Method for obtaining a blade grid for an aircraft thrust reverser device from tubular preforms, blade grid obtained from this method

Abstract

Method for obtaining a blade grid for an aircraft thrust reverser device from tubular preforms, blade grid obtained from this method The invention relates to a method for obtaining a blade grid for an aircraft thrust reverser device, said method comprising: a step of manufacturing tubular preforms (76.1, 76.2) each comprising transverse and longitudinal sections (78, 80, 82, 84) which form a single piece, delimit a cell of the blade grid and constitute at least one layer of the blades as well as longitudinal walls of the blade grid located around the cell, a step of assembling the tubular preforms (76.1, 76.2) which consists of connecting the transverse sections (78, 80) of two tubular preforms (76.1, 76.2) in a manner to form a common blade, and / or the longitudinal sides (82, 84) of two tubular preforms (76.1, 76.2) so as to form a section of a common longitudinal wall.The invention also relates to a blade grid obtained from such a process. Figure 14.

Description

Title of the invention: Method for obtaining a blade grid for an aircraft thrust reverser device from tubular preforms, blade grid obtained from this method

[0001] The present application relates to a method for obtaining a blade grid for an aircraft thrust reverser device from tubular preforms, to a blade grid obtained from this method and to an aircraft comprising at least one such blade grid.

[0002] According to an embodiment visible in Figures 1 to 3, an aircraft 10 comprises several propulsion units 12 positioned under each of the wings 14 of the aircraft 10 and connected to the latter by masts 16. Each propulsion unit 12 comprises a motorization 18 positioned inside a nacelle 20. The motorization 18 comprises a fan which has an axis of rotation A18.

[0003] For the remainder of the description, a longitudinal direction is parallel to the axis of rotation A18. A longitudinal plane is a plane containing the axis of rotation A18 and a transverse plane is a plane perpendicular to the axis of rotation A18. The concepts front / upstream and rear / downstream refer to the direction of flow of an air flow in the nacelle 20, the latter flowing from the front (upstream) to the rear (downstream).

[0004] The nacelle 20 has an approximately tubular shape and delimits with the motorization 18 an annular duct 22 in which a secondary air flow flows. The nacelle 20 comprises an upstream section 24 called the air inlet, a middle section 26 in which the fan of the motorization 18 is positioned and a downstream section 28 which has a trailing edge 30.

[0005] The nacelle 20 comprises a thrust reverser device 34 positioned at the downstream section 28 and configured to occupy an activated state in which it diverts at least a portion of the secondary air flow circulating in the annular duct 22 towards the outside and upstream of the nacelle 20 as well as an inactivated state in which it does not divert the secondary air flow circulating in the annular duct 22.

[0006] The thrust reversal device 34 comprises at least one movable part 36 making it possible to generate at least one lateral opening 38 (visible in [Fig.2]) passing through the nacelle 20.

[0007] The thrust reverser device 34 comprises a deflection system 40 configured to occupy a retracted position, when the thrust reverser device 34 is in the inactivated state, in which the deflection system 40 does not interfere with the secondary airflow as well as a deployed position, when the thrust reverser device 34 is in the activated state, in which the deflection system 40 interferes with the secondary airflow and directs it towards the side opening 38.

[0008] The thrust reverser device 34 also comprises an orientation system 42 configured to orient the air flow deflected by the deflection system 40. According to one embodiment, the orientation system 42 comprises several blade grids 44 called cascades and positioned at each lateral opening 38.

[0009] According to an embodiment visible in Figures 4 and 5, each blade grid 44 comprises longitudinal walls 46 positioned in approximately longitudinal planes as well as blades 48 positioned in approximately transverse planes. The longitudinal walls 46 and the blades 48 delimit cells 50.

[0010] The blades 48 have a profile for deflecting the air flow exiting upstream via each lateral opening 38. For this purpose, each blade 48 is curved and has a depth P, as illustrated in [Fig.5].

[0011] According to one arrangement, the blade grid 44 comprises five longitudinal walls 46 delimiting four rows of blades 48, sixteen blades 48 for each row and seventy-two cells 50.

[0012] Given their geometry and in particular the low depth P of the blades 48, the blade grids 44 have a large number of cells 50 and therefore a relatively high mass, which is penalizing in terms of on-board mass and energy consumption for an aircraft.

[0013] As illustrated in Figures 6 and 7, a blade grid 44 is made of composite material by molding, using for each cell 50 a core 52 configured to expand.

[0014] According to one operating mode, a method for obtaining a blade grid 44 comprises a step of stacking fiber plies to obtain first preforms 46', one for each longitudinal wall 46, and second preforms 48', one for each blade 48. As illustrated in [Fig. 6], the first preforms 46' are substantially planar. The second preforms 48' have an H-shaped section provided with first and second wings 48.1', 48.2' at each end, intended to be pressed against first preforms 46'.

[0015] The method for obtaining a grid of blades 44 comprises, for each row of blades, a step of placing, alternating them, second preforms 48' and cores 52 between two first preforms 46' substantially parallel to each other, the first wings 48.1' of all the second preforms 48' being pressed against the first preform 46' located on the left, the second wings 48.2' of all the second preforms 48' being pressed against the first preform 46' located on the right. When all the first and second preforms 46', 48' are positioned, the method of obtaining comprises a consolidation or polymerization step, to connect the first and second preforms 46', 48' together, during which the assembly is compressed and subjected to a rise in temperature.

[0016] The rise in temperature causes an expansion of the cores 52 which compress the second preforms 48'. After the consolidation or polymerization step, the blade grid 44 obtained and the cores 52 are cooled, which causes the cores 52 to shrink. The production method then comprises a demolding step during which the cores 52 are extracted from the blade grid 44.

[0017] Given the relatively small depth P of the blades 48, the cores 52 compress them correctly during the consolidation or polymerization step, which makes it possible to control the structural integrity of the blade grid 44 obtained.

[0018] This production method, suitable for blades with a small depth, is not suitable if the blades have a significant depth, the cores not expanding sufficiently to compress the preforms. Furthermore, the larger the core dimensions, the more complex it is to control its deformation. In the presence of blades with a significant depth, it is necessary to provide relatively complex slide cores which are difficult, or even impossible, to extract.

[0019] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0020] To this end, the invention relates to a method for obtaining a blade grid for an aircraft thrust reverser device, said blade grid comprising at least first and second longitudinal walls as well as blades positioned between said first and second longitudinal walls and connected to the latter, the longitudinal walls and the blades delimiting cells.

[0021] According to the invention, the obtaining method comprises: a. a step of manufacturing at least first and second tubular preforms each comprising a first transverse panel forming at least one layer of a first blade, a second transverse panel forming at least one layer of a second blade, a first longitudinal panel forming at least one layer of a first longitudinal wall and a second longitudinal panel forming at least one layer of a second longitudinal wall; the first and second transverse panels and the first and second longitudinal panels forming a single piece and delimiting a cell, b. a step of assembling the first and second tubular preforms consisting of connecting: i. the first and second transverse sides of the first and second tubular preforms so as to form a common blade, and / or ii. the first and second longitudinal sides of the first and second tubular preforms so as to form a section of a common longitudinal wall.

[0022] According to the invention, a blade grid is obtained from a multitude of tubular preforms, one for each cell, each manufactured using relatively simple tooling which guarantees the structural integrity of said preforms. This makes it possible to obtain, after a step of assembling said preforms, a blade grid which has excellent mechanical properties and blades with, for at least some, a relatively significant depth.

[0023] According to another characteristic, the manufacturing step comprises, for at least one tubular preform, at least one compression phase of said tubular preform and at least one baking or polymerization phase during which said tubular preform is compressed and at least partially baked or polymerized.

[0024] According to another characteristic, prior to the compression phase, the manufacturing step comprises, for at least one tubular preform, a draping phase during which fiber plies are positioned on or against at least one mold which has first, second, third and fourth interior faces shaped respectively like the first transverse and longitudinal panels as well as the second transverse and longitudinal panels.

[0025] According to another characteristic, the compression phase consists of using at least one expandable element configured to occupy retracted and expanded states, positioning it in the retracted state between the different sides of a tubular preform positioned in the mold and expanding the expandable element so as to compress said tubular preform.

[0026] According to another characteristic, the fiber plies are positioned on the first, second, third and fourth interior faces when the mold has a tubular shape, by alternating first fiber plies each arranged only opposite one of the first, second, third and fourth interior faces as well as second corner fiber plies arranged astride two interior faces among the first, second, third and fourth interior faces.

[0027] According to another characteristic, the mold comprises several parts configured to occupy assembled and disassembled states. In addition, first fiber plies each arranged only opposite one of the first, second, third and fourth interior faces are positioned when the parts of the mold are in the disassembled state.

[0028] According to another characteristic, the step of assembling the first and second tubular preforms consists of pressing one against the other and connecting the first and second transverse sections of the first and second tubular preforms so as to form a blade as well as aligning the first longitudinal sections of the first and second tubular preforms so as to form at least a portion of the first longitudinal wall and the second transverse sections of the first and second tubular preforms so as to form at least a portion of the first longitudinal wall.

[0029] According to another characteristic, at least some blades each comprise a body and a wing substantially perpendicular to the body. In addition, the first transverse panel extends over at least a portion of a blade at its body and its wing, the second transverse panel extending over at least a second portion of a blade at its body and its wing, the first and second portions being complementary so that when they are assembled the first transverse panel of a first tubular preform and the second transverse panel of a second tubular preform form a complete blade.

[0030] According to another characteristic, the method for obtaining a blade grid comprises a step of manufacturing at least one longitudinal preform forming a layer of a longitudinal wall and a step of assembling the longitudinal preform and the tubular preforms.

[0031] According to another characteristic, two tubular preforms are connected by at least one ply of glue and / or at least one ply of fibers interposed between the two tubular preforms.

[0032] According to another characteristic, during the manufacturing step, each tubular preform is partially cooked or polymerized, a final cooking or polymerization phase being carried out subsequently at the latest during the assembly step.

[0033] According to another characteristic, during the manufacturing step, each tubular preform is completely cooked or polymerized.

[0034] The invention also relates to a blade grid obtained from a production method according to one of the preceding characteristics as well as an aircraft comprising at least one such blade grid.

[0035] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the appended drawings, among which:

[0036] [Fig. 1] is a perspective view of an aircraft and a propulsion assembly illustrating one embodiment,

[0037] [Fig.2] is a side view of a propulsion assembly illustrating an embodiment of the prior art,

[0038] [Fig.3] is a schematic section of a propulsion assembly equipped with a thrust reverser device in the inactivated state illustrating an embodiment of the prior art,

[0039] [Fig.4] is a perspective view of a blade grid illustrating a mode of rea- prior art,

[0040] [Fig.5] is a longitudinal section along the PV plane of the blade grid visible on [Fig.4],

[0041] [Fig.6] is a schematic representation of a step of installing walls longitudinal, blade and core sections illustrating an embodiment of the prior art,

[0042] [Fig.7] is a top view of a blade grid during a consolidation step or polymerization illustrating an embodiment of the prior art,

[0043] [Fig.8] is a perspective view of a blade grid illustrating a mode of rea lization of the invention,

[0044] [Fig.9] is a longitudinal section along plane P-IX of the blade grid visible on [Fig.8],

[0045] [Fig. 10] is a perspective view of a blade illustrating one embodiment of the invention,

[0046] [Fig. 11] is a longitudinal section of a tool and a tubular preform illustrating an embodiment of the invention,

[0047] [Fig. 12] is a section along a median surface of a tool and a tubular preform illustrating an embodiment of the invention

[0048] [Fig. 13] is a section along a median surface of a tool and a tubular preform illustrating another embodiment of the invention,

[0049] [Fig. 14] is a perspective view of tubular preforms before an assembly step illustrating an embodiment of the invention,

[0050] [Fig. 15] is a perspective view of the tubular preforms visible in [Fig. 14] after an assembly step,

[0051] [Fig. 16] is a schematic section along a median surface of an assembly of several tubular preforms illustrating an embodiment of the invention,

[0052] [Fig. 17] is a longitudinal section of a portion of an assembly of tubular preforms illustrating an embodiment of the invention,

[0053] [Fig. 18] is a perspective view of a portion of a blade grid before an assembly step illustrating an embodiment of the invention,

[0054] [Fig. 19] is a schematic section along a median surface of an assembly of several tubular preforms illustrating an embodiment of the invention,

[0055] [Fig.20] is a schematic representation of a blade grid with different moments of an assembly step illustrating an embodiment of the invention.

[0056] According to one application, an aircraft comprises at least one thrust reverser device which comprises at least one blade grid 60.

[0057] According to an embodiment visible in Figures 8 to 10, a blade grid 60 comprises at least first and second longitudinal walls 62, 62' positioned in approximately longitudinal planes as well as blades 64, 64' positioned between said first and second longitudinal walls 62, 62', connected to the latter and positioned in approximately transverse planes; the longitudinal walls 62, 62' and the blades 64, 64' delimiting cells 66.

[0058] Each longitudinal wall 62, 62' extends between inner and outer edges 62.1, 62.2. Each blade 64, 64' extends between inner and outer edges 64.1, 64.2. According to one arrangement, the inner edges 62.1, 64.1 of the longitudinal walls 62, 62' and the blades 64, 64' are positioned at a first surface forming an inner surface F60 of the blade grid 60, the outer edges 62.2, 64.2 of the longitudinal walls 62, 62' and the blades 64, 64' being positioned at a second surface forming an outer surface F60' of the blade grid 60. According to one configuration, the inner and outer surfaces F60, F60' are curved to adapt to the curvature of a nacelle. Of course, the invention is not limited to this geometry for the outer and inner surfaces F60, F60'.

[0059] A median surface is a surface substantially parallel to the inner and outer surfaces F60, F60', located between said inner and outer surfaces F60, F60'.

[0060] The blades 64, 64' have inner and outer edges 64.1, 64.2 which are substantially parallel to each other and oriented in a transverse direction which is substantially perpendicular to the longitudinal direction.

[0061] According to one configuration, each blade 64, 64' has a substantially constant section in the transverse direction. The blades 64, 64' may have identical sections. Alternatively, as illustrated in [Fig.9], the blades 64, 64' have different sections from one blade to another.

[0062] According to an embodiment visible in [Fig. 10], at least some blades 64 each comprise a body 68 which extends between a first edge 68.1, corresponding to the inner edge 64.1 of the blade 64, and a second edge 68.2 as well as a wing 70 situated in the extension of the body 68 which extends between a first edge 70.1, corresponding to the outer edge 64.2 of the blade 64, and a second edge 70.2 secured to the second edge 68.2 of the body 68. In a longitudinal plane, the wing 70 is substantially perpendicular to the body 68. For each blade 64, the body 68 and the wing 70 form a single and same piece.

[0063] According to one configuration, the wing 70 is substantially flat and located at the level of the outer surface F60' of the blade grid 60.

[0064] The blade 64 has a depth P which corresponds to a maximum distance separating a plane PL passing through the inner and outer edges 64.1, 64.2 of the blade 64 and a generatrix C of the body 68 furthest from the plane PL.

[0065] According to one configuration, the depth P of the blade 64 is relatively large. By relatively large, it is meant that the depth P does not allow a preform intended to form a blade to be correctly compressed using cores simple according to a prior art method visible in figures 6 and 7.

[0066] According to one arrangement, the blade grid 60 comprises three longitudinal walls 62, 62' defining two rows of blades 72, 72' as well as four blades 64, 64' per row of blades, the longitudinal walls 62 and the blades delimiting eight cells 66.

[0067] Taking into account the depth P of the blades 64, 64', it is possible to reduce their number, which tends to reduce the mass of the blade grid 60.

[0068] Generally, a blade grid 60 comprises several rows of blades 72, 72'. However, a blade grid 60 could comprise only a single row of blades 72.

[0069] Whatever the embodiment, the blade grid 60 comprises longitudinal end walls corresponding to the most spaced longitudinal walls 62. It extends between a front end 60.1 located approximately in a first transverse plane and a rear end 60.2 located approximately in a second transverse plane.

[0070] According to one embodiment, the blade grid 60 comprises at least one end plate 74 located at the front or rear end 60.1, 60.2, connecting the longitudinal end walls and positioned at the outer surface F60' of the blade grid 60. According to a configuration visible in FIGS. 14 and 15, each end plate 74 is a substantially rectangular strip of material which has long sides substantially parallel to the transverse direction. At least one end plate 74 comprises at least one through-hole 74.1 configured to fix the blade grid 60 to a structure of an aircraft.

[0071] According to one arrangement, the blade grid 60 comprises two end plates 74, 74' positioned at the front and rear ends 60.1, 60.2 of the blade grid 60.

[0072] As illustrated in Figures 11 to 20, a method of obtaining a blade grid 60 comprises: a. a step of manufacturing at least first and second tubular preforms 76.1, 76.2 each comprising a first transverse panel 78 forming at least one layer of a first blade 64, a second transverse panel 80 forming at least one layer of a second blade 64', a first longitudinal panel 82 forming at least one layer of a first longitudinal wall 62 as well as a second longitudinal panel 84 forming at least one layer of a second longitudinal wall 62'; the first and second transverse panels 78, 80 as well as the first and second longitudinal panels 82, 84 forming a single piece and delimiting a cell 66, b. a step of assembling the first and second tubular preforms 76.1, 76.2 consisting of pressing one against the other and connecting: i. the first and second transverse panels 78, 80 of the first and second tubular preforms 76.1, 76.2 so as to form a common blade 64, and / or ii. the first and second longitudinal sections 82, 84 of the first and second tubular preforms 76.1, 76.2 so as to form a section of a common longitudinal wall 62.

[0073] According to one embodiment, the step of assembling the first and second tubular preforms 76.1, 76.2 consists of pressing one against the other and connecting the first and second transverse sections 78, 80 of the first and second tubular preforms 76.1, 76.2 so as to form a blade 64 as well as aligning the first longitudinal sections 82 of the first and second tubular preforms 76.1 to 76.2 so as to form at least a portion of the first longitudinal wall 62 and the second transverse sections 84 of the first and second tubular preforms 76.1 to 76.2 so as to form at least a portion of the first longitudinal wall 62.

[0074] According to one configuration, the first and second longitudinal sections 82, 84 each extend from the inner edge 62.1 to the outer edge 62.2 of a longitudinal wall 62, 62'. Alternatively, the first longitudinal section 82 extends over a first portion of a longitudinal wall 62 and the second longitudinal section 84 extends over a second portion of a longitudinal wall 62, the first and second portions being complementary so that the first longitudinal section 82 of a first tubular preform 76.1 and the second longitudinal section 84 of a second tubular preform 76.2 form a section of a longitudinal wall 62, 62'.

[0075] According to one configuration, each of the first and second transverse sections 78, 80 extends at the level of the body 68 and the wing 70 of a blade 64. Thus, as illustrated in FIGS. 11 and 17, the first transverse section 78 forms a first part of the body 68 and the wing 70 of a blade 64 and the second transverse section 80 forms a second part of the body 68 and the wing 70 of a blade 64, the first and second parts being complementary so that the first transverse section 78 of a first tubular preform 76.1 and the second transverse section 80 of a second tubular preform 76.2 form a complete blade 64.

[0076] According to another configuration, only the first transverse panel 78 extends at the level of the wing 70 of a blade. According to this configuration, the second transverse panel 80 extends only at the level of the body 68 of the blade 64.

[0077] Whatever the configuration, the first transverse panel 78 extends over at least a portion of a blade 64 and the second transverse panel 80 extends over at least a second portion of a blade 64 complementary to the first portion so that when they are assembled, the first transverse panel 78 of a first tubular preform 76.1 and the second transverse panel 80 of a second tubular preform 76.2 form a complete blade 64.

[0078] According to a first operating mode, when a blade grid 60 comprises several rows of blades, the tubular preforms of the different rows are assembled during the same assembly step, as illustrated in FIGS. 14 and 15.

[0079] According to a second operating mode as illustrated in [Fig.20], when a blade grid 60 comprises several rows of blades, the assembly step comprises a first phase of assembly of each row consisting of connecting the tubular preforms 76.1 to 76.4 so as to form the rows of blades independently of one another, then a second phase of assembly of the different rows of blades consisting of connecting the rows of blades to one another.

[0080] According to an embodiment visible in Figures 14 and 18, the method for obtaining a blade grid comprises a step of manufacturing at least one longitudinal preform 86 forming a layer of a longitudinal wall 62 and a step of assembling the longitudinal preform 86 and the tubular preforms 76.1 to 76.4.

[0081] According to a first operating mode visible in Figures 14 to 16, a longitudinal preform 86 is interposed between the first longitudinal sections 82 of a first row of tubular preforms and the second longitudinal sections 84 of a second row of tubular preforms. According to this first operating mode, a longitudinal wall 62 located between two rows of blades comprises the first longitudinal sections 82 of the first row of tubular preforms, the longitudinal preform 86 as well as the second longitudinal sections 84 of the second row of tubular preforms.

[0082] According to a second operating mode visible in [Fig. 18], first and second longitudinal preforms 86, 86' are positioned on either side of a row of tubular preforms. According to this second operating mode, a longitudinal wall 62 comprises a longitudinal preform 86, 86' and the first or second longitudinal sections 82, 84 of a row of tubular preforms.

[0083] According to this second operating mode, when two rows of blades are assembled as illustrated in [Fig. 20], the longitudinal wall 62 located between the two rows of blades comprises the first longitudinal sections 82 of the first row of tubular preforms, two longitudinal preforms 86, 86' as well as the second longitudinal sections 84 of the second row of tubular preforms.

[0084] When the blade grid 60 comprises at least one end plate 74, 74', the method for obtaining a blade grid comprises a step of manufacturing each end plate 74, 74' and a step of assembling each end plate 74, 74' consisting of connecting it with at least one tubular preform 76.1 to 76.4, as illustrated in [Fig.20].

[0085] Each of the tubular and longitudinal preforms 76.1 to 76.4, 86, 86' is made of composite material and comprises fibers embedded in a thermo resin matrix curable or thermoplastic. Each end plate 74, 74' is made of a composite material and comprises fibers embedded in a thermosetting or thermoplastic resin matrix. According to one configuration, the tubular preforms 76.1 to 76.4, the longitudinal preforms 86, 86' and the end plates 74, 74' are made of the same composite material.

[0086] When the tubular preforms 76.1 to 76.4 as well as the possible longitudinal preforms 86, 86' and end plates 74, 74' each comprise a thermosetting resin matrix, each assembly step consists of connecting the tubular preforms 76.1 to 76.4 as well as the possible longitudinal preforms 86, 86' and end plates 74, 74' by gluing or co-firing.

[0087] When the tubular preforms 76.1 to 76.4 as well as the possible longitudinal preforms 86, 86' and end plates 74, 74' each comprise a thermoplastic resin matrix, each assembly step consists of connecting the tubular preforms 76.1 to 76.4 as well as the possible longitudinal preforms 86, 86' and end plates 74, 74' by gluing, co-baking, co-consolidation or welding.

[0088] According to a first assembly method, two tubular preforms 76.1, 76.2 are directly connected to each other, without any intermediate element.

[0089] According to a second assembly method, two tubular preforms 76.3, 76.4 (on the right in [Fig. 16]) are connected by at least one fold of glue 88.

[0090] According to a third assembly method, two tubular preforms 76.1, 76.2 (on the left in [Fig. 16]) are connected by at least one ply of fibers 90 (impregnated with resin or not impregnated) inserted between the two tubular preforms 76.1, 76.2. Glue plies 88, 88' may be inserted between the ply of fibers 90 and the tubular preforms 76.1, 76.2.

[0091] According to a fourth assembly method, two tubular preforms 76.1, 76.3 are connected by at least one longitudinal preform 86. Glue folds 88, 88' may be interposed between the longitudinal preform 86 and the tubular preforms 76.1, 76.2.

[0092] The use of glue folds 88 makes it possible to compensate for any roughness present on the surfaces of the tubular and elongated preforms 76.1 to 76.4, 86, 86' brought into contact during assembly.

[0093] Of course, the invention is not limited to these assembly methods. The latter can be combined and possibly other assembly methods can be implemented.

[0094] According to a first operating mode, each tubular or longitudinal preform 76.1 to 76.4, 86, 86' is partially cooked or polymerized during the manufacturing step which comprises a partial cooking or polymerization phase, a final cooking or polymerization phase being carried out subsequently at the latest during the assembly step.

[0095] According to a second operating mode, each tubular or longitudinal preform 76.1 to 76.4, 86, 86' is completely baked or polymerized during the manufacturing step which comprises a phase of complete baking or polymerization of the tubular or longitudinal preform 76.1 to 76.4, 86, 86'.

[0096] According to one embodiment, the step of manufacturing the tubular preforms 76.1 to 76.4 comprises, for at least one tubular preform 76.1 to 76.4 and preferably all of them, at least one phase of compression of said tubular preform 76.1 to 76.4 and at least one phase of curing or polymerization during which said tubular preform 76.1 to 76.4 is compressed and at least partially cured or polymerized.

[0097] According to one variant, the two phases of compression and cooking or polymerization are simultaneous. According to another variant, the cooking or polymerization phase ends before the end of the compression phase. According to this variant, the tubular preform 76.1 to 76.4 is compressed until at least partial cooking or polymerization is complete.

[0098] By way of example, during the compression and curing or polymerization phases, each tubular preform 76.1 to 76.4 is compressed at a pressure of between 2 and 7 bars and brought to a temperature of the order of 180°C. Of course, the invention is not limited to these pressures and this temperature. The latter vary depending on the materials of the tubular preforms 76.1 to 76.4.

[0099] At the end of the manufacturing step, each tubular preform 76.1 to 76.4 is sufficiently cooked or polymerized to maintain stable geometry and dimensions.

[0100] These phases of compression and at least partial cooking or polymerization make it possible to guarantee the structural integrity of the blade grid 60.

[0101] Prior to the compression phase, the step of manufacturing the tubular preforms 76.1 to 76.4 comprises, for at least one tubular preform 76.1 to 76.4, a draping phase during which fiber plies 92 are positioned on or against at least one rigid mold 94 which has first, second, third and fourth interior faces F1 to F4 shaped respectively like the first transverse and longitudinal panels 78, 82 and the second transverse and longitudinal panels 80, 84.

[0102] According to one embodiment, the mold 94 is tubular and made in one piece.

[0103] According to another embodiment, the mold 94 is tubular and comprises several parts 94.1 to 94.4, as illustrated in FIGS. 13, configured to occupy assembled and disassembled states. This solution facilitates demolding. According to one configuration, the mold 94 comprises four parts 94.1 to 94.4 each comprising one of the first, second, third and fourth interior faces F1 to F4.

[0104] According to a first operating mode visible in [Fig. 12], the fiber folds 92 are positioned on the first, second, third and fourth inner faces F1 to F4 when the mold 94 is assembled and has a tubular shape. According to this procedure, first fiber plies 92, each arranged only opposite one of the first, second, third and fourth inner faces F1 to F4, are positioned alternately with second corner fiber plies 92' arranged astride two inner faces among the first, second, third and fourth inner faces F1 to F4.

[0105] According to a second operating mode visible in [Fig. 13], the first fiber plies 92 each arranged only opposite one of the first, second, third and fourth inner faces F1 to F4 are positioned when the parts 94.1 to 94.4 of the mold 94 are in the disassembled state. This solution makes it possible to simplify the installation of the first fiber plies 92. According to this second operating mode, the second corner fiber plies 92' are not installed alternately with the first fiber plies 92 and are added once the latter have been installed.

[0106] Of course, the invention is not limited to these operating methods for placing the fiber folds 92, 92'.

[0107] According to an embodiment visible on 12, the compression phase consists of using at least one expandable element 96 configured to occupy retracted and expanded states, positioning it in the retracted state between the different sides 78 to 84 of the tubular preform 76.1 to 76.4 positioned in the mold 94 and expanding the expandable element 96 so as to compress said tubular preform 76.1 to 76.4. For this purpose, a tool for manufacturing the tubular preforms 76.1 to 76.4 comprises, in addition to the tubular mold 94, at least one expandable element 96 positioned in the mold 94 and configured to press the tubular preform 76.1 to 76.4 positioned in the mold 94 against the first, second, third and fourth interior faces F1 to F4 of the mold 94. According to one configuration, the expandable element 96 is an inflatable bladder.

[0108] The combination of the mold 94 and the expandable element 96 makes it possible, using a simple tool, to effectively compress each tubular preform 76.1 to 76.4 during the at least partial curing or polymerization phase, which ensures structural integrity of each tubular preform 76.1 to 76.4.

[0109] In addition, as illustrated in [Fig. 11], the manufacturing tooling may comprise a base 98 as well as a cover 100 positioned at the ends of the mold 94 so as to delimit a cavity with the latter.

[0110] Regardless of the embodiment and the tooling used, dividing the blade grid 60 into a multitude of tubular preforms 76.1 to 76.4, one for each cell 66, makes it possible to manufacture each of them using relatively simple tooling while guaranteeing the structural integrity of each of them, which makes it possible to obtain, after assembly of said preforms, a grid of blades which has excellent mechanical properties and blades with, for at least some, a relatively significant depth.

Claims

Claims

1. Method for obtaining a blade grid for an aircraft thrust reverser device, said blade grid (60) comprising at least first and second longitudinal walls (62, 62') as well as blades (64, 64') positioned between said first and second longitudinal walls (62, 62') and connected to the latter, the longitudinal walls (62, 62') and the blades (64, 64') delimiting cells (66); characterized in that the method of obtaining comprises: a. a step of manufacturing at least first and second tubular preforms (76.1, 76.2) each comprising a first transverse panel (78) forming at least one layer of a first blade (64), a second transverse panel (80) forming at least one layer of a second blade (64'), a first longitudinal panel (82) forming at least one layer of a first longitudinal wall (62) and a second longitudinal panel (84) forming at least one layer of a second longitudinal wall (62'); the first and second transverse panels (78, 80) and the first and second longitudinal panels (82, 84) forming a single piece and delimiting a cell (66), b. a step of assembling the first and second tubular preforms (76.1, 76.2) consisting of connecting: c. the first and second transverse sections (78, 80) of the first and second tubular preforms (76.1, 76.2) so as to form a common blade (64), and / or d. the first and second longitudinal sides (82, 84) of the first and second tubular preforms (76.1, 76.2) so as to form a section of a common longitudinal wall (62).

2. Method for obtaining a blade grid according to the preceding claim, characterized in that the manufacturing step comprises, for at least one tubular preform (76.1 to 76.4), at least one compression phase of said tubular preform (76.1 to 76.4) and at least one baking or polymerization phase during which said tubular preform (76.1 to 76.4) is compressed and at least partially baked or polymerized.

3. Method for obtaining a blade grid according to the preceding claim, characterized in that, prior to the compression phase, the manufacturing step comprises, for at least one tubular preform (76.1 to 76.4), a draping phase during which fiber plies (92) are positioned on or against at least one mold (94) which has first, second, third and fourth inner faces (F1 to F4) shaped respectively like the first transverse and longitudinal panels (78, 82) and the second transverse and longitudinal panels (80, 84).

4. Method for obtaining a blade grid according to the preceding claim, characterized in that the compression phase consists of using at least one expandable element (96) configured to occupy retracted and expanded states, positioning it in the retracted state between the different sides (78 to 84) of a tubular preform (76.1 to 76.4) positioned in the mold (94) and expanding the expandable element (96) so as to compress said tubular preform (76.1 to 76.4).

5. Method for obtaining a blade grid according to one of claims 3 to 4, characterized in that the fiber plies (92) are positioned on the first, second, third and fourth inner faces (F1 to F4) when the mold (94) has a tubular shape, by alternating first fiber plies (92) each arranged only opposite one of the first, second, third and fourth inner faces (F1 to F4) and second angle fiber plies (92') arranged astride two inner faces among the first, second, third and fourth inner faces (F1 to F4).

6. Method for obtaining a blade grid according to one of claims 3 to 4, characterized in that the mold (94) comprises several parts (94.1 to 94.4) configured to occupy assembled and disassembled states and in that first fiber plies (92) each arranged only opposite one of the first, second, third and fourth inner faces (F1 to F4) are positioned when the parts (94.1 to 94.4) of the mold (94) are in the disassembled state.

7. Method for obtaining a blade grid according to one of the preceding claims, characterized in that the step of assembling first and second tubular preforms (76.1, 76.2) consists of pressing one against the other and connecting the first and second transverse sections (78, 80) of the first and second tubular preforms (76.1, 76.2) of so as to form a blade (64) as well as to align the first longitudinal sides (82) of the first and second tubular preforms (76.1, 76.2) so as to form at least a portion of the first longitudinal wall (62) and the second transverse sides (84) of the first and second tubular preforms (76.1, 76.2) so as to form at least a portion of the first longitudinal wall (62).

8. Method for obtaining a blade grid according to one of the preceding claims, characterized in that at least some blades (64) each comprise a body (68) and a wing (70) substantially perpendicular to the body (68) and in that the first transverse panel (78) extends over at least a portion of a blade (64) at its body (68) and its wing (70), the second transverse panel (80) extending over at least a second portion of a blade (64) at its body (68) and its wing (70), the first and second portions being complementary so that when they are assembled the first transverse panel (78) of a first tubular preform (76.1) and the second transverse panel (80) of a second tubular preform (76.2) form a complete blade (64).

9. Method for obtaining a blade grid according to one of the preceding claims, characterized in that the method for obtaining a blade grid comprises a step of manufacturing at least one longitudinal preform (86) forming a layer of a longitudinal wall (62) as well as a step of assembling the longitudinal preform (86) and the tubular preforms (76.1 to 76.4).

10. Method for obtaining a blade grid according to one of the preceding claims, characterized in that two tubular preforms (76.1 to 76.4) are connected by at least one glue ply (88) and / or at least one fiber ply (90) interposed between the two tubular preforms (76.1 to 76.4).

11. Method for obtaining a blade grid according to one of the preceding claims, characterized in that during the manufacturing step, each tubular preform (76.1 to 76.4) is partially baked or polymerized, a final baking or polymerization phase being carried out subsequently at the latest during the assembly step.

12. Method for obtaining a blade grid according to one of claims 1 to 10, characterized in that during the manufacturing step, each tubular preform (76.1 to 76.4) is completely cooked or polymerized.

13. Blade grid obtained from a production method according to one of the preceding claims.

14. Aircraft comprising at least one blade grid according to the preceding claim.

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