Fiber structures for fiber-reinforced composites

Abstract

To provide a fiber structure for a fiber-reinforced composite material, which can suppress the deviation of selvage yarns.SOLUTION: In a fiber structure for a fiber-reinforced composite material, a laminate 20 is formed in such a manner that a warp layer 21 in which a plurality of warp yarns 23 extending in a first direction X are arranged in a second direction Y and at least two weft layers 22 in which a plurality of weft yarns 24 which are reinforcing fiber yarns extending in the second direction Y are arranged in the first direction X, are laminated in a lamination direction Z. The laminate 20 has end portions 20a located at both ends in the second direction Y and formed by the plurality of weft layers 22 arranged in the lamination direction Z, and general portions 20b located between the end portions 20a in the second direction Y. In the end portion 20a, a selvage yarn 40 is engaged with the weft yarns 24 of the weft layers 22 located at both ends in the lamination direction Z. Some of the warp yarns 23 are binding yarns which bind the warp layer 21 and the weft layer 22 together by being engaged with the weft yarns 24. The selvage yarn 40 is a continuous yarn. In the end portion 20a, the weft yarns 24 of the weft layers 22 located at both ends in the lamination direction Z are spun yarns.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fiber structure for a fiber-reinforced composite material. [Background technology]

[0002] Patent Document 1 discloses a fiber structure used in a fiber-reinforced composite material. The fiber structure has a warp layer and a weft layer. The warp layer is formed by arranging a plurality of warp threads extending in a first direction in a second direction that is perpendicular to the first direction. The weft layer is formed by arranging a plurality of weft threads, which are reinforcing fiber threads extending in the second direction, in the first direction.

[0003] The fiber structure of Patent Document 1 has a laminate in which warp layers and weft layers are stacked in a stacking direction that is perpendicular to both the first direction and the second direction. The laminate has end portions and a general portion. The end portions are located at both ends of the laminate in the second direction. The end portions are composed of multiple weft layers arranged in the stacking direction. The general portion is located between the end portions in the second direction. The general portion is provided with a connecting thread that connects the warp layer and the weft layer by engaging with the weft thread.

[0004] In a fiber structure such as that disclosed in Patent Document 1, it is known to provide selvage yarns that engage with the weft yarns at the ends in the second direction in order to prevent fraying of the weft yarns at the ends in the second direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-178299 Summary of the Invention [Problem to be solved by the invention]

[0006] When the weft yarn is a continuous yarn, the surface of the weft yarn is smooth. Therefore, the selvage yarns easily slide against the weft yarn. If the selvage yarns shift so that they spread outward in the second direction, fraying occurs at both ends of the fiber structure in the second direction. [Means for solving the problem]

[0007] A fiber structure for fiber-reinforced composites that solves the above-mentioned problems is summarized as follows: a warp layer in which warp yarns extending in a first direction are arranged in a second direction that is perpendicular to the first direction; and at least two weft layers in which weft yarns, which are reinforcing fiber yarns extending in the second direction, are arranged in the first direction, stacked in a stacking direction that is perpendicular to both the first and second directions; the fiber structure having end portions located at both ends in the second direction and constituted by the plurality of weft layers arranged in the stacking direction; and a general portion located between the end portions in the second direction; and selvage yarns that engage with the weft yarns of the weft layer located at at least one end in the stacking direction at the end portions, wherein at least some of the warp yarns are connecting yarns that connect the warp layer and the weft layer by engaging with the weft yarns in the general portion, and the selvage yarns are continuous yarns, and the wefts of the weft layers located at both ends in the stacking direction at the end portions are spun yarns.

[0008] The selvage yarn is engaged with the weft yarn of the weft layer located at at least one end in the stacking direction at the end of the laminate. The selvage yarn is a continuous yarn. The weft yarns of the weft layers located at both ends in the stacking direction at the end are spun yarns. The coefficient of friction of the surface of the spun yarn is greater than the coefficient of friction of the surface of the continuous yarn. Therefore, the selvage yarn is less likely to slip against the weft yarn of the weft layer located at at least one end in the stacking direction at the end. This can suppress slippage of the selvage yarn in the second direction. As a result, fraying is less likely to occur at both ends of the fiber structure in the second direction.

[0009] In the fiber structure for a fiber-reinforced composite material, the binding yarn that engages with the weft yarn that is the spun yarn may be a continuous yarn. In the above configuration, the strength of the fiber reinforced composite material is improved compared to when the binding yarn that engages with the weft yarn, which is a spun yarn, is a spun yarn.

[0010] For example, if the selvage yarns are spun yarns and the weft yarns in the weft layers located at both ends of the end in the stacking direction are continuous yarns, the selvage yarns are less likely to slip relative to the weft yarns, but the binding yarns are more likely to slip relative to the weft yarns. In contrast, in this embodiment, the selvage yarns are continuous yarns, and the weft yarns in the weft layers located at both ends of the end in the stacking direction are spun yarns. Therefore, not only the selvage yarns but also the binding yarns are less likely to slip relative to the weft yarns. Therefore, the misalignment of the binding yarns in the second direction can also be suppressed.

[0011] In the fiber structure for a fiber-reinforced composite material, the wefts of the weft layers other than the weft layers located at both ends in the stacking direction at the end portion may be continuous yarns. In the above configuration, the strength of the fiber reinforced composite material is improved compared to when the weft yarns of the weft layers other than the weft layers located at both ends in the stacking direction at the end of the laminate are also spun yarns.

[0012] In the above-mentioned fiber structure for fiber-reinforced composites, the selvage yarns may be alternately engaged one by one with the weft yarn of the weft layer located at one end of the stacking direction and the weft yarn of the weft layer located at the other end of the stacking direction.

[0013] In the above configuration, the selvage yarns are less likely to slip out of place compared to when multiple yarns are alternately engaged with the weft yarn of the weft layer located at one end of the stacking direction and the weft yarn of the weft layer located at the other end of the stacking direction. [Effects of the Invention]

[0014] According to the present invention, slippage of selvage yarns can be suppressed. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view schematically showing a fiber structure according to a first embodiment. [Figure 2]FIG. 1 is a plan view schematically showing a fiber structure according to a first embodiment. [Figure 3] FIG. 10 is a perspective view schematically showing a fiber structure according to a second embodiment. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a fiber structure according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] [First embodiment] A first embodiment of a fiber structure for fiber-reinforced composites will be described below with reference to Figs. 1 and 2. The fiber structure for fiber-reinforced composites is a fiber structure used in fiber-reinforced composites. Fiber-reinforced composites are formed by compounding a fiber structure in a matrix (not shown). The fiber structure is a reinforcing substrate for the fiber-reinforced composites. The matrix is, for example, an epoxy resin, a thermosetting resin. Hereinafter, the "fiber structure for fiber-reinforced composites" will be simply referred to as the "fiber structure."

[0017] As shown in FIG. 1, the fiber structure 10 includes a laminate 20 and selvedge yarns 40. <Laminate> The laminate 20 has a warp layer 21 and a weft layer 22. The fiber structure 10 of the present embodiment has three warp layers 21 and three weft layers 22. The laminate 20 is formed by laminating the warp layers 21 and the weft layers 22. The direction in which the warp layers 21 and the weft layers 22 are laminated is defined as a lamination direction Z. The lamination direction Z is a direction perpendicular to both a first direction X and a second direction Y described below.

[0018] The warp layer 21 has a plurality of warp threads 23. The warp threads 23 extend in a first direction X. The plurality of warp threads 23 are arranged in a second direction Y, which is a direction perpendicular to the first direction X. In other words, the warp layer 21 is formed by arranging a plurality of warp threads 23 extending in the first direction X in the second direction Y.

[0019] In this embodiment, of the three warp layers 21, two warp layers 21 are first warp layers 21a and one warp layer 21 is second warp layer 21b. The first warp layer 21a is formed by arranging a plurality of first warp threads 23a as warp threads 23 extending in the first direction X in the second direction Y. The second warp layer 21b is formed by arranging a plurality of second warp threads 23b as warp threads 23 extending in the first direction X in the second direction Y. The first warp threads 23a and the second warp threads 23b are arranged alternately in the second direction Y. The warp threads 23 located at both ends in the second direction Y are first warp threads 23a.

[0020] The first warp threads 23a are reinforcing fiber threads. The reinforcing fiber in this embodiment is carbon fiber. The second warp threads 23b are threads made of phenoxy resin. The first warp threads 23a and the second warp threads 23b are each continuous threads formed by bundling continuous fibers. The second warp threads 23b are thinner threads than the first warp threads 23a. The first warp threads 23a extend linearly along the first direction X. The second warp threads 23b extend in the first direction X while meandering in the stacking direction Z. A detailed configuration of the second warp threads 23b will be described later.

[0021] The weft layer 22 has a plurality of weft threads 24. The weft threads 24 extend linearly along the second direction Y. The plurality of weft threads 24 are arranged in the first direction X. In other words, the weft layer 22 is formed by arranging a plurality of weft threads 24 extending in the second direction Y in the first direction X. Both ends of the weft layer 22 in the second direction Y protrude outward beyond the warp threads 23 located at both ends in the second direction Y. The weft threads 24 are reinforcing fiber threads. The reinforcing fiber in this embodiment is carbon fiber.

[0022] The laminate 20 has a pair of end portions 20a and a general portion 20b. The end portions 20a are located at both ends of the laminate 20 in the second direction Y. Specifically, the pair of end portions 20a are located outside the warp yarns 23 located at both ends in the second direction Y. The end portions 20a are formed by a plurality of weft yarn layers 22 arranged in the stacking direction Z. Specifically, the pair of end portions 20a are formed by stacking both ends of the weft yarn layers 22 in the second direction Y in the stacking direction Z.

[0023] At the end 20a, the wefts 24 of the weft layers 22 located at both ends in the stacking direction Z are spun yarns formed by bundling discontinuous fibers. On the other hand, at the end 20a, the wefts 24 of the weft layers 22 other than the weft layers 22 located at both ends in the stacking direction Z are continuous yarns. In this embodiment, the weft layers 22 other than the weft layers 22 located at both ends in the stacking direction Z refer to one weft layer 22 located between the weft layers 22 located at both ends in the stacking direction Z.

[0024] The general portion 20b is located between the pair of end portions 20a in the second direction Y. The general portion 20b is composed of a plurality of warp layers 21 and a plurality of weft layers 22 arranged in the stacking direction Z. In the general portion 20b, the first warp layers 21a and the weft layers 22 are alternately stacked in the stacking direction Z. The first warp layers 21a are located between the weft layers 22 in the stacking direction Z. In the general portion 20b, the second warp layers 21b are stacked with the weft layers 22 at both ends in the stacking direction Z.

[0025] As shown in FIG. 2, the second warp threads 23b have a plurality of first warp thread engaging portions 31, a plurality of second warp thread engaging portions 32, and a plurality of warp thread connecting portions 33. The first warp engagement portion 31 is a portion engaged with the weft 24 of the weft layer 22 located at the first end in the stacking direction Z. The first warp engagement portion 31 is formed by folding back the second warp 23b so that it passes outside the weft 24 of the weft layer 22 located at the first end in the stacking direction Z. The first warp engagement portion 31 is stacked on the weft 24 of the weft layer 22 located at the first end in the stacking direction Z. In this embodiment, the first warp engagement portion 31 is engaged with two wefts 24 of the weft layer 22 located at the first end in the stacking direction Z.

[0026] The second warp engagement portion 32 is a portion of the weft 24 of the weft layer 22 located at a second end opposite the first end in the stacking direction Z, which is engaged with the weft 24 adjacent in the first direction X to the weft 24 engaged by the first warp engagement portion 31. The second warp engagement portion 32 is formed by folding back the second warp 23b so that it passes outside the weft 24 of the weft layer 22 located at the second end in the stacking direction Z. The second warp engagement portion 32 is stacked with respect to the weft 24 of the weft layer 22 located at the second end in the stacking direction Z. In this embodiment, the second warp engagement portion 32 is engaged with two wefts 24 of the weft layer 22 located at the second end in the stacking direction Z.

[0027] The warp thread connection portion 33 is a portion that connects the first warp thread engagement portion 31 and the second warp thread engagement portion 32. The warp thread connection portion 33 extends along the lamination direction Z between the weft thread 24 with which the first warp thread engagement portion 31 is engaged in the first direction X and the weft thread 24 with which the second warp thread engagement portion 32 is engaged.

[0028] In the second warp thread 23b, the first warp thread engaging portion 31 and the second warp thread engaging portion 32 are alternately and repeatedly arranged via the warp thread connecting portion 33. The second warp thread 23b is alternately engaged with the weft thread 24 of the weft thread layer 22 located at the first end in the stacking direction Z and the weft thread 24 of the weft thread layer 22 located at the second end in the stacking direction Z. In this embodiment, the second warp thread 23b is alternately engaged with the weft thread 24 of the weft thread layer 22 located at the first end in the stacking direction Z and the weft thread 24 of the weft thread layer 22 located at the second end in the stacking direction Z, two by two.

[0029] Two second warp threads 23b adjacent to each other in the second direction Y with a first warp thread 23a interposed therebetween are engaged with weft threads 24 of the weft layer 22 located at both ends in the stacking direction Z through different routes. Specifically, the first warp thread engagement portion 31 of one second warp thread 23b and the second warp thread engagement portion 32 of the other second warp thread 23b are aligned in the second direction Y. In addition, the second warp thread engagement portion 32 of one second warp thread 23b and the first warp thread engagement portion 31 of the other second warp thread 23b are aligned in the second direction Y.

[0030] The second warp yarn 23b is a binder yarn that binds the warp layer 21 and the weft layer 22 by engaging with the weft yarn 24 of the weft layer 22 located at both ends in the stacking direction Z. Therefore, in this embodiment, some of the warp yarns 23 are binder yarns that bind the warp layer 21 and the weft layer 22 by engaging with the weft yarn 24 in the general portion 20b. Note that the weft yarn 24 with which the second warp yarn 23b is engaged in the general portion 20b is the weft yarn 24 of the weft layer 22 located at both ends in the stacking direction Z at the end portion 20a. Therefore, the weft yarn 24 with which the second warp yarn 23b is engaged is a spun yarn. Also, as described above, the second warp yarn 23b is a continuous yarn. Therefore, the binder yarn that engages with the weft yarn 24, which is a spun yarn, is a continuous yarn.

[0031] <Selvedge thread> Two selvage yarns 40 are provided for each end 20a of the laminate 20. The selvage yarns 40 are located outward of the general portion 20b in the second direction Y. The selvage yarns 40 extend in the first direction X while meandering in the lamination direction Z. The selvage yarns 40 are threads made of phenoxy resin. The selvage yarns 40 are continuous threads. The selvage yarns 40 are thinner threads than the first warp threads 23a.

[0032] The selvage yarn 40 has a plurality of first selvage yarn engaging portions 41, a plurality of second selvage yarn engaging portions 42, and a plurality of selvage yarn connecting portions 43. The first selvage yarn engaging portion 41 is a portion engaged with the weft yarn 24 of the weft layer 22 located at the first end in the stacking direction Z. The first selvage yarn engaging portion 41 is formed by folding back the selvage yarn 40 so that it passes outside the weft yarn 24 of the weft layer 22 located at the first end in the stacking direction Z. In this embodiment, the first selvage yarn engaging portion 41 is engaged with one weft yarn 24 of the weft layer 22 located at the first end in the stacking direction Z.

[0033] The second selvage yarn engaging portion 42 is a portion of the weft yarn 24 of the weft layer 22 located at the second end in the stacking direction Z that is engaged with a weft yarn 24 adjacent in the first direction X to the weft yarn 24 engaged with the first selvage yarn engaging portion 41. The second selvage yarn engaging portion 42 is formed by folding back the selvage yarn 40 so that it passes outside the weft yarn 24 of the weft layer 22 located at the second end in the stacking direction Z. In this embodiment, the second selvage yarn engaging portion 42 is engaged with one weft yarn 24 of the weft layer 22 located at the second end in the stacking direction Z.

[0034] The selvage yarn connecting portion 43 is a portion that connects the first selvage yarn engaging portion 41 and the second selvage yarn engaging portion 42. The selvage yarn connecting portion 43 extends along the layering direction Z between the weft yarn 24 with which the first selvage yarn engaging portion 41 is engaged in the first direction X and the weft yarn 24 with which the second selvage yarn engaging portion 42 is engaged.

[0035] In the selvage yarn 40, the first selvage yarn engaging portions 41 and the second selvage yarn engaging portions 42 are alternately arranged via selvage yarn connecting portions 43. The selvage yarn 40 is alternately engaged with the weft yarn 24 of the weft layer 22 located at the first end in the stacking direction Z and the weft yarn 24 of the weft layer 22 located at the second end in the stacking direction Z. In this embodiment, the selvage yarn 40 is alternately engaged with the weft yarn 24 of the weft layer 22 located at the first end in the stacking direction Z and the weft yarn 24 of the weft layer 22 located at the second end in the stacking direction Z, one by one.

[0036] The two selvage yarns 40 located at each end 20a travel through different routes and are engaged with weft yarns 24 of the weft layers 22 located at both ends in the stacking direction Z. More specifically, the first selvage yarn engaging portion 41 of one selvage yarn 40 and the second selvage yarn engaging portion 42 of the other selvage yarn 40 are aligned in the second direction Y. Furthermore, the second selvage yarn engaging portion 42 of one selvage yarn 40 and the first selvage yarn engaging portion 41 of the other selvage yarn 40 are aligned in the second direction Y.

[0037] [Actions and Effects of This Embodiment] The operation and effects of this embodiment will be described. (1) At the end 20a of the laminate 20, the selvage yarns 40 are engaged with the weft yarns 24 of the weft layer 22 located at both ends in the stacking direction Z. The selvage yarns 40 are continuous yarns. The weft yarns 24 of the weft layer 22 located at both ends in the stacking direction Z at the end 20a are spun yarns. The coefficient of friction of the surface of a spun yarn is greater than the coefficient of friction of the surface of a continuous yarn. Therefore, the selvage yarns 40 are less likely to slip relative to the weft yarns 24 of the weft layer 22 located at both ends in the stacking direction Z at the end 20a. This prevents the selvage yarns 40 from slipping in the second direction Y. As a result, fraying is less likely to occur at both ends of the fiber structure 10 in the second direction Y.

[0038] (2) The warp yarns 23 as binding yarns that engage with the weft yarns 24, which are spun yarns, are continuous yarns. Therefore, the strength of the reinforced fiber composite material is improved compared to when the warp yarns 23 as binding yarns that engage with the weft yarns 24, which are spun yarns, are spun yarns.

[0039] For example, if the selvage yarns 40 are spun yarns and the weft yarns 24 of the weft layers 22 located at both ends of the end 20a in the stacking direction Z are continuous yarns, the selvage yarns 40 will not slip easily relative to the weft yarns 24, but the warp yarns 23 serving as binding yarns will easily slip relative to the weft yarns 24. In contrast, in this embodiment, the selvage yarns 40 are continuous yarns and the weft yarns 24 of the weft layers 22 located at both ends of the end 20a in the stacking direction Z are spun yarns. Therefore, not only the selvage yarns 40 but also the warp yarns 23 serving as binding yarns will not easily slip relative to the weft yarns 24. Therefore, not only the selvage yarns 40 but also the warp yarns 23 serving as binding yarns can be prevented from slipping in the second direction Y, but also the warp yarns 23 serving as binding yarns can be prevented from slipping in the second direction Y.

[0040] (3) Of the multiple weft layers 22, the weft yarns 24 of the weft layers 22 located at both ends in the stacking direction Z at the end 20a are spun yarns, and the weft yarns 24 of the other weft layers 22 are continuous yarns. That is, of the multiple weft layers 22, the weft yarns 24 of the weft layers 22 other than the weft layers 22 located at both ends in the stacking direction Z at the end 20a are continuous yarns. Therefore, the strength of the fiber-reinforced composite is improved compared to when the weft yarns 24 of the weft layers 22 other than the weft layers 22 located at both ends in the stacking direction Z at the end 20a are also spun yarns.

[0041] (4) The selvage yarns 40 are alternately engaged one by one with the weft yarn 24 of the weft layer 22 located at the first end, which is one end of the stacking direction Z, and the weft yarn 24 of the weft layer 22 located at the second end, which is the other end of the stacking direction Z. This makes the selvage yarns 40 less likely to slip out of place compared to when multiple selvage yarns 40 are alternately engaged with the weft yarn 24 of the weft layer 22 located at the first end of the stacking direction Z and the weft yarn 24 of the weft layer 22 located at the second end of the stacking direction Z.

[0042] [Second embodiment] A second embodiment of a fiber structure for a fiber-reinforced composite material will be described below with reference to Figs. 3 and 4. The second embodiment differs from the first embodiment mainly in the configuration of the warp layer 21. Description of the same configuration as the first embodiment will be omitted.

[0043] As shown in FIGS. 3 and 4, the laminate 20 of this embodiment is formed by laminating four warp layers 21 and six weft layers 22 in the lamination direction Z. The warp layer 21 of this embodiment has first bonding warp threads 23c and second bonding warp threads 23d as warp threads 23. The first bonding warp threads 23c and the second bonding warp threads 23d each extend in the first direction X. The first bonding warp threads 23c and the second bonding warp threads 23d are arranged alternately in the second direction Y. In other words, the warp layer 21 is formed by arranging the first bonding warp threads 23c and the second bonding warp threads 23d, which extend in the first direction X, alternately in the second direction Y. In this embodiment, the warp threads 23 located at both ends in the second direction Y are the first bonding warp threads 23c.

[0044] The first binding warp threads 23c and the second binding warp threads 23d are each a fiber-reinforced yarn. The reinforcing fiber in this embodiment is carbon fiber. The first binding warp threads 23c and the second binding warp threads 23d are each a continuous yarn.

[0045] The first bonding warp thread 23c is engaged with the weft thread 24 of one weft layer 22. More specifically, the first bonding warp thread 23c is engaged with the weft thread 24 by passing alternately on one side and the other side of the weft thread 24 in the stacking direction Z relative to the weft thread 24 arranged in the first direction X as one weft layer 22. The first bonding warp thread 23c is a bonding thread that bonds the warp layer 21 and the weft layer 22 by being engaged with the weft thread 24 in the general portion 20b.

[0046] The second bonding warp thread 23d is engaged with the weft threads 24 of the weft layer 22 located on both sides in the stacking direction Z of the weft layer 22 with which the first bonding warp thread 23c is engaged. More specifically, the second bonding warp thread 23d is engaged with the weft thread 24 by passing alternately between the outside of the weft thread 24 of the weft layer 22 located on one side in the stacking direction Z of the weft layer 22 with which the first bonding warp thread 23c is engaged and the outside of the weft thread 24 of the weft layer 22 located on the other side in the stacking direction Z of the weft layer 22 with which the first bonding warp thread 23c is engaged. The second bonding warp thread 23d is engaged with the weft thread 24 in the general portion 20b, thereby serving as a bonding thread that bonds the warp layer 21 and the weft layer 22. Therefore, in this embodiment, all of the warp threads 23 are bonding threads that bond the warp layer 21 and the weft layer 22.

[0047] In addition, some of the weft yarns 24 that engage with the warp yarns 23 in the general portion 20b are weft yarns 24 of the weft layers 22 located at both ends in the stacking direction Z at the end portion 20a. Therefore, some of the weft yarns 24 that engage with the warp yarns 23 are spun yarns. Also, as described above, the warp yarns 23 are continuous yarns. Therefore, the binding yarns that engage with the weft yarns 24, which are spun yarns, are continuous yarns.

[0048] As described in the first embodiment, the weft layer 22 is formed by arranging a plurality of weft threads 24 extending in the second direction Y in the first direction X. In this embodiment, the number of weft threads 24 in the weft layers 22 located at both ends in the stacking direction Z is less than the number of weft threads 24 in the four weft layers 22 located between the weft layers 22 located at both ends in the stacking direction Z. The weft threads 24 in the weft layers 22 located at both ends in the stacking direction Z are arranged so as to overlap in the stacking direction Z every other weft thread 24 in the first direction X with the weft threads 24 in the weft layers 22 located between the weft layers 22 located at both ends in the stacking direction Z.

[0049] In the second embodiment, the same effects as those (1) to (4) of the first embodiment can be obtained. [Example of change] The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0050] The reinforcing fibers are not limited to carbon fibers, but may be glass fibers, silicon carbide ceramic fibers, aramid fibers, ultra-high molecular weight polyethylene fibers, or the like. In the first embodiment, the number of weft layers 22 is not limited to three. The number of weft layers 22 may be changed as appropriate as long as there are two or more weft layers 22. Furthermore, the number of first warp layers 21a is not limited to two. The number of first warp layers 21a may be changed as appropriate. However, the first warp layers 21a are assumed to be located between the weft layers 22 in the stacking direction Z. Two or more first warp layers 21a may be disposed between the weft layers 22 adjacent to each other in the stacking direction Z.

[0051] In the first embodiment, the first warp threads 23a do not have to be reinforced fiber threads. The first warp threads 23a may be, for example, phenoxy resin threads or nylon threads. Furthermore, the second warp threads 23b do not have to be phenoxy resin threads. The second warp threads 23b may be, for example, nylon threads or reinforced fiber threads. When neither the first warp threads 23a nor the second warp threads 23b are reinforced fiber threads, the fiber structure 10 is a fiber structure for a unidirectional fiber-reinforced composite material that is reinforced only in the second direction Y by the weft threads 24, which are reinforced fibers.

[0052] In the first embodiment, the first warp yarn 23a may be a spun yarn. In the first embodiment, the second warp yarn 23b may be a spun yarn. In the first embodiment, the second warp threads 23b may be alternately engaged with the weft threads 24 of the weft layer 22 located at the first end in the stacking direction Z and the weft threads 24 of the weft layer 22 located at the second end in the stacking direction Z. The second warp threads 23b may be alternately engaged with the weft threads 24 of the weft layer 22 located at the first end in the stacking direction Z and the weft threads 24 of the weft layer 22 located at the second end in the stacking direction Z, three or more of which may be alternately engaged with each other.

[0053] In the first embodiment, two second warp threads 23b may be arranged between adjacent warp threads 23 in the second direction Y. The second warp threads 23b are engaged with the weft threads 24 through different routes. In the second embodiment, the number of weft layers 22 is not limited to six. The number of weft layers 22 may be changed as appropriate as long as there are two or more weft layers 22. Furthermore, the number of warp layers 21 is not limited to four. The number of warp layers 21 may be changed as appropriate as long as the warp layers 21 and the weft layers 22 can be connected by the warp threads 23.

[0054] In the second embodiment, the warp yarns 23 do not have to be reinforcing fiber yarns. The warp yarns 23 may be, for example, yarns made of phenoxy resin or nylon. In this case, the fiber structure 10 is a fiber structure for a unidirectional fiber-reinforced composite material that is reinforced only in the second direction Y by the weft yarns 24, which are reinforcing fiber yarns.

[0055] In the second embodiment, the warp yarns 23 may be spun yarns. In the second embodiment, the warp threads 23 located at both ends in the second direction Y may be second connecting warp threads 23d. Alternatively, the warp threads 23 located at one end in the second direction Y may be first connecting warp threads 23c, and the warp threads 23 located at the other end in the second direction Y may be second connecting warp threads 23d.

[0056] In each embodiment, the weft yarns 24 of the weft layers 22 other than the weft layers 22 located at both ends in the stacking direction Z at the end portion 20a may also be spun yarns. In each embodiment, the selvage yarns 40 do not have to be made of phenoxy yarns. The selvage yarns 40 may be made of nylon yarns or reinforced fiber yarns, for example.

[0057] In each embodiment, the selvage yarn 40 may be engaged only with the weft yarn 24 of the weft layer 22 located at the first end in the stacking direction Z. In this case, the selvage yarn 40 is turned back in the middle of the stacking direction Z, and is therefore not engaged with the weft yarn 24 of the weft layer 22 located at the second end in the stacking direction Z. As another example, the selvage yarn 40 may be engaged only with the weft yarn 24 of the weft layer 22 located at the second end in the stacking direction Z. In this case, the selvage yarn 40 is turned back in the middle of the stacking direction Z, and is therefore not engaged with the weft yarn 24 of the weft layer 22 located at the first end in the stacking direction Z. In other words, it is sufficient that the selvage yarn 40 is engaged with the weft yarn 24 of the weft layer 22 located at at least one end in the stacking direction Z. Note that "at least one end in the stacking direction" means only one end in the stacking direction, only the other end in the stacking direction, or both ends in the stacking direction.

[0058] In each embodiment, the selvage yarns 40 do not have to be alternately engaged with the weft yarn 24 of the weft layer 22 located at the first end in the stacking direction Z and the weft yarn 24 of the weft layer 22 located at the second end in the stacking direction Z. The selvage yarns 40 may be alternately engaged with the weft yarn 24 of the weft layer 22 located at the first end in the stacking direction Z and the weft yarn 24 of the weft layer 22 located at the second end in the stacking direction Z, with multiple weft yarns 40 intertwined.

[0059] The matrix is not limited to epoxy resin. The matrix may be other thermosetting resins such as vinyl ester resin, unsaturated polyester resin, and phenolic resin. The matrix may also be thermoplastic resins such as polyamide, polybutylene terephthalate, polycarbonate, polyethylene, polypropylene, polyimide resin, and ABS resin. [Explanation of symbols]

[0060] 10...fiber structure for fiber-reinforced composite material, 20...laminated body, 20a...end portion, 20b...general portion, 21...warp layer, 22...weft layer, 23...warp thread, 23b...second warp thread as bonding thread, 23c...first bonding warp thread as bonding thread, 23d...second bonding warp thread as bonding thread, 24...weft thread, 40...selvage thread, X...first direction, Y...second direction, Z...stacking direction.

Claims

1. A warp layer in which a plurality of warp yarns extending in a first direction are arranged in a second direction that is a direction perpendicular to the first direction, and at least two weft layers in which a plurality of weft yarns that are reinforcing fiber yarns extending in the second direction are arranged in the first direction are laminated in a lamination direction that is a direction perpendicular to both the first direction and the second direction, a laminate having end portions located at both ends in the second direction and configured by a plurality of the weft layers arranged in the stacking direction, and a general portion located between the end portions in the second direction; a selvedge yarn engaged with the weft yarn of the weft layer located at at least one end in the stacking direction at the end portion; Equipped with A fiber structure for a fiber-reinforced composite material, wherein at least a part of the warp yarns are binding yarns that bind the warp layer and the weft layer by being engaged with the weft yarns in the general portion, The selvedge yarn is a continuous yarn, A fiber structure for a fiber-reinforced composite material, characterized in that the weft yarns of the weft yarn layers located at both ends in the stacking direction at the end portion are spun yarns.

2. 2. The fiber structure for a fiber-reinforced composite material according to claim 1, wherein the binding yarn that engages with the weft yarn that is the spun yarn is a continuous yarn.

3. 3. The fiber structure for a fiber-reinforced composite material according to claim 1, wherein the wefts of the weft layers other than the weft layers located at both ends in the stacking direction at the end portions are continuous wefts.

4. The fiber structure for fiber-reinforced composites according to claim 3, wherein the selvage yarns are alternately engaged one by one with the weft yarn of the weft layer located at one end of the stacking direction and the weft yarn of the weft layer located at the other end of the stacking direction.

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