Classifications

• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D25/00—Woven fabrics not otherwise provided for
  • D03D25/005—Three-dimensional woven fabrics
• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D49/00—Details or constructional features not specially adapted for looms of a particular type
  • D03D49/04—Control of the tension in warp or cloth
  • D03D49/20—Take-up motions; Cloth beams
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2505/00—Industrial
  • D10B2505/02—Reinforcing materials; Prepregs

Definitions

• the invention relates to the manufacture of a fabric, in particular a three-dimensional fabric, in shape, that is to say having a variable thickness over its width.
• a fabric can in particular serve as reinforcement or preform in the manufacture of composite objects by resin transfer molding, particularly for applications in aeronautics.
• the reinforcement does not always have a constant thickness over its entire width.
• the surface of the mold on which the reinforcement is placed before the injection of the resin may not be developable.
• the fabric may be advantageous for the fabric to have a variable thickness, for example, a lower thickness on its edges than in its center.
• Such a fabric can be manufactured using a Jacquard type loom, which is described in particular in document FR 3 074 195 A1.
• Figure 1 illustrates a Jacquard type loom 10 used for the production of a three-dimensional fabric obtained by multilayer weaving between a plurality of layers of warp threads 30 and a plurality of layers of weft threads 31.
• the weaving loom 10 is equipped with a Jacquard mechanism 11 supported by a superstructure not shown in Figure 1.
• the loom 10 also includes a harness 20 consisting of a cutting board 21 and control wires or heddles 22, each heddle 22 being connected at one end to a control hook 12 of the Jacquard mechanism 11 and at the other end to one of the return springs 13 fixed to the frame 14 of the loom 10.
• Each heddle 22 comprises an eyelet 23 crossed by a warp wire 30.
• the heddles 22 and their associated eyelet 23 are animated by a substantially vertical oscillation movement represented by the double arrow F under the tensile forces exerted respectively by the hooks control 12 and return springs 13.
• the heddles 22 make it possible to lift certain warp threads 30 and thus create a shed 15, that is to say an opening between lower and upper layers of warp threads 30 allowing the introduction of weft threads 31 by means of 'a lance 40.
• the lance 40 is provided at its end with a clamp 41 which grasps a weft thread 31 from a spool 50 to place it through the opening between the layers of threads of warp 30 created by the shed 15, the weft thread 31 being cut using a knife 60 after its positioning in the shed 15.
• the lance 40 is then ready to again grab a new weft thread 31 from the spool 50 and place it either again in the shed 15, or in a different shed depending on the defined weaving.
• the reinforcement can form localized bumps, which can give rise to pinching of the fabric when closing the mold, resulting, in the final object, in areas whose mechanical properties are not controlled.
• An aim of the invention is therefore to design a loom making it possible to control the expansion of the shaped fabric and thus improve the RTM process which may be implemented subsequently.
• the invention proposes a Jacquard type loom for the manufacture of a fabric, in particular a two-dimensional or three-dimensional fabric, having a variable thickness over its width by weaving between a plurality of warp threads and a plurality of weft threads, said loom comprising: - a plurality of control wires, connected to a mechanism capable of moving the control wires in a vertical direction between a reference position and a first opening position of the chain wires, each control wire being further provided with an eyelet crossed by one of the warp threads,
• a fabric holding device arranged downstream of the plurality of control wires and the lance, comprising at least two support surfaces, including at least a first support surface and a second support surface arranged on either side and on the other side of the fabric to compress the fabric between said support surfaces.
• Said loom is characterized in that at least the first support surface is shaped in a manner that is at least partially complementary to a surface of the fabric.
• At least one surface of the fabric is non-flat.
• the first support surface has a non-planar shape whose concavity is oriented towards the surface of the fabric.
• the support surface matches at least partly the non-flat surface of the fabric, that is to say, when the first support surface is brought towards the surface of the fabric following the vertical direction , the distance between the first support surface and the surface of the fabric is substantially constant at least in part of the width of the fabric.
• upstream and downstream are understood in the sense of the progress of the weaving of the threads.
• the holding device comprises at least one holding bar having said at least one first support surface.
• said support bar comprises a body and a removable portion carrying the first support surface, the removable portion being reversibly linked to the body of the support bar.
• Said removable portion may be in the form of a solid metal bar, in which the first bearing surface is formed.
• the holding device comprises a table presenting the second support surface, said second support surface being flat.
• the object presents a form of revolution.
• FIG. 1 shows an overview of a known Jacquard type loom
• FIG. 3 is a sectional view of the three-dimensional fabric of Figure 2A and of a bar of the holding device according to one embodiment
• FIG. 4 is a sectional view of the three-dimensional fabric of Figure 2A and of a bar of the holding device according to the state of the art;
• FIG. 5 shows an overview of a Jacquard type loom according to one embodiment of the invention
• FIG. 6 is a principle graph of the evolution of the expansion as a function of the distance between the bearing surfaces of the holding device.
• the drawings have not necessarily been represented to scale.
• the invention relates to the manufacture of a shaped fabric having controlled expansion.
• reference will mainly be made to a three-dimensional fabric, but the description also applies to a two-dimensional fabric.
• Figure 2A illustrates an example of a shaped three-dimensional fabric, seen in section.
• the fabric has a flat lower surface and a thickness increasing successively from its edge (thickness ei) towards its center (thickness es) with an intermediate thickness e2, thus forming a non-flat upper surface.
• this thickness variation profile is given for illustrative purposes only and is not limiting.
• Figure 2B illustrates a second example of a shaped three-dimensional fabric, seen in section.
• shaped weaving consists of weaving a profile proportional to the interior profile of the composite object to be produced.
• this profile is obtained by a differential draw of wires by means of a non-cylindrical take-up roller which allows different lengths of wires depending on the location of each wire on the roller.
• the expansion of such a fabric can be defined as being the ratio between the total volume occupied by the fabric, as produced by the loom, and a reference volume for this fabric, corresponding for example to the smallest volume at which we could bring this tissue by compressing it.
• the expansion is controlled by the use of a holding device which has a support surface shaped at least partially complementary to the shape of the surface of the fabric opposite.
• Figure 3 illustrates a sectional view of the fabric of Figure 2A and of a bar 92 of the holding device according to one embodiment of the invention.
• the support surface 93 which comes into contact with the fabric T, makes it possible to compress the assembly of the warp and weft threads and thus reduce the expansion of the fabric.
• the surface of the jaw 82 facing the tissue is flat and cannot therefore come into contact with the entire surface of the tissue nor compress evenly the fabric.
• the lance 40 is provided at its end with a clamp 41 which grasps a weft thread 31 from a spool 50 to place it through the opening between the layers of warp threads 30 created by the shed 15, the weft thread 31 being cut using a knife 60 after its positioning in the shed 15.
• the shape of the support surface could not coincide perfectly with the shape of the surface of the fabric, but present an intermediate shape between a planar shape and the shape of the surface of the fabric, this shape intermediate having a concavity oriented towards the surface of the fabric (in other words, if the surface of the fabric has a hollow, the corresponding part of the support surface has a bump and vice versa, if the surface of the fabric has a bump, the corresponding part of the support surface has a hollow).
• the relative distance difference between the support surface and the surface of the fabric depending on the width of the fabric is on average less than 30%, or even less than 10%.
• the support surface 94 facing the lower surface of the fabric which is flat, belongs to a table 91 secured to the frame 14.
• the table 91 can be replaced by one or more holding bar(s) also having a supporting surface complementary to the lower surface of the fabric, and arranged opposite the support surface 93 of the holding bar 92 in a direction Z perpendicular to the main surface of the fabric.
• the support surface 93 is therefore specifically shaped to at least partially match the shape of the non-flat surface of the fabric.
• the holding bars can be in the form of an assembly of a body secured to the frame of the loom and a removable portion carrying the support surface.
• the removable portion can for example be linked to the body by screws or any reversible connection means.
• the distance d between the support surfaces 93 and 94 is chosen so as to apply the support surface against the surface of the fabric and to exert a force of compression of the fabric between the holding bar 92 and the table 91 , or, where applicable, between the two retaining bars.
• the distance d between the support surfaces is generally fixed during weaving, the holding bar 92 and the table 91 being fixed relative to the frame. However, this distance can possibly be adjusted, particularly when fine-tuning the weave, for example using shims of different thicknesses.
• Figure 6 thus schematically illustrates the expansion F for a fabric of the type of that of Figure 2A, obtained empirically as a function of the distance d between the bearing surface of the holding bar and the bearing surface of the table.
• a limit which may be non-zero
• Those skilled in the art are therefore able, using simple tests, to determine the distance between the support surfaces to obtain a determined expansion (preferably minimal) for a given fabric.
• the holding bar 92 is then fixed at the desired distance from the table 91.
• the thickness of the fabric leaving the loom 10 is substantially equal to the thickness for which the mold was designed.
• the quality of the composite object is significantly improved compared to that of an object made from a fabric whose expansion has not been controlled during weaving.
• the absence of folds or bumps during placement in the impression makes it possible to preserve the structure of the tissue at any point of the object, and thus avoid changes in localized mechanical properties.
• the invention finds application for the manufacture of any type of casing or casing element having a shape of revolution, in particular for an aeronautical engine, such as a fan casing, a turbine casing, a nozzle casing or a mixer housing.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Looms (AREA)
• Woven Fabrics (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=83996399

Family Applications (1)

Country Status (4)

Family Cites Families (6)

• 2022
  • 2022-08-22 FR FR2208431A patent/FR3138920B1/fr active Active
• 2023
  • 2023-08-22 EP EP23772296.2A patent/EP4577691A1/de active Pending
  • 2023-08-22 CN CN202380066606.2A patent/CN119948216A/zh active Pending
  • 2023-08-22 WO PCT/FR2023/051285 patent/WO2024042294A1/fr not_active Ceased

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