Device for handling a membrane and manufacturing method implementing the device

Abstract

The invention relates to a device (280) for handling an annular membrane, in particular for manufacturing an annular casing of an aircraft turbine engine, characterised in that the device (280) comprises: - an annular bell-shaped cover (290) that extends around a main axis (Y) and is configured to be mounted around the membrane, wherein the bell-shaped cover (290) comprises a first longitudinal end (320a) capable of being attached to a first longitudinal end of the membrane, a second longitudinal end (320b), which is opposite the first longitudinal end (320a) and is capable of being attached to a second, opposite longitudinal end of the membrane; and - a system (300) for evacuating an annular space located between the bell-shaped cover (290) and the membrane in order to radially expand the membrane outward.

Description

[0001] DESCRIPTION

[0002] TITLE: DEVICE FOR HANDLING A MEMBRANE AND MANUFACTURING METHOD USING THE DEVICE

[0003] Technical field of the invention

[0004] The invention relates to the field of membrane handling devices, in particular used for the manufacture of annular casings for aircraft turbomachines.

[0005] The invention relates in particular to the field of manufacturing annular casings for aircraft turbomachines, such as fan casings.

[0006] Technical background

[0007] An aircraft turbomachine generally extends along and around a longitudinal axis. It comprises a gas generator which typically comprises, from upstream to downstream, in the direction of gas flow in the turbomachine, a low-pressure compressor, a high-pressure compressor, a gas combustion chamber, a high-pressure turbine and a low-pressure turbine.

[0008] The low-pressure compressor rotor is typically connected to the low-pressure turbine rotor via a low-pressure shaft. The high-pressure compressor rotor is connected to the high-pressure turbine rotor via a high-pressure shaft.

[0009] The turbomachine further comprises a fan which is located upstream of the gas generator. The fan comprises a rotor comprising a disc centered on the longitudinal axis and which is rotated about the longitudinal axis by a fan shaft. The fan further comprises blades extending radially from the disc. The turbomachine further comprises annular casings generally arranged around the rotating elements of the turbomachine ensuring the retention, for example, of the rotor blades. Among these casings, the fan casing is known, for example, which is annular and centered on the longitudinal axis of the turbomachine. The fan casing is typically arranged around the rotor of the fan and has the main function of retaining the fan blades.

[0010] In order to reduce the overall mass of the turbomachine, it has been proposed to make the turbomachine casings, in particular the fan casing, from a composite material. The composite material typically comprises a polymer matrix and fibers embedded in the polymer matrix. The fibers are organized in the form of an annular fiber preform.

[0011] They are chosen, for example, from carbon, aramid or glass fibers.

[0012] Such a composite fan casing is typically produced by resin transfer molding, also known by the acronym RTM for "Resin Transfer Molding". In the context of the manufacture, for example, of a composite fan casing, a step of arranging an annular fiber preform in a mold is carried out and then a polymer resin is injected into the mold. A resin polymerization step is then carried out to form the polymer matrix of the composite material of the fan casing.

[0013] The mold typically comprises an annular mandrel and an annular outer wall arranged coaxially around the mandrel. The mandrel and the outer wall of the mold define between them an annular injection cavity in which the fiber preform is arranged. The mold further comprises a port for injecting the resin into the injection cavity.

[0014] The mandrel conditions or defines the internal profile of the fan casing while the external wall conditions or defines the external profile of the casing. Although particularly efficient, it has been found that the resin injection time in such a manufacturing process is particularly long due to a lack of pressure between the external wall and the fiber preform. In addition, it has been found that the pressure applied to the fiber preform is non-uniform leading to manufacturing defects.

[0015] To overcome these few drawbacks, it has been proposed to arrange an annular membrane radially between the external wall and the fiber preform. The membrane thus delimits with the mandrel the resin injection cavity and externally delimits a compaction cavity into which a compaction fluid such as oil can be injected. This makes it possible to optimize and standardize the compression forces of the fiber preform during resin injection. The fan casing has better mechanical properties thanks to such a process. However, the implementation of such a manufacturing process presents challenges. Indeed, although the membrane is elastically deformable, its handling and installation around the fiber preform is complex and laborious.

[0016] Before resin injection, the fiber preform has an external diameter greater than the internal diameter of the membrane due to the absence of resin constraining the fibers. In addition, the membrane is often made of silicone and thus has a high coefficient of thermal expansion. It is thus conformable when hot but at room temperature, its diameter is smaller than the diameter of the fiber preform. Thus, it is difficult to install the membrane around the fiber preform. Its installation often requires the mobilization of several operators who must apply significant tensile forces on the membrane to place it around the fiber preform. These tensile forces can even in some cases prove insufficient or lead to rupture of the membrane.

[0017] Therefore, there is a need to provide a solution for the installation or handling of a membrane, in particular for the manufacture of an annular casing of an aircraft turbomachine. Summary of the invention

[0018] For this purpose, the invention proposes an assembly comprising

[0019] - an annular membrane, in particular for the manufacture of an annular casing for an aircraft turbomachine, and

[0020] - a device for handling the annular membrane.

[0021] The device of the assembly according to the invention is remarkable in that the device comprises:

[0022] - an annular bell extending around a main axis and mounted around the membrane, the bell having a first longitudinal end attached to a first longitudinal end of the membrane, a second longitudinal end, opposite the first longitudinal end, and attached to a second opposite longitudinal end of the membrane, and

[0023] - a system for creating a vacuum in an annular space located between the bell and the membrane in order to expand the membrane radially outwards.

[0024] The device of the invention thus comprises a bell which can be mounted coaxially around the membrane and a system for creating a vacuum in the annular space formed radially between the membrane and the bell.

[0025] The evacuation of this annular space allows the membrane to expand radially outwards. Thus, the annular membrane has, after the evacuation of this annular space, an internal diameter greater than the internal diameter of the membrane before this evacuation.

[0026] Thanks to such expansion, the membrane has an internal diameter large enough to be easily installed around the fiber preform for the manufacture of the casing by injection molding.

[0027] Thanks to the device of the invention, the handling of the membrane is facilitated and it is therefore no longer necessary to implement significant efforts during its installation around the fiber preform. The invention may comprise one or more of the following characteristics, taken in isolation from each other or in combination with each other:

[0028] -- the membrane is elastically deformable;

[0029] - the bell comprises a first annular flange at its first longitudinal end, capable of being fixed to a corresponding first annular flange of the first longitudinal end of the membrane, and a second annular flange at its second longitudinal end, capable of being fixed to a corresponding second annular flange of the second longitudinal end of the membrane,

[0030] - the first and second annular flanges of the bell carry sealing elements capable of cooperating with the first and second annular flanges of the membrane,

[0031] - the bell comprises an annular body centered on the main axis and axial reinforcing ribs regularly distributed around the main axis,

[0032] - the vacuum system comprises at least one conduit in fluid communication with the annular space,

[0033] - the duct extends along the annular body and is connected to one of the ribs,

[0034] - the membrane forms a bladder and comprises first and second coaxial annular skins, respectively internal and external, which are connected together in a sealed manner respectively to the first and second longitudinal ends of the membrane,

[0035] - the membrane comprises a material comprising a silicone and possibly reinforcing fibers,

[0036] - a positioning device located inside the bell and around the membrane,

[0037] - two positioning members, each positioning member being located inside the bell and around the membrane.

[0038] The invention also relates to a method for manufacturing an annular casing of an aircraft turbomachine, the casing comprising a composite material comprising a polymer matrix and an annular fibrous preform embedded in the matrix.

[0039] The method according to the invention is remarkable in that it comprises the following steps:

[0040] (a) provide an assembly according to any of the preceding characteristics,

[0041] (b) create a vacuum in the annular space,

[0042] (c) provide an annular mandrel,

[0043] (d) arranging the fiber preform coaxially around the mandrel, and

[0044] (e) arranging the assembly around the fiber preform, the mandrel and the membrane defining a cavity for injecting a resin in which the fiber preform is located.

[0045] The method may comprise one or more of the following features, taken in isolation from each other or in combination with each other:

[0046] (f) injecting a compaction fluid into a compaction cavity located around the injection cavity, and

[0047] (g) inject the resin into the injection cavity.

[0048] The invention also relates to an annular membrane for the manufacture of an annular casing of an aircraft turbomachine, the membrane having a main axis and extending longitudinally between first and second annular longitudinal ends and comprising:

[0049] - a first annular skin centered on the main axis.

[0050] The membrane is remarkable in that it forms a bladder and further comprises:

[0051] - a second annular skin arranged coaxially around the first skin, the first and second skins delimiting between them a sealed annular compaction cavity intended to receive a compaction fluid, and - a port for injecting the compaction fluid opening into the compaction cavity.

[0052] The membrane is double-skinned, forming a bladder for filling the compaction fluid. The compaction fluid, such as oil, is therefore confined between the first and second skins of the membrane, which ensure the mold remains watertight during filling and emptying of the bladder.

[0053] The risks of contamination of operators by the compaction fluid are thus limited, reinforcing the safety and health of operators compared to a single-skin membrane.

[0054] Also, the risks of contamination of the fiber preform are limited, reducing the risk of discarding the casing.

[0055] The membrane may comprise one or more of the following features, taken in isolation from each other or in combination with each other:

[0056] - the first and second skins each comprise, opposite the first longitudinal end, a collar extending radially,

[0057] - a first annular flange at the first longitudinal end and a second annular flange at the second longitudinal end of the membrane, the first and second flanges sealingly connecting the first and second skins together at the first and second longitudinal ends of the membrane,

[0058] - the second flange is inserted between the first and second skins at the second longitudinal end,

[0059] - the second flange is inserted between the collars of the first and second skins,

[0060] - the first flange rests on an annular spacer centered on the main axis, - an annular insert centered on the main axis and located at the first longitudinal end of the membrane, the insert being inserted between the first and second skins,

[0061] - the insert comprises a radial free end arranged between the reinforcement and the first flange and an axial free end interposed between the first and second skins,

[0062] - a material comprising a silicone and possibly reinforcing fibers.

[0063] The invention also relates to a mold for manufacturing an annular casing of an aircraft turbomachine, the mold comprising:

[0064] - an annular mandrel,

[0065] - a membrane arranged coaxially around the mandrel, the mandrel and the membrane defining an injection cavity, the membrane comprising any one of the preceding characteristics.

[0066] The invention also relates to a method for manufacturing an annular casing of an aircraft turbomachine, the casing comprising a composite material comprising a polymer matrix and an annular fibrous preform embedded in the matrix.

[0067] The process is remarkable in that it includes the following steps:

[0068] (a) provide an annular mandrel,

[0069] (b) arranging the fiber preform coaxially around the mandrel,

[0070] (c) arranging a membrane according to any of the preceding characteristics around the fibrous preform,

[0071] (d) injecting a resin into an injection cavity defined between the mandrel and the membrane and a compaction fluid into the compaction cavity.

[0072] Brief description of the figures Other characteristics and advantages will emerge from the following description of non-limiting embodiments of the invention with reference to the appended drawings in which:

[0073] [Fig.1] Figure 1 is a perspective view of an example of an aircraft turbomachine according to the invention;

[0074] [Fig.2] Figure 2 is a perspective view of a fan casing fitted to the turbomachine of Figure 1;

[0075] [Fig. 3] Figure 3 is a simplified schematic sectional view of a mold for manufacturing the fan casing of Figure 2 comprising a membrane according to a first embodiment;

[0076] [Fig. 4] Figure 4 is a simplified schematic sectional view of a mold for manufacturing the fan casing of Figure 2 comprising a membrane according to a second embodiment;

[0077] [Fig.5] Figure 5 is a perspective view of the membrane according to the second embodiment;

[0078] [Fig.6] Figure 6 is a longitudinal sectional view of a half membrane according to the invention;

[0079] [Fig.6a] Figure 6a is a view of a part of the membrane according to the second embodiment;

[0080] [Fig.7] Figure 7 is a perspective view of the membrane handling device according to the invention;

[0081] [Fig.8] Figure 8 is a perspective view of an assembly comprising the handling device according to the invention and the membrane around which the device is mounted;

[0082] [Fig.9] Figure 9 is a longitudinal sectional view of the half-assembly of Figure 8;

[0083] [Fig.10] Figure 10 is a perspective view of a membrane being installed around a fiber preform using the handling device according to the invention;

[0084] [Fig.11] Figure 11 is a block diagram of a manufacturing method according to the invention, [Fig.12] Figure 12 is a longitudinal sectional view of a half-assembly according to another embodiment of the invention.

[0085] Detailed description of the invention

[0086] An example of an aircraft turbomachine 1 according to the invention is shown in FIG. 1. The turbomachine 1 is for example a double-flow turbojet.

[0087] The turbomachine 1 extends along a longitudinal axis X. A gas flow F flows into the turbomachine 1.

[0088] For the purposes of the present invention, the terms "upstream" and "downstream" are understood to mean relative to the direction of flow of the gas flow F in the turbomachine 1 along the longitudinal axis X.

[0089] The turbomachine 1 comprises, from upstream to downstream, a fan 2 and a gas generator. The gas generator comprises, from upstream to downstream, a low-pressure compressor 3, a high-pressure compressor 4, at least one combustion chamber 5, a high-pressure turbine 6 and a low-pressure turbine 7. The fan 2 is typically mounted upstream of the low-pressure compressor 3.

[0090] Each compressor 3, 4 comprises a compressor rotor and each turbine 6, 7 comprises a turbine rotor. The compressor and turbine rotors are composed of a plurality of stages each comprising a bladed wheel.

[0091] The compressor rotor of the low-pressure compressor 3 is connected to the turbine rotor of the low-pressure turbine 7 by a low-pressure shaft (not shown). They form a low-pressure body.

[0092] The compressor rotor of the high-pressure compressor 4 is connected to the turbine rotor of the high-pressure turbine 6 by a high-pressure shaft (not shown). They form a high-pressure body.

[0093] The low-pressure and high-pressure shafts are centered on the longitudinal axis X and rotatable about the longitudinal axis X. The high-pressure shaft is arranged coaxially around the low-pressure shaft. The gas flow F passes through the fan 2 and is divided into a primary air flow passing through a primary vein and a secondary air flow passing through a secondary vein surrounding the primary vein. The primary air flow passes through the low-pressure 3 and high-pressure 4 compressors. The compressed primary air flow then passes through the combustion chamber 5 in which it is mixed with a fuel. The gases resulting from the combustion thus pass through the high-pressure 6 and low-pressure 7 turbines. The energy of the gases is transformed by the turbine rotor of the low-pressure turbine 7 into mechanical energy making it possible to rotate the low-pressure shaft and consequently the low-pressure compressor.

[0094] The fan 2 comprises a disk 2a centered on the longitudinal axis X and rotatable about the longitudinal axis X. The disk 2a is driven in rotation by a fan shaft. Advantageously, the fan shaft is connected to the low-pressure shaft via a mechanical speed reducer (not shown). The speed reducer allows the fan shaft to be driven at a rotational speed lower than the rotational speed of the low-pressure shaft. This makes it possible to increase the bypass ratio of the turbomachine 1. The fan 2 further comprises blades 2b regularly distributed about the longitudinal axis X and extending radially from the disk 2a relative to the longitudinal axis X.

[0095] The turbomachine 1 further comprises at least one casing 8, 9. In the present description, a casing is a fixed structure of the turbomachine 1. According to the invention, the casing 8, 9 comprises a composite material. The composite material comprises a matrix and fibers embedded in the matrix. The matrix is ​​polymeric and is chosen from thermoplastic or thermosetting polymers. The thermoplastic polymer is for example a polyamide, a polyethylene, a polypropylene, a polyvinylidene fluoride or a mixture thereof. The thermosetting polymer is for example an epoxy. The fibers are for example carbon, glass or aramid fibers or a mixture thereof. The fibers are organized in the form of a fiber preform 100. The fiber preform 100 is for example woven.

[0096] The casing 8, 9 may be a fan casing 8 arranged around the blades 2b. The casing 8, 9 may also be an intermediate casing 9 located downstream of the fan casing 8 and surrounding the low-pressure compressor 3.

[0097] As best seen in Figure 2, the fan casing 8 is centered on the longitudinal axis X. It comprises an annular body 10, an upstream annular flange 11 and a downstream annular flange 12 which are located at the axial ends of the annular body 10. The downstream annular flange 12 is for example connected by bolting to the intermediate casing 9.

[0098] The fan casing 8 has an outer profile 13 and an inner profile 14. The outer profile 13 may vary from one fan casing to another depending on the specifications of the fan casing 8. For example, the distance separating the outer profile 13 from the inner profile 14 may vary between the fan casings 8.

[0099] The casings 8, 9 made of composite material of the turbomachine 1, in particular the fan casing 8, are manufactured by resin transfer molding, also known by the English acronym RTM for “Resin Transfer Molding”.

[0100] Each casing 8, 9 is thus manufactured within a mold 15 illustrated briefly and schematically in figures 3 and 4 aimed at illustrating the principle of the mold 15.

[0101] The mold 15 is described for the manufacture of the fan casing 8 for example but can be used for the manufacture of the intermediate casing 9 or any casing of the turbomachine 1.

[0102] In the remainder of the description, the terms “longitudinal”, “longitudinally”, “radial”, “radially” are understood relative to a main axis Y of the mold 15. The terms “exterior”, “interior” are understood relative to the distance from the main axis Y along a radial axis perpendicular to the main axis Y. The mold 15 comprises a mandrel 16 and optionally an external wall 17.

[0103] The mandrel 16 is annular and extends around and along the main axis Y. The mandrel 16 comprises a body 16a for depositing the fiber preform 100 of the fan casing 8. The body 16a has, for example, an external surface around which the fiber preform 100 is wound. The fiber preform 100 may be formed from several sheets of fibers which are draped over the mandrel 16. The mandrel 16 further comprises first and second radial walls 16b, 16c located at the axial ends of the body 16a. The first and second radial walls are annular and connected to the body 16a of the mandrel 16. They each have an annular external peripheral edge having, for example, fixing orifices.

[0104] The mandrel 16 is for example metallic. It is advantageously formed from a single piece.

[0105] The outer wall 17 is annular and centered on the main axis Y. It is arranged coaxially around the mandrel 16. The outer wall 17 is for example metallic. It is fixed to the first and second radial walls 16b, 16c. It comprises for example lateral flanges fixed on the outer peripheral edge 16c of the radial walls 16a, 16b of the mandrel 16 by bolting for example. The lateral flanges are fixed radially on the outer peripheral edges.

[0106] According to a particularly preferred embodiment of the invention, the external wall 17 of the mold 15 is sectorized. It comprises a plurality of angular sectors 18 regularly distributed around the main axis Y. Each angular sector 18 extends around the main axis Y over an angular range of between 30° and 120°, preferably between 30° and 90°, even more preferably between 45° and 60°. Advantageously, the external wall 17 comprises between three and twelve angular sectors 18, preferably between four and twelve angular sectors 18, even more preferably between six and eight angular sectors 18. The number of sectors will of course depend on the dimensions of the mold 15 and consequently on those of the casing to be obtained.

[0107] The mold 15 further comprises an annular membrane 19 centered on the main axis Y. The membrane 19 thus extends around and along the main axis Y. The membrane 19 delimits with the mandrel 16 an injection cavity C1 for the resin.

[0108] The membrane 19 is elastically deformable. It advantageously comprises a polymer material, preferably chosen from silicones. The material of the membrane 19 may further comprise reinforcing fibers embedded in the polymer. The reinforcing fibers are, for example, made of polyester.

[0109] The membrane 19 extends between first and second longitudinal ends 20a, 20b.

[0110] The membrane 19 is advantageously non-sectorized. It is thus advantageously formed in one piece. The membrane 19 advantageously has a thickness e of between 4 mm and 10 mm, preferably 8 mm.

[0111] According to an embodiment illustrated in Figure 3, the membrane 19 is single-skinned. The membrane 19 may comprise annular channels (not shown). The annular channels open into an oil recovery zone. This makes it possible to improve the emptying of the mold 15 and the recovery of the oil for recycling.

[0112] According to a particularly advantageous embodiment illustrated in Figures 4 to 6, the membrane 19 forms at least one bladder and comprises at least first and second annular skins 21, 22 centered on the main axis Y. The membrane 19 can comprise several bladders, and therefore more than two coaxial skins centered on the main axis Y.

[0113] The second skin 22 is arranged coaxially around the first skin 21. The second skin 22 is thus the outer skin and the first skin 21 represents the inner skin. The first and second skins 21, 22 extend longitudinally between the first and second longitudinal ends 20a, 20b. The first and second skins 21, 22 define between them a sealed annular compaction cavity C2.

[0114] The first and second skins 21, 22 each have a thickness for example between 2 mm and 5 mm, preferably 4 mm.

[0115] With reference to Figures 5 and 6, the first and second skins 21, 22 respectively have first and second collars 23, 24 located at the second longitudinal end 20b of the membrane 19. The first and second collars 23, 24 extend radially. The first and second skins 21, 22 thus have a first external diameter D1 at the first end 20a which is less than a second external diameter D2 at the second end 20b. Preferably, the second external diameter D2 is twice the first external diameter D1.

[0116] The second collar 24 of the second skin 22 has a first face 25 oriented towards the first longitudinal end 20a of the membrane 19 and a second face 26 axially opposite and therefore oriented towards the second longitudinal end 20b of the membrane 20. The first face 25 comprises a first radial annular surface 25a which is located in a first plane perpendicular to the main axis Y. The first face 25 further comprises a frustoconical annular surface 25b which widens from the first radial annular surface 25a towards the first longitudinal end 20a. The first face 25 further comprises a second radial annular surface 25c parallel to the first radial annular surface 25a and which is connected to the frustoconical annular surface 25b. The second face 26 comprises surfaces complementary to or parallel to the surfaces of the first face 25.It thus comprises a first radial annular surface 26a which is located in a second plane perpendicular to the main axis Y and parallel to the first plane. The second face 26 further comprises a frustoconical annular surface 26b which flares out from the first radial annular surface 26a and towards the first longitudinal end 20a. The second face 26 further comprises a second radial annular surface 26c parallel to the first radial annular surface 26a and which is connected to the frustoconical annular surface 26b.

[0117] The first collar 23 of the first skin 21 has a first face oriented towards the second collar 24 and a second axially opposite face. The first face has a radial annular surface 27 parallel to the first radial annular surface 25a of the second collar 24.

[0118] At the first longitudinal end 20a of the membrane 19 axially opposite the collars 23, 24, the second skin 22 has first and second axially superimposed shoulders 28a, 28b. The second skin 22 further comprises an annular surface 29 connected to the second shoulder 28b by a frustoconical surface 28c which widens towards the second longitudinal end 20b. The annular surface 29 is also parallel to the first radial annular surface 25a of the second collar 24.

[0119] At the first longitudinal end 20a of the membrane 19, the first skin 21 has a free annular surface 30. This free annular surface 30 is parallel to the annular surface 29 of the second skin 22.

[0120] The membrane 19 further comprises first and second annular flanges 31, 32 located respectively at the first and second longitudinal ends 20a, 20b of the membrane 19. The first and second flanges 31, 32 are annular and centered on the main axis Y. The first and second flanges 31, 32 each have an annular body 31a, 32a and a central recess 31b delimited radially by the annular body 31a, 32a.

[0121] The first and second flanges 31, 32 tightly connect the first and second skins 21, 22 to each other.

[0122] The first and second flanges 31, 32 each have an annular connecting surface 33a, 34a and an external peripheral annular edge 33b, 34b.

[0123] Each annular connecting surface 33a, 34a extends in a plane perpendicular to the main axis Y. Each annular connecting surface 33a, 34a has orifices 35 regularly distributed around the main axis Y. Each orifice 35 has an axis parallel to the main axis Y.

[0124] The second flange 32 is partially inserted between the first and second skins 21, 22 at the second end 20b of the membrane 19. In particular, the second flange 32 is partially inserted between the first and second collars 23, 24. The frustoconical annular surface 25b of the second collar 24 of the second skin 22 cooperates with a corresponding frustoconical annular surface of the second annular flange 32. Furthermore, the second radial annular surface 25c of the second collar 24 of the second skin 22 cooperates with the annular connecting surface 34a of the second annular flange 32 and the radial annular surface 27 of the first collar 23 cooperates with the surface axially opposite the annular connecting surface 34a of the second annular flange 32.

[0125] The first flange 31 is partially covered by the second skin 22.

[0126] The membrane 19 further comprises an annular spacer 36 on which the first flange 31 bears. The first flange 31 is thus supported by the annular spacer 36. In particular, the annular spacer 36 is arranged axially between the first flange 31 and the free annular surface 30 of the first skin 21. The annular spacer 36 has an annular body centered on the main axis Y and a central recess delimited radially by the annular body of the annular spacer 36. Preferably, the annular spacer 36 is housed inside the second skin 22, in the first shoulder 28a. The annular spacer 36 is for example metallic. The annular spacer 36 has for example at least one vent, and preferably two vents which open into the injection cavity C1. This makes it possible to create a vacuum in the fiber preform 100 in order to evacuate the excess resin during injection.The annular spacer 36 also makes it possible to improve the uniformity of the pressure in the fiber preform 100 during injection. In order to further reinforce the sealing of the membrane 19, the membrane 19 may further comprise an insert 37 located at the first longitudinal end 20a of the membrane 19 axially opposite the first and second collars 23, 24. The insert 37 is annular and centered on the main axis Y. It comprises an axial free end 37a and a radial free end 37b. The radial free end 37b may be connected to the axial free end by a median body 37c in the shape of an inverted L in longitudinal section. The axial free end 37a is inserted radially between the first and second skins 21, 22 and the radial free end 37b is interposed axially between the first flange 31 and the annular spacer 36.The median body 37c has a radial portion which extends radially inwards from the axial free end 37a and which bears on the first skin 21. The median body 37c also has an axial portion which extends axially from the radial portion and which bears against the reinforcement 36.

[0127] The mold 15 further comprises an injection cavity C1 for a resin and a compaction cavity C2 for the fiber preform.

[0128] The injection cavity C1 is annular and centered on the main axis Y. It is defined between the membrane 19 and the mandrel 16. The fiber preform 100 is located in this injection cavity C1. In a manner not illustrated, the mold 15 further comprises a port for injecting a resin into the injection cavity C1.

[0129] The compaction cavity C2 is located around the injection cavity C1. It is annular and centered on the main axis Y. The compaction cavity C2 is, according to an embodiment illustrated in FIG. 3, defined between the external wall 17 and the membrane 19.

[0130] According to the example of figure 4, the compaction cavity C2 is delimited by the first and second skins 21, 22. The sealing of the compaction cavity C2 is improved according to this embodiment.

[0131] The compaction cavity C2 can be filled with a compaction fluid. The mold 15 further comprises at least one injection port P1 for the compaction fluid into the compaction cavity C2. Each injection port P1 opens into the compaction cavity C2. Each injection port P1 is provided for example in one of the first or second flanges 31, 32 of the membrane 19. Each injection port P1 is provided for example in the first flange 31. Advantageously, the mold 15 comprises two injection ports P1. Each injection port P1 can be connected to a hydraulic coupler 38. The compaction fluid is for example oil.

[0132] In order to facilitate the circulation and purging of the compaction cavity C2, the mold 15 further comprises at least one outlet port P2 for the compaction fluid arranged in one of the first or second flanges 31, 32 of the membrane 19. Each outlet port P2 is for example arranged in the second flange 32. Each outlet port P2 is thus axially opposite each injection port P1. Advantageously, the mold 15 comprises two outlet ports P2. Each outlet port P2 can be connected to a hydraulic coupler 39.

[0133] As best seen in Figure 6a, when the membrane 19 is double-skinned 21, 22, in order to facilitate the circulation of the compaction fluid in the compaction cavity C2 located between the first and second skins 21, 22, the membrane 19 may comprise an annular groove 40 located between the first and second skins 21, 22. The annular groove 40 is centered on the main axis Y. In addition, the membrane 19 may comprise radial grooves 41 located at the second longitudinal end 20b. Each radial groove 41 extends radially from the second collar 24 towards the first longitudinal end 20a of the membrane 19. The radial grooves 41 are regularly distributed around the main axis Y. The membrane 19 comprises for example between two and ten radial grooves 41, preferably between two and six radial grooves, in particular six radial grooves 41.The radial grooves 41 are for example formed in shims to facilitate the passage of the compaction fluid throughout the area of ​​the membrane 19. Thanks to the double-skinned membrane 19 21, 22 in particular, it is possible to fill and empty the compaction cavity C2 while limiting the risks of leakage of the compaction fluid. Indeed, the compaction fluid is confined in the compaction cavity C2 which is delimited in a sealed manner by the first and second skins 21, 22 of the membrane 19.

[0134] Handling the membrane 19 for its installation around the fiber preform 100 is not easy. Indeed, its internal diameter may be less than the external diameter of the fiber preform 100 so that placing the membrane 19 around the fiber preform 100 requires considerable forces which may lead to rupture of the membrane 19.

[0135] In this context, the invention proposes a device 280 for handling the membrane 19 illustrated in FIG. 7. The device 280 comprises a bell 290 and a vacuum system 300.

[0136] The bell 290 extends around and along the main axis Y. It is mounted coaxially around the membrane 19 and delimits with the membrane 19 an annular space E.

[0137] The bell 290 comprises an annular body 310 centered on the main axis Y and which extends longitudinally between axially opposed first and second longitudinal ends 320a, 320b. The outer diameter of the first longitudinal end 320a is less than the outer diameter of the second longitudinal end 320b. The annular body 310 has a bell shape.

[0138] The first and second longitudinal ends 320a, 320b are respectively fixed to the first and second longitudinal ends 20a, 20b of the membrane 19. Preferably, in order to facilitate the mounting and fixing of the bell 290 on the membrane 19, the bell 290 further comprises first and second annular flanges 330, 340 located respectively at the first and second longitudinal ends 320a, 320b of the bell 290. Each first and second annular flange 330, 340 is respectively fixed to the first and second annular flanges 31, 32 of the membrane 19. The first and second annular flanges 330, 340 of the bell 290 and the first and second annular flanges 31, 32 of the membrane 19 are for example axially connected to each other for example by bolts 330a, 340a.By "connect axially", it is understood that each flange 31, 32, 330, 340 of the membrane 19 and of the bell 290 has an annular surface extending in a plane extending radially relative to the main axis Y and cooperating respectively together. Each bolt 330a, 340a has an axis parallel to the main axis Y.

[0139] Preferably, the second annular flange 340 of the bell 290 extends radially and forms a collar or an annular base.

[0140] Advantageously, the bell 290 further comprises sealing elements. The sealing elements comprise, for example, annular sealing members 350a, 350b carried respectively by the first and second annular flanges 330, 340 of the bell 290. Each sealing member 350a, 350b cooperates respectively with the first and second annular flanges 31, 32 of the membrane 19. Each sealing member 350a, 350b comprises, for example, at least one annular seal. Such sealing elements make it possible to improve the sealing of the annular space E. Furthermore, the sealing elements may comprise fixing rods 360a connecting the first annular flanges 310, 330 together and passing axially through the sealing member 350a. These fixing rods 360a together improve the sealing of the annular space E by compressing the sealing member 350a.

[0141] According to an exemplary embodiment, the bell 290 may comprise reinforcing ribs 370 regularly distributed around the main axis Y. The ribs 370 are located opposite the first longitudinal end 320a of the bell 290. The ribs 370 extend for example radially from the body 310 of the bell 290. The ribs 370 extend radially between the body 310 and the second annular flange 340 of the bell 290. Each rib 370 has a substantially triangular general shape. Each rib 370 may be perforated and therefore have an orifice 370a.

[0142] The vacuum system 300 is connected to the bell 290. The vacuum system 300 makes it possible to vacuum the annular space E. By “vacuum”, it is understood that the pressure in the annular space E is lower than the pressure outside the annular space E. The vacuum system 300 comprises at least one conduit 380 in fluid communication with the annular space E. The vacuum system 300 may comprise a plurality of conduits 380 regularly distributed around the main axis Y. Advantageously, the vacuum system 300 comprises two radially opposite conduits 380a, 380b. The number of conduits 380 depends mainly on the size of the annular space E which results from the surface area of ​​the membrane 19 to be vacuumed and the suction capacities of each conduit 380.

[0143] The or each conduit 380 extends axially along the annular body 310 of the bell 290. The or each conduit 380 may be connected at one of its longitudinal ends to a rib 370 and at its opposite longitudinal end to the body 310 of the bell 290. In particular, with reference to FIG. 9, the or each conduit 380 comprises a suction end 390, a connecting end 400 and a tube 410 connecting the suction end 390 to the connecting end 400. The suction end 390 is connected to a suction port 420 formed in the body 310 of the bell 290 and opening into the annular space E. The suction port 420 is located opposite the second longitudinal end 320b of the bell 290. The connecting end 400 is axially opposite the suction end 390. It is connected to a rib 370. The tube 410 has an internal air circulation passage.

[0144] Advantageously, the vacuum system 300 may further comprise one or more air outlets 430 opening into the annular space E. Preferably, the vacuum system 300 comprises two air outlets 430 which are radially opposite. The air outlets 430 each have an axis perpendicular to the main axis Y of the bell 290. These air outlets 430 are connected to the ducts 380 by a suction line 440. The suction line 440 advantageously extends over an angular sector around the main axis Y. The angular sector extends for example at an angle of between 30° and 90° around the main axis Y. Each suction line 440 is located opposite the first longitudinal end 320a of the bell 290. Each suction line 440 advantageously passes through at least one rib 370 through the orifice 370a.Each suction line 440 is connected on the one hand to a conduit 380 and on the other hand to an air outlet 430 via a connector 450, for example a T-connector.

[0145] The vacuum system 300 may further comprise a pumping device 460 connected to the conduit 380 via the suction line 440 for suctioning air from the annular space E. The pumping device 460 may be connected to each air outlet 440 via a pumping line 470. Each air outlet 440 is connected to a pumping line 460 and to a suction line 440 via a T-connector for example.

[0146] The vacuum system 300 thus makes it possible to create a vacuum or to evacuate the annular space E located radially between the membrane 190 and the bell 290. This makes it possible to expand the membrane 19 radially outwards. The expansion rate of the membrane 19 thanks to such evacuation of the annular space E is for example between 5% and 10%. The expansion rate represents the ratio between the difference in internal diameter of the membrane 19 after evacuating the annular space E and the internal diameter of the membrane 19 before evacuating the annular space E. It is thus understood that thanks to the bell 290 of the invention, it is possible to increase the internal diameter of the membrane 19 prior to its deposition around the fiber preform 100.This makes it easier to handle when installing it around the fiber preform 100 for the purpose of manufacturing the fan casing 8 by injection molding.

[0147] According to an embodiment illustrated in FIG. 12, at least one positioning member 500 is mounted inside the bell 290. In particular, the positioning member 500 is mounted around the membrane 19 and preferably on the side of the second longitudinal end 320b of the bell 290.

[0148] The positioning member 500 may be annular and mounted coaxially around the second longitudinal end 20b of the membrane 19. The positioning member 500 may be in the form of a rod.

[0149] The positioning member 500 may comprise a thermoplastic polymer material or a metallic material.

[0150] The positioning member 500 makes it possible to limit or even eliminate deformation of the membrane 19 during the evacuation of the annular space E. Thanks to this positioning member 500, during the evacuation, the membrane 19 deforms mainly radially relative to its axis. This makes it possible to preserve the geometry of the membrane 19 after the evacuation and to maintain correct positioning around the fiber preform 100.

[0151] According to an exemplary embodiment, several positioning members 500 are mounted inside the bell 290, each positioning member 500 being mounted around the membrane 19. For example, two, three or more positioning members 500 are mounted inside the bell 290 and around the membrane 19.

[0152] A method of manufacturing the fan casing 8 will now be described with reference to FIG. 11. This manufacturing method applies to any casing of the turbomachine 1, such as the intermediate casing 9.

[0153] The manufacturing process includes the following steps:

[0154] (a) providing an assembly comprising the bell 290 mounted around the membrane 19,

[0155] (b) create a vacuum in the annular space E,

[0156] (c) provide the mandrel 16,

[0157] (d) arranging the fiber preform 100 around the mandrel 16, (e) arranging the assembly around the fiber preform 100, the mandrel 16 and the membrane 19 defining the injection cavity C1 of the resin in which the fiber preform 100 is located,

[0158] (f) injecting the compaction fluid into the compaction cavity C2 located between the external wall 17 and the membrane 19 or between the first and second skins 21, 22 of the membrane 19,

[0159] (g) injecting the resin into the injection cavity C1, and

[0160] (h) polymerizing the resin to form the matrix.

[0161] In step (g), the polymeric material is, for example, injected under pressure. It is, for example, injected at a pressure of between 5 bars and 20 bars, in particular between 5 bars and 15 bars.

[0162] In step (h), the mold 15 is subjected to a temperature between 100°C and 200°C. The mold 15 is for example placed in an oven for the polymerization of the resin.

[0163] The evacuation of the annular space E makes it possible to expand the membrane 19 radially outwards. Thus, the membrane 19 has, after the evacuation of this annular space E, an internal diameter greater than the internal diameter of the membrane 19 before this evacuation.

[0164] Thanks to such expansion, the membrane 19 has an internal diameter large enough to be easily installed around the fiber preform 100 for the manufacture of the casing 8, 9 by injection molding.

[0165] Thanks to the device 280 of the invention, the handling of the membrane 19 is facilitated and it is therefore no longer necessary to implement significant forces during its installation around the fiber preform 100. In addition, the device 280 is particularly advantageous in the case where the membrane 19 has the first and second skins 21, 22. Indeed, the presence of the first and second skins 21, 22 accentuates the difficulty of handling the membrane 19. It is difficult to access the first skin 21 which is the innermost, that is to say which is radially closest to the main axis Y. The fact of implementing significant tensile forces by pulling only on the second skin 22, which is the outermost, causes a detachment of one of the skins 21, 22 and therefore the rupture of the membrane 19.Thanks to the device 28 of the invention, significant tensile forces are avoided for positioning the membrane 19 and the integrity of the membrane 19 is thus preserved during its installation.

Claims

Tl CLAIMS 1. Set including: - an annular membrane (19), in particular for the manufacture of an annular casing (8, 9) of an aircraft turbomachine (1), and - a device (280) for handling the membrane (19), characterized in that the device (280) comprises: - an annular bell (290) which extends around a main axis (Y) and which is mounted around the membrane (19), the bell (290) comprising a first longitudinal end (320a) fixed to a first longitudinal end (20a) of the membrane (19), a second longitudinal end (320b), opposite the first longitudinal end (320a), and fixed to a second longitudinal end (20b) opposite the membrane (19), and - a system for creating a vacuum (300) of an annular space (E) located between the bell (290) and the membrane (19) in order to expand the membrane (19) radially outwards.

2. Assembly according to the preceding claim, characterized in that the bell (290) comprises a first annular flange (330) at its first longitudinal end (320a), fixed on a first annular flange (31) corresponding to the first longitudinal end (20a) of the membrane (19), and a second annular flange (340) at its second longitudinal end (320b), fixed on a second annular flange (32) corresponding to the second longitudinal end (20b) of the membrane (19).

3. Assembly according to the preceding claim, characterized in that the first and second annular flanges (330, 340) of the bell (290) carry sealing elements (350a, 350b) cooperating with the first and second annular flanges (31, 32) of the membrane (19).

4. Assembly according to any one of the preceding claims, characterized in that the bell (290) comprises an annular body (310) centered on the main axis (Y) and axial reinforcing ribs (370) regularly distributed around the main axis (Y).

5. Assembly according to any one of the preceding claims, characterized in that the vacuum system (300) comprises at least one conduit (380) in fluid communication with the annular space (E).

6. Assembly according to all of claims 4 and 5, characterized in that the conduit (380) extends along the annular body (310) and is connected to one of the ribs (370).

7. Assembly according to any one of the preceding claims, characterized in that the membrane (19) forms a bladder and comprises first and second coaxial annular skins (21, 22), respectively internal and external, which are connected together in a sealed manner respectively to the first and second longitudinal ends (20a, 20b) of the membrane (19).

8. Assembly according to one of the preceding claims, characterized in that the membrane (19) comprises a material comprising a silicone and possibly reinforcing fibers.

9. Assembly according to any one of the preceding claims, characterized in that it comprises at least one positioning member (500) located inside the bell (290) and around the membrane (19).

10. Assembly according to any one of the preceding claims, characterized in that it comprises two positioning members (500), each positioning member (500) being located inside the bell (290) and around the membrane (19).

11. Method for manufacturing an annular casing (8, 9) of an aircraft turbomachine (1), the casing (8, 9) comprising a composite material comprising a polymer matrix and an annular fibrous preform (100) embedded in the matrix, characterized in that the method comprises the following steps: (a) providing an assembly according to one of the preceding claims, (b) create a vacuum in the annular space (E), (c) providing an annular mandrel (16), (d) arranging the fibrous preform (100) coaxially around the mandrel (16), and (e) arranging the assembly around the fibrous preform (100), the mandrel (16) and the membrane (19) defining an injection cavity (C1) of a resin in which the fibrous preform (100) is located.

12. Method according to the preceding claim, characterized in that it further comprises the following steps: (f) injecting a compaction fluid into a compaction cavity (C2) located around the injection cavity (C1), and (g) inject the resin into the injection cavity (C1).

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