Manufacturing method of tank

Abstract

The manufacturing method comprises a first placement process for placing a semi-finished product of a tank before impregnating it with resin into a cavity of a mold, wherein the mold comprises a runner connected to the cavity, an extrusion hole branching from the runner, and an extruder slidably disposed inside the extrusion hole; a first injection process for injecting the resin into the cavity through the runner after the first placement process; a second placement process for placing a coloring agent within the extrusion hole after the first injection process; and a second injection process for injecting the resin into the cavity of the mold through the runner while pushing the extruder toward the runner after the second placement process.

Description

Technology Field

[0001] The technology disclosed in this specification relates to a method for manufacturing a tank. Background Technology

[0002] Japanese Patent Publication No. 2021-167653 discloses a method for manufacturing a tank in which a carbon fiber layer is impregnated with resin. The manufacturing method comprises a process of placing a semi-finished product of the tank, prior to impregnating with resin, into a cavity of a mold, and subsequently injecting the resin into the cavity. The problem to be solved

[0003] If voids, welds, etc., occur on the surface of the resin-impregnated carbon fiber layer, the appearance quality of the finished tank product deteriorates. Furthermore, while it is envisioned to add a painting process to coat the surface of the resin-impregnated carbon fiber layer, the addition of this painting process leads to increased manufacturing costs.

[0004] The present specification provides a technology for achieving both the suppression of deterioration in appearance quality and the suppression of increased manufacturing costs. means of solving the problem

[0005] The present specification discloses a method for manufacturing a tank in which a carbon fiber layer is impregnated with resin. The manufacturing method comprises a first placement process in which a semi-finished product of the tank, prior to impregnating with resin, is placed within a cavity of a mold, wherein the mold comprises a runner connected to the cavity, an extrusion hole branching from the runner, and an extruder slidably disposed within the extrusion hole; a first injection process in which, after the first placement process, the resin is injected into the cavity through the runner; a second placement process in which a coloring agent is placed within the extrusion hole after the first injection process; and a second injection process in which, after the second placement process, the resin is injected into the cavity of the mold through the runner while pushing the extruder toward the runner.

[0006] According to the above configuration, by injecting the resin in two stages, divided into a first injection process and a second injection process, the occurrence of voids, welds, etc., on the surface of the carbon fiber layer can be suppressed. In addition, in the second injection process, the coloring agent inside the extrusion hole is mixed with the resin, thereby coloring the surface of the carbon fiber layer. As a result, a process of coating the surface of the carbon fiber layer is unnecessary. Effects of the invention

[0007] From the above, it is possible to achieve both suppression of appearance quality degradation and suppression of manufacturing cost increase. Brief explanation of the drawing

[0008] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention are described below with reference to the accompanying drawings, in which similar reference numerals indicate similar elements. Figure 1 is a diagram showing the configuration of a tank manufacturing device. Figure 2 is a top view of the lower mold. Figure 3 is a configuration diagram of a manufacturing device in a lift state. Figure 4 is a drawing showing the method of manufacturing a tank. Figure 5 is a drawing showing the method of manufacturing a tank. Figure 6 is a graph showing the trend of pressure within the semi-finished product and cavity of the tank. Specific details for implementing the invention

[0009] Configuration of the manufacturing device (2): FIGS. 1 to 3

[0010] The manufacturing device (2) is a device for manufacturing a tank. The tank is, for example, a high-pressure tank for a fuel cell electric vehicle. The tank has a liner that defines the internal space of the tank and a carbon fiber layer formed on the outer surface of the liner. A resin is impregnated into the carbon fiber layer by the manufacturing device (2).

[0011] The manufacturing device (2) is equipped with a mold (4) on which a semi-finished product (8) in a tank before resin impregnation is placed, and an injector (6) for injecting resin into the mold (4). The mold (4) is composed of a pair of molds (10 and 12) that hold the semi-finished product (8) between them. Specifically, the mold (4) is equipped with an upper mold (10) and a lower mold (12). A cavity (10A) following the upper outer shape of the semi-finished product (8) is formed on the lower surface of the upper mold (10). A cavity (12A) following the lower outer shape of the semi-finished product (8) is formed on the upper surface of the lower mold (12).

[0012] As shown in FIG. 2, a gate (12B), a main runner (12C), and a plurality of sub-runners (12D) are formed on the upper surface of the lower mold (12). In FIG. 2, a symbol is assigned to one of the plurality of sub-runners (12D), and the assignment of symbols to the others is omitted.

[0013] At one end of the gate (12B), a flow path (6A) extending from the injector (6) and penetrating the upper mold (10) is connected. At the other end of the gate (12B), a main runner (12C) extending along the longitudinal direction of the tank is connected. A plurality of sub-runners (12D) branch off from the main runner (12C). The plurality of sub-runners (12D) are connected to the cavity (12A).

[0014] The resin injected from the injector (6) passes through the flow path (6A) and gate (12B) and flows into the main runner (12C). The resin flowing into the main runner (12C) flows into each sub-runner (12D) and flows into the cavity (12A) from each sub-runner (12D).

[0015] An extrusion hole (12E) is formed at the connection point between the main runner (12C) and each sub-runner (12D). The extrusion hole (12E) branches off from the sub-runner (12D) along the depth direction of the cavity (12A). As shown in FIG. 2, the lower die (12) has an equal number of extrusion holes (12E) as the sub-runner (12D). Furthermore, the number of extrusion holes (12E) shown in FIG. 2 is merely an example. The lower die (12) may have fewer extrusion holes (12E) than the sub-runner (12D), or more extrusion holes (12E) than the sub-runner (12D).

[0016] An extruder (12F) is slidably disposed inside each extrusion hole (12E). A piston is formed by the extrusion hole (12E) and the extruder (12F). By pushing the extruder (12F) toward the sub-runner (12D), pressure can be applied to the resin flowing through the sub-runner (12D). Additionally, in FIG. 2, one of the plurality of extrusion holes (12E) and one of the plurality of extruders (12F) are labeled, and the labeling of the others is omitted.

[0017] Additionally, the lower mold (12) is provided with a lift mechanism (14) for lifting the semi-finished product (8) and the upper mold (10) from the lower mold (12). FIG. 3 shows the lifted state in which the lift mechanism (14) has lifted the semi-finished product (8) and the upper mold (10). The lift mechanism (14) can maintain the state of the mold (4) in a lifted state. By the lift mechanism (14), a predetermined gap is formed between the semi-finished product (8) and the cavity (10A) and between the semi-finished product (8) and the inner surface of the cavity (12A). The width of the predetermined gap is, for example, several millimeters.

[0018] Method of manufacturing a tank: FIGS. 4 to 6

[0019] Referring to FIGS. 4 to 6, a manufacturing method for manufacturing a tank in which a carbon fiber layer is impregnated with resin is described. The manufacturing method is realized by controlling a manufacturing device (2). In addition, FIGS. 4 and 5 use a cross-sectional view of the manufacturing device (2) cut along line IV-IV of FIG. 2.

[0020] FIG. 4 illustrates a first batch process S1 and a first injection process S2. In the first batch process S1, the mold (4) is opened, and a semi-finished product (8) is placed in the cavity (12A) of the lower mold (12). Then, mold fastening is performed by pushing the upper mold (10) against the lower mold (12). After that, degassing is performed to bring the cavities (10A and 12A) of the mold (4) close to a vacuum. Also, in each drawing, the illustration of the device for performing degassing is omitted. Also, in the first batch process S1, the extruder (12F) is located at the starting position furthest from the sub-runner (12D).

[0021] After the first batch process S1, the first injection process S2 is executed. In the first injection process S2, the injector (6) begins injecting resin into the mold (4). The resin is injected into the cavities (10A and 12A) through the flow path (6A), gate (12B), main runner (12C), and sub-runner (12D).

[0022] In the first injection process S2, the extruder (12F) is pushed out from the starting position toward the sub-runner (12D) and moves to the end position closest to the sub-runner (12D). By doing so, additional pressure is applied to the resin injected into the cavity (10A and 12A).

[0023] In the first injection process S2, the resin is impregnated into the carbon fiber layer of the semi-finished product (8) in the cavity (10A and 12A). When a predetermined amount of resin is injected, the injector (6) stops the injection of the resin.

[0024] In the first injection process S2, the pressure within the cavity (10A and 12A) is measured. A pressure sensor for measuring the pressure within the cavity (10A and 12A) is placed, for example, on the inner surface of the cavity (10A). Additionally, in a modified example, the pressure sensor may be placed in a space leading to the cavity (10A and 12B), for example, in the extrusion hole (12E).

[0025] FIG. 6 is a graph G1 showing the trend of pressure inside the semi-finished product (8) and a graph G2 showing the trend of pressure inside the cavities (10A and 12B). For graphs G1 and G2, the horizontal axis represents time and the vertical axis represents pressure.

[0026] Timing t1 represents the timing at which injection is started in the first injection process S2. As shown in graphs G1 and G2, with the start of resin injection, both the internal pressure of the semi-finished product (8) and the pressure within the cavities (10A and 12B) increase.

[0027] Timing t2 represents the timing at which injection in the first injection process S2 is stopped. As shown in graph G2, when the injection of the resin is stopped, the pressure in the cavities (10A and 12B) decreases but then rises again. Afterwards, the pressure in the cavities (10A and 12B) reaches a peak value and decreases from the peak value at timing t3. Timing t3 represents the timing at which the curing of the resin begins. Timing t3 is detected using the trend of the pressure sensor's measurement value.

[0028] In this embodiment, when the pressure in the cavities (10A and 12B) drops from a peak value to a predetermined value, the mold (4) is opened. When the mold (4) is opened, the resin in the gate (12B), main runner (12C), and sub-runner (12D) is removed. Then, the second batch process S3 of FIG. 5 is executed. In the second batch process S3, the extruder (12F) is returned from the end position to the beginning position. Then, a coloring agent (16) is placed in the extrusion hole (12E).

[0029] After the second batch process S3, the separation process S4 is executed. In the separation process S4, the mold (4) is closed, and the state of the mold (4) is maintained in a lifted state by the lift mechanism (14). By doing so, a predetermined gap is formed between the semi-finished product (8) and the inner surface of the cavity (10A and 12A). In addition, degassing is also performed in the separation process S4.

[0030] After the separation process S4, the second injection process S5 is executed. In the second injection process, the injector (6) resumes the injection of resin into the mold (4) while pushing the extruder (12F) toward the sub-runner (12D). The resin is mixed with the colorant (16) pushed out by the extruder (12F) as it passes through the sub-runner (12D). The resin mixed with the colorant (16) is injected into the cavity (10A and 12A). The resin mixed with the colorant (16) covers the outer surface of the carbon fiber layer impregnated with resin in the first injection process S2 by means of a predetermined gap formed in the separation process S4.

[0031] Effects of this embodiment

[0032] According to the configuration of the present embodiment, by injecting the resin in two stages, divided into a first injection process S2 and a second injection process S5, the occurrence of voids, welds, etc., on the surface of the carbon fiber layer can be suppressed. In addition, in the second injection process S5, the coloring agent (16) inside the extrusion hole (12E) is mixed with the resin, thereby coloring the surface of the carbon fiber layer. As a result, a process of painting the surface of the carbon fiber layer is unnecessary. From the above, it is possible to achieve both suppression of deterioration in appearance quality and suppression of increased manufacturing costs.

[0033] Corresponding relationship

[0034] A semi-finished product (8) is an example of a “semi-finished product.” A mold (4) and a pair of molds (10 and 12) are examples of a “mold” and a “pair of molds,” respectively. Cavities (10A and 12A) are examples of “cavities.” A main runner (12C) and a sub-runner (12D) are examples of “runners.” An extrusion hole (12E) and an extruder (12F) are examples of an “extrusion hole” and an “extruder,” respectively. A coloring agent (16) is an example of a “coloring agent.”

[0035] The following describes precautions regarding the technology shown in the embodiments. The separation process S4 may not be performed. Additionally, in the first injection process S2, the extruder (12F) may not be moved.

[0036] In addition, the timing for opening the mold after the first injection process S2 may be a timing when conditions other than those based on the trend of the pressure sensor's measurement value are satisfied. For example, said timing may be a timing after a predetermined time has elapsed since the first injection process S2 began.

Claims

Claim 1 A method for manufacturing a tank in which a carbon fiber layer is impregnated with resin, comprising: a first placement process for placing a semi-finished product of the tank before impregnating with the resin into a cavity of a mold, wherein the mold comprises a runner connected to the cavity, an extrusion hole branching from the runner, and an extruder slidably disposed inside the extrusion hole; a first injection process for injecting the resin into the cavity through the runner after the first placement process; a second placement process for placing a coloring agent within the extrusion hole after the first injection process; and a second injection process for injecting the resin into the cavity of the mold through the runner while pushing the extruder toward the runner after the second placement process. Claim 2 A manufacturing method according to claim 1, wherein the mold is composed of a pair of molds that interpose the semi-finished product, and after the first injection process, the method comprises a separation process of separating the pair of molds from each other to form a predetermined gap between the semi-finished product and the inner surface of the cavity. Claim 3 A manufacturing method according to paragraph 2, wherein in the separation process, the pair of molds are separated from each other when the pressure change within the cavity satisfies a predetermined condition. Claim 4 A manufacturing method according to paragraph 3, wherein the above-mentioned predetermined condition is that the pressure decreases by a predetermined value from the peak value after reaching the peak value. Claim 5 A manufacturing method according to claim 1, wherein in the first injection process, the resin is injected into the cavity through the runner while pushing the extruder toward the runner, and in the second batch process, the coloring agent is placed in the extrusion hole after separating the extruder from the runner.

Images