JP7472871B2 - tank - Google Patents

Description

The present invention relates to a tank, and in particular to a tank having a seal structure composed of an O-ring and a backup ring.

Tanks such as hydrogen tanks are equipped with a liner having a storage space for storing gas inside and an opening communicating with the storage space, a reinforcing layer formed on the outer periphery of the liner, and a manifold that closes the opening of the liner. The manifold is a lid-like member with an insertion part that is inserted into the opening of the liner. In tanks with such a structure, a sealing structure such as that described in Patent Document 1 below is used to prevent gas from leaking from the gap between the opening of the liner and the insertion part of the manifold.

That is, an outer circumferential groove is provided on the outer circumferential wall of the insertion portion, and an O-ring and backup ring are fitted in the outer circumferential groove in a tightly contacting state, thereby ensuring a seal between the opening of the liner and the insertion portion of the manifold. The backup ring has a long ring body and bias cut surfaces formed on both ends of the ring body and inclined with respect to the longitudinal direction of the ring body. The backup ring is fitted in the outer circumferential groove with the bias cut surfaces butting against each other.

Japanese Patent Application Laid-Open No. 11-315925

However, in a seal structure having such a backup ring, if there is a large variation in the machining dimensions of the backup ring, or if the tank expands significantly radially outward due to gas filling, the butted bias-cut surfaces will become misaligned and pull apart. The portion where the bias-cut surfaces are formed is relatively thin compared to the ring body (in other words, it is a thin-walled portion), so when the bias-cut surfaces pull apart, stress is concentrated in the thin-walled portion, damaging the backup ring and potentially damaging the O-ring as well.

The present invention was made to solve these technical problems, and aims to provide a tank that can prevent damage to the backup ring and sealing member.

The tank according to the present invention is a tank comprising a liner having a cylindrical opening, and a lid-like member having an insertion portion inserted into the opening of the liner so as to close the opening, the insertion portion being provided with an outer circumferential groove, a seal member that seals between the insertion portion and the opening, and a backup ring arranged on the outer side of the tank with respect to the seal member being attached to the outer circumferential groove, the backup ring having an elongated ring body and bias cut surfaces formed on both ends of the ring body and inclined with respect to the longitudinal direction of the ring body, and in an initial state before the tank is filled with gas, the backup ring is attached to the outer circumferential groove with at least a portion of each bias cut surface overlapping a portion of the ring body.

In the tank according to the present invention, in the initial state before the tank is filled with gas, the backup ring is attached to the outer circumferential groove with at least a portion of each bias cut surface overlapping a portion of the ring body. Therefore, even if the bias cut surfaces are misaligned in a direction that pulls them apart, it is possible to suppress stress concentration in the relatively thin portions where the bias cut surfaces are formed, as in the conventional case. Therefore, damage to the backup ring and the seal member can be prevented.

In the tank according to the present invention, of the two bias-cut surfaces, it is preferable that the tip portion of the bias-cut surface adjacent to the seal member is chamfered, rounded, or covered with a cap member. Since the tip of the bias-cut surface is sharp, there is a possibility that the seal member will be damaged. By chamfering the tip portion of the bias-cut surface adjacent to the seal member, rounding, or covering it with a cap member in this way, damage to the seal member can be prevented.

In the tank according to the present invention, it is preferable that the outer peripheral groove has a tapered bottom portion that expands from the outside to the inside of the tank, and the backup ring has a tapered portion that corresponds to the tapered bottom portion of the outer peripheral groove. When the inside of the tank is filled with gas, a pressing force is generated by the internal pressure that presses the seal member and the backup ring against the outside of the tank. By providing the outer peripheral groove with a tapered bottom portion that expands from the outside to the inside of the tank in this way, and providing the backup ring with a tapered portion that corresponds to the tapered bottom portion of the outer peripheral groove, it is possible to prevent the backup ring from protruding from the gap between the opening of the liner and the insertion portion of the manifold. As a result, the effect of preventing damage to the backup ring can be further improved.

The present invention makes it possible to prevent damage to the backup ring and the seal member.

FIG. 2 is a partial cross-sectional view showing a main part of the tank according to the embodiment. FIG. 2 is an enlarged cross-sectional view showing a portion A in FIG. FIG. 1A is a perspective view showing a backup ring that is attached to an outer peripheral groove of a manifold in an initial state, and FIG. 1B is a front view showing the positions of bias cut surfaces of the backup ring that is attached to the outer peripheral groove of a manifold in an initial state. FIG. 1A is a perspective view showing a backup ring that is attached to an outer peripheral groove of a manifold in an initial state, and FIG. 1B is a front view showing the positions of bias cut surfaces of the backup ring that is attached to the outer peripheral groove of a manifold in an initial state. FIG. 1A is a perspective view showing a backup ring that is attached to an outer peripheral groove of a manifold in an initial state, and FIG. 1B is a front view showing the positions of bias cut surfaces of the backup ring that is attached to the outer peripheral groove of a manifold in an initial state. FIG. 1A is a perspective view showing a conventional backup ring that is attached to an outer peripheral groove of a manifold in an initial state, and FIG. 1B is a front view showing the positions of bias-cut surfaces of the conventional backup ring that is attached to an outer peripheral groove of a manifold in an initial state. FIG. 1A is a diagram showing an example in which the tip portion of the bias-cut surface is chamfered, FIG. 1B is a diagram showing an example in which the tip portion of the bias-cut surface is rounded, and FIG. 1C is a diagram showing an example in which the tip portion of the bias-cut surface is covered with a cap member.

Below, an embodiment of the 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, but 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), LNG (liquefied natural gas), LPG (liquefied petroleum gas), and the like.

Figure 1 is a partial cross-sectional view showing the main parts of a tank according to an embodiment. The tank 1 of this embodiment is a high-pressure gas storage container that is approximately cylindrical with dome-shaped rounded ends, and includes a liner 10 that has gas barrier properties, and a reinforcing layer 20 that is formed to cover the outer periphery of the liner 10.

The liner 10 is formed from a resin material that has gas barrier properties against hydrogen gas, and has a cylindrical body 11 and a pair of dome sections 12 (only one dome section is shown in FIG. 1) provided at both ends of the body 11 in the axial L direction. The axial L direction of the body 11 is the axial L direction of the tank 1. In the following description, this "axial L direction of the tank" will be abbreviated to "axial L direction".

The dome portion 12 is hemispherical. A cylindrical opening 13 is provided at the end of the dome portion 12 opposite the body portion 11. The opening 13 has an outer diameter smaller than the dome portion 12 and is positioned so as to protrude from the dome portion 12 along the axis L direction. This opening 13 functions as a fill port for filling the tank 1 with hydrogen gas, or as an exhaust port for discharging the hydrogen gas stored in the tank 1.

The liner 10 is integrally formed by rotational blow molding using a resin such as polyethylene or nylon. The liner 10 may also be formed from a light metal such as aluminum instead of resin. Furthermore, instead of a manufacturing method for integral molding such as rotational blow molding, the liner 10 may be formed by joining multiple divided members by injection or extrusion molding or the like.

The reinforcing layer 20 is formed of fiber-reinforced resin. In this embodiment, carbon fiber-reinforced resin (CFRP) is used as the fiber-reinforced resin. This carbon fiber-reinforced resin forms the reinforcing layer 20 by covering the entire liner 10, including the opening 13. The thickness of the reinforcing layer 20 increases from the body portion 11 side to the dome portion 12 side of the liner 10. The thickness of the portion of the reinforcing layer 20 covering the opening 13 is approximately the same.

A nozzle 30 is attached to the outside of the reinforcing layer 20 that covers the opening 13. The nozzle 30 is made of a metal material such as stainless steel or aluminum and machined into a cylindrical shape. It has a cylindrical nozzle body 31 that extends along the axis L, and a flange 32 that is connected to one end of the nozzle body 31 and protrudes in the radial direction.

The outer periphery of the base body 31 is formed with a male thread 33 that screws into the manifold 40 described below. The inner periphery of the base body 31 is formed with a saw-like locking claw 34. The base 30 is fixed to the reinforcing layer 20 by the locking claw 34 biting into the outer periphery of the reinforcing layer 20.

The flange portion 32 serves to increase the strength of the nozzle 30 and to regulate the screwing depth of the manifold 40 when screwed into the manifold 40, and is formed integrally with the nozzle body portion 31.

A manifold 40 is attached to the opening 13 of the liner 10. The manifold 40 corresponds to the "lid-like member" described in the claims, and is, for example, a member for connecting multiple tanks 1. This manifold 40 has a substantially disk-shaped main body 41, a side wall 42 that connects to the outer periphery of the main body 41 and extends in the axial L direction, and an insertion portion 43 that is located in the center of the main body 41 and protrudes to the same side as the extension side of the side wall 42.

The main body 41 is the portion that corresponds to the top plate of the manifold 40. The inner surface of the main body 41 is the abutment surface that abuts against the opening 13, the reinforcing layer 20, and the end face of the nozzle 30. A female thread 46 that screws into the male thread 33 of the nozzle 30 is formed on the inner circumference of the side wall 42.

The insertion portion 43 is inserted into the opening 13 to close the opening 13, and has a generally cylindrical shape. The outer diameter of the insertion portion 43 is slightly smaller than the inner diameter of the opening 13. A slit 44 extending along the axis L is provided in the center of the insertion portion 43. This slit 44 is a structure for deforming the insertion portion 43 to make it easier to insert the insertion portion 43 into the opening 13. In addition, an outer peripheral groove 45 is provided on the outer peripheral wall of the insertion portion 43. An O-ring 50 that seals between the insertion portion 43 and the opening 13 and a backup ring 51 that is arranged outside the tank 1 more than the O-ring 50 are attached in close contact with the outer peripheral groove 45.

2 is an enlarged cross-sectional view of part A in FIG. 1. As shown in FIG. 2, the outer peripheral groove 45 has a pair of wall surfaces (outer wall surface 45a, inner wall surface 45b) facing each other in the axial L direction, and a tapered bottom portion 45c and a parallel bottom portion 45d that are disposed between the wall surfaces and form the bottom portion of the outer peripheral groove 45. More specifically, of the pair of wall surfaces, the outer wall surface 45a is disposed on the outside of the tank 1, and the inner wall surface 45b is disposed on the inside of the tank 1. The tapered bottom portion 45c is formed so as to connect with the outer wall surface 45a and expand toward the inner wall surface 45b side (i.e., from the outside to the inside of the tank 1). The parallel bottom portion 45d is formed parallel to the axial L direction so as to connect the tapered bottom portion 45c and the inner wall surface 45b.

The O-ring 50 corresponds to the "sealing member" described in the claims, and is made of, for example, a rubber material. The O-ring 50 is mounted in the outer circumferential groove 45 in a state compressed by the opening 13 and the parallel bottom portion 45d, ensuring a seal between the opening 13 and the insertion portion 43.

The backup ring 51 is a so-called ended ring, and has a trapezoidal cross section with a tapered portion 514 that corresponds to the tapered bottom portion 45c of the outer circumferential groove 45. The tapered portion 514 has approximately the same inclination angle as the tapered bottom portion 45c of the outer circumferential groove 45. The backup ring 51 is made of, for example, a fluorine-based resin material or nylon 46, which has a smaller friction coefficient than the O-ring 50 and is less prone to elastic deformation.

Figure 3(a) is a perspective view showing the backup ring attached to the outer peripheral groove of the manifold in the initial state, and Figure 3(b) is a front view showing the position of the bias cut surfaces of the backup ring attached to the outer peripheral groove of the manifold in the initial state. In this embodiment, the initial state refers to the state before the tank 1 is filled with gas. Also, in Figure 3 and Figures 4 to 6 described later, only the backup ring 51 in the initial state is shown to make it easier to understand the state of the backup ring 51 attached to the outer peripheral groove 45.

As shown in FIG. 3, the backup ring 51 has an elongated ring body 511 and bias cut surfaces 512, 513 formed on both ends of the ring body 511 and inclined relative to the longitudinal direction of the ring body 511.

Here, we explain how we came to this invention.

As shown in FIG. 6, the backup ring 51A that is conventionally mounted in the outer peripheral groove 45 has an elongated ring body 511A and bias cut surfaces 512A, 513A that are formed on both ends of the ring body 511A and are inclined relative to the longitudinal direction of the ring body 511A, as in the backup ring 51 of this embodiment. The inner diameter of the backup ring 51A is formed to be approximately the same as the outer diameter of the outer peripheral groove 45. The portion where the bias cut surfaces 512A, 513A are formed is a thin portion that is relatively thin compared to the ring body 511A, but since the entire bias cut surface 512A and the entire bias cut surface 513A are butted against each other when mounted in the outer peripheral groove 45, the thickness is approximately the same throughout the entire backup ring 51A.

However, as described above, with such a backup ring 51A, if there is a large variation in the machining dimensions of the backup ring 51A, or if the tank 1 expands significantly radially outward due to gas filling, the butted bias cut surfaces 512A, 513A will be misaligned in the direction of pulling away from each other. Because the portions where the bias cut surfaces 512A, 513A are formed are thin-walled portions, when the bias cut surfaces 512A, 513A are pulled away from each other, stress will concentrate in these thin-walled portions, damaging the backup ring 51A and causing the O-ring 50 to also be damaged.

To solve this problem, in this embodiment, in the initial state, the backup ring 51 is attached to the outer circumferential groove 45 with at least a portion of each bias cut surface 512, 513 overlapping a portion of the ring body 511.

More specifically, the backup ring 51 of this embodiment is mounted in the outer circumferential groove 45 in a state where a part of the bias cut surface 512 and a part of the bias cut surface 513 overlap a part of the ring body 511 when viewed from the axial L direction (see FIG. 3(a)). As a result, when viewed from the axial L direction, a part where a part of the bias cut surface 513 overlaps a part of the ring body 511, a part where the remaining part of the bias cut surface 513 overlaps a part of the bias cut surface 512, and a part where the remaining part of the bias cut surface 512 overlaps a part of the ring body 511 are formed from the tip of the bias cut surface 513 to the tip of the bias cut surface 512. These overlapping parts form a thick portion that is thicker than other parts of the ring body 511 in the axial L direction (see FIG. 3(b)). In this embodiment, the tips of the bias cut surfaces 512 and 513 refer to the most pointed ends of both ends of the bias cut surfaces 512 and 513.

In the initial state, the backup ring 51 may be attached to the outer circumferential groove 45 with the entire bias cut surface 512 and the entire bias cut surface 513 overlapping with a portion of the ring body 511 when viewed from the axial L direction. For example, as shown in FIG. 4, when viewed from the axial L direction, from the tip of the bias cut surface 513 to the tip of the bias cut surface 512, there are formed a portion where the entire bias cut surface 513 overlaps with a portion of the ring body 511, a portion where the ring bodies 511 overlap with each other, and a portion where the entire bias cut surface 512 overlaps with a portion of the ring body 511. These overlapping portions form thick portions that are thicker than other portions of the ring body 511 in the axial L direction.

Furthermore, in the initial state, the backup ring 51 may be attached to the outer circumferential groove 45 with the entire bias cut surface 512 and the entire bias cut surface 513 overlapping with a portion of the ring body 511 when viewed from the radial direction of the tank 1 perpendicular to the axial L direction. For example, as shown in FIG. 5, when viewed from the radial direction of the tank 1, there are formed, from the tip of the bias cut surface 513 to the tip of the bias cut surface 512, a portion where the entire bias cut surface 513 overlaps with a portion of the ring body 511, a portion where the ring bodies 511 overlap with each other, and a portion where the entire bias cut surface 512 overlaps with a portion of the ring body 511. These overlapping portions form thick portions that are thicker than other portions of the ring body 511 in the radial direction of the tank 1.

In the tank 1 configured as described above, in the initial state, the backup ring 51 is attached to the outer circumferential groove 45 with the bias cut surface 512 and the bias cut surface 513 partially or entirely overlapping with a portion of the ring body 511, forming a thick-walled portion that is thicker than other portions of the ring body 511 in the axial L direction or radial direction of the tank 1. Therefore, even if a positional shift occurs in the direction in which the bias cut surfaces 512, 513 are pulled away from each other, stress concentration in the thin-walled portion can be suppressed as in the conventional case, preventing damage to the backup ring 51 and further preventing damage to the O-ring 50.

When the tank 1 is filled with gas, the internal pressure generates a pressing force that presses the O-ring 50 and the backup ring 51 against the outside of the tank 1. In this embodiment, the outer circumferential groove 45 is provided with a tapered bottom 45c that expands from the outside to the inside of the tank 1, and the backup ring 51 is provided with a tapered portion 514 that corresponds to the tapered bottom 45c, thereby preventing the backup ring 51 from protruding from the gap between the opening 13 of the liner 10 and the insertion portion 43 of the manifold 40. As a result, the effect of preventing damage to the backup ring 51 can be further improved.

In addition, since the tips of the bias cut surfaces 512 and 513 are sharp, there is a problem that they may damage the adjacent O-ring 50. In order to solve this problem, for example, the tip portion of the bias cut surface 512 of the two bias cut surfaces 512 and 513 that is adjacent to the O-ring 50 can be chamfered (see FIG. 7(a)), rounded (see FIG. 7(b)), or covered with a cap member 60 (see FIG. 7(c)), thereby preventing damage to the O-ring 50 by the tip of the bias cut surface 512. In addition, the cap member 60 is formed, for example, from a resin material that is harder than the backup ring 51.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, and various design changes can be made without departing from the spirit of the present invention as described in the claims.

1: Tank, 10: Liner, 11: Body, 12: Dome, 13: Opening, 20: Reinforcement layer, 30: Cap, 31: Cap body, 32: Flange, 33: Male thread, 34: Locking claw, 40: Manifold (lid-like member), 41: Body, 42: Side wall, 43: Insertion, 44: Slit, 45: Outer circumferential groove, 45a: Outer wall, 45b: Inner wall, 45c: Tapered bottom, 45d: Parallel bottom, 46: Female thread, 50: O-ring (sealing member), 51: Backup ring, 60: Cap member, 511: Ring body, 512, 513: Bias cut surface, 514: Tapered portion

Claims (3)

A cylindrical tank comprising a liner having a cylindrical opening, and a lid-like member having an insertion portion that is inserted into the opening of the liner so as to close the opening,
The insertion portion is provided with an outer circumferential groove,
a seal member that seals between the insertion portion and the opening, and a backup ring that is disposed outside the tank relative to the seal member, the backup ring being attached to the outer circumferential groove;
The backup ring has an elongated ring body and bias cut surfaces formed on both ends of the ring body and inclined with respect to the longitudinal direction of the ring body,
a tank characterized in that, in an initial state before the tank is filled with gas, the backup ring is attached to the outer peripheral groove in a state in which each bias cut surface entirely overlaps a portion of the ring body when viewed in a radial direction perpendicular to an axial direction of the tank. The tank according to claim 1, wherein the tip portion of the bias cut surface adjacent to the seal member of the two bias cut surfaces is chamfered, rounded, or covered with a cap member. The outer circumferential groove has a tapered bottom portion that widens from the outside to the inside of the tank,
3. The tank according to claim 1, wherein the backup ring has a tapered portion corresponding to the tapered bottom portion of the outer circumferential groove.

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