Pressure container with liner having holding groove and seal groove

A liner includes a covering portion that covers an inner surface over the entire circumference of the inner surface of a flange portion of a mouthpiece. A covering opposing portion, which is the inner surface of the flange portion and covered with the covering portion, includes a holding groove and a seal groove on the radially outer side of the flange portion. In an axial cross-section of a pressure container, the holding groove extends, from its groove opening toward groove bottom, in a direction inclined toward a radially inner side of the flange portion with respect to a boss portion axial direction, and the seal groove extends, from its groove opening toward groove bottom, in a direction different from the direction of the holding groove. The covering portion includes a holding rib fitted into the holding groove and movable therein, and a seal rib fitted into the seal groove.

BACKGROUND

1. Technical Field

The present invention relates to a pressure container for filling pressurized substances.

2. Related Art

For example, Japanese Unexamined Patent Publication No. 2000-291888 and Japanese Unexamined Patent Publication No. 2014-167346 disclose a pressure container for filling compressed gas such as hydrogen and compressed natural gas (CNG). Japanese Unexamined Patent Publication No. 2000-291888 discloses the pressure container in which a metal mouthpiece is integrally attached to an opening circumferential edge of a cylindrical resin liner, and a surface of the liner is covered with a reinforcing layer. The mouthpiece includes a boss portion having a cylindrical shape, and a flange portion which protrudes toward a radially outer side from the boss portion. According to Japanese Unexamined Patent Publication No. 2000-291888, an annular groove is provided at a bottom portion of the flange portion, and one part of the liner is fitted into the annular groove, thus enhancing sealability between the mouthpiece and the liner.

Meanwhile, Japanese Unexamined Patent Publication No. 2014-167346 discloses the pressure container in which a groove portion is provided at a bottom portion of a flange portion of a mouthpiece, an opening end of the liner, a collar member, and a seal member of an elastic body are disposed in the groove portion, and the opening end of the liner is sandwiched between a groove portion wall surface, the collar member, and the seal member, thus enhancing the sealability between the mouthpiece and the liner.

However, in Japanese Unexamined Patent Publication No. 2000-291888, one part of the liner is slidably disposed in the annular groove to alleviate stress concentration at the time of expansion or contraction of the liner. Since the one part of the liner moves within the annular groove, the sealability between the liner and the annular groove wall surface is insufficient.

In Japanese Unexamined Patent Publication No. 2014-167346, in the groove portion of the flange portion of the mouthpiece, the opening end of the liner is fixed to the groove portion by being sandwiched between the collar member and the seal member. The occurrence of stress concentration at the opening end of the liner by the expansion or contraction of the liner becomes a concern. Furthermore, since the collar member and the seal member need to be attached to the inside of the groove portion, the number of components increases and the attachment is troublesome.

SUMMARY

The present invention is made in view of the above circumstances, and an object thereof is to provide a pressure container in which the sealability between a mouthpiece and a liner is enhanced without increasing the number of components.

The present invention provides a pressure container including a mouthpiece including a boss portion which has a cylindrical shape and a flange portion which protrudes toward a radially outer side from the boss portion, and a liner which is made of resin and is integrated with the flange portion of the mouthpiece to define an internal space together with the mouthpiece. In the pressure container, the flange portion has an inner surface that faces the internal space, the liner includes a covering portion that covers at least one part of the inner surface over an entire circumference of the inner surface of the flange portion, a covering opposing portion, which is the inner surface of the flange portion and is covered with the covering portion, includes a holding groove and a seal groove provided on a radially outer side of the flange portion than on the holding groove, at an axial cross-section parallel to a center axis of the boss portion, the holding groove is provided to extend, from a groove opening toward a groove bottom, in a direction inclined toward a radially inner side of the flange portion with respect to an axial direction of the boss portion, and the seal groove is provided to extend, from the groove opening toward the groove bottom, in a direction different from a direction in which the holding groove extends, and the covering portion includes a holding rib fitted into the holding groove so as to be movable forward and backward within the holding groove, and a seal rib fitted into the seal groove.

According to the configuration described above, the pressure container can be provided in which the sealability between the mouthpiece and the liner is enhanced without increasing the number of components.

DETAILED DESCRIPTION

A pressure container according to an embodiment of the present invention will be described.

The pressure container of the present embodiment includes a mouthpiece made of metal, and a liner made of resin. The mouthpiece includes a boss portion which has a cylindrical shape, and a flange portion which protrudes toward a radially outer side from the boss portion.

The liner is integrated with the flange portion of the mouthpiece to define an internal space together with the mouthpiece. The liner integrally fixes the mouthpiece at an opening circumferential edge by insert molding. The flange portion has an inner surface that faces the internal space.

The liner includes a covering portion that covers at least one part of the inner surface over the entire circumference of the inner surface of the flange portion. A covering opposing portion, which is the inner surface of the flange portion and is covered with the covering portion, includes a holding groove and a seal groove provided on the radially outer side of the flange portion than on the holding groove.

At an axial cross-section of the boss portion, the holding groove is provided to extend, from a groove opening toward a groove bottom, in a direction inclined toward a radially inner side of the flange portion with respect to an axial direction parallel to a center axis of the boss portion. The seal groove is provided to extend, from the groove opening toward the groove bottom, in a direction different from a direction in which the holding groove extends.

The covering portion includes a holding rib fitted into the holding groove so as to be movable forward and backward within the holding groove, and a seal rib fitted into the seal groove.

A surface direction of the inner surface of the flange portion of the mouthpiece may be changed or may be constant at the covering opposing portion. For example, the inner surface of the flange portion may include, at the covering opposing portion, a bottom portion and a side portion provided on the radially outer side than on the bottom portion and having a surface direction different from that of the bottom portion.

The holding groove may be provided in the vicinity of an inner circumferential edge on the radially inner side of the covering opposing portion. In this case, when the inner pressure of the internal space is depressurized, the inner circumferential edge portion on the radially inner side of the covering portion of the liner is held, at the flange portion of the mouthpiece, by the holding rib fitted into the holding groove. The sealability between the mouthpiece and the liner can be ensured without the inner circumferential edge portion separating from the flange portion. When the inner surface of the flange portion of the mouthpiece includes the bottom portion and the side portion at the covering opposing portion, the holding groove and the seal groove may be provided in the bottom portion, or the holding groove and the seal groove may be provided in the side portion.

A direction from the groove opening toward the groove bottom with respect to the holding groove is referred to as a holding groove direction A, and a direction from the groove opening toward the groove bottom with respect to the seal groove is referred to as a seal groove direction B. The holding groove direction A is a direction inclined toward the radially inner side of the flange portion with respect to the axial direction of the boss portion. The seal groove direction B is a direction different from the holding groove direction A.

The holding groove and the seal groove may be provided in singular, or may be provided in plurals. When the plurality of holding grooves are provided, the holding groove directions A of the plurality of holding grooves have the same angle with respect to each other with respect to the radially inner side of the flange portion. In the present specification, when two or more grooves having different angles with respect to the radially inner side of the flange portion are provided at the covering opposing portion of the inner surface of the flange portion, a groove located on the most radially inner side at the covering opposing portion is referred to as a holding groove and a groove located on the radially outer side of the covering opposing portion than the holding groove is referred to as a seal groove.

When a plurality of seal grooves are provided on the inner surface of the flange portion, each seal groove direction B of the plurality of seal grooves may have the same angle with respect to each other, or may have different angles with respect to each other. Each of the seal groove direction B of the plurality of seal grooves merely needs to be a different direction with respect to the holding groove direction A of the holding groove.

By the holding groove direction A and the seal groove direction B being different directions from each other, the holding rib and the seal rib are brought into strong pressure contact at any region of the holding groove inner wall and the seal groove inner wall, and high sealability is exerted at the relevant region even when the liner expands or contracts due to the inner pressure, temperature, external force, and the like of the pressure container.

In the present embodiment and the following implementation examples, the axial direction parallel to the center axis of the boss portion coincides with a center axis of the pressure container, and an axial direction parallel to such center axes is hereinafter referred to as an axial direction.

In the present embodiment, an angle α1of the holding groove direction A of holding groove with respect to the axial direction preferably ranges from 10 to 80°, and most preferably ranges from 40 to 70°. When the angle α1is smaller than 10°, the holding rib is less likely to slide within the holding groove when the liner expands or contracts, and stress may concentrate at a base end in the vicinity of the groove opening of the holding groove in the holding rib. When the angle α1is greater than 80°, the holding groove becomes difficult to form. When the angle α1is smaller than or equal to 70°, the processing of the holding groove is more easily carried out, and when the angle α1is greater than or equal to 40°, the stress is less likely to concentrate at the base end of the holding rib.

The seal groove direction B of the seal groove is a direction different from the holding groove direction A of the holding groove. An angle β1of the seal groove direction B with respect to the axial direction may be smaller than or greater than the angle α1of the holding groove direction A with respect to the axial direction. A difference between the angle α1of the holding groove direction A with respect to the axial direction and the angle β1of the seal groove direction B with respect to the axial direction preferably ranges from 5 to 150°, and more preferably ranges from 10 to 130°.

At the axial cross-section of the pressure container, when a direction from an outer circumferential edge toward an inner circumferential edge at the covering opposing portion of the inner surface of the flange portion is assumed as a surface direction of the covering opposing portion, an angle β2of the seal groove direction B with respect to the surface direction of the covering opposing portion is preferably greater than an angle α2of the holding groove direction A with respect to the surface direction of the covering opposing portion. In this case, a surface pressure of the seal rib with respect to the seal groove inner wall becomes higher than a surface pressure of the holding rib with respect to the holding groove inner wall, and higher sealing performance can be exerted at the seal groove.

At the axial cross-section of the pressure container, the seal groove is provided to extend in a perpendicular direction with respect to the surface direction of the covering opposing portion or is provided to extend in a direction inclined toward the outer circumferential edge side of the covering opposing portion with respect to the perpendicular direction. Thus, at the time of contraction of the liner, an outer side portion of the seal rib, in particular, the base end of the outer side portion comes into strong pressure contact with the periphery of the groove opening of the seal groove, thus exerting high sealing performance.

The holding groove and the seal groove may be annular grooves formed to a ring shape continuing in the circumferential direction to the inner surface of the flange portion, or may be a plurality of holes or grooves disposed at intervals in the circumferential direction. The holding groove and the seal groove are preferably formed as annular grooves to enhance the sealability between the liner and the mouthpiece.

The holding groove has a shape that allows the holding rib to be slidable. The shape of the holding groove may be, for example, such that at the axial cross-section of the pressure container, a groove width is constant from the groove opening to the groove bottom or such that the groove width gradually becomes smaller from the groove opening to the groove bottom.

The shape of the holding rib is a shape that is slidable in the holding groove. The shape of the holding groove may be, for example, such that at the axial cross-section of the pressure container, a thickness is constant from the base end to the distal end or such that the thickness gradually becomes thinner from the base end toward the distal end.

The seal groove may have a shape that allows the seal rib to be slidable or a shape by which the seal rib is difficult to slide. The shape of the seal groove may be, for example, such that from the groove opening to the groove bottom at the axial cross-section of the pressure container, the groove width is constant or such that the groove width gradually becomes smaller, or a step-like portion may be formed on the inner wall.

The seal rib may have a shape that allows the seal rib to be slidable in the seal groove or a shape by which the seal rib is difficult to slide in the seal groove. The shape of the seal groove may be, for example, such that from the base end to the distal end at the axial cross-section of the pressure container, the thickness is constant or such that the thickness gradually becomes smaller. The seal rib may include a step-like portion.

The holding groove and the seal groove preferably have a depth such that the ribs will not come off even when the liner contracts and the holding rib and the seal rib are slid toward the groove opening. The depths of the holding groove and the seal groove preferably range from 5 to 10 mm.

The covering opposing portion of the inner surface of the flange portion of the mouthpiece may include a plurality of seal grooves. When the covering opposing portion includes two seal grooves, at the axial cross-section of the pressure container, the two seal grooves are preferably provided to extend from the groove opening toward the groove back in a direction of approaching each other. At the time of expansion or contraction of the liner, the seal ribs in the two seal grooves perform different movements from each other, and have high surface pressure at different regions in the seal grooves. The two seal ribs also exert strong anchor effect. Thus, the covering portion between the two seal grooves is less likely to move or is less likely to separate from the covering opposing portion. Thus, the sealing performance between the liner and the mouthpiece enhances at the covering opposing portion.

At the axial cross-section of the pressure container, the two seal grooves are preferably symmetric with each other with respect to a normal line of the covering opposing portion, and provided to extend in symmetrical directions with each other. The seal groove direction B of the two seal grooves is a direction different from the holding groove direction A. The two seal grooves are preferably provided to extend, from the groove opening toward the groove bottom, in a direction inclined so as to approach each other. In such a case, at the time of expansion or contraction of the liner, the seal ribs in the two seal grooves perform different movements from each other, and have high surface pressures at different regions in the seal groove. Since the two seal ribs exert strong anchor effect, the covering portion is less likely to move and is less likely to separate from the covering opposing portion. Thus, the covering portion can exert strong sealing performance.

An elastic coating film may be interposed between the covering opposing portion of the inner surface of the flange portion of the mouthpiece and the covering portion of the liner. The elastic coating film is, for example, made of rubber, and can be vulcanization-bonded to the covering opposing portion. When the inner pressure of the internal space is high, the covering portion is brought into pressure contact with the elastic coating film. Thus, the sealability between the covering portion and the covering opposing portion can be further enhanced.

The pressure container of the present embodiment can be used as a container for filling various pressurized substances represented by compressed gas such as hydrogen and compressed natural gas (CNG), and liquefied gas such as liquefied natural gas (LNG), and liquefied petroleum gas (LPG).

IMPLEMENTATION EXAMPLES

First Implementation Example

A pressure container according to a first implementation example of the present invention will be described.

As shown inFIG. 1, a pressure container1of the first implementation example includes a liner2made of resin, a mouthpiece5integrally fixed to an axial end of the liner2, and a reinforcing layer8that covers the liner2. The liner2and the mouthpiece5define an internal space7.

The liner2has a cylindrical shape (hollow shape). The liner2has, at both ends, openings20in the axial direction thereof. The openings20each have a diameter smaller than a diameter at a central portion of the liner2in the axial direction. The mouthpiece5and a mouthpiece6are integrally fixed to respective openings20. The mouthpiece5is provided for attachment of a piping valve, and the mouthpiece6is a sealing plug. A fixing structure of the mouthpiece5to the corresponding opening20of the liner2is the same as that of the mouthpiece6, and thus the mouthpiece5will be described below.

As shown inFIG. 2, the mouthpiece5is made of metal such as aluminum. The mouthpiece5includes a boss portion51having a cylindrical shape, and a flange portion52that protrudes radially from the boss portion51.

The mouthpiece5is integrated with the liner2at the flange portion52. The flange portion52has an inner surface53that faces the internal space7. The inner surface53of the flange portion52includes, for example, a bottom portion55located on a radially inner side, and a side portion56located on a radially outer side than on the bottom portion55. The bottom portion55is provided to circularly extend roughly along the radial direction of the pressure container1. The side portion56is provided to annularly extend in the axial direction of the pressure container1.

For example, a resin material excelling in gas barrier properties is used for the liner2. Specific examples of the material of the liner2include PPS (polyphenylene sulfide), EVOH (ethylene vinyl alcohol), polyethylene, polyamide, and the like.

The liner2integrally fixes the mouthpiece5at a circumferential edge of the corresponding opening20by insert molding. In order to fix the mouthpiece5to the liner2, the resin material is injected into a mold where the mouthpiece5is disposed to mold the liner2.

The liner2includes a covering portion21that covers one part of the inner surface53over the entire circumference of the inner surface53of the flange portion52of the mouthpiece5. The covering portion21continuously covers over the entire side portion56from the radially outer side portion of the bottom portion55of the flange portion52.

The front surface of the liner2is covered with the reinforcing layer8. The reinforcing layer8covers the entire outer surface of the liner2and an outer surface54of the flange portion52of the mouthpiece5. The reinforcing layer8includes a reinforcing fiber and an epoxy resin. The reinforcing fiber is wound around the outer surface of the liner2, impregnated with the epoxy resin, and subjected to heating and curing, thus forming the reinforcing layer8. Examples of the reinforcing fiber include carbon fiber, glass fiber, aramid fiber, and the like.

The inner surface53of the flange portion52includes a covering opposing portion57covered with the covering portion21of the liner2. The covering opposing portion57includes a holding groove32, and a seal groove33provided on a more radially outer side of the flange portion52than the holding groove32. A holding rib22projecting from the covering portion21of the liner2is fitted into the holding groove32. A seal rib23projecting from the covering portion21is fitted into the seal groove33.

The holding groove32is provided at the covering opposing portion57in the bottom portion55of the flange portion52. Two seal grooves33are provided at the covering opposing portion57in the side portion56of the flange portion52. When describing the two seal grooves33separately, out of the two seal grooves33, the seal groove33located on the inner circumferential edge side of the covering opposing portion57of the side portion56of the flange portion52is referred to as a first seal groove33a, and the seal groove33located on the outer circumferential edge side of the covering opposing portion57is referred to as a second seal groove33b.

The holding groove32is provided at the inner circumferential edge of the covering opposing portion57. Thus, when the inner pressure of the internal space7is depressurized, the sealability between the mouthpiece5and the liner2can be ensured without the inner circumferential edge of the covering portion21of the liner2floating up from the flange portion52.

As shown inFIGS. 3 and 4, a direction from the groove opening toward the groove bottom with respect to the holding groove32is a holding groove direction A, and a direction from the groove opening toward the groove bottom with respect to the seal groove33is a seal groove direction B. The holding groove direction A is a direction inclined toward the radially inner side of the flange portion52. The seal groove direction B is a direction different from the holding groove direction A.

Since the holding groove direction A and the seal groove direction B are different directions from each other, the holding rib22and the seal rib23are brought into strong contact with either region of the inner wall of the holding groove32and the inner wall of the seal groove33, thus exerting high sealability at the contacting portion even when the liner2expands or contracts due to the inner pressure, temperature, external force, and the like in the pressure container1.

As shown inFIG. 2, for example, when the liner2contracts as a result that the pressure container1is subjected to a temperature change, to an inner pressure change of the internal space7, or to an external force from an exterior of the pressure container1, the covering portion21attempts to contract and the stress in the covering portion21increases. The holding groove32is provided to extend, from the groove opening toward the groove bottom, in the direction inclined toward the radially inner side of the flange portion52with respect to the axial direction. As shown with a dotted line inFIGS. 2 and 3, the holding rib22slides in the holding groove32in a direction in which the holding rib22comes off the holding groove32, and alleviates the stress of the covering portion21. As shown with a dotted line inFIGS. 2 and 4, the seal rib23also attempts to move in the direction in which the seal rib23comes off the seal groove33in order to alleviate the stress of the covering portion21. The seal groove33is provided to extend in a direction different from the direction in which the holding groove32extends. Thus, the seal rib23in the seal groove33is forced to move in the direction different from the direction in which the holding rib22comes off the holding groove32. Then, the seal rib23is brought into pressure contact with the wall surface of the seal groove33thus causing distortion. As a result, the surface pressure of the seal rib23with respect to the inner wall of the seal groove33locally increases. In particular, the seal rib23makes a pressure contact with an outer side portion33cof the inner wall of the seal groove33, in particular, a base end33hof the groove opening of the outer side portion33c, and exerts high sealability between the seal rib23and the seal groove33.

When the liner2expands after the pressure container is subjected to the temperature change, the inner pressure change, or the external force, the covering portion21stretches along the inner surface53of the flange portion52of the mouthpiece5. The holding rib22advances toward the groove back side of the holding groove32and comes into pressure contact with the inner wall of the holding groove32. The seal rib23advances toward the groove back side of the seal groove33and comes into pressure contact with the inner wall of the seal groove33. Since the seal groove33is provided to extend in the direction different from the direction in which the holding groove32extends, the seal rib23has a high surface pressure at a portion different from a portion where the holding rib22has a high surface pressure. The seal rib23exerts the sealing performance different from that of the holding rib22with respect to the groove inner wall. The seal rib23can enhance the sealability between the liner2and the mouthpiece5while the seal rib23supplements it each other with the holding rib22.

When the inner pressure of the internal space7is high, the covering portion21of the liner2is brought into pressure contact with the covering opposing portion57of the mouthpiece5, so that high sealability is exerted between the covering portion21and the covering opposing portion57. When the inner pressure of the internal space7lowers, a force of being pulled toward the internal space7side acts on the covering portion21of the liner2, and the covering portion21attempts to separate from the covering opposing portion57. However, the holding rib22is fitted into the holding groove32. Thus, the covering portion21is suppressed from separating from the covering opposing portion57.

Thus, with the provision of the holding groove32and the seal groove33on the inner surface53of the flange portion52of the mouthpiece5, high sealability between the liner2and the mouthpiece5can be ensured when the liner2contracts or expands. Even when the pressure container1is subjected to the temperature change, the inner pressure change of the internal space7, or to the external force from the exterior of the pressure container1, the pressure container1can exert high sealability.

On the contrary, as shown inFIG. 5, when the holding groove direction A and the seal groove direction B are the same direction, the seal rib23slides in the same direction as the direction in which the holding rib22slides, as a result of the contraction of the covering portion21. The seal rib23merely generates the stress of the same extent as that of the holding rib22. The sealability between the seal rib23and the seal groove33becomes low to the same extent as the sealability between the holding rib22and the holding groove32.

In the first implementation example, an angle α1of the holding groove direction A of the holding groove32with respect to the axial direction is 60°, as shown inFIGS. 3 and 4. An angle β1of the seal groove direction B of the first seal groove33awith respect to the axial direction is 80°, whereas an angle β1of the seal groove direction B of the second seal groove33bwith respect to the axial direction is 100°.

At the axial cross-section of the pressure container1, a direction from the outer circumferential edge toward the inner circumferential edge at the covering opposing portion57of the inner surface53of the flange portion52is a surface direction of the covering opposing portion57. In the first implementation example, the surface direction of the covering opposing portion57is substantially parallel with the radially inner side of the flange portion52at the bottom portion55of the inner surface53of the flange portion52, and the surface direction of the covering opposing portion57is substantially parallel with the axial direction at the side portion56. In this case, the angle α2of the holding groove direction A of the holding groove32with respect to the surface direction of the covering opposing portion57is 30°, the angle β2of the seal groove direction B of the first seal groove33ais 80°, and the angle β2of the seal groove direction B of the seal groove33bis 100°.

At the axial cross-section of the pressure container1, the first seal groove33ais provided to extend in a direction inclined toward the outer circumferential edge side of the covering opposing portion57with respect to a direction perpendicular to the surface direction of the covering opposing portion57. Thus, an outer side portion23cof the seal rib23in the first seal groove33a, in particular, a base end23hof the outer side portion23ccomes into strong pressure contact with the periphery of the groove opening of the first seal groove33aat the time of the contraction of the liner2, thus exerting high sealability.

The holding groove32and the two seal grooves33are all annular grooves formed in a ring shape continuing in the circumferential direction to the inner surface53of the flange portion52.

The holding groove32has a shape that allows the holding rib22to be slidable. The holding groove32has a constant groove width of 3 mm from the groove opening to the groove bottom at the axial cross-section. The two seal grooves33each have a shape that allows the seal rib23to be slidable. The two seal grooves33each have a constant groove width of 2 mm from the groove opening to the groove bottom at the axial cross-section.

The holding groove32has a depth of 7 mm, and each of the two seal grooves33has a depth of 8 mm. Any of the grooves has a depth at which the holding rib22and the seal rib23do not come off the grooves, even when the liner2contracts and the holding rib22and the seal rib23are slid toward the groove opening side.

At the axial cross-section of the pressure container1, the first seal groove33aand the second seal groove33bare symmetric with each other with respect to the normal line of the side portion56, and are provided to extend in symmetrical directions with each other. The seal groove direction B of the first seal groove33aand the second seal groove33bis a direction different from the holding groove direction A. The first seal groove33aand the second seal groove33bare provided to extend in directions inclined so as to approach each other toward the groove bottom. Thus, at the time of the expansion or contraction of the liner2, the seal ribs23in the two seal grooves33perform different movements from each other, and the surface pressures of the seal ribs23become high at different regions of the seal grooves33. Since the two seal ribs23exert strong anchor effect, the covering portion21between the two seal grooves33is less likely to move or is less likely to separate from the covering opposing portion57. Thus, the covering portion21can exert strong sealing performance.

In the first implementation example, the covering opposing portion57of the flange portion52of the mouthpiece5includes the two seal grooves33, but may include one seal groove33.

The liner2includes an outer covering portion29that covers the outer circumferential edge of the outer surface54of the flange portion52. The outer covering portion29is integrally connected to an end of the covering portion21. The outer covering portion29covers the flange portion52over the entire circumferential direction, as in the covering portion21. The radially outer side of the flange portion52is covered with the covering portion21and the outer covering portion29of the liner2, and strongly integrally fixed to the liner2. When the liner2contracts, the outer covering portion29also contracts and attempts to separate from the outer surface54of the liner2. A dotted line ofFIG. 2shows a state in which the outer covering portion29separates from the outer surface54. Even when the outer covering portion29separates from the outer surface54and thus a gap is formed between the outer covering portion29and the outer surface54of the flange portion52, the seal rib23(in particular, base end23hon the outer covering portion29side of the seal rib23) locally comes into strong pressure contact with the inner wall of the seal groove33. Thus, the sealability between the mouthpiece5and the liner2can be reliably ensured.

An elastic coating film may be interposed between the covering opposing portion57of the inner surface53of the flange portion52of the mouthpiece5and the covering portion21of the liner2. The elastic coating film is, for example, made of rubber, and can be vulcanization-bonded to the covering opposing portion57. When the inner pressure of the internal space7is high, the covering portion21is brought into pressure contact with the elastic coating film. Thus, the sealability between the covering portion21and the covering opposing portion57can be further enhanced.

Second Implementation Example

As shown inFIG. 6, at an axial cross-section of a pressure container1according to a second implementation example, the pressure container1has a side portion56of a flange portion52of a liner2provided to extend in a direction inclined toward the radially outer side at an angle γ of 50° with respect to an axial direction. One of two seal grooves33, a first seal groove33a, is provided to extend in the axial direction, and a second seal groove33bis provided to extend parallel to the radially inner side.

The angle α1of the holding groove direction A of the holding groove32with respect to the axial direction is 60° The angle β1of the seal groove direction B of the first seal groove33awith respect to the axial direction is 0°, and the angle β1of the seal groove direction B of the second seal groove33bwith respect to the axial direction is 90° (seeFIGS. 3 and 4).

The angle α2of the holding groove direction A of the holding groove32with respect to the surface direction of the covering opposing portion57is 30°, the angle β2of the seal groove direction B of the first seal groove33ais 130°, and the angle β2of the seal groove direction B of the second seal groove33bis 40° (seeFIGS. 3 and 4).

The seal rib23in the first seal groove33aand the seal rib23in the second seal groove33bhave different surface pressure distributions at the time of expansion or contraction of the liner2, each exert different sealing performances, and complement each other. Thus, when the pressure container1is subjected to the temperature change, the inner pressure change, or the external force change, high sealability is exerted in either case.

In the second implementation example as well, at the axial cross-section of the pressure container1, the two seal grooves33are provided to extend in a direction of gradually approaching each other toward the groove bottom. Thus, strong sealing performance can be exerted between the two seal grooves33.

The covering portion21of the liner2covers the side portion56from the outer circumferential edge of the bottom portion55of the flange portion52of the mouthpiece5. The inner circumferential edge of the covering portion21is located on the outer circumferential edge of the bottom portion55. The holding groove32is provided in the vicinity of the outer circumferential edge of the bottom portion55. The holding rib22projecting out from the inner circumferential edge of the covering portion21is fitted into the holding groove32in a manner movable forward and backward.

In the second implementation example, at the axial cross-section of the pressure container1, the length from the inner circumferential edge to the outer circumferential edge of the covering portion21covering the inner surface53of the flange portion52of the mouthpiece5is shorter than the length from the inner circumferential edge to the outer circumferential edge of the covering portion21of the first implementation example. In the pressure container1of the second implementation example, a leakage route of the pressurized substances in the internal space7is formed between the inner circumferential edge and the outer circumferential edge of the covering portion21, where the leakage route of the second implementation example is shorter than the leakage route of the first implementation example. In the second implementation example, however, the holding groove32and the two seal grooves33are provided in the covering opposing portion57. Thus, the sealability between the covering portion21and the covering opposing portion57is sufficiently ensured. The pressure container1of the second implementation example can exert excellent sealability.

Third Implementation Example

As shown inFIG. 7, a pressure container1of a third implementation example differs from the second implementation example in that three seal grooves33are provided to extend parallel to each other at an axial cross-section of the pressure container1.

At the axial cross-section of the pressure container1, the three seal grooves33are provided to extend parallel to each other, and are all provided to extend, from the groove opening toward the groove bottom, in a direction inclined toward the radially inner side with respect to the axial direction. Furthermore, at the axial cross-section of the pressure container1, when a direction from the outer circumferential edge toward the inner circumferential edge at the covering opposing portion57of the inner surface53of the flange portion52is assumed as a surface direction of the covering opposing portion57, the angles β2of the seal groove direction B of the three seal grooves33with respect to the surface direction of the covering opposing portion57are all 90°. In the third implementation example, the angle γ with respect to the axial direction of the side portion56of the flange portion52of the mouthpiece5is 50°, as in the second implementation example, and thus the angles β1of the seal groove direction B of the three seal grooves33with respect to the axial direction are all 40°.

In the third implementation example as well, the angle α1of the holding groove direction A of the holding groove32with respect to the axial direction is 60°, as in the second implementation example. The angle α2of the holding groove direction A of the holding groove32with respect to the surface direction of the covering opposing portion57is 30° (seeFIG. 3).

When the liner2expands, the covering portion21is moved toward the inner circumferential edge side in the surface direction of the covering opposing portion57, and the seal ribs23in the three seal grooves33are brought into pressure contact with inner side portions33eof the inner walls of the seal grooves33. When the liner2contracts, the covering portion21is moved toward the outer circumferential edge side in the surface direction of the covering opposing portion57, and the seal ribs23are brought into pressure contact with outer side portions33cof the inner walls of the seal grooves33. The inner side portions33eand the outer side portions33care provided to extend in a direction of substantially 90° with respect to the surface direction of the covering opposing portion57, and thus even when the covering portion21is moved toward the inner circumferential edge side or moved toward the outer circumferential edge side in the surface direction, the seal ribs23can be brought into pressure contact with the inner walls of the seal grooves33at the surface pressures of the same extent in either case. Thus, the high sealing performance in the seal grooves33can be ensured at the same level at the time of expansion and at the time of contraction of the liner2.

Fourth Implementation Example

As shown inFIG. 8, a pressure container1of a fourth implementation example differs from the second implementation example in that a rib step-like portion23dis provided on the seal rib23.

In the fourth implementation example, one holding groove32and one seal groove33are provided on the covering opposing portion57of the inner surface53of the flange portion52of the mouthpiece5. The holding groove32of the fourth implementation example is provided to extend in the same direction as the direction in which the holding groove32of the second implementation example extends, and the seal groove33of the fourth implementation example is provided to extend in the same direction as the direction in which the first seal groove33aof the second implementation example extends. In other words, the angle α1of the holding groove direction A of the holding groove32with respect to the axial direction is 60°, and the angle β1of the seal groove direction B of the seal groove33is 0°. In the fourth implementation example as well, the angle γ with respect to the axial direction of the side portion56of the flange portion52of the mouthpiece5is 50°, as in the second implementation example, and hence the angle α2of the holding groove direction A of the holding groove32with respect to the surface direction of the covering opposing portion57is 30°, and the angle β2of the seal groove direction B of the seal groove33with respect to the surface direction of the covering opposing portion57is 130° (seeFIGS. 3 and 4). The length from the groove opening to the groove bottom of the seal groove33is 8 mm, and is longer than the length (7 mm) from the groove opening to the groove bottom of the holding groove32. The groove width of the seal groove33is greater than the groove width of the holding groove32.

A groove step-like portion33dis provided on the inner wall of the seal groove33. The groove step-like portion33dis provided near the center portion between the groove opening and the groove bottom of the outer side portion33cof the seal groove33. The groove step-like portion33dis formed such that the diameter increases from the groove back side toward the groove opening. The seal rib23having a shape that corresponds to the inner wall of the seal groove33is fitted into the seal groove33. The rib step-like portion23dcorresponding to the groove step-like portion33dof the seal groove33is provided on the outer side portion23cof the seal rib23. The rib step-like portion23dis brought into pressure contact with the groove step-like portion33d, and exerts high sealing performance. In particular, the seal rib23attempts to move toward the radially outer side at the time of contraction of the liner2, and the outer side portion23cof the seal rib23comes into pressure contact with the outer side portion33cof the inner wall of the seal groove33. The outer side portion23cof the seal rib23has a higher surface pressure with respect to the outer side portion33cof the seal groove33at the rib step-like portion23d, and exerts excellent sealing performance.

In the fourth implementation example, the rib step-like portion23dis provided on the outer side portion23cof the seal rib23, but the rib step-like portion may be provided on the inner side portion23eof the seal rib23. A groove step-like portion may also be provided on the holding groove32as long as the holding rib22is slidable.

(1) According to the implementation examples, a pressure container includes a mouthpiece including a boss portion which has a cylindrical shape and a flange portion which protrudes toward a radially outer side from the boss portion; and a liner which is made of resin and is integrated with the flange portion of the mouthpiece to define an internal space together with the mouthpiece, in which the flange portion has an inner surface that faces the internal space, the liner includes a covering portion that covers at least one part of the inner surface over an entire circumference of the inner surface of the flange portion, a covering opposing portion, which is the inner surface of the flange portion and is covered with the covering portion, includes a holding groove, and a seal groove provided on a radially outer side of the flange portion than on the holding groove, at an axial cross-section parallel to a center axis of the pressure container, the holding groove is provided to extend, from a groove opening toward a groove bottom, in a direction inclined toward a radially inner side of the flange portion with respect to an axial direction of the boss portion, and the seal groove is provided to extend, from the groove opening toward the groove bottom, in a direction different from a direction in which the holding groove extends, and the covering portion includes a holding rib fitted into the holding groove so as to be movable forward and backward in the holding groove, and a seal rib fitted into the seal groove.

According to the configuration described above, in the inner surface of the flange portion of the mouthpiece, the holding groove and the seal groove are provided at the covering opposing portion covered with the covering portion of the liner. For example, when the pressure container is subjected to the temperature change, to the inner pressure change of the internal space, or to the external force from the exterior of the pressure container, the liner contracts or expands.

When the liner contracts, the covering portion attempts to contract and stress generates at the covering portion. The holding groove is provided to extend, from the groove opening toward the groove bottom, in a radially inner side of the flange portion, and the holding rib is fitted into the holding groove so as to be movable forward and backward. The holding rib slides in the holding groove in a direction in which the holding rib comes off the holding groove, thus alleviating the stress of the covering portion. The seal rib attempts to move in a direction in which the seal rib comes off the seal groove in order to alleviate the stress of the covering portion. The seal groove is provided to extend in a direction different from the direction in which the holding groove extends. Thus, the seal rib in the seal groove is forced to move in the direction different from the direction in which the holding rib comes off the holding groove. The surface pressure of the seal rib with respect to the inner wall of the seal groove locally increases, and the sealability between the liner and the mouthpiece can be ensured.

When the liner expands, the covering portion expands and stretches along the covering opposing portion of the mouthpiece. The holding rib slides toward the groove back side of the holding groove and comes into pressure contact with the inner wall of the holding groove. The seal rib advances toward the groove back side of the seal groove and comes into pressure contact with the inner wall of the seal groove. Since the seal groove is provided to extend in a direction different from the direction in which the holding groove extends, the seal rib has a high surface pressure at a portion different from a portion where the holding rib has a high surface pressure, and exerts sealing performance different from that of the holding rib with respect to the groove inner wall. The seal rib can enhance the sealability between the liner and the mouthpiece while the seal rib supplements it each other with the holding rib.

Furthermore, when the inner pressure of the internal space is high, the covering portion of the liner is brought into pressure contact with the covering opposing portion of the mouthpiece, so that high sealability is exerted between the covering portion and the covering opposing portion. When the inner pressure of the internal space lowers, a force of being pulled toward the internal space acts on the covering portion of the liner, and the covering portion attempts to separate from the covering opposing portion. In the present embodiment, the holding rib is fitted into the holding groove. Thus, the covering portion is suppressed from separating from the covering opposing portion.

Thus, with the provision of the holding groove and the seal groove on the inner surface of the flange portion of the mouthpiece, high sealability between the liner and the mouthpiece can be ensured when the liner contracts or expands. Even when the pressure container is subjected to the temperature change, to the inner pressure change of the internal space, or to the external force from the exterior of the pressure container, the pressure container1can exert high sealability.

According to the configuration described above, the pressure container can be provided in which the sealability between the mouthpiece and the liner is enhanced without increasing the number of components.

(2) In (1), the inner surface of the flange portion of the mouthpiece preferably includes, at the covering opposing portion, a bottom portion, and a side portion located on a radially outer side of the flange portion than on the bottom portion and extending in a direction intersecting the bottom portion, and the bottom portion preferably includes the holding groove, and the side portion preferably includes the seal groove.

According to the configuration of (2), when the inner pressure of the internal space is depressurized, the covering portion is less likely to separate from the flange portion and the sealability of the pressure container can be ensured. Furthermore, the covering portion can be effectively suppressed from separating from the side portion in the seal groove.

(3) In (1) or (2), at the axial cross-section of the pressure container, the seal groove is preferably provided to extend in a perpendicular direction with respect to the covering opposing portion or provided to extend in a direction inclined toward an outer circumferential edge side of the covering opposing portion with respect to the perpendicular direction.

According to the configuration of (3), an outer side portion of the seal rib, in particular, a base end of the outer side portion of the seal rib comes into a strong pressure contact with the periphery of a groove opening of the seal groove at the time of contraction of the liner, thus exerting high sealing performance.

(4) In any one of (1) to (3), the covering opposing portion preferably includes a plurality of seal grooves.

According to the configuration of (4), the contacting area of the inner wall of the seal groove and the seal rib increases by the number of seal grooves, thus exerting high sealing performance.

(5) In (4), the covering opposing portion preferably includes two seal grooves, and at the axial cross-section of the pressure container, the two seal grooves are preferably directed in a direction of approaching each other from the groove opening toward the groove back.

According to the configuration of (5), the seal ribs in the two seal grooves perform different movements from each other and come into pressure contact with different regions in the seal groove when the liner expands or contracts. Furthermore, since the two seal ribs exert strong anchor effect, the portion of the covering portion between the two seal grooves is less likely to move and is less likely to separate from the covering opposing portion. Thus, the strong sealing performance can be exerted between the two seal grooves.

The two seal grooves specified in (5) are preferably provided on the side portion of the inner surface of the flange portion of the mouthpiece specified in (2). In such a case, when the liner is subjected to the temperature change, to the inner pressure change, or to the external force, the covering portion of the liner can be effectively prevented from separating from the side portion side of the flange portion by the anchor effect of the seal groove.

(6) In any one of (1) to (5), the seal rib preferably includes a step-like portion.

According to the configuration of (6), at the step-like portion, the contacting area of the seal rib and the inner wall of the seal groove increases, thus exerting excellent sealing performance.