Patent Publication Number: US-2021180221-A1

Title: Fiber construct, fiber-reinforced composite material, and method for manufacturing these

Description:
TECHNICAL FIELD 
     The present disclosure relates to a fiber construct and a fiber-reinforced composite material. 
     BACKGROUND ART 
     Fiber-reinforced composite materials are widely used as lightweight structural materials. A reinforced base material for a fiber-reinforced composite material includes a fiber construct. The fiber-reinforced composite material formed to be a matrix by impregnating the fiber construct with resin is used as a structural material for, for example, airplanes, automobiles, and buildings. In some fiber constructs, fiber layers are laminated, and binding threads are used to bind the fiber layers are bound in the laminating direction. 
     To make the fiber-reinforced composite material usable for a wide variety of purposes, a fiber-reinforced composite material needs to be shaped in accordance with the purposes such as an L-shaped or U-shaped fiber-reinforced composite material. For example, to manufacture the L-shaped or U-shaped fiber-reinforced composite material, its fiber construct also needs to be L-shaped or U-shaped. Such a fiber construct includes a bent portion. 
       FIG. 9  shows a three-dimensional fiber construct  90 , which is described as an example in Japanese Laid-Open Patent Publication No. 2007-291582 (Patent Document 1). The three-dimensional fiber construct  90  includes laminated fiber layers  91  and thickness direction threads  92 . The laminated fiber layers  91  are laid out such that continuous fibers are biaxially oriented. The thickness direction threads  92  bind the fiber layers of the laminated fiber layers  91  in the thickness direction. Further, the laminated fiber layer  91  has a three-dimensional plate shape such that bent portions  94   a  and  94   b  bent in different directions and flat portions  95   a ,  95   b , and  95   c  are alternately laid out and continuous with one another. 
     The continuous fibers used for the three-dimensional fiber construct  90  are generally very small. This prevents the continuous fibers laid out on the outer sides of the bends from stretching. This may generate creases on the inner sides of the bent portions  94   a  and  94   b . In the fiber-reinforced composite material having the three-dimensional fiber construct  90 , creases will cause degradation of the physical properties (for example, degradation of strength) and lower the appearance quality. 
     In the document, a single bent portion  94   a  is located between a pair of flat portions  95   a  and  95   b . In one of the flat portions, namely, the flat portion  95   b , the thickness direction threads  92  are laid out to diagonally intersect the fiber layers. In the other one of the flat portions, namely, the flat portion  95   a , the thickness direction threads  92  are laid out to be orthogonal to the fiber layers. 
     In the document, during bending of the laminated fiber layer  91 , bending and compressing the laminated fiber layer  91  in the thickness direction attempt to deviate non-bent portions of the continuous fibers laid out on the outer sides of the bent portions  94   a  and  94   b . When the continuous fibers and the thickness direction threads  92 , which are laid out in the non-bent portions, move such that the deviation is tolerated, the generation of creases is limited in the bent portions  94   a  and  94   b.    
     PRIOR ART DOCUMENTS 
     Patent Documents 
     Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-291582 
     SUMMARY OF THE INVENTION 
     Problems that the Invention is to Solve 
     However, in order to limit the generation of creases in the bent portions  94   a  and  94   b , the three-dimensional fiber construct  90  described in the document needs to be structured so as to tolerate deviation of the thickness direction threads  92 . To tolerate the deviation of the thickness direction threads  92 , the laminated fiber layers  91  need to be compressed in the thickness direction during bending. This manufacturing process is troublesome. 
     It is an objective of the present disclosure to provide a fiber construct and a fiber-reinforced composite material that can be easily manufactured while limiting the generation of creases in bent portions. 
     Means for Solving the Problem 
     A fiber construct that solves the above-described problem includes first fiber layers including a first yam and second fiber layers including a second yarn that intersects the first yarn, wherein the first fiber layers and the second fiber layers are laminated, wherein an extending direction of a yam main axis of the first yam is referred to as a first direction, and an extending direction of a yam main axis of the second yarn is referred to as a second direction, wherein the fiber construct has a plate shape such that at least a first flat portion, a bent portion, and a second flat portion are continuous with one another in the second direction, wherein a direction in which the first fiber layers and the second fiber layers are laminated is referred to as a laminating direction, wherein in the first flat portion, the first yam extends straight in the first direction and the second yarn extends straight in the second direction, wherein the fiber construct further includes a binding thread that binds all the first fiber layers and the second fiber layers in the laminating direction in the first flat portion, wherein the binding thread is configured to be in any one of a mode of extending straight in the bent portion and the second flat portion, a mode of binding the first fiber layers and the second fiber layers partially in the laminating direction in the bent portion and the second flat portion, and a mode of being absent in the bent portion and the second flat portion, wherein in the bent portion and the second flat portion, the second yarn is configured to be in any one of a mode of engaging with only the first yarn of a specific one of the first fiber layers and a mode of binding the first fiber layers partially in the laminating direction. 
     In this structure, in the first flat portion, the binding threads prevent the first fiber layers and the second fiber layers from being scattered. 
     More specifically, in the first flat portion, the binding threads bind all the first fiber layers and the second fiber layers. In the bent portion and the second flat portion, the binding threads do not bind all the first fiber layers and the second fiber layers in the laminating direction, and the second yarns do not bind all the first fiber layers and the second fiber layers in the laminating direction. Thus, on the inner side of the bent portion, the movement of the first yarns and the second yarns caused by bending is allowed. This limits, for example, situations in which the second yarns are bent and the first yarns are put together to be laminated in multi-stages. Accordingly, the generation of creases on the inner sides of the bent portion is limited. The fiber construct having the above-described structure is formed by controlling the binding threads when weaving is performed by a loom. Thus, for example, the fiber construct does not have to be compressed in order to limit the generation of creases in the bent portion. Accordingly, the fiber construct can be manufactured easily. 
     Further, in the fiber construct, in the first flat portion, the first fiber layer may be arranged between a pair of the second fiber layers adjacent to each other in the laminating direction, and in the bent portion and the second flat portion, the second yarn of the pair of the second fiber layers adjacent to each other in the laminating direction with the specific one of the first fiber layers located in between may be in a mode of engaging with each one of the first yarns of the specific one of the first fiber layers alternately from opposite sides in the laminating direction. 
     In this structure, in the bent portion and the second flat portion, the second yarns are engaged with only the first yarns of a specific one of the first fiber layers from the opposite sides in the laminating direction. Thus, the first yarns and the second yarns are engaged with each other. This prevents the first fiber layers and the second fiber layers from being scattered. 
     Further, in the fiber construct, in the first flat portion, a first laminate and a second laminate may be laid out in the laminating direction, the first laminate may be formed by arranging a pair of the second fiber layers between a pair of the first fiber layers adjacent to each other in the laminating direction, the second laminate may be formed by arranging a pair of the second fiber layers between a pair of the first fiber layers adjacent to each other in the laminating direction, and in the bent portion and the second flat portion, in the first laminate and the second laminate, the pair of the second fiber layers arranged between the first fiber layers adjacent to each other in the laminating direction may include the second yarns, a part of the second yarns being in a mode of engaging with the first yarn of the first fiber layers so that the pair of the first fiber layers adjacent to each other in the laminating direction are bound to each other partially in the laminating direction, and a part of the second yarns of one of the laminates of the first laminate and the second laminate may be in a mode of engaging with the first yarn of the other one of the laminates of the first laminate and the second laminate so that the first laminate and the second laminate are bonded to each other in the laminating direction. 
     In this structure, in the bent portion and the second flat portion, in the first laminate and the second laminate, the first fiber layers adjacent to each other in the laminating direction are bound by the second yarns partially in the laminating direction. Further, the first laminate and the second laminate are bonded to each other in the laminating direction. This prevents the bent portion and the second flat portion from being scattered in the laminating direction. 
     Further, in the above-described fiber construct, a dimension of the fiber construct extending through an inner side of the bent portion in the second direction may be substantially the same as a dimension of the fiber construct extending through an outer side of the bent portion in the second direction. 
     A fiber-reinforced composite material that solves the above-described problem is formed by impregnating a reinforcing base material with matrix resin, characterized in that the reinforcing base material is formed by the above-described fiber construct. 
     In this structure, in the first flat portion, the binding threads prevent the first fiber layers and the second fiber layers from being scattered 
     More specifically, in the first flat portion, the binding threads bind all the first fiber layers and the second fiber layers. In the bent portion and the second flat portion, the binding threads do not bind all the first fiber layers and the second fiber layers, and the second yarns do not bind all the first fiber layers and the second fiber layers. Thus, on the inner side of the bent portion, the movement of the first yarns and the second yarns caused by bending is allowed. This limits, for example, situations in which the second yarns are bent and the first yarns are put together to be laminated in multi-stages. Accordingly, the generation of creases on the inner sides of the bent portion is limited. The fiber construct having the above-described structure is formed by controlling the binding threads when weaving is performed by a loom. Thus, for example, the fiber construct does not have to be compressed in order to limit the generation of creases in the bent portion. Accordingly, the fiber construct can be manufactured easily. In the fiber-reinforced composite material with the fiber construct used as a reinforcing base material, the part corresponding to the bent portion of the fiber construct is prevented from being lowered in strength by creases. 
     A manufacturing method for the above-described fiber construct is provided as another aspect of above-described disclosure. That is, the manufacturing method includes preparing first fiber layers including a first yarn, preparing second fiber layers including a second yarn that intersects the first yarn, laminating the first fiber layers and the second fiber layers with an extending direction of a yarn main axis of the first yarn referred to as a first direction and an extending direction of a yarn main axis of the second yarn referred to as a second direction, a direction in which the first fiber layers and the second fiber layers are laminated being referred to as a laminating direction, shaping the fiber construct into a plate such that at least a first flat portion, a bent portion, and a second flat portion are continuous with one another in the second direction, extending the first yarn straight in the first direction and extending the second yarn straight in the second direction in the first flat portion, binding all the first fiber layers and the second fiber layers in the laminating direction in the first flat portion using a binding thread, configuring the binding thread to be in any one of (a) a mode of extending straight in the bent portion and the second flat portion, (b) a mode of binding the first fiber layers and the second fiber layers partially in the laminating direction in the bent portion and the second flat portion, and (c) a mode of being absent in the bent portion and the second flat portion, and configuring, in the bent portion and the second flat portion, the second yarn to be in any one of a mode of engaging with only the first yarn of a specific one of the first fiber layers and a mode of binding the first fiber layers partially in the laminating direction. 
     In the present disclosure, a fiber construct and a fiber-reinforced composite material can be easily manufactured while limiting the generation of creases in bent portions 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view schematically showing a fiber-reinforced composite material according to a first embodiment of the present disclosure. 
         FIG. 2  is a schematic cross-sectional view showing the fiber construct prior to being shaped in the first embodiment. 
         FIG. 3  is a schematic cross-sectional view showing the fiber construct of  FIG. 2  subsequent to being shaped. 
         FIG. 4  is a schematic cross-sectional view showing the fiber construct prior to being shaped according to a second embodiment of the present disclosure. 
         FIG. 5  is a schematic cross-sectional view showing the fiber construct of  FIG. 4  subsequent to being shaped. 
         FIG. 6  is a side view schematically showing the fiber construct according to a modification of the present disclosure. 
         FIG. 7  is a schematic cross-sectional view showing the fiber construct according to a modification of the first embodiment. 
         FIG. 8  is a schematic cross-sectional view showing the fiber construct according to a modification of the second embodiment. 
         FIG. 9  is a diagram showing the related art. 
     
    
    
     MODES FOR CARRYING OUT THE INVENTION 
     First Embodiment 
     A fiber construct and a fiber-reinforced composite material according to a first embodiment of the present disclosure will now be described with reference to  FIGS. 1 to 3 . 
     Referring to  FIG. 1 , a fiber-reinforced composite material  10  is formed by impregnating a fiber construct  11 , which serves as a reinforcing base material, with matrix resin  12 . For example, thermosetting epoxy resin is used for the matrix resin  12 . The fiber construct  11  is formed by shaping a flat fiber construct  11  into an L-shape. The fiber construct  11  includes a first flat portion  16 , a second flat portion  17 , and a bent portion  18  located between the first flat portion  16  and the second flat portion  17 . The fiber construct  11  has a three-dimensional plate shape such that the first flat portion  16 , the bent portion  18 , and the second flat portion  17  are continuous with one another in sequence. 
     The fiber construct  11  in a flat state prior to being shaped will now be described. 
     While  FIG. 2  shows the fiber construct  11  prior to being shaped,  FIG. 1  shows the fiber construct  11  subsequent to being shaped into an L-shape. In  FIG. 1 , only the first flat portion  16  can be referred to as a state prior to being shaped. 
     As shown in  FIGS. 1 and 2 , the fiber construct  11  is formed by laminating fiber layers. The direction in which the fiber layers are laminated is referred to as a laminating direction Y of the fiber construct  11 . In  FIGS. 1 and 2 , the double-headed arrow indicating the laminating direction Y indicates the laminating direction Y of the first flat portion  16 . The fiber construct  11  includes weft yarns  13 , which serve as first yarns, and warp yarns  14 , which serve as second yarns. The fiber construct  11  also includes binding threads  15  that bind the fiber layers in the laminating direction Y. 
     In the fiber construct  11 , the weft yarns  13  and the warp yarns  14  extend in directions that intersect with each other. The extending direction of a yarn main axis of the weft yarns  13  is referred to as a first direction X 1 , and the extending direction of a yarn main axis of the warp yarns  14  is referred to as a second direction X 2 . In  FIG. 1 , the double-headed arrows indicating the first direction X 1  and the second direction X 2  indicate the first direction X 1  and the second direction X 2  of the first flat portion  16 , respectively. The weft yarns  13 , the warp yarns  14 , and the binding threads  15  are fiber bundles that are formed by binding fibers. The fibers may be organic fibers or inorganic fibers. The organic fibers include, for example, aramid fibers, poly-p-phenylene benzobisoxazole fibers, and ultra-high molecular weight polyethylene fibers. The inorganic fibers include, for example, carbon fibers, glass fibers, and ceramic fibers. 
     The fiber construct  11  includes weft yam layers, which serve as fiber layers formed by laying out the weft yarns  13  in the second direction X 2 . All the weft yarns  13  extend substantially straight in the first direction X 1  and do not engage with the warp yams  14  through folding. As shown in  FIG. 2 , the weft yarn layers include a first weft yam layer  21 , a second weft yam layer  22  adjacent to the first weft yarn layer  21  in the laminating direction Y, a third weft yam layer  23  adjacent to the second weft yarn layer  22  in the laminating direction Y, and a fourth weft yam layer  24  adjacent to the third weft yam layer  23  in the laminating direction Y. That is, the first weft yam layer  21  to the fourth weft yarn layer  24  are first fiber layers each including the weft yarn  13 , which serves as the first yarn.  FIG. 2  shows the fiber construct  11  in the cross-section perpendicular to the first direction X 1  (i.e., plane parallel to second direction X 2  and laminating direction Y). Thus,  FIG. 2  shows the cross-sections of the first to fourth weft yam layers  21  to  24  and the weft yams  13 . 
     Further, the fiber construct  11  includes warp yarn layers, which are formed by laying out the warp yams  14  in the first direction X 1 . As shown in  FIG. 2 , the fiber construct  11  includes, as the warp yam layers, a first warp yam layer  31  and a second warp yarn layer  32  on the opposite sides of the first weft yarn layer  21  in the laminating direction Y and a third warp yam layer  33  and a fourth warp yarn layer  34  on the opposite sides of the second weft yam layer  22  in the laminating direction Y. Further, the fiber construct  11  includes, as the warp yam layers, a fifth warp yam layer  35  and a sixth warp yam layer  36  on the opposite sides of the third weft yam layer  23  in the laminating direction Y and a seventh warp yam layer  37  and a eighth warp yam layer  38  on the opposite sides of the fourth weft yarn layer  24  in the laminating direction Y. That is, the first warp yam layer  31  to the eighth warp yam layer  38  are second fiber layers each including the warp yarn  14 , which serves as the second yarn. 
     The fiber construct  11  in the L-shaped state will now be described. 
     Referring to  FIGS. 1 and 3 , the bent portion  18  of the fiber construct  11  is bent around the axis extending in the first direction X 1 . In  FIGS. 1 and 3 , the fiber construct  11  is L-shaped. Thus, the laminating direction Y of the second flat portion  17  subsequent to being shaped is substantially parallel to the second direction X 2  of the first flat portion  16  (horizontal direction on the plane), and the second direction X 2  of the second flat portion  17  subsequent to being shaped is substantially parallel to the laminating direction Y of the first flat portion  16  (vertical direction on the plane). Thus, in the fiber construct  11 , the first flat portion  16 , the bent portion  18 , and the second flat portion  17  are made continuous with one another in sequence in the second direction X 2  by the warp yams  14 . In the first flat portion  16 , the weft yams  13  are laid out in the second direction X 2 , and each weft yarn  13  extends straight in the first direction X 1 . Additionally, in the first flat portion  16 , each warp yarn  14  extends straight in the second direction X 2 . 
     As shown in  FIG. 3 , in the bent portion  18 , the weft yarns  13  are laid out along the arc of the bent portion  18 . Further, in the bent portion  18 , each warp yarn  14  extends so as to wave in the laminating direction Y microscopically and extends along the arc of the bent portion  18  macroscopically. In the second flat portion  17 , the weft yarns  13  are laid out in the extending direction of the warp yams  14  (second direction X 2 ). Further, in the second flat portion  17 , instead of extending straight, each warp yarn  14  extends so as to wave in the laminating direction Y microscopically and extends in the second direction X 2  macroscopically. 
     As both shown in  FIGS. 2 and 3 , in the first flat portion  16 , the first to fourth weft yam layers  21  to  24  and the first to eighth warp yam layers  31  to  38  are bound by the binding threads  15  in the laminating direction Y. More specifically, in the first flat portion  16 , all the first to fourth weft yarn layers  21  to  24  and the first to eighth warp yarn layers  31  to  38  are bound by the binding threads  15  in the laminating direction Y. 
     As both shown in  FIGS. 2 and 3 , in the first flat portion  16 , the warp yams  14  of the first to eighth warp yam layers  31  to  38  extend straight in the second direction X 2 . Further, the first weft yarn layer  21  is arranged between the first warp yarn layer  31  and the second warp yarn layer  32  adjacent to each other in the laminating direction Y, and the warp yarns  14  of the first warp yam layer  31  and the second warp yarn layer  32 , with the first weft yam layer  21  located in between in the laminating direction Y, are parallel to each other. In the same manner, the second weft yam layer  22  is arranged between the third warp yam layer  33  and the fourth warp yam layer  34  adjacent to each other in the laminating direction Y, and the warp yams  14  of the third warp yarn layer  33  and the fourth warp yam layer  34 , with the second weft yam layer  22  located in between in the laminating direction Y, are parallel to each other. In the same manner, the third weft yam layer  23  is arranged between the fifth warp yarn layer  35  and the sixth warp yam layer  36  adjacent to each other in the laminating direction Y, and the warp yams  14  of the fifth warp yam layer  35  and the sixth warp yam layer  36 , with the third weft yarn layer  23  located in between in the laminating direction Y, are parallel to each other. In the same manner, the fourth weft yam layer  24  is arranged between the seventh warp yam layer  37  and the eighth warp yarn layer  38  adjacent to each other in the laminating direction Y, and the warp yams  14  of the seventh warp yam layer  37  and the eighth warp yam layer  38 , with the fourth weft yam layer  24  located in between in the laminating direction Y, are parallel to each other. 
     The binding threads  15  are used to keep the shape of the first flat portion  16 . The mode of folding the binding threads  15  will now be described. The binding threads  15  are arranged so as to be laid out partially in parallel to the warp yams  14  and folded through the outer surfaces of the weft yams  13  of the first weft yam layer  21 , which is the uppermost layer of the first flat portion  16 . Further, the binding threads  15  are arranged so as to be extended straight through the first flat portion  16  in the laminating direction Y and folded through the outer surface of the weft yarns  13  of the fourth weft yam layer  24 , which is the lowermost layer. That is, the binding threads  15  bind the weft yarns  13  and the warp yarns  14  in the laminating direction Y by repeatedly being folded so as to entangle the surroundings of the cross-sections of the weft yarns  13  of the first weft yam layer  21  from the outer side of the fiber construct  11  (upper side in  FIG. 2 ) and being folded so as to entangle the surroundings of the cross-sections of the weft yarns  13  of the fourth weft yarn layer  24  from the outer side of the fiber construct  11  (lower side in  FIG. 2 ). 
     In  FIGS. 2 and 3 , the first direction X 1  is perpendicular to the plane. In the binding threads  15  adjacent to each other in the first direction X 1 , the position of the weft yam  13  corresponding to the binding thread  15  folded at the first weft yarn layer  21  or the fourth weft yam layer  24  is deviated in the second direction X 2 . For example, in the binding threads  15  adjacent to each other in the direction perpendicular to the planes of  FIGS. 2 and 3 , the position of the weft yarn  13  corresponding to a part where the front binding thread  15  is folded at the first weft yarn layer  21  and the position of the weft yam  13  corresponding to a part where the rear binding thread  15  is folded at the first weft yam layer  21  are deviated in the second direction X 2 . Further, all the first to fourth weft yam layers  21  to  24  and the first to eighth warp yarn layers  31  to  38  are bound by the binding threads  15  in the laminating direction Y. 
     The folding positions of the binding thread  15  are located at equal intervals in the second direction X 2 , and the binding threads  15  extend through the first flat portion  16  at equal intervals in the second direction X 2 . In the present embodiment, each binding thread  15  is folded for one weft yam  13 . The binding threads  15  are extended straight through the first flat portion  16  in the laminating direction Y and folded to have parts extending along the weft yarns  13  laid out in the laminating direction Y. This causes the binding threads  15  to restrict the weft yarns  13  from moving in the second direction X 2 . 
     The second flat portion  17  and the bent portion  18  include the first to fourth weft yam layers  21  to  24  and the first to eighth warp yam layers  31  to  38 . In addition, in the second flat portion  17  and the bent portion  18 , movement of the weft yams  13  and warp yams  14  caused by bending is allowed. 
     Thus, as shown in  FIG. 1 , in the fiber construct  11 , the dimension L 1  extending through the inner side of the bent portion  18  in the dimension extending in the second direction X 2  is the same as or just slightly deviates from the dimension L 2  extending through the outer side of the bent portion  18 . That is, the dimension L 1  is substantially the same as the dimension L 2 . In the fiber construct  11  of  FIG. 2  prior to being shaped, the part corresponding to the dimension L 1  has the same length as the part corresponding to the dimension L 2 . 
     As shown in  FIG. 3 , in the bent portion  18  and the second flat portion  17 , the warp yams  14  of the first warp yam layer  31  and the second warp yarn layer  32 , with the first weft yarn layer  21  located in between in the laminating direction Y, are in a mode of being folded on the outer side in the laminating direction Y and engaged with only the weft yarns  13  of the first weft yarn layer  21 , which is a specific one of the first fiber layers. Further, in the bent portion  18  and the second flat portion  17 , the warp yarns  14  of the first warp yarn layer  31  and the second warp yarn layer  32 , with the first weft yarn layer  21  located in between in the laminating direction Y, are in a mode of being folded and engaged on the inner side in the laminating direction Y of the weft yarns  13  adjacent to each other in the second direction X 2 . That is, the warp yarns  14  of the first warp yarn layer  31  and the second warp yarn layer  32  are repeatedly engaged with the weft yarns  13  of the first weft yarn layer  21  alternately from the opposite sides in the laminating direction Y. In this manner, in the present embodiment, the warp yarns  14  of the first warp yarn layer  31  and the second warp yarn layer  32  are not engaged with the weft yarns  13  of the second weft yarn layer  22  to the fourth weft yarn layer  24  and are engaged with only the weft yarns  13  of the first weft yarn layer  21 , which serves as a specific weft yarn layer. Here, the warp yarns  14  of the first warp yarn layer  31  and the second warp yarn layer  32  are classified into two groups, and a focus is made on a single weft yarn  13  of the first weft yarn layer  21 . When the warp yarn  14  of the first group is engaged with the single weft yarn  13  so as to entangle the surroundings of the cross-section of the single weft yarn  13  from one side in the laminating direction Y (for example, outer side of bend), the warp yarn  14  of the second group is engaged with the single weft yarn  13  so as to entangle the surroundings of the cross-section of the single weft yarn  13  from the other side in the laminating direction Y (for example, inner side of bend). In the weft yarn  13  adjacent to the single weft yarn  13  in the second direction X 2 , the warp yarn  14  of the first group is engaged with the adjacent weft yarn  13  so as to entangle the surroundings of the cross-section of the adjacent weft yarn  13  on the other side in the laminating direction Y, and the warp yarn  14  of the second group is engaged with the adjacent weft yarn  13  so as to entangle the surroundings of the cross-section of the adjacent weft yarn  13  on one side in the laminating direction Y. 
     Likewise, the warp yarns  14  of the third warp yarn layer  33  and the fourth warp yarn layer  34 , with the second weft yarn layer  22  located in between in the laminating direction Y, are in a mode of being folded on the outer and inner sides in the laminating direction Y and alternately engaged with only the weft yarns  13  of the second weft yarn layer  22 , which is a specific one of the first fiber layers. That is, the warp yarns  14  of the third warp yarn layer  33  and the fourth warp yarn layer  34  are repeatedly engaged with the weft yarns  13  of the second weft yarn layer  22  alternately from the opposite sides in the laminating direction Y. 
     The warp yarns  14  of the fifth warp yarn layer  35  and the sixth warp yarn layer  36 , with the third weft yarn layer  23  located in between in the laminating direction Y, are in a mode of being folded on the outer and inner sides in the laminating direction Y and alternately engaged with only the weft yarns  13  of the third weft yarn layer  23 , which is a specific one of the first fiber layers. That is, the warp yarns  14  of the fifth warp yarn layer  35  and the sixth warp yarn layer  36  are repeatedly engaged with the weft yarns  13  of the third weft yarn layer  23  alternately from the opposite sides in the laminating direction Y. 
     Furthermore, the warp yarns  14  of the seventh warp yarn layer  37  and the eighth warp yarn layer  38 , with the fourth weft yarn layer  24  located in between in the laminating direction Y, are in a mode of being folded on the outer and inner sides in the laminating direction Y and alternately engaged with only the weft yarns  13  of the fourth weft yarn layer  24 , which is a specific one of the first fiber layers. That is, the warp yarns  14  of the seventh warp yarn layer  37  and the eighth warp yarn layer  38  are repeatedly engaged with the weft yarns  13  of the fourth weft yarn layer  24  alternately from the opposite sides in the laminating direction Y. 
     In the bent portion  18  and the second flat portion  17 , the binding threads  15  are classified into two groups. The first group includes a binding thread  15   a  that is in a mode of being arranged between the first weft yarn layer  21  and the second weft yarn layer  22  in the laminating direction Y and extended straight in the second direction X 2 . Thus, in the bent portion  18  and the second flat portion  17 , the binding thread  15   a  of the first group is not folded along the surroundings of the cross-sections of any weft yarns  13  and not engaged with the weft yarns  13 . That is, in the bent portion  18  and the second flat portion  17 , the binding thread  15  is not folded so as to entangle the surroundings of the cross-sections of the weft yarns  13 . Further, the second group of the two groups of the binding threads  15  includes a binding thread  15   b . In the bent portion  18  and the second flat portion  17 , the binding thread  15   b  is in a mode of being arranged between the third weft yarn layer  23  and the fourth weft yarn layer  24  in the laminating direction Y and extended straight in the second direction X 2 . The binding thread  15   b  is not folded along the surroundings of the cross-sections of any weft yarns  13  and not engaged with the weft yarns  13 . 
     The above-described embodiment has the following advantages. 
     (1-1) In the bent portion  18  and the second flat portion  17  of the fiber construct  11 , the binding threads  15  and the warp yarns  14  do not bind all the first to fourth weft yarn layers  21  to  24  and the first to eighth warp yarn layers  31  to  38  in the laminating direction Y and the second direction X 2 . Thus, in the bent portion  18 , the weft yarns  13  and the warp yarns  14  are allowed to move in the second direction X 2 . This limits, for example, situations in which the warp yarns  14  are bent and the weft yarns  13  are put together to be laminated in multi-stages. Accordingly, the generation of creases on the inner sides of the bent portion  18  is limited. The generation of creases on the inner sides of the bent portion  18  is limited just by controlling the binding threads  15  during weaving of the fiber construct  11 . This allows the fiber construct  11  to be easily manufactured with the generation of creases limited. 
     (1-2) The binding threads  15  bind the weft yarns  13  of the first flat portion  16  in the laminating direction Y and the second direction X 2  and function as warp yarns in the bent portion  18  and the second flat portion  17 . This allows the binding threads  15  to reinforce the bent portion  18  and the second flat portion  17 . 
     (1-3) In the first flat portion  16 , the weft yarns  13  and the warp yarns  14  extend straight, and are bound by the binding threads  15  in the laminating direction Y. Thus, in the first flat portion  16 , the binding threads  15  prevent all the first to fourth weft yarn layers  21  to  24  and the first to eighth warp yarn layers  31  to  38  from being scattered. 
     (1-4) In the fiber construct  11 , the generation of creases on the inner side of the bent portion  18  is limited. Thus, in the fiber-reinforced composite material  10  with the fiber construct  11  used as a reinforcing base material, the part corresponding to the bent portion  18  is prevented from being lowered in strength by creases. 
     (1-5) In the bent portion  18  and the second flat portion  17  of the fiber construct  11 , the binding threads  15  and the warp yarns  14  do not bind all the first to fourth weft yarn layers  21  to  24  and the first to eighth warp yarn layers  31  to  38  in the entire laminating direction Y and the entire second direction X 2 . This allows the fiber construct  11  to be bent at the part corresponding to the bent portion  18 . Thus, a crank-shaped fiber construct  11  can be manufactured easily. 
     Second Embodiment 
     A fiber construct and a fiber-reinforced composite material according to a second embodiment of the present disclosure will now be described with reference to  FIGS. 4 and 5 . In the description of the second embodiment, the portions similar to those of the first embodiment will not be described in detail. 
     As shown in  FIGS. 4 and 5 , in the first flat portion  16 , the first to fourth weft yarn layers  21  to  24  and the first to eighth warp yarn layers  31  to  38  are all bound by the binding threads  15  in the laminating direction Y. This restricts the weft yarns  13  from moving in the laminating direction Y and the second direction X 2 . The weft yams  13  of the first to fourth weft yam layers  21  to  24  extend straight in the first direction X 1 , and the warp yarns  14  of the first to fourth warp yarn layers  31  to  34  extend straight in the second direction X 2 . Further, all the weft yarns  13  are not engaged with the warp yarns  14  through folding of the weft yarns  13 . 
     In the first flat portion  16 , the first warp yarn layer  31  and the second warp yam layer  32  are arranged between the first weft yarn layer  21  and the second weft yarn layer  22  adjacent to each other in the laminating direction Y. In the second embodiment, the first weft yam layer  21  and the second weft yarn layer  22 , the first warp yam layer  31 , and the second warp yarn layer  32  form a first laminate S 1 . 
     In the first flat portion  16 , the third warp yam layer  33  and the fourth warp yam layer  34  are arranged between the third weft yam layer  23  and the fourth weft yarn layer  24  adjacent to each other in the laminating direction Y. In the second embodiment, the third weft yam layer  23 , the fourth weft yarn layer  24 , the third warp yam layer  33 , and the fourth warp yarn layer  34  form a second laminate S 2 . 
     In the first flat portion  16 , the binding by the binding threads  15  is performed in the same manner as the first embodiment and thus will not be described in detail. 
     The second flat portion  17  and the bent portion  18  include the first to fourth weft yam layers  21  to  24  and the first to fourth warp yam layers  31  to  34 . 
     In the second flat portion  17  and the bent portion  18 , in the warp yarns  14  of the first warp yam layer  31 , the weft yams  13  engaged with the warp yarns  14  through folding of the warp yarns  14  differ between the warp yarns  14  adjacent to the first direction X 1 . That is, in the warp yarns  14  adjacent to each other in the direction perpendicular to the planes of  FIGS. 4 and 5 , the weft yams  13  engaged with the front warp yams  14  through folding of the front warp yarns  14  are different from the weft yarns  13  engaged with the rear warp yarns  14  through folding of the rear warp yarns  14 . The warp yarns  14  that correspond to the first warp yarn layer  31  in the first flat portion  16  are classified into a first group and a second group. The first group includes a warp yarn  14   a   1 . In the second flat portion  17  and the bent portion  18 , the warp yarn  14   a   1  extends along the weft yarns  13  laid out in the second direction X 2  in the first weft yarn layer  21 . The warp yarn  14   a   1  of the first group is in a mode of being engaged with the weft yarns  13  on the opposite sides in the second direction X 2  in the multiple weft yarns  13  by being folded along the surroundings of the cross-sections of these weft yarns  13  and in a mode of being engaged with a single weft yarns  13  adjacent to the opposite weft yarns  13  by being folded along the surroundings of the cross-section of the single weft yarn  13 . These modes are alternately repeated in the second direction X 2 . To facilitate understanding, in  FIGS. 4 and 5 , the warp yarn  14   a   1  of the first group of the first warp yarn layer  31  is folded so as to wave in multiple units. A single unit of the multiples units includes the three weft yarns  13  laid out in the second direction X 2  of the first weft yarn layer  21  and includes the single weft yarn  13  adjacent to the three weft yarns  13 . The number of the weft yarns is not necessarily limited to, for example, three or one. 
     In the two groups of the warp yarns  14  of the first warp yarn layer  31 , the second group includes a warp yarn  14   b   1 . The warp yarn  14   b   1  is in a mode of being engaged by being folded along the surroundings of the cross-section of a single weft yarn  13  of the second weft yarn layer  22  and in a mode of being engaged by being folded along the surroundings of the cross-section of the weft yarn  13  with which the warp yarn  14   a   1  of the first group is engaged in the weft yarns  13  of the first weft yarn layer  21 . These modes are alternately repeated in the second direction X 2 . To facilitate understanding, in  FIGS. 4 and 5 , the warp yarn  14   b   1  of the second group of the first warp yarn layer  31  is in a mode of being folded so as to entangle, from the inner side of the fiber construct  11 , the surroundings of the cross-section of the weft yarn  13  of the second weft yarn layer  22  corresponding to the middle weft yarn  13  of the three weft yarns  13  in the above-described single unit of the first weft yarn layer  21  in the laminating direction Y and engaged with the weft yarn  13  of the second weft yarn layer  22 , and the warp yarn  14   b   1  of the second group of the first warp yarn layer  31  is in a mode of being folded so as to entangle, from the outer side of the fiber construct  11 , the surroundings of the cross-section of the single weft yarn  13  of the single unit and engaged with the weft yarn  13  of the first weft yarn layer  21 . These modes are repeated in the second direction X 2 . The warp yarn  14   b   1  of the second group of the first warp yarn layer  31  extends diagonally with respect to the laminating direction Y to engage with the weft yarn  13  through the folding. Thus, in the first laminate S 1 , the first weft yarn layer  21  and the second weft yarn layer  22  are bonded to each other in the laminating direction Y in a mode in which the warp yarn  14   b   1  of the second group of the first warp yarn layer  31 , which is arranged between the first weft yarn layer  21  and the second weft yarn layer  22 , is engaged by being folded along the surroundings of the cross-sections of the weft yarns  13  of the first weft yarn layer  21  and the second weft yarn layer  22 . 
     In the warp yarns  14  of the second warp yarn layer  32 , the weft yarns  13  engaged with the warp yarns  14  through folding of the warp yarns  14  differ between the warp yarns  14  adjacent to each other in the first direction X 1  (direction perpendicular to the planes of  FIGS. 4 and 5 ). The first group of the warp yarns  14  of the second warp yarn layer  32  includes a warp yarn  14   a   2 . The warp yarn  14   a   2  is in a mode of being engaged by being folded along the surroundings of the cross-section of a single weft yarn  13  of the first weft yarn layer  21  and in a mode of being engaged by being folded along the surroundings of the cross-section of a single weft yarn  13  of the second weft yarn layer  22 . These modes are repeated in the second direction X 2 . To facilitate understanding, in  FIGS. 4 and 5 , the warp yarn  14   a   2  of the first group of the second warp yarn layer  32  is in a mode of being folded so as to entangle, from the outer side of the fiber construct  11 , the surroundings of the cross-section of the middle weft yarn  13  of the three weft yarns  13  of the single unit of the first weft yarn layer  21  and engaged with the weft yarn  13  of the first weft yarn layer  21 , and the warp yarn  14   a   2  of the first group of the second warp yarn layer  32  is in a mode of being folded so as to entangle, from the inner side of the fiber construct  11 , the surroundings of the cross-section of the single weft yarn  13  of the second weft yarn layer  22  corresponding to a single weft yarn  13  of the single unit of the first weft yarn layer  21  in the laminating direction Y. These modes are repeated in the second direction X 2 . The warp yarn  14   a   2  of the first group of the second warp yarn layer  32  extends diagonally with respect to the laminating direction Y to engage with the weft yarn  13  through the folding. Thus, in the first laminate S 1 , the first weft yarn layer  21  and the second weft yarn layer  22  are bonded to each other in the laminating direction Y in a mode in which the warp yarn  14   a   2  of the first group of the second warp yarn layer  32 , which is arranged between the first weft yarn layer  21  and the second weft yarn layer  22 , is engaged by being folded along the cross-sections of the weft yarns  13  of the first weft yarn layer  21  and the second weft yarn layer  22 . 
     Thus, in the second flat portion  17  and the bent portion  18  of the first laminate S 1 , the first laminate S 1  is bound in the laminating direction Y partially through the engagement of the warp yarn  14   b   1  of the second group of the first warp yarn layer  31  and the warp yarn  14   a   2  of the first group of the second warp yarn layer  32 , which are arranged between the first weft yarn layer  21  and the second weft yarn layer  22  adjacent to each other in the laminating direction Y, with the weft yarns  13  of the first weft yarn layer  21  and the second weft yarn layer  22  through folding. 
     The second group of the warp yarns  14  of the second warp yarn layer  32  includes a warp yarn  14   b   2 . The warp yarn  14   b   2  is in a mode of being engaged with a single weft yarn  13  of the third weft yarn layer  23  by being folded along the surroundings of the cross-section of the weft yarn  13  and in a mode of being engaged with a weft yarn  13  with which the warp yarn  14   a   2  of the first group of the second warp yarn layer  32  engages by being folded along the surroundings of the cross-section of the weft yarn  13 . These modes are repeated in the second direction X 2 . The engagements with the weft yarn  13  through the folding causes the warp yarn  14   b   2  of the second group of the second warp yarn layer  32  to extend diagonally with respect to the laminating direction Y. Thus, the warp yarn  14   b   2  of the second group of the second warp yarn layer  32  bonds the second weft yarn layer  22  and the third weft yarn layer  23  to each other in the laminating direction Y. Accordingly, the first laminate S 1  and the second laminate S 2  are bonded to each other in the laminating direction Y. In the present embodiment, the warp yarn  14   b   2  of the second group of the second warp yarn layer  32  functions as a second yarn for one of the laminates of the first laminate S 1  and the second laminate S 2  to bond the first laminate S 1  and the second laminate S 2  to each other in the laminating direction Y. That is, the first laminate S 1  and the second laminate S 2  are bonded to each other in the laminating direction Y in a mode in which the warp yarn  14   b   2  of the second group of the second warp yarn layer  32 , which is a part of the warp yarns  14  of the first laminate S 1  serving as one of the laminates of the first laminate S 1  and the second laminate S 2 , engages with the weft yarns  13  of the second laminate S 2  serving as the other one of the laminates. Thus, in the second flat portion  17  and the bent portion  18  of the first laminate S 1 , the warp yarns  14  are in a mode of binding the first weft yarn layer  21  and the second weft yarn layer  22  partially in the laminating direction. 
     In the warp yarns  14  of the third warp yarn layer  33 , the weft yarns  13  that are engaged with the warp yarns  14  through folding of the warp yarns  14  differ between the warp yarns  14  adjacent to each other in the first direction X 1  (direction perpendicular to the planes of  FIGS. 4 and 5 ). The first group of the warp yarns  14  of the third warp yarn layer  33  includes a warp yarn  14   a   3 . The warp yarn  14   a   3  is in a mode of being engaged with a single weft yarn  13  with which the warp yarn  14   b   1  of the second group of the first warp yarn layer  31  engages by being folded along the surroundings of the cross-section of the weft yarn  13  and in a mode of being engaged by being folded along the surroundings of the cross-section of a single weft yarn  13  of the third weft yarn layer  23 . These modes are repeated in the second direction X 2 . The engagements with the weft yarn  13  through the folding causes the warp yarn  14   a   3  of the first group of the third warp yarn layer  33  to extend diagonally with respect to the laminating direction Y. Thus, the warp yarn  14   a   3  of the first group of the third warp yarn layer  33  bonds the second weft yarn layer  22  and the third weft yarn layer  23  to each other in the laminating direction Y. Accordingly, the first laminate S 1  and the second laminate S 2  are bonded to each other in the laminating direction Y. In the present embodiment, the warp yarn  14   a   3  of the first group of the third warp yarn layer  33  functions as the second yarn for one of the laminates of the first laminate S 1  and the second laminate S 2  to bond the first laminate S 1  and the second laminate S 2  to each other in the laminating direction Y. In other words, the first laminate S 1  and the second laminate S 2  are bonded to each other in the laminating direction Y in a mode in which the warp yarn  14   a   3  of the first group of the third warp yarn layer  33 , which is a part of the warp yarns  14  of the second laminate S 2  serving as one of the laminates of the first laminate S 1  and the second laminate S 2 , engages with the weft yarns  13  of the first laminate S 1  serving as the other one of the laminates. 
     The second group of the third warp yarn layer  33  includes a warp yarn  14   b   3 . The warp yarn  14   b   3  is in a mode of being engaged with a single weft yarn  13  of the fourth weft yarn layer  24  by being folded along the surroundings of the cross-section of the weft yarn  13  and in a mode of being engaged with a weft yarn  13  with which the warp yarn  14   a   3  of the first group of the third warp yarn layer  33  engages by being folded along the surroundings of the cross-section of the weft yarn  13 . These modes are repeated in the second direction X 2 . The engagements with the weft yarn  13  through the folding causes the warp yarn  14   b   3  of the second group of the third warp yarn layer  33  to extend diagonally with respect to the laminating direction Y. Thus, the warp yarn  14   b   3  of the second group of the third warp yarn layer  33  bonds the third weft yarn layer  23  and the fourth weft yarn layer  24  to each other in the laminating direction Y. Accordingly, in the second laminate S 2 , the third weft yarn layer  23  and the fourth weft yarn layer  24  are bonded to each other in the laminating direction Y through the engagement of the warp yarn  14   b   3  of the second group of the third warp yarn layer  33 , which is arranged between the third weft yarn layer  23  and the fourth weft yarn layer  24 , with the weft yarns  13  of the third weft yarn layer  23  and the fourth weft yarn layer  24  by being folded along the surroundings of the cross-sections of these weft yarns  13 . 
     In the warp yarns  14  of the fourth warp yarn layer  34 , the weft yarns  13  engaged with the warp yarns  14  through folding of the warp yarns  14  differ between the warp yarns  14  adjacent to the first direction X 1 . The first group of the warp yarns  14  of the fourth warp yarn layer  34  includes a warp yarn  14   a   4 . The warp yarn  14   a   4  is in a mode of being engaged with a single weft yarn  13  with which the warp yarn  14   b   2  of the second group of the second warp yarn layer  32  engages by being folded along the surroundings of the cross-section of the weft yarn  13  and in a mode of being engaged with a single weft yarn  13  of the fourth weft yarn layer  24  by being folded along the surroundings of the cross-section of the weft yarn  13 . These modes are repeated in the second direction X 2 . The engagements with the weft yarn  13  through the folding causes the warp yarn  14   a   4  of the first group of the fourth warp yarn layer  34  to extend diagonally with respect to the laminating direction Y. Thus, the warp yarn  14   a   4  of the first group of the fourth warp yarn layer  34  bonds the third weft yarn layer  23  and the fourth weft yam layer  24  to each other in the laminating direction Y. 
     Thus, in the second flat portion  17  and the bent portion  18  of the second laminate S 2 , the second laminate S 2  is bound partially in the laminating direction Y through the engagement of the warp yam  14   b   3  of the second group of the third warp yarn layer  33  and the warp yarn  14   a   4  of the first group of the fourth warp yam layer  34 , which are arranged between the third weft yarn layer  23  and the fourth weft yam layer  24  adjacent to each other in the laminating direction Y, with the weft yarns  13  of the weft yam layers  23  and  24 . 
     The second group of the fourth warp yam layer  34  includes a warp yarn  14   b   4  extending along the multiple weft yams  13  of the fourth weft yam layer  24 , which are laid out in the second direction X 2 . The warp yam  14   b   4  of the second group of the fourth warp yam layer  34  is in a mode of being engaged with the weft yams  13  on the opposite ends of these multiple warp yams  13  by being folded along the surroundings of the cross-sections of the opposite weft yams  13  and in a mode of being engaged with a single weft yam  13  with which the warp yarn  14   a   4  of the first group of the fourth warp yarn layer  34  engages by being folded along the surroundings of the cross-section of the weft yam  13 . These modes are repeated in the second direction X 2 . Thus, in the second flat portion  17  and the bent portion  18  of the second laminate S 2 , the warp yarns  14  are in a mode of binding the third weft yarn layer  23  and the fourth weft yarn layer  24  partially in the laminating direction. 
     The warp yarns  14  bind the first laminate S 1  in the laminating direction Y, bind the second laminate S 2  in the laminating direction Y, and bond the first laminate S 1  and the second laminate S 2  to each other in the laminating direction Y. This prevents the bent portion  18  and the second flat portion  17  from being scattered in the laminating direction Y. 
     The binding threads  15  restrict the weft yams  13  from moving in the laminating direction Y and the second direction X 2  in the first flat portion  16 . Further, in the second flat portion  17  and the bent portion  18 , the binding thread  15   a  of the first group in the binding threads  15  is in a mode of being arranged between the first weft yarn layer  21  and the second weft yarn layer  22  to extend straight in the second direction X 2  and is thus not engaged with any weft yarns  13 . Further, in the second flat portion  17  and the bent portion  18 , the binding thread  15   b  of the second group in the binding threads  15  is in a mode of being arranged between the third weft yarn layer  23  and the fourth weft yarn layer  24  to extend straight in the second direction X 2  and is thus not engaged with any weft yarns  13 . 
     Therefore, the second embodiment has the following advantages in addition to the same advantages as (1-1) to (1-4) of the first embodiment. 
     (2-1) In the bent portion  18  and the second flat portion  17 , the first laminate S 1  and the second laminate S 2  are bound partially in the laminating direction Y by the warp yarns  14 , and the first laminate S 1  and the second laminate S 2  are bonded to each other by the warp yarns  14  in the laminating direction Y. This prevents the weft yarns  13  and the warp yarns  14  of the bent portion  18  and the second flat portion  17  from being scattered in the laminating direction Y. 
     (2-2) The warp yarns  14  that bind the laminates S 1  and S 2  extend diagonally with respect to the laminating direction Y. Thus, since the warp yarns  14  bind the laminates S 1  and S 2  extend diagonally with respect to the laminating direction Y, the warp yarns  14  never extend straight in the laminating direction Y. Accordingly, since the warp yarns  14  engaged with the weft yarns  13  never bind the bent portion  18  and the second flat portion  17  in the second direction X 2 , the weft yarn  13  and the warp yarn  14  are allowed to move. 
     Each of the above-illustrated embodiments may be modified as follows. The above-described embodiments and the following modifications may be combined as long as they do not conflict with each other. 
       FIG. 6  shows a fiber construct  11  according to a modification. The fiber construct  11  includes, in the second direction X 2 , the first flat portion  16 , a first bent portion  18   a  with a first end continuous with the first flat portion  16 , and the second flat portion  17  continuous with a second end of the first bent portion  18   a . Further, the fiber construct  11  may include a second bent portion  18   b  with a first end continuous with the second flat portion  17  and a third flat portion  19  continuous with a second end of the second bent portion  18   b . In this case, the first bent portion  18   a , the second flat portion  17 , and the second bent portion  18   b  have the same structure as one of the first and second embodiments. That is, the first bent portion  18   a  and the second bent portion  18   b  in  FIG. 6  are structured in the same manner as the bent portion  18  in the first and second embodiments, and the second flat portion  17  in  FIG. 6  is structured in the same manner as the first flat portion  16  in the first and second embodiments. This structure prevents the binding threads  15  from binding in the entire laminating direction Y. The third flat portion  19  is bound by the binding threads  15  in the entire laminating direction Y. For example, the third flat portion  19  in  FIG. 6  is structured in the same manner as the first flat portion  16  of the first and second embodiments. 
     As shown in  FIG. 7 , the binding threads  15  in the first embodiment may be changed to be in a mode of being absent in the second flat portion  17  and the bent portion  18 , and the binding threads  15  may be arranged only in the first flat portion  16 . Alternatively, as shown in  FIG. 8 , the binding threads  15  in the second embodiment may be changed to be in a mode of being absent in the second flat portion  17  and the bent portion  18 , and the binding threads  15  may be arranged only in the first flat portion  16 . In these cases, in the second flat portion  17  and the bent portion  18 , the weft yarns  13  and the warp yarns  14  can be easily moved through bending as compared with, for example, when the binding threads  15  bind all the fiber layers or when the binding threads  15  perform partial binding in the laminating direction Y and the first direction X 1 . 
     In the first embodiment and the second embodiment, the second flat portion  17  and the bent portion  18  are shaped to be bent in the second direction X 2 , in which the yarn main axis of the warp yams  14  extend. Instead, parts of the second flat portion  17  and the bent portion  18  may be shaped to be bent in the first direction X 1  in addition to the second direction X 2 . That is, the second flat portion  17  and the bent portion  18  may not only be bent around the axis extending in the first direction X 1  but also be bent along around another axis extending in the second direction X 2 . In this case, the weft yarns  13  configuring the parts bent in the first direction X 1  and the second direction X 2  are not arranged in parallel to one another, and the warp yams  14  are also not arranged in parallel to one another. 
     In the first embodiment and the second embodiment, in the second flat portion  17  and the bent portion  18 , as long as the weft yarns  13  and the warp yams  14  are allowed to move in the second direction X 2 , the weft yams  13  may be in a mode of being engaged with the warp yarns  14  by being folded along the surroundings of the cross-sections of the warp yams  14  partially in the laminating directions of the second flat portion  17  and the bent portion  18 . 
     In the second embodiment, in the bent portion  18  and the second flat portion  17 , the positions of the weft yams  13  with which the warp yarns  14  are engaged may be changed to the second direction X 2 . 
     In the second embodiment of  FIGS. 4 and 5 , the laminates Si and S 2  are bound partially in the laminating direction Y by the warp yarns  14  other than the warp yam  14   a   1  of the first group of the first warp yam layer  31  and the warp yam  14   b   4  of the second group of the fourth warp yarn layer  34 . Thus, the warp yams  14  are in a mode of being engaged with the weft yarns  13  of the weft yam layers adjacent to each other in the laminating direction Y. However, the warp yams  14  do not have to be engaged with the weft yams  13  in this manner. The warp yarns  14  binding the laminates  51  and S 2  partially in the laminating direction Y may be in a mode of extending across three-layer weft yam layers to engage with the weft yarns  13  of the weft yarn layers of the opposite ends of the three-layer weft yam layers in the laminating direction Y. For example, the warp yarn  14   b   1  of the second group of the first warp yarn layer  31  may in a mode of extending across the first weft yam layer  21 , the second weft yarn layer  22 , and the third weft yarn layer  23  to engage with the weft yam  13  of the first weft yam layer  21  and the weft yam  13  of the third weft yarn layer  23 . 
     In a structure in which the weft yarns  13  and the warp yams  14  are allowed to move in the laminating direction Y and the second direction X 2 , the shape of the fiber construct  11  does not have to be L-shaped and may be changed. 
     In the first flat portion  16 , each binding thread  15  is folded for the corresponding weft yam  13 . However, the position where the binding thread  15  is folded may be changed in correspondence with, for example, a desired strength of the first flat portion  16 . 
     The first yams may be the warp yams  14 , and the second yams may be the weft yams  13 . 
     In the first embodiment and the second embodiment, in the second flat portion  17  and the bent portion  18 , the binding threads  15  may be in a mode of binding the first fiber layers and the second fiber layers partially in the laminating direction Y. In this case, the binding threads  15  simply need to be configured such that the binding threads  15  do not bind all the first fiber layers and the second fiber layers. Even in such a structure, in the second flat portion  17  and the bent portion  18 , as compared with when the binding threads  15  bind all the fiber layers, the weft yams  13  and the warp yams  14  easily move through bending. 
     The technical ideas obtainable from the above embodiments and the modifications are described below. 
     The above-described fiber construct, wherein a dimension of the fiber construct extending through an inner side of the bent portion in the second direction slightly deviates from a dimension of the fiber construct extending through an outer side of the bent portion in the second direction. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
     S 1 ) First Laminate S 2 ) Second Laminate; X 1 ) First direction; X 2 ) Second Direction;  10 ) Fiber-Reinforced Composite Material;  11 ) Fiber Construct;  12 ) Matrix Resin;  13 ) Weft as First Yarn;  14 ) Warp as Second Yarn;  15 ) Binding Thread;  16 ) First Flat Portion;  17 ) Second Flat Portion;  18 ) Bent Portion;  21 - 24 ) First to Fourth Weft Yarn Layers as First Fiber Layers;  31 - 38 ) First to Eighth Warp Yam Layers as Second Fiber Layers