Fiber Structure

Abstract

To improve a strength of a fiber structure while suppressing an increase in weight and manufacturing cost.SOLUTION: In a first part 40, an average degree of entanglement between a weft thread 30 and a warp thread 31 is smaller than in a second part 41. According to this, meandering of each of the weft yarns 30 and the warp yarns 31 is suppressed in the first part 40. Therefore, a strength of the first part 40, which is more susceptible to distortion of a liner 21 than the second part 41, can be improved, and as a result, the strength of a fiber structure 20 can be improved. Therefore, in order to increase the strength of the fiber structure 20, for example, a thickness of the second part 41, which is less subject to distortion than the first part 40 and does not require increased strength, is not unnecessarily thickened, as is a case when an entire fiber-reinforced base material is thickened. As a result, a weight of the fiber structure 20 does not increase unnecessarily, and a manufacturing cost does not increase unnecessarily.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a fiber structure. [Background technology]

[0002] For example, Patent Document 1 discloses a fiber structure comprising a liner and a fiber-reinforced substrate covering the liner from the outside. The liner has a cylindrical body portion and a dome portion that is continuous with the body portion in an axial direction along the central axis of the body portion and that tapers toward the central axis. The fiber-reinforced substrate has first yarns and second yarns. The first yarns are arranged so that their main axis extends in the axial direction. The second yarns are arranged so that their main axis extends in the circumferential direction of the liner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6729472 Summary of the Invention [Problem to be solved by the invention]

[0004] Such a fiber structure may be used, for example, as a pressure vessel filled with hydrogen gas for fuel cell vehicles. When hydrogen gas is filled into the pressure vessel, internal pressure acts on the liner, applying a load to the liner. Because the magnitude and direction of the load applied differ between the body portion and the dome portion, distortion is likely to occur at the boundary between the body portion and the dome portion in the liner. When distortion is likely to occur at the boundary between the body portion and the dome portion in the liner, a first portion of the fiber-reinforced substrate, which is the boundary between the body portion and the dome portion and extends between the shoulder portion and the body portion of the liner and covers at least the boundary, is more susceptible to distortion of the liner than a second portion excluding the first portion. Distortion in the first portion of the fiber-reinforced substrate reduces the strength of the fiber structure.

[0005] Therefore, the strength of the fiber structure may be improved by increasing the thickness of the entire fiber-reinforced substrate. However, if the entire fiber-reinforced substrate is made thick, the thickness of the second portion of the fiber-reinforced substrate, which is less likely to distort than the first portion and does not require increased strength, also becomes unnecessarily thick. As a result, the weight of the fiber structure and the manufacturing costs increase unnecessarily. [Means for solving the problem]

[0006] A fiber structure for solving the above problem includes a liner having a cylindrical body portion and a dome portion that is continuous with the body portion in an axial direction along the central axis of the body portion and that tapers toward the central axis, and a fiber-reinforced substrate covering the liner from the outside, wherein the fiber-reinforced substrate has first yarns arranged so that their main axis direction extends in the axial direction, and second yarns arranged so that their main axis direction extends in a circumferential direction of the liner, and the fiber-reinforced substrate is a fiber structure composed of a first portion that is a boundary between the body portion and the dome portion, extending between a shoulder portion of the liner and the body portion and covering at least the boundary, and a second portion excluding the first portion, and the first portion has a smaller average degree of entanglement between the first yarns and the second yarns than the second portion.

[0007] Because the magnitude and direction of the load applied to the body portion and the dome portion differ, distortion is likely to occur at the boundary between the body portion and the dome portion in the liner. Therefore, in the fiber-reinforced substrate, the first region, which is the boundary between the body portion and the dome portion and extends between the shoulder portion and the body portion of the liner and covers at least the boundary, is more susceptible to distortion of the liner than the second region excluding the first region. Therefore, the average degree of entanglement between the first yarn and the second yarn in the first region is smaller than that in the second region. This suppresses meandering of the first yarn and the second yarn in the first region. Therefore, the strength of the first region, which is more susceptible to distortion of the liner than the second region, can be improved, resulting in an improved strength of the fiber structure. Therefore, unlike when the entire fiber-reinforced substrate is thickened to improve the strength of the fiber structure, the second region, which is less susceptible to distortion than the first region, does not become unnecessarily thick. As a result, there is no unnecessary increase in the weight of the fiber structure or in the manufacturing costs. As a result, the strength of the fiber structure can be improved while suppressing increases in weight and manufacturing costs.

[0008] A fiber structure for solving the above problem includes a liner having a cylindrical body portion and a dome portion that is continuous with the body portion in an axial direction along the central axis of the body portion and that tapers toward the central axis, and a fiber-reinforced substrate that covers the liner from the outside, wherein the fiber-reinforced substrate has first yarns arranged so that their main axis direction extends in the axial direction and second yarns arranged so that their main axis direction extends in a circumferential direction of the liner, and the fiber-reinforced substrate is a fiber structure composed of a first portion that is a boundary between the body portion and the dome portion, extending between a shoulder portion of the liner and the body portion and covering at least the boundary, and a second portion excluding the first portion, and the first portion is provided with a reinforcing member having reinforcing fibers arranged so that their main axis direction extends in the axial direction.

[0009] Because the magnitude and direction of the load applied to the trunk portion and the dome portion differ, distortion is likely to occur at the boundary between the trunk portion and the dome portion in the liner. Therefore, in the fiber-reinforced substrate, the first region, which is the boundary between the trunk portion and the dome portion and extends between the shoulder portion and the trunk portion of the liner and covers at least the boundary, is more susceptible to distortion of the liner than the second region excluding the first region. Therefore, a reinforcing member having reinforcing fibers arranged so that the main axis of the yarn extends in the axial direction of the central axis of the trunk portion is provided in the first region. This reinforcing member can improve the strength of the first region, which is more susceptible to distortion of the liner than the second region, thereby improving the strength of the fiber structure. Therefore, unlike when the entire fiber-reinforced substrate is thickened to improve the strength of the fiber structure, the second region, which is less susceptible to distortion than the first region, does not need to be thickened unnecessarily. As a result, there is no unnecessary increase in the weight of the fiber structure or in the manufacturing costs. As a result, the strength of the fiber structure can be improved while suppressing increases in weight and manufacturing costs.

[0010] In the above-described fiber structure, the reinforcing member may be a woven fabric. The reinforcing member made of a woven fabric is suitable as a configuration for improving the strength of the first section. In the above-described fiber structure, the reinforcing member may be a unidirectional prepreg.

[0011] The reinforcing member made of unidirectional prepreg is suitable as a configuration for improving the strength of the first section. In the above-mentioned fiber structure, the fiber-reinforced substrate may be a woven fabric.

[0012] In the above-described fiber structure, the fiber-reinforced substrate may be a braid. In the above fiber structure, the fiber-reinforced substrate may be formed by winding the first yarn and the second yarn around the liner by filament winding.

[0013] A fiber-reinforced substrate that is woven, braided, or formed by winding a first thread and a second thread around a liner by filament winding is suitable as a fiber-reinforced substrate configuration that covers the liner from the outside.

[0014] In the above fiber structure, it is preferable that the first yarn and the second yarn are not entangled in the first region. This makes it easier to suppress meandering of the first yarn and the second yarn in the first region than when the first yarn and the second yarn are entangled in the first region, which makes it easier to further improve the strength of the first region, which is more susceptible to the influence of distortion of the liner than the second region, and as a result, makes it easier to further improve the strength of the fiber structure.

[0015] In the above fiber structure, the first portion may further include an auxiliary yarn that entangles the first yarn and the second yarn. According to this, since the first yarn and the second yarn are entangled via the auxiliary yarn, even if the fiber-reinforced base material is a woven fabric, it is possible to easily suppress collapse of the structure of the first portion, and as a result, it is possible to easily further improve the strength of the first portion. [Effects of the Invention]

[0016] According to this invention, the strength of the fiber structure can be improved while suppressing increases in weight and manufacturing costs. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 2 is a cross-sectional view schematically showing the high-pressure tank according to the first embodiment. [Figure 2] FIG. 2 is a side view schematically showing the fiber structure. [Figure 3] FIG. 4 is a front view schematically showing a part of the second portion. [Figure 4] FIG. 3 is a front view schematically showing a part of the first portion. [Figure 5] FIG. 3 is a cross-sectional view schematically showing a part of the high-pressure tank. [Figure 6] FIG. 10 is a cross-sectional view schematically showing a high-pressure tank according to a second embodiment. [Figure 7] FIG. 3 is a cross-sectional view schematically showing a part of the high-pressure tank. [Figure 8] FIG. 10 is a cross-sectional view schematically showing a portion of a high-pressure tank according to another embodiment. [Figure 9] FIG. 10 is a cross-sectional view schematically showing a portion of a high-pressure tank according to another embodiment. [Figure 10] FIG. 10 is a side view schematically showing a fiber structure according to another embodiment. [Figure 11] FIG. 10 is a cross-sectional view schematically showing a portion of a high-pressure tank according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] (First embodiment) A first embodiment of a fiber structure will be described below with reference to Figs. 1 to 5. The fiber structure of the embodiment described below is used in a high-pressure tank, which is a pressure vessel. The high-pressure tank is mounted, for example, on a fuel cell vehicle powered by a fuel cell. Hydrogen gas, which is the fuel for the fuel cell, is stored in the high-pressure tank.

[0019] <Overall configuration of the fiber structure 20> As shown in Fig. 1, the high-pressure tank 10 is constructed by impregnating a fiber structure 20 with a matrix resin Ma. The fiber structure 20 includes an elongated hollow liner 21 and a fiber-reinforced substrate 22. The fiber-reinforced substrate 22 covers the liner 21 from the outside. By covering the liner 21 from the outside, the fiber-reinforced substrate 22 reinforces the liner 21. This ensures the pressure resistance (mechanical strength) of the high-pressure tank 10.

[0020] <Liner 21 Configuration> The liner 21 is made of resin. The direction in which the central axis L of the liner 21 extends is defined as the axial direction Y. The liner 21 has a cylindrical body portion 23. The central axis of the body portion 23 coincides with the central axis L of the liner 21. The liner 21 has dome portions 24 at both ends of the axial direction in which the central axis of the body portion 23 extends. The liner 21 has boundaries R that are boundaries between the body portion 23 and each dome portion 24. The boundaries R are located at positions where the outer diameter of the liner 21 begins to decrease in the direction from the body portion 23 toward the dome portions 24.

[0021] Each dome portion 24 is continuous with the body portion 23 in the axial direction of the body portion 23. Each dome portion 24 has a shape that tapers toward the central axis of the body portion 23. The axial direction of each dome portion 24 coincides with the axial direction of the liner 21. Each dome portion 24 has a first curved portion 24a, a straight portion 24b, and a second curved portion 24c. The first curved portion 24a is a portion that connects to the body portion 23. The first curved portion 24a extends between the boundary R and the straight portion 24b. A first end of the straight portion 24b is connected to the first curved portion 24a. A second end of the straight portion 24b is connected to the second curved portion 24c. Therefore, the straight portion 24b extends between the first curved portion 24a and the second curved portion 24c. The second curved portion 24c tapers from the second end of the straight portion 24b. The second curved portion 24c is connected to the base portion 25. The proportion of the dome portion 24 that is occupied by the first curved portion 24a is, for example, 50%.

[0022] In this embodiment, the entire first curved portion 24a of the dome portion 24 is the shoulder portion A1 of the liner 21. Here, the shoulder portion A1 of the dome portion 24 refers to the portion of the dome portion 24 that tapers in a curved shape from the boundary R. Also, the shoulder portion A1 of the dome portion 24 refers to the portion of the dome portion 24 from the boundary R to the center of the dome portion 24.

[0023] The liner 21 has a nozzle 25 at the tip of each dome portion 24. Each nozzle 25 protrudes axially outward from the corresponding dome portion 24. Each nozzle 25 is made of metal. For example, each nozzle 25 is made of stainless steel. Each nozzle 25 has a hole 26 that communicates with the space inside the liner 21. The liner 21 also has a valve 27 and a screw 28. The valve 27 is attached to the hole 26 of the nozzle 25 located at the first axial end 21a of the liner 21. The screw 28 is threaded into the hole 26 of the nozzle 25 located at the second axial end 21b of the liner 21.

[0024] <Configuration of fiber-reinforced substrate 22> As shown in Figures 2, 3, and 4, the fiber-reinforced substrate 22 has a plurality of weft yarns 30 as first yarns and a plurality of warp yarns 31 as second yarns. The plurality of weft yarns 30 are arranged so that the main yarn axis direction X1 extends in the axial direction of the body portion 23. The plurality of weft yarns 30 are arranged in the circumferential direction Z of the liner 21. A portion of the plurality of weft yarns 30 extends straight along the outer peripheral surface of the body portion 23, and the other portion extends curvedly along the outer peripheral surface of each dome portion 24. The cross-sectional shape of the weft yarns 30 is flat. The weft yarns 30 are fiber bundles formed by bundling a plurality of reinforcing fibers, which are continuous fibers. The reinforcing fibers are, for example, carbon fibers.

[0025] The multiple warp threads 31 are arranged so that the main thread axis direction X2 extends in the circumferential direction Z of the liner 21. The multiple warp threads 31 are arranged in the axial direction Y of the liner 21 and are arranged parallel to each other with respect to the body portion 23 and each dome portion 24. The cross-sectional shape of the warp threads 31 is flat. The warp threads 31 are fiber bundles formed by bundling multiple reinforcing fibers, which are continuous fibers. The reinforcing fibers are, for example, carbon fibers. The fiber-reinforced substrate 22 is a woven fabric.

[0026] In this way, the weft yarns 30 and the warp yarns 31 are arranged perpendicular to each other, and the main axis direction X1 of the weft yarns 30 is aligned with the axial direction Y of the liner 21, thereby reinforcing the liner 21 in the axial direction Y. The main axis direction X2 of the warp yarns 31 is aligned with the circumferential direction Z of the liner 21, thereby reinforcing the liner 21 in the radial direction.

[0027] <Configuration of the first portion 40 and the second portion 41> As shown in FIG. 1 , the fiber-reinforced substrate 22 is composed of a first region 40 and a second region 41. The first region 40 is a region at the boundary R between the body 23 and each dome 24, extending between the end of the dome 24 on the boundary R side and the body 23 and covering at least the boundary R. The second region 41 is a region excluding the first region 40. The first region 40 externally covers a region of the liner 21 extending from a portion of the body 23 to a portion of the dome 24 across the boundary R. Specifically, the first region 40 externally covers the body 23 and a portion of the first curved portion 24a of each dome 24. Therefore, the first region 40 extends between the shoulder A1 of the liner 21 and the body 23 and covers the boundary R.

[0028] The second section 41 has a straight section 42 and a curved section 43. The straight section 42 covers a portion of the body section 23 of the liner 21 from the outside. The straight section 42 connects the first sections 40 together. Each curved section 43 covers a part of the first curved section 24a closer to the body section 23, the entire second curved section 24c, and the entire straight section 24b from the outside.

[0029] 3 and 5, the second region 41 is formed by plain weaving the weft yarns 30 and the warp yarns 31. In the second region 41, the weft yarns 30 and the warp yarns 31 are entangled with each other.

[0030] As shown in FIGS. 4 and 5 , the first region 40 is formed by stacking a weft layer 45 formed of multiple weft yarns 30 and a warp layer 46 formed of multiple warp yarns 31. The first region 40 has a smaller average degree of entanglement between the weft yarns 30 and the warp yarns 31 than the second region 41. In this embodiment, the weft yarns 30 and the warp yarns 31 are not entangled in the first region 40. The "degree of entanglement" refers to the degree of entanglement between the weft yarns 30 and the warp yarns 31. The "entanglement" refers to the degree to which the weft yarns 30 and the warp yarns 31 intersect at right angles. The higher the degree of entanglement, the more entanglement between the weft yarns 30 and the warp yarns 31, and the lower the degree of entanglement, the less entanglement between the weft yarns 30 and the warp yarns 31. The "average degree of entanglement" refers to the degree of entanglement per unit volume. In this embodiment, the degree of entanglement throughout the first region 40 is constant.

[0031] The fiber-reinforced base material 22 of this embodiment is woven by switching the winding manner of the weft yarns 30 and warp yarns 31 around the liner 21 between the first region 40 and the second region 41. Therefore, the weave is changed between the first region 40 and the second region 41.

[0032] <Operation of the First Embodiment> Next, the operation of the first embodiment will be described. For example, when the high-pressure tank 10 is filled with hydrogen gas, internal pressure acts on the liner 21, applying a load to the liner 21. Because the magnitude and direction of the load applied differ between the body portion 23 and the dome portion 24, distortion is likely to occur at the boundary R between the body portion 23 and the dome portion 24 in the liner 21. For this reason, in the fiber-reinforced substrate 22, the first portion 40, which is at the boundary R between the body portion 23 and the dome portion 24 and extends between the shoulder portion A1 of the liner 21 and the body portion 23 and covers the area including the boundary R, ​​is more susceptible to distortion of the liner 21 than the second portion 41 excluding the first portion 40.

[0033] Therefore, in this embodiment, the average degree of entanglement between the weft yarns 30 and the warp yarns 31 is set to be smaller in the first region 40 than in the second region 41. As a result, meandering of the weft yarns 30 and the warp yarns 31 is more easily suppressed in the first region 40. Therefore, the strength of the first region 40, which is more susceptible to the influence of distortion of the liner 21 than the second region 41, is improved. Therefore, the strength of the fiber structure 20 is improved. As a result, even when the high-pressure tank 10 is filled with hydrogen gas and internal pressure acts on the liner 21, the high-pressure tank 10 is less likely to deform.

[0034] <Advantages of the First Embodiment> The first embodiment can provide the following effects. (1-1) Because the magnitude and direction of the load applied to the body portion 23 and the dome portion 24 are different, distortion is likely to occur at the boundary R between the body portion 23 and the dome portion 24 in the liner 21. For this reason, in the fiber-reinforced substrate 22, the boundary R between the body portion 23 and the dome portion 24, i.e., the first region 40, which extends between the shoulder portion A1 of the liner 21 and the body portion 23 and covers the area including the boundary R, ​​is more susceptible to distortion of the liner 21 than the second region 41 excluding the first region 40. Therefore, the first region 40 is configured to have a smaller average degree of entanglement between the weft yarns 30 and the warp yarns 31 than the second region 41. This suppresses meandering of the weft yarns 30 and the warp yarns 31 in the first region 40. Therefore, the strength of the first region 40, which is more susceptible to distortion of the liner 21 than the second region 41, can be improved, resulting in an improved strength of the fiber structure 20. Consider, for example, a case where the entire fiber-reinforced substrate 22 is thickened to improve the strength of the fiber structure 20. In contrast, in the present embodiment, the thickness of the second region 41 of the fiber-reinforced substrate 22, which is less likely to distort than the first region 40 and does not require improvement in strength, is not unnecessarily increased. As a result, there is no unnecessarily increase in the weight of the fiber structure 20 or in the manufacturing costs. As described above, the strength of the fiber structure 20 can be improved while suppressing increases in weight and manufacturing costs.

[0035] (1-2) The fiber reinforced substrate 22 that is a woven fabric is suitable as the fiber reinforced substrate 22 for reinforcing the liner 21. (1-3) In the first region 40, the weft yarns 30 and the warp yarns 31 are not entangled. This makes it easier to suppress meandering of the weft yarns 30 and the warp yarns 31 in the first region 40 than when the weft yarns 30 and the warp yarns 31 are entangled in the first region 40. This makes it easier to further improve the strength of the first region 40, which is more susceptible to the influence of distortion of the liner 21 than the second region 41, and as a result, makes it easier to further improve the strength of the fiber structure 20.

[0036] (Second embodiment) A second embodiment of the fiber structure will be described below with reference to Figures 6 and 7. In the embodiment described below, the same components as those in the first embodiment will be denoted by the same reference numerals, and redundant description will be omitted or simplified.

[0037] As shown in Figures 6 and 7, each first region 40 is provided with a reinforcing member 50. The reinforcing member 50 is a sheet-like unidirectional prepreg. The reinforcing member 50 has reinforcing fibers F1 arranged to extend in the axial direction of the body portion 23. In Figure 7, the reinforcing fibers F1 are shown imaginarily by two-dot chain lines. Each reinforcing member 50 is arranged to be wound around the outer circumferential surface of the corresponding first region 40.

[0038] <Operation of the Second Embodiment> Next, the operation of the second embodiment will be described. The first region 40 is provided with a reinforcing member 50 having reinforcing fibers F1 arranged such that the main thread axis direction X1 extends in the axial direction along the central axis of the body portion 23. Therefore, the reinforcing member 50 improves the strength of the first region 40, which is more susceptible to the influence of distortion of the liner 21 than the second region 41. This improves the strength of the fiber structure 20. As a result, even when the high-pressure tank 10 is filled with hydrogen gas and internal pressure acts on the liner 21, the high-pressure tank 10 is less likely to deform.

[0039] <Effects of the second embodiment> The second embodiment can provide the following effects. (2-1) The first region 40 is provided with a reinforcing member 50 having reinforcing fibers F1 arranged such that the main yarn axis direction X1 extends in the axial direction along the central axis of the body portion 23. This reinforcing member 50 can improve the strength of the first region 40, which is more susceptible to distortion of the liner 21 than the second region 41. As a result, the strength of the fiber structure 20 can be improved. Consider, for example, a case in which the entire fiber-reinforced substrate 22 is made thicker to improve the strength of the fiber structure 20. In contrast, in the present embodiment, the thickness of the second region 41, which is less susceptible to distortion than the first region 40 and does not require strength improvement, is not unnecessarily increased. As a result, the weight of the fiber structure 20 and the manufacturing costs are not unnecessarily increased. As a result, the strength of the fiber structure 20 can be improved while suppressing increases in weight and manufacturing costs.

[0040] (2-2) The reinforcing member 50 made of unidirectional prepreg is suitable as a configuration for improving the strength of the first portion 40. <Example of change> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0041] As shown in FIG. 8, the reinforcing member 50 may be embedded inside the first portion 40, for example. 8, the reinforcing member 50 may be a woven fabric. In this case, for example, the reinforcing member 50 is formed by laminating a weft layer 51 formed of a plurality of weft threads 51a and a warp layer 52 formed of a plurality of warp threads 52a. The reinforcing fibers F1 forming the weft threads 30 are arranged so that the main yarn axis direction X1 extends in the axial direction of the body portion 23. In short, it is sufficient for the reinforcing member 50 to have reinforcing fibers F1 arranged so that the main yarn axis direction X1 extends in the axial direction of the body portion 23.

[0042] As shown in FIG. 9, the first region 40 may further include a first auxiliary yarn 60 and a second auxiliary yarn 61 as auxiliary yarns for intertwining the weft yarn 30 and the warp yarn 31 . According to this, since the weft yarns 30 and the warp yarns 31 are entangled via the first auxiliary yarns 60 and the second auxiliary yarns 61, even if the fiber-reinforced base material 22 is a woven fabric, it is possible to easily suppress collapse of the texture of the first region 40. As a result, it is possible to easily further improve the strength of the first region 40.

[0043] Furthermore, the first auxiliary yarns 60 and the second auxiliary yarns 61 are disposed between the weft yarns 30 and between the warp yarns 31, thereby creating gaps. With this, when the matrix resin Ma is impregnated into the fiber structure 20 by, for example, the RTM method, the matrix resin Ma impregnates through these gaps. This makes it easier to impregnate the fiber structure 20 with the matrix resin Ma.

[0044] As shown in Fig. 10, in the second embodiment, the fiber-reinforced substrate 22 may be, for example, a braid. In this case, the fiber-reinforced substrate 22 is composed of a weft yarn 30 and a first inclined yarn 71 and a second inclined yarn 72 as second yarns. A braided fiber-reinforced substrate 22 is suitable as a configuration of the fiber-reinforced substrate 22 that covers the liner 21 from the outside. In this case, the "degree of entanglement" refers to the degree of entanglement between the weft yarn 30 and the first inclined yarn 71 and the second inclined yarn 72. The "entanglement" refers to the entanglement of the weft yarn 30 and the first inclined yarn 71 and the second inclined yarn 72 with each other.

[0045] As shown in FIG. 11 , in the second embodiment, the fiber-reinforced substrate 22 may be formed by winding the weft yarn 30 and the warp yarn 31 around the liner 21 by filament winding. In this case, the fiber-reinforced substrate 22 has a weft-wound layer 80 around which the weft yarn 30 is wound by filament winding, and a warp-wound layer 81 around which the warp yarn 31 is wound by filament winding. The weft-wound layer 80 and the warp-wound layer 81 are alternately arranged. The reinforcing member 50 is arranged so as to be wound around the outer peripheral surface of the weft-wound layer 80 located in the outermost layer. The fiber-reinforced substrate 22 formed by winding the weft yarn 30 and the warp yarn 31 around the liner 21 by filament winding is suitable as the configuration of the fiber-reinforced substrate 22 that covers the liner 21 from the outside.

[0046] In the first embodiment, the first portion 40 may be provided with a reinforcing member. In the first embodiment, the second region 41 is formed by a plain weave, but this is not limited thereto. For example, the second region 41 may be formed by a twill weave or a multi-layer weave. In short, the weaving method of the fiber-reinforced substrate 22 is not particularly limited.

[0047] In the first embodiment, the weft yarns 30 and the warp yarns 31 may be entangled in the first region 40 as long as the average entanglement degree between the weft yarns 30 and the warp yarns 31 in the first region 40 is smaller than that in the second region 41. In short, it is sufficient that the average entanglement degree between the weft yarns 30 and the warp yarns 31 in the first region 40 is smaller than that in the second region 41. Furthermore, the entanglement degree in the first region 40 does not have to be constant. For example, the entanglement degree in the first region 40 may gradually decrease from the body portion 23 side toward the dome portion 24 side, or may gradually increase from the body portion 23 side toward the dome portion 24 side.

[0048] In each of the above embodiments, the second portion 41 may be constituted only by the curved portion 43. In this case, the first portion 40 may extend between the end of one dome portion 24 on the boundary R side and the end of the other dome portion 24 on the boundary R side. In short, the first portion 40 may be a portion that is at the boundary R between the body portion 23 and each dome portion 24, extends between the shoulder portion A1 of the liner 21 and the body portion 23, and covers at least the boundary R.

[0049] In each of the above embodiments, the dome portion 24 does not necessarily have to have the straight portion 24b. That is, the dome portion 24 may be composed of the first curved portion 24a and the second curved portion 24c. In this case, for example, the shoulder portion A1 of the liner 21 may be located between the boundary R and the boundary between the first curved portion 24a and the second curved portion 24c.

[0050] In each of the above embodiments, the shoulder portion A1 of the liner 21 does not have to have the straight portion 24b and the second curved portion 24c. In other words, the dome portion 24 may be composed of only the first curved portion 24a. In this case, the shoulder portion A1 of the liner 21 may be the portion of the first curved portion 24a from the boundary R to the center of the first curved portion 24a.

[0051] In each of the above-described embodiments, the first curved portion 24a may account for less than 50% of the dome portion 24. The key is that the first curved portion 24a may be configured to form the shoulder portion A1 of the liner 21.

[0052] In each of the above-described embodiments, the weft yarn 30 may be a fiber bundle formed by bundling a plurality of non-reinforced fibers. In each of the above-described embodiments, the warp yarns 31 may be fiber bundles formed by bundling a plurality of non-reinforced fibers.

[0053] In each of the above embodiments, the reinforcing fibers constituting the weft yarns 30 and the warp yarns 31 are not limited to carbon fibers. The reinforcing fibers constituting the weft yarns 30 and the warp yarns 31 may be other fibers generally considered to have high elasticity and high strength, such as glass fibers, silicon carbide ceramic fibers, aramid fibers, and ultra-high molecular weight polyethylene fibers.

[0054] In the above-described embodiments, the liner 21 is made of resin, but this is not limiting. The liner 21 may be made of, for example, aluminum. In the above embodiments, the high-pressure tank 10 is not limited to being mounted and used as a hydrogen source for a fuel cell-equipped electric vehicle. The high-pressure tank 10 may also be used as a hydrogen source for a hydrogen engine, a heat pump, or the like. The high-pressure tank 10 may also be used as a hydrogen source for a fuel cell in a household power supply. [Explanation of symbols]

[0055] 20...fiber structure, 21...liner, 22...fiber reinforced base material, 23...body portion, 24...dome portion, 30...weft yarn as first yarn, 31...warp yarn as second yarn, 40...first portion, 41...second portion, 50...reinforcing member, 60...first auxiliary yarn as auxiliary yarn, 61...second auxiliary yarn as auxiliary yarn, 71...first inclined yarn as second yarn, 72...second inclined yarn as second yarn, A1...shoulder portion, F1...reinforcing fiber, L...central axis, R...boundary, X1, X2...main yarn axis direction, Y...axial direction, Z...circumferential direction.

Claims

1. A cylindrical body portion; a liner having a dome portion that is continuous with the body portion in an axial direction along which a central axis of the body portion extends and that tapers toward the central axis; a fiber reinforced substrate that covers the liner from the outside, The fiber reinforced substrate is First yarns arranged so that their main axis direction extends in the axial direction; and second yarns arranged so that the yarn main axis direction extends in the circumferential direction of the liner, The fiber reinforced substrate is a first portion that extends across the boundary between the body portion and the dome portion, where the boundary is defined as a position where the outer diameter of the liner starts to decrease in a direction from the body portion toward the dome portion, and that covers at least the boundary; a second region excluding the first region, A fiber structure characterized in that the first region has a smaller average degree of entanglement between the first yarns and the second yarns than the second region.

2. The fiber structure according to claim 1 , wherein the first portion is provided with a reinforcing member having reinforcing fibers arranged such that a main axis of the yarn extends in the axial direction.

3. The fiber structure according to claim 2 , wherein the reinforcing member is a woven fabric.

4. The fiber structure according to claim 2 , wherein the reinforcing member is a unidirectional prepreg.

5. The fiber structure according to any one of claims 1 to 4, wherein the fiber-reinforced substrate is a woven fabric.

6. The fiber structure according to any one of claims 2 to 4, wherein the fiber-reinforced substrate is a braid.

7. The fiber structure according to any one of claims 2 to 4, characterized in that the fiber reinforced substrate is formed by winding the first yarn and the second yarn around the liner by filament winding.

8. The fiber structure according to claim 5 , wherein the first yarn and the second yarn are not entangled in the first region.

9. 9. The fiber structure according to claim 5, wherein the first portion further includes an auxiliary yarn that entangles the first yarn and the second yarn.

10. A fiber structure described in any one of claims 1 to 9, characterized in that the first portion covers the area from a portion of the body portion to a portion of the dome portion across the boundary.

11. The fiber structure according to any one of claims 1 to 10, characterized in that the second portion covers the dome portion except for at least a portion of the shoulder portion that is covered by the first portion.

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