Methods for manufacturing pressure vessels

Abstract

This invention provides a method for manufacturing a pressure vessel that can suppress resin from entering the thread groove, thereby preventing situations where it is impossible to install the joint and fastener (manifold). The method includes: a fiber winding process (S22), in which fibers are wound onto the outer surface of an inner liner (12) having a cylindrical open end (14) to form a fiber layer (17); a joint installation process (S24), in which multiple joint structures (22) are connected and fixed circumferentially at the open end (14), and a cylindrical joint (20) composed of multiple joint structures (22) is installed on the outer peripheral surface of the open end (14) via the fiber layer (17); a resin impregnation molding process (S25), in which resin is impregnated into the fiber layer (17); and a thread groove forming process (S27), in which an external thread (29) is formed on the outer surface of the cylindrical joint (20).

Description

Technical Field

[0001] This invention relates to a method for manufacturing pressure vessels. Background Technology

[0002] A pressure vessel (also known as a high-pressure tank, etc.) is known in the past, comprising a cylindrical liner and a reinforcing portion (reinforcing layer) formed of carbon fiber reinforced resin (CFRP) to reinforce the liner, wherein the pressure vessel stores hydrogen inside (for example, see Patent Document 1). A connector is securely mounted at the end of the liner of the pressure vessel. That is, a protrusion provided at the connector engages with the reinforcing portion (reinforcing layer).

[0003] The pressure vessel described in Patent Document 1 comprises: a liner filled with gas; a reinforcing layer formed of fiber-reinforced resin in contact with the outer surface of the liner and covering the liner from the outside; and a connector installed on the liner. The connector is formed in an annular shape and comprises: a plurality of connector body portions having locking claws (protrusions) protruding toward the reinforcing layer side, and the plurality of connector body portions being arranged at intervals in the circumferential direction; and a crossbeam portion connecting the plurality of circumferentially adjacent connector body portions in the circumferential direction. The connector is installed on the liner in a state where the locking claws (protrusions) of the plurality of connector body portions are locked in place by deformation of the crossbeam portion against the reinforcing layer.

[0004] The pressure vessel can be manufactured, for example, by a fiber winding (FW) method in which sheet-like fiber-reinforced resin is bonded to the liner (Patent Document 1), or by an RTM (Resin Transfer Molding) method in which sheet-like fibers (bundles) are bonded to the liner and then resin is impregnated (Patent Document 2).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-112190

[0008] Patent Document 2: Japanese Patent Application Publication No. 2020-085199

[0009] Patent Document 3: Japanese Patent Application Publication No. 2021-076174 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] If the reinforcing layer reaches high temperatures during pressure vessel use, the reinforcing layer of the connector locking portion may sometimes shrink and deform. When the reinforcing layer shrinks and deforms, the crossbeam portion, which is the deformable part of the connector, also deforms, and the threaded groove (external thread portion) formed on the outer periphery of the connector body and the fastening portion (manifold) may loosen. This is because the connector is an annular component to prevent resin from spreading to the external thread portion during RTM, and it is constructed with a crossbeam portion that can be reduced in diameter to allow the locking claws (protrusions) to insert (engage). To address this concern, a split connector (see Patent Document 3) is considered, which divides the connector, which is made of a rigid body, circumferentially.

[0012] For example, the pressure vessel described in Patent Document 3 includes: a container body having a cylindrical open end at at least one end and being filled with gas inside; a cover made of fiber-reinforced resin covering the outer surface of the container body; and a cylindrical connector formed by connecting multiple connector bodies having protrusions on their inner surfaces circumferentially at the open end, which is installed on the outer circumferential surface of the open end by having the protrusions bite into the cover covering the outer circumferential surface of the open end, and the connector is connected by fitting the fitting portions formed at the circumferential ends of the connector bodies.

[0013] However, in the aforementioned conventional pressure vessels, when the pressure vessel is manufactured using the RTM method, which involves winding fibers (bundles) around the liner and assembling the joint from the outside of the fibers (bundles) and then impregnating it with resin, the resin may enter the threaded grooves pre-formed on the outer periphery of the joint body during resin impregnation, potentially making it impossible to install the joint and fastener (manifold).

[0014] In view of the above, the object of the present invention is to provide a method for manufacturing a pressure vessel that can suppress the entry of resin into the thread groove, thereby preventing the inability to install the joint and fastener (manifold).

[0015] Technical solutions for solving the problem

[0016] To achieve the above objectives, the manufacturing method of the pressure vessel of the present invention is characterized by comprising the following steps: a fiber winding step, wherein fibers are wound onto the outer surface of a liner to form a fiber layer, the liner having a cylindrical open end and being filled with gas; a joint installation step, wherein a plurality of joint structures are connected and fixed circumferentially at the open end, and a cylindrical joint composed of the plurality of joint structures is installed on the outer peripheral surface of the open end via the fiber layer; a resin impregnation molding step, wherein resin is impregnated into the fiber layer; and a thread groove forming step, wherein an external thread portion is formed on the outer surface of the cylindrical joint.

[0017] In a preferred embodiment, during the joint installation process, a plurality of joint structures are fixed in a state in which the circumferential ends of adjacent joint structures are in contact.

[0018] In another preferred embodiment, the connector structure comprises four parts.

[0019] In another preferred embodiment, during the connector installation process, the connector structure is pressed against the outer periphery of the fiber layer by causing the protrusions on the inner surface of the connector structure to bite into the fiber layer formed on the outer peripheral surface of the opening end. After the four connector structures are pressed against the outer periphery of the fiber layer at 90-degree intervals in their pressing directions toward the outer periphery of the fiber layer, the four connector structures are fixed.

[0020] In another preferred embodiment, the four joint structures have two sets of joint structure pairs facing each other in the pressing direction toward the outer periphery of the fiber layer. In the joint installation process, after pressing one set of the two sets of joint structure pairs against the outer periphery of the fiber layer, the other set of the two sets of joint structure pairs is pressed against the outer periphery of the fiber layer, and then the four joint structures are fixed.

[0021] In another preferred embodiment, the four joint structures have two sets of joint structure pairs facing each other in the pressing direction toward the outer periphery of the fiber layer. In the joint installation process, after the two sets of joint structure pairs are pressed against the outer periphery of the fiber layer simultaneously, the four joint structures are fixed.

[0022] Invention Effects

[0023] According to the present invention, by forming a threaded groove (external thread) for mounting a fastener (manifold, etc.) to a connector after the resin impregnation molding process, it is possible to suppress the entry of resin into the threaded groove, thereby preventing the inability to install the connector and the fastener (manifold, etc.).

[0024] In addition, by setting four joint structures, the deviation between the installation direction of the joint structure and the direction in which the protrusion on the inner surface of the joint structure bites into the reinforcing layer can be reduced, thus ensuring that the joint and the reinforcing layer are firmly locked together. Attached Figure Description

[0025] Figure 1 This is an enlarged cross-sectional view showing the open end side of the pressure vessel involved in this embodiment.

[0026] Figure 2 This is an enlarged perspective view of the open end side of the pressure vessel involved in this embodiment.

[0027] Figure 3 This is a perspective view showing the connector involved in this embodiment.

[0028] Figure 4 This is an enlarged cross-sectional view showing the locking claws of the connector involved in this embodiment.

[0029] Figure 5 This is a process diagram illustrating the manufacturing method (RTM method) of the pressure vessel involved in this embodiment.

[0030] Figure 6 This is an enlarged perspective view of the open end side of the pressure vessel involved in this embodiment, showing the state before the joint is fixed.

[0031] Figure 7 This is an enlarged front view of the pressure vessel's open end side according to this embodiment, showing its state before the connector is fixed.

[0032] Figure 8 This is an enlarged perspective view of the open end side of the pressure vessel involved in this embodiment, showing the state after the joint is fixed and before resin impregnation (before the thread groove is formed).

[0033] Figure 9 This is an enlarged front view of the pressure vessel's open end side according to this embodiment, showing the state after the joint is fixed and before resin impregnation (before the thread groove is formed).

[0034] Figure 10 This is a perspective view showing another example of the connector involved in this embodiment. Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. Furthermore, for ease of explanation, arrows S, appropriately indicated in the figures, will represent the axial direction of the pressure vessel 10, arrow R the radial direction of the pressure vessel 10, and arrow C the circumferential direction of the pressure vessel 10. Therefore, in the following description, unless otherwise specified, axial, radial, and circumferential directions respectively represent the axial, radial, and circumferential directions of the pressure vessel 10 (including the open end 14 described later).

[0036] (Simplified structure of a pressure vessel)

[0037] like Figure 1 As shown, the pressure vessel 10 according to this embodiment constitutes part of the tank module (not shown) mounted on a fuel cell vehicle (not shown). Furthermore, the tank module is configured to include multiple pressure vessels 10 interconnected via fastening parts 18, etc., as described later.

[0038] The pressure vessel 10 is configured to include: a liner 12, which serves as the main body of the vessel and is filled with gaseous hydrogen; a reinforcing layer 16, which serves as a cover that reinforces the outer surface of the liner 12 from the outside; and a cylindrical connector 20, which is installed via the reinforcing layer 16 onto the outer peripheral surface of the cylindrical opening ends 14 formed at both ends of the liner 12.

[0039] The liner 12 is formed into a generally cylindrical shape using a resin material such as polyamide synthetic resin. More specifically, the liner 12 has: a main body portion 12A with a constant inner and outer diameter at the middle portion along the length direction (axial direction) of the liner 12; and shoulder portions 12B that constitute the two sides along the length direction (axial direction) of the liner 12 and gradually narrow towards the side opposite to the main body portion 12A (outer axial direction).

[0040] Furthermore, the liner 12 has a cylindrical open end 14, which constitutes the two ends of the liner 12 in the longitudinal direction (axial direction) (the part that is axially outer than the shoulder 12B), and has a smaller inner diameter and outer diameter than the main body 12A and the shoulder 12B and is formed to be approximately constant.

[0041] The reinforcing layer 16 is made of fiber-reinforced resin and is formed by winding multiple layers of reinforcing fibers (bundles) around the entire outer surface of the liner 12 and impregnating the wound fibers (layers) with resin. Furthermore, the thickness of the reinforcing layer 16 is configured to increase from the main body portion 12A side of the liner 12 towards the opening end 14 side. Additionally, the outer diameter of the portion of the reinforcing layer 16 corresponding to the opening end 14 of the liner 12 is approximately constant. In this embodiment, carbon fiber reinforced resin (CFRP) is used as an example of fiber-reinforced resin (FRP).

[0042] Additionally, a connector 20 is installed over the reinforcing layer 16 at the opening end 14 of the liner 12, which is covered by the reinforcing layer 16. Then, a fastening part 18 is installed on the connector 20. Thus, the opening end 14 on one side of the liner 12 is closed by the fastening part 18, and the opening end on the other side of the liner 12 (not shown) is connected to other pressure vessels 10 via the fastening part (not shown). Furthermore, in Figure 1 The image shows the opening end 14 on one side of the liner 12 that is closed by the fastener 18.

[0043] (Connector structure)

[0044] like Figure 2 , Figure 3As shown, the connector 20 is formed into a cylindrical (ring-shaped) form using a metallic material. Specifically, the connector 20 is composed of a plurality of connector structures 22 arranged circumferentially (four in this embodiment). The connector structures 22 extend axially in the radial direction of thickness and are formed into a plate-like shape that bends radially outward when viewed from the axial direction.

[0045] Furthermore, the outer end face of the connector structure 22 has a flat surface 23 that is flush with the end face of the opening end 14 (reinforcing layer 16), and a flange portion 24 that bends radially outward is integrally formed at the inner end face of the connector structure 22. In addition, the flange portion 24 of each connector structure 22 is formed such that, when viewed from the axial direction, the assembled shape is approximately a regular octagon.

[0046] like Figure 1 , Figure 3 As shown, multiple locking claws 26, which serve as protrusions, are formed on the inner circumferential surface (inner surface) of each connector structure 22. Through these multiple locking claws 26, the inner circumferential surface of each connector structure 22 becomes knurled. Each locking claw 26 is formed as a sharp serration on the front end side (radial inner side) in the protruding direction when viewed in cross-section along the axial and radial directions.

[0047] To explain in more detail, such as Figure 4 As shown, the surface of each locking claw 26 facing the main body portion 12A of the inner liner 12 becomes an inclined surface 26A that slopes outward axially as it moves radially inward. Furthermore, the surface of each locking claw 26 opposite to the surface facing the main body portion 12A of the inner liner 12 becomes a vertical surface 26B along the radial direction.

[0048] Furthermore, the portion where the inclined surface 26A intersects with the vertical surface 26B becomes the front end portion 26C of each locking claw 26. The structure is such that the front end portion 26C of each locking claw 26 bites (locks) into the outer periphery of the reinforcing layer 16 covering the outer periphery of the opening end 14, thereby the connector 20 is securely (non-rotatably) installed on the opening end 14.

[0049] In addition, such as Figure 1 , Figure 2 , Figure 3 As shown, threaded grooves 28 are formed on the outer peripheral surface (outer surface) of each connector structure 22. This results in a structure whereby, through these threaded grooves 28, when the connector 20 is installed to the opening end 14 (when each connector structure 22 is connected and fixed), a helical external thread 29 is formed along both the circumferential and axial directions (the method of forming the threaded grooves 28 or the external thread 29 will be described later). Furthermore, the internal thread 19 of the fastening portion 18, described later, engages with this external thread 29.

[0050] In addition, such as Figure 2 , Figure 3 As shown, a connecting and fixing portion 30 for connecting and fixing the joint structures 22 circumferentially is formed at the circumferential end of each joint structure 22. In this embodiment, the connecting and fixing portion 30 is configured as a riveting fixing portion for connecting and fixing the plurality of joint structures 22 arranged circumferentially to each other. The connecting and fixing portion 30 consists of a riveting hole 32 that serves as a through hole. Figure 6 It consists of a rivet hole 32 formed at the circumferential end of a joint structure 22 adjacent to the joint 20 in the circumferential direction, and a rivet protrusion 34 formed at the circumferential end of another joint structure 22 adjacent to the joint 20 in the circumferential direction.

[0051] To be more specific, the connector 20 of this embodiment is composed of four connector structures, including a pair of connector structures formed in the same shape (upper and lower) and a pair of connector structures formed in the same shape (left and right).

[0052] The outer peripheral sides of the circumferential (i.e., left and right) ends (four locations) of the paired joint structures 22 are cut off to form a planar shape. Riveting holes 32 are formed at two axial locations (a total of eight locations) at the aforementioned planar fixing portions 33 (see reference). Figure 6 , Figure 7 ).

[0053] Riveting protrusions 34 are formed at four circumferential (i.e., upper and lower) ends of the paired left and right joint structures 22, and at two axial locations pointing upwards or downwards (a total of eight locations) (see reference). Figure 6 , Figure 7 In addition, the vertical length of the riveting protrusion 34 is longer than the vertical depth (length) of the riveting hole 32.

[0054] Furthermore, a riveting protrusion 34 of an adjacent joint structure 22 (a left-right joint structure 22 in this embodiment) is inserted into the riveting hole 32 of an adjacent joint structure 22 (a vertical joint structure 22 in this embodiment). The front end of the riveting protrusion 34 protruding from the riveting hole 32 is pressed and deformed to widen the front end (widening it to a diameter larger than the riveting hole 32). This widened deformed portion 35 is pressed against the riveting hole 32 of the fixing portion 33 (in other words, the fixing portion 33 is held in place by two widened deformed portions 35 arranged axially). Thus, each joint structure 22 is connected and fixed in the circumferential direction (see reference). Figure 8 , Figure 9 That is, forming a cylindrical joint 20.

[0055] The structure is such that when the riveting protrusion 34 is inserted into the riveting hole 32, and the joint structures 22 are interconnected and fixed in the circumferential direction, the circumferential end (face) 22A of an adjacent joint structure 22 abuts against the circumferential end (face) 22B of another adjacent joint structure 22. In other words, the structure is such that no gap is formed between the circumferential end (face) 22A of an adjacent joint structure 22 and the circumferential end (face) 22B of another adjacent joint structure 22 (see reference). Figures 6-9 ).

[0056] (Manufacturing process of pressure vessels)

[0057] Next, the process of manufacturing the pressure vessel 10 according to this embodiment, in particular the process of installing the connector 20 according to this embodiment onto the opening end 14 of the liner 12 and forming an external thread 29 on the installed connector 20, will be described.

[0058] The manufacturing process of this embodiment is a process of manufacturing pressure vessel 10 using the RTM method, such as in... Figure 5 As shown in one example, it includes a liner forming process (S21), a fiber winding process (S22), a joint configuration process (S23), a joint installation process (S24), a resin impregnation molding process (S25), a demolding process (S26), a threaded groove forming process (S27), and a fastener installation process (S28).

[0059] First, a roughly cylindrical inner liner 12 is formed (inner liner forming process: S21).

[0060] Next, sheet-like fibers (bundles) are wound onto the outer surface of the liner 12 (fiber winding process: S22). Carbon fiber (CF) is used as an example of the fiber. By winding the fibers (bundles) onto the liner 12, a fiber layer 17 is formed on the outer surface of the liner 12. Figures 6 to 9 Additionally, at this time, the fibers (bundles) are wound in a manner that makes the fiber layer 17 at the opening end 14 thicker than that at the main body 12A and shoulder 12B.

[0061] Alternatively, the liner forming process (S21) and the fiber winding process (S22) can be referred to together as the intermediate preparation process for preparing an intermediate body to be formed by winding fibers (bundles) on the outer surface of the liner 12.

[0062] Then, as Figure 6 , Figure 7As shown, a connector 20 is disposed on the outer periphery of the opening end 14 of the liner 12 (outer periphery of the fiber layer 17) (connector disposal step: S23). That is, a plurality of connector structures 22 constituting the connector 20 (without threaded grooves 28 formed here) are disposed in the circumferential direction of the opening end 14. As a result, the front ends 26C of the numerous locking claws 26 formed on each connector structure 22 of the connector 20 are disposed opposite (with gaps) to the outer periphery of the fiber layer 17.

[0063] Next, as Figure 8 , Figure 9 As shown, the connector 20 (the plurality of connector structures 22 constituting the connector 20) is brought close to the fiber layer 17 (tightened), and the connecting fixing part 30 of the connector 20 is connected and fixed, thereby reducing the diameter of the connector 20 (connector installation step: S24). That is, the left and right paired connector structures 22 are moved radially inward, and their inner peripheral surfaces (the plurality of locking claws 26) (from the left and right direction) are pressed against the outer peripheral portion of the fiber layer 17 for retention. Next, the upper and lower paired connector structures 22 are moved radially inward, and while the riveting protrusions 34 of the left and right connector structures 22 are inserted into the riveting holes 32 of the upper and lower connector structures 22, the inner peripheral surfaces (the plurality of locking claws 26) (from the upper and lower direction) of the upper and lower paired connector structures 22 are pressed against the outer peripheral portion of the fiber layer 17 for retention. Then, the front end of the riveting protrusion 34 protruding from the riveting hole 32 is pressed and deformed to widen the front end (widening it to a diameter larger than the riveting hole 32), and the widened deformed part 35 is pressed against the riveting hole 32 of the fixing part 33 (in other words, the fixing part 33 is clamped and held by two widened deformed parts 35 arranged in the axial direction). As a result, each joint structure 22 moves radially inward (reducing its diameter), and the circumferential end (face) 22A of an adjacent joint structure 22 abuts against the circumferential end (face) 22B of another adjacent joint structure 22. At the same time, the adjacent joint structures 22 are connected and fixed to each other, and multiple locking claws 26 bite into the fiber layer 17. As a result, the joint 20 is installed on the outer peripheral surface of the opening end 14 of the liner 12 via the fiber layer 17.

[0064] The inner liner 12, with a connector 20 (without a threaded groove 28 or external thread 29) installed at the open end 14, is placed in a mold. Resin is injected into the mold to impregnate the fiber layer 17, thereby forming a reinforcing layer 16 made of fiber-reinforced resin (resin impregnation molding process: S25). As a result, a plurality of locking claws 26 are locked onto the reinforcing layer 16.

[0065] Remove the inner liner 12 with the reinforcing layer 16 formed from the mold (demolding) (demolding process: S26).

[0066] Next, a helical external thread 29 is formed on the outer periphery (outer surface) of the connector 20 installed at the opening end 14 of the liner 12 (thread groove forming process: S27). Figure 2 In other words, a plurality of threaded grooves 28 of joint structures 22, which are continuously (simultaneously) connected and fixed in the circumferential direction at the opening end 14 of the liner 12, are formed.

[0067] Then, by screwing the helical internal thread 19 formed on the fastener 18 into the external thread 29 formed on the connector 20, the fastener 18 is installed on the opening end 14 of the liner 12, thereby manufacturing the pressure vessel 10 (fastener installation step: S28).

[0068] (The function and effects of this implementation method)

[0069] The manufacturing method of the pressure vessel 10 of the present embodiment described above includes: a fiber winding process (S22), in which fibers are wound around the outer surface of an inner liner 12 having a cylindrical open end 14 and filled with gas to form a fiber layer 17; a connector installation process (S24), in which a plurality of connector structures 22 are connected and fixed in the circumferential direction of the open end 14, and a cylindrical connector 20 composed of a plurality of connector structures 22 is installed on the outer peripheral surface of the open end 14 via the fiber layer 17; a resin impregnation molding process (S25), in which resin is impregnated into the fiber layer 17; and a thread groove forming process (S27), in which an external thread portion 29 is formed on the outer surface of the cylindrical connector 20.

[0070] That is, in this embodiment, the connector 20 is constructed by dividing it into sections, and the connector 20 is locked onto the fiber layer 17 (the reinforcing layer 16 before resin impregnation). The reinforcing layer 16 is formed by resin impregnation, and then an external thread portion 29 (thread groove 28) is formed on the connector 20. The connector 20 does not shrink in diameter due to the combination of multiple connector structures 22, thereby allowing the process of forming the external thread portion 29 (thread groove 28) on the connector 20 to be performed after the connector 20 is installed.

[0071] According to this embodiment, by forming a threaded groove 28 (external thread 29) for mounting the fastening part 18 (manifold, etc.) to the connector 20 after the resin impregnation molding process, it is possible to suppress the entry of resin into the threaded groove 28, thereby preventing the connector 20 and the fastening part 18 (manifold, etc.) from being unable to be installed.

[0072] Furthermore, in the manufacturing method of the pressure vessel 10 of this embodiment, in the aforementioned connector installation step (S24), the connector structure 22 is held against the outer periphery of the fiber layer 17 by having multiple locking claws 26, which are protrusions provided on the inner surface of the connector structure 22, bite into the fiber layer 17 formed on the outer periphery of the opening end 14. In this case, in order for the multiple locking claws 26 to effectively bite into the fiber layer 17, the angular interval between adjacent connector structures 22 in the pressing direction (installation direction) towards the outer periphery of the fiber layer 17 is preferably 90 degrees or less. In addition, the number of multiple connector structures 22 constituting the connector 20 is preferably as small as possible. Therefore, the number of multiple connector structures 22 constituting the connector 20 is preferably four.

[0073] In the manufacturing method of the pressure vessel 10 of this embodiment, the number of the above-mentioned joint structures 22 is four. In addition, after pressing the four joint structures 22 against the outer periphery of the fiber layer 17 with the angle between adjacent joint structures 22 and the pressing direction (installation direction) towards the outer periphery of the fiber layer 17 being 90 degrees apart (in other words, with the pressing direction of the four joint structures 22 towards the outer periphery of the fiber layer 17 being 90 degrees apart), the four joint structures 22 are fixed.

[0074] More specifically, the four connector structures 22 have two sets (a pair of left and right connector structures 22 and a pair of top and bottom connector structures 22) facing each other in the pressing direction towards the outer periphery of the fiber layer 17 (at a 180-degree interval). After pressing one set of connector structures (a pair of left and right connector structures 22 in this embodiment) against the outer periphery of the fiber layer 17, the other set of connector structures (a pair of top and bottom connector structures 22 in this embodiment) against the outer periphery of the fiber layer 17 is pressed, and then the four connector structures 22 are fixed.

[0075] According to this embodiment, by providing four connector structures 22, the deviation between the installation direction of the connector structure 22 and the direction in which the protrusions (multiple locking claws 26) provided on the inner surface of the connector structure 22 bite into the reinforcing layer 16 can be reduced, thus enabling the connector 20 to be securely locked to the reinforcing layer 16.

[0076] The pressure vessel 10 according to this embodiment has been described above based on the accompanying drawings. However, the pressure vessel 10 according to this embodiment is not limited to the structure shown in the drawings, and appropriate design changes can be made without departing from the spirit of the invention. For example, the liner 12 only needs to have a cylindrical open end 14 at least on one end side.

[0077] Furthermore, the gas filling the liner 12 is not limited to hydrogen. For example, gases such as helium and nitrogen can also be filled into the liner 12. In addition, the reinforcing layer 16 can be made of fiber reinforced resin (FRP) and is not limited to carbon fiber reinforced resin (CFRP).

[0078] Furthermore, the number of joint structures 22 constituting the joint 20 is not limited to the four shown in the figure. The number of joint structures 22 constituting the joint 20 can be appropriately designed and modified according to the outer diameter of the opening end 14 (including the thickness of the reinforcing layer 16) and the circumferential length of the joint structure 22.

[0079] Furthermore, the connecting and fixing part 30, which connects and fixes the multiple joint structures 22 constituting the joint 20 to each other, is not limited to the riveting fixation shown in the figure. For example, the multiple joint structures 22 can also be connected and fixed to each other by bolt fastening, welding, fusion, bonding, etc., thereby being installed on the outer peripheral surface of the opening end 14. Figure 10 The diagram shows an example of a cylindrical joint 20 formed by connecting and fixing multiple joint structures 22 together with bolts, and shows the use of bolts 38 instead of bolts. Figure 3 Examples of riveting protrusions 34 and widened deformation portions 35. For example, in this case, during the joint installation process (S24), after simultaneously pressing the two sets of joint structure pairs 22 (a left-right pair of joint structure pairs 22 and a top-bottom pair of joint structure pairs 22) against the outer periphery of the fiber layer 17, the four joint structures 22 can be fixed, thereby shortening the assembly time required for the joint 20. Alternatively, it can be replaced with Figure 3 The bolt is formed by the riveting protrusion 34 (protruding setting) and the nut is provided on the fixing part 33 side, and the bolt and nut are connected and fixed.

[0080] Label Explanation

[0081] 10 Pressure Vessels

[0082] 12 Lining

[0083] 14 Open end

[0084] 16. Reinforcing layer (covering part)

[0085] 18 Fastening parts

[0086] 19 Internal thread section

[0087] 20 connectors

[0088] 22. Joint structure

[0089] 26. Locking claw (protrusion)

[0090] 28 Threaded groove

[0091] 29 External thread section

[0092] 30 Connecting and fixing parts

[0093] 32. Riveting hole (through hole)

[0094] 33 Fixing part

[0095] 34. Riveting protrusion (through protrusion)

[0096] 35 Widened deformation section

Claims

1. A method of manufacturing a pressure vessel, characterized by, comprises the following steps: a fiber winding step of winding a fiber on an outer surface of an inner liner to form a fiber layer, the inner liner having a cylindrical open end portion and being filled with a gas inside; a joint attaching step of joining and fixing four joint structures in the circumferential direction of the open end portion, and attaching a cylindrical joint composed of the four joint structures to an outer peripheral surface of the open end portion via the fiber layer; a resin impregnation molding step of impregnating a resin into the fiber layer; and a thread groove forming step of forming an external thread portion on an outer surface of the cylindrical joint, in the joint attaching step, the joint structures are pressed against the outer peripheral portion of the fiber layer by making a protrusion portion provided on an inner surface of the joint structure bite into the fiber layer formed on the outer peripheral surface of the open end portion, and after the four joint structures are pressed against the outer peripheral portion of the fiber layer at 90-degree intervals in the direction in which the four joint structures are pressed against the outer peripheral portion of the fiber layer, the four joint structures are fixed, the four joint structures have two pairs of joint structures facing each other in the direction in which the joint structures are pressed against the outer peripheral portion of the fiber layer, in the joint attaching step, after one of the two pairs of joint structures is pressed against the outer peripheral portion of the fiber layer, the other of the two pairs of joint structures is pressed against the outer peripheral portion of the fiber layer, and then the four joint structures are fixed.

2. The method of manufacturing a pressure vessel according to claim 1, wherein in the joint attaching step, the four joint structures are fixed in a state in which end portions in the circumferential direction of the adjacent joint structures are in contact with each other.

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