FR3063674A1 - MECHANICAL PRESSURE APPLICATION DEVICE, IMPREGNATION METHOD, AND BONDING METHOD - Google Patents

Abstract

Device (100-1) for applying a mechanical pressure on at least one part (1), the device (100-1) comprising - a first chamber (2-1) intended to contain said at least one part ( 1), - a second chamber (3-1) for containing a pressurizing fluid, - a deformable membrane (30-1) separating the first chamber (2-1) from the second chamber (3-1), fluid injection means (5-1) in the second chamber (3-1), the deformable membrane (30-1) comprising at least a first portion (30b), a second portion (30c) and a zone transition device (30e) defining a wedge (60-1) between the first portion (30b) and the second portion (30c), this device (100-1) being characterized in that the membrane comprises an extra thickness (70-1) present on the corner (60-1) of the transition zone (30e).

Description

(57) Device (100-1) for applying mechanical pressure to at least one part (1), the device (100-1) comprising

- a first chamber (2-1) intended to contain said at least one part (1),

- a second chamber (3-1) intended to contain a pressurizing fluid,

- a deformable membrane (30-1) separating the first chamber (2-1) from the second chamber (3-1),

- means for injecting (5-1) the fluid into the second chamber (3-1), the deformable membrane (30-1) comprising at least a first portion (30b), a second portion (30c) and a zone transition (30e) defining a corner (60-1) between the first portion (30b) and the second portion (30c), this device (100-1) being characterized in that the membrane comprises an additional thickness (70-1) present on the corner (601) of the transition zone (30e).

Background of the invention

The invention relates to a device for applying mechanical pressure to at least one part, a method of impregnating a part forming a fibrous texture and a method of bonding between at least two parts.

In the present description, the term “part” can notably designate a part made of composite material, a metal part or even a part forming a fibrous texture intended to form a fibrous reinforcement of a composite material.

There is a known use of the “poly-flex” process for the manufacture of composite materials. A fibrous texture is draped over a tool comprising a surface having the desired profile of a final product. The texture is covered by a deformable waterproof membrane and resin is then injected between the membrane and the texture. On the other side of the membrane, an isostatic pressure is exerted on the membrane by a fluid which generates a deformation of the face of the membrane located opposite the texture. This fluid forces the resin to penetrate between the fibers of the texture and maintains a pressure during the baking phase of the resin.

Another known use of the “poly-flex” process is to bond a plurality of pieces together. For example, two parts are assembled in the same chamber using a layer of adhesive interposed between them. The chamber in which these parts are placed is delimited between a support and a deformable waterproof membrane. One side of the membrane thus faces the assembled parts. On the other side of the membrane, an isostatic pressure is exerted on the membrane by a fluid which generates a deformation of the face of the membrane located opposite the assembled parts. The membrane is then configured so that after application of the liquid its internal face has a complementary shape of at least one of the facing pieces, thus allowing the pieces to be bonded by the layer of adhesive.

However, the methods described above may have certain limits, in particular for parts with complex geometries, for example for parts comprising singularities such as recesses, grooves, curved angles and more generally corners.

By way of example, to manufacture is an annular casing made of composite material, such as an aeronautical turbomachine casing, the fiber preform of this casing typically has a central ferrule whose width extends in an axial direction between two annular flanges, these flanges extending in a radial direction towards the outside of the central ferrule. Such a fibrous preform then has between each flange and the central zone a transition zone, each of these transition zones thus forming a corner. During the implementation of the “poly-flex” process for the manufacture of such a casing, particularly during the application of the isostatic pressure on the membrane, the membrane may exert a lower force on the corners of the fiber preform compared to the pressure it exerts on the rest of the preform, especially on the central area and the flanges. The corners indeed correspond to areas of the fibrous preform which are more difficult to reach by the membrane during its deformation. Thus, the corners of the fiber preform can therefore be less compacted by the membrane. More generally, for any part comprising corners, it can sometimes be observed a lower fiber volume ratio in the corner areas of this part compared to a theoretical value. The part thus produced may possibly have poorer mechanical properties in its corner areas.

Similarly for the bonding of a plurality of parts, at least two parts assembled together may have a singularity resulting from their stacking, for example a recess or a corner facing the deformable membrane delimiting the chamber in which they are positioned. This area of singularity can be more difficult to reach by the membrane during its deformation. It is thus possible that during the application of the isostatic pressure of the fluid on the membrane, the membrane marries less the singularity zone formed by the assembly of the parts. It may thus result that the bonding of the assembled parts has a lower mechanical strength in the corner area formed by the assembly of these parts.

Subject and summary of the invention

The object of the present invention is to remedy the aforementioned drawbacks.

To this end, the invention provides a device for applying mechanical pressure to at least one part, the device comprising

- a first chamber intended to contain said at least one room,

- a second chamber intended to contain a pressurizing fluid,

- a deformable membrane separating the first chamber from the second chamber,

means for injecting the fluid into the second chamber, the deformable membrane comprising at least a first portion, a second portion and a transition zone defining a corner between the first portion and the second portion, the membrane further comprising an additional thickness present on the corner of the transition zone.

This device is particularly advantageous in that it makes it possible to apply via the deformable membrane a homogeneous mechanical pressure on one or more parts present in the first chamber. In particular, the purpose of the additional thickness formed on the membrane is to be able to come to bear on a corresponding corner of a part present in the first chamber or on a corner formed by a plurality of parts present in the first chamber. The extra thickness also makes it possible to form a corner of the deformable membrane. This corner is designed so as to have a shape complementary to a corner specific to a part, or formed by a plurality of parts. The creation of the extra thickness then allows vis-à-vis the state of the art to increase the complementarity between the deformable membrane and one or more parts, ensuring a better distribution of the membrane on them when they are put in touch.

Thus, after introduction of a compression fluid in the second chamber, the deformable membrane comes to apply mechanical pressure to one or more parts present in the first chamber, the extra thickness then making it possible to exert mechanical pressure on a corner suitable for a part or resulting from the assembly of a plurality of parts. The proposed device therefore allows vis-à-vis the state of the art to be able to come to exert an optimal mechanical pressure on any singularity or corner present on a part or formed by the assembly of a plurality of parts. Such a device can in particular be used to exert mechanical pressure allowing the resin impregnation of a fibrous texture present in an impregnation chamber. Advantageously, for the impregnation of a fibrous texture, the proposed device makes it possible to exert a homogeneous pressure on the whole of the fibrous texture, in particular when it has corner areas. There is thus obtained a homogeneous compaction of the fibrous texture and after densification thereof a part having a volume ratio of homogeneous fiber and optimal mechanical properties. The proposed device can also be used for bonding in a same chamber a plurality of parts when this bonding requires the application of mechanical pressure on the parts by a deformable membrane. The device then makes it possible to apply uniform pressure over the entire bonding surface of the assembled parts and thus makes it possible to obtain bonding between these parts having optimal mechanical strength.

According to another aspect, for this device, the additional thickness is formed by an element attached to the deformable membrane.

According to another aspect, for this device, the additional thickness is formed monolithically with the deformable membrane.

According to another aspect, in this device, the deformable membrane is impermeable.

According to another aspect, in this device, the pressurizing fluid is an incompressible fluid.

According to another aspect, in this device, the first chamber is delimited by a support on which said at least one part is intended to be positioned and the deformable membrane is located around the first chamber.

The invention also provides a method of impregnating a part forming a fibrous texture with an impregnating composition implementing a work a device as summarized above, the fibrous texture having at least a first part, a second part. and an intermediate zone defining a corner between the first part and the second part, and the method comprising the following steps:

positioning of the fibrous texture in the first chamber, the fibrous texture being present opposite the deformable membrane,

- introduction of an impregnation composition into the first chamber between the fibrous texture and the deformable membrane,

- introduction of a pressurizing fluid into the second chamber in order to apply via said membrane a pressure on the fibrous texture so as to impregnate it with the impregnation composition, the excess thickness of the deformable membrane being supported on the corner of the fibrous texture when applying pressure.

According to another aspect, for this device, the fibrous texture constitutes a fibrous preform and is intended to form a fibrous reinforcement of an aeronautical engine casing, in particular of a fan casing, said fibrous texture being maintained in shape on a support. so as to define a central ferrule extending in width in an axial direction between a first annular flange and a second annular flange, the first flange and the second flange extending in a radial direction towards the outside of the central ferrule, a first intermediate zone defining a first corner between the first flange and the central ferrule, a second intermediate zone defining a second corner between the second flange and the central ferrule, the deformable membrane being located around the first chamber, the deformable membrane comprising in addition to a first annular central portion extending in an axial direction between a second annular portion and a third sixth annular portion, the second portion and the third portion extending in a radial direction outward from the first portion, a first transition zone comprising an extra thickness and defining a corner between the first portion and the second portion, a second transition zone comprising an additional thickness and defining a corner between the first portion and the third portion, so that the additional thickness of the first transition zone and the additional thickness of the second transition zone respectively come to bear on the first corner and the second corner of the fibrous texture when applying pressure.

The invention also provides a method of bonding between at least two parts, implementing the device summarized above, the method comprising the following steps:

- assembly of at least a first part on a second part, at least one layer of adhesive being present between the two assembled parts,

placement of the pieces in the first chamber, the deformable membrane being opposite the assembled pieces, the assembly of said at least first piece on the second piece forming at least one corner adjacent to the first piece and to the second piece, said at minus one corner being defined by the superposition of these parts,

- introduction of a pressurizing fluid into the second chamber in order to impose via said membrane a pressure on the assembled parts allowing their bonding by means of the adhesive layer, the excess thickness of the deformable membrane coming to bear on the corner defined by the first part and the second part when the pressure is applied.

Brief description of the drawings

Other characteristics and advantages of the invention will emerge from the following description of particular embodiments of the invention, given by way of nonlimiting examples, with reference to the appended drawings, in which:

FIG. 1 schematically and partially represents a sectional view of a fibrous texture placed in a device according to one embodiment,

FIG. 1A illustrates a variant of deformable membrane present in the device of FIG. 1,

FIG. 2 represents, schematically and partially, the assembly according to FIG. 1 after introduction of an impregnation composition,

FIGS. 3A and 3B show, schematically and partially, the assembly according to FIG. 2 respectively during and after introduction of a compression fluid,

FIG. 4 schematically and partially represents a view of two pieces to be bonded placed in a device according to one embodiment,

- Figure 5 shows, schematically and partially, the assembly according to Figure 4 after introduction of a compression fluid.

Detailed description of embodiments

FIG. 1 illustrates a first embodiment of a device

100-1 of mechanical pressure application according to the invention, intended here for the impregnation of a part forming a fibrous texture 1 with an impregnation composition. The fibrous texture 1 is intended to form a fibrous reinforcement of a composite material, in particular of the ceramic matrix composite (CMC) or organic matrix composite (CMO) type.

The fibrous texture 1 is produced in a known manner by weaving by means of a jacquard type loom on which a bundle of warp threads and / or strands has been placed in a plurality of layers, the warp threads being linked by weft threads or vice versa. The fibrous texture 1 can be produced by stacking layers or folds obtained by two-dimensional weaving (2D). The fibrous texture 1 can also be produced directly in one piece by three-dimensional weaving (3D). The term “two-dimensional weaving” is understood here to mean a conventional weaving mode by which each weft thread passes from one side to the other of threads of a single layer of warp or vice versa.

The term “three-dimensional weaving” or “3D weaving” or “multilayer weaving” is understood here to mean a weaving method by which at least some of the weft threads link warp threads on several layers of warp threads or vice versa according to weaving corresponding to a weaving weave which can in particular be chosen from one of the following weaves: interlock, multi-canvas, multi-satin and multi-twill.

The device 100-1 comprises a first chamber 2-1, here forming an impregnation chamber, intended to contain the fibrous texture 1. The first chamber 2-1 is separated by a deformable membrane 30-1 from a second chamber 3 -1, here a compaction chamber, this second chamber 3-1 being intended to contain a pressurizing fluid. The device 100-1 further comprises respectively means 4, 5-1 for injecting an impregnation composition and pressurizing fluid.

In the particular example illustrated here, the fibrous texture 1 constitutes a fibrous preform and is intended to form a fibrous reinforcement of an aeronautical engine casing, for example a fan casing. Thus in FIG. 1, the fibrous texture 1 and the device 100-1 have a symmetry of revolution with respect to an axis X-X.

The device 100-1 comprises a rigid support 6 on which the fibrous texture 1 is intended to be positioned. The first chamber 21 is thus delimited by the support 6 and the deformable membrane 30-1 situated around the latter. The first chamber 2-1 is, moreover, delimited by lateral walls 6a and 6b of the support 6, these walls extending here in a radial direction relative to the axis X-X. The deformable membrane 30-1 has an internal face 30a situated opposite the fibrous texture 1. The second chamber 3-1, separated from the first chamber 2-1 by the deformable membrane 30-1 can in turn be delimited by a cover 7.

The deformable membrane 30-1, in particular its internal face 30a, can be deformed in the direction of the support 6 when sufficient pressure is exerted on it. In order to allow this deformation, the membrane may include, in particular be made of, a material chosen from: silicones reinforced or not, thermoplastic polymers, for example polyamide, polyethylene terephthalate (PET), teflon® (PTFE ) or polyimide, and mixtures thereof, this list not being exhaustive. The deformable membrane 30-1 can be waterproof or permeable. If the deformable membrane 30-1 is permeable, it is produced with a low porosity in order to avoid any transfer of fluid between the first chamber 2-1 and the second chamber 3-1.

The fibrous texture 1 can be draped over a tool comprising a surface having the desired profile of the final fibrous reinforcement. The shaped fibrous texture 1 thus constitutes a fibrous preform. In the example illustrated, the fibrous texture 1 is maintained on the support 6, so as to define a central ferrule extending in width along the axis X-X between a first annular flange 1b and a second annular flange. The first flange lb and the second flange le extend, with respect to the axis XX, in a radial direction towards the outside of the central ferrule la, a first intermediate zone ld defining a first corner 50-1 between the first flange lb and the central ferrule la, a second intermediate zone defining it a second corner 50-2 between the second flange le and the central ferrule la.

As explained during the introductory part, any singularity of a part, for example a groove, a recess, a curved angle, and more generally any corner is in practice more difficult to reach by the membrane during its deformation. For example, the first corner 50-1 and the second corner 50-2 of the fibrous texture 1 may be here likely to be less compacted by the deformable membrane 30-1 compared to the central shell 1a.

To counter this risk, in accordance with the invention the deformable membrane 30-1 comprises one or more extra thicknesses on one or more predetermined corner areas of this membrane. Each additional thickness is produced with the deformable membrane so as to come to bear on a corresponding corner of at least one part, during the application of a pressurizing fluid to the deformable membrane.

Thus, in the example illustrated the deformable membrane 30-1 comprises a first annular central portion 30b extending in the axial direction XX between a second annular portion 30c and a third annular portion 30d, the second portion 30c and the third portion 30d extending in a radial direction towards the outside of the first portion 30b. A first transition zone 30e comprises an extra thickness 70-1 and defines a corner 60-1 between the first portion 30b and the second portion 30c. A second transition zone 30f includes an extra thickness 70-2 and defines a corner 60-2 between the first portion 30b and the third portion 30d. In accordance with the invention the extra thicknesses 70-1, 70-2 are produced so as to come to bear respectively on the first corner 50-1 and the second corner 50-2 of the fibrous texture 1 during the application of the pressure pressurizing fluid on the deformable membrane 30-1.

Figure 1 shows an enlargement medallion of the second transition zone 30f. As can be seen on this enlargement, an extra thickness 70-2 is here formed by an element attached to the deformable membrane 30-1. For the sake of clarity, it is specified here that for any element attached to the deformable membrane 30-1, the expression “excess thickness” 70-1, 70-2 means the respective association of the thickness of the element with all or part of the thickness of the deformable membrane 30-1.

In the case of an added element, the material of the element can be chosen identical to that of the membrane (eg silicone). Alternatively, the material of the insert can be made of a material separate from that of the membrane. The material of the insert is then chosen so as to have elasticity properties close to the membrane in order to be able to follow the deformation movements of the latter and is chosen so as to have good adhesion properties to that -this.

The insert is, for example, manufactured independently of the deformable membrane 30-1 and then bonded thereto, or thermally assembled with the deformable membrane 30-1 during a common baking step, so as to form the extra thickness 70-2.

In another embodiment illustrated on the medallion of FIG. IA, an additional thickness 70-3 is formed in a monolithic manner with the deformable membrane 30-1.

Furthermore, the extra thicknesses 70-1, 70-2, 70-3 are produced so as not to mark or deform the fibrous texture 1 when these extra thicknesses come to bear on the corners 50-1, 50-2 of the fibrous texture 1. To do this, the extra thicknesses 70-1, 70-2, 70-3 of the deformable membrane 30-1 may possibly have thinned edges at the junctions of the first central portion 30b with the transition zones 30e, 30f and 'at the junctions of the second and third portions 30c, 30d with the transition zones 30e, 30f.

The extra thicknesses 70-1, 70-2, 70-3 of the deformable membrane 301 are here produced in response to the particular example of a fibrous texture 1 of a casing comprising two corner areas 50-1, 50-2 . Two extra thicknesses 70-1, 70-2 are therefore produced here intended to come into respective abutment of two corners 50-1, 50-2 of the fibrous texture 1. This number of extra thicknesses is however here given only for illustrative purposes and is a function of the part to be manufactured. It will also be noted that the terms “second” portion 30c, “third” portion 30d, “first” transition zone 30e and “second” transition zone 30f of the deformable membrane 301 are used here only for descriptive purposes. In fact, the “second” or “third” portions can either refer to the reference numerals 30c, 30d. Likewise, the “first” transition zone or “second” transition zone can equally correspond to the numerical references 30e, 30f.

Thus, more generally, an additional thickness is produced (eg one of the additional thicknesses 70-1 or 70-2) with a deformable membrane for any part comprising at least a first part (eg: the central ferrule la), a second part (eg : one of the flanges lb or le) and an intermediate zone (ex: the intermediate zone ld or le) defining a corner (ex: one of the corners 50-1 or 50-2) between the first part and the second part. In another example, not illustrated, the first part, the second part and the intermediate zone defining a corner can be constitutive of a groove formed in a mechanical part. A deformable membrane is then produced formed of at least a first portion (eg the first central portion 30b), a second portion (eg one of the portions 30c or 30d) and a transition zone (eg a transition zones 30e or 30f) comprising an additional thickness and defining a corner between the first portion and the second portion, so that the additional thickness of this membrane comes to bear on the corner of the part during the deformation of the membrane . One could add an element to the transition zone between the first portion and the second portion of an already formed membrane, for example iso-thickness, or directly form, for example by molding, a monolithic membrane with its extra thickness. Thus, each additional thickness makes it possible to form a corner of the deformable membrane. This corner is designed so as to have a shape complementary to a corner specific to a part, or formed by a plurality of parts. The creation of the extra thickness then allows vis-à-vis the state of the art to increase the complementarity between the deformable membrane and one or more parts, ensuring a better distribution of the membrane on them when they are put in touch.

FIG. 2 illustrates the device 100-1 of FIG. 1 after introduction of an impregnation composition 8 in the form of an organic resin in the first chamber 2-1.

The resin is, as illustrated, introduced into the free volume of the first chamber 2-1 using the injection means 4. In the example illustrated, the resin was injected after placing the fibrous texture 1 on the support 6 between the fibrous texture 1 and the deformable membrane 30-1. In a variant not shown, the impregnation composition 8 may be present between the fibrous texture 1 and the support 6. Thus, the impregnation composition 8 may, in a variant not shown, have been introduced into the first chamber 2- 1 before placing the fiber texture 1 over it. Once the resin has been injected, it can be superimposed on the fibrous texture 1 over substantially the entire length thereof.

Once the resin is present in the first chamber 2-1, a pressurizing fluid 9-1, for example an incompressible fluid such as oil, is introduced into the second chamber 3-1 by the injection means 5 -1 fluid. The assembly obtained during and after the introduction of the fluid 9-1 into the second chamber 3-1 is shown respectively in FIGS. 3A and 3B. The fluid 9-1 is applied to the deformable membrane 30-1 on the side opposite to the first chamber 2-1. In other words, once the fluid 9-1 applied to the deformable membrane 30-1, the deformable membrane 30-1 is present between the first chamber 2-1 and the fluid 9-1. In the example illustrated, the fluid 9-1 is applied to the deformable membrane 30-1 once the injection of the resin 20 into the first chamber 2-1 is complete.

The applied fluid 9-1 exerts pressure on the deformable membrane 30-1. The isostatic pressure of the fluid 9-1 forces the impregnation composition 8, here an organic resin, through the fibrous texture 1, deforms the deformable membrane 30-1 towards the support 6 by pushing the latter in the direction of the fibrous texture 1. The deformation of the deformable membrane 30-1 during the application of the fluid 9-1 generates a reduction in the volume of the first chamber 2-1, as can be seen in FIG. 3A. In parallel, the impregnation front of the resin in the fibrous texture 1 progresses in the thickness of the texture due to the pressure exerted by the deformable membrane 30-1. In FIG. 3A, the fibrous texture 1 is represented before the end of its impregnation by the impregnation composition 8. The impregnation composition 8 then occupies a gradually reduced volume in the first chamber 2-1 between the deformable membrane 30- 1 and the fibrous texture 1. At this time, the deformable membrane 30-1 is not yet in contact with the fibrous texture 1.

In FIG. 3B, the application of the fluid 9-1 deforms the deformable membrane 30-1 until it comes into contact with the fibrous texture 1. The fibrous texture 1 is then completely impregnated with the resin. Advantageously and in accordance with the invention, the corners 60-1, 60-2 comprising the extra thicknesses 70-1, 70-2 of the deformable membrane 30-1 then come to bear respectively against the first corner 50-1 and the second corner 50 -2 of the fibrous texture 1. The deformable membrane 30-1 thus exerts a force distributed over all of the zones of the fibrous texture 1, ensuring optimal compaction of the fibers over the whole of the fibrous texture 1. This thus gives an optimal fiber volume rate over the entire fibrous texture 1, in particular in the corner areas 50-1, 50-2 thereof. The fibrous reinforcement obtained from this Fibrous texture 1 will thus have optimal mechanical properties.

Once the fibrous texture 1 is completely impregnated with the resin, in known manner the resin can subsequently undergo a curing step during which the isostatic pressure of the fluid 9-1 propagates in the fibrous texture 1 impregnated with the resin. The pressure exerted by the fluid 9-1 is maintained until the crosslinking of the resin. A composite material is thus obtained, here forming a casing, comprising a fibrous reinforcement densified by a matrix. The device 100-1 may include a heating member (not shown) making it possible to carry out the heat treatment making it possible to transform the resin into a densification matrix.

FIG. 4 illustrates another embodiment of a device 1002 for applying mechanical pressure according to the invention, intended here to allow the bonding of at least two parts. The device 100-2 comprises a first chamber 2-2 intended to contain a plurality of parts to be bonded together. The first chamber 2-2 is separated by a deformable membrane 30-2 from a second chamber 3-2, here a compaction chamber, this second chamber 3-2 being intended to contain a pressurizing fluid. The device 100-2 further comprises means 5-2 for injecting a pressurizing fluid.

In the example illustrated in FIG. 4, two parts 10, 11 are present in the first chamber 2-2.

A first part 10 is located opposite a part of the internal face 30g of the deformable membrane 30-2 delimiting the first chamber 2-2. At least one layer of adhesive 31 is present between the first part 10 and a second part 11 and is in contact with them. The first part 10 is present between the layer of adhesive 31 and part of the deformable membrane 30-2. A part of the second part 11, on which the layer of adhesive 31 and the first part 10 are not present, is situated opposite a part of the internal face 30g of the deformable membrane 30-2. The internal face 30g of the deformable membrane 30-2 is located on the side of the first chamber 2-2. The first chamber 2-2 can also be delimited by a seal 32. The deformable membrane 30-2 is located between the first chamber 2-2 and the second chamber 3-2, the second chamber 3-2 can be bounded by a support 33.

The deformable membrane 30-2, in particular its internal face 30g, can be deformed in the direction of the parts 10, 11 assembled in the first chamber 2-2 when sufficient pressure is exerted on it. In order to allow this deformation, the deformable membrane 302 may include, in particular be made of one of the materials previously proposed for the production of the deformable membrane 30-1. The deformable membrane 30-2 can be waterproof or permeable. If the deformable membrane 30-2 is permeable, it is produced with a low porosity in order to avoid any transfer of fluid between the first chamber 2-2 and the second chamber 3-2.

In the example illustrated, only part of the second part 11 on which the first part 10 is intended to be glued is present in the first chamber 2-2. The second part 11 is for example a turbomachine blade and the first part 10 is an element intended to constitute, once glued, a leading edge. The turbomachine vane can, for example, be made of composite material and comprise a fibrous carbon reinforcement and densified by an epoxy matrix. The element intended to constitute a leading edge may be made of metallic material.

It is not beyond the scope of the present invention when the parts to be bonded are, for example, each of composite material and each comprise a fibrous carbon reinforcement and densified by an epoxy matrix. The parts to be bonded may also include one or more sandwich materials of the honeycomb or foam type. It is also possible in the context of the methods according to the invention to bond between a plurality of parts, each being of metallic material or alternatively, for example, of glass, wood or ceramic.

In another example not shown, the first part 10 and the second part 11 may in their entirety be present in the first chamber 2-2.

As can be seen in FIG. 4, the first part 10 is assembled on a part of the second part 11. The superposition of the first part 10 with the second part 11 thus defines two corners 50-3, 50-4 adjacent to these parts 10.11. As explained above, any singularity specific to at least one part, or in this example any singularity defined between at least two parts 10, 11 is in practice more difficult to reach by the deformable membrane 30-2 when the latter is deformed under pressure. a compression fluid. In the example illustrated, the corners 50-3, 50-4 resulting from the superposition of the first part 10 on a part of the second part 11 are likely to be less compacted by the deformable membrane 30-2 compared to the other surfaces. pieces 10, 11 facing the internal face 30g of the deformable membrane 30-2.

To counter this risk and in accordance with the invention, the deformable membrane 30-2 comprises one or more extra thicknesses formed on one or more transition zones of this membrane. Each additional thickness is made on the membrane so as to come to bear on a corresponding corner formed by one or more parts.

In the example illustrated, the membrane comprises two extra thicknesses 70-4, 70-5 intended to come into respective abutment on the corners 50-3, 50-4 defined between the parts 10,11, these extra thicknesses coming into abutment during the application of a pressurizing fluid to the deformable membrane 30-2. The deformable membrane 30-2 here comprises a first portion 30h, a second portion 30i and a third portion 30j. The first portion 30h is separated respectively from the second portion 30i and from the third portion 30j by transition zones 30k, 30I. The transition zone 30k defines a corner 60-3 between the first portion 30h and the second portion 30i. The transition zone 30I defines a corner 60-4 between the first portion 30h and the third portion 30j.

In accordance with the invention, the extra thicknesses 70-4, 70-5 are formed in the transition zones 30k, 30I, so that these extra thicknesses 70-4, 70-5 come to bear on the corners 50-3, 50-4 defined between the parts 10,11 during the deformation of the deformable membrane 30-2.

Once again each additional thickness 70-4, 70-5 can be formed in a monolithic manner, as illustrated in FIGS. 4 and 5, or result from the association of an added element with the deformable membrane 302. In the case of an added element, the material of the element can be chosen to be identical to that of the deformable membrane 30-2 or be produced using a separate material having similar elasticity properties.

In addition, the extra thicknesses 70-4, 70-5 are produced so as not to mark or deform the first part 10 and the second part 11. To do this, the extra thicknesses 70-4, 70-5 may by way of example present thinned edges at the junctions of the first portion 30h with the transition zones 30k, 301 and at the respective junctions of the second and third portions 30i, 30j with the transition zones 30k, 301.

The extra thicknesses 70-4, 70-5 of the deformable membrane 30-2 are here produced in response to the particular example of the bonding of two parts 10, 11 forming two corners 50-3, 50-4. Two extra thicknesses 70-4, 70-5 are therefore produced here intended to come into respective support of the two corners 50-3, 50-4 defined between the parts 10, 11. This number of excess thicknesses and corners is however not given here. for illustrative purposes only.

More generally, an additional thickness is produced on the deformable membrane 30-2 for any corner resulting from the assembly or the superposition of at least two parts. The deformable membrane 30-2 is then produced so as to consist of at least a first portion, a second portion and a transition zone comprising an extra thickness and defining a corner between the first portion and the second portion. The additional thickness is produced so as to come to bear on the wedge formed by the assembly of said at least two parts during the deformation of the membrane.

FIG. 5 illustrates the device 100-2 of FIG. 1 after introduction by the injection means 5-2 of a pressurizing fluid 9-2, for example an incompressible fluid such as oil, into the second room 3-2. The fluid 9-2 was introduced into the second chamber 3-2 via an inlet orifice 33a for the fluid. An outlet orifice 33b for the pressurizing fluid 9-2 may also be present in order to evacuate the fluid 9-2 once the bonding process has ended. The fluid inlet 33a and outlet 33b orifices can, as shown, be formed in the support 33.

The fluid 9-2 applied exerts pressure on the deformable membrane 30-2. The isostatic pressure of the fluid 9-2 then deforms the deformable membrane 30-2 by pushing it against the first part 10 and the second part 11. The deformation of the deformable membrane 30-2 following the application of the fluid 9- 2 generates a reduction in the volume of the first chamber 2-2. In particular, the shape of the internal face 30g of the deformable membrane 30-2 is modified, after introduction of the pressurizing fluid 9-2 in the second chamber 3-2, so as to take in part the same shape as the assembly formed by the parts 10.11.

The fluid 9-2 thus applies mechanical pressure to the parts 10, 11 through the deformable membrane 30-2. More specifically, the fluid 9-2 imposes a hydrostatic pressure on the parts 10, 11 and on the adhesive layer 31 assembled, and in particular a pressure on the entire adhesive layer 31. In other words, the fluid 9- 2 by means of the deformable membrane 9-2 applies pressure to the entire surface over which the layer of adhesive 31 extends.

In particular, the extra thicknesses 70-4, 70-5 of the membrane 30-2 advantageously bear respectively against the corners 50-3, 50-4 formed by the assembly of the parts 10.11. The deformable membrane 30-2 thus exerts a force on all of the zones of the assembly of the parts 10, 11. This gives optimum bonding to the whole of the assembly formed by the parts 10, 11, in particular in the corner areas 50-3, 50-4. The bonding of the assembly thus obtained has optimal mechanical strength, this bonding being produced in a homogeneous manner.

In known manner, the adhesive power of the adhesive layer 31 can be increased by heating due to the crosslinking of the adhesive.

In this case, the device 100-2 may include a heating member 40 consisting, for example, of a plurality of heating resistors. The heating element 40 can, for example, be present in the support 33 as illustrated. When a heating step is carried out, this can be carried out while the parts 10, 11 are subjected to the pressure applied by the fluid 9-2. In variants not illustrated, the heating member may be present in the second chamber 3-2 and / or in the deformable membrane 30-2 and / or on the deformable membrane 30-2 and / or in the first chamber 2- 2. In another variant, the device 100-2 does not include a heating member and the heating of the adhesive layer 31 is carried out by a heating member external to the device 100-2.

Claims (11)

1. Device (100-1; 100-2) for applying mechanical pressure to at least one part (1; 10, 11), the device (100-1; 100-2) comprising - a first chamber (2-1; 2-2) intended to contain said at least one part (1; 10,11), - a second chamber (3-1; 3-2) intended to contain a pressurizing fluid (9-1; 9-2), - a deformable membrane (30-1; 30-2) separating the first chamber (2-1; 2-2) from the second chamber (3-1; 3-2), - injection means (5-1; 5-2) of the fluid (9-1; 9-2) in the second chamber (3-1; 3-2), the deformable membrane (30-1; 30- 2) comprising at least a first portion (30b; 30h), a second portion (30c; 30i) and a transition zone (30e; 30k) defining a corner (60-1; 60-3) between the first portion (30b ; 30h) and the second portion (30c; 30i), this device (100-1; 100-2) being characterized in that the membrane comprises an additional thickness (70-1; 70-4) present on the corner (60- 1; 603) of the transition zone (30e; 30k). 2. Device (100-1; 100-2) according to claim 1, in which the additional thickness (70-1; 70-4) is formed by an element attached to the deformable membrane (30-1; 30-2). 3. Device (100-1; 100-2) according to claim 1, wherein the allowance (70-1; 70-4) is formed in a monolithic manner with the deformable membrane (30-1; 30-2). 4. Device (100-1; 100-2) according to any one of claims 1 to 3, wherein the deformable membrane (301; 30-2) is impermeable. 5. Device (100-1; 100-2) according to any one of claims 1 to 4, wherein the fluid (9-1; 9-2) pressurizing is an incompressible fluid. 6. Device (100-1) according to any one of claims 1 to 5, in which the first chamber (2-1) is delimited by a support (6) on which said at least one part (1) is intended to be positioned and in which the deformable membrane (301) is located around the first chamber (2-1). 7. A method of impregnating a piece forming a fibrous texture (1) with an impregnating composition (8) using a device according to any one of claims 1 to 6, the fibrous texture (1) having at least a first part (la), a second part (lb) and an intermediate zone (ld) defining a corner (50-1) between the first part (la) and the second part (lb), and the method comprising the following steps : positioning of the fibrous texture (1) in the first chamber (2-1), the fibrous texture (1) being present opposite the deformable membrane (30-1), - introduction of an impregnation composition (8) into the first chamber (2-1) between the fibrous texture (1) and the deformable membrane (30-1), - Introduction of a pressurizing fluid (9-1) into the second chamber (3-1) in order to apply via said membrane a pressure on the fibrous texture (1) so as to impregnate it with the composition d 'impregnation (8), the excess thickness (70-1) of the deformable membrane (30-1) being supported on the corner (50-1) of the fibrous texture (1) during the application of pressure. 8. Impregnation method according to claim 7, in which the fibrous texture (1) constitutes a fibrous preform intended to form a fibrous reinforcement of an aeronautical engine casing, said fibrous texture (1) being maintained in shape on a support. (6) so as to define a central ferrule (la) extending in width in an axial direction between a first annular flange (lb) and a second annular flange (le), the first flange (lb) and the second flange ( le) extending in a radial direction towards the outside of the central ferrule (la), a first intermediate zone (ld) defining a first corner (50-1) between the first flange (lb) and the central ferrule (la ), a second intermediate zone (le) defining a second corner (50-2) between the second flange (le) and the central ferrule (la), the deformable membrane (30-1) being located around the first chamber (2 -1), the membrane further comprising a first annular central portion (30b) extending selo n an axial direction between a second annular portion (30c) and a third annular portion (30d), the second portion (30c) and the third portion (30d) extending in a radial direction towards the outside of the first portion ( 30b), a first transition zone (30e) comprising an additional thickness (70-1) and defining a corner (601) between the first portion (30b) and the second portion (30c), a second transition zone (30f) comprising an extra thickness (70-2) and defining a corner (60-2) between the first portion (30b) and the third portion (30d), so that the extra thickness (70-1) of the first transition zone ( 30e) and the extra thickness (70-2) of the second transition zone (30f) respectively come to bear on the first corner (501) and the second corner (50-2) of the fibrous texture (1) during the application of pressure. 9. A method of bonding between at least two parts (10, 11) using a device according to any one of claims 1 to 6, the method comprising the following steps: - assembly of at least a first part (10) on a second part (11), at least one layer of adhesive (31) being present between the two parts (10, 11) assembled, - placement of the parts (10, 11) in the first chamber (22), the deformable membrane being opposite the parts (10, 11) assembled, the assembly of said at least first part (10) on the second part (11 ) forming at least one 5 corner (50-3) adjacent to the first part (10) and to the second part (11), said at least one corner (50-3) being defined by the superposition of these parts (10,11), - introduction of a pressurizing fluid (9-2) into the second chamber (3-2) in order to impose via said membrane 10 pressing the assembled parts (10, 11) allowing them to be bonded via the adhesive layer (31), the excess thickness (70-4) of the deformable membrane (30-2) coming to bear on the corner (50-3) defined by the first part (10) and the second part (11) when applying 15 pressure. 1/6 CM ι Ο ΙΟ /////// f ///////// CM) your \ \ \ \\ \\ \\ \\ \ >>>>>>>>>>>>>>>>>>>>> ->> X LO