Manufacturing method of high pressure tank

Abstract

To provide a method for manufacturing high-pressure tanks that can more reliably increase the fracture strength of the reinforcement layer compared to conventional methods.SOLUTION: The manufacturing method of the invention is a method for manufacturing a high-pressure tank equipped with a reinforcing layer 4 on the outer surface of a liner 2 having a dome portion 6 at both ends 5e of a cylindrical body portion 5, comprising: a winding process for winding a band B (fiber bundle) of a predetermined tension containing a curable resin around the outer surface of the liner 2; and a reinforcing layer forming process for curing the curable resin contained in the band B (fiber bundle) to form the reinforcing layer, the winding process being characterized in that the tension of the band B (fiber bundle) at both ends 5e of the body 5 is reduced from the tension of the band B (fiber bundle) at the general portion 5g of the body 5 defined between the two ends 5e.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a high-pressure tank. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there has been known a high-pressure tank having a reinforcing layer on the outer peripheral surface of a cylindrical body portion of a liner (see, for example, Patent Document 1). The manufacturing method for this high-pressure tank includes the steps of forming a first reinforcing layer on the outer peripheral surface of the body of the liner by hoop winding tow prepreg (fiber bundle containing a curable resin), forming a second reinforcing layer on this first reinforcing layer by helically winding the tow prepreg, and curing the curable resin contained in the tow prepreg. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-73617 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional manufacturing method of a high-pressure tank (see, for example, Patent Document 1), when the fiber bundle is wound over the entire body of the liner along the axial direction of the body, the fiber bundle may collapse at both ends of the body. If the fiber bundle collapses, the breaking strength of the reinforcing layer may decrease.

[0005] An object of the present invention is to provide a method for manufacturing a high-pressure tank that can increase the breaking strength of a reinforcing layer more reliably than in the past. [Means for solving the problem]

[0006] The method for manufacturing a high-pressure tank of the present invention that achieves the above object is a method for manufacturing a high-pressure tank having a reinforcing layer on the outer surface of a liner having dome portions at both ends of a cylindrical body portion, the method comprising: a winding step of winding a fiber bundle containing a curable resin with a predetermined tension around the outer surface of the liner; and a reinforcing layer forming step of curing the curable resin contained in the fiber bundle wound around the outer surface to form the reinforcing layer, the winding step being performed such that the tension of the fiber bundle at both ends of the body portion is reduced below the tension of the fiber bundle in a general portion of the body portion defined between the both ends. The reinforcing layer is composed of a plurality of unit layers laminated on the outer surface of the liner, and the unit layers are formed by arranging the belt-shaped fiber bundles in parallel in the axial direction of the liner. It is characterized by: Effect of the Invention

[0007] According to the method for manufacturing a high-pressure tank of the present invention, the breaking strength of the reinforcing layer can be increased more reliably than in the past. [Brief description of the drawings]

[0008] [Figure 1] 1 is a vertical cross-sectional view of a high-pressure tank obtained by a manufacturing method according to an embodiment of the present invention. [Diagram 2] 2 is a partially enlarged cross-sectional view of a high-pressure tank obtained by a manufacturing method according to an embodiment of the present invention. FIG. [Diagram 3] 1 is a configuration explanatory diagram of a high-pressure tank manufacturing apparatus used in a manufacturing method according to an embodiment of the present invention. FIG. [Figure 4] FIG. 2 is an explanatory diagram of hoop winding of a fiber bundle performed in a manufacturing method according to an embodiment of the present invention. [Diagram 5] FIG. 4 is an explanatory diagram of a fiber bundle winding step performed in the manufacturing method according to the embodiment of the present invention. [Figure 6] FIG. 2 is an explanatory diagram of highly helical winding of a fiber bundle performed in a manufacturing method according to an embodiment of the present invention. [Figure 7] FIG. 2 is an explanatory diagram of low helical winding of a fiber bundle performed in a manufacturing method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Next, a mode (embodiment) for carrying out the present invention will be described in detail with reference to the drawings as appropriate. First, the structure of a high-pressure tank obtained by a manufacturing method according to this embodiment will be described. Fig. 1 is a vertical cross-sectional view of the high-pressure tank 1. Fig. 2 is a partially enlarged horizontal cross-sectional view of the high-pressure tank 1. The high-pressure tank 1 of this embodiment is assumed to be mounted on, for example, a fuel cell vehicle and store hydrogen gas to be supplied to a fuel cell system. However, the high-pressure tank 1 is not limited to this and may be used for other high-pressure gases.

[0010] As shown in FIG. 1, a high-pressure tank 1 includes a liner 2, a nozzle 3 connected to the liner 2, and a reinforcing layer 4 covering the outside of the liner 2 to the nozzle 3. The base 3 is assumed to be made of a metal material such as an aluminum alloy, etc. The base 3 has a cylindrical base body 3a having a supply and exhaust hole on the inside, and a flange portion 3b formed on one axial end side of the base body 3a.

[0011] The liner 2 is a hollow body made of a thermoplastic resin. Examples of the thermoplastic resin include, but are not limited to, polyamide resin and polyethylene resin. The liner 2 of this embodiment includes a cylindrical body portion 5 and dome portions 6 that are molded integrally with both ends of the body portion 5. As shown in FIG. 1, the dome portion 6 is a flattened bowl-shaped body that gradually decreases in diameter as it moves away from the body portion 5 side toward the outside in the direction of the axis Ax. The radial center of the dome portion 6 is recessed to correspond to the shape of the flange portion 3 b of the base 3 .

[0012] As shown in FIG. 1, the reinforcing layer 4 is formed from the outer surface of the liner 2 to the outer surface of the mouthpiece 3 . As will be described in detail later, this reinforcing layer 4 is formed by curing a curable resin contained in the tow prepreg wound from the liner 2 to the mouthpiece 3. The tow prepreg in this embodiment is composed of fiber bundles (tows) of reinforcing fibers containing a curable resin, and has adhesiveness. The curable resin of the tow prepreg is assumed to be, for example, a thermosetting resin such as an epoxy resin, a phenolic resin, an unsaturated polyester resin, or a polyimide resin, but is not limited to these. Examples of reinforcing fibers include, but are not limited to, carbon fibers, glass fibers, aramid fibers, boron fibers, alumina fibers, and silicon carbide fibers.

[0013] 2, the reinforcing layer 4 is made up of a plurality of unit layers 7 laminated on the outer surface of the liner 2. In this embodiment, the reinforcing layer 4 is assumed to be made up of nine unit layers 7 in the body portion 5 of the liner 2, but the number of unit layers 7 is not limited to this. The unit layer 7 is formed by arranging bands B (see Figure 3), which are strip-shaped fiber bundles fed from a band-feeding head 13b in a manufacturing apparatus 10 (see Figure 3) described below, in the axial direction of the liner 2 (perpendicular to the paper surface of Figure 2). These unit layers 7 are integrated together in a reinforcing layer forming step described later in which the curable resin of the tow prepreg is cured.

[0014] Next, a manufacturing device for the high-pressure tank 1 will be described. FIG. 3 is a diagram illustrating the configuration of the manufacturing apparatus 10. As shown in FIG. As shown in FIG. 3, the manufacturing apparatus 10 is mainly configured to include a feed mechanism 11 for the tow prepreg P, a guide mechanism 12 that guides the tow prepreg P ​​fed from the feed mechanism 11 to a winding mechanism 13, and a winding mechanism 13 that winds the tow prepreg P ​​guided by the guide mechanism 12 around the liner 2.

[0015] The let-off mechanism 11 includes a plurality of bobbins 11a around which the tow prepreg P ​​is traverse-wound, and a bobbin motor (not shown) that assists the rotation of the bobbins 11a so that the tow prepreg P ​​is pulled out from each of the bobbins 11a with a predetermined tension. In this embodiment, the let-off mechanism 11 is assumed to have five bobbins 11a. However, the number of bobbins 11a is not limited to this and can be changed as necessary.

[0016] The guide mechanism 12 includes a number of guide rollers 12a around which the tow prepregs P are stretched. The guide rollers 12a have a number of circumferential guide grooves (not shown) for individually guiding each of the tow prepregs P sent out from the feed mechanism 11. These circumferential guide grooves have flat bottom surfaces of a predetermined width. The tow prepregs P travel from the upstream feed mechanism 11 to the downstream winding mechanism 13 while contacting the bottom surfaces of these circumferential guide grooves. As a result, the cross-sectional shape of the tow prepregs P gradually becomes flattened.

[0017] In this embodiment, each guide roller 12a is assumed to collectively guide a plurality (five pieces) of tow prepregs P fed from the feed mechanism 11. However, the guide rollers 12a may also be configured as divided rollers that individually guide each of the tow prepregs P. Also, although the guide mechanism 12 in this embodiment has seven guide rollers 12a, the number of guide rollers 12a is not limited to this.

[0018] The winding mechanism 13 includes a drive unit 13a (rotary motor) that rotates the liner 2 about an axis Ax, and a band feeding head 13b that feeds the band B onto the rotating liner 2. The band-feeding head 13b arranges and integrates in the width direction a plurality (five) of tow prepregs P flattened by the guide mechanism 12. In this way, the band-feeding head 13b forms a band B, which is a belt-shaped tow prepreg P. The band feed head 13b is composed of a pair of pressure rollers 13b1, 13b1 arranged in parallel with a predetermined clearance. A plurality of (five) tow prepregs P arranged side by side on the upstream side of the band feed head 13b are press-molded into an expanded band B when passing between the pair of pressure rollers 13b1, 13b1.

[0019] Moreover, the band feeding head 13b is movable in the direction of the axis Ax of the liner 2 while feeding the band B to the rotating liner 2. Specifically, the band feeding head 13b moves in the direction of the axis Ax in response to the rotation of the liner 2 so that the unit layer 7 (see FIG. 2) is formed on the outer periphery of the liner 2. In this embodiment, a linear actuator 13c such as an air cylinder or a linear motor is assumed as a moving means for the band feeding head 13b, but is not limited thereto.

[0020] The band feed head 13b is configured to adjust the tension of the band B supplied to the liner 2. Specifically, the band feed head 13b adjusts the load applied to the tow prepreg P ​​in a direction intersecting the running direction of the tow prepreg P. In this embodiment, the tension adjustment means for the band B is assumed to be a gap adjustment actuator 13d provided between the linear actuator 13c and the band feed head 13b. Examples of the gap adjustment actuator 13d include, but are not limited to, a rack and pinion mechanism driven by a rotary motor and an air cylinder.

[0021] In addition, the gap adjustment actuator 13d in this embodiment is assumed to displace the band feed head 13b so that the detected tension becomes a preset target tension based on the detected tension of the tow prepreg P ​​or the band B. Note that a means for detecting the tension of the tow prepreg P ​​or the band B may be, but is not limited to, a sensor that detects the reaction force that the band feed head 13b receives from the tow prepreg P ​​or the band B.

[0022] Such a displacement control means of the band feed head 13b can be configured to include a program that instructs the spacing adjustment actuator 13d to set the detected tension of the tow prepreg P ​​or band B to a target tension, a ROM (Read Only Memory) that stores such a program, a RAM (Random Access Memory) that reads out and expands the program stored in the ROM, and a CPU (Central Processing Unit) that executes the expanded program and outputs commands to the spacing adjustment actuator 13d.

[0023] Next, a method for manufacturing the high-pressure tank 1 of this embodiment will be described. The manufacturing method of this embodiment includes a winding process in which a band B (see FIG. 3) made of a strip-shaped tow prepreg P ​​(see FIG. 3) is wound around the outer surface of a liner 2 (see FIG. 3), and a reinforcing layer forming process in which the curable resin contained in the tow prepreg P ​​wrapped around the outer surface of the liner 2 is cured to form a reinforcing layer 4 (see FIG. 2). Here, the manufacturing method of this embodiment will be specifically described by taking as an example a method of winding band B (see FIG. 3) around body portion 5 (see FIG. 3) of liner 2 (see FIG. 3) by hoop winding.

[0024] FIG. 4 is an explanatory diagram of the hoop winding of the band B around the liner 2. As shown in Fig. 4, hoop winding involves winding the band B in a hoop shape (ring shape) around the body portion 5 of the liner 2. That is, in hoop winding, the angle θ1 between the axis Ax and the extension direction D of the band B is set to an angle close to 90 degrees so that the band B is parallel to the axis Ax. As a result, the band B forms a unit layer 7 (see Fig. 2) on the outer peripheral surface of the body portion 5 of the liner 2, the unit layer 7 having approximately the same thickness as the thickness of the band B.

[0025] Fig. 5 is an explanatory diagram of the winding process of band B by hoop winding. Fig. 5 corresponds to a partially enlarged cross-sectional view of part V in Fig. 1. In Fig. 5, tensions Te1, Te2, Tg1, and Tg2 of band B are indicated by hollow arrows pointing downward on the paper for convenience of drawing. In this winding process, as shown in FIG. 5, a plurality of unit layers 7 are formed on the outer peripheral surface of the body portion 5 of the liner 2. The formation of the unit layers 7 in the hoop winding is performed by moving the band delivery head 13b back and forth over a distance corresponding to the length of the body portion 5 of the liner 2 relative to the rotating liner 2, as shown in FIG. 3. Specifically, the odd-numbered unit layers 7 (see FIG. 5) are formed on the forward path of the band delivery head 13b (see FIG. 3), and the even-numbered unit layers 7 (see FIG. 5) are formed on the return path. As a result, the first unit layer 7a, the second unit layer 7b, and the third unit layer 7c are formed on the outer peripheral surface of the body portion 5 in order from the liner 2 side, as shown in FIG. 5. Although not shown, further unit layers are stacked on the upper surface of the third unit layer 7c.

[0026] Furthermore, in such a winding process, the tension of the band B (fiber bundle) at both ends 5e of the body portion 5 of the liner 2 (in Figure 5, for convenience of drawing, only the end portion 5e on the left side of the paper is shown, and the end portion on the right side of the paper is omitted) is reduced below the tension of the fiber bundle in the general portion 5g of the body portion 5. In this embodiment, the end portion 5e of the body portion 5 refers to the portion adjacent to the dome portion 6. Moreover, the general portion 5g of the body portion 5 refers to the portion that occupies almost most of the body portion 5 and is defined between both end portions 5e of the body portion 5.

[0027] In addition, in each of the multiple unit layers 7a, 7b, 7c, etc. that are stacked on the outer peripheral surface of the body 5 of the liner 2, the tension of the band B (fiber bundle) at both end portions 5e is independently reduced compared to the tension of the band B (fiber bundle) in the general portion 5g. That is, in the first unit layer 7a shown in Fig. 5, the tension Te1 of the band B (fiber bundle) wound around the end portion 5e is lower than the tension Tg1 of the band B (fiber bundle) wound around the general portion 5g. Also, in the second unit layer 7b shown in Fig. 5, independently of the first unit layer 7a, the tension Te2 of the band B (fiber bundle) wound around the end portion 5e is lower than the tension Tg2 of the band B (fiber bundle) wound around the general portion 5g.

[0028] Note that, as shown in Fig. 5, for the band B (fiber bundle) wound around the end portion 5e of the body portion 5, it is sufficient that at least a part of the band B is wound around the end portion 5e. That is, the band B (fiber bundle) can be configured to wind around the joint portion 2a between the body portion 5 and the dome portion 6. Although not shown, the loop-wound band B (fiber bundle) can also be configured to wind around the end portion 5e so as not to extend toward the dome portion 6 side.

[0029] Also, as shown in Fig. 5, it is desirable that the tension of the band B (fiber bundle) of the plurality of unit layers 7a, 7b, 7c... laminated in the radial direction in the general portion 5g of the body portion 5 is reduced toward the outer peripheral side. That is, in the aspect shown in Fig. 5, it is desirable that the tension Tg2 of the second unit layer 7b is reduced compared to the tension Tg1 of the first unit layer 7a (Tg1>Tg2). Also, it is desirable that the tension Te1 at the end portion 5e of the first unit layer 7a is reduced compared to the tension Tg2 at the general portion 5g of the second unit layer 7b (Te1<Tg2). However, since the tension of the band B (fiber bundle) at both end portions 5e of each of the plurality of unit layers 7a, 7b, 7c... is reduced compared to the tension of the band B (fiber bundle) at the general portion 5g independently of each other, an aspect satisfying Tg1>Tg2 and Te1>Tg2 may also be acceptable. Also, it is desirable that the tension of the band B (fiber bundle) of the plurality of unit layers 7a, 7b, 7c... laminated in the radial direction at the end portion 5e of the body portion 5 is reduced toward the outer peripheral side. That is, in the aspect shown in Fig. 5, it is desirable that the tension Te2 of the second unit layer 7b is reduced compared to the tension Te1 of the first unit layer 7a (Te1>Te2).

[0030] The manufacturing method of this embodiment is assumed to involve winding band B (see FIG. 3) around the body portion 5 of the liner 2 by hoop winding, and then further winding band B (see FIG. 3) around the liner 2 (see FIG. 3) by helical winding, as shown in FIG. 4. Specifically, this manufacturing method is assumed to involve winding band B by high helical winding around band B (see FIG. 4) that has been wound around the body portion 5 by hoop winding, and further winding band B by low helical winding around band B that has been wound by high helical winding.

[0031] Fig. 6 is an explanatory diagram of the high helical winding of band B (see Fig. 3), and Fig. 7 is an explanatory diagram of the low helical winding of band B (see Fig. 3). As shown in Fig. 6, the high helical winding is set so that the angle θ2 between the band B (see Fig. 3) and the axis Ax direction and the extension direction D of the band B is approximately 75 degrees. As a result, the band B is wound around the body portion 5 of the liner 2 that has been hoop wound and the peripheral portion of the dome portion 6 adjacent to the body portion 5. As shown in Fig. 7, the low helical winding is set so that the angle θ3 of the band B (see Fig. 3) and the extending direction D of the band B with respect to the axial direction Ax is approximately 10 degrees. As a result, the band B is wound over the entire area from the body portion 5 to the dome portion 6 of the liner 2, which has been subjected to the hoop winding and high helical winding.

[0032] In the manufacturing method of this embodiment, the tension of the high helical wound band B (see FIG. 3) and the tension of the low helical wound band B (see FIG. 3) are set to be approximately the same as the tension of the outermost hoop wound band B (see FIG. 3) with respect to the general portion 5g (see FIG. 5). However, the tension of the high helical wound band B (see FIG. 3) and the tension of the low helical wound band B (see FIG. 3) can also be set to decrease toward the outer periphery of the reinforcing layer 4 (see FIG. 1).

[0033] In the reinforcing layer forming process, the liner 2 (see FIG. 3) that has completed the winding process is removed from the winding mechanism 13 (see FIG. 3) and heated to a predetermined temperature in a heating furnace (not shown). This hardens the hardening resin contained in band B (see FIG. 3) wrapped around liner 2. In the process of hardening the hardening resin, the stacked unit layers 7 (see FIG. 5) become integrated and adhere to the outer surface of liner 2. This forms reinforcing layer 4 (see FIG. 1), completing the series of manufacturing processes for high-pressure tank 1.

[0034] <Action and effect> Next, the effects of the method for manufacturing the high-pressure tank 1 according to this embodiment will be described. In the manufacturing method of this embodiment, the winding process of the band B (fiber bundle) around the liner 2 is performed so that the tension of the band B (fiber bundle) at both end portions 5e (see Figure 5) of the body portion 5 is reduced below the tension of the band B (fiber bundle) in the general portion 5g (see Figure 5) of the body portion 5. According to this manufacturing method, when the band B (fiber bundle) is wound over the entire torso 5 along the axial direction Ax of the torso 5 of the liner 2, it is possible to more reliably prevent the band B (fiber bundle) from becoming unwound at both ends 5e of the torso 5. As a result, the manufacturing method of this embodiment can more reliably increase the breaking strength of the reinforcing layer 4 compared to the conventional method (see, for example, Patent Document 1).

[0035] The winding step in this manufacturing method is performed by hoop-winding the band B (fiber bundle) around the body portion 5 of the liner 2. According to such a manufacturing method, the tension of the band B (fiber bundle) at both end portions 5e (see FIG. 5) can be more reliably reduced.

[0036] In this manufacturing method, the unit layer 7 (see FIG. 2) constituting the reinforcing layer 4 (see FIG. 2) is formed by arranging strip-shaped bands B (fiber bundles) in parallel in the axial direction Ax of the liner 2. According to such a manufacturing method, it is possible to more reliably control the tension of the band B (fiber bundle) in each unit layer 7. This makes it possible to equalize the difference between the tension of the band B (fiber bundle) in the general portion 5g and the tension of the band B (fiber bundle) in the end portion 5e.

[0037] In addition, in this manufacturing method, the tension of the band B (fiber bundle) at both end portions 5e (see FIG. 5) of the body portion 5 in each of the multiple unit layers 7 (see FIG. 5) is independently reduced from the tension of the band B (fiber bundle) in the general portion 5g (see FIG. 5) of the body portion 5. According to such a manufacturing method, it is possible to more reliably prevent the band B (fiber bundle) from collapsing at both end portions 5e (see FIG. 5) for each unit layer 7 (see FIG. 5). Moreover, it is preferable that the tension of the bands B (fiber bundles) of the plurality of unit layers 7 stacked in the radial direction at the end portion 5e of the body portion 5 decreases toward the outer periphery. According to such a manufacturing method, it is possible to more reliably prevent the band B (fiber bundle) from becoming unwound at both end portions 5e (see FIG. 5).

[0038] In addition, in this manufacturing method, it is desirable that the tension of the bands B (fiber bundles) of the multiple unit layers 7 (see FIG. 5) stacked in the radial direction of the general portion 5g is reduced toward the unit layer 7 on the outer periphery. This manufacturing method prevents the bandage effect, in which the inner layer band B (fiber bundle) is loosened due to the tension of the outer layer band B (fiber bundle) wrapped around the liner 2. This manufacturing method can more reliably increase the breaking strength of the reinforcing layer 4. Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be embodied in various forms. [Explanation of symbols]

[0039] 1. High pressure tank 2 Liner 4 Reinforcement layer 5. Torso 5e End of the body 5g General part of the torso 6 Dome section 7 Unit Layer

Claims

1. A method for manufacturing a high-pressure tank having a reinforcing layer on an outer surface of a liner having dome portions at both ends of a cylindrical body, comprising: a winding step of winding a fiber bundle containing a curable resin with a predetermined tension around the outer surface of the liner; a reinforcing layer forming step of forming the reinforcing layer by curing the curable resin contained in the fiber bundle wrapped around the outer surface; having the winding step is performed such that the tension of the fiber bundle at both end portions of the trunk portion is reduced below the tension of the fiber bundle in a general portion of the trunk portion defined between the both end portions, A method for manufacturing a high-pressure tank, characterized in that the reinforcing layer consists of a plurality of unit layers laminated on the outer surface of the liner, and the unit layers are formed by arranging the band-shaped fiber bundles in parallel in the axial direction of the liner.

2. 2. The method for manufacturing a high-pressure tank according to claim 1, wherein the winding step is performed by hoop-winding the fiber bundle around the body portion of the liner.

3. A method for manufacturing a high-pressure tank as described in claim 1, characterized in that the fiber bundle is wound around the joint between the body portion and the dome portion.

4. The method for manufacturing a high-pressure tank as described in claim 1, characterized in that the tension of the fiber bundles at both ends of the body portion of each of the multiple unit layers is independently reduced relative to the tension of the fiber bundles in the general portion of the body portion.

5. The method for manufacturing a high-pressure tank according to claim 4, characterized in that the tension of the fiber bundles of the plurality of unit layers radially stacked in the general portion of the barrel is reduced toward the unit layers on the outer periphery.

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