Patent Description:
Generally, a compressed natural gas (CNG) vehicle or a hydrogen fuel cell vehicle includes a high-pressure vessel mounted therein, by which a fuel in an evaporated state is high-pressurized and stored.

The high-pressure vessel includes a plastic liner, a composite material layer covering the plastic liner, and a metallic nozzle boss. For weight reduction, the plastic liner is made of a plastic material such as high-density polyethylene, polypropylene, or polyester resin, the composite material layer made by mixing carbon fiber or glass fiber with polymer resin such as epoxy resin for strength maintenance is combined with the plastic liner so as to cover a surface of the plastic liner, and the nozzle boss is manufactured of a metallic material so as to be securely combined with a regulator or a valve (hereinbelow, referred to as a valve), which is manufactured of the metallic material.

Meanwhile, since the plastic liner and the metallic nozzle boss are made of different materials, an adhesive cannot be used so as to combine the plastic liner with the metallic nozzle. Accordingly, maintaining airtightness between the plastic liner and the metallic nozzle boss is an important issue determining the performance and stability of the high-pressure vessel.

Pressure in the high-pressure vessel is normally a high pressure of 700ba, and when the airtightness between the plastic liner and the metallic nozzle boss is lowered, a high-pressure gas stored in the high-pressure vessel leaks to outside, and particularly, the nozzle boss is separated from the plastic liner by the high-pressure gas, which may cause an accident.

As shown in <FIG>, according to a conventional high-pressure vessel showing a portion on which the plastic liner and the nozzle boss are combined with each other, the plastic liner <NUM> and the metallic nozzle boss <NUM> are configured to be combined with each other by injection molding. That is, when the plastic liner <NUM> is injection-molded after the metallic nozzle boss <NUM> manufactured previously is put in an injection mold, the plastic liner <NUM> and the metallic nozzle boss <NUM> are combined with each other.

Due to the characteristics of an injection combination, the plastic liner <NUM> and the metallic nozzle boss <NUM>, which are made of different materials, cannot be perfectly combined with each other and accordingly, a minute gap between the plastic liner <NUM> and the metallic nozzle boss <NUM> occurs.

When there is a gap between the plastic liner <NUM> and the metallic nozzle boss <NUM>, the high-pressure gas in the vessel leaks through the gap between the plastic liner <NUM> and the metallic nozzle boss <NUM> to the outside.

Accordingly, according to the conventional high-pressure vessel, a lower fastening member <NUM>, which is additionally manufactured, is configured to be combined with the metallic nozzle boss <NUM> so as to remove the gap between the plastic liner <NUM> and the metallic nozzle boss <NUM>.

The lower fastening member <NUM> functions to press an end part of the plastic liner <NUM> toward the metallic nozzle boss <NUM> so as to bring the plastic liner into close contact with the metallic nozzle boss.

The lower fastening member <NUM> is made of a metallic material so as to be securely fastened to the metallic nozzle boss <NUM> and is normally screwed to the metallic nozzle boss.

However, since the plastic liner <NUM> and the metallic lower fastening member <NUM> are respectively made of different materials, a gap between the plastic liner <NUM> and the lower fastening member <NUM> occurs, and the high-pressure gas in the vessel leaks through the gap between the plastic liner <NUM> and the lower fastening member <NUM> and through the gap between the plastic liner <NUM> and the metallic nozzle boss <NUM> to an outside of the plastic liner <NUM>.

To prevent this, a rubber sealing member <NUM> (an O-ring) may be combined with the lower fastening member <NUM> so as to remove the gap between the plastic liner <NUM> and the lower fastening member <NUM>.

However, when the rubber sealing member <NUM> is continuously pressurized by the high-pressure gas, durability thereof lowers rapidly and accordingly, the leak of the high-pressure gas to the outside cannot be perfectly prevented.

In addition, the life of the rubber sealing member <NUM> is normally a short period of four to five years, and is further shortened particularly when pressure of the high-pressure gas is continuously applied to the rubber sealing member. In addition, since the life of a vehicle having the high-pressure vessel mounted therein is longer than the life of the sealing member <NUM>, the high-pressure vessel is required to be periodically replaced due to the durability reduction of the sealing member <NUM>.

That is, in a structure of the conventional high-pressure vessel, the lower fastening member <NUM> and the sealing member <NUM> are used to remove the gap between the plastic liner <NUM> and the metallic nozzle boss <NUM>, which are made of different materials, whereby the number of components, a weight, a cost, and man-hours are increased. Particularly, when the durability of the sealing member <NUM> lowers since the sealing member <NUM> is made of a rubber material, which has short life, the high-pressure gas in the vessel still leaks to the outside and due to the sealing member <NUM> having the lowered durability, the high-pressure vessel is required to be periodically replaced.

Reference numerals <NUM> and <NUM> shown in <FIG>, which are not described, are the composite material layer and an upper fastening member, respectively.

As a related conventional art, there is <CIT>.

<CIT> discloses a pressure vessel for storing liquid or gaseous media. The pressure vessel comprises a plastic inner vessel, at least one neck piece connected thereto as a separate piece, said neck piece being arranged on the vessel neck in the area of the vessel opening, and a support casing that at least partially encloses the plastic inner vessel and the neck piece. The neck piece is provided with means for accommodating a connection fitting. The pressure vessel is characterized by an insert, which forms at least part of the vessel neck and which forms a sealing seat for the fitting to be inserted into the neck piece.

<CIT> discloses a pressure vessel that includes a liner, a composite shell covering the liner, and at least one boss assembly having a metal boss. The metal boss is positioned at respective openings through the liner and the composite shell. A plastic layer is formed between the liner and the metal boss. The plastic layer adheres to both the metal boss and the liner to form a seal at the interface between the metal boss and liner. The plastic layer further increases a torque strength of the metal boss.

The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.

The present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a high-pressure vessel for a vehicle, whereby an airtightness structure between a plastic liner and a metallic nozzle boss is improved such that high-pressure gas in the vessel is fundamentally prevented from leaking to outside of the plastic liner.

In order to accomplish the above object, the present invention provides a high-pressure vessel for a vehicle, the high-pressure vessel including: a plastic liner including a through hole provided thereon; a plastic sealing member, a portion of which is positioned in the through hole and a remaining portion of which overlaps with the plastic liner, wherein the portion overlapping with the plastic liner is combined with the plastic liner by thermal bonding; and a metallic nozzle boss combined with the plastic sealing member so as to cover the portion of the plastic sealing member overlapping with the plastic liner; a composite material layer combined with the plastic liner and the metallic nozzle boss so as to cover the plastic liner and the metallic nozzle boss; the high-pressure vessel for a vehicle wherein the plastic sealing member includes a cylindrical part positioned in the through hole of the plastic liner and protruding in an outer side direction of the plastic liner, and a wing part of a circular plate shape provided to bend so as to correspond a shape of the plastic liner while extending in a radial direction from an end of the cylindrical part and a predetermined section of which is combined with an outer surface of the plastic liner by the thermal bonding; wherein the metallic nozzle boss is screwed to the plastic sealing member; and wherein a major portion of a lower surface of the metallic nozzle boss , which faces the plastic liner, is in contact with the plastic sealing member and only some portion thereof is in contact with the plastic liner.

The plastic liner may be made of a plastic resin by blow molding and be combined with the plastic sealing member by the thermal bonding during the blow molding of the plastic liner.

The wing part may include an inclined part provided on an end part thereof so as to incline toward a protruding direction of the cylindrical part, wherein the inclined part of the wing part may be provided to have the same shape as an inclined part of the plastic liner, and the inclined part of the wing part and the inclined part of the plastic liner may be combined with each other by the thermal bonding.

The metallic nozzle boss may include: a flange part being combined with the wing part of the plastic sealing member so as to cover the wing part thereof, and a boss part extending along a longitudinal direction of the cylindrical part of the plastic sealing member from the flange part, wherein the boss part may include threads provided on an inner circumferential surface thereof so as to be engaged with a valve.

The flange part of the metallic nozzle boss may be provided to be longer than the wing part of the plastic sealing member so as to be combined with the wing part such that the flange part completely covers the wing part.

The cylindrical part of the plastic sealing member may be provided to extend up to the threads provided on the boss part of the metallic nozzle boss such that the cylindrical part and the threads are connected to each other.

The high-pressure vessel may further include the valve screwed to the boss part of the metallic nozzle boss by being inserted thereinto.

A front end of the valve may be provided to be inserted to an inner side of the cylindrical part of the plastic sealing member, and a front end part of the valve positioned on the inner side of the cylindrical part may include multiple valve O-rings combined thereon so as to maintain airtightness between the valve and the cylindrical part.

The plastic liner and the plastic sealing member may be combined with each other only by the thermal bonding without additionally including a fastening member and a rubber sealing member.

The present invention has a structure in which a gap does not occur between the plastic liner and the plastic sealing member due to the plastic sealing member being combined with the plastic liner by thermal bonding, thereby completely blocking the leakage of high-pressure gas to a gap between the plastic liner and the plastic sealing member.

In addition, as the plastic liner and the plastic sealing member made of the same materials are combined with each other by the thermal bonding, use of the conventional lower fastening member is unnecessary and further, use of a rubber sealing member for maintaining airtightness is unnecessary, whereby productivity enhancement via reduction in the number of components, a weight, a cost, and man-hours is promoted.

Hereinbelow, a high-pressure vessel for a vehicle for a vehicle according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in <FIG>, the high-pressure vessel for a vehicle according to the present invention includes: a plastic liner <NUM> including a through hole <NUM> provided thereon; a plastic sealing member <NUM>, a portion of which is positioned in the through hole <NUM> and a remaining portion of which overlaps with the plastic liner <NUM>, wherein the portion overlapping with the plastic liner <NUM> is combined with the plastic liner <NUM> by thermal bonding; a metallic nozzle boss <NUM> combined with the plastic sealing member <NUM> so as to cover the portion of the plastic sealing member <NUM> overlapping with the plastic liner <NUM>; a composite material layer <NUM> combined with the plastic liner <NUM> and the metallic nozzle boss <NUM> so as to cover the plastic liner and the metallic nozzle boss; and a valve <NUM> screwed to the metallic nozzle boss <NUM>.

For weight reduction, the plastic liner <NUM> is integrally manufactured of a plastic material such as high-density polyethylene, polypropylene, or polyester resin by blow molding.

A material of the plastic sealing member <NUM> is preferably the same material as a material of the plastic liner <NUM> and is manufactured by injection molding, and during the blow molding of the plastic liner <NUM>, the plastic sealing member <NUM> is combined with the plastic liner <NUM> by the thermal bonding.

When the plastic liner <NUM> and the plastic sealing member <NUM>, which are made of the same materials, are combined with each other by the thermal bonding, the plastic liner <NUM> and the plastic sealing member <NUM> are completely combined with each other so as not to prevent a gap therebetween. Accordingly, high-pressure gas can be completely prevented from leaking to the gap between the plastic liner <NUM> and the plastic sealing member <NUM>.

In addition, as the plastic liner <NUM> and the plastic sealing member <NUM>, which are made of the same materials, are combined with each other by the thermal bonding, use of a conventional lower fastening member <NUM> is unnecessary, and further, use of a rubber sealing member <NUM> for maintaining airtightness is unnecessary, whereby productivity enhancement via reduction in the number of components, a weight, a cost, and man-hours is promoted.

The metallic nozzle boss <NUM> is made of a metal, which is different from materials of the plastic liner <NUM> and the plastic sealing member <NUM>, so as to be securely combined with the valve <NUM> made of a metal.

As shown in <FIG>, the metallic nozzle boss <NUM> is screwed to the plastic sealing member <NUM> (M1), and in this case, a major portion of a lower surface of the metallic nozzle boss, which faces the plastic liner <NUM>, is in contact with the plastic sealing member <NUM> and only some portion thereof is in contact with the plastic liner <NUM>.

Though minute gaps may occur between the metallic nozzle boss <NUM> and the plastic liner <NUM>, which are made of different materials, and between the metallic nozzle boss <NUM> and the plastic sealing member <NUM>, which are made of different materials, the gaps do not directly communicate with an inner part of the high-pressure vessel.

That is, the gap between the metallic nozzle boss <NUM> and the plastic liner <NUM> and the gap between the metallic nozzle boss <NUM> and the plastic sealing member <NUM> communicate with the inner part of the high-pressure vessel only by a gap between the plastic liner <NUM> and the plastic sealing member <NUM>.

However, according to the embodiment of the present invention, the plastic liner <NUM> and the plastic sealing member <NUM>, which are made of the same materials, are completely combined with each other by the thermal bonding so as not to prevent the gap. Accordingly the gap between the metallic nozzle boss <NUM> and the plastic liner <NUM> and the gap between the metallic nozzle boss <NUM> and the plastic sealing member <NUM> are blocked by the plastic liner <NUM> and the plastic sealing member <NUM> combined with each other by the thermal bonding such that the gaps do not directly communicate with the inner part of the high-pressure vessel. Accordingly, the high-pressure gas stored in the high-pressure vessel is fundamentally prevented from leaking to the outside.

The composite material layer <NUM> made by mixing carbon fiber or glass fiber with polymer resin such as epoxy resin for strength maintenance is combined with the plastic liner <NUM> and the nozzle boss <NUM> so as to cover surfaces of the plastic liner <NUM> and the nozzle boss <NUM>.

The valve <NUM> manufactured of a metallic material is combined with the metallic nozzle boss <NUM> by being screwed thereto.

The plastic sealing member <NUM> includes a cylindrical part <NUM> positioned in the through hole <NUM> of the plastic liner <NUM> and protruding in an outer side direction of the plastic liner <NUM>; and a wing part <NUM> of a circular plate shape provided to bend so as to correspond a shape of the plastic liner <NUM> while extending in a radial direction from an end of the cylindrical part <NUM> and a predetermined section of which is combined with an outer surface of the plastic liner <NUM> by the thermal bonding.

The wing part <NUM> includes a curved part 22a formed curvedly so as to have a wavy shape, a horizontal part 22b extending in a horizontal direction, and an inclined part 22c provided on the horizontal part 22b to incline toward a protruding direction of the cylindrical part <NUM>.

The inclined part 22c of the wing part <NUM> is provided to have the same shape as an inclined part <NUM> of the plastic liner <NUM>, and the inclined part 22c and the inclined part <NUM> are combined with each other by the thermal bonding.

As mentioned before, the plastic liner <NUM> is blow molded and is combined with the plastic sealing member <NUM> by the thermal bonding during the blow molding. A combined portion of the plastic sealing member <NUM> with the plastic liner <NUM> by the thermal bonding is the wing part <NUM>, wherein the curved part 22a of the wing part <NUM> is weak in a combining force due to a curved shape thereof and the horizontal part 22b, which is weak in a support force, may be deformed by a pressure occurring during the thermal bonding. Accordingly, the inclined part 22c that is strong in a combining force and can sufficiently bear the pressure occurring during the thermal bonding is preferably combined with the inclined part <NUM> of the plastic liner <NUM> by the thermal bonding.

The metallic nozzle boss <NUM> includes a flange part <NUM> being combined with the wing part <NUM> of the plastic sealing member <NUM> so as to cover the wing part <NUM> thereof; and a boss part <NUM> extending along a longitudinal direction of the cylindrical part <NUM> of the plastic sealing member <NUM> from the flange part <NUM>, wherein the boss part <NUM> includes threads 32a provided on an inner circumferential surface thereof so as to be engaged with the valve <NUM> and accordingly, is engaged with threads <NUM> of the valve <NUM>.

The flange part <NUM> of the metallic nozzle boss <NUM> is provided to be longer than the wing part <NUM> of the plastic sealing member <NUM> so as to be combined with the wing part <NUM> such that the flange part completely covers the wing part. Accordingly, the wing part <NUM> of the plastic sealing member <NUM> is completely brought into close contact with the plastic liner <NUM> by an applying force of the flange part <NUM> of the metallic nozzle boss <NUM> so as to maintain a more stable combining force with the plastic liner and sufficiently bear a pressure of the high-pressure gas stored in the vessel.

A length of the flange part <NUM> is preferably configured to be roughly <NUM>% to <NUM>% longer than a length of the wing part <NUM>, but is not limited thereto.

The cylindrical part <NUM> of the plastic sealing member <NUM> is preferably provided to extend up to the threads 32a provided on the boss part <NUM> of the metallic nozzle boss <NUM> such that the cylindrical part <NUM> and the threads 32a are combined with each other.

That is, a gap between an end of the cylindrical part <NUM> and the threads 32a is removed so as to maintain a secure combining force of the plastic sealing member <NUM> and particularly, to prevent a gas leak at the maximum.

The valve <NUM> is inserted into the boss part <NUM> to be screwed to the boss part <NUM>. In this case, a front end of the valve <NUM> is provided to be inserted to an inner side of the cylindrical part <NUM> of the plastic sealing member <NUM>, and a front end part of the valve <NUM> positioned on the inner side of the cylindrical part <NUM> includes multiple valve O-rings <NUM> combined thereon so as to maintain airtightness between the valve and the cylindrical part <NUM>.

Each of the valve O-rings <NUM> is a rubber in a material thereof and prevents the high-pressure gas in the vessel from leaking through a gap between the cylindrical part <NUM> of the plastic sealing member <NUM> and the valve <NUM>. When durability of the valve O-ring decreases due to use thereof, only the valve O-ring <NUM> is required to be replaced with a new valve O-ring after separating the valve <NUM> from the boss part <NUM>.

According to the embodiment described above, the present has a structure in which a gap does not occur between the plastic liner <NUM> and the plastic sealing member <NUM> due to the plastic sealing member <NUM> being combined with the plastic liner <NUM> by thermal bonding, thereby completely blocking the leakage of high-pressure gas to a gap between the plastic liner <NUM> and the plastic sealing member <NUM>.

In addition, as the plastic liner <NUM> and the plastic sealing member <NUM> made of the same materials are combined with each other by the thermal bonding, use of the conventional lower fastening member <NUM> is unnecessary, and further, use of the rubber sealing member <NUM> for maintaining the airtightness is unnecessary, whereby the productivity enhancement via the reduction in the number of components, a weight, a cost, and man-hours is promoted.

Although the preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope of the invention as defined in the accompanying claims.

Claim 1:
A high-pressure vessel for a vehicle, the high-pressure vessel comprising:
a plastic liner (<NUM>) including a through hole (<NUM>) provided thereon;
a plastic sealing member (<NUM>), a portion of which is positioned in the through hole (<NUM>) and a remaining portion of which overlaps with the plastic liner (<NUM>),
wherein the portion overlapping with the plastic liner (<NUM>) is combined with the plastic liner (<NUM>) by thermal bonding;
a metallic nozzle boss (<NUM>) combined with the plastic sealing member (<NUM>) so as to cover the portion of the plastic sealing member (<NUM>) overlapping with the plastic liner (<NUM>); and
a composite material layer (<NUM>) combined with the plastic liner (<NUM>) and the metallic nozzle boss (<NUM>) so as to cover the plastic liner (<NUM>) and the metallic nozzle boss (<NUM>); the high-pressure vessel for a vehicle wherein
the plastic sealing member (<NUM>) includes
a cylindrical part (<NUM>) positioned in the through hole (<NUM>) of the plastic liner (<NUM>) and protruding in an outer side direction of the plastic liner (<NUM>), and
a wing part (<NUM>) of a circular plate shape provided to bend so as to correspond a shape of the plastic liner (<NUM>) while extending in a radial direction from an end of the cylindrical part and a predetermined section of which is combined with an outer surface of the plastic liner (<NUM>) by the thermal bonding;
wherein the metallic nozzle boss (<NUM>) is screwed to the plastic sealing member (<NUM>) (M1); and
characterised in that
a major portion of a lower surface of the metallic nozzle boss (<NUM>), which faces the plastic liner (<NUM>), is in contact with the plastic sealing member (<NUM>) and only some portion thereof is in contact with the plastic liner (<NUM>).