Fiber structure for fiber-reinforced composite material and fiber-reinforced composite material

Abstract

To provide a fiber structure for a fiber-reinforced composite material and a fiber-reinforced composite material, capable of suppressing reduction in strength of the fiber-reinforced composite material.SOLUTION: In a fiber structure for a fiber-reinforced composite material, a second yarn layer 22 located at a first end in a third direction Z has first auxiliary yarns 25 which extend in a second direction Y between weft yarns 24 adjoining in a first direction X, and are engaged with second binding yarns 32. The second yarn layer 22 located at a second end in the third direction Z has second auxiliary yarns 26 which extend in the second direction Y between the weft yarns 24 adjoining in the first direction X, and are engaged with first binding yarns 31. Outer diameters of the first binding yarn 31, the second binding yarn 32, the first auxiliary yarn 25, and the second auxiliary yarn 26 are smaller than outer diameters of a warp yarn 23 and the weft yarn 24. The first auxiliary yarn 25 and the second auxiliary yarn 26 pile up in the third direction Z.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Conventionally, fiber-reinforced composite materials in which a fiber structure is compounded in a matrix have been known. Patent Document 1 discloses a fiber structure including a laminate, a first binding yarn, and a second binding yarn.

[0003] The laminate has a first thread layer in which a plurality of first threads extending in a first direction are arranged in a second direction perpendicular to the first direction, and a second thread layer in which a plurality of second threads extending in the second direction are arranged in the first direction. The laminate is formed by stacking the first thread layer and the second thread layer in a third direction perpendicular to both the first and second directions. In the laminate, second thread layers are arranged on both ends in the third direction. The first threads and the second threads are reinforcing fiber threads.

[0004] The first and second binding threads are each disposed between adjacent first threads in the second direction. The first and second binding threads are each engaged with a plurality of second threads in the second thread layer located at both ends in the third direction. This bonds the first and second thread layers stacked in the third direction. The outer diameters of the first and second binding threads are smaller than the outer diameters of the first and second threads. In other words, the first and second binding threads are thinner than the first and second threads. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-106128 A Summary of the Invention [Problem to be solved by the invention]

[0006] When the second yarn is a reinforcing fiber yarn as in the above fiber structure, the coefficient of friction of the surface of the second yarn is relatively small, so that the second yarn is easily slippery with respect to the first and second binding yarns. In addition, when the first and second binding yarns are thinner than the second yarn, the binding force of the first and second binding yarns on the second yarn is weaker. Therefore, when the tension of the first and second binding yarns is different from that of the second binding yarn, the second yarn bound by the binding yarn with the weaker tension in the second yarn layer located at both ends in the third direction may shift in the first direction during weaving. When the second yarn shifts in the first direction, a gap is generated between the second yarns adjacent to each other in the first direction. When a fiber-reinforced composite material is manufactured using a fiber structure in which such gaps are generated, the strength of the fiber-reinforced composite material may be reduced due to the gaps. [Means for solving the problem]

[0007] A fiber structure for a fiber reinforced composite material for solving the above problems includes a laminate in which a first yarn layer in which a first reinforcing fiber yarn extending in a first direction is arranged in a second direction that is a direction perpendicular to the first direction and a second yarn layer in which a second reinforcing fiber yarn extending in the second direction is arranged in the first direction are laminated in a third direction that is a direction perpendicular to both the first direction and the second direction, with the second yarn layer being located at both ends in the third direction; a first binding yarn that is disposed between the first reinforcing fiber yarns adjacent to each other in the second direction and engages with the second reinforcing fiber yarn of the second yarn layer located at a first end in the third direction; and a second binding yarn that is disposed between the first reinforcing fiber yarns adjacent to each other in the second direction and at an end opposite to the first end in the third direction. and a second bonding yarn engaged with the second reinforcing fiber yarn of the second yarn layer positioned at a second end, wherein the second yarn layer positioned at a first end in the third direction has a first auxiliary yarn extending in the second direction between the second reinforcing fiber yarns adjacent in the first direction and engaged with the second bonding yarn, and the second yarn layer positioned at the second end in the third direction has a second auxiliary yarn extending in the second direction between the second reinforcing fiber yarns adjacent in the first direction and engaged with the first bonding yarn, each of the first bonding yarn, the second bonding yarn, the first auxiliary yarn, and the second auxiliary yarn has an outer diameter smaller than each of the first reinforcing fiber yarn and the second reinforcing fiber yarn, and the first auxiliary yarn and the second auxiliary yarn overlap in the third direction.

[0008] In the second thread layer located at the first end in the third direction, a first auxiliary thread having an outer diameter smaller than the outer diameter of the second reinforcing fiber thread is provided between the second reinforcing fiber threads adjacent in the first direction. Therefore, the interval between the second reinforcing fiber threads adjacent in the first direction is narrower than when the second reinforcing fiber thread is provided at the position of the first auxiliary thread. In addition, in the second thread layer located at the second end in the third direction, a second auxiliary thread having an outer diameter smaller than the outer diameter of the second reinforcing fiber thread is provided between the second reinforcing fiber threads adjacent in the first direction. Therefore, the interval between the second reinforcing fiber threads adjacent in the first direction is narrower than when the second reinforcing fiber thread is provided at the position of the second auxiliary thread.

[0009] As a result, the relationship between the portions of the first bonding yarn that sandwich the second auxiliary yarn from both sides becomes closer to parallel, so that the second auxiliary yarn is less likely to shift in the first direction. Also, when the relationship between the portions of the first bonding yarn that sandwich the second auxiliary yarn from both sides becomes closer to parallel, the relationship between the portions of the first bonding yarn that sandwich the second reinforcing fiber yarn from both sides also becomes closer to parallel. Therefore, the second reinforcing fiber yarn of the second yarn layer located at the first end in the third direction is also less likely to shift in the first direction.

[0010] Similarly, the relationship between the portions of the second bonding yarn that sandwich the first auxiliary yarn from both sides approaches parallelism, so that the first auxiliary yarn is less likely to shift in the first direction. Also, when the relationship between the portions of the second bonding yarn that sandwich the first auxiliary yarn from both sides approaches parallelism, the relationship between the portions of the second bonding yarn that sandwich the second reinforcing fiber yarn from both sides also approaches parallelism. Therefore, the second reinforcing fiber yarn of the second yarn layer located at the second end in the third direction is also less likely to shift in the first direction.

[0011] Therefore, in the second yarn layers located at both ends in the third direction, gaps are unlikely to occur between the second reinforcing fiber yarns adjacent in the first direction, which makes it possible to suppress a decrease in strength of a fiber-reinforced composite material produced using the fiber structure for a fiber-reinforced composite material.

[0012] In the fiber structure for a fiber-reinforced composite material, the first reinforcing fiber yarn and the second reinforcing fiber yarn may each be a continuous yarn. In the above configuration, the strength of the fiber reinforced composite material is improved compared to a case in which the first reinforcing fiber yarn and the second reinforcing fiber yarn are each spun yarn.

[0013] In the fiber structure for a fiber-reinforced composite material, each of the first reinforcing fiber yarns and the second reinforcing fiber yarns may be a round yarn having a circular cross-sectional shape. In the above configuration, a special yarn feeding device that would be required when the first reinforcing fiber yarn and the second reinforcing fiber yarn are flat yarns with an elliptical cross-sectional shape is not required, so a normal yarn feeding device can be used during weaving.

[0014] In the fiber structure for a fiber-reinforced composite material, both the first binding yarn and the second binding yarn may be disposed between the first reinforcing fiber yarns adjacent to each other in the second direction. In the above configuration, compared to the case where the first bonding yarns and the second bonding yarns are arranged alternately in the second direction via the first reinforcing fiber yarns, the misalignment of the second reinforcing fiber yarns in the second yarn layers located at both ends in the third direction can be more effectively regulated.

[0015] In the fiber structure for a fiber-reinforced composite material, the first binding yarn, the second binding yarn, the first auxiliary yarn, and the second auxiliary yarn may each be a round yarn having a circular cross-sectional shape. In the above configuration, the proportion of the first reinforcing fiber yarn and the second reinforcing fiber yarn in the fiber reinforced composite material can be increased compared to when the first bonding yarn, the second bonding yarn, the first auxiliary yarn, and the second auxiliary yarn are each flat yarns having an elliptical cross-sectional shape.

[0016] The fiber-reinforced composite material for solving the above problems is a fiber-reinforced composite material in which a fiber structure is compounded in a matrix, and the fiber structure is a fiber structure for fiber-reinforced composite material as described in claim 1.

[0017] In the second thread layer located at the first end in the third direction, a first auxiliary thread having an outer diameter smaller than the outer diameter of the second reinforcing fiber thread is provided between the second reinforcing fiber threads adjacent in the first direction. Therefore, the interval between the second reinforcing fiber threads adjacent in the first direction is narrower than when the second reinforcing fiber thread is provided at the position of the first auxiliary thread. In addition, in the second thread layer located at the second end in the third direction, a second auxiliary thread having an outer diameter smaller than the outer diameter of the second reinforcing fiber thread is provided between the second reinforcing fiber threads adjacent in the first direction. Therefore, the interval between the second reinforcing fiber threads adjacent in the first direction is narrower than when the second reinforcing fiber thread is provided at the position of the second auxiliary thread.

[0018] As a result, the relationship between the portions of the first bonding yarn that sandwich the second auxiliary yarn from both sides becomes closer to parallel, so that the second auxiliary yarn is less likely to shift in the first direction. Also, when the relationship between the portions of the first bonding yarn that sandwich the second auxiliary yarn from both sides becomes closer to parallel, the relationship between the portions of the first bonding yarn that sandwich the second reinforcing fiber yarn from both sides also becomes closer to parallel. Therefore, the second reinforcing fiber yarn of the second yarn layer located at the first end in the third direction is also less likely to shift in the first direction.

[0019] Similarly, the relationship between the portions of the second bonding yarn that sandwich the first auxiliary yarn from both sides approaches parallelism, so that the first auxiliary yarn is less likely to shift in the first direction. Also, when the relationship between the portions of the second bonding yarn that sandwich the first auxiliary yarn from both sides approaches parallelism, the relationship between the portions of the second bonding yarn that sandwich the second reinforcing fiber yarn from both sides also approaches parallelism. Therefore, the second reinforcing fiber yarn of the second yarn layer located at the second end in the third direction is also less likely to shift in the first direction.

[0020] Therefore, in the second yarn layers located at both ends in the third direction, gaps are unlikely to occur between the second reinforcing fiber yarns adjacent in the first direction, which makes it possible to suppress a decrease in strength of the fiber reinforced composite material in which the fiber structure for a fiber reinforced composite material is compounded in the matrix. Effect of the Invention

[0021] According to the present invention, it is possible to suppress a decrease in strength of a fiber-reinforced composite material. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view showing a fiber-reinforced composite material according to an embodiment. [Diagram 2] FIG. 2 is a perspective view showing a fiber structure according to an embodiment. [Diagram 3] FIG. 2 is a cross-sectional view showing a fiber structure according to an embodiment. [Figure 4] FIG. 2 is a cross-sectional view showing a fiber structure according to an embodiment. [Diagram 5] FIG. 11 is a cross-sectional view showing a fiber structure in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, one embodiment of a fiber structure for a fiber-reinforced composite material and a fiber-reinforced composite material will be described with reference to Figs. 1 to 4. The fiber structure for a fiber-reinforced composite material is a fiber structure used in a fiber-reinforced composite material. Hereinafter, the "fiber structure for a fiber-reinforced composite material" will be simply referred to as the "fiber structure".

[0024] As shown in Fig. 1, a fiber reinforced composite material 10 is formed by incorporating a fiber structure 11 in a matrix 12. The fiber structure 11 is a reinforcing base material of the fiber reinforced composite material 10. The matrix 12 is, for example, an epoxy resin, which is a thermosetting resin.

[0025] As shown in FIG. 2, the fiber structure 11 includes a laminate 20, a plurality of first binding yarns 31, and a plurality of second binding yarns 32. <Laminate> The laminate 20 has one or more first yarn layers 21 and two or more second yarn layers 22. The fiber structure 11 of the present embodiment has two first yarn layers 21 and two second yarn layers 22.

[0026] The first thread layer 21 has warp threads 23 as first reinforcing fiber threads. The warp threads 23 extend linearly along the first direction X. A plurality of warp threads 23 are arranged in a second direction Y that is a direction perpendicular to the first direction X. That is, the first thread layer 21 is formed by arranging a plurality of warp threads 23 extending in the first direction X in the second direction Y. The second thread layer 22 has weft threads 24 as second reinforcing fiber threads. The weft threads 24 extend linearly along the second direction Y. A plurality of weft threads 24 are arranged in the first direction X.

[0027] The laminate 20 is formed by stacking the first thread layer 21 and the second thread layer 22 in a third direction Z, which is a direction perpendicular to both the first direction X and the second direction Y. The second thread layer 22 is disposed at both ends of the laminate 20 in the third direction Z. The laminate 20 of this embodiment is formed by stacking the second thread layer 22, the first thread layer 21, the first thread layer 21, and the second thread layer 22 in this order from a first end in the third direction Z to a second end located opposite to the first end. Therefore, the two second thread layers 22 of the laminate 20 of this embodiment are the second thread layers 22 located at both ends in the third direction Z.

[0028] The interval between adjacent warp threads 23 in the second direction Y is the same in each first thread layer 21. In the laminate 20, the position of the warp threads 23 in the second direction Y is the same in each first thread layer 21. Therefore, the warp threads 23 of each first thread layer 21 overlap in the third direction Z. Moreover, the interval between adjacent weft threads 24 in the first direction X is the same in each second thread layer 22. In the laminate 20, the position of the weft threads 24 in the first direction X is the same in each second thread layer 22. Therefore, the weft threads 24 of each second thread layer 22 overlap in the third direction Z.

[0029] The second yarn layer 22 located at the first end in the third direction Z has a plurality of first auxiliary yarns 25 in addition to a plurality of weft yarns 24. Each of the first auxiliary yarns 25 extends linearly along the second direction Y. The plurality of first auxiliary yarns 25 are arranged in the first direction X. The first auxiliary yarns 25 are disposed between adjacent weft yarns 24 in the first direction X. In other words, the second yarn layer 22 located at the first end in the third direction Z is formed by arranging the weft yarns 24 and the first auxiliary yarns 25 extending in the second direction Y alternately in the first direction X.

[0030] The second yarn layer 22 located at the second end in the third direction Z has a plurality of second auxiliary yarns 26 in addition to a plurality of weft yarns 24. Each of the second auxiliary yarns 26 extends linearly along the second direction Y. The plurality of second auxiliary yarns 26 are arranged in the first direction X. The second auxiliary yarns 26 are disposed between adjacent weft yarns 24 in the first direction X. In other words, the second yarn layer 22 located at the second end in the third direction Z is formed by arranging the weft yarns 24 and the second auxiliary yarns 26 extending in the second direction Y alternately in the first direction X.

[0031] The interval between the first auxiliary yarns 25 adjacent to each other in the first direction X in the second yarn layer 22 located at a first end in the third direction Z is the same as the interval between the second auxiliary yarns 26 adjacent to each other in the first direction X in the second yarn layer 22 located at a second end in the third direction Z. In the laminate 20, the position of the first auxiliary yarn 25 in the first direction X is the same as the position of the second auxiliary yarn 26 in the first direction X. Therefore, the first auxiliary yarn 25 and the second auxiliary yarn 26 overlap in the third direction Z.

[0032] <First binding thread> The multiple first bonding yarns 31 are arranged in the second direction Y. The first bonding yarns 31 are disposed between the warp yarns 23 adjacent to each other in the second direction Y.

[0033] As shown in FIG. 3, the first connecting yarn 31 has a plurality of first weft-yarn engaging portions 31a, a plurality of first auxiliary yarn engaging portions 31b, and a plurality of first connecting portions 31c. The first weft-yarn engaging portion 31a is a portion that is engaged with the weft 24 of the second yarn layer 22 located at the first end in the third direction Z. The first weft-yarn engaging portion 31a is formed by folding back the first connecting yarn 31 so as to pass outside the weft 24 of the second yarn layer 22 located at the first end in the third direction Z. The first auxiliary yarn engaging portion 31b is a portion that is engaged with the second auxiliary yarn 26 of the second yarn layer 22 located at the second end in the third direction Z. The first auxiliary yarn engaging portion 31b is formed by folding back the first connecting yarn 31 so as to pass outside the second auxiliary yarn 26 of the second yarn layer 22 located at the second end in the third direction Z. The first connection portion 31c is a portion that connects the first weft engaging portion 31a and the first auxiliary thread engaging portion 31b. The first connection portion 31c extends in the third direction Z between the weft 24 and the auxiliary threads 25, 26 adjacent to each other in the first direction X. In the first connecting thread 31, the first weft engaging portion 31a and the first auxiliary thread engaging portion 31b are alternately repeated via the first connection portion 31c. The first connecting thread 31 is engaged with a plurality of wefts 24 of the second thread layer 22 located at a first end in the third direction Z, and is engaged with a plurality of second auxiliary threads 26 of the second thread layer 22 located at a second position in the third direction Z.

[0034] <Second binding thread> 2, the multiple second binding threads 32 are arranged in the second direction Y. The second binding threads 32 are arranged between the warp threads 23 adjacent to each other in the second direction Y. In this embodiment, both the first binding threads 31 and the second binding threads 32 are arranged between the warp threads 23 adjacent to each other in the second direction Y.

[0035] As shown in FIG. 4, the second connecting thread 32 has a plurality of second weft engaging portions 32a, a plurality of second auxiliary thread engaging portions 32b, and a plurality of second connecting portions 32c. The second weft engaging portion 32a is a portion that is engaged with the weft 24 of the second thread layer 22 located at the second end in the third direction Z. The second weft engaging portion 32a is formed by folding back the second connecting thread 32 so as to pass outside the weft 24 of the second thread layer 22 located at the second end in the third direction Z. The second auxiliary thread engaging portion 32b is a portion that is engaged with the first auxiliary thread 25 of the second thread layer 22 located at the first end in the third direction Z. The second auxiliary thread engaging portion 32b is formed by folding back the second connecting thread 32 so as to pass outside the first auxiliary thread 25 of the second thread layer 22 located at the first end in the third direction Z. The second connection portion 32c is a portion that connects the second weft engaging portion 32a and the second auxiliary thread engaging portion 32b. The second connection portion 32c extends in the third direction Z between the weft 24 and the auxiliary threads 25, 26 adjacent to each other in the first direction X. In the second connecting thread 32, the second weft engaging portion 32a and the second auxiliary thread engaging portion 32b are alternately repeated via the second connection portion 32c. The second connecting thread 32 is engaged with a plurality of wefts 24 of the second thread layer 22 located at a second end in the third direction Z, and is engaged with a plurality of first auxiliary threads 25 of the second thread layer 22 located at a first position in the third direction Z.

[0036] The second yarn layer 22 located at the first end in the third direction Z and the second yarn layer 22 located at the second end in the third direction Z are bonded by a first bonding yarn 31 and a second bonding yarn 32. As a result, the two first yarn layers 21, which are yarn layers located between the second yarn layer 22 located at the first end in the third direction Z and the second yarn layer 22 located at the second end in the third direction Z, are also bonded. In other words, the first bonding yarn 31 and the second bonding yarn 32 bond the first yarn layer 21 and the second yarn layer 22 that constitute the laminate 20.

[0037] <Details of each thread> The warp yarns 23 and the weft yarns 24 are reinforcing fiber yarns. The reinforcing fibers in this embodiment are carbon fibers. The warp yarns 23 and the weft yarns 24 in this embodiment are continuous yarns. The warp yarns 23 and the weft yarns 24 in this embodiment are flat yarns having an elliptical cross-sectional shape. In this embodiment, the yarns used for the warp yarns 23 and the weft yarns 24 are the same yarns.

[0038] The first binding yarn 31 and the second binding yarn 32 of this embodiment are yarns made of phenoxy resin. The first binding yarn 31 and the second binding yarn 32 of this embodiment are spun yarns. The first binding yarn 31 and the second binding yarn 32 of this embodiment are round yarns having a circular cross-sectional shape. The outer diameters of the first binding yarn 31 and the second binding yarn 32 are smaller than the outer diameters of the warp yarn 23 and the weft yarn 24. In other words, the first binding yarn 31 and the second binding yarn 32 are thinner yarns than the warp yarn 23 and the weft yarn 24.

[0039] The first auxiliary yarn 25 of this embodiment is a spun yarn. The first auxiliary yarn 25 of this embodiment is a round yarn having a circular cross-sectional shape. The outer diameter of the first auxiliary yarn 25 is smaller than the outer diameters of the warp yarn 23 and the weft yarn 24. More specifically, the outer diameter of the first auxiliary yarn 25 is smaller than the minor diameters of the warp yarn 23 and the weft yarn 24. In other words, the first auxiliary yarn 25 is a thinner yarn than the warp yarn 23 and the weft yarn 24.

[0040] The outer diameter of the first auxiliary yarn 25 is preferably equal to or smaller than the outer diameter of the second binding yarn 32. "The outer diameter of the first auxiliary yarn 25 is equal to or smaller than the outer diameter of the second binding yarn 32" includes the case where the outer diameter of the first auxiliary yarn 25 is the same as the outer diameter of the second binding yarn 32 and the case where the outer diameter of the first auxiliary yarn 25 is smaller than the outer diameter of the second binding yarn 32. The outer diameter of the first auxiliary yarn 25 in this embodiment is the same as the outer diameter of the second binding yarn 32.

[0041] The material of the first auxiliary thread 25 is preferably the same as the material of the second binding thread 32. "The material of the first auxiliary thread 25 is the same as the material of the second binding thread 32" includes the case where the material of the first auxiliary thread 25 is the same as the material of the second binding thread 32. Also, "The material of the first auxiliary thread 25 is the same as the material of the second binding thread 32" includes the case where the material of the first auxiliary thread 25 is slightly different from the material of the second binding thread 32 within the range where the friction coefficient of the first auxiliary thread 25 with respect to the second binding thread 32 does not change when the materials of the first auxiliary thread 25 and the second binding thread 32 are the same. The first auxiliary thread 25 of this embodiment is a thread made of phenoxy resin. Therefore, in this embodiment, the material of the first auxiliary thread 25 is the same as the material of the second binding thread 32.

[0042] The second auxiliary yarn 26 of this embodiment is a spun yarn. The second auxiliary yarn 26 of this embodiment is a round yarn having a circular cross-sectional shape. The outer diameter of the second auxiliary yarn 26 is smaller than the outer diameters of the warp yarn 23 and the weft yarn 24. More specifically, the outer diameter of the second auxiliary yarn 26 is smaller than the minor diameters of the warp yarn 23 and the weft yarn 24. In other words, the second auxiliary yarn 26 is a thinner yarn than the warp yarn 23 and the weft yarn 24.

[0043] The outer diameter of the second auxiliary yarn 26 is preferably equal to or smaller than the outer diameter of the first binding yarn 31. "The outer diameter of the second auxiliary yarn 26 is equal to or smaller than the outer diameter of the first binding yarn 31" includes cases where the outer diameter of the second auxiliary yarn 26 is the same as the outer diameter of the first binding yarn 31 and cases where the outer diameter of the second auxiliary yarn 26 is smaller than the outer diameter of the first binding yarn 31. In this embodiment, the outer diameter of the second auxiliary yarn 26 is the same as the outer diameter of the first binding yarn 31.

[0044] The material of the second auxiliary thread 26 is preferably the same as the material of the first connecting thread 31. "The material of the second auxiliary thread 26 is the same as the material of the first connecting thread 31" includes the case where the material of the second auxiliary thread 26 is the same as the material of the first connecting thread 31. In addition, "The material of the second auxiliary thread 26 is the same as the material of the first connecting thread 31" also includes the case where the material of the second auxiliary thread 26 is slightly different from the material of the first connecting thread 31 within the range where the friction coefficient of the second auxiliary thread 26 with respect to the first connecting thread 31 does not change when the materials of the second auxiliary thread 26 and the first connecting thread 31 are the same. The second auxiliary thread 26 of this embodiment is a thread made of phenoxy resin. Therefore, in this embodiment, the material of the second auxiliary thread 26 is the same as the material of the first connecting thread 31.

[0045] In this embodiment, the yarns used for the first auxiliary yarn 25, the second auxiliary yarn 26, the first binding yarn 31, and the second binding yarn 32 are the same yarn. [Actions and Effects of the Present Embodiment] The operation and effects of this embodiment will be described.

[0046] (1) In the second yarn layer 22 located at the first end in the third direction Z, a first auxiliary thread 25 having an outer diameter smaller than that of the weft thread 24 is provided between the weft threads 24 adjacent to each other in the first direction X. Therefore, the interval between the weft threads 24 adjacent to each other in the first direction X is narrower than when the weft threads 24 are provided at the position of the first auxiliary thread 25. In addition, in the second yarn layer 22 located at the second end in the third direction Z, a second auxiliary thread 26 having an outer diameter smaller than that of the weft thread 24 is provided between the weft threads 24 adjacent to each other in the first direction X. Therefore, the interval between the weft threads 24 adjacent to each other in the first direction X is narrower than when the weft threads 24 are provided at the position of the second auxiliary thread 26.

[0047] As a result, the relationship of the first connecting parts 31c in the first connecting yarn 31 that sandwich the second auxiliary yarn 26 from both sides becomes closer to parallel, so that the second auxiliary yarn 26 is less likely to shift in the first direction X. Also, when the relationship of the first connecting parts 31c in the first connecting yarn 31 that sandwich the second auxiliary yarn 26 from both sides becomes closer to parallel, the relationship of the first connecting parts 31c that sandwich the weft yarn 24 from both sides also becomes closer to parallel. Therefore, the weft yarn 24 of the second yarn layer 22 located at the first end in the third direction Z is also less likely to shift in the first direction X.

[0048] Similarly, in the second bonding yarn 32, the relationship of the second connection parts 32c that sandwich the first auxiliary yarn 25 from both sides approaches parallelism, so that the first auxiliary yarn 25 is less likely to shift in the first direction X. Furthermore, when the relationship of the second connection parts 32c that sandwich the first auxiliary yarn 25 from both sides approaches parallelism, the relationship of the second connection parts 32c that sandwich the weft yarn 24 from both sides also approaches parallelism. Therefore, the weft yarn 24 of the second yarn layer 22 located at the second end in the third direction Z is also less likely to shift in the first direction X.

[0049] Therefore, in the second yarn layers 22 located at both ends in the third direction Z, gaps are less likely to occur between the weft yarns 24 adjacent to each other in the first direction X. As a result, a decrease in strength of the fiber reinforced composite material 10 produced using the fiber structure 11 can be suppressed.

[0050] (2) The first auxiliary yarn 25 and the second auxiliary yarn 26 overlap in the third direction Z. This makes it easier for the weft yarn 24 of the second yarn layer 22 located at a first end in the third direction Z and the weft yarn 24 of the second yarn layer 22 located at a second end in the third direction Z to also overlap in the third direction Z. This makes it possible to bring the performance of the fiber-reinforced composite material 10 closer to the designed performance.

[0051] (3) The warp yarns 23 and the weft yarns 24 are each continuous yarns. Therefore, the strength of the fiber-reinforced composite material 10 is improved compared to when the warp yarns 23 and the weft yarns 24 are each spun yarns. (4) Both the first binding yarn 31 and the second binding yarn 32 are arranged between adjacent warp yarns 23 in the second direction Y. Therefore, compared to a case in which the first binding yarns 31 and the second binding yarns 32 are arranged alternately in the second direction Y via the warp yarns 23, the shifting of the weft yarns 24 in the second yarn layers 22 located at both ends in the third direction Z can be more effectively restricted.

[0052] (5) The first binding yarn 31, the second binding yarn 32, the first auxiliary yarn 25, and the second auxiliary yarn 26 are each round yarn. Therefore, the proportion of the warp yarns 23 and the weft yarns 24 in the fiber reinforced composite material 10 can be increased compared to when the first binding yarn 31, the second binding yarn 32, the first auxiliary yarn 25, and the second auxiliary yarn 26 are each flat yarn.

[0053] (6) The material of the first auxiliary thread 25 is the same as the material of the second binding thread 32. Therefore, compared to when the material of the first auxiliary thread 25 is different from the material of the second binding thread 32, the shifting of the first auxiliary thread 25 can be more effectively regulated. In addition, the material of the second auxiliary thread 26 is the same as the material of the first binding thread 31. Therefore, compared to when the material of the second auxiliary thread 26 is different from the material of the first binding thread 31, the shifting of the second auxiliary thread 26 can be more effectively regulated.

[0054] (7) The outer diameter of the first auxiliary yarn 25 is equal to or smaller than the outer diameter of the second binding yarn 32. Therefore, compared to when the outer diameter of the first auxiliary yarn 25 is larger than the outer diameter of the second binding yarn 32, the shifting of the first auxiliary yarn 25 can be more effectively regulated. In addition, the outer diameter of the second auxiliary yarn 26 is equal to or smaller than the outer diameter of the first binding yarn 31. Therefore, compared to when the outer diameter of the second auxiliary yarn 26 is larger than the outer diameter of the first binding yarn 31, the shifting of the second auxiliary yarn 26 can be more effectively regulated.

[0055] (8) The multiple first auxiliary yarns 25 are disposed in the second yarn layer 22 located at the first end in the third direction Z. Therefore, in the second yarn layer 22 located at the first end in the third direction Z, the gap between the weft yarns 24 adjacent to each other in the first direction X can be reduced. Therefore, the deviation of the weft yarns 24 of the second yarn layer 22 located at the first end in the third direction Z can be more effectively restricted. In addition, the multiple second auxiliary yarns 26 are disposed in the second yarn layer 22 located at the second end in the third direction Z. In this case, in the second yarn layer 22 located at the second end in the third direction Z, the gap between the weft yarns 24 adjacent to each other in the first direction X can be reduced. Therefore, the deviation of the weft yarns 24 of the second yarn layer 22 located at the first end in the third direction Z can be more effectively restricted.

[0056] (9) The same yarn is used for each of the warp yarn 23 and the weft yarn 24. The same yarn is used for each of the first auxiliary yarn 25, the second auxiliary yarn 26, the first binding yarn 31, and the second binding yarn 32. Therefore, the fiber structure 11 can be manufactured by simply preparing two types of yarn.

[0057] [Example of change] The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0058] The warp yarns 23 and the weft yarns 24 may be spun yarns as long as they are reinforced fiber yarns. The warp yarns 23 and the weft yarns 24 do not have to be flat yarns so long as they are reinforcing fiber yarns. For example, as shown in Fig. 5, the warp yarn 23 and the weft yarn 24 may each be a round yarn. In this case, a special yarn feeding device that is required when the warp yarn 23 and the weft yarn 24 are flat yarns is not required, so a normal yarn feeding device can be used during weaving. Note that a normal yarn feeding device refers to, for example, a color selector device of a rapier loom or a main nozzle of an air jet loom.

[0059] The cross-sectional shape of the warp threads 23 may be different from that of the weft threads 24. Furthermore, the cross-sectional shapes of the warp threads 23 and the weft threads 24 are not limited to an elliptical shape or a circular shape. Both the first binding yarn 31 and the second binding yarn 32 do not have to be arranged between adjacent warp yarns 23 in the second direction Y. For example, the first binding yarn 31 and the second binding yarn 32 may be arranged alternately in the second direction Y with the warp yarns 23 interposed therebetween.

[0060] The first binding yarn 31 and the second binding yarn 32 do not have to be round yarns. For example, the first binding yarn 31 and the second binding yarn 32 may be flat yarns. The cross-sectional shape of the first binding yarn 31 and the cross-sectional shape of the second binding yarn 32 may be different. The cross-sectional shapes of the first binding yarn 31 and the second binding yarn 32 are not limited to a circular shape or an elliptical shape.

[0061] The outer diameter of the first auxiliary yarn 25 may be larger than the outer diameter of the second binding yarn 32 as long as it is smaller than the outer diameters of the warp yarn 23 and the weft yarn 24 . The outer diameter of the second auxiliary yarn 26 may be larger than the outer diameter of the first binding yarn 31 as long as it is smaller than the outer diameters of the warp yarn 23 and the weft yarn 24 .

[0062] The first auxiliary thread 25 and the second auxiliary thread 26 do not have to be round threads. For example, the first auxiliary thread 25 and the second auxiliary thread 26 may be flat threads. The cross-sectional shape of the first auxiliary thread 25 and the cross-sectional shape of the second auxiliary thread 26 may be different. The cross-sectional shapes of the first auxiliary thread 25 and the second auxiliary thread 26 are not limited to a circular shape or an elliptical shape.

[0063] The matrix 12 is not limited to epoxy resin. The matrix 12 may be other thermosetting resins such as vinyl ester resin, unsaturated polyester resin, phenol resin, etc. The matrix 12 may also be thermoplastic resins such as polyamide, polybutylene terephthalate, polycarbonate, polyethylene, polypropylene, polyimide resin, ABS resin, etc.

[0064] The reinforcing fibers are not limited to carbon fibers, and may be glass fibers, silicon carbide ceramic fibers, aramid fibers, ultra-high molecular weight polyethylene fibers, or the like. The material of the first binding thread 31, the second binding thread 32, the first auxiliary thread 25, and the second auxiliary thread 26 is not limited to phenoxy resin. The material of the first binding thread 31, the second binding thread 32, the first auxiliary thread 25, and the second auxiliary thread 26 may be, for example, nylon.

[0065] The material of the first auxiliary threads 25 does not have to be the same as the material of the second binding threads 32 . The material of the second auxiliary threads 26 does not have to be the same as the material of the first binding threads 31 . The laminate 20 does not have to be formed of two first yarn layers 21 and two second yarn layers 22, so long as it is formed of one or more first yarn layers 21 and two or more second yarn layers 22. However, the second yarn layers 22 are positioned at both ends of the laminate 20 in the third direction Z.

[0066] For example, the laminate 20 may be one in which two first yarn layers 21 and three second yarn layers 22 are alternately laminated in the third direction Z. In this case, the laminate 20 has second yarn layers 22 positioned between the first yarn layers 21 in the third direction Z in addition to the second yarn layers 22 positioned at both ends in the third direction Z. The second yarn layers 22 positioned between the first yarn layers 21 in the third direction Z may not have multiple auxiliary yarns 25. In other words, the second yarn layers 22 positioned between the first yarn layers 21 in the third direction Z may be formed only by multiple weft yarns 24.

[0067] The interval between the auxiliary threads 25, 26 in the first direction X can be changed to adjust the interval between the weft threads 24 in the first direction X. Specifically, the interval between the auxiliary threads 25, 26 in the first direction X can be increased to increase the interval between the weft threads 24 in the first direction X. The interval between the auxiliary threads 25, 26 in the first direction X can be decreased to decrease the interval between the weft threads 24 in the first direction X. [Explanation of symbols]

[0068] Reference Signs List 10...fiber reinforced composite, 11...fiber structure as fiber structure for fiber reinforced composite, 12...matrix, 20...laminate, 21...first yarn layer, 22...second yarn layer, 23...warp yarn as first reinforcing fiber yarn, 24...weft yarn as second reinforcing fiber yarn, 25...first auxiliary yarn, 26...second auxiliary yarn, 31...first bonding yarn, 32...second bonding yarn, X...first direction, Y...second direction, Z...third direction.

Claims

1. a laminate in which a first yarn layer in which a plurality of first reinforcing fiber yarns extending in a first direction are arranged in a second direction perpendicular to the first direction, and a second yarn layer in which a plurality of second reinforcing fiber yarns extending in the second direction are arranged in the first direction are laminated in a third direction perpendicular to both the first direction and the second direction, and the second yarn layer is located at both ends in the third direction; a first binding yarn disposed between the first reinforcing fiber yarns adjacent to each other in the second direction and engaged with the second reinforcing fiber yarn of the second yarn layer located at a first end in the third direction; a second binding yarn disposed between the first reinforcing fiber yarns adjacent to each other in the second direction and engaged with the second reinforcing fiber yarn of the second yarn layer located at a second end opposite to the first end in the third direction; Equipped with The second yarn layer located at a first end in the third direction has a first auxiliary yarn extending in the second direction between the second reinforcing fiber yarns adjacent to each other in the first direction and engaged with the second binding yarn, The second yarn layer located at a second end in the third direction has a second auxiliary yarn extending in the second direction between the second reinforcing fiber yarns adjacent to each other in the first direction and engaged with the first binding yarn, The outer diameters of the first binding yarn, the second binding yarn, the first auxiliary yarn, and the second auxiliary yarn are smaller than the outer diameters of the first reinforcing fiber yarn and the second reinforcing fiber yarn, A fiber structure for a fiber-reinforced composite material, characterized in that the first auxiliary yarn and the second auxiliary yarn overlap in the third direction.

2. The fiber structure for a fiber-reinforced composite material according to claim 1 , wherein the first reinforcing fiber yarn and the second reinforcing fiber yarn are each a continuous yarn.

3. The fiber structure for a fiber-reinforced composite material according to claim 1 , wherein the first reinforcing fiber yarn and the second reinforcing fiber yarn are round yarns each having a circular cross-sectional shape.

4. The fiber structure for fiber-reinforced composite materials according to claim 1 , wherein both the first bonding yarn and the second bonding yarn are arranged between the first reinforcing fiber yarns adjacent to each other in the second direction.

5. The fiber structure for a fiber-reinforced composite material according to claim 1 , wherein the first binding yarn, the second binding yarn, the first auxiliary yarn, and the second auxiliary yarn are each a round yarn having a circular cross-sectional shape.

6. A fiber-reinforced composite material comprising a fiber structure in a matrix, the fiber structure being the fiber structure for fiber-reinforced composite material according to claim 1.

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