tank

Abstract

To provide a tank capable of reducing a usage amount of a fiber reinforcing resin while securing strength of dome parts.SOLUTION: A tank 1 includes a liner 10 having a cylindrical trunk part 11 and a pair of dome parts (a first dome part 12, and a second dome part 13) provided at both ends in an axial direction of the trunk part 11, and a reinforcing layer 20 covering the liner 10 and formed of the fiber reinforcing resin which is a fiber bundle impregnated with a resin, the reinforcing layer 20 having a first partial reinforcing layer 24 and a second partial reinforcing layer 25 arranged ranging from the peak side of the dome parts beyond boundary parts 14, 15 between the dome parts and the trunk part 11 to a part of the trunk part 11, respectively, and an outside hoop layer 26 arranged outside the first partial reinforcing layer 24 and the second partial reinforcing layer 25 and formed to press ends 241, 251.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] One example of a tank such as a hydrogen tank is described in Patent Document 1 below. The tank described in Patent Document 1 includes a liner having a cylindrical body and a pair of dome portions provided at both axial ends of the body, and a reinforcing layer provided to cover the liner. The reinforcing layer is formed by winding a resin-impregnated fiber bundle around the outer surface of the liner using a filament winding (FW) method. More specifically, the reinforcing layer is formed by a first tape arranged around the liner by helical winding and hoop winding, and a second tape arranged over an area shorter than the diameter of the body so as to pass through at least the dome portions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2019-527321 Summary of the Invention [Problem to be solved by the invention]

[0004] In a tank, the strength of the dome section (in other words, the axial strength of the tank) is ensured by helical winding, and the strength of the body section (in other words, the radial strength of the tank) is ensured by hoop winding. Helical winding is a method of winding fiber bundles in a spiral shape around the outer periphery of the dome section and the body section, so it is formed not only on the dome section but also on the body section, but its contribution to reinforcing the body section is small.

[0005] In the tank described in Patent Document 1, a continuous fiber bundle is helically wound around the dome sections at both ends of the liner, so the fiber bundle always passes through the body section. This creates a problem of wasting the amount of fiber-reinforced resin used, in which the fiber bundle is impregnated with resin. For this reason, there is a need for a tank that can reduce the amount of fiber-reinforced resin used while maintaining the strength of the dome section.

[0006] The present invention has been made to solve such technical problems, and aims to provide a tank that can reduce the amount of fiber-reinforced resin used while ensuring the strength of the dome portion. [Means for solving the problem]

[0007] The tank of the present invention is a tank comprising a liner having a cylindrical body portion and a pair of dome portions provided at both axial ends of the body portion, and a reinforcing layer covering the liner and formed from a fiber-reinforced resin in which fiber bundles are impregnated with resin, wherein the reinforcing layer comprises a partial reinforcing layer arranged from the apex side of the dome portion across the boundary between the dome portion and the body portion to a part of the body portion, and an outer hoop layer arranged outside the partial reinforcing layer and formed so as to press down on the end portion of the partial reinforcing layer on the body portion side.

[0008] According to the tank of the present invention, the partial reinforcing layer extends from the apex of the dome portion, over the boundary between the dome portion and the body portion, and into a portion of the body portion, thereby reinforcing the dome portion with the partial reinforcing layer. This reduces the amount of helical layer reinforcing the dome portion, and therefore reduces the amount of helical layer required in the body portion. As a result, the strength of the dome portion can be maintained while reducing the amount of fiber-reinforced resin used compared to conventional methods.

[0009] In the tank according to the present invention, it is preferable that the end portion of the partial reinforcing layer is inclined from the outside to the inside of the tank so that the thickness thereof becomes thinner.

[0010] This reduces the formation of steps at the ends of the partial reinforcement layer, thereby reducing the impact of these steps on the outer hoop layer. This reduces the gap between the partial reinforcement layer and the outer hoop layer located outside it, improving adhesion between the partial reinforcement layer and the outer hoop layer and preventing delamination. As a result, the outer hoop layer can stably hold down the ends of the partial reinforcement layer, ensuring reliable fixation of the partial reinforcement layer.

[0011] In the tank according to the present invention, it is preferable that the reinforcing layer further includes an inner hoop layer disposed inside the partial reinforcing layer so as to sandwich the end of the partial reinforcing layer between the outer hoop layer and the inner hoop layer. In this way, by sandwiching the end of the partial reinforcing layer between the outer hoop layer and the inner hoop layer, the end of the partial reinforcing layer can be further stabilized.

[0012] In the tank according to the present invention, the inner hoop layer is preferably a prefabricated cylindrical divided body, which makes it easy to fabricate the inner hoop layer.

[0013] In addition, in the tank according to the present invention, it is preferable that both axial ends of the body portion of the inner hoop layer are inclined ends that slope from the outside to the inside of the tank so that the thickness of each end becomes thinner, and that the ends of the partial reinforcement layer are positioned closer to the center of the body portion than the inclined ends of the inner hoop layer.

[0014] Since both axial ends of the inner hoop layer in the body portion are inclined ends, steps are less likely to form at the inclined ends, reducing the impact of the steps on the partial reinforcement layer. This reduces the gap between the inner hoop layer and the partial reinforcement layer disposed outside it, improving adhesion between the inner hoop layer and the partial reinforcement layer and preventing delamination. Furthermore, because the ends of the partial reinforcement layer are positioned closer to the center of the body portion than the inclined ends of the inner hoop layer, i.e., because the ends of the partial reinforcement layer are positioned on a relatively flat body portion, the outer hoop layer can stably press the ends of the partial reinforcement layer. [Effects of the Invention]

[0015] The present invention has an object to provide a tank that can reduce the amount of fiber-reinforced resin used while ensuring the strength of the dome portion. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a cross-sectional view showing the tank according to the first embodiment. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view showing the tank according to the first embodiment. [Figure 3] FIG. 6 is a cross-sectional view showing a tank according to a second embodiment. [Figure 4] FIG. 10 is a partially enlarged cross-sectional view showing a tank according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of a tank according to the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated explanations will be omitted. In the following description, an example will be given in which a tank is mounted on a fuel cell vehicle and filled with high-pressure hydrogen gas. However, the gas that can be filled into the tank is not limited to hydrogen gas, and may be various compressed gases such as CNG (compressed natural gas), or various liquefied gases such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas).

[0018] [First embodiment] Fig. 1 is a cross-sectional view showing a tank according to the first embodiment, and Fig. 2 is a partially enlarged cross-sectional view showing the tank according to the first embodiment. As shown in Fig. 1, the tank 1 according to this embodiment is a substantially cylindrical high-pressure gas storage container with both ends rounded like a dome, and includes a liner 10 having gas barrier properties, a reinforcing layer 20 formed so as to cover the outer peripheral surface of the liner 10, a nozzle 30 attached to one end of the tank 1, and a valve 40 for closing the nozzle 30.

[0019] The liner 10 is a hollow container having a storage space 2 for storing high-pressure hydrogen and is made of a resin material with gas barrier properties against hydrogen gas. The liner 10 is composed of a cylindrical body 11 and a pair of dome sections (a first dome section 12 and a second dome section 13) provided at both ends of the body 11 in the axial direction (i.e., the axial L direction of the tank 1). The body 11 extends a predetermined length along the axial L direction of the tank 1. The first dome section 12 is disposed, for example, on the right side of the body 11, and the second dome section 13 is disposed on the left side of the body 11. The first dome section 12 and the second dome section 13 each have a hemispherical shape so that their diameters decrease with increasing distance from the body 11. In this embodiment, the boundary between the hemispherical first dome section 12 and the cylindrical body 11 is designated as 14, and the boundary between the hemispherical second dome section 13 and the cylindrical body 11 is designated as 15.

[0020] An opening is formed at the top of one of the pair of dome sections (first dome section 12 in this embodiment), and a nozzle 30 integrally molded with liner 10 is inserted into this opening. On the other hand, no opening is formed in second dome section 13. Note that second dome section 13 may have an opening through which nozzle 30 is inserted, similar to first dome section 12.

[0021] The liner 10 having such a configuration may be formed by forming the fuselage segment, the first dome segment, and the second dome segment using a resin material such as polyethylene or nylon by injection molding or blow molding, and then connecting these segments, or may be integrally formed by rotational blow molding using a resin material such as polyethylene or nylon.

[0022] The reinforcing layer 20 has the function of reinforcing the liner 10 to improve the mechanical strength, such as the rigidity and pressure resistance, of the tank 1, and has multiple layers formed of fiber-reinforced resin. The fiber-reinforced resin is formed by impregnating a fiber bundle, for example, made of fibers having a diameter of about several μm, with a thermosetting resin or a thermoplastic resin. Examples of the fiber include reinforcing fibers such as carbon fiber, glass fiber, aramid fiber, alumina fiber, boron fiber, steel fiber, PBO fiber, natural fiber, and high-strength polyethylene fiber. In particular, it is preferable to use carbon fiber from the viewpoints of light weight and mechanical strength.

[0023] Examples of thermosetting resins include epoxy resins, modified epoxy resins such as vinyl ester resins, phenolic resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, polyurethane resins, and thermosetting polyimide resins. Examples of thermoplastic resins include polyether ether ketone, polyphenylene sulfide, polyacrylic esters, polyimides, and polyamides.

[0024] As shown in Figure 1, the reinforcing layer 20 includes an inner helical layer 21 that covers the entire liner 10, an inner hoop layer 22 that is located outside the inner helical layer 21 and corresponds to the body portion 11 of the liner 10, a first partial reinforcing layer 24 that is located outside the inner helical layer 21 and corresponds to the first dome portion 12 of the liner 10, a second partial reinforcing layer 25 that is located outside the inner helical layer 21 and corresponds to the second dome portion 13 of the liner 10, an outer hoop layer 26 that is formed to press down on an end 241 of the first partial reinforcing layer 24 and an end 251 of the second partial reinforcing layer 25, and an outer helical layer 27 that is located outside the outer hoop layer 26 and corresponds to the entire liner 10.

[0025] The inner helical layer 21 is formed by helically winding a fiber bundle impregnated with resin around the outer peripheral surfaces of the body portion 11, the first dome portion 12, and the second dome portion 13.

[0026] The inner hoop layer 22 is formed by hoop-winding a fiber bundle impregnated with a resin around the outer circumferential surface of the inner helical layer 21 at a position corresponding to the body portion 11. As shown in Figures 1 and 2, in the axial direction of the body portion 11 (i.e., the axial L direction of the tank 1), one end of the inner hoop layer 22 (e.g., the end near the first dome portion 12) is a sloped end 221 that slopes from the outside to the inside of the tank 1 so as to become thinner. The other end of the inner hoop layer 22 (e.g., the end near the second dome portion 13) is a sloped end 222 that slopes from the outside to the inside of the tank 1 so as to become thinner.

[0027] One method for forming the inclined end portions 221, 222 of the inner hoop layer 22 is to hoop-wind a resin-impregnated fiber bundle from one end to the other along the axial direction of the body 11 to form a first hoop layer, and then hoop-wind another fiber bundle from the other end to the first end to form a second hoop layer. The fiber bundle is then shifted so that the start position of the second hoop layer is closer to the center of the body 11 than the end position of the first hoop layer, and the end position of the second hoop layer is also shifted so that the start position of the first hoop layer is closer to the center of the body 11 than the start position of the first hoop layer. The third, fourth, ..., Nth hoop layers are then sequentially stacked in the same manner, with the shifted positions shifted to form the inner hoop layer 22 having the inclined end portions 221, 222.

[0028] The first partial reinforcement layer 24 is a reinforcement layer that mainly corresponds to the first dome section 12, and the second partial reinforcement layer 25 is a reinforcement layer that mainly corresponds to the second dome section 13. These two partial reinforcement layers are both dome-shaped, but differ in whether or not they have an opening through which the nozzle 30 is inserted. That is, the first partial reinforcement layer 24 has an opening through which the nozzle 30 is inserted, but the second partial reinforcement layer 25 does not have an opening. Below, an example of the first partial reinforcement layer 24 will be described, and the description of the second partial reinforcement layer 25 will be simplified.

[0029] 1 and 2, the first partial reinforcement layer 24 is disposed from the apex side of the first dome section 12, across the boundary section 14 between the first dome section 12 and the body section 11, and up to a portion of the body section 11. Here, the portion of the body section 11 is, for example, in a range of 100 mm to 200 mm from the boundary section 14. Furthermore, an end section 241 of the first partial reinforcement layer 24 on the body section 11 side is inclined from the outside to the inside of the tank 1 so as to become thinner. Furthermore, the end section 241 is disposed closer to the center of the body section 11 than the inclined end section 221 of the inner hoop layer 22.

[0030] The first partial reinforcement layer 24 is formed by, for example, laminating a plurality of resin-impregnated fiber bundles by an AFD (Automated Fiber Placement) method on portions of the outer peripheral surfaces of the inner helical layer 21 and the inner hoop layer 22. For example, the first partial reinforcement layer 24 is formed by attaching prepregs made of CFRP (Carbon Fiber Reinforced Plastics) to portions of the outer peripheral surfaces of the inner helical layer 21 and the inner hoop layer 22 using an automatic fiber placement machine.

[0031] One method for forming the inclined end 241 of the first partial reinforcement layer 24 is to form a first layer by attaching fiber bundles impregnated with resin, and then form a second layer on top of that by shifting the fiber bundles so that the end position of the second layer is closer to the apex of the first dome section 12 than the end position of the first layer. Thereafter, by laminating the third, fourth, ..., Nth layers in the same manner while shifting the fiber bundles in sequence, the first partial reinforcement layer 24 having the inclined end 241 can be formed.

[0032] The first partial reinforcement layer 24 may be formed using a mandrel having the same outer diameter as the inner helical layer 21 and the inner hoop layer 22. In this case, the first partial reinforcement layer 24 formed on the mandrel may be removed from the mandrel after curing and then fitted into the inner helical layer 21 and the inner hoop layer 22, or may be removed from the mandrel in an uncured state and then fitted into the inner helical layer 21 and the inner hoop layer 22.

[0033] However, because gaps are less likely to occur due to the pressing of rollers attached to the automatic fiber placement machine, it is preferable to form the first partial reinforcement layer 24 by directly laminating fiber bundles on the outer peripheral surfaces of the inner helical layer 21 and the inner hoop layer 22. Suppressing the occurrence of gaps in this way improves adhesion between the first partial reinforcement layer 24 and the inner helical layer 21 and the inner hoop layer 22, and prevents delamination. Note that the width of the resin-impregnated fiber bundles used in the AFD method may be different from the width of the resin-impregnated fiber bundles used in the FW method.

[0034] 1, the second partial reinforcement layer 25 is disposed from the apex side of the second dome section 13, across the boundary 15 between the second dome section 13 and the body section 11, and up to a part of the body section 11. An end 251 of the second partial reinforcement layer 25 on the body section 11 side is inclined from the outside to the inside of the tank 1 so as to become thinner. The end 251 is disposed closer to the center of the body section 11 than the inclined end 222 of the inner hoop layer 22.

[0035] The outer hoop layer 26 is disposed on the outside of the first partial reinforcing layer 24 and the second partial reinforcing layer 25, and is formed so as to press against an end 241 of the first partial reinforcing layer 24 and an end 251 of the second partial reinforcing layer 25. Specifically, as shown in FIG. 1 , the outer hoop layer 26 is disposed at a position corresponding to the body portion 11 of the liner 10 while pressing against the end 241 of the first partial reinforcing layer 24 and the end 251 of the second partial reinforcing layer 25. The outer hoop layer 26 is formed over the entire length of the body portion 11, and has a first portion 261 covering a portion of the first partial reinforcing layer 24 including the end 241, a second portion 262 covering a portion of the second partial reinforcing layer 25 including the end 251, and a third portion 263 covering the inner hoop layer 22 between the first partial reinforcing layer 24 and the second partial reinforcing layer 25.

[0036] The end of the first portion 261 is tapered from the outside to the inside of the tank 1 so as to reduce its thickness. Similarly, the end of the second portion 262 is tapered from the outside to the inside of the tank 1 so as to reduce its thickness. This makes it difficult for steps to be formed at these end portions, which reduces the effect of steps on the outer helical layer 27 when forming the outer helical layer 27 outside the outer hoop layer 26, and prevents delamination.

[0037] The outer hoop layer 26 is formed by hoop-winding a fiber bundle impregnated with resin around the outer peripheral surfaces of the first partial reinforcement layer 24, the second partial reinforcement layer 25 and the inner hoop layer 22 between them, for example, so as to press down on the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25, respectively.

[0038] The outer helical layer 27 is the outermost layer of the reinforcing layer 20, and is formed so as to cover the first partial reinforcing layer 24, the second partial reinforcing layer 25, and the outer hoop layer 26. This outer helical layer 27 is formed, for example, by helically winding a fiber bundle impregnated with resin around the outer peripheral surfaces of the first partial reinforcing layer 24, the second partial reinforcing layer 25, and the outer hoop layer 26.

[0039] On the other hand, the nozzle 30 is made of a metal material such as stainless steel or aluminum alloy, which has been processed into a predetermined shape. The nozzle 30 has a substantially cylindrical nozzle body 31 that extends along the axis L of the tank 1, and a flange 32 that is formed integrally with the nozzle body 31 and protrudes in the radial direction of the tank 1. A communication hole 33 that communicates with the storage space 2 of the tank 1 is provided inside the nozzle body 31. A female thread portion for threading onto the valve 40 is formed on the inner peripheral wall of the nozzle body 31 (i.e., the portion that forms the communication hole 33).

[0040] The valve 40 is a member for filling and discharging hydrogen gas into the storage space 2 of the tank 1, and is made of a metal material such as stainless steel or an aluminum alloy. The valve 40 is inserted into the communication hole 33 so as to close the nozzle 30, and the male thread portion formed on the outer peripheral wall of the valve 40 is screwed onto the nozzle 30.

[0041] The tank 1 according to this embodiment includes a first partial reinforcement layer 24 extending from the apex of the first dome section 12, across the boundary 14 between the first dome section 12 and the body section 11, to a portion of the body section 11, and a second partial reinforcement layer 25 extending from the apex of the second dome section 13, across the boundary 15 between the second dome section 13 and the body section 11, to a portion of the body section 11. Therefore, the first dome section 12 can be reinforced by the first partial reinforcement layer 24, and the second dome section 13 can be reinforced by the second partial reinforcement layer 25. This reduces the amount of helical layer reinforcing the dome section, and therefore reduces the amount of helical layer formed in the body section as the helical layer is formed. As a result, the strength of the first dome section 12 and the second dome section 13 can be maintained while reducing the amount of fiber-reinforced resin used compared to conventional methods.

[0042] Furthermore, the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25 are inclined from the outside to the inside of the tank 1 so that their thicknesses become thinner, reducing the likelihood of formation of a step at these end portions. This reduces the impact of the step on the outer hoop layer 26. Therefore, meandering of the fiber bundles can be prevented when forming the outer hoop layer 26 outside the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25. This reduces gaps between the first partial reinforcement layer 24 and the second partial reinforcement layer 25 and the outer hoop layer 26 disposed thereoutside, improving adhesion with the outer hoop layer 26 and preventing delamination. As a result, the outer hoop layer 26 can stably hold the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25, respectively, and reliably fix the first partial reinforcement layer 24 and the second partial reinforcement layer 25 to the outer hoop layer 26.

[0043] The reinforcement layer 20 further includes an inner hoop layer 22 disposed inside the first partial reinforcement layer 24 and the second partial reinforcement layer 25 so as to sandwich the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25 between the outer hoop layer 26 and the inner hoop layer 22. By sandwiching the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25 between the outer hoop layer 26 and the inner hoop layer 22 in this manner, the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25 can be reliably stabilized.

[0044] Furthermore, because both ends of the inner hoop layer 22 are inclined ends 221, 222, steps are less likely to be formed at these inclined ends 221, 222, reducing the impact of the steps on the first partial reinforcement layer 24 and the second partial reinforcement layer 25. This makes it possible to reduce gaps between the inner hoop layer 22 and the first partial reinforcement layer 24 and the second partial reinforcement layer 25 arranged thereoutside, thereby improving adhesion between the inner hoop layer 22 and the first partial reinforcement layer 24 and the second partial reinforcement layer 25, and preventing delamination.

[0045] Furthermore, the end 241 of the first partial reinforcement layer 24 is positioned closer to the center of the body portion 11 than the inclined end 221 of the inner hoop layer 22, and the end 251 of the second partial reinforcement layer 25 is positioned closer to the center of the body portion 11 than the inclined end 222 of the inner hoop layer 22. In this way, the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25 can be positioned on the relatively flat body portion 11, so that the outer hoop layer 26 can stably press these end portions 241, 251.

[0046] [Second embodiment] A second embodiment of the tank will be described below with reference to Figures 3 and 4. The tank 1A of this embodiment differs from the first embodiment described above in that it does not include the inner helical layer 21 and includes an inner hoop layer 23 made of a prefabricated divided body instead of the inner hoop layer 22. Only these differences will be described below.

[0047] Specifically, the reinforcing layer 20A has an inner hoop layer 23 that covers the body portion 11 of the liner 10, a first partial reinforcing layer 24 that is arranged outside the inner hoop layer 23 and covers the first dome portion 12 and a portion of the inner hoop layer 23, a second partial reinforcing layer 25 that is arranged outside the inner hoop layer 23 and covers the second dome portion 13 and a portion of the inner hoop layer 23, an outer hoop layer 26 that is formed to press against an end 241 of the first partial reinforcing layer 24 and an end 251 of the second partial reinforcing layer 25, and an outer helical layer 27 that is arranged outside the outer hoop layer 26 and formed to cover the entire liner 10.

[0048] The inner hoop layer 23 is formed so as to directly cover the outer peripheral surface of the body 11. This inner hoop layer 23 is composed of a prefabricated cylindrical divided body and is fitted into the body 11 of the liner 10. In the axial direction of the body 11 (i.e., the axial L direction of the tank 1), one end of the inner hoop layer 23 (for example, the end near the first dome section 12) is a sloped end 231 that slopes from the outside to the inside of the tank 1 so as to become thinner. The other end of the inner hoop layer 23 (for example, the end near the second dome section 13) is a sloped end 232 that slopes from the outside to the inside of the tank 1 so as to become thinner.

[0049] The inner hoop layer 23 is formed by winding a plurality of resin-impregnated fiber bundles around the outer circumferential surface of a cylindrical mandrel in a hoop winding manner, curing the bundles, and then removing the bundles from the mandrel. The mandrel is made of metal, for example, and has the same outer diameter as the body portion 11 of the liner 10.

[0050] The inclined end portions 231, 232 of the inner hoop layer 23 can be formed, for example, by hoop-winding a resin-impregnated fiber bundle from one end to the other along the axial direction of the mandrel to form a first hoop layer, and then hoop-winding another fiber bundle from the other end of the mandrel to form a second hoop layer. The fiber bundle is then shifted so that the start position of the second hoop layer is closer to the center of the mandrel than the end position of the first hoop layer, and the end position of the second hoop layer is also shifted so that the start position of the second hoop layer is closer to the center of the mandrel than the start position of the first hoop layer. The same method is then used to sequentially shift and stack the third, fourth, ..., Nth hoop layers, forming the inner hoop layer 23 with the inclined end portions 231, 232.

[0051] The inner hoop layer 23 thus produced is fitted into the body portion 11 of the liner 10 with the liner 10 inserted therethrough. To prevent misalignment, it is preferable to fill an adhesive or the like between the body portion 11 and the inner hoop layer 23.

[0052] In this embodiment, the first partial reinforcement layer 24 is formed to directly cover the first dome portion 12 of the liner 10, and the second partial reinforcement layer 25 is formed to directly cover the second dome portion 13 of the liner 10. An end portion 241 of the first partial reinforcement layer 24 and an end portion 251 of the second partial reinforcement layer 25 are sandwiched between the outer hoop layer 26 and the inner hoop layer 23.

[0053] According to the tank 1A of this embodiment, in addition to obtaining the same effects as those of the first embodiment described above, since the inner hoop layer 23 is made of a prefabricated cylindrical divided body, the inner hoop layer 23 can be easily produced compared to when the inner hoop layer is formed by directly winding a fiber bundle around the body portion 11.

[0054] Furthermore, because both ends of the inner hoop layer 23 are inclined ends 231, 232, steps are less likely to be formed at these inclined ends 231, 232, reducing the impact of the steps on the first partial reinforcement layer 24 and the second partial reinforcement layer 25. This makes it possible to reduce gaps between the inner hoop layer 23 and the first partial reinforcement layer 24 and second partial reinforcement layer 25 arranged thereoutside, thereby improving adhesion between the inner hoop layer 23 and the first partial reinforcement layer 24 and second partial reinforcement layer 25, and preventing delamination.

[0055] Furthermore, the end 241 of the first partial reinforcement layer 24 is positioned closer to the center of the body portion 11 than the inclined end 231 of the inner hoop layer 23, and the end 251 of the second partial reinforcement layer 25 is positioned closer to the center of the body portion 11 than the inclined end 232 of the inner hoop layer 23. By positioning the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25 on the relatively flat body portion 11 in this manner, it is possible to stably press these end portions 241, 251 by the outer hoop layer 26.

[0056] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as set forth in the claims.

[0057] For example, in the above-described embodiment, an example was given in which the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25 are sandwiched between the outer hoop layer 26 and the inner hoop layer 22 or the inner hoop layer 23, i.e., an example in which the end portions of these partial reinforcement layers are sandwiched between two hoop layers, but the present invention is not limited to this. For example, a hoop layer may be disposed on the outside of the end 241 of the first partial reinforcement layer 24 and the end 251 of the second partial reinforcement layer 25, and a helical layer may be disposed on the inside. [Explanation of symbols]

[0058] 1, 1A: tank, 2: storage space, 10: liner, 11: body portion, 12: first dome portion, 13: second dome portion, 14, 15: boundary portion, 20, 20A: reinforcing layer, 21: inner helical layer, 22, 23: inner hoop layer, 24: first partial reinforcing layer, 25: second partial reinforcing layer, 26: outer hoop layer, 27: outer helical layer, 30: nozzle, 31: nozzle body portion, 32: flange portion, 33: communication hole, 40: valve, 221, 222, 231, 232: inclined end portion, 241, 251: end portion, 261: first portion, 262: second portion, 263: third portion

Claims

1. A tank comprising: a liner having a cylindrical body portion and a pair of dome portions provided at both ends of the body portion in the axial direction; and a reinforcing layer covering the liner and formed of a fiber reinforced resin in which fiber bundles are impregnated with resin, The reinforcing layer is a partial reinforcing layer disposed from the apex side of the dome portion across the boundary between the dome portion and the body portion to a part of the body portion; an outer hoop layer disposed outside the partial reinforcing layer and formed to press an end portion of the partial reinforcing layer on the body portion side; an inner hoop layer disposed inside the partial reinforcing layer so as to sandwich the end portion of the partial reinforcing layer between the outer hoop layer and the inner hoop layer; and the end portion of the partial reinforcing layer is inclined from the outside to the inside of the tank so that the thickness thereof becomes thinner; the inner hoop layer has inclined ends at both ends of the body portion in the axial direction, the inclined ends being inclined from the outside toward the inside of the tank so that the thickness of each end becomes thinner; The tank is characterized in that the end portion of the partial reinforcing layer is positioned closer to the center of the body portion than the inclined end portion of the inner hoop layer so as to be positioned on the flat body portion.

2. 10. The tank of claim 1, wherein the inner hoop layer is a prefabricated cylindrical segment.

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