Gas tank and method for manufacturing the same

Abstract

To provide a technique capable of improving strength of a fiber layer formed on an outer periphery of a liner of a gas tank and capable of improving an impregnation property of a resin material with respect to the fiber layer.SOLUTION: A gas tank includes: a liner having a cylindrical trunk and domes provided on both ends of the trunk; and a reinforcement layer covering an outer periphery of the liner. The reinforcement layer includes at least one first fiber layer having a first reinforcement in which fibers are wound in such a manner of being alternately woven on an outer periphery of the trunk, and at least one second fiber layer having a second reinforcement in which the fibers are wound at a predetermined angle with respect to a center axis of the liner on the outer periphery of the trunk.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present disclosure relates to a gas tank and a method for manufacturing the same.

Background Art

[0002] There is known a gas tank in which a fiber layer having a first reinforcing portion formed by winding reinforcing fibers in an alternate interlaced manner and a second reinforcing portion formed by winding reinforcing fibers helically so as to be continuous with the first reinforcing portion is laminated on the outer circumferential surface of a container body (for example, Patent Document 1). The gas tank is obtained by impregnating the laminated fiber layers with a thermosetting resin, followed by heating and curing.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by Invention

[0004] The second reinforcing portion where reinforcing fibers are wound helically may not be sufficiently impregnated with thermosetting resin due to its high fiber density.

Means for Solving Problem

[0005] The present disclosure can be implemented as the following modes. [Form 1] A gas tank comprising a liner having a cylindrical body and a pair of dome portions provided at both ends of the body, and a reinforcing layer covering the outer circumference of the liner, wherein the reinforcing layer comprises at least one first fiber layer having a first reinforcing portion on the outer circumference of the body, in which fibers are wound so as to be woven alternately, and at least one second fiber layer having a second reinforcing portion on the outer circumference of the body, in which fibers are wound at a predetermined angle with respect to the central axis of the liner, wherein the outermost layer of the reinforcing layer is the first fiber layer, the innermost layer of the reinforcing layer is the first fiber layer, the first fiber layer has the first reinforcing portion on the outer circumference of the body and the first reinforcing portion on the outer circumference of each of the dome portions, and the second fiber layer has the second reinforcing portion on the outer circumference of the body and the first reinforcing portion on the outer circumference of each of the dome portions. [Form 2] A gas tank according to Embodiment 1, wherein the reinforcing layer comprises alternating laminated sections in which the first fiber layer and the second fiber layer are alternately laminated. [Form 3] A gas tank according to Embodiment 1, wherein the reinforcing layer comprises a first continuous laminated section in which a plurality of the first fiber layers are continuously laminated, and a second continuous laminated section in which a plurality of the second fiber layers are continuously laminated. [Form 4] A gas tank according to Embodiment 3, wherein the first continuous stacked portion is located on the inner layer side of the reinforcing layer than the second continuous stacked portion. [Form 5] A gas tank according to Embodiment 1, wherein the number of first fiber layers included in the middle and inner layers of the reinforcing layer is greater than the number of first fiber layers included in the outer layers of the middle layer. [Form 6] The gas tank according to Embodiment 1, wherein the total thickness of the second fiber layer is 5 millimeters or less. [Form 7] A gas tank according to Embodiment 1, wherein the number of layers of the first fiber layer is greater than the number of layers of the second fiber layer. [Form 8] A gas tank according to Embodiment 1, wherein the first fiber layer is provided with the first reinforcing portion on the outer circumference of each dome portion, and the second fiber layer is provided with the second reinforcing portion on the outer circumference of each dome portion. Gas tank.

[0006] (1) According to one embodiment of the present disclosure, a gas tank is provided. The gas tank comprises a liner having a cylindrical body and dome portions provided at both ends of the body, and a reinforcing layer covering the outer circumference of the liner. The reinforcing layer comprises at least one first fiber layer having first reinforcing portions on the outer circumference of the body, in which fibers are wound so as to be woven alternately, and at least one second fiber layer having second reinforcing portions on the outer circumference of the body, in which fibers are wound at a predetermined angle with respect to the central axis of the liner. According to this form of gas tank, the strength of the gas tank can be improved by providing a second fiber layer to enhance the strength of the fiber layer, and the impregnation performance of the resin material into the fiber layer can be improved by providing a first fiber layer. (2) In the gas tank of the above form, the outermost layer of the reinforcing layer may be the first fiber layer. This form of gas tank can suppress or prevent disorder in the arrangement of fibrous material on the outer surface of the fibrous layer. (3) In the gas tank of the above form, the innermost layer of the reinforcing layer may be the first fiber layer. This form of gas tank makes it possible to suppress or prevent insufficient impregnation of the resin material in the innermost layer, where the resin material is difficult to impregnate. (4) In the gas tank of the above form, the reinforcing layer may include alternating laminated sections in which the first fiber layer and the second fiber layer are alternately laminated. According to this form of gas tank, the method of winding the fibrous material involves arranging different fiber layers alternately, thereby suppressing or preventing variations in shape throughout the reinforcing layer and reducing the strength of the gas tank. (5) In the gas tank of the above form, the reinforcing layer may include a first continuous laminated section in which a plurality of the first fiber layers are continuously laminated, and a second continuous laminated section in which a plurality of the second fiber layers are continuously laminated. This type of gas tank allows for a reduction in the number of times the method of winding the fibrous material needs to be changed, thereby improving the productivity of the gas tank. (6) In the gas tank of the above configuration, the first continuous stacked section may be located on the inner layer side of the reinforcing layer than the second continuous stacked section. According to this type of gas tank, by concentrating the first fiber layer, which is easily impregnated with resin material, on the inner layer side, the impregnation performance of the inner layer, which is less easily impregnated with resin material than the outer layer, can be improved. (7) In the gas tank of the above configuration, the number of first fiber layers included in the middle of the reinforcing layer and in the inner layer beyond the middle may be greater than the number of first fiber layers included in the outer layer beyond the middle. In this type of gas tank, by placing more first fiber layers on the inner layer side, where resin material is less likely to penetrate than on the outer layer side, the resin material can be more reliably impregnated all the way to the innermost layer. (8) In the gas tank of the above configuration, the total thickness of the second fiber layer may be 5 millimeters or less. This type of gas tank allows for more reliable impregnation of the resin material to the innermost layer during pressurized filling. (9) In the gas tank of the above configuration, the number of layers of the first fiber layer may be greater than the number of layers of the second fiber layer. This type of gas tank allows for more reliable impregnation of the resin material into the fiber layer. (10) In the gas tank of the above configuration, the first fiber layer and the second fiber layer may have the first reinforcing portion on the outer circumference of the dome portion. According to this form of gas tank, by forming a first reinforcing section on the outer circumference of the dome section which has curvature, it is possible to suppress the problem of the fiber material shifting from its intended position compared to when a second reinforcing section is formed on the outer circumference of the dome section. The present disclosure can also be implemented in various forms other than a gas tank and a method for manufacturing a gas tank. For example, the present disclosure can be implemented in forms such as a method for forming a fiber-reinforced resin layer, a method for manufacturing a fiber-reinforced plastic, an apparatus for manufacturing a fiber-reinforced plastic, an apparatus for manufacturing a gas tank, a method for controlling an apparatus for manufacturing a fiber-reinforced plastic, a computer program for implementing the control method, and a non-transitory recording medium that stores the computer program. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0007] [Figure 1] An explanatory view showing, in cross-section, the configuration of a gas tank according to a first embodiment of the present disclosure. [Figure 2] An explanatory view showing a base body including a first fiber layer on the outer circumference of a body portion. [Figure 3] An explanatory view showing, in an enlarged manner, a partial range of a first reinforcement portion. [Figure 4] A cross-sectional view showing the IV-IV position in FIG. 3. [Figure 5] An explanatory view showing a base body including a second fiber layer on the outer circumference of a body portion. [Figure 6] An explanatory view showing, in an enlarged manner, a partial range of a second reinforcement portion. [Figure 7] A cross-sectional view showing the VII-VII position in FIG. 6. [Figure 8] An explanatory view showing a schematic configuration of a gas tank manufacturing apparatus. [Figure 9] An explanatory view showing movement paths of a first supply unit and a second supply unit when performing helical winding. [Figure 10] An explanatory view showing movement paths of a first supply unit and a second supply unit when performing braiding winding. [Figure 11] An explanatory view schematically showing the configuration of a fiber-reinforced resin layer of a gas tank according to the first embodiment of the present disclosure. [Figure 12] An explanatory view schematically showing the configuration of a fiber-reinforced resin layer of a gas tank according to a second embodiment of the present disclosure. [Figure 13] An explanatory view showing another embodiment of the first reinforcement portion. [Figure 14] A cross-sectional view showing the XIV-XIV position in FIG. 13. [Modes for carrying out the invention]

[0008] A. First Embodiment: Figure 1 is an explanatory diagram showing a cross-sectional view of the configuration of a gas tank 100 as a first embodiment of the present disclosure. The gas tank 100 is a storage container for containing a high-pressure fluid of 10 to 70 MPa. The gas tank 100 can be formed in any shape, and in the example of Figure 1, the gas tank 100 has an elongated, substantially cylindrical external shape along its central axis AX.

[0009] The gas tank 100 is used, for example, to store hydrogen gas to supply to a vehicle fuel cell or a stationary fuel cell. The gas tank 100 comprises a liner 10, nozzles 16 and 17 positioned at both ends of the liner 10, and a fiber-reinforced resin layer 20 formed on the outer surfaces of the liner 10 and the nozzles 16 and 17. The gas tank 100 may contain not only hydrogen gas, but also various fluids such as oxygen and natural gas.

[0010] The liner 10 is a container having an internal space for sealing a fluid. The liner 10 is formed of a gas barrier resin such as nylon, polyamide, ethylene vinyl alcohol copolymer (EVOH), polyethylene, polypropylene, epoxy, or polystyrene. The liner 10 comprises a cylindrical body 12 and two hemispherical dome portions 14 positioned at both ends of the body 12 along the central axis AX. An opening is provided at the top of each dome portion 14. The boundary BD shown in Figure 1 is the connection point between the dome portion 14 and the body 12 of the liner 10, and is the position where the curvature of the outer shape of the liner 10 is zero. The liner 10 may be formed of metal instead of resin. The body 12 is not limited to a cylindrical shape, but may be any cylindrical shape with a polygonal cross-sectional shape.

[0011] The nozzles 16 and 17 are fitted into openings provided at the top of each dome portion 14 of the liner 10. The nozzle 16 is used, for example, to fill the gas tank 100 with gas or to release gas from the gas tank 100. The nozzle 17 is sealed and is used for centering during manufacturing, etc.

[0012] The fiber-reinforced resin layer 20 is a reinforcing layer for reinforcing the liner 10. The fiber-reinforced resin layer 20 is formed using fiber-reinforced plastics (FRP) to cover the outer circumference of the liner 10. In this embodiment, the fiber-reinforced resin layer 20 is formed by the so-called RTM (Resin Transfer Molding) method. Specifically, a substrate (also called a "fiber preform") with a fiber layer formed on the outer circumference of the liner 10 is prepared and placed in the mold. A "fiber layer" refers to a layer formed by winding a fiber material. As will be described later, the fiber layer has a structure in which multiple layers of two types of fiber layers, a first fiber layer L1 and a second fiber layer L2, are stacked in a predetermined order in the thickness direction. In addition to the liner 10, the fiber material may also be wound on the outer surfaces of the die caps 16 and 17.

[0013] In this embodiment, carbon fiber is used as the fiber material. In addition to carbon fiber, glass fiber, aramid fiber, boron fiber, high-strength polyethylene fiber, etc., can be used as the fiber material, and multiple types of these fibers may be combined. The number of fiber layers is, for example, about 10 to 20 layers, and can be arbitrarily set according to the size and shape of the gas tank 100. In this embodiment, the number of fiber layers is 11 layers.

[0014] The mold containing the substrate is closed, and the resin material is pressurized and filled into the closed mold at high speed and high pressure, thereby impregnating the fiber layer with the resin material. During the impregnation of the resin material, the inside of the substrate placed in the mold, i.e., the inside of the liner 10, is filled with an internal pressure, such as nitrogen gas, to withstand the external pressure applied by the resin material during impregnation. The gas tank 100 is completed by curing the resin material impregnated into the fiber layer.

[0015] Figure 2 is an explanatory diagram showing the external appearance of a base body having a first fiber layer L1 on the outer circumference of the body portion 12. The "first fiber layer" refers to a fiber layer having a first reinforcing portion 210 in the area RG2 that forms the outer circumference of the body portion 12. The "first reinforcing portion" refers to the part of the fiber layer formed by so-called braiding winding. "Braiding winding" refers to a method of winding fiber material so that it is woven in an alternating pattern.

[0016] As shown in Figure 2, in this embodiment, the first fiber layer L1 is provided with a first reinforcing portion 210 not only in the range RG2 but also in the range RG1 which is the outer circumference of the dome portion 14 of the liner 10. That is, the first fiber layer L1 is provided with a first reinforcing portion 210 on the outer circumference of the entire liner 10 by continuously forming the first reinforcing portion 210 over the ranges RG1 and RG2. The first fiber layer L1 is also called a "braiding-wound layer" because it is formed by braiding winding on the outer circumference of the entire liner 10.

[0017] Figure 3 is an explanatory diagram showing an enlarged view of a portion of the first reinforcing portion 210, AR1. Figure 4 is a cross-sectional view showing the position IV-IV in Figure 3. As shown in Figures 3 and 4, the fiber material has a strip-like appearance with a predetermined width WF of several millimeters, for example. However, the fiber material may be in any shape, such as thread-like or flat plate-like. The thickness of each fiber material can be set to any thickness of, for example, 0.5 millimeters or less. In this embodiment, the thickness of each fiber material is 0.3 millimeters.

[0018] As shown in Figure 3, the fiber material 211 is wound around the liner 10 at an angle θ1 that is an elevation angle with respect to the central axis AX. The fiber materials 212 to 215 are wound around the liner 10 at an angle θ2 that is a depression angle with respect to the central axis AX. The angles θ1 and θ2 can be set arbitrarily. It is preferable to set the angles θ1 and θ2 considering, for example, the stress acting on the body portion 12 of the liner 10. In this embodiment, in order to obtain a gas tank 100 with sufficient strength, the angle θ1 is set, for example, to approximately +54.7 degrees with respect to the central axis AX, and the angle θ2 is set, for example, to -54.7 degrees with respect to the central axis AX.

[0019] As shown in Figure 4, the first reinforcement section 210 is formed by weaving fiber material 211 and fiber materials 212-215 alternately on the inside and outside along the lamination direction. In this embodiment, the fiber material 211 is alternated every two fiber materials. The first reinforcement section 210 includes a layer L11 having the thickness of one fiber material and placed on the outside of the gas tank 100, and a layer L12 having the thickness of one fiber material and placed on the inside of the gas tank 100. The thickness of each layer of the first reinforcement section 210 is the thickness of two fiber materials. In the following description, the number of layers of the first fiber layer L1 is counted as "1 layer" when layers L11 and L12 are combined. In this embodiment, the thickness of the first reinforcement section 210 is 0.6 millimeters.

[0020] As shown in Figure 3, the first reinforcing section 210 is formed by weaving multiple fiber materials in an alternating pattern, resulting in a higher restraining force between the fiber materials compared to helical winding. Therefore, for example, the first reinforcing section 210 can suppress problems such as disordered arrangement of fiber materials and shifting from the intended position due to slippage of the fiber materials during winding, compared to the second reinforcing section 220.

[0021] As shown in Figure 3, in the first reinforcement section 210, gaps GP may occur between the woven fiber materials due to the alternating weaving of multiple fiber materials. Therefore, the resin material may be more easily impregnated in the first reinforcement section 210 compared to a fiber layer formed by tightly packed fiber materials, such as in a helical winding.

[0022] Figure 5 is an explanatory diagram showing the appearance of a base body having a second fiber layer L2 on the outer circumference of the body portion 12. The "second fiber layer" refers to a fiber layer having a second reinforcing portion 220 in the range RG2. The "second reinforcing portion" refers to the part of the fiber layer formed by so-called helical winding. "Helical winding" refers to a method of winding the fiber material around the outer circumference of the body portion 12 at a predetermined angle with respect to the central axis AX of the liner 10, and then winding it again at a predetermined angle with respect to the central axis AX.

[0023] As shown in Figure 5, in this embodiment, the second fiber layer L2 is provided with a first reinforcing portion 210 in the range RG1. According to the gas tank 100 of this embodiment, by forming the first reinforcing portion 210 on the outer circumference of the dome portion 14 which has curvature, it is possible to suppress the problem of the fiber material sliding and shifting from the intended position compared to helical winding. On the premise that a gas tank 100 with sufficient strength can be obtained, the second fiber layer L2 may have a second reinforcing portion 220 formed in the range RG1, or the fiber layer in the range RG1 may be omitted and the first reinforcing portion 210 may be formed only on the outer circumference of the body portion 12.

[0024] In the second fiber layer L2, the first reinforcing section 210 in area RG1 and the second reinforcing section 220 in area RG2 are formed continuously. Specifically, after forming the first reinforcing section 210 in one area RG1, the method of winding the fiber material is switched to form the second reinforcing section 220 in area RG2 continuously with the first reinforcing section 210. After forming the second reinforcing section 220, the first reinforcing section 210 is formed in the other area RG1 to complete the second fiber layer L2. The second fiber layer L2 is also called a "switched winding layer" because it is formed by switching the method of winding the fiber material between areas RG1 and RG2.

[0025] As shown near boundary BD in Figure 5, a predetermined width may occur in the axial direction from the starting position of the winding method switch to the completion position of the winding method switch, from the viewpoint of regularly arranging the fiber material. Here, "the switching position of the winding method of the fiber material in the axial direction" means a position in the axial direction that is midway between the starting position of the winding method switch and the completion position of the winding method switch. In the example in Figure 5, the switching position of the winding method from the first reinforcement part 210 to the second reinforcement part 220 is approximately coincided with boundary BD. Furthermore, a predetermined width may be set in the "switching position of the winding method of the fiber material in the axial direction" to allow for manufacturing errors, mechanical errors, etc. In this embodiment, the "switching position of the winding method of the fiber material in the axial direction" is further set to be included in boundary part BR, which allows for an error of a distance LW equal to two widths of the fiber material WF before and after the axial direction.

[0026] Figure 6 is an enlarged explanatory diagram showing the appearance of the second reinforcement section 220. Figure 6 shows an enlarged view of a portion of Figure 5, area AR2. As shown in Figure 6, the fiber material 221 is wound around the liner 10 at an angle θ3 that is an elevation angle with respect to the central axis AX. The fiber materials 222 to 225 are wound parallel to each other at an angle θ4 that is a depression angle with respect to the central axis AX. The angles θ3 and θ4 can be arbitrarily set, for example, by considering the stress acting on the body portion 12 of the liner 10. In this embodiment, the angles θ3 and θ4 are configured in the same way as the angles θ1 and θ2 described above.

[0027] Figure 7 is a cross-sectional view showing the position VII-VII in Figure 6. As shown in Figure 7, the second reinforcement section 220 has a layer L21 which is arranged on the outside of the gas tank 100, such as the fiber material 221, and a layer L22 which is arranged on the inside of the gas tank 100, such as the fiber materials 222-225. In the following description, the number of layers of the second fiber layer L2 is counted as "1 layer" when layers L21 and L22 are combined. In this embodiment, the thickness of the second reinforcement section 220 is 0.6 millimeters.

[0028] As shown in Figures 6 and 7, the second reinforcement section 220 is wound in a helical manner, with multiple fiber materials arranged parallel to each other and tightly bound together. As a result, the density of the fiber material is higher than that of braiding, and the strength of the gas tank 100 is increased. In the second reinforcement section 220, because the fiber materials are tightly bound together, when resin material is pressure-filled, for example by the RTM method, the resin material may be less likely to be impregnated than in the first reinforcement section 210.

[0029] Figure 8 is an explanatory diagram showing the schematic configuration of the manufacturing apparatus 300 for the gas tank 100. The manufacturing apparatus 300 is a device for winding fibrous material onto the liner 10. The manufacturing apparatus 300 includes a first supply unit 42 and a second supply unit 44 for supplying fibrous material, and a moving mechanism (not shown) for moving the liner 10 in the direction DRT. In Figure 8, for illustrative purposes, two first supply units 42 and two second supply units 44 are shown, but in reality, there are as many as correspond to the number of fibrous materials to be wound.

[0030] The manufacturing apparatus 300 rotates the first supply unit 42, which feeds out the fiber material 22A, and the second supply unit 44, which feeds out the fiber material 22B, along the movement paths OR1 and OR2 around the liner 10. The manufacturing apparatus 300 moves the liner 10 along the axial direction DRT, winding the fiber materials 22A and 22B around the outer circumference of one dome portion 14 of the liner 10, the outer circumference of the body portion 12, and the outer circumference of the other dome portion 14 in this order.

[0031] The manufacturing apparatus 300 can switch between different movement paths OR1 and OR2 depending on whether helical winding or braiding winding is being performed. In the example in Figure 8, the movement paths OR1 and OR2 when helical winding is being performed are shown.

[0032] Figure 9 is an explanatory diagram showing the movement paths OR1 and OR2 of the first supply unit 42 and the second supply unit 44 when helical winding is performed. The movement path OR1 of the first supply unit 42 is shown by a solid line, and the movement path OR2 of the second supply unit 44 is shown by a dashed line. The first supply unit 42 and the second supply unit 44 are arranged, for example, in two concentric movement paths OR1 and OR2 surrounding the central axis AX. Movement path OR1 is located further from the central axis AX than movement path OR2, i.e., radially outward. Note that movement paths OR1 and OR2 are not limited to concentric circles, but may be any shape of trajectory that can rotate around the central axis AX.

[0033] As shown in Figure 9, the movement direction DR1 of the first supply unit 42 on the movement path OR1 and the movement direction DR2 of the second supply unit 44 on the movement path OR2 are in opposite directions. As shown in Figure 8, the second supply unit 44, which rotates in the movement direction DR2, wraps multiple fiber materials 22B around the outer circumference of the liner 10 at an angle θ4 that is downward with respect to the central axis AX. The first supply unit 42, which rotates in the movement direction DR1, wraps multiple fiber materials 22A around the outside of the fiber materials 22B at an angle θ3 that is upward with respect to the central axis AX. As a result, a second reinforcement section 220 is formed on the outer circumference of the body section 12, with layer L21 on the outside and layer L22 on the inside.

[0034] Figure 10 is an explanatory diagram showing the movement paths OR1b and OR2b of the first supply unit 42 and the second supply unit 44 when performing braiding winding. To facilitate understanding of the technology, in Figure 10, the movement path OR1b of the first supply unit 42 is shown with a solid line, and the movement path OR2b of the second supply unit 44 is shown with a dashed line.

[0035] As shown in Figure 10, the movement direction DR1 of the first supply unit 42 on the movement path OR1b and the movement direction DR2 of the second supply unit 44 on the movement path OR2b are in opposite directions. In the movement paths OR1b and OR2b, the state in which the first supply unit 42 is on the radially inner side and the second supply unit 44 is on the radially outer side alternates with the state in which the second supply unit 44 is on the radially inner side and the first supply unit 42 is on the radially outer side. As a result, the fiber material 22B supplied at an angle θ2 that is downward with respect to the central axis AX and the fiber material 22A supplied at an angle θ1 that is upward with respect to the central axis AX are wrapped around the outer circumference of the liner 10 in an alternating pattern. As a result, a first reinforcing section 210 with layer L11 on the outside and layer L12 on the inside is formed on the outer circumference of the body section 12.

[0036] The manufacturing apparatus 300 can switch between movement paths OR1, OR2 and movement paths OR1b, OR2b at any timing with respect to the liner 10 moving in direction DRT. In this embodiment, when forming the second fiber layer L2, the manufacturing apparatus 300 performs braiding winding on the outer circumference of one dome portion 14 using movement paths OR1b, OR2b, and then, at the boundary portion BR shown in Figure 2, switches from movement paths OR1b, OR2b to movement paths OR1, OR2 to perform helical winding on the body portion 12. At the boundary portion BR between the body portion 12 and the other dome portion 14, the manufacturing apparatus 300 switches from movement paths OR1, OR2 to movement paths OR1b, OR2b to perform braiding winding on the other dome portion 14. When forming the first fiber layer L1, the manufacturing apparatus 300 performs braiding winding on the entire liner 10 without switching between movement paths OR1, OR2.

[0037] Figure 11 is a schematic diagram illustrating the structure of the fiber-reinforced resin layer 20 of a gas tank 100 according to the first embodiment of this disclosure. Table TB1 in Figure 11 corresponds to a cross-sectional view of the fiber-reinforced resin layer 20 in range RG2 and shows the arrangement relationship in the lamination direction of the first fiber layer L1 and the second fiber layer L2 on the outer circumference of the body portion 12 of the liner 10. The bottom row of Table TB1 is the liner 10, and below that is the inside of the gas tank 100. The top row of Table TB1 is the 11th layer of the fiber-reinforced resin layer 20, which is the outermost layer. The fiber layer laminated on the outer surface of the liner 10 is also called the "innermost layer". When the innermost layer is considered the 1st layer, the 2nd to 10th layers are also called the "internal layers".

[0038] As shown in Figure 11, in the gas tank 100 of this embodiment, the fiber-reinforced resin layer 20 has a first fiber layer L1 having a first reinforcing portion 210 formed by braiding winding, and a second fiber layer L2 having a second reinforcing portion 220 formed by helical winding. The inclusion of the second fiber layer L2 improves the strength of the gas tank 100, and the inclusion of the first fiber layer L1 facilitates the impregnation of the resin material into the fiber layer. Therefore, a gas tank 100 can be obtained that balances the suppression of insufficient impregnation of the resin material with the improvement of strength.

[0039] In the gas tank 100 of this embodiment, a first fiber layer L1 is arranged as the outermost layer of the fiber-reinforced resin layer 20. When resin material is pressurized and filled into a mold by the RTM method, the high-speed, high-pressure resin material collides with the fiber layer, which can cause problems such as disorder in the arrangement of the fiber material, or peeling and lifting of the fiber material. By arranging the first fiber layer L1, which has a high restraining force between the fiber materials, as the outermost layer, it is possible to suppress or prevent problems such as disorder in the arrangement of the fiber material on the outer surface of the fiber layer and peeling of the fiber material caused by collisions of resin material when impregnating the fiber layer with resin material.

[0040] In the gas tank 100 of this embodiment, a first fiber layer L1 is arranged in the innermost layer of the fiber-reinforced resin layer 20. The innermost layer of the fiber-reinforced resin layer 20 is susceptible to the effects of deformation of the liner 10, and the density of the fiber material tends to be higher in this layer compared to the inner fiber layers. Therefore, the innermost layer of the fiber-reinforced resin layer 20 may be less permeable to resin material compared to other layers. This characteristic is particularly pronounced when the liner 10 is made of resin. In this embodiment, by arranging a first fiber layer L1, which is easily permeable to resin material, in the innermost layer of the fiber-reinforced resin layer 20, insufficient impregnation of the resin material in the innermost layer can be suppressed or prevented.

[0041] In the gas tank 100 of this embodiment, the fiber-reinforced resin layer 20 is provided with alternating laminated sections. An "alternating laminated section" means a fiber layer having a plurality of first fiber layers L1 and a plurality of second fiber layers L2, in which the first fiber layers L1 and the second fiber layers L2 are alternately laminated. In this embodiment, the first fiber layers L1 and the second fiber layers L2 are alternately laminated one layer at a time. However, it is not limited to this, and the first fiber layers L1 and the second fiber layers L2 may be alternately laminated every two or more predetermined layers. The alternating laminated section may be included in any part of the fiber-reinforced resin layer 20, for example, it may be provided only in the inner layers, or it may include at least one of the innermost layer and the outermost layer. In this embodiment, the alternating laminated section is formed over all layers from the innermost layer to the outermost layer. According to the gas tank 100 of this embodiment, by alternately arranging fiber layers with different methods of winding the fiber material, variations in the overall shape of the fiber-reinforced resin layer 20 can be suppressed, and a decrease in the strength of the gas tank 100 can be suppressed or prevented.

[0042] In the gas tank 100 of this embodiment, the fiber-reinforced resin layer 20 is set so that the total thickness of the second fiber layer L2 is 5 millimeters or less. This value was experimentally obtained by the inventors using a gas tank 100 manufacturing apparatus that utilizes the RTM method to determine the relationship between the thickness of the second fiber layer L2 contained in the fiber-reinforced resin layer 20 and the impregnation of the resin material. Specifically, several substrate samples with different thicknesses of the second fiber layer L2 were prepared. The samples were placed in a mold of the manufacturing apparatus, and a two-component epoxy resin was used as the resin material and impregnated into the fiber layer of each sample by pressurized filling at a pressure of about 5 to 10 MPa. As a result, the maximum thickness of the second fiber layer L2 in the sample in which the resin material was impregnated up to the innermost layer of the fiber layer was 5 millimeters. However, in order to more reliably impregnate the resin material, in this embodiment, the total number of layers of the second fiber layer L2 is set to 5 layers or less, and as a result, the total thickness of the second fiber layer L2 is 3.0 millimeters or less. According to the gas tank 100 of this embodiment, when pressurizing the filling of resin material using the RTM method, the resin material can be more reliably impregnated to the innermost layer.

[0043] In the gas tank 100 of this embodiment, as shown in Figure 11, the fiber-reinforced resin layer 20 has six layers in the first fiber layer L1 and five layers in the second fiber layer L2. That is, the number of layers in the first fiber layer L1 in the fiber-reinforced resin layer 20 is set to be greater than the number of layers in the second fiber layer L2. Therefore, the resin material can be impregnated into the fiber layer more reliably.

[0044] B. Second Embodiment: Figure 12 is a schematic diagram illustrating the structure of the fiber-reinforced resin layer 20 of the gas tank 100 according to the second embodiment of this disclosure. The structure of Table TB2 shown in Figure 12 is the same as the structure of Table TB1 shown in Figure 11, so its explanation is omitted.

[0045] The gas tank 100 of the second embodiment, like the first embodiment, has a fiber-reinforced resin layer 20 that includes a first fiber layer L1 and a second fiber layer L2, making it possible to obtain a gas tank 100 that balances suppression of insufficient impregnation of the resin material with strength. Furthermore, the total thickness of the second fiber layer L2 is 3.0 millimeters or less, which allows for more reliable impregnation of the resin material to the innermost layer. In addition, to suppress or prevent insufficient impregnation of the resin material in the innermost layer, the first fiber layer L1 is arranged in the innermost layer of the fiber-reinforced resin layer 20, and to increase the strength of the outer surface of the fiber layer, the first fiber layer L1 is arranged in the outermost layer of the fiber-reinforced resin layer 20.

[0046] As shown in Table TB2, in this embodiment, the fiber-reinforced resin layer 20 is provided with a first continuous laminated section ST1 in which a plurality of first fiber layers L1 are continuously laminated, and a second continuous laminated section ST2 in which a plurality of second fiber layers L2 are continuously laminated. By arranging fiber layers with different fiber winding methods in succession, the number of times the fiber winding method needs to be switched can be reduced, thereby improving the productivity of the gas tank 100.

[0047] As shown in Table TB2, in the gas tank 100 of the second embodiment, the first continuous laminated section ST1 is formed by a first fiber layer L1 that is continuously laminated from the innermost layer to the fifth layer, and the second continuous laminated section ST2 is formed by a second fiber layer L2 that is continuously laminated from the sixth layer to the tenth layer. In this embodiment, in the fiber-reinforced resin layer 20, the first continuous laminated section ST1 is located on the inner layer side than the second continuous laminated section ST2. By concentrating the first fiber layer L1, which is easily impregnated by the resin material, on the inner layer side, the impregnation performance of the inner layer side, which is less easily impregnated by the resin material than the outer layer side, can be improved.

[0048] C. Other embodiments: (C1) In the first embodiment described above, the first fiber layer L1 is provided with a first reinforcing portion 210 in both the ranges RG1 and RG2 which form the dome portion 14 and the outer circumference of the body portion 12 of the liner 10. In contrast, assuming that the first fiber layer L1 is provided with a first reinforcing portion 210 in the range RG2, the range RG1 may be provided with a fiber layer formed in a manner other than the first reinforcing portion 210, such as a second reinforcing portion 220.

[0049] (C2) In the first embodiment described above, as shown in Figure 11, the number of first fiber layers L1 included in the middle and inner layers of the fiber-reinforced resin layer 20 is equal to the number of first fiber layers L1 included in the outer layers of the fiber-reinforced resin layer 20. "Middle of the fiber-reinforced resin layer 20" means the middle position in the lamination direction of the fiber-reinforced resin layer 20. If the fiber-reinforced resin layer 20 has an odd number of fiber layers, "middle of the fiber-reinforced resin layer 20" includes the intermediate fiber layer based on the number of layers of the fiber-reinforced resin layer 20, and if the fiber-reinforced resin layer 20 has an even number of fiber layers, it means the boundary between two fiber layers located in the middle based on the number of layers of the fiber-reinforced resin layer 20. In the example in Figure 12, the middle of the fiber-reinforced resin layer 20 is the 6th layer. If the fiber-reinforced resin layer 20 has, for example, 12 fiber layers, the intermediate layer is the boundary between the 6th and 7th layers.

[0050] In contrast, the number of first fiber layers L1 in the intermediate layer and the inner layer of the fiber-reinforced resin layer 20 may be greater than the number of first fiber layers L1 in the outer layer. With this configuration of the gas tank 100, by arranging more first fiber layers L1 in the inner layer, which is less permeable to resin material than the outer layer, the resin material can be more reliably impregnated to the innermost layer.

[0051] (C3) Figure 13 is an explanatory diagram showing another form of the first reinforcing portion 210. Figure 14 is a cross-sectional view showing position XIV-XIV in Figure 13. In each of the above embodiments, the first reinforcing portion 210 was shown to be formed by weaving the fibrous material so that every two fibers are alternating. In contrast, as shown in Figures 13 and 14, the first reinforcing portion 210 may be formed by weaving the fibrous material so that every one fiber is alternating.

[0052] (C4) In the second embodiment described above, an example was shown in which the first continuous laminated section ST1 is located on the inner layer side of the second continuous laminated section ST2. In contrast, the second continuous laminated section ST2 may be located on the inner layer side of the first continuous laminated section ST1. According to this form of gas tank 100, the strength of the gas tank 100 can be improved by providing more second fiber layers L2 on the inner layer side.

[0053] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of symbols]

[0054] 10...Liner, 12...Body, 14...Dome, 16,17...Fastener, 20...Fiber-reinforced resin layer, 22A,22B...Fiber material, 42...First supply section, 44...Second supply section, 100...Gas tank, 210...First reinforcement section, 211~215,221~225...Fiber material, 220...Second reinforcement section, 300...Manufacturing equipment, AX...Central axis, BD...Boundary, BR...Boundary section, GP...Gap, L1...First fiber layer, L11,L12...Layer, L2...Second fiber layer, L21,L22...Layer, OR1,OR1b,OR2,OR2b...Transfer path, ST1...First continuous lamination section, ST2...Second continuous lamination section, TB1,TB2...Surface

Claims

1. It is a gas tank, A liner having a cylindrical body and a pair of dome-shaped portions provided at both ends of the body, The liner comprises a reinforcing layer covering the outer circumference, The aforementioned reinforcing layer is A first reinforcing portion, in which the fibers are wrapped around the outer circumference of the body portion, is provided with at least one first fiber layer, It has at least one second fiber layer provided on the outer circumference of the body, in which the fibers are wound around the central axis of the liner at a predetermined angle, The outermost layer of the reinforcing layer is the first fiber layer, The innermost layer of the reinforcing layer is the first fiber layer, The first fiber layer is provided with the first reinforcing portion on the outer circumference of the body portion, and also has the first reinforcing portion on the outer circumference of each of the dome portions. The second fiber layer has the second reinforcing portion on the outer circumference of the body portion and the first reinforcing portion on the outer circumference of each of the dome portions. Gas tank.

2. A gas tank according to claim 1, The reinforcing layer comprises an alternating laminated portion in which the first fiber layer and the second fiber layer are alternately laminated. Gas tank.

3. A gas tank according to claim 1, The aforementioned reinforcing layer is A first continuous laminated section in which multiple first fiber layers are continuously laminated, A second continuous laminated section comprising a plurality of the second fiber layers being continuously laminated, Gas tank.

4. A gas tank according to claim 3, The first continuous laminated portion is located on the inner layer side of the reinforcing layer than the second continuous laminated portion. Gas tank.

5. A gas tank according to claim 1, The number of layers of the first fiber layer included in the middle of the reinforcing layer and on the inner side of the middle is greater than the number of layers of the first fiber layer included on the outer side of the middle. Gas tank.

6. The gas tank according to claim 1, wherein the total thickness of the second fiber layer is 5 millimeters or less.

7. A gas tank according to claim 1, The number of layers in the first fiber layer is greater than the number of layers in the second fiber layer. Gas tank.

8. A gas tank according to claim 1, The first fiber layer is provided with the first reinforcing portion on the outer circumference of each of the dome portions. The second fiber layer is provided with the second reinforcing portion on the outer circumference of each of the dome portions. Gas tank.

9. A method for manufacturing a gas tank, A step of preparing a liner having a cylindrical body and a pair of dome portions provided at both ends of the body, The process includes forming a substrate having a reinforcing layer on the outer circumference of the liner, The step of forming the substrate is: A step of forming at least one first fiber layer having a first reinforcing portion around the outer circumference of the body portion, in which the fibers are wrapped so as to be woven alternately, The process includes forming at least one second fiber layer, which has a second reinforcing portion on the outer circumference of the body portion, in which the fibers are wound around the central axis of the liner at a predetermined angle, The outermost layer of the reinforcing layer is the first fiber layer, The innermost layer of the reinforcing layer is the first fiber layer, The first fiber layer is provided with the first reinforcing portion on the outer circumference of the body portion, and also has the first reinforcing portion on the outer circumference of each of the dome portions. The second fiber layer has the second reinforcing portion on the outer circumference of the body portion and the first reinforcing portion on the outer circumference of each of the dome portions. A method for manufacturing gas tanks.

10. A method for manufacturing a gas tank according to claim 9, The process involves placing the formed substrate inside the mold and closing the mold, The process further comprises filling the closed mold with a resin material to impregnate the fiber layer of the substrate with the resin material. A method for manufacturing gas tanks.

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