Boss for hydrogen tank

Abstract

The present disclosure provides a boss for a hydrogen tank. The boss can include a nozzle boss and a fastener. The nozzle boss can include a neck extending a predetermined length and a flange disposed at a bottom portion of the neck. A cavity can be formed within the neck. The flange can be integrally formed with the neck and configured to be joined to a liner of the hydrogen tank. The fastener can be installed at a lower region of the flange and in contact with a joint between the nozzle boss and the liner to prevent fluid from leaking through the joint.

Description

[0001] Cross-citation of related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2024-0177778, filed with the Korean Intellectual Property Office on December 3, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to fuel cell vehicles, and more specifically, to hydrogen tanks in fuel cell systems. Background Technology

[0004] Natural gas vehicles or hydrogen fuel cell vehicles are equipped with pressure vessels for storing high-pressure compressed gaseous fuel.

[0005] Pressure vessels may include: a bushing made of plastic to reduce weight; a thermosetting fiber composite material configured as an outer layer surrounding the bushing; and a metal boss (joint).

[0006] Lightweight materials that can reduce the overall weight of the bushing can include plastic materials, such as polyolefin-based resins and polyamide-based resins. Composite layers can be manufactured by mixing carbon fiber or glass fiber with polymer resins (such as epoxy resin) to maintain strength, and the composite layers can be bonded together to surround the surface of the bushing. Bosses can be nozzle-shaped and made of metal to securely attach to regulators or valves (hereinafter collectively referred to as "valves") made of metal.

[0007] Such a pressure vessel may have an inlet and / or outlet through which gaseous fuel, such as hydrogen, can be introduced or discharged, and a metal boss can be inserted into the inlet. However, problems may arise in the connection between the plastic bushing and the metal boss due to the different materials used to manufacture these two components. Furthermore, material fatigue may accumulate after repeated refueling of the vehicle, increasing the risk of stored gas leakage.

[0008] Therefore, to prevent gas leakage between the plastic bushing and the metal boss, the boss used to regulate airflow may have to be made of a high-strength metal material. In this case, the connection at the joint between the plastic bushing and the metal boss directly affects the product's performance. In at least some implementations, only a simple connection structure may be used at the joint between the plastic bushing and the metal boss, thereby increasing the risk of leakage at the seam during long-term charging / discharging processes. Summary of the Invention

[0009] This disclosure aims to provide a boss for a hydrogen tank that can achieve a primary high-pressure seal by utilizing the pressure applied by the stored fluid, and a secondary seal by generating a constant pressure in a low-pressure area formed due to fluid leakage and pressure release, thereby ensuring excellent sealing performance of the boss structure.

[0010] According to one or more exemplary embodiments of this disclosure, a boss for a hydrogen tank may include a nozzle boss and a fastener. The nozzle boss may include: a neck extending a predetermined length; and a flange disposed at a bottom portion of the neck. A chamber may be formed within the neck. The flange may be integrally formed with the neck and configured to engage with a bushing of the hydrogen tank. The fastener may be installed at a lower region of the flange and contact the seam between the nozzle boss and the bushing to prevent fluid leakage through the seam.

[0011] The flange may taper in a first cascade profile in the lower region. The inner surface of the fastener may be mounted to contact the outer surface of the flange. The inner surface of the fastener may have a second cascade profile that matches the first cascade profile of the flange.

[0012] A first thread is formed on the surface of the lowest step of the first stepped profile of the flange. A second thread is formed on the surface of the lowest step of the second stepped profile of the fastener. The fastener is threadedly fastened to the flange via the first and second threads.

[0013] The fastener may include: a nut-shaped portion forming the lowermost step of a second stepped profile of the fastener; and an extension wall disposed on the top of the nut-shaped portion and tapering along the second stepped profile. A second thread may be formed on the inner surface of the nut-shaped portion.

[0014] One or more washers are provided on the extension wall to maintain a seal at the joint after the nut-shaped part is threaded to the flange.

[0015] One or more washers may include: a first O-ring mounted on the inner surface of the extension wall; and a second O-ring mounted on the outer surface of the extension wall.

[0016] An inner annular component may be installed below the first O-ring and on the inner surface of the extension wall. An outer annular component may be installed below the second O-ring and on the outer surface of the extension wall.

[0017] The bushing may include a rib extending from the inner circumferential surface of the bushing to the joint. This rib may contact a second O-ring to maintain a seal at the joint.

[0018] A protrusion may be formed at the upper part of the extended wall, and the protrusion may be inserted into the joint.

[0019] One or more washers may also include a third O-ring installed between the protrusion and the seam.

[0020] According to one or more exemplary embodiments of this disclosure, a boss assembly may include a nozzle boss, a fastener, and a plurality of washers. The nozzle boss may include: a nozzle having a cylindrical shape; and a flange extending radially outward from a bottom portion of the nozzle to engage with a bushing of a gas reservoir at a joint; wherein the flange includes: a first disc-shaped portion disposed at a lower end region of the flange, the first disc-shaped portion having a first diameter; a second disc-shaped portion disposed below the first disc-shaped portion, the second disc-shaped portion having a second diameter smaller than the first diameter; and a third disc-shaped portion disposed below the second disc-shaped portion, the third disc-shaped portion having a third diameter smaller than the second diameter. A first thread may be formed on the outer surface of the third disc-shaped portion. The nozzle may include a gas inlet leading to a gas reservoir. The fastener may be configured to abut against the boss and the bushing to form a seal at the joint. The fastener may include a first annular portion having a first radial thickness. A second thread corresponding to the first thread may be formed on the inner surface of the first annular portion. The fastener may also include a second annular portion having a second radial thickness smaller than the first radial thickness. The second annular portion may be disposed on top of the first annular portion. The fastener may also include a third annular portion having a third radial thickness less than the second radial thickness. The third annular portion may be disposed on top of the second annular portion. A plurality of washers may include: a first washer wedged between the second disc-shaped portion and the second annular portion; a second washer wedged between the second annular portion and the bushing; and a third washer wedged between the third annular portion and the seam. The nozzle and the flange are integrally formed with each other, and the first, second, and third annular portions of the flange are also integrally formed. The first, second, and third annular portions of the fastener may be integrally formed with each other.

[0021] As described above, the boss for a hydrogen tank according to this disclosure can achieve a primary high-pressure seal by utilizing the pressure applied by the stored fluid, and a secondary seal by generating a constant pressure in a low-pressure area formed due to the leakage of fluid and the release of pressure, thereby ensuring that the boss structure has excellent sealing performance. Attached Figure Description

[0022] Figure 1 This is a top plan view showing the structure of the boss for a hydrogen tank according to this disclosure.

[0023] Figure 2 This is an enlarged view showing the main part of the boss for a hydrogen tank according to the present disclosure. Detailed Implementation

[0024] In the following, a boss for a hydrogen tank according to one or more exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings.

[0025] However, the spirit of this disclosure is not limited to the exemplary embodiments described herein, but can be implemented in various different forms. Within the scope of the spirit of this disclosure, one or more components in the exemplary embodiments may be selectively combined and used interchangeably.

[0026] Furthermore, unless otherwise specifically and explicitly defined and stated, the terms (including technical and scientific terms) used in the exemplary embodiments of this disclosure are to be interpreted as having the meaning commonly understood by one of ordinary skill in the art to which this disclosure pertains. The meanings of common terms, such as those defined in dictionaries, can be interpreted in conjunction with the contextual meaning of the relevant art.

[0027] Furthermore, the terminology used in the exemplary embodiments of this disclosure is for the purpose of explaining the exemplary embodiments and not for limiting this disclosure.

[0028] For the purposes of this application and claims, the exemplary phrases “at least one of A; b; or C” or “at least one of A, B, or C” are used, which means “at least one A, or at least one B, or at least one C, or any combination of at least one A, at least one B, and at least one C.” Furthermore, as used herein, exemplary phrases such as “A, B, or C,” “at least one of A, B, and C,” “at least one of A, B, or C,” etc., may represent each listed item or all possible combinations of listed items. For example, “at least one of A or B” may refer to (1) at least one A; (2) at least one B; or (3) at least one A and at least one B.

[0029] Furthermore, terms such as first, second, A, B, (a) and (b) may be used to describe the constituent elements of exemplary embodiments of this disclosure.

[0030] These terms are used only for the purpose of distinguishing one component from another, and the nature, sequence, or order of the components are not limited by these terms.

[0031] Furthermore, when a component is described as “connected,” “joined,” or “attached” to another component, a component may be directly connected, joined, or attached to another component, or connected, joined, or attached to another component through another component in between.

[0032] Furthermore, the expression "one component is positioned above or below another component" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are positioned or arranged between the two components. The expression "above or below" can refer to both the downward and upward directions of a component.

[0033] In at least some embodiments, different methods have been proposed to prevent gas from leaking from the pressure vessel, such as forming threads on the boss and then tightening the boss, using a physical bonding structure with insert members, and using a chemical bonding structure with thermal fusion.

[0034] However, the physical connection structure of the bushing and boss in these implementations may have disadvantages, including the need for a complex boss structure, increased boss weight, increased cost of manufacturing the boss, and an increased number of complex processes. Furthermore, the physical connection structure in these embodiments may be susceptible to fatigue loads caused by repetitive processes, such as refueling.

[0035] Furthermore, another problem is that when the seals deteriorate during prolonged use, causing gas leaks, the entire container (which might otherwise have had a remaining service life) may have to be discarded. This can result in significant economic losses. This disclosure will describe ways to mitigate or eliminate these problems through one or more exemplary embodiments.

[0036] Figure 1 This is a top plan view showing the structure of the boss for the hydrogen tank, and Figure 2 This is an enlarged view showing the main part of the boss used for the hydrogen tank.

[0037] As shown in these figures, the boss for the hydrogen tank may include a nozzle boss 100. The nozzle boss 100 may include a neck (also referred to as a neck portion, column, or nozzle) 110 and a flange (also referred to as a flange portion, ridge, lip, edge, or skirt) 120. A chamber (also referred to as a hollow portion, cavity, space, etc.) 111 may be formed within the neck 110. The neck 110 may extend a predetermined length. The flange 120 may be disposed on the neck 110 (e.g., at the bottom portion of the neck 110). The flange 120 may be integrally formed with the neck 110. The flange 120 may extend radially outward from the bottom portion of the neck 110. The flange 120 may be engaged to the bushing 1 by, for example, insertion injection molding. The bushing 1 may have: a filling space (e.g., a storage space) capable of being filled (e.g., storing) a fluid (e.g., hydrogen); and a fastener (also referred to as a seal, gasket, hermetic seal, washer, or stop) 200, mounted in (e.g., around) the end (e.g., lower) region (e.g., end, tip, etc.) of the flange 120 and configured to contact the boundary region (e.g., seam) between the nozzle protrusion 100 and the bushing 1. The fastener 200 may reduce or prevent fluid leakage at or through the boundary region between the nozzle protrusion 100 and the bushing 1.

[0038] The neck 110 can protrude a predetermined length from the inlet side of the bushing 1, which can form the body of the hydrogen tank. The neck 110 can serve as an inlet through which hydrogen enters the interior of the hydrogen tank and is stored in the hydrogen tank. The neck 110 can have a chamber 111 inside the neck 110, and the chamber 111 can serve as a channel through which the hydrogen tank is filled with hydrogen.

[0039] Flange 120 may refer to a component located on the underside of neck 110 (e.g., closer to the interior of the can). Flange 120 may be integrally formed with neck 110 and engage with bushing 1, such that neck 110 is connected to bushing 1. A channel hole (also referred to as a connecting hole) 122 may be formed through flange 120 and connected to a chamber 111 formed in neck 110.

[0040] The flange 120 and the bushing 1 can be joined together, for example, by insert injection molding (also known as insert molding). Insert injection molding can be advantageous because it allows the hydrogen tank to be manufactured quickly and easily. Furthermore, the boundary area (e.g., seam) between the bushing 1 and the flange 120 can be firmly manufactured by insert injection molding, thereby reducing or preventing leakage from the boundary area.

[0041] The end region of flange 120 may be formed in a stepped shape (e.g., having a stepped profile), such that the outer diameter of the end region of flange 120 gradually decreases (e.g., tapers) in a downward direction. The end region of flange 120 may have a stepped structure including a first disc-shaped portion, a second disc-shaped portion disposed below the first disc-shaped portion, and a third disc-shaped portion disposed below the second disc-shaped portion. The diameter of the second disc-shaped portion may be smaller than the diameter of the first disc-shaped portion. The diameter of the third disc-shaped portion may be smaller than the diameter of the second disc-shaped portion. The circular inner wall surface of fastener 200 (also referred to as the inner diameter portion) (described below) is mounted to contact the circular outer wall surface of flange 120 (also referred to as the outer diameter portion), which may be formed in a stepped shape. The stepped (e.g., stepped) shape of the circular inner wall surface of fastener 200 may be a mirror image of the stepped shape of the circular outer wall surface of fastener 200. The stepped (e.g., step) shape of the circular inner wall surface of the fastener 200 can correspond to the shape of the circular outer wall surface of the flange 120. In other words, the stepped profile of the inner surface of the fastener can match the stepped profile of the lower part of the flange.

[0042] The boundary area (e.g., joint) where the flange 120 and the fastener 200 engage with each other can be formed in a stepped (e.g., step) shape to increase the contact area, thereby reducing or preventing leakage from the boundary area and securely sealing the boundary area.

[0043] Threads (e.g., helical ridges) 121 may be formed on the outer surface of flange 120 (e.g., a circular outer wall surface) (e.g., on the surface of the lowest step of the stepped profile of flange 120). Threads 211 (e.g., mating threads) may be formed on the inner surface of fastener 200 (e.g., a circular inner wall surface) (e.g., at the lowest portion of the inner surface of fastener 200) such that fastener 200 and flange 120 can be threadedly fastened and connected to each other.

[0044] Fastener 200 can be configured to abut against a boss (e.g., nozzle boss 100) and bushing 1 to form a seal at a joint (e.g., a boundary region). The fastener can have a stepped structure including a first annular portion, a second annular portion, and a third annular portion. The first annular portion can have a first radial thickness. A thread corresponding to the thread of flange 120 can be formed on the inner surface of the first annular portion. The second annular portion can have a second radial thickness less than the first radial thickness. The second annular portion can be disposed on top of the first annular portion. The third annular portion can have a third radial thickness less than the second radial thickness. The third annular portion can be disposed on top of the second annular portion.

[0045] By utilizing a structure in which the boundary region (e.g., a seam) is formed in a stepped shape and fasteners 200 are threaded and connected to the outer surface of the end of the flange 120, multiple points on the flange 120 can be pressed (e.g., compressed) toward the bushing 1 simply by the shape of the fasteners 200 in the boundary region. Therefore, the boundary region can be pressed (e.g., compressed) so that the portion between the bushing 1 and the flange 120 can be securely sealed.

[0046] Meanwhile, the fastener 200 may include a nut-shaped portion 210 and an extension wall (also referred to as an extension member) 220. Threads 211 are formed on the inner surface of the nut-shaped portion. The extension wall extends from the upper surface of the nut-shaped portion 210 along the height direction of the flange 120 and is formed in a stepped shape, such that the inner and outer diameters of the extension wall 220 decrease in the upward direction. The extension wall 220 and the nut-shaped portion 210 may be integrally formed with each other.

[0047] The outer surface of the nut-shaped portion 210 is formed in a polygonal or complex curved surface shape (e.g., a cross-section) such that the nut-shaped portion 210 can be rotated by a single tool (such as a wrench). The nut-shaped portion 210 may be a component threaded to the end of the flange 120. A thread identical to (e.g., a thread corresponding to or matching the flange thread) to the threaded thread of the flange 120 may be formed on the inner surface of the nut-shaped portion 210, such that the nut-shaped portion 210 can be threaded to the end of the flange 120.

[0048] The extension wall 220 is integrally formed with the nut-shaped portion 210. As described above, the extension wall 220 is a stepped member that extends from the upper surface of the nut-shaped portion 210 along the height direction of the flange 120, such that the inner diameter and outer diameter of the extension wall 220 decrease in the upward direction.

[0049] Since the extension wall 220 is provided on the upper surface of the nut-shaped portion 210 and is formed in a stepped shape, the inner diameter and outer diameter of the extension wall 220 decrease in the upward direction in the height direction of the flange 120. Therefore, when the nut-shaped portion 210 is threaded to the end of the flange 120, the flange 120 can be pressed at multiple points by the stepped inner diameter.

[0050] In addition, the extension wall 220 may include one or more washers (also referred to as sealing retainers, rings, or O-rings) 230 that, when the nut-shaped portion 210 is threaded to the flange 120, are capable of maintaining a seal (e.g., forming a seal) in the boundary region (e.g., a joint). The one or more washers 230 may be made of flexible (e.g., compressible) and / or impermeable materials (such as rubber).

[0051] Gasket 230 is mounted on the inner and outer walls of extension wall 220 and prevents fluid stored inside bushing 1 from leaking through gaps that may be formed between flange 120 having a stepped outer diameter and extension wall 220 having a stepped outer diameter, and also between extension wall 220 and bushing 1.

[0052] The gasket 230 may include a first O-ring 231 mounted on the inner circular surface of the extension wall 220 and a second O-ring 232 mounted on the outer circular surface of the extension wall 220. The first O-ring 231 may be disposed between the extension wall 220 and the flange 120, and the second O-ring 232 may be disposed between the extension wall 220 and the bushing 1, thereby maintaining a seal.

[0053] Rib (also referred to as rib member) 1a may protrude from the inner circumferential surface of bushing 1 toward the boundary region (e.g., seam) such that second O-ring 232 can be disposed between extension wall 220 and bushing 1. Rib 1a may be configured to contact and protrude from second O-ring 232 to maintain a seal.

[0054] Furthermore, the outer surface of the flange 120 that contacts the first O-ring 231 and the outer surface of the rib 1a that contacts the second O-ring 232 gradually taper in the upward direction, so that the outer surfaces of the flange 120 and the rib 1a become closer to the side surface of the extension wall 220 in the height direction of the extension wall 220.

[0055] Since the outer surfaces of the flange 120 and the rib 1a are tapered, when the nut-shaped portion 210 is fastened to the end of the flange 120 and the extension wall 220 is pressed (e.g., against) the boundary region (e.g., the seam) (e.g., afterwards), the first O-ring 231 and the second O-ring 232 can be further attached tightly to the outer surfaces of the flange 120 and the rib 1a, respectively.

[0056] Furthermore, the inner annular member (also referred to as the inner pressing member) 240 and the outer annular member (also referred to as the outer pressing member) 250 can be mounted on the inner and outer walls of the extension wall 220, respectively, and positioned below the first O-ring 231 and the second O-ring 232. The inner and outer annular members can be made of a material that is more rigid (e.g., incompressible) than the material of one or more washers 230 (e.g., the first O-ring 231 and the second O-ring 232).

[0057] The inner annular member 240 can contact the first O-ring 231 and press the first O-ring 231 against the flange 120, and the outer annular member 250 can contact the second O-ring 232 and press the second O-ring 232 against the bushing 1, thereby reliably achieving a seal.

[0058] The first O-ring 231 and the second O-ring 232 are respectively mounted on the inner and outer surfaces of the extension wall 220, and the inner annular member 240 and the outer annular member 250 are respectively mounted on the inner and outer surfaces of the extension wall 220. Therefore, when an internal pressure of 700 bar or higher is generated below the inner annular member 240 and the outer annular member 250, the inner annular member 240 and the outer annular member 250 push (e.g., compress) the first O-ring 231 and the second O-ring 232 upwards, thereby achieving a secure seal, and a primary seal can be achieved by utilizing the internal pressure applied by the fluid stored inside the bushing 1.

[0059] Furthermore, a protrusion (also referred to as a projection) 260 is formed at the upper end (e.g., the lower part) of the extension wall 220. The protrusion 260 protrudes in the height direction of the extension wall 220 and inserts into a boundary region (e.g., a seam). A third O-ring 270 can be installed in the boundary region into which the protrusion 260 is inserted. In other words, the third O-ring 270 can be installed (e.g., wedged) between the protrusion and the boundary region (e.g., the seam).

[0060] One or more washers 230 may include a first washer (e.g., a first O-ring 231), a second washer (e.g., a second O-ring 232), and a third washer (e.g., a third O-ring 270). The first washer may be wedged between the second disc portion and the second annular portion. The second washer may be wedged between the second annular portion and the bushing. The third washer may be wedged between the third annular portion and the joint (e.g., a boundary region).

[0061] With the above configuration, the nut-shaped portion 210 can be rotated and connected to the flange 120 such that when the nut-shaped portion 210 is tightened to the end of the flange 120, the torque value is greater than or equal to the torque threshold (e.g., 35 Nm). Therefore, the third O-ring 270 is pressed (e.g., compressed) by the protrusion 260 at a threshold pressure value (e.g., 857 bar) or greater, so that a secondary seal can be achieved through internal pressure.

[0062] Even if the internal pressure inside the bushing 1 drops due to leakage of the fluid stored in the bushing 1 or due to the use of the fluid stored in the bushing 1, the second seal can always maintain excellent sealing performance.

[0063] The boss for a hydrogen tank configured as described above according to this disclosure can achieve a primary high-pressure seal by utilizing the pressure applied by the stored fluid, and a secondary seal by generating a constant pressure in a low-pressure area formed due to fluid leakage and pressure release, thereby ensuring that the boss structure has excellent sealing performance.

[0064] The boss for a hydrogen tank may include: a nozzle boss, comprising: a neck portion having a hollow portion and extending a predetermined length; and a flange portion disposed on one side of the neck portion, integrally formed with the neck portion and configured to engage with a bushing having an inlet space capable of being filled with fluid; and a seal mounted in an end region of the flange portion and configured to contact a boundary region between the nozzle boss and the bushing to prevent fluid leakage from the boundary region between the nozzle boss and the bushing.

[0065] The end region of the flange portion can be formed into a stepped shape, such that the outer diameter of the end region of the flange portion decreases in the downward direction, and the inner diameter portion of the seal that is installed in contact with the outer diameter portion of the flange portion can be formed into a stepped shape corresponding to the outer diameter of the flange portion.

[0066] A thread can be formed on the outer diameter portion of the lowest part of the flange portion, and a thread can be formed on the inner surface of the lowest part of the seal, and the seal can be threaded to the flange portion.

[0067] The seal may include: a nut member having threads formed on its inner surface; and an extension member disposed on the upper surface of the nut member, extending in the height direction of the flange portion and formed in a stepped shape, wherein the inner and outer diameters of the extension member decrease in the upward direction.

[0068] The extension member may include a sealing retention device configured to maintain a seal in the boundary area when the nut member is threaded to the flange portion.

[0069] The sealing retention device may include: a first O-ring mounted on the inner diameter portion of the extension member; and a second O-ring mounted on the outer diameter portion of the extension member.

[0070] An inner pressing member and an outer pressing member are respectively provided on the inner diameter portion and the outer diameter portion of the extension member, and the inner pressing member and the outer pressing member are located below the first O-ring and the second O-ring.

[0071] The rib can protrude from the inner circumferential surface of the bushing into the boundary region, so that the rib contacts the second O-ring to maintain a seal.

[0072] The protrusion can be formed at the upper end of the extension member, protruding in the height direction of the extension member and inserted into the boundary area.

[0073] A third O-ring may be provided in the boundary area where the protrusion is inserted.

[0074] While one or more exemplary embodiments that can be implemented by this disclosure have been described above, these exemplary embodiments are merely illustrative and not intended to limit the disclosure. Those skilled in the art will understand that various modifications and applications not described above can be made to this disclosure without departing from its inherent characteristics. For example, the various components specifically described in the exemplary embodiments can be modified and then implemented. Furthermore, it should be understood that differences related to modifications and applications are included within the scope of this disclosure as defined by the appended claims.

[0075] List of reference numerals in the attached diagram:

[0076] 1: Bushing

[0077] 1a: Rib member

[0078] 100: Nozzle boss

[0079] 110: Neck area

[0080] 111: Hollow section

[0081] 120: Flange portion

[0082] 121: Thread

[0083] 122: Connecting hole

[0084] 200: Seal

[0085] 210: Nut component

[0086] 211: Thread

[0087] 220: Extension component

[0088] 230: Sealing retention component

[0089] 231: First O-ring

[0090] 232: Second O-ring

[0091] 240: Internal pressing component

[0092] 250: External pressing component

[0093] 260: Protrusion

[0094] 270: Third O-ring

Claims

1. A boss for a hydrogen tank, the boss comprising: Nozzle boss, the nozzle boss comprising: Neck, extending a predetermined length, wherein a cavity is formed within the neck; and A flange is disposed at the bottom portion of the neck, wherein the flange is integrally formed with the neck and configured to engage with a bushing of the hydrogen tank; and Fasteners are installed in the lower region of the flange and contact the seam between the nozzle boss and the bushing to prevent fluid leakage through the seam.

2. The boss according to claim 1, wherein, The flange tapers in a first stepped profile in the lower region, wherein the inner surface of the fastener is mounted to contact the outer surface of the flange, and wherein the inner surface of the fastener has a second stepped profile that matches the first stepped profile of the flange.

3. The boss according to claim 2, wherein, A first thread is formed on the surface of the lowest step of the first stepped profile of the flange, wherein a second thread is formed on the surface of the lowest step of the second stepped profile of the fastener, and wherein the fastener is threaded to the flange via the first thread and the second thread.

4. The boss according to claim 3, wherein, The fasteners include: A nut-shaped portion, forming the lowermost step of the second stepped profile of the fastener, wherein a second thread is formed on the inner surface of the nut-shaped portion; and An extension wall is provided on the top of the nut-shaped portion and tapers along the second stepped profile.

5. The boss according to claim 4, wherein, One or more washers are provided on the extension wall to maintain a seal at the joint after the nut-shaped portion is threaded onto the flange.

6. The boss according to claim 5, wherein, The one or more washers include: A first O-ring is mounted on the inner surface of the extended wall; and A second O-ring is mounted on the outer surface of the extension wall.

7. The boss according to claim 6, wherein, An inner annular member is installed below the first O-ring and on the inner surface of the extension wall, and an outer annular member is installed below the second O-ring and on the outer surface of the extension wall.

8. The boss according to claim 6, wherein, The bushing includes a rib extending from the inner circumferential surface of the bushing to the joint, wherein the rib contacts the second O-ring to maintain a seal at the joint.

9. The boss according to claim 6, wherein, A protrusion is formed at the upper part of the extended wall, and the protrusion is inserted into the joint.

10. The boss according to claim 9, wherein, The one or more washers also include a third O-ring installed between the protrusion and the seam.

11. A boss assembly, comprising: Nozzle boss, the nozzle boss comprising: A nozzle, having a cylindrical shape, wherein the nozzle includes a gas inlet leading to a gas storage tank; and A flange, extending radially outward from the bottom portion of the nozzle, engages at a joint with the bushing of the gas reservoir, wherein the flange comprises: A first disc-shaped portion is disposed in the lower end region of the flange, and the first disc-shaped portion has a first diameter; A second disc-shaped portion is disposed below the first disc-shaped portion, and the second disc-shaped portion has a second diameter smaller than the first diameter; and A third disc-shaped portion is disposed below the second disc-shaped portion. The third disc-shaped portion has a third diameter smaller than the second diameter, wherein a first thread is formed on the outer surface of the third disc-shaped portion. Fasteners configured to abut against the boss and the bushing to form a seal at the joint, wherein the fasteners comprise: A first annular portion has a first radial thickness, wherein a second thread corresponding to the first thread is formed on the inner surface of the first annular portion; The second annular portion has a second radial thickness smaller than the first radial thickness, wherein the second annular portion is disposed on the top of the first annular portion; and A third annular portion has a third radial thickness smaller than the second radial thickness, wherein the third annular portion is disposed on the top of the second annular portion; and A plurality of washers, said plurality of washers comprising: The first washer is wedged between the second disc-shaped portion and the second annular portion; A second washer is wedged between the second annular portion and the bushing; and The third washer is wedged between the third annular portion and the joint. The nozzle and the flange are integrally formed together, and the first annular portion, the second annular portion, and the third annular portion of the flange are also integrally formed. The first annular portion, the second annular portion, and the third annular portion of the fastener are integrally formed with each other.

Images