Method for obtaining a blade grid for an aircraft thrust reverser device from tubular preforms, blade grid obtained by this method
The use of tubular preforms and assembly techniques for blade grids addresses the mass and energy consumption issues of traditional methods, enabling the production of blades with enhanced mechanical properties and reduced number of cells.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2024-03-15
- Publication Date
- 2026-03-13
AI Technical Summary
Existing methods for manufacturing blade grids for aircraft thrust reverser devices result in structures with a large number of cells and a relatively high mass, leading to increased onboard mass and energy consumption, and are not suitable for blades with significant depth due to the complexity of core expansion and extraction.
A method involving the use of tubular preforms, where each preform is manufactured using simple tooling to ensure structural integrity, and assembled to form blades with a significant depth, utilizing compression and polymerization phases to achieve excellent mechanical properties.
The method allows for the production of blade grids with reduced mass and improved mechanical properties by using tubular preforms that can be efficiently compressed and assembled, resulting in blades with a larger depth without the complexity of traditional core expansion.
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Abstract
Description
Title of the invention: Method for obtaining a blade grid for an aircraft thrust reverser device from tubular preforms, blade grid obtained by this method
[0001] The present application relates to a method of obtaining a blade grid for an aircraft thrust reversing 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 them by masts 16. Each propulsion unit 12 comprises a motor 18 positioned inside a nacelle 20. The motor 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 notions front / upstream and rear / downstream refer to the direction of flow of an airflow 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, together with the motor 18, defines an annular duct 22 through which a secondary airflow passes. The nacelle 20 comprises an upstream section 24 called the air inlet, a middle section 26 in which the blower of the motor 18 is positioned, and a downstream section 28 which has a trailing edge 30.
[0005] The nacelle 20 includes a thrust reversing device 34 positioned at the downstream section 28 and configured to occupy an activated state in which it diverts at least part of the secondary airflow circulating in the annular duct 22 to the outside and upstream of the nacelle 20 and an inactivated state in which it does not divert the secondary airflow circulating in the annular duct 22.
[0006] The thrust reversing device 34 includes at least one movable part 36 enabling the generation of at least one lateral opening 38 (visible in [Fig.2]) passing through the nacelle 20.
[0007] The thrust reversing device 34 includes a deflection system 40 configured to occupy a retracted position when the thrust reversing device 34 is in the inactivated state, in which the deflection system 40 does not interfere with the secondary airflow, and a deployed position when the thrust reversing 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 reversing device 34 also includes a guidance system 42 configured to guide the airflow deflected by the deflection system 40. According to one embodiment, the guidance system 42 includes several blade grids 44 called cascades and positioned at each lateral opening 38.
[0009] According to an embodiment shown in Figures 4 and 5, each blade grid 44 comprises longitudinal walls 46 positioned in approximately longitudinal planes and blades 48 positioned in approximately transverse planes. The longitudinal walls 46 and the blades 48 define cells 50.
[0010] The blades 48 have a profile to deflect upstream the outgoing airflow through 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 shallow depth P of the blades 48, the blade grids 44 have a large number of cells 50 and therefore a relatively large mass, which is penalizing in terms of onboard 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 method, a process 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 flat. The second preforms 48' have an H-shaped cross-section provided with first and second wings 48.1', 48.2' at each end, intended to be pressed against the first preforms 46'.
[0015] The process for obtaining a blade grid 44 comprises, for each row of blades, a step of positioning by alternating second preforms 48' and cores 52 between two first preforms 46' that are 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 process includes a consolidation or polymerization step, to link the first and second preforms 46', 48' together, during which the whole is compressed and subjected to a temperature rise.
[0016] The temperature increase causes the cores 52 to expand, compressing the second preforms 48'. After the consolidation or polymerization step, the resulting blade grid 44 and the cores 52 are cooled, causing the cores 52 to contract. The production process then includes 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 resulting blade grid 44.
[0018] This manufacturing process, suitable for shallow blades, is not suitable for blades with a significant depth, as the cores do not expand sufficiently to compress the preforms. Furthermore, the larger the core, the more complex it is to control its deformation. For blades with a significant depth, it is necessary to design relatively complex, spool-shaped cores that are difficult, if not 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 reversal device, said blade grid comprising at least first and second longitudinal walls and 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 method of obtaining it comprises: a. a manufacturing step of at least the first and second tubular preforms, each comprising a first transverse face forming at least one layer of a first blade, a second transverse face forming at least one layer of a second blade, a first longitudinal face forming at least one layer of a first longitudinal wall, and a second longitudinal face forming at least one layer of a second longitudinal wall; the first and second transverse faces and the first and second longitudinal faces forming a single piece and delimiting a cell, b. an assembly step of the first and second tubular preforms consisting of joining: i. the first and second transverse sections of the first and second tubular preforms so as to form a common blade, and / or ii. the first and second longitudinal sections 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 that guarantees the structural integrity of said preforms. This makes it possible to obtain, after an assembly step of said preforms, a blade grid that exhibits excellent mechanical properties and blades with, for at least some, a relatively significant depth.
[0023] According to another feature, the manufacturing step includes, 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 feature, prior to the compression phase, the manufacturing step includes, for at least one tubular preform, a draping phase during which fiber folds are positioned on or against at least one mold which has first, second, third and fourth inner faces shaped respectively as the first transverse and longitudinal panels as well as the second transverse and longitudinal panels.
[0025] According to another feature, 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 faces of a tubular preform positioned in the mold and expanding the expandable element so as to compress said tubular preform.
[0026] According to another feature, the fiber plies are positioned on the first, second, third and fourth inner faces when the mold has a tubular shape, alternating first fiber plies arranged only with respect to one of the first, second, third and fourth inner faces and second corner fiber plies arranged straddling two inner faces among the first, second, third and fourth inner faces.
[0027] According to another feature, the mold comprises several parts configured to occupy assembled and disassembled states. In addition, first plies of fibers, each arranged only with respect to one of the first, second, third, and fourth inner faces, are positioned when the mold parts are in the disassembled state.
[0028] According to another feature, the assembly step of the first and second tubular preforms consists of pressing the first and second transverse faces of the first and second tubular preforms together and connecting them so as to form a blade, as well as aligning the first longitudinal faces of the first and second tubular preforms so as to form at least part of the first longitudinal wall and the second transverse faces of the first and second tubular preforms so as to form at least part of the first longitudinal wall.
[0029] According to another feature, at least some blades each comprise a body and a wing substantially perpendicular to the body. In addition, the first transverse face extends over at least one part of a blade at the level of its body and its wing, the second transverse face extending over at least a second part of a blade at the level of its body and its wing, the first and second parts being complementary such that when assembled the first transverse face of a first tubular preform and the second transverse face of a second tubular preform form a complete blade.
[0030] According to another feature, the method for obtaining a blade grid includes a manufacturing step of 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 feature, two tubular preforms are connected by at least one layer of glue and / or at least one layer of fibers intercalated between the two tubular preforms.
[0032] According to another feature, during the manufacturing step, each tubular preform is partially baked or polymerized, with a final baking or polymerization phase being carried out later, at the latest during the assembly step.
[0033] According to another feature, during the manufacturing step, each tubular preform is fully baked or polymerized.
[0034] The invention also relates to a blade grid obtained from a production process according to one of the preceding characteristics and to an aircraft comprising at least one such blade grid.
[0035] Other features and advantages will become apparent from the following description of the invention, given by way of example only, with reference to the accompanying 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 cross-section of a propulsion assembly equipped with a thrust reversing device in the inactivated state illustrating a prior art embodiment,
[0039] [Fig.4] is a perspective view of a blade grid illustrating a method of rea- lization of prior art,
[0040] [Fig.5] is a longitudinal section along the PV plane of the blade grid visible on the [Fig.4],
[0041] [Fig.6] is a schematic representation of a step in the installation of walls longitudinal, blade and core designs illustrating a method of realization of the earlier art,
[0042] [Fig.7] is a top view of a blade grid during a consolidation step or polymerization illustrating a method of embodiment of the prior art,
[0043] [Fig.8] is a perspective view of a blade grid illustrating a method of publication of the invention,
[0044] [Fig.9] is a longitudinal section along the P-IX plane of the blade grid visible on the [Fig.8],
[0045] [Fig. 10] is a perspective view of a turbine blade illustrating one embodiment of the invention,
[0046] [Fig. 11] is a longitudinal section of a tool and a tubular preform illustrating one embodiment of the invention,
[0047] [Fig. 12] is a cross-section along a median surface of a tool and a tubular preform illustrating an embodiment of the invention
[0048] [Fig. 13] is a cross-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 one 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 cross-section along a median surface of an assembly of several tubular preforms illustrating one embodiment of the invention,
[0052] [Fig. 17] is a longitudinal section of part of an assembly of tubular preforms illustrating one embodiment of the invention,
[0053] [Fig. 18] is a perspective view of part of a blade grid before an assembly step illustrating one embodiment of the invention,
[0054] [Fig. 19] is a schematic cross-section along a median surface of an assembly of several tubular preforms illustrating one embodiment of the invention,
[0055] [Fig.20] is a schematic representation of a blade grid with different moments of an assembly step illustrating one embodiment of the invention.
[0056] According to one application, an aircraft includes at least one thrust reversing device which includes 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 the 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 alveoli 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. In one arrangement, the inner edges 62.1, 64.1 of the longitudinal walls 62, 62' and of the blades 64, 64' are positioned at a first surface forming an inner surface F60 of the blade grid 60, while the outer edges 62.2, 64.2 of the longitudinal walls 62, 62' and of the blades 64, 64' are positioned at a second surface forming an outer surface F60' of the blade grid 60. In another 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 substantially parallel to each other and oriented along a transverse direction substantially perpendicular to the longitudinal direction.
[0061] According to one configuration, each blade 64, 64' has a substantially constant cross-section in the transverse direction. The blades 64, 64' may have identical cross-sections. Alternatively, as illustrated in [Fig. 9], the blades 64, 64' have different cross-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 extending between a first edge 68.1, corresponding to the inner edge 64.1 of the blade 64, and a second edge 68.2, and a wing 70 situated in the extension of the body 68 extending between a first edge 70.1, corresponding to the outer edge 64.2 of the blade 64, and a second edge 70.2 integral with 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 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 for the proper compression of a preform intended to form a blade using cores simple according to a process of the prior art 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' and four blades 64, 64' per row of blades, the longitudinal walls 62 and the blades delimiting eight cells 66.
[0067] Given 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 one row of blades 72.
[0069] Regardless of the embodiment, the blade grid 60 comprises end longitudinal walls corresponding to the most widely 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 Figures 14 and 15, each end plate 74 is a substantially rectangular strip of material having long sides substantially parallel to the transverse direction. At least one end plate 74 comprises at least one through-hole 74.1 configured for attaching the blade grid 60 to an aircraft structure.
[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 for obtaining a blade grid 60 comprises: a. a manufacturing step of at least the first and second tubular preforms 76.1, 76.2 each comprising a first transverse face 78 forming at least one layer of a first blade 64, a second transverse face 80 forming at least one layer of a second blade 64', a first longitudinal face 82 forming at least one layer of a first longitudinal wall 62 and a second longitudinal face 84 forming at least one layer of a second longitudinal wall 62'; the first and second transverse faces 78, 80 and the first and second longitudinal faces 82, 84 forming a single piece and delimiting a cell 66, b. an assembly step of the first and second tubular preforms 76.1, 76.2 consisting of pressing them together and joining: i. 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 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 assembly step of the first and second tubular preforms 76.1, 76.2 consists of pressing the first and second transverse faces 78, 80 of the first and second tubular preforms 76.1, 76.2 together and connecting them so as to form a blade 64 and aligning the first longitudinal faces 82 of the first and second tubular preforms 76.1 to 76.2 so as to form at least part of the first longitudinal wall 62 and the second transverse faces 84 of the first and second tubular preforms 76.1 to 76.2 so as to form at least part of the first longitudinal wall 62.
[0074] According to one configuration, the first and second longitudinal panels 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 panel 82 extends over a first part of a longitudinal wall 62 and the second longitudinal panel 84 extends over a second part of a longitudinal wall 62, the first and second parts being complementary so that the first longitudinal panel 82 of a first tubular preform 76.1 and the second longitudinal panel 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 panels 78, 80 extends at the level of the body 68 and the wing 70 of a blade 64. Thus, as illustrated in Figures 11 and 17, the first transverse panel 78 forms a first part of the body 68 and the wing 70 of a blade 64 and the second transverse panel 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 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.
[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] Regardless of the configuration, the first transverse panel 78 extends over at least one part of a blade 64 and the second transverse panel 80 extends over at least a second part of a blade 64 complementary to the first part so that when 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 method, 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 Figures 14 and 15.
[0079] According to a second operating method as illustrated in [Fig.20], when a blade grid 60 comprises several rows of blades, the assembly step includes a first assembly phase of each row consisting of connecting the tubular preforms 76.1 to 76.4 so as to form the rows of blades independently of each other, then a second assembly phase of the different rows of blades consisting of connecting the rows of blades together.
[0080] According to an embodiment visible in figures 14 and 18, the process for obtaining a blade grid includes a manufacturing step of 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 method visible in Figures 14 to 16, a longitudinal preform 86 is interposed between the first longitudinal faces 82 of a first row of tubular preforms and the second longitudinal faces 84 of a second row of tubular preforms. According to this first operating method, a longitudinal wall 62 located between two rows of blades comprises the first longitudinal faces 82 of the first row of tubular preforms, the longitudinal preform 86, and the second longitudinal faces 84 of the second row of tubular preforms.
[0082] According to a second operating method shown 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 method, a longitudinal wall 62 comprises a longitudinal preform 86, 86' and the first or second longitudinal faces 82, 84 of a row of tubular preforms.
[0083] According to this second operating method, 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 faces 82 of the first row of tubular preforms, two longitudinal preforms 86, 86' as well as the second longitudinal faces 84 of the second row of tubular preforms.
[0084] When the blade grid 60 includes at least one end plate 74, 74', the method for obtaining a blade grid includes a manufacturing step for each end plate 74, 74' and an assembly step for 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 thermoset resin matrix hardenable or thermoplastic. Each end plate 74, 74' is made of a composite material and comprises fibers embedded in a thermosetting or thermoplastic resin matrix. Depending on the 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 and the possible longitudinal preforms 86, 86' and end plates 74, 74' each comprise a thermosetting resin matrix, each assembly step consists of joining the tubular preforms 76.1 to 76.4 and the possible longitudinal preforms 86, 86' and end plates 74, 74' by bonding or co-curing.
[0087] When the tubular preforms 76.1 to 76.4 and the possible longitudinal preforms 86, 86' and end plates 74, 74' each comprise a thermoplastic resin matrix, each assembly step consists of joining the tubular preforms 76.1 to 76.4 and the possible longitudinal preforms 86, 86' and end plates 74, 74' by bonding, 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 intervening 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 fiber ply 90 (resin-impregnated or unimpregnated) intercalated between the two tubular preforms 76.1, 76.2. Glue plies 88, 88' can be intercalated between the fiber ply 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' can be intercalated 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 asperities present on the surfaces of the tubular and long-lined 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. These can be combined and possibly other assembly methods can be implemented.
[0094] According to a first method, each tubular or longitudinal preform 76.1 to 76.4, 86, 86' is partially baked or polymerized during the manufacturing step which includes a partial baking or polymerization phase, a final baking or polymerization phase being carried out later at the latest during the assembly step.
[0095] According to a second method, each tubular or longitudinal preform 76.1 to 76.4, 86, 86' is fully baked or polymerized during the manufacturing step which includes 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 manufacturing step of 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 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.
[0097] According to one embodiment, the two phases of compression and curing or polymerization are simultaneous. According to another embodiment, the curing or polymerization phase is completed before the end of the compression phase. According to this embodiment, the tubular preform 76.1 to 76.4 is compressed until at least partial curing 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 to a pressure of between 2 and 7 bar and heated to a temperature of approximately 180°C. Of course, the invention is not limited to these pressures and temperatures. These 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 baked or polymerized to maintain stable geometry and dimensions.
[0100] These compression and baking or at least partial polymerization phases ensure the structural integrity of the blade grid 60.
[0101] Prior to the compression phase, the manufacturing step of the tubular preforms 76.1 to 76.4 includes, 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 inner faces Fl to F4 shaped respectively as 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 Figures 13, configured to occupy assembled and disassembled states. This solution facilitates demolding. In one configuration, the mold 94 comprises four parts 94.1 to 94.4, each having one of the first, second, third, and fourth inner faces Fl to F4.
[0104] According to a first operating method visible in [Fig. 12], the fiber folds 92 are positioned on the first, second, third and fourth inner faces Fl to F4 when the mold 94 is assembled and has a tubular shape. According to this operating procedure, first plies of fibers 92, each positioned only with respect to one of the first, second, third and fourth inner faces Fl to F4, are positioned alternately with second plies of angled fibers 92' arranged straddling two inner faces among the first, second, third and fourth inner faces Fl to F4.
[0105] According to a second operating method shown in [Fig. 13], the first fiber plies 92, each positioned only with respect to one of the first, second, third, and fourth inner faces Fl to F4, are positioned when the parts 94.1 to 94.4 of the mold 94 are in the disassembled state. This solution simplifies the placement of the first fiber plies 92. According to this second operating method, the second corner fiber plies 92' are not placed alternately with the first fiber plies 92 and are added once the latter have been positioned.
[0106] Of course, the invention is not limited to these operating methods for the placement of 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 faces 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 tooling for manufacturing tubular preforms 76.1 to 76.4 includes, 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 inner faces Fl 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, from a simple tooling, to efficiently compress each tubular preform 76.1 to 76.4 during the cooking or at least partial polymerization phase, which ensures a structural integrity of each tubular preform 76.1 to 76.4.
[0109] In addition, as illustrated in [Fig. 11], the manufacturing tooling may include a base 98 and a cover 100 positioned at the ends of the mold 94 so as to delimit with the latter a cavity.
[0110] Regardless of the embodiment and 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 one using relatively simple tooling while guaranteeing the structural integrity of each one, which allows, after assembly of said preforms, to obtain a grid of blades which exhibits excellent mechanical properties and blades with, for at least some, a relatively large depth.
Claims
Demands
1. A 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') and blades (64, 64') positioned between said first and second longitudinal walls (62, 62') and connected to them, the longitudinal walls (62, 62') and the blades (64, 64') defining cells (66); characterized in that the method of obtaining comprises: a. a manufacturing step of at least the first and second tubular preforms (76.1, 76.2) each comprising a first transverse face (78) forming at least one layer of a first blade (64), a second transverse face (80) forming at least one layer of a second blade (64'), a first longitudinal face (82) forming at least one layer of a first longitudinal wall (62) and a second longitudinal face (84) forming at least one layer of a second longitudinal wall (62'); the first and second transverse faces (78, 80) and the first and second longitudinal faces (82, 84) forming a single piece and delimiting a cell (66), b. an assembly step of the first and second tubular preforms (76.1, 76.2) consisting of joining: c. the first and second transverse faces (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 faces (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. A 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 curing or polymerization phase during which said tubular preform (76.1 to 76.4) is compressed and at least partially cured or polymerized.
3. A method for obtaining a blade grid according to the preceding claim, characterized in that, prior to the compression phase, the manufacturing step includes, 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 as the first transverse and longitudinal panels (78, 82) and the second transverse and longitudinal panels (80, 84).
4. A 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 faces (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 of obtaining a blade grid according to any one of claims 3 to 4, characterized in that the fiber plies (92) are positioned on the first, second, third and fourth inner faces (Fl to F4) when the mold (94) has a tubular shape, alternating first fiber plies (92) each arranged only with respect to one of the first, second, third and fourth inner faces (Fl to F4) and second angled fiber plies (92') arranged straddling two inner faces among the first, second, third and fourth inner faces (Fl to F4).
6. A method for obtaining a blade grid according to any 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 plies of fibers (92) each disposed only with respect to 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. A method for obtaining a blade grid according to any one of the preceding claims, characterized in that the step of assembling the first and second tubular preforms (76.1, 76.2) consists of pressing the first and second transverse faces (78, 80) of the first and second tubular preforms (76.1, 76.2) together and connecting them. so as to form a blade (64) and to align the first longitudinal faces (82) of the first and second tubular preforms (76.1, 76.2) so as to form at least part of the first longitudinal wall (62) and the second transverse faces (84) of the first and second tubular preforms (76.1, 76.2) so as to form at least part of the first longitudinal wall (62).
8. A method for obtaining a blade grid according to any 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 face (78) extends over at least a part of a blade (64) at the level of its body (68) and its wing (70), the second transverse face (80) extending over at least a second part of a blade (64) at the level of its body (68) and its wing (70), the first and second parts being complementary so that when assembled the first transverse face (78) of a first tubular preform (76.1) and the second transverse face (80) of a second tubular preform (76.2) form a complete blade (64).
9. A method for obtaining a blade grid according to any one of the preceding claims, characterized in that the method for obtaining a blade grid comprises a manufacturing step of 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. A method for obtaining a blade grid according to any one of the preceding claims, characterized in that two tubular preforms (76.1 to 76.4) are connected by at least one ply of glue (88) and / or at least one ply of fibers (90) intercalated between the two tubular preforms (76.1 to 76.4).
11. A method for obtaining a blade grid according to any 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. A method for obtaining a blade grid according to any one of claims 1 to 10, characterized in that during the manufacturing step, each tubular preform (76.1 to 76.4) is totally baked or polymerized.
13. Blade grid obtained from a production process according to one of the preceding claims.
14. Aircraft comprising at least one blade grid according to the preceding claim.