阅读说明：本技术 集成大间隙的复合材料鼓风机叶片 (large-clearance integrated composite material blower blade ) 是由 G·德斯皮耶格勒 于 2019-06-05 设计创作，主要内容包括：本发明提出一种用于涡轮发动机(1)的鼓风机(2)的复合材料叶片(21),叶片(21)的特征在于,它包括延伸到叶片(21)的根部(21d)并且由第一材料制成的第一部分(22),该第一材料包括由第一基质致密化的第一纤维加强件,叶片(21)也包括延伸到叶片(21)的尖端(21c)并且由第二材料制成的第二部分(23),第二材料与第一材料不同并且包括由第二基质致密化的第二纤维加强件,第二材料拥有劣于第一材料的耐磨性。(The invention proposes a composite blade (21) for a blower (2) of a turbine engine (1), the blade (21) being characterized in that it comprises a first portion (22) extending to a root (21d) of the blade (21) and made of a first material comprising a first fibrous reinforcement densified by a first matrix, the blade (21) also comprising a second portion (23) extending to a tip (21c) of the blade (21) and made of a second material, different from the first material and comprising a second fibrous reinforcement densified by a second matrix, the second material possessing a wear resistance inferior to the first material.)

1. A composite blade (21) for a blower (2) of a turbine engine (1), the blade (21) being characterized in that it comprises a first portion (22) extending to a root (21d) of the blade (21) and made of a first material comprising a first fibrous reinforcement densified by a first matrix, the blade (21) also comprising a second portion (23) extending to a tip (21c) of the blade (21) and made of a second material, different from the first material and comprising a second fibrous reinforcement densified by a second matrix, the second material possessing a wear resistance inferior to the first material.

2. A blade (21) according to claim 1, characterized in that the first and second fibre reinforcement are made of a single fibre preform (6), the first and second matrix having different compositions, and the second matrix having a wear resistance inferior to the first matrix.

3. A blade (21) according to claim 1, characterized in that the first fibre reinforcement is made of fibre preform (6') and the second fibre reinforcement is made of short fibres.

4. a blade (21) according to claim 3, wherein the first matrix and the second matrix have the same composition.

5. A blade (21) according to claim 3, characterized in that the first matrix and the second matrix have different compositions, the second matrix having a lower wear resistance than the first matrix.

6. blade (21) according to any of the claims 1 to 5, characterized in that the second portion (23) has a height (H) at the blade (21)₂₁) And preferably a height (H) in the range of 1% to 10% of the height of the blade, and preferably in the range of 2% to 5% of the height of the blade₂₃)。

7. turbine engine (1) with a blower (2) comprising a blade (21) according to any one of claims 1 to 6.

8. The turbine engine (1) of claim 7, characterized in that the turbine engine (1) has a blower housing (4) with an inner annular surface that possesses a better wear resistance than the second material.

9. the turbine engine (1) according to claim 7 or 8, characterized in that the blower (2) is driven in rotation by a shaft (3), the shaft (3) being fixed to the turbine engine (1) by a main bearing, and the shaft (3) also being fixed to the turbine engine (1) by a splitter bearing having a breaking limit smaller than the main bearing.

10. Method of manufacturing a blade (21) according to any of claims 1 to 6, comprising the steps of:

- (E1) making a first portion (22) of the blade (21), which extends to the root (21d) of the blade (21) and is made of a first material comprising a first fibrous reinforcement densified by a first matrix; and

-manufacturing a second portion (23) of the blade (21), which extends to the tip (21c) of the blade (21) and is made of a second material comprising a second fibrous reinforcement densified by a second matrix, the second material possessing a lower wear resistance than the first material (E2).

11. the method according to claim 10, wherein the first portion (22) is produced by densifying the first matrix in a first region (61) of a fiber preform (6) forming the first fiber reinforcement, the first region (61) extending to a first end (6a) of the fiber preform (6) corresponding to a root (21d) of the blade (21), and wherein the second portion (23) is produced by densifying a second region (62) of the fiber preform (6) forming the second fiber reinforcement using the second matrix, the second region (62) extending to a second end (6b) of the fiber preform (6) corresponding to a tip (21c) of the blade (21), the first and second matrices having different compositions, the second matrix possesses a lower wear resistance than the first matrix.

12. The method according to claim 11, characterized in that the fiber preform (6) is densified over its entire length by a first matrix, then the first matrix is eliminated in the second region (62) of the fiber preform (6), and then after the elimination of the first matrix, the second region (62) of the fiber preform (6) is densified with the second matrix.

13. A method according to claim 10, wherein the first portion (22) is manufactured by densifying a fibre preform (6') over its entire length with the first matrix, the fibre preform (6') forming a first fibre reinforcement, and wherein the second portion (23) is manufactured by moulding a second matrix with short fibres dispersed therein to form a second fibre reinforcement onto one end of the fibre preform (6 ').

14. the method of claim 13, wherein the first matrix and the second matrix have the same composition.

15. The method of claim 13, wherein the first matrix and the second matrix have different compositions, and the second matrix has a lower abrasion resistance than the first matrix.

Technical Field

The present invention relates to the general field of aircraft turbine engines, and more specifically to blowers for aircraft turbine engines.

background

As shown in fig. 1, an aircraft turbine engine 1 'comprises a blower 2', the blower 2 'being a large diameter propeller located at the inlet of the turbine engine and driven in rotation by the low pressure shaft of said turbine engine 1'.

In case of loss of the blades 21 'of the blower 2', for example due to foreign objects hitting said blower 2', a separator is generally provided on the blower shaft 3' in order to limit the mechanical loads caused by the unbalance caused by the rotation of the blower 2 'when the blades 21' are lost. The separator is a sacrificial bearing for fixing the blower shaft 3' and is designed to break when the mechanical load becomes excessive, in order to allow the eccentric movement of the blower shaft 3', thereby limiting the mechanical stresses exerted on the blower shaft 3' and transmitted to the load carrying structures of the turbine engine.

therefore, in order to enable the blower 2' to continue to rotate such that the turbine engine 1' continues to rotate when the blower shaft 3' is eccentric, a weakened area 4', called "large clearance", is provided in the inner contour of the blower housing 5 '. This weakened area or large gap 4' is configured to disappear upon contact with the blade 21', thereby allowing the blade 21' to continue to rotate. This large gap 4' also forms a region where the turbine engine cannot contain equipment, since any equipment located in the large gap 4' is at risk of being hit by the blades 21 '.

Document EP 1312762 in the name of the inventor describes a blower blade comprising a weakened region at its tip, which is adapted to break when the tip of the blade hits the blower housing. This solution makes it possible to reduce the thickness of the blower housing and to increase the diameter of the blower.

However, the solution described in document EP 1312762 is complex to perform, has a negative effect on the surface condition of the blade, and is not suitable for blower blades made of fiber-reinforced composite materials.

Disclosure of Invention

The main object of the present invention is therefore to alleviate such drawbacks by proposing a blower.

In a first aspect, the invention proposes a composite blade for a blower of a turbine engine, the blade being characterized in that it comprises a first portion extending to the root of the blade and made of a first material comprising a first fibrous reinforcement densified by a first matrix, the blade also comprising a second portion extending to the tip of the blade and made of a second material, different from the first material and comprising a second fibrous reinforcement densified by a second matrix, the second material possessing a wear resistance inferior to that of the first material.

Such a fan blade thus comprises a layer of sacrificial material formed by the second portion at its tip and which is configured to be removed in contact with the blower housing, thereby forming a large gap. The removal of the layer of sacrificial material at the blade tip takes place by very rapid wear of the layer of sacrificial material or by its decomposition.

The fact that the matrix of the blade at its tip is made of a second material, which is more brittle than the first material, enables the blower blade to be made of a fibre-reinforced composite material, the blower blade having a sacrificial region at its tip in order to form a large gap.

Furthermore, the fact that the large gap is formed by a matrix reinforced by fibrous reinforcements ensures good mechanical strength of the large gap with respect to the stresses to which the outer annular end of the wing is subjected.

The blade may also include the following features:

The first and second fibrous reinforcements are made of a single fibrous preform, the first and second matrices having different compositions, and the second matrix having a lower wear resistance than the first matrix;

The first fibre reinforcement is made of fibre preforms and the second fibre reinforcement is made of short fibres;

-the first matrix and the second matrix have the same composition;

The first matrix and the second matrix have different compositions, the second matrix having a wear resistance inferior to that of the first matrix;

The tip of the blade is covered with a third layer of material, which possesses a lower wear resistance than the second material; and

The height of the second portion is in the range of 1% to 10% of the blade height, and preferably in the range of 2% to 5% of the blade height.

in a second aspect, the invention proposes a blade comprising any one of the above features.

the turbine engine may also include the following features:

the turbine engine has a blower housing with an inner annular surface for wear resistance better than the second material; and

The blower is driven in rotation by a shaft, which is fixed to the turbine engine by a main bearing, and which is also fixed to the turbine engine by a splitter bearing having a breaking limit smaller than the main bearing.

in a third aspect, the invention proposes a method intended for a blade according to any one of the above-mentioned features, comprising the steps of:

-manufacturing a first part of the blade, which first part extends to the root of the blade and is made of a first material comprising a first fibre reinforcement densified by a first matrix; and

-manufacturing a second part of the blade, which second part extends to the tip of the blade and is made of a second material comprising second fiber reinforcements densified by a second matrix, which second material possesses a lower wear resistance than the first material.

The method may also comprise the following features, either individually or in combination, depending on the technical feasibility:

-producing a first portion by densifying a first matrix in a first region of the fiber preform forming the first fiber reinforcement, the first region extending to a first end of the fiber preform corresponding to the root of the blade, and producing a second portion by densifying a second region of the fiber preform forming the second fiber reinforcement using a second matrix, the second region extending to a second end of the fiber preform corresponding to the tip of the blade, the first and second matrices having different compositions, the second matrix having a wear resistance inferior to the first matrix;

-the fiber preform is densified over its entire length by the first matrix, then the first matrix is eliminated over a second region of the fiber preform, and then, after the elimination of the first matrix, the second region of the fiber preform is densified with the second matrix;

-a first portion is produced by densifying a fiber preform with a first matrix over its entire length, the fiber preform forming a first fiber reinforcement, and a second portion is produced by molding a second matrix with short fibers dispersed therein to form a second fiber reinforcement onto one end of the fiber preform;

-the first matrix and the second matrix have the same composition;

The first matrix and the second matrix have different compositions, the second matrix having a wear resistance inferior to that of the first matrix;

-a third layer of material possessing a lower wear resistance than the second material is deposited on the tip of the blade.

drawings

further features and advantages of the invention emerge from the following description with reference to the accompanying drawings, which show embodiments with non-limiting characteristics. In the drawings:

FIG. 1 is a schematic cross-sectional view of a prior art blower;

FIG. 2 is a schematic cross-sectional view of a blower in an embodiment in accordance with the invention;

FIG. 3A is a schematic front view of the blower of FIG. 2 during normal operation of the turbine engine;

FIG. 3B is a schematic front view of the blower of FIG. 2 with the blower off-center;

FIG. 4 illustrates a blade in one possible embodiment of the invention;

FIG. 5 is a chart illustrating steps of a method of manufacturing a blade of the present invention;

Fig. 6A shows a first step in a first variant of the method of manufacturing a blade in a possible embodiment of the invention;

Fig. 6B shows a second step in a first variant of the method of manufacturing a blade in a possible embodiment of the invention;

Fig. 6C shows a third step in a first variant of the method of manufacturing a blade in a possible embodiment of the invention;

FIG. 6D shows a fourth step in a first variation of a method of manufacturing a blade in a possible embodiment of the invention;

FIG. 6E shows a fifth step in a first variation of a method of manufacturing a blade in a possible embodiment of the invention;

Fig. 6F shows a sixth step in a first variant of the method of manufacturing a blade in a possible embodiment of the invention;

FIG. 6G shows a seventh step in a first variation of a method of manufacturing a blade in a possible embodiment of the invention;

Fig. 7A shows a first step in a second variant of the method of manufacturing a blade in a possible embodiment of the invention;

fig. 7B shows a second step in a second variant of the method of manufacturing a blade in a possible embodiment of the invention;

Fig. 7C shows a third step in a second variant of the method of manufacturing a blade in a possible embodiment of the invention;

FIG. 7D shows a fourth step in a second variation of the method of manufacturing a blade in a possible embodiment of the invention; and

Fig. 7E shows a fifth step in a second variant of the method of manufacturing a blade in a possible embodiment of the invention.

Detailed Description

As shown in fig. 2, 3A and 3B, the turbine engine 1 has a blower 2 including a plurality of blades 21. For the sake of simplicity, a single blade 21 is shown in the figures. The blower 2 is driven in rotation about the axis Δ of the turbine engine 1 by a blower shaft 3. The blower shaft 3 may be constituted by a low pressure shaft of the turbine engine 1, or the blower shaft 3 may be driven in rotation by the low pressure shaft via a reduction gear.

The blower shaft 3 is fixed by bearings to the rest of the turbine engine 1 to allow rotation of said blower shaft. Among the bearings fixing the blower shaft 3, the turbine engine comprises at least one main bearing and at least one separator bearing having a breaking limit lower than the limit of the at least one main bearing. The or each splitter bearing thus acts as a sacrificial bearing by breaking under the action of the imbalance caused by the loss of the vanes 21.

The blower 2 is surrounded over its entire contour by a blower housing 4. The housing 4 is an annular portion centered on the axis Δ of the turbine engine. The diameter of the inner annular surface of the blower housing 4 is almost equal to the diameter of the blower 2, thereby reducing parasitic flow between the blower 2 and the blower housing 4. The blower housing 4 may be a component made of metal or ceramic.

The blades 21 of the blower 2 are made of a composite material comprising fibres densified by an organic matrix, for example carbon fibres. The fibers are woven, which may be a three-dimensional weave. The terms "three-dimensional weaving" or "3D weaving" or indeed "multilayer weaving" are used herein to denote a weaving technique in which at least some of the weft yarns are interconnected with a covering yarn over a plurality of covering layers, or vice versa, wherein the weaving is performed using a weave that can be chosen in particular from the following weaves: interlocking, multiple plain, multiple satin, and multiple twill.

each blade 21 has a leading edge 21a, a trailing edge 21b, a tip 21c and a root 21 d. The tip 21c of the blade 21 is the end thereof located radially further from the axis Δ and facing the blower housing 4, while the root 21d of the blade 21 is the end thereof located radially closer to said axis Δ and fastened to the blower hub 20.

The blade 21 comprises a first portion 22 extending from the root 21d along the main longitudinal direction of the blade 21 and a second portion 23 extending from the tip 21c along said main longitudinal direction of the blade 21. The first portion 22 and the second portion 21 are in contact with each other.

The first portion 22 of each blade 21 is made of a first material comprising a first fiber reinforcement densified by a first matrix, while the second portion 23 of each blade 21 is made of a second material comprising a second fiber reinforcement densified by a second matrix.

The second material of the second part 23 possesses a wear resistance which is inferior to the wear resistance of the first material of the first part 22. After the first and second matrices have been cured, the wear resistance of the first and second materials is considered. The second portion 23 thus constitutes a weakened area forming a large gap, so as to allow the blower 2 to continue rotating even when eccentric with respect to the axis Δ. When the blower 2 is eccentric with respect to the axis Δ, the second portion 22 of each blade 21 rubs against the inner annular surface of the blower housing 4, thereby causing at least some of the second portion 23 to be removed because the inner annular surface of the blower housing 4 possesses a better wear resistance than the second material.

thus, and as shown in fig. 3A, during normal operation of the blower 2, i.e. when the rotation of said blower 2 is about the axis Δ of the turbine engine 1, the second portion 23 of each blade 21 remains at a distance from the blower housing 4 and therefore remains intact. Thus, the diameter of the blower 2 is increased without increasing the diameter of the blower housing 4 as compared to prior art blowers. Therefore, the bypass ratio (BPR) of the turbine engine 1 can be increased without increasing the weight of the turbine engine 1.

As shown in fig. 3B, when the blower 2 loses the blades 21, said blower 2 becomes eccentric with respect to the axis Δ of the turbine engine 1 and the tips 21c of the blades 21 rub against the blower housing 4, causing wear and thus causing the second material of the second portion 23 to be removed.

Since the second material possesses a wear resistance which is inferior to that of the first material, it is ensured that the blade 21 wears in the second portion 23 and that the blade 21 does not break in the first portion 22 when the tip 21c of the blade 21 comes into contact with the blower housing 4 due to the eccentric movement of the blower 2 relative to the axis Δ.

the difference in wear resistance between the first material and the second material may be achieved in various possible embodiments.

In a first possible embodiment the second material of the second portion 23 is weakened by using a first and a second matrix having different compositions, or in other words the first and the second matrix are made of different materials, the second matrix having a wear resistance inferior to the wear resistance of the first matrix.

In the first embodiment, the fiber reinforcement of the first portion 22 and the fiber reinforcement of the second portion 23 are formed using a single woven fiber preform, preferably a fiber preform woven by three-dimensional weaving. The first fibre reinforcement corresponds to the part of the fibre preform located in the root 21d of the blade 22 and the part of the fibre preform located in the first portion 22, while the second fibre reinforcement corresponds to the part of the fibre preform located at the tip 21c of the blade 21, i.e. the part of the fibre preform located in the second portion 23.

In this first embodiment, the first substrate may typically be a resin such as an epoxy resin as is conventionally used to fabricate the substrate of blower blades, while the second substrate may be, for example, a semi-rigid polyurethane resin known as "smooth cast 65D". The woven fiber preform may be made of carbon fibers.

With the first embodiment, and as shown in fig. 3B, when the blower 2 loses the blades 21, the blower 2 becomes eccentric with respect to the axis Δ of the turbine engine 1, and the tips 21c of the blades 21 rub against the blower housing 4, thereby abrading the second matrix of the second material that makes up the second portion 23. Once the second matrix of the second portion 23 of the blade 21 has been at least partially eliminated, the second fiber reinforcement, which was initially densified by the second matrix, is exposed and rubs against the blower housing 4, thereby limiting parasitic flow between the tip 21c of the blade 21 and the blower housing 4.

In a second embodiment, the difference in wear resistance between the first material and the second material is achieved by acting on the first fibre reinforcement and on the second fibre reinforcement.

in this second embodiment, the first fibrous reinforcement is constituted by a woven fibrous preform embedded in a first matrix, preferably a fibrous preform woven using three-dimensional weaving, while the second fibrous reinforcement is formed by short fibers embedded in a second matrix.

The staple fibers have a length in the range of 50 micrometers (μm) to 5000 micrometers, or more preferably in the range of 100 micrometers to 300 micrometers.

The fibre preforms forming the first fibre reinforcement and the short fibres forming the second fibre reinforcement may for example be carbon fibres.

The second embodiment provides the advantage of providing a greater difference in wear resistance between the first material and the second material than in the first embodiment, since the reinforcing fibres play a major role in providing wear resistance.

The first and second substrates may have the same composition, in other words, the first and second substrates may be made of the same material, thereby simplifying the manufacturing of the blade 21. The first substrate and the second substrate in the second embodiment may be the same as the first substrate in the first embodiment.

However, the first matrix and the second matrix may have different compositions, the second matrix possessing a wear resistance inferior to the first matrix in order to further reduce the wear resistance of the second portion 23. The first substrate of the second embodiment may be the same as the first substrate of the first embodiment, and the second substrate of the second embodiment may be the same as the second substrate of the first embodiment.

As shown in fig. 4, the blades 21 have a major long axis θ perpendicular to the axis Δ of the turbine engine 1. The blade 21 has an overall height H corresponding to the dimension of the blade 21 along its major longitudinal direction θ₂₁. The first portion 22 has a first height H₂₂The second portion 23 having a second height H₂₃. First height H₂₂can be in the total height H₂₁in the range of 90% to 99%, and a second height H₂₃May be in the range of 1% to 10%. Second height H of second portion 23₂₃Preferably over the total height H of the blade 21₂₁In the range of 2% to 5%. First height H₂₂And a second height H of the second portion 23₂₃Such a ratio allows the blower 2 to be significantly offset to minimize the imbalance caused by the loss of the vanes 21.

in a possible embodiment, the tip 21c of the blade 21 may be covered by a layer 24 of a third material having a wear resistance inferior to that of the second material. This layer 24 forms a wear layer configured to be worn away by abrasion when in contact with the blower housing 4. The layer 24 is eroded by the tip of the blade 21 in contact with the blower housing 4, thereby limiting the amount of space between the tip of the blade 21 and the blower housing 4 as much as possible. In this embodiment, the second portion 23 is located between the first portion 22 and the layer 24 and it is in contact with said second portion 22 and with the layer 24. Such an embodiment provides the advantage of limiting the amount of wear resistant material (third material) used, thereby reducing the weight of the turbine engine 1. In case the blower 2 becomes eccentric due to loss of the blades 21, the layer 24 is eliminated together with the second part 23.

in another embodiment, the inner annular surface of the blower housing 4 is covered by a layer of a first material forming a wear resistant layer which will be worn away when in contact with the second material of the matrix of the second portion 23 at the tip 21c of the blade 21. In case the blades 21 are lost and the blower 2 becomes eccentric, this wear layer is eliminated by rubbing against the second portion 23 of the blades 21. Thereafter, once the wear layer has been removed, the matrix of the second portion 23 is removed again when said second portion 23 is in contact with the inner annular surface of the blower housing 4.

As shown in fig. 5, in a possible embodiment, the blade 21 of the invention is manufactured using a manufacturing method comprising the following steps:

e1, manufacturing a first portion 22 of the blade 21, which extends to the root 21d of the blade 21 and is made of a first material comprising a first fiber reinforcement densified by a first matrix; and

E2 manufacturing a second part 23 of the blade 21, which extends to the tip 21c of the blade 21 and is made of a second material comprising second fibrous reinforcements densified by a second matrix, the second material possessing a lower wear resistance than the first material.

Several variations are possible for manufacturing the first part 22 and the second part 23.

In a first possible manufacturing variant, as shown in fig. 6A for manufacturing the blade 21 of the first embodiment, the first portion 22 is manufactured by densifying a first region 61 of the woven fibrous preform 6, while the second portion 23 is manufactured by densifying a second region 62 of the woven preform 6. A first region 61 of the fibrous preform 6 is located at a first end 6a of said preform 6, while a second region 62 of the fibrous preform 6 is located at a second end 6b of said preform 6, the second end 6b being opposite to the first end 6 a. The first end 6a corresponds to the root 21d of the blade 21, while the second end 6b corresponds to the tip 21c of the blade 21.

The first region 61 of the fiber preform 6 is densified by the first matrix, the first region 61 of the fiber preform 6 forming a first reinforcement of the first material. A second region 62 of the fiber preform is densified by the second matrix, the second region 62 of the fiber preform forming a second reinforcement of the second material. The first matrix and the second matrix are different in composition, and the second matrix has a wear resistance inferior to the first matrix.

In a first possible implementation form of the first variant of the method of manufacturing the blade 21, as shown in fig. 6A-6G, the manufacturing method may comprise the following steps:

the fiber preform 6 is for example made by 3D weaving of fibers, as shown in fig. 6A.

Thereafter, the entire length of the fiber preform 6 is densified with the first matrix, as shown in fig. 6B. For this purpose, the entire fiber preform is placed in a first mold 7, into which a material that is a precursor of the first matrix is injected and polymerized.

After the fiber preform 6 has been densified with the first matrix, a blade 21 is obtained with a fiber reinforcement, preferably a 3D braided reinforcement, that is fully densified with the first matrix, as shown in fig. 6C.

Then, the first matrix is eliminated from the second portion 23 of the blade 21. To this end, the second portion 23 of the blade 21 extending from the tip 21c of the blade 21 is immersed in the tank 8, the tank 8 containing a liquid in which the first matrix is dissolved, as shown in fig. 6D. The first portion 22 of the vane 21 remains outside the slot 8.

after eliminating the first matrix in the second portion 23 of the blade 21, the fibrous preform 6 is bare on said second portion 23, as shown in fig. 6E.

thereafter, the fiber preform 6 is densified with the second matrix on the second portion 23 of the blade 21. To this end, and as shown in fig. 6F, the second portion 23 of the blade 21 is placed in the second mould 9, the material being a precursor of the second matrix is injected into the fibre preform 6 and then polymerised.

As shown in fig. 6G, after the second portion 23 of the blade 21 has been densified with the second matrix, the blade 21 comprises a first portion 22 having the first matrix and a second portion 23 having the second matrix, the second matrix possessing inferior wear resistance to the first matrix.

In another possible variant, the fibrous preform 6 is densified with the first matrix only in the first portion 22, and the method does not have the step of eliminating the first matrix on the second portion 23. For this purpose, only a first region 61 of the fiber preform 6 is mounted in the first mold 7 to be densified with the first material, a second region 62 remaining outside said first mold 7.

in a second possible manufacturing variant for manufacturing the blade 21 of the second embodiment, and as shown in fig. 7A-7E, the first portion 22 of the blade 21 is manufactured by densifying the fiber preform 6' over its entire length. The fiber preform 6' is densified with a first matrix. The densified fiber preform 6' forms only a first fiber reinforcement of the first material for the first portion 22 of the blade 21.

the fiber preform 6' is manufactured, for example, by 3D weaving fibers, as shown in fig. 7A. Thereafter, the fiber preform 6' is densified throughout its length with the first matrix, as shown in fig. 7B. For this purpose, the entire fiber preform 6 'is placed in a first mold 7', into which a material that is a precursor of the first matrix is injected and polymerized. The final part is shown in fig. 7C and corresponds to a first portion 22 of blade 21, first portion 22 forming a bottom portion of said blade 21 extending to a root 21d of said blade 21.

Thereafter, a second part 23 of the blade 21 is manufactured by moulding a second matrix with short fibres distributed therein to form a second fibre reinforcement, the second matrix being moulded onto one end of the fibre preform 6'. This step is illustrated in fig. 7D, in which the moulding of the second portion 23 is carried out by the mould M. After the step of moulding a second matrix with short fibres dispersed therein to form a second fibre reinforcement, the final blade 21 has both a first portion 22 of a first material at the root 21d of the blade 21 and a second portion of a second material at the tip 21c of the blade 21, as shown in fig. 7E.

Furthermore, in a possible variant, the third layer of material 24 may be deposited on the tip 21c of the blade 21, above the second portion 23.