Three-dimensional weaving process with yarn exit

Abstract

Three-dimensional weaving process with yarn exit. The invention relates to a process for weaving a texture (200) between warp yarns (210) and weft yarns (220) using a loom (100) comprising at least one pole (130) adapted to pass through said loom (100) along a reference path (T130) and to draw a weft yarn (220). The process comprises at least the displacement of at least a portion of the warp yarns intended to be exited from the texture (200), such that said yarns are arranged on one side of the reference path (T130) and the remaining warp yarns not exited are arranged on the other side of the reference path (T130), followed by the passage of the pole (130) through the loom (100) along the reference path (T130) without drawing any weft yarn. Figure for the abstract: Fig. 2

Description

Title of the invention: Three-dimensional weaving method with yarn outlet Technical field

[0001] The present invention relates to the three-dimensional weaving of woven textures using a Jacquard type loom, and in particular textures having variations in thickness requiring thread outlets. 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, in the name of the applicant.

[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, said lance having a fixed vertical position. 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.

[0005] When it is desired to produce thick woven textures comprising a variation in thickness, it may be necessary to bring out threads at the location of the decrease in thickness so that they are not woven. In order to maintain a satisfactory and continuous surface condition of the woven texture, it is generally sought to bring out threads present in underlying layers of warp threads, which are therefore not present on the surface. Thus, by actuating the control threads, the warp threads are moved in the harness so that the warp threads to be brought out pass through the surface layer of warp threads and are placed outside the path of the rapier. The other threads are then weaved conventionally, from the upper surface layer of warp threads to the lower surface layer of warp threads.

[0006] However, the crossing of the warp threads to be taken out with the surface warp threads can generate friction and tensions, in particular when the warp threads to be taken out must pass through many layers of warp threads. The associated control thread eyelets can thus be poorly positioned in the harness and significant tensions can be generated in the control threads. In particular, a phenomenon of advance of the control threads can be observed, which results in a vertical misalignment of the control threads which engage in the reed of the loom. The friction and the stresses applied to the control threads can then cause regular interruptions in the weaving, or even a prolonged stoppage of the weaving. In addition, if the warp threads are poorly positioned in the harness, warp threads to be taken out can become blocked at the level of the layers of surface warp threads, and thus be woven by mistake. Statement of the invention

[0007] The present invention aims to remedy the aforementioned drawbacks by proposing a weaving method allowing the production of woven textures by three-dimensional weaving comprising yarn outlets through layers of warp yarns.

[0008] To this end, the invention proposes a method for three-dimensional weaving of a texture between a plurality of layers of warp threads superimposed in a vertical direction and a plurality of weft threads extending in a horizontal direction, the weaving being carried out by means of a loom comprising a plurality of control threads, a first end of each control thread being connected to a Jacquard mechanism capable of moving the control threads in the vertical direction between a neutral position and at least one position for opening the warp threads, each control thread being further provided with an eyelet crossed by a warp thread, the loom further comprising at least one lance present downstream of the control threads capable of crossing the loom in a horizontal fixed reference path and of drawing a weft thread from a bobbin,

[0009] characterized in that the method further comprises at least one step of outputting warp threads comprising:

[0010] - the displacement in the vertical direction of all or part of the warp threads of at least at least one layer of warp threads underlying the plurality of layers of warp threads, said displaced warp threads being intended to be taken out of the texture, over a determined distance extending beyond a layer of warp threads present on the surface of the plurality of layers of warp threads, such that the displaced warp thread(s) are arranged above the reference path and the remainder of the non-exited warp threads are arranged below the reference path, or such that the displaced warp thread(s) are arranged below the reference path and the the remainder of the unpulled warp threads is placed above the reference path, then

[0011] - the crossing of the loom by the lance along the reference path without pulling any thread of frame.

[0012] By performing an empty lance stroke, it is ensured that the warp threads to be taken out are correctly separated from the layers of warp threads to be woven, even when the warp threads to be taken out must cross numerous layers of surface warp threads or even when a significant number of warp threads have been moved in the harness. It is therefore ensured that the warp threads to be taken out are correctly positioned in relation to the warp threads to be woven. This facilitates the movement of the control threads and the associated eyelets in the harness, which are arranged in the correct position without generating tension or friction. This greatly limits the stresses on the control threads, which allows for smoother weaving with few interruptions. Weaving errors generated by poor placement of the control threads in the harness are also reduced. The weaving speed can therefore be increased, while improving the quality of the weaving obtained.

[0013] According to a particular embodiment of the invention, during the weaving of at least one weft column, a plurality of layers of underlying warp threads is intended to be taken out of the texture beyond one of the layers of warp threads present on the surface of the plurality of layers of warp threads, the following step of taking out warp threads being repeated for each layer of warp threads to be taken out beyond said layer present on the surface:

[0014] moving in the vertical direction the layer of warp threads to be taken out over a determined distance extending beyond the layer of warp threads present on the surface of the plurality of layers of warp threads, such that the moved layer of warp threads is arranged above the reference path and below the layers of warp threads previously moved intended to be taken out of the texture and the remainder of the untaken warp threads are arranged below the reference path, or such that the moved layer of warp threads is arranged below the reference path and above the layers of warp threads previously moved intended to be taken out of the texture and the remainder of the untaken warp threads are arranged above the reference path; then the rapier passing through the loom along the reference path without pulling any weft thread.

[0015] By carrying out the exits of the layers of warp threads one after the other, with a vacuum lance stroke for each layer of warp thread moved, the number of simultaneous crossings with the surface layer of warp threads is limited. The exit of the layers of warp threads is therefore facilitated and is carried out by generating very few constraints at the harness level.

[0016] According to another particular embodiment of the invention, the wire output step warp also includes, after the lance has passed through the loom without pulling any weft thread:

[0017] - the movement in the vertical direction of a part of the displaced warp threads or a portion of the displaced layer such that said portion of the displaced warp threads or displaced layer is arranged below the reference path and the other portion of the displaced warp threads or displaced yarn layer is arranged above the reference path, then

[0018] - the crossing of the loom by the lance according to the reference path by pulling a thread of weft so as to bind together the displaced warp threads.

[0019] Thus, after having taken out the warp threads using vacuum lance strokes, the taken out warp threads can be linked together to reduce the risks of certain taken out warp threads being mistakenly woven with the texture, and to facilitate the subsequent cutting of the taken out warp threads.

[0020] Preferably, the output warp threads are bonded with a two-dimensional weave weave.

[0021] According to another particular embodiment of the invention, the loom further comprises a guide device present downstream of the plurality of control threads and the rapier, the guide device being able to move in the vertical direction so as to move the woven texture upwards or downwards relative to a horizontal reference plane comprising the reference path.

[0022] Since the reference path of the lance is fixed vertically, such a guide device capable of vertically moving the texture makes it easier to make lance strokes, empty or with a weft thread, in the highest and lowest layers of warp threads. In addition, such a guide device makes it possible to move the texture as each weft column is weaved to position it in the best position in order to facilitate the uncrossing of the warp threads and to improve the positioning of the texture relative to the shed opening used.

[0023] The guide device may further comprise an upper guide bar and a lower guide bar configured to be positioned in contact with the woven texture and on either side of said texture in the vertical direction, the minimum value of the spacing between the guide bars corresponding to the thickness of the uncompacted woven texture.

[0024] Furthermore, the woven texture according to the invention may be abundant and require subsequent compaction. Thus, it is preferable to have sufficient spacing between the guide bars so as not to deform the texture. Furthermore, the proper production of warp thread outlets may require very large shed openings. However, too limited a spacing of the guide bars may prevent the implementation of wide crowd openings.

[0025] According to another particular embodiment of the invention, the spacing between the guide bars increases during the movement in the vertical direction of all or part of the warp threads intended to be taken out of the texture over a determined distance extending beyond a layer of warp threads present on the surface of the plurality of layers of warp threads.

[0026] Indeed, the production of warp thread outlets requires large height amplitudes of the eyelets in the harness, as well as very wide shed openings. By increasing the spacing between the guide bars at the crossing between the threads to be removed and the surface threads, the possible shed opening is greatly increased and the risk of generating tensions on the eyelets of the harness is reduced.

[0027] According to another particular embodiment of the invention, the guide bars of the guide device are configured to move in the vertical direction as a function of the vertical position of the eyelets of the harness during the movement in the vertical direction of all or part of the warp threads intended to be taken out of the texture over a determined distance extending beyond a layer of warp threads present on the surface of the plurality of layers of warp threads, so that in each plane of the loom perpendicular to the reference path, the length between the harness and the woven texture of the lowest warp thread located above the reference path corresponds to between 90% and 110% of the length between the harness and the woven texture of the highest warp thread located below the reference path.

[0028] Thus, the movement of the guide bars of the guide device is a function of the positions of the eyelets in the harness. By ensuring that the lengths of the crossing wires are similar, it is possible to avoid generating significant tensions in certain wires which could pull on the eyelets and generate stresses in the harness.

[0029] According to another particular embodiment of the invention, the guide device is configured to move between a first position and a second position in the vertical direction as a function of the vertical position of the eyelets of the harness after the movement in the vertical direction of all or part of the warp threads intended to be taken out of the texture over a determined distance extending beyond a layer of warp threads present on the surface of the plurality of layers of warp threads, so that in each plane of the weaving loom perpendicular to the reference path,the length between the harness and the woven texture of the highest warp yarn located below the reference path when the guide device is in the first position is between 90% and 110% of the length between the harness and the woven texture of said warp yarn when it is the lowest located above the reference path when the guide device is in the second position.

[0030] Thus, the warp threads swing from the lower edge of the shed to the upper edge of said crowd after a lance stroke do not undergo too much tension, thus facilitating the crossing of threads.

[0031] According to another particular embodiment of the invention, the warp and weft threads are carbon, glass or ceramic fibers.

[0032] According to another particular embodiment of the invention, the woven texture is intended to form a fibrous reinforcement for a composite material part of an aeronautical engine.

[0033] Indeed, the manufacture of numerous parts in composite material for aeronautics involves producing a three-dimensional weave of significant thickness requiring wire outlets to produce variations in thickness. Brief description of the drawings

[0034] [Fig. 1] [Fig. 1] is a schematic perspective view of a Jacquard type loom in neutral position.

[0035] [Fig.2] [Fig.2] is a schematic perspective view of the loom of the washed figure a crowd creation.

[0036] [Fig.3] [Fig.3] is a schematic sectional view of a woven texture produced by the method of the invention.

[0037] [Fig.4] [Fig.4] is a schematic sectional view of the loom of Figures 1 and 2 during the exit of a first layer of warp threads through the upper layer of warp threads of a first weft column.

[0038] [Fig.5] [Fig.5] is a schematic sectional view of the loom of Figures 1 and 2 during the exit of a second layer of warp threads through the upper layer of warp threads of the first weft column.

[0039] [Fig.6] [Fig.6] is a schematic sectional view of the loom of Figures 1 and 2 during weaving of the upper layer of warp yarns of the first weft column.

[0040] [Fig.7] [Fig.7] is a schematic sectional view of the loom of Figures 1 and 2 during weaving of a layer of warp yarns underlying the first weft column.

[0041] [Fig.8] [Fig.8] is a schematic sectional view of the loom of Figures 1 and 2 at the end of weaving all the underlying warp yarn layers to be woven from the first weft column.

[0042] [Fig.9] [Fig.9] is a schematic sectional view of the loom of Figures 1 and 2 during weaving of the lower layer of warp yarns of the first weft column.

[0043] [Fig. 10] [Fig. 10] is a schematic sectional view of the loom of Figures 1 and 2 as a fifth layer of warp yarns is taken out through the layer of upper warp threads of a second weft column.

[0044] [Fig. 11] [Fig. 11] is a schematic sectional view of the loom of Figures 1 and 2 at the end of weaving all layers of warp yarns of the second weft column. 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.

[0046] The woven texture may, for example, have a three-dimensional weave of the interlock 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] Figures 1 and 2 illustrate 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 extending in length in a horizontal direction DH and in thickness in a vertical direction Dv by weaving a plurality of layers of warp threads 210 with a plurality of layers of weft threads 220.

[0048] The loom is equipped with a Jacquard mechanism 110 supported by a superstructure not shown in Figures 1 and 2. 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 Figures 1 and 2, 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 vertical direction Dv. The harness 120 may also comprise a tying board 122.

[0049] Each control thread 121 comprises an eyelet 121a crossed by a warp thread 210. Each warp thread 210 of the loom 100 passes through an eyelet 121a of the harness 120. The warp threads 210 are organized at the harness 120 of the loom 100 in a plurality of horizontal layers and vertical columns which are manipulated by the loom 100 to allow the insertion of weft threads 220 according to the weaving pattern(s) programmed in the loom 100. The weft threads 220 are inserted between the warp threads 210 by column extending in the vertical direction Dv. In order to allow the introduction of each column of weft threads 220 during the weaving of the texture 200, a warp thread take-up system 210 (not shown in Figures 1 and 2) is associated with the loom 100. This system, placed downstream of the loom 100, has the role of holding all the warp threads 210 together in a clamping device and of allowing the warp threads 210 to advance by a determined distance in the horizontal direction DH after the insertion of each weft column 220.

[0050] The terms “upstream” and “downstream” are defined here according to the direction of advance of the warp threads 210 in the loom 100, that is to say according to the weaving direction, along the horizontal direction DH.

[0051] The control threads 121 and their associated eyelet 121a are able to move in the vertical direction Dv. 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 shed is created and all the warp threads 210 extend parallel to the horizontal direction DH.

[0052] When creating a shed, as illustrated in [Fig. 2], 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 2101 of warp threads from a lower layer 2102 of warp threads by an opening F, called a shed. Several different sheds can be produced by modifying the warp threads raised or lowered using the control threads 121.

[0053] 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 FIGS. 1 and 2) making it possible to drive the rod 131 with a back-and-forth movement along a horizontal reference path Tno, said reference path Tno being fixed relative to the frame 113 of the loom 100. The reference path Tno belongs to a horizontal reference plane PH extending along the horizontal direction DH. The other end of the rod 131 is provided with a gripper 132 which, after having passed through the shed during the outward journey of the rod 131, can come to grip a weft thread 220 stored on a bobbin 140 to unwind it in the shed during the return journey of the rod 131.The weft yarn 220 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 yarn(s) 220 introduced into the shed. In accordance with the invention, the rod 131 can also make the round trip without the clamp 132 coming to grip a weft yarn 220: a free lance stroke is then made. The lance 130 is then ready to grip a new weft yarn 220 from the bobbin. 140 and placing it either in the same shed or in a different shed depending on the defined weave. The woven texture 200 is thus gradually formed, presenting a three-dimensional weave between the warp threads 210 and the weft threads 220.

[0054] Preferably, the loom 100 further comprises a guide device 170 for the woven texture 200 present downstream of the control threads 121 and the rapier 130. Such a guide device 170 is described in particular in the document FR 3 074 195 A1. More generally, guide means are known from the document EP 0 573 132 A1. In the example described here, the guide device 170 may comprise a lower guide bar 171 and an upper guide bar 172 each connected to an actuating means (not shown in FIGS. 1 and 2) which is capable on the one hand of holding the woven texture 200 and on the other hand of moving the guide bars 171 and 172 in the vertical direction Dv. The guiding device 170 makes it possible to move the woven texture in the vertical direction Dv upwards or downwards relative to the horizontal reference plane PH comprising the horizontal reference path Tuode the lance 130.It is thus easier to create crowds at the level of the lower or upper layers of warp threads 210, even with a large number of layers of warp threads 210 superimposed in the vertical direction Dv.

[0055] As illustrated in the figures, the guiding device 170 can move the entire woven texture in the vertical direction Dv. According to another example not illustrated, a selvedge zone arranged on each edge of the woven texture can be moved in the vertical direction Dv independently of the rest of the woven texture, by a guiding device specific to this zone. In other words, the guiding device can be independent of the selvedge zones, each selvedge zone being able to have a guiding device specific to this zone, so as to move the selvedge zone in the vertical direction Dv.

[0056] The weaving method according to the invention makes it possible to produce a woven texture 200 comprising at least a first portion 201 and a second portion 203. An example of a woven texture 200 produced by the method of the invention is illustrated schematically in [Fig. 3]. For reasons of clarity and simplification of the diagrams, the texture represented in the example illustrated in Figures 3 to 11 comprises a small number of warp threads and weft threads, and the weave of the said texture is not shown.

[0057] The first portion 201 of the texture 200 is produced by three-dimensional weaving between a first number of warp threads 210 and a first number of weft threads 220. The second portion 203 of the texture 200 is produced by three-dimensional weaving between a second number of warp threads 210, less than the first number of warp threads 210, and a second number of weft threads 220. The second number of weft threads 220 is preferably less than the first number of weft threads 220. Thus, the texture 200 may have a variation in thickness, the second portion 203 being able to be less thick than the first portion 201.

[0058] The texture 200 also comprises a transition portion 202 between the first portion 201 and the second portion 203, in which the number of woven warp threads 210 decreases from the first portion 201 to the second portion 203. The transition portion 202 connects the first portion 201 to the second portion 203 in the weaving direction. The transition portion 202 may correspond to a single weft column or to several weft columns N and N+1 of the texture 200.

[0059] The weaving method according to the invention comprises a first step, in which the three-dimensional weaving of the first portion 201 of the texture 200, which is preferably a portion of high thickness, is carried out. The first portion 201 of the texture 200 is produced in a well-known manner by three-dimensional weaving between the first number of warp threads 210 and the first number of weft threads 220 using the loom 100 previously described.

[0060] When the weaving of the first portion 201 of the texture 200 is completed, the second step of the weaving method according to the invention begins, in which the transition portion 202 of the texture 200 is produced. During this second step, a certain number of warp threads are therefore removed from the weaving to reduce the first number of warp threads and obtain the second number of warp threads.

[0061] In order to obtain a woven texture 200 with a satisfactory and continuous surface condition between the first portion 201 and the second portion 203, it is desired to remove from the weaving warp threads belonging to underlying warp thread layers, i.e. not belonging to the upper warp thread layer 210h or to the lower warp thread layer 210b. Preferably, it is desired to remove warp threads not belonging to the upper warp thread layers or to the lower warp thread layers. Consequently, each warp thread or each layer of warp threads that it is desired to remove from the weaving must pass through one or more upper or lower surface warp thread layers in the vertical direction Dv.

[0062] For each weft column of the transition portion 202 to be produced, if it is desired to remove warp threads from the weaving through the upper surface warp thread layer 210h in the vertical direction Dv, the sub-steps described below are carried out.

[0063] According to a first sub-step, the warp threads to be removed, or the entire layer(s) of warp threads to be removed, are placed above the reference path Tnode the lance 130 relative to the vertical direction Dv, and the rest of the warp threads are placed below the reference path Tnode the lance 130 relative to the vertical direction Dv. A shed is thus created separating on the one hand the warp threads to be removed, or the entire layer(s) of warp threads to be removed, from the rest of the warp threads, said crowd comprising the reference path Tno. This configuration is obtained by actuating the control wires 121 of the harness 120, so as to arrange the eyelets 121a crossed by warp threads to be removed above the eyelets 121a crossed by the rest of the warp threads 210.

[0064] The terms “above” and “below” must be understood in the vertical direction Dv, and preferably in relation to the direction of gravity.

[0065] Preferably, this configuration is also obtained by arranging the lower and upper guide bars 171 and 172 of the guide device 170 of the woven texture 200 in a vertical position making it possible to arrange the warp threads to be removed, or the entire layer(s) of warp threads to be removed, above the reference path T i30 of the lance 130, and so as to arrange the remainder of the warp threads 210 below the reference path Tno of the lance 130.

[0066] Preferably, the vertical position of the lower and upper guide bars 171 and 172 of the guide device 170 is determined so that, in each plane of the loom 100 perpendicular to the reference path Tno of the lance 130, the length between the harness 120 and the woven texture 200 of the warp yarn which delimits the lower edge of the shed corresponds to between 90% and 110% of the length between the harness 120 and the woven texture 200 of the warp yarn which delimits the upper edge of the shed. The length between the harness 120 and the woven texture 200 is understood as the length between the point of said warp yarn present at the downstream end of the harness 120 and the point of said warp yarn present at the upstream end of the woven texture 200.This avoids significant differences in yarn length between the warp yarns to be removed placed above the reference path Tno of the lance 130 and the other warp yarns placed below the reference path Tno of the lance 130, which further reduces the risk of tension in the harness and facilitates the crossing between the warp yarns to be removed and the surface warp yarns.

[0067] When the warp threads to be removed are suitably positioned relative to the other warp threads 201 and relative to the reference path Tno of the lance 130, a second sub-step is carried out in which the lance 130 is sent so that it passes through the loom 100 along the reference path Tno without pulling any weft thread 220. Thus, the lance 130 carries out an “airpick”, also called an “airpick”. This airpick makes it possible in particular to properly position the warp threads to be removed relative to the other warp threads 210, for example when the warp threads to be removed must pass through more than four layers of warp threads. The comb 160 can be folded down after the airpick has been carried out. The second sub-step is carried out after the first sub-step.

[0068] The first and second sub-steps can be repeated several times in each frame column of the transition portion to be carried out when it is desired removing from the weaving through the upper surface warp yarn layer 210h warp yarns belonging to underlying warp yarn layers. Thus, the first and second sub-steps can be carried out for each layer of warp yarns to be taken out through the upper surface layer 210h. Thus, by carrying out an empty lance stroke 130 between each layer of warp yarns to be taken out in the same weft column of the transition portion 202 to be produced, it is easier to position the layers of warp yarns to be taken out relative to each other and to position the layers of warp yarns to be taken out relative to the other warp yarns 210, for example when the warp yarns to be taken out must pass through more than four layers of warp yarns.Carrying out an empty lance stroke 130 for each layer of warp threads output, or for each part of the layer of warp threads output, also makes it easier to move the mass of warp threads to be output upwards while limiting the stresses and frictions in the harness 120. In addition, in the same weft column of the transition portion 202 to be produced, the layers of warp threads to be output can be progressively output one after the other, as illustrated in FIGS. 4 and 5. Thus, by multiplying the number of first sub-steps for each weft column, the number of simultaneous crossings between the warp threads to be output and the warp threads of the surface layer is limited during each first sub-step, thus reducing the massive movements of control threads in the harness 120 and consequently reducing the friction and stresses in the harness 120.

[0069] Figures 4 to 11 illustrate the second step of the method of the invention, according to which the transition portion 202 of the texture 200 is produced. In the example illustrated in Figures 4 to 11, it is desired to produce the woven texture 200 of [Fig. 3] whose second portion 203 comprises six fewer layers of warp threads than the first portion 201, by removing three layers of warp threads 211, 212, 216 through the upper layer of warp threads 210h and by removing three layers of warp threads 213, 214, 215 through the lower layer of warp threads 210b.It is thus desired to produce a transition portion 202 between the first and second portions 201 and 203 comprising a first weft column N, in which two layers of warp threads 211 and 212 are removed through the upper warp thread layer 21 Oh and two layers of warp threads 213, 214 through the lower warp thread layer 210b, and a second weft column N+1, in which a fifth layer of warp threads 215 is removed through the upper warp thread layer 21 Oh and a sixth layer of warp threads 216 through the lower warp thread layer 210b.

[0070] In the example illustrated in [Fig.4], the first step of weaving the first portion 201 of the texture 200 is completed and the second step of weaving begins. the transition portion 202 of the texture 200 in the first weft column N. In [Fig. 4], the first and second sub-steps are carried out a first time for the first layer of warp threads 211 to be removed. Thus, the eyelets 121a crossed by the warp threads of the first layer of warp threads 211 to be removed are arranged above the eyelets 121a crossed by the other warp threads 210, so as to open a shed separating the first layer of warp threads to be removed 211 from the other warp threads 210. Thus, the shed also separates the first layer of warp threads 211 to be removed from the other layers of warp threads to be removed 212, 213, 214, 215, 216.

[0071] Preferably, the lower and upper guide bars 171 and 172 of the guide device 170 of the woven texture 200 are also moved in the vertical direction Dv so as to place the first layer of warp threads to be output 211 above the reference path Tnode the lance 130 and so as to place the other layers of warp threads below the reference path Tnode the lance 130.

[0072] Furthermore, the vertical position of the lower and upper guide bars 171 and 172 of the guide device 170 is determined so that, in each plane of the loom 100 perpendicular to the reference path Tno of the rapier 130, the length between the harness and the woven texture of the warp yarn of the upper surface warp yarn layer 210h which delimits the lower edge of the shed is between 90% and 110% of the length between the harness and the woven texture of the warp yarn of the first warp yarn layer 211 to be removed which delimits the upper edge of the shed.This avoids significant differences in the length of the yarns between the first layer of warp yarns 211 to be taken out and the upper surface warp yarn layer 210h, which facilitates the crossing between the warp yarns to be taken out and the surface warp yarns without generating tensions in the harness, in particular between the eyelets and the warp yarns passing through them.

[0073] Furthermore, the movement of the guide device 170 from a first position to a second position after a rapier stroke is carried out so that, in each plane of the loom 100 perpendicular to the reference path Tno of the rapier 130, the length between the harness and the woven texture of a warp thread delimiting the lower edge of the shed when the guide device 170 is in the first position is between 90% and 110% of the length between the harness and the woven texture of said warp thread when it delimits the upper edge of the shed when the guide device is in the second position. Thus, the warp threads tilting from the lower edge of the shed to the upper edge of said shed after a rapier stroke do not undergo excessive tension, thus facilitating thread crossings.

[0074] At the end of this first sub-step, the first layer of warp threads to be output 211 is arranged above the reference path Ti30 of the lance 130 while the other layers of warp threads are arranged below the reference path Ti30 of the lance 130. Thus, the other layers of warp threads to be taken out 212, 213, 214, 215, 216 are also arranged below the reference path Tnode the lance 130. A free lance stroke 130 is then carried out in accordance with the second sub-step, as illustrated in [Fig.4].

[0075] Then, still in the first weft column N, the first and second sub-steps are carried out for the second layer of warp threads to be removed 212, as illustrated in [Fig. 5]. Thus, the eyelets 121a crossed by the warp threads of the first and second layers of warp threads to be removed 211 and 212 are arranged above the eyelets 121a crossed by the other warp threads, so as to open a shed separating the first and second layers of warp threads to be removed 211 and 212 from the other warp threads 210. Thus, the shed also separates the first and second layers of warp threads to be removed 211 and 212 from the other layers of warp threads to be removed 213, 214, 215, 216.

[0076] Preferably, at least one of the lower and upper guide bars 171 and 172 of the guide device 170 of the woven texture 200 is moved upwards in the vertical direction Dv so as to place the first and second layers of warp threads to be output 211 and 212 above the reference path Tno of the lance 130 and so as to place the other layers of warp threads below the reference path Tno of the lance 130.

[0077] At the end of this first sub-step, the first and second layers of warp threads to be output 211 and 212 are arranged above the reference path Tno of the lance 130 while the other layers of warp threads are arranged below the reference path Ti30 of the lance 130. Thus, the other layers of warp threads to be output 213, 214, 215, 216 are also arranged below the reference path Ti30 of the lance 130. A free lance stroke 130 is then carried out in accordance with the second sub-step, as illustrated in [Fig.5].

[0078] In the example illustrated in Figures 4 to 10, only two layers of warp threads 211 and 212 are removed through the upper layer of warp threads 210h in the first weft column N of the transition portion 202 to be produced. It is of course not outside the scope of the invention if a single layer of warp threads or more than two layers of warp threads are removed through the upper layer of warp threads in a weft column of the transition portion to be produced. It is also not outside the scope of the invention if the layer of warp threads to be removed does not correspond to a complete layer of warp threads in the loom.

[0079] The first and second sub-steps can be carried out for each layer of warp threads to be output through the upper layer of warp threads. However, it is of course not outside the scope of the invention if the first and second sub-steps are carried out for only a portion of the layers of warp threads output through the upper layer of warp threads.

[0080] For each weft column N, N+1 of the transition portion 202 to be produced, when the desired layers of warp yarns have been brought out through the upper layer of warp yarns 210h, the underlying layers of warp yarns to be woven are conventionally weaved. Conventional weaving may include unlinkings. If it is not desired to bring out warp yarns through the lower layer(s) of warp yarns in said weft column, all the layers of warp yarns to be woven may be conventionally weaved. If it is desired to bring out warp yarns through the lower layer(s) of warp yarns in said weft column, all the underlying layers of warp yarns to be woven may be conventionally weaved, excluding the lower surface layers of warp yarns, as illustrated in FIGS. 6 to 9.

[0081] The layers of warp threads to be taken out 213 and 214 through the layer of lower surface warp threads 210b in the vertical direction Dv can also be taken out by performing vacuum lance strokes to properly uncross the warp threads.

[0082] For each weft column of the transition portion 202 to be produced, if it is desired to remove warp threads from the weaving through the lower surface warp thread layer 210b in the vertical direction Dv, the sub-steps described below are carried out.

[0083] According to a third sub-step, the warp threads to be removed, or the entire layer(s) of warp threads to be removed, are arranged below the reference path T of the lance 130, and the warp threads to be woven and any other warp threads to be removed are arranged above the reference path T of the lance 130. If warp threads have been taken out through the lower layer of warp threads 210b in the previous weft columns, these taken out warp threads are arranged below the reference path T i30 of the lance 130 and below the warp threads to be removed during this third sub-step.

[0084] A shed is thus created separating on the one hand the warp threads to be removed, or the entire layer(s) of warp threads to be removed, from the warp threads to be woven and any other warp threads to be removed, said shed comprising the reference path Ti30 of the lance 130. This configuration is obtained by actuating the control threads 121 of the harness 120, so as to arrange the eyelets 121a crossed by the warp threads to be removed below the eyelets 121a crossed by the rest of the warp threads, with the exception of the warp threads already taken out through the lower surface layer of warp threads 210b.

[0085] Preferably, this configuration is also obtained by arranging the lower and upper guide bars 171 and 172 of the texture guide device 170 woven 200 at a vertical position Dv allowing the warp threads to be removed, or the entire layer(s) of warp threads to be removed, to be arranged below the reference path Tnode of the lance 130, and so as to arrange the remainder of the warp threads, with the exception of the warp threads already taken out through the lower surface layer of warp threads, above the reference path Ti30 of the lance 130.

[0086] Preferably, the vertical position of the lower and upper guide bars 171 and 172 of the guide device 170 is determined so that, in each plane of the loom 100 perpendicular to the reference path Tno of the lance 130, the length between the harness 120 and the woven texture 200 of the warp yarn which delimits the lower edge of the shed corresponds to between 90% and 110% of the length between the harness 120 and the woven texture 200 of the warp yarn which delimits the upper edge of the shed. The length between the harness 120 and the woven texture 200 is understood as the length between the point of said warp yarn present at the downstream end of the harness 120 and the point of said warp yarn present at the upstream end of the woven texture 200.This avoids significant differences in yarn length between the warp yarns to be removed placed above the reference path Ti30 of the lance 130 and the other warp yarns placed below the reference path Ti30 of the lance 130, which further reduces the risk of tension in the harness and facilitates the crossing between the warp yarns to be removed and the surface warp yarns.

[0087] Furthermore, the movement of the guide device 170 from a first position to a second position after a rapier stroke is carried out so that, in each plane of the loom 100 perpendicular to the reference path Tno of the rapier 130, the length between the harness and the woven texture of a warp thread delimiting the lower edge of the shed when the guide device 170 is in the first position is between 90% and 110% of the length between the harness and the woven texture of said warp thread when it delimits the upper edge of the shed when the guide device is in the second position. Thus, the warp threads tilting from the lower edge of the shed to the upper edge of said shed after a rapier stroke do not undergo excessive tension, thus facilitating thread crossings.

[0088] When the warp threads to be removed are suitably positioned relative to the other warp threads and relative to the reference path Ti30 of the lance 130, a fourth sub-step is carried out in which the lance 130 is sent so that it passes through the loom 100 along the reference path Ti30 without pulling any weft thread 130. Thus, the lance 130 carries out an “empty stroke”, also called an “airpick”. This empty stroke makes it possible in particular to properly position the warp threads to be removed relative to the other warp threads. The comb 160 can be folded down after the empty stroke has been carried out. The fourth sub-step is carried out after the third sub-step.

[0089] The third and fourth sub-steps can be repeated several times in each weft column of the transition portion 202 to be produced when it is desired to remove from the weaving through the upper surface warp yarn layer 210h warp yarns belonging to different warp yarn layers. Thus, the third and fourth sub-steps can be carried out for each layer of warp yarns to be taken out through the lower surface layer 210b. Thus, by carrying out an empty lance stroke 130 between each layer of warp yarns to be taken out in the same weft column of the transition portion 202 to be produced, it is easier to position the layers of warp yarns to be taken out relative to each other and to position the layers of warp yarns to be taken out relative to the other warp yarns.Performing an empty lance stroke 130 for each layer of warp threads output also makes it easier to move the mass of warp threads upwards by limiting the stresses and frictions in the harness 120. In addition, in the same weft column of the transition portion 202 to be produced, the layers of warp threads to be output can be progressively output one after the other. Thus, by multiplying the number of third sub-steps for each weft column, the number of simultaneous crossings between the warp threads to be output and the warp threads of the surface layer is limited during each third sub-step, thus reducing the massive movements of control threads in the harness 120 and consequently reducing the friction and stresses in the harness 120.

[0090] In the example illustrated in [Fig. 10], the second step of weaving the transition portion 202 of the texture 200 is carried out in the second weft column N+1 after having completed the first weft column N. In [Fig. 10], the third and fourth sub-steps are carried out for the fifth layer of warp yarns 215 to be removed. Thus, the eyelets 121a through which the warp yarns of the fifth layer of warp yarns 215 to be removed are arranged below the eyelets 121a through which the other warp yarns 210 pass, except for the warp yarns of the third and fourth layers 213 and 214 already removed through the lower surface warp yarn layer 210b in the weft column N, so as to open a shed separating the fifth layer of warp yarns to be removed 215 from the other warp yarns to be woven or removed.

[0091] Preferably, the lower and upper guide bars 171 and 172 of the guide device 170 of the woven texture 200 are also moved in the vertical direction Dv so as to place the fifth layer of warp threads to be taken out 215 below the reference path Tu of the lance 130 and so as to place the other layers of warp threads to be woven or taken out above the reference path Ti30 of the lance 130.

[0092] Furthermore, the vertical position of the lower and upper guide bars 171 and 172 of the guide device 170 is determined so that, in each plane of the loom 100 perpendicular to the reference path Tno of the rapier 130, the length between the harness and the woven texture of the warp yarn of the fifth layer of warp yarns to be withdrawn 215 which delimits the lower edge of the shed corresponds to between 90% and 110% of the length between the harness and the woven texture of the warp yarn of the lower surface warp yarn layer 210b which delimits the upper edge of the shed. Thus, significant differences in yarn length between the fifth layer of warp yarns 215 to be withdrawn and the lower surface warp yarn layer 210b are avoided, which facilitates the crossing between the warp yarns to be withdrawn and the surface warp yarns without generating tensions in the harness, in particular between the eyelets and the warp yarns passing through them.

[0093] Furthermore, the movement of the guide device 170 from a first position to a second position after a rapier stroke is carried out so that, in each plane of the loom 100 perpendicular to the reference path Tno of the rapier 130, the length between the harness and the woven texture of a warp thread delimiting the lower edge of the shed when the guide device 170 is in the first position is between 90% and 110% of the length between the harness and the woven texture of said warp thread when it delimits the upper edge of the shed when the guide device is in the second position. Thus, the warp threads tilting from the lower edge of the shed to the upper edge of said shed after a rapier stroke do not undergo excessive tension, thus facilitating thread crossings.

[0094] At the end of this third sub-step, the fifth layer of warp threads to be taken out 215 is arranged below the reference path Ti30 of the lance 130 while the other layers of warp threads to be woven or taken out are arranged above the reference path Ti30 of the lance 130. Thus, the third and fourth layers of warp threads taken out 213 and 214 in the previous weft column N are also arranged below the reference path Ti30 of the lance 130, while the first and second layers of warp threads taken out 211 and 212 in the previous weft column N are arranged above the reference path Ti30 of the lance 130. A free lance stroke 130 is then carried out in accordance with the fourth sub-step.

[0095] In the example illustrated in Figures 4 to 11, only one layer of warp threads is removed through the lower layer of warp threads 210b in the second weft column N+1 of the transition portion 202 to be produced. It is of course not outside the scope of the invention if several layers of warp threads are removed through the lower layer of warp threads in a weft column of the transition portion to be produced. It is also not outside the scope of the invention if the layer of warp threads to be removed does not correspond to a complete layer of warp threads in the loom.

[0096] The third and fourth sub-steps can be carried out for each layer of warp threads to be brought out through the lower warp thread layer. The third and fourth substeps can also be carried out only for a part of the warp thread layers brought out through the lower warp thread layer.

[0097] Preferably, as illustrated in Figures 4 to 11, when the last rapier stroke 130 of a weft column N has been made in the lowest layers of warp threads in the vertical direction Dv, the first rapier stroke 130 is also made in the following weft column N+1 in the lowest layers of warp threads in the vertical direction Dv. Similarly, when the last rapier stroke 130 of a weft column has been made in the highest layers of warp threads in the vertical direction, the first rapier stroke 130 is also made in the following weft column in the highest layers of warp threads in the vertical direction Dv. This limits the massive displacements of layers of warp threads in the harness and consequently reduces the friction and stresses on the control threads 121.

[0098] As the transition portion 202 is woven, more and more yarns 211 to 216 are brought out through the upper 210h and lower 210b surface warp yarn layers, and must be kept away from the yarns being woven. Thus, the greater the number of layers of brought out yarns 211 to 216, the more it is necessary to enlarge the amplitude of the shed opening, in order to properly position the brought out yarns relative to the yarns to be woven. This avoids crossings between the yarns to be woven and the brought out yarns, thereby reducing friction and the risk of defects. Increasing the angle of the shed opening is achieved by keeping the eyelets through which the brought out yarns pass in a very high or very low position in the harness.The increase in the shed opening is particularly significant when the number of layers of yarns exiting through one of the upper or lower surface layers is greater than four. Indeed, when the number of layers of yarns exiting through one of the upper or lower surface layers is, for example, greater than four, the friction between the yarns increases greatly if the shed opening is not adjusted.

[0099] According to a particular embodiment of the invention, it is possible to bind the warp threads that have come out. Thus, when producing the weft columns N and N+1 of the transition portion 202 of the texture 200, one or more available weft threads 220 can be used in the weft column N or N+1 of the transition portion 202 in order to bind the warp threads that have come out using the empty lance strokes in said weft column N or N+1.

[0100] The woven texture 200 obtained by the method of the invention may correspond to a swollen texture, which will be compacted to obtain a compacted texture with dimensions chosen and adapted to the use which will be made of said texture.

[0101] Thus, it is preferable to have a sufficient spacing between the lower guide bar 171 and the upper guide bar 172 of the guide device 170 so as not to deform the expanded texture 200, and to ensure that the texture will be correctly positioned in the correct vertical position during weaving in order to facilitate the crossing between the warp threads to be taken out and the layers of surface warp threads. Consequently, preferably, during the weaving method according to the invention, the spacing between the lower guide bar 171 and the upper guide bar 172 of the guide device 170 must always be greater than a minimum value Hi70 determined along the vertical direction Dv, as illustrated in FIGS. 4 to 9. This minimum value Hi70 of spacing of the guide bars 171 and 172 preferably corresponds to the product of the desired thickness for the compacted texture by 1.45.In fact, it is estimated that the desired thickness for the compacted texture corresponds to approximately 40% of the 200 expanded texture present on the loom.

[0102] In particular, it may be desired that the compacted texture obtained has a volume rate of threads of at least 58%. Thus, the minimum value Hi70 of spacing of the guide bars 171 and 172 is preferably calculated in the following manner, where E58% is the desired thickness for the compacted preform with a fiber volume rate of 58%:

[0103] / / _ ; xO.58 ^170- Ô4Ô

[0104] Furthermore, the production of warp thread outlets through the surface layers and the correct production of the free lance strokes require large height differences between the eyelets. The large amplitudes between the lowest and highest eyelets in the harness during warp thread outlets or during free lance strokes can create significant tensions if the spacing between the guide bars 171 and 172 remains fixed. Thus, preferably, when producing many warp thread outlets or a free lance stroke, the spacing between the guide bars 171 and 172 can be increased by a certain value to facilitate the warp thread crossings and thus the warp thread outlets. Thus, the guide bars 171 and 172 can be movable relative to each other in the vertical direction Dv.

[0105] According to a particular embodiment of the invention, the spacing of the guide bars is adjusted during each lance stroke, including during empty lance strokes. Thus, the spacing of the guide bars is adjusted each time the lance passes through the loom.

[0106] When weaving a weft column, when making free lance strokes to remove layers of warp yarns through the upper surface warp yarn layer, the spacing between the guide bars is increased for each empty lance stroke. Thus, the value of the spacing of the guide bars 171 and 172 is Hpo + hi in the vertical direction Dv during the first empty lance stroke, hi being a positive height, as illustrated in [Fig.4]. The value of the spacing of the guide bars 171 and 172 is then Hi70 + hi + h2 in the vertical direction Dv during the second empty lance stroke, h2 being a positive height, as illustrated in [Fig.5].

[0107] Preferably, in order to further facilitate yarn crossings, the increase in the spacing of the guide bars when removing one or more layers of warp yarns through the upper surface warp yarn layer is carried out while the lower guide bar is fixed. Thus, only the upper guide bar, which is closest to the upper surface warp yarn layer, is movable to allow the increase in the spacing between the guide bars when removing one or more layers of warp yarns through the upper surface warp yarn layer.

[0108] When the idle rapier strokes for removing layers of warp yarns through the upper surface warp yarn layer are completed and the insertion of the weft yarns begins, the spacing between the guide bars is decreased for each rapier stroke carrying a weft yarn. Thus, the spacing value of the guide bars 171 and 172 is Hi70 + hi + h2 - h3 in the vertical direction Dv when inserting the first weft yarn, h3 being positive, as illustrated in [Fig. 6]. The spacing value of the guide bars 171 and 172 is then Hi70 + hi + h2 - h3 - h4 in the vertical direction Dv when inserting the second weft yarn, h4 being positive, as illustrated in [Fig. 7].

[0109] The value of the spacing between the guide bars can be reduced until the minimum value Hi70 is obtained. Preferably, the reduction in the spacing of the guide bars until the minimum value Hi70 is obtained is carried out while the upper guide bar is fixed. Thus, only the lower guide bar is movable to allow the reduction in the spacing between the guide bars until the minimum value Hi70 is reached.

[0110] Preferably, if n free lance strokes are made to remove one or more layers of warp threads through the upper surface warp thread layer, the minimum spacing value Hi70 is found during the nth insertion of the weft thread. In the example illustrated in Figures 4 to 7, hi = h2 = h3= h4: the minimum spacing value Hi70 is therefore found during the insertion of the second weft thread.

[0111] When continuing the insertion of weft threads after having reached the minimum spacing value Hi70 between the guide bars, the spacing of the guide bars is maintained at said minimum spacing value Hi70 for the insertions following weft threads. In order to avoid tensions in the threads as described above, the value of the spacing of the guide bars is maintained while said guide bars are movable in the vertical direction Dv to adapt to the successive shed openings.

[0112] When making idle lance strokes to remove layers of warp yarns through the lower surface warp yarn layer, the spacing between the guide bars can be increased again during the last weft yarn insertion(s) before the idle lance strokes. Preferably, if making m idle lance strokes to remove one or more layers of warp yarns through the lower surface warp yarn layer, the spacing value of the guide bars is increased for the last m weft yarn insertions.

[0113] Thus, the spacing value of the guide bars 171 and 172 is Hi70 + h5 along the vertical direction Dv during the penultimate insertion of a weft thread, h5 being a positive height, as illustrated in [Fig.8]. The spacing value of the guide bars 171 and 172 is then Hi70 + h5 + h6 along the vertical direction Dv during the last insertion of a weft thread, h6 being a positive height, as illustrated in [Fig.9].

[0114] Preferably, the re-increase of the spacing of the guide bars for the last insertion(s) of weft threads is carried out while the lower guide bar is fixed. Thus, only the upper guide bar is movable to allow the re-increase of the spacing between the guide bars.

[0115] When performing the vacuum lance stroke(s) to remove layers of warp yarns through the lower surface warp yarn layer, the spacing between the guide bars is decreased for each vacuum lance stroke (not shown).

[0116] The value of the spacing between the guide bars can be reduced until the minimum value Hi70 is obtained for the last empty lance stroke. Preferably, the reduction in the spacing of the guide bars until the minimum value Hi70 is obtained is carried out while the upper guide bar is fixed. Thus, only the lower guide bar is movable to allow the reduction in the spacing between the guide bars until the minimum value Hi70 is reached.

[0117] Thus, within the framework of the method of the invention, the first portion 201 of the texture 200 is woven during the first step and the transition portion 202 of the texture 200 is woven during the second step.

[0118] In the second step, for each weft column of the transition portion 202 to be produced and if it is desired to remove warp threads through the upper surface layer 210h, the first and second sub-steps are carried out for each set of warp threads to be removed through the upper surface layer 210h. In effect, the first sub-step allows the warp threads to be properly arranged on either side of the reference path, creating the desired shed, and the second sub-step corresponds to an empty lance stroke.

[0119] During the second step, for each weft column of the transition portion 202 to be produced and if it is desired to remove warp threads through the lower surface layer 210b, the third and fourth sub-steps are carried out for each set of warp threads to be removed through the lower surface layer 210b. Indeed, the third sub-step makes it possible to properly arrange the warp threads on either side of the reference path by producing the desired shed, and the fourth sub-step corresponds to an empty lance stroke.

[0120] In the example described above, for reasons of simplification, the output of the warp threads by entire layer is described in one go. However, in practice, a layer of warp threads is generally output in at least two goes, or only a part of the layer of warp threads is output. For example, to output an entire layer of warp threads, one first outputs a part of said layer by making one stroke of the lance while empty, then the other part of said layer is output by making another stroke of the lance while empty.

[0121] In the example illustrated in Figures 3 to 11, the layers of surface warp yarns are continuous and made up of the same warp yarns along the entire length of the texture. However, it does not depart from the scope of the invention if the layers of surface warp yarns are made up of different warp yarns along the length of the texture.

[0122] The warp and weft yarns used in the present invention 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.

[0123] The woven texture can thus be intended to form the fibrous 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 fibrous 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 the performance of aircraft, in particular by improving the efficiency of the turbomachine and by reducing the overall mass of the engine, thus significantly reducing emissions harmful to the environment.

Claims

Claims

1. Method for three-dimensional weaving of a texture (200) between a plurality of layers of warp threads (210) superimposed in a vertical direction (Dv) and a plurality of weft threads (220) extending in a horizontal direction (DH), the weaving being carried out by means of a loom (100) comprising a plurality of control threads (121), a first end of each control thread (121) being connected to a Jacquard mechanism (110) capable of moving the control threads (121) in the vertical direction (Dv) between a neutral position and at least one position for opening the warp threads (210), each control thread (121) being further provided with an eyelet (121a) crossed by a warp thread (110),the weaving loom (100) further comprising at least one lance (130) having downstream control threads (121) capable of passing through the weaving loom (100) along a fixed horizontal reference path (Tno) and of drawing a weft thread (220) from a bobbin (140), characterized in that the method further comprises at least one step of outputting warp threads comprising:, - the displacement in the vertical direction (Dv) of all or part of the warp threads of at least one underlying layer of warp threads (211, 212, 213, 214, 215, 216) of the plurality of layers of warp threads, said displaced warp threads (211) being intended to be taken out of the texture (200), over a determined distance extending beyond a layer of warp threads (210h; 210b) present on the surface of the plurality of layers of warp threads (210), so that the displaced warp thread(s) (211) are arranged above the reference path (Tno) and the remainder of the non-exited warp threads are arranged below the reference path (Ti30), or so that the displaced warp thread(s) (211) are arranged below the reference path (Tno) and the remainder of the non-exited warp threads are arranged below the reference path (Ti30), output is placed above the reference path (Tno), then - the crossing of the loom (100) by the lance (130) according to the reference path (Tno) without pulling any weft thread.

2. Method according to claim 1, wherein when weaving at least one weft column (N; N+1) a plurality of underlying warp yarn layers (211, 212; 213, 214; 215; 216) is intended to be taken out of the texture (200) beyond one of the warp yarn layers

3.

4. (210h, 210b) present on the surface of the plurality of layers of warp threads (210), the following step of exiting warp threads being repeated for each layer of warp threads to be exited (211, 212; 213, 214; 215; 216) beyond said layer (21 Oh, 210b) present on the surface: the displacement in the vertical direction (Dv) of the layer of warp threads to be exited (211, 212, 213, 214, 215, 216) over a determined distance extending beyond the layer of warp threads present on the surface (210h, 210b) of the plurality of layers of warp threads (210), so that the displaced layer of warp threads (211, 212, 213, 214, 215, 216) is arranged above the path reference path (Tno) and below the previously displaced layers of warp threads intended to be output from the texture (200) and that the remainder of the un-outputted warp threads are arranged below the reference path (Tno), or so that the displaced layer of warp threads (211,212, 213,214, 215,216) is arranged below the reference path (Tno) and above the layers of warp threads previously moved to be taken out of the texture (200) and the rest of the warp threads not taken out are arranged above the reference path (Tno); then the crossing of the loom (100) by the rapier (130) along the reference path (Tno) without pulling any weft thread., Method according to claim 1 or 2, in which the step of taking out warp threads further comprises, after the lance (130) has passed through the loom (100) without drawing any weft thread: - the movement in the vertical direction (Dv) of a part of the displaced warp threads or of a part of the displaced layer so that said part of the displaced warp threads or of the displaced layer is arranged below the reference path (Tno) and that the other part of the displaced warp threads or of the displaced layer of yarn is arranged above the reference path (Tno), then - the crossing of the loom by the lance along the reference path (T 130) by pulling a weft thread (220) so as to bind together the displaced warp threads. A method according to any one of claims 1 to 3, wherein the loom (100) further comprises a guide device (170) present downstream of the plurality of control threads (121) and the rapier (130), the guide device (170) being able to move in the vertical direction (Dv) so as to move the woven texture (200) upwards or downwards relative to a horizontal reference plane (PH). including the reference path (Tno).

5. Method according to claim 4, wherein the guide device (170) comprises an upper guide bar (172) and a lower guide bar (171) configured to be positioned in contact with the woven texture (200) and on either side of said texture (200) in the vertical direction (Dv), the minimum value of the spacing between the guide bars (171, 172) corresponding to the thickness of the uncompacted woven texture (200).

6. Method according to claim 5, in which the spacing between the guide bars (171, 172) increases during the movement in the vertical direction (Dv) of all or part of the warp threads (211, 212, 213, 214, 215, 216) intended to be taken out of the texture (200) over a determined distance extending beyond a layer of warp threads present on the surface (210b, 210h) of the plurality of layers of warp threads (210).

7. Method according to claim 5 or 6, wherein the guide bars (171, 172) of the guide device (170) are configured to move in the vertical direction (Dv) as a function of the vertical position of the eyelets (121a) of the harness (120) during the movement in the vertical direction (Dv) of all or part of the warp threads (211, 212, 213, 214, 215, 216) intended to be taken out of the texture (200) over a determined distance extending beyond a layer of warp threads present on the surface (210h, 210b) of the plurality of layers of warp threads (210), so that in each plane of the loom (100) perpendicular to the reference path (Tno),the length between the harness (120) and the woven texture (200) of the lowest warp yarn located above the reference path (Tno) corresponds to between 90% and 110% of the length between the harness (120) and the woven texture (200) of the highest warp yarn located below the reference path (Tno).,

8. Method according to any one of claims 4 to 7, the guide device (170) being configured to move between a first position and a second position in the vertical direction (Dv) as a function of the vertical position of the eyelets (121a) of the harness (121) after the movement in the vertical direction (Dv) of all or part of the warp threads (211, 212, 213, 214, 215, 216) intended to be taken out of the texture (200) over a determined distance extending beyond a layer of warp threads (210h, 210b) present on the surface of the plurality of layers of warp threads (210), so that in each plane of the loom (100) perpendicular to the reference path (Tno), the length between the harness (120) and the woven texture (200) of the highest warp thread located below the reference path (Tno) when the guide device (170) is in the first position is between 90% and 110% of the length between the harness (120) and the woven texture (200) of said warp thread when it is the lowest located above the reference path (Tno) when the guide device (170) is in the second position.

9. A method according to any one of claims 1 to 8, wherein the warp (210) and weft (220) yarns are carbon, glass or ceramic fibers.

10. Method according to any one of claims 1 to 9, in which the woven texture (200) is intended to form a fibrous reinforcement for a composite material part of an aeronautical engine.

Images