Method for manufacturing a high-pressure tank

Abstract

Method for manufacturing a high-pressure tank (10) comprising a lining (11) configured for storing gas and a reinforcing layer made of a fiber-reinforced resin covering an outer surface of the lining (11), comprising: Forming a cylindrical element (21) made from the fiber-reinforced resin; Forming a pair of dome elements (22, 23) made from the fiber-reinforced resin; and Forming a reinforcing body (20), which is the reinforcing layer, by connecting circumferential edge sections (21b) of the cylindrical element (21) and circumferential edge sections (22c, 23a) of the dome elements (22, 23), wherein In forming the cylindrical element (21), a resin-impregnated fiber web (F2) is wound around an outer circumferential surface of a spindle (200) to form a cylindrical body (21a), and a resin-impregnated fiber bundle (F3) is then wound so that it overlaps the cylindrical body (21a).

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The invention relates to methods for manufacturing a high-pressure tank with a gas-storing lining and a reinforcing layer covering the outer surface of the lining made of a fiber-reinforced resin. 2. Description of the state of the art

[0002] A tank with a tank body and a projection or extension attached to one opening end in the longitudinal direction of the tank body is conventionally known as a high-pressure tank for storing and supplying hydrogen, etc. The tank body includes, for example, a lining for the airtight containment of hydrogen gas and a fiber-reinforced resin layer, which is formed by winding a bundle of fibers made of a fiber-reinforced resin around the outer surface of the lining to reinforce the lining.

[0003] In a known method for manufacturing a high-pressure tank, a fiber-reinforced resin layer is formed by wrapping a fiber bundle around the outer surface of a lining, e.g. by filament development (hereinafter also simply referred to as the "FW method"), and curing the fiber bundle.

[0004] In another known method for manufacturing a high-pressure tank, a resin-impregnated fiber web is wrapped around the outer surface of a lining to reduce the time required to form a fiber-reinforced resin layer (see, for example, Japanese patent application JP 2017 - 141 947 A).

[0005] In the method for manufacturing a tank described in JP 2017-141947A, the lining in the part around which the fiber web is to be wound has a smaller diameter than in the rest of the part. With this configuration, steps are less likely to form at both ends of a cylindrical section due to the thickness of the cylindrical section when the cylindrical section is formed by winding the fiber web around the lining. SUMMARY OF THE INVENTION

[0006] In the case where a cylindrical section is formed by winding a fiber web around a lining, as in JP 2017 - 141 947 A, the end of the winding of the fiber web may peel off after the fiber web has been wound.

[0007] The invention proposes a method for manufacturing a high-pressure tank that prevents the detachment of one end of the winding of a fiber web.

[0008] One aspect of the invention provides a method for manufacturing a high-pressure tank comprising a liner configured for gas storage and a reinforcing layer consisting of a fiber-reinforced resin covering an outer surface of the liner. This method comprises: forming a cylindrical element made of the fiber-reinforced resin; forming a pair of dome elements made of the fiber-reinforced resin; and forming a reinforcing body, which is the reinforcing layer, by joining circumferential edge sections of the cylindrical element and circumferential edge sections of the dome elements. In forming the cylindrical element, a resin-impregnated fiber web is wound around an outer circumferential surface of a spindle to form a cylindrical body, and a resin-impregnated fiber bundle is then wound to overlap the cylindrical body.

[0009] According to the inventive method, when forming the cylinder element, the resin-impregnated fiber web is wound around the outer circumferential surface of the spindle to form the cylinder body, and the resin-impregnated fiber bundle is then wound so that it overlaps the cylinder body. Accordingly, an outer circumferential surface of the cylinder body (fiber web) is held in place by the fiber bundle. This prevents the end of the fiber web winding from coming loose.

[0010] In the method described above, during the formation of the cylindrical element, after the cylinder body has been formed, the circumferential edge sections, which overlap the ends in an axial direction of the cylinder body, can be formed by winding the fiber bundle around the outer circumferential surface of the spindle such that the fiber bundle abuts both ends of the cylinder body. If the end of the fiber bundle winding detaches, the edges of the fiber web (the ends in the axial direction of the cylinder body) tend to detach first. Because the fiber bundle overlaps the edges of the fiber web, the end of the fiber web winding is effectively prevented from detaching. Even if the fiber bundle is wound so that, after the cylinder body has been formed, it abuts both ends of the cylinder body in an axial direction, the fiber bundle is still wound in such a way that it overlaps the ends of the cylinder body.The fiber core is wound in such a way that it is in close contact with the cylinder body. Therefore, it is less likely that cavities will form between the circumferential edge sections (fiber bundles) and the cylinder body. Since the circumferential edge sections of the cylinder element consist of the fiber bundle, they can also be designed to correspond to the circumferential edge sections of the dome elements.

[0011] In the method described above, if the fiber bundle is wound so that it abuts the two ends of the cylinder body in the axial direction, the cylinder element can be wound in such a way that it gradually becomes thinner as it extends away from the ends of the cylinder body. When joining the cylinder element and the dome elements, the circumferential edge sections of the cylinder element can be inserted and fitted into the circumferential edge sections of the dome elements, or the circumferential edge sections of the dome elements can be inserted and fitted into the circumferential edge sections of the cylinder element.Because the fiber bundle is wound in such a way that the cylindrical element gradually becomes thinner as it extends away from the ends of the cylinder body, steps are less likely to form in the connection sections between an outer surface of the cylindrical element and the outer surfaces of the dome elements when the cylindrical element and dome elements are joined. Accordingly, cavities are less likely to form between the outer reinforcing layer and the reinforcing body (the cylindrical element and the dome elements) due to steps in the connection sections between the cylindrical element and the dome elements if the outer reinforcing layer, such as a helical layer, is designed to cover the cylindrical element and the dome elements. The reduction in the high-pressure tank's strength due to cavities is thus prevented.

[0012] In the method described above, during the formation of the cylindrical element, after the cylinder body has been formed, the fiber bundle can be wound from one end of the cylinder body to the other end, overlapping the cylinder body. In this configuration, the outer circumferential surface of the cylinder body (fiber web) is held in place by the fiber bundle along its entire length in the axial direction of the cylinder body. This reliably prevents the end of the fiber web winding from coming loose.

[0013] In the method described above, when forming the cylindrical element, after the cylinder body has been formed, the circumferential edge section can be formed on one side by winding the fiber bundle around the outer circumferential surface of the spindle such that the fiber bundle abuts one end of the cylinder body. Alternatively, the fiber bundle can be wound from one end to the other end of the cylinder body, overlapping it. The circumferential edge section can also be formed on the other side by winding the fiber bundle around the outer circumferential surface of the spindle such that the fiber bundle abuts the other end of the cylinder body. In this configuration, the outer circumferential surface of the cylinder body (fiber web) is held in the axial direction of the cylinder body by the fiber bundle over both ends. This reliably prevents the end of the fiber tape winding from coming loose. Since the fiber bundle is continuous, or...Since the fiber bundle can be wound continuously from one area on one side to the other side of the cylinder body, the number of feed rollers for feeding the fiber bundle can also be reduced compared to the case where separate fiber bundles are wound around the area on one side of the cylinder body and the area on the other side of the cylinder body.

[0014] The invention thus provides a method for manufacturing a high-pressure tank that prevents the detachment of one end of the winding of a fiber bundle. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The features and advantages as well as the technical and economic significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which the same reference numerals denote the same elements, showing: Fig. 1 a sectional view showing the structure of a high-pressure tank manufactured according to a method according to a first embodiment of the invention; Fig. 2 a partial sectional view showing the structure of the high-pressure tank which is manufactured according to the method of the first embodiment of the invention; Fig. 3 a flowchart of the process for manufacturing a high-pressure tank according to the first embodiment of the invention; Fig. 4 a step to form a cylindrical element of the method for manufacturing a high-pressure tank according to the first embodiment of the invention; Fig. 5 the step to form the cylinder element of the method for manufacturing a high-pressure tank according to the first embodiment of the invention; Fig. 6 a sectional view illustrating the structure of circumferential edge sections of a cylindrical element; Fig. 7 a perspective view showing a connecting step of the method for manufacturing a high-pressure tank according to the first embodiment of the invention; Fig. 8 a sectional view showing a step in forming a lining of the method for manufacturing a high-pressure tank according to the first embodiment of the invention; Fig. 9 a sectional view showing the structure of a high-pressure tank manufactured according to a method according to a modification of the invention; Fig. 10 a step to form a cylindrical element of a method for manufacturing a high-pressure tank according to a second embodiment of the invention; and Fig. 11 a step to form a cylindrical element of a method for manufacturing a high-pressure tank according to a third embodiment of the invention. DETAILED DESCRIPTION OF EXECUTION FORMS (First embodiment)

[0016] Before describing a method for manufacturing a high-pressure tank 10 according to a first embodiment of the invention, the construction of the high-pressure tank 10 is briefly described with reference to the drawings. Although the high-pressure tank 10 is described here as a tank mounted on a fuel cell vehicle and filled with high-pressure hydrogen gas, the high-pressure tank 10 can also be used in other applications. The gas that can be used for the high-pressure tank 10 is not limited to high-pressure hydrogen gas.

[0017] As in the Fig. 1 and Fig. As shown in Figure 2, the high-pressure tank 10 is a generally cylindrical high-pressure gas storage vessel with domed ends. The high-pressure tank 10 comprises a lining 11 with gas barrier properties and a fiber-reinforced resin layer 12, which consists of a fiber-reinforced resin and covers the outer surface of the lining 11. The fiber-reinforced resin layer 12 has a reinforcing body 20 and an outer reinforcing layer 13. The reinforcing body 20 is a reinforcing layer and covers the outer surface of the lining 11, and the outer reinforcing layer 13 covers the outer surface of the reinforcing body 20. The high-pressure tank 10 has an opening at one end and a projection or protrusion 14 surrounding the opening. The high-pressure tank 10 has no opening or protrusion at the other end.

[0018] The lining 11 extends along the inner surface of the reinforcement body 20. The lining 11 is a resin element that forms a storage chamber 17 filled with high-pressure hydrogen gas. The resin for the lining 11 is preferably a resin capable of retaining the filling gas (in this example, hydrogen gas) in the storage chamber 17, namely a resin with satisfactory gas barrier properties. Examples of such a resin are thermoplastic resins such as polyamide, polyethylene, ethylene-vinyl alcohol copolymer (EVOH), and polyester, as well as thermosetting resins such as epoxy resin. Instead of hydrogen gas, the lining 11 can also be filled with other fuel gases. Examples of fuel gases are compressed gases such as compressed natural gas (CNG) and various liquefied gases such as liquefied natural gas (LNG) and liquefied petroleum gas (LPG).

[0019] The attachment 14 is formed into a predetermined shape by machining a metal material such as aluminum or an aluminum alloy. A valve 15, which controls the flow of hydrogen gas into and out of the storage chamber 17, is attached to the attachment 14. The valve 15 is provided with a sealing element 15a. The sealing element 15a rests against the inner surface of the lining 11 in a projecting section 22a of a dome element 22 described later and seals the storage chamber 17 of the high-pressure tank 10.

[0020] The reinforcing body 20 covers the outer surface of the lining 11 and serves to strengthen the lining 11 in order to improve the mechanical strength, such as stiffness and pressure resistance, of the high-pressure tank 10. As described later, the reinforcing body 20 has a cylindrical cylinder element 21 and a pair of coupling elements 22, 23 connected to both ends of the cylindrical element 21. The reinforcing body 20 is formed by connecting the cylindrical element 21 and the coupling elements 22, 23. In the present embodiment, the cylindrical element 21 consists of a cylindrical cylinder body 21a and circumferential edge sections 21b that contact both ends of the cylindrical body 21a.

[0021] The reinforcing body 20 is made of resin and fibers (continuous fibers). In the cylindrical element 21, the fibers extend along the circumference of the cylindrical element 21 at an angle that is essentially perpendicular to the axial direction X of the reinforcing body 20. In other words, the fibers in the cylindrical element 21 are oriented in the circumferential direction of the cylindrical element 21. The fibers are wrapped at least once around the outer surface of the lining 11. In the dome elements 22, 23, however, the fibers are not oriented in the circumferential direction of the cylindrical element 21, but rather the fibers, which extend in different directions intersecting the circumferential direction, are arranged one above the other.

[0022] The outer reinforcing layer 13 covers the outer surface of the reinforcing body 20. The outer reinforcing layer 13 is made of resin and fibers (continuous fibers). In the outer reinforcing layer 13, the fibers are oriented parallel or obliquely at an angle of 45 degrees or less to the axial direction X of the cylindrical element 21 and extend over the cylindrical element 21 and over the dome elements 22, 23 located at both ends of the cylindrical element 21. These fibers prevent the dome elements 22, 23 from moving outwards in the axial direction X and thus prevent the dome elements 22, 23 from detaching from the cylindrical element 21 due to gas pressure in the axial direction X.

[0023] Next, a method for manufacturing the high-pressure tank 10 according to the first embodiment of the invention is described. Fig. Figure 3 is a flowchart of the process for manufacturing the high-pressure tank 10. As in Fig. As shown in Figure 3, the method for manufacturing the high-pressure tank 10 comprises a step S1 for forming a dome element (dome element formation step), a step S2 for forming a cylinder element (cylinder element formation step), a joining step S3, a step S4 for forming an outer reinforcing layer (outer reinforcing layer formation step), and a step S5 for forming a lining (lining formation step). Since step S1 for forming the dome element and step S2 for forming the cylinder element are independent of each other, steps S1 and S2 can be performed either in parallel or sequentially in any order.

[0024] In step S1 of the dome element formation process, the dome elements 22 and 23 are formed from a fiber-reinforced resin. The dome elements 22 and 23 can be formed, for example, by attaching (or winding) a resin-impregnated fiber bundle around a mold with a dome-shaped surface and curing the fiber bundle, or by injection molding. At this stage, the cylindrical, projecting section 22a with a through-hole 22b is formed in the dome element 22. The projection 14 is attached to the outer surface of the projecting section 22a of the dome element 22.

[0025] The resin with which the fiber bundle is impregnated is not particularly restricted; for example, it can be a thermosetting or heat-curing resin. Preferred examples of the thermosetting resin are a phenolic resin, a melamine resin, a urea resin, and an epoxy resin, with an epoxy resin being particularly preferred with respect to mechanical strength, etc. Epoxy resins are typically resins produced by mixing a prepolymer, such as a copolymer of bisphenol A and epichlorohydrin, and a curing agent, such as a polyamine, and then thermally curing the mixture. Epoxy resins are liquid in the uncured state and form a highly cross-linked structure upon thermal curing. The resin with which the fiber bundle is impregnated can be a thermoplastic resin. Examples of thermoplastic resins are polyetheretherketone, polyphenylene sulfide, polyacrylic acid esters, polyimide, and polyamide.

[0026] Examples of fibers in the fiber bundle include glass fibers, aramid fibers, boron fibers, and carbon fibers. Carbon fibers are particularly preferred due to their lightness, mechanical strength, etc.

[0027] In step S2 for forming the cylindrical element, as in the Fig. 4 and Fig. As shown in Figure 5, the cylindrical element 21 is formed using both web winding and filament development. In web winding, a fiber web F2 is wound around the outer circumferential surface of a rotating solid or hollow cylindrical spindle 200. In filament development, a fiber bundle F3 is wound around the outer circumferential surface of the spindle 200.

[0028] In particular, the spindle 200 has a shaft 201, and the shaft 201 is rotated at a predetermined speed by a shaft drive mechanism (not shown). The material of the spindle 200 is not particularly limited, but is preferably made of metal so that the spindle 200 is strong enough not to deform when the fiber web F2 is attached to the spindle 200.

[0029] A web feeder and a fiber bundle feeder are arranged such that they face the outer circumferential surface of the spindle 200. The web feeder comprises a feed roller 210 (see Fig. 4), which feeds the fiber web F2 to the spindle 200. The fiber bundle feeder includes feed rollers 220 (see Fig. 5) which feed the fiber bundle F3 to the spindle 200. The feed roller 210 is rotatable at a predetermined speed. The feed rollers 220 are rotatable at a predetermined speed and movable in the axial direction of the shaft 201. In the present embodiment, the two feed rollers 220 are arranged such that they face both ends of the spindle 200. As described later, in the present embodiment, the fiber bundle F3 is wound up using the feed rollers 220 after the fiber web F2 has been wound up using the feed roller 210.

[0030] The fiber web F2 has at least fibers oriented in the circumferential direction of the feed roller 210, and the fiber bundle F3 is formed by fibers oriented in the circumferential direction of the feed roller 220. Thus, the cylindrical element 21 can be produced with circumferentially oriented fibers.

[0031] Examples of the fiber web F2 include a unidirectional (UD) web formed by interlacing a plurality of fiber bundles oriented in a single direction with a retaining thread, and a fiber web formed by interlacing a plurality of fiber bundles oriented in a single direction with a plurality of fiber bundles that cross these fiber bundles, e.g., oriented perpendicular to these fiber bundles. The fiber web F2 is pre-impregnated with resin. The fiber bundle F3 is also pre-impregnated with resin.

[0032] The resin with which the fiber web F2 and the fiber bundle F3 are impregnated is not particularly restricted, but is, for example, a thermosetting resin. Like the fiber bundle for the dome elements 22, 23, preferred examples of the thermosetting resin include a phenolic resin, a melamine resin, a urea resin, and an epoxy resin, with an epoxy resin being particularly preferred with respect to mechanical strength, etc.

[0033] Like the fiber bundle for the dome elements 22, 23, examples of the fibers of the fiber web F2 and the fiber bundle F3 include glass fibers, aramid fibers, boron fibers and carbon fibers, with carbon fibers being particularly preferred with regard to lightness, mechanical strength, etc.

[0034] As in Fig. As shown in Figure 4, the fiber web F2 is fed from the feed roller 210 while the spindle 200 rotates. The fiber web F2 is thus wound around a predetermined section of the spindle 200. Once a predetermined length of the fiber web F2 has been wound around the spindle 200, the fiber web F2 is cut at a predetermined position. In this way, the cylindrical body 21a is formed from the fiber web F2.

[0035] Next, as in Fig. As shown in Figure 5, the fiber bundle F3 is fed by the two feed rollers 220 while the spindle 200 rotates. The fiber bundle F3 is thus wound around two regions of the outer circumferential surface of the spindle 200, namely a region adjacent to one end of the cylinder body 21a and a region adjacent to the other end of the cylinder body 21a. During winding, the feed rollers 220 are moved axially along the spindle 200, so that the fiber bundle F3 is wound in a predetermined shape in the region on one side of the cylinder body 21a and the region on the other side of the cylinder body 21a. The circumferential edge sections 21b are formed in this way. In particular, the fiber bundle F3 is wound such that the cylinder element 21 gradually becomes thinner as it extends away from the ends of the cylinder body 21a.The outer circumferential surface of the cylindrical body 21a (fiber web F2) and the outer circumferential surface of the spindle 200 are thus connected via the inclined surfaces formed by the fiber bundle F3. The circumferential edge sections 21b of the cylindrical element 21 are designed such that the outer circumferential surfaces of the circumferential edge sections 21b coincide with the inner surface of a circumferential edge section 22c of the dome element 22 and the inner surface of a circumferential edge section 23a of the dome element 23. It is therefore less likely that the cylindrical element 21 will detach from the dome elements 22, 23.

[0036] When forming the circumferential edge sections 21b, the fiber bundle F3 is wound so that it closely touches the cylindrical body 21a (fiber web F2) and is also wound at least once around the edges on one side and the other side of the cylindrical body 21a (fiber web F2) so that it overlaps these edges of the cylindrical body 21a (fiber web F2) (see Fig. 6) The edges on both sides of the cylindrical body 21a (fiber web F2) are thus held in place by the fiber bundle F3. This prevents the fiber material F2 from detaching.

[0037] Once the circumferential edge sections 21b have been formed on both sides in the axial direction of the cylinder body 21a, the fiber bundle F3 is cut at a predetermined position, and the winding of the fiber bundle F3 around the spindle 200 is complete. The cylinder element 21 (the cylinder body 21a and the circumferential edge sections 21b) is then cured and removed from the spindle 200. Step S2 for forming the cylinder element is thus completed.

[0038] As described above, in step S2 of forming the cylinder element, the resin-impregnated fiber web F2 is wound around the outer circumferential surface of the spindle 200, and the resin-impregnated fiber bundle F3 is then wound so that it overlaps the cylinder body 21a. The outer circumferential surface of the cylinder body 21a (fiber web F2) is thus held in place by the fiber bundle F3, and one end Fa of the winding of the fiber web F2 is prevented from unwinding. If the end Fa of the winding of the fiber web F2 were to unwind, the edges of the fiber web F2 (the ends in the axial direction X of the cylinder body 21a) would tend to unwind first. Since the fiber bundle F3 overlaps the edges of the fiber web F2, the end Fa of the winding of the fiber web F2 is effectively prevented from unwinding.

[0039] As described above, the cylindrical element 21 is designed such that its two ends gradually taper in the axial direction. As in Fig. As shown in Figure 1, steps are therefore less likely to form in the connection sections between the outer surface of the cylindrical element 21 (the outer circumferential surface of the cylindrical body 21a) and the outer surfaces of the dome elements 22, 23 when the cylindrical element 21 is inserted and fitted into the dome elements 22, 23, as described below. Accordingly, cavities are less likely to form between the outer reinforcing layer 13 and the reinforcing body 20 (the cylindrical element 21 and the dome elements 22, 23) due to steps in the connection sections between the cylindrical element 21 and the dome elements 22, 23, if the outer reinforcing layer 13, such as a helical layer, is designed to cover the cylindrical element 21 and the dome elements 22, 23, as described below. A reduction in the strength of the high-pressure tank 10 due to cavities is thus prevented.

[0040] As described above, the cylindrical element 21 is formed using the spindle 200. In other words, the cylindrical element 21 is formed without the fiber bundle, etc., being directly wound around the lining 11. Since the lining 11 is not subjected to any tension caused by winding the web, it is not necessary to increase the thickness of the lining 11 to prevent deformation due to tension. Therefore, it is possible to reduce the thickness (wall thickness) of the lining 11. Consequently, the capacity of the lining 11 can be increased and its weight reduced.

[0041] In the example above, the fiber bundle F3 is wound simultaneously using both feed rollers 220. However, for example, only one feed roller 220 can be used, and the circumferential edge sections 21b can be formed separately on both sides of the cylinder body 21a in the axial direction using this feed roller 220. In the example above, the circumferential edge sections 21b are formed to have an inclined outer surface. However, the circumferential edge sections 21b can also be formed to have a stepped outer surface. More precisely, the circumferential edge sections 21b can be formed such that the cylinder element 21 becomes progressively thinner as it extends away from the ends of the cylinder body 21a.

[0042] In connection step S3, as in Fig. Figure 7 shows the circumferential edge sections 21b at both ends of the cylindrical element 21 and the circumferential edge sections 22c, 23a of the dome elements 22, 23 (see Fig. 1) connected to form the reinforcing body 20, which is a reinforcing layer.

[0043] Specifically, either the circumferential edge sections 21b of the cylindrical element 21 or the circumferential edge sections 22c, 23a of the dome elements 22, 23 (in this example, the circumferential edge sections 21b) are inserted into and fitted into the other element (in this example, the circumferential edge sections 22c, 23a). At this point, an adhesive (not shown) can be applied between the cylindrical element 21 and the dome elements 22, 23. This configuration prevents the dome elements 22, 23 from detaching from the cylindrical element 21 in a later step. Since the adhesive fills the spaces between the cylindrical element 21 and the dome elements 22, 23, it also prevents a resin material for the lining 11 from flowing into the spaces between the cylindrical element 21 and the dome elements 22, 23 in step S5 to form the lining. The material of the adhesive is not particularly limited, but is preferably, e.g.a thermosetting resin such as epoxy resin.

[0044] In step S4, the formation of the outer reinforcement layer, the outer reinforcement layer 13, which consists of a fiber-reinforced resin and has fibers laid over the dome elements 22, 23, is formed such that it covers the outer surface of the reinforcement body 20. The fiber-reinforced resin layer 12 with the reinforcement body 20 and the outer reinforcement layer 13 is formed in this way. The outer reinforcement layer 13 can be formed, for example, by spirally winding a plurality of resin-impregnated fiber bundles around the outer surface of the reinforcement body 20. Alternatively, the outer reinforcement layer 13 can be formed by attaching a plurality of resin-impregnated fiber bundles to the outer surface of the reinforcement body 20, such that the resin-impregnated fiber bundles extend in the axial direction X of the reinforcement body 20.The outer reinforcement layer 13 can be formed by winding a resin-impregnated fiber web around the outer surface of the reinforcement body 20 by web winding.

[0045] The resin with which the fiber bundles are impregnated is not particularly restricted, but is, for example, a thermosetting resin. Like the fiber bundle for the dome elements 22, 23, preferred examples of the thermosetting resin include a phenolic resin, a melamine resin, a urea resin, and an epoxy resin, with an epoxy resin being particularly preferred with respect to mechanical strength, etc.

[0046] Like the fiber bundle for the dome elements 22, 23, examples of the fibers of the fiber bundles include glass fibers, aramid fibers, boron fibers and carbon fibers, with carbon fibers being particularly preferred with regard to lightness, mechanical strength, etc.

[0047] As described above, the outer reinforcing layer 13 has fibers arranged over the dome elements 22, 23. The fibers of the outer reinforcing layer 13 therefore prevent the dome elements 22, 23 from separating from the cylinder element 21. The dome elements 22, 23 are thus prevented from detaching from both ends of the cylinder element 21 due to gas pressure.

[0048] In step S5 for forming the lining, as in Fig. As shown in Figure 8, a resin material M is introduced into the fiber-reinforced resin layer 12 through the through-hole 22b in the preceding section 22a of the reinforcement body 20. The resin material M is then solidified while the fiber-reinforced resin layer 12 rotates. In this way, the lining 11 is formed.

[0049] In particular, the interior of the fiber-reinforced resin layer 12 is connected to the space outside the fiber-reinforced resin layer 12 via the through-hole 22b. A nozzle 500, which ejects the resin material M, is inserted through the through-hole 22b, and the resin material M is introduced into the interior of the fiber-reinforced resin layer 12 through the nozzle 500. The nozzle 500 is then removed from the through-hole 22b.

[0050] As described above, the resin material M is preferably a resin with satisfactory gas barrier properties. Examples of such a resin are thermoplastic resins such as polyamide, polyethylene, ethylene-vinyl alcohol copolymer (EVOH) resin, and polyester, as well as thermosetting resins such as epoxy resin, with polyamide being preferred.

[0051] The interior of the fiber-reinforced resin layer 12 is then heated to a predetermined temperature or higher, as required. Since the resin material has a low viscosity and is liquid, the fiber-reinforced resin layer 12 is rotated circumferentially around its horizontal axis while both ends of the fiber-reinforced resin layer 12 are alternately moved up and down (see Fig. 8) When the fiber-reinforced resin layer 12 is rotated, the inner surface of the fiber-reinforced resin layer 12, with the liquid resin material M on it, moves upwards, and some of the resin material M flows down the inner surface of the fiber-reinforced resin layer 12 due to its own weight. The resin material M thus covers the entire inner surface of the reinforcement body 20. If the resin material M is a thermosetting or thermoset resin, the interior of the fiber-reinforced resin layer 12 is heated to cure the resin material M. This forms the lining 11. If the resin material M is a thermoplastic resin, the interior of the fiber-reinforced resin layer 12 is cooled to solidify the resin material M that is in contact with and covers the inner surface of the fiber-reinforced resin layer 12. This forms the lining 11.In this example, the lining 11 is formed by reaction injection molding using two or more types of low molecular weight, low viscosity liquid materials that are liquid at room temperature as the resin material M. In this case, the interior of the fiber-reinforced resin layer 12 is heated to produce a polymer from a monomer. Subsequently, the interior of the fiber-reinforced resin layer 12 is cooled to solidify the polymer, thereby forming the lining 11.

[0052] According to step S5 for forming the lining, the lining 11 can easily be formed within the fiber-reinforced resin layer 12, even after the fiber-reinforced resin layer 12 has formed. Furthermore, unlike the case where the lining is formed by injection molding with resin, no mold is required to form the lining.

[0053] The high-pressure tank 10 is completed by attaching the valve 15 to the connection 14.

[0054] As described above, in step S2 of forming the cylinder element of the present embodiment, the resin-impregnated fiber web F2 is wound around the outer circumferential surface of the spindle 200, and the resin-impregnated fiber bundle F3 is then wound so that it overlaps the cylinder body 21a. The outer circumferential surface of the cylinder body 21a (fiber web F2) is thus held by the fiber bundle F3, and the end Fa of the winding of the fiber web F2 is prevented from unwinding. If the end Fa of the winding of the fiber web F2 were to unwind, the edges of the fiber web F2 (the ends in the axial direction X of the cylinder body 21a) would tend to unwind first. Since the fiber bundle F3 overlaps the edges of the fiber web F2, the end Fa of the winding of the fiber web F2 is effectively prevented from unwinding.

[0055] In the example described in the present embodiment, the cylindrical element 21 is inserted and fitted into the dome elements 22, 23. However, for example, as in a Fig. In the modification shown in Figure 9, the dome elements 22, 23 are inserted into the cylindrical element 21 such that the circumferential edge sections 22c, 23a of the dome elements 22, 23 are fitted into the circumferential edge sections 21b of the cylindrical element 21. In this case as well, it is less likely that steps will form in the connecting sections between the outer surface of the cylindrical element 21 (the outer surface of the cylindrical body 21a) and the outer surfaces of the dome elements 22, 23. Accordingly, it is less likely that cavities will form between the outer reinforcing layer 13 and the reinforcing body 20 due to the steps in the connecting sections between the cylindrical element 21 and the dome elements 22, 23 if the outer reinforcing layer 13 is designed to cover the cylindrical element 21 and the dome elements 22, 23. This prevents the reduction in the strength of the high-pressure tank 10 due to cavities. (Second embodiment)

[0056] A second embodiment is described by way of an example in which, unlike the first embodiment, the fiber bundle F3 is wound around the outer circumferential surface of the cylindrical body 21a (fiber web F2) in step S2 to form the cylindrical element. In the present embodiment, the cylindrical element 21 is formed by the cylindrical body 21a, and the two ends in the axial direction of the cylindrical body 21a are the circumferential edge sections of the cylindrical element 21.

[0057] In the second embodiment, as in Fig. Figure 10 shows a feed roller 220 arranged such that it faces the outer circumferential surface of the spindle 200.

[0058] In step S2 for forming the cylinder element, the fiber web F2 is first wound around a predetermined area of ​​the spindle 200, as in the first embodiment. In this way, the cylinder body 21a is formed from the fiber material F2.

[0059] Next, as in Fig. Figure 10 shows the fiber bundle F3 being fed from the feed roller 220 while the spindle 200 rotates. The fiber bundle F3 is thus wound around the outer circumferential surface of the cylinder body 21a (fiber web F2). The feed roller 220 is moved axially along the shaft 201 during the feeding of the fiber bundle F3. The fiber bundle F3 is thus wound from one end to the other of the cylinder body 21a (fiber web F2). At this point, the fiber bundle F3 is wound axially at a predetermined distance or angle (so that the fiber web F2 is exposed).

[0060] Once the fiber bundle F3 has been wound from one end to the other of the cylinder body 21a (fiber web F2), the fiber bundle F3 is cut at a predetermined position, and the winding of the fiber bundle F3 is complete. The cylinder element 21 (the cylinder body 21a and the circumferential edge sections 21b) is then cured and removed from the spindle 200. Step S2 for forming the cylinder element is thus completed.

[0061] The construction of the high-pressure tank 10 and the method for manufacturing the high-pressure tank 10 according to the present embodiment are otherwise similar to those of the first embodiment.

[0062] In the present embodiment, as described above, the fiber bundle F3 is wound from one end to the other of the cylinder body 21a (fiber web F2) so that it overlaps the cylinder body 21a. The outer circumferential surface of the cylinder body 21a is thus held by the fiber bundle F3 over its entire length in the axial direction X of the cylinder body 21a. The end Fa of the winding of the fiber web F2 is thus reliably prevented from coming loose.

[0063] Other effects of the present embodiment are similar to those of the first embodiment. (Third embodiment)

[0064] A third embodiment is described in reference to an example in which, in contrast to the first and second embodiments, the fiber bundle F3 is wound around two areas of the outer circumferential surface of the spindle 200 in step S2 to form the cylinder element, namely around an area adjacent to one end of the cylinder body 21a and around an area adjacent to the other end of the cylinder body 21a, and around the outer circumferential surface of the cylinder body 21a.

[0065] In the third embodiment, as in Fig. Figure 11 shows a feed roller 220 arranged such that it faces the outer circumferential surface of the spindle 200.

[0066] In step S2 for forming the cylinder element, the fiber web F2 is first wound around a predetermined area of ​​the spindle 200, as in the first embodiment. In this way, the cylinder body 21a is formed from the fiber material F2.

[0067] Next, as in Fig. Figure 11 shows the fiber bundle F3 being fed from the feed roller 220 while the spindle 200 rotates. The fiber bundle F3 is wound around the region of the outer circumferential surface of the spindle 200 that adjoins one end of the cylinder body 21a. In this way, the circumferential edge section 21b is formed on one side. Since the feed roller 220 is moved in the axial direction, the fiber bundle F3 is wound such that the cylinder element 21 gradually becomes thinner as it extends away from one end of the cylinder body 21a, as in the first embodiment.

[0068] When the winding of the fiber bundle F3 around the area on one side of the cylinder body 21a is complete, the feed roller 220 is then moved to the other side in the axial direction of the shaft 201 while the fiber bundle F3 is fed in. The fiber bundle F3 is thus wound around the outer circumferential surface of the cylinder body 21a (fiber web F2). As in Fig. As shown in Figure 11, the fiber bundle F3 is wound in the axial direction at a predetermined distance or angle of attack (so that the fiber web F2 is exposed).

[0069] As the fiber bundle F3 is fed in, the feed roller 220 is moved further in the axial direction to the other side. The fiber bundle F3 is thus wound around the region of the outer circumferential surface of the spindle 200 that adjoins the other end of the cylinder body 21a. This forms the circumferential edge section 21b on the other side. Since the feed roller 220 is moved in the axial direction, the fiber bundle F3 is wound such that the cylinder element 21 gradually becomes thinner as it extends away from the other end of the cylinder body 21a, as in the first embodiment.

[0070] Once the circumferential edge section 21b has formed on the other side of the cylinder body 21a, the fiber bundle F3 is cut at a predetermined position, and the winding of the fiber bundle F3 around the spindle 200 is complete. The cylinder element 21 (the cylinder body 21a and the circumferential edge sections 21b) is then cured and removed from the spindle 200. Step S2 for forming the cylinder element is thus completed.

[0071] The construction of the high-pressure tank 10 and the method for manufacturing the high-pressure tank 10 according to the present embodiment are otherwise similar to those of the first embodiment. In forming the circumferential edge sections 21b, the fiber bundle F3 can be wound at least once around the edges of the cylinder body 21a, so that it overlaps the edges of the cylinder body 21a as in the first embodiment. The circumferential edge sections 21b do not need to overlap the edges of the cylinder body 21a.

[0072] As described above, in the present embodiment the fiber bundle F3 is wound onto the outer circumferential surface of the cylinder body 21a (fiber web F2) as it is moved from the area on one side of the cylinder body 21a to the area on the other side of the cylinder body 21a. The outer circumferential surface of the cylinder body 21a is thus held by the fiber bundle F3 over its entire length in the axial direction X of the cylinder body 21a. The end Fa of the winding of the fiber web F2 is thus reliably prevented from coming loose.Since the fiber bundle F3 can be continuously wound from the area on one side of the cylinder body 21a to the area on the other side of the cylinder body 21a, the number of feed rollers 220 for feeding the fiber bundle F3 can also be reduced compared to the case where separate fiber bundles F3 are wound around the area on one side of the cylinder body 21a and the area on the other side of the cylinder body 21a.

[0073] In the example described in the present embodiment, the fiber bundle F3 is continuously wound around the area on one side of the cylinder body 21a, the outer circumferential surface of the cylinder body 21a, and the area on the other side of the cylinder body 21a. The fiber bundle F3 can be cut each time the winding around each area is completed. In other words, the winding around each area can be performed separately. Alternatively, the winding around each area can be performed simultaneously using two or more feed rollers 220.

[0074] Other effects of the present embodiment are similar to those of the first embodiment.

[0075] The embodiments disclosed herein are to be understood in every respect as illustrative and not limiting. The scope of the invention is shown by the claims and not by the description of the embodiments and includes all modifications that are made without deviation from the idea and scope of the claims.

[0076] For example, in the embodiment described above, the lining is formed after the reinforcement body and the outer reinforcement layer have been formed. However, the invention is not limited to this. If, for example, both ends of the cylindrical element and the circumferential edge sections of the dome elements are combined in the joining step, the cylindrical element and the dome elements can be joined in such a way that they cover a previously formed resin lining. In this case, the step for forming the lining is not carried out. Such a lining can be formed by a conventionally known manufacturing process. However, the lining does not need to have high strength, since no fiber bundle is wound around the outer surface of the lining in the FW process. Accordingly, the thickness of the lining can be reduced compared to conventional linings.The lining can be made of a metallic material such as an aluminum alloy instead of the resin material.

[0077] In the example described in the embodiment above, the reinforcing body consists of three elements (the cylindrical element and the pair of dome elements). However, the invention is not limited to this. For example, the reinforcing body can be composed of four or more elements (two or more cylindrical elements and a pair of dome elements). In this case, the two or more cylindrical elements can first be joined together to form a single cylindrical element, and the dome elements can then be connected to both ends of the cylindrical element. Alternatively, the cylindrical elements can first be connected to the dome elements, one to each dome element, and the resulting elements can then be joined together.

[0078] In the example described in the embodiment above, the lining is formed on the outer surface of the reinforcement body after the outer reinforcing layer has been formed. However, the invention is not limited to this. The outer reinforcing layer can also be formed on the outer surface of the reinforcement body after the lining has been formed inside the body. In this case, the lining is preferably formed using a thermosetting resin, such as epoxy resin, so that the lining does not soften during the curing of the outer reinforcing layer.

[0079] In the example described in the embodiment above, the circumferential edge sections are designed to have an inclined outer surface (or stepped outer surface). However, the outer surfaces of the circumferential edge sections can also be other than inclined (or stepped) outer surfaces.

Claims

[1] A method for manufacturing a high-pressure tank (10) comprising a liner (11) configured to store gas and a reinforcing layer made of a fiber-reinforced resin and covering an outer surface of the liner (11), comprising: Forming a cylinder member (21) made of the fiber-reinforced resin; forming a pair of dome elements (22, 23) made of the fiber-reinforced resin; and Forming a reinforcing body (20), which is the reinforcing layer, by connecting peripheral edge portions (21b) of the cylinder element (21) and peripheral edge portions (22c, 23a) of the dome elements (22, 23), wherein in forming the cylinder member (21), a resin-impregnated fiber web (F2) is wound around an outer peripheral surface of a spindle (200) to form a cylinder body (21a), and a resin-impregnated fiber bundle (F3) is then wound so as to overlap the cylinder body (21a). [2] The method according to claim 1, wherein in forming the cylinder member (21), after forming the cylinder body (21a), the peripheral edge portions (21b) overlapping ends in an axial direction of the cylinder body (21a) are formed by winding the fiber bundle (F3) around the outer peripheral surface of the spindle (200) such that the fiber bundle (F3) is adjacent to the two ends of the cylinder body (21a). [3] Method according to claim 2, wherein when winding the fiber bundle (F3) such that the fiber bundle (F3) is adjacent to the two ends in the axial direction of the cylinder body (21a), the fiber bundle (F3) is wound such that the cylinder element (21) gradually becomes thinner as the cylinder element (21) extends away from the ends of the cylinder body (21a), and when connecting the cylinder element (21) and the coupling elements (22, 23), the peripheral edge sections (21b) of the cylinder element (21) are inserted and fitted into the peripheral edge sections (22c, 23a) of the coupling elements (22, 23) or the peripheral edge sections (22c, 23a) of the coupling elements (22, 23) are inserted and fitted into the peripheral edge sections (21b) of the cylinder element (21). [4] Method according to one of claims 1 to 3, wherein when forming the cylinder element (21), after forming the cylinder body (21a), the fiber bundle (F3) is wound from one end of the cylinder body (21a) to the other end of the cylinder body (21a) so as to overlap the cylinder body (21a). [5] The method according to claim 1, wherein in forming the cylinder member (21), after forming the cylinder body (21a), the peripheral edge portion (21b) is formed on one side by winding the fiber bundle (F3) around the outer peripheral surface of the spindle (200) such that the fiber bundle (F3) is adjacent to one end of the cylinder body (21a), the fiber bundle (F3) is wound from one end to the other end of the cylinder body (21a) so as to overlap the cylinder body (21a), and the peripheral edge portion (21b) is formed on the other side by winding the fiber bundle (F3) around the outer peripheral surface of the spindle (200) such that the fiber bundle (F3) is adjacent to the other end of the cylinder body (21a).

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