Pressure vessel and method for manufacturing pressure vessel

Abstract

A pressure vessel according to the present invention comprises a hollow liner (2) having a pair of protruding portions (23A), (23B) that protrude in directions moving away from one other, a pair of mouthpieces (4A), (4B) that are connected to the pair of protruding portions (23A), (23B) by means of a fastening structure that involves rotation, and a fiber-reinforced resin layer (3) obtained by winding fibers around the outer peripheral surfaces of the liner (2) and the mouthpieces (4A), (4B). The pressure vessel is characterized in that the fastening directions in the connections between the pair of protruding portions (23A), (23B) and the mouthpieces (4A), (4B) are set to the directions in which the respective mouthpieces (4A), (4B) are fastened to the pair of protruding portions (23A), (23B) when the fibers are wound around the outer surface of the liner (2).

Description

Pressure vessel and method of manufacturing the pressure vessel

[0001] The present invention relates to a pressure vessel and a method for manufacturing a pressure vessel.

[0002] A pressure vessel is known that includes a liner having a barrel that contains a gas or liquid and a pair of protrusions that protrude outward from the barrel, a metal nozzle provided on the outer periphery of the protrusions, and a fiber-reinforced resin layer that covers the liner and the nozzle (Patent Document 1). For example, when forming the fiber-reinforced resin layer by filament winding, a drive shaft fitted to the nozzle is rotated to rotate the nozzle and liner together, and the fiber-reinforced resin is wound around the outer periphery of the liner.

[0003] JP 2009-58111 A JP 2017-122464 A

[0004] Some conventional pressure vessels use a screw-type structure to connect a pair of protrusions and a nozzle, as described in Patent Document 1. The threads in such a screw-type structure are all right-handed (or all left-handed). Therefore, for example, when unidirectional tension acts on the fiber during filament winding, one of the pair of protrusions moves in a direction that tightens the nozzle, while the other moves in a direction that loosens the nozzle. This causes a problem that the other nozzle rotates in the loosening direction relative to the liner during filament winding, making it difficult to securely assemble the nozzle. Also, as described in Patent Document 2, there is a method of preventing relative rotation of the nozzle with respect to the liner by providing a rotation restriction portion, such as a recess or protrusion, on the nozzle. However, when the nozzle structure becomes complicated, problems arise such as a tendency for molding defects to occur and increased production costs.

[0005] The present invention has been devised from this perspective, and has as its object to provide a pressure vessel and a method for manufacturing a pressure vessel that prevents the mouthpiece from rotating relative to the liner during manufacturing.

[0006] In order to solve the above problem, the present invention comprises a hollow liner having a pair of protrusions that protrude away from each other, a pair of nozzles that are connected to the pair of protrusions by a fastening structure that involves rotation, and a fiber-reinforced resin layer formed by winding fiber around the outer peripheral surfaces of the liner and the nozzle, and is characterized in that the fastening direction in connecting the pair of protrusions to the nozzle is set in the direction in which each of the nozzles is fastened to the pair of protrusions when the fiber is wound around the outer surface of the liner.

[0007] The present invention also provides a method for manufacturing a pressure vessel having a hollow liner having a pair of protrusions that protrude away from each other, and a pair of nozzles that are connected to the pair of protrusions by a fastening structure that involves rotation, the method comprising: a fastening step of fastening each of the nozzles to the pair of protrusions, and a fiber-reinforced resin layer forming step of rotating the liner and winding fiber around the outer peripheral surface of the liner to form a fiber-reinforced resin layer, wherein in the fiber-reinforced resin layer forming step, a drive shaft is fitted into the pair of nozzles, and the drive shaft and the nozzles are rotated synchronously to wind the fiber around the outer surface of the liner, and the nozzles and the protrusions are formed so that each of the nozzles is fastened to the pair of protrusions.

[0008] According to the present invention, the nozzle can be prevented from rotating relative to the liner during manufacturing without providing the liner or nozzle with a special shape.

[0009] Furthermore, it is preferable that the fastening structure between the pair of protrusions and the nozzle has a screw structure, and is formed so that the fastening direction in the screw connection between one of the protrusions and the nozzle is opposite to the fastening direction in the screw connection between the other protrusion and the nozzle.

[0010] According to the present invention, the nozzle can be prevented from rotating relative to the liner with a simple configuration.

[0011] According to the pressure vessel and the method for manufacturing a pressure vessel of the present invention, it is possible to prevent the mouthpiece from rotating relative to the liner during manufacturing.

[0012] Fig. 4 is a side cross-sectional view showing a pressure vessel according to an embodiment of the present invention. Fig. 5 is an enlarged side cross-sectional view showing the joining structure between a liner on one side and a nozzle. Fig. 6 is a side view showing the threading direction of the fastening structure of Fig. 2. Fig. 7 is an enlarged side cross-sectional view showing the joining structure between a liner on the other side and a nozzle. Fig. 8 is a side view showing the threading direction of the fastening structure of Fig. 4. Fig. 9 is a diagram showing the state of winding fibers around the outer periphery of the liner. Fig. 10 is a comparison table showing the action and effect of the pressure vessel according to the present embodiment.

[0013] <Pressure vessel according to embodiment> Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated description will be omitted as appropriate.

[0014] As shown in Fig. 1, the pressure vessel 1 according to this embodiment is used as a vessel for storing low-pressure gas such as LPG, high-pressure gas such as hydrogen gas, or other fluids. As shown in Fig. 1, the pressure vessel 1 of the present invention comprises a liner 2, a fiber-reinforced resin layer 3, and nozzles 4A and 4B.

[0015] The liner 2 includes a cylindrical body 21, dome portions 22, 22 formed on both ends of the body 21, and protrusions 23A, 23B protruding in directions away from the dome portions 22, 22. The liner 2 is made of a resin material such as high-density polyethylene (HDPE), polyamide, polyketone, or polyphenylene sulfide (PPS), and is formed by injection molding, blow molding, or the like.

[0016] The dome portions 22, 22 are formed continuously from both ends of the body portion 21, and the diameter decreases toward the ends. The dome portions 22, 22 are formed with protruding portions 23A, 23B that protrude outward and have a generally cylindrical shape. The protruding portions 23A, 23B are portions to which the nozzles 4A, 4B are connected, respectively. The connection structure between the protruding portions 23A, 23B and the nozzles 4A, 4B will be described in detail later.

[0017] The fiber reinforced resin layer 3 is made of, for example, FRP (fiber reinforced plastic) and serves to reinforce the pressure resistance strength of the liner 2. The fiber reinforced resin layer 3 is formed on the outer surfaces of the liner 2 and the mouthpieces 4A, 4B by, for example, using a filament winding method in which a fiber bundle impregnated with resin is wound and then the resin is cured.

[0018] The nozzles 4A, 4B are members fitted onto the protruding portions 23A, 23B of the liner 2 and are used to inject and discharge gas. The nozzles 4A, 4B are formed using a metal material such as a high-strength aluminum alloy or stainless steel alloy, and a valve or the like is inserted and attached to the nozzles 4A, 4B. In a fiber-reinforced resin layer forming step described below, a drive shaft V (see FIG. 6 ) is inserted into the nozzles 4A, 4B, and the liner 2 is rotated around the drive shaft V to wind the fibers, thereby forming the fiber-reinforced resin layer 3.

[0019] As shown in FIG. 2, the base 4A includes a tubular portion 44 and a flange portion 45. The tubular portion 44 is cylindrical and rises from the flange portion 45. The flange portion 45 is a portion that protrudes in a plate-like shape in the circumferential direction. The flange portion 45 is disposed in a recess 24 formed in the dome portion 22. The outer surface of the flange portion 45 and the outer surface of the dome portion 22 are flush with each other. As shown in FIG. 4, the base 4B includes a tubular portion 44 and a flange portion 45. The base 4B is identical to the base 4A except for the female thread formed on the inner circumferential surface.

[0020] (Fastening Structure) Next, the fastening structure between the liner 2 and the nozzles 4A, 4B will be described. First, the nozzle 4A will be described. As shown in FIG. 3 , a male thread (right-handed thread) S1 is formed on the outer peripheral surface of the protrusion 23A. That is, the threads are wound clockwise from the tip (top of the drawing) of the protrusion 23A to the base end (bottom of the drawing). On the other hand, a female thread (right-handed thread) S2 is formed on the inner peripheral surface of the nozzle 4A. That is, the thread grooves are wound clockwise from the tip (top of the drawing) of the nozzle 4A to the base end (bottom of the drawing). The protrusion 23A and the nozzle 4A are threadedly engaged to form a fastening structure 43. Note that, although the fastening structure 43 is a screw connection in this embodiment, any structure involving rotation may be used, such as a cam lock type.

[0021] As shown in FIG. 5 , a male thread (left-handed thread) S3 is formed on the outer peripheral surface of the protrusion 23B. That is, the threads are wound counterclockwise from the tip (top of the drawing) of the protrusion 23B to the base (bottom of the drawing). Meanwhile, a female thread (left-handed thread) S4 is formed on the inner peripheral surface of the base 4B. That is, the thread grooves are wound counterclockwise from the tip (top of the drawing) of the base 4B to the base (bottom of the drawing). The protrusion 23B and the base 4B are threadedly engaged to form a fastening structure 48. Note that, although the fastening structure 48 is a threaded connection in this embodiment, any structure involving rotation, such as a cam lock, may be used.

[0022] <<Method of Manufacturing Pressure Container According to Embodiment>> Next, a description will be given of a method of manufacturing the pressure container 1. In the method of manufacturing the pressure container according to this embodiment, a preparation step, a fastening step, and a fiber reinforced resin layer forming step are performed.

[0023] In the preparation process, the liner 2 and the nozzles 4A and 4B having the protrusions 23A and 23B are formed. The liner 2 is molded using a mold, for example, by blow molding. As described above, a male thread (right-handed thread) S1 is formed on the outer peripheral surface of the protrusion 23A, and a male thread (left-handed thread) S3 is formed on the outer peripheral surface of the protrusion 23B. As described above, a female thread (right-handed thread) S2 is formed on the inner peripheral surface of the nozzle 4A, and a female thread (left-handed thread) S4 is formed on the inner peripheral surface of the nozzle 4B.

[0024] In the fastening step, the base 4A is fastened to the protruding portion 23A by screwing, and the base 4B is fastened to the protruding portion 23B by screwing.

[0025] In the fiber-reinforced resin layer forming step, the fiber-reinforced resin layer 3 is formed using a filament winding method in which resin-impregnated fibers Z are wound around the outer peripheries of the liner 2 and the spindles 4A and 4B, as shown in Fig. 6. In this embodiment, as shown in Fig. 7, a drive shaft V extending from a motor (rotation drive unit) is inserted (fitted) into the inner surfaces of the spindles 4A and 4B, and the drive shaft V is rotated clockwise as viewed from the motor, causing the drive shaft V and the spindles 4A and 4B to rotate synchronously, and the liner 2 also rotates accordingly. The fibers Z are wound around the outer surface of the liner 2 while the liner 2 is rotated clockwise around the drive shaft V.

[0026] The method for manufacturing a pressure vessel liner is not limited to the above-described method. For example, although blow molding is used as an example of molding the liner 2, other molding methods such as rotational molding and injection molding may also be used.

[0027] (Functions and Effects) Here, Figure 7 is a comparison table showing the functions and effects of the pressure vessel according to this embodiment. As shown in Figure 7, before the countermeasures were implemented, the nozzle 104A was fastened to one of the protrusions 123A with a right-handed thread, and the nozzle 104B was fastened to the other protrusion 123B with a right-handed thread. Therefore, when the drive shaft V is rotated, tension from the wound fibers (see arrow C in Figure 7) is applied to the liner 2, restricting the rotation of the liner 2 relative to the rotation of the drive shaft V and the nozzles 104A and 104B. Therefore, the nozzle 104A on the upper side of the figure acts in a tightening direction, while the nozzle 104B on the lower side of the figure acts in a loosening direction. In other words, the nozzle 104B on the lower side of the figure loosens during filament winding, making it difficult to securely assemble the nozzle 104A.

[0028] In contrast, in this embodiment, the nozzle 4A is fastened to one of the protrusions 23A with a right-handed screw, and the nozzle 4B is fastened to the other protrusion 23B with a left-handed screw. As a result, when the drive shaft V is rotated, tension from the wound fibers (arrow C in Figures 6 and 7) is applied to the liner 2, which suppresses rotation of the liner 2 relative to the rotation of the drive shaft V and the nozzles 4A and 4B, and therefore both nozzles 4A and 4B act in a tightening direction. As a result, the liner 2 and the nozzles 4A and 4B can be firmly assembled with the fiber-reinforced resin layer 3.

[0029] According to the pressure vessel 1 of this embodiment described above, the fastening directions of the nozzles 4A, 4B and the protrusions 23A, 23B are set in the direction in which they tighten during filament winding. This prevents the nozzles 4A, 4B from rotating relative to the liner 2 during filament winding without requiring any special shapes for the liner 2 or the nozzles 4A, 4B.

[0030] The fastening structure 43 has a thread structure in which the male thread S1 of the protrusion 23A is threadedly engaged with the female thread S2 of the base 4A. The fastening structure 48 has a thread structure in which the male thread S3 of the protrusion 23B is threadedly engaged with the female thread S4 of the base 4B. This allows the fastening structure to be easily configured.

[0031] Although the embodiment of the present invention has been described above, appropriate design changes are possible within the scope of the present invention. For example, in this embodiment, the nozzle 4A is formed with a right-handed thread and the nozzle 4B is formed with a left-handed thread, but if the rotation direction of the liner 2 is reversed (counterclockwise) when viewed from the motor side, the nozzle 4A may be formed with a left-handed thread and the nozzle 4B with a right-handed thread.

[0032] REFERENCE SIGNS LIST 1 Pressure vessel 2 Liner 3 Fiber reinforced resin layer 4A, 4B Mouthpiece 21 Body 23A, 23B Protruding portion

Claims

1. A pressure vessel comprising: a hollow liner having a pair of protrusions protruding away from each other; a pair of nozzles connected to the pair of protrusions by a fastening structure involving rotation; and a fiber-reinforced resin layer formed by winding fiber around the outer peripheral surfaces of the liner and the nozzle, wherein the fastening direction in which the pair of protrusions are connected to the nozzles is set in the direction in which each of the nozzles is fastened to the pair of protrusions when the fiber is wound around the outer peripheral surface of the liner.

2. The pressure vessel according to claim 1, characterized in that the fastening structure between the pair of protrusions and the base has a screw structure, and is formed so that the fastening direction in the screw connection between one of the protrusions and the base is opposite to the fastening direction in the screw connection between the other protrusion and the base.

3. A method for manufacturing a pressure vessel having a hollow liner having a pair of protrusions protruding away from each other, and a pair of nozzles connected to the pair of protrusions by a fastening structure involving rotation, comprising: a fastening process for fastening each of the nozzles to the pair of protrusions, respectively; and a fiber reinforced resin layer forming process for rotating the liner and winding fiber around the outer peripheral surface of the liner to form a fiber reinforced resin layer, wherein in the fiber reinforced resin layer forming process, a drive shaft is engaged with the pair of nozzles while rotating the drive shaft and the nozzle synchronously to wind the fiber around the outer peripheral surface of the liner, and the nozzles and the protrusions are formed so that each of the nozzles is fastened to the pair of protrusions.

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