Method for manufacturing a tank

Abstract

To provide a method for producing a tank including a step of injecting a resin into a mold, with a preform being easily impregnated with the injected resin.SOLUTION: The method for producing a tank includes a step of preparing a preform having a liner and a fiber layer disposed on the outside of the liner, a step of disposing the preform inside an opened mold for use in impregnation of the fiber layer with a resin and disposing a fiber sheet woven into a network between the inner peripheral surface of the mold and the preform, and a step of injecting the resin between the inside of the mold and the preform after closing of the mold.SELECTED DRAWING: Figure 8

Description

Technical Field

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

Background Art

[0002] Citation Document 1 discloses a method for manufacturing a tank. In this method for manufacturing a tank, a preform with fibers laminated thereon is placed in a mold, and resin is injected into the mold while rotating the preform.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the method for manufacturing a tank described in Patent Document 1, there is a problem that since the resin hardly flows between the mold and the preform, it is difficult for the resin to spread over the entire preform.

Means for Solving the Problems

[0005] The present disclosure can be realized in the following forms.

[0006] According to one aspect of the present disclosure, there is provided a method for manufacturing a tank. The method includes the steps of: preparing a preform having a liner and a fiber layer disposed on the outer side of the liner; opening a mold for impregnating the fiber layer of the preform with resin, placing the preform inside the mold, and disposing a mesh-woven fiber sheet between the inner circumferential surface of the mold and the preform; and closing the mold and injecting resin between the interior of the mold and the preform. According to this tank manufacturing method, the mesh-woven fiber sheet is disposed between the interior of the mold and the preform, allowing the resin to spread through the fiber sheet. As a result, the resin can be impregnated to cover the entire preform. Furthermore, the fiber sheet presses the fiber layer, preventing the fiber layer from being sucked up into recesses during resin injection. Furthermore, the resin impregnating the fiber sheet forms a fiber-reinforced resin, thereby improving the strength of the tank. The present disclosure may be realized in various forms other than the tank manufacturing method, for example, a tank manufacturing apparatus, a tank manufactured by the tank manufacturing method, etc. [Brief explanation of the drawings]

[0007]

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Mode for Carrying Out the Invention

[0008] Figure 1 is an explanatory diagram showing a cross-section of a mold 100 parallel to the axis O of the tank. The preform 201 includes a liner 203 and a fiber layer 204. The preform 201 includes a liner 203 and a fiber layer 204. The liner 203 is a container for storing the gas to be stored in the tank 200 and is formed of, for example, polyethylene, which is a thermoplastic resin. Instead of polyethylene, the liner 203 may be formed of a thermoplastic resin such as polypropylene, polyvinyl chloride, polystyrene, polyamide resin, ethylene vinyl alcohol copolymer (EVOH), acrylonitrile butadiene styrene (ABS) resin, or the like. The fiber layer 204 is wound around the outer periphery of the liner 203. In the present embodiment, the fiber layer 204 is formed, for example, by a braider winding of carbon fibers. Braider winding is a winding method in which a large number of fibers are alternately crossed and wound around like knitting. An operator may form a fiber layer 204 in which a large number of fibers are alternately crossed around the outer periphery of the liner 203 by braider winding. Further, the operator may form the fiber layer 204 by hoop winding or helical winding of filamentous carbon fibers around the outer periphery of the liner 203. Carbon fibers or glass fibers can be used as the fibers of the fiber layer 204.

[0009] The mold 100 is a mold for impregnating the fiber layer 204 of the preform 201 with the resin Z to form the tank 200. In this embodiment, an epoxy resin, which is a thermosetting resin, is used as the resin Z. As the resin Z, a thermosetting resin such as a phenolic resin, a melamine resin, a urea resin, or a thermosetting polyimide resin may be used instead of the epoxy resin.

[0010] The mold 100 includes an upper mold 10 and a lower mold 20. The upper mold 10 has a runner 12. The lower mold 20 includes an exhaust passage 22 and a pressure holding portion 28. The pressure holding portion 28 has a cylinder 26 and a push pin 27. When the push pin 27 is pushed down, a space 29 is formed between the cylinder 26 and the push pin 27. The resin Z passes through the runner 12 and is injected into the gap 40 between the upper mold 10, the lower mold 20, and the preform 201. When the resin Z is injected with the push pin 27 pushed down, the pressure holding portion 28 stores the resin Z in the space 29. When the push pin 27 is pushed up, the resin Z stored in the space 29 is extruded into the gap between the upper mold 10, the lower mold 20, and the preform 201. At this time, the resin Z is impregnated into the fiber layer 204 of the preform 201.

[0011] Base caps 210 are attached to both longitudinal ends of the preform 201. A support portion 250 is connected to the base cap 210. The preform 201 is supported and arranged with a slight gap 40 between the inner peripheral surface 11 of the upper mold 10 and the inner peripheral surface 21 of the lower mold 20 by the support portion 250. The resin Z is injected into this gap 40.

[0012] FIG. 2 is an explanatory diagram showing a cross-section II-II that passes through the pressure holding portion 28 of FIG. 1. The pressure holding portion 28 is provided in the lower mold 20, but not in the upper mold 10. A slight gap 30 is provided between the closed upper mold 10 and the lower mold 20. When the push pin 27 is pushed down, the space 29 formed by the cylinder 26 of the pressure holding portion 28 and the push pin 27 communicates with this gap 30. The resin Z injected from the runner 12 in FIG. 1 is injected into the gap 40 between the upper mold 10, the lower mold 20, and the preform 201, and is stored in the space 29. When the push pin 27 is raised, the resin Z stored in the space 29 is injected from the space 29 through the gap 30 into the gap 40 between the upper mold 10, the lower mold 20, and the preform 201.

[0013] FIG. 3 is an explanatory diagram showing a cross-section III-III that does not pass through the pressure holding portion 28 of FIG. 1. In this cross-section, a recess 15 that is recessed along the circumferential surface is formed on the inner circumferential surface 11 of the upper mold 10, and a recess 25 that is recessed along the circumferential surface is formed on the inner circumferential surface 21 of the lower mold 20. A flow media 230, which is a fiber sheet, is disposed in these recesses 15 and 25. Note that there are portions on the inner circumferential surface 11 of the upper mold 10 and the inner circumferential surface 21 of the lower mold 20 that do not have recesses along the circumferential surface, and the cross-section of this portion is the same as the cross-section excluding the pressure holding portion 28 from FIG. 2.

[0014] FIG. 4 is a plan view of the lower mold 20. A plurality of pressure holding portions 28 are provided along the longitudinal direction at positions sandwiching the preform 201. The plurality of pressure holding portions 28 are communicated by a communication portion 31 that extends in the longitudinal direction. A resin injection gate 32 that is connected to the runner 12 of the upper mold 10 is provided substantially at the center of the communication portion 31. The resin Z injected from the runner 12 passes through the communication portion 31 from the resin injection gate 32 and is stored in the space 29 between the cylinder 26 of the plurality of pressure holding portions 28 and the push pin 27. Further, the resin Z is injected from the space 29 through the gap 30 between the inner circumferential surface 11 of the upper mold 10 and the inner circumferential surface 21 of the lower mold 20.

[0015] FIG. 5 is an explanatory diagram schematically showing a state in which the preform 201 is disposed in the mold 100. FIG. 6 is an enlarged view of the region X in FIG. 5. A gap 40 is formed between the inner peripheral surface 11 of the upper mold 10 and the fiber layer 204 of the preform 201. Further, a plurality of recesses 15 recessed along the circumference are provided on the inner peripheral surface 11 of the upper mold 10. A flow medium 230 is disposed between the recess 15 and the fiber layer 204 of the preform 201. Note that the flow medium 230 may be disposed in some of the plurality of recesses 15, and it is not necessary for the flow medium 230 to be disposed in all the recesses 15.

[0016] FIG. 7 is an explanatory diagram showing the flow medium. The flow medium 230 is, for example, a knitted fabric formed by knitting nylon fibers 232. The operator may form the flow medium 230 by knitting glass fibers instead of the nylon fibers 232. The interval between the fibers 232 of the flow medium 230 is wider than the interval between the carbon fibers of the fiber layer 204, and since the interval between the fibers 232 is not collapsed by the flow of the resin Z, the resin Z can flow easily. Further, since the resin Z passes between the fibers 232, the flow of the resin Z is less likely to become a turbulent flow and does not become turbulent.

[0017] FIG. 8 is an explanatory diagram showing the manufacturing process of the tank 200. FIG. 9 is an explanatory diagram illustrating a part of the manufacturing process of the tank 200. FIGS. 10 and 11 are explanatory diagrams showing the flow of the resin Z in the region X in FIG. 5. In step S100, the operator prepares the preform 201 by winding the fiber layer 204 around the liner 203 to which the base 210 is attached.

[0018] In step S110, the operator opens the mold 100 and disposes the preform 201 and the flow medium 230 in the mold 100. Specifically, the operator disposes the flow medium 230 in the recess 25 of the lower mold 20, and then disposes the preform 201. The operator disposes the flow medium 230 in the recess 15 of the upper mold 10, and disposes the upper mold 10 on the lower mold 20 on which the preform 201 is disposed.

[0019] In step S120, the operator closes the mold 100 and clamps the upper mold 10 and the lower mold 20. In step S130, the operator evacuates the inside of the mold 100 from the exhaust passage 22 using a pump.

[0020] In step S140, the operator injects the resin Z into the inside of the mold 100 from the runner 12. At the start of the injection of the resin Z, as shown in FIG. 9, the push pin 27 of the pressure holding portion 28 is pushed down. Therefore, the resin Z is stored in the space 29 formed by the cylinder 26 and the push pin 27 of the pressure holding portion 28. Further, as shown in FIGS. 9 and 10, the resin Z is injected into the gap 40 between the inner peripheral surface 11 of the upper mold 10 and the fiber layer 204 of the preform 201. Similarly, the resin Z is injected into the gap 40 between the inner peripheral surface of the lower mold 20 and the fiber layer 204 of the preform 201.

[0021] In step S150, the operator pushes up the push pin 27 of the pressure holding portion 28 as shown in FIG. 9 to apply pressure holding. The pressure holding is the pressure applied so that the resin Z does not flow back from the resin injection gate 32 until the resin Z in the gate solidifies and a gate seal is formed after the molten resin Z is injected into the mold 100. At this time, due to this pressure holding, the resin Z is impregnated into the fiber layer 204 as shown in FIG. 10.

[0022] In step S160, the operator stops the injection of the resin Z. During this time, the operator may continue to apply pressure holding by the push pin 27.

[0023] In step S170, the operator heats the mold 100 to cure the resin Z. The resin impregnated into the fiber layer 204 cures while containing the fibers of the fiber layer 204, and the resin Z on the inner peripheral surface 11 of the mold 100 cures while containing the flow media 230. That is, the fibers 232 forming the flow media 230 and the cured resin Z function as a fiber reinforced resin layer.

[0024] In step S180, the operator opens the mold 100 and takes out the tank 200. FIG. 11 is an enlarged cross-sectional view of the tank 200 in the region X of FIG. 5. The layers of the tank 200 are four layers, namely, from the inner layer side, the liner 203, the fiber-reinforced resin layer 204Z, the resin layer ZZ, and the fiber-reinforced resin layer 230Z. The fiber-reinforced resin layer 204Z is a layer in which the fiber layer 204 is impregnated with resin and cured. The resin layer ZZ is a layer in which only the resin Z is cured. The fiber-reinforced resin layer 230Z is a layer in which the flow media 230 is impregnated with resin and cured.

[0025] FIG. 12 is an explanatory diagram showing the flow of resin in the region X of FIG. 5 when the flow media 230 is not disposed in the recess 15. In step S140 of FIG. 8, when the resin Z is injected, as shown in FIG. 12, the fibers of the fiber layer 204 in the recess 15 are lifted and floated and disturbed by the flow of the resin Z. Further, since the interval between the fibers in the fiber layer 204 is narrow, the resin Z is difficult to flow due to the obstruction of the lifted fiber layer 204. In the present embodiment, as shown in FIG. 11, the flow media 230 suppresses the floating and disturbance of the fibers of the fiber layer 204 when the resin Z is injected, and facilitates the flow of the resin Z.

[0026] As described above, in the present embodiment, the operator opens the mold 100, disposes the flow media 230, which is a fiber sheet woven in a mesh pattern, in the recesses 15 and 25 of the inner peripheral surfaces 11 and 21, and disposes the preform 201. The flow media 230 presses the fiber layer 204 of the preform 201 so as not to float. As a result, when the resin Z is injected, the fibers forming the fiber layer 204 of the preform 201 are less likely to float or be disturbed. As a result, good resin impregnation property to the fiber layer 204 can be ensured. Further, the inhibition of the flow of the resin Z by the fibers of the floating fiber layer 204 can be suppressed. Since the flow media 230 is disposed in the recesses 15 and 25, it does not move in the longitudinal direction by the resin Z when the resin Z is injected. Further, since the fiber-reinforced resin layer 230Z having the flow media 230 as fibers is formed outside the resin layer ZZ, the strength of the tank 200 can be improved.

[0027] In this embodiment, after injecting the resin Z, the operator applied pressure holding using the push pin 27 to impregnate the fiber layer 204 with the resin Z. However, the timing of stopping the injection of the resin Z and the timing of applying pressure holding by the push pin 27 can be appropriately changed.

[0028] FIG. 13 is an example of a graph showing the pressure applied to the liner 203 and the pressure of the resin during the manufacture of the tank 200. In this example, the operator starts injecting the resin Z into the mold 100 at time 0. After the resin Z is almost injected, the operator moves the push pin 27 to apply pressure holding. At this time, the operator may perform differential pressure control to control the moving amount of the push pin 27 so that the differential pressure between the pressure of the resin Z and the internal pressure of the liner 203 becomes constant.

[0029] In this embodiment, the operator opens the mold 100 and arranges the flow media 230, which is a fiber sheet woven in a mesh pattern, in the recesses 15 and 25 on the inner circumferential surfaces 11 and 21. However, the flow media 230 may be arranged over the entire inner circumferential surfaces 11 and 21. Since the flow media 230 presses down so that the fiber layer 204 of the preform 201 does not float, it is less likely that the fibers forming the fiber layer 204 of the preform 201 will float or become disordered during the injection of the resin Z. As a result, good resin impregnation property into the fiber layer 204 is ensured. In addition, it is possible to suppress the fibers of the floating fiber layer 204 from causing exclusion of the flow of the resin Z.

[0030] In this embodiment, the recesses 15 and 25 on the inner circumferential surfaces 11 and 21 are recessed along the circumferential direction. However, in addition to the recess along the circumferential direction, they may be recessed along the longitudinal direction (axis O direction). It becomes easier to move the resin Z along the recess in the longitudinal direction.

[0031] The present disclosure is not limited to the above-described embodiments, and can be implemented in various configurations without departing from the gist thereof. For example, the technical features of the embodiments corresponding to the technical features in each form described in the summary of the invention can be appropriately replaced or combined in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be appropriately deleted.

Description of Reference Numerals

[0032] 10... upper mold, 11... inner peripheral surface, 12... runner, 13... gap, 15... recess, 20... lower mold, 21... inner peripheral surface, 22... exhaust passage, 23... gap, 25... recess, 26... cylinder, 27... pin, 28... pressure holding portion, 29... space, 30... gap, 31... communication portion, 32... resin injection gate, 40... gap, 100... mold, 200... tank, 201... preform, 203... liner, 204... fiber layer, 204Z... fiber reinforced resin layer, 210... base, 230... flow media, 230Z... fiber reinforced resin layer, 232... fiber, 250... support portion, Z... resin, ZZ... resin layer

Claims

【Claim 1】 A method for manufacturing a tank, comprising: preparing a preform having a liner and a fiber layer disposed outside the liner; opening a mold for impregnating the fiber layer of the preform with resin, disposing the preform inside the mold, and disposing a fiber sheet woven in a mesh pattern between the inner peripheral surface of the mold and the preform; after closing the mold, injecting resin between the inside of the mold and the preform; comprising: the step of disposing the fiber sheet includes a step of disposing the fiber sheet in a plurality of recesses formed by being recessed along the circumference on the inner peripheral surface of the mold; the step of injecting the resin after closing the mold, injecting the resin into the gap between the inside of the mold and the preform, and having a pressure holding part having a cylinder and a push pin, and injecting the resin into the space formed between the inside of the mold and the push pin by pushing down the push pin of the pressure holding part in communication with the gap; after injecting the resin into the gap and the space, pushing up the push pin to extrude the resin in the space into the gap; A method for manufacturing a tank.

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