Pressure vessel and method for manufacturing pressure vessel

Abstract

The present invention is characterized by comprising: a liner (2) that is provided with a cylindrical trunk section (21), a head section (23) in which a mouthpiece (3) is disposed, and a shoulder section (22) that is provided between the trunk section (21) and the head section (23) and decreases in diameter toward the head section (23); and a reinforcing layer (4) that is formed on the outer peripheral surface of the liner (2) by winding fibers impregnated with a resin, wherein a groove section (25) is formed in at least one among a first boundary section (24) serving as a boundary between the head section (23) and the shoulder section (22) and a second boundary section (26) serving as a boundary between the trunk section (21) and the shoulder section (22), and resin that has seeped out from the reinforcing layer (4) has entered the groove section (25).

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 hollow liner and a reinforcing layer formed by winding resin-impregnated fibers around the outer surface of the liner (Patent Document 1). The liner includes a cylindrical body, a head where a nozzle is disposed, and a shoulder portion disposed between the body and the head, the diameter of which decreases toward the head. The reinforcing layer is formed by filament winding, in which a fiber-reinforced resin consisting of a bundle of resin-impregnated fibers is wound around the outer surface of the liner.

[0003] JP 2012-246962 A

[0004] The shoulder of the liner is tapered toward the head, which can lead to a problem of misalignment of the fiber-reinforced resin, particularly from the boundary between the body and shoulder to the head.

[0005] The present invention has been devised from this perspective, and an object of the present invention is to provide a pressure vessel and a method for manufacturing a pressure vessel that can prevent the fiber reinforced resin from shifting from a predetermined position.

[0006] The present invention is characterized in that it comprises a liner having a cylindrical body, a head on which a nozzle is disposed, and a shoulder provided between the body and the head and tapering in diameter toward the head, and a reinforcing layer formed by winding resin-impregnated fibers around the outer surface of the liner, wherein a groove is formed in at least one of a first boundary between the head and the shoulder and a second boundary between the body and the shoulder, and resin that has seeped out from the reinforcing layer enters the groove.

[0007] The present invention is also characterized by including a liner forming step of forming a liner having a cylindrical body, a head on which a nozzle is disposed, and a shoulder provided between the body and the head and tapering in diameter toward the head; a groove forming step of forming a groove in at least one of a first boundary between the head and the shoulder and a second boundary between the body and the shoulder; a reinforcing layer forming step of forming a reinforcing layer by winding resin-impregnated fibers around the outer peripheral surface of the liner; and a resin impregnation step of allowing the impregnated resin to enter the groove.

[0008] According to the present invention, the resin seeping out of the reinforcing layer enters the groove and hardens, thereby fixing the reinforcing layer to the liner, thereby preventing displacement of the fiber-reinforced resin with a simple structure.

[0009] In addition, it is preferable that the first boundary portion has a thick portion or a protruding portion that is thicker than other portions, and the groove portion is formed in the thick portion or the protruding portion. According to the present invention, it is possible to prevent the fiber-reinforced resin from shifting in position and to prevent a decrease in the strength of the pressure vessel.

[0010] According to the pressure vessel of the present invention, it is possible to provide a pressure vessel and a method for manufacturing a pressure vessel that can prevent the fiber reinforced resin from shifting from a predetermined position.

[0011] FIG. 1 is a side cross-sectional view showing a pressure vessel according to a first embodiment of the present invention. FIG. 2 is an enlarged side cross-sectional view showing the periphery of the nozzle of the first embodiment. FIG. 3 is an enlarged side cross-sectional view showing the periphery of the groove of the first embodiment. FIG. 4 is an enlarged side cross-sectional view showing a first modified groove of the first embodiment. FIG. 5 is an enlarged side cross-sectional view showing a second modified groove of the first embodiment. FIG. 6 is an enlarged side cross-sectional view showing a third modified groove of the first embodiment. FIG. 7 is an enlarged side cross-sectional view showing a fourth modified groove of the first embodiment. FIG. 8 is an enlarged side cross-sectional view showing a fifth modified groove of the first embodiment. FIG. 9 is an enlarged side cross-sectional view showing a sixth modified groove of the first embodiment. FIG. 10 is an enlarged side cross-sectional view showing a pressure vessel according to a second embodiment of the present invention. FIG. 11 is an enlarged side cross-sectional view showing a first modified groove of the second embodiment. FIG. 12 is an enlarged side cross-sectional view showing a second modified groove of the second embodiment. FIG. 13 is an enlarged side cross-sectional view showing a third modified groove of the second embodiment.

[0012] <Pressure vessel according to a first 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 explanations will be omitted as appropriate. Each embodiment and modified example can be combined as appropriate.

[0013] As shown in Fig. 1, the pressure vessel 1 according to this embodiment is used as a vessel for storing low-pressure gases such as LPG, high-pressure gases such as hydrogen gas, and other fluids. The pressure vessel 1 comprises a liner 2, a mouthpiece 3, and a reinforcing layer 4.

[0014] The liner 2 is made of a resin material such as high density polyethylene (HDPE), polyamide, polyketone, polyphenylene sulfide (PPS), or the like, and is formed by injection molding, blow molding, or the like. The liner 2 may be formed integrally, or may be formed separately and then joined together.

[0015] As shown in Figures 2 and 3, the liner 2 includes a body portion 21, a shoulder portion 22, and a head portion 23. The liner 2 is formed with approximately the same thickness except for a protrusion portion 27, which will be described later. The body portion 21 has a hollow cylindrical shape. The shoulder portion 22 is formed continuously from the end of the body portion 21 and gradually reduces in diameter toward the head portion 23. The shoulder portion 22 has a hemispherical dome shape. The head portion 23 is formed continuously from the end of the shoulder portion 22 and is the portion where the nozzle 3 is disposed. The head portion 23 includes a base portion 23a and a tubular portion 23b. The base portion 23a is perpendicular to the central axis O of the liner 2 and is flat. The tubular portion 23b rises from the base portion 23a and extends outward along the central axis O.

[0016] The boundary between the head portion 23 and the shoulder portion 22 is defined as a first boundary portion 24. When viewed in side cross section, the first boundary portion 24 is the portion that begins to curve from the end of the base portion 23 a toward the shoulder portion 22. Furthermore, the boundary portion between the shoulder portion 22 and the body portion 21 is defined as a second boundary portion 26. When viewed in side cross section, the second boundary portion 26 is the portion that begins to curve from the body portion 21 toward the shoulder portion 22. In other words, the first boundary portion 24 and the second boundary portion 26 are portions where the curvature changes significantly in the side cross-sectional shape of the liner 2.

[0017] As shown in Figures 2 and 3, the first boundary portion 24 has a protrusion 27 formed therein in the entire circumferential direction, the protrusion 27 being thicker than the other portions. When viewed in side cross section, the protrusion 27 protrudes from the base portion 23a in a generally mountain-like shape. The shape of the protrusion 27 is not particularly limited, as long as it is formed to be thicker (thick portion) than the other portions. In other words, it is preferable to set the thickness of the protrusion to a level that does not affect the strength of the liner 2 when a groove portion 25, which will be described later, is provided. The protrusion 27 may also be formed intermittently in the circumferential direction.

[0018] As shown in Figure 3, a groove 25 is formed at or near the top of the protrusion 27, concave toward the trunk portion 21 and parallel to the central axis O. Before the reinforcing layer forming process described below is performed, the groove 25 is open to the outside. Here, the groove 25 is formed so that resin exuding from the wound fiber-reinforced resin by the filament winding method can enter the groove 25. In other words, it is preferable to set the groove width of the groove 25 to a level that allows only the resin to enter and not the fibers to enter. Furthermore, it is preferable to set the depth of the groove 25 to a level that generates an anchor effect by the resin that has entered the groove 25, while taking into consideration the strength of the liner 2.

[0019] The nozzle 3 is a metal member disposed on the head 23 formed on the liner 2. The nozzle 3 comprises a flange portion 3a and a cylindrical portion 3b. The flange portion 3a is disk-shaped and disposed on the base portion 23a of the head 23. The cylindrical portion 3b rises from the flange portion 3a and extends outward along the central axis O. The cylindrical portion 3b and the cylindrical portion 23b are disposed in communication with each other, and are the portions through which the fluid stored in the pressure vessel 1 flows in and out. The nozzle 3 is disposed on the head 23 with almost no gaps between them.

[0020] 3, the outer peripheral surface (front surface) 3c of the flange portion 3a, the outer peripheral surface 22a of the shoulder portion 22, and the outer peripheral surface 27a of the protrusion 27 are arranged substantially flush with each other so as to avoid any steps. The protrusion 27 also has an inner peripheral surface 27b formed along the circumferential direction. This creates a recess where the inner peripheral surface 27b and the surface of the base 23a meet, allowing the flange portion 3a of the nozzle 3 to be positioned in the recess. The outer peripheral surface 27a of the protrusion 27 refers to the inclined surface of the protrusion 27 that faces outward relative to the central axis O. The inner peripheral surface 27b of the protrusion 27 refers to the inclined surface of the protrusion 27 that faces inward relative to the central axis O.

[0021] The reinforcing layer 4 is formed by winding a fiber-reinforced resin consisting of a bundle of resin-impregnated fibers around the outer surfaces of the liner 2 and the mouthpiece 3 by a filament winding method. The resin impregnated into the reinforcing fibers is not particularly limited as long as it exhibits a predetermined strength after curing, but in this embodiment, it is composed of, for example, a thermosetting resin such as epoxy resin as the main component. The resin impregnated into the reinforcing fibers is composed of, for example, epoxy resin as the main component, mixed with a curing agent and a curing accelerator in a predetermined ratio.

[0022] <<Method for Manufacturing Pressure Container According to First Embodiment>> Next, a method for manufacturing a pressure container according to this embodiment will be described. The method for manufacturing a pressure container according to this embodiment includes a liner forming step, a groove forming step, a reinforcing layer forming step, and a resin impregnation step.

[0023] The liner forming step is a step of forming a liner 2 having a cylindrical body portion 21, a shoulder portion 22, and a head portion 23. The molding method of the liner 2 is not particularly limited, but it can be molded by, for example, blow molding or injection molding.

[0024] The groove forming step is a step of forming grooves 25 in the protrusions 27 formed in the first boundary portions 24. There are no particular limitations on the method of forming the grooves 25, but the grooves 25 may be formed by cutting after the liner 2 is formed, or the grooves 25 may be formed together when the liner 2 is molded in the liner forming step.

[0025] The reinforcing layer forming process is a process in which a fiber-reinforced resin is wound around the outer periphery of the liner 2 and the mouthpiece 3 using a filament winding method to form the reinforcing layer 4. In the reinforcing layer forming process, the fiber-reinforced resin is wound while only the resin of the fiber-reinforced resin enters the groove portion 25. In the reinforcing layer forming process, low-angle helical winding, high-angle helical winding, and hoop winding are performed in an appropriate combination. The shoulder portion 22 is wound using high-angle helical winding or a combination of high-angle helical winding and low-angle helical winding.

[0026] The resin impregnation process is a process of allowing the resin impregnated in the fiber-reinforced resin to enter the grooves 25. Because the fiber-reinforced resin (bundle of fibers) is wound around the liner 2 while tension is applied, the resin seeps out and enters the grooves 25 both during and after winding. The resin that seeps out from the fiber-reinforced resin enters the grooves 25 and hardens, thereby fixing the reinforcing layer to the liner 2. Note that in this embodiment, the resin impregnation process has been described as occurring when the resin is (intentionally) caused to seep out and enter the grooves 25 due to the winding of the fiber-reinforced resin in the reinforcing layer formation process, but the present invention is not limited to this. In other words, the resin impregnation process also includes the phenomenon in which the resin impregnated in the fiber-reinforced resin naturally seeps out and enters the grooves 25, regardless of the winding of the fiber-reinforced resin in the reinforcing layer formation process.

[0027] In the conventional container structure, the curved shoulder portion 22 causes a problem in that the fiber-reinforced resin wound around the liner during the reinforcing layer formation process is displaced. In particular, the first boundary portion 24 and the second boundary portion 26 (described later) are areas where the curvature changes significantly, making displacement prone to occur. If the fiber-reinforced resin is displaced, the reinforcing layer 4 may peel off from the liner 2.

[0028] In this regard, according to the pressure vessel 1 and the manufacturing method for the pressure vessel 1 of this embodiment, a groove 25 is provided in the first boundary portion 24, which is a portion where the curvature changes significantly, and resin is allowed to enter the groove 25. As a result, the resin that seeps out from the reinforcing layer 4 enters the groove 25 and hardens, creating an anchor effect and allowing the reinforcing layer 4 to be fixed (anchored) to the liner 2. Therefore, it is possible to prevent displacement of the fiber-reinforced resin with a simple configuration.

[0029] Furthermore, a protrusion 27 that is thicker than other portions is provided at the first boundary portion 24, and a groove 25 is provided in the protrusion 27. This prevents a decrease in the strength of the liner 2 even when the groove 25 is provided. Furthermore, the outer peripheral surface 22a of the shoulder portion 22, the outer peripheral surface 3c of the flange portion 3a, and the outer peripheral surface 27a of the protrusion 27 are generally flush. This prevents steps from occurring on these outer peripheral surfaces even when the protrusion 27 is provided, and prevents stress concentration in the pressure vessel 1. The configuration of the groove is not limited to the embodiment described above, and can be modified as appropriate.

[0030] <Modification 1 of Groove Portion of First Embodiment> As shown in Fig. 4, groove portion 25A according to Modification 1 differs from the first embodiment in that it is configured with two grooves provided near the top of protrusion 27. Like groove portion 25A according to Modification 1, it may be configured with multiple grooves. The number of grooves may be three or more. The groove widths and depths of the two grooves may be the same or different.

[0031] 5, groove portion 25B according to modification 2 is configured with two grooves, and opens to the top and outer peripheral surface 27a of protrusion 27. In this manner, the grooves may be formed at positions shifted from the top of protrusion 27.

[0032] <Modification 3 of Groove Portion of First Embodiment> As shown in Fig. 6 , a groove portion 25C according to Modification 3 differs from the first embodiment in that it is composed of two grooves that are parallel to each other and that the angle of the grooves is inclined with respect to the central axis O. The angle of the grooves does not have to be parallel to the central axis O, as in groove portion 25C according to Modification 3. The angle of the grooves can be set appropriately within a range that allows the resin of the fiber reinforced resin to enter.

[0033] 7, a groove 25D according to a fourth modification differs from the first embodiment in that the groove has a triangular cross-sectional shape. The groove may have a triangular shape like groove 25D according to the fourth modification, or may have another shape.

[0034] <Modifications 5 and 6 of the Groove Portion of the First Embodiment> As shown in Fig. 8 , a groove portion 25E according to Modification 5 differs from the first embodiment in that the groove has a triangular shape in cross section and is inclined with respect to the central axis O. The groove portion 25E opens onto the outer peripheral surface 27a of the protrusion 27. As with groove 25E according to Modification 5, the groove may have a triangular shape or another shape. Furthermore, as with groove 25F according to Modification 6 shown in Fig. 9 , two grooves may have a triangular shape in cross section and both may open onto the outer peripheral surface 27a of the protrusion 27.

[0035] <Pressure vessel according to a second embodiment> Next, a description will be given of a pressure vessel and a method for manufacturing a pressure vessel according to a second embodiment. As shown in Fig. 10 , the pressure vessel 1A according to the second embodiment differs from the first embodiment in that a groove portion is formed in the second boundary portion 26.

[0036] The groove 29 is formed so as to be concave from the outer peripheral surface of the second boundary 26 toward the central axis O. The groove 29 opens radially outward before the reinforcing layer forming process is performed. As in the second embodiment, the groove 29 may be provided at the second boundary 26. In other words, since the groove 29 is formed at the second boundary 26, where displacement of the fiber-reinforced resin is particularly likely to occur, the resin of the fiber-reinforced resin can enter the groove 29, preventing displacement of the fiber-reinforced resin. Note that grooves may be formed at both the first boundary 24 and the second boundary 26.

[0037] 11 , groove portion 29A according to modification 1 differs from the second embodiment in that it is formed by two grooves. Like groove portion 29A according to modification 1, it may be formed by a plurality of grooves. The widths and depths of the two grooves may be the same or different.

[0038] <Modifications 2 and 3 of the Groove Portion of the Second Embodiment> As shown in Fig. 12 , a groove portion 29B according to Modification 2 differs from the second embodiment in that the groove has a triangular shape in cross section. The groove may have a triangular shape like groove portion 29B according to Modification 2, or another shape. Furthermore, as shown in Fig. 13 , a groove portion 29C according to Modification 3 has two triangular grooves in cross section. A plurality of triangular grooves may be formed in this manner.

[0039] While the embodiment of the present invention has been described above, appropriate design modifications are possible within the scope of the present invention. For example, grooves of different shapes may be combined. Furthermore, the protrusions (thick portions) 27 may be omitted if the strength of the liner 2 can be ensured.

[0040] REFERENCE SIGNS LIST 1 Pressure vessel 2 Liner 3 Mouthpiece 4 Reinforcing layer 21 Body 22 Shoulder 23 Head 24 First boundary 25 Groove 26 Second boundary 27 Projection (thick wall portion) 29 Groove

Claims

1. A pressure vessel comprising a liner having a cylindrical body, a head on which a nozzle is disposed, and a shoulder between the body and head which tapers in diameter towards the head; and a reinforcing layer formed by winding resin-impregnated fiber around the outer circumferential surface of the liner, wherein a groove is formed in at least one of a first boundary between the head and shoulder and a second boundary between the body and shoulder, and resin that has seeped out from the reinforcing layer fills the groove.

2. A pressure vessel as described in claim 1, characterized in that the first boundary portion has a thick portion or a protruding portion that is thicker than other portions, and the groove portion is formed in the thick portion or the protruding portion.

3. A method for manufacturing a pressure vessel, comprising: a liner forming step of forming a liner having a cylindrical body, a head on which a nozzle is disposed, and a shoulder between the body and head which tapers in diameter towards the head; a groove forming step of forming a groove in at least one of a first boundary between the head and shoulder and a second boundary between the body and shoulder; a reinforcing layer forming step of winding resin-impregnated fiber around the outer circumferential surface of the liner to form a reinforcing layer; and a resin impregnation step of allowing the impregnated resin to enter the groove.

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