Fiber structures and fiber-reinforced composites

Abstract

To provide a fiber structure and a fiber-reinforced composite material capable of achieving cost reduction.SOLUTION: A fiber structure 10 comprises a first fiber substrate 11 having a body part 30 and a bifurcate part 40 and a second fiber substrate 80. The second fiber substrate 80 covers the bifurcate part 40. The bifurcate part 40 has a first curved surface 42 separating from the second fiber substrate 80. A first fiber bundle 12 is formed by winding a covering thread 14 around a bundle of non-continuous fibers. The first curved surface 42 includes a portion where the covering thread 14 is wound with a wider space than in the body part 30.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] The fiber structure and fiber-reinforced composite material disclosed in Patent Document 1 include a first fiber base material, a second fiber base material, and a gap filling member. The first fiber base material has a main body portion in which a plurality of fiber layers are laminated, and a branch portion in which the main body portion is bifurcated along the lamination direction of the fiber layers. The second fiber base material covers the branch portion and is integrated with the first fiber base material. The gap filling member is filled in the gap defined by the branch portion and the second fiber base material. The gap is reinforced by the gap filling member filled in the gap. The gap filling member in Patent Document 1 is a fiber bundle of discontinuous fibers and is thus string-like. This simplifies the task of placing the gap filling member in the gap. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-30478 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the fiber structure and fiber-reinforced composite material of Patent Document 1 require a gap filling member, which increases the production costs. [Means for solving the problem]

[0005] The fiber structure for solving the above problem includes a first fiber base material having a main body portion formed by stacking a plurality of first fiber layers in which a plurality of first fiber bundles are arranged, and a branch portion extending from the main body portion and in which the stacked plurality of first fiber layers are branched into two branches, and a second fiber base material having second fiber bundles, wherein the second fiber base material covers the branch portion, and the branch portion has a curved surface separated from the second fiber base material, and the first fiber bundle is formed by winding a covering yarn around a bundle of discontinuous fibers, and the curved surface includes a portion where the interval at which the covering yarn is wound is wider than that of the main body portion.

[0006] As a result, in each first fiber bundle, the non-continuous fibers protrude as fluff from between the covering yarns wound at intervals. In the fiber structure, the branching portion is covered by the second fiber base material, thereby defining a gap between the branching portion and the second fiber base material. The curved surface of the branching portion is located in this gap. And, fluff protruding from the first fiber bundle is arranged in the gap. The curved surface includes a portion where the spacing between the covering yarns is wider than the portion forming the main body portion. Therefore, the amount of fluff protruding from the curved surface into the gap can be made larger than the amount of fluff protruding from the main body portion. As a result, in a fiber-reinforced composite material formed by impregnating the fiber structure with a matrix material, the gap can be reinforced by the fluff. Therefore, the labor and parts cost required for reinforcing the gap can be reduced, and the cost of the fiber structure can be reduced.

[0007] In addition, in the fiber structure, the arrangement direction of the first fiber bundles in the first fiber layer may be perpendicular to a direction along the main body portion and the branch portions. As a result, fluff is more likely to occur from the curved surfaces of the branch portions than from the main body portion.

[0008] In addition, in the fiber structure, the arrangement direction of the first fiber bundles in the first fiber layer may be aligned along a direction along the main body portion and the branch portions. As a result, for the first fiber bundle located on the curved surface of the branching portion, the interval between the covering yarns is made wider than that for the first fiber bundle located on the main body portion, but the interval may be made wider over the entire axial direction of the bundle of non-continuous fibers. In other words, for the first fiber bundle located on the curved surface of the branching portion, the interval can be made constant over the entire axial direction of the bundle of non-continuous fibers. Therefore, for the first fiber bundle located on the curved surface of the branching portion, it is not necessary to change the interval between the covering yarns along the axial direction of the bundle of non-continuous fibers.

[0009] The fiber-reinforced composite material for solving the above problem is a fiber-reinforced composite material formed by impregnating a fiber structure with a matrix material, and the fiber structure is a fiber structure described in any one of claims 1 to 3.

[0010] As a result, in each first fiber bundle, the non-continuous fibers protrude as fluff from between the covering yarns wound at intervals. In the fiber structure, the branching portion is covered by the second fiber base material, thereby defining a gap between the branching portion and the second fiber base material. The curved surface of the branching portion is located in this gap. And, fluff protruding from the first fiber bundle is arranged in the gap. The curved surface includes a portion where the spacing between the covering yarns is wider than the portion forming the main body portion. Therefore, the amount of fluff protruding from the curved surface into the gap can be made larger than the amount of fluff protruding from the main body portion. As a result, in a fiber reinforced composite material formed by impregnating a matrix material into a fiber structure, the gap can be reinforced by fluff. Therefore, the labor and parts cost for reinforcing the gap can be reduced, and the cost of the fiber reinforced composite material can be reduced. Effect of the Invention

[0011] According to the present invention, costs can be reduced. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing a fiber-reinforced composite material according to an embodiment. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 11 is a diagram showing another example of a fiber structure. [Figure 8] FIG. 4 is a perspective view showing another example of the first fiber layer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of a fiber structure and a fiber-reinforced composite material will be described with reference to the drawings. <Fiber reinforced composite materials> 1, a fiber-reinforced composite material 100 is formed by curing a matrix material 101 impregnated into a fiber structure 10. The matrix material 101 is, for example, a resin or a ceramic.

[0014] <Overall fiber structure> As shown in Fig. 2, the fiber structure 10 includes a first fiber base material 11 and a second fiber base material 80. The first fiber base material 11 is T-shaped. The second fiber base material 80 is flat. The second fiber base material 80 is connected to the first fiber base material 11 so as to cover a portion of the first fiber base material 11.

[0015] <First fiber base material> As shown in Fig. 3, the first fiber base material 11 includes a plurality of first fiber layers 20. The first fiber layers 20 are formed by arranging a plurality of first fiber bundles 12. The direction in which the plurality of first fiber bundles 12 are arranged in the first fiber layer 20 is defined as an arrangement direction X. The plurality of first fiber bundles 12 in the first fiber layer 20 are arranged and connected by connecting yarns 15 in the arrangement direction X such that the axial directions of the first fiber bundles 12 are aligned.

[0016] 5 and 6, the first fiber bundle 12 has non-continuous fibers 13 that are reinforcing fibers, and a covering yarn 14 wound around the non-continuous fibers 13. The length of the non-continuous fibers 13 is, for example, 30 to 40 mm. The covering yarn 14 is wound around the bundle of non-continuous fibers 13 such that adjacent covering yarns 14 are spaced apart from each other in the axial direction of the bundle of non-continuous fibers 13.

[0017] In the first fiber bundle 12, the non-continuous fibers 13 protrude as fluff 16 between the covering yarns 14 adjacent to each other in the axial direction of the bundle. The reinforcing fibers may be organic fibers or inorganic fibers, or may be different types of organic fibers, different types of inorganic fibers, or mixed fibers in which organic fibers and inorganic fibers are mixed. Examples of organic fibers include acrylic fibers, nylon fibers, polyester fibers, aramid fibers, poly-p-phenylene benzobisoxazole fibers, and ultra-high molecular weight polyethylene fibers, and examples of inorganic fibers include carbon fibers, glass fibers, and ceramic fibers. In this embodiment, the non-continuous fibers 13 are formed of carbon fibers. The covering yarn 14 may be made of, for example, reinforcing fibers, as long as it can wind a plurality of non-continuous fibers 13.

[0018] 1 and 2, the first fiber base material 11 is T-shaped. The first fiber base material 11 includes a flat main body portion 30 and a branch portion 40 extending from the main body portion 30 in the axial direction of the first fiber bundles 12 in the main body portion 30. The main body portion 30 is formed by laminating a plurality of first fiber layers 20 in which a plurality of first fiber bundles 12 are arranged.

[0019] In the main body 30, the direction in which the first fiber layer 20 is laminated is defined as a lamination direction Y1. The main body 30 has a first surface 31 on one side of both sides in the lamination direction Y1, and a second surface 32 on the other side.

[0020] The branched portion 40 is formed by bifurcating a plurality of first fiber layers 20 extending from the main body portion 30 and stacked in the axial direction of the first fiber bundles 12 in the main body portion 30. The branched portion 40 has two curved portions 41 and two horizontal portions 60. The two curved portions 41 are portions bent with respect to the main body portion 30. Each of the two curved portions 41 has a first curved surface 42 and a second curved surface 43. Each of the two first curved surfaces 42 is a surface extending from a position where the main body portion 30 starts to bifurcate into two. The two first curved surfaces 42 are curved so as to move away from each other as they move away from the main body portion 30. One of the two second curved surfaces 43 is a surface continuing to the first surface 31 of the main body portion 30, and the other second curved surface 43 is a surface continuing to the second surface 32 of the main body portion 30. The first curved surface 42 has a larger area than the second curved surface 43.

[0021] Each of the two horizontal portions 60 is flat. Each horizontal portion 60 extends from each curved portion 41 in the stacking direction Y1 of the main body portion 30. In the horizontal portion 60, the stacking direction of the first fiber layer 20 is defined as the stacking direction Y2. The horizontal portion 60 has a first surface 61 on one of both sides of the horizontal portion 60 in the stacking direction Y2 of the first fiber layer 20, and a second surface 62 on the other side.

[0022] The first curved surface 42 of each bent portion 41 is connected to a first surface 61 of the adjacent horizontal portion 60. The second curved surface 43 of each bent portion 41 is connected to a second surface 62 of the adjacent horizontal portion 60. In the first fiber base material 11, the axial direction of each of the first fiber bundles 12 extends in a direction along the main body portion 30, the curved portions 41, and the horizontal portion 60 of the first fiber base material 11. The direction along the main body portion 30, the curved portions 41, and the horizontal portion 60 is referred to as the extension direction Z. The arrangement direction X of the first fiber bundles 12 in the first fiber layer 20 is perpendicular to the direction along the main body portion 30, the curved portions 41, and the horizontal portion 60, i.e., the extension direction Z.

[0023] In the first fiber base material 11, a main body portion 30, a curved portion 41, and a horizontal portion 60 are continuously formed along the axial direction of the first fiber bundle 12. In other words, the main body portion 30, the curved portion 41, and the horizontal portion 60 are each formed by a part of the first fiber bundle 12.

[0024] <Second fiber base material> The second fiber base material 80 is formed by laminating a plurality of second fiber layers 90. In the second fiber base material 80, the direction in which the second fiber layers 90 are laminated is the lamination direction Y3. The second fiber layer 90 is formed by arranging a plurality of second fiber bundles 81. The second fiber bundles 81 are fiber bundles formed by bundling a plurality of reinforcing fibers. The reinforcing fibers forming the second fiber bundles 81 are similar to the reinforcing fibers forming the first fiber bundles 12. The plurality of second fiber bundles 81 of the second fiber layer 90 are connected by a connecting thread (not shown) so that the axial directions of the second fiber bundles 81 are aligned. The second fiber base material 80 has a first surface 82 on one of both sides of the second fiber layer 90 in the lamination direction Y3, and a second surface 83 on the other side.

[0025] <Details of the fiber structure> In the fiber structure 10, the branched portion 40 is covered by the second fiber base material 80 from the side opposite to the main body portion 30. The first curved surface 42 of each bent portion 41 and the first surface 61 of the horizontal portion 60 face the second surface 83 of the second fiber base material 80. Each of the first curved surfaces 42 of the two bent portions 41 is spaced apart from the second surface 83 of the second fiber base material 80.

[0026] As shown in FIG. 4, in all the first fiber bundles 12, the portion forming the curved portion 41 is defined as the first portion 12a. In addition, in all the first fiber bundles 12, the portion forming the main body portion 30 and the horizontal portion 60 is defined as the second portion 12b. The first portion 12a is a portion sandwiched between the second portions 12b. The curved portion 41 includes the first portion 12a as a portion on the first curved surface 42 where the interval at which the covering yarn 14 is wound is wider than that of the main body portion 30 and the horizontal portion 60. In this embodiment, all of the curved portions 41 are formed by the first portions 12a.

[0027] In all the first fiber bundles 12, the spacing between the covering yarns 14 in the first region 12a is wider than the spacing between the covering yarns 14 in the second region 12b. Therefore, the number of fluffs 16 of the non-continuous fibers 13 protruding from the first region 12a is greater than the number of fluffs 16 of the non-continuous fibers 13 protruding from the second region 12b. The length of the fluff 16 is, for example, 5 to 10 mm. Note that the length of the fluff 16 may be at least shorter than the length of the non-continuous fibers 13 constituting the first fiber bundle 12. Since the number of fluffs 16 is greater, the thickness of the first region 12a is thinner than that of the second region 12b.

[0028] Next, the operation of this embodiment will be described. In the fiber structure 10, the fluff 16 protruding from the first curved surface 42 is located in the gap 44 defined by the first curved surface 42 of each of the two curved portions 41 and the second surface 83 of the second fiber base material 80. In the fiber reinforced composite 100, the fluff 16 is contained in the matrix material 101 filled in the gap 44.

[0029] According to this embodiment, the following effects are obtained. (1) In each of the first fiber bundles 12, the non-continuous fibers 13 protrude as fluff 16 from between the covering yarns 14 wound at intervals. The fluff 16 protruding from the first fiber bundles 12 is disposed in the gaps 44 of the fiber structure 10. The first portion 12a forming the first curved surface 42 has a wider gap around which the covering yarns 14 are wound than the second portion 12b forming the main body portion 30 and the horizontal portion 60. Therefore, the amount of fluff 16 protruding from the first curved surface 42 into the gaps 44 can be made larger than the amount of fluff 16 protruding from the main body portion 30 and the horizontal portion 60. As a result, in the fiber reinforced composite material 100 formed by impregnating the fiber structure 10 with the matrix material 101, the gaps 44 can be reinforced by the fluff 16. Therefore, the labor and parts cost required for reinforcing the gaps 44 can be reduced, and the costs of the fiber structure 10 and the fiber reinforced composite material 100 can be reduced.

[0030] (2) The arrangement direction X of the first fiber bundles 12 in the first fiber layer 20 is perpendicular to the extension direction Z along which the main body 30, the curved portion 41, and the horizontal portion 60 extend. This makes it easier for the fuzz 16 to form on the first curved surface 42 than on the main body 30 and the horizontal portion 60. As a result, the labor required for reinforcing the gaps 44 and the component costs can be reduced.

[0031] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the spirit of the invention. For example, the following modifications may be made. 7 and 8, the arrangement direction X of the first fiber bundles 12 in the first fiber layer 20 may be along the direction along the main body portion 30 and the branching portion 40, that is, along the extending direction Z. The branching portion 40 extends from the main body portion 30 in the arrangement direction X of the first fiber bundles 12 in the main body portion 30. The first fiber bundles 12 forming the curved portion 41 will be referred to as curved portion fiber bundles 12c. The first fiber bundles 12 forming the main body portion 30 will be referred to as main body portion fiber bundles 12d. The first fiber bundles 12 forming the horizontal portion 60 will be referred to as horizontal portion fiber bundles 12e.

[0032] The intervals between the covering yarns 14 of the fiber bundles 12c for the curved portion, the fiber bundles 12d for the main portion, and the fiber bundles 12e for the horizontal portion are constant throughout their axial directions. The intervals between the covering yarns 14 of the fiber bundles 12c for the curved portion are wider than the intervals between the covering yarns 14 of the fiber bundles 12d for the main portion and the fiber bundles 12e for the horizontal portion.

[0033] The curved portion fiber bundle 12c forming the first curved surface 42 has a wider interval at which the covering yarn 14 is wound than the main body portion fiber bundle 12d forming the main body portion 30 and the horizontal portion fiber bundle 12e forming the horizontal portion 60. Therefore, the amount of fluff 16 protruding from the first curved surface 42 into the gap 44 can be made larger than the amount of fluff 16 protruding from the main body portion 30 and the horizontal portion 60. As a result, in the fiber reinforced composite material 100 formed by impregnating the fiber structure 10 with the matrix material 101, the gap 44 can be reinforced by the fluff 16. Therefore, the labor and parts cost required for reinforcing the gap 44 can be reduced, and the costs of the fiber structure 10 and the fiber reinforced composite material 100 can be reduced.

[0034] For the fiber bundle for a curved portion 12c, the intervals of the covering yarns 14 are made wider than those of the fiber bundle for a main portion 12d and the fiber bundle for a horizontal portion 12e, but it is sufficient to make the intervals wider over the entire axial direction of the bundle of non-continuous fibers 13. In other words, for the fiber bundle for a curved portion 12c, the intervals can be made constant over the entire axial direction of the bundle of non-continuous fibers 13. Therefore, for the fiber bundle for a curved portion 12c, it is not necessary to change the intervals of the covering yarns 14 along the axial direction of the bundle of non-continuous fibers 13. Therefore, for the fiber bundle for a curved portion 12c, the labor required for changing the intervals of the covering yarns 14 is reduced.

[0035] Of all the first fiber layers 20 of the first fiber base material 11, the spacing between the covering yarns 14 may be wider only in the first fiber layer 20 that forms the first curved surface 42. The spacing between the covering yarns 14 of the first fiber bundle 12 may be wider only in a part of the first region 12a rather than over the entire first region 12a.

[0036] In addition to the first curved surface 42, the main body portion 30 and the horizontal portion 60 may have portions where the covering threads 14 are spaced apart from one another. The second fiber bundles 81 of the second fiber base material 80 may be formed by winding a bundle of discontinuous fibers 13 with a covering yarn 14, similar to the first fiber bundles 12. Then, the fluff 16 may be caused to protrude from the second fiber bundles 81 of the second fiber base material 80 toward the gaps 44.

[0037] The second fiber base material 80 may be formed of a single second fiber layer 90 . The second fiber layer 90 may be a woven or knitted fabric formed by a plurality of second fiber bundles 81.

[0038] The second fiber base material 80 may be formed by stacking a plurality of second fiber layers 90 and bonding them in the stacking direction Y3 with interlayer bonding yarns. In the embodiment, the branched portion 40 extends from the main body portion 30 in the axial direction of the first fiber bundles 12 in the main body portion 30, but this is not limited thereto. For example, the branched portion 40 may extend from a portion of the main body portion 30 along the axial direction of the first fiber bundles 12. In this case, the first fiber layer 20 extends in a direction intersecting the axial direction of the first fiber bundles 12 in the main body portion 30, and the branched portion 40 extends from at least one of the first surface 31 and the second surface 32 of the main body portion 30. The branched portion 40 may extend not only from one portion of the main body portion 30 but also from a plurality of portions.

[0039] The branching portion 40 may be configured with only the curved portion 41 without the horizontal portion 60. In this case, the extension direction Z is a direction along the main body portion 30 and the curved portion 41. In this case, in the embodiment, the arrangement direction X of the first fiber bundles 12 in the first fiber layer 20 is perpendicular to the extension direction Z along the main body portion 30 and the curved portion 41. In the embodiment shown in Figs. 7 and 8, the arrangement direction X of the first fiber bundles 12 in the first fiber layer 20 is parallel to the extension direction Z along the main body portion 30 and the curved portion 41.

[0040] The first fiber bundle 12 may have a plurality of covering yarns 14 . The technical ideas that can be understood from the above-described embodiment and modified examples will be described. The second fiber base material is formed by laminating a plurality of the second fiber layers. [Explanation of symbols]

[0041] X...arrangement direction, Z...extension direction as a direction along the main body portion and the branch portion, 10...fibrous structure, 11...first fiber base material, 12...first fiber bundle, 13...discontinuous fiber, 14...covering yarn, 20...first fiber layer, 30...main body portion, 40...branch portion, 42...first curved surface, 80...second fiber base material, 81...second fiber bundle, 100...fiber reinforced composite material, 101...matrix material.

Claims

1. a main body portion including a plurality of first fiber layers each including a plurality of first fiber bundles arranged therein; A first fiber base material including a branched portion extending from the main body portion and branching the first fiber layers into two, A second fiber base material having a second fiber bundle, The second fiber base material covers the branched portion, The branched portion has a curved surface that is spaced apart from the second fiber base material, The first fiber bundle is formed by winding a covering yarn around a bundle of non-continuous fibers, In the first fiber bundle, a part of the non-continuous fibers protrudes as fluff between the covering yarns adjacent to each other in the axial direction of the bundle of non-continuous fibers, the curved surface includes a portion in which the amount of fluff is greater than the amount of fluff protruding from between adjacent covering yarns in the axial direction of the non-continuous fiber bundle in the main body portion due to the interval at which the covering yarn is wound being wider than that in the main body portion, A fiber structure, characterized in that the fluff protruding from the curved surface is located in a gap defined by the branch portion and the second fiber base material.

2. The fiber structure according to claim 1 , wherein the arrangement direction of the first fiber bundles in the first fiber layer is perpendicular to a direction along the main body portion and the branch portion.

3. The fiber structure according to claim 1 , wherein the first fiber bundles in the first fiber layer are arranged in a direction along the main body portion and the branch portions.

4. A fiber-reinforced composite material formed by impregnating a fiber structure with a matrix material, the fiber structure being the fiber structure according to any one of claims 1 to 3.

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