METHOD FOR PRODUCE A FIBER-REINFORCED RESIN MOLDED BODY AND DEVICE FOR THERETO

Abstract

Method for producing a fiber-reinforced resin molded body (4), comprising forming a preform (2) containing a fiber layer on an outer surface of a lining, impregnating the fiber layer of the preform (2) with resin (3) and curing the resin (3), comprising: a step to prepare a mold (10) with a sprue (16a, 16b) for pouring resin (3) into a cavity (9), wherein the resin (3) comprises a thermosetting resin (3); a step to place the preform (2) in the cavity (9); and a step to pour resin (3) into the cavity (9) through the sprue (16b); characterized by the fact that in the mold (10) a cutting core (17) is arranged which is movable relative to the sprue (16b) in order to cut the resin (3) in the sprue (16b), and that the procedure further shows: a step to stop the pouring of the resin (3) into the cavity (9) to harden the resin (3), and to heat the cutting core (17) to a higher temperature than that of the mold (10); a step to cut the resin (3) in the sprue (16b) by moving the cutting core (17) relative to the sprue (16b) when a viscosity of a portion of the resin (3) in the sprue (16b) at a position of the cutting core (17) is within a predetermined range; and a step to demold the preform (2) while the mold (10) is opened after the curing of the resin (3) impregnated in the preform (2) has ended, wherein In the step of cutting the resin (3) in the sprue (16b), a portion of the resin (3) in the sprue (16b) is cut by the cutting core (17); and In the step of demolding the preform (2) when opening the mold (10) a shear is created between a part of the resin (3) in the sprue (16b) near the cavity (9) with respect to the cutting core (17) and a part of the resin (3) in the sprue (16b) opposite the cavity (9) with respect to the cutting core (17), and a remaining part of the resin (3) in the sprue (16b) is cut.

Description

BACKGROUND Technical area

[0001] The present invention relates to methods for producing fiber-reinforced resin molded bodies, such as a high-pressure tank reinforced with fibers, and to manufacturing devices for this purpose. Technical background

[0002] Fuel cell vehicles comprise a high-pressure tank (hereinafter referred to simply as the tank) in which fuel gas such as natural gas or hydrogen gas is stored. Such a high-pressure tank is manufactured as a fiber-reinforced resin molded body, comprising a hollow liner with gas barrier properties as its core element and carbon fiber reinforced plastic or glass fiber reinforced plastic (hereinafter collectively referred to as the fiber-reinforced resin layer) encasing the liner. For lighter weight, a hollow resin container is typically used as the liner.

[0003] High-pressure tanks are typically manufactured using the filament winding (FW) process and the resin transfer molding (RTM) process. For example, JP 2019-056 415 A discloses a method for manufacturing a high-pressure tank using the RTM process. In this manufacturing process, a preform is placed in a mold. The preform has a liner that defines the interior of the high-pressure tank and a fiber layer formed on the outer surface of the liner. The preform is then rotated circumferentially around its central axis within the mold, while resin is injected from a sprue towards the preform in the mold. SUMMARY

[0004] In such a high-pressure tank manufacturing process, the injection point must be cut off after the resin impregnated into the high-pressure tank (or its fiber layer) has cured in the mold to remove the excess resin (see, e.g., JP 2019-081310 A). In the current process, the formed high-pressure tank is first removed from the mold, and then the injection point is cut off using a laser or a water jet. However, this method can introduce foreign matter, such as burnt resin produced by the laser or water content generated by the water jet, into the high-pressure tank, leading to a reduction in its strength. Furthermore, the post-processing with the laser or water jet can require investment and time, increasing costs.At the same time, variations in processing time depending on the high-pressure tank can lead to variations in the cured state of the high-pressure tank, which in turn leads to variations in the tank's performance.

[0005] A method for injection molding hollow plastic parts, in which at least one cavity of the part is formed by removing an inner section of the plastic mass from the mold cavity of an injection mold using gas pressure via a sprue of the injection mold, and the opening thus formed in the part is then closed, wherein, after removal, plastic mass is forced back into the sprue and partially into the cavity from a blind channel connected to the sprue by means of a power-operated ram before the part is removed from the injection mold, is the subject of DE 10 2007 001 756 A1. DE 10 2018 122 957 A1 also discloses a method and a device for producing a fiber-reinforced resin molded body according to the preamble of the independent claims.

[0006] In view of the problems mentioned above, it is an object of the present invention to provide a method for producing a fiber-reinforced resin molded body that is suitable for effectively increasing the strength of a fiber-reinforced resin molded body, such as a high-pressure tank, and a manufacturing device for this purpose.

[0007] According to one aspect of the present invention, a method for producing a fiber-reinforced resin mold body is disclosed for forming a preform containing a fiber layer on an outer surface of a lining, impregnating the fiber layer of the preform with resin, and curing the resin. The method comprises: a step for preparing a mold with a sprue for pouring resin into a cavity, wherein the resin comprises a thermosetting resin, and a cutting core is arranged therein, the cutting core being movable relative to the sprue to cut the resin in the sprue; a step for placing the preform in the cavity; a step for pouring resin into the cavity through the sprue; a step for stopping the pouring of the resin into the cavity to cure the resin, and for heating the cutting core to a higher temperature than that of the mold.A step to cut the resin in the sprue by moving the cutting core relative to the sprue when the viscosity of a portion of the resin in the sprue at a position of the cutting core is within a predetermined range; and a step to demold the preform while the mold is opened after the resin impregnated in the preform has finished curing. In the step to cut the resin in the sprue, a portion of the resin in the sprue is cut by the cutting core. In the step to demold the preform while opening the mold, shearing is created between a portion of the resin in the sprue near the cavity with respect to the cutting core and a portion of the resin in the sprue opposite the cavity with respect to the cutting core, and a remaining portion of the resin in the sprue is cut.

[0008] In some embodiments, at a time predetermined from a relationship between a curing time and a viscosity of the resin, it is determined that the viscosity of the portion of the resin in the sprue at the position of the cutting core lies within a predetermined range.

[0009] In some embodiments, the process includes, after the demolding step of the preform, a post-curing step in which the preform is heated to a higher temperature than the temperature of the mold.

[0010] In some embodiments, the heating temperature of the cutting core is higher than the temperature of the mold and lower than the heating temperature in the post-curing step.

[0011] In some embodiments, the mold comprises a first mold and a second mold; and in the step of placing the preform in the cavity, the preform is positioned between the first mold and the second mold to define a first gap between the first mold and the preform and a second gap between the second mold and the preform, the second gap being larger than the first gap, the method further comprising, in the step of pouring resin into the cavity through the sprue, a step of bringing the second mold close to the preform in order to fill the cavity with the resin under pressure.

[0012] According to another aspect of the present invention, an apparatus for producing a fiber-reinforced resin molded part is disclosed, for forming a preform with a fiber layer on an outer surface of a lining, for impregnating the fiber layer of the preform with resin, and for curing the resin, and the apparatus comprises: a mold with a sprue for pouring resin into a cavity, wherein the resin comprises a thermosetting resin, and a cutting core is arranged therein, the cutting core being movable relative to the sprue to cut the resin in the sprue; a heating mechanism configured to heat the cutting core; a cutting core drive mechanism configured to drive the cutting core; a mold drive mechanism configured to drive the mold in one direction to open and close the mold;a resin pouring mechanism configured to pour the resin through the sprue into the cavity; and a control device configured to control operating states of the heating mechanism, the cutting core drive mechanism, the mold drive mechanism, and the resin pouring mechanism, wherein the control device is configured to control the mold drive mechanism to place the preform in the cavity; to control the resin pouring mechanism to pour resin through the sprue into the cavity; to control the resin pouring mechanism to stop pouring the resin into the cavity to allow the resin to cure; and to control the heating mechanism to heat the cutting core to a higher temperature than the mold;to control the cutting core drive mechanism to cut the resin in the sprue by moving the cutting core relative to the sprue when the viscosity of a portion of the resin in the sprue at a position of the cutting core is within a predetermined range;and to control the mold drive mechanism to demold the preform while the mold is opened after the resin impregnated in the preform has finished curing. The mold comprises a first mold and a second mold and has a pressure element, wherein the pressure element forms part of the sprue at a position in the sprue opposite the cavity with respect to the position of the cutting core and is integrally movable with the second mold and movable relative to the first mold, and wherein the control device is configured to control the cutting core drive mechanism to move the cutting core relative to the sprue to cut part of the resin in the sprue;and, when the mold is opened, to control the mold drive mechanism to sandwich a portion of the resin in the sprue opposite the cavity with respect to the cutting core between the second mold and the pressure element, in order to create a shear between a portion of the resin in the sprue near the cavity with respect to the cutting core and a portion of the resin in the sprue opposite the cavity with respect to the cutting core, and to cut a remaining portion of the resin in the sprue.

[0013] In some embodiments, the control device determines, at a time predetermined from a relationship between a curing time and a viscosity of the resin, that the viscosity of the portion of the resin in the sprue at the position of the cutting core lies within a predetermined range.

[0014] In some embodiments, the device further includes a curing oven to carry out a post-curing step in which the preform is heated to a higher temperature than the temperature of the mold after demolding.

[0015] In some embodiments, the heating temperature of the cutting core is higher than the temperature of the mold and lower than the heating temperature in the post-curing step.

[0016] In some embodiments, the mold comprises a first mold and a second mold; and the control device is configured to control the mold drive mechanism to position the preform between the first mold and the second mold to define a first gap between the first mold and the preform and a second gap between the second mold and the preform, the second gap being larger than the first gap; to control the resin pouring mechanism to pour resin through the sprue into the cavity; and to control the mold drive mechanism to bring the second mold close to the preform to fill the cavity with resin under pressure.

[0017] According to one aspect of the present invention, when using a cutting core heated to a higher temperature than the mold, the curing of the resin section to be cut is facilitated, and the resin section is cut by the cutting core. This configuration can perform the gate or cutting of the injection point without generating foreign matter and can also allow the resin to cure stably, thereby increasing the strength of the fiber-reinforced resin molded part, such as a high-pressure tank.

[0018] Furthermore, the post-curing step can increase the strength of the fiber-reinforced resin molded part, e.g., a high-pressure tank, and performing the gate in the mold can suppress the temperature change in the product before post-curing, thereby effectively increasing the strength and quality of the fiber-reinforced resin molded part, e.g., a high-pressure tank.

[0019] Furthermore, by adjusting the temperature of the cutting core within a predetermined range, it is possible to obtain an excellent cutting surface in the part of the resin to be cut, thereby effectively increasing the strength of the fiber-reinforced resin molded body, such as a high-pressure tank. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a vertical cross-sectional view of a manufacturing device for a high-pressure tank (fiber-reinforced resin molded body) according to one embodiment; Fig. Figure 2 is a top view of a lower form of the manufacturing device for a high-pressure tank (fiber-reinforced resin mold body) in which an upper form has been removed, according to the embodiment; Fig. Figure 3 is a flowchart of a process for manufacturing a high-pressure tank (fiber-reinforced resin molded body) according to the embodiment; Fig. Figure 4 is a vertical cross-sectional view of the manufacturing device of a high-pressure tank, showing a step for placing the preform and a step for vacuum degassing according to the embodiment; Fig. Figure 5 is a vertical cross-sectional view of the manufacturing device for a high-pressure tank, showing a resin casting step according to the embodiment; Fig. Figure 6 is a vertical cross-sectional view of the manufacturing device for a high-pressure tank, showing a step towards complete tightening according to the embodiment; Fig. Figure 7 is a vertical cross-sectional view of the manufacturing device for a high-pressure tank, showing a resin casting stop and the step for high-temperature heating of the cutting core according to the embodiment; Fig. Figure 8 is a vertical cross-sectional view of the manufacturing device for a high-pressure tank, showing a step for lifting the cutting core according to the embodiment; Fig. Figure 9 is a vertical cross-sectional view of the manufacturing device for a high-pressure tank, showing a resin curing step according to the embodiment; Fig. Figure 10 is a schematic diagram showing the relationship between curing time and viscosity of the resin (epoxy resin); and Fig. Figure 11 is an enlarged vertical cross-sectional view of a main part to illustrate an example of a resin cutting configuration in a sprue. DETAILED DESCRIPTION

[0020] In the following, an embodiment of the present invention is described with reference to the accompanying drawings.

[0021] The following describes a high-pressure tank for fuel cell vehicles, which is an example of a fiber-reinforced resin molded article or resin molded body. The fiber-reinforced resin molded body to which the present invention is applied is not limited to the high-pressure tank for fuel cell vehicles. The shape, material, etc., of the lining and the preform or preform of the fiber-reinforced resin molded body are also not limited to the illustrated example.

[0022] The RTM process involves wrapping carbon fibers multiple times (in several layers) around a liner to form a preform with a fiber layer on the outer surface of the liner. This fiber layer is then impregnated with epoxy resin, which is subsequently cured. In this way, the RTM process is used to manufacture a high-pressure fuel cell tank for vehicles, featuring a fiber-reinforced resin layer with carbon fiber and epoxy resin on the outer perimeter of the liner. The liner is a hollow container made of resin (e.g., nylon resin) that defines the interior of the high-pressure fuel tank.

[0023] In such a high-pressure fuel cell vehicle tank, the carbon fiber is thickly laminated, so the resin barely penetrates the inner layer of the carbon fiber and the resin flow end section (i.e., the section where the resin flows onto the preform last, or at the latest when it reaches the preform). That is, the high-pressure fuel cell vehicle tank has carbon fiber that is very thickly laminated (about 10 times thicker than a typical RTM-molded part) to achieve sufficient strength, and it is difficult to impregnate the fiber with resin. Furthermore, increasing the mold temperature to the starting temperature for resin curing, in order to shorten the resin curing time, can significantly increase the viscosity, making it difficult to impregnate the resin flow end section of the high-pressure tank with resin using a large cylindrical mold.Simultaneously, lowering the mold temperature to increase resin impregnation with reduced viscosity can extend the resin's curing time and reduce intermolecular bonds in the epoxy resin. This can lead to a deterioration in the tank's performance.

[0024] In light of the above, if a low mold temperature is set for RTM molding, enabling demolding (removal from the mold), post-curing at a high temperature is necessary to ensure the physical properties. However, if the time and tank temperature change between RTM molding and post-curing, the tank quality and performance may deteriorate.

[0025] If, for example, parts other than the tank product, such as a sprue, gate, etc., are machined after RTM molding, post-processing can require investment and time, leading to increased costs. Simultaneously, if the processing time varies depending on the tank and the tank temperature drops or changes, the tank's curing state can vary, and fluctuations in tank performance can occur, resulting in critical quality problems.

[0026] To avoid this, the present embodiment has the following configuration. [Manufacturing device for a high-pressure tank]

[0027] Fig. 1 and Fig. Figure 2 shows a manufacturing device for a high-pressure tank, which is an example of a fiber-reinforced resin molded body according to one embodiment. Fig. Figure 1 is a vertical cross-sectional view and Fig. Figure 2 is a top view of a lower shape with an upper shape removed.

[0028] A preform 2, serving as an intermediate body for the high-pressure tank to be produced in the present embodiment, comprises a liner and a fiber layer formed on the outer surface of the liner for integration with it. The liner is a hollow resin vessel exhibiting gas barrier properties and defining an interior space of the high-pressure tank. In one example, the fiber layer has a thickness of approximately 10 mm to 30 mm. The fiber layer is formed by repeatedly winding fibers around the outer surface of the liner using a filament winding process.

[0029] Examples of fibers wrapped around the lining include carbon fibers, glass fibers, and aramid fibers. The fibers can be continuous, long, or short. As described later, the fiber (layer) wrapped around the lining is impregnated with resin and cured to form a fiber-reinforced resin layer that covers the perimeter of the lining. Examples of resins include thermosetting resins such as epoxy resins, unsaturated polyester resins, and polyamide resins.

[0030] The manufacturing device 1 is configured to produce a high-pressure tank using the RTM process in order to impregnate the fiber layer of which the preform 2 consists with resin (thermocuring resin) 3 (the reference numeral is e.g. in Fig. 5 shown) and to cure the impregnated resin 3.

[0031] In one example, the manufacturing device 1 comprises a mold 10, which consists of a plurality of molds, such as a lower mold 11 as a fixed mold and an upper mold 12 as a movable mold. Closing this lower mold 11 and upper mold 12 (this can be referred to as mold closure) defines a cavity 9 for the fiber-reinforced resin layer. To position the preform 2 with the fiber layer in the mold 10, the cavity 9 of the mold 10 is enlarged, for example, by the tolerance of the preform 2.

[0032] This embodiment comprises the lower form 11 as a fixed form and the upper form 12 as a movable form (a form that is movable relative to the fixed form). In another embodiment, the upper form 12 can be a fixed form and the lower form 11 can be a movable form, or both the lower form 11 and the upper form 12 can be movable. The form 10 in this embodiment comprises the two parts of the lower form 11 and the upper form 12, which can also be three or more parts.

[0033] In mold 10, the preform 2 is supported by a shaft 25 arranged along the axis of the lining. That is, the shaft 25 represents a support mechanism that supports the preform 2 in mold 10 (in the cavity 9).

[0034] A vacuum degassing tube 15 is embedded in the mold 10 (in the illustrated example, in the lower mold 11). The vacuum degassing tube 15 is connected to a vacuum pump 50. The vacuum pump 50 serves to degas (evacuate) the mold 10 (the cavity 9) via the vacuum degassing tube 15. That is, the vacuum pump 50 and the vacuum degassing tube 15 form a vacuum degassing mechanism for vacuum degassing the mold 10 (the cavity 9).

[0035] A resin pouring tube (which can also be called a resin pouring sprue) 16 is embedded in the mold 10. The resin pouring tube 16 is connected to a resin injector 60. The resin injector 60 pours (supplies) resin 3 (via three sprue openings 14, which will be described later) through the resin pouring tube 16 (which will be described in detail later) into the mold 10 (cavity 9). In one example, the resin 3 is a thermosetting two-component epoxy resin consisting of a base resin and a hardener. The resin injector 60 therefore comprises a resin reservoir 61, a resin container 62, and a pressure device 63 for the base resin; a resin reservoir 66, a resin container 67, and a pressure device 68 for the hardener; and a valve 65 to supply the resin 3, which is a mixture of the base resin and the hardener, to the resin pouring tube 16.

[0036] In this example, the resin casting tube 16 extends from the upper mold 12 towards the lower mold 11. As in Fig. As shown in Figure 2, the lower mold 11 is designed with a main sprue 16a extending to the cavity 9, thus connecting continuously to the resin casting tube 16, and with a plurality of sprues 16b branching off from the main sprue 16a to form sprue openings (resin inlets) 14 that are open to the cavity 9. In this example, three sprue openings 14 are provided. The central sprue opening 14 is located opposite the central section (in the axial direction) of the preform 2, and the sprue openings 14 at the opposite ends are located opposite the opposite end sections (in the axial direction) of the preform 2. It should be noted that the number or size of the sprue channels 16b branching off from the main sprue channel 16a, the opening position or size of the gate openings 14 and the like are not limited to the example shown.

[0037] The resin 3, flowing through the resin pouring tube 16, flows from the main sprue 16a to the three sprue channels 16b. This allows the resin injector 60 to pour (feed) the resin 3 through the resin pouring tube 16, the main sprue 16a, and the sprue channels 16b from the three gate openings 14 into the mold 10 (into the cavity 9). That is, the resin injector 60, the resin pouring tube 16, the main sprue 16a, and the sprue channels 16b form a resin pouring mechanism for pouring the resin 3 into the mold 10 (into the cavity 9).

[0038] In mold 10, a cutting core 17 is arranged as a movable core that moves vertically relative to the sprue channels 16b to cut the resin 3 (this can be referred to as gate cutting or cutting the injection point) after it has flowed through the sprue channels 16b and cured to a predetermined viscosity. In this example, the cutting core 17, with a cutting edge for cutting the resin 3 in the sprue channels 16b, is vertically displaceable within a locating groove 11a that extends vertically near the cavity 9 in the lower mold 11, i.e., near the gate openings 14. In the present embodiment, the cutting core 17 is configured to be heated to a predetermined temperature by a heating mechanism 80 (described later).

[0039] Now, a configuration example for the (complete) cutting of the resin 3 in the sprue channels 16b is presented with reference to Fig. 11 described.

[0040] As seen in the enlarged view of the cross-section of the main part of Fig. As shown in Figure 11, the lower form 11, in addition to the locating groove 11a and the cutting core 17, is provided, for example, with an insertion hole 11b extending downwards from the sprue 16b between the cutting core 17 and the resin casting tube 16, i.e., extending downwards from the upstream section of the sprue 16b relative to the position of the cutting core 17. A pressure pin 19, acting as a pressure element, is arranged to be vertically displaceable within the insertion hole 11b. The pressure pin 19 has an end face (upper end face) that forms part of the sprue 16b and is configured to move together with (integrally with) the upper form 12 and to be vertically movable relative to the lower form 11. It should be noted that the end faces (upper end faces) of the cutting core 17 and the pressure pin 19 in the figure shown in Fig. The 11 shown example is flush with the bottom surface of the sprue channel 16b, but does not have to be flush with the bottom surface of the sprue channel 16b.

[0041] The entire manufacturing process will be described later. The cutting of the resin 3 in the sprue channels 16b is carried out as follows. First, the (uncured) resin 3, which has flowed through the resin pouring tube 16, is injected / poured from the gate openings 14 through the main sprue channel 16a and the sprue channels 16b into the cavity 9 (i.e., the resin pouring step: S206, and the step for complete curing: S207, which are described later). At this point, the end face (upper end face) of the pusher pin 19 forms part of the sprue channels 16b, and the temperature of the cutting core 17 is maintained at the mold temperature.

[0042] After the resin filling into cavity 9 is stopped, the resin 3 is cured, and the heating mechanism 80 heats the cutting core 17 to a high temperature (i.e., the resin filling stop and the step for high-temperature heating of the cutting core: S208, which are described later). At this point, the cutting core 17 is heated from the temperature of mold 10 (approx. 100 °C) to a higher temperature (approx. 130 °C) than the temperature of mold 10.

[0043] After a predetermined time has elapsed (at a point when the portion of resin 3 at the cutting core 17 position has reached a semi-cured state), the cutting core 17 is raised (relative to the sprue channels 16b) to cut the portion of resin 3 in the sprue channels 16b at the cutting core 17 position with the cutting edge of the cutting core 17 (i.e., the cutting core raising step: S209, which is described later). At this point, the cutting core 17 is raised to a position where its cutting edge does not touch the upper mold 12 (or its lower surface) to prevent damage and ensure the durability of the mold 10 (the upper mold 12) and the cutting edge of the cutting core 17. As a result, the portion of resin 3 in the sprue channels 16b is cut off at the position of the cutting core 17, leaving the upper part of it.In other words, the resin 3 in the sprue channels 16b is not yet completely cut off at this stage.

[0044] After the resin has finished curing in cavity 9, mold 10 (the upper mold 12) is opened and the high-pressure tank is removed (i.e., demolding step S211, which is described later). At this point, as the upper mold 12 is lifted relative to the lower mold 11, the pressure pin 19 located in the lower mold 11 is lifted along with the upper mold 12 (integral with the upper mold 12). As a result, the upstream portion of the resin 3 in the gate channels 16b relative to the cutting core 17 (the portion opposite cavity 9 relative to the cutting core 17) is lifted along with the upper mold 12 and the pressure pin 19, while being sandwiched between the upper mold 12 (or its lower surface) and the pressure pin 19 (or its upper end face).Meanwhile, the downstream portion of the resin 3 remains in the sprue channels 16b relative to the cutting core 17 (the portion near the cavity 9 in relation to the cutting core 17) together with the formed high-pressure tank on the lower mold 11. This creates a (vertical) shear between the downstream portion and the upstream portion of the resin 3 in the sprue channels 16b relative to the cutting core 17, and the shear cuts off the upper portion (the remaining portion) of the resin 3 that is not cut by the cutting core 17, thereby completely cutting off the resin 3 in the sprue channels 16b near the cutting core 17.

[0045] It should be noted that the configuration example described above for cutting the resin 3 in the sprue channels 16b is just one example. It goes without saying that in another example, the resin 3 in the sprue channels 16b can be completely cut off with the cutting edge of the cutting core 17.

[0046] Although not shown in the drawings, the manufacturing apparatus 1 of the present embodiment includes a curing oven to carry out a post-curing step in which the high-pressure tank 4 removed from the mold 10 (i.e. the preform 2 after the resin 3 has been impregnated and cured) is heated to a higher temperature (e.g. about 140 °C to 160 °C) than the temperature of the mold 10 (e.g. about 80 °C to 100 °C).

[0047] The manufacturing device 1 comprises: a transfer mechanism 20 for transferring the preform 2 to a predetermined position; a mold drive mechanism 30 for driving the mold 10 (in particular the upper mold 12) in the direction for opening and closing the mold (vertical direction); a temperature controller 40 for regulating the temperature of the mold 10 (lower mold 11, upper mold 12); a cutting core drive mechanism 70 for driving the cutting core 17 in the direction for cutting (vertical direction); and the heating mechanism 80 for heating the cutting core 17.to heat; and the control device 90 as a controller to control the operating state of the entire manufacturing device 1 (in particular the operating states of the transfer mechanism 20, the mold drive mechanism 30, the temperature controller 40, the vacuum pump 50 in the vacuum degassing mechanism and the pressure devices 63 and 68 and the valve 65 of the resin injector 60 in the resin casting mechanism, the cutting core drive mechanism 70, the heating mechanism 80, etc.). [Method for manufacturing a high-pressure tank]

[0048] Fig. Figure 3 is a flowchart illustrating a process for manufacturing a high-pressure tank, which is an example of a fiber-reinforced resin molded body according to the embodiment. Fig. 4 to Fig. Figure 9 shows vertical cross-sectional views, each showing a step for placing the preform and a step for vacuum degassing, a resin pouring step, a step for full tightening, a resin pouring stop and a step for high-temperature heating of the cutting core, a step for lifting the cutting core and a resin curing step. Fig. Figure 10 is a schematic diagram showing the relationship between a curing time and a viscosity of the resin (epoxy resin) to which reference is made when determining a semi-cured state. (Form preparation step: S201)

[0049] First, in the process, the form 10 is prepared, which comprises the lower form 11 and the upper form 12 with the structure described above. As described above, the form 10 (the lower form 11) includes, for example, the cutting core 17, which can be heated to a predetermined temperature by the heating mechanism 80. (Preform preparation step: S202)

[0050] As described above, the process begins with the preparation of the preform 2, in which a fiber layer is formed by wrapping (winding) fibers around the outer surface of the lining. (Mold temperature holding step: S203)

[0051] Next, the procedure causes the control device 90 to control the temperature controller 40 so that the temperature of the mold 10 (lower mold 11, upper mold 12) is maintained at a predetermined temperature. If the resin 3 is a thermosetting resin, this predetermined temperature is equal to or higher than the curing temperature of the resin 3. This predetermined temperature can be set to a low temperature that allows demolding, for example, approximately 80 °C to 100 °C.

[0052] The procedure in this example initially maintains the temperature of mold 10 at or above the curing temperature of resin 3. In another example, the temperature of mold 10 can be maintained initially at a lower temperature than the curing temperature of resin 3, and at a suitable time in a later described step (e.g., after the mold 10 has fully cured), the temperature of mold 10 can be maintained at or above the curing temperature of resin 3. (Step to place the preform: S204)

[0053] Subsequently, the control device 90 controls the transfer mechanism 20 and the mold drive mechanism 30 to place the preform 2 into the mold 10 (i.e., the cavity 9 formed between the lower mold 11 and the upper mold 12) Fig. 1, Fig. 4) In particular, when the upper mold 12 opens, the transfer mechanism 20, under the control of the control device 90, places the preform 2 onto the lower mold 11 (or the section corresponding to the cavity 9 in the lower mold 11). At this point, the shaft 25 supports the preform 2. Subsequently, the mold drive mechanism 30 initiates the mold closure in a state where the cutting core 17 is in a low position and temporarily tightens the upper mold 12 under the control of the control device 90. This temporary tightening is an intermediate state between the open state of the upper mold 12 and the fully tightened state, and in the temporary tightening state, there is a gap between the lower mold 11 and the upper mold 12. As in Fig. As shown in Figure 4, the upper form 12 moves to a position with a gap (second gap) of several mm with the preform 2. This gap (second gap) between the upper form 12 and the preform 2 is larger than a gap (first gap) between the lower form 11 and the preform 2. (Step towards vacuum degassing: S205)

[0054] Next, the control device 90 controls the vacuum pump 50 while maintaining the aforementioned state of temporary tightening (i.e., before completion of the mold closure) in order to degas the mold 10 ( Fig. 4). (Resin casting step: S206)

[0055] After completion of the vacuum degassing process described above, the resin 3 is injected / poured into mold 10 ( Fig. 5) In particular, the control device 90 opens the valve 65, pressurizes the base resin stored in the resin reservoir 62 with the pressure device 63, and pressurizes the hardener stored in the resin reservoir 67 with the pressure device 68 to mix the base resin and the hardener and to produce the (uncured) resin 3. This causes the (uncured) resin 3 to flow through the resin casting tube 16, which extends from the upper mold 12 to the lower mold 11, so that the resin 3 is injected / poured from the sprue openings (in the illustrated example, the three sprue openings on the middle section and the opposite end sections of the preform 2) 14 through the main sprue 16a and the sprue channels 16b towards the preform 2. Since the upper form 12 is temporarily tightened, the resin 3 is mainly injected and poured into the gap (second gap) between the upper form 12 and the (upper surface of the) preform(s) 2. (Step to fully dressing: S207)

[0056] Next, the control device 90 controls the mold drive mechanism 30 to lower the upper mold 12 to the lower end in order to fully close the mold (i.e., bring it closer to the preform 2) and to fully close (fully tighten) the upper mold 12 and the lower mold 11. Fig. 6). This ensures that the filling of the mold 10 with the resin 3 is kept uniform under pressure and enables impregnation with the resin 3 in the lamination of the fiber layer of the preform 2. (Resin casting stop and step to high-temperature heating of the cutting core: S208)

[0057] Then, after the fiber layer is completely impregnated with the resin 3, the process stops pouring the resin 3 into the mold 10 (into the cavity 9) and the resin 3 hardens ( Fig. 7) Simultaneously, the control device 90 controls the heating mechanism 80 to initiate high-temperature heating of only the cutting core 17. The cutting core 17 is heated from the temperature of the mold 10 (e.g., approximately 80°C to 100°C) to a higher temperature (e.g., approximately 120°C to 140°C) than that of the mold 10. This accelerates and facilitates the curing of the portion of the resin 3 in the sprue channels 16b at the position of the cutting core 17. Furthermore, the high-temperature heating of only the cutting core 17, which has a relatively smaller volume than the mold 10, effectively (i.e., in a short time) cures the portion of the resin 3 in the sprue channels 16b at the position of the cutting core 17. (Step to lift the cutting core: S209)

[0058] At a time when the portion of the resin 3 in the sprue channels 16b at the position of the cutting core 17 (hereinafter referred to as the portion of the resin 3 that is not the product) reaches a semi-cured state due to the high-temperature heating of the cutting core 17, the control device 90 controls the cutting core drive mechanism 70 to raise the cutting core 17 and cut the portion of the resin 3 that is not the product ( Fig. 8) The point in time at which the part of the resin 3 that is not the product reaches a semi-cured state can be determined as a predetermined point in time, e.g. based on the in Fig. Figure 10 illustrates the relationship between the curing time and the viscosity of the resin 3. In the "semi-cured state," the viscosity of the resin 3 lies within a predetermined range, and the term "semi-cured state," as used in the present embodiment, refers to the state from the point at which the viscosity begins to temporarily decrease after the start of curing, until the point at which the viscosity reaches approximately 90% of the maximum viscosity upon completion of curing. During this time, the resin 3 can be cut with the cutting core 17 while maintaining the temperature of the cutting core 17 (e.g., approximately 120 °C to 140 °C). (Resin curing step: S210)

[0059] After cutting with the cutting core 17 described above, the process cures the resin 3 in the mold 10 (in the cavity 9) (more precisely, the resin 3 with which the preform 2 is impregnated in the cavity 9) ( Fig. 9) The hardness (viscosity) of the resin 3 is adjusted so that demolding (removal from the mold) is possible. (Demolition step: S211)

[0060] After the resin 3 has finished curing, the control device 90 controls the mold drive mechanism 30 to open the mold 10 (the upper mold 12) in order to remove the formed high-pressure tank 4 (the preform 2 after the resin 3 has impregnated and cured) from the mold 10. In the present embodiment, when the upper mold 12 is opened, the portion of the resin 3 that is not the product is completely cut off (sheared off) (see Fig.11) When the curing of the resin 3 is complete, the high-pressure tank 4 is obtained with the fiber-reinforced resin layer formed on the outer circumference of the lining. (Post-curing step: S212)

[0061] Next, the control device 90 controls the transfer mechanism 20 to convey the formed high-pressure tank 4, removed from mold 10, to a curing oven (not shown) for a post-curing step. The post-curing step heats the high-pressure tank 4 to a higher temperature (e.g., approximately 140 °C to 160 °C) than the temperature of mold 10 (e.g., approximately 80 °C to 100 °C). This increases the intermolecular bonds (accelerating the reaction) in the resin 3 of the high-pressure tank 4 and cures the resin 3 of the high-pressure tank 4 completely until it exhibits stable properties as a product.

[0062] It should be noted that the heating temperature in the post-curing step is higher than the heating temperature of the cutting core 17. In other words, the aforementioned heating temperature of the cutting core 17 (e.g., approximately 120 °C to 140 °C) is higher than the temperature of the mold 10 (e.g., approximately 80 °C to 100 °C) and lower than the heating temperature in the post-curing step (e.g., approximately 140 °C to 160 °C). If, for example, the heating temperature of the cutting core 17 is too high (i.e., higher than or equal to the curing temperature), the resin 3 will begin to partially cure, leading to variations in the cured state in the subsequent resin curing step (S210). In other words, by setting the heating temperature of the cutting core 17 to such a high temperature that the resin 3 is almost completely cured compared to the tank section, it is possible to clearly cut the resin 3 (if the cut surface is not clear, the strength decreases from the cut surface).However, if the resin 3 is fully cured by setting the heating temperature of the cutting core 17 to a much higher temperature, the resin 3 will not be integrated with the tank section (the section of resin 3 becomes a foreign body, and thus the strength decreases from that section onwards).

[0063] As described above, in the production of a high-pressure fuel cell tank using the RTM process, after the epoxy resin has been impregnated and cured in the mold, the remaining parts of the resin that are not part of the product, such as a sprue, injection point, etc., are cut off and post-processed. At this stage, fluctuations in time and tank temperature before the subsequent post-curing step can cause critical quality problems, leading to a deterioration in tank performance.

[0064] In order to control and stabilize the curing conditions (time and temperature) in the RTM process and to integrate the steps by performing the post-processing in the RTM mold, the present embodiment has in the mold the cutting core 17 as a movable core for cutting the part that is not the tank product during the resin impregnation in the RTM step and the heating mechanism 80 for the cutting core, and cuts the part of the resin to be cut while it cures rapidly in the mold, thereby removing the part of the resin that is not the product in the RTM resin impregnation step.

[0065] After the tank (preform 2) is inserted into the mold 10 and the mold is closed, and the resin 3 is subsequently poured, the tank (the fiber layer of the preform 2) is impregnated with the resin 3 in the present embodiment, and the resin 3 is cured. At the point when the curing of the resin 3 begins, the present embodiment initiates high-temperature heating of the cutting core 17 in the section to be cut, facilitating the curing of the portion of the resin 3 to be cut that is not the product. When only the portion of the resin 3 to be cut is partially cured, the present embodiment raises the heated cutting core 17 and cuts the portion of the resin 3 to be cut in the mold. Then, after the curing of the resin 3 is complete and the tank is removed, the present embodiment continuously transfers only the tank to the post-curing step, thereby producing a high-pressure tank.Since the time and temperature do not change before the post-curing step after impregnation of the epoxy resin and curing of the epoxy resin in the mold, the present embodiment can produce a high-pressure tank with a stable curing reaction.

[0066] It should be noted that, since in the present embodiment the entire mold is not heated to a high temperature, the epoxy resin impregnation is not reduced by an increase in viscosity along with the heating, and the present embodiment can cut the part of the resin 3 to be cut, which is not the tank product, in the RTM mold, which enables continuous production of tank products.

[0067] In this way, when a thick tank is formed using RTM impregnation technology, the present embodiment cuts the portion of resin 3 to be cut, which is not part of the tank product, within the mold. This configuration can control and stabilize the curing reaction and also enables continuous production of tank products by integrating the post-processing steps. Thus, the present embodiment can produce a high-pressure tank 4 that achieves improved resin impregnation, quality, and tank performance while simultaneously reducing costs.

[0068] As described above, according to the present embodiment, when using the cutting core 17, which is heated to a higher temperature than that of the mold 10, the curing of the portion of the resin (thermoset resin) 3 to be cut in the sprue channels 16b is facilitated, and the portion of the resin 3 to be cut in the sprue channels 16b is cut by the cutting core 17. This configuration can perform the gate operation without generating foreign matter and also allows the resin 3 to cure stably, thereby increasing the strength of the high-pressure tank (fiber-reinforced resin mold body) 4.

[0069] Furthermore, the post-curing step can increase the strength of the high-pressure tank (fiber-reinforced resin molded body) 4, and the execution of the gate in the mold 10 can suppress the temperature change in the product before post-curing, thereby effectively increasing the strength and quality of the high-pressure tank (fiber-reinforced resin molded body) 4.

[0070] Furthermore, by adjusting the temperature of the cutting core 17 within a predetermined range, the present embodiment can obtain an excellent cutting surface in the part of the resin 3 to be cut in the sprue channels 16b, thereby effectively increasing the strength of the high-pressure tank (fiber-reinforced resin mold body) 4. DESCRIPTION OF REFERENCE MARKS 1 Manufacturing device for a high-pressure tank (fiber-reinforced resin molded body) 2 Preform 3 Harz 4 High-pressure tank (fiber-reinforced resin molded body) 9 Cavity 10 Form 11 Lower form (first form) 11a Fitnut 11b Insertion hole 12 Upper form (second form) 14 Gate opening 15 Vacuum degassing tube (vacuum degassing mechanism) 16 Resin casting tube (resin casting mechanism) 16a Main sprue (resin casting mechanism) 16b sprue runner (resin casting mechanism) 17 cutting core 19 Pressure pin (pressure element) 20 Transfer mechanism 25 wave 30 Form drive mechanism 40 temperature controllers 50 Vacuum pump (vacuum degassing mechanism) 60 Resin injector (resin casting mechanism) 61, 66 resin storage 62, 67 resin containers 63, 68 Printing device 65 valve 70 Cutting core drive mechanism 80 Heating mechanism 90 Control device

Claims

[1] Method for producing a fiber-reinforced resin molded body (4), comprising forming a preform (2) containing a fiber layer on an outer surface of a lining, impregnating the fiber layer of the preform (2) with resin (3) and curing the resin (3), comprising: a step to prepare a mold (10) with a sprue (16a, 16b) for pouring resin (3) into a cavity (9), wherein the resin (3) comprises a thermosetting resin (3); a step to place the preform (2) in the cavity (9); and a step to pour resin (3) into the cavity (9) through the sprue (16b); characterized by , that in the mold (10) a cutting core (17) is arranged which is movable relative to the sprue (16b) in order to cut the resin (3) in the sprue (16b), and that the procedure further shows: a step to stop the pouring of the resin (3) into the cavity (9) to harden the resin (3), and to heat the cutting core (17) to a higher temperature than that of the mold (10); a step to cut the resin (3) in the sprue (16b) by moving the cutting core (17) relative to the sprue (16b) when a viscosity of a portion of the resin (3) in the sprue (16b) at a position of the cutting core (17) is within a predetermined range; and a step to demold the preform (2) while the mold (10) is opened after the curing of the resin (3) impregnated in the preform (2) has ended, wherein In the step of cutting the resin (3) in the sprue (16b), a portion of the resin (3) in the sprue (16b) is cut by the cutting core (17); and In the step of demolding the preform (2) when opening the mold (10) a shear is created between a part of the resin (3) in the sprue (16b) near the cavity (9) with respect to the cutting core (17) and a part of the resin (3) in the sprue (16b) opposite the cavity (9) with respect to the cutting core (17), and a remaining part of the resin (3) in the sprue (16b) is cut. [2] Method for producing a fiber-reinforced resin molded body (4) according to claim 1, wherein at a time which is determined in advance from a relationship between a curing time and a viscosity of the resin (3) it is determined that the viscosity of the part of the resin (3) in the sprue (16b) at the position of the cutting core (17) is within a predetermined range. [3] Method for producing a fiber-reinforced resin molded body (4) according to claim 1, further comprising, after the step of demolding the preform (2), a post-curing step in which the preform (2) is heated to a higher temperature than a temperature of the mold (10). [4] Method for producing a fiber-reinforced resin molded body (4) according to claim 3, wherein a heating temperature of the cutting core (17) is higher than the temperature of the mold (10) and lower than a heating temperature in the post-curing step. [5] Method for producing a fiber-reinforced resin molded body (4) according to claim 1, wherein: the form (10) comprises a first form (11) and a second form (12); and In the step of placing the preform (2) in the cavity (9), the preform (2) is arranged between the first mold (11) and the second mold (12) to define a first gap between the first mold (11) and the preform (2) and a second gap between the second mold (12) and the preform (2), wherein the second gap is larger than the first gap. the procedure continues to exhibit, in the step of pouring resin (3) into the cavity (9) through the sprue (16b), a step to bring the second mold (12) closer to the preform (2) in order to fill the cavity (9) under pressure with the resin (3). [6] Device (1) for producing a fiber-reinforced resin molded body (4), for forming a preform (2) with a fiber layer on an outer surface of a lining, for impregnating the fiber layer of the preform (2) with resin (3), and for curing the resin (3), wherein the device (1) comprises: a mold (10) with a sprue (16b) for pouring resin (3) into a cavity (9), wherein the resin (3) comprises a thermosetting resin (3); a mold drive mechanism (30) configured to drive the mold (10) in one direction to open and close the mold (10); a resin casting mechanism (60) configured to pour the resin (3) through the sprue (16b) into the cavity (9); and a control device (90) configured to control operating states of the mold drive mechanism (30) and the resin casting mechanism (60), wherein the control device (90) is configured to to control the mold drive mechanism (30) to place the preform (2) in the cavity (9); and to control the resin casting mechanism (60) to pour resin (3) through the sprue (16b) into the cavity (9); characterized by , that in the mold (10) a cutting core (17) is arranged which is movable relative to the sprue (16b) in order to cut the resin (3) in the sprue (16b); and that the device (1) further comprises: a heating mechanism (80) configured to heat the cutting core (17); and a cutting core drive mechanism (70) configured to drive the cutting core (17); wherein the control device (90) is configured to control operating states of the heating mechanism (80) and the cutting core drive mechanism (70), wherein the control device (90) is configured to to control the resin casting mechanism (60) to stop the pouring of the resin (3) into the cavity (9) to cure the resin (3), and to control the heating mechanism (80) to heat the cutting core (17) to a higher temperature than the mold (10); to control the cutting core drive mechanism (70) to cut the resin (3) in the sprue (16b) by moving the cutting core (17) relative to the sprue (16b) when the viscosity of a portion of the resin (3) in the sprue (16b) at a position of the cutting core (17) is within a predetermined range; and to control the mold drive mechanism (30) to demold the preform (2) while the mold (10) is opened after the curing of the resin (3) impregnated in the preform (2) has ended, wherein the mold (10) comprises a first mold (11) and a second mold (12) and has a pressure element, wherein the pressure element forms part of the sprue (16b) at a position in the sprue (16b) opposite the cavity (9) with respect to the position of the cutting core (17) and is integrally movable with the second mold (12) and is movable relative to the first mold (11), and the control device (90) is configured to to control the cutting core drive mechanism (70) to move the cutting core (17) relative to the sprue (16b) in order to cut a portion of the resin (3) in the sprue (16b); and, when the mold (10) is opened, to control the mold drive mechanism (30) to sandwich a portion of the resin (3) in the sprue (16b) opposite the cavity (9) with respect to the cutting core (17) between the second mold (12) and the pressure element, in order to generate a shear between a portion of the resin (3) in the sprue (16b) near the cavity (9) with respect to the cutting core (17) and a portion of the resin (3) in the sprue (16b) opposite the cavity (9) with respect to the cutting core (17), and to cut a remaining portion of the resin (3) in the sprue (16b). [7] Device (1) for producing a fiber-reinforced resin molded body (4) according to claim 6, wherein the control device (90) determines at a time which is predetermined from a relationship between a curing time and a viscosity of the resin (3) that the viscosity of the part of the resin (3) in the sprue (16b) at the position of the cutting core (17) is within a predetermined range. [8] Device (1) for producing a fiber-reinforced resin molded body (4) according to claim 6, further comprising a curing oven to carry out a post-curing step in which the preform (2) is heated to a higher temperature than the temperature of the mold (10) after demolding the preform (2). [9] Device (1) for producing a fiber-reinforced resin molded body (4) according to claim 8, wherein a heating temperature of the cutting core (17) is higher than a temperature of the mold (10) and lower than a heating temperature in the post-curing step. [10] Device (1) for producing a fiber-reinforced resin molded body (4) according to claim 6, wherein: the form (10) includes the first form (11) and the second form (12); and the control device (90) is configured to to control the form drive mechanism (30) to place the preform (2) between the first form (11) and the second form (12) to define a first gap between the first form (11) and the preform (2) and a second gap between the second form (12) and the preform (2), wherein the second gap is larger than the first gap; to control the resin casting mechanism (60) to pour resin (3) through the sprue (16b) into the cavity (9); and to control the mold drive mechanism (30) to bring the second mold (12) close to the preform (2) in order to fill the cavity (9) under pressure with the resin (3).

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