JP2008286297A - High-pressure tank manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve space-saving and fatigue durability in a high-pressure tank. <P>SOLUTION: A liner is set (S10) and filament winding forming of one to ten layers is performed using prepreg where half-hardened thermosetting resin has been impregnated into fiber bundles (S12). Then, filament winding forming of 11 to 36 layers is performed using fiber bundles impregnated with a liquid thermosetting resin (S14). Then, the thermosetting resin is hardened by heating to manufacture the high-pressure tank (S16). In the prepreg, the thermosetting resin is highly viscous and is less transuded from the fiber bundle and therefore a fiber density inside layers can be prevented from lowering. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high-pressure tank manufactured by winding a fiber-reinforced composite material.

  A technique for manufacturing a high-pressure tank by winding a fiber-reinforced composite material over a plurality of layers on the outside of a liner is known.

  In the following Patent Document 1, resin is squeezed out from the inner layer due to the tightening tension in the process of manufacturing the high-pressure tank by winding the fiber-reinforced composite material, and thereby the fiber-reinforced composite material of the inner layer or the outer layer. Has been described as meandering. In order to solve this problem, there is also described a technique for managing the amount of resin squeezed out to a predetermined value by controlling the amount of resin contained in the fiber-reinforced composite material and the tension during winding.

  The following Patent Document 2 describes a technique relating to a plastic pipe used for a drive shaft for automobiles, a roll for film conveyance / printing, and the like. In this technique, a prepreg sheet using a thermosetting resin as a matrix is wound around a mandrel, and a thermoplastic resin tape is wound around the outer layer, followed by thermosetting and thermocompression bonding under the curing conditions of the thermosetting resin. Thus, a resin having a certain thickness is provided on the pipe surface.

  Patent Document 3 below discloses a technique for manufacturing a pipe that is used in golf shafts, fishing rods, and the like and has high torsional fracture strength, bending strength, impact strength, and the like by laminating a fiber reinforced resin layer. Specifically, a prepreg tape member or the like is wound around the outer periphery of the carbon fiber reinforced prepreg wound around the mandrel at a predetermined tension, and further, the carbon fiber reinforced prepreg is wound around the outer periphery. A technique for heat curing is disclosed.

JP 2004-66637 A Japanese Unexamined Patent Publication No. 7-80973 Japanese Patent Laid-Open No. 5-185541

  As described in Patent Document 1, in the fiber reinforced composite material, the resin filled between the fiber bundles oozes due to the effect of tightening by the fiber reinforced composite material wound around the outside. In the inner layer (liner side layer), the fiber density (or fiber volume content Vf) tends to increase (resin decreases). In particular, when the working pressure of the high-pressure tank is increased, it is necessary to increase the fiber reinforced composite material layer in order to ensure strength, and the Vf increase in the inner layer becomes significant.

  In general, it is known that in a fiber reinforced composite material layer having a high Vf, fatigue durability performance is lowered, for example, cracks are likely to occur. In particular, when a high-pressure tank is filled with a high-pressure gas or liquid, the fiber-reinforced composite layer on the inner layer side tends to have a greater stress, and in order to increase the fatigue durability of the high-pressure tank and extend its life It is desirable to make Vf in the inner layer relatively low.

  However, if Vf is simply lowered in the entire high-pressure tank, the outer diameter increases as the resin increases. Moreover, in the technique of the said patent document 1, there are many restrictions, such as selection of a fiber reinforced composite material and tension setting at the time of winding, and a desired high-pressure tank cannot necessarily be obtained. Also, in the pipe manufacturing techniques of Patent Documents 2 and 3, there is no description focusing on the difference in resin characteristics between the inner layer and the outer layer.

  An object of the present invention is to save space and improve fatigue durability in a high-pressure tank.

  Another object of the present invention is to provide a high-pressure tank with improved in-vehicle convenience.

  In one aspect of the method for producing a high-pressure tank according to the present invention, a first fiber bundle including a first fiber bundle composed of a plurality of fibers and a thermosetting resin provided in an uncured state between the fibers on the outer periphery of the hollow liner. A step of winding a fiber reinforced composite material to form a first fiber reinforced composite material layer, and a non-hardening between each fiber and a second fiber bundle composed of a plurality of fibers on the outer periphery of the first fiber reinforced composite material layer A step of winding a second fiber reinforced composite material including a thermosetting resin provided in a state to form a second fiber reinforced composite material layer, and the first fiber reinforced composite material layer and the second fiber reinforced material. A step of curing the thermosetting resin by heating after the composite material layer is formed, and at the time of winding, the viscosity of the thermosetting resin provided in the first fiber-reinforced composite material is The thermosetting resin provided in the second fiber reinforced composite material It is set higher than the viscosity.

  The high-pressure tank is a container that can hold gas (gas) or liquid at high pressure, and is also called a pressure-resistant tank or a pressure container. The liner is a container used as an inner cylinder of a high-pressure tank, and is typically made of a resin or metal having a high holding power for gas or liquid filled therein. A fiber reinforced composite material is a material that includes a fiber bundle in which a plurality of fibers are bundled and a thermosetting resin as a matrix provided between these fibers, and is wound around the outer periphery of the liner to provide strength of the high-pressure tank. To increase. The fiber bundle may be one in which a plurality of fibers are simply gathered together, or may be one in which a plurality of fibers are woven. Moreover, the fiber which comprises a fiber bundle may be continuous (it is not interrupted from the one end wound) to the other end, and may be discontinuous. Examples of the fiber include carbon fiber, glass fiber, and aramid fiber. Moreover, as an example of the thermosetting resin provided between fibers, an epoxy resin, a polyurethane resin, a diallyl phthalate resin, a phenol resin, a polyester resin, etc. can be mentioned. An imparting agent (for example, a curing agent or a flexibility imparting agent) for controlling the curing temperature or the like may be added to the resin.

  The thermosetting resin contained in the first fiber reinforced composite material and the thermosetting resin contained in the second fiber reinforced composite material are in an uncured state when wound. The uncured state refers to a state in which plastic deformation is possible. At least at the time of winding, the thermosetting resin contained in the first fiber reinforced composite material is set to have higher viscosity than the thermosetting resin contained in the second fiber reinforced composite material. The level of viscosity is typically evaluated by the magnitude of the viscosity coefficient. The viscosity can be controlled, for example, by changing the composition of the resin or changing the degree of progress of thermosetting. The viscosity does not need to be uniform in the first fiber reinforced composite material or in the second fiber reinforced composite material, but the resin having the lowest viscosity in the first fiber reinforced composite material is the second fiber. The reinforced composite material is set to have a higher viscosity than the most viscous resin.

  The first fiber reinforced composite material is wound around the outer periphery of the liner to form a first fiber reinforced composite material layer. The first fiber reinforced composite material layer is formed so as to cover the entire outer periphery of the liner (exclusive portions such as openings and handle portions are not limited to this). This first fiber-reinforced composite material layer is typically formed by winding the first fiber-reinforced composite material a plurality of times in the thickness direction (direction away from the liner). Similarly, the second fiber reinforced composite material is wound around the outer periphery of the first fiber reinforced composite material layer to form a second fiber reinforced composite material layer. The second fiber reinforced composite material layer is basically formed so as to entirely cover the outer periphery of the first fiber reinforced composite material layer, and is formed by winding a plurality of times in the thickness direction.

  The first fiber reinforced composite material layer is provided in contact with the liner or in contact with another member provided on the outer surface of the liner. In other words, the first fiber reinforced composite material layer is provided so as to be located on the innermost side as the fiber reinforced composite material layer. The second fiber reinforced composite material layer is provided outside the first fiber reinforced composite material layer. Typically, the second fiber reinforced composite material layer is provided in contact with the first fiber reinforced composite material layer, but another member may be sandwiched between the first fiber reinforced composite material layer. . The first fiber reinforced composite material and the second fiber reinforced composite material may be discontinuous materials (that is, materials in which resin and fiber are not physically connected), but are continuous materials (resin or fiber materials). It may be a material in which at least one of them is physically connected) and continuously wound.

  In the vicinity of the inner layer where the first fiber-reinforced composite material layer is formed, the amount of resin leaching tends to increase by tightening compared to the outer layer, and when the gas or liquid is filled in the high-pressure tank Large stresses tend to act. Therefore, the viscosity of the first fiber-reinforced composite material wound around this is set higher than the viscosity of the second fiber-reinforced composite material at least during winding. Thereby, since the amount of the resin leaking from the wound first fiber reinforced composite material layer can be relatively reduced, the viscosity of the first fiber reinforced composite material and the second fiber reinforced composite material before winding is reduced. Compared with the case where it makes it the same, the degree to which the fiber density of a 1st fiber reinforced composite material layer becomes higher than the fiber density of a 2nd fiber reinforced composite material layer at least is suppressed.

  The fiber of the first fiber reinforced composite material layer is adjusted by adjusting the fiber density in the first fiber reinforced composite material and the viscosity of the resin in the second fiber reinforced composite material, or adjusting the tension at the time of winding. The fiber density of the second fiber reinforced composite material layer may be set to the same level, or the fiber density of the first fiber reinforced composite material layer may be set lower than the fiber density of the second fiber reinforced composite material layer. Also good. The fiber density of the first fiber reinforced composite material layer and the fiber density of the second fiber reinforced composite material layer are determined experimentally after considering the strength, fatigue durability, size, etc. of the high-pressure tank. Or it can be decided based on a theoretical basis. In any case, according to this configuration, the fiber-reinforced composite material layer can be made relatively thin to save space, and the fatigue durability of the fiber-reinforced composite material layer can be increased. This space saving is particularly effective in a situation where a space that can be used is limited, such as a mobile object (for example, a vehicle, a ship, or an aircraft).

  In one aspect of the high-pressure tank manufacturing method of the present invention, at the time of winding, the thermosetting resin provided in the first fiber reinforced composite material is the thermosetting resin provided in the second fiber reinforced composite material. It is in a semi-cured state where the curing has proceeded compared to the resin, whereby the viscosity of the thermosetting resin provided in the first fiber reinforced composite material is the thermosetting property provided in the second fiber reinforced composite material. It is set higher than the viscosity of the resin. Here, the semi-cured state in which the curing of the thermosetting resin has progressed refers to a state in which the bonding of the resin molecules has progressed due to resin polymerization or the like, and the fluidity has relatively decreased, and is called a prepreg There is also. In the semi-cured state, generally, the viscosity becomes high, so that even when a high pressure is applied, the amount of leaching from the fiber-reinforced composite material layer is reduced.

  In one aspect of the high-pressure tank manufacturing method of the present invention, the thermosetting resin provided in the second fiber reinforced composite material has the same composition as the thermosetting resin provided in the first fiber reinforced composite material. The resin kept in a liquid state at the time of winding so that the viscosity of the thermosetting resin provided in the first fiber reinforced composite material is the thermosetting resin provided in the second fiber reinforced composite material. It is set higher than the viscosity of. Here, the liquid state means, for example, a state in which fluidity is ensured to be a drop or drop. By using resins having the same composition and different curing degrees, an effect of smoothly bonding the first fiber-reinforced composite layer and the second fiber-reinforced composite layer in the curing stage can be expected.

  Hereinafter, embodiments of the present invention will be exemplified.

  FIG. 1 is a schematic cross-sectional view of a high-pressure tank 10 according to the present embodiment. In the high-pressure tank 10, a CFRP layer 14 in which carbon fiber reinforced plastic (CFRP) as a fiber reinforced composite material is wound is formed on the outer periphery of a resin-made liner 12 made into a cylindrical shape. A glass layer 16 as a protective layer is formed on the outer periphery of 14. Metal caps 18 and 20 are attached to both ends of the liner 12.

  The high-pressure tank 10 is a container that stores fuel gas such as hydrogen or natural gas at high pressure. The high-pressure tank 10 may be used as a stationary type or mounted on a moving body. For example, when mounted on a fuel cell vehicle and used, typically, a high-pressure tank 10 having a total length of 800 to 1500 mm and a diameter of about 200 to 500 mm is prepared. Filled with pressure fuel gas.

  FIG. 2 is a view showing a cross-sectional structure of the side surface of the high-pressure tank 10 indicated by reference numeral 22 in FIG. In the high-pressure tank 10, a liner 12 is provided on the innermost side, a CFRP layer 14 is provided on the outer side, and a glass layer 16 is provided on the outer side. The CFRP layer 14 is formed by winding a bundle of CFRP containing a plurality (for example, several thousand to several tens of thousands) of carbon fibers to form a multilayer (for example, about 10 to several tens of layers). Of the CFRP layer 14, the inner layer 24 is manufactured by winding CFRP containing a semi-cured resin called a prepreg, and the outer layer 26 is manufactured by winding CFRP containing a liquid resin. ing.

  Then, the manufacturing method of the high-pressure tank 10 is demonstrated using FIG. FIG. 3 is a flowchart showing a manufacturing procedure of the high-pressure tank 10, and here, description will be made assuming that 36 CFRP layers 14 are formed. FIG. 4 is a schematic view showing a process of forming the CFRP layer 14.

  In the manufacturing process, first, the liner 12 to which the base is attached is set on the rotary shaft 30 (S10). And, for the inner layer (for example, 1 to 10 layers), about 20,000 carbon fibers having a diameter of 7 μm are bundled, and a fiber bundle 32 in which a semi-cured resin is provided between the carbon fibers. Using the (prepreg), the CFRP layer 14 is subjected to filament winding molding (hereinafter sometimes referred to as FW molding) (S12). Here, filament winding molding refers to a molding method in which a fiber bundle impregnated with resin is wound. When the width of the fiber bundle is relatively wide, it may be called tape winding molding. For example, the fiber bundle is set to several mm in the width direction and about 0.01 mm to several mm in the thickness direction.

  For example, the prepreg impregnates the fiber bundle 32 sent from the bobbin in an impregnation bath in which liquid epoxy resin is stored, and then polymerizes the resin to a semi-cured state by gentle heating. Can be manufactured. Moreover, it is also possible to manufacture a prepreg separately from the manufacturing of the high-pressure tank. For example, a prepreg generally distributed may be used.

  The winding method is not particularly limited. For example, hoop winding (as shown in FIG. 4, the fiber bundle 32 is set almost perpendicularly to the rotating shaft 30 and the winding position is gradually shifted. Winding method) or helical winding (winding method in which the fiber bundle 32 is set obliquely with respect to the rotation shaft 30 and the winding location is largely shifted), or a plurality of fiber bundles Winding may be performed after braiding the braid.

  A fiber bundle 32 impregnated with a liquid resin is FW-molded on the outer layers (11 to 36 layers) on which the prepreg is FW-molded (S14). This method is sometimes called a WET method, differently from a method using a prepreg. Specifically, the fiber bundle 32 is wound around the high-pressure tank 10 without being subjected to a semi-curing treatment after being immersed in a liquid impregnation bath and impregnated with an epoxy resin. The components, number and size of the fiber bundle 32 used in the WET method, the component of the resin to be impregnated, the temperature, and the like can be the same as or different from those in the prepreg method.

  When the FW molding is completed up to 36 layers, the high pressure tank 10 is heated to cure the epoxy resin of the CFRP layer 14 (S16). Then, the process which forms the glass layer as a protective layer is performed with respect to the surface of the high pressure tank 10 (S18).

  FIG. 5 is a diagram schematically illustrating the fiber volume content Vf in the CFRP layer 14 of the high-pressure tank 10 manufactured as described above. In FIG. 5, the horizontal axis represents Vf, and the vertical axis represents the layer of the CFRP layer 14. 5A shows a case where FW molding is performed on all layers by reference for reference, and FIG. 5B uses prepreg for 1 to 10 layers, and 11 to 36 layers. The case where the WET method is adopted is shown.

  In the example of FIG. 5A, the value of Vf increases in the inner layer. This is because the value of Vf is constant in the fiber bundle before winding, but in the inner layer that receives a lot of tension accompanying winding, the resin oozes and the resin impregnation amount decreases (fiber ratio). This is to increase. Similarly, in the example of FIG. 5B, among the 1 to 10 layers and the 11 to 36 layers, the inner layer has a higher Vf. However, in the example of FIG. 5 (b), Vf in the 11th to 36th layers shows a distribution in which the value increases sharply in the inner layer as in the case of FIG. 5 (a). Although the value is slightly larger, it shows a distribution that can be considered constant compared to the outer layer. This is because in the prepreg, the fluidity of the resin is relatively small and the amount of the resin leaching is reduced. In addition, the leaching amount of the resin does not change so much depending on the magnitude of the FW molding tension with respect to the outer layer. That is, when the prepreg is used, the CFRP layer 14 having a value close to the fiber volume content Vf in the prepreg before winding can be formed regardless of the tension setting at the time of winding. For example, in the example shown in FIG. 5B, the resin amount of the prepreg is set so that 1 to 10 layers of Vf is approximately the same as or slightly smaller than 11 layers of Vf.

  In the above description, an example in which 1 to 10 layers are FW-molded with a prepreg and 11 to 36 layers are FW-molded with WET has been described. However, how many layers the FW molding by the prepreg is set can be variously set. As an example, an embodiment in which the FW molding is performed by 1 to 4 layers by prepreg and 5 to 36 layers by WET can be mentioned. It is also possible to perform winding with the degree of curing of the resin set in a plurality of stages. As an example, a fiber bundle containing a resin that is relatively hardened most is used for the first to fourth layers, and a fiber bundle containing a resin that is moderately cured is used for the fifth to tenth layers. The ~ 36th layer can include an embodiment in which a fiber bundle containing a resin that has not been cured most (for example, a resin that has not been cured at all) is used. Furthermore, it is possible to continuously change from WET to prepreg. For example, by gradually relaxing the degree of heating of the fiber bundle impregnated with the liquid resin, FW molding that continuously changes from prepreg to WET can be performed. The specific setting is, for example, theoretically or experimentally under the condition that the fatigue durability performance required in the inner layer is satisfied and the CFRP layer 14 that provides the required strength is within a predetermined thickness. Can be determined.

It is sectional drawing of the high pressure tank concerning this Embodiment. It is a figure which shows the cross-section of the side surface of the high pressure tank of FIG. It is the flowchart which illustrated the manufacturing procedure of the high pressure tank. It is a schematic diagram explaining the manufacturing process of a high pressure tank. It is a schematic diagram which illustrates the fiber volume content rate in the CFRP layer of a high pressure tank.

Explanation of symbols

  10 high pressure tank, 12 liner, 14 CFRP layer, 16 glass layer, 18, 20 base, 24 inner layer, 26 outer layer, 30 rotating shaft, 32 fiber bundle.

Claims (3)

A first fiber reinforced composite material comprising a first fiber bundle composed of a plurality of fibers and a thermosetting resin provided in an uncured state between the fibers is wound around the outer periphery of the hollow liner. Laminating a material layer; and
A second fiber reinforced composite material comprising a second fiber bundle composed of a plurality of fibers and a thermosetting resin provided in an uncured state between the fibers is wound around the outer periphery of the first fiber reinforced composite material layer, Laminating and forming a second fiber reinforced composite layer;
Curing the thermosetting resin by heating after the first fiber reinforced composite material layer and the second fiber reinforced composite material layer are laminated and formed;
Including
At the time of winding, the viscosity of the thermosetting resin provided in the first fiber reinforced composite material is set higher than the viscosity of the thermosetting resin provided in the second fiber reinforced composite material. A high-pressure tank manufacturing method characterized by the above. In the high pressure tank manufacturing method according to claim 1,
At the time of winding, the thermosetting resin provided in the first fiber reinforced composite material is in a semi-cured state in which the curing has progressed compared to the thermosetting resin provided in the second fiber reinforced composite material. Thus, the viscosity of the thermosetting resin provided in the first fiber reinforced composite material is set higher than the viscosity of the thermosetting resin provided in the second fiber reinforced composite material. A high-pressure tank manufacturing method characterized. In the high pressure tank manufacturing method according to claim 2,
The thermosetting resin provided in the second fiber reinforced composite material has the same composition as the thermosetting resin provided in the first fiber reinforced composite material, and is a resin that is kept in a liquid state when wound. Thereby, the viscosity of the thermosetting resin provided in the first fiber reinforced composite material is set higher than the viscosity of the thermosetting resin provided in the second fiber reinforced composite material. A high-pressure tank manufacturing method.

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