first end of the cylindrical portion. This first retention portion has a bearing face, oriented along the first axis, against a face of the second portion of the connecting element that is opposite the first structural element. This allows the second portion of the connecting element to be held against the inner face of the first structural element. The second portion of the connecting element may be closer to the second housing than the first portion. In other words, the second portion of the connecting element may be positioned between the second housing and the first portion of the connecting element.The retaining device thus makes it possible to maintain the alignment between the nut held in the second housing of the support and the second hole formed through the first structural element after the support is fixed to the first structural element by screwing a first screw into the nut held in the first housing.

[0034] The guiding part of the passage formed through the second part of the connecting element may have a dimension along a third direction perpendicular to the first direction and the second direction which is less than a dimension of the first retaining part of the retaining member along the third direction.

[0035] The passage formed through the second part of the connecting element may include an insertion portion adapted for inserting the first retention portion of the retaining member through the passage. The insertion portion may be located at one end of the guide portion of the passage in the first direction.

[0036] The first structural element may include a third hole, the cylindrical portion of the retaining member passing through the third hole formed through the first structural element, the retaining member comprising a second retaining portion in a second direction along the first axis connected to a second end of the cylindrical portion, the second retention part comprising a bearing face supported along the direction of the first axis on an external face of the first structural element. The first structural element may include a recess around the third hole, such that the outer face of the first structural element forms a shoulder against which the bearing face of the second retention component makes contact. The second retention component may be entirely housed within the recess. The third structural element may cover an area of ​​the outer face of the first structural element where the recess is formed.

[0037] In another aspect, a turbomachine ejection cone is proposed, comprising an assembly as described above. In another aspect, a turbomachine comprising an ejection cone as described above is proposed.

[0038] From another perspective, a method for assembling the whole is proposed as described above, the method comprising: - apply the nut device support to the inner face of the first structural element so that the nut retained in the first housing and the nut retained in the second housing are respectively aligned with the first hole and the second hole formed through the first structural element; - attach the nut device support to the first structural element.

[0039] The method may include applying the second structural element to the outer face of the first structural element so that the hole formed through the second structural element is aligned with the first hole formed through the first structural element.

[0040] The attachment of the nut device support to the first structural element may include: - insert the first screw through the hole formed through the second structural element and the first hole formed through the first structural element; - screw the first screw into the nut held in the first housing of the nut device support.

[0041] In particular, the first screw can be screwed into the nut of the first housing with the nut located on the side of the first deformable part of the connecting element. The first screw can be screwed into the nut of the first housing while the nut is accessible. The load transfer to the nut of the first housing during the screwing of the first screw into the nut of the first housing can be achieved by maintaining manually lock the nut into position. In other words, the first nut can be manually prevented from rotating while tightening the first screw.

[0042] The method may include inserting the retaining member into the third hole formed through the first structural element so that the bearing face of the second retaining part is supported along the direction of the first axis on the external face of the first structural element.

[0043] The application of the nut device support to the inner face of the first structural element may include: - Insert the first retention part of the retaining element into the insertion part of the passage formed through the second part of the connecting element, - move the support relative to the first structural element in the first direction so as to move the cylindrical portion of the retaining member in the first direction in the guide part of the passage formed through the second part of the connecting element and place the bearing face of the first retaining part in contact with the face of the second part of the connecting element which is opposite to the first structural element.

[0044] The method may include applying the third structural element to the outer face of the first structural element so that the hole formed through the third structural element is aligned with the second hole formed through the first structural element.

[0045] The process may include: - insert the second screw through the hole formed through the third structural element and the second hole formed through the first structural element; - screw the second screw into the nut held in the second housing of the nut device support.

[0046] In particular, the second screw can be screwed into the nut of the second housing with the latter located on the side of the second part 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. The second screw can be screwed into the nut of the second housing "blind," i.e., without access to the nut of the second housing. The forces absorbed in the nut of the second housing during the tightening of the second screw can be supported by the edges (i.e., the walls) of the guide portion of the passage formed through the second part of the connecting element, which abuts in the third direction against the cylindrical portion of the retaining member. In other In terms of terms, it is not necessary to intervene manually to block rotation of the nut in the second housing when screwing in the second screw. Brief description of the drawings

[0047] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which:

[0048] Figure 1 is a partial schematic half-view in axial section of a prior art turbomachine;

[0049] Figure 2 is a schematic perspective view of an ejection cone of the turbomachine in Figure 1;

[0050] Figure 3 includes figures 3a and 3b, each of which is a schematic perspective view of an ejection cone according to the present description;

[0051] Figure 4 is a perspective view of an assembly illustrating a first structural element, a second structural element and a third structural element fixed together by means of a nut device implemented in the ejection cone of Figure 3;

[0052] Figure 5 is a perspective view of the nut device in Figure 4;

[0053] Figure 6 includes Figure 6a showing a perspective view of part of the nut device of Figure 4 which includes a retaining member and Figure 6b showing the retaining member of Figure 6a;

[0054] Figure 7 includes figures 7a and 7b, each of which is a schematic cross-sectional view illustrating the assembly of figure 4 respectively between a rest state and a dilated state;

[0055] Figure 8 includes figures 8a and 8b, each of which is a perspective view of an alternative embodiment of a nut housing for the nut device of figure 5;

[0056] Figure 9 includes figures 9a to 9e which schematically represent an assembly process for the whole of figure 4. Description of the implementation methods

[0057] Reference is now made to Figure 3. Figure 3 represents a turbomachine discharge cone 40 with longitudinal axis X. In the following, orientation qualifiers such as "longitudinal," "radial," or "circumferential" are defined with reference to the longitudinal axis X. The discharge cone 40 comprises an upstream portion 40a, substantially axisymmetric about the longitudinal axis X, and a downstream portion 40b, conical about the longitudinal axis X with a cross-section decreasing downstream. The upstream portion 40a It includes an external annular acoustic wall 42, for example multi-perforated, which is intended to radially delimit a primary annular turbomachine flow channel within it. The upstream portion 40a of the ejection cone 40 further comprises an acoustic box arranged radially within the annular acoustic wall 42. The box is radially delimited internally by an internal annular wall 44, visible in Figure 3a. In the illustrated example, the annular acoustic wall 42 comprises two sectors (or "half-shells") arranged circumferentially end-to-end around the longitudinal axis X. Moreover, the internal annular wall 44 is in this case a single piece around the longitudinal axis X.

[0058] As seen in Figure 3a, the annular acoustic wall 42, the inner annular wall 44 and the downstream part 40b are assembled together by a plurality of nut devices 60. Similarly, as seen in Figure 3b, the two sectors of the annular acoustic wall 42 are connected to each other by means of a connecting piece 46 and another plurality of nut devices 60.

[0059] In the following, a nut device 60 is described in more detail with reference to figures 4 to 9.

[0060] Figure 4 represents a turbomachine assembly comprising a first structural element 51, a second structural element 52 and a third structural element 53. The assembly further includes a nut device 60 for connecting together the first structural element 51, the second structural element 52 and the third structural element 53.

[0061] The first structural element 51 comprises a first hole 54 and a second hole 55. The first hole 54 and the second hole 55 are spaced apart from each other along a first direction d1. The first structural element 51 has an internal face and an external face.

[0062] 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 from each other along 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.

[0063] The nut device 60 comprises, firstly, a support 70. The support 70 is fixed to the inner face of the first structural element 51. The support 70 comprises at least a first housing 72 and a second housing 72 connected by a connecting element 71. The first housing 72 and the second housing 72 each retain a nut 61. (visible in Figure 5) aligned respectively with the first hole 54 and the second hole 55 formed through the first structural element 51. The first housing 72 and the second housing 72 of the support 70 of the nut device 60 are therefore also spaced from each other along a first direction d1. The connecting element 71 is here a rod extending globally in the first direction d1 between the first housing 72 and the second housing 72.

[0064] Each housing 72 can be adapted to retain the respective nut 61 in a floating manner. "Floating" means that limited movement of the nut 61 within the respective housing 72 of the support 70 is permitted. Each housing 72 comprises (is formed by) a base 79 and a plurality of tabs 80 projecting from the base 79. The base 79 has a hole 81. Each nut 61 is positioned on the base 79 of the respective housing 72, aligned with the hole 81 formed through the base 79. Each nut 61 is held in place in the respective housing 72 by complementary shape between each tab 80 of the housing 72 and a relief 62 formed on the periphery of the nut 61. According to a first embodiment of the first housing 72 and the second housing 72 shown in Figures 4, 6 and 8a, each tab 80 of the housing 72 is engaged in a hollow relief 62 formed on the periphery of the nut 61. Each housing 72 comprises 3 tabs 80 in the first embodiment.According to a second embodiment of the first housing 72 and the second housing 72 shown in Figure 8b, each tab 80 has a recessed relief into which a projecting relief 62, formed at the periphery of the nut 61, is engaged. The projecting relief 62 is in this case a rib. Each housing 72 comprises two tabs 80 in the second embodiment.

[0065] The second structural element 52 is fixed to the first structural element 51 by a first screw 63 which passes through the first hole 54 formed through the first structural element 51 and the hole 57 formed through the second structural element 52. The first screw 63 is screwed into the nut 61 retained in the first recess 72 of the support 70 of the nut device 60. The support 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 retained in the first recess 72 of the support 70, which also ensures the fixing of the second structural element 52 to the first structural element 51. The first structural element 51 is therefore without specific holes for fixing the support 70 of the nut device 60 to the first structural element 51.This reduces the number of holes made in the first structural element 51, in order to limit the risks of damage to the first structural element 51.

[0066] The third structural element 53 is fixed to the first structural element 51 by a second screw 63 which passes through the second hole 55 formed through the first element of structure 51 and the hole 58 formed through the third structural element 53. The second screw 63 is screwed into the nut 61 held in the second housing 72 of the support 70 of the nut device 60.

[0067] According to a first embodiment, the second structural element 52 is one of the sectors of the annular acoustic wall 42 and the third structural element 53 is the other of the sectors of the annular acoustic wall 42. According to the first embodiment, the first structural element 51 is the connecting piece 46 linking the two sectors of the annular acoustic wall 42. In the first embodiment, the first direction d1 coincides with a circumferential direction around the longitudinal axis X.

[0068] According to a second embodiment, the first structural element 51 is the internal annular wall 44, the second structural element 52 is one of the sectors of the annular acoustic wall 42 and the third structural element 53 is the downstream part 40b of the ejection cone 40. In the second embodiment, the first direction d1 comprises a component along the longitudinal direction and a component along the circumferential direction around the longitudinal axis X.

[0069] In each of the first and second embodiments, a second direction d2 is defined perpendicular to the first direction d1. The second direction d2 coincides here with the radial direction with respect to the longitudinal axis X. Finally, a third direction d3 is also defined perpendicular to the first direction d1 and to the second direction d2.

[0070] In both 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 materials have a low density, thus allowing for a reduction in the overall mass. In contrast, the support 70 for the nut device 60 is made of a metallic material. Therefore, the first structural element 51 is made of a material whose coefficient of thermal expansion is lower than the coefficient of thermal expansion of the material in which the support 70 for the nut device 60 is made.

[0071] Thus, as shown in Figure 7a, when the turbomachine is stopped, the assembly is subjected to a first temperature, the first hole 54 and the second hole 55 formed through the first structural element 51 are spaced according to a first spacing L1 along the first direction d1. Also, the first housing 72 and the second housing 72 of the support 70 of the nut device 60 are also spaced according The first gap L1 follows the first direction d1. However, when the turbomachine is in operation, the assembly is subjected to a second temperature that is higher than the first temperature due to the circulation of hot gases within the turbomachine. As a result, 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 according to a second gap L2 along the first direction d1. The second gap L2 is greater than the first gap L1. Due to the support fixing 70 to the first structural element 51 by the links between the screws 63 and the nuts 62, the spacing along the first direction between the first housing 72 and the second housing 72 of the support 70 of the nut device 60 is constrained by the second spacing L2 along the first direction d1. However, the support 70 is subject to a greater thermal expansion, which induces mechanical stresses in each fixing between one of the nuts 62 and the corresponding screw 63 and then in the first structural element 51.

[0072] To overcome this, the connecting element 71 includes a first portion 73 adapted to compensate for the thermal expansion of the support 70, which is greater than the thermal expansion of the first structural element 51. Thus, the alignment between each nut 61 and the respective hole 54, 55 formed through the first structural element 51 is maintained during the operation of the turbomachine, particularly when the first structural element 51 and the nut assembly 60 are subjected to high temperatures. Furthermore, the stresses exerted on the first structural element 51 due to the greater thermal expansion of the support 70 of the nut assembly 60 are reduced. Consequently, the risk of damage to the first structural element 51 is reduced or even eliminated.

[0073] To do this, with reference to Figure 7, the first part 73 of the connecting element 71 is elastically deformable to compensate for the greater thermal expansion of the support 70. The first part 73 of the connecting element is deformable between: - a rest state (Figure 7a) in which the bonding element 71 is subjected to the first temperature and in which the first part 73 of the bonding element 71 has a conformation having a first dimension D1 along the second direction d2, and - a dilated state (figure 7b) in which the bonding element 71 is subjected to the second temperature which is higher than the first temperature and in which the first part 73 of the bonding element 71 has a conformation having a second dimension D2 along the second direction d2.

[0074] As can be seen in Figure 7, the second dimension D2 of the first part 73 of the connecting element 71 in the dilated state is greater than the first dimension D1 of the first part 73 of the connecting element 71 in the rest state.

[0075] In particular, the conformation of the first portion 73 of the connecting element 71 in both the rest and expanded states is a deflection along the second direction d2. The maximum deflection formed by the bending of the first portion 73 of the connecting element 71 in the rest state may be less than the maximum deflection formed by the bending of the first portion 73 of the connecting element 71 in the expanded state. The connecting element may have a suitable thickness to facilitate its deformation along the second direction d2. The thickness of the connecting element may be less than or equal to 2 mm.

[0076] A clearance is also provided along the first direction d1 between the second structural element 52 and the third structural element 53. This prevents the second structural element 52 and the third structural element 53 from bearing against each other along the first direction d1 and exerting mechanical stresses on each other when they thermally expand during the operation of the turbomachine, which could damage them.

[0077] Furthermore, the connecting element 71 of the support 70 comprises a second portion 74 that is less deformable than the first portion 73. Remarkably, the second portion 74 of the connecting element 71 is closer to the second housing 72 than is the first portion 73 of the connecting element 71. The second portion 74 of the connecting element 71 is particularly visible in Figure 6a. The second portion 74 is applied against the inner face of the first structural element 51. The second portion 74 includes a passage 75. The passage 75 includes a guide portion 76 extending along 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 light extending along the first direction d1.

[0078] The assembly further includes a retaining member 90, which is particularly visible in Figures 6a and 6b. The retaining member 90 is fixed relative to the first structural element 51. The retaining member 90 comprises a cylindrical portion 91 along a first axis A1 that projects from the inner face of the first structural element 51. 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 through the second portion 74 of the connecting element 71. Rotation of the support 70 of the nut device 60 relative to the first structural element 51 is thus prevented, firstly, when the support 70 is fixed to the first structural element 51 by tightening the first screw 63 into the retained nut 61. in the first housing 72 and especially on the other hand during the fixing of the third structural element 53 to the first structural element 51 by screwing the second screw 63 into the nut 61 retained in the second housing 72. Also, the guide part 76 of the passage 75 formed through the second part 74 of the connecting element 71 allows the movement of the cylindrical portion 91 of the retaining member 90 in the first direction in the passage 75 when the support 70 expands thermally more than the first structural element 51 during the operation of the turbomachine.

[0079] The retaining member 90 also includes a first retaining portion 92 in a first direction S1 along the first axis A1, which is connected to a first end of the cylindrical portion 91. The first retaining portion 92 has a bearing face along the direction of the first axis A1 against a face of the second portion 74 of the connecting element 71 that is opposite the first structural element 51. This allows the second portion 74 of the connecting element 71 to be held against the inner face of the first structural element 51. The retaining member 90 maintains the alignment between the nut 61 retained in the second recess 72 of the support 70 and the second hole 55 formed through the first structural element 51, particularly after the support 70 is fixed to the first structural element 51 by screwing the first screw 63 into the nut 61 retained in the first recess 72.

[0080] The guiding part 76 of the passage 75 formed through the second part 74 of the connecting element 71 has a dimension along the third direction d3 which is less than a dimension of the first retaining part 92 of the retaining member 90 along the third direction d3. This prevents the first retaining part 92 of the retaining member 90 from being withdrawn by the guiding part 76 of the passage 75 in the first direction S1 of the direction of the first axis A1.

[0081] The passage 75 formed through the second part 74 of the connecting element 71 includes an insertion part 77 adapted to insert the first retention part 92 of the retaining member 90 through the passage 75 formed through the connecting element 71. The insertion part 77 is located at one end of the guiding part 76 of the passage 75 along the first direction d1.

[0082] The cylindrical portion 91 of the retaining member 90 also passes through a third hole 56 formed through the first structural element 51. The retaining member 90 includes a second retention part 93 in a second direction S2 along the first axis A1 which is connected to a second end of the cylindrical portion 91. The second retention part 93 includes a bearing face bearing along the direction of the first axis A1 on the external face of the first structural element 51.

[0083] The first structural element 51 includes, in particular, a recess around the third hole 56, such that the outer face of the first structural element 51 forms a shoulder against which the bearing face of the second retention portion 93 is in contact. The second retention portion 93 is then entirely received within the recess. The third structural element 53 can thus cover an area of ​​the outer face of the first structural element 51 where the recess is formed.

[0084] Reference is now made more specifically to figure 9 which schematically represents a method of assembling the assembly for a turbomachine as described above.

[0085] The process includes a first step visible in Figure 9a. The first step includes the application of the second structural element 52 to the external face of the first structural element 51 so that the hole 57 formed through the second structural element 52 is aligned with the first hole 54 formed through the first structural element 51.

[0086] The method includes a second step visible in Figure 9b. The second step includes the insertion of the retaining member 90 into the third hole 56 formed through the first structural element 51 so that the bearing face of the second retaining part 93 is in contact along the direction of the first axis A1 with the external face of the first structural element 51. The second retaining part 93 is in particular entirely housed in the recess of the first structural element 51.

[0087] The method includes a third step visible in Figures 9c and 9d. The third step includes the application of the support 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 housing 72 and the nut 61 retained in the second housing 72 are respectively aligned with the first hole 54 and the second hole 55 formed through the first structural element 51.

[0088] To achieve this, the application of the support 70 of the nut device 60 onto the inner face of the first structural element 51 comprises: - the insertion of the first retention part 92 of the retaining member 90 into the insertion part 77 of the passage 75 formed through the second part 74 of the connecting element 71, - the displacement of the support 70 relative to the first structural element 51 along the first direction d1 as represented by the arrow F.

[0089] This allows the cylindrical portion 91 of the retaining member 90 to be moved along the first direction in the guide part 76 of the passage 75 formed through the second part 74 of the connecting element 71 and to position the bearing face of the first part of retention 92 in support on the face of the second part 74 of the connecting element 71 which is opposite to the first structural element 51.

[0090] The process includes a fourth step visible in Figure 9d. The fourth step includes attaching the support 70 of the nut device 60 to the first structural element 51.

[0091] The attachment of the support 70 of the nut device 60 to the first structural element 51 may include: - the insertion of 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; - screwing the first screw 63 into the nut 61 held in the first housing 72 of the support 70 of the nut device 60.

[0092] The process includes a fifth step, shown in Figure 9e. The fifth step comprises: - the application of the third structural element 53 onto the external face of the first structural element 51 such 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 - the insertion of 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; - the "blind" screwing of the second screw 63 into the nut 61 held in the second housing 72 of the support 70 of the nut device 60.

[0093] The retaining element 90 here fulfills an anti-rotation function of the nut 61 of the second housing 72 when screwing in the second screw 63.

Claims

Demands

1. Assembly for a longitudinal axis (X) turbomachine, the assembly comprising a first structural element (51) and a nut device (60), the first structural element (51) comprising a first hole (54) and a second hole (55), the nut device (60) comprising a support (70) fixed to an internal face of the first structural element (51), the support (70) comprising at least a first housing (72) and a second housing (72) connected to each other by a connecting element (71), the first housing (72) and the second housing (72) each retaining a nut (61) aligned respectively with the first hole (54) and the second hole (55) formed through the first structural element (51), the connecting element (71) being, in whole or in part, adapted to compensate for a thermal expansion of the support (70) greater than a thermal expansion of the first structural element (51).

2. Assembly according to the preceding claim, wherein the first housing (72) and the second housing (72) of the support (70) of the nut device (60) are spaced apart from each other in a first direction (d1), the connecting element (71) being, in whole or in part, deformable to compensate for the upper thermal expansion of the support (70) between: - a rest state in which the connecting element (71) is subjected to a first temperature and in which the connecting element (71) has a conformation having a first dimension (D1) along a second direction (d2) perpendicular to the first direction (d1), and - a dilated state in which the bonding element (71) is subjected to a second temperature which is greater than the first temperature and in which the bonding element (71) has a conformation having a second dimension (D2) along the second direction (d2), the second dimension (D2) being different from the first dimension (D1).

3. Assembly according to claim 2, wherein the conformation of the connecting element (71) in the rest state is a bend along the second direction (d2) and / or the conformation of the connecting element (71) in the dilated state is a bend along the second direction (d2).

4. A claim according to any one of the preceding claims, wherein the first structural element (51) is made of a material whose coefficient of thermal expansion is less than the coefficient of thermal expansion of a material in which the support (70) of the nut device (60) is made.

5. Assembly according to any one of the preceding claims, the assembly comprising a second structural element (52) applied to a face external to the first structural element (51), the second structural element (52) comprising a hole (57) aligned with the 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) which passes through the first hole (54) formed through the first structural element (51) and the hole (57) formed through the second structural element (52), the first screw (63) being screwed into the nut (61) retained in the first housing (72) of the support (70) of the nut device (60).

6. Assembly according to the preceding claim, the assembly comprising a third structural element (53) applied to an external face of the first structural element (51), the third structural element (53) comprising a hole (58) aligned with the 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) which passes through the second hole (55) formed through the first structural element (51) and the hole (58) formed through the third structural element (53), the second screw (63) being screwed into the nut (61) retained in the second housing (72) of the support (70) of the nut device (60).

7. An assembly according to any one of claims 2 to 6, wherein the connecting element (71) of the support (70) comprises a first portion (73) that is deformable between the rest state and the expanded state, and a second portion (74) that is less deformable 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) having a passage (75) that includes a guide portion (76) extending along the first direction (d1), the assembly further comprising a retaining member (90) that is fixed relative to the first structural element (51), the retaining member (90) comprising a cylindrical portion (91) about a first axis (A1) that projects from the inner face of the first structural element (51), the cylindrical portion (91) passing through the guide portion (76) of the passage (75) formed through the second part (74) of the connecting element (71).

8. Assembly according to the preceding claim, wherein the retaining member (90) comprises a first retaining part (92) in a first direction (S1) along the first axis (A1) connected to a first end of the cylindrical portion (91), the first retaining part (92) having a bearing face bearing along the direction of the first axis (A1) on a face of the second part (74) of the connecting element (71) which is opposite the first structural element (51).

9. Assembly according to claim 7 or 8, wherein the first structural element (51) comprises a third hole (56), the cylindrical portion (91) of the organ of retention (90) passing through the third hole (56) formed through the first structural element (51), the retention member (90) comprising a second retention part (93) in a second direction (S2) along the first axis (A1) connected to a second end of the cylindrical portion (91), the second retention part (93) comprising a bearing face bearing along the direction of the first axis (A1) on an external face of the first structural element (51).

10. A method for assembling the assembly according to any one of the preceding claims, the method comprising: - apply the support (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 housing (72) and the nut (61) retained in the second housing (72) are respectively aligned with the first hole (54) and the second hole (55) formed through the first structural element (51); - fix the support (70) of the nut device (60) to the first structural element (51).

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