Patent Grant
12036753
The present application claims priority from Japanese patent application JP 2021-137789 filed on Aug. 26, 2021, the entire content of which is hereby incorporated by reference into this application.
The present disclosure relates to a method for manufacturing a fiber-reinforced tank and a manufacturing device thereof.
JP 2020-085199 A discloses a method of manufacturing a fiber reinforced plastic (FRP) tank (hereinafter also referred to as a high-pressure tank). This manufacturing method first performs a coating step by wrapping fibers around a liner, then performs an impregnating step by impregnating the fibers with resin, and thereafter allows the resin to cure by heating the resin impregnated fibers.
JP 2019-056415 A discloses a method for manufacturing a high-pressure tank using such a resin transfer molding (RTM) method. This manufacturing method places a preform, in which a fiber layer is formed on an outer surface of a liner that forms an internal space of a high-pressure tank, in a mold, and rotates the preform in a circumferential direction in the mold about the central axis of the preform as a rotation center while injecting resin from a gate toward the preform placed in the mold.
The above manufacturing method using the RTM method performs the fiber wrapping step and the resin impregnating step separately when manufacturing a high-pressure tank. However, due to a large amount of fibers wrapped around the high-pressure tank and a large thickness of the fiber layer (laminae) formed by wrapping fibers, it may take a long time for the deep portion (innermost layer) of the fiber layer to be completely impregnated with resin.
In view of the foregoing, the present disclosure provides a method for manufacturing a tank and a manufacturing device thereof that can achieve resin impregnation within a short time.
In view of the foregoing, according to one aspect of the present disclosure, there is disclosed a method for manufacturing a tank, the tank including: a hollow liner including a cylindrical straight body portion and a dome portion that narrows gradually in a direction opposite to the straight body portion from an end portion of the straight body portion in an axial direction; and a reinforcing layer formed on an outer surface of the liner by impregnating with resin a fiber layer including fibers wrapped in an overlapping manner in a radial direction, the method including: wrapping the fibers in an overlapping manner in a radial direction around the outer surface of the liner such that a first fiber layer on an outer surface of the dome portion is less dense than a second fiber layer on an outer surface of the straight body portion and such that a portion of a lamina of the first fiber layer, which is less dense, is interposed continuously from the first fiber layer partially between laminae of the second fiber layer; and impregnating the fiber layer including the first fiber layer and the second fiber layer with the resin.
In some embodiments, impregnation of the fiber layer with the resin is performed separately in an axial direction and a radial direction of the liner.
In some embodiments, the resin is poured into the first fiber layer in the axial direction of the liner to impregnate the fiber layer with the resin; and the resin is poured into the second fiber layer in the radial direction of the liner to impregnate the fiber layer with the resin.
In some embodiments, after impregnation of the fiber layer with the resin is performed in the axial direction of the liner, impregnation of the fiber layer with the resin is performed in both of the axial direction and the radial direction of the liner.
In some embodiments, after the resin is poured into the first fiber layer in the axial direction of the liner, the resin is poured into the second fiber layer in the radial direction of the liner while pouring the resin into the first fiber layer in the axial direction of the liner to impregnate the fiber layer with the resin.
In some embodiments, the method includes wrapping fibers in an alternately woven manner around the outer surface of the dome portion to form the first fiber layer; wrapping fibers into a helical form or a hoop form around the outer surface of the straight body portion continuously from the first fiber layer to form the second fiber layer; and interposing a portion of a lamina of the first fiber layer, which is less dense, partially between laminae of the second fiber layer by wrapping fibers in an alternately woven manner continuously from the first fiber layer.
According to another aspect of the present disclosure, there is disclosed a manufacturing device of a tank, the tank including: a hollow liner including a cylindrical straight body portion and a dome portion that narrows gradually in a direction opposite to the straight body portion from an end portion of the straight body portion in an axial direction; and a reinforcing layer formed on an outer surface of the liner by impregnating with resin a fiber layer including fibers wrapped in an overlapping manner in a radial direction, the manufacturing device including: a mold configured to house a preform including the fibers wrapped in an overlapping manner in a radial direction around the outer surface of the liner such that a first fiber layer on an outer surface of the dome portion is less dense than a second fiber layer on an outer surface of the straight body portion and such that a portion of a lamina of the first fiber layer, which is less dense, is interposed continuously from the first fiber layer partially between laminae of the second fiber layer, and to allow impregnation of the fiber layer including the first fiber layer and the second fiber layer with the resin, in which the mold is provided with a plurality of runners defining gates through which the resin flows and that are open in the mold such that impregnation of the fiber layer with the resin is performed separately in an axial direction and a radial direction of the liner, and at least one of the plurality of runners is provided with an opening/closing mechanism.
In some embodiments, the plurality of runners includes a first runner through which the resin is poured into the first fiber layer in the axial direction of the liner and a second runner through which the resin is poured into the second fiber layer in the radial direction of the liner.
In some embodiments, the opening/closing mechanism is configured to open and close at least one of the plurality of runners such that after impregnation of the fiber layer with the resin is performed in the axial direction of the liner, impregnation of the fiber layer with the resin is performed in both of the axial direction and the radial direction of the liner.
In some embodiments, the plurality of runners includes a first runner through which the resin is poured into the first fiber layer in the axial direction of the liner and a second runner through which the resin is poured into the second fiber layer in the radial direction of the liner, the opening/closing mechanism is provided at least in the second runner, and after the resin is poured into the first fiber layer in the axial direction of the liner via the first runner in a state where the second runner is closed by the opening/closing mechanism, in a state where the second runner is opened by the opening/closing mechanism, the resin is poured into the second fiber layer in the radial direction of the liner via the second runner while pouring the resin into the first fiber layer in the axial direction of the liner via the first runner.
According to one aspect of the present disclosure, providing a portion with less dense fibers (low fiber density) in both of the dome portion and the straight body portion during fiber wrapping can reduce resistance in resin pouring. This can facilitate resin impregnation, thereby achieving completion of the resin impregnation within a short time.
In addition, since the resin pouring pressures in different directions (an axial direction and a lamina extending direction, a radial direction and a thickness direction) will not be interfered with each other during resin pouring, it is possible to achieve completion of the resin impregnation in the inner part within a short time.
Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.
The following describes an example of a high-pressure tank for fuel cell vehicles that is one example of a tank. The tank, to which the present disclosure is applied, is not limited to the high-pressure tank for fuel cell vehicles. The shape, the material, and the like of the liner and the preform that form the tank are also not limited to the illustrated example.
The RTM method wraps (winds) carbon fibers around a liner multiple times (in multiple layers) to form a preform with a fiber layer on the outer surface of the liner, impregnates the fiber layer of the preform with epoxy resin, and cures the epoxy resin, so as to manufacture a high-pressure tank for fuel cell vehicles including a fiber-reinforced resin layer including the carbon fibers and the epoxy resin on the outer periphery of the liner. The liner is a hollow container made of resin (for example, nylon resin) that defines the internal space of the high-pressure tank.
In such a high-pressure tank for fuel cell vehicles, the carbon fibers are laminated thickly, and so the resin hardly enters into the inner layer of the carbon fibers. When resin is poured at high pressure into the inner layer of the carbon fibers for impregnation, the quality and performance of the tank will deteriorate, such as deformation of the tank. In addition, as the tank has a cylindrical shape, it is hard to uniformly charge resin into the entire tank, making the resin impregnation ununiform. Moreover, pressure tends to concentrate on the vicinity of a gate, so its gate portion is under high pressure, and there is a large pressure difference between the gate portion and a resin flow end portion (i.e., a portion opposite to the gate portion).
That is, the high-pressure tank for fuel cell vehicles has the carbon fibers that are laminated very thickly (about 10 times that of a typical RTM molded body component) to keep enough strength, which makes it difficult to impregnate the fibers with resin. Simple tank rotation as in JP 2019-056415 A does not exert a good effect of resin impregnation into the inner layer of the carbon fibers. In addition, pouring resin at high pressure into the inner layer of the carbon fibers for impregnation may result in ununiform pressure distribution, and in some portion that is partially under high pressure, the quality and performance of the tank will deteriorate, such as deformation of the resin liner inside of the tank. In addition, since resin is less likely to flow to the portion opposite to the gate portion through a narrow gap between the mold and the tank, it is required to rotate the tank within the mold at high speed as disclosed in JP 2019-056415 A in order to flow the resin to the entire part of the tank before it cures. However, such high-speed rotation may cause damage to the carbon fibers due to a small space within the mold.
Then, the present embodiment employs the following configuration.
(Configuration of High-Pressure Tank)
First, a structure of a high-pressure tank 10 according to an embodiment of the present disclosure will be described in detail based on the drawings.
As shown in
The dome portion 12B includes, in its axial central part, a cylindrical portion 12C that protrudes (outwardly) toward the end portion of the liner 12 in the axial direction along the central axis CL. The cylindrical portion 12C has a substantially constant inside diameter and outside diameter that are smaller than those of the straight body portion 12A.
The high-pressure tank 10 is formed by wrapping in a layer form tape-like fibers (also referred to as fiber bundles) 16 with a predetermined width around the outer peripheral surface of the straight body portion 12A of the liner 12 and the outer peripheral surface of the dome portion 12B of the liner 12. The fiber 16 is made of fiber reinforced plastics (FRP) including glass fiber, carbon fiber, or aramid fiber, for example, and forms a fiber-reinforced-plastic layer (FRP layer) as a reinforcing layer on the outer peripheral surface (outer surface) of the liner 12.
Specifically, the fibers 16 are wrapped in an alternately woven manner around the outer peripheral surface (outer surface) of the dome portion 12B (hereinafter this may be referred to as “braided winding”), and the fibers 16 wound in a braided manner form a braiding layer 17B as a first fiber layer. Then, the braiding layer (first fiber layer) 17B is impregnated with a thermosetting resin 18 (
Meanwhile, the fibers 16 are helically wrapped around the outer peripheral surface (outer surface) of the straight body portion 12A (hereinafter this may be referred to as “helical winding”), and the helically wound fibers 16 form a helical layer 17A as a second fiber layer. Then, the helical layer (second fiber layer) 17A is impregnated with a thermosetting resin 18 (
The helical winding means that the fibers 16 are first wrapped around the entire outer peripheral surface of the straight body portion 12A at a predetermined winding angle +θ with respect to the central axis CL of the liner 12, and further wrapped around on top thereof (in a crossing direction on top of the fibers 16 wrapped at the winding angle +θ) at a predetermined winding angle −θ with respect to the central axis CL of the liner 12. That is, the helical layer (second fiber layer) 17A is configured such that the fibers 16 are wrapped into at least two layers around the outer peripheral surface of the straight body portion 12A at a predetermined winding angle +θ and a predetermined winding angle −θ. It should be noted that in practice, the fibers (bundles) 16 are wrapped (in an overlapping or laminating manner in the radial direction) into about several to several tens of layers, for example, though it depends on the internal pressure of the straight body portion 12A and the number of fibers (bundles) 16, and the like.
As described above, the braided winding means wrapping the fibers 16 in an alternately woven manner, and herein the braided winding means wrapping the fibers 16 around the entire outer peripheral surface of the dome portion 12B at a predetermined winding angle +θ and a predetermined winding angle −θ with respect to the central axis CL of the liner 12.
That is, herein, the fibers 16 are wrapped at the same winding angle θ in both of the braided winding and the helical winding. The winding angle θ may be within the range of θ=54.7°±10° including tolerances, specifically the range of θ=54.7°±5°, more specifically the range of θ=54.7°±1°.
This winding angle θ is an angle derived from stresses (axial stress and circumferential stress) on the straight body portion 12A when a predetermined internal pressure is acting, or, an angle resulting from the fact that the circumferential stress is twice as large as the axial stress. That is, though a detailed calculation process is omitted herein, calculating a winding angle θ according to stresses based on the netting theory can obtain tan2 θ=2, from which θ=54.7° (equilibrium angle) is derived.
Herein, the dome portion 12B undergoes a smaller stress as compared to the straight body portion 12A when an internal pressure is acting, and thus requires a lower level of reinforcement as compared to the straight body portion 12A. Consequently, as a basic structure, the braided winding (braiding layer 17B) with large fiber intervals, less dense fibers (low density), and a low strength as compared to the helical winding (helical layer 17A) is applied to the dome portion 12B, and the helical winding (helical layer 17A) with small fiber intervals, dense fibers (high density), and a high strength as compared to the braided winding (braiding layer 17B) is applied to the straight body portion 12A.
It should be noted that though description of a detailed structure is omitted herein, switching from the braided winding (braiding layer 17B) in the dome portion 12B to the helical winding (helical layer 17A) in the straight body portion 12A and inversely, switching from the helical winding (helical layer 17A) in the straight body portion 12A to the braided winding (braiding layer 17B) in the dome portion 12B, are performed within an area of a predetermined length in the axial direction near the boundary portion between the straight body portion 12A and the dome portion 12B as viewed in a direction crossing the axial direction along the central axis CL of the liner 12.
In addition, though not shown, in one example, one of the cylindrical portions 12C has a sealing plug fitted therein, and the other of the cylindrical portions 12C has a mouthpiece plug fitted therein, and a valve is mounted on the mouthpiece plug.
As shown in
It should be noted that in the braided winding of the fibers 16 around the one and the other of the dome portions 12B, as shown in
Meanwhile, in the helical winding of the fibers 16 around the straight body portion 12A, as shown in
In addition to the above-described basic structure of the dome portion 12B by the braided winding (braiding layer 17B) with large fiber intervals, less dense fibers (low density), and a low strength and the straight body portion 12A by the helical winding (helical layer 17A) with small fiber intervals, dense fibers (high density), and a high strength, the present embodiment employs the following configuration to facilitate impregnation of a resin 18 to achieve completion of the impregnation of the resin 18 within a short time.
That is, as shown in
Specifically, at a predetermined position of the lamina of the braiding layer 17B on the outer peripheral surface (outer surface) of the dome portion 12B, after the fibers 16 are wrapped in an alternately woven manner (i.e., after braided winding), continuously therefrom (i.e., without switching from braided winding to helical winding), the fibers 16 are wrapped in an alternately woven manner around on top of the helical layer 17A (helical layer 17A adjacent to the braiding layer 17B) (in the case of the innermost layer, the outer peripheral surface of the straight body portion 12A) on the outer peripheral surface (outer surface) of the straight body portion 12A (the 17D portion in
Through the above-described wrapping of the fibers 16 at one position (in one layer) or multiple positions (in multiple layers) between the laminae (including inside of the innermost layer and outside of the outermost layer) of the helical layer 17A (consisting of about several to several tens of layers, for example), the portion (17D) of the lamina of the braiding layer 17B is interposed continuously from the braiding layer 17B between the laminae of the helical layer 17A. It should be noted that between the laminae of the helical layer 17A, one lamina of the braiding layer 17B may be interposed or multiple laminae of the braiding layer 17B may be collectively interposed.
In this way, a portion of the lamina of the braiding layer 17B with large fiber intervals and less dense fibers (low density) is interposed (continuously from the braiding layer 17B) between the laminae of the helical layer 17A with small fiber intervals and dense fibers (high density). This facilitates impregnation of the resin 18 (in particular, in the helical layer 17A on the outer peripheral surface of the straight body portion 12A) during resin pouring, which will be described later, thus allowing completion of the impregnation of the resin 18 within a short time.
As described above, to form the high-pressure tank 10, a fiber layer 17 including the braiding layer 17B and the helical layer 17A (including the portion 17D of the lamina of the braiding layer 17B between the laminae of the helical layer 17A), formed by wrapping the fibers 16 in a layer form around the liner 12, is impregnated with an uncured thermosetting resin (for example, a mixture of an epoxy resin and a hardener; this may be simply referred to as “resin” in this specification) 18 having flowability, and then heated to allow the thermosetting resin to cure.
(Method for Manufacturing High-Pressure Tank)
A method for manufacturing the high-pressure tank 10 having the above-described configuration will be described in detail based on the drawings.
(Fiber Winding Step)
The high-pressure tank 10 according to the present embodiment is formed by firstly wrapping the fibers 16 around the outer peripheral surface of the liner 12. That is, as shown in
After the end of the braided winding of the fibers 16 around the outer peripheral surface of one of the dome portions 12B, the fibers 16 are then helically wound around the outer peripheral surface of the straight body portion 12A to form the helical layer 17A (second step). Specifically, the fibers 16 are helically wound successively around the straight body portion 12A from the end portion close to the one of the dome portions 12B to the end portion close to the other of the dome portions 12B to form the helical layer 17A. It should be noted that switching from the braided winding in the dome portion 12B to the helical winding in the straight body portion 12A is performed within an area of a predetermined length in the axial direction near the boundary portion between the dome portion 12B and the straight body portion 12A by switching the arrangement of the plurality of bobbins 42, 44 of the manufacturing machine 40 (
After the end of the helical winding of the fibers 16 around the outer peripheral surface of the straight body portion 12A, the fibers 16 are then wound in a braided manner around the outer peripheral surface of the other of the dome portions 12B to form the braiding layer 17B (third step). Specifically, the fibers 16 are wound in a braided manner successively around the dome portion 12B from the end portion close to the straight body portion 12A to the end portion opposite to the straight body portion 12A to form the braiding layer 17B. It should be noted that switching from the helical winding in the straight body portion 12A to the braided winding in the dome portion 12B is also performed within an area of a predetermined length in the axial direction near the boundary portion between the straight body portion 12A and the dome portion 12B by switching the arrangement of the plurality of bobbins 42, 44 of the manufacturing machine 40 (
It should be noted that the winding angle θ of the fibers 16 wrapped around the one and the other of the dome portions 12B and the straight body portion 12A is within the range of θ=54.7°±10°, for example.
In the present embodiment, at a predetermined position of the lamina of the braiding layer 17B, after the end of the braided winding of the fibers 16, without performing the above-described switching from the braided winding in the dome portion 12B to the helical winding in the straight body portion 12A, continuously therefrom, the fibers 16 are wound in a braided manner around the outer peripheral surface of the straight body portion 12A (specifically, the outer peripheral surface of the laminated portion of the helical layer 17A on the outer peripheral surface of the straight body portion 12A) to form the braiding layer (portion corresponding to 17D of
In other words, at a predetermined position of the lamina of the braiding layer 17B, the fibers 16 are wound in a braided manner successively from the end portion of the one of the dome portions 12B opposite to the straight body portion 12A to the end portion of the other of the dome portions 12B opposite to the straight body portion 12A (across the entire length of the liner 12 in the axial direction) to form the braiding layer (17B, 17D, 17B) (
Through the above-described wrapping of the fibers 16 at one position (in one layer) or multiple positions (in multiple layers) between the laminae (including inside of the innermost layer and outside of the outermost layer) of the helical layer 17A (consisting of about several to several tens of layers, for example), the portion (17D) of the lamina of the braiding layer 17B is interposed continuously from the braiding layer 17B between the laminae of the helical layer 17A.
Through the above-described steps, the fibers 16 are wrapped (in an overlapping or laminating manner in the radial direction) finally into about several to several tens of layers, for example, to form a preform 11 (
(Resin Pouring (Resin Transfer Molding) Step)
The preform 11 (
Specifically, as shown in
In addition, a resin injection pipe (also referred to as a resin injection gate) 82 coupled to a resin injector 81 is embedded in the mold 50 (the upper mold 80 in the illustrated example).
In addition, as shown in
It should be noted that in the example shown in
In addition, in the present embodiment, the runner 72A located at the central portion of the preform 11 in the axial direction is provided with an opening/closing mechanism 76 including an on-off valve and the like to open and close the runner 72A at a predetermined timing. For example, closing the runner 72A by the opening/closing mechanism 76 can interrupt the pouring of the resin 18 from the gate 74A into the mold 50 (cavity).
To impregnate the fiber layer 17 (or the fibers 16 thereof) of the preform 11 with the thermosetting resin 18, first, in a state where the preform 11 is placed in the mold 50 (between the lower mold 60 and the upper mold 80) with the above configuration, which is kept at a predetermined temperature (a temperature equal to or higher than a curing temperature of the thermosetting resin 18) (in other words, after completion of mold clamping), the vacuum pump 61 is controlled for vacuum degassing the mold 50 (
After stopping (or completion of) the above-stated vacuum degassing, the thermosetting resin 18 is poured into the mold 50 by driving the resin injector 81 (
Specifically, first, in a state where the opening/closing mechanism 76 is closed (that is, in a state where the runner 72A is closed and pouring of the resin 18 into the mold 50 from the gate 74A is interrupted), the (uncured) resin 18 flows through the resin injection pipe 82 and is poured (injected) via the runner 72B from the gate 74B into the braiding layer (first fiber layer) 17B on the outer peripheral surface of the dome portion 12B in the mold 50 (cavity) in the axial direction of the preform 11 (
Accordingly, the resin 18 is poured (injected) into the braiding layer (first fiber layer) 17B with large fiber intervals and less dense fibers (low density) in the axial direction of the preform 11, and the resin 18 enters into the fiber layer 17. At this time, since the portion (17D) of the lamina of the braiding layer 17B is interposed continuously from the braiding layer 17B between the laminae of the helical layer 17A (see
After that, the opening/closing mechanism 76 is controlled to be open, and in a state where the opening/closing mechanism 76 is open (in a state where the runner 72A is open), the (uncured) resin 18 flows through the resin injection pipe 82 and is poured (injected) via the runner 72B from the gate 74B into the braiding layer (first fiber layer) 17B on the outer peripheral surface of the dome portion 12B in the mold 50 (cavity) in the axial direction of the preform 11, and also poured (injected) via the runner 72A from the gate 74A into the helical layer (second fiber layer) 17A on the outer peripheral surface of the straight body portion 12A in the mold 50 (cavity) in the radial direction of the preform 11 (
Accordingly, the resin 18 is poured (injected) into the braiding layer (first fiber layer) 17B with large fiber intervals and less dense fibers (low density) in the axial direction of the preform 11 and the resin 18 is poured (injected) into the helical layer (second fiber layer) 17A with small fiber intervals and dense fibers (high density) in the radial direction of the preform 11 (in other words, the resin 18 is poured in both of the axial direction and the radial direction of the preform 11), and the resin 18 enters into the entire fiber layer 17.
It should be noted that a timing of opening the opening/closing mechanism 76 (that is, a timing of pouring the resin 18 via the runner 72A from the gate 74A) may be determined based on a measurement obtained by a pressure sensor for detecting a pressure of the flowing resin 18 or may be determined based on a timing obtained in advance through experiments or the like.
After the laminae of the fiber layer 17 are completed impregnated with the resin 18, resin pouring is stopped, and then heating and curing are performed, whereby a fiber-reinforced resin layer as a reinforcing layer is formed on the outer periphery of the liner 12. As a result, it is possible to obtain the high-pressure tank 10 with excellent corrosion resistance that may achieve weight reduction and low costs and is also easy to carry and handle.
As described above, when a high-pressure tank for fuel cell vehicles is manufactured by the RTM impregnation technology, it is difficult to perform charging, impregnation, and curing of epoxy resin entirely on the thickly-laminated, large tank (with thickly wound carbon fibers) while uniformly applying a resin pressure, and reduction of the productivity and degradation of the tank performance may occur. In addition, since the carbon fibers are laminated thickly on the tank, the resin hardly enters into the innermost layer of the carbon fibers unless the resin is charged at high pressure. This may cause an excessively high pressure in the portion immediately below the gate and the like, resulting in critical quality problems leading to reduction of the productivity and degradation of the tank performance, such as deformation of the resin liner inside of the tank or fiber misalignment.
The present embodiment is directed to significant improvement of resin flowability in a laminate tank, and provides a method for manufacturing a tank including dome portions and a straight body portion. The method includes preparing a liner, winding fibers around the prepared liner, pouring resin into the wound fibers, and curing the poured resin. In the winding, the method winds the fibers around the liner such that the dome portion is less dense than the straight body portion, and in the pouring, the method first pours the resin into the dome portion, and interposes a less dense lamina (continuously from the braiding layer) between laminae of the straight body portion (or the helical layer thereof) in order to improve impregnation properties in a lamina extending direction.
In resin impregnation, the method includes both resin pouring in the lamina extending direction and resin pouring in the thickness direction and the laminating direction, and separately performs the resin pouring in the lamina extending direction and the resin pouring in the thickness direction and the laminating direction. The method first performs the resin pouring in the lamina extending direction and controls impregnation properties to improve the impregnation properties in the entire tank.
The mold 50 includes the opening/closing mechanism 76 in the runner through which resin flows in the RTM mold, and the method first pours resin into the dome portion with a tank structure of less dense fibers and excellent impregnation properties, on which resin flows in the lamina extending direction. After completion of resin impregnation in the lamina extending direction, the method pours resin in the thickness direction with a time difference, whereby, without impairing impregnation properties in the respective directions, it is possible to control the impregnation properties and achieve feedback-automatic-controlling of the resin flowability by observing the resin flow pressure, and the like.
Since the method can pour resin in the lamina extending direction, the resin can enter into the inner layer of the carbon fibers and can enter even farther into the inner layer of the carbon fibers. In addition, it is possible to achieve uniform resin impregnation even when a tank is extended in shape in the axial direction. Moreover, since the resin pouring pressures in different directions (lamina extending direction, thickness direction) will not be interfered with each other, the resin can enter even farther into the inner layer of the carbon fibers. In addition, since the method performs resin pouring in the lamina extending direction with low resistance, it is possible to reduce the movement of the fiber with viscosity of the resin, and reduce the occurrence of fiber misalignment even in the resin pouring in the thickness direction.
With such a configuration, in the epoxy resin impregnation by the RTM impregnation technology, since it is possible to impregnate the entire tank with epoxy resin uniformly and at low pressure in both of the lamina extending direction and the thickness direction, it is possible to achieve an improved performance and a stable quality of the high-pressure tank as well as high-speed resin charging. This can achieve significantly shorter molding cycles of the high-pressure tank.
As described above, according to the present embodiment, providing a portion with less dense fibers (low fiber density) in both of the dome portion 12B and the straight body portion 12A during fiber wrapping can reduce resistance in resin pouring. This can facilitate impregnation of the resin 18, thereby achieving completion of the resin impregnation within a short time.
In addition, since the pouring pressures of the resin 18 in different directions (the axial direction and the lamina extending direction, the radial direction and the thickness direction) will not be interfered with each other during resin pouring, it is possible to achieve completion of the resin impregnation in the inner layer within a short time.
It should be noted that in the foregoing embodiment, although the portion of the lamina of the braiding layer 17B is interposed on the entire surface between the laminae of the helical layer 17A (so as to cover the entire outer peripheral surface of the helical layer 17A) (see
In addition, although the fibers are helically wrapped around the outer peripheral surface of the straight body portion 12A (by helical winding) to form a helical layer, the fibers may be wrapped into a hoop form around the outer peripheral surface of the straight body portion 12A (by hoop winding) to form a hoop layer, for example, by appropriately adjusting a winding angle θ. In addition, it is needless to mention in detail that the way of fiber winding is not limited to the foregoing embodiment as long as a first fiber layer formed by wrapping the fibers around the outer peripheral surface of the dome portion 12B is less dense (i.e., has a lower fiber density) than a second fiber layer formed by wrapping the fibers around the outer peripheral surface of the straight body portion 12A.
In addition, for example, the material of the liner 12 is not limited to liquid crystalline resin. The liner 12 may be made of, for example, another synthetic resin having a gas barrier property, such as high density polyethylene, or a lightweight metal, such as an aluminum alloy. In addition, the liner 12 is not limited to the one manufactured through blow-molding, and may be manufactured through injection molding or the like.
Although the embodiment of the present disclosure has been described in detail above with reference to the drawings, specific structures are not limited thereto, and any design changes that fall within the spirit and scope of the present disclosure are encompassed by the scope of the present disclosure.
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| 2021-137789 | Aug 2021 | JP | national |
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| 20230060650 A1 | Mar 2023 | US |
