Tank manufacturing method

Abstract

To provide a technology for suppressing deterioration in an appearance quality of a finished tank product.SOLUTION: A tank manufacturing method includes: a placement step of placing a tank member including a hollow member and a fiber layer formed on an outer surface of the hollow member in a mold; a first injection step of injecting a first resin impregnated into the fiber layer and containing a curing agent between an inner surface of the mold and an outer surface of the tank member, after the placement step; a separating step in which an upper mold of the mold is separated from a lower mold of the mold by a predetermined distance, at a timing when a pressure between the inner surface of the mold and the outer surface of the tank member reaches a peak value, and the pressure has decreased from the peak value, after the first injection step; a second injection step of injecting a second resin containing paint between the inner surface of the mold and the outer surface of the tank member, after the separating step; and a pressing step of pressing the upper mold against the lower mold, after the second injection step.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present specification discloses a tank manufacturing method for manufacturing a tank. [Background technology]

[0002] Patent Document 1 discloses a method for manufacturing a tank, which includes the steps of placing a preform including a liner and a fiber layer in a mold, supplying a first resin composition to the fiber layer, moving the upper mold a predetermined distance from the lower mold after the first resin composition has been supplied and changing the mold to an unloaded state, supplying a second resin composition to the fiber layer after the mold has been changed to an unloaded state, and bringing the upper mold closer to the lower mold after the second resin composition has been supplied and changing the mold to a clamped state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-151750 Summary of the Invention [Problem to be solved by the invention]

[0004] This specification provides a technique for suppressing deterioration in the appearance quality of the finished tank. [Means for solving the problem]

[0005] The tank manufacturing method disclosed in this specification includes an arrangement step of arranging a tank member including a hollow member and a fiber layer formed on the outer surface of the hollow member in a mold; a first injection step of injecting a first resin to be impregnated into the fiber layer between the inner surface of the mold and the outer surface of the tank member after the arrangement step, the first resin including a curing agent; a separation step of separating an upper mold of the mold from a lower mold of the mold by a predetermined distance after the first injection step, when the pressure between the inner surface of the mold and the outer surface of the tank member reaches a peak value and the pressure drops from the peak value; a second injection step of injecting a second resin including paint between the inner surface of the mold and the outer surface of the tank member after the separation step; and a pressing step of pressing the upper mold against the lower mold after the second injection step.

[0006] If the second resin mixes with the first resin before the first resin begins to harden, color unevenness, voids, etc. may occur on the surface of the second resin. Color unevenness, voids, etc. cause a decrease in the appearance quality of the finished tank. The inventor discovered that the timing when the pressure between the inner surface of the mold and the outer surface of the tank member reaches a peak and then decreases from the peak value is the timing when the hardening of the first resin begins. According to the above configuration, the separation process is performed and the second resin is injected between the inner surface of the mold and the outer surface of the tank member at the timing when the hardening of the first resin begins. This prevents the second resin from mixing with the first resin before hardening, thereby preventing a decrease in the appearance quality of the finished tank.

[0007] The second resin may include a reinforcing material that enhances adhesion of the second resin to the first resin.

[0008] According to the above configuration, the adhesion of the second resin to the first resin is improved, and deterioration in the appearance quality of the finished tank can be further suppressed.

[0009] Details and further improvements of the technology disclosed in this specification are described in the following "Description of Embodiments of the Invention." [Brief explanation of the drawings]

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0011] (Configuration of tank manufacturing equipment 2; Figure 1) The tank manufacturing apparatus 2 is an apparatus for manufacturing a high-pressure tank for a fuel cell vehicle by impregnating a tank member 10 with resin. The tank member 10 is an intermediate product of the high-pressure tank. The tank member 10 includes a hollow member 12 and a fiber layer 14. The fiber layer 14 is formed by winding fiber around the outer surface of the hollow member 12. The fiber is, for example, carbon fiber.

[0012] The tank manufacturing apparatus 2 includes a mold 26, a hardener tank 30, a pump 32, a first main component tank 40, a second main component tank 42, a switching valve 44, a pump 46, and a mixer 50. The mold 26 includes an upper mold 20 and a lower mold 24. The upper mold 20 and the lower mold 24 are overlapped to form a space that follows the outer shape of the tank member 10. A pressure sensor 22 for measuring the pressure inside the mold 26 is provided on the inner surface of the upper mold 20. The pressure sensor 22 may be provided on the inner surface of the lower mold 24, or multiple pressure sensors 22 may be provided on at least one of the inner surfaces of the upper mold 20 and the lower mold 24.

[0013] The hardener tank 30 stores the hardener. The pump 32 pumps the hardener in the hardener tank 30 to the mixer 50. The pump 32 is installed on a flow path between the hardener tank 30 and the mixer 50.

[0014] The first main agent tank 40 stores the first main agent to be injected into the mold 26 in a first injection step (see S4 in FIG. 3) described below. The first main agent is, for example, an epoxy resin. The first main agent is mixed with a curing agent and hardens through a chemical reaction between the two.

[0015] The second main agent tank 42 stores the second main agent to be injected into the mold in the second injection step (see S8 in FIG. 3) described below. The second main agent is, for example, an epoxy resin. The second main agent includes paint and a reinforcing material described below. The second main agent is mixed with a curing agent and hardens through a chemical reaction between the two.

[0016] The flow path extending from the first main component tank 40 is connected to a switching valve 44. In addition, the flow path extending from the second main component tank 42 is also connected to the switching valve 44. The state of the switching valve 44 is set to either a first state in which the flow path extending from the first main component tank 40 is connected to the pump 46, or a second state in which the flow path extending from the second main component tank 42 is connected to the pump 46.

[0017] The pump 46 pumps the first main component in the first main component tank 40 or the second main component in the second main component tank 42 to the mixer 50. The pump 46 is installed on a path between the switching valve 44 and the mixer 50.

[0018] The mixer 50 mixes the curing agent in the curing agent tank 30 with the first main agent in the first main agent tank 40 or the second main agent in the second main agent tank 42. The mixer 50 pumps the mixed material (for example, a mixture of the first main agent and the curing agent) into the mold 26.

[0019] (Tank manufacturing method: Figures 2 to 4) With reference to FIG. 2, a tank manufacturing method for manufacturing a high-pressure tank by controlling the tank manufacturing apparatus 2 will be described.

[0020] Figure 3 shows steps S2 and S4. In step S2, the tank member 10 is placed inside the mold 26, and mold clamping is performed by pressing the upper mold 20 against the lower mold 24. Then, degassing is performed to bring the space inside the mold 26 (i.e., the space between the inner surface of the mold 26 and the outer surface of the tank member 10) close to a vacuum. Note that in each drawing, the illustration of the device for performing degassing is omitted.

[0021] In the subsequent step S4, primary injection is performed. In primary injection, the state of the switching valve 44 is set to the first state, and the curing agent in the curing agent tank 30 and the first main agent in the first main agent tank 40 are pumped to the mixer 50. Then, the mixed material, i.e., the mixture of the first main agent and the curing agent (hereinafter referred to as "the first mixture"), is pumped into the mold 26. The first mixture flows between the inner surface of the mold 26 and the outer surface of the tank member 10. While the first mixture is curing, the first mixture impregnates the fiber layer 14 of the tank member 10. When a predetermined amount of the first mixture is injected, the primary injection is stopped.

[0022] On the right side of Figure 2, a graph G1 showing the change in pressure inside the hollow member 12 and a graph G2 showing the change in pressure inside the mold 26 are described. For graphs G1 and G2, the horizontal axis represents time and the vertical axis represents pressure.

[0023] Timing t1 indicates the timing when the primary injection starts. As shown by graphs G1 and G2, with the start of the primary injection, the pressure inside the hollow member 12 and the pressure inside the mold 26 increase. In the primary injection, the differential pressure between the pressure inside the hollow member 12 and the pressure inside the mold 26 is controlled.

[0024] Timing t2 indicates the timing when the primary injection stops. As shown by graph G2, with the stop of the primary injection, the pressure inside the mold 26 once decreases but then increases again. After that, the pressure inside the mold 26 reaches a peak value and decreases from the peak value at timing t3. The timing t3 when the pressure inside the mold 26 decreases from the peak value is detected using the change in the measured value of the pressure sensor 22.

[0025] 4 shows steps S6 and S8. Step S6 is executed when it is triggered by detecting timing t3 when the pressure inside the mold 26 drops from its peak value. In step S6, the upper mold 20 is lifted up from the lower mold 24. Specifically, the upper mold 20 is separated from the lower mold 24 by a predetermined distance. This forms a predetermined gap between the inner surface of the mold 26 and the outer surface of the tank member 10.

[0026] In the following step S8, a secondary injection is performed. In the secondary injection, the state of the switching valve 44 is set to the second state, and the curing agent in the curing agent tank 30 and the second main agent in the second main agent tank 42 are pressure-fed to the mixer 50. Then, the mixed material, i.e., the mixture of the second main agent and the curing agent (hereinafter referred to as the "second mixture"), is pressure-fed into the mold 26. The second mixture flows between the inner surface of the mold 26 and the outer surface of the tank member 10. The second mixture is applied around the first mixture.

[0027] In the next step S10, mold clamping is performed again to press the upper mold 20 against the lower mold 24. Then, in step S12, the secondary injection is stopped when a predetermined amount of the second mixture has been injected.

[0028] Although not shown in the drawings, after the second mixture has hardened, the tank member 10 is removed from the mold 26. The fiber layer 14 of the removed tank member 10 is impregnated with the hardened first mixture, and the hardened second mixture is applied around the hardened first mixture. A high-pressure tank is completed by the tank manufacturing method of Figure 2.

[0029] The inventor discovered that the timing t3 in the graph G2 of FIG. 2 (i.e., the timing when the pressure in the mold 26 decreased from the peak value) is the timing when the curing of the first mixture started. For example, a comparative example in which steps S6 and S8 are executed at a timing before the timing t3 is assumed. In this comparative example, the second mixture is injected into the mold 26 before the curing of the first mixture starts. In this case, the second mixture may be mixed with the first resin before curing. If the second mixture and the first mixture are mixed, uneven coloring, voids, etc. may occur on the surface of the second mixture, and the second mixture may cure in this state. Uneven coloring, voids, etc. cause a deterioration in the appearance quality of the finished high-pressure tank.

[0030] According to the configuration of this embodiment, at the timing t3 when the curing of the first mixture starts, lift-up and secondary injection are executed (S6 and S8). It is possible to suppress the second mixture from being mixed with the first mixture before curing, and to suppress a deterioration in the appearance quality of the high-pressure tank.

[0031] (Effect of the reinforcing material; FIG. 5) The second main agent contains a reinforcing material for enhancing the adhesion of the second mixture to the first mixture. The reinforcing material is, for example, a glass microballoon. As shown in FIG. 5, in the secondary injection of step S8, the second mixture 110 is applied to the outer surface of the first mixture 100 that has started curing. Here, voids 102 are generated on the outer surface of the first mixture 100 that has started curing. As the application of the second mixture 110 progresses, the reinforcing material 112 in the second mixture 110 penetrates into the voids 102. In a state where the reinforcing material 112 has penetrated into the voids 102, the second mixture 110 cures. The reinforcing material 112 exerts an anchor effect on the voids 102, and the adhesion of the second mixture to the first mixture is enhanced. Thereby, a further deterioration in the appearance quality of the high-pressure tank can be suppressed.

[0032] The surface of the reinforcing material 112 is coated with a conductive material such as carbon or silver. This eliminates the need to apply a primer separately. In a modified example, the surface of the reinforcing material 112 does not have to be coated with a conductive material.

[0033] (Correspondence) The hollow member 12, the fiber layer 14, and the tank member 10 are examples of a "hollow member," a "fiber layer," and a "tank member," respectively. The mold 26 is an example of a "mold." The first mixture 100, the second mixture 110, and the reinforcing material 112 are examples of a "first resin," a "second resin," and a "reinforcing material," respectively. The tank manufacturing method of FIG. 2 is an example of a "tank manufacturing method." S2, S4, S6, S8, and S10 are examples of a "positioning process," a "first injection process," a "separating process," a "second injection process," and a "pressing process," respectively. Timing t3 in FIG. 2 is an example of a "timing."

[0034] Hereinafter, some points to note regarding the techniques shown in the examples will be described: The second mixture 110 does not necessarily have to contain the reinforcing material 112.

[0035] Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives alone is technically useful. [Explanation of symbols]

[0036] 2: Tank manufacturing equipment 10: Tank parts 12: Hollow member 14: Fiber layer 20: Upper mold 22: Pressure sensor 24: Lower mold 26: Mold 30: Hardening agent tank 32: Pump 40: First main agent tank 42: Second main agent tank 44: Switching valve 46: Pump 50: Mixer 100: First mixture 102: Void 110: Second mixture 112: Reinforcing material G1, G2: Graph t1, t2, t3: Timing

Claims

1. a placement step of placing a tank member including a hollow member and a fiber layer formed on an outer surface of the hollow member in a mold; a first injection step of injecting a first resin to be impregnated into the fiber layer between an inner surface of the mold and an outer surface of the tank member after the placing step, the first resin including a curing agent; a separating step of separating an upper mold part of the mold from a lower mold part of the mold by a predetermined distance when the pressure between the inner surface of the mold and the outer surface of the tank member reaches a peak value and the pressure decreases from the peak value after the first injection step; a second injection step of injecting a second resin containing a paint between the inner surface of the mold and the outer surface of the tank member after the separating step; a pressing step of pressing the upper mold against the lower mold after the second injection step; A tank manufacturing method comprising:

2. The tank manufacturing method according to claim 1 , wherein the second resin includes a reinforcing material that enhances adhesion of the second resin to the first resin.

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