JP2013064429A - Method and apparatus for manufacturing high-pressure gas tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for manufacturing a tank to suppress the variation in a volume fraction of fiber (Vf) in thickness direction of a fiber reinforced resin layer formed on the outer periphery of a liner.SOLUTION: The fiber reinforced resin layer 20 formed on the outer periphery of the liner 10 is subjected to high frequency induction heating in an induction heating coil 220. The induction heating is induced by energization of a high-frequency current to the induction heating coil 220, and in respective resin layer parts in the thickness of the fiber reinforced resin layer 20, rather than the outermost layer part (layer number 1) on an outside surface side of the fiber reinforced resin layer 20, a temperature of a resin layer part (layer number 2) inside the outermost layer part is the highest. As a result, the energization is controlled so that the highest temperature and the temperature of the resin layer part (layer number 2) become the upper limit temperature in the case when the energization by the high-frequency current to the induction heating coil 220 is controlled.

Description

  The present invention relates to a manufacturing method and a manufacturing apparatus for a high-pressure gas tank.

  In recent years, vehicles that are driven by combustion energy of fuel gas or electric energy generated by electrochemical reaction of fuel gas have been developed. Fuel gas such as natural gas or hydrogen is stored in the high-pressure gas tank, and the vehicle May be installed. For this reason, there is a demand for weight reduction of high-pressure gas tanks, and FRP (Fiber) in which a hollow liner is covered with carbon fiber reinforced plastic or glass fiber reinforced plastic (hereinafter collectively referred to as a fiber reinforced resin layer). The adoption of high-pressure gas tanks (hereinafter simply referred to as high-pressure gas tanks) made of Reinforced Plastics (fiber reinforced plastics) is advancing. As the liner, a resin hollow container having gas barrier properties is usually used from the viewpoint of weight reduction.

  In general, when manufacturing such a high-pressure gas tank, a filament winding method (hereinafter referred to as FW method) is adopted. By this FW method, a fiber impregnated with a thermosetting resin such as an epoxy resin is repeatedly wound around the outer periphery of a liner. A reinforced resin layer is used. After that, the thermosetting resin contained in the resin layer is heated and thermoset to produce a high-pressure gas tank in which the liner is covered and reinforced with the fiber reinforced resin layer. Various heating methods such as hot air blowing, heating with an electric heater, or high-frequency induction heating can be used for heating and thermosetting the thermosetting resin, but it is possible to quickly raise the temperature of the thermosetting resin. A technique of induction heating using an induction heating coil that induces high frequency induction heating has been proposed (for example, Patent Document 1).

JP-A-6-335773

  It is known that the tank performance such as strength and durability of the high-pressure gas tank obtained by the FW method depends on the fiber volume content (hereinafter referred to as Vf) in the cured fiber reinforced resin layer on the outer periphery of the liner. This Vf is the ratio of the fiber to the unit volume of the fiber reinforced resin layer, and the Vf increases as the amount of the resin oozing out from the fiber reinforced resin layer before thermosetting increases. And if Vf is high, although the strength increases because the proportion of fibers increases, the amount of resin that bonds and cures the fibers decreases, and there is a concern that the durability may be lowered. For this reason, it is desirable to achieve Vf within a predetermined range while suppressing high Vf in order to achieve both strength and durability that can withstand practical use as a high-pressure gas tank.

  The seepage of the resin that affects Vf can become significant as the viscosity of the resin decreases during induction heating of the fiber reinforced resin layer using the induction heating coil. In other words, the high frequency induction heating method proposed in the above publication can be heated in a short time with higher efficiency than other heating methods, so that the fiber reinforced resin layer is rapidly heated and the viscosity of the resin is also increased. It can be greatly reduced. In addition, since high frequency induction heating is significantly induced in the outermost resin layer closest to the induction heating coil, the temperature rise situation differs in the thickness direction of the fiber reinforced resin layer. And since the difference in the temperature rise state in the thickness direction of the fiber reinforced resin layer can cause a difference in viscosity decrease in the thickness direction of the fiber reinforced resin layer, the variation in Vf in the thickness direction of the fiber reinforced resin layer can be reduced. I could invite you. In the above-mentioned patent document, since there is no consideration about the resin behavior in the process of thermosetting, a method for suppressing the variation in Vf in the thickness direction of the fiber reinforced resin layer has been requested.

  In view of the above-described problems, an object of the present invention is to provide a new tank manufacturing method that can suppress variation in Vf in the thickness direction of a fiber reinforced resin layer formed on the outer periphery of a liner.

  In order to achieve at least a part of the above object, the present invention can be implemented as the following application examples.

[Application Example 1: Manufacturing method of high-pressure gas tank]
A method for manufacturing a high-pressure gas tank, comprising:
A step (a) of preparing a tank intermediate product having a fiber reinforced resin layer formed by winding a fiber impregnated with a thermosetting resin around the outer periphery of a hollow liner serving as a tank container;
(B) a step of inductively heating and thermally curing the fiber reinforced resin layer of the tank intermediate product using an induction heating coil for inducing high-frequency induction heating while rotating the tank intermediate product around the tank axis; With
In the step (b),
The gist is to control energization of the high-frequency current to the induction heating coil on the premise of the presence of a temperature distribution in the resin layer portion in the layer thickness direction of the fiber reinforced resin layer that is heated by receiving the induction heating. .

  In the manufacturing method of the high-pressure gas tank of Application Example 1, when the high-pressure gas tank is manufactured through the steps (a) and (b), the fiber reinforced resin layer is induction-heated using an induction heating coil that induces high-frequency induction heating. In the step (b) of thermosetting, the application of high-frequency current to the induction heating coil is controlled. When the temperature of the fiber reinforced resin layer is increased by receiving the induction heating, the outermost layer portion on the outer surface side of the fiber reinforced resin layer is closest to the induction heating coil, so that the high frequency induction heating by the induction heating coil further proceeds. The resin layer part inside the outermost layer part on the outer surface side receives heat propagation from the outermost layer part in addition to the high frequency induction heating by the induction heating coil in the resin layer part. And although the high frequency induction heating by an induction heating coil progresses more, the outermost layer part is influenced by the heat radiation from the layer surface and the heat propagation to the inner resin layer part. For this reason, temperature distribution occurs in the resin layer portion in the layer thickness direction. In the manufacturing method of the high-pressure gas tank of Application Example 1 described above, energization of the high-frequency current to the induction heating coil is controlled on the premise of the presence of the temperature distribution. For example, the fiber reinforced resin layer is heated by induction heating. In this case, the temperature of the resin layer portion that becomes the maximum temperature can be set to the upper limit temperature in the energization control.

  The manufacturing method of the high-pressure gas tank of Application Example 1 that performs such energization control has a new finding that when the fiber reinforced resin layer is heated by induction heating, temperature distribution occurs in the resin layer portion in the layer thickness direction. Thus, the fiber-reinforced resin layer can be induction-heated until the temperature of the resin layer portion that is the maximum temperature reaches the upper limit temperature when the high-frequency current conduction to the induction heating coil is controlled. If energization control is performed so that the temperature of the resin layer part other than the resin layer part at which the maximum temperature is reached becomes the upper limit temperature, the resin layer part at the maximum temperature becomes higher than the upper limit temperature and the viscosity of the resin decreases. In addition, the seepage associated with this may become noticeable and the Vf may be high. However, according to the manufacturing method of the high-pressure gas tank of Application Example 1 described above, the resin layer portion that has the maximum temperature when the fiber reinforced resin layer is heated by induction heating can be set to the upper limit temperature. Thus, it can be kept within the range corresponding to the upper limit temperature, and the variation in Vf can also be suppressed.

  The manufacturing method of the high-pressure gas tank according to Application Example 1 described above can be configured as follows. For example, in the step (b), the heating upper limit temperature determined by the conditions including the properties of the thermosetting resin is set so that the temperature of the maximum temperature resin layer portion that is the maximum temperature among the resin layer portions in the layer thickness direction is determined. The energization of the high-frequency current to the induction heating coil is controlled so as not to exceed. Since the heating upper limit temperature determined by the conditions including the properties of the thermosetting resin is equivalent to the upper limit temperature in the energization control that can suppress the decrease in the viscosity of the resin and the seepage associated therewith, Accordingly, by preventing the maximum temperature resin layer portion from exceeding the heating upper limit temperature, Vf can be kept in a range corresponding to the heating upper limit temperature, and variation in Vf can be suppressed.

  Further, in the step (b), the correspondence relationship in which the temperature rise state when the fiber reinforced resin layer is heated by receiving the induction heating is associated with each resin layer portion in the layer thickness direction of the fiber reinforced resin layer. Based on the above, the maximum temperature resin layer part is defined as the resin layer part inside the outermost layer part on the outer surface side of the fiber reinforced resin layer. In other words, as described above, the outermost layer portion on the outer surface side of the fiber reinforced resin layer has a higher frequency induction heating by the induction heating coil, but for the reason of transmitting heat to the inner resin layer portion, etc. The resin layer portion is the maximum temperature resin layer portion. In the above aspect, since the maximum temperature resin layer portion is the inner resin layer portion, the temperature of the inner resin layer portion can be set to the upper limit temperature or not to exceed the heating upper limit temperature. Then, the correspondence necessary for setting the maximum temperature resin layer part as the inner resin layer part is grasped in advance by a method such as an experiment or a simulation prior to the tank manufacturing, specifically, induction heating of the fiber reinforced resin layer. Thus, a high-pressure gas tank in which variations in Vf are suppressed can be easily and reliably manufactured.

  Further, in the step (b), when the fiber reinforced resin layer is heated by receiving the induction heating, the temperature of the inner resin layer portion is obtained using the correspondence relationship, and the obtained inner resin is obtained. Depending on the temperature of the resin layer part, control the energization of the high-frequency current to the induction heating coil, or obtain the temperature of the other resin layer part corresponding to the temperature of the inner resin layer part and the corresponding relationship, The temperature of the other resin layer portion thus determined can be substituted for the temperature of the inner resin layer portion to control the application of a high-frequency current to the induction heating coil. In this way, when the temperature of the fiber reinforced resin layer is actually raised, it is possible to perform energization control in accordance with the temperature rise state, so that the effectiveness of suppressing variation in Vf is enhanced.

  Further, in the step (b), the fiber reinforced resin layer can be induction heated by the induction heating coil while radiating heat from the outermost layer portion of the fiber reinforced resin layer. By doing so, the temperature distribution in the thickness direction of the fiber reinforced resin layer can be suppressed through heat radiation from the outermost layer portion, and therefore the effectiveness of suppressing the variation in Vf is enhanced.

[Application Example 2: High-pressure gas tank manufacturing equipment]
An apparatus used for manufacturing a high-pressure gas tank having a fiber-reinforced resin layer that is thermoset by impregnating a thermosetting resin on the outer periphery of a hollow liner serving as a tank container,
A fiber winding means for winding the fiber impregnated with the thermosetting resin before thermosetting around the outer periphery of the liner to form the fiber reinforced resin layer, and obtaining a tank intermediate product;
Thermosetting in which the fiber reinforced resin layer of the rotating tank intermediate product is induction-heated and thermoset using an induction heating coil that induces high-frequency induction heating while rotating the tank intermediate product around the tank axis. Means and
The thermosetting means is
A storage unit that stores a correspondence relationship for each resin layer part in the layer thickness direction of the fiber reinforced resin layer, when the temperature of the fiber reinforced resin layer is increased by receiving the induction heating,
Based on the correspondence relationship, the maximum temperature resin layer part that becomes the maximum temperature among the resin layer parts when the fiber reinforced resin layer is heated, the temperature of the determined maximum temperature resin layer part is, And a control unit that controls energization of a high-frequency current to the induction heating coil so as not to exceed a heating upper limit temperature determined by conditions including properties of the thermosetting resin.

  The manufacturing apparatus of the high-pressure gas tank of Application Example 2 described above is a new tank manufacturing apparatus that can suppress the variation in Vf in the thickness direction of the fiber reinforced resin layer formed on the outer periphery of the liner.

It is explanatory drawing which shows typically the manufacturing process of the high pressure gas tank as one Example of this invention. It is explanatory drawing which shows roughly the structure of FW apparatus 100 used for this manufacturing process. It is explanatory drawing which shows typically the mode of formation of a fiber reinforced resin layer. It is explanatory drawing which shows the inner and outer resin layer site | parts of the fiber reinforced resin layer 20 in the obtained intermediate product tank 12 with the mode of winding of the resin impregnated carbon fiber W. It is explanatory drawing which shows schematic structure of the thermosetting furnace 200 shown in FIG.1 (c) including the arrangement configuration of the induction heating coil 220. FIG. It is explanatory drawing which shows the mode of temperature rising for every resin layer site | part of the thickness direction of the fiber reinforced resin layer 20 in the thermosetting furnace 200 of a present Example with the mode of the measurement. 5 is a flowchart for explaining energization control of a high-frequency current to induction heating coil 220. It is explanatory drawing which shows the mode of the temperature distribution of each resin layer site | part of the fiber reinforced resin layer 20, showing the schematic structure of the thermosetting furnace 200 of a modification.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view schematically showing a manufacturing process of a high-pressure gas tank as an embodiment of the present invention, FIG. 2 is an explanatory view schematically showing a configuration of an FW device 100 used in the manufacturing process, and FIG. It is explanatory drawing which shows the mode of formation of a resin layer typically. In this embodiment, the high-pressure gas tank is a high-pressure hydrogen tank that stores high-pressure hydrogen.

  In the tank manufacturing process of the present embodiment, first, as shown in FIG. 1A, a resin container having a gas barrier property against hydrogen gas is prepared as a liner 10. The liner 10 includes a substantially cylindrical cylinder portion 10a having a uniform radius, and convex dome portions 10b provided at both ends of the cylinder portion. The dome portion 10b is configured by an isotonic curved surface, and has a base 14 for connecting to an external pipe or the like at the apex thereof. In this embodiment, a resin container made of a nylon resin is used as the resin container. A resin container made of another resin may be used as long as it has a gas barrier property against hydrogen gas.

  Next, as shown in FIG.1 (b), the fiber reinforced resin layer 20 is formed in the outer periphery of the liner 10 (fiber reinforced resin layer formation process). In this embodiment, the FW device 100 shown in FIG. 2 is used as the fiber reinforced resin layer forming step. The FW device 100 forms a carbon fiber layer as the fiber reinforced resin layer 20 by repeatedly winding a carbon fiber impregnated with an epoxy resin as a thermosetting resin on the outer periphery of the liner 10. Thereby, the intermediate product tank 12 which has the fiber reinforced resin layer 20 before resin hardening on the outer periphery of the liner 10 is obtained. The configuration of the FW device 100 and the state of fiber winding by the device will be described later.

  Subsequent to the formation of the fiber reinforced resin layer 20, thermosetting is performed. In the thermosetting process, a thermosetting furnace 200 shown in FIG. The thermosetting furnace 200 is configured as a high-frequency induction heating furnace, and supports an intermediate product tank 12 rotatably on a gantry (not shown) via tank pivot shafts 212 at both ends of the tank. The product tank 12 is rotated in the course of heating. In addition, the thermosetting furnace 200 has an induction heating coil 220. The induction heating coil 220 is disposed so as to surround the intermediate product tank 12 that is pivotally supported around the tank axis along the tank longitudinal direction, and the coil winding locus is inclined with respect to the tank axis. The induction heating coil 220 is connected to the high-frequency current generation power source 240, receives a high-frequency current through the control of the high-frequency current generation power source 240 by the control device 230, forms a magnetic flux, and the fiber reinforced resin layer of the intermediate product tank 12. The fiber reinforced resin layer 20 is induction-heated using the carbon fibers 20 (resin-impregnated carbon fibers W) as conductors.

  In the thermosetting process using the thermosetting furnace 200 shown in FIG. 1C, the intermediate product tank 20 in which the fiber reinforced resin layer 20 has been formed prior to the intermediate product tank 12 being carried into the thermosetting furnace 200. 12 is mounted with a tank shaft 212. The tank support shafts 212 are inserted into the caps 14 at both ends of the intermediate product tank 12, and support the intermediate product tank 12 horizontally with the shafts extending from both ends of the tank. After the intermediate product tank 12 is pivotally supported in this way, the thermosetting furnace 200 processes the intermediate product tank 12 in a thermosetting process. In this thermosetting process, the intermediate product tank 12 is rotated at a constant speed together with the tank shaft 212, and the rotation is maintained during the thermosetting process. At the same time as the tank rotation or at a constant speed rotation, the thermosetting furnace 200 controls the control device 230 so that the thermosetting resin (for example, epoxy resin) used for forming the fiber reinforced resin layer 20 is cured. In the induction heating coil 220, a high-frequency current is supplied from the high-frequency current generating power supply 240 to inductively heat the fiber reinforced resin layer 20. Thereby, in the intermediate product tank 12, thermosetting of the thermosetting resin in the fiber reinforced resin layer 20 formed on the outer periphery of the liner 10 occurs. The state of induction heating will be described later.

  After the above-described heat curing of the resin by the heat curing furnace 200, the intermediate product tank 12 that has been heated is subjected to cooling curing. Then, through this cooling curing, a high-pressure hydrogen tank 30 having a fiber reinforced resin layer 20 impregnated with an epoxy resin on the outer periphery of the liner 10 and thermally cured is obtained.

  Here, the order of the formation of the fiber reinforced resin layer 20 by the FW device 100 (FIG. 1B) and the subsequent heat curing of the fiber reinforced resin layer 20 by the thermosetting furnace 200 (FIG. 1C) are performed in order. I will explain later. As illustrated in FIG. 2, the FW device 100 according to the present embodiment includes a creel stand 110, a winding unit 130, a path unit 120 that connects the creel stand 110 and the winding unit 130, and a control unit 150.

  The creel stand 110 includes a plurality of bobbins 112 around which carbon fibers impregnated with an epoxy resin as a thermosetting resin (hereinafter referred to as resin-impregnated carbon fibers W) are wound, and each bobbin 112 using a fixed pulley 114 or the like. The resin-impregnated carbon fiber W is fed out in a predetermined direction. In this embodiment, the resin-impregnated carbon fiber W of a so-called prepreg that has been impregnated with a thermosetting resin is used. The drawn carbon fiber may be impregnated with a thermosetting resin. In addition, it can replace with carbon fiber and can also be used as the fiber of the other material suitable for the filament winding which has appropriate intensity | strength and electroconductivity. In place of the epoxy resin, a thermosetting resin suitable for filament winding having an appropriate bonding strength by thermosetting, for example, a thermosetting resin such as a polyester resin or a polyamide resin can be used.

  From each bobbin 112, the resin-impregnated carbon fiber W is drawn out by the action of the winding part 130, and each resin-impregnated carbon fiber W is guided to the winding part 130 via the path part 120.

  The path portion 120 includes a roller, a guide, and the like, and constitutes a path from the creel stand 110 to the resin-impregnated carbon fiber W from the winding portion 130.

  The winding unit 130 includes an ikuchi guide 132 and a rotation driving device 134 on which the liner 10 is set. The rotational drive device 134 pivotally supports the liner 10 and rotationally drives the liner 10 around its tank axis.

  The ikuchi guide 132 adjusts the winding tension when the resin-impregnated carbon fiber W is wound around the liner 10 while supplying the resin-impregnated carbon fiber W to the outer periphery of the liner 10. Further, it is also involved in properly using hoop winding and helical winding of the resin-impregnated carbon fiber W. In other words, the ikuchi guide 132 is supplied from the path unit 120 by moving in three dimensions: the x-axis which is the major axis direction of the liner 10, the y-axis perpendicular to the x-axis, the z-axis perpendicular to the x-axis and the y-axis. The plurality of resin-impregnated carbon fibers W are bundled and supplied toward the liner 10. The resin-impregnated carbon fiber W is repeatedly wound around the outer circumference of the liner 10 by the movement of the ikuchi guide 132 controlled by the control unit 150 in the three-dimensional direction and the rotation of the liner 10 by the rotation driving device 134. Become. Specifically, as shown in FIG. 3, hoop winding and helical winding are used alternately, and the resin-impregnated carbon fiber W is repeatedly wound around the outer periphery of the dome portion 10b and the cylindrical cylinder portion 10a at both ends of the liner. Turned. As shown in the figure, first, the resin-impregnated carbon fiber W is wound around the region of the substantially cylindrical cylinder portion 10a of the liner 10 by hoop winding, and then folded over the dome portions 10b at both ends of the cylinder portion. The resin-impregnated carbon fiber W is wound by helical winding at an angle corresponding to the position.

  As shown in FIG. 3A, in the cylinder portion 10a, the inner resin layer on the outer periphery side of the liner of the fiber reinforced resin layer 20 is formed by repeating the hoop winding while turning back both ends of the cylinder portion. That is, by rotating the liner 10 around the tank center axis AX and reciprocating the ikuchi guide 132 that is a supply source of the resin-impregnated carbon fiber W along the tank center axis AX at a predetermined speed, the fiber reinforced resin The inner resin layer in the layer 20 is formed by winding with resin-impregnated carbon fibers W. In this hoop winding, the resin-impregnated carbon fiber W from the ikuchi guide 132 forms a winding angle (fiber angle α0: for example, about 89 °) that is almost perpendicular to the tank center axis AX of the cylinder portion 10a. The Then, after adjusting the liner rotational speed and the reciprocating speed of the ikuchi guide 132, the ikuchi guide 132 is reciprocated along the tank center axis AX direction, and the resin-impregnated carbon fiber W is repeatedly wound around the cylinder portion 10a. Turn.

  After such hoop winding is repeated for a predetermined step, the resin-impregnated carbon fiber W is wound repeatedly by switching to the low-angle helical winding shown in FIG. In the low-angle helical winding, the curved outer surface region of the dome portion 10b and the hoop-wound cylinder portion 10a are targets for fiber winding, and the liner 10 extends from the ikuchi guide 132 while rotating around the tank center axis AX. The resin-impregnated carbon fiber W is kept crossed at a low fiber angle αLH (for example, about 11 to 25 °) with respect to the tank center axis AX, and the liner rotational speed and the reciprocating speed of the ikuchi guide 132 are maintained. Adjust. Then, the ikuchi guide 132 is reciprocated along the tank center axis AX direction, and the resin-impregnated carbon fiber W is repeatedly wound spirally so as to hang over the dome portions 10b at both ends of the cylinder portion 10a. In this case, in the dome portions 10b on both sides, the fiber winding direction is turned back and the turn-back position from the tank center axis AX is adjusted in accordance with switching between the forward path and the return path of the ikuchi guide 132. By repeating the wrapping in the winding direction in the dome portion 10b many times, a fiber wound layer in which the resin-impregnated carbon fibers W are stretched in a mesh shape with a low angle fiber angle αLH is formed on the outer surface of the liner 10. Is done. In addition, before performing the above-described low-angle helical winding, the high-angle helical winding in which the resin-impregnated carbon fiber W is wound at a high-angle fiber angle (for example, about 30 to 60 °) with respect to the tank center axis AX. Can also be incorporated.

  After repeating the helical winding for a predetermined step, fiber reinforced by repeating the winding of the resin-impregnated carbon fiber W by the hoop winding described above and the winding of the resin-impregnated carbon fiber W by the helical winding alternately. The resin layer 20 is formed by winding. In this case, if the helical winding is the last, the resin layer by the helical winding becomes the outermost layer side resin layer on the outer surface side in the fiber reinforced resin layer 20. In the above-described hoop winding and helical winding, the control unit 150 performs the rotation speed control of the liner 10 and the winding tension adjustment with the ikuchi guide 132, but is not directly related to the gist of the present invention. Omitted.

  In this way, the hoop winding and the helical winding of the resin-impregnated carbon fiber W are alternately used, whereby the fiber-reinforced resin layer 20 in which the resin-impregnated carbon fiber W is layered on the outer periphery of the liner 10 is formed. And the intermediate product tank 12 which formed the fiber reinforced resin layer 20 in the outer periphery of the liner 10 is obtained through winding of the resin impregnation carbon fiber W by FW method (refer FIG.1 (b)). FIG. 4 is an explanatory view showing the inner and outer resin layer portions of the fiber reinforced resin layer 20 in the obtained intermediate product tank 12 together with the winding state of the resin-impregnated carbon fiber W.

  As shown in the drawing, the fiber reinforced resin layer 20 formed on the outer surface of the liner 10 includes a resin layer portion of the resin-impregnated carbon fiber W by hoop winding and a resin-impregnated carbon fiber W by helical winding from the outer peripheral side of the liner 10. Resin layer portions are alternately laminated. In the figure, for the sake of illustration, each resin layer portion includes a single resin-impregnated carbon fiber W. However, as described above, each resin layer is impregnated with hoop winding and helical winding. By winding the carbon fiber W, the plurality of resin-impregnated carbon fibers W are overlapped by hoop winding and helical winding. Then, by alternately switching between the hoop winding and the helical winding described above, the innermost resin layer portion on the outer peripheral side of the liner 10 becomes a fiber winding layer by the hoop winding shown in FIG. It is about 89 ° as described above. Since the outer resin layer portion is switched from the hoop winding to the low-angle helical winding, the fiber winding layer is formed by the low-angle helical winding shown in FIG. It becomes about 11-25 degrees. Hereinafter, the orientation of the fiber is switched for each layer.

  In FIG. 4, since the tank including the tank center axis AX is viewed in a longitudinal section, the resin-impregnated carbon fiber W is a fiber in each resin layer portion where the fiber orientation is about 89 ° based on hoop winding. The cross-sectional view is a substantially circular shape cut so as to intersect. On the other hand, the resin-impregnated carbon fibers W are viewed in cross-section in a rectangular shape cut along the fiber longitudinal direction at each resin layer portion of about 11 to 25 degrees based on helical winding with a low angle of fiber orientation. In the present embodiment, the fiber wound layer by hoop winding and the fiber wound layer by helical winding that overlaps with this are regarded as one resin layer portion. Therefore, in FIG. 4, the fiber reinforced resin layer 20 is the outermost surface on the outer surface side. The five resin layer parts are shown from the outer layer part to the liner outer peripheral side.

  Next, the thermal curing of the fiber reinforced resin layer 20 having the resin layer configuration as shown in FIG. FIG. 5 is an explanatory diagram showing a schematic configuration of the thermosetting furnace 200 shown in FIG. 1C including the arrangement configuration of the induction heating coil 220.

  As shown in the figure, in the thermosetting furnace 200 of this embodiment, as described above, the intermediate product tank 12 is surrounded around the tank axis along the tank longitudinal direction as described above, and the plan view of FIG. It is wound so that the distance from the outer surface of the fiber reinforced resin layer 20 is substantially the same in the cylinder portion 10a and the dome portion 10b when viewed from the direction. At this time, the induction heating coil 220 does not interfere with a tank support shaft 212 (see FIG. 1) that supports the intermediate product tank 12 and has a coil winding locus inclined with respect to the tank shaft.

  In addition, the thermosetting furnace 200 includes a control device 230 and a temperature sensor 242. The temperature sensor 242 is configured to detect the outer surface temperature of the fiber reinforced resin layer 20 in a non-contact manner, and outputs the detected temperature to the control device 230. The control device 230 is configured as a microcomputer including a CPU, a RAM, and a ROM therein, and the computer program stored in the ROM is expanded and executed in the RAM, so that the induction heating coil 220 is supplied from the high-frequency current generation power supply 240. Controls the application of high-frequency current to the. This energization control is performed by the control device 230 in accordance with the tank constant speed rotation after the intermediate product tank 12 is set in the thermosetting furnace 200. When the induction heating coil 220 is energized with a high-frequency current from the high-frequency current generation power supply 240, the induction heating coil 220 generates a magnetic flux that penetrates the fiber reinforced resin layer 20 of the intermediate product tank 12 that is horizontally supported and rotates around the tank axis. . Since the resin-impregnated carbon fiber W constituting the fiber reinforced resin layer 20 intersects with the magnetic flux generated by the induction heating coil 220, an eddy current is induced, and heat is generated due to the resistance inherent to the carbon fiber. High frequency induction heating of the curable resin. This high frequency induction heating occurs in each resin layer portion of the fiber reinforced resin layer 20 shown in FIG.

  Next, the state of energization control by the control device 230 will be described together with the temperature rise state of the fiber reinforced resin layer 20. FIG. 6 is an explanatory view showing a state of temperature rise for each resin layer portion in the thickness direction of the fiber reinforced resin layer 20 in the thermosetting furnace 200 of the present embodiment, together with the state of the measurement.

  First, in order to measure the temperature rise state of each of the five resin layer portions from the outermost layer portion on the outer surface side of the fiber reinforced resin layer 20 to the liner outer peripheral side, a thermocouple was embedded in the resin layer portion of each layer. In FIG. 6, this thermocouple is indicated by a square in the figure, and when switching from the hoop winding to the helical winding described in FIG. 3, the thermocouple is mounted and the helical winding is continued as it is. Thereby, the intermediate product tank 12 for measuring the temperature rise state in which a thermocouple is embedded in each resin layer portion is obtained. Next, the intermediate product tank 12 for measurement is subjected to high-frequency induction heating in the thermosetting furnace 200 in accordance with a normal tank manufacturing process procedure. The high-frequency induction heating by the thermosetting furnace 200 is already performed at each resin layer portion of the fiber reinforced resin layer 20 when the control device 230 of the thermosetting furnace 200 supplies high-frequency current to the induction heating coil 220 from the high-frequency current generation power supply 240. It happens as described. And the measurement temperature of each resin layer site | part during induction heating was plotted, and the relationship between the heating time shown in FIG. 6 and the temperature rising condition for each layer, and the relationship between the layer depth and temperature were obtained. The graph of FIG. 6 represents the temperature situation seen in the intermediate product tank 12 when the high-pressure hydrogen tank 30 as the final product is obtained.

  From FIG. 6, the highest temperature is the resin layer part (layer number 2) inside the outermost layer part on the outer surface side of the fiber reinforced resin layer 20 indicated by layer number 1 in the figure, and then the highest. Is the outermost layer portion of layer number 1. Each resin layer part of layer numbers 3 to 5 has a temperature lower than that of the outermost layer part of layer number 1 in the order of increasing depth of the layer. And the temperature distribution of each resin layer site | part when the temperature of each layer became stable in a certain time, for example in FIG. 6, reflects the temperature condition for each said layer, and the outermost layer site | part (layer number of the fiber reinforced resin layer 20) A temperature difference ΔTm indicated by a white arrow in the figure is generated between 1) and the resin layer portion (layer number 2) inside thereof. Such a phenomenon can be explained as follows.

  The induction heating coil 220 in FIG. 5 performs high-frequency induction heating in the outermost layer portion (layer number 1) of the fiber reinforced resin layer 20, the inner resin layer portion (layer number 2), and the lower layer side resin layer portion (layer number). Although progress is made in each layer of 3 to 5), the state of induction heating in each layer is different as follows. Since the outermost layer portion (layer number 1) of the fiber reinforced resin layer 20 is closest to the induction heating coil 220 and is easily affected by the magnetic flux generated by the induction heating coil 220, the eddy current is large. High frequency induction heating is most advanced. Although the resin layer part (layer numbers 2 to 5) on the lower layer side from the outermost layer part (layer number 1) is subjected to induction heating by the induction heating coil 220, it is less likely to be affected by magnetic flux by separating from the coil. Therefore, the heating does not proceed as much as the outermost layer portion (layer number 1).

  In the resin layer part (layer number 2) inside the outermost layer part (layer number 1) of the fiber reinforced resin layer 20, in addition to the high-frequency induction heating in the layer part, the high-frequency induction heating by the induction heating coil 220 is most advanced. Receives heat propagation from the outer layer site (layer number 1). On the other hand, in the outermost layer portion (layer number 1), heat is released from the surface of the layer, so that the temperature of the inner resin layer portion (layer number 2) is higher than that of the outermost layer as seen in the graph of FIG. . In the resin layer part on the lower layer side (layer numbers 3 to 5) from the resin layer part of layer number 2, high-frequency induction heating in each resin layer part and heat propagation from the resin layer part on the upper layer side occur. Since it does not advance from the resin layer part of layer number 2, the temperature of each layer becomes lower than the resin layer part of layer number 2. Considering this, the thermosetting furnace 200 has its control device so that the temperature of the resin layer part (layer number 2) inside the outermost layer part (layer number 1) of the fiber reinforced resin layer 20 becomes the control upper limit temperature. 230 controls the high-frequency current to be supplied to the induction heating coil 220. The control upper limit temperature in this case is also the heating upper limit temperature when heating the thermosetting resin, and properties such as the melting temperature of the thermosetting resin for forming the source material resin of the liner 10 and the fiber reinforced resin layer 20. Further, the temperature is determined from the resistance temperature of the chemical adhered to the fiber surface of the resin-impregnated carbon fiber W, specifically, the chemical that improves the familiarity between the fiber and the resin. In particular, in the case of a thermosetting resin, when the temperature is close to the melting temperature due to its properties, the decrease in viscosity becomes significant, and this point is also taken into consideration in determining the control upper limit temperature.

  In the thermosetting furnace 200 of the present embodiment, as shown in FIG. 5, the temperature state of each layer portion shown in FIG. 6 is stored in the memory area of the control device 230, and the above-described high-frequency current is supplied with reference to this. To control. The temperature state thus stored is associated with each resin layer portion (layer numbers 1 to 5) in the layer thickness direction of the fiber reinforced resin layer 20, and is prepared for each high-pressure hydrogen tank 30 to be manufactured. For example, if the size of the high-pressure hydrogen tank 30 and the thermosetting resin constituting the fiber reinforced resin layer 20 are different, the temperature status of each layer portion in FIG. 6 is stored. FIG. 7 is a flowchart for explaining energization control of the high-frequency current to the induction heating coil 220.

  The energization control shown in FIG. 7 is started when the intermediate product tank 12 is set in the furnace of the thermosetting furnace 200 and the rotation around the axis becomes a constant speed, and the control device 230 applies a high-frequency current to the induction heating coil 220. A high-frequency current is supplied from the generation power supply 240, and this is continued (step S100). Next, the control device 230 inputs the outer surface temperature of the fiber reinforced resin layer 20 from the temperature sensor 242 (see FIG. 5) (step S110), and the input temperature, that is, the maximum temperature of the fiber reinforced resin layer 20 shown in FIG. With reference to the temperature of the outer layer part (layer number 1) and the temperature state of FIG. 6 stored in the memory, the temperature of the resin layer part (layer number 2) inside the outermost layer part (layer number 1) is calculated ( Step S120). The inner resin layer part (layer number 2) that is the target of such temperature calculation is the heat from the temperature state associated with each resin layer part (layer numbers 1 to 5) in the layer thickness direction of the fiber reinforced resin layer 20. It will be specified as the resin layer part which becomes the maximum temperature at the time of curing.

  In the temperature calculation in step S120, the input temperature of the outermost layer portion (layer number 1) from the temperature sensor 242 as described above can be used, and the process after the current energization to the induction heating coil 220 is started. It is also possible to estimate the temperature of the outermost layer portion (layer number 1) based on time and use this estimated temperature. Further, since the temperature difference ΔTm between the outermost layer portion (layer number 1) and the inner resin layer portion (layer number 2) shown in FIG. 6 can be obtained from the start of heating corresponding to the temperature rise situation of the outermost layer portion, It is also possible to calculate with reference to this temperature difference ΔTm. In addition, the temperature of the resin layer part (layer number 2) inside the outermost layer part (layer number 1) can be calculated without using the temperature of the outermost layer part (layer number 1). That is, since the temperature condition of FIG. 6 includes the temperature condition of the inner resin layer part (layer number 2), the temperature of the inner resin layer part (layer number 2) is calculated based on the elapsed time after the start of energization. May be.

  Next, the control device 230 determines whether or not the calculated temperature of the resin layer portion (layer number 2) has reached the control upper limit temperature described above (step S130), and the resin layer portion (layer number 2). The process is repeated from step S100 until the temperature reaches the control upper limit temperature. On the other hand, when the temperature of the resin layer portion (layer number 2) reaches the control upper limit temperature in step S130, the control device 230 stops energization of the high-frequency current to the induction heating coil 220 and the fiber reinforced resin layer 20. The cooling curing is aimed at (step S140). Thereby, the high pressure hydrogen tank 30 in which the fiber reinforced resin layer 20 is cured is obtained.

  As described above, in the present embodiment, when the high-pressure hydrogen tank 30 reinforced with the thermoset fiber reinforced resin layer 20 is manufactured, the fiber in the thermosetting resin of the fiber reinforced resin layer 20 is subjected to thermosetting. The temperature of the resin layer portion (layer number 2) inside the outermost layer portion (layer number 1: see FIG. 6) of the reinforced resin layer 20 is set to the control upper limit temperature when the high-frequency current is supplied to the induction heating coil 220. Set. For this reason, when high-frequency induction heating is performed by the induction heating coil 220, the resin layer part of layer number 2 where the temperature rises most can be heated (induction heating) so as not to exceed the control upper limit temperature. On the other hand, the induction heating coil 220 is energized with a high-frequency current so that the temperature of the outermost layer portion (layer number 1) closest to the induction heating coil 220 and where the high-frequency induction heating by the coil proceeds most is the control upper limit temperature. If the control upper limit temperature is set, the resin layer part (layer number 2) inside the outermost layer part (layer number 1) is heated to a temperature higher than the control upper limit temperature. If the resin layer part (layer number 2) becomes higher than the control upper limit temperature in this way, the viscosity of the thermosetting resin in the part and the seepage associated therewith become remarkable, resulting in high Vf. It might be. However, according to the thermosetting furnace 200 of the present embodiment, according to the method of manufacturing the high-pressure hydrogen tank 30 from the intermediate product tank 12 using the thermosetting furnace 200, the fiber reinforced resin layer 20 is formed. Since the temperature of the inner resin layer part (layer number 2), which is the maximum temperature when each resin layer part is heated by induction heating, is set as the control upper limit temperature, Vf corresponds to this upper limit temperature. It can be kept within the range, and variation in Vf can be suppressed. And since the dispersion | variation in Vf at the time of thermosetting of the fiber reinforced resin layer 20 is suppressed, in the obtained high-pressure hydrogen tank 30, it becomes a tank which has high tank intensity | strength and durability which can be practically used. .

  Moreover, in the tank manufacturing method of the present embodiment, each temperature increase state when each resin layer portion (layer numbers 1 to 5) of the fiber reinforced resin layer 20 is heated by induction heating by the induction heating coil 220 is previously set. The correspondence (see the graph of FIG. 6) is stored in association with each resin layer portion in advance. Then, referring to the temperature detected for the outermost layer portion (layer number 1) where the high-frequency induction heating is most advanced and the stored temperature rise state, the control upper limit temperature is set for the resin layer portion of the layer number 2 where the temperature rise is most advanced. Since heating (induction heating) is performed so as not to exceed, high-pressure hydrogen tank 30 in which variation in Vf is suppressed can be easily and reliably manufactured.

  Next, a modified example of the thermosetting furnace 200 will be described. FIG. 8 is an explanatory view showing a temperature distribution of each resin layer portion of the fiber reinforced resin layer 20 while showing a schematic configuration of a thermosetting furnace 200 of a modified example.

  The thermosetting furnace 200 of this modification has a cooling mechanism in addition to the induction heating coil 220 for induction heating the fiber reinforced resin layer 20. The cooling mechanism includes a configuration for cooling the outermost layer portion on the outer surface side of the fiber reinforced resin layer 20. For example, a cooling air blowing nozzle is disposed opposite to the outermost layer portion, or a circulation pipe for a coolant such as cooling water is provided on the outermost layer. It is configured by being arranged near the surface of the part. And this cooling mechanism cools the outermost layer site | part of the outer surface side of the fiber reinforced resin layer 20, and aims at the thermal radiation from the said layer site | part. In this case, since the fiber reinforced resin layer 20 is subjected to high frequency induction heating by the induction heating coil 220 as described above, in this modification, heat is radiated from the outermost layer portion on the outer surface side of the fiber reinforced resin layer 20. The fiber reinforced resin layer 20 is induction-heated by the induction heating coil 220 while aiming. And according to this modification, as shown in FIG. 8, since the variation in the temperature distribution in the thickness direction of the fiber reinforced resin layer 20 can be suppressed through the heat radiation from the outermost layer portion, the variation in Vf can be highly effective. Can be suppressed. In addition, since the dispersion of the curing shrinkage of the resin can be prevented by suppressing the variation in the temperature distribution during the thermosetting of the fiber reinforced resin layer 20, the occurrence of cracks based on the variation of the curing shrinkage can also be suppressed. Therefore, the obtained high-pressure hydrogen tank 30 has high tank strength and durability.

  Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and can be implemented in various modes without departing from the scope of the present invention. For example, in the above embodiment, the high-pressure gas tank is the high-pressure hydrogen tank 30, but the present invention is not limited to this. For example, a high-pressure gas tank that stores other high-pressure gas such as natural gas may be used.

  Further, in the above-described embodiment, when performing energization control including stopping energization to the induction heating coil 220 (step S140), the inner resin layer portion that reaches the maximum temperature through reference to the stored temperature state (FIG. 6) Although the temperature of (layer number 2) was calculated, it is not restricted to this. For example, the outer surface temperature of the fiber reinforced resin layer 20 obtained from the temperature sensor 242, that is, the temperature of the outermost layer portion (layer number 1) of the fiber reinforced resin layer 20 is set to the inner resin layer portion (layer number 2) that becomes the maximum temperature. ) Temperature can be substituted. This is because the temperature of the outermost layer portion (layer number 1) of the fiber reinforced resin layer 20 corresponds to the temperature of the inner resin layer portion (layer number 2) following the stored temperature state (FIG. 6). The temperature of the outermost layer part (layer number 1) of the fiber reinforced resin layer 20 is substituted for the temperature of the inner resin layer part (layer number 2) that becomes the maximum temperature, and this substitute temperature (outermost layer part (layer number 1) Based on the temperature), it is also possible to stop energization of the induction heating coil 220 in step S140. Specifically, the temperature of the outermost layer portion (layer number 1) of the fiber reinforced resin layer 20 obtained from the temperature sensor 242 is lower than the control upper limit temperature described above by a predetermined temperature difference (ΔTm in FIG. 6). Then, the energization stop to the induction heating coil 220 in step S140 is performed. Even in this case, the temperature of the inner resin layer portion (layer number 2) that becomes the maximum temperature can be prevented from exceeding the control upper limit temperature, and the above-described effects can be achieved.

DESCRIPTION OF SYMBOLS 10 ... Liner 10a ... Cylinder part 10b ... Dome part 12 ... Intermediate product tank 14 ... Base 20 ... Fiber reinforced resin layer 30 ... High pressure hydrogen tank 100 ... FW apparatus 110 ... Creel stand 112 ... Bobbin 114 ... Fixed pulley 120 ... Path part DESCRIPTION OF SYMBOLS 130 ... Winding part 132 ... Ikuchi guide 134 ... Rotation drive device 150 ... Control part 200 ... Thermosetting furnace 212 ... Tank axial support shaft 220 ... Induction heating coil 230 ... Control apparatus 240 ... High frequency current generation power supply 242 ... Temperature sensor W … Resin impregnated carbon fiber AX… tank center axis

Claims (7)

A method for manufacturing a high-pressure gas tank, comprising:
A step (a) of preparing a tank intermediate product having a fiber reinforced resin layer formed by winding a fiber impregnated with a thermosetting resin around the outer periphery of a hollow liner serving as a tank container;
(B) a step of inductively heating and thermally curing the fiber reinforced resin layer of the tank intermediate product using an induction heating coil for inducing high-frequency induction heating while rotating the tank intermediate product around the tank axis; With
In the step (b),
A method for manufacturing a high-pressure gas tank that controls the application of a high-frequency current to the induction heating coil on the premise of the presence of a temperature distribution in the resin layer portion in the layer thickness direction of the fiber reinforced resin layer that is heated by receiving the induction heating .   In the step (b), the temperature of the maximum temperature resin layer portion that is the maximum temperature among the resin layer portions in the layer thickness direction does not exceed the heating upper limit temperature determined by the conditions including the properties of the thermosetting resin. Thus, the manufacturing method of the high pressure gas tank of Claim 1 which controls electricity supply of the high frequency current to the said induction heating coil. It is a manufacturing method of the high-pressure gas tank according to claim 2,
In the step (b),
Based on a correspondence relationship in which the temperature rising state when the fiber reinforced resin layer is heated by receiving the induction heating is associated with each resin layer portion in the layer thickness direction, the maximum temperature resin layer portion is set to the fiber reinforced. A method for producing a high-pressure gas tank, wherein the outermost layer portion on the outer surface side of the resin layer is the inner resin layer portion.   In the step (b), when the fiber reinforced resin layer is heated by receiving the induction heating, the temperature of the inner resin layer portion is obtained using the correspondence relationship, and the obtained inner resin layer is obtained. The method for manufacturing a high-pressure gas tank according to claim 2 or 3, wherein energization of a high-frequency current to the induction heating coil is controlled in accordance with a temperature of the part.   In the step (b), when the fiber reinforced resin layer is heated by receiving the induction heating, the temperature of the other resin layer portion corresponding to the temperature of the inner resin layer portion and the corresponding relationship is set. 5. The method for producing a high-pressure gas tank according to claim 4, wherein the flow of the high-frequency current to the induction heating coil is controlled by substituting the obtained temperature of the other resin layer portion with the temperature of the inner resin layer portion. .   The said process (b) WHEREIN: The said fiber reinforced resin layer is induction-heated with the said induction heating coil, aiming at the thermal radiation from the outermost layer site | part of the outer surface side of the said fiber reinforced resin layer. A method for producing a high-pressure gas tank according to 1. An apparatus used for manufacturing a high-pressure gas tank having a fiber-reinforced resin layer that is thermoset by impregnating a thermosetting resin on the outer periphery of a hollow liner serving as a tank container,
A fiber winding means for winding the fiber impregnated with the thermosetting resin before thermosetting around the outer periphery of the liner to form the fiber reinforced resin layer, and obtaining a tank intermediate product;
Thermosetting in which the fiber reinforced resin layer of the rotating tank intermediate product is induction-heated and thermoset using an induction heating coil that induces high-frequency induction heating while rotating the tank intermediate product around the tank axis. Means and
The thermosetting means is
A storage unit that stores a correspondence relationship for each resin layer part in the layer thickness direction of the fiber reinforced resin layer, when the temperature of the fiber reinforced resin layer is increased by receiving the induction heating,
Based on the correspondence relationship, the maximum temperature resin layer part that becomes the maximum temperature among the resin layer parts when the fiber reinforced resin layer is heated, the temperature of the determined maximum temperature resin layer part is, An apparatus for manufacturing a high-pressure gas tank, comprising: a control unit that controls energization of a high-frequency current to the induction heating coil so as not to exceed a heating upper limit temperature determined by conditions including properties of the thermosetting resin.

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