Thrust reverser grid for aircraft nacelle and method for manufacturing such a grid

Abstract

The invention relates to an air deflection grid (5) for an aircraft nacelle thrust reversal system, the grid (5) comprising at least two spars (6) extending along a longitudinal direction (L) of the grid, each spar (6) being connected to at least one adjacent spar by a plurality of blades (7), the grid (5) comprising, at each of its longitudinal ends, a fixing flange extending along a transverse direction (T) of the grid (5) and being integral with end blades connecting the corresponding ends of the spars (6), each spar (6) being formed from at least one fibrous ply (60) comprising: at least a first part (600), or longitudinal part (600), extending along the longitudinal direction (L) of the grid (5);and at least a second part (602), or transverse part (602), extending along the transverse direction (T) of the grid (5), so as to form at least a part of at least one end blade. Figure 4.;

Description

Title of the invention: Thrust reverser grid for an aircraft nacelle and method of manufacturing such a grid Technical field

[0001] The present invention relates to an air deflection grille for a thrust reversal system for an aircraft nacelle, and also relates to a method of manufacturing such a grille. Prior art

[0002] Aircraft are known which are powered by at least one propulsion unit comprising a double-flow turbojet engine housed in a nacelle. Each propulsion unit is attached to the aircraft by a mast generally located under or on a wing, or at the level of the fuselage of the aircraft.

[0003] A nacelle generally has a tubular structure comprising an air inlet upstream of the turbojet engine, a middle section intended to surround a fan of the turbojet engine, a downstream section intended to surround the combustion chamber of the turbojet engine, and is generally terminated by an ejection nozzle whose outlet is located downstream of the turbojet engine.

[0004] The downstream section incorporates in certain cases a thrust reverser system, or thrust reverser. The role of a thrust reverser is to improve the braking capacity of the aircraft by redirecting forward at least part of the thrust generated by the turbojet engine. To this end, the thrust reverser diverts at least part of the cold flow and / or the hot flow generated by the turbojet engine, thereby generating a counter-thrust which is added to the braking of the aircraft wheels. Among the various thrust reverser systems, systems comprising air deflection grilles, also called cascades, are known. Such grille systems comprise one or more movable cowls which can be moved between, on the one hand, a deployed position in which they open a passage in the nacelle intended for the diverted flow, and on the other hand, a retracted position in which they close this passage.When the movable cowl(s) are in the deployed position, they uncover the deflection grilles. In addition, a system of connecting rods connects each movable cowl to blocking doors which deploy inside the secondary vein and block the direct flow outlet. The airflow is then forced to escape from the nacelle by passing through the deflection grilles, which redirect this flow towards the front of the aircraft.

[0005] An air deflection grille comprises rows of deflection vanes, each row of vanes being arranged between two adjacent spars extending in a longitudinal direction of the grille. Within each row, the vanes extend in a direction substantially perpendicular to those of the side members.

[0006] In order to make them lighter than metal grids, the deflection grids are advantageously made of composite materials, for example a material comprising a reinforcement comprising carbon fibers and a matrix comprising a resin. The method of manufacturing grids in composite materials generally involves a step of manually draping numerous plies of dry or pre-impregnated fabrics in a mold, and a cooking step allowing the resin contained or added to the fabrics to be crosslinked.

[0007] [Fig.l] represents a partial view of a known deflection grid, comprising several spars 1 connected to each other by redirection vanes a. In order to be able to be fixed to the structure of the thrust reverser, each grid comprises, at its two longitudinal ends, a fixing flange B. At each flange b, each spar 1 is terminated by a part of generally triangular shape, generally called gusset g. The spars 1 are conventionally made from stacks of layers of woven or unidirectional fibers extending parallel to the surface. The spars 1 may have flat or curved surfaces to also contribute to the air deflection. The flanges b are also made from stacks of layers of woven or unidirectional fibers extending parallel to the surface.

[0008] The spars 1 and the flanges b are connected by layers of woven or non-woven fibers extending in the corners between the spar gusset, the flange surface and the end blades. However, the draping of the gusset areas is very long and proves to be a delicate operation.

[0009] The objective of the present invention is to propose an inverter grid whose manufacture is simplified. Statement of the invention

[0010] To this end, the invention relates to an air deflection grille for an aircraft nacelle thrust reversal system, the grille comprising at least two spars extending in a longitudinal direction of the grille, each spar being connected to at least one adjacent spar by a plurality of vanes, the grille comprising, at each of its longitudinal ends, a fixing flange extending in a transverse direction of the grille and being integral with end vanes connecting the corresponding ends of the spars, each spar being formed from at least one fibrous ply comprising: - at least a first part, or longitudinal part, extending in the longitudinal direction of the grille; and - at least a second part, or transverse part, extending along the transverse direction of the grid, so as to form at least a portion of at least one end vane.

[0011] Thus, by providing that a portion of the material forming the side members is extended in a transverse direction to form at least a portion of each end blade of the grid, the connection between the side members and the fixing flanges is simplified and the draping of these areas is greatly simplified. It is then no longer necessary to provide gussets and the manufacture of a grid according to the invention is simpler, faster and therefore less expensive.

[0012] According to other characteristics of the invention, the grid may comprise one or more of the following optional characteristics considered alone or in all possible combinations.

[0013] According to one characteristic, for each spar, at least one fibrous ply comprises a longitudinal part extending from one longitudinal end to the other of the spar, and comprises, at each end of the spar, a transverse part.

[0014] According to one characteristic, for all or part of the side members, the transverse part of the or each fibrous ply of a side member is formed by folding the fibrous ply in the direction of the same adjacent side member.

[0015] According to one characteristic, the grid comprises at least three side members, and, for the or each side member not being arranged at one of the transverse ends of the grid, this side member or each of these side members comprising at least two fibrous plies, a part of the transverse parts is formed by folding the respective fibrous plies in the direction of a first adjacent side member, the other part of the transverse parts being formed by folding the respective fibrous plies in the direction of a second adjacent side member located opposite the first adjacent side member.

[0016] According to one feature, each fixing flange is formed from fibrous plies, the fibrous plies comprising at least a first portion forming the corresponding fixing flange, and comprising at least a second portion forming at least a portion of each corresponding end blade.

[0017] According to one characteristic, at least a portion of the fibrous plies comprises a second portion arranged behind the transverse portions of the fibrous plies of the corresponding side members for the fixing flange arranged at the front end of the grid, and arranged in front of the transverse portions of the fibrous plies of the corresponding side members for the fixing flange arranged at the rear end of the grid.

[0018] According to one characteristic, the fibrous folds comprise a first part covering the entire width of the grid and comprise a second segmented part, comprising as many segments as the grid has inter-spar spaces.

[0019] According to one characteristic, the fibrous folds have a width adapted to the width of the inter-spar spaces of the grid.

[0020] The invention also relates to a thrust reversal system comprising one or more grids as defined below, as well as a nacelle and a propulsion assembly comprising such a thrust reversal system.

[0021] The invention also relates to a method of manufacturing a thrust reverser grid for an aircraft nacelle as defined above, the method comprising the following steps: - a step of arranging, within a tool, fibrous folds intended to form the grid, the tool comprising mobile cores and mobile elements; - a compression step, during which a force is applied to the mobile elements of the tooling, so as to allow the whole of the mobile elements and the mobile cores of the tooling to come together, and so as to allow the compression of the fibrous folds intended to form the grid; - a consolidation stage, during which the fibrous folds partially or completely harden; and - A step of unmolding the grid thus formed.

[0022] According to an optional characteristic of this manufacturing method, the demolding step includes the elimination of the mobile cores, in particular by total or partial melting. Brief description of the drawings

[0023] [Fig-1] [Fig. 1], described above, is a partial perspective view of a known thrust reverser grid.

[0024] [Fig.2] [Fig.2] is a perspective view of an aircraft propulsion unit, comprising a turbojet engine and a nacelle carrying a grid thrust reverser system, the thrust reverser system being shown in a deployed configuration.

[0025] [Fig.3] [Fig.3] is a perspective view of a deflection grid according to the invention.

[0026] [Fig.4] [Fig.4] is a schematic perspective view of a grid conforming to the invention, in the process of being manufactured.

[0027] [Fig.5] [Fig.5] is a partial schematic perspective view of a grid in accordance with the invention, in the process of being manufactured.

[0028] [Fig.6] [Fig.6] is a schematic perspective view of a grid conforming to the invention, in the process of being manufactured.

[0029] [Fig.7] [Fig.7] is a partial view of the grid of [Fig.6], showing the grid during an optional subsequent manufacturing step.

[0030] [Fig.8] [Fig.8] is a partial view of the grid of [Fig.6], showing the grid during a subsequent manufacturing step.

[0031] [Fig.9] [Fig.9] is a view similar to [Fig.8], showing a variant of the sheave grid of [Fig.8].

[0032] [Fig. 10] [Fig. 10] is a view showing a fibrous fold implemented in the example of [Fig.9].

[0033] [Fig. 11] [Fig. 11] is a schematic view, in section along a plane parallel to the longitudinal and transverse directions, of a tool which can be used for the manufacture of a grid in accordance with the invention, before the implementation of a compression step.

[0034] [Fig. 12] [Fig. 12] is a schematic view of the tooling of [Fig. 11], during the implementation of a compression step.

[0035] [Fig. 13] [Fig. 13] is a schematic view, in section along a plane parallel to the longitudinal and vertical directions, of the tooling of [Fig.11].

[0036] [Fig. 14] [Fig. 14] is a schematic view of the tooling of [Fig. 14], during the implementation of a compression step.

[0037] [Fig. 15] [Fig. 15] is a schematic view of the tooling of [Fig. 11], showing an alternative arrangement of the fiber plies within the tooling.

[0038] [Fig. 16] [Fig. 16] is a diagram illustrating the steps of a method of manufacturing a grid according to the invention. Detailed description

[0039] [Fig. 2] represents an aircraft propulsion unit 1 comprising a dual-flow turbojet 2, and a nacelle 3 carrying a thrust reverser system 4 with deflection grilles. The thrust reverser system 4 comprises in particular a movable external structure 4a, comprising in the example two movable cowls. The external structure 4a is movable between a closed position, in which the thrust reverser system 4 is inactive, and an open position, in which the thrust reverser system 4 is active. In the deployed position, the external structure 4a uncovers a set of deflection grilles 5, through which the redirected air escapes from the nacelle 3.

[0040] The grids 5 are in accordance with the invention, one of these grids being better visible in [Fig. 3]. Each grid 5 comprises at least two longitudinal members 6, elongated in a longitudinal direction L of the grid 5, and deflection vanes 7, 8 (or redirection vanes), each deflection vane 7, 8 joining two adjacent longitudinal members 6. The vanes 7, 8 extend between two adjacent longitudinal members 6, in a direction substantially perpendicular to the longitudinal direction of the grid 5, that is to say in a direction substantially parallel to the transverse direction T of the grid 5. The vanes 7, 8 comprise intermediate vanes 7, that is to say vanes not forming not one of the longitudinal ends of the grid 5, and end vanes 8, forming one of the longitudinal ends of the grid 5. At each longitudinal end, the grid 5 comprises a fixing flange 9, i.e. a front fixing flange 9 and a rear fixing flange 9.

[0041] The grids 5 are made of a composite material, for example a material comprising a reinforcement comprising fibers and a matrix comprising a resin. The reinforcement may for example comprise carbon, glass, aramid, nylon, polyester, linen, etc. fibers. The matrix may for example comprise a thermosetting or thermoplastic polymer resin.

[0042] Figures 4 and 5 illustrate, schematically, a grid 5 according to the invention, during manufacture. More precisely, [Fig.4] and 5 represent the grid 5 during a draping step, that is to say a step of arranging in a mold (not shown) the layers of fibers (or fibrous plies) necessary for the constitution of the final part. By fibrous ply, is meant a layer of fibers, in particular a layer of low thickness, comprising exclusively or essentially fibers oriented in a direction parallel to a plane in which the layer of fibers is arranged.Such a layer of fibers may be of the continuous fiber type, being formed by a weave of warp fibers and weft fibers or by a sheet of unidirectional fibers, or of the discontinuous fiber type, being formed for example by a mat or by a material of the “DLF” type (acronym corresponding to the English name “Discontinuons Long Fiber”, meaning “long discontinuous fiber”). In [Fig. 4], all of the fiber plies intended to constitute the spars 6 and the intermediate blades 7 are arranged. In [Fig. 5], on which only a front end of the grid is visible, all of the fiber plies intended to constitute the end blades 8 and the flanges 9 are arranged. Thus, [Fig. 5] partially represents a grid 5 at the end of the draping step.

[0043] As can be seen more particularly in [Fig. 4], each intermediate blade 7 is formed by one or more fibrous plies 70, and each spar 6 is formed by one or more fibrous plies 60. For each spar 6, at least one fibrous ply 60 comprises at least one first portion 600, or longitudinal portion 600, extending in the longitudinal direction L of the grid 5, and at least one second portion 602, or transverse portion 602, extending in the transverse direction T of the grid 5, so as to form at least one portion of at least one end blade 8. In the example of the figures, each fibrous ply 60 comprises at least one longitudinal portion 600 and at least one transverse portion 602.

[0044] As visible in [Fig.4], each fibrous ply 60 may comprise a longitudinal portion 600 extending from one end to the other of the corresponding spar 6 (and therefore from an end blade 8 located at the front end of the grid to an end blade 8 located at the rear end of the grid), and comprising, at each longitudinal end of the spar 6, a transverse part 602. In such a configuration, each fibrous ply 60 comprises a longitudinal part forming at least one part of the spar and two transverse parts 602, each transverse part 602 forming at least one part of at least one respective end blade 8.

[0045] By providing that each fibrous ply 60 comprises at least one longitudinal portion 600 and at least one transverse portion 602, it is ensured that at least one portion of the fibers forming the spars 6 extends, continuously, from the longitudinal portion 600 to the transverse portion 602. Thus, fibers extend, continuously, from the spars 6 at least to the end blades 8, which makes it possible to effectively transfer the forces coming from the spars 6 to the end blades 8 and then to the fixing flanges 9. The fibrous plies 60 may further comprise fibrous plies comprising only a longitudinal portion, and not comprising a transverse portion.

[0046] In [Fig. 5], fibrous plies 90, 91 intended to form one of the fixing flanges 9 have been arranged. In the example of [Fig. 5], each fibrous ply 90, 91 comprises a first part 900, 910 intended to form a part of the fixing flange 9 and a second part 902, 912, forming an angle with the first part 900, 910, and intended to form at least a part of each corresponding end blade 8. Thus, the set of first parts 900, 910 of the fibrous plies 90, 91 forms the fixing flange 9, and the second parts 902, 912 of the fibrous plies 90, 91 form, with the transverse parts 602 of the fibrous plies 60 of the side members 6, the end blades 8. As visible in [Fig.5], it may be provided that at least a first portion of the fibrous folds 90 is arranged such that the second portions 902 of these fibrous folds 90 are located behind the transverse portions 602 for the front fixing flange 9 (and in front of the corresponding transverse portions 602 for the rear fixing flange 9), and that a second portion of the fibrous folds 91 is arranged such that the second portions 912 of these fibrous folds 91 are located in front of the transverse portions 602 for the front fixing flange 9 (and behind the corresponding transverse portions 602 for the rear fixing flange 9). It may also be provided that all of the second portions 902, 912 are located on the same side of the transverse portions 602 of the fibrous folds 60.

[0047] In the examples of figures 4 and 5, for each intermediate spar 6 (that is to say for each spar not located at one of the transverse ends of the grid), several fibrous folds 60 are provided. Thus, for each intermediate spar, several transverse parts 602 are provided. A part of the transverse parts 602 of the fibrous folds 60 is formed by folding a part of the fibrous folds 60 in a first direction, more precisely in the direction of one of the spars adjacent, the remaining portion of the transverse portions 602 being formed by folding the remaining fibrous plies 60 in a second direction, more precisely in the direction of the opposite adjacent spar. Thus, at each longitudinal end of the grid 5, the fibrous plies 60 of an intermediate spar have a “T” shape.

[0048] In a variant shown in [Fig. 6], for each spar 6, at a given longitudinal end of this spar 6, the transverse parts 602 of the fibrous plies 60 are formed by folding the fibrous plies 60 in the same direction, more precisely in the direction of the same adjacent spar (i.e. in a single direction for each spar, this direction not necessarily being the same from one spar to another). Thus, at each longitudinal end, the fibrous ply or plies 60 of a spar 6 have an “L” shape.

[0049] Whatever the configuration of the transverse portions 602 of the fibrous plies 60 (in an “L” or “T” shape), it will be possible to provide an overlap between the transverse portions 602 of the fibrous plies 60 of two adjacent spars, or even an overlap between the transverse portions 602 of the fibrous plies of at least three neighboring spars. Thus, in the example of [Fig. 4], a partial overlap is provided between the transverse portions 602 belonging respectively to fibrous plies 60 of adjacent spars 6, the overlap extending only between the two adjacent spars. In the example of [Fig. 5], no overlap is provided, and the ends of the transverse portions 602 belonging respectively to fibrous plies 60 of adjacent spars are positioned edge to edge.As shown in Figures 6, 7 and 8, the transverse portions 602 of the fibrous plies 60 of some of the spars extend, in the transverse direction, beyond those of the corresponding adjacent spar.

[0050] As shown in [Fig.7], whether or not an overlap of the transverse parts 602 is provided (or whether it is provided only for certain side members), one or more end folds 80 may be provided, extending continuously from one transverse end to the other of the grid, and thus forming, with all of the transverse parts 602, at least a part of each end blade 8.

[0051] Figures 5 and 8 to 10 show different ways of arranging the fibrous folds 90, 91 intended to form the fixing flanges 9.

[0052] As mentioned above, a portion of the fibrous plies 90, 91 intended to form the fixing flanges 9 may extend behind (for the front fixing flange, and in front for the rear fixing flange 9) the transverse portions 602 of the fibrous plies 60 forming the side members 6. Such a configuration makes it possible to obtain good mechanical strength of the grid 5 in the event of traction on the fixing flange 9. As visible in [Fig. 8], it may be provided that the fibrous plies 90, the second portions 902 of which are located behind the transverse portions 602 of the fibrous plies 60 of the side members 6 are independent along the transverse direction. In other words terms, each of these fibrous plies 91 has a width less than the width of the grid (i.e. its dimension along the transverse direction), and, more precisely, has a width allowing each second part 902 to be arranged between two adjacent longitudinal members 6. Thus, as visible in [Fig. 8], it is necessary to provide at least one fibrous ply 90 per inter-spar space. It can be provided that all of the fibrous plies visible in [Fig. 8] are sufficient to produce the end vanes 8 and the fixing flanges 9. However, it may be possible to provide for the addition of one or more end plies 80 similar to those shown in [Fig. 7], and / or one or more fibrous plies 91 similar to those shown in [Fig. 5], and / or one or more plies extending so as to cover all of the first parts 900 of the fibrous plies 90 (not shown).

[0053] Alternatively, as visible in Figures 9 and 10, it may be provided that the fibrous plies 90 whose second parts 902 are located behind (for the front fixing flange) the transverse parts 602 of the fibrous plies 60 of the side members 6 cover the entire width of the grid along the transverse direction. As shown in [Fig. 10], each fibrous ply 90 may then comprise a first continuous part 900 and a second segmented part 902, the second part 902 comprising as many segments as there are inter-side member spaces.

[0054] The grid 5 according to the invention may advantageously be produced using tools such as those described in international application No. WO 2021 / 123628 A1.

[0055] Such a tool 10 is shown in Figures 11 to 15, Figures 11 and 12 showing a top sectional view of the tool 10, respectively before and after implementation of a compression step. Figures 13 and 14 are side sectional views of the tooling corresponding to Figures 11 and 12 respectively. The tooling 10 comprises a frame 11 comprising fixed elements 110 and mobile elements 112, as well as mobile cores of two types, blade cores 12 and flange cores 13. As visible in Figures 12 and 14, the mobile elements 112 of the tooling make it possible to ensure the compression of all the mobile elements of the mold and therefore of all the fiber plies arranged in the tooling, by applying a force F to the mobile elements 112 of the frame 11. Such a tooling makes it possible to produce, in a molding step, the entirety of a deflection grid 5.Figures 11 and 12 show the arrangement of the fibrous folds 60 in an “L” shape, while [Fig. 15] shows the arrangement of the fibrous folds 60 in a “T” shape.

[0056] Furthermore, as can be seen in Figures 13 and 14, it can be provided that the fibrous folds 90 forming each fixing flange 9 of the deflection grid are arranged in an “L” shape (left flange in Figures 13 and 14), or are arranged in a “T” shape (right flange in Figures 13 and 14). To produce the “T” shaped flange, the fibrous folds 60 of spars can be divided at the leg of the “T” into two superimposed transverse parts 602, one being positioned under the leg of the “T” formed by the fixing flange, the other being positioned above the leg of the “T”). In this configuration, the fibrous folds 90 forming the end flange 9 in the shape of a “T” are arranged so that a part of the second parts 902 extends towards the lower end of the grid (i.e. towards the leading edge of the end blades 8) and the other part of the second parts 902 extends in the opposite direction, towards an upper end of the grid (i.e. towards the trailing edge of the end blades 8). It should be noted that all the embodiments described in relation to figures 4 to 10 can be implemented within the framework of the production of a “T” shaped fixing flange.

[0057] [Fig. 16] represents the steps of implementing a method 200 for manufacturing a grid 5, using tooling 10 similar to that of FIGS. 11 to 15.

[0058] This method 200 comprises a step 202 of arranging fibrous plies 60, 70, 90, 91 intended to form the grid 5, during which the fibrous plies intended to form the side members 6, the fibrous plies 70 intended to form the blades 7 of the grid, and the plies 90, 91 intended to form the fixing flanges 9 of the grid 5 are arranged within the tooling.

[0059] The method 200 comprises a compression step 204, during which a force F is applied to the mobile elements 112 of the frame 11, so as to allow the bringing together of all the mobile elements of the tool 10, including the mobile cores 12, 13, and thus the compression of the fibrous folds intended to form the grid 5. The compression step 204 is carried out by means of compression devices such as jacks (not shown).

[0060] The method 200 comprises a consolidation step 206, during which the fibrous folds intended to form the grid 5 partially or completely harden.

[0061] The method 200 comprises a step 208 of demolding the grid thus formed.

[0062] The demolding step 208 may comprise the elimination of the blade cores 12, in particular by total or partial melting.

[0063] Preferably, the composite material constituting the various elements to be molded is a pre-impregnated composite material. It comprises, for example, a thermosetting or thermoplastic resin and fibers, such as carbon fibers. The resin of the pre-impregnated composite material may be raw, or partially crosslinked.

[0064] The pre-impregnated composite material advantageously comprises continuous fibers and / or discontinuous fibers, such as carbon, glass, aramid, nylon, polyester, linen fibers, etc.

[0065] During each compression and / or consolidation step, an optional heating step can be implemented, in particular in order to soften the resin of the material. prepreg composites.

[0066] The consolidation or hardening of the final part is obtained by maintaining the temperature and then cooling according to the values ​​and durations adapted to the resin used. A thrust reverser grid 5 for the nacelle is then obtained by demolding the consolidated composite material and extracting the tooling elements. Finishing and machining operations can also be carried out.

[0067] In the case where the movable molding cores are partially or entirely made of a low-melting point metal alloy, a heating step at a temperature higher than the melting temperature of the alloy is carried out after consolidation of the resin.

[0068] In one embodiment, the heating step is carried out where appropriate after the cooling mentioned above.

Claims

Claims

1. Air deflection grille (5) for an aircraft nacelle thrust reversal system, the grille (5) comprising at least two spars (6) extending in a longitudinal direction (L) of the grille, each spar (6) being connected to at least one adjacent spar by a plurality of vanes (7, 8), the grille (5) comprising, at each of its longitudinal ends, a fixing flange (9) extending in a transverse direction (T) of the grille (5) and being integral with end vanes (8) connecting the corresponding ends of the spars (6), each spar (6) being formed from at least one fibrous ply (60) comprising: - at least a first part (600), or longitudinal part (600), extending in the longitudinal direction (L) of the grille (5);and - at least one second part (602), or transverse part (602), extending in the transverse direction (T) of the grid (5), so as to form at least one part of at least one end blade (8).;

2. Air deflection grille (5) according to the preceding claim, in which, for each spar (6), at least one fibrous ply (60) comprises a longitudinal part (600) extending from one longitudinal end to the other of the spar (6), and comprises, at each end of the spar (6), a transverse part (602).

3. Air deflection grille (5) according to one of the preceding claims, in which, for all or part of the side members (6), the transverse part (602) of the or each fibrous ply (60) of a side member (6) is formed by folding the fibrous ply (60) in the direction of the same adjacent side member.

4. Air deflection grille (5) according to one of the preceding claims, the grille comprising at least three longitudinal members (6), and in which, for the or each longitudinal member (6) not being arranged at one of the transverse ends of the grille (5), this longitudinal member (6) or each of these longitudinal members (6) comprising at least two fibrous plies (60), a part of the transverse parts (602) is formed by folding the respective fibrous ply or plies (60) in the direction of a first adjacent longitudinal member, the other part of the transverse portions (602) being formed by folding the respective one or more fibrous plies (60) towards a second adjacent spar (6) located opposite the first adjacent spar (6).

5. A deflection grid (5) according to one of the preceding claims, wherein each fixing flange (9) is formed from fibrous plies (90, 91), the fibrous plies (90, 91) comprising at least a first portion (900, 910) forming the corresponding fixing flange (9), and comprising at least a second portion (902, 912) forming at least a portion of each corresponding end vane (8).

6. Deflection grid (5) according to the preceding claim, in which at least a portion of the fibrous folds (90, 91) comprises a second portion (902) arranged behind the transverse portions (602) of the fibrous folds (60) of the corresponding side members (6) for the fixing flange arranged at the front end of the grid (5), and arranged in front of the transverse portions (602) of the fibrous folds (60) of the corresponding side members (6) for the fixing flange arranged at the rear end of the grid (5).

7. Deflection grid (5) according to the preceding claim, in which the fibrous folds (90) comprise a first part (900) covering the entire width of the grid (5) and comprise a second segmented part (902), comprising as many segments as the grid has inter-spar spaces.

8. Deflection grid (5) according to claim 6, in which the fibrous folds (90) have a width adapted to the width of the inter-spar spaces of the grid (5).

9. Method (200) for manufacturing a thrust reverser grid (5) for an aircraft nacelle according to any one of the preceding claims, the method comprising the following steps: - a step (202) of arranging, within a tool (10), fibrous plies (60, 70, 80, 90, 91) intended to form the grid (5), the tool comprising mobile cores (12, 13) and mobile elements (112); - a compression step (204), during which a force (F) is applied to the mobile elements (112) of the tool, so as to allow the assembly of mobile elements (12) and mobile cores (12, 13) of the tool (10) to be brought together, and so as to allow the com- pressure of the fibrous folds (60, 70, 80, 90, 91) intended to form the grid (5); - a consolidation step (206), during which the fibrous folds partially or totally harden; and - a step (208) of demolding the grid (5) thus formed.

10. Method (200) according to claim 9, in which the demolding step (208) comprises the elimination of the mobile cores (12, 13), in particular by total or partial melting.

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