tank

Abstract

To provide a tank capable of securing sealability in a simple construction.SOLUTION: A tank 1 includes a resin liner 10 in which a storage space 2 is provided, a metal mouthpiece 30 having a communication hole 33 communicating with the storage space 2 and molded integrally with the liner 10, a metal cylinder body 50 inserted into the lower end of the communication hole 33 and arranged coaxially with the communication hole 33, and a valve 40 inserted into the communication hole 33 so as to close the mouthpiece 30, and having a lower end 41 further inserted into the metal cylinder body 50, the liner 10 having a wraparound part 123 wrapping around from the bottom of the mouthpiece 30 into the communication hole 33 to come into contact with the outer peripheral face of the metal cylinder body 50. Between the inner peripheral face of the wraparound part 123 and the outer peripheral face of the metal cylinder body 50, a first O-ring 60 is arranged in the peripheral direction. Between the inner peripheral face of the metal cylinder body 50 and the outer peripheral face of the lower end 41 of the valve 40, a second O-ring 62 is arranged in the peripheral direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a tank, and more particularly to a seal structure for a tank. [Background technology]

[0002] An example of a conventional tank in this technical field is described in Patent Document 1. The tank described in Patent Document 1 includes a resin liner having a storage space for storing gas therein and an opening communicating with the storage space, a reinforcing layer formed on the outer peripheral surface of the liner, a nozzle attached to the opening of the liner, and a valve inserted into the nozzle. A tank having such a structure employs a sealing structure in which an O-ring is disposed between the nozzle and the liner to prevent leakage of the stored gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-116926 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the tank described above requires the provision of a circumferential groove in the nozzle for fitting an O-ring, which results in a complicated nozzle structure. Furthermore, recently, attention has been focused on integrally molding a resin liner and nozzle to improve workability and prevent epoxy resin from penetrating between the nozzle and the liner during the formation of the reinforcing layer. However, when the liner and nozzle are integrally molded, providing a circumferential groove in the nozzle for fitting an O-ring further complicates the nozzle structure.

[0005] The present invention has been made to solve such technical problems, and has an object to provide a tank that can ensure sealing performance with a simple structure. [Means for solving the problem]

[0006] The tank of the present invention is a cylindrical tank having a storage space for storing gas, and when the outside of the tank is positioned at the top along the axial direction of the tank and the interior side of the tank is positioned at the bottom, the tank comprises: a resin liner in which the storage space is provided; a metal nozzle having a communication hole communicating with the storage space and integrally molded with the liner; a metal cylinder inserted into the lower end of the communication hole of the nozzle and arranged coaxially with the communication hole; and a valve inserted into the communication hole to close the nozzle, the lower end of which is further inserted into the metal cylinder, wherein the liner has a wraparound portion that wraps around from the bottom of the nozzle into the inside of the communication hole and contacts the outer peripheral surface of the metal cylinder, and a first O-ring is arranged circumferentially between the inner peripheral surface of the wraparound portion and the outer peripheral surface of the metal cylinder, and a second O-ring is arranged circumferentially between the inner peripheral surface of the metal cylinder and the outer peripheral surface of the lower end of the valve.

[0007] In the tank according to the present invention, a metal cylindrical body is inserted into the lower end of the connecting hole of the nozzle, which is formed integrally with the liner and nozzle, and a first O-ring is circumferentially disposed between the outer circumferential surface of the metal cylindrical body and the inner circumferential surface of the wrap-around portion of the liner to ensure a seal between the metal cylindrical body and the liner, and a second O-ring is circumferentially disposed between the inner circumferential surface of the metal cylindrical body and the outer circumferential surface of the lower end of the valve inserted into the metal cylindrical body to ensure a seal between the metal cylindrical body and the valve. By using a metal cylindrical body in this way to achieve a seal between the metal cylindrical body and the liner and between the metal cylindrical body and the valve, there is no longer a need to provide a circumferential groove in the nozzle for fitting an O-ring, as in the conventional case, and therefore the sealability of the tank can be ensured with a simple structure.

[0008] In the tank according to the present invention, it is preferable that the first O-ring and the second O-ring are positioned at the same height in the axial direction of the tank. In this way, by aligning the pressing forces of the first O-ring and the second O-ring at the same height, the pressing forces can be strengthened, thereby improving the sealing performance between the metallic cylindrical body and the liner and between the metallic cylindrical body and the valve.

[0009] In the tank according to the present invention, the metal cylindrical body is preferably fixed to the lower end of the communication hole of the nozzle by screwing. This allows the metal cylindrical body to be inserted and fixed into the lower end of the communication hole of the nozzle more easily and reliably than by methods such as press-fitting. Furthermore, since the metal cylindrical body is detachably fixed to the lower end of the communication hole, the metal cylindrical body can be removed and replaced if insertion into the communication hole fails. [Effects of the Invention]

[0010] According to the present invention, the sealing performance of the tank can be ensured with a simple structure. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a cross-sectional view showing the tank according to the embodiment. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing part A in FIG. [Figure 3] FIG. 3 is an enlarged cross-sectional view showing part B of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of a tank according to the present invention will be described with reference to the drawings. In the following description, an example will be given in which the 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).

[0013] Fig. 1 is a cross-sectional view showing a tank according to an embodiment, Fig. 2 is an enlarged cross-sectional view showing part A in Fig. 1, and Fig. 3 is an enlarged cross-sectional view showing part B in Fig. 2. As shown in Fig. 1, the tank 1 according to this embodiment is a high-pressure gas storage container having a substantially cylindrical shape 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.

[0014] 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 on both the left and right sides 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 and the second dome section 13 are formed continuously on both the left and right sides of the body 11, and are hemispherical in shape so that their diameters decrease as they move away from the body 11.

[0015] An opening is formed at the top of one of the pair of dome sections (in this embodiment, the first dome section 12), and a nozzle 30 integrally molded with the liner 10 is inserted into this opening. On the other hand, no opening is formed in the second dome section 13. Note that the second dome section 13 may have an opening into which the nozzle 30 is inserted, similar to the first dome section 12.

[0016] The liner 10 having the above structure is formed by forming a fuselage section, a first dome section, and a second dome section using a resin material such as polyethylene or nylon by injection molding, blow molding, or the like, and then connecting these sections.

[0017] 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 is formed by winding a fiber-reinforced resin around the outer peripheral surface of the liner 10 multiple times using a filament winding (FW) method. The fiber-reinforced resin is formed by impregnating a fiber bundle, which is made by bundling fibers having a diameter of, for example, about several μm, with a thermosetting 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, and carbon fiber is particularly preferred from the viewpoints of light weight and mechanical strength.

[0018] Examples of the thermosetting resin include epoxy resin, modified epoxy resin typified by vinyl ester resin, phenol resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polyurethane resin, and thermosetting polyimide resin. Note that a thermoplastic resin may also be used as the resin impregnated into the fiber bundle.

[0019] The nozzle 30 is made of a metal material such as stainless steel or aluminum alloy and processed into a predetermined shape. The nozzle 30 has a cylindrical nozzle body 31 extending along the axis L of the tank 1, and a flange 32 connected to the nozzle body 31 and projecting radially from the tank 1. A communication hole 33 communicating with the storage space 2 of the tank 1 is provided inside the nozzle body 31. The communication hole 33 has a generally cylindrical shape. A first female thread 34 for threading with the valve 40 and a second female thread 35 for threading with a metal cylindrical body 50 (described later) are formed on the inner peripheral wall of the nozzle body 31 (i.e., the portion forming the communication hole 33).

[0020] Next, the first dome portion 12 of the liner 10, the nozzle 30, and the valve 40 will be described in detail with reference to Figures 2 and 3. In the following description, as shown in Figure 2, the outside of the tank 1 along the axis L of the tank 1 will be referred to as the top, and the inside of the tank 1 will be referred to as the bottom.

[0021] In this embodiment, in order to increase the strength of connection between the nozzle 30 and the liner 10, which are integrally molded (more specifically, insert molded), the top of the first dome section 12 is formed to follow the shape of the flange 32 of the nozzle 30. Specifically, the top of the first dome section 12 has an upper pressing section 121 that extends above the flange 32 to encase it and press down on the flange 32 from above, a lower-side support section 122 that extends from the side wall of the flange 32 to the bottom (i.e., the bottom of the nozzle 30) and supports the flange 32 from the sides and below, and a wraparound section 123 that is connected to the lower-side support section 122 and wraps around from the bottom of the nozzle 30 into the inside of the communication hole 33 of the nozzle 30.

[0022] As shown in Figures 2 and 3, the wraparound portion 123 of the liner 10 is not formed over the entire length of the communicating hole 33 in the axial L direction of the tank 1, but extends to the lower end of the second female thread portion 35 so as not to interfere with the threaded engagement between the second female thread portion 35 of the nozzle 30 and the male thread portion 51 (described later) of the metal cylindrical body 50.

[0023] Furthermore, the thickness of the wraparound portion 123 in the radial direction of the tank 1 is preferably 0.5 mm to 3 mm, and more preferably 1 mm to 2 mm. This is the result of considering both the connection strength between the liner 10 and the nozzle 30 and the mechanical strength of the metal cylindrical body 50, while ensuring the fastening force between the nozzle 30 and the valve 40. That is, if the wraparound portion 123 of the liner 10 is made thicker, assuming that the outer diameter of the valve 40 is not changed, the connection strength between the liner 10 and the nozzle 30 can be increased, but the metal cylindrical body 50 becomes thinner accordingly, thereby reducing the mechanical strength of the metal cylindrical body 50. On the other hand, if the metal cylindrical body 50 is made thicker, the wraparound portion 123 becomes thinner, which affects the connection strength between the liner 10 and the nozzle 30. When considering both the connection strength between the liner 10 and the nozzle 30 and the mechanical strength of the metal cylindrical body 50, it is preferable that the thickness of the wraparound portion 123 be in the above-mentioned range.

[0024] The nozzle 30 having such a structure is tightly connected to the first dome portion 12 of the liner 10 without any gaps, for example by insert molding, with the axis of the communicating hole 33 aligned coaxially with the axis L of the tank 1.

[0025] A cylindrical metal tube 50 is inserted into the lower end of the communication hole 33 of the base 30. As shown in Fig. 3, a male thread portion 51 for threadably engaging with the second female thread portion 35 of the base 30 is formed on the outer peripheral wall of the upper end of the metal tube 50. The metal tube 50 is arranged coaxially with the communication hole 33, and is fixed to the lower end of the communication hole 33 of the base 30 by threadably engaging the male thread portion 51 with the second female thread portion 35 of the base 30.

[0026] The length of the metal cylindrical body 50 in the axial L direction of the tank 1 is preferably formed so that it protrudes at least 5 mm from the bottom surface of the liner 10 (more specifically, the bottom surface of the lower lateral support portion 122) when fixed to the lower end of the communication hole 33 of the nozzle 30. This makes it easy to screw the male thread portion 51 of the metal cylindrical body 50 into the second female thread portion 35 of the nozzle 30.

[0027] 2 and 3, when fixed to the lower end of the communication hole 33, the metal cylindrical body 50 comes into contact with the inner circumferential surface of the wraparound portion 123 of the first dome section 12. A first O-ring 60 is disposed between the outer circumferential surface of the metal cylindrical body 50 and the inner circumferential surface of the wraparound portion 123 in the circumferential direction.

[0028] Specifically, an outer circumferential groove 52 is provided on the outer circumferential wall of the metal cylindrical body 50. A first O-ring 60 that seals between the liner 10 and the metal cylindrical body 50 is fitted into the outer circumferential groove 52. Furthermore, a first backup ring 61 that is disposed on the outer side of the tank 1 relative to the first O-ring 60 is fitted into the outer circumferential groove 52. The first O-ring 60 and the first backup ring 61 are disposed in the outer circumferential groove 52 in a tight contact state.

[0029] The first O-ring 60 is an annular elastic member having a substantially circular cross-sectional shape, and is used to improve the sealing performance (in other words, airtightness) between the liner 10 and the metal cylindrical body 50. When the metal cylindrical body 50 is inserted into the lower end of the communication hole 33 of the nozzle 30, the first O-ring 60 is pressed against the inner circumferential surface of the wrap-around portion 123 of the adjacent liner 10, thereby sealing between the inner circumferential surface of the wrap-around portion 123 and the outer circumferential surface of the metal cylindrical body 50. The first O-ring 60 is formed of a resin such as polytetrafluoroethylene (PTFE), for example.

[0030] The first backup ring 61 is an annular member having a trapezoidal cross section. The first backup ring 61 is disposed in the outer circumferential groove 52 above the first O-ring 60 in the axial L direction (i.e., outside the tank 1) and prevents the first O-ring 60 from moving upward. The first backup ring 61 is formed from a hard resin material such as a fluorine-based resin material or nylon 46, which has a smaller coefficient of friction than the first O-ring 60 and is less susceptible to elastic deformation.

[0031] In this embodiment, it is preferable that the metal material used for the metal cylindrical body 50 is different from the metal material used for the base 30. For example, stainless steel (e.g., SUS316L) is used for the metal cylindrical body 50, and an aluminum alloy is used for the base 30. In this way, the strength of the metal cylindrical body 50 can be ensured.

[0032] On the other hand, the valve 40 is a member for filling and discharging hydrogen gas into the storage space 2, and is made of a metal material such as stainless steel or an aluminum alloy. As shown in Fig. 2, the valve 40 is inserted into the communication hole 33 so as to close the mouthpiece 30, and its lower end 41 is further inserted into the metal cylindrical body 50.

[0033] The valve 40 has a lower end portion 41 that can be inserted into part of the communication hole 33 of the base 30 and part of the metal cylindrical body 50, a top plate portion 43 that can abut against the upper end of the base 30, and a main body portion 42 that is disposed between the lower end portion 41 and the top plate portion 43 and can be inserted into the communication hole 33 of the base 30. A male thread portion 44 is provided on part of the outer circumferential surface of the main body portion 42 to threadably engage with the first female thread portion 34 formed on the inner circumferential wall of the base main body portion 31.

[0034] Furthermore, a second O-ring 62 is disposed in the circumferential direction between the outer peripheral surface of the lower end 41 of the valve 40 and the inner peripheral surface of the metal cylindrical body 50. Specifically, an outer peripheral groove 45 is provided on the outer peripheral wall of the lower end 41 of the valve 40. The second O-ring 62, which seals between the valve 40 and the metal cylindrical body 50, is fitted into the outer peripheral groove 45. Furthermore, a second backup ring 63, which is disposed on the outer side of the tank 1 relative to the second O-ring 62, is fitted into the outer peripheral groove 45. The second O-ring 62 and the second backup ring 63 are disposed in the outer peripheral groove 52 in close contact with each other.

[0035] The second O-ring 62 is an annular elastic member having a substantially circular cross-sectional shape, and is used to improve the sealing performance (in other words, airtightness) between the valve 40 and the metal cylindrical body 50. When the valve 40 is inserted into the communication hole 33 of the mouthpiece 30 and the metal cylindrical body 50, the second O-ring 62 is pressed against the inner circumferential surface of the metal cylindrical body 50, thereby sealing between the inner circumferential surface of the metal cylindrical body 50 and the outer circumferential surface of the lower end portion 41 of the valve 40. The second O-ring 62 is formed from a resin such as polytetrafluoroethylene (PTFE), for example.

[0036] The second backup ring 63 is an annular member having a trapezoidal cross section. The second backup ring 63 is disposed in the outer circumferential groove 45 above the second O-ring 62 in the axial L direction (i.e., outside the tank 1) and prevents the second O-ring 62 from moving upward. The second backup ring 63 is formed of, for example, a fluorine-based resin material or a hard resin material such as nylon 46, which has a smaller coefficient of friction than the second O-ring 62 and is less susceptible to elastic deformation.

[0037] The first O-ring 60 and the second O-ring 62 are positioned at the same height in the axial L direction of the tank 1. Furthermore, the first backup ring 61 and the second backup ring 63 are also positioned at the same height in the axial L direction of the tank 1.

[0038] In the tank 1 of this embodiment, the liner 10 and nozzle 30 are integrally molded, and a metal cylindrical body 50 is used that is inserted into the lower end of the communication hole 33 of the nozzle 30. A first O-ring 60 is disposed between the outer peripheral surface of the metal cylindrical body 50 and the inner peripheral surface of the wraparound portion 123 of the liner 10 to ensure sealing between the metal cylindrical body 50 and the liner 10, and a second O-ring 62 is disposed between the inner peripheral surface of the metal cylindrical body 50 and the outer peripheral surface of the lower end 41 of the valve 40 inserted into the metal cylindrical body 50 to ensure sealing between the metal cylindrical body 50 and the valve 40. By using the metal cylindrical body 50 in this way to achieve sealing between the metal cylindrical body 50 and the liner 10 and sealing between the metal cylindrical body 50 and the valve 40, there is no need to provide a circumferential groove in a conventional nozzle for fitting an O-ring, and therefore the sealing of the tank 1 can be ensured with a simple structure.

[0039] Furthermore, because the liner 10 and the nozzle 30 are integrally molded, there is no need to assemble the liner 10 and nozzle 30, which are manufactured separately, improving the workability of manufacturing the tank 1 and preventing the epoxy resin from penetrating between the nozzle and the liner when forming the reinforcing layer 20. Furthermore, by providing the metal cylindrical body 50 with an outer circumferential groove 52 for fitting the first O-ring 60, a compression allowance for the first O-ring 60 can be easily secured, which has the effect of improving the stability of the seal.

[0040] Furthermore, the first O-ring 60 and the second O-ring 62 are positioned at the same height in the axial L direction of the tank 1. In this way, by aligning the pressing forces of the first O-ring 60 and the second O-ring 62 to the same height, the pressing forces can be strengthened, and the sealing performance between the metal cylindrical body 50 and the liner 10, and the sealing performance between the metal cylindrical body 50 and the valve 40 can be improved.

[0041] Furthermore, since the metal cylindrical body 50 is fixed to the lower end of the communicating hole 33 of the nozzle 30 by screwing, the metal cylindrical body 50 can be inserted and fixed into the lower end of the communicating hole 33 more easily and reliably than by methods such as press-fitting. In addition, since the metal cylindrical body 50 is thereby detachably fixed to the lower end of the communicating hole 33, if insertion into the communicating hole 33 fails, the metal cylindrical body 50 can be removed and replaced.

[0042] 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. [Explanation of symbols]

[0043] 1: Tank, 10: Liner, 11: Body portion, 12: First dome portion, 13: Second dome portion, 20: Reinforcing layer, 30: Cap, 31: Cap main body portion, 32: Flange portion, 33: Communication hole, 34: First female screw portion, 35: Second female screw portion, 40: Valve, 41: Lower end portion, 42: Main body portion, 43: Top plate portion, 44: Male screw portion, 45: Peripheral groove, 50: Metal cylinder, 51: Male screw portion, 52: Peripheral groove, 121: Upper pressing portion, 122: Side lower support portion, 123: Wrap-around portion

Claims

1. A cylindrical tank having a storage space for storing gas, When the outside of the tank is defined as the top and the inside of the tank is defined as the bottom along the axial direction of the tank, a resin liner provided with the storage space; a metal mouthpiece integrally molded with the liner, the mouthpiece having a communication hole communicating with the storage space; a metal cylindrical body that is inserted into a lower end of the communication hole of the base and is arranged coaxially with the communication hole; a valve that is inserted into the communication hole so as to close the mouthpiece, and whose lower end is further inserted into the metal cylindrical body; Equipped with the liner has a wraparound portion that wraps around from the bottom of the mouthpiece into the inside of the communication hole and contacts the outer circumferential surface of the metal cylindrical body, a first O-ring is disposed in a circumferential direction between an inner circumferential surface of the wraparound portion and an outer circumferential surface of the metal cylindrical body; a second O-ring is disposed in the circumferential direction between the inner circumferential surface of the metal cylindrical body and the outer circumferential surface of the lower end of the valve; A tank, characterized in that the first O-ring and the second O-ring are positioned at the same height in the axial direction of the tank.

2. The tank according to claim 1, wherein the metal cylindrical body is fixed to the lower end of the communication hole of the nozzle by screwing.

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