Blade comprising a structural element made of composite material and related manufacturing method

Abstract

The invention relates to a blade (7) comprising: - a structural piece (17) made of composite material; - a blade root attachment part (9) comprising a wall (25) delimiting a cavity (28), a first opening (29) formed in the wall (25) and a second opening (30) located below a blade root portion (22), the structural piece (17) made of composite material extending through the first opening (29); - two locking parts (19) configured to axially abut against a shoulder (10) of the attachment part (9) and configured to bear against the blade root portion (22); and - a cover (31) for compressing the blade root portion (22) against the locking parts (19).

Description

Technical Field

[0001] The present invention relates to a blade comprising a structural component made of composite material.

[0002] The present invention relates more particularly, but not exclusively, to a blade intended for use in a ductless fan rotor of an aircraft engine (e.g., an "open rotor" engine (i.e., for which the fan has no duct and has two rotating propellers) or a "ductless single fan" (USF) engine having a moving blade section and a fixed blade section or a turboprop engine having an architecture including a single propeller) or a wind turbine rotor. Background Technology

[0003] The advantage of ductless fan engines is that the diameter of the fan is not limited by the presence of a cowling, so engines with high bypass ratios can be designed, thereby reducing fuel consumption.

[0004] Therefore, in this type of engine, the fan blades can have a large span.

[0005] In addition, these engines typically include mechanisms for changing the blade pitch angle to adjust the power generated by the fan according to different phases of flight.

[0006] However, the design of this blade requires consideration of the opposite constraints.

[0007] On the one hand, the size of these blades must enable optimal aerodynamic performance (maximizing efficiency and providing thrust while minimizing losses). Improvements in fan aerodynamic performance tend to increase the bypass ratio (BPR), which is reflected in the increase of the outer diameter and the span of these blades.

[0008] On the other hand, it is also necessary to ensure that these blades are subjected to mechanical stress, which can be applied to these blades while limiting their acoustic characteristics.

[0009] Furthermore, in ductless fan architectures, the engine typically starts with a very wide pitch. More specifically, this very wide pitch allows power to be consumed by torque, which ensures mechanical safety by maintaining a low fan speed.

[0010] However, with a very wide blade pitch, the blades are subjected to completely isolated turbulent aerodynamic flows, which generates broadband vibrational excitation. Especially on blades with wide chords and large spans, the bending forces are strong even when the engine speed is not at its maximum.

[0011] During normal operation, the pitch changes (the pitch angle becomes more closed) during the ground and flight phases. Therefore, the aerodynamic flow is very clean (reattached to the aerodynamic profile). Broadband stress disappears, rotational speeds are higher, and bending forces are controlled.

[0012] Currently, these blades are typically made of metal. While metal blades have good mechanical strength, their disadvantage is that they have a relatively large mass.

[0013] To reduce this mass, it is desirable to manufacture these blades using composite materials. However, the intense aerodynamic forces these blades will be subjected to pose a risk of damage to the blades and / or the hub in the interface region between the blades and the hub of the fan rotor. More specifically, this problem arises due to the engine-grade vibration levels AN, 2N, and 3N when the blades are fastened to the hub by pins. Summary of the Invention

[0014] The object of this invention is to provide a blade comprising a composite material, which is suitable for use with a variable pitch mechanism and in an "open rotor" environment, while being able to withstand strong aerodynamic forces under constraints of limited size and minimum mass.

[0015] Therefore, a first aspect of the present invention provides a blade comprising:

[0016] -Structural components made of composite materials, including fiber reinforcements obtained by three-dimensional weaving and a matrix in which the fiber reinforcements are embedded; structural components made of composite materials include wing portions and blade root portions with aerodynamic profiles.

[0017] - A blade root attachment component, comprising a wall defining a cavity, a first opening formed in the wall, and a second opening located below the blade root portion, the second opening being located on the opposite side of the attachment component relative to the first opening, a structural member made of composite material extending through the first opening such that the wing portion is located outside the attachment component and the blade root portion is located inside the cavity, the attachment component also comprising a shoulder extending from the wall into the cavity.

[0018] - Two locking components, each having an upper surface and a lower surface, the upper surface being configured to axially abut against a shoulder, and the lower surface being inclined relative to the upper surface and configured to support a portion abutting the blade root; and

[0019] - A cover, which is fixed to the attachment member at the second opening, such that the root portion of the blade is compressed between the cover and the locking member, and at least one recess is formed in the shoulder, with each locking member being received in at least one recess.

[0020] According to some preferred but non-limiting features of the first aspect, the following features are used alone or in combination:

[0021] - The locking member is supported against the recess, at least one recess is formed in the shoulder, and each locking member is received in at least one recess;

[0022] - The shoulder has a radial surface extending opposite to the root portion of the blade, and each locking member includes a tab extending from the upper surface of the locking member, the tab being configured to radially abut against the radial surface of the shoulder; and / or

[0023] - The fiber reinforcement includes a wing fiber reinforcement portion and a blade root fiber reinforcement portion, wherein each blade root fiber reinforcement portion is continuously woven with the wing fiber reinforcement portion.

[0024] According to a second aspect, the present invention provides a method for manufacturing a blade according to a first aspect, the blade comprising a fiber reinforcement obtained by three-dimensional weaving, the fiber reinforcement comprising an airfoil fiber reinforcement portion and a blade root fiber reinforcement portion, the method comprising the following steps:

[0025] - Manufacture the blade root attachment components to form the cavity and shoulder;

[0026] - The fiber reinforcement is arranged in the attachment member through the opening, such that the wing fiber reinforcement portion is located outside the attachment member, beyond the first opening, and a portion of the blade root fiber reinforcement portion is located outside the attachment member, beyond the second opening;

[0027] - The locking component is arranged in the cavity such that the upper surface of the locking component axially abuts against the shoulder;

[0028] - The fiber reinforcement is arranged in the attachment member such that the fiber reinforcement portion at the blade root is located inside the attachment member and supports the inclined lower surface of the locking member; and

[0029] - At the second opening, the cover is secured to the attachment by compressing the root portion of the blade between the cover and the locking component.

[0030] Some preferred but non-limiting features of the method for manufacturing blades according to the second aspect are the following features, used alone or in combination:

[0031] - The method also includes the steps of arranging the fiber reinforcement in a mold, and injecting plastic material into the mold prior to the arrangement step S3 to form a structural component made of composite material including the fiber reinforcement and a matrix inlaid with the fiber reinforcement;

[0032] The method further includes the steps of arranging the assembly formed by the fiber reinforcement, attachment members, and locking members in a mold, and, prior to the step S6 of fixing the cap, injecting plastic material into the mold to form a structural member made of composite material including the fiber reinforcement and a matrix inlaid with the fiber reinforcement; and / or

[0033] The method further includes, prior to the step of arranging the component in the mold, abutting against the root portion of the fiber reinforcement and / or arranging it at the second opening, and prior to the step of fixing the cover, removing the temporary protective element.

[0034] According to a third aspect, the present invention provides a gas turbine engine including a fan, the fan including a hub and blades extending radially from the hub, the blades being blades according to the first aspect, each blade being mounted to rotate relative to the hub about a corresponding pitch axis, the engine also including an actuating mechanism that can be controlled to rotate the blades about the blade's pitch axis, thereby changing the blade's pitch angle.

[0035] According to a fourth aspect, the present invention proposes an aircraft comprising a gas turbine engine according to a third aspect.

[0036] According to a fifth aspect, the present invention provides a blade comprising:

[0037] -Structural components made of composite materials, including fiber reinforcements obtained by three-dimensional weaving and a matrix in which the fiber reinforcements are embedded; structural components made of composite materials include wing portions and blade root portions with aerodynamic profiles.

[0038] - A blade root attachment component, comprising a wall defining a cavity, a first opening formed in the wall, and a second opening located below the blade root portion, the second opening being located on the opposite side of the attachment component relative to the first opening, a structural member made of composite material extending through the first opening such that the wing portion is located outside the attachment component and the blade root portion is located inside the cavity, the attachment component also comprising a shoulder extending from the wall into the cavity.

[0039] - Two locking components, each having an upper surface and a lower surface, the upper surface being configured to axially abut against a shoulder, and the lower surface being inclined relative to the upper surface and configured to support a portion abutting the blade root; and

[0040] - The cover is fixed to the attachment member at the second opening, so that the root portion of the blade is compressed between the cover and the locking member;

[0041] The shoulder has a radial surface extending opposite to the root portion of the blade, and each locking member includes a tab extending from the upper surface of the locking member, the tab being configured to radially abut against the radial surface of the shoulder. Attached Figure Description

[0042] Other features, objects, and advantages of the invention will become apparent from the following description, which is given entirely in an illustrative and non-limiting manner and should be read with reference to the accompanying drawings, in which:

[0043] Figure 1 An exemplary engine including a ductless fan is schematically shown;

[0044] Figure 2 The fan blades and the actuation mechanism for changing the pitch angle of the fan blades are schematically shown.

[0045] Figure 3 This is a schematic cross-sectional view of a fan blade according to a first embodiment of the present invention;

[0046] Figure 4 The diagram schematically illustrates a structural component made of composite material that forms part of the blade;

[0047] Figure 5 and Figure 6 An exemplary embodiment of three-dimensional weaving of fiber reinforcements of blades on a loom is illustrated schematically according to an embodiment of the present invention.

[0048] Figure 7 The mounting of the fan blades according to the second embodiment is shown schematically.

[0049] Figure 8 The mounting of the fan blades according to the second embodiment is shown schematically.

[0050] Figure 9 and Figure 10 This is a flowchart of the steps of the method according to the first and second embodiments of the present invention.

[0051] In all figures, similar elements have the same reference numerals. Detailed Implementation

[0052] exist Figure 1 In the diagram, engine 1 is an "open rotor" engine, a configuration commonly referred to as a "thruster" configuration (i.e., a ductless fan is positioned behind the electric generator, and the air inlet is located at...). Figure 1 (The right side of the middle).

[0053] The engine includes a nacelle 2 and a ductless fan 3, the nacelle being designed to be fixed to the aircraft fuselage. The fan 3 includes two counter-rotating fan rotors 4 and 5. In other words, when the engine 1 is running, rotors 4 and 5 rotate in opposite directions relative to the nacelle 2 about the same axis of rotation X (which coincides with the main axis of the engine).

[0054] exist Figure 1 In the example shown, engine 1 is an "open rotor" engine of a "pusher" configuration, which has fan rotors rotating in opposite directions. However, the invention is not limited to this configuration. The invention is also applicable to "open rotor" engines of a "puller" configuration (i.e., the fan is arranged upstream of the electric generator, and the air inlet is located in front of, between, or behind the two fan rotors).

[0055] Furthermore, the present invention is also applicable to engines with different architectures, such as those including a fan rotor (including moving blades) and a fan stator (including fixed blades), or an architecture including a single fan rotor.

[0056] This invention applies to turboprop engine architectures (including a single fan rotor).

[0057] exist Figure 1 In this configuration, each fan rotor 4, 5 includes a hub 6 mounted to rotate relative to the nacelle 2 and a plurality of blades 7 fixed to the hub 6. The blades 7 extend approximately radially relative to the axis of rotation X of the hub.

[0058] like Figure 2 As shown, the fan 3 also includes an actuation mechanism 8 for jointly modifying the pitch angle of the rotor blades to adjust the engine performance to different flight phases. For this purpose, each blade 7 includes an attachment member 9 (or hub) disposed at the blade root. The attachment member 9 is mounted to rotate relative to the hub 6 about the pitch axis Y. More precisely, the attachment member 9 is mounted to rotate within a receiving portion 10 disposed in the hub 6 by means of a spherical portion 11 or other rolling element.

[0059] The actuation mechanism 8 includes an actuator 12 comprising a body 13 fixed to the hub 6 and a rod 14 translatably driven relative to the body 12. The actuation mechanism 8 also includes an annular slider 15 integrally mounted with the rod 14 and a pin 16 integrally mounted with the attachment member 9. The pin 16 is slidable within and rotatable relative to the slider 15, thereby converting the translational motion of the rod 14 into rotational motion of the attachment member 9, and thus into rotational motion of the blade 7 relative to the hub 6 about its pitch axis Y.

[0060] The fan blade 7 includes a structural member 17 made of composite material, an attachment member 7 at the blade root 7, two locking members 19, and a cover 31.

[0061] The structural component 17 made of composite material includes a fiber reinforcement 33 obtained by three-dimensional weaving and a matrix 34 in which the fiber reinforcement 33 is embedded.

[0062] The fiber reinforcement can be formed as a single piece from a fiber preform, which is obtained through three-dimensional or multi-layer weaving with scalable thickness. Specifically, the fiber reinforcement can include carbon, glass, aramid, and / or ceramic fibers. The matrix of the yarn coating the fiber reinforcement 33 is typically a plastic material, usually a polymer such as an epoxide, bismaleimide, or polyimide, or a carbon matrix. The blade 1 is then formed by molding using a resin transfer molding (RTM) type or even a vacuum resin injection molding (VARRTM) type.

[0063] The fiber reinforcement 33 is woven such that the fiber reinforcement includes warp yarns that extend continuously inside the wing portion 21 with an aerodynamic profile and inside the blade root portion 22.

[0064] The composite material structural member 17 includes an aerodynamically contoured wing portion 21 and a blade root portion 22. When the engine is running, the aerodynamically contoured wing portion 21 can be positioned in the airflow to generate lift. The blade root portion 22 is designed to allow the composite material structural member 17 to be secured to the attachment member 9.

[0065] The blade root portion 22 is continuously connected to the wing portion 21. The blade root portion 22 has an increased thickness as it moves away from the wing portion 21, which has an aerodynamic profile.

[0066] The attachment member 9 is made of metal, such as martensitic steel. The attachment member 9 includes a wall 25 having an outer surface 26 with a rotationally symmetrical shape. The outer surface 26 has two circular grooves 27, which are capable of forming raceways for the spherical portion 11 or other rolling elements.

[0067] The wall 25 of the attachment member 9 defines a cavity 28 configured to receive the blade root portion 22 of a structural member 17 made of composite material. The wall 25 has a first opening 29 of generally rectangular shape through which the structural member 17 extends, such that the wing portion 21 is located outside the attachment member 9. The attachment member 9 also has a second opening 30 larger than the first opening 29, located below the blade root portion 22 and on the opposite side of the attachment member 9 relative to the first opening 28. The second opening 30 may be circular if desired.

[0068] The attachment member 9 also includes a shoulder 10 extending from the wall 25 into the cavity 28. Specifically, the shoulder 10 can be obtained by machining the inner surface of the wall 25. The shoulder 10 extends continuously or discontinuously along the inner periphery of the wall 25. In an embodiment, the shoulder 10 is discontinuous and comprises two separate segments extending opposite each other, for example, opposite the blade root portion 22, which extends within the extensions of the pressure and suction walls of the blade 7.

[0069] The shoulder 10 has an upper surface 10a facing the first opening 29, a lower surface 10b facing the second opening 30, and a radial surface 10c extending toward the root portion 22 of the blade.

[0070] Locking members 19 are also disposed inside cavity 28. Each locking member has an upper surface 19a and a lower surface 19b, the upper surface 19a being configured to axially abut against the lower surface 10a of shoulder 10 (or corresponding shoulder segment 10), the lower surface 19b being at least partially inclined relative to the upper surface 19a and configured to support the blade root portion 22. For this purpose, the angle formed between the upper surface 19a and the inclined lower surface 19b is an acute angle. The lower surface 19b may be generally planar and inclined along its entire length, in which case the locking member 19 is generally triangular. Alternatively, the lower surface 19b may have an inclined radially inner portion (i.e., near the pitch axis Y) and a radially outer portion generally parallel to the upper surface 19a (i.e., near the wall 25). Figure 7 and Figure 8 Therefore, the upper surface 19a of the locking member 19 enables the locking member 19 and thus the axial position of the blade root portion 22 relative to the attachment member 9 to be fixed, while the inclined lower surface 18b acts as a support surface for the blade root portion 22 to rebuild the support required for the blade root portion 22 to withstand centrifugal force.

[0071] If necessary, the surface of the inclined portion of the lower surface 19b of the locking member 19 that contacts the blade root portion 22 can be adjusted (especially increased) to reduce the caulking pressure.

[0072] Each locking member 19 also includes a tab 19c extending from the upper surface 19a of the locking member and configured to radially abut against the radial surface of the shoulder 10. The tab 19c allows for fixing the angular position of the locking member 19 relative to the pitch axis Y of the blade 7 and for withstanding lateral forces applied to the locking member 19 by the blade root portion 22. Sliding adjustment between the locking member 19 and the attachment member 9 facilitates installation.

[0073] The locking component 19 is preferably made of metal, such as martensitic steel, aluminum or titanium.

[0074] exist Figure 8 In the illustrated embodiment, the shoulder includes a recess 18 formed in the lower surface 10a of the shoulder, which is configured to receive the associated locking member 19. This recess 18 also allows for a reduction in the radial dimension of the locking member 19 (i.e., the dimension of the locking member in a plane perpendicular to the pitch axis Y) by bringing the radially adjacent portion of the locking member 19 closer to the pitch axis Y. As explained below, this gain in the radial dimension of the locking member 19 allows for a reduction in the structural member 17 made of composite material relative to the attachment member 9 during step S4, so that the locking member can be arranged in the cavity 28, or, if desired, for such arrangement.

[0075] The fan blade 7 also includes a cover 31, which can be secured to the attachment member 9 at the second opening 30, such that the blade root portion 22 is compressed between the cover 31 and the locking member 19. Therefore, the cover 31 applies a restraining force to the blade root portion 22, pressing the blade root portion 22 against the locking member 19 and pressing the locking member 19 against the shoulder 10, thus avoiding the risk of blade root rotation.

[0076] When the second opening 30 is circular, the cover 31 can be secured by screwing it onto the attachment member 9. If desired, the attachment member 9 may also include a braking device configured to prevent the cover 31 from loosening during operation. For example, the braking device may comprise resin and / or self-locking washers applied to the threads of the second opening 30 and / or the cover 31.

[0077] The cover 31 is preferably made of metal, such as martensitic steel, aluminum or titanium.

[0078] Optionally, the fan blade 7 also includes means configured to form radially abutting portions for the fan blade 7 in regions of the leading and / or trailing edges of the fan blade. These means are located in the attachment member 9 between the two locking members 19.

[0079] For example, the abutment forming device can be obtained by machining the wall 25 of the attachment member 9 and extends integrally between the two segments of the shoulder 10. Alternatively, the abutment forming device may include one or two gaskets disposed in the cavity 28 between the two segments of the shoulder 10.

[0080] The blade 7 also includes a seal 20 disposed in the first opening 29, between the composite material structural member 17 and the edge of the first opening 29 surrounding the composite material structural member 17. The seal 20 allows for filling of the gap remaining at the first opening 29 between the composite material structural member 17 and the attachment member 9.

[0081] The seal may specifically include an elastomeric material, such as at least one of the following: ethylene-propylene copolymer (EP or EPM) and ethylene-propylene-diene terpolymer (EPDM), fluorosilicone (FVMQ) or any other silicone-based elastomer, such as silicone-based vinylmethyl silicone (VMQ).

[0082] Figures 5 to 9 The steps of a method S for manufacturing a fan blade 7 according to a possible embodiment of the present invention are shown.

[0083] This manufacturing method specifically includes: manufacturing fiber reinforcement 33 and injecting the fiber reinforcement with plastic material to obtain fan blade 7. As shown below, the injection step can be performed before the fiber reinforcement 33 is arranged in the attachment part 9. Figure 9 ), or alternatively after arranging the fiber reinforcement in the attachment ( Figure 10 )implement.

[0084] In the first embodiment ( Figure 9 In this process, the fiber reinforcement 33 is manufactured before being arranged in the attachment part 9, and then the fiber reinforcement is bonded to the matrix (plastic material). Advantageously, the resulting fan blade 7 is thus removable, which allows the fan blade to be replaced without damaging the attachment part 9 or removing the entire fan disc.

[0085] Therefore, according to step S1 ( Figure 5 The fiber reinforcement 33 is manufactured by three-dimensional weaving on a jacquard loom. During weaving, bundles of warp yarns C (or warp strands) are deposited in multiple layers, each layer containing hundreds of yarns. Weft yarns T (or weft strands) interweave with the warp yarns C to connect the layers of warp yarns C together.

[0086] In the example shown, the three-dimensional weaving is an "interlocking" weaving. The term "interlocking" refers to a weaving in which each layer of weft yarns connects multiple layers of warp yarns, and all yarns on the same weft column have the same movement on the weaving plane.

[0087] Other known types of three-dimensional knitting can be used, especially those described in document WO 2006 / 136755.

[0088] like Figure 6 As shown, the steps of weaving the original fiber reinforcement 33 (or preform) sequentially include: weaving a temporary fiber reinforcement portion 34 (which will later fall off during the manufacturing process), weaving a blade root fiber reinforcement portion 35 for forming the blade root portion 22, and then weaving a wing fiber reinforcement portion 36 for forming the wing portion 21.

[0089] The temporary fiber reinforcement section 34 is woven by interlacing all the warp strands C required to manufacture the fiber reinforcement section 33. Once the weft strands reach a predetermined width l, the wing fiber reinforcement section 36 is woven. Thus, the blade root reinforcement section 35 includes warp yarns C extending inside the wing fiber reinforcement section 36.

[0090] like Figure 6 As shown, the blade root fiber reinforcement portion 35 is woven with continuous weft strands T, which have different finenesses that decrease in the weaving direction (indicated by the arrow). In other words, the fineness decreases as the wing fiber reinforcement portion 36 approaches, so that the blade root fiber reinforcement portion 35 has inclined flanks. These inclined flanks then support the inclined lower surface 19b of the locking member 19.

[0091] It should be noted that "fineness" refers to the dimension characterizing the fineness of yarn: fineness is defined as the mass per unit length of yarn. The normalized unit used to measure fineness is tex (weight in grams per 1000 meters of yarn) or decitex (weight in grams per 10,000 meters of yarn). Other units may also be used, such as denier, metric, or even imperial.

[0092] Thus, the fiber reinforcement portion 35 at the blade root has a thickness that decreases as it approaches the fiber reinforcement portion 36 of the wing. The fiber reinforcement portion at the blade root has a thickness e1 at the blade root and a thickness e2 that is less than e1 at the junction with the fiber reinforcement portion 36 of the wing.

[0093] During the weaving process of the fiber reinforcement 33 with varying thickness and width, a fixed number of warp yarns C are not woven, which allows for the definition of the desired continuously variable profile, width, and thickness of the fiber reinforcement 33.

[0094] The warp yarns C and weft yarns T (referred to as "floats") located at the limits of weave quality are also cut to extract fiber reinforcement 33. Figure 8 ).

[0095] The final fiber reinforcement is then obtained by trimming (“contouring”) the preform. Contouring involves cutting a flat preform along the leading, trailing, and tip edges (leaving excess length at these three cuts). Contouring is then performed along the lower guide tube and on the lateral surfaces of the blade root portion.

[0096] In addition, the temporary fiber reinforcement portion 34 is cut for removal. The contouring and cutting of the blade root portion can be performed using pressurized water jet.

[0097] According to step S2, the attachment part 9 is manufactured, for example by machining, to form cavity 28, first opening 29, second opening 30, shoulder 10, and if necessary, to form threads at the second opening 30 so that the cover 31 can be tightened.

[0098] According to step S3, the fiber reinforcement 33 is arranged in a mold having a cavity with the shape of the final molded part (i.e., fan blade 7), and a plastic material (referred to as the "matrix") is injected into the mold to impregnate the entire fiber reinforcement 33. The injection of the plastic material can be performed using RTM or VARRTM injection technology. The injected plastic material is, for example, a thermosetting liquid composition containing an organic precursor of the matrix material. The organic precursor is typically in the form of a polymer (e.g., a resin), which optionally is diluted in a solvent.

[0099] The date of polymerization of the plastic material is determined, for example, by means of crosslinking. For this purpose, a mold is arranged in an oven. The resulting part is then removed from the mold and profiled by machining the leading edge, trailing edge, and tip of the wing to remove excess length and obtain a part with the desired shape, thus satisfying aerodynamic constraints even though the fibers of the reinforcement 33 may retract during the polymerization of the plastic material. The lower portion of the blade is also machined. If necessary, profile machining can be performed at the end of method S.

[0100] The structural component 17 of the blade 7 is formed by impregnating the reinforcement 33, which is a plastic material constituting the matrix 34, with the reinforcement 33 forming the blade 7.

[0101] According to step S4, the structural member 17 made of composite material is arranged in the attachment member 9 through the first opening 29, such that the wing portion (including the wing fiber reinforcement portion 36) is located outside the attachment member 9, extending beyond the first opening 29, and the blade root portion 22 (including the blade root fiber reinforcement portion 35) is located outside the attachment member 9, extending beyond the second opening 30. In other words, the structural member 17 made of composite material, including the fiber reinforcement 33, is inserted into the attachment member 9 through the first opening 29, but the structural member is arranged at a position lower than its final position relative to the attachment member 9, so as to protrude from the second opening 30.

[0102] In this step, the structural component 17 made of composite material is not held in the attachment component 9.

[0103] According to step S5, the locking member 19 is arranged in the cavity 28 such that the upper surface 1a9 of the locking member axially abuts against the lower surface 10b of the shoulder 10, and such that, if necessary, the tab 19c of the locking member radially abuts against the radial surface 10c of the shoulder 10. Thus, the locking member 19 is positioned angularly, axially, and radially in the attachment member 9.

[0104] In particular, by lowering the structural member 17 made of composite material in step S3, the insertion space between the second opening 30 and the blade root portion 22 is freed up, thereby facilitating the introduction of the locking member 19. This introduction is even easier when the recess 8 is formed in the shoulder 10 and the locking member 19 is smaller in the radial direction.

[0105] According to step S6, the structural member 17 made of composite material is reinstalled in the attachment member 9 toward the first opening 29 until the support abuts against the inclined lower surface 19b of the locking member 19.

[0106] If necessary, one or more gaskets may also be inserted into cavity 28 to form a radially adjacent portion for the portion of the blade root reinforcement extending in the leading and / or trailing edge extension of the structural member made of composite material 17.

[0107] Optionally, the remaining gaps in the cavity 28 of the attachment member 9, particularly between the first opening 29 and the shoulder 10 and / or between the locking member 19 and the cover 31, can be filled with foam 40. Thus, foam 40 protects the blade 7 from the ingress of dust, water, ice, etc., and, if necessary, holds the blade 7 in place within the attachment member 9. For this purpose, foam 40 is selected to have a stiffness of approximately several GPa. The foam may, for example, comprise polymethyl methacrylate (PMI).

[0108] According to step S7, the cover 31 is secured to the attachment member at the second opening by compressing the blade root portion 22 between the cover 31 and the locking member 19. Specifically, the cover 31 is secured such that the cover applies a compressive force to the blade root portion 22, which constrains the blade root portion 22 against the locking member 19 and presses the blade root portion against the shoulder 10.

[0109] According to step S8, the seal 20 is inserted into the first opening 29. Of course, it is understood that step S8 can be performed before step S7.

[0110] Second embodiment ( Figure 10 In the process, after the fiber reinforcement is arranged in the attachment part 9, the fiber reinforcement 33 is fixed with a matrix (plastic material).

[0111] Therefore, according to steps S1 and S2 above, the fiber reinforcement is woven and the attachment member 9 is machined. Then, according to steps S4 to S6 and S8 above, the fiber reinforcement 33 is arranged in the attachment member 9, the locking member 19 is arranged against the shoulder 10, the fiber reinforcement 33 is reinstalled and supported against the locking member 19, foam 40 is optionally introduced into the cavity 28 to fill the gap, and the seal 20 is inserted into the first opening 29.

[0112] Therefore, at this stage, the fiber reinforcement 33 has not yet been consolidated, and the cap 31 is not fixed to the second orifice 30. Furthermore, the fiber reinforcement...

[0113] Optionally, in order to hold the fiber reinforcement 33 in proper position within the attachment member 9 and to secure the fiber reinforcement with a plastic material, a temporary member for holding the fiber reinforcement 33 in place can be positioned within the attachment member 9 against the root reinforcement portion 35 (step S9). Furthermore, a temporary protective member can be arranged at the second opening 30 to protect the means for securing the cover 31 and to protect it from being covered by the plastic material.

[0114] Then, according to step S10, the resulting assembly, including fiber reinforcement 33, attachment part 9, optional foam 40, locking part 19, seal 20 and optional temporary part, is arranged in a mold having a cavity with the shape of the final molded part (i.e., fan blade 7).

[0115] According to step S11, plastic material is injected into a mold to impregnate the entire fiber reinforcement 33. The injection of plastic material can be performed according to step S3 described above. The reinforcement 33, impregnated with the plastic material constituting the matrix 34, forms the structural component 17 of the blade 7, which is made of composite material.

[0116] According to step S12, the temporary component is removed by compressing the blade root portion 22 of the composite material structural member 17 between the cover 31 and the locking member 19, and the cover 31 is fixed to the attachment member 9 at the second opening 30. Specifically, the cover 31 is fixed such that it applies a compressive force to the blade root portion 22, which constrains the blade root portion 22 against the locking member 19 and presses the blade root portion against the shoulder 10.

Claims

1. A blade (7) comprising: - a structural piece (17) made of composite material, said structural piece made of composite material comprising a fibrous reinforcement (33) obtained by three-dimensional weaving and a matrix (34) embedding said fibrous reinforcement (33), said structural piece (17) made of composite material comprising a wing portion (21) having an aerodynamic profile and a blade root portion (22); - a blade root attachment part (9) comprising a wall (25) delimiting a cavity (28), a first opening (29) formed in said wall (25) and a second opening (30) located below said blade root portion (22), said second opening being located on an opposite side of said blade root attachment part (9) with respect to said first opening (29), said structural piece (17) made of composite material extending through said first opening (29) so that said wing portion (21) is located outside said blade root attachment part (9) and said blade root portion (22) is located inside said cavity (28), said blade root attachment part (9) further comprising a shoulder (10) extending from said wall (25) into said cavity (28); - two locking parts (19), each locking part (19) having an upper surface (19a) configured to axially abut against said shoulder (10) and a lower surface (19b) inclined with respect to said upper surface (19a) and configured to bear against said blade root portion (22); and - a cover (31) fixed to said blade root attachment part (9) at said second opening (30) so that said blade root portion (22) is compressed between said cover (31) and said locking parts (19), at least one recess (18) is formed in said shoulder (10), each locking part (19) being housed in said at least one recess (18).

2. The vane (7) according to claim 1, wherein Said locking parts (19) bear against said recesses (18).

3. The vane (7) according to claim 1, wherein Said shoulder (10) has a radial surface (10c) extending opposite said blade root portion (22) and each locking part (19) comprises a tab (19c) extending from the upper surface of said locking part, said tab (19c) being configured to radially abut against the radial surface (10c) of said shoulder (10).

4. The vane (7) according to claim 1, wherein Said fibrous reinforcement (33) comprises a wing fibrous reinforcement portion (36) and a blade root fibrous reinforcement portion (35), wherein each blade root fibrous reinforcement portion (35) is woven continuously with said wing fibrous reinforcement portion (36).

5. A method for manufacturing a blade (7) according to any one of claims 1 to 4, said blade comprising a fibrous reinforcement (33) obtained by three-dimensional weaving (SI), said fibrous reinforcement (33) comprising a wing fibrous reinforcement portion (36) and a blade root fibrous reinforcement portion (35), said method comprising the following steps: - providing a structural piece (17) made of composite material, said structural piece made of composite material comprising a fibrous reinforcement (33) obtained by three-dimensional weaving (SI), said fibrous reinforcement (33) comprising a wing fibrous reinforcement portion (36) and a blade root fibrous reinforcement portion (35), - providing a blade root attachment part (9) comprising a wall (25) delimiting a cavity (28), a first opening (29) formed in said wall (25) and a second opening (30) located below said blade root portion (22), said second opening being located on an opposite side of said blade root attachment part (9) with respect to said first opening (29), - providing two locking parts (19), each locking part (19) having an upper surface (19a) configured to axially abut against said shoulder (10) and a lower surface (19b) inclined with respect to said upper surface (19a) and configured to bear against said blade root portion (22), - providing a cover (31) fixed to said blade root attachment part (9) at said second opening (30) so that said blade root portion (22) is compressed between said cover (31) and said locking parts (19), - forming at least one recess (18) in said shoulder (10), each locking part (19) being housed in said at least one recess (18). - manufacturing (S2) said blade root attachment part (9) to form said cavity (28) and said shoulder (10); - arranging (S4) said fiber reinforcement (33) in said blade root attachment part (9) through said first opening (29) so that said wing fiber reinforcement portion (36) is located outside of said blade root attachment part (9) beyond said first opening (29) and so that a portion of said blade root fiber reinforcement portion (35) is located outside of said blade root attachment part (9) beyond said second opening (30); - arranging (S5) said locking part (19) in said cavity so that an upper surface of said locking part axially abuts against said shoulder (10); - arranging (S6) said fiber reinforcement (33) in said blade root attachment part (9) so that said blade root fiber reinforcement portion (35) is located inside of said blade root attachment part (9) and bears against an inclined lower surface of said locking part (19); and - fixing (S7, S12) said cover (31) on said blade root attachment part (9) at said second opening (30) by compressing said blade root portion (22) between said cover (31) and said locking part (19).

6. The method according to claim 5, further comprising a step (S3) of arranging said fiber reinforcement in a mold and, before the arranging step (S3), a step of injecting a plastic material into said mold to form said structural piece (17) made of composite material comprising said fiber reinforcement (33) and a matrix (34) embedding said fiber reinforcement (33).

7. The method according to claim 6, further comprising a step (S10) of arranging an assembly formed by said fiber reinforcement (33), said blade root attachment part (9) and said locking part (19) in a mold and, before the step (S12) of fixing said cover (31), a step (S11) of injecting a plastic material into said mold to form said structural piece (17) made of composite material comprising said fiber reinforcement (33) and a matrix (34) embedding said fiber reinforcement (33).

8. The method according to claim 7, further comprising, before the step (S10) of arranging said assembly in a mold, a step (S9) of arranging a temporary protection against said blade root fiber reinforcement portion (35) and / or at said second opening (30) and, before the step (S12) of fixing said cover (31), a step of taking out said temporary protection.

9. A gas turbine engine (1) comprising a fan, the fan comprising a hub (6) and blades (7) extending radially from the hub (6), the blades (7) being according to any one of claims 1 to 4, each blade (7) being mounted for rotation about a respective pitch axis (Y) relative to the hub (6), the gas turbine engine (1) further comprising an actuation mechanism (8) controllable to rotate the blades (7) about the pitch axes (Y) of the blades, thereby varying the pitch angle of the blades (7).

10. An aircraft comprising a gas turbine engine (1) according to claim 9.

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