ACOUSTIC SEALING ELEMENT

Description

Technical Field

[0001] The present invention relates to the general field of acoustic attenuation structures. It relates more particularly to acoustic panels used in aircraft engines as well as in gas turbines and other turbomachines, in particular to reduce noise generated by the fan or by the ejection of gases at the exhaust. Prior art

[0002] There figure 1is an illustration of a propulsion assembly 7 extending along a longitudinal axis A comprising a short nacelle 70 and a turbojet 700. The turbomachine comprises in particular a compressor 77, a combustion chamber 78 and a turbine 79. The nacelle 70 has a structure comprising an upstream section forming an air inlet 72, a middle section 73 and a downstream section 74 comprising a thrust reverser. The middle section 73 comprises fan cowls intended to surround a fan 710 of the turbojet 700. The downstream section 74 is intended to surround the combustion chamber 78 of the turbojet and an ejection nozzle 720.

[0003] Acoustic panels 81 may be arranged on the inner face of the air inlet 72 located opposite the fan 710 to reduce the noise generated by said fan 710. Acoustic panels 82 may be arranged on the inner face of the downstream section 74, at the level of the thrust reversers, or on the outer face of the turbojet 700 which comprises the combustion chamber 78. In addition, acoustic panels 83 may be arranged at the level of the nozzle 720, to reduce the noise generated by the ejection of gases at the exhaust.

[0004] Acoustic panels are typically made up of an acoustic surface plate or skin permeable to the acoustic waves that are to be attenuated and a reflective solid plate or skin called a "closing plate", a cellular body being arranged between these two walls. The cellular body is generally made up of a set of partitions, for example in the shape of a honeycomb. As is well known, such structures form Helmholtz-type resonators that make it possible to attenuate the acoustic waves in a certain frequency range. Acoustic panels of this type are described in particular in documents US 5,912,442 and GB 2,314,526.

[0005] Acoustic panels may have through openings or cavities, allowing access to elements located behind the panel. For example, an acoustic panel may be placed close to the surface of a structure that includes fixing screws, which require regular access.

[0006] These openings or through cavities cause a significant reduction in the acoustic treatment achieved by the acoustic panel. On the one hand, the presence of an opening or through cavity reduces the performance of the acoustic panel by reducing the functional surface area of ​​said panel. On the other hand, the opening or through cavity causes discontinuities in the acoustic treatment, called "splices", which will modify the structure of the acoustic field by repelling the energy propagating in the acoustic panel. Thus, the reduction in acoustic performance is much greater than the reduction in performance due solely to the loss of acoustic functional surface area.

[0007] Furthermore, such openings or cavities in the acoustic panel can lead to sealing problems of the acoustic panel.

[0008] Document EP 3 779 961 describes an acoustic panel comprising a plate of absorbent material arranged between a resistive skin and a rear skin, the plate being provided with a plurality of housings in which acoustic elements are fixed. Statement of the invention

[0009] The main aim of the present invention is therefore to remedy the aforementioned drawbacks.

[0010] According to the invention, this object is achieved by means of an acoustic assembly comprising a multicellular acoustic panel having at least one through cavity in a direction X, characterized in that the acoustic assembly further comprises at least one closure element comprising a body containing one or more acoustic cells, the body being able to be inserted into the cavity and extending in the direction X between a first face and a second face, the closure element further comprising a seal on the second face of the body capable of ensuring sealing with the acoustic panel. The seal is also capable of ensuring the retention of the closure element in the acoustic panel.

[0011] Thus, the use of a sealing element with acoustic attenuation properties makes it possible to minimize the impact of the through cavity(ies) on the acoustic performance of the assembly. Indeed, the sealing element greatly reduces the loss of acoustic functional surface and does not cause significant irregularities in the structure of the overall acoustic field. The seal ensures that the sealing element is held in the acoustic panel, also ensuring the acoustic panel is watertight.

[0012] The blanking element can be easily removed if necessary to access structures or fixing systems located behind the acoustic panel, and can then be replaced.

[0013] According to a particular characteristic of the invention, the body of the sealing element takes the shape of the cavity when it is inserted into said cavity.

[0014] According to a particular characteristic of the invention, the seal of the closure element is deformable between a rest or sealing position, in which the seal extends beyond the periphery of the body perpendicular to the direction X, and a mounting or dismounting position, in which the seal does not extend beyond the periphery of the body perpendicular to the direction X.

[0015] According to another particular characteristic of the invention, the sealing element further comprises a passage extending from the seal and opening onto the first face of the body, configured to allow the insertion of an object capable of deforming the seal from its rest position to its assembly or disassembly position.

[0016] According to another particular characteristic of the invention, the passage comprises at least one threaded portion.

[0017] The threaded passage of the sealing element, in combination with the thread of the inserted object, makes it easier to maintain the seal in its assembly or disassembly position during handling of the sealing element. In addition, the threaded passage and the thread of the inserted object can facilitate the assembly and disassembly of the sealing element, for example by allowing the use of a screw extractor.

[0018] According to another particular characteristic of the invention, each cell of the acoustic panel and each cell of the sealing element comprises a hollow acoustic element having a shape gradually narrowing between a base and a top.

[0019] According to another particular characteristic of the invention, the acoustic impedance of the acoustic cell(s) of the sealing element has a value between 90% and 110% of the value of the acoustic impedance of the cells of the acoustic panel.

[0020] According to another particular characteristic of the invention, the closure element has axial symmetry.

[0021] The axial symmetry may be along the X axis which intersects the first surface and the second surface of the body of the closure element at their center.

[0022] The invention further relates to a method for mounting an acoustic assembly in accordance with the invention, comprising placing at least one sealing element in at least one through cavity of the multicellular acoustic panel, said sealing element occupying the volume defined by the cavity so that the first face of the body of the sealing element is located in the extension of a first face of the acoustic panel and the seal of the sealing element provides a seal between the second face of the body of the sealing element and a second face of the acoustic panel opposite the first face of the panel.

[0023] According to a particular characteristic of the invention, the placement of the sealing element comprises the following steps: inserting an object inside the passage to deform the seal from its rest or sealing position to its assembly or disassembly position, placing the sealing element in the cavity of the multicellular acoustic panel while maintaining the sealing seal in its assembly or disassembly position, said sealing element occupying the volume defined by the cavity so that the first face of the body of the sealing element is located in the extension of a first face of the acoustic panel, removing the object inserted into the passage to allow the seal to return to its rest or sealing position, so that the seal provides sealing between the second face of the body of the sealing element and a second face of the acoustic panel opposite the first face.

[0024] The invention further relates to a method for dismantling an acoustic assembly in accordance with the invention, comprising removing at least one sealing element from a through cavity of the multicellular acoustic panel by deforming the seal of said sealing element.

[0025] According to a particular characteristic of the invention, the removal of the sealing element comprises the following steps: inserting an object inside the passage to deform the seal from its resting or sealing position to its mounting or dismounting position, removing the sealing element from the cavity of the multicellular acoustic panel while maintaining the sealing gasket in its mounting or dismounting position.

[0026] The invention further relates to a method of repairing a multi-cellular acoustic panel comprising a damaged area, comprising the following steps: the production of at least one through cavity in a direction X by removing the cells present at least in part in the damaged area, the provision of at least one sealing element comprising a body containing one or more acoustic cells, the body conforming to the shape of the cavity and extending in the direction X between a first face and a second face, the sealing element further comprising a seal on the second face, the placement of said sealing element in the through cavity, the sealing element occupying the volume defined by the cavity so that the first face of the body of the sealing element is located in the extension of a first face of the acoustic panel and the seal of the sealing element provides a seal between the second face of the body of the sealing element and a second face of the acoustic panel opposite the first face.

[0027] According to a particular characteristic of the invention, the seal of the closure element is deformable between a rest or sealing position, in which the seal extends beyond the periphery of the body perpendicular to the direction X, and a mounting or dismounting position, in which the seal does not extend beyond the periphery of the body perpendicular to the direction X, and in which the closure element further comprises a passage extending from the seal and opening onto the first face of the body, the placement of the closure element comprising the following steps: inserting an object inside the passage to deform the seal from its rest or sealing position to its assembly or disassembly position, placing the sealing element in the cavity of the multicellular acoustic panel while maintaining the seal in its assembly or disassembly position, said sealing element occupying the volume defined by the cavity so that the first face of the body of the sealing element is located in the extension of a first face of the acoustic panel, removing the object inserted into the passage to allow the seal to return to its rest or sealing position, so that the seal provides sealing between the second face of the body of the sealing element and a second face of the acoustic panel opposite the first face.

[0028] Finally, the invention relates to a sealing element comprising a body extending in a direction X between a first face and a second face and containing one or more acoustic cells, the first face comprising one or more acoustic skins, said sealing element further comprising a sealing cavity delimited at least by the second face of the body and by a deformable seal.

[0029] According to a particular characteristic of the invention, the seal is deformable between a rest or sealing position, in which the seal extends beyond the periphery of the body perpendicular to the direction X, and a mounting or dismounting position, in which the seal does not extend beyond the periphery of the body perpendicular to the direction X.

[0030] According to another particular characteristic of the invention, the sealing element further comprises a passage extending from the sealing cavity and opening onto the first face of the body, configured to allow the insertion of an object capable of deforming the seal from its rest position to its assembly or disassembly position.

[0031] According to another particular characteristic of the invention, the sealing element further comprises a rigid plate extending perpendicular to the direction X so that the sealing cavity is delimited by the second face of the body, by the deformable seal and by the rigid plate, the deformable seal connecting the edges of the rigid plate to the second face of the body. Brief description of the drawings

[0032] [ Fig. 1 ] There figure 1 is a schematic sectional view illustrating a prior art propulsion assembly comprising acoustic panels. Fig. 2 ] There figure 2is a sectional view illustrating an acoustic assembly according to the invention arranged against a structure in exploded view. Fig. 3 ] There figure 3 is a 3D sectional view illustrating a sealing element when the seal is in the sealing position, the sealing element being inserted into an acoustic panel in accordance with the invention. Fig. 4 ] There figure 4 is a 3D sectional view illustrating the shutter element of the figure 3 when the seal is in the mounting or dismounting position, the sealing element being inserted into an acoustic panel. Fig. 5 ] There Figure 5 is a 3D sectional view illustrating the sealing element of the figures 3 And 4 when the seal is in the mounting or dismounting position, the sealing element being removed from an acoustic panel. Fig. 6 ] There figure 6 is a 3D sectional view illustrating the sealing element of the figures 3 , 4 And 5when the seal is in the rest position, the sealing element being removed from an acoustic panel. Fig. 7 ] There figure 7 is a sectional view of an acoustic panel showing a damaged area. [Fig. 8] There figure 8 is a sectional view of an acoustic assembly in accordance with the invention, which comprises the acoustic panel of the figure 6 in which the damaged area has been removed and a sealing element. Fig. 9 ] There figure 9 is a sectional view of a sealing element comprising three acoustic cells aligned in accordance with the invention. Fig. 10 ] There figure 10 is a sectional view of a sealing element comprising three acoustic cells placed in a “triangle” in accordance with the invention. Fig. 11 ] There figure 11 is a 3D sectional view of a sealing element comprising a single acoustic cell in accordance with the invention. Description of the embodiments

[0033] There figure 2illustrates an acoustic assembly 1 disposed against a structure 10, the acoustic assembly 1 comprising an acoustic panel 100 and one or more sealing elements 200.

[0034] In particular, the figure 2 illustrates an acoustic panel 100 comprising a plurality of acoustic cells 110 extending in a direction X between a first face 100a of the acoustic panel 100 and a second face 100b of the acoustic panel 100 opposite the first face 100a.

[0035] The acoustic panel 100 comprises a plurality of partitions 111 extending between the first face 100a and the second face 110b of the acoustic panel, the partitions forming a network of ribs delimiting the acoustic cells 110. The height of the acoustic cells 110 is chosen so as to obtain processing of interesting frequencies according to the use which will be made of the acoustic panel 100.

[0036] In the example shown on the figure 2, the cells 110 of the acoustic panel 100 have a round section. It is of course not outside the scope of the invention if the cells of the acoustic panel have a square, rectangular, hexagonal or other section, for example a so-called “honeycomb” structure.

[0037] In the example described here, each acoustic cell 110 of the acoustic panel 100 has at least one complex hollow acoustic element 112 having a shape that gradually narrows between a base 112a and a top 112b. It is of course not outside the scope of the invention if only some of the acoustic cells of the acoustic panel have such an acoustic element, or if none of the acoustic cells of the acoustic panel have such an acoustic element. Each acoustic cell that does not have a hollow acoustic element can be made up solely of the partitions that delimit it.

[0038] In the example shown on the figure 2, the hollow acoustic elements 112 of the acoustic panel 100 have a pyramidal shape. However, it does not depart from the scope of the invention if the hollow acoustic elements of the acoustic panel have, for example, a conical, spiral or funnel shape. In the example shown in the figure 2 , the hollow acoustic elements 112 of the acoustic panel 100 have a symmetry of revolution. However, it does not go beyond the scope of the invention if the hollow acoustic elements are asymmetrical.

[0039] Preferably, the hollow acoustic elements 112 of the acoustic panel 100 have a thickness of less than 1 mm, for example between 0.3 mm and 0.5 mm. Preferably, the base 112a of the hollow acoustic elements 112 is included in a circle whose diameter is between 5 mm and 50 mm. For example, the base 112a of the hollow acoustic elements 112 is included in a circle with a diameter of 32 mm. Preferably, the height H 110 of the acoustic cells 110 is between 5 mm and 100 mm. For example, the height H 110 of the acoustic cells 110 is 65 mm.

[0040] The first face 100a of the acoustic panel 100 is covered by an upper acoustic skin 101. The upper acoustic skin 101 has the function of allowing the sound waves to be attenuated to pass inside the acoustic panel 100. For this purpose, the acoustic skin 101 comprises a plurality of perforations 101a in the example described in the figure 2The acoustic skin 101 may be made of composite material, for example based on carbon fibers.

[0041] The acoustic panel 100 can be produced in a well-known manner from polymer, composite or metallic material, by additive manufacturing or by conventional means.

[0042] In the example shown on the figure 2 , the direction X in which the acoustic cells 110 extend is perpendicular to the first face 100a and to the second face 100b of the acoustic panel 100. It is of course not outside the scope of the invention if the direction in which the acoustic cells are directed is inclined, that is to say is not perpendicular to the first face or to the second face of the acoustic panel.

[0043] The second face 100b of the acoustic panel 100 may be covered by a closing skin, intended to reflect the sound waves entering the cells 110 of the acoustic panel 100, particularly in the case where the second face 100b of the acoustic panel 100 is not arranged against a structure.

[0044] The second face 100b of the acoustic panel 100 may be disposed against or near the surface 10b of a structure 10, for example an aircraft engine, an air intake or an inverter, as in the example described in the figure 2 The acoustic panel 100 may correspond to one of the panels 81, 82 or 83 described in connection with the figure 1. It is of course not outside the scope of the invention if the acoustic panel is used for a structure which is not an aircraft engine, or even which is not a turbomachine. Thus, the second face 100b of the acoustic panel 100 preferably matches the shape of the surface 10b of the structure 10, which may not be flat. The structure 10 may include portions or elements on its surface 10b to which it is necessary to have access, for example fixing screws 11.

[0045] For this purpose, one or more through cavities 120 oriented in the direction X are present in the acoustic panel 100, the through cavities 120 extending between the first face 100a and the second face 100b of the acoustic panel 100. Preferably, these through cavities 120 are placed so as to allow access to portions or elements on the surface 10b of the structure 10, for example to the fixing screws 11 as illustrated in the figure 2. Preferably, the walls of the through cavities 120 correspond to the outer partitions of acoustic cells 110 of the acoustic panel 100, that is to say that none of the acoustic cells 110 or partitions 111 of the acoustic panel 100 is “cut” or truncated by a through cavity 120. Thus, preferably, the cavity(ies) 120 extend in the same direction as the acoustic cells 110 of the acoustic panel 100.

[0046] Acoustic set 1 shown on the figures 2 to 6 comprises, in addition to the acoustic panel 100, one or more closure elements 200. The number of closure elements 200 may be equal to the number of through cavities 120 of the acoustic panel 100. In order to simplify the figures and improve their readability, the acoustic cells 110 of the acoustic panel 100 are not shown in the figures 3 to 6 .

[0047] Each closure element 200 comprises a body 220, the shape of which matches the shape of the through cavity 120 in which it is configured to be inserted. The body 220 may be made of thermoplastic material, for example by additive manufacturing or thermoplastic injection. It is of course not outside the scope of the invention if the external shape of the body is not complementary to the through cavity, provided that the insertion of the body into said cavity is permitted by the external geometry of the body and by the internal geometry of the cavity.

[0048] The body 220 of the closure element 200 contains two acoustic cells 210 extending in the direction X between a first face 220a of the body 220 and a second face 220b of the body 220 opposite the first face 220a. The acoustic cells 210 are delimited by partitions 211 extending between the first face 220a and the second face 220b of the body 220.

[0049] In the example presented on the figures 2 to 6 , the cells 210 of the closure element 200 have a round section. It is of course not outside the scope of the invention if the cells of the closure element have a square, rectangular, hexagonal or other section, for example a so-called “honeycomb” structure. Preferably, the acoustic cells 210 of the closure element 200 have a geometry identical to that of the acoustic cells 110 of the acoustic panel 100.

[0050] In the example described here, each acoustic cell 210 of the closure element 200 has at least one complex hollow acoustic element 212 having a shape that gradually narrows between a base 212a and a top 212b. It is of course not outside the scope of the invention if only some of the acoustic cells of the closure element have such an acoustic element, or if none of the acoustic cells of the closure element have such an acoustic element. Preferably, if the acoustic panel 100 has hollow acoustic elements 112, the closure element 200 also has hollow acoustic elements 212.

[0051] In the example presented on the figures 2 to 6, the hollow acoustic elements 212 of the sealing element 200 have a pyramidal shape. However, it does not go beyond the scope of the invention if the hollow acoustic elements have, for example, a conical, spiral or funnel shape. In the example shown in the figures 2 to 6 , the hollow acoustic elements 112 of the closure element 200 have a symmetry of revolution. However, it does not depart from the scope of the invention if the hollow acoustic elements are asymmetrical. Preferably, the hollow acoustic elements 212 of the closure element 200 have a geometry identical to that of the hollow acoustic elements 112 of the acoustic panel 100.

[0052] Preferably, the hollow acoustic elements 212 of the sealing element 200 have a thickness of less than 1 mm, for example between 0.3 mm and 0.5 mm. Preferably, the base 212a of the hollow acoustic elements 212 is included in a circle whose diameter is between 5 mm and 50 mm. For example, the base 212a of the hollow acoustic elements 112 is included in a circle with a diameter of 32 mm. Preferably, the height H 210 of the acoustic cells 210 is between 5 mm and 100 mm. For example, the height H 210 of the acoustic cells 210 is 60 mm.

[0053] Preferably, the value of the impedance of the acoustic cells 210 of the closure element 200 is identical to or close to the value of the impedance of the acoustic cells 110 of the acoustic panel 100. In particular, the acoustic impedance of the acoustic cells 210 of the closure element 200 has a value between 90% and 110% of the value of the acoustic impedance of the cells 110 of the acoustic panel 100. Consequently, the height and geometry of the acoustic cells 210 of the closure element 200, the presence or absence of complex hollow acoustic elements 212 in said cells 210 and, where appropriate, the characteristics of said complex hollow acoustic elements 212, are chosen so as to obtain an impedance similar to that of the cells 110 of the acoustic panel 100.For example, in the case where the acoustic panel does not have complex hollow acoustic elements, but the acoustic cells of the shutter element are lower than those of the acoustic panel, it may be interesting to add complex hollow acoustic elements in the acoustic cells of the shutter element in order to obtain a similar acoustic impedance between the cells of the acoustic panel and the cells of the shutter element.

[0054] The first face 220a of the body 220 comprises one or more upper acoustic skins 221, such that each acoustic cell 210 of the closure element 200 is covered by an upper acoustic skin 221. The upper acoustic skin 221 has the function of allowing the sound waves to be attenuated to pass inside the body 220 of the closure element 200. For this purpose, the acoustic skin 221 comprises a plurality of perforations 221a in the example described in the figures 2 to 6 The upper acoustic skin 221 may be made of a composite material, for example based on carbon fibers.

[0055] The body 220 of the closure element 200 further comprises a passage 222 extending in the direction X from the first face 220a of the body 220 to the second face 220b of the body 220. The passage 222 is preferably located in the center of the body 220, that is to say it connects the center of the first face 220a to the center of the second face 220b. The passage 222 is preferably located between the acoustic cells 210 of the closure element 200. The passage 222 may be threaded. The passage 222 may be cylindrical and may have a cross-section with a diameter of between 3 mm and 10 mm, preferably 5 mm.

[0056] The passage 222 opens onto the first face 220a of the body 220, preferably onto a portion of the first face 220a which is not covered by an upper acoustic skin 221, and onto the second face 220b of the body 220.

[0057] The closure element 200 comprises, in addition to the body 220, a sealing cavity 230 extending from the second face 220b of the body 220. The passage 222 opens into the sealing cavity 230. The sealing cavity 230 is delimited at least by the second face 220b of the body 220 and by the deformable sealing and holding seal 240. As illustrated in the figures 2 to 6 , the sealing cavity 230 is delimited by the second face 220b of the body 220, by a deformable sealing and holding joint 240 and by a rigid plate 231. The rigid plate 231 can be made of plastic.

[0058] The rigid plate 231 extends perpendicular to the direction X and at a non-zero variable distance from the second face 220b of the body 220. The area of ​​the rigid plate 231 is less than the area of ​​the second face 220b of the body 220. Preferably, the rigid plate 231 has a reduced thickness along X and extends perpendicular to X over a round or oblong surface.

[0059] The deformable seal 240 closes the sealing cavity 230 by joining the edges of the rigid plate 231 to the second face 220b of the body 220. The deformable seal 240 may form a curve between the edges of the rigid plate 231 and the second face 220b of the body 220, the radius of which may be between 5 mm and 10 mm, preferably 8 mm.

[0060] The rigid plate 231 and the seal 240 may form a single part. The rigid plate 231 may also be absent from the closure element, the deformable seal then also playing the role of the rigid plate, provided that the seal is sufficiently reinforced in its part located above the center of the second face 220b of the body 220.

[0061] The deformable seal 240 can be fixed to the second face 220b of the body 220 by means of a fixing plate 233. The fixing plate 233 is fixed to the second face 220b of the body 220 and extends perpendicular to the direction X. The area of ​​the fixing plate 233 is less than the area of ​​the second face 220b of the body 220 and the fixing plate 233 extends over the second face 220b without reaching the periphery of said second face 220b. The deformable seal 240 can thus be fixed to the second face 220b of the body 220 by being present between the second face 220b and the end of the fixing plate 233.

[0062] The fixing plate 233 comprises at its center an orifice 232 located in the extension of the passage 222 of the body 220, in order to allow the passage of an object through the fixing plate 233. The orifice 232 can be tapped. If the passage 222 is tapped, the same tapping characteristics are used for the orifice 232. The portion of the fixing plate 233 located around the orifice 232 can extend towards the interior of the cavity 230, in order to ensure better guidance of any object inserted inside the passage 222 and the orifice 232.

[0063] The mounting plate 233 can be made of plastic or metal.

[0064] If the closure element 200 does not include a fixing plate, the passage 222 of the body 220 opens directly into the sealing cavity 230.

[0065] The sealing gasket 240 is deformable between a first position, called rest or sealing, and a second position, called assembly or disassembly.

[0066] In its first position, the seal 240 extends perpendicular to the direction X beyond the periphery of the body 220. Thus, if the external lateral surface of the body 220 is virtually extended in the direction X by fictitious walls delimiting a virtual portion, the seal 240 will extend beyond this virtual portion. When the seal 240 is in its first position, the rigid plate 231 is at a reduced distance d 1 from the second face 220b of the body 220.

[0067] In its second position, the seal 240 extends perpendicular to the direction X, but not beyond the periphery of the body 220. Thus, if the external lateral surface of the body 220 is virtually extended in the direction X by fictitious walls delimiting a virtual portion, the seal 240 will extend only inside this virtual portion. When the seal 240 is in its second position, the rigid plate 231 is at a distance d 2 from the second face 220b of the body 220. When the seal 240 is in its second position, the rigid plate 231 is at a distance d 2 from the second face 220b greater than the distance d 1 in which the plate 231 is located when the seal 240 is in its first position.

[0068] The seal 240 must be made of a material allowing its deformation from the first to the second position, and vice versa, for example a silicone or fluorosilicone elastomer, reinforced or not. The seal 240 must be made of a material suitable for the temperature to which said seal will be subjected.

[0069] According to a particular embodiment of the invention, the closure element has at least one axial symmetry. In the example presented in the figures 2 to 6 , the closure element 200 has a symmetry with respect to the X axis. Thus, the closure element 200 can be inserted into the through cavities 120 in two different directions. One passes from one direction to the other by performing a rotation of 108° around the X axis.

[0070] We will now describe a method for disassembling the acoustic assembly making it possible to separate the sealing element(s) from the acoustic panel. Such a method may in particular make it possible to access elements located behind the acoustic panel. For example, removing the sealing element 200 may make it possible to access a fixing screw 11 located behind the acoustic panel 100 in accordance with the example illustrated in the figure 2 .

[0071] There figure 3illustrates the sealing element 200 inserted into a through cavity 120 of the acoustic panel 100. In this configuration, the seal 240 of the sealing element 200 is in its first position, called sealing or rest, and provides sealing between the sealing element 200 and the second face 100b of the acoustic panel 100. The first face 220a of the body 220 of the sealing element 200 is located in the extension of the first face 100a of the acoustic panel 100. Thus, in this configuration, the sealing element 200 provides sealing with the second face 100b of the acoustic panel 100 and allows acoustic attenuation of all the sound waves directed towards the relatively uniform first face of the assembled acoustic assembly 1, which comprises the first face 100a of the acoustic panel 100 and the first face 220a of the body 220 of the closure element 200.Consequently, the sealing element 200 ensures good acoustic performance of the assembled acoustic assembly 1 despite the through cavities 120 present in the acoustic panel 100.

[0072] To remove the sealing element(s) 200, an object 5 is inserted inside the passage 222 of the body 220 and, if a fixing plate 233 is present in the sealing cavity 230, inside the orifice 232 of the fixing plate 233, as illustrated in the figure 4 The object 5 is inserted from the first face 220a of the body 220 of the sealing element 200 to the interior of the sealing cavity 230.

[0073] The inserted object 5 pushes against the rigid plate 231, to increase the distance between the rigid plate 231 and the second face 220b of the body 220. If the closure element does not include a rigid plate 231, the inserted object can push directly on the seal 240, provided that the latter is sufficiently strong.

[0074] Under the action of the inserted object 5, the deformable joint 240 gradually stretches between the rigid plate 231 and the second face 220b of the body 220 until it reaches its second position, called assembly or disassembly, illustrated in the figure 4. Thus, the deformable seal 240 no longer provides sealing with the second face 220b of the body 220 and no longer extends beyond the periphery of the second face 220b. In this second position, the deformable seal 240 is able to pass through the acoustic panel 100, that is to say to pass inside the through cavity 120 in which the closing element 200 is inserted.

[0075] The inserted object 5 may be a rigid rod, which may be threaded at least in part. The object 5 may be a screw. Preferably, the thread of the object 5 is adapted to the tapping of the passage 222 of the body 220 and of the orifice 232 of the fixing plate 233 if the latter are tapped. The object 5 must have a sufficient length to allow the deformation of the seal from its first position to its second position. Thus, the object 5 may have a length of value between 150% and 250% of the length of the body 220 of the closure element 200 in the X direction. The object 5 may comprise a volume at its end opposite the end which is inserted into the closure element 200, to facilitate its handling.

[0076] When the sealing gasket 240 is deformed into its second position, called the mounting or dismounting position, the sealing element 200 can be removed from the acoustic panel 100. To avoid damaging the gasket 240, the pressure of the object 5 on the rigid plate 231 must be maintained during the removal of the sealing element 200. This pressure can be maintained manually, or by means of the thread of the object 5 and the tappings of the passage 222 and / or the orifice 232.

[0077] When the sealing element 200 is removed, the seal 240 can be held in the second position by the object 5, as illustrated in the Figure 5 , or can return to its first position by at least partially removing object 5, as illustrated in the figure 6 .

[0078] We will now describe a method for mounting the acoustic assembly allowing the insertion of the sealing element(s) into the acoustic panel. Such a method can in particular allow the through cavities present in the acoustic panel, which do not allow the attenuation of sound waves, to be blocked by a sealing element capable of attenuating the sound waves.

[0079] There figure 6 illustrates the sealing element 200 separated from the acoustic panel 100, which comprises an empty through cavity 120. In this configuration, the sealing gasket 240 of the sealing element 200 is in its first position, called sealing or resting.

[0080] To insert the sealing element(s) 200 into the acoustic panel 100, an object 5 is inserted inside the passage 222 of the body 220 and, if a fixing plate 233 is present in the sealing cavity 230, inside the orifice 232 of the fixing plate 233, as illustrated in the Figure 5 The object 5 is inserted from the first face 220a of the body 220 of the sealing element 200 to the interior of the sealing cavity 230.

[0081] The inserted object 5 pushes against the rigid plate 231, to increase the distance between the rigid plate 231 and the second face 220b of the body 220. If the closure element does not include a rigid plate 231, the inserted object can push directly on the seal 240, provided that the latter is sufficiently strong.

[0082] Under the action of the inserted object 5, the deformable joint 240 gradually stretches between the rigid plate 231 and the second face 220b of the body 220 until it reaches its second position, called assembly or disassembly, illustrated in the Figure 5 In this second position, the deformable seal 240 is able to pass through the acoustic panel 100, that is to say to pass inside the through cavity 120 to allow the insertion of the sealing element 200 into the acoustic panel 100.

[0083] Object 5 can have the same characteristics as before. In the example shown on the figures 3 to 6 , the object inserted into the body 220 of the closure element 200 is identical for assembly and disassembly. It is of course not outside the scope of the invention if different elements are used to deform the seal for assembly and disassembly.

[0084] When the sealing gasket 240 is deformed into its second position, called mounting or dismounting, the sealing element 200 can be inserted into the acoustic panel 100, as illustrated in the figure 4 To avoid damaging the seal 240, the pressure of the object 5 on the rigid plate 231 must be maintained during the insertion of the sealing element 200. This pressure can be maintained manually, or by means of the thread of the object 5 and the tappings of the passage 222 and / or the orifice 232.

[0085] When the sealing element 200 is placed in the through cavity 120 of the acoustic panel 100, the inserted object 5 is removed. The sealing gasket 240 thus returns to its first position, called the sealing or rest position. In this configuration, the first face 220a of the body 220 of the sealing element 200 is located in the extension of the first face 100a of the acoustic panel 100. Thus, in this configuration, the sealing element 200 seals with the second face 100b of the acoustic panel 100 and allows acoustic attenuation of all the sound waves directed towards the relatively uniform first face of the assembled acoustic assembly 1, which comprises the first face 100a of the acoustic panel 100 and the first face 220a of the body 220 of the sealing element 200.Consequently, the sealing element 200 ensures good acoustic performance of the assembled acoustic assembly 1 despite the through cavities 120 present in the acoustic panel 100.

[0086] We will now describe a method for repairing an acoustic panel to replace a damaged area of ​​said acoustic panel. figure 7illustrates for example an acoustic panel 1000 comprising a plurality of acoustic cells 1100, including two adjacent acoustic cells 1101 and 1102 which have been damaged by damage or damage 1300. The acoustic cells 1100 are delimited by partitions 1110 and extend between a first face 1000a of the acoustic panel 1000 and a second face 1000b of the acoustic panel 1000 opposite the first face 1000b. In the example presented, the acoustic cells 1100 comprise complex hollow acoustic elements 1120. The first face 1000a of the acoustic panel 1000 is covered by an upper acoustic skin 1010, which comprises a plurality of perforations 1010a. The acoustic panel 1000 may have all the characteristics and variations described previously in the context of the example of the acoustic panel 100.

[0087] A through cavity 1200 is produced in a direction X in the acoustic panel 1000, by removing the acoustic cells 1101 and 1102 which were at least partly damaged, as illustrated in the figure 8 . In fact, it is more interesting from an acoustic point of view to remove complete acoustic cells, to be able to replace them with other acoustic cells.

[0088] A sealing element 2000 is used to fill the through cavity 1200 thus formed, the shape of the body 2200 of which matches the geometry of said through cavity 1200. Preferably, the acoustic impedance of the sealing element 2000 generally corresponds to the acoustic impedance of the area of ​​the acoustic panel 1000 which has been removed.

[0089] In the example illustrated on the figure 8, two acoustic cells 1101 and 1102 have been removed from the acoustic panel 1000. Thus, to obtain a similar acoustic impedance, the sealing element 2000 also contains two acoustic cells 2100 extending in the X direction between a first face 2200a of the body 2200 and a second face 2200b of the body 2200.

[0090] The acoustic cells 2100 comprise complex hollow acoustic elements 2120 having a shape that gradually tapers between a base and a top.

[0091] The first face 2200a of the body 2200 is covered by one or more upper acoustic skins 2210, such that each acoustic cell 2100 of the sealing element 2000 is covered by an upper acoustic skin 2210, which comprises a plurality of perforations 2210a.

[0092] The body 2200 of the closure element 2000 further comprises a passage 2220, which may have all the features, functions and variations described above. The closure element 2000 further comprises a cavity 2300 delimited at least in part by a seal 2400, the latter being able to have all the features, functions and variations described above.

[0093] The sealing element 2000 can then be inserted into the acoustic panel 1000 according to the assembly method described previously, by deforming the seal 2400.

[0094] In the examples presented above, the body of the closure element only contains two acoustic cells. It is of course not outside the scope of the invention if the closure element is adapted to contain more than two acoustic cells, as illustrated in the figures 9 and 10The shape of the deformable seal and the plates is adapted, and the number of passages can be increased.

[0095] According to a first example, if the sealing element contains several acoustic cells aligned in a line or if the sealing element has large dimensions, the number of passages can be increased to ensure the correct deformation of the sealing gasket between its first position and its second position. For example, the figure 9 illustrates a sealing element 300 comprising a body 320 enclosing three acoustic cells 310 delimited by partitions 311 extending in a direction X between a first face 320a of the body 320 and a second face 320b of the body 320. The acoustic cells 310 comprise complex hollow acoustic elements 312 having a shape gradually narrowing between a base 312a and a top 312b.

[0096] The first face 320a of the body 320 is covered by one or more upper acoustic skins 321, such that each acoustic cell 310 of the sealing element 300 is covered by an upper acoustic skin 321, which comprises a plurality of perforations 321a.

[0097] The body 320 of the closure element 300 further comprises two passages 322 extending in the direction X from the first face 320a of the body 320 to the second face 320b of the body 320. Each passage 322 is located between two acoustic cells 310 so that, in each surface perpendicular to the axis X, the centers of the acoustic cells 310 and the passages 322 are aligned. The passages 322 may be tapped. The passages 322 may be cylindrical and may have a cross-section with a diameter of between 3 mm and 10 mm, preferably 5 mm.

[0098] The passages 322 open onto the first face 320a of the body 320, preferably onto a portion of the first face 320a which is not covered by an upper acoustic skin 321, and onto the second face 320b of the body 320.

[0099] The sealing element 300 further comprises the body 320, a sealing cavity 330 extending from the second face 320b of the body 320. As illustrated in the figure 9 , the sealing cavity 330 is delimited by the second face 320b of the body 320, by a deformable sealing joint 340 and by a rigid plate 331.

[0100] The rigid plate 331 and the sealing gasket 340 may have all the characteristics and variations described above, and their shape is elongated to adapt to the geometry of the closure element 300.

[0101] The deformable seal 340 may be attached to the second face 320b of the body 320 by means of a fixing plate 333. The fixing plate 333 may have all the characteristics and variations described above, but in this example comprises two orifices 332 located in the extension of the two passages 322, in order to allow the passage of one or more elements through the fixing plate 333. The orifices 332 may be tapped. If the passages 322 are tapped, the same tapping characteristics are used for the orifices 332. The portions of the fixing plate 333 located around the orifice 332 may extend towards the interior of the cavity 330, in order to ensure better guidance of any object inserted inside the passages 322 and the orifices 332.

[0102] If the closure element 300 does not include a fixing plate, the passages 322 of the body 320 open directly into the sealing cavity 330.

[0103] The deformation of the seal 340 from its first position to its second position can be achieved by the insertion of two separate objects, or by the insertion of a single object comprising two branches, each branch being adapted to one of the passages 322.

[0104] According to a second example, if the sealing element contains several acoustic cells which are not aligned in a line, the passage of the sealing element can be placed in the center of at least three acoustic cells to ensure the correct deformation of the sealing gasket between its first position and its second position. For example, the figure 10illustrates a closure element 400 in section comprising a body 420 enclosing three acoustic cells 410 arranged in a “triangle” and delimited by partitions 411 extending between a first face and a second face of the body. The acoustic cells 410 comprise complex hollow acoustic elements 412 having a shape gradually narrowing between a base and a top.

[0105] The body 420 of the sealing element 400 further comprises a passage 420 extending from the first face to the second face of the body. The passage 420 is located between the three acoustic cells 410 such that, in each surface perpendicular to the axis of the passage 420, the center of the passage 420 is located at the center of the triangle formed by the centers of the acoustic cells 410. The passage 420 may have all the characteristics and variations described above.

[0106] In this example illustrated on the figure 10, the seal will have a triangular shape.

[0107] In the examples presented above, the body of the closure element contains at least two acoustic cells. It is of course not outside the scope of the invention if the closure element contains only one acoustic cell.

[0108] For example, the figure 11 illustrates a sealing element 500 comprising a body 520 enclosing a single acoustic cell 510 extending in a direction X between a first face 520a of the body 520 and a second face 520b of the body 520. The acoustic cell 510 comprises a complex hollow acoustic element 512 having a shape gradually narrowing between a base 512a and a top 512b.

[0109] The sealing element 500 further comprises the body 520, a sealing cavity 530 extending from the second face 520b of the body 520. As illustrated in the figure 11, the sealing cavity 530 is delimited by the second face 520b of the body 520, by a deformable sealing joint 540 and by a rigid plate 531.

[0110] The rigid plate 531 and the sealing gasket 540 may have all the characteristics and variations described above, and their shape is rounded to adapt to the geometry of the closure element 500.

[0111] The deformable seal 540 can be fixed to the second face 520b of the body 520 by means of a fixing plate 533. The fixing plate 533 can have all the characteristics and variations described previously, but in this example comprises a single orifice 532, which opens on one side into the cavity 530 and on the other side inside the body 520. The orifice 532 allows the passage of one or more objects through the fixing plate 533, the inserted object(s) allowing the deformation of the seal 540 between its first position, called sealing or rest position, and its second position, called mounting or dismounting position.

[0112] Preferably, the orifice 532 is directed in the X direction and passes through the fixing plate 533 in its center. The orifice 532 may be tapped. The orifice 532 may be cylindrical and may have a cross-section with a diameter of between 3 mm and 10 mm, preferably 5 mm. The portions of the fixing plate 533 located around the orifice 532 may extend towards the inside of the cavity 530, in order to ensure better guidance of any object inserted inside the orifice 532.

[0113] Preferably, the fixing plate 533 may comprise a valve at the inlet or outlet of the orifice 532, which may open due to the insertion of an object inside the orifice. This valve makes it possible to plug the orifice 532 when no object is inserted inside said orifice 532, so as to obtain better controlled acoustic attenuation of the closing element 500.

[0114] The first face 520a of the body 520 is covered by an upper acoustic skin 521, which comprises a plurality of perforations 521a. The upper acoustic skin 521 may be removable: it may be removed to allow the insertion of the object used to deform the seal between its first and second position, then replaced to ensure its acoustic function. The upper acoustic skin may also be provided with a perforation located in the extension of the orifice which passes through the fixing plate, of sufficient size to allow the insertion of the object used to deform the seal between its first and second position without needing to remove the removable acoustic skin.

Claims

1. An acoustic assembly (1) comprising a multicellular acoustic panel (100) having at least one through cavity (120) along a direction X, characterized in that the acoustic assembly (1) further comprises at least one sealing element (200) comprising a body (220) enclosing one or more acoustic cells (210), the body (220) being able to be inserted into the cavity (120) and extending along the direction X between a first face (220a) and a second face (220b), the sealing element (200) further comprising a seal (240) on the second face (220b) of the body (220) able to ensure the sealing with the acoustic panel (100).

2. The acoustic assembly (1) as claimed in 1, wherein the body (220) of the sealing element (200) fits the shape of the cavity (120) when it is inserted into said cavity (120).

3. The acoustic assembly (1) as claimed in claim 1 or 2, wherein the seal (240) of the sealing element (200) is deformable between a rest or sealing position, wherein the seal (240) extends beyond the periphery of the body (220) perpendicular to the direction X, and a mounting or dismounting position, wherein the seal (240) does not extend beyond the periphery of the body (220) perpendicular to the direction X.

4. The acoustic assembly (1) as claimed in claim 3, wherein the sealing element (200) further comprises a passage (222) extending from the seal (240) and opening onto the first face (220b) of the body (220), configured to allow the insertion of an object (5) able to deform the seal (240) from its rest position into its mounting or dismounting position.

5. The acoustic assembly (1) as claimed in claim 4, wherein the passage (222) comprises at least one tapped portion.

6. The acoustic assembly (1) as claimed in any of claims 1 to 5, wherein each cell (110) of the acoustic panel (100) and each cell (210) of the sealing element (200) comprises a hollow acoustic element (112, 212) having a shape gradually tapering between a base (112a, 212a) and an apex (112b, 212b).

7. A method for mounting an acoustic assembly (1) as claimed in any of claims 1 to 6, comprising the placing of at least one sealing element (200) in at least one through cavity (120) of the multicellular acoustic panel (100), said sealing element (200) occupying the volume defined by the cavity (120) such that the first face (220a) of the body (220) of the sealing element (200) is located in the extension of a first face (100a) of the acoustic panel (100) and the seal (240) of the sealing element (200) ensures the sealing between the second face (220b) of the body (220) of the sealing element (200) and a second face (100b) of the acoustic panel (100) opposite the first face (100a) of the panel (100).

8. A method for dismounting an acoustic assembly (1) as claimed in any of claims 1 to 6, comprising the removing of at least one sealing element (200) from a through cavity (120) of the multicellular acoustic panel (100) by deforming the seal (240) of said sealing element (200).

9. A method for repairing a multicellular acoustic panel (1000) comprising a damaged area (1300), comprising the following steps: - producing at least one through cavity (1200) along a direction X by removing the cells (1101, 1102) present at least in part in the damaged area (1300), - supplying at least one sealing element (2000) comprising a body (2200) enclosing one or more acoustic cells (2100), the body (2200) fitting the shape of the cavity (1200) and extending along the direction X between a first face (2200a) and a second face (2200b), the sealing element (2000) further comprising a seal (2400) on the second face (2200b), - placing said sealing element (2000) in the through cavity (1200), the sealing element (2000) occupying the volume defined by the cavity such that the first face (2200a) of the body (2200) of the sealing element (2000) is located in the extension of a first face (1000a) of the acoustic panel (1000) and the seal (2400) of the sealing element (2000) ensures the sealing between the second face (2200b) of the body (2200) of the sealing element (2000) and a second face (1000b) of the acoustic panel (1000) opposite the first face (1000a).

10. The repairing method as claimed in claim 9, wherein the seal (2400) of the sealing element (2000) is deformable between a rest or sealing position, wherein the seal (2400) extends beyond the periphery of the body (2200) perpendicular to the direction X, and a mounting or dismounting position, wherein the seal (2400) does not extend beyond the periphery of the body (2200) perpendicular to the direction X, and wherein the sealing element (2000) further comprises a passage (2220) extending from the seal (2400) and opening onto the first face (2200a) of the body (2200), the placing of the sealing element (2000) in the through cavity (1200) comprising the following steps: - inserting an object into the passage (2220) to deform the seal (2400) from its rest or sealing position into its mounting or dismounting position, - placing the sealing element (2000) in the cavity (1200) of the multicellular acoustic panel (1000) while retaining the seal (2400) in its mounting or dismounting position, said sealing element (2000) occupying the volume defined by the cavity (1200) such that the first face (2200a) of the body (2200) of the sealing element (2200) is located in the extension of a first face (1000a) of the acoustic panel (1000), - removing the object inserted into the passage (2220) to allow the seal (2400) to regain its rest or sealing position, such that the seal (2400) ensures the sealing between the second face (2200b) of the body (2200) of the sealing element (2000) and a second face (1000b) of the acoustic panel (1000) opposite the first face (1000a).

11. A sealing element (200) comprising a body (220) extending along a direction X between a first face (220a) and a second face (220b) and enclosing one or more acoustic cells (210), the first face (220a) comprising one or more acoustic skins (221), said sealing element (200) further comprising a sealing cavity (230) delimited at least by the second face (220b) of the body (220) and by a deformable seal (240).

12. The sealing element (200) as claimed in claim 11, wherein the seal (240) is deformable between a rest or sealing position, wherein the seal (240) extends beyond the periphery of the body (220) perpendicular to the direction X, and a mounting or dismounting position, wherein the seal (240) does not extend beyond the periphery of the body (220) perpendicular to the direction X.

13. The sealing element (200) as claimed in claim 12, further comprising a passage (222) extending from the sealing cavity (230) and opening onto the first face (220b) of the body (220), configured to allow the insertion of an object (5) able to deform the seal (240) from its rest position into its mounting or dismounting position.

14. The sealing element (200) as claimed in any of claims 11 to 13, further comprising a stiff plate (231) extending perpendicular to the direction X such that the sealing cavity (230) is delimited by the second face (220b) of the body (220), by the deformable seal (240) and by the stiff plate (231), the deformable seal (240) connecting the edges of the stiff plate (231) to the second face (220b) of the body (220).