JP2024019920A - Method for manufacturing high-pressure tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a high-pressure tank in which a matrix resin is impregnated to acquire stable strength while suppressing looseness of a reinforcement fiber that is wound around a boundary part.

SOLUTION: A method for manufacturing a high-pressure tank includes the steps of: preparing a liner that includes a liner body 11A continuing to a barrel part 14 in which a storage space S is formed and including a neck part 15 extending toward an opening 13 and a metal reinforcement body 40 disposed in the neck part 15, as a liner 11; forming a reinforcement fiber base material 12A at an outer peripheral surface 11a of the liner 11 by winding a reinforcement fiber 12a around the outer peripheral surface of the liner 11; and disposing the liner 11 around which the reinforcement fiber base material 12A is wound in a shaping mold 93 and injecting a matrix resin 11B between the shaping mold 93 and the liner 11 while applying internal pressure to the storage space S to impregnate the matrix resin 11B into the reinforcement fiber base material 12A and form a reinforcement layer 12.

SELECTED DRAWING: Figure 7

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a method of manufacturing a high pressure tank.

For example, high-pressure tanks for storing fuel gas are used in natural gas vehicles, fuel cell vehicles, and the like. This type of high-pressure tank includes a liner that accommodates fluid, which is high-pressure gas, and a reinforcing layer made of fiber-reinforced resin that covers the outer peripheral surface of the liner.

When manufacturing a high-pressure tank, first a resin liner is prepared. The liner has a body portion in which a storage space for containing high-pressure gas is formed, and a neck portion formed continuously at an end of the body portion. A reinforcing layer made of fiber-reinforced resin is formed on the outer peripheral surfaces of the body and neck of the prepared liner (for example, see Patent Document 1).

JP2020-60265A

Here, for example, when forming the reinforcing layer shown in Patent Document 1, a reinforcing fiber base material is formed on the outer peripheral surface of the liner by winding reinforcing fibers around the outer peripheral surface of the liner, and then the reinforcing fiber base material is It is envisaged that it will be impregnated with a matrix resin.

In this case, a liner around which a reinforcing fiber base material is wound is placed in a mold, and a matrix resin is injected between the mold and the liner while applying internal pressure to the housing space of the liner. At this time, hoop stress acts on the body of the liner so as to expand in the circumferential direction of the body, so that the reinforcing fibers wound around the body of the liner are unlikely to be misaligned.

However, since the boundary portion between the body portion and the neck portion has a concave shape, hoop stress acts on the boundary portion so as to reduce it in the circumferential direction due to the shape. Due to this hoop stress, the diameter of the boundary portion is slightly reduced, and the reinforcing fibers wound around the boundary portion tend to loosen. Even if reinforcing fibers (reinforcing fiber base material) are impregnated with matrix resin in this state, it is difficult to ensure mechanical strength at the boundary portion.

The present invention was made in view of these points, and provides a high-pressure tank that can obtain stable strength by impregnating matrix resin with the reinforcing fibers wound around the boundary portions suppressing the slack. A manufacturing method is provided.

In view of the above-mentioned problems, the method for manufacturing a high-pressure tank according to the present invention includes: a resin liner in which a storage space for accommodating a fluid is formed and an opening formed in at least one end side; and a resin liner that covers the outer circumferential surface of the liner. a reinforcing layer made of fiber-reinforced resin, the method comprising: as the liner, a neck portion that is continuous with the body portion in which the accommodation space is formed and extends toward the opening portion; a step of preparing a liner including a liner body having a liner body and a metal reinforcing body disposed at least at a boundary portion between the neck portion and the body portion; and winding reinforcing fibers around the outer peripheral surface of the liner. The step of forming a reinforcing fiber base material on the outer peripheral surface of the liner, placing the liner around which the reinforcing fiber base material is wound in a mold, and applying internal pressure to the accommodation space with the mold. The method is characterized by including a step of impregnating the reinforcing fiber base material with the matrix resin and forming the reinforcing layer by injecting the matrix resin between the reinforcing fiber base material and the liner.

According to the present invention, when forming the reinforcing layer, when internal pressure is applied to the accommodation space in which the liner is formed, the boundary between the neck part of the liner and the body part has a concave shape. Hoop stress acts on the hoop so that it shrinks in the circumferential direction. However, in the present invention, since the metal reinforcing body is disposed at least at the boundary portion, deformation of the boundary portion in the circumferential direction can be suppressed. Thereby, the matrix resin can be impregnated into the reinforcing fiber base material while suppressing the slack of the reinforcing fibers wound around the boundary portion. As a result, a high pressure tank with stable strength can be obtained.

In a more preferred embodiment, the reinforcing body is integrally molded with the liner main body in the step of preparing the liner.

According to this aspect, since the reinforcing body is integrally molded with the liner body, the liner body is restrained by the reinforcing body. Therefore, even if hoop stress acts on the boundary portion so as to reduce it in the circumferential direction, the shape of the boundary portion can be maintained.

In a more preferred embodiment, the high-pressure tank is provided with a connecting member that covers the opening, and the connecting member is formed with an insertion portion that is inserted into the opening, and the insertion portion includes a connecting member that covers the opening. , a sealing member that contacts the inner circumferential surface of the liner is attached, and the reinforcing body extends to a position facing the sealing member.

According to this aspect, since the reinforcing body is extended to a position facing the sealing member, even if fluid is filled and discharged into the accommodation space when the high-pressure tank is used, the reinforcing body will ensure that the sealing by the sealing member is maintained. can be ensured.

According to the present invention, stable strength can be obtained by impregnating the matrix resin into the reinforcing fiber base material while suppressing the slack of the reinforcing fibers wound around the boundary portion.

FIG. 1 is a perspective view showing the structure of a tank unit including a high-pressure tank manufactured by the manufacturing method according to the present embodiment. FIG. 2 is a cross-sectional view of the high-pressure tank taken along line AA in FIG. 1; FIG. 3 is an enlarged sectional view of a main part of the high-pressure tank on the bracket side shown in FIG. 2; FIG. 4 is a cross-sectional view for explaining a step of preparing a liner in the method of manufacturing the high-pressure tank shown in FIG. 3. FIG. FIG. 2 is a diagram for explaining a step of forming a reinforcing fiber base material in the method for manufacturing the high-pressure tank shown in FIG. 1. FIG. FIG. 4 is a diagram for explaining a state in which a reinforcing fiber base material is formed in the method for manufacturing the high-pressure tank shown in FIG. 3. FIG. FIG. 2 is a cross-sectional view for explaining a step of forming a reinforcing layer in the method of manufacturing the high-pressure tank shown in FIG. 1. FIG. FIG. 3 is a diagram for explaining hoop stress that acts when forming a reinforcing layer in the method for manufacturing a high-pressure tank according to the present embodiment.

1. Regarding the high-pressure tank 10 First, an embodiment of the tank unit 1 including the high-pressure tank 10 will be described below with reference to FIGS. 1 to 3. As shown in FIGS. 1 and 2, the tank unit 1 according to the present embodiment includes a plurality of high-pressure tanks 10 and a pair of connecting members 30, 30 connected to both ends of the high-pressure tanks 10.

The high-pressure tank 10 is a tank loaded with high-pressure hydrogen gas that is mounted on a fuel cell vehicle. The gases that can be filled into the high-pressure tank 10 are not limited to high-pressure hydrogen gas, but also various compressed gases such as CNG (compressed natural gas), and various liquefied gases such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas). , or other gases (fluids), or may be temporarily filled with a fluid such as a liquid for a pressure test.

The high-pressure tank 10 includes a liner 11 in which a storage space S for storing hydrogen gas is formed and openings 13 formed on both sides, and a reinforcing layer 12 laminated on the liner 11 so as to cover the outer peripheral surface 11a of the liner 11. It is equipped with. The liner 11 includes a liner body 11A made of a resin material having gas barrier properties and a reinforcing body 40 made of metal. The reinforcing layer 12 is made of fiber reinforced resin.

The liner main body 11A includes a body part 14 in which the above-described accommodation space S is formed, and a pair of neck parts 15, 15 that are continuous with the ends of the body part 14 and have an opening 13 formed therein. In this embodiment, the neck portions 15 are formed on both sides of the liner 11, but the high-pressure tank 10 may have a bottle-like structure in which the neck portion 15 is formed only on one side.

In this embodiment, the body part 14 includes a cylindrical body 14a, which is an example of a cylindrical shape, and a shoulder part 14b whose inner diameter and outer diameter decrease as the body progresses from the body 14a toward the end of the body part 14. ing. The shoulder portion 14b is a cylindrical portion in the shape of a truncated cone, and a neck portion 15 is formed so as to be continuous with the shoulder portion 14b. The neck portion 15 is a cylindrical portion, and extends toward the opening 13 in a direction along the axis CL of the high-pressure tank 10. Therefore, the boundary portion 16 between the body portion 14 (shoulder portion 14b) and the neck portion 15 has an apparently concave shape.

In this embodiment, a metal reinforcing body 40 is disposed at the boundary portion 16 between the neck portion 15 and the body portion 14 . The reinforcing body 40 may extend to a part of the neck portion 15 in order to ensure sealing performance, which will be described later.

In this embodiment, an annular base 20 is attached to the outer peripheral surface 12b of the reinforcing layer 12 that covers the neck portion 15. A plurality of protrusions are formed on the inner circumferential surface 22 of the cap 20, and the reinforcing layer 12 is formed to bite into the inner circumferential surface 22 (specifically, to bite between the protrusions). Thereby, the cap 20 can be locked to the reinforcing layer 12. A male thread is formed on the outer circumferential surface 21 of the cap 20, and this male thread can be screwed into a female thread on an inner wall surface 34 formed on a connecting member 30, which will be described later.

Here, in this embodiment, the resin constituting the liner main body 11A is preferably a resin with good gas barrier properties. Such resins include polypropylene resins, nylon resins (for example, 6-nylon resins or 6,6-nylon resins), polycarbonate resins, acrylic resins, ABS resins, polyamide resins, polyethylene resins, and ethylene resins. - Thermoplastic resins such as vinyl alcohol copolymer resins (EVOH) and polyester resins can be mentioned.

The reinforcing layer 12 is made of reinforcing fibers (reinforcing fiber base material) impregnated with a thermoplastic resin or thermosetting resin as a matrix resin. In this embodiment, the reinforcing fibers are fiber bundles. As the reinforcing fibers, reinforcing fibers such as glass fibers, aramid fibers, boron fibers, and carbon fibers can be used, and it is particularly preferable to use carbon fibers from the viewpoints of lightness and mechanical strength. The matrix resin is preferably a thermosetting resin, and the thermosetting resin is a phenol resin, a melamine resin, a urea resin, or an epoxy resin. It is preferable to use The epoxy resin has fluidity in an uncured state, and becomes an epoxy resin that forms a strong crosslinked structure after thermosetting.

The reinforcing layer 12 is formed by winding reinforcing fibers (reinforcing fiber bundles) impregnated with matrix resin around the outer peripheral surface 11a of the liner 11 by a filament winding method or a sheet winding method. The reinforcing layer 12 may be a layer of helical winding in which the fiber bundle is wound so as to be inclined with respect to the axis CL of the high pressure tank 10; for example, the fiber bundle is wound with respect to the axis CL of the high pressure tank 10. It may be a layer woven in a diagonal manner (brader winding), or a combination of these layers may be laminated.

The pair of connecting members 30, 30 are members made of metal such as aluminum or steel, and are composed of a bracket 30A and a manifold 30B. The bracket 30A is a member for integrally restraining the plurality of high pressure tanks 10, 10, . . . and attaching it to the vehicle.

The manifold 30B is a member in which a gas flow path for introducing hydrogen gas into the accommodation space S of the high-pressure tank 10 and discharging hydrogen gas from the accommodation space S is formed. As shown in FIG. 2, the bracket 30A and the manifold 30B differ mainly in the presence or absence of a gas flow path, so the structure of the manifold 30B as the connection member 30 will be described with reference to FIG. 3.

The manifold 30B is formed to cover the opening 13 formed at the end of the high-pressure tank 10 in the direction of the axis CL, and includes an insertion portion 31 and a cap portion 32. The cap portion 32 is a portion of the outer peripheral surface 21 of the cap portion 20 that is screwed onto the cap portion 20 and covers the end surface of the high-pressure tank 10. The insertion portion 31 is formed in the center of the cap portion 32.

The insertion portion 31 is a plug-shaped portion that is inserted into the neck portion 15 from the opening 13 along the inner circumferential surface 15a of the neck portion 15. An annular groove 35 is formed along the circumferential direction of the outer peripheral surface 31a of the insertion portion 31, and annular seal members 61 and 62 for sealing the accommodation space S are arranged in the annular groove 35. There is. Specifically, the seal members 61 and 62 are in contact with the inner circumferential surface 11b of the liner 11 (specifically, the inner circumferential surface 15a of the neck portion 15), and in order to ensure sealing performance within the accommodation space S. , is in contact with the inner circumferential surface 11b while being slightly elastically deformed in the radial direction. The seal members 61 and 62 are made of an elastic material such as a resin material or a rubber material having gas barrier properties.

In this embodiment, the reinforcing body 40 has a cylindrical shape, and the inner circumferential surface 15a of the neck portion 15 is a member that limits deformation in the radial direction. The reinforcing body 40 is arranged at the boundary portion 16 between the neck portion 15 and the body portion 14 of the liner main body 11A. The reinforcing body 40 restrains deformation of at least the boundary portion 16 in the radial direction, and is formed so as to go around the outer circumferential surface 15d of the neck portion 15. In this embodiment, the reinforcing body 40 is integrally molded with the liner main body 11A.

Furthermore, in this embodiment, the reinforcing body 40 extends to a position facing the seal members 61 and 62 so as to go around the outer circumferential surface 15d of the liner 11. Since the reinforcing body 40 is extended to a position facing the sealing members 61 and 62, even if fluid is filled and discharged into the storage space S when the high-pressure tank 10 is used, the reinforcing body 40 prevents the sealing members 61 and 62 can ensure sealing performance.

The material of the reinforcing body 40 is a metal material such as stainless steel or aluminum, and if the inner circumferential surface 15a of the neck portion 15 can limit the deformation that spreads in the radial direction, the material is particularly limited. It is not something that will be done.

Here, "radial deformation of the inner circumferential surface 15a of the neck portion 15" refers to deformation when hoop stress is generated in the neck portion 15 due to the pressure of hydrogen gas. (More specifically, the portion of the liner 11 that contacts the seal members 61 and 62) is deformed to expand in the radial direction.

Further, the inner circumferential surface (opposing surface) of the reinforcing body 40 is in contact with the outer circumferential surface 15d of the neck portion 15. In this embodiment, the reinforcing body 40 extends from the end surface of the high-pressure tank 10 to a part of the shoulder portion 14b of the body portion 14. Of both ends of the reinforcing body 40, the end on the opening 13 side has a shape that expands in the radial direction of the reinforcing body 40, and the end on the body part 14 side is formed along the shape of the boundary portion 16. ing. This makes it easier for the reinforcing body 40 to engage with the reinforcing layer 12, and it is possible to prevent the reinforcing body 40 from slipping out in the direction along the axis CL.

2. Regarding the manufacturing method of the high-pressure tank The method of manufacturing the high-pressure tank 10 of this embodiment will be described below with reference to FIGS. 4 to 8.

(Process of preparing liner 11)
First, as shown in FIG. 4, a liner 11 including a liner main body 11A made of resin and a reinforcing body 40 made of metal is prepared. In this embodiment, the reinforcing body 40 is placed in an injection molding machine (not shown), and the liner main body 11A is integrally molded together with the reinforcing body 40. When molding with the liner body 11A, the liner body 11A is divided into two parts at a dividing plane perpendicular to the axis CL and located at the center of the liner body 11A, and then these are joined to form the liner body. The main body 11A may also be manufactured. Alternatively, the liner main body 11A may be disposed at the boundary portion 16 between the neck portion 15 and the body portion 14 after being molded.

(Step of forming reinforcing fiber base material)
As shown in FIGS. 5 and 6, a reinforcing fiber base material 12A is formed on the outer circumferential surface 11a of the liner 11 by winding the reinforcing fibers 12a around the outer circumferential surface 11a of the liner 11. Thereby, the preform 10A is formed. Continuous reinforcing fibers 12a are sequentially paid out from a plurality of bobbins 82, 82 of a braider (braiding machine) 80, and the reinforcing fibers 12a are braided and wound around the outer peripheral surface of one neck portion 15, and A reinforcing fiber base material 12A is formed from the portion 15 to the body portion 14 and the neck portion 15 on the other side. This method may be repeated to form the reinforcing fiber base material 12A, or helical winding and braiding winding may be used in combination to form the reinforcing fiber base material 12A, or only helical winding may be used to form the reinforcing fiber base material 12A. may be formed.

(Step of forming reinforcing layer 12)
As described above, the preform 10A (FIGS. 6 and 7) in which the reinforcing fiber base material 12A is formed on the hollow liner 11 is placed inside the mold 93 (between the lower mold 93A and the upper mold 93B, and also in the cavity). ). Next, the reinforcing layer 12 is molded using RTM impregnation technology.

Specifically, while applying internal pressure with gas to the housing space S of the liner 11 through a gas supply pipe 95 buried in the mold 93, the air pressure between the mold 93 and the liner 11 (specifically, inside the cavity) is increased. Then, by injecting the matrix resin 11B, the reinforcing fiber base material 12A is impregnated with the matrix resin 11B, thereby forming the reinforcing layer 12.

Here, when the matrix resin 11B is a thermosetting resin, after the matrix resin 11B is impregnated, the impregnated matrix resin may be thermoset at a heating temperature equal to or higher than the curing start temperature. Alternatively, the mold 93 may be heated in advance at a heating temperature equal to or higher than the curing start temperature, and the matrix resin may be thermally cured at the same time as the impregnation. On the other hand, when the matrix resin 11B is a thermoplastic resin, the matrix resin 11B may be impregnated with the matrix resin 11B while being heated above its softening point, and then cooled and solidified.

Note that when injecting the matrix resin 11B between the mold 93 and the liner 11 (specifically, inside the cavity), a resin injection pipe (also referred to as a resin injection gate) 92 to which a resin injection machine 91 is connected is used. The matrix resin 11B is injected through the injector. At the same time, air between the mold 93 and the liner 11 (specifically, inside the cavity) is degassed via a vacuum deaeration pipe 97 to which a vacuum pump 98 is connected.

By the way, when the matrix resin 11B is injected between the mold 93 and the liner 11 while applying internal pressure to the accommodation space S of the liner 11, the following phenomenon occurs. Specifically, as shown in part A in FIG. The rolled reinforcing fibers are unlikely to be misaligned.

However, as shown in part B of FIG. 8, the boundary portion 16 between the body portion 14 and the neck portion 15 has a concave shape, and due to this shape, the hoop shrinks in the circumferential direction of the boundary portion 16. A stress T acts. Due to this hoop stress T, the diameter of the boundary portion 16 is slightly reduced, and the reinforcing fibers 12a of the reinforcing fiber base material 12A wound around the boundary portion 16 are likely to loosen. In particular, when degassing is performed using the vacuum pump 98, this phenomenon becomes even more noticeable. In this state, even if the reinforcing fiber base material 12A is impregnated with the matrix resin 11B, it is difficult to ensure the mechanical strength of the boundary portion 16.

Therefore, in this embodiment, since the metal reinforcing body 40 is disposed at the boundary portion 16 between the neck portion 15 and the body portion 14 of the liner 11, deformation of the boundary portion 16 in the circumferential direction can be suppressed. Thereby, the reinforcing fiber base material 12A can be impregnated with the matrix resin 11B while suppressing the slack of the reinforcing fibers wound around the boundary portion 16. As a result, a high-pressure tank 10 with stable strength can be obtained.

In particular, in this embodiment, since the reinforcing body 40 is integrally molded with the liner body 11A, the liner body 11A is restrained by the reinforcing body 40. Therefore, even if the hoop stress T acts on the boundary portion 16 so as to reduce it in the circumferential direction, the shape of the boundary portion 16 can be maintained.

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

10: High pressure tank, 11: Liner, 11A: Liner main body, 11B: Matrix resin, 12: Reinforcement layer, 12A: Reinforced fiber base material, 14: Body part, 15: Neck part, 16: Boundary part, 30: Connection member , 31: Insertion part, 40: Reinforcement body, 93: Molding mold, S: Accommodation space

Claims (3)

A method for manufacturing a high-pressure tank having a resin liner in which a storage space for containing a fluid is formed and an opening formed in at least one end, and a reinforcing layer made of fiber-reinforced resin that covers the outer peripheral surface of the liner. And,
The liner includes a liner main body having a neck part continuous with the body part in which the housing space is formed and extending toward the opening, and a liner body disposed at least at a boundary part between the neck part and the body part. providing a liner with a metal reinforcement;
forming a reinforcing fiber base material on the outer peripheral surface of the liner by winding reinforcing fibers around the outer peripheral surface of the liner;
The liner around which the reinforcing fiber base material is wound is placed in a mold, and while applying internal pressure to the accommodation space, a matrix resin is injected between the mold and the liner, so that the reinforcing fibers are injected between the mold and the liner. A method for manufacturing a high-pressure tank, comprising the steps of impregnating a base material with the matrix resin and forming the reinforcing layer. 2. The method of manufacturing a high-pressure tank according to claim 1, wherein in the step of preparing the liner, the reinforcing body is integrally molded with the liner body. The high pressure tank is attached with a connecting member that covers the opening,
The connecting member is formed with an insertion portion that is inserted into the opening,
A sealing member that contacts the inner circumferential surface of the liner is attached to the insertion portion,
2. The method of manufacturing a high-pressure tank according to claim 1, wherein the reinforcing body extends to a position facing the sealing member.

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