Tank manufacturing method

Abstract

To provide a method for manufacturing a tank capable of confirming quality of a liner even when the liner is integrated with a nozzle.SOLUTION: A method for manufacturing a tank 10 comprises: forming two or more liner split bodies, including an opening split body having an opening part 13 formed therein, and a nozzle 14; press-fitting the nozzle 14 into the opening part 13 of the opening split body; joining the opening split body and the nozzle 14 by heating an overlapping part 130 of the opening split body with the nozzle 14 from inside the opening split body; and forming a liner 11 by assembling two or more liner split bodies including the opening split body.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a tank.

Background Art

[0002] Conventionally, as such a technical field, for example, there is one described in Patent Document 1. The tank described in Patent Document 1 includes a liner having a tank shape and a base integrated with the liner and having a flange portion. The flange portion of the base is provided with a key groove and a plurality of holes for preventing the liner from falling off.

[0003] When manufacturing a tank having such a structure, first, a metal base provided with a key groove and a plurality of holes in the flange portion is formed. Next, the liner is formed by insert molding so that the liquid polymer material flows into the key groove and the plurality of holes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above-described method for manufacturing a tank, in order to integrate the base and the liner by insert molding, for example, when inspecting foreign matters, voids, etc. in the joint portion between the liner and the base by X-rays, halation occurs in the vicinity of the base, and the problem that the quality of the liner cannot be confirmed occurs.

[0006] The present invention has been made to solve such technical problems, and an object thereof is to provide a method for manufacturing a tank that can confirm the quality of the liner even when the liner and the base are integrated.

Means for Solving the Problems

[0007] The present invention relates to a method for manufacturing a tank comprising a resin liner having an opening and a metal nozzle pressed into the opening, and is characterized by comprising: a first step of forming two or more liner divisions, each including an opening division having the opening, and the nozzle; a second step of pressing the nozzle into the opening of the opening division; a third step of joining the opening division and the nozzle by heating the overlapping portion of the opening division with the nozzle from the inside of the opening division; and a fourth step of forming the liner by assembling the two or more liner divisions, each including the opening division.

[0008] In the tank manufacturing method according to the present invention, two or more liner divisions, each containing an opening division, and a nozzle are formed separately. After this, the nozzle is press-fitted into the opening of the opening division. Compared to conventional insert molding, the quality of the liner division can be checked before press-fitting the nozzle. As a result, even when the liner and nozzle are made as a single unit, the quality of the liner can be checked.

[0009] In the method for manufacturing a tank according to the present invention, it is preferable in the third step to place an infrared-transparent member from the inside of the opening division and, while the infrared-transparent member holds the overlapping portion of the opening division, heat the overlapping portion of the opening division with an infrared heater via the infrared-transparent member. In this way, the overlapping portion can be heated while maintaining the shape of the overlapping portion of the opening division with the infrared-transparent member.

[0010] In the method for manufacturing a tank according to the present invention, it is preferable that in the first step, anodizing treatment is applied to the surface of the opening division that contacts the overlapping portion of the opening division in the nozzle, and in the third step, heating is performed at a temperature below the melting point of the resin material forming the liner. By applying anodizing treatment to the surface of the opening division that contacts the overlapping portion of the opening division in the nozzle, it becomes possible to join the nozzle and the liner at a relatively low temperature. Therefore, even if the resin material forming the liner is heated at a temperature below the melting point, the nozzle and the liner can be joined. Moreover, since the resin material forming the liner is heated at a temperature below the melting point, it has the effect of suppressing the sagging of the resin material. [Effects of the Invention]

[0011] According to the present invention, even when the liner and the nozzle are integrated, the quality of the liner can be confirmed. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic cross-sectional view showing the structure of the tank. [Figure 2] This is a flow chart showing the manufacturing method of the tank according to the embodiment. [Figure 3] This is a cross-sectional view showing the formation of the liner division. [Figure 4] This is a cross-sectional view showing the press-fitting of the nozzle. [Figure 5] This is a schematic cross-sectional view showing that the overlapping portion of the first divided body or the open divided body is heated. [Modes for carrying out the invention]

[0013] The following describes an embodiment of the manufacturing method of the tank 10 with reference to the drawings, but before that, the structure of the tank 10 will be described based on Figure 1. The tank 10 is a high-pressure tank that is mounted on, for example, a fuel cell vehicle and filled with high-pressure hydrogen gas. The tank 10 is not limited to fuel cell vehicles and may be applied to other uses. Furthermore, the gas that can be filled into the tank 10 is not limited to hydrogen gas, but may be various compressed gases such as CNG (compressed natural gas), various liquefied gases such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas), or other gases.

[0014] Figure 1 is a schematic cross-sectional view showing the structure of the tank. The tank 10 is a substantially cylindrical storage container with dome-shaped rounded ends, and comprises a liner 11 having hydrogen gas barrier properties and a resin reinforcing layer 12 made of a fiber-reinforced resin material covering the outer surface of the liner 11. A substantially vase-shaped opening 13 (see Figure 3) is formed at one end of the liner 11 in the axial L direction, and a nozzle 14 is fitted to the opening 13. The other end of the liner 11 in the axial L direction has no opening and no nozzle.

[0015] The liner 11 is a resin component that forms a containment space 15 into which hydrogen gas is filled. The resin constituting the liner 11 is preferably a resin that has good performance in retaining the hydrogen gas being filled into the containment space 15, i.e., has good hydrogen gas barrier properties. Examples of such resins include thermoplastic resins such as polyamide, polyethylene, and ethylene-vinyl alcohol copolymer resin (EVOH) and polyester, and thermosetting resins such as epoxy.

[0016] The liner 11 of this embodiment is formed by assembling two or more liner segments including an opening segment with an opening 13 formed therein. As shown in, for example, FIG. 3(a), the liner 11 may be composed of three liner segments such as a dome-shaped first segment (opening segment) 111 with an opening 13 formed at its tip, a cylindrical second segment 112, and a dome-shaped third segment 113 located on the side opposite to the first segment 111. Alternatively, as shown in FIG. 3(b), it may be composed of two liner segments such as a substantially bell-shaped opening segment 114 with an opening 13 formed at its tip and a substantially bell-shaped non-opening segment 115 without an opening.

[0017] The base 14 is made by processing a metal material such as stainless steel or aluminum into a substantially pot shape. This base 14 has a neck portion 141 held by the resin reinforcing layer 12, a curved shoulder portion 142 having an outwardly bulging shape, and a tapered barrel portion 144 that gradually narrows in width from the curved shoulder portion 142 to the bottom portion 143. Further, a through hole 145 communicating with the accommodation space 15 of the tank 10 is provided at the center of the base 14.

[0018] The resin reinforcing layer 12 covers the outer surface of the liner 11 and has a function of reinforcing the liner 11 to improve the mechanical strength such as the rigidity and pressure resistance of the tank 10. Further, the resin reinforcing layer 12 is formed so as to cover the outer peripheral wall of the neck portion 141 of the base 14 and reinforces the joining state between the base 14 and the liner 11.

[0019] Hereinafter, a method for manufacturing the tank 10 will be described using FIGS. 2 to 5. As shown in FIG. 2, the method for manufacturing the tank 10 according to this embodiment includes a liner segment forming step S1, a base forming step S2, a base press-fitting step S3, a step S4 of joining the base and the liner by heating, a liner segment assembling step S5, and a resin reinforcing layer forming step S6.

[0020] The liner dividing body forming step S1 and the base forming step S2 correspond to the "first step" described in the claims. Since the liner dividing body forming step S1 and the base forming step S2 are independent steps, they may be performed in parallel or either step may be performed first.

[0021] In step S1, each liner dividing body is formed by injection molding using a resin material. As shown in Fig. 3(a), when the liner 11 is composed of three liner dividing bodies, for example, in a state where a thermoplastic resin is heated and melted, it is pushed into a mold at a predetermined injection pressure and solidified to form the first dividing body 111, the second dividing body 112, and the third dividing body 113 respectively. When forming the first dividing body 111, an opening 13 for press-fitting the base 14 is also formed simultaneously.

[0022] As shown in Fig. 3(a), with the formation of the opening 13, a surrounding portion 120 that surrounds and holds a part of the curved shoulder portion 142 of the base 14 from the outside and an overlapping portion 130 that overlaps with the inclined barrel portion 144 of the base 14 and supports the inclined barrel portion 144 are formed at the tip of the first dividing body 111 respectively. That is, the opening 13 is a space formed by the surrounding portion 120 and the overlapping portion 130.

[0023] Also, when forming the first dividing body 111 and the third dividing body 113, it is preferable that the thickness of the dome end portions of each becomes thinner from the inside to the outside, and the thickness of both ends in the axial direction L of the second dividing body 112 becomes thinner from the outside to the inside. In this way, when the first dividing body 111 and the third dividing body 113 are assembled and joined to the second dividing body 112 later, it becomes difficult to form a step at the joining portion.

[0024] On the other hand, as shown in Figure 3(b), when the liner 11 is composed of two liner divisions, for example, when a thermoplastic resin is heated to a high temperature and melted, it is pressed into a mold at a predetermined injection pressure and solidified to form an open division 114 and a non-open division 115, respectively. When forming the open division 114, an opening 13 for press-fitting the nozzle 14 is also formed at the same time. Similarly, with the formation of the opening 13, an enclosure portion 120 and an overlapping portion 130 are formed at the tip of the open division 114, respectively.

[0025] Furthermore, when forming the open section 114 and the non-open section 115, it is preferable that the thickness of the end portion of one of these liner sections (for example, the open section 114) decreases from the inside to the outside, and the thickness of the end portion of the other section (for example, the non-open section 115) decreases from the outside to the inside. This makes it less likely for a step to be formed at the joint when the open section 114 and the non-open section 115 are later assembled and joined together.

[0026] In step S2, a nozzle 14 having a neck 141, a curved shoulder 142, a bottom 143, a slanted body 144, and a through hole 145 is formed by machining, for example, using an aluminum material. At this time, it is preferable to anodize the surface of the nozzle 14 that is in contact with the overlapping portion 130 of the first divided body 111 (or opening divided body 114) (i.e., the surface of the slanted body 144). In addition to the surface of the slanted body 144, it is even more preferable to anodize the surface of the nozzle 14 that is in contact with the enclosure portion 120 of the first divided body 111 (or opening divided body 114) (i.e., the surface of the curved shoulder 142).

[0027] Step S3, which involves press-fitting the nozzle, corresponds to the "second step" described in the claims. In this step S3, for example, as shown in Figure 4, the nozzle formed in step S2 is press-fitted into the opening 13 of the first divided body 111 (or opening divided body 114) formed in step S1.

[0028] Step S4, in which the nozzle and liner are joined by heating, corresponds to the "third step" described in the claims. In step S4, the first divided body 111 (or the opening divided body 114) and the nozzle 14 are joined by heating the overlapping portion 130 of the first divided body 111 (or the opening divided body 114) from the inside of the first divided body 111 (or the opening divided body 114).

[0029] Specifically, as shown in Figure 5, for example, the first divided body 111 (or open divided body 114) with the nozzle 14 pressed into it is positioned so that the nozzle 14 is on the upper side and the first divided body 111 (or open divided body 114) is on the lower side. Next, the infrared-transparent member 20 is placed inside the first divided body 111 (or open divided body 114), and while the infrared-transparent member 20 holds the overlapping portion 130 of the first divided body 111 (or open divided body 114), the overlapping portion 130 is heated by the infrared heater 30 via the infrared-transparent member 20. In other words, in this step S4, the overlapping portion 130 is heated and pressed using the weight of the nozzle 14.

[0030] The infrared-transmitting member 20 is made of, for example, quartz glass and has a closed-bottom cylindrical shape to fit the shape of the overlapping portion 130 of the first divided body 111 (or opening divided body 114) and the bottom portion 143 of the nozzle 14. Specifically, the infrared-transmitting member 20 has a bottom plate portion 201 that holds the bottom surface of the bottom portion 143 of the nozzle 14 and the overlapping portion 130 of the first divided body 111 (or opening divided body 114), and a side wall portion 202 that holds the overlapping portion 130.

[0031] Furthermore, when heating with the infrared heater 30, it is preferable to heat at a temperature below the melting point of the resin material forming the liner 11. As shown in Figure 5, the infrared heater 30 is positioned near the side wall portion 202 of the infrared-transmitting member 20, and heats the overlapping portion 130 of the first divided body 111 (or open divided body 114) via the side wall portion 202. In order to ensure the quality of the liner 11, it is preferable not to heat any part of the first divided body 111 (or open divided body 114) other than the overlapping portion 130.

[0032] After heating for a predetermined time, the infrared heater 30 is removed from the first divided body 111 (or the open divided body 114), and then the infrared transparent member 20 is removed and taken away.

[0033] Step S5, which involves assembling the liner segments, corresponds to the "fourth step" described in the claims. In this step S5, the liner 11 is formed by assembling the liner segments. Specifically, if the liner 11 is composed of three liner segments, the first segment 111, which is joined to the end cap 14, is assembled to one end of the second segment 112, and the third segment 113 is assembled to the other end of the second segment 112 to form the liner 11. At that time, these liner segments are assembled so that the respective end portions of the first segment 111 and the third segment 113 are located outside the end of the second segment 112. Adhesive can be used when assembling these liner segments.

[0034] Furthermore, if the liner 11 is composed of two liner segments, the liner 11 is formed by assembling the open segment 114, which is joined to the nozzle 14, and the non-open segment 115. When assembling these liner segments, the end portion of the open segment 114 is positioned outside the end portion of the non-open segment 115. Adhesive can be used when assembling these liner segments.

[0035] In the resin reinforcement layer formation step S6, for example, a filament winding method (FW method) is used to wind a fiber bundle impregnated with resin so as to cover the outer surface of the liner 11 and a portion of the outer surface of the die 14, thereby forming the resin reinforcement layer 12.

[0036] The resin used to impregnate the fiber bundle is not particularly limited, but for example, a thermosetting resin can be used. Preferably, thermosetting resins such as phenolic resins, melamine resins, urea resins, and epoxy resins are used, and epoxy resins are particularly preferred from the viewpoint of mechanical strength, etc. Alternatively, a thermoplastic resin may be used as the resin impregnating the fiber bundle. Examples of thermoplastic resins include polyether ether ketone, polyphenylene sulfide, polyacrylic acid ester, polyimide, and polyamide.

[0037] The fibers that make up the fiber bundle can be glass fibers, aramid fibers, boron fibers, and carbon fibers, and in particular, carbon fibers are preferred from the viewpoint of weight reduction and mechanical strength.

[0038] Next, the wound resin reinforcement layer 12 is solidified (in other words, the resin of the fiber bundle is solidified). There are no particular limitations on the method of solidifying the resin reinforcement layer 12, but if the resin of the fiber bundle is made of a thermosetting resin, the resin of the fiber bundle is solidified by transporting it to a thermosetting furnace and heating it at a predetermined temperature and time. On the other hand, if the resin of the fiber bundle is made of a thermoplastic resin, the resin of the fiber bundle is solidified by cooling.

[0039] In the manufacturing method of the tank 10 according to this embodiment, two or more liner divisions, including a first division 111 (or opening division 114) with an opening 13, and a nozzle 14 are formed separately. Then, the nozzle 14 is press-fitted into the opening 13 of the first division 111 (or opening division 114). Compared to conventional insert molding, the quality of the liner division can be checked before press-fitting the nozzle 14. That is, before press-fitting the nozzle 14, the first division 111 (or opening division 114) is inspected for foreign matter, voids, etc., inside the first division 111 (or opening division 114) in its individual state, for example by X-ray. After the nozzle 14 is press-fitted using the first division 111 (or opening division 114) that has passed the quality inspection, it is joined by heating. As a result, even when the liner 11 and the nozzle 14 are made as a single unit, the quality of the liner 11 can be checked.

[0040] Furthermore, in step S4, the infrared-transparent member 20 is placed from the inside of the first divided body 111 (or the open divided body 114), and while the overlapping portion 130 is held by the infrared-transparent member 20, the overlapping portion 130 is heated by the infrared heater 30 via the infrared-transparent member 20. This allows the overlapping portion 130 to be heated while maintaining its shape with the infrared-transparent member 20.

[0041] Furthermore, by applying anodizing treatment to the surface of the beveled body portion 144 that contacts the overlapping portion 130 of the nozzle 14, it becomes possible to join the nozzle 14 and the first divided body 111 (or opening divided body 114) at a relatively low temperature. Therefore, even when heating at a temperature below the melting point of the resin material forming the liner 11, the nozzle 14 and the liner 11 can be joined. Moreover, since heating at a temperature below the melting point of the resin material forming the liner 11 has the effect of suppressing the sagging of the resin material.

[0042] [Examples] As described in step S4 above, the inventors of the present invention positioned the first divided body 111, into which the nozzle 14 was press-fitted, with the nozzle 14 on the upper side and the first divided body 111 on the lower side, and placed the infrared-transparent member 20 from the inside of the first divided body 111. The infrared-transparent member 20 held the overlapping portion 130 of the first divided body 111, and heated the overlapping portion 130 with an infrared heater 30 at the temperatures shown in Table 1 below, and evaluated the bonding strength at each temperature.

[0043] The first segment 111 was made of polyamide 6 (PA6) film, and the end cap 14 was made of aluminum. The surface of the beveled body 144 of the end cap 14 was anodized. The bonding strength was evaluated in accordance with the international standard ISO 19095 (Bonding Characteristics Evaluation Test). As shown in Table 1, the heating temperature was set lower than the melting point of PA6 (225°C) in all cases.

[0044] As can be seen from Table 1, using the bonding strength of the first divided body 111 and the end cap 14 at 80°C as a baseline, the bonding strength at 150°C was 1.3 times the baseline, and the bonding strength at 200°C was 1.5 times the baseline. This indicates that, under conditions where the heating temperature is below the melting point of the resin material forming the liner, the higher the heating temperature, the higher the bonding strength.

[0045] TIFF0007831426000001.tif35157

[0046] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. [Explanation of symbols]

[0047] 10: Tank, 11: Liner, 12: Resin reinforcement layer, 13: Opening, 14: Mouthpiece, 20: Infrared transparent member, 30: Infrared heater, 111: First segment, 112: Second segment, 113: Third segment, 114: Open segment, 115: Non-open segment, 120: Enclosure, 130: Overlapping section, 141: Neck, 142: Curved shoulder, 143: Bottom, 144: Sloping body, 145: Through hole, 201: Bottom plate, 202: Side wall

Claims

1. A method for manufacturing a tank comprising a resin liner having an opening and a metal nozzle pressed into the opening, A first step of forming two or more liner divisions, each including an opening division with the aforementioned opening, and the aforementioned end cap, A second step involves press-fitting the nozzle into the opening of the opening division body, A third step involves joining the opening division and the nozzle by heating the overlapping portion of the opening division with the nozzle from the inside of the opening division, A fourth step of forming the liner by assembling the two or more liner divisions, including the opening division, A method for manufacturing a tank, characterized by including [the necessary components].

2. The method for manufacturing a tank according to claim 1, wherein in the third step, an infrared-transparent member is placed from the inside of the opening division, and the overlapping portion of the opening division is held by the infrared-transparent member, and the overlapping portion of the opening division is heated with an infrared heater via the infrared-transparent member.

3. In the first step, anodizing treatment is applied to the surface of the opening division body in the nozzle that is in contact with the overlapping portion. The method for manufacturing a tank according to claim 1 or 2, wherein in the third step, the resin material forming the liner is heated at a temperature below its melting point.

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