Cans and their manufacturing methods

Abstract

The present invention provides a can and a method for manufacturing the same, which can prevent fiber displacement during resin injection and suppress strength reduction. The can is configured such that resin (18) is impregnated on a fiber layer (17) formed by overlapping a braided layer (17E) with a spiral layer (17A). The spiral layer (17A) is formed by spirally winding fibers (16) around the outer surface of a liner (12). The braided layer (17E) is formed by winding the fibers (16) in an interlaced manner with larger fiber spacing compared to the spiral layer (17A).

Description

Technical Field

[0001] This invention relates to a fiber-reinforced (strengthened) can and a method for manufacturing the same. Background Technology

[0002] Patent Document 1 discloses a method for manufacturing an FRP can (hereinafter also referred to as a high-pressure can). In this manufacturing method, after performing a covering process in which fibers are wound around an inner liner for covering, an impregnation process is performed in which resin is impregnated into the fibers. Afterward, the resin-impregnated fibers are heated to cure the resin.

[0003] Furthermore, Patent Document 2 discloses a high-pressure tank (pressure vessel) manufactured using this RTM (Resin Transfer Molding) method. This high-pressure tank (pressure vessel) comprises: a container body having a cylindrical straight section and domes integrally formed at both ends of the straight section, each dome including a hemispherical portion; a first reinforcing section formed by winding reinforcing fibers in an interlaced braid around the outer peripheral surface of one of the domes; a second reinforcing section formed by continuously winding the reinforcing fibers from the first reinforcing section in a spiral pattern around the outer peripheral surface of the straight section; and a third reinforcing section formed by continuously winding the reinforcing fibers from the second reinforcing section in an interlaced braid around the outer peripheral surface of the other dome.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-085199

[0007] Patent Document 2: Japanese Patent Application Publication No. 2020-026817 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] In the aforementioned manufacturing method using the RTM method, the fiber winding process and the resin impregnation process are performed separately when manufacturing the high-pressure tank. However, during resin injection, there is a possibility that the fibers in the straight sections may shift, resulting in a decrease in strength.

[0010] The present invention was made in view of the above circumstances, and its object is to provide a can and a method thereof capable of preventing fiber displacement during resin injection and suppressing strength reduction.

[0011] Technical solutions for solving the problem

[0012] To achieve the above objectives, one aspect of the present invention is a can having a reinforcing layer formed by impregnating a fiber layer with resin. The fiber layer is formed by radially overlapping and winding fibers onto the outer surface of a hollow liner having a cylindrical straight body and a dome that gradually narrows from the axial end of the straight body toward the side opposite to the straight body. The can is characterized in that the resin is impregnated onto the fiber layer, which is formed by overlapping a braided layer with a spiral layer or a loop layer. The spiral layer or the loop layer is formed by winding the fibers in a spiral or loop shape onto the outer surface of the liner. The braided layer is formed by winding the fibers in an interlaced manner with a larger fiber spacing compared to the spiral layer or the loop layer.

[0013] In a preferred embodiment, the resin is impregnated in a fiber layer consisting of a first braided layer, a spiral layer or a loop layer, and a second braided layer. The first braided layer is formed by winding the fibers in an interlaced manner around the outer surface of the dome. The spiral layer or the loop layer is formed by continuously winding the fibers from the first braided layer in a spiral or loop shape around the outer surface of the straight portion. The second braided layer is formed by continuously winding the fibers from the first braided layer in an interlaced manner, with the fiber spacing increasing compared to the spiral layer or the loop layer, around the outermost layer of the spiral layer or the loop layer.

[0014] Another aspect of the present invention is a method for manufacturing a can having a reinforcing layer formed by impregnating a fiber layer with resin. The fiber layer is formed by radially overlapping and winding fibers onto the outer surface of a hollow liner having a cylindrical straight body and a dome that gradually narrows from the axial end of the straight body toward the side opposite to the straight body. The manufacturing method is characterized by comprising the following steps: forming the fiber layer by overlapping a braided layer onto the outermost layer of a spiral or loop layer, wherein the spiral or loop layer is formed by winding the fibers in a spiral or loop shape onto the outer surface of the liner, and the braided layer is formed by winding the fibers in an interlaced braided manner with a larger fiber spacing compared to the spiral or loop layer; and impregnating the resin onto the fiber layer formed by overlapping the braided layer onto the outermost layer of the spiral or loop layer.

[0015] In a preferred embodiment, the process includes: a step of forming the fiber layer from a first braided layer, a spiral layer or a loop layer, and a second braided layer, wherein the first braided layer is formed by winding the fibers in an interlaced manner around the outer surface of the dome; the spiral layer or the loop layer is formed by continuously winding the fibers from the first braided layer in a spiral or loop shape around the outer surface of the straight portion; and the second braided layer is formed by continuously winding the fibers from the first braided layer in an interlaced manner with a larger fiber spacing compared to the spiral layer or the loop layer around the outermost layer of the spiral layer or the loop layer; and a step of impregnating the fiber layer, which is composed of the first braided layer, the spiral layer or the loop layer, and the second braided layer, with resin.

[0016] In a preferred embodiment, a tow prepreg, in which a thermoplastic resin is impregnated into the fibers, is used as part or all of the fibers constituting the braided layer.

[0017] In another preferred embodiment, the resin is composed of a thermosetting resin, wherein the melting temperature of the thermoplastic resin is below the curing temperature of the thermosetting resin.

[0018] In another preferred embodiment, the thermoplastic resin is composed of a thermoplastic resin compatible with the resin.

[0019] In another preferred embodiment, the thermoplastic resin is composed of the same thermoplastic resin as the resin.

[0020] Invention Effects

[0021] According to one aspect of the present invention, by changing the winding method of the fibers according to their position, it is possible to prevent fiber misalignment during resin injection and suppress strength reduction. Attached Figure Description

[0022] Figure 1 This is a schematic side view of the high-pressure tank (with a fiber-wrapped liner) according to this embodiment.

[0023] Figure 2 This is a cross-sectional view schematically showing the structure of the high-pressure tank (with a fiber-wound liner) according to this embodiment.

[0024] Figure 3 This is a schematic diagram showing a manufacturing apparatus (braiding machine) for winding fibers into the inner lining of the high-pressure tank according to this embodiment.

[0025] Figure 4 This is a schematic diagram showing the release position of the fiber when it is wound into the dome of the high-pressure tank according to this embodiment.

[0026] Figure 5 This is a schematic diagram showing the fiber release position when the fiber is wound into the straight part of the high-pressure tank according to this embodiment.

[0027] Figure 6 This is a longitudinal sectional view showing the state of the preform preparation process and the vacuum degassing process of the manufacturing apparatus (resin impregnation molding mold) for the high-pressure tank according to this embodiment.

[0028] Figure 7 This is a longitudinal sectional view showing the state of the resin injection process of the manufacturing apparatus (resin impregnation molding mold) for the high-pressure tank according to this embodiment.

[0029] Figure 8 This is a side view schematically illustrating another example of a high-pressure tank (with a fiber-wrapped liner) according to this embodiment. Detailed Implementation

[0030] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0031] The following description uses a high-pressure tank for a fuel cell vehicle as an example of a tank. However, the tanks to which this invention is applied are not limited to high-pressure tanks for fuel cell vehicles, and the shape, raw materials, etc., of the inner lining or preform constituting the tank are not limited to the examples shown in the figure.

[0032] In the RTM process, a preform with a fiber layer formed on the outer surface of the liner is created by multiple (multi-layer) winding (winding) of carbon fibers into the liner. Epoxy resin is then impregnated into the fiber layer of the preform and cured, thereby manufacturing a high-pressure tank for fuel cell vehicles with a fiber-reinforced resin layer containing carbon fibers and epoxy resin formed on the outer periphery of the liner. The liner is a hollow container made of resin (e.g., nylon resin) that forms the internal space of the high-pressure tank.

[0033] High-pressure tanks for fuel cell vehicles require large tanks where epoxy resin is filled and impregnated in thick-walled laminates (carbon fibers wound into thick walls) using high-speed, high-pressure methods. This results in fiber misalignment and other issues. In particular, the straight sections of the inner liner require reinforcement from carbon fibers (see Patent Document 2). Therefore, the carbon fibers need to be tightly (without gaps) wound. As a result, fiber misalignment during RTM resin impregnation can easily lead to performance degradation and poor quality.

[0034] Therefore, this embodiment adopts the following structure.

[0035] (Structure of the high-pressure tank)

[0036] First, the structure of the high-pressure tank 10 according to the embodiments of the present invention will be described in detail based on the accompanying drawings. Figure 1 , Figure 2 These are schematically shown side views and cross-sectional views of the high-pressure tank 10 (with a fiber-wrapped liner) according to this embodiment. Additionally, Figure 1 The right half of the diagram shows the state after the outermost (outer surface) woven layer has been removed. For ease of explanation, arrow D, appropriately indicated in each figure, will be designated as the axial direction of the high-pressure tank 10, and arrow R as the radial direction. The side of the high-pressure tank 10 furthest from the center of the high-pressure tank 10 (inner liner 12) along its central axis CL will be designated as the "axial end side." Conversely, the side closer to the center of the high-pressure tank 10 (inner liner 12) will be designated as the "axial central part side." Furthermore, the high-pressure tank 10 according to this embodiment is filled with, for example, hydrogen as fuel, and is used in fuel cell vehicles (figures omitted).

[0037] like Figure 1 , Figure 2 As shown, the high-pressure tank 10 has an inner liner 12 that serves as the main body of the container. As an example, the inner liner 12 is blow-molded from a liquid crystal resin material with excellent gas barrier properties and excellent dimensional stability, and has a cylindrical straight body portion 12A and a generally hemispherical dome 12B integrally formed at both ends (end openings) of the straight body portion 12A. More specifically, the inner liner 12 has: a cylindrical straight body portion 12A with a constant inner and outer diameter at the middle portion along the longitudinal direction (axial direction); and dome 12Bs that gradually narrow towards the side opposite to the straight body portion 12A (axial end side) (narrowing diameter) along the longitudinal direction (axial direction) of the inner liner 12.

[0038] Additionally, the dome 12B includes a cylindrical portion 12C at its axial center that protrudes towards the axial end (outer side) of the central axis CL of the inner liner 12. The inner and outer diameters of the cylindrical portion 12C are smaller and substantially constant than those of the straight portion 12A.

[0039] Furthermore, the high-pressure tank 10 is constructed by winding strip-shaped fibers (also called fiber bundles) 16 of a predetermined width in layers around the outer peripheral surface of the straight portion 12A and the outer peripheral surface of the dome 12B of the liner 12. The fibers 16 are made of fiber-reinforced plastics (FRP) containing glass fibers, carbon fibers, or aramid fibers, and a fiber-reinforced plastic layer (FRP layer) is formed as a reinforcing layer on the outer peripheral surface (outer surface) of the liner 12.

[0040] Specifically, fibers 16 are wound in an interlaced braided manner (hereinafter sometimes referred to as "braided winding") on the outer peripheral surface (outer surface) of the dome 12B, forming a braided layer 17B as the first fiber layer. Then, by applying thermosetting resin 18 ( Figure 7The reinforcing layer is formed by impregnating and curing the woven layer (first fiber layer) 17B.

[0041] On the other hand, fibers 16 are spirally wound (hereinafter sometimes referred to as "spiral winding") on the outer peripheral surface (outer surface) of the straight portion 12A, and the spirally wound fibers 16 form a spiral layer 17A as a second fiber layer. Then, by applying thermosetting resin 18 ( Figure 7 The reinforcing layer is formed by impregnating and curing the spiral layer (second fiber layer) 17A.

[0042] The term "spiral winding" refers to the process of winding the fiber 16 relative to the central axis CL of the liner 12 at a predetermined winding angle +θ onto the entire outer peripheral surface of the straight portion 12A, and then further winding it (crossing over the fiber 16 wound at angle +θ) relative to the central axis CL of the liner 12 at a predetermined winding angle -θ. In other words, the spiral layer (second fiber layer) 17A is formed by winding at least two layers of fiber 16 on the outer peripheral surface of the straight portion 12A at predetermined winding angles +θ and -θ. Furthermore, although due to factors such as the internal pressure of the straight portion 12A and the number of fibers in the fiber (bundle) 16, the fiber (bundle) 16 is actually wound in, for example, several to several dozen layers (overlapping or stacking radially).

[0043] As described above, the so-called weaving and winding refers to winding the fibers 16 in an interlaced manner, which here means winding them around the entire outer periphery of the dome 12B at a specified winding angle +θ and winding angle -θ relative to the central axis CL of the lining 12.

[0044] That is, both the braiding and the spiral winding are performed at the same winding angle θ, which is within the range of θ = 54.7 degrees ± 10 degrees, preferably within the range of θ = 54.7 degrees ± 5 degrees, and more preferably within the range of θ = 54.7 degrees ± 1 degree, including tolerance.

[0045] The winding angle θ is derived from the stress (axial stress and circumferential stress) in the straight section 12A under a specified internal pressure, and is an angle generated because the circumferential stress is twice that of the axial stress. That is, although detailed calculation formulas are omitted, when calculating the winding angle θ corresponding to the stress based on netting theory, since tan... 2 Since θ = 2, we can derive θ = 54.7 degrees (equilibrium angle).

[0046] Here, the dome 12B experiences less stress under internal pressure compared to the straight body 12A, therefore, the degree of reinforcement required is less than that of the straight body 12A. Thus, as a basic structure, the dome 12B is formed with a woven coil (woven layer 17B) that has a larger fiber spacing, sparser fiber density, and lower strength compared to the spiral coil (spiral layer 17A), while the straight body 12A is formed with a spiral coil (spiral layer 17A) that has a smaller fiber spacing, denser fiber density, and higher strength compared to the woven coil (woven layer 17B) (see reference). Figure 1 (the right half)

[0047] Furthermore, although detailed structural descriptions are omitted, when viewed from a direction orthogonal to the central axis CL of the lining 12, the switching from the woven winding (woven layer 17B) in the dome 12B to the spiral winding (spiral layer 17A) in the straight body 12A, and conversely, the switching from the spiral winding (spiral layer 17A) in the straight body 12A to the woven winding (woven layer 17B) in the dome 12B, occurs within a specified length region along the axial direction near the boundary between the straight body 12A and the dome 12B.

[0048] Additionally, although the illustration is omitted, as an example, a sealing plug is fitted into one cylindrical section 12C, and a connector plug is fitted into another cylindrical section 12C, on which a valve is installed.

[0049] In addition, such as Figure 3 As shown, fiber 16 is wound around the outer periphery of lining 12 by a known manufacturing device (also called a weaving machine) 40. Figure 4 , Figure 5 As shown, the manufacturing apparatus 40 has a plurality of spools 42, 44 arranged in two rows on the circumference, and fibers 16 released from each row of spools 42, 44 are sequentially wound around the central axis CL. Figure 3 The outer peripheral surface of one dome 12B, the outer peripheral surface of the straight body 12A, and the outer peripheral surface of the other dome 12B of the inner lining 12 (moving to the left).

[0050] Additionally, when weaving the wound fibers 16 into one dome 12B and the other dome 12B, as Figure 4 As shown, a plurality of spools 42 connected by solid lines and a plurality of spools 44 connected by imaginary lines are arranged circumferentially and alternately in the radially inner and radially outer directions. Furthermore, the manufacturing apparatus 40 is driven to move the plurality of spools 42 connected by solid lines and the plurality of spools 44 connected by imaginary lines in opposite directions, and the aforementioned spools 42, 44 are sequentially interchanged from radially inner to radially outer and from radially outer to radially inner.

[0051] Additionally, when spirally winding the fiber 16 into the straight portion 12A, as... Figure 5 As shown, a plurality of spools 42 connected by solid lines and a plurality of spools 44 connected by imaginary lines are arranged circumferentially and radially outward and radially inward. Furthermore, the manufacturing apparatus 40 is driven to move the plurality of spools 42 connected by solid lines and the plurality of spools 44 connected by imaginary lines in opposite directions.

[0052] As described above, in this embodiment, as the basic structure, the dome 12B is formed with a woven layer (woven layer 17B) having large fiber spacing, sparse fiber density, and low strength, while the straight body 12A is formed with a spiral layer (spiral layer 17A) having small fiber spacing, dense fiber density, and high strength (see reference). Figure 1 The right half of the part is included, but in order to prevent the fiber 16 (especially the fiber 16 of the spiral layer 17A in the straight part 12A) from shifting during resin injection, the following structure is added.

[0053] That is, such as Figure 1 , Figure 2 As shown, in the outermost layer of the spiral layer 17A (e.g., composed of several to dozens of layers), the fibers 16 are continuously wound in an interlaced manner from the braided layer 17B to form the braided layer 17E.

[0054] Specifically, on the outermost layer of the woven layer 17B on the outer periphery (outer surface) of the dome 12B, after the fibers 16 are wound in an interlaced manner (after weaving and winding), from this point onwards (in other words, without switching from weaving and winding to spiral winding), the fibers 16 are continuously (in other words, without switching from weaving and winding to spiral winding) wound in an interlaced manner onto the spiral layer 17A (the spiral layer 17A adjacent to the woven layer 17B) on the outer periphery (outer surface) of the straight body 12A. Figure 2 (Part 17E). After the fibers 16 are wound in an interlaced manner on the spiral layer 17A on the outer peripheral surface (outer surface) of the straight body 12A, the fibers 16 are continuously wound in an interlaced manner on the braided layer 17B (the braided layer 17B adjacent to the spiral layer 17A) on the outer peripheral surface (outer surface) of another dome 12B, thereby further forming a braided layer 17B on the outer peripheral surface (outer surface) of the other dome 12B.

[0055] In other words, in the outermost layer of the fiber layer (covering the entire axial length of the liner 12) of the woven layer 17B in the outer peripheral surface of one dome 12B containing the liner 12, the spiral layer 17A in the outer peripheral surface of the straight body 12A, and the woven layer 17B in the outer peripheral surface of the other dome 12B, woven layers (17B, 17E, 17B) are formed by winding fibers 16 in an interlaced weave. Furthermore, the woven layer 17E, formed by overlapping or stacking on the outermost layer of the spiral layer 17A, can be a single layer or multiple layers (e.g., several layers). Figure 2 The example shown is an example of a single woven layer 17E.

[0056] Therefore, by interlacing the outermost layer (continuously from the braided layer 17B) of the spiral layer 17A, which has small fiber spacing and dense fibers and is prone to fiber misalignment, a braided layer 17E with large fiber spacing and sparse fibers and is not prone to fiber misalignment is formed (in other words, the outermost layer of the spiral layer 17A, which is prone to fiber misalignment, is covered by the braided layer 17E, which is not prone to fiber misalignment). Thus, the misalignment of the fibers 16 during resin injection, as described later, can be prevented.

[0057] The high-pressure tank 10 is formed by impregnating a fluid, uncured thermosetting resin (e.g., a resin made by mixing epoxy resin and a curing agent; sometimes simply referred to as "resin" in this specification) 18 into a fiber layer 17 and then heating the thermosetting resin to cure it. The fiber layer 17 includes a braided layer 17B, a spiral layer 17A, and a braided layer 17E, formed as described above by winding fibers 16 in layers around an inner liner 12.

[0058] (Manufacturing method of high-pressure tank)

[0059] The manufacturing method of the high-pressure tank 10 with the above structure will be described in detail based on the accompanying drawings.

[0060] (Fiber winding process)

[0061] The high-pressure tank 10 according to this embodiment is constructed by first winding fibers 16 around the outer peripheral surface of the inner liner 12. That is, as shown in the figure... Figures 3-5 As shown, fibers 16 are sequentially released from multiple spools 42 and 44 of the manufacturing apparatus 40, and the fibers 16 are first woven and wound around the outer peripheral surface of a dome 12B to form a braided layer 17B (first step). In detail, the fibers 16 are sequentially woven and wound from the end of the dome 12B opposite to the side of the straight body 12A to the end of the straight body 12A side to form the braided layer 17B.

[0062] After the fiber 16 is wound around the outer periphery of a dome 12B, the fiber 16 is then spirally wound around the outer periphery of the straight body 12A to form a spiral layer 17A (second step). Specifically, the spiral layer 17A is formed by spirally winding the fiber 16 sequentially from one end of the straight body 12A on the side of a dome 12B to the other end of the straight body 12A. Furthermore, the switching from the weaving and winding in the dome 12B to the spiral winding in the straight body 12A is achieved by switching the arrangement of multiple spools 42, 44 of the manufacturing apparatus 40 for a predetermined time width. Figure 4 , Figure 5 The winding process takes place axially within a defined length of region near the boundary between the dome 12B and the straight section 12A. Within this region, the fiber 16 can smoothly switch from braided winding to helical winding at the same winding angle θ.

[0063] After the spiral winding of fiber 16 relative to the outer peripheral surface of the straight portion 12A is completed, the fiber 16 is then woven around the outer peripheral surface of another dome 12B to form a braided layer 17B (third step). Specifically, the braided layer 17B is formed by sequentially weaving the fiber 16 from the end of the dome 12B on the side of the straight portion 12A to the end on the side opposite to the straight portion 12A. Furthermore, the switching from the spiral winding in the straight portion 12A to the braided winding in the dome 12B is achieved by switching the arrangement of multiple spools 42, 44 of the manufacturing apparatus 40 for a predetermined time width. Figure 4 , Figure 5 The winding process takes place axially within a defined length region near the boundary between the straight section 12A and the dome 12B. Within this region, the fiber 16 can smoothly switch from helical winding to braided winding at the same winding angle θ.

[0064] In addition, the winding angle θ of the fiber 16 wound around one dome 12B and the other dome 12B and the straight body 12A is, for example, in the range of 54.7 degrees ± 10 degrees.

[0065] Furthermore, in this embodiment, in the outermost layer of the braided layer 17B, after the braiding and winding of the fiber 16 is completed, the switching from the braiding and winding in the dome 12B to the spiral winding in the straight body 12A as described above is not performed. Instead, the fiber 16 is braided and wound on the outer peripheral surface of the straight body 12A (specifically, the outer peripheral surface of the spiral layer 17A in the outer peripheral surface of the straight body 12A) to form the braided layer 17E. In addition, after the braiding and winding of the fiber 16 relative to the outer peripheral surface of the straight body 12A (specifically, the outer peripheral surface of the spiral layer 17A in the outer peripheral surface of the straight body 12A) is completed (without the switching from the spiral winding in the straight body 12A to the braiding and winding in the dome 12B as described above), the fiber 16 is then braided and wound on the outer peripheral surface of another dome 12B to form the braided layer 17B.

[0066] In other words, in the outermost layer such as the woven layer 17B, the fibers 16 are sequentially woven to form woven layers (17B, 17E, 17B) from the end of one dome 12B opposite to the side of the straight body 12A to the end of another dome 12B opposite to the side of the straight body 12A (over the entire axial length of the lining 12).

[0067] By winding the fibers 16 as described above, the outermost layer of the spiral layer 17A is continuously overlapped (layered) from the braided layer 17B to form the braided layer 17E.

[0068] As described above, by ultimately (overlapping or stacking in the radial direction) winding the fibers 16, for example, several to several tens of layers, a preform 11 is formed on the outer peripheral surface (outer surface) of the hollow liner 12 as an intermediate body of the fiber layer 17 (braided layer 17B, spiral layer 17A, braided layer 17E) formed by the winding fibers 16. Figure 6 , Figure 7 ).

[0069] (Resin injection (resin impregnation molding) process)

[0070] As described above, a preform 11 with a fiber layer 17 is formed by winding fibers 16 around a hollow inner liner 12. Figure 6 , Figure 7 Thermosetting resin 18 is placed in a resin impregnation molding mold 50 (between the lower mold 60 and the upper mold 80, also called a cavity) which is a manufacturing device. Thermosetting resin 18 is injected into the mold 50, so that the thermosetting resin 18 impregnates the fiber layer 17 (the fiber 16 constituting the fiber layer 17) and the thermosetting resin 18 is heated to cure it.

[0071] To explain in detail, such as Figure 6 , Figure 7As shown, a vacuum degassing pipe 62 connected to a vacuum pump 61 is embedded in the mold 50 (the lower mold 60 in the example).

[0072] Additionally, a resin injection pipe (also called a resin injection gate) 82 connected to a resin injection machine 81 is embedded in the mold 50 (upper mold 80 in the example).

[0073] When the thermosetting resin 18 is impregnated into the fiber layer 17 (fibers 16 constituting the fiber layer 17) of the preform 11, firstly, with the preform 11 placed in a mold 50 having the above structure (between the lower mold 60 and the upper mold 80) and kept at a specified temperature (a temperature above the curing temperature of the thermosetting resin 18) (in other words, after mold closing), the vacuum pump 61 is controlled to perform vacuum degassing inside the mold 50. Figure 6 ).

[0074] After the above vacuum degassing is stopped (completed), thermosetting resin 18 is injected into the mold 50 by driving the resin injection machine 81. Figure 7 ).

[0075] Therefore, the (uncured) resin 18 injected (discharged) into the mold 50 (cavity) through the resin injection pipe 82 is impregnated by the braided layer 17E onto the spiral layer 17A and the braided layer 17B (i.e., the entire fiber layer 17). At this time, since the outermost layer of the preform 11 (fiber layer 17) is provided with the braided layer 17E, which is less prone to fiber shifting (in other words, covered by the braided layer 17E, which is less prone to fiber shifting), the shifting of the fibers 16 (especially the fibers 16 of the spiral layer 17A in the straight body portion 12A) during the injection (impregnation) of the resin 18 is suppressed. In addition, compared with the spiral layer 17A (spiral winding), the braided layer 17E (braided winding) has a larger fiber spacing and a sparser fiber (density), so it does not hinder the injection (impregnation) of the resin 18 into the inner spiral layer 17A.

[0076] After the resin 18 is impregnated into the fiber layer 17, the resin injection is stopped and the resin 18 is heated to cure it, thereby forming a fiber-reinforced resin layer as a reinforcing layer on the outer periphery of the liner 12. As a result, a high-pressure tank 10 with excellent corrosion resistance, lightweight and low cost, and easy handling and disposal can be obtained.

[0077] As explained above, in the high-pressure tanks for fuel cell vehicles, when manufacturing the tanks using RTM impregnation technology, epoxy resin needs to be filled and impregnated in a large tank with thick-walled stacks (where carbon fibers are wound into thick walls) by applying high speed and high pressure. At this time, the carbon fibers wound around the preform are deviated, and the fiber width is reduced, resulting in reduced productivity and tank performance.

[0078] In this embodiment, to enhance the effect, a fiber stack (braided layer 17E) is created by weaving a densely wound fiber bundle, such as a preform with small gaps between the fiber bundles, into the outermost layer of the preform. This creates a fiber stack that is less prone to shifting and has large gaps between the fiber bundles.

[0079] Since the carbon fiber stack is not prone to shifting and the carbon fiber width does not shrink, performance degradation can be suppressed. Even if such fiber shift prevention measures are taken, the large gaps in the carbon fiber weaving (woven layer 17E) can be addressed without reducing resin impregnation.

[0080] Therefore, when injecting epoxy resin, it is possible to prevent carbon fiber misalignment and fiber width reduction, thus improving resin impregnation and tank performance and achieving good surface quality in the high-pressure tank 10.

[0081] Thus, according to this embodiment, by changing the winding method of the fiber 16 according to its position, it is possible to prevent the fiber 16 from shifting or the fiber width from shrinking during resin injection, thereby suppressing the reduction in strength.

[0082] Additionally, for example, to more reliably prevent fiber misalignment during resin injection, such as... Figure 8 As shown, some or all of the fibers 16 (constituting the braided layer 17E) that are woven and wound around the outermost layer of the fiber layer 17 may also be made of a tow prepreg 19 formed by impregnating fibers (e.g., carbon fibers) with a thermoplastic resin (e.g., epoxy resin). In other words, the outermost layer of the fiber layer 17 may also be formed by replacing some or all of the aforementioned fibers 16 with the tow prepreg 19 and then weaving and winding them.

[0083] In this case, when winding the outermost layer using the manufacturing apparatus 40, it is sufficient to replace some or all of the multiple spools 42, 44 with spools filled with filament prepreg 19 to wind the outermost layer.

[0084] When the preform 11, formed by weaving and winding the prepreg 19 of the outermost layer of fiber layer 17, is placed in a mold 50 that is kept at a predetermined temperature (a temperature above the curing temperature of the thermosetting resin 18), for example, if the melting temperature of the thermoplastic resin constituting the prepreg 19 is below the curing temperature of the thermosetting resin 18, the thermoplastic resin constituting the prepreg 19 melts, and the fibers constituting the prepreg 19 (i.e., the fibers constituting the braided layer 17E) bond to the fibers 16 constituting the spiral layer 17A on its inner side, and the fibers 16 constituting the spiral layer 17A bond to each other, thus more effectively preventing fiber displacement during resin injection. Furthermore, by bonding the thermoplastic resin constituting the innermost layer of prepreg 19 to the liner 12, fiber displacement can be prevented more effectively.

[0085] Furthermore, since the thermoplastic resin constituting the tow prepreg 19 together with the thermosetting resin 18 (the resin impregnated in the fiber layer 17) forms a reinforcing layer (fiber-reinforced resin layer), a thermoplastic resin that has good compatibility and high adhesion to the thermosetting resin 18 is preferred. For example, the thermoplastic resin constituting the tow prepreg 19 is preferably the same thermoplastic epoxy resin as the epoxy resin constituting the thermosetting resin 18. That is, it is preferable to use an epoxy resin that has both thermosetting and thermoplastic properties (melting temperature below the curing temperature).

[0086] That is, in this embodiment, when winding dozens of carbon fibers by multiple fiber winding (FW) such as braiding and winding, part or all of the carbon fiber spool is replaced with a tow prepreg (TPP) containing a thermoplastic epoxy resin that is compatible with and has high adhesion to the epoxy resin impregnated in the fiber layer, and the outermost layer is wound around it, thereby preventing fiber displacement during resin injection during RTM molding.

[0087] Therefore, based on Figure 1 , Figure 2 Similarly, in the embodiments described above, when injecting epoxy resin, it is possible to prevent carbon fiber misalignment and fiber width reduction, thus improving resin impregnation properties and tank performance, and achieving good surface quality in the high-pressure tank 10.

[0088] In addition, in the above embodiment, the braided layer 17E is formed by overlapping the entire surface of the outermost layer of the fiber layer 17 (spiral layer 17A) (in a manner that covers the entire outer peripheral surface of the spiral layer 17A), but of course, the braided layer 17E may only be formed by overlapping a portion of the surface of the outermost layer of the fiber layer 17 (spiral layer 17A).

[0089] Alternatively, fibers can be spirally wound (spiral winding) on ​​the outer peripheral surface of the straight portion 12A to form a spiral layer, but for example, the winding angle θ can be appropriately adjusted to form a ring-shaped layer by spirally winding (ring winding) on ​​the outer peripheral surface of the straight portion 12A.

[0090] Furthermore, the inner liner 12 is not limited to being made of liquid crystal resin. The inner liner 12 may also be made of other synthetic resins with gas barrier properties, such as high-density polyethylene, or lightweight metals such as aluminum alloy. Additionally, the inner liner 12 is not limited to being manufactured by blow molding; it may also be manufactured by injection molding or the like.

[0091] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the specific structure is not limited to these embodiments. Even if there are design changes that do not depart from the spirit of the present invention, they are also included in the present invention.

[0092] Label Explanation

[0093] 10. High-pressure tank (cabin)

[0094] 11 Preform

[0095] 12 Lining

[0096] 12A Straight Body

[0097] 12B Dome

[0098] 12C Cylindrical section

[0099] 16 Fibers

[0100] 17. Fiber layer

[0101] 17A Spiral Layer

[0102] 17B Braided Layer (First Braided Layer)

[0103] 17E Braided Layer (Second Braided Layer)

[0104] 18. Thermosetting resins (resins)

[0105] 19. Towed Prepreg

[0106] 50 molds

[0107] 60 Lower mold

[0108] 80 upper mold

[0109] CL central axis

Claims

1. A can having a reinforcing layer formed by impregnating a fiber layer with resin, the fiber layer being formed by radially overlapping and winding fibers on the outer surface of a hollow inner liner having a cylindrical straight body portion and a dome that gradually narrows from an axial end of the straight body portion toward a side opposite to the straight body portion, the can being characterized in that... The fiber layer is configured such that the resin is impregnated on the outermost layer of a braided layer overlapping a spiral layer or a loop layer. The spiral layer or the loop layer is formed by winding the fibers in a spiral or loop shape around the outer surface of the lining. The braided layer is formed by winding the fibers in an interlaced manner with larger fiber spacing compared to the spiral layer or the loop layer. The braided layer and the spiral layer or the loop layer are all wound at the same winding angle, which, including tolerance, is within the range of 54.7 degrees ± 10 degrees. The can is configured such that the resin is impregnated in a fiber layer consisting of a first braided layer, a spiral layer or a loop layer, and a second braided layer. The first braided layer is formed by winding the fibers in an interlaced manner around the outer surface of the dome. The spiral layer or the loop layer is formed by continuously winding the fibers from the first braided layer in a spiral or loop shape around the outer surface of the straight portion. The second braided layer is formed by continuously winding the fibers from the first braided layer in an interlaced manner, with the fiber spacing increasing compared to the spiral layer or the loop layer, around the outermost layer of the spiral layer or the loop layer. The first woven layer is formed only on the outer surface of the dome, the spiral layer or loop layer is formed on the outer surface of the straight body, and the second woven layer is formed.

2. A method for manufacturing a can, the can having a reinforcing layer formed by impregnating a fiber layer with resin, the fiber layer being formed by radially overlapping and winding fibers onto the outer surface of a hollow inner liner having a cylindrical straight body portion and a dome that gradually narrows from the axial end of the straight body portion toward a side opposite to the straight body portion, the manufacturing method being characterized by comprising the following steps: The process of forming the fiber layer by overlapping a braided layer onto the outermost layer of a spiral layer or a loop layer, wherein the spiral layer or the loop layer is formed by winding the fibers in a spiral or loop shape around the outer surface of the lining, and the braided layer is formed by winding the fibers in an interlaced manner with larger fiber spacing compared to the spiral layer or the loop layer, wherein... The braided layer and the spiral layer or the loop layer are all wound at the same winding angle, which is within the range of 54.7 degrees ± 10 degrees, including tolerance; and The process of impregnating the resin into the fiber layer formed by overlapping the braided layer with the outermost layer of the spiral layer or the loop layer. The method for manufacturing the can includes the following steps: The process of forming the fiber layer from a first braided layer, a spiral layer or a loop layer, and a second braided layer, wherein the first braided layer is formed by winding the fibers in an interlaced manner around the outer surface of the dome; the spiral layer or the loop layer is formed by continuously winding the fibers from the first braided layer in a spiral or loop shape around the outer surface of the straight portion; and the second braided layer is formed by continuously winding the fibers from the first braided layer in an interlaced manner with larger fiber spacing compared to the spiral layer or the loop layer around the outermost layer of the spiral layer or the loop layer, wherein only the first braided layer is formed on the outer surface of the dome, the spiral layer or the loop layer is formed on the outer surface of the straight portion, and the second braided layer is formed thereon; and The process of impregnating the resin into the fiber layer composed of the first braided layer, the spiral layer or the loop layer and the second braided layer.

3. The method for manufacturing a can according to claim 2, characterized in that, As part or all of the fibers constituting the braided layer, a tow prepreg made by impregnating the fibers with thermoplastic resin is used.

4. The method for manufacturing a can according to claim 3, characterized in that, The resin is composed of a thermosetting resin. The melting temperature of the thermoplastic resin is below the curing temperature of the thermosetting resin.

5. The method for manufacturing a can according to claim 3, characterized in that, The thermoplastic resin is composed of a thermoplastic resin that is compatible with the resin.

6. The method for manufacturing a can according to claim 3, characterized in that, The thermoplastic resin is composed of the same type of thermoplastic resin as the resin.

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