EP4330023A1

EP4330023A1 - Device for moulding a bladed part of a turbine engine

Info

Publication number: EP4330023A1
Application number: EP22735514.6A
Authority: EP
Inventors: Maxime Marie Désiré BLAISE; Hubert Jean Marie Fabre; Jeff POTE
Original assignee: Safran Aircraft Engines SAS
Current assignee: Safran Aircraft Engines SAS
Priority date: 2021-04-28
Filing date: 2022-04-22
Publication date: 2024-03-06
Also published as: US20240059032A1; WO2022229547A1

Abstract

The invention relates to a device (30) for moulding at least one bladed part (10) of a turbine engine, comprising: a base (38); a mould (40) formed from a plurality of parts nested inside one another, this mould being applied to the base (38), and first sealing means being mounted between the mould (40) and the base (38); and a bell (42) mounted on the mould (40) and around the mould (40), this bell (42) being applied to the base (38), and second sealing means being mounted between the bell (42) and the base (38), this bell (42) being configured to be held tight against the base (38) and comprising interior surfaces (48a, 48b, 48c, 48d) engaging by wedge effect with complementary exterior surfaces (40a, 40b, 40c, 40d) of the mould (40) in order to apply a clamping force on the parts of this mould.

Description

DESCRIPTION

TITLE: MOLDING DEVICE FOR A BLADED PART OF

TURBOMACHINE

Technical Field of the Invention

The present invention relates to a device for molding a bladed part of a turbomachine, as well as a method using this device.

Technical background

The state of the art includes in particular the documents FR-A1-

2 956057, FR-A1-3014008, FR-A1-3029 134, FR-A1-3032 147, FR-A1-

3 046564, FR-A1-3051 386 and WO-A1-2014/076408.

The use of composite materials is advantageous in the aeronautical industry in particular because these materials have advantageous mechanical performance for relatively low masses.

A process for manufacturing a composite part for the aeronautical industry, which is well known to those skilled in the art, is the RTM molding process, the initials of which refer to the Anglo-Saxon acronym for Resin Transfer Molding.

This is a process for producing a part in composite material based on fibers impregnated with resin. Such a method is for example used to manufacture a bladed part of a turbomachine such as a fan blade or a stator blade.

An RTM process comprises several successive steps.

One begins by carrying out the weaving of fibers to obtain a three-dimensional preform blank, then the blank is cut to obtain a preform having substantially the shape of the bladed part to be obtained. This preform is then placed in a mold, which is closed.

In the current technique, this mold has two functions or two successive uses. The mold is first used to achieve a shaping of the preform by hot compression, it is thus placed in a press and in an oven in order to compress the preform and stiffen it.

The mold is then used to inject resin into the preform for its impregnation. The resin is injected through a supply port of the mold which is then placed in an oven to cause the polymerization of the resin and its hardening.

The bladed part is then removed from the mold and can undergo various successive operations, in particular finishing.

It is advantageous to use a single mold for carrying out the two steps of shaping and resin injection. However, the disadvantage of this technology is that the mold cannot be specifically adapted and optimized for one of these steps since it must also be suitable for carrying out the other step.

This mold is also not suitable for performing other functions such as the co-injection of a metal shield on a leading edge of the bladed part.

The composite material of the bladed part is relatively fragile, and in particular sensitive to shocks, and it is known to protect it by means of a metal shield which is attached and fixed to the leading edge of the bladed part.

The shield can be attached to the blade in several ways. A first way consists in bonding the first shield on the bladed part, after polymerization of the resin.

A second way of fixing a shield on a bladed part consists in fixing the shield by co-molding with the fiber preform. The preform is placed in the mold and the shield is positioned on the edge of the preform intended to form the leading edge of the blade. The injected resin impregnates the preform and comes into contact with the shield to ensure its attachment to the blade after polymerization and hardening. The aforementioned mold of the current technique is not suitable for co-injection and co-molding of the shield. Furthermore, this mold comprises a large number of parts which are movable relative to each other to achieve the shaping by compression. This assembly of the parts creates resin leaks during injection, which leads to waste of resin and requires a complete cleaning of the mold after use.

The present invention proposes a solution to these problems which consists in proposing a molding device specifically adapted to the implementation of only one of the aforementioned functions, namely here the injection of resin into the preform, and which is capable of carrying out concomitantly the attachment of a metal shield to this preform.

Summary of the invention

The invention relates to a device for molding at least one bladed part of a turbomachine, this device comprising at least one internal cavity configured to receive a fiber preform, one edge of which is covered with a metal shield and this device being configured to allow the injection of a resin into the cavity to impregnate said preform and secure the shield to said edge, characterized in that it comprises:

- a base,

- a mold formed of several parts nested inside each other, this mold defining said cavity and being configured to completely enclose said preform, this mold being applied to the base and first sealing means being mounted between the mold and the base,

- a bell mounted on the mold and around the mold, this bell being applied to the base and second sealing means being mounted between the bell and the base, this bell being configured to be held tight against the base and comprising inner surfaces cooperating by wedge effect with complementary outer surfaces of the mold in order to apply a clamping force on the parts of this mold. The wetting device is specifically designed and optimized to carry out the injection of resin into the preform but also the co~injection of the edge of the preform which is covered by the metal shield, that is to say the fixing of this shield on the preform. The different parts of the mold facilitate assembly of the mold around the preform as well as disassembly of the mold after injection and hardening of the resin. The bell covers the mold and is configured to hold the parts of the mold tight together in order to limit, or even prevent, resin leaks between these parts. The base is tightly connected to the mold and to the bell, which prevents resin leakage between these parts, limits the waste of resin, and makes it possible to maintain the pressure at the time of injection, which is important to obtain good quality of the finished part (porosity).

The invention thus makes it possible to optimize the method of molding a bladed part by injecting resin into a preform equipped with a metal shield, in particular by reducing the waste of resin and therefore the manufacturing cost of the bladed part.

The fact of co-injecting the shield and the preform also makes it possible to avoid an additional costly bonding step in the range (autoclave cycle, more difficult pairing with a composite part than with a preform). This also makes it possible to have a better final quality of the bonding because the part is injected "conformed" on the metal shield. It is also possible to carry out the co-moulding with polymerization of an adhesive previously applied to the internal face of the shield to polymerize with the impregnating resin of the preform.

The use of the device for injecting the preform without its prior shaping also makes it possible to considerably reduce the number of parts to form the mould, thus facilitating sealing and allowing savings in resin. The molding device according to the invention may comprise one or more of the following characteristics, taken separately from each other, or in combination with each other:

- the base has a generally parallelepipedic shape and comprises a flat lower surface and an upper surface comprising a central recess for mounting and interlocking a lower end of said mold; the base is for example configured to be extended horizontally in use;

- the base comprises around said recess a first peripheral groove for housing said first sealing means and a second peripheral groove for housing said second sealing means;

- the mold has the general shape of a truncated pyramid and comprises four inclined outer side surfaces connected to the four corners of a flat outer upper surface;

- the bell comprises an internal space for housing the mould, this space comprising four interior lateral surfaces which are inclined in a complementary manner to the exterior surfaces of the mould, and which are also connected to the four corners of a flat interior bottom surface of the bell , the side surfaces and the bottom surface of the space of the bell being intended to rest respectively on the side surfaces and the upper surface of the mould; the sliding of the surfaces of the bell on the surfaces of the mold ensure the clamping of the parts of the mold by wedge effect;

- the mold comprises a lower shell which forms a lower end of the mold and a first side of the mold, this lower shell defining a lower part of the said cavity, and this first side being intended to be located at the level of a leading edge of the bladed part and defining with the lower shell a groove configured to receive said shield; the mold is thus optimized to receive the metal shield and ensure its attachment to the preform via the resin, or even with an additional adhesive; - the mold comprises a side shell which forms a second side of the mold, this second side being opposite the first side and intended to be located at a trailing edge of the bladed part;

- the mold comprises an upper shell which forms an upper end of the mold and which defines an upper part of said cavity;

- the upper shell comprises a first inclined surface intended to cooperate with a first complementary surface of the lower shell, and a second inclined surface intended to cooperate with a second complementary surface of the side shell, said first and second surfaces of the upper shell being located on two opposite sides of the hull and being inclined opposite to the inclination of at least some of said inner surfaces of the bell; the inner surfaces of the bell can be tilted in four different directions; the surfaces of the upper shell can themselves be inclined in two directions opposite to each other and opposite to one of the inner surfaces of the bell; the sliding of the surfaces of the upper shell on the surfaces of the lower shell and of the side shell ensure the clamping of the parts of the mold by wedge effect; - Said first surface extends to the level of said groove.

- said cavity comprises a pay zone and two platform zones, the blade zone extending between the two platform zones;

- the mold further comprises a first end shell intended to be located at one of the platform zones of the cavity, and to define at least part of this zone;

- the mold comprises a second end shell intended to be located at the level of the other of the platform zones of the cavity, and to define at least part of this zone;

- the first and second end shells each comprise at least two parts between which is defined at least part of the corresponding platform zone; - The parts of each of the first and second end shells are mounted on the lower shell, or even on the side shell, and interposed between uprights of the lower shell and of the side shell;

- the lower shell defines a lower part of one of the platform zones of the cavity, and an intermediate piece is attached to the lower shell to define a lower part of the other of the platform zones of the cavity; this makes it possible to authorize or facilitate demoulding;

- the base and/or the bell comprises at least one resin injection port;

- The bell is made in one piece, or in two pieces, namely a belt and a cover;

The present invention also relates to a process for molding at least one bladed turbomachine part by means of a molding device as described above, characterized in that it comprises the steps of: a) mounting a preform in the cavity of the mold as well as a metal shield arranged on one edge of this preform, b) closing the molding device by enclosing the mold between the base and the bell, c) putting the molding device of so as to clamp the mold between the bell and the base, or even also to heat the device, and d) injection of resin into the molding device in order to impregnate the preform and fix the shield to this preform.

The stripping of the bladed part can then take place.

Brief description of figures

Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[Fig.1] Figure 1 is a schematic perspective view of a bladed part of a turbomachine;

[Fig.2] Figure 2 is a schematic perspective view of a molding device according to one embodiment of the invention; [Fig.3] Figure 3 is a schematic sectional view along the line lil-lil of Figure 2, and shows a preform located in the molding device; [Fig.4] Figure 4 is a schematic sectional view along the line IV-IV of Figure 2, and shows the preform located in the molding device;

[Fig.5] Figure 5 is a schematic perspective view of a base of the molding device of Figure 2;

[Fig.6] Figure 8 is a schematic perspective view of a lower shell of the molding device of Figure 2;

[Fig.7] Figure 7 is a schematic perspective view of the lower shell and the base of the molding device of Figure 2;

[Fig.8] Figure 8 is a schematic perspective view of the lower shell and the base of the molding device of Figure 2, and the bladed part disposed on the lower shell;

[Fig.9] Figure 9 is a view similar to that of Figure 8 and also shows schematic positioning members;

[Fig.10] Figure 10 is a schematic perspective view of the lower shell, the base and the side shell of the molding device of Figure 2, as well as the bladed part disposed between the lower and side shells ;

[Fig.11] Figure 11 is a schematic perspective view of the lower shell, the base, the side shell, and first parts of end shells of the molding device of Figure 2, as well as the bladed part arranged between these shells;

[Fig.12] Figure 12 is a schematic perspective view of the lower shell, the base, the side shell, the first parts of end shells, and an upper shell of the molding device of the Figure 2, as well as the bladed part disposed between these shells;

[Fig.13] Figure 13 is a schematic perspective view of the complete mold and the base of the molding device of Figure 2;

[Fig.14] Figure 14 is a larger scale view of a detail of Figure 4; [Fig.15] Figure 15 is a larger scale view of another detail of Figure 4;

[Fig.16] Figure 16 is a view similar to that of Figure 2 and shows an alternative embodiment of the molding device and in particular of its bell; and

[Fig.17] Figure 17 is a view similar to that of Figure 13 and shows another embodiment of the molding device.

Detailed description of the invention

Reference is first made to FIG. 1 which illustrates a bladed part 10 made of composite material for a turbomachine, this bladed part 10 being for example a fan blade or a stator blade, for example of a secondary flow in the case of a turbofan engine. The bladed part 10 comprises a blade 12. In the case represented where the part 10 is a fan blade, this blade 12 is connected by a stilt 14 to a foot 16 which has for example a dovetail shape and is shaped to be engaged in a cell of complementary shape of a rotor disc, in order to retain the blade on this disc.

In the alternative case where part 10 is a stator blade, blade 12 extends between two platforms 16a, 16b which extend substantially parallel to each other and perpendicular to an axis of elongation of blade 12.

The blade 12 comprises a leading edge 12a and a trailing edge 12b of the gases which flow in the turbomachine. The blade 12 has a curved or even twisted aerodynamic profile and comprises a lower surface 18 and a lower surface 20 extending between the leading 12a and trailing 12b edges.

The blade 12 is made from a fiber preform obtained by three-dimensional weaving of fibers, for example carbon.

The leading edge 12a of the blade is reinforced and protected by a metal shield 22 which is fixed to this leading edge 12a. The shield 22 is for example made of an alloy based on nickel and cobalt. In the present invention, this attachment is made by co-molding the preform with the shield 22 by means of a molding device 30, a first embodiment of which is shown in Figures 2 to 15.

The molding device 30 is shown in its entirety in Figure 2. In the example shown, it has a generally parallelepipedic shape.

Figures 3 and 4 represent sectional views of the device 30 and show that it comprises at least one internal cavity 32 configured to receive the fiber preform and the shield 22 of the bladed part 10 to be produced. In the example shown, this bladed part 10 is a stator blade. It can therefore be seen that the cavity 32 essentially comprises three parts or zones, a pay zone Z1 intended to receive the part of the preform forming the blade 12 of the bladed part 10, and two platform zones Z2, Z3 intended to receive the parts of the preform forming the platforms 16a, 16b of the bladed part 10.

The cavity 32 is further configured to receive the metal shield 22 which is previously placed on the edge of the preform intended to form the leading edge 12a of the blade 12.

The molding device 30 is configured to allow the injection of a thermosetting resin into the cavity 32 in order to impregnate the preform and ensure the fixing of the shield 22 on this resin-impregnated preform. Fixing can be ensured either directly by the resin which acts as glue, or by an added film of glue. Figure 4 shows a resin injection port 34 which is located on one side of the device, and this device 30 preferably also includes a port 36 which allows the evacuation of excess resin and also to pull the vacuum and to Avoid trapping air in the cavity (porosity). This port 36 is for example located at an upper end of the device.

The molding device 30 essentially comprises three elements, namely a base 38, a mold 40 and a bell 42. The base 38 forms a support and has a generally parallelepipedal shape in the example shown. The base 38 is represented alone in FIG. 5. The base 38 comprises a flat lower surface 38a which can be applied directly to a flat and horizontal support surface or rest on a platen of a press.

The base 38 further comprises an upper surface 38b comprising a central recess 44 for mounting and interlocking a lower end 40aa of the mold 40. This recess 44 has a generally rectangular or parallelepipedic shape.

The base 38 comprises around the recess 44 a first peripheral groove 48a for housing first sealing means, and a second peripheral groove 48b for housing second sealing means. These sealing means are, for example, elastomer gaskets which each form a closed loop. It can be seen that the groove 46a extends around and close to the recess 44 and that the groove 46b extends between the groove and the outer peripheral edge of the base 38. The bell 42 is particularly visible in FIGS. 4. As its name indicates, this element has a bell shape which can be considered as comprising a peripheral belt 42a and a cover 42b covering this belt.

In the embodiment of Figures 2 to 15, the bell 42 is formed in one piece while in the variant embodiment of Figure 16, the bell 42 is formed in two parts by the assembly of a belt 42a and a cover 42b.

The bell 42 is configured to be mounted on the mold 40 and around the mold 40. It is further configured to bear in a sealed manner on the base 38 and to bear against the mold 40 by exerting on the latter a force of wedge pressure.

In the example shown, the bell 42 externally has the general shape of a parallelepiped whose width and length dimensions are comparable to those of the base 38, so that, when the bell 42 is placed on the base 38, their side faces are substantially aligned in pairs (see Figure 2). The bell 42 has a thickness greater than that of the base 38. The bell 42 has a flat upper surface 42c which can rest on a jaw or another plate of a press.

The sealing between the bell 42 and the base 38 is ensured by the sealing means located in the groove 46b. For this, the lower end of the bell 42 rests on these sealing means which are thus clamped on assembly between the bell 42 and the base 38. The bell 42 comprises an internal space 48 for housing the mold 40. This space 48 opens on a lower surface at the lower end of the bell 42.

Space 48 delimits a volume in the shape of a truncated pyramid. The space 48 thus has four inner side surfaces 48a, 48b, 48c, 48d which are inclined and which are also connected to the four corners of a flat inner bottom surface 48e of the bell 48. The surface 48e is rectangular here. The side surfaces 48a, 48b, 48c, 48d each have a generally trapezoidal shape.

The side surfaces 48a, 48b are located on two opposite sides of the bell 42 and at the level of the platform zones Z2, Z3 of the cavity 32 (cf. FIG. 4). The side surfaces 48c, 48d are located on two opposite sides of the bell 42 and at the level of the leading 12a and trailing 12b edges of the payroll 12 (cf. FIG. 3). Figure 4 shows that the aforementioned injection port 34 opens onto the surface 48a, near the lower end of the bell 42.

The inner surfaces 48a, 48b, 48c, 48d and 48e of the bell 42 are intended to rest on complementary surfaces of the mold 40 in order to apply by wedge effect a clamping and holding force of the mold 40 which is produced by assembling several parts. The mold 40 has the general shape of a truncated pyramid and comprises four outer side surfaces 40a, 40b, 40c, 40d inclined and connected to the four corners of a flat outer top surface 40th. The 40th surface is rectangular here. The side surfaces 40a, 40b, 40c, 40d each have a generally trapezoidal shape.

The side surfaces 40a, 40b are located on two opposite sides of the mold 40 and at the level of the platform zones Z2, Z3 of the cavity 32 (cf. FIG. 4). The side surfaces 40c, 40d are located on two opposite sides of the mold and at the level of the leading 12a and trailing 12b edges of the payroll 12 (cf. FIG. 3).

As can be seen in FIGS. 3 and 4, the sur-faces 48a, 48b of the bell 42 are substantially complementary to the surfaces 40a, 40b and intended to cooperate by sliding and bearing with these surfaces 40a, 40b when the bell 42 is mounted on the mold 40. The surfaces 48c, 48d of the bell 42 are substantially complementary to the surfaces 40c, 40d and intended to cooperate by sliding and bearing with these surfaces 40c, 40d when the bell 42 is mounted on the mold 40. The surface 48e of the bell 42 is intended to bear against the surface 40e when the bell 42 is mounted on the mold 40.

The lower end 40aa of the mold 40 is engaged in the recess 44 of the base 38 and comprises a complementary shape to be engaged by male-female interlocking and in this recess. The lower end 40aa of the mold 40 thus comprises a lower boss 50 (cf. FIGS. 3, 4 and 6) which has a shape complementary to the recess 44. The lower end 40aa of the mold 40 comprises a peripheral surface 52 which is extends around the boss 50 and is intended to rest on the sealing means located in the groove 46a of the base 38.

The mold 40 is obtained by assembling several parts to facilitate its assembly around the preform and the shield 22 and above all to facilitate the demolding of the bladed part 10 after hardening of the resin injected into the mold 40.

The parts of the mold 40 are here formed by shells or shell elements which are nested into each other in order to define the cavity 32. As can be seen in the drawings, the cavity 32 is entirely delimited by the mold 40, which means that the mold 40 is configured to fully enclose the preform and loop it 22.

In the non-limiting example shown, the mold 40 essentially comprises five shells, namely:

- a lower shell 54,

- a side shell 58,

- two end shells 58, 60, and

- an upper shell 82.

The lower shell 54 is visible alone in FIG. 6 and mounted on the base 38 in FIG. 7. This shell 54 forms the lower end 4Gaa of the mold 40, which comprises the boss 50, as well as a first side 57 of the mould, namely the one which comprises the surface 40c located on the side of the leading edge 12a of the blade 12 and therefore of the shield 22.

The lower shell 54 defines a lower part of the cavity 32 as well as a groove 64 of this cavity which is shaped to receive the metal shield 22. This groove 84 is located at the junction of the lower end 40aa and the first side 57 of the mold 40. For this, the lower end 40aa of the mold comprises an upper surface 66 having in section a convex curved shape (cf. FIG. 3) intended to be located on the side of the intrados 18 of the blade 12. The first side 57 of the mold includes an inclined surface 68 which extends upward from one edge of the surface 68. The intersection of the surfaces 68, 88 forms the aforementioned groove 84. Figure 3 shows that the surface 68 is located on the side of the surface 40c of the mold and the surface 48c of the bell 42 and that this surface 68 is inclined in a manner opposite to the inclination of the surfaces 40c, 48c. In the example shown, the surfaces 40c, 48c, on the one hand, and the surface 68, on the other hand, converge towards the upper end of the molding device 30.

Figures 4 and 7 show that the surface 68 is connected at the level of the platform zones Z2, Z3 of the cavity 32 to surfaces end 70 which are substantially parallel to each other and perpendicular to the surface 66,

The lower shell 54 defines at least a lower part of each of the platform zones Z2, Z3 of the cavity 32. One of the surfaces 70 can be formed directly on the shell 54 (on the left side in FIG. 4) and the Another of the surfaces 70 (on the right side in FIG. 3) can be formed by an intermediate part 72 attached to the lower shell 54 in order to facilitate the demolding of the bladed part 10, in particular when it has a complex shape or conformation.

The side shell 56 is visible in Figures 3, 10 and 11 in particular and forms a second side 74 of the mold 40, namely that which comprises the surface 40d located on the side of the trailing edge 12b of the payroll 12.

The side shell 56 is mounted and nested on the lower shell 54 and comprises at its lower end a complementary shape (with steps 76 - cf, Figure 3) of part of the mould.

The side shell 56 includes an inclined surface 78 which extends upward from the steps 76. The intersection of the steps 76 and the surface 78 forms a sharp edge 79 which is configured to be positioned along a edge of surface 66 and at the trailing edge 12b of blade 12. Surface 78 therefore extends upward from surface 66.

Figure 3 shows that the surface 78 is located on the side of the surface 40d of the mold and the surface 48d of the bell 42 and that this surface 78 is inclined in a manner opposite to the inclination of the surfaces 40d, 48d, In the example shown, the surfaces 40d, 48d, on the one hand, and the surface 78, on the other hand, converge towards the upper end of the molding device 30. FIG. 3 also shows that the surfaces 68 and 78 have reverse tilts.

Upper shell 62 forms the upper end of mold 40, which includes surface 40e. The shell 62 defines an upper part of the cavity 32. For this, the lower end of the shell 62 comprises a lower surface 80 having in section a concave curved shape (cf. figure 3) intended to be located on the side of the extrados 20 of the blade 12, and to extend from the trailing edge 12b of the payroll 12 to the leading edge 12a and to the metal shield. This surface 80 extends between two inclined lateral surfaces 82, 84 which are complementary to the surfaces 88, 78 and intended to cooperate by sliding and bearing with these surfaces during the assembly of the mold 40. In the assembled position, the upper shell 82 rests on the upper ends of the lower shell 54 and of the side shell 56 (FIG. 3).

Surfaces 82, 84 of upper shell 62 are located at the sides of mold 40 having surfaces 40c and 40d. At the level of the two other sides of the mold comprising the surfaces 40a and 40b, the upper shell comprises end surfaces 86 substantially parallel to one another and perpendicular to the upper surface 40e of the mold. As seen in Figure 4, surfaces 86 are aligned with surfaces 70 when mold 40 is assembled.

The end shells 58, 60 are intended to delimit the platform zones Z2, Z3 of the cavity 32 with a part of the lower shell 54 and of the spacer 72 (FIG. 4).

A first end shell 58 located on the left in FIG. 4 comprises surface 40a and is formed by assembling two parts 58a, 58b delimiting part of platform zone Z2 between them.

A first of the parts 58a is mounted between the upper shell 62 and part of the platform 18a. This first part 58a comprises a surface 58a1 complementary to the surface 86 and intended to cooperate by sliding with the latter during assembly of the mold. This first part 58a further comprises a surface S8a2 delimiting part of the platform zone Z1 (cf. FIG. 14).

The second part 58b is mounted between the part 58a and the bell 42 and comprises the aforementioned surface 40a. The second part 58b further comprises a surface 58b1 delimiting one side of the platform zone Z1, opposite to the blade 12. FIG. 14 shows that the platform zone Z1 is delimited by the surface 58b1, on one side, and by the surfaces 70 and 58a2 on the other side.

The parts 58a, 58b are nested one inside the other thanks to complementary shapes and are also interposed between the first side 57 of the lower shell 54 and the side shell 56. More exactly, as can be seen in Figures 11 at 13, parts 58a, 58b are engaged between uprights 88, 90 of the lower hull 54 and of the side hull 56. Parts 58a, 58b can be mounted by sliding between these uprights by rail-slide systems 92.

The second end shell 60 located on the right in FIG. 4 comprises the surface 40b and is formed by the assembly of two parts 60a, 60b delimiting between them a part of the platform zone Z3,

A first of the parts 60a is mounted between the upper shell 62 and part of the platform 16b. This first part 60a comprises a surface 60a 1 complementary to the surface 86 and intended to cooperate by sliding with the latter during assembly of the mold. This first part 60a further comprises a surface 60a2 delimiting part of the platform zone Z3.

The second part 60b is mounted between the part 60a and the bell 42 and comprises the aforementioned surface 40b. The second part 60b further comprises a surface 60b1 delimiting one side of the platform zone, opposite to the blade 12. FIG. 15 shows that the platform zone Z3 is delimited by the surface 6ûb1, on one side, and by the surface 60a2 and by the surface 70 of the spacer 72, on the other side.

The parts 60a, 60b are nested one inside the other thanks to complementary shapes and are also interposed between the first side 57 of the lower shell 54 and the side shell 56. More exactly, as can be seen in FIGS. at 13, parts 60a, 60b are engaged between uprights 88, 90 of the lower shell 54 and of the side hull 56. Parts 60a, 60b can also be mounted by sliding between these uprights by rail-slide systems 92. Figure 16 shows an alternative embodiment of the bell 42 already mentioned in the foregoing and which consists in making it in two parts, a belt 42a which includes the inner surfaces 48a, 48b, 48c and 48d and a cover 42b which includes the 48th bottom surface. The line of demarcation between the lid 42a and the belt 42b could advantageously be located so as to encapsulate the upper shell 62, in order to keep it integral with the lower shell 54 of the mold and that it does not remain blocked in the bell 42 during unmoulding.

FIG. 17 illustrates another embodiment variant, this time of the mold 40, the lower shell 54 of which may also comprise an additional side (in addition to side 57). In other words, one of the end shells 58, 60 of the mould, or even just a part such as part 60b or part 58b, could be integrated into the lower shell 54.

In yet another variant not shown, the cavity 32 could be shaped to accommodate several preforms for the simultaneous production of several bladed parts, or even several separate cavities for the production of these bladed parts.

The present invention also relates to a method of molding at least one bladed part of a turbomachine by means of the molding device 30.

This method comprises in particular the steps of: a) mounting the preform in the cavity 32 of the mold 40 as well as the metal shield 22 arranged on one edge of this preform, b) closing the molding device 30 by enclosing the mold 40 between the base 38 and the bell 40, c) pressing the molding device 30 so as to clamp the mold 40 between the bell 42 and the base 38, and d) injecting resin into the molding device 30 in order to impregnate the preform and fix the shield 22 to this preform.

Step a) is illustrated in Figures 8 to 13. In FIG. 8, the preform is placed on the lower shell 54 of the mold 40 so that its lower surface 18 rests on the surface 88 and its edge equipped with the metal shield 22 is located in the groove 64. Parts of the platforms 16a, 16b then rest on the surfaces 70. In FIG. 9, positioning members 91 are arranged on the base 38 at the level of the platforms 16a, 16b so as to hold blocks or layers 94 or of woven preform in place, which are added to the surfaces of the platforms opposite the payroll 12. These blocks or layers 94 are particularly visible in FIGS. 14 and 15. These blocks or layers can consist of layers of fibers woven by three-dimensional interlocking like the rest of the preform . In FIG. 14, the block or the layer 94 is arranged between sacrificial (machined) or non-sacrificial glass plies, located on the left in the drawing, for resistance to galvanic corrosion or friction, for example, and woven carbon 3D which makes up the blade of the preform, with continuity of the fibers in the radius, located on the right of the drawing.

In FIG. 10, the side shell 56 is mounted on the lower shell 54 and makes it possible to wedge the trailing edge 12b of the preform.

The parts 58a, 60a of the end shells 58, 60 are mounted between the uprights 88, 90 in Figure 11, then the upper shell 62 is mounted between these parts 58a, 58b and on the preform in Figure 12. Its surface lower 80 then rests on the extrados 20 of the pay 12.

Parts 58b, 60b of end shells 58, 60 58, 60 are then mounted between uprights 88, 90 in Figure 13.

Step b) is illustrated in FIG. 2 and consists in covering the mold 40 with the bell 42 which rests on the mold 40 and on the base 38. Closing the device by the bell 42 makes it possible to position the parts of the mold relative to each other, to press them against each other, and to guarantee compaction of the preform to a predetermined thickness.

The device 30 is placed under a press in step d) in order to clamp the shells 54, 56, 58, 60, 62 of the mold 40 against each other, and the resin is injected into the cavity 32 in step d) . Resin injection can be done by prior heating of the device 30 to a predetermined temperature in order to fluidize the resin. Once the resin has been completely injected, it is heated again to reach a baking temperature and activate the polymerization of the resin and its hardening.

The device according to the invention is advantageous insofar as it is adapted and optimized for the injection of resin into the preform and the simultaneous co-molding of the shield. Furthermore, the dissociation of the mold vis-à-vis the base and the bell allows the use of several mold configurations for the same bell and the same base, the different mold configurations differ from one another. by the shape and dimensions of the internal cavities 32 for example. A device according to the invention can thus be used for the manufacture of several different bladed parts using molds adapted to these parts.

Claims

1. Device (30) for molding at least one bladed part (10) of a turbomachine, this device comprising at least one internal cavity (32) configured to receive a fiber preform, one edge of which is covered with a metal shield (22 ) and this device being configured to allow the injection of a resin into the cavity to impregnate said preform and ensure the fixing of the shield on said edge, characterized in that it comprises:

- a base (38),

- a mold (40) formed of several parts nested inside each other, this mold defining said cavity (32) and being configured to completely enclose said preform, this mold being applied to the base (38) and first means of sealing being mounted between the mold (40) and the base (38),

- a bell (42) mounted on the mold (40) and around the mold (40), this bell (42) being applied to the base (38) and second sealing means being mounted between the bell (42) and the base (38), this bell (42) being configured to be held tight against the base (38) and comprising interior surfaces (48a, 48b, 48c, 48d) cooperating by wedge effect with exterior surfaces (40a , 40b, 40c, 40d) complementary to the mold (40) in order to apply a clamping force to the parts of this mold.

2. Molding device (30) according to claim 1, wherein the base (38) has a generally parallelepipedic shape and comprises a flat lower surface (38a) and an upper surface (38b) comprising a central recess (44) for mounting and fitting a lower end of said mold (40).

3. Molding device (30) according to claim 2, wherein the base (38) comprises around said recess (44) a first peripheral groove (48a) for housing said first sealing means and a second peripheral groove (48b) housing said second sealing means.

4. Molding device (30) according to one of the preceding claims, in which: - the mold (40) has the general shape of a truncated pyramid and comprises four outer lateral surfaces (40a, 40b, 40c, 40d) inclined and connected at the four corners of a flat outer upper surface (40e), and

- the bell (42) comprises an internal space (48) for housing the mold (40), this space (48) comprising four interior lateral surfaces (48a, 48b, 48c, 48d) which are inclined in a complementary manner to the exterior surfaces ( 40a, 40b, 40c, 40d) of the mold (40), and which are also connected to the four corners of a flat inner bottom surface (48e) of the bell, the side surfaces (48a, 48b, 48c, 48d) and the bottom surface (48e) of the space of the bell (42) being intended to bear respectively on the side surfaces (40a, 40b, 40c, 40d) and the upper surface (40e) of the mold (40).

5. Molding device (30) according to one of the preceding claims, wherein the mold comprises at least:

- a lower shell (54) which forms a lower end of the mold (40) and a first side (57) of the mold, this lower shell (54) defining a lower part of the said cavity (32), and this first side (57 ) being intended to be located at a leading edge (12a) of the bladed part (10) and defining with the lower shell a groove (64) configured to receive said shield (22), - a side shell ( 58) which forms a second side (74) of the mold (40), this second side being opposite the first side (57) and intended to be located at the level of a trailing edge (12b) of the bladed part (10) , and

- an upper shell (82) which forms an upper end of the mold (40) and which defines an upper part of said cavity (32).

6. Molding device (30) according to the preceding claim, wherein the upper shell (62) comprises a first inclined surface (82) intended to cooperate with a first surface (68) complementary to the lower shell (54), and a second inclined surface (84) intended to cooperate with a second surface (78) complementary to the side shell (56), said first and second surfaces (82, 84) of the upper shell (62) being located on two opposite sides of the shell (42) and being sloped opposite to the slope of at least some of said interior surfaces (48c, 48d) of the cioche (42).

7. Molding device (30) according to the preceding claim, wherein said first surface (82) extends to the level of said groove (64).

8. Molding device (30) according to the preceding claim, in which, said cavity (32) comprising a blade zone (Z1) and two platform zones (Z2, Z3), the pay zone extending between the two platform areas, the mold (40) further comprises:

- a first end shell (58) intended to be located at one of the platform zones (Z2) of the cavity (32), and to define at least part of this zone, and

- a second end shell (60) intended to be located at the level of the other of the platform zones (Z3) of the cavity (32), and to define at least part of this zone.

9. Molding device (30) according to the preceding claim, wherein the first and second end shells (58, 60) each comprise at least two parts (58a, 58b, 60a, 60b) between which is defined at least one part of the corresponding platform zone (Z2, Z3).

10. Molding device (30) according to the preceding claim, in which the parts of each of the first and second end shells (58, 60) are mounted on the lower shell (54), or even on the side shell (56), and interposed between uprights (88, 90) of the lower hull (54) and the side hull (56).

11. Molding device (30) according to one of claims 7 to 9, in which the lower shell (54) defines a lower part of one of the platform zones (Z2, Z3) of the cavity (32), and a spacer (72) is attached to the lower shell (54) to define a lower part of the other of the platform zones (Z2, Z3) of the cavity (32).

12. Molding device (30) according to one of the preceding claims, wherein the base (38) and / or the bell (42) comprises at least one port (34) for injecting resin.

13. Molding device (30) according to one of the preceding claims, wherein the bell (42) is made in one piece, or in two parts, namely a belt (42a) and a cover (42b).

14. Process for molding at least one bladed part (10) of a turbomachine by means of a molding device (30) according to one of the preceding claims, characterized in that it comprises the steps of: a) mounting a preform in the cavity (32) of the mold (40) as well as a metal shield (22) arranged on one edge of this preform, b) closing the molding device (30) by enclosing the mold (40) between the base (38) and the bell (42), c) pressing the molding device (30) so as to clamp the mold (40) between the bell (42) and the base (38), or even also heating the device, and d) injecting resin into the molding device (30) in order to impregnate the preform and fix the shield (22) to this preform.