Blade or guide vane with root made by crossing weft yarns

Abstract

The invention relates to a method for manufacturing a propeller blade or vane made of a composite material, comprising:-manufacturing a single-piece fibrous blank (100) comprising an airfoil portion (111) and a root portion (112) comprising a non-woven body (120) by three-dimensional weaving between warp threads (101) and weft threads (102), the root portion (112) comprises at least one varying sub-region (Z1b) in which the number of weft yarns crossing on both sides of the non-interwoven body (120) gradually increases from the airfoil portion (111) to the free end of the root portion (112); -shaping the fibrous blank (100) to obtain a fibrous preform (1); -densifying the preform (1) by means of the matrix in order to obtain a propeller blade or guide vane made of a composite material.

Description

Field of the Invention

[0001] The present invention relates to the field of propeller blades or guide vanes for aircraft, such as propeller blades or guide vanes present on turboprop engines. Background Art

[0002] Propeller blades or guide vanes for turboprop engines are generally made of metallic materials. Although propeller blades or guide vanes made of metallic materials have good mechanical strength, they have the drawback of being relatively heavy.

[0003] To obtain lighter propeller blades or guide vanes, it is known that propeller blades or guide vanes can be made of composite materials, that is to say, by manufacturing a structural part with a fiber reinforcement densified by a matrix.

[0004] New generation engines require more compact blade or guide vane roots. This need stems from the need to be able to pivot the blade or guide vane about its vertical axis so as to adapt its incidence to the flight regime. This need combined with the fact that the blade or guide vane must be integrated as low as possible on the disk requires a significant reduction in the volume of the root.

[0005] To this end, the roots of new generation blades or guide vanes have an axisymmetric or substantially axisymmetric shape and reduced dimensions, which are different from the roots of the prior art (for example, the roots described in documents US2013 / 272893 and US2013 / 0017093, which extend over the entire width of the lower part of the blade or guide vane).

[0006] This axisymmetric or quasi-axisymmetric shape is more difficult to manufacture with composite materials, especially when using three-dimensional weaving to form the fiber reinforcement of the blade or guide vane.

[0007] In addition, the mechanical loads to which the new generation roots are subjected impose additional stresses. In fact, in addition to the tensile and bending mechanical loads usually encountered (which are caused by centrifugal force and object impact respectively), since there is no nacelle around the blade or guide vane to regulate the air flow, the new generation roots may be subjected to significant bending vibration loads. To be able to resist this alternating bending moment, a prestress is applied to the roots in the hub, which generates an additional mechanical load in circumferential compression. Summary of the Invention

[0008] Therefore, it is desirable to be able to propose a solution for enabling aircraft propeller blades or guide vanes made of composite materials to withstand various mechanical loads, especially at the level of the roots with reduced dimensions.

[0009] To this end, the present invention provides a method for manufacturing a propeller blade or a guide vane made of a composite material, the propeller blade or the guide vane including a fiber reinforcement densified by a matrix, the method comprising:

[0010] - manufacturing a single-piece fiber blank by three-dimensional weaving between a plurality of warp yarns and a plurality of weft yarns, the fiber blank having a flat shape, wherein the warp yarns extend in a longitudinal direction corresponding to the spanwise direction of the propeller blade or the guide vane to be manufactured, and wherein the weft yarns extend in a transverse direction corresponding to the chordwise direction of the propeller blade or the guide vane to be manufactured, the fiber blank including an airfoil portion and a root portion for respectively forming at least a part of the fiber reinforcement of the airfoil and the root of the propeller blade or the guide vane,

[0011] - shaping the fiber blank to obtain a single-piece fiber preform, the single-piece fiber preform including an airfoil preform formed by the airfoil portion of the fiber blank and a root preform formed by the root portion of the fiber blank,

[0012] - densifying the fiber preform by a matrix to obtain a propeller blade or a guide vane made of a composite material, the propeller blade or the guide vane having a fiber reinforcement constituted by the fiber preform and densified by the matrix; and forming a single piece with an integrated root,

[0013] characterized in that the root portion of the fiber blank includes a first non-interlaced body that defines a first inner shell and extends in the longitudinal direction, the first inner shell opening at the free end of the root portion, and that the root portion includes at least one variable sub-region extending from the airfoil portion, and wherein a plurality of weft yarns located inside the root portion of the fiber blank cross on both sides of the first non-interlaced body in the transverse direction, and the number of weft yarns crossing on both sides of the first non-interlaced body in the transverse direction in the variable sub-region gradually increases from the airfoil portion to the free end of the root portion.

[0014] The "weft yarns located inside the root portion" or "inner weft yarns" refer to weft yarns that do not exist on the surface of the root portion of the fiber blank.

[0015] It is believed that a fiber blank made by three-dimensional weaving may include two-dimensional weaving or other weaving on its surface in a well-known manner to improve its surface condition.

[0016] Crossing the weft yarns at the root level of the fibrous preform can impart a certain circumferential stiffness to the root of the blade. Thus, the root of the blade will be able to resist not only the usual tensile and bending forces, but also circumferential compression.

[0017] Thus, on the one hand, the blade will have a high circumferential stiffness at the level of the root which is highly vulnerable to circumferential compression, while on the other hand, it will have a high transverse stiffness at the level of the airfoil which is hardly subjected to circumferential compression but is subjected to higher bending and tensile stresses.

[0018] More generally, the three-dimensional weaving continuity between the root and the airfoil contributes to the transfer of various forces without creating mechanically weak interfaces. In addition, by gradually reducing the number of crossing weft yarns as approaching the free end of the airfoil portion and away from the root portion, a smooth transition is ensured between the end of the root portion (which will have a high circumferential stiffness) and the airfoil portion (which will have a considerable transverse stiffness).

[0019] According to a specific feature of the present invention, the root portion further includes an end sub-region extending between the free end of the root portion and the variable sub-region, and wherein all the internal weft yarns cross on both sides of the first non-interlaced body along the transverse direction.

[0020] This weaving pattern can make the root of the blade made of the preform very robust by ensuring excellent circumferential stiffness at the level of the end of the root which is most vulnerable to the circumferential compression. Then, the variable sub-region can also achieve a smoother transition between, on the one hand, the end sub-region (wherein the crossing of all the internal yarns can obtain the main circumferential stiffness) and, on the other hand, the airfoil portion (wherein the stiffness is transverse).

[0021] According to a specific feature of the present invention, the airfoil portion of the fibrous preform includes a second non-interlaced body and a third non-interlaced body, and the second non-interlaced body and the third non-interlaced body define second inner shells and third inner shells opening on the same edge of the airfoil portion of the preform along the transverse direction on both sides of the root portion of the fibrous preform.

[0022] These non-interlaced bodies allow instantaneous or lightweight insertion elements to be inserted into the preform in order to obtain lighter propeller blades or guide vane airfoils while having substantially the same mechanical strength. In addition, since the loom for manufacturing the fibrous preform does not allow the manufacture of very thick roots or airfoils, the insertion elements can increase the thickness of the root or the airfoil portion without reducing the volume ratio of the yarns in the regions for bearing high mechanical loads.

[0023] According to a specific feature of the present invention, the first non-interlaced body also extends into the airfoil portion of the fibrous preform.

[0024] Thus, the fibrous preform includes an inner shell present in both the root portion and the airfoil portion. Thus, the insertion element inserted by the first non-interlaced body can also allow an increase in the thickness of the airfoil portion while maintaining a constant warp-to-weft ratio and a high volume ratio of warp yarns in the region of high bending load around the insert. In fact, the loom used to manufacture the fibrous preform does not allow the manufacture of very thick roots or airfoils.

[0025] According to a specific feature of the present invention, in the airfoil portion of the fibrous preform, at most six weft yarns cross on each plane on both sides of the first non-interlaced body along the transverse direction. Preferably, in the airfoil portion of the fibrous preform, only two weft yarns cross on each plane on both sides of the first non-interlaced body along the transverse direction.

[0026] Thus, a blade is obtained that allows the stiffness orientation to evolve very gradually from the end of the root to the tip: the stiffness is mainly circumferential at the blade root, then mixed in the lower portion of the airfoil including the first non-interlaced body, and finally, mainly transverse in the upper portion of the airfoil that does not include the first non-interlaced body. Thus, by means of the transition region in the lower portion of the airfoil including the first non-interlaced body, the transition between the mainly circumferential stiffness of the root and the mainly transverse stiffness of the upper portion of the airfoil is smoother.

[0027] According to a specific feature of the present invention, the fibrous preform is made by three-dimensional braiding with interlocking braids.

[0028] Using three-dimensional braiding with interlocking braids can also reduce the risk of delamination within the blade or propeller.

[0029] It is believed that the fibrous preform made by three-dimensional braiding with interlocking braids can include another braid, such as two-dimensional or multi-satin braid, on its surface to improve its surface condition.

[0030] According to another specific feature of the present invention, the shaping of the fibrous preform is performed by inserting an insertion element into each non-interlaced body of the fibrous preform.

[0031] The present invention also relates to a propeller blade or a guide vane made of a composite material, the propeller blade or the guide vane comprising a fiber reinforcement densified by a matrix, the propeller blade or the guide vane comprising a root and an airfoil along a longitudinal direction, and extending in a transverse direction between a leading edge and a trailing edge, the fiber reinforcement comprising a fiber preform having a one-piece three-dimensional braid between a plurality of warp yarns extending along the longitudinal direction and a plurality of weft yarns extending along the transverse direction, the fiber preform comprising: a root preform of the propeller blade or the guide vane present in the root and an airfoil preform present in the airfoil, the propeller blade or the guide vane being characterized in that the root preform of the fiber preform comprises a first non-interlaced body defining a first inner shell, the first inner shell forming a chamber opening at a free end of the root, and in that the root preform comprises at least one varying portion extending from the airfoil preform, and wherein a plurality of weft yarns located inside the root preform cross on both sides of the first inner shell in the transverse direction, and the number of weft yarns crossing on both sides of the first inner shell in the transverse direction in the varying portion gradually increases from the airfoil preform to the free end of the root preform.

[0032] According to a specific feature of the present invention, the root preform further comprises: an end portion extending between the free end of the root preform and the varying portion, and wherein all the internal weft yarns cross on both sides of the first inner shell in the transverse direction.

[0033] According to a specific feature of the present invention, the airfoil preform of the fiber preform comprises a second non-interlaced body and a third non-interlaced body, the two interlaced bodies defining a second inner shell and a third inner shell opening on the same edge of the airfoil preform on both sides of the root preform in the transverse direction.

[0034] According to another specific feature of the present invention, the first inner shell also extends into the airfoil preform of the fiber preform.

[0035] According to another specific feature of the present invention, in the airfoil preform of the fiber preform, at most six weft yarns cross on both sides of the first inner shell in the transverse direction in each plane. Preferably, in the airfoil preform of the fiber preform, only two weft yarns cross on both sides of the first inner shell in the transverse direction in each plane. Description of the Drawings

[0036] Figure 1 is a schematic diagram illustrating 3D braiding of a fiber blank for manufacturing a blade.

[0037] Figure 2 is Figure 1 a schematic view of a region of a fibrous preform.

[0038] Figure 3 illustrates Figure 2 a fibrous preform woven along cutting plane III-III.

[0039] Figure 4 illustrates Figure 2 a fibrous preform woven along cutting plane IV-IV.

[0040] Figure 5 illustrates Figure 2 a fibrous preform woven along cutting plane V-V.

[0041] Figure 6 illustrates Figure 2 a fibrous preform woven along cutting plane VI-VI.

[0042] Figure 7 is an exploded perspective view showing an injection molding tool according to an embodiment of the present invention and a fiber preform to be obtained from Figures 1 to 6 a fibrous blank placed therein.

[0043] Figure 8 shows Figure 7 the injection molding tool closed in perspective.

[0044] Figure 9 is a cross-sectional view showing a flexible membrane injection molding tool according to an embodiment of the present invention and a fiber preform to be obtained from Figures 1 to 6 a fibrous preform placed therein. DETAILED DESCRIPTION

[0045] The present invention is generally applicable to various types of propeller blades or guide vanes used in aircraft engines. The present invention has advantageous but non-exclusive applications in large propeller blades or guide vanes integrated into pivotable or variable pitch systems.

[0046] Such propeller blades or guide vanes are generally provided with a root having a relatively small volume and good strength against tensile, bending, and circumferential compressive forces. The blades according to the present invention can particularly form the blades of an unducted moving wheel (for example, in an aeroengine of the so-called "open rotor" type).

[0047] In the remainder of this description, exemplary embodiments are described with respect to the blades of a turboprop engine. However, the exemplary embodiments are also applicable to aircraft propeller guide vanes.

[0048] Figure 1 The fibrous blank 100 of the fiber preform 1 for forming a blade to be manufactured is shown very schematically.

[0049] As Figure 1 schematically illustrated therein, the fibrous structure blank 100 is obtained by three - dimensional (3D) weaving in a known manner using a jacquard - type loom, on which a bundle of warp threads 101 or strands has been arranged in multiple layers of several hundred threads per layer, and the warp threads are interlaced by weft threads 102. The fibrous structure blank 100 is woven as a single piece, and the blank extends in a longitudinal direction D corresponding to the spanwise direction of the blade to be manufactured L and extends in a transverse direction D corresponding to the chordwise direction of the blade to be manufactured between a leading edge 100a and a trailing edge 100b. T extends.

[0050] The blank 100 includes an airfoil portion 111, which is for subsequently forming a part of the airfoil of the blade and defines a first face 111e and a second face 111f for respectively forming the outer camber surface and the inner camber surface of the blade. Thus, the airfoil portion 111 extends in the longitudinal direction D L between a lower edge 100c and an upper edge 100d.

[0051] The fibrous blank 100 further includes a root portion 112, which is for subsequently forming a part of the blade root and extends in the longitudinal direction D L outside the airfoil portion 111, reaching the lower edge 102c, and retreats inward from the leading edge 100a and the trailing edge 100b in the transverse direction D. T The lower edge 102c of the root portion 112 corresponds to the free end of the root portion 112.

[0052] Preferably, as shown in the exemplified example, the 3D weaving is "interlocked" weaving. Here, "interlocked" weaving refers to a type of weaving in which each layer of weft threads is interlaced with multiple layers of warp threads, and all the threads in the same weft thread row have the same movement within the weaving plane.

[0053] Other known types of three - dimensional weaving can be used, such as those described in particular in document WO 2006 / 136755. In particular, this document describes the manufacture of an enhanced fibrous structure for a component such as a blade by weaving into a single piece, which has a first type of core weaving and a second type of skin weaving, which can impart the expected mechanical properties and aerodynamic properties to this type of component.

[0054] The fibrous preform 100 may include a plurality of different types of yarns, in particular ceramic or carbon yarns or mixtures of these yarns. Preferably, the fibrous preform 100 may be made of silicon carbide fibers. Generally, the fibrous preform 100 may also be made of fibers composed of the following materials: alumina, mullite, silica, aluminosilicate, borosilicate, carbon or mixtures of several of these materials.

[0055] When weaving fibrous preforms 100 with different thicknesses and widths, a specific number of warp yarns are not woven, which can define the continuously variable profile and thickness required for the preform 100. An example of varying 3D weaving is described in document US2006 / 257260, in particular such that the thickness between a first edge for forming a leading edge and a second edge with a smaller thickness for forming a trailing edge of the preform 100 can vary. Preferably, the thickness of the trailing edge or leading edge is reduced by withdrawing the weft yarn layer present inside rather than outside the fibrous preform, in order to maintain the continuity of the weft yarns located on the surface of the fibrous preform. Thus, the final blade will include a fiber reinforcement having a more satisfactory bending stiffness in the transverse direction D T and is thus more advantageous in the event of an impact, for example in the case of a bird strike.

[0056] According to the invention, during the weaving process, at least a first non-interlaced body 120 is formed inside the root portion 112 of the fibrous preform 100. Preferably, three non-interlaced bodies are formed inside the fibrous preform 100. In fact, a second non-interlaced body 110 is made inside the airfoil portion 111 of the fibrous preform 100, and a third non-interlaced body 130 is made inside the airfoil portion 111 of the fibrous preform 100. The three non-interlaced bodies 110, 120 and 130 extend in a plane parallel to the surface of the preform 100. The second non-interlaced body 110 and the third non-interlaced body 130 made inside the airfoil portion 111 are located on both sides of the first non-interlaced body 120 made at least inside the root portion 112. Thus, the second non-interlaced body 110, the first non-interlaced body 120 and the third non-interlaced body 130 are arranged in this order along the transverse direction D T in this order.

[0057] The first non-interlaced body 120 extends in the fibrous preform 100 above a first non-interlaced region defined by a profile 120a. Thus, the first non-interlaced body 120 extends in the root portion 112 above at least a first part of a second non-interlaced region defined by the profile 120a. Thus, the first non-interlaced body 120 extends through the root portion 112 of the preform 100.

[0058] In the root portion 112 of the preform 100, the first non-interlaced body 120 extends in the transverse direction D between the leading edge 100a and the trailing edge 100b Textends. Preferably, the first non-interlaced body 120 extends inwards from the leading edge 100a and the trailing edge 100b, that is to say, the first non-interlaced body 120 does not open onto the leading edge 100a and the trailing edge 100b.

[0059] In the root portion 112 of the preform 100, the first non-interlaced body 120 extends in the longitudinal direction D between the lower edge 100c of the airfoil portion 111 and the lower edge 102c of the root portion L and opens onto the lower edge 102c of the root portion. The first non-interlaced body 120 may extend inwards from the lower edge 100c of the airfoil portion 111, that is to say, it does not open into the airfoil portion 111 of the preform 100.

[0060] However, preferably, the first non-interlaced body 120 also extends into the airfoil portion 111 of the preform 100. Thus, the first non-interlaced body 120 extends into the airfoil portion 111 above a second part of the first non-interlaced region defined by the profile 120a.

[0061] In this case, in the airfoil portion 111, the first non-interlaced body 120 extends in the transverse direction D between the leading edge 100a and the trailing edge 100b T and extends. Preferably, the first non-interlaced body 120 extends inwards from the leading edge 100a and the trailing edge 100b, that is to say, the first non-interlaced member 120 does not open onto the leading edge 100a and the trailing edge 100b. If the first non-interlaced body 120 opens onto the leading edge 100a and / or the trailing edge 100b, then of course it does not deviate from the framework of the present invention. Furthermore, in the airfoil portion 111, the first non-interlaced body 120 extends in the longitudinal direction D between the lower edge 100c and the upper edge 100d L and extends. Obviously, the first non-interlaced body 120 opens onto the lower edge 100c so as to open into the root portion 112. Preferably, the first non-interlaced body 120 extends in the longitudinal direction D L inwards from the upper edge 100d, that is to say, the first non-interlaced body 120 does not open onto the upper edge 100d.

[0062] Thus, as Figure 3 illustrated, the first non-interlaced body 120 locally divides the root portion 112 into two woven portions 112a and 112b, and the two woven portions are arranged on both sides of the first non-interlaced body 120 in the thickness direction of the preform 100 (that is to say, in a direction perpendicular to the transverse direction D T and the longitudinal direction D L ). In the illustrated example, as Figure 5As illustrated, the first non-interlaced body 120 locally divides the airfoil portion 111 into a fifth woven portion 114a and a sixth woven portion 114b, and the two woven portions are arranged on both sides of the first non-interlaced body 120 in the thickness direction of the blank 100 (that is, in a direction perpendicular to the transverse direction D T and the longitudinal direction D L .

[0063] The second non-interlaced body 110 extends into the airfoil portion 111 above the second non-interlaced region defined by the contour 110a. Therefore, the non-interlaced body 110 locally divides the airfoil portion 111 into a first woven portion and a second woven portion. The first woven portion includes a part of the first surface 111e for forming the outer arc surface, and the second woven portion includes a part of the second surface 111f for forming the inner arc surface.

[0064] The second non-interlaced body 110 extends in the transverse direction D T between the leading edge 100a and the trailing edge 100b, and retreats inward from the trailing edge 100b, that is, the second non-interlaced body 110 does not open to the trailing edge 100b. Preferably, the second non-interlaced body 110 extends inward from the leading edge 100a in the transverse direction D T , that is, the second non-interlaced body 110 does not open to the leading edge 100a. Preferably, any point belonging to the second non-interlaced body 110 is closer to the leading edge 100a than the trailing edge 100b in the transverse direction D T .

[0065] In the airfoil portion 111, the second non-interlaced body 110 extends in the longitudinal direction D L between the lower edge 100c and the upper edge 100d. The second non-interlaced body 110 opens to the lower edge 100c, and the second non-interlaced body 110 opens to the lower edge 100c between the leading edge 100a and the joint between the root portion 112 and the airfoil portion 111. Preferably, the second non-interlaced body 110 extends inward from the upper edge 100d in the longitudinal direction D L , that is, the first non-interlaced body 110 does not open to the upper edge 100d.

[0066] Therefore, the second non-interlaced body 110 locally divides the airfoil portion 111 into two woven portions 111a and 111b, and the two woven portions are arranged on both sides of the second non-interlaced body 110 in the thickness direction of the blank 100 (that is, in a direction perpendicular to the transverse direction D T and the longitudinal direction D L .

[0067] The third non-interlacing body 130 extends in the airfoil portion 111 over a third non-interlacing region defined by a contour 130a. Thus, the non-interlacing body 130 locally divides the airfoil portion 111 into a first woven portion and a second woven portion, the first woven portion including a part of the first face 111e for forming the outer arc surface, while the second woven portion includes a part of the second face 111f for forming the inner arc surface.

[0068] The third non-interlacing body 130 extends in the transverse direction D between the leading edge 100a and the trailing edge 100b T and recedes inward from the leading edge 100a, that is to say, the third non-interlacing body 130 does not open onto the leading edge 100a. Preferably, the third non-interlacing body 130 extends T inward from the trailing edge 100b in the transverse direction D, that is to say, the third non-interlacing body 130 does not open onto the trailing edge 100b. Preferably, any point belonging to the third non-interlacing body 130 is T closer to the trailing edge 100b than to the leading edge 100a.

[0069] In the airfoil portion 111, the third non-interlacing body 130 extends in the longitudinal direction D between the lower edge 100c and the upper edge 100d L The third non-interlacing body 130 opens onto the lower edge 100c, and the second non-interlacing body 130 opens onto the lower edge 100c between the trailing edge 100b and the junction between the root portion 112 and the airfoil portion 111. Preferably, the third non-interlacing body 130 extends L inward from the upper edge 100d in the longitudinal direction D, that is to say, the non-interlacing body 110 does not open onto the upper edge 100d.

[0070] Thus, as Figure 5 illustrated, the third non-interlacing body 130 locally divides the airfoil portion 111 into two woven portions 113a and 113b, and the two woven portions are arranged on both sides of the third non-interlacing body 130 in the thickness direction of the blank 100 (that is to say, in a direction perpendicular to the transverse direction D T and the longitudinal direction D L ).

[0071] Preferably, in the airfoil portion 111, the second non-interlacing body 110 and the third non-interlacing body 130 extend L a longer length in the longitudinal direction D than the first non-interlacing body 120.

[0072] Thus, as Figure 2 illustrated, the fiber blank 100 consists of several continuous regions that extend across the entire width of the fiber blank 100 in the transverse direction D T and in the longitudinal direction DL Continuous with each other.

[0073] The first region Z1 of the fibrous preform 100 corresponds to the region of the root portion 112 of the fibrous preform 100. Thus, the first region Z1 extends across the entire width of the root portion 112 of the fibrous preform 100 in the transverse direction D T and extends between the lower edge 102c of the root portion 112 and the lower edge 100c of the airfoil portion 111. Thus, the first region Z1 includes only: the first non-interlaced body 120 as a single non-interlaced body.

[0074] The first region Z1 includes: a first sub-region Z1a called an "end sub-region", which includes the free end of the root portion 112, that is, the first sub-region Z1a extends from the lower edge 102c of the root portion 112. The first region Z1 also includes: a second sub-region Z1b called a "changing sub-region", which extends from the lower edge 100c of the airfoil portion 111. Preferably, the first sub-region Z1a and the second sub-region Z1b are adjacent and follow each other in the longitudinal direction D L each other. Preferably, when the root portion 112 has an hourglass shape as illustrated in Figure 2 the cross-section of the hourglass with the smaller thickness (which corresponds to the neck of the blade root portion 112) forms the demarcation between the first sub-region Z1a and the second sub-region Z1b.

[0075] In the case where the first non-interlaced body 120 also extends into the airfoil portion 111, the second region Z2 corresponds to the region of the guide vane airfoil portion 111 where there are three non-interlaced bodies 110, 120 and 130. Thus, the second region Z2 extends across the entire width of the airfoil portion 111 of the fibrous preform 100 in the transverse direction D T and extends from the lower edge 100c of the airfoil portion 111. Thus, as shown in Figure 2 if present, the second region Z2 includes: the second non-interlaced body 110, the first non-interlaced body 120 and the third non-interlaced body 130.

[0076] The third region Z3 of the fibrous preform 100 corresponds to the region (if such a region exists) of the guide vane airfoil portion 111 where there are two non-interlaced bodies. Preferably, as in Figure 2As illustrated in the example, the third region corresponds to the region where the second non-interlaced body 110 and the third non-interlaced body 130 exist in the guide vane airfoil part 111, and the first non-interlaced body 120 does not extend beyond the first region Z1 or the second region Z2. Of course, if the third region Z3 corresponds to the region where the second non-interlaced body 110 and the first non-interlaced body 120 exist in the guide vane airfoil part 111 or the region where the first non-interlaced body 120 and the third non-interlaced body 130 exist (if such a region exists), it does not deviate from the framework of the present invention.

[0077] The fourth region Z4 of the fibrous preform 100 corresponds to the region where only a single non-interlaced body exists in the guide vane airfoil part 111 (if such a region exists). Preferably, as in the case of the example in Figure 2 the fibrous preform 100 does not include the fourth region Z4. If the fibrous preform 100 includes the fourth region Z4, the fourth region Z4 includes the second non-interlaced body 110 or the third non-interlaced body 130. However, if the fourth region Z4 corresponds to the region where only the first non-interlaced body 120 exists in the guide vane airfoil part 111 (if such a region exists), it does not deviate from the framework of the present invention.

[0078] The fifth region Z5 of the fibrous preform 100 corresponds to the region of the guide vane airfoil part 111 that does not include any non-interlaced bodies. Therefore, the fifth region Z5 extends across the entire width of the airfoil part of the fibrous preform 100 in the transverse direction D T and extends to the upper edge 100d of the airfoil part 111.

[0079] Figures 3 to 6 The interlocked braided 3D braiding pattern of the first preform 100 according to the present invention is schematically shown in. For simplicity of illustration, the number of weft yarns shown is reduced.

[0080] Figure 3 is a partial enlarged view of the warp cross-section in the first sub-region Z1a of the first region Z1 of the fibrous preform 100 ( Figure 2 cross-section III-III in). In this example, the fibrous preform 100 includes: 8 layers of warp yarns 101 extending substantially along the longitudinal direction D L In the interweaving regions 115 and 125 of the root part 112 of the fibrous preform 100, the 8 layers of warp yarns 101 are interwoven by the weft yarns T1 to T8, and the weft yarns T1 to D8 extend substantially along the transverse direction D T and extend.

[0081] The 8 layers of warp yarns 101 are assigned to: the yarn layers of the first group 108 and the yarn layers of the second group 109. The warp yarn layers of the first group 108 and the second group 109 are along the thickness direction (that is, along the direction perpendicular to the transverse direction D T and the longitudinal direction DL are arranged on both sides of the first non-interlaced body 120 in the direction). Thus, the first braided portion 112a of the root portion 112 includes a part of the warp yarns 101 of the first group 108, and the second braided portion 112b of the root portion 112 includes a part of the warp yarns of the second group 109. The warp yarn layers of the first group 108 and the second group 109 are connected in the interlaced regions 115 and 125.

[0082] As Figure 3 illustrated, in the first sub-region Z1a of the first region Z1, all the inner weft yarns T2 to T7 cross on both sides of the first non-interlaced body 120 in the transverse direction. On the other hand, the outer weft yarns T1, T8 (that is, those located on the surface of the fibrous preform 100) do not cross the weft yarns of other layers in order to ensure a better surface condition. Of course, if all the inner and outer weft yarns cross on both sides of the first non-interlaced body 120 in the transverse direction, it will not deviate from the framework of the present invention.

[0083] Therefore, in the first sub-region Z1a of the first region Z1, each inner weft yarn crosses other weft yarns in the first interlaced region 115 and the second interlaced region 125. Thus, all the inner weft yarns deflect at the starting point or upstream of the first non-interlaced body 120 along the transverse direction D T and then deflect again at the exit or downstream of the first non-interlaced body 120 along the transverse direction D T The layer of weft yarns T2 to T4 is interlaced with the warp yarns 101 of the first group 108 in the first interlaced region 115, then interlaced with the warp yarns 101 of the second group 109 in the second braided portion 112b, and finally interlaced with the warp yarns 101 of the first group 108 in the second interlaced region 125. Conversely, the layer of weft yarns T5 to T7 is interlaced with the warp yarns 101 of the second group 109 in the first interlaced region 115, then interlaced with the warp yarns 101 of the first group 108 in the first braided portion 112a, and finally interlaced with the warp yarns 101 of the second group 109 in the second interlaced region 125.

[0084] This crossing of the weft yarns in the root portion 112 improves the retention of the fibrous preform 100 around the first non-interlaced body 120 and subsequently allows excellent circumferential stiffness to be imparted to the blade root.

[0085] The first region Z1 further includes: a second sub-region Z1b extending from the lower edge 100c of the airfoil portion 111. This second sub-region Z1b can achieve the transition between (on the one hand) the first sub-region Z1a and (on the other hand) the airfoil portion, in which all the inner weft yarns cross in the first sub-region Z1a and the percentage of the crossed weft yarns is very small in the airfoil portion. Thus, the second sub-region Z1b has a longitudinal direction D LThe percentage of weft crossings on both sides of the first non-interlaced body 120 changes gradually. More specifically, the second sub-region Z1b has a gradually decreasing percentage of weft crossings from the first sub-region Z1a of the root portion 112 to the airfoil portion 111. Thus, a sudden transition between the root portion 112 and the airfoil portion 111 is avoided. Consequently, a blade is obtained that has a gradually evolving stiffness orientation between the root and the airfoil: the stiffness is strong circumferentially at the end of the blade root, and as it approaches the airfoil portion, the circumferential stiffness becomes smaller and the stiffness in the transverse direction becomes larger. However, compared to the stiffness of the airfoil, the stiffness of the blade root is still greater circumferentially and smaller in the transverse direction. Therefore, the transition between the dominant circumferential stiffness at the root end and the dominant transverse stiffness in the upper part of the airfoil is smoother.

[0086] Figure 4 is a partial enlarged view of the warp cross-section in the second sub-region Z1b of the first region Z1 of the fiber preform 100 ( Figure 2 section IV-IV in). In the second sub-region Z1b of the first region Z1, eight layers of warps 101 pass through the wefts T in the interlaced regions 115 and 125 of the root portion 112 of the fiber preform 100 t1 to T t8 interlace, and the wefts T t1 to T t8 extend substantially along the transverse direction D T .

[0087] As Figure 4 illustrated, in the second sub-region Z1b of the first region Z1, only a part of the inner wefts T t2 to T t7 cross on both sides of the first non-interlaced body 120 along the transverse direction. The outer wefts T t1 and T t8 (that is, those located on the surface of the fiber preform 100) do not cross the wefts of other layers to ensure a better surface condition.

[0088] Therefore, in the second sub-region Z1b of the first region Z1, only a certain percentage of the inner wefts cross the other wefts in the first interlaced region 115 and the second interlaced region 125. Thus, only a part of the inner wefts deflect at the starting point or upstream of the first non-interlaced body 120 along the transverse direction D T and then deflect again at the exit or downstream of the first non-interlaced body 120 along the transverse direction D T .

[0089] Therefore, the wefts T t3 and T t4The layer is interwoven with the warp yarns 101 of the first group 108 in the first interweaving region 115, then with the warp yarns 101 of the second group 109 in the second weaving part 112b, and finally with the warp yarns 101 of the first group 108 in the second interweaving region 125. Conversely, the weft yarn T t5 and T t6 The layer is interwoven with the warp yarns 101 of the second group 109 in the first interweaving region 115, then with the warp yarns 101 of the first group 108 in the first weaving part 112a, and finally with the warp yarns 101 of the second group 109 in the second interweaving region 125. In the Figure 4 example illustrated in, for simplicity of the drawings, only four weft yarns cross on both sides of the first non-interlacing body 120. Preferably, more weft yarns cross on both sides of the first non-interlacing body 120 to ensure sufficient circumferential stiffness in the future blade root.

[0090] Preferably, in the second sub-region Z1b of the first region Z1, the percentage of the internal weft yarns crossing on both sides of the first non-interlacing body 120 gradually changes from 100% at the junction with the first sub-region Z1a to 5% to 30% at the junction with the airfoil part 111.

[0091] Figure 5 is a partial enlarged view of the cross-section of the warp yarns in the second region Z2 of the fibrous preform 100 ( Figure 2 the V-V cross-section in). In the second region Z2, 8 layers of warp yarns 101 are interwoven by the weft yarns T 11 to T 18 in the interweaving regions 105, 115, 125 and 135 of the airfoil part 111 of the fibrous preform 100, and the weft yarns T 11 to T 18 extend substantially along the transverse direction D T .

[0092] The layers of the warp yarns 101 of the first group 108 and the layers of the warp yarns 101 of the second group 109 are arranged on both sides of the second non-interlacing body 110, the first non-interlacing body 120 and the third non-interlacing body 130 in the thickness direction (that is, in a direction perpendicular to the transverse direction D T and the longitudinal direction D L ).

[0093] Therefore, the first weaving part 111a, the third weaving part 113a and the fifth weaving part 114a of the airfoil part 111 respectively include a part of the warp yarns 101 of the first group 108, and the second weaving part 111b, the fourth weaving part 113b and the sixth weaving part 114b of the airfoil part 111 respectively include a part of the warp yarns of the second group 109. The layers of the warp yarns 101 of the first group 108 and the second group 109 are connected in the interweaving regions 105, 115, 125 and 135.

[0094] The first interweaving region 115 separates the second non - interwoven body 110 from the first non - interwoven body 120. The second interweaving region 125 separates the first non - interwoven body 120 from the third non - interwoven body 130. The third interweaving region 105 includes a part of the leading edge 100a. The fourth interweaving region 135 includes a part of the trailing edge 100b. Thus, the third interweaving region 105, the second non - interwoven body 110, the first interweaving region 115, the first non - interwoven body 120, the second interweaving region 125, the third non - interwoven body 130, and the fourth interweaving region 135 are in this order along the transverse direction D T are continuous with each other in the second region Z2.

[0095] As Figure 5 illustrated, only two weft yarns T14, T15 cross in each plane, and these two yarns are located at the core of the airfoil part 111 and are substantially along the transverse direction D along the boundaries of the first non - interwoven body 120, the second non - interwoven body 110, and the third non - interwoven body 130 T through the airfoil part 111. Preferably, at most six weft yarns cross in the second region Z2 preferably along the boundaries of the first non - interwoven body 120, the second non - interwoven body 110, and the third non - interwoven body 130.

[0096] In Figure 5 the illustrated example, for reasons of simplicity, the space between each non - interwoven body 110, 120, 130 is very limited. Preferably, a larger space can be maintained between each non - interwoven body 110, 120, 130 in order to properly perform three - dimensional braiding of the fibers. Additional weft yarns can be inserted into these spaces between the non - interwoven bodies 110, 120, 130 to compensate for the lack of thickness due to the absence of non - interwoven bodies.

[0097] Thus, in the second region Z2, two weft yarns T 14 、T 15 cross at least in the first interweaving region 115 and the second interweaving region 125. Preferably, as Figure 5 illustrated in the example, two weft yarns T 14 、T 15 also cross in the third interweaving region 105 and the fourth interweaving region 135. Thus, two weft yarns T 14 、T 15 are deflected at the starting point or upstream of the first non - interwoven body 120 along the transverse direction D T and then deflected again at the exit or downstream of the first non - interwoven body 120 along the transverse direction D T 。

[0098] Thus, the weft yarns T 11 to T 13Across the entire width of the airfoil portion 111 in the transverse direction D T interlaces with the warp threads 101 of the first group 108. Thus, the weft threads T 11 to T 13 interlace with the warp threads 101 of the first group 108 in the third interlacing region 105, the first knitting portion 111a, the first interlacing region 115, the fifth knitting portion 114a, the second interlacing region 125, the third knitting portion 113a, and the fourth interlacing region 135.

[0099] Conversely, the weft threads T 16 to T 18 across the entire width of the airfoil portion 111 in the transverse direction D T interlace with the warp threads 101 of the second group 109. Thus, the weft threads T 16 to T 18 interlace with the warp threads 101 of the second group 109 in the third interlacing region 105, the second knitting portion 111b, the first interlacing region 115, the sixth knitting portion 114b, the second interlacing region 125, the fourth knitting portion 113b, and the fourth interlacing region 135.

[0100] This partial crossover of the weft threads in the lower part of the airfoil portion 111 improves the retention of the fiber preform 100 around the three non-interlaced bodies 110, 120, and 130, and subsequently enables a smooth transition between the circumferential stiffness at the blade root and the transverse stiffness at the airfoil tip by presenting a hybrid stiffness between the circumferential stiffness and the transverse stiffness.

[0101] Figure 6 is a locally enlarged view of the cross-section of the warp threads in the third region Z3 of the fiber preform 100 ( Figure 2 the VI-VI cross-section in). In the third region Z3, 8 layers of warp threads 101 are interlaced by the weft threads T 21 to T 28 in the interlacing regions 105, 115, 125, and 135 of the airfoil portion 111 of the fiber preform 100, and the weft threads T 21 to T 28 extend substantially in the transverse direction D T .

[0102] The layers of warp threads 101 of the first group 108 and the second group 109 are arranged on both sides of the second non-interlaced body 110 and the third non-interlaced body 130 in the thickness direction (i.e., in a direction perpendicular to the transverse direction D T and the longitudinal direction D L ).

[0103] Thus, the first braided portion 111a and the third braided portion 113a of the airfoil portion 111 each include a part of the warp yarns 101 of the first group 108, and the second braided portion 111b and the fourth braided portion 113b of the airfoil portion 111 each include a part of the warp yarns of the second group 109. The warp yarn layers of the first group 108 and the second group 109 are connected in the interweaving regions 105, 115, 125, and 135.

[0104] The common region of the third interweaving region 105, the second non-interlaced body 110, the first interweaving region 115, and the second interweaving region 125, the third non-interlaced body 130, and the fourth interweaving region 135 are continuous with each other in the lateral direction D in this order. T In the third region Z3.

[0105] As Figure 6 Illustrated in, preferably, there are only two weft yarns T 24 , T 25 Crossing each plane, and these two yarns are located at the core of the airfoil portion 111 and pass through the airfoil portion 111 substantially along the boundary between the second non-interlaced body 110 and the third non-interlaced body 130 in the lateral direction D. T Preferably, there are at most six weft yarns in each plane preferably crossing in the third region Z3 along the boundary between the second non-interlaced body 110 and the third non-interlaced body 130.

[0106] Therefore, as Figure 6 Illustrated in, in the third region Z3, two weft yarns T 14 , T 15 Preferably cross in the third non-interlaced body 105 and cross twice in the common region of the first interweaving region 115 and the second interweaving region 125 and in the fourth interweaving region 135.

[0107] Therefore, two weft yarns T 24 , T 25 Deflect at the starting point or upstream of the second non-interlaced body 110 in the lateral direction D T , and then deflect again at the exit or downstream of the second non-interlaced body 110 in the lateral direction D T , and then deflect at the starting point or downstream of the third non-interlaced body 130 in the lateral direction D T , and then deflect again at the exit or upstream of the third non-interlaced body 130 in the lateral direction D T .

[0108] Therefore, the weft yarns T 21 To T 23 Interlace with the warp yarns 101 of the first group 108 across the entire width of the airfoil portion 111 in the lateral direction D. Therefore, the weft yarns T T 21 ​from T to T 23 interweaves with the warp threads 101 of the first group 108 in the third interweaving region 105, the first braiding part 111a, the first interweaving region 115 and the second interweaving region 125, the third braiding part 113a, and the fourth interweaving region 135.

[0109] Conversely, the weft thread T 26 from T to T 28 extends across the entire width of the airfoil part 111 in the transverse direction D T and interweaves with the warp threads 101 of the second group 109. Thus, the weft thread T 26 from T to T 28 interweaves with the warp threads 101 of the second group 109 in the third interweaving region 105, the second braiding part 111b, the first interweaving region 115 and the second interweaving region 125, the fourth braiding part 113b, and the fourth interweaving region 135.

[0110] This partial crossover of the weft thread in the middle part of the airfoil part 111 improves the retention of the fibrous preform 100 around the two non-interwoven bodies 110 and 130, and subsequently enables a smoother transition between the circumferential stiffness at the blade root and the transverse stiffness at the airfoil tip by presenting a hybrid stiffness between the circumferential stiffness and the transverse stiffness.

[0111] In the fifth region Z5, there is a classical three-dimensional braiding, so it has a main transverse stiffness.

[0112] Once the braiding is completed, the unbraided yarns around the fibrous preform 100 are cut to extract the preform. The second non-interwoven body 110, the first non-interwoven body 120, and the third non-interwoven body 130 respectively form a second inner shell, a first inner shell, and a third inner shell extending into the first fibrous preform 100 in the first fibrous preform 100.

[0113] To form the fibrous preform 1 of the blade to be manufactured, the fibrous preform 100 is shaped. Thus, the airfoil part 111 of the fibrous preform 100 is shaped to form the airfoil preform 11 of the preform 1, and the root part 112 of the fibrous preform 100 is shaped to form the root preform 12 of the preform 1.

[0114] Preferably, the shaping of the fibrous preform 100 is performed by inserting at least one first insertion element 20 into the first non-interwoven body 120. Preferably, one or more second insertion elements 10 and third insertion elements 30 can also be inserted into the airfoil part 111 of the fibrous preform 100 through the second non-interwoven body 110 and the third non-interwoven body 130 respectively. These insertion elements 10, 20, 30 can be used to form part of the final part, or for removal after the densification operation of the fibrous preform 1.

[0115] The insert elements 10, 20, 30 may be made of foam or at least partially have a lattice structure. The insert elements 10, 20, 30 may also be at least partially made of transient materials (i.e., materials that can be removed mechanically, chemically, or thermally).

[0116] The insert elements 10, 20, 30 are preferably made of non-structural materials. The mass density of the insert elements 10, 20, 30 that can be used to form part of the final blade is lower than the mass density of the fiber preform densified in the matrix in the final blade. The insert elements 10, 20, 30 may be made of foam (e.g., polyurethane). The insert elements 10, 20, 30 may be made of honeycomb material.

[0117] The insert elements 10, 20, 30 may be made of the same material. At least one of the insert elements 10, 20, 30 may be made of a material different from another one of the insert elements 10, 20, 30. Preferably, the second insert element 10 and the third insert element 30 for insertion into the second non-interwoven body 110 and the third non-interwoven body 130 are made of the same material, while the first insert element 20 for insertion into the first non-interwoven body 120 is made of a different material.

[0118] The airfoil preform of the obtained fiber preform 1 generally has the shape of the airfoil of the final blade. For example, a compaction step may be performed on the fiber preform 1 to change its thickness in the longitudinal direction.

[0119] Then the fiber preform 1 made as described above is densified. The densification of the fiber preform 1 of the fiber reinforcement for constituting the component to be manufactured includes: filling the pores of all or part of the volume of the preform with the material constituting the matrix.

[0120] This densification can be performed in a liquid process in a manner known per se. The liquid process includes: impregnating the preform with a liquid composition containing a precursor of the matrix material. The precursor is usually in the form of a polymer, such as a high-performance epoxy resin that may be diluted in a solvent. The preform is placed in a mold, and the mold can be sealedly enclosed with a shell having the shape of the final molded blade. Then the mold is closed, and the liquid matrix precursor (e.g., resin) is injected into the entire shell to impregnate the entire fiber part of the preform.

[0121] The conversion of the precursor into the matrix (i.e., its polymerization) is performed by heat treatment (usually by heating the mold) after removing any solvent and polymer crosslinking, and the preform always remains in the mold having a shape corresponding to the shape of the workpiece to be manufactured.

[0122] In the case of forming a carbon or ceramic matrix, the heat treatment comprises: pyrolyzing the precursor to convert the matrix into a carbon or ceramic matrix depending on the precursor used and the pyrolysis conditions. For example, a liquid ceramic precursor (especially SiC) may be a resin of the polycarbosilane (PCS) or polytitanocarbosilane (PTCS) or polysilazane (PSZ) type, while a liquid carbon precursor may be a resin with a relatively high coke content, such as a phenolic resin. Several consecutive cycles from impregnation to heat treatment may be carried out to achieve the desired degree of densification.

[0123] According to one aspect of the invention, especially in the case of forming an organic matrix, the densification of the fiber preform can be carried out by a known transfer molding method called RTM (resin transfer molding). According to this RTM method, the fiber preform is placed in a mold having the external shape of the workpiece to be manufactured. A thermosetting resin is injected into the internal space of the mold including the fiber preform. A pressure gradient is usually established in the internal space between the position where the resin is injected and the resin discharge hole so as to control and optimize the impregnation of the preform with the resin.

[0124] As Figure 7 and Figure 8 illustrated in

[0125] As Figure 8 illustrated in

[0126] here, injecting the liquid matrix precursor composition into the fiber preform and converting it into a matrix is carried out in an injection molding tool 60, which includes a first housing 61 and a second housing 62. The first housing includes a first mold cavity 61a at its center that partially corresponds to the shape and dimensions of the blade to be manufactured. The second housing includes a second mold cavity 62a at its center that partially corresponds to the shape and dimensions of the blade to be manufactured. Once the tool 60 is closed, the corresponding first mold cavity 61a and second mold cavity 62a of the first housing 61 and the second housing 62 jointly define an internal volume that has the shape of the blade to be manufactured and in which the fiber preform 1 is placed. Compaction of the fiber preform can be carried out with the tool 60 closed in order to obtain a defined fiber fraction in the preform. In this case, for example, a compaction pressure is applied to the housings 61 and 62 by a press. Compaction of the fiber preform can also be carried out in a separate mold before being introduced into the injection molding tool.The tool 60 further includes: a device for injecting a liquid matrix precursor and converting the precursor into a matrix. More specifically, in the example described herein, the first housing 61 of the tool 60 includes an injection port 61e for allowing the injection of a liquid matrix precursor composition into the fiber preform, while the second housing includes a discharge port 62s for cooperating with a pumping system for evacuating the tool and removing air during the injection process. The injection tool 60 further includes: a lower part 63 and an upper part 64, between which the first housing 61 and the second housing 62 are placed, and the lower part 63 and the upper part 64 are equipped with heating means ( Figure 8 not shown).

[0127] Once the mold 60 is closed, the blade is molded by impregnating the preform 1 with a thermosetting resin polymerized by heat treatment. For this purpose, an injection or transfer molding method known as RTM (Resin Transfer Molding) is used. According to the RTM method, a resin (e.g., a thermosetting resin) is injected via the injection port 61e of the first housing 61 into the internal volume occupied by the preform 1. The port 62s of the second housing 62 is connected to a discharge conduit ( Figure 8 not shown) maintained under pressure. This configuration allows a pressure gradient to be established between the lower part of the preform 1 (where the resin is injected) and the upper part of the preform 1 (which is near the port 62s). In this way, the resin injected generally at the level of the lower part of the preform 1 will gradually impregnate the entire preform by circulating it upwards to the discharge port 62s (through which the excess resin is discharged). Of course, the first housing 61 and the second housing 62 of the tool 60 may respectively include a plurality of injection ports and a plurality of discharge ports.

[0128] For example, the resin used may be an epoxy resin with a temperature rating of 180 °C (the highest temperature supported without loss of properties). Resins suitable for the RTM method are well known. They preferably have a low viscosity to facilitate their injection into the fibers. The choice of temperature rating and / or the chemical nature of the resin depends on the thermo-mechanical loads that the workpiece must withstand. Once the resin has been injected into the entire reinforcement, it is polymerized by heat treatment according to the RTM method.

[0129] As Figure 9 illustrated, the densification of the fiber preform can also be performed in a well-known manner by membrane injection. This injection mode allows complete control of the amount of resin or slurry injected, thus ensuring an accurate and suitable fiber volume ratio. Consequently, the mechanical properties of the workpieces thus manufactured are improved, with little variation between the workpieces.

[0130] The fiber preform 1 is disposed in a mold 70 which on the one hand includes an impregnation chamber 71 in which the fiber preform is disposed so as to be densified by a matrix by injecting an impregnation fluid through an injection hole 71a, and which on the other hand includes a compaction chamber 72 into which a compression fluid is injected through an injection hole 72a so as to apply pressure to the fiber preform 1 during densification of the fiber preform 1 by the matrix. The impregnation chamber 71 and the compaction chamber 72 are separated by a flexible membrane 73. The membrane 73 can apply pressure to the fiber preform 1 mounted in the impregnation chamber 71, and the compression fluid applies a pressure P to the membrane 73 to deform it, which in turn applies pressure to the fiber preform 1. The flexible membrane 73 is made of silicone resin, for example.

[0131] Depending on the dimensions, thickness and shape of the propeller blade or guide vane to be manufactured, preferably different sequences of compression and impregnation fluid injection are adopted.

[0132] For example, an impregnation fluid (e.g., resin) can first be injected into the impregnation chamber provided with the fiber preform. Once the injection of the impregnation fluid is complete, a compression fluid (e.g., water) is injected into the compaction chamber so as to apply pressure to the flexible membrane. Thus, the flexible membrane applies pressure to the fiber preform, which allows the impregnation fluid to penetrate into the preform.

[0133] Then, the preform is subjected to a heat treatment while maintaining the pressure applied by the membrane in order to form a matrix in the pores of the fiber preform.

[0134] According to another example, the compression fluid can first be injected into the compaction chamber. Thus, even before injecting the impregnation fluid, a pressure whose value allows obtaining the desired fiber volume ratio has been applied to the fiber preform via the flexible membrane. Then, the injection of the impregnation fluid is started, which can be carried out while the compression fluid is still being injected to compensate for pressure losses, especially in the case where the impregnation fluid is a slurry. Such an injection sequence is described, for example, in document WO 2019 / 197757 A1.

[0135] After injection and polymerization, the blade is demolded.

[0136] Preferably, the first insert element 20 is withdrawn to obtain a hollow blade root. The second insert element 10 and the third insert element 30 can also be withdrawn to obtain at least a partially hollow blade airfoil. If an insert element made of a transient material has been inserted into the fiber preform, it can be removed during the resin polymerization process, or during or after the blade demolding process. Finally, one or more insert elements 10, 20, 30 can be retained in the blade.

[0137] The manufactured workpiece can be subjected to trimming or machining steps to obtain the propeller blade or guide vane to be manufactured.

[0138] The above densification method allows the manufacture of propeller blades or guide vanes mainly made of organic matrix composite (OMC) materials, carbon matrix composite (C / C) materials, and ceramic matrix composite (CMC) materials from the fiber preforms of the present invention.

Claims

1. A manufacturing method of a propeller blade or a guide vane made of a composite material, the propeller blade or the guide vane including a fiber reinforcement densified by a matrix, the method comprises: A single-piece fibrous blank (100) is manufactured by three-dimensional weaving between a plurality of warp yarns (101) and a plurality of weft yarns (102), the fibrous blank (100) having a flat shape, wherein the warp yarns (101) extend in a longitudinal direction (D L ) corresponding to the spanwise direction of the propeller blade or guide vane to be manufactured, and wherein the weft yarns (102) extend in a transverse direction (D T ) corresponding to the chordwise direction of the propeller blade or guide vane to be manufactured, the fibrous blank (100) comprising an airfoil portion (111) and a root portion (112), the airfoil portion and the root portion being for respectively forming at least a part of the fibrous reinforcement of the airfoil and the root of the propeller blade or guide vane, shaping the fiber preform (100) to obtain a single-piece fiber preform (1), the single-piece fiber preform including an airfoil preform formed by the airfoil portion (111) of the fiber preform (100) and a root preform formed by the root portion (112) of the fiber preform (100), densifying the fiber preform (1) by a matrix to obtain a propeller blade or a guide vane made of a composite material, the propeller blade or the guide vane having a fiber reinforcement constituted by the fiber preform (1) and densified by the matrix; and forming a single-piece with an integrated root, Characterized in that, the root portion (112) of the fiber blank (100) includes a first non-interlaced body (120), the first non-interlaced body defining a first inner housing and extending along the longitudinal direction (D L ), the first inner housing opening at the free end (102c) of the root portion (112), and wherein, the root portion (112) includes at least one variable sub-region (Z1b) extending from the airfoil portion (111), and wherein, a plurality of weft yarns (T t3 , T t4 , T t5 , T t6 ) located inside the root portion (112) of the fiber blank (100) cross on both sides of the first non-interlaced body (120) along the transverse direction (D T ), and the number of weft yarns crossing on both sides of the first non-interlaced body (120) along the transverse direction (D T ) in the variable sub-region (Z1b) gradually increases from the airfoil portion (111) to the free end (102c) of the root portion (112).

2. The manufacturing method according to claim 1, wherein, The root portion (112) further includes: an end sub-region (Z1a) extending between the free end (102c) of the root portion (112) and the variable sub-region (Z1b), and wherein all the inner weft yarns (T 2 、T 3 、T 4 、T 5 、T 6 、T 7 ) cross on both sides of the first non-interlaced body (120) along the transverse direction (D T ).

3. The manufacturing method according to claim 1 or 2, wherein, The airfoil portion (111) of the fiber preform (100) includes a second non-interlaced body (110) and a third non-interlaced body (130), and the second non-interlaced body and the third non-interlaced body define, along the transverse direction (D T ), second and third inner shells that open on the same edge of the airfoil portion (111) of the fiber preform (100) on both sides of the root portion (112) of the fiber preform (100).

4. The manufacturing method according to any one of claims 1 to 3, wherein, the first non-interlaced body (120) also extends into the airfoil portion (111) of the fiber preform (100).

5. The manufacturing method according to claim 4, wherein, In the airfoil portion (111) of the fibrous preform (100), there are at most six weft yarns (T 14 , T 15 ) crossing on both sides of the first non-interlaced body (120) along the transverse direction (D T ).

6. The manufacturing method according to claim 5, wherein, In the airfoil portion (111) of the fibrous preform (100), only two weft yarns (T 14 , T 15 ) cross on both sides of the first non-interlaced body (120) along the transverse direction (D T ).

7. The manufacturing method according to any one of claims 1 to 6, wherein, the fiber preform (100) is made by three-dimensional weaving with interlocking weaving.

8. The manufacturing method according to any one of claims 1 to 7, wherein, the shaping of the fiber preform (100) is performed by inserting insertion elements (10, 20, 30) into each non-interlaced body (110, 120, 130) of the fiber preform (100).

9. A propeller blade or guide vane made of a composite material, the propeller blade or guide vane comprising a fiber reinforcement densified by a matrix, the propeller blade or guide vane including a root and an airfoil along a longitudinal direction (D L ) and extending in a transverse direction (D T ) between a leading edge and a trailing edge, the fiber reinforcement including a fiber preform (1), the fiber preform having a one-piece three-dimensional braid between a plurality of warp yarns (101) extending along the longitudinal direction (D L ) and a plurality of weft yarns (102) extending along the transverse direction (D T ), the fiber preform (1) comprises: The root preform present in the root of the propeller blade or guide vane and the airfoil preform present in the airfoil, characterized in that the root preform of the fiber preform (1) comprises a first non-interlaced body (120) defining a first inner housing, the first inner housing forming a chamber opening at the free end of the root, and that the root preform comprises at least one varying portion extending from the airfoil preform, and wherein a plurality of weft yarns (T t3 、T t4 、T t5 、T t6 ) cross on both sides of the first inner housing along the transverse direction (D T ), and the number of weft yarns crossing on both sides of the first inner housing along the transverse direction (D T ) in the varying portion gradually increases from the airfoil preform to the free end of the root preform.

10. The propeller blade or the guide vane according to claim 9, wherein, The root preform further comprises: an end portion extending between the free end and the varying portion of the root preform, and wherein all of said inner weft yarns (T 2 、T 3 、T 4 、T 5 、T 6 、T 7 ) cross on both sides of the first inner housing along the transverse direction (D T ).

11. The propeller blade or the guide vane according to claim 9 or 10, wherein, The airfoil preform of the fiber preform (1) includes a second non-interlaced body (110) and a third non-interlaced body (130), and the second non-interlaced body and the third non-interlaced body define, along the transverse direction (D T ) second and third inner shells opening on the same edge of the airfoil preform on both sides of the root preform.

12. The propeller blade or the guide vane according to any one of claims 9 to 11, wherein, the first inner housing also extends into the airfoil preform of the fiber preform (1).

13. The propeller blade or the guide vane according to claim 12, wherein, In the airfoil preform of the fiber preform (1), there are at most six weft yarns (T 14 、T 15 ) crossing on both sides of the first inner housing along the transverse direction (D T ).

14. The propeller blade or the guide vane according to claim 13, wherein, In the airfoil preform of the fiber preform (1), there are only two weft yarns (T 14 , T 15 ) crossing on both sides of the first inner housing along the transverse direction (D T ).

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