Method for manufacturing a fibrous preform for a blade or propeller comprising a hybrid root
Patent Information
- Application Number
- PCT/FR2026/010013
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-04-15
- Filing Date
- 2026-04-15
- Publication Date
- 2026-10-22
Smart Images
Figure FR2026010013_22102026_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Title of the invention: Method for manufacturing a fibrous preform of a blade or propeller comprising a hybrid foot
[0003] Technical Field
[0004] The present invention relates to the field of preforms used to manufacture parts from composite materials. It relates more particularly to the production of preforms for aeronautical engine blades or propellers.
[0005] Previous technique
[0006] The new generation of unfaired engines (known as "open fan" or "open rotor" engines) requires more compact blade bases. This need arises from the necessity of being able to rotate the blade around its vertical axis in order to adapt its angle of attack to the flight regime (variable pitch blade).
[0007] For this purpose, the feet of the blades have an axisymmetric or substantially axisymmetric shape and reduced dimensions like the blade disclosed in document WO 2023 / 209289.
[0008] A new hybrid blade foot design is being considered. It includes a fibrous reinforcement between an outer metal shell and an inner metal core, with an additional cylindrical metal ring inserted into the fibrous reinforcement.
[0009] In order to allow the insertion of the cylindrical ring into the fibrous reinforcement, the latter is formed of several layers or skins separated from each other and between which the cylindrical ring is inserted.
[0010] However, inserting the cylindrical ring is problematic. It is not possible to create an insertion cavity for the ring within the fibrous preform, primarily because this would require wetting and then drying the preform, which is incompatible with the presence of an adhesive film between the outer shell and the preform. The only option, therefore, is to insert the cylindrical ring between the layers of the fibrous preform without prior shaping. If the cylindrical ring is inserted before any prior shaping of the preform layers, it becomes impossible to compact the layers between the ring and the outer shell due to the rigidity of these two components.
[0011] Furthermore, if the hides are compacted before the ring is placed between them, the ring's insertion will cause excessive friction, which can significantly impact the material's integrity. Indeed, the ring's insertion angle promotes the removal of fibers, leading to the formation of blockages at the end of the ring that is inserted first between the hides.
[0012] Significant friction between the compacted skin and the ring during insertion can lead to the following problems:
[0013] - The very high force required to insert the ring can lead to its deterioration.
[0014] - The ring carries away numerous fibers as it passes, creating blockages at the bottom of the debonding zone, with the risk of also carrying away the skins. - The ring may not reach its nominal position, resulting in inconsistent compaction rates within the preform.
[0015] - Friction during insertion tends to misalign the different layers of the preform.
[0016] - The overall physical health inside the foot is unsatisfactory.
[0017] Description of the invention
[0018] It is therefore desirable to be able to propose a solution for the production of blade or propeller preforms that do not present the aforementioned disadvantages.
[0019] To this end, the present invention proposes a method for manufacturing a blade or propeller preform comprising at least one airfoil portion and one base preform portion, the method comprising:
[0020] - the three-dimensional weaving of a fibrous blank between a plurality of layers of warp yarns extending along a longitudinal direction and a plurality of layers of weft yarns extending along a transverse direction, the warp yarns being woven in a plurality of columns spaced apart along the transverse direction, the fibrous blank comprising at least an aerodynamic profile part and a foot part, the foot part comprising first, second, third and fourth fibrous skins each extending along the longitudinal direction between a first free end and a second end, along the transverse direction between first and second lateral edges, the first, second, third and fourth fibrous skins being superimposed along a thickness direction,
[0021] - the insertion of the first, second, third and fourth fibrous skins into a tubular outer shell,
[0022] - the supply of a cylindrical ring formed from N independent sectors,
[0023] - the insertion of N-1 sectors of the cylindrical ring between, on the one hand, the first and fourth fibrous skins and, on the other hand, the second and third fibrous skins
[0024] - the compaction of the first, second, third and fourth fibrous skins against an internal surface of the tubular outer shell,
[0025] - the insertion of a final sector of the cylindrical ring between, on the one hand, the first and fourth fibrous skins and the second and third fibrous skins, on the other hand.
[0026] The use of a segmented ring, in which the N-1 sectors are first inserted between the first and fourth uncompacted fibrous skins and the second and third uncompacted fibrous skins, allows for the reconstitution of the first part of the ring without excessive friction on the fibrous skins and, consequently, without removing any fibers from them. Furthermore, the insertion of the sectors can be carried out with additional degrees of freedom, allowing each sector to be inserted at a slight angle to the direction. This angle further facilitates sector insertion and drastically reduces the risk of fiber removal during their placement.
[0027] The compaction of the first, second, third, and fourth fibrous skins, performed after the insertion of the N-1 sectors of the cylindrical ring, achieves the desired fiber volume ratio while positioning the N-1 sectors to allow space for the insertion of the last sector of the cylindrical ring. Inserting the last sector is effortless because compacting the fibrous skins with the N-1 sectors against the inner surface of the outer shell enlarges the radius and, consequently, the perimeter of the recess into which the N-1 sectors were inserted. This creates a gap between two sectors for the insertion of the last sector without significant friction with the fibrous skins. Once inserted, the last sector acts as a keystone, holding the ring in position and the fibrous skins in a compacted state.
[0028] According to a particular feature of the manufacturing process for a blade or propeller preform, the first and second lateral edges of the first, second, third, and fourth fiber layers have a beveled shape. Each beveled lateral edge of one of the fiber layers is designed to cooperate with a beveled lateral edge of the other fiber layer to ensure continuity in the thickness of the formed fiber preform.
[0029] According to another particular feature of the manufacturing process of a blade or propeller preform, the cylindrical ring is formed of six sectors.
[0030] According to another particular feature of the manufacturing process for a blade or propeller preform, an internal surface of the cylindrical ring has a cylindrical shape, while an external surface of said cylindrical ring has a hexagonal shape. The process of the invention makes it possible to shape the fibrous skins according to two different geometries, namely circular hexagonal inward and hexagonal outward.
[0031] According to another particular feature of the manufacturing process of a blade or propeller preform, the compaction of the first, second, third and fourth fibrous skins against an internal surface of the tubular outer shell is carried out by means of a spacing tool placed against the internal face of the second and third fibrous skins.
[0032] According to another particular feature of the blade or propeller preform manufacturing process, each sector of the cylindrical ring has a beveled end. Each sector is inserted between the first and fourth fiber skins on one side, and the second and third fiber skins on the other, starting from this beveled end. This facilitates guiding the sectors between the fiber skins while reducing the risk of fibers being carried away from them.
[0033] The invention also relates to a method for manufacturing a blade or propeller made of composite material comprising manufacturing a preform of the blade or propeller according to the method for manufacturing a preform of the blade or propeller of the invention and densification by a matrix of said fibrous preform.
[0034] The invention also relates to a blade or propeller preform manufactured according to the manufacturing process of a blade or propeller preform of the invention.
[0035] The invention also relates to a blade or propeller made of composite material manufactured according to the manufacturing process of a blade or propeller made of composite material of the invention.
[0036] Brief description of the drawings
[0037] [Fig. 1] Figure 1 is a schematic perspective view illustrating a fibrous blank for the manufacture of a fibrous preform of a blade or propeller according to one embodiment of the invention,
[0038] [Fig. 2] Figure 2 is a schematic perspective view showing the shaping of a portion of the foot of the fibrous blank of Figure 1,
[0039] [Fig. 3] Figure 3 is a schematic, enlarged perspective view of the outer shell and segmented cylindrical ring of Figure 2,
[0040] [Fig. 4] Figure 4 is a cross-sectional view of the foot portion of the fibrous blank of Figure 1 showing the insertion of ring sectors, [Fig. 5] Figure 5 is a schematic cross-sectional view along the VV plane of the foot portion of Figure 4,
[0041] [Fig. 6] Figure 6 is a cross-sectional view of the foot portion during the compaction of the fibrous skins,
[0042] [Fig. 7] Figure 7 is a schematic cross-sectional view along plane VII-VII of the foot portion of figure 6,
[0043] [Fig. 8] Figure 8 is a schematic view of Figure 7 after the insertion of a final ring sector. Description of embodiments
[0044] The invention applies generally to the manufacture of fibrous preforms for forming parts made of composite material. The invention finds an advantageous, but not exclusive, application in the manufacture of blades or propellers for unfaired rotating wheels, such as those used in so-called "open rotor" aircraft engines.
[0045] In the following description, examples of embodiments are described in relation to the manufacture of a blade or propeller for unfaired moving wheels of a turbomachine. However, the examples of embodiments also apply to other types of blade or propeller.
[0046] Figure 1 shows very schematically a fibrous blank 100 intended to form the fibrous preform of a blade to be produced.
[0047] The fibrous blank 100 is obtained, as schematically illustrated in Figure 1, by three-dimensional (3D) weaving carried out in a known manner using a Jacquard-type loom on which a bundle of warp yarns 101 or strands is arranged in a plurality of layers of several hundred yarns each, the warp yarns being linked by weft yarns 102. The fibrous blank 100 is woven in a single piece, the blank comprising an aerodynamic profile portion 110 extending in a longitudinal direction DL, corresponding to the span direction of the blade to be manufactured, between a lower portion 100c and an upper portion 100d; in a transverse direction DT, corresponding to the chord direction of the blade to be manufactured, between a leading edge 100a and a trailing edge 100b; and in a thickness direction DE between two faces 110e and 110f intended to form, respectively, the extrados and intrados faces of the dawn.
[0048] The fibrous blank 100 also includes a foot portion 120 intended to subsequently form a blade foot and extending outside the airfoil portion 110 from the lower portion 100c, the latter following the longitudinal direction and set back from the leading and trailing edges 100a and 100b in the transverse direction DT. In the illustrated example, the 3D weave is an interlock weave. By interlock weave, we mean here a weave structure in which each layer of weft yarns interlocks several layers of warp yarns, with all the yarns in the same weft column having the same movement in the plane of the weave.
[0049] Other known three-dimensional weaving types may be used, such as those described in document US2007 / 007386. This document describes in particular the production by weaving in one piece of fibrous reinforcement structures for parts such as blades having a first type of core armor and a second type of skin armor which make it possible to confer both the mechanical and aerodynamic properties expected for this type of part.
[0050] The fibrous blank according to the invention can be woven in particular from carbon fiber yarns or ceramic such as silicon carbide.
[0051] As the airfoil section 110, whose thickness and width vary, is woven, a certain number of warp threads are not woven, which allows the continuously variable contour and desired thickness of the airfoil section 110 to be defined. An example of evolving 3D weaving, which notably allows the thickness of the blank to be varied between a first edge intended to form the leading edge and a second edge of lesser thickness intended to form the trailing edge, is described in US document 2006 / 257260.
[0052] According to the invention, the weaving of the fiber blank 100 comprises weaving a first fiber skin 130, a second fiber skin 140, a third fiber skin 150, and a fourth fiber skin 160 superimposed along a thickness direction DE of the fiber blank and forming the foot portion 120. The first fiber skin 130 has a flat shape and extends along the longitudinal direction DL from the lower part 100c of the airfoil portion 110 to a free end 132, along the transverse direction DT between the first and second lateral edges 135 and 136. Similarly, the second fiber skin 140 has a flat shape and extends along the longitudinal direction DL from the lower part 100c of the airfoil portion 110 to a free end 142, along the transverse direction DT between the first and second lateral edges 145 and 146.Similarly, the third fibrous skin 150 has a flat shape and extends along the longitudinal direction DL from the lower part 100c of the aerodynamic profile part 110 to a free end 152, along the transverse direction DT between the first and second lateral edges 155 and 156. Similarly, the fourth fibrous skin 160 has a flat shape and extends along the longitudinal direction DL from the lower part 100c of the aerodynamic profile part 110 to a free end 162, along the transverse direction DT between the first and second lateral edges 165 and 166.
[0053] In the example described here, the first and second lateral edges 135, 136, 145, 146, 155, 156, 165, 166 respectively of the first to fourth fiber layers 130 to 160 each have a beveled shape. More precisely, during the weaving of the first and second lateral edges 135, 136, 145, 146, 155, 156, 165, 166 respectively of the first to fourth fiber layers 130 to 160, the warp and weft yarns are progressively brought out in such a way as to form beveled lateral edges (also called "scarf" in English).
[0054] Each beveled lateral edge of one of the fibrous skins is intended to cooperate with a beveled lateral edge of the other fibrous skin in order to have continuity in the thickness of the formed fibrous preform.
[0055] Once the weaving is finished, the non-woven yarns around the 100 fibrous blank are cut to extract the blank, then the foot part of the blank is shaped.
[0056] As illustrated in Figure 2, the shaping of the foot part 120 begins with the insertion of the first, second, third and fourth fibrous skins 130, 140, 150, 160 into a tubular outer shell 10. In the example described here and as illustrated in Figure 3, the tubular outer shell 10 comprises at least a first section 11 having a first diameter and a second section 12 having a second diameter smaller than the first diameter.
[0057] During their insertion into the cylindrical outer shell 10, the first and second fibrous skins 130, 140 are bent along a direction Dm to conform to the cylindrical geometry of the outer shell, while the third and fourth fibrous skins 150, 160 are bent along a direction Dc2 to also conform to the cylindrical geometry of the outer shell. The shaping of the foot portion continues with the insertion of a cylindrical ring 20. According to the invention, the cylindrical ring is sectorized, that is, it is divided into a number N of sectors which, when assembled together, form the cylindrical ring. In the example described here and as shown in Figure 3, the cylindrical ring 20 comprises six sectors 21, 22, 23, 24, 25, and 26 of similar size and geometry.
[0058] According to the invention, the N sectors of the cylindrical ring are inserted one after the other between, on the one hand, the first and fourth fibrous skins 130 and 160 and, on the other hand, the second and third fibrous skins 140 and 150, in two separate operations. More precisely, N-1 sectors of the ring are inserted first, the last sector being inserted subsequently after compaction of the fibrous skins as explained in detail below.
[0059] In the example described here, firstly, the first and fourth fibrous skins 130 and 160 and the second and third fibrous skins 140 and 150 are inserted between, on the one hand, five of the six sectors of the cylindrical ring, here sectors 21, 22, 23, 24 and 26. The sectors are positioned at the level of the first section 11 of the tubular outer shell 10.
[0060] Figures 4 and 5 illustrate the foot portion 120 after the insertion of the first, second, third, and fourth fibrous skins 130, 140, 150, and 160 into the tubular outer shell 10, followed by the insertion of sectors 21, 22, 23, 24, and 26 of the cylindrical ring 20 between, on the one hand, the first and fourth fibrous skins 130 and 160, and on the other hand, the second and third fibrous skins 140 and 150. Sectors 21, 22, 23, 24, and 26 are inserted sequentially at specific locations as shown in Figure 5.
[0061] The sector-by-sector insertion of the N-1 sectors of the cylindrical ring, here sectors 21, 22, 23, 24, and 26, between, on the one hand, the first and fourth fibrous skins 130 and 160 in their uncompacted state and, on the other hand, the second and third fibrous skins 140 and 150 in their uncompacted state, allows for the reconstruction of the first part of the ring without excessive friction on the fibrous skins and, consequently, without removing any fibers from them. Furthermore, the insertion of the sectors can be carried out with additional degrees of freedom, allowing each sector to be inserted at a slight angle to the direction, as illustrated in Figure 3 for sectors 21 and 23. This angle further facilitates the insertion of the sectors and drastically reduces the risk of removing fibers during their placement.
[0062] Furthermore, each sector of the cylindrical ring has a beveled end like the ends 210 and 230 respectively of sectors 21 and 23 illustrated in Figure 4. Each sector is thus inserted between, on the one hand, the first and fourth fibrous skins 130 and 160 and the second and third fibrous skins 140 and 150, on the other hand by its beveled end, which facilitates the guidance of the sectors between the fibrous skins while reducing the risk of carrying away fibers from the latter.
[0063] The process continues with the compaction of the first, second, third and fourth fibrous skins 130, 140, 150 and 160. More precisely, as shown in figures 6 and 7, a spacing tool 30 is placed in a central free space 170 delimited by the second and third fibrous skins 140 and 150. The tool can, for example, correspond to a bladder or any other means suitable for exerting a homogeneous compaction force Fc.
[0064] During the compaction of the first, second, third, and fourth fibrous skins 130, 140, 150, and 160 against the inner surface of the tubular outer shell 10, the radius, and consequently the perimeter, of the cavity into which sectors 21, 22, 23, 24, and 26 have been inserted is enlarged. This allows for the formation of a cavity I25 between two sectors, here sectors 24 and 26, for the insertion of the last sector, here sector 25, as shown in Figure 7. The compaction performed after the insertion of the N-1 sectors of the cylindrical ring allows the desired fiber volume ratio to be achieved while positioning the N-1 sectors in such a way as to leave room for the insertion of the last sector of the cylindrical ring without significant friction with the fibrous skins. After compaction, the last sector 25 is positioned in the cavity I25.
[0065] This yields a fibrous blade preform comprising a portion of the airfoil preform corresponding to the airfoil portion 110 of the fibrous blank (Figure 2) and a portion of the foot preform. Figure 8 shows a portion of the foot preform 220 obtained after the insertion of the last sector 25 of the cylindrical ring 20 into the housing 20 and an internal sleeve 40. The portion of the foot preform 220 thus forms a hybrid structure comprising, from the inside out, the internal sleeve 40, two internal fibrous skins 240 and 250 formed by the second and third fibrous skins 140 and 150 shaped and compacted, the cylindrical ring 20 formed by the six sectors 21 to 26, two external fibrous skins 230 and 260 formed by the first and fourth fibrous skins 130 and 160 shaped and compacted, and the tubular outer shell 10.
[0066] The fibrous blade preform is then densified to obtain the final blade made of composite material. Densification is carried out using a well-known liquid-based process. This process involves impregnating the preform with a liquid composition containing a precursor of the matrix material. The precursor is usually a polymer, such as a high-performance epoxy resin, possibly diluted in a solvent. The preform is placed in a mold that can be sealed tightly with a cavity shaped like the final molded blade. The mold is then closed, and the liquid matrix precursor (e.g., a resin) is injected into the entire cavity to impregnate the entire fibrous portion of the preform.The transformation of the precursor into a matrix, namely its polymerization, is carried out by heat treatment, generally by heating the mold, after removal of any solvent and crosslinking of the polymer, the preform always being kept in the mold having a shape corresponding to that of the part to be produced.
[0067] In the case of carbon or ceramic matrix formation, heat treatment consists of pyrolyzing the precursor to transform the matrix into a carbon or ceramic matrix, depending on the precursor used and the pyrolysis conditions. For example, liquid carbon precursors can be resins with relatively high coke content, such as phenolic resins, while liquid ceramic precursors, particularly SiC, can be polycarbosilane (PCS), polytitanocarbosilane (PTCS), or polysilazane (PSZ) type resins. Several consecutive cycles, from impregnation to heat treatment, can be performed to achieve the desired degree of densification. Alternatively, an epoxy resin with a temperature class of 180 °C (maximum temperature withstood without loss of properties) can be used.The choice of temperature class and / or the chemical nature of the resin is determined according to the thermomechanical stresses to which the part must be subjected. The densification processes described above make it possible to produce, from the fibrous preform of the invention, primarily parts such as blades or propellers made of organic matrix composite (OMC), carbon matrix composite (C / C), and ceramic matrix composite (CMC).
[0068] The transformation of the precursor into a matrix, namely its polymerization, is carried out by heat treatment, generally by heating the mold, after the removal of any solvent and crosslinking of the polymer. The preform remains in the mold, which has a shape corresponding to that of the blade. The matrix can be obtained, in particular, from epoxy resins, such as the high-performance epoxy resin sold under the reference PR 520 by CYTEC.
[0069] According to one aspect of the invention, the densification of the blade's fibrous preform can be achieved by the well-known resin transfer molding (RTM) process. In the RTM process, the fibrous preform is placed in a mold having the external shape of the blade. A thermosetting resin is injected into the internal space between the rigid material part and the mold, which includes the fibrous preform. A pressure gradient is generally established in this internal space between the point where the resin is injected and the resin's discharge ports in order to control and optimize the resin impregnation of the preform.
[0070] The resin used can be, for example, an epoxy resin. Resins suitable for RTM processes are well-known. They preferably have a low viscosity to facilitate their injection into the fibers. The choice of temperature class and / or the chemical nature of the resin is determined according to the thermomechanical stresses to which the part will be subjected. Once the resin has been injected throughout the reinforcement, it is polymerized by heat treatment according to the RTM process.
[0071] This results in a blade made of composite material comprising an aerodynamic profile and a hybrid foot made up of the preform part of foot 220.
Claims
Demands
1. A method for manufacturing a blade or propeller preform comprising at least one airfoil portion and one root preform portion (220), the method comprising: - the three-dimensional weaving of a fibrous blank (100) between a plurality of layers of warp yarns (101) extending along a longitudinal direction (DL) and a plurality of layers of weft yarns (102) extending along a transverse direction (DT), the warp yarns (101) being woven in a plurality of columns spaced apart along the transverse direction (DT), the fibrous blank (100) comprising at least an airfoil portion (110) and a foot portion (120), the foot portion comprising first, second, third and fourth fibrous skins (130, 140, 150, 160) each extending along the longitudinal direction (DL) between the airfoil portion (110) and a free end (132, 142, 152, 162), along the transverse direction (DT) between first and second lateral edges (135, 136, 145, 146, 155, 156, 165, 166), the first, second, third and fourth fibrous skins (130, 140, 150,160) being superimposed along a thickness direction (DE), - the insertion of the first, second, third and fourth fibrous skins (130, 140, 150, 160) into a tubular outer shell (10), - the supply of a cylindrical ring (20) formed of a number N of independent sectors, - the insertion of N-1 sectors of the cylindrical ring (20) between, on the one hand, the first and fourth fibrous skins (130, 160) and the second and third fibrous skins (140, 150), on the other hand, - the compaction of the first, second, third and fourth fibrous skins against an internal surface of the tubular outer shell (10), - the insertion of a last sector of the cylindrical ring between, on the one hand, the first and fourth fibrous skins (130, 160) and the second and third fibrous skins (140, 150), on the other hand.
2. A method according to claim 1, wherein the first and second lateral edges (135, 136, 145, 146, 155, 156, 165, 166) of the first, second, third and fourth fibrous skins (130, 140, 150, 160) have a beveled shape.
3. A method according to claim 1 or 2, wherein the cylindrical ring (20) is formed of six sectors (21, 22, 23, 24, 25, 26).
4. A method according to any one of claims 1 to 3, wherein an internal surface of the cylindrical ring (20) has a cylindrical shape while an external surface of said cylindrical ring has a hexagonal shape.
5. A method according to any one of claims 1 to 4, wherein the compaction of the first, second, third and fourth fibrous skins (130, 140, 150, 160) against an internal surface (10b) of the tubular outer shell (10) is carried out by means of a spacing tool (30) placed against the internal face of the second and third fibrous skins.
6. A method according to any one of claims 1 to 5, wherein each sector of the cylindrical ring (20) has a beveled end, each sector being inserted between, on the one hand, the first and fourth fibrous skins (130, 160) and the second and third fibrous skins (140, 150), on the other hand, from said beveled end.
7. Method of manufacturing a blade or propeller of composite material comprising manufacturing a blade or propeller preform according to any one of claims 1 to 6 and densifying said fibrous preform with a matrix.
8. Blade or propeller preform manufactured according to the method according to any one of claims 1 to 6.
9. Blade or propeller made of composite material manufactured according to the process of claim 7.