Weaving process with selvedge

Abstract

Selvedge Weaving Method The invention relates to a three-dimensional weaving method for a texture (200) between a plurality of warp yarns (201, 203) extending along a longitudinal direction (DL) and a plurality of weft yarn columns (202), said weft yarns (202) extending along a transverse direction (DT), the texture (200) comprising a central portion (210) extending along the transverse direction (DT) between a first selvedge (221) and a second selvedge (222), the method being characterized in that at least one of the selvedges (221, 222) comprises at least one primary weave plane perpendicular to the transverse direction (DT) in which the weft yarns (202) from the same weft yarn column (202) of the central portion (210) of the texture (200) are linked by grouping, the weft yarns (202) of the same grouping being aligned along the longitudinal direction (DL). Figure for the abbreviation: Fig. 1

Description

Title of the invention: Weaving method with selvedge Technical field

[0001] The present invention relates to the weaving of woven textures using a Jacquard type loom, and in particular to the weaving of woven textures having significant thicknesses. Prior art

[0002] A Jacquard type loom is conventionally used for producing textures by three-dimensional weaving between a plurality of layers of warp threads and a plurality of layers of weft threads. Such a loom is described in particular in document FR 3 074 195 A1.

[0003] In a known manner, the loom is equipped with a Jacquard mechanism. The loom also comprises a harness comprising control or heddle threads, each control thread being connected at one end to a control element of the Jacquard mechanism.

[0004] Each control thread comprises an eyelet through which a warp thread passes. The control threads and their associated eyelet are capable of moving vertically. The control threads make it possible to lift certain warp threads and thus create a shed, i.e. an opening between lower and upper layers of warp threads. Said shed thus opened allows the introduction of a weft thread by means of a lance. The lance comprises a rod which can be provided at its end with a clamp which grips a weft thread from a bobbin to place it through the opening between the layers of warp threads created by the shed, the weft thread being cut using a cutting tool after its positioning in the shed. The loom also comprises a comb whose striking makes it possible to pack the weft thread inserted in the shed.

[0005] However, it has been found that the inserted weft threads were not properly blocked by the warp threads at the edges of the texture during weaving. However, if the weft threads are not properly blocked during their insertion, the following weft threads may not be placed in the correct location and may therefore not interact correctly with the rapier, the cutting tooling and any yarn guidance systems. For example, a misplaced weft thread may not be caught by the rapier. Thus, weaving must be interrupted frequently to correct anomalies. Disclosure of the invention

[0006] In order to ensure blocking of the inserted weft threads, it has been proposed to use selvedge warp threads on the edges of the texture to block the weft threads inserted during weaving.

[0007] However, in order to ensure satisfactory blocking of the weft yarns by the selvedge warp yarns, the binding between the weft yarns and the selvedge warp yarns was very dense. This thus generated selvedge areas with a much higher yarn density than the central part of the texture, which could cause unwanted ripples or distortions of the selvedge areas or lead to jamming effects when striking the reed. In addition, this gradually generated misalignment during weaving on the loom between the selvedge areas and the central part of the texture, the denser selvedge areas not advancing as quickly on the loom as the less densely yarn-filled central part.

[0008] The more layers of yarns the fiber texture had, the greater the problems of placement of the weft yarns and the difference in density between the selvedge areas and the central part of the texture.

[0009] The present invention aims to remedy the aforementioned drawbacks by proposing a textured edge suitable for three-dimensional weaving.To this end, the invention proposes a method for three-dimensional weaving of a texture between a plurality of warp threads extending in a longitudinal direction and a plurality of columns of weft threads, said weft threads extending in a transverse direction, the texture extending in the transverse direction between a first selvedge and a second selvedge, the texture comprising a central portion present between the selvedges, the method being characterized in that at least one of the first or second selvedge comprises at least one primary weaving plane perpendicular to the transverse direction in which the weft threads from the same column of weft threads of the central portion of the texture are linked by grouping, the weft threads of the same grouping being aligned in the longitudinal direction.

[0010] Such a weaving method makes it possible to ensure, thanks to the selvedge(s), suitable blocking of the inserted weft threads, thus reducing the risks of poor alignment of the weft threads to be inserted and consequently reducing anomalies and interruptions in weaving.

[0011] By binding the weft threads in groups rather than individually in the selvedge(s) of the texture, the density of threads in said selvedge(s) is also reduced. This limits the phenomena of undulation of the selvedge(s), the risks of jamming when striking the reed and the progressive misalignment between the selvedge(s) and the central part of the texture during weaving. In addition, the alignment of the weft threads of the same group in the longitudinal direction makes it possible to further reduce the misalignment between the selvedge(s) and the central part of the texture during weaving on the loom.

[0012] This method also makes it possible to do away with the use of templets, i.e. of conical rollers comprising pins configured to grip the selvedge threads, allowing by their rotation to force the alignment of the selvedge with the central part during weaving. Indeed, the templets can damage the selvedge threads with their pins, and only grip the surface threads which can cause a shift between the surface threads of the selvedge pulled by the templets and the core threads which are not stressed by said templets.

[0013] According to a particular embodiment of the invention, the groupings of weft threads in the primary weaving plane bring together a number of weft threads of between two and seven, and preferably between two and five.

[0014] According to a particular embodiment of the invention, the primary weaving plan comprises at least one portion in which the number of warp threads in the first or second selvedge binding the weft threads from the same column of weft threads of the central part of the texture is half the number of weft threads of said column, i.e. less than the number of layers of weft threads.

[0015] Thus, the selvedge(s) comprise a reduced number of warp threads, which makes it possible to have a limited thread density.

[0016] According to another particular embodiment of the invention, the warp threads of at least the first or second selvedge bind the weft threads according to a satin or plain type weaving pattern in the primary weaving plane.

[0017] Satin or plain weave armors allow very strong binding of the weft threads, said weft threads thus being blocked in a very satisfactory manner during weaving of the texture.

[0018] The warp threads of at least the first or second selvedge may also bind the weft threads in a twill-type weave pattern in the primary weaving plane.

[0019] The choice of weaving weave may depend on the number of weft threads in the grouping, the count of the weft threads and the weft thread density. Thus, the higher the weft thread density, the more we will prefer a weaving weave requiring a low warp thread density, i.e. a weaving weave with a low warp binding frequency by integrating warp floats.

[0020] When the warp threads of at least the first or second selvedge bind the weft threads in a satin or plain weave pattern in the primary weaving plane, there are two possible embodiments. According to a first embodiment, the weft threads are bound so as to form a superposition of plies each having a two-dimensional satin or plain weave in the primary weaving plane, the different plies not being bound to each other in the primary weaving plane. According to another embodiment, the weft threads are bound so as to form a superposition of plies each having a bidi weave satin or canvas type dimensional in the primary weaving plane, the different layers being linked to each other by a local bond in the primary weaving plane.

[0021] According to another particular embodiment of the invention, the warp threads of at least the first or second selvedge bind the weft threads according to a three-dimensional weaving pattern in the primary weaving plane. For example, the warp threads of at least the first or second selvedge may bind the weft threads according to an interlock type weaving pattern in the primary weaving plane. Different three-dimensional weaving modes are described in document WO 2006 / 136755.

[0022] The use of a three-dimensional weaving pattern makes it possible to further reduce the yarn density required to lock the weft yarns.

[0023] According to a particular embodiment of the invention, at least the first or second selvedge further comprises at least one secondary weaving plane perpendicular to the transverse direction in which the warp threads are arranged on either side of sets of weft threads comprising weft threads originating from one or more of the same columns of weft threads of the central part of the texture.

[0024] The use of one or more secondary weaving planes complements the primary weaving plane(s). Indeed, the primary weaving planes allow satisfactory blocking of the weft threads in the transverse direction, but the groups of weft threads may not be correctly blocked relative to each other in the thickness direction of the texture perpendicular to the longitudinal and transverse directions. The use of such secondary weaving planes thus makes it possible to block the different groups of weft threads in the thickness direction.

[0025] According to a particular embodiment of the invention, the number of warp threads in the secondary weaving plane is two.

[0026] Thus, the density of warp threads in a secondary weaving plane is low, and makes it possible to reduce the overall density of threads in the selvedge.

[0027] According to a particular embodiment of the invention, the weaving plane(s) of the first or second selvedge closest to the texture are secondary weaving planes.

[0028] Thus, the wefts inserted into the thickness of the fibrous texture are better contained, which makes it possible to avoid distortions within the central part of the texture.

[0029] According to a particular embodiment of the invention, the weaving plane(s) of the first or second selvedge furthest from the texture are secondary weaving planes.

[0030] Thus, the end of the selvedge is well maintained and compacted, and does not risk separating in the thickness direction.

[0031] According to a particular embodiment of the invention, the first or second selvedge does not comprise more than four consecutive primary weaving planes in the transverse direction.

[0032] According to a particular embodiment of the invention in which the central part of the texture has a reduction in the number of weft threads per column of weft threads in the longitudinal direction, the number of warp threads in the weaving planes of the first or second selvedge remains constant in the longitudinal direction.

[0033] By maintaining a constant number of warp threads along the longitudinal direction in the weaving planes of the selvedge, i.e. by not producing any exit of selvedge warp threads, the presence of free and unbound selvedge warp threads which would therefore be liable to break and cause interruptions in the weaving is avoided. Thus, all the warp threads used in the selvedge are well attached and unlikely to create anomalies or defects in the weaving of the selvedge.

[0034] According to a particular embodiment of the invention, the texture is intended to form a fibrous reinforcement of a composite material part of an aeronautical engine.

[0035] The invention further provides a method for manufacturing a part made of composite material comprising:

[0036] - weaving a texture by implementing the weaving method described above cededly,

[0037] - shaping the woven texture obtained to obtain a preform of the part to manufacture,

[0038] - densification of the preform by a matrix so as to obtain the part in composite material whose reinforcement is formed by the preform. Brief description of the drawings

[0039] [Fig-1] [Fig. 1] is a schematic perspective view of a Jacquard type loom for producing a woven texture.

[0040] [Fig.2] [Fig.2] illustrates a weaving plan belonging to the central part of the woven texture of [Fig.l].

[0041] [Fig.3] [Fig.3] illustrates a primary weave plane belonging to a selvage of the woven texture of [Fig.l].

[0042] [Fig.4] [Fig.4] illustrates a secondary weaving plane belonging to a selvedge of of the woven texture of [Fig.l].

[0043] [Fig.5] [Fig.5] illustrates a weaving plane belonging to the central part of a woven texture comprising a reduction in the number of weft threads along the longitudinal direction.

[0044] [Fig.6] [Fig.6] illustrates a primary weaving plan belonging to a selvedge of the woven texture of [Fig.5]. Description of the embodiments

[0045] The invention applies generally to three-dimensional weaving methods for producing woven textures between layers of warp threads and layers of weft threads. By "three-dimensional weaving" is meant here a weaving method by which at least some of the warp threads bind weft threads over several weft layers. It is considered that a woven texture produced by three-dimensional weaving may comprise another type of weaving on its surface, for example two-dimensional weaving, in order to improve its surface condition. Furthermore, it is considered that a woven texture produced by three-dimensional weaving may comprise another type of weaving at its selvedges, in order to ensure the blocking of the weft threads at the edge of the texture.

[0046] The woven texture may, for example, have a three-dimensional weave of the interlock, multi-serge or multi-satin type. Different three-dimensional weaving methods that can be used to form the woven texture are described in document WO 2006 / 136755.

[0047] [Fig. 1] illustrates a loom 100 for carrying out the weaving method of the invention. The loom 100 according to the invention makes it possible to obtain a woven texture 200 by weaving a plurality of layers of warp threads 201 and 203 with a plurality of layers of weft threads 202. The warp threads 201 and 203 extend in a longitudinal direction DL and the weft threads 202 extend in a transverse direction DT, the transverse direction DT being perpendicular to the longitudinal direction DL.

[0048] The woven texture 200 thus extends in length along the longitudinal direction DL, in width along the transverse direction DT and in thickness along a thickness direction DE perpendicular to the longitudinal and transverse directions DT and DL.

[0049] The loom is equipped with a Jacquard mechanism 110 supported by a superstructure not shown in [Fig.l]. The loom 100 also comprises a harness 120 comprising control or heddle threads 121, each control thread 121 being connected at one end to a control element 111 of the Jacquard mechanism 110. In the example illustrated in [Fig.l], each control thread 121 is connected at one end to a control hook 111 of the Jacquard mechanism 110 and at the other end to a return spring 112 fixed to the frame 113 of the loom 100. The control threads 121 extend in the thickness direction DE. The harness 120 may also comprise a tying board 122.

[0050] Each control thread 121 comprises an eyelet 121a crossed by a warp thread 201, 203. Each warp thread 201 or 203 of the loom 100 passes through an eyelet 121a of the harness 120. The warp threads 201 or 203 are organized at the level of the harness 120 of the loom 100 into a plurality of horizontal layers and vertical columns which are manipulated by the loom 100 to allow the insertion of weft threads 202 according to the weaving pattern(s) programmed in the loom 100. The weft threads 202 are inserted between the warp threads 201 or 203 by column extending in the thickness direction DE. In order to allow the introduction of each column of weft threads 202 during the weaving of the texture 200, a system for taking up the warp threads 201, 203 (not shown in [Fig.l]) is associated with the loom 100. This system, placed downstream of the loom 100, has the role of holding all the warp threads 201, 203 together in a clamping device and of allowing the advancement of the warp threads 102, 203 by a determined distance in the longitudinal direction DL after the insertion of each weft column 202.

[0051] The terms “upstream” and “downstream” are defined here according to the direction of advance of the warp threads 201, 203 in the loom 100, that is to say according to the weaving direction, along the longitudinal direction DL.

[0052] The control threads 121 and their associated eyelet 121a are able to move along the thickness direction DE. In [Fig.l], all the control threads 121 are in a neutral position in which no traction is exerted by the Jacquard mechanism 110. In this configuration, no weft thread 202 is inserted and all the warp threads 201 extend parallel to the longitudinal direction DL.

[0053] When inserting a weft thread 202, a portion of the control threads 121 are subjected to tensile forces exerted by the control hooks 111. In this configuration, the control threads make it possible to raise or lower warp threads, so as to separate an upper layer of warp threads from a lower layer of warp threads by an opening, called a shed.

[0054] The loom 100 also comprises a lance 130, present downstream of the control threads 121. The lance 130 is composed of a rod 131, a first end of which is connected to an actuation system (not shown in [Fig.l]) making it possible to drive the rod 131 with a back-and-forth movement in the transverse direction DT. The path of the lance 130 can be fixed relative to the frame 113 of the loom 100. The other end of the rod 131 is provided with a clamp 132 which, after having passed through the shed during the outward path of the rod 131, can come to grip a weft thread 202 stored on a bobbin 140 to unwind it in the shed during the return path of the rod 131. The weft thread 202 thus placed inside the shed is then cut in the vicinity of the bobbin 140 by a cutting tool 150 and released at its other end by the clamp 132.A comb 160 present upstream of the lance 130 and downstream of the harness 120 in its rest position is then folded down in order to pack the weft thread(s) 202 introduced into the shed.

[0055] The loom 100 may further comprise a guide device comprising at least one upper jaw and one lower jaw configured to be positioned in contact with the woven texture 200 and on either side of said texture 200 along the thickness direction DE, said guide device being present downstream of the plurality of control threads 121 and the lance 130, the guide device being able to move along the thickness direction DE so as to move the woven texture 200 upwards or downwards. Such a guide device makes it possible to adjust the position along the thickness direction DE of the woven texture 200, so as to facilitate the insertion of the weft threads 202.

[0056] The weaving method according to the invention makes it possible to produce the woven texture 200 extending in the transverse direction DT between a first selvedge 221 and a second selvedge 222. The first selvedge 221 and the second selvedge 222 extend in the longitudinal direction DL along the woven texture 200. Preferably, the first selvedge 221 and the second selvedge 222 extend in the longitudinal direction Dl over the entire length of the woven texture 200. The woven texture 200 comprises a central portion 210 which extends between the first selvedge 221 and the second selvedge 222. Preferably, the central portion 210 of the woven texture 200 extends from the first selvedge 221 to the second selvedge 222.

[0057] The guiding device as described above makes it possible to adjust the positioning of the central portion 210 of the texture 200 along the thickness direction D during the insertion of the weft threads 202. The guiding device as described above can also make it possible to adjust the positioning of the selvedges 221 and 222 along the thickness direction DE during the insertion of the weft threads 202. The guiding device preferably makes it possible to adjust the position of the selvedge(s) 221 and 222 along the thickness direction DE independently of the adjustment of the position of the central portion 210 along the thickness direction DE. Thus, the selvedge(s) 221 and 222 can be held by upper and lower jaws of the guiding device distinct from the upper and lower jaws of the guiding device holding the central portion 210.

[0058] Correct positioning of the woven texture 200 along the thickness direction DE, i.e. correct positioning of both the central portion 210 and the selvedge(s) 211 and 222 along the thickness direction DE, is particularly important when the central portion 210 of the fibrous texture has portions in which the number of weft threads per column of weft threads is greater than or equal to 6, in order to ensure correct insertion of the weft threads by the rapier 130.

[0059] The central portion 210 of the woven texture 200 is produced by three-dimensional weaving between a plurality of central warp threads 201 and the plurality of weft threads 202.

[0060] [Fig.2] illustrates a portion of an example of a weaving plane of the central portion 210 of the woven texture 200 perpendicular to the transverse direction DT. In par In particular, [Fig.2] illustrates four columns N, N+1, N+2 and N+3 of weft threads 202 of said example of weaving plan of the central part 210.

[0061] In the example illustrated in [Fig.2], each column N, N+1, N+2 and N+3 of weft threads 202 of the central part 210 comprises twelve weft threads 202. It is of course not beyond the scope of the invention if one or more columns of weft threads of the central part comprise more than twelve weft threads. It is also not beyond the scope of the invention if one or more columns of weft threads of the central part comprise more than twelve weft threads.

[0062] The columns N, N+1, N+2 and N+3 of weft yarns 202 in the central portion 210 of the woven texture 200 are woven three-dimensionally with the plurality of central warp yarns 201. In the example illustrated in [Fig. 2], the central warp yarns 201 are woven with the weft yarns 202 in a multi-twill weave in the central portion 210. It is of course not outside the scope of the invention if the central warp yarns 201 are woven with the weft yarns 202 in another three-dimensional weaving weave in the central portion 210.

[0063] The first and second selvedges 221 and 222 are made by weaving between a plurality of selvedge warp yarns 203 and the plurality of weft yarns 202. The weft yarns 202 in the first or second selvedge 221 or 222 are woven with the plurality of selvedge warp yarns 203. The selvedge warp yarns 203 are linked with the weft yarns 202 in the selvedges 221 or 222 according to successive weaving planes perpendicular to the transverse direction DT.

[0064] Preferably, the warp threads 203 present in the selvedge(s) 221 or 222 have a smaller diameter than the diameter of the warp threads 201 present in the central part 210 of the texture 200, in order to better block the weft threads 202 in the selvedge(s) 221 and 222. Preferably, the warp threads 203 present in the selvedge(s) 221 or 222 have an average diameter between 6 times and 10 times smaller than the average diameter of the warp threads 201 of the central part 210.

[0065] The warp threads 203 present in the selvedge(s) 221 or 222 may be made of a material different from the warp threads 201 of the central part 210. For example, the warp threads 203 present in the selvedge(s) 221 or 222 may be made of polyester, for example with a count of 220 tex.

[0066] At least a portion of the weaving planes according to which the selvedge warp yarns 203 and the weft yarns 202 are woven into the first or second selvedge 121 or 122 are primary weaving planes. The primary weaving planes are weaving planes in which the weft yarns 202 from the same column of weft yarns 202 of the central portion 210 are linked by grouping by the selvedge warp yarns 203, the weft yarns 202 of the same grouping being aligned along the longitudinal direction DL.

[0067] In the example illustrated in Figures 3 and 4, the weft threads 202 from the same column of weft threads 202 of the central part 210 are linked in pairs by the selvedge warp threads 203, the weft threads 202 of the same pair being aligned in the longitudinal direction DL. Groups comprising only two weft threads 202 are thus produced. It is of course not outside the scope of the invention if the groupings comprise more than two weft threads. For example, the weft threads from the same column of weft threads of the central part can be linked in trios by the selvedge warp threads 203, the weft threads of the same trio being aligned in the longitudinal direction DL.

[0068] The groupings may comprise only two to seven weft threads, or even only two to five weft threads. Preferably, the groupings within a primary weaving plane gather the same number of weft threads. Preferably, the groupings within a secondary weaving plane gather the same number of weft threads.

[0069] A group of weft threads according to the invention brings together at least two weft threads. By "linked by grouping", it is meant that all the weft threads 202 not present on the surface coming from the same column of weft threads 202 of the central part 210 are linked by grouping. The weft threads 202 present on the surface of the selvedge 221 or 222 can be linked alone, or in a smaller number. Thus, preferably, in a primary weaving plane, there are at most two weft threads 202 for each set of weft threads 202 coming from the same column of weft threads 202 which are not linked by grouping.

[0070] A single selvedge 221 or 222 may comprise a single primary weaving plane, or may comprise several primary weaving planes. Preferably, a single selvedge 221 or 222 comprises at least two primary weaving planes, in order to ensure satisfactory blocking of the weft threads. A single selvedge 221 or 222 may comprise different primary weaving planes, that is to say that the weft threads 202 coming from a single column of weft threads 202 of the central part 210 are linked according to different groupings from one primary weaving plane to another.

[0071] Preferably, in a primary weaving plane, the selvedge warp threads 203 bind the weft threads 202 in a satin or plain weave pattern. Indeed, satin or plain weave patterns allow for strong binding of the weft threads 202, which ensures their blocking at the selvedge 221 or 222. Preferably, if the weft threads 202 have a large diameter, for example a diameter greater than or equal to 2 mm, the selvedge warp threads 203 will bind the weft threads 202 in the primary weaving plane(s) in a satin weave pattern. On the contrary, if the weft threads 202 have a small diameter, for example a diameter less than 2 mm, the selvedge warp threads 203 will preferably bind the weft threads 202 in the primary weaving plane(s) in a plain weave. Generally, if the density of weft threads 202 in the central portion 210 of the texture 200 is high, i.e. if the density is greater than 4 threads per cm in each weaving plane, the selvedge warp threads 203 will bind the weft threads 202 in the primary weaving plane(s) in a satin weave. On the contrary, if the density of weft threads 202 in the central portion 210 of the texture 200 is low, i.e. if the density is less than or equal to 4 threads per cm in each weaving plane, the selvedge warp threads 203 will bind the weft threads 202 in the primary weaving plane(s) in a plain weave.More generally, the choice of weaving pattern takes into account the density of weft threads, the count of the weft threads and the number of weft threads to be blocked.

[0072] [Fig. 3] illustrates a portion of an exemplary primary weaving plane of the first or second selvedge 221 or 222 of the woven texture 200 perpendicular to the transverse direction DT. The weft yarns 202 illustrated in [Fig. 3] are the weft yarns 202 of the columns N, N+1, N+2 and N+3 of weft yarns 202 of the central portion 210 shown in [Fig. 2].

[0073] In the example illustrated in [Fig. 3], the selvedge warp yarns 2031, 2032, 2033, 2034, 2035 and 2036 bind in pairs the weft yarns 202 from the same column N, N+1, N+2 and N+3 of weft yarns 202 of the central part 210. For example, the first selvedge warp yarn 2031 binds the first weft yarn and the second weft yarn of the first column N of weft yarns 202 of the central part 210, the second selvedge warp yarn 2032 binds the third weft yarn and the fourth weft yarn of the first column N of weft yarns 202 of the central part 210, the third selvedge warp yarn 2033 binds the fifth weft yarn and the sixth weft yarn of the first column N of weft yarns 202 of the central part 210, and so on.For example, the first selvedge warp yarn 2031 binds the first weft yarn and the second weft yarn of the first column N of weft yarns 202 of the central portion 210, binds the first weft yarn and the second weft yarn of the second column N+1 of weft yarns 202 of the central portion 210, binds the first weft yarn and the second weft yarn of the third column N+2 of weft yarns 202 of the central portion 210 and binds the first weft yarn and the second weft yarn of the fourth column N+3 of weft yarns 202 of the central portion 210.

[0074] The number of selvedge warp yarns 203 in each primary weaving plane is preferably less than the number of central warp yarns 201 in each weaving plane perpendicular to the transverse direction DT of the central portion 210 of the texture 200. Preferably, a first weaving plane comprises at least one portion in which the number of selvedge warp yarns 203 binding weft yarns 202 from of the same column of weft threads 202 of the central part 210 is twice less than the number of weft threads 202 of said column. In the case where the number of weft threads 202 from the same column of weft threads 202 of the central part 210 is odd, a number “twice less than the number of weft threads” designates the rounding up to the next whole number of half of said number of weft threads.

[0075] Furthermore, preferably, at least a portion of the weaving planes according to which the selvedge warp yarns 203 and the weft yarns 202 are woven into the first or second selvedge 121 or 122 are secondary weaving planes. The secondary weaving planes are weaving planes in which the selvedge warp yarns 203 are arranged on either side of sets of weft yarns 202 comprising weft yarns 202 originating from one or more same columns of weft yarns 202 of the central portion 210 of the texture 200. Thus, in the secondary weaving plane(s), the selvedge warp yarns 203 are present on the upper or lower surface of the selvedge 221 or 222 at each weft column originating from the central portion 210 of the texture 200. Consequently, the secondary weaving plane(s) comprise at least two selvedge warp yarns 203.Preferably, the secondary weaving plane(s) comprise only two selvedge warp threads 203, in order to ensure the maintenance of the weft threads 202 while limiting the density of threads in the selvedge 221 or 222.

[0076] The secondary weaving plane(s) thus make it possible to bind together all the layers of weft threads 202 so that they are well maintained along the thickness direction DE. The secondary weaving plane(s) complement the primary weaving planes to ensure the blocking of the weft threads 202 along the thickness direction DE in the selvedges 221 or 222 of the texture 200. Indeed, the primary weaving planes make it possible to block the weft threads 202 along the transverse direction DT by binding them in groups, but said groupings are not very tightly bound together. The use of secondary weaving planes in which selvedge warp threads 203 are arranged on either side of all the groupings of weft threads 202 coming from the same column of weft threads 202 makes it possible to tighten said groupings with each other.

[0077] [Fig. 4] illustrates a portion of an exemplary secondary weaving plane of the first or second selvedge 221 or 222 of the woven texture 200 perpendicular to the transverse direction DT. The weft yarns 202 illustrated in [Fig. 4] are the weft yarns 202 of the columns N, N+1, N+2 and N+3 of weft yarns 202 of the central portion 210 shown in [Fig. 2] and [Fig. 3].

[0078] In the example illustrated in [Fig.4], the selvedge warp threads 2038 and 2039 are arranged on either side of a set of weft threads 202 comprising weft threads 202 from the first and second columns N and N+1 of weft threads 202 of the central part 210 of the texture 200 and a set of weft threads 202 comprising weft threads 202 from the third and fourth columns N+2 and N+3 of weft threads 202 of the central part 210 of the texture 200. Thus, the selvedge warp thread 2038 is present on the upper surface of the selvedge 221 or 222 at the level of the first and second columns N and N+1 of weft threads from the central part 210 and present on the lower surface of the selvedge 221 or 222 at the level of the third and fourth columns N+2 and N+3 of weft threads from the central part 210. Conversely, the selvedge warp thread 2039 is present on the lower surface of the selvedge 221 or 222 at the level of the first and second columns N and N+1 of weft threads from the central part 210 and present on the upper surface of the selvedge 221 or 222 at the level of the third and fourth columns N+2 and N+3 of weft threads coming from the central part 210.

[0079] Preferably, the weaving plane(s) of the selvedge 221 or 222 closest to the central portion 210 are one or more secondary weaving planes. Thus, the wefts inserted into the thickness of the fibrous texture are better contained, which makes it possible to avoid distortions within the central portion of the texture.

[0080] Preferably, the weaving plane(s) of the selvedge 221 or 222 furthest from the central portion 210 are one or more secondary weaving planes. Thus, the end of the selvedge is well maintained and compacted, and does not risk separating in the thickness direction.

[0081] Preferably, the sequence of linking the weaving planes along the transverse direction DT in the selvedge 221 or 222 is done by alternating two consecutive secondary weaving planes with four consecutive primary weaving planes along the transverse direction DT. This sequence of linking the weaving planes allows a particularly satisfactory blocking of the weft threads 202 with an optimal compromise between a blocking of the weft threads 202 along the transverse direction DT thanks to the primary weaving planes, and a gathering and blocking of all the weft threads 202 along the thickness direction DE. In particular, it is desired to avoid more than four primary weaving planes being consecutive along the transverse direction DT. Indeed, by inserting one or more secondary weaving planes so as to avoid more than four consecutive primary weaving planes, the selvedge is better contained in the thickness direction DE.

[0082] It is desirable that the number of selvedge warp yarns woven in each primary or secondary weaving plane of the selvedge(s) perpendicular to the transverse direction DT be constant along the longitudinal direction DL. Indeed, the removal of selvedge warp yarns as weaving progresses in the longitudinal direction would generate free selvedge warp yarns likely to break. However, a break in a selvedge warp yarn can lead to anomalies in the weaving of the selvedge(s). or even the central part of the texture, and may require an unwanted interruption of the weaving. By keeping a constant number of woven selvedge warp yarns along the longitudinal direction, as illustrated in Figures 3 and 4, it is ensured that said selvedge yarns are well attached and have a low risk of breakage.

[0083] Figures 5 and 6 illustrate an exemplary embodiment of a woven texture comprising a variation in thickness along the longitudinal direction DL. The woven texture illustrated in Figures 5 and 6 comprises a central portion 310 and one or more selvedges 310. The woven texture is produced by three-dimensional weaving between a plurality of warp threads 301 and 303 and a plurality of weft threads 202. The woven texture illustrated in Figures 5 and 6 can be produced using the loom 100 illustrated in [Fig. 1].

[0084] The central portion 310 of the woven texture is produced by three-dimensional weaving between a plurality of central warp threads 301 and the plurality of weft threads 302.

[0085] [Fig.5] illustrates a portion of an example of a weaving plan of the central part 310 of the woven texture perpendicular to the transverse direction DT. In particular, [Fig.5] illustrates nine columns M, M+1, M+2, M+3, M+4, M+5, M+6, M+7 and M+8 of weft threads 302 of said example of weaving plan of the central part 310.

[0086] In the example illustrated in [Fig. 5], the first and second columns M and M+1 of weft threads 302 of the central part 310 each comprise twelve weft threads 202. The quantity of weft threads 202 in each column of weft threads 202 decreases along the longitudinal direction DL between the first column M of weft threads and the ninth column M+8 of weft threads. The ninth column M+8 of weft threads then comprises only eight weft threads 202 in the example illustrated in [Fig. 5],

[0087] In the example illustrated in [Fig. 5], the reduction in the number of weft threads 202 along the longitudinal direction DL is accompanied by a reduction in the number of central warp threads 301, i.e. central warp threads 301 are removed from the fiber texture. It is of course not outside the scope of the invention if the central portion 310 of the woven texture does not include a central warp thread outlet.

[0088] The weft yarns 302 from columns M, M+1, M+2, M+3, M+4, M+5, M+6, M+7 and M+8 of weft yarns 302 of the central portion 310 of the woven texture are woven three-dimensionally with the plurality of central warp yarns 301. In the example illustrated in [Fig. 5], the central warp yarns 301 are woven with the weft yarns 302 according to an interlock type weave in the central portion 310. It is of course not outside the scope of the invention if the central warp yarns 301 are woven with the weft yarns 302 according to another three-dimensional weaving weave in the central part 310. In order to obtain an interesting surface condition of the central part 310, a different weave can be used on the surface of the central part 310. Thus, in the example illustrated in [Fig.5], the central part 310 comprises a multisatin type weave on the surface.

[0089] The selvedge(s) 322 are produced by weaving between a plurality of selvedge warp threads 303 and the plurality of weft threads 302. The selvedge warp threads 303 are linked with the weft threads 302 in the selvedge(s) 322 according to successive weaving planes perpendicular to the transverse direction DT.

[0090] At least a portion of the weaving planes according to which the selvedge warp yarns 203 and the weft yarns 202 are woven into the first or second selvedge 121 or 122 are primary weaving planes as described above.

[0091] [Fig. 6] illustrates a portion of an exemplary primary weaving plane of the selvedge(s) 322 of the woven texture perpendicular to the transverse direction DT. The weft yarns 302 illustrated in [Fig. 6] are the weft yarns 302 of the columns M, M+1, M+2, M+3, M+4, M+5, M+6, M+7 and M+8 of weft yarns 302 of the central portion 310 shown in [Fig. 5].

[0092] In the example illustrated in [Fig.6], the selvedge warp yarns 3031, 3032, 3033, 3034, 3035, 3036 bind in pairs the weft yarns 302 from the same column M, M+1, M+2, M+3, M+4, M+5, M+6, M+7 and M+8 of weft yarns 302 of the central part 310. For example, the first selvedge warp yarn 3031 binds the first weft yarn and the second weft yarn of the first column M of weft yarns 302 of the central part 310, the second selvedge warp yarn 3032 binds the third weft yarn and the fourth weft yarn of the first column M of weft yarns 302 of the central part 310, the third selvedge warp yarn 3033 binds the fifth weft yarn and the sixth weft yarn of the first column M of weft yarns 302 of the central part 310, and so on.For example, the first selvedge warp yarn 3031 binds the first weft yarn and the second weft yarn of the first column M of weft yarns 302 of the central portion 310, binds the first weft yarn and the second weft yarn of the second column M+1 of weft yarns 302 of the central portion 310, binds the first weft yarn and the second weft yarn of the third column M+2 of weft yarns 302 of the central portion 310 and binds the first weft yarn and the second weft yarn of the fourth column M+3 of weft yarns 302 of the central portion 310.

[0093] Preferably, as illustrated in [Fig. 6], a first weaving plane comprises at least one portion in which the number of selvedge warp threads 303 binding weft threads 302 from the same column of weft threads 302 of the central portion 310 is half the number of weft threads 302 of said column. In the case where the number of weft threads 302 from the same column of weft threads 302 of the central portion 310 is odd, a number “half the number of weft threads weft" means the rounding up of half of said number of weft threads. In the example illustrated in [Fig.6], the first weaving plane includes a portion in which the number of selvedge warp threads 303 linking weft threads 302 from the same column of weft threads 302 of the central part 310 is half the number of weft threads 302 of said column, this portion including columns M, M+1, M+2 and M+3 of weft threads 302.

[0094] Furthermore, preferably, at least a portion of the weaving planes according to which the selvedge warp yarns 303 and the weft yarns 302 are woven into the first or second selvedge 121 or 122 are secondary weaving planes as described above.

[0095] Preferably, the number of selvedge warp yarns 303 woven in each primary or secondary weaving plane of the selvedge(s) 322 perpendicular to the transverse direction DT is constant along the longitudinal direction DL, even when the central portion 310 has variations in thickness or a variation in the number of weft yarns. Indeed, the removal of selvedge warp yarns 303 as weaving progresses in the longitudinal direction DL would generate free selvedge warp yarns likely to break. However, a break in a selvedge warp yarn can lead to anomalies in the weaving of the selvedge(s) or even of the central portion of the texture, and may require an undesired interruption of the weaving. By maintaining a constant number of woven selvedge warp yarns 303 along the longitudinal direction DL, as illustrated in [Fig.6], it is ensured that said selvedge threads 303 are well attached and have a low risk of breakage, even when the number of weft threads 302 per column of weft threads 302 of the central part 310 decreases along the longitudinal direction DL.

[0096] The warp and weft yarns used in the present invention, and in particular the warp and weft yarns of the central part, may be fibers, for example carbon, glass or ceramic fibers, or a mixture of such fibers. In particular, the woven texture may be made from fibers made of the following materials: silicon carbide, alumina, mullite, silica, an aluminosilicate, a borosilicate, or a mixture of several of these materials.

[0097] The woven texture can thus be intended to form the fiber reinforcement of a part made of composite material, for example a part made of ceramic matrix composite (CMC) or organic matrix composite (OMC). The woven texture can thus be intended to form the fiber reinforcement of a part made of composite material for an aeronautical engine, for example an aeronautical engine blade. Indeed, the use of organic matrix composite (OMC) and ceramic matrix composite (CMC) materials on aeronautical engines, replacing metallic materials, contributes to optimizing aircraft performance, in particular by improving the efficiency of the turbine. bomachine and by reducing the overall mass of the engine, thus significantly reducing harmful emissions to the environment.

[0098] Thus, the woven texture obtained by the weaving method described above can be shaped to obtain a fiber preform of the part to be manufactured. The shaping step can comprise compacting in order to obtain the desired volume ratio of fibers in each part of the fiber preform.

[0099] The fiber preform can then be densified to form a matrix in the porosities of the fiber preform, in order to obtain the composite material part. The densification of the fiber preform can be carried out in a well-known manner by impregnating said preform with one or more matrix precursors, then by treating the impregnated preform to form the matrix. Thus, the densification can be carried out in a well-known manner by injection molding techniques, for example resin injection molding techniques or "Resin Transfer Molding" (abbreviated "RTM"), suspension injection molding techniques or "Slurry Transfer Molding" (abbreviated "STM"), or by flexible membrane injection techniques. The densification or consolidation of the fiber preform can also be carried out in a well-known manner by chemical vapor infiltration or "Chemical Vapor Infiltration" (abbreviated "CVI").

[0100] The edge(s) of the fibrous texture are preferably retained in the final piece. However, it is of course not outside the scope of the invention if all or part of the edge(s) of the fibrous texture are removed after weaving.

Claims

Claims

1. A method of three-dimensionally weaving a texture (200) between a plurality of warp threads (201, 203; 301, 303) extending in a longitudinal direction (DL) and a plurality of columns of weft threads (202; 302), said weft threads (202; 302) extending in a transverse direction (DT), the texture (200) extending in the transverse direction (DT) between a first selvedge (221) and a second selvedge (222; 322), the texture (200) comprising a central portion (210; 310) present between the selvedge (211, 222; 322), the method being characterized in that at least one of the first or second selvedge (211, 222; 322) comprises at least one primary weaving plane perpendicular to the transverse direction (DT) in which the weft threads (202; 302) from the same column of weft threads (202; 302) of the central part (210; 310) of the texture (200) are linked by grouping, the weft threads (210;310) of the same grouping being aligned in the longitudinal direction (DL).;

2. A weaving method according to claim 1, wherein the weft yarn groupings (202; 302) in the primary weaving plane gather a number of weft yarns (202; 302) of between two and seven.

3. A weaving method according to claim 1 or 2, wherein the primary weaving plane comprises at least one portion in which the number of warp threads (203; 303) in the first or second selvedge (211, 222; 322) binding the weft threads (202; 302) from the same column of weft threads (202; 302) of the central portion (210; 310) of the texture (200) is half the number of weft threads (202; 302) of said column.

4. A weaving method according to any one of claims 1 to 3, wherein the warp threads (203; 303) of at least the first or second selvedge (211, 222; 322) bind the weft threads (202; 302) in a satin or plain weave pattern in the primary weaving plane.

5. A weaving method according to any one of claims 1 to 4, wherein at least the first or second selvedge (211, 222; 322) further comprises at least one secondary weaving plane perpendicular to the transverse direction (DT) in which the warp threads (203; 303) are arranged on either side of sets of weft threads (202; 302) comprising weft threads (202; 302) originating from one or several same columns of weft threads (202; 302) of the central part (210; 310) of the texture (200).

6. A weaving method according to claim 5, wherein the number of warp yarns (203; 303) in the secondary weaving plane is two.

7. A weaving method according to claim 5 or 6, wherein the weaving plane(s) of the first or second selvedge (211, 222; 322) closest to the texture (200) are secondary weaving planes.

8. A weaving method according to any one of claims 5 to 7, wherein the weaving plane(s) of the first or second selvedge (211, 222; 322) furthest from the texture (200) are secondary weaving planes.

9. A weaving method according to any one of claims 1 to 8, wherein the first or second selvedge (211, 222; 322) comprises no more than four consecutive primary weaving planes in the transverse direction (DT).

10. A weaving method according to any one of claims 1 to 9, wherein the central portion (310) of the texture has a reduction in the number of weft threads (302) per column of weft threads (302) in the longitudinal direction (DL), the number of warp threads (303) in the weaving planes of the first or second selvedge (322) remaining constant in the longitudinal direction (DL).

11. Method for manufacturing a part made of composite material comprising: - weaving a texture (200) by implementing the method according to any one of claims 1 to 10, - shaping the woven texture (200) obtained to obtain a preform of the part to be manufactured, - densifying the preform by a matrix so as to obtain the part made of composite material whose reinforcement is formed by the preform.

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