JP2020139565A - High pressure tank - Google Patents

Abstract

To suppress variation in strain of a cylindrical part to stabilize quality of a tank.SOLUTION: A high pressure tank (10) comprises a resin liner (11) having a cylindrical part (17) and a pair of side end parts (18, 19) whose diameter decreases from both ends of the cylindrical part toward the outside in an axial direction of the cylindrical part, and a fiber-reinforced resin layer formed so as to cover an outer surface of the liner with resin-impregnated reinforcing fibers. The cylindrical part has a straight part (31) parallel to a central axis of the cylindrical part, and a pair of tapered parts (32, 33) whose diameter decreases from both ends of the straight part toward the pair of side end parts. The fiber-reinforced resin layer has a hoop layer (L1) in which the reinforcing fibers are hoop-wound in a range from the boundary between one tapered part and the straight part to the boundary between the other tapered part and the straight part.SELECTED DRAWING: Figure 3

Description

The present invention relates to a high pressure tank.

As a high-pressure tank, a liner filled with a high-pressure fluid such as gas is reinforced from the outside with reinforcing fibers. In the high-pressure tank manufacturing method, resin-impregnated reinforcing fibers are wound around the outer surface of the liner by a so-called filament winding method (hereinafter referred to as FW method). In the FW method, hoop winding in which the reinforcing fibers are wound around the liner at a winding angle substantially orthogonal to the rotation axis of the liner and helical winding in which the reinforcing fibers are wound around the liner at a winding angle diagonally intersecting the rotation axis are carried out. A fiber reinforced resin layer is formed on the outer surface of the liner.

Usually, the liner has a cylindrical portion and a pair of side ends whose diameters are reduced from both ends of the cylindrical portion toward the axially outward side of the cylindrical portion. As such a liner, one in which tapered portions connected to a pair of side end portions are formed on both end sides of the cylindrical portion (see, for example, Patent Document 1). In the liner described in Patent Document 1, reinforcing fibers are hoop-wound around the outer peripheral surface of the cylindrical portion, and the entire cylindrical portion including the tapered portion is covered with the hoop layer. After the formation of the hoop layer, the reinforcing fibers are helically wound around the outer surface of the entire liner, and the entire liner including the pair of side ends is covered with the helical layer.

Japanese Unexamined Patent Publication No. 2017-145962

However, the cylindrical portion of the liner described in Patent Document 1 is a straight portion parallel to the central axis except for the tapered portions at both ends, and when a hoop layer is formed on the entire cylindrical portion, the radial direction in the tapered portion is formed. Distortion is smaller than the radial distortion in the straight part. Therefore, there is a problem that the radial strain of the cylindrical portion becomes non-uniform and the quality of the high-pressure tank deteriorates.

An object of the present invention is to provide a high-pressure tank capable of stabilizing tank quality by suppressing variation in radial strain of the cylindrical portion.

In order to solve the above problems, the high-pressure tank according to the present invention is a resin liner having a cylindrical portion and a pair of side end portions whose diameters are reduced from both ends of the cylindrical portion toward the outward side in the axial direction of the cylindrical portion. A high-pressure tank including a fiber-reinforced resin layer formed so as to cover the outer surface of the liner with resin-impregnated reinforcing fibers, and the cylindrical portion is a straight portion parallel to the central axis of the cylindrical portion. And a pair of tapered portions whose diameters are reduced from both ends of the straight portion toward the pair of side end portions, and the fiber reinforced resin layer is formed from the boundary between the tapered portion and the straight portion to the other. It is characterized by having a hoop layer in which the reinforcing fibers are hoop-wound in a range up to the boundary between the tapered portion and the straight portion.

According to the present invention, the reinforcing fibers are not hoop-wound around the tapered portion, and the reinforcing fibers are hoop-wound around the straight portion to form a hoop layer. Since the tapered portion has a shape that is less likely to cause distortion than the straight portion, variation in radial distortion of the cylindrical portion can be suppressed when the high-pressure tank is filled with fuel gas, and the quality of the high-pressure tank can be stabilized. In addition, the amount of reinforcing fibers for the cylindrical portion is reduced, and the manufacturing cost of the high-pressure tank can be reduced.

It is a schematic cross-sectional view of the high pressure tank which concerns on this embodiment. It is a partially enlarged view of the liner of the high pressure tank which concerns on this embodiment. It is explanatory drawing of the liner of the high pressure tank which concerns on this embodiment, (A) shows the partial enlarged view of liner, (B) shows the strain distribution map of liner. It is explanatory drawing of the liner of the high pressure tank which concerns on a comparative example, (A) shows the partial enlarged view of liner, (B) shows the strain distribution map of liner. It is a flowchart which shows an example of the manufacturing method of the tank which concerns on this embodiment.

Hereinafter, the present embodiment will be described. FIG. 1 is a schematic cross-sectional view of the high pressure tank according to the present embodiment. FIG. 2 is a partially enlarged view of the liner of the high pressure tank according to the present embodiment. In the following, a fuel tank for storing fuel gas such as hydrogen in a fuel cell in an in-vehicle fuel cell system as a high-pressure tank will be described as an example, but the high-pressure tank is used for any purpose other than the fuel cell system. You may.

[About high pressure tank]
As shown in FIG. 1, the high-pressure tank 10 has a tank body 13 in which the outer surface of the liner 11 which is the base material of the tank is coated with the fiber reinforced resin layer 12. The tank body 13 has an outer surface shape in which a pair of dome portions 15 and 16 are hemispherically bulged from both ends of the tubular body portion 14. A pair of bases 21 and 26 are provided at the apex points of the dome portions 15 and 16. A through hole 24 is formed in one of the bases 21, and a valve (not shown) attached to the through hole 24 releases and inflows gas into the tank body 13. The other base 26 does not penetrate, and the tank body 13 is sealed by the base 26.

The liner 11 serves as a base material for the high-pressure tank 10, and is formed in a hollow shape so as to have a fuel gas storage space 20. The liner 11 has a cylindrical portion 17 and a pair of side end portions 18 and 19 that bulge from the cylindrical portion 17 so as to reduce the diameter of the cylindrical portion 17 in the axial direction. As the resin material of the liner 11, for example, a resin such as polyamide, ethylene vinyl alcohol copolymer, or polyethylene can be used. In the liner 11, in addition to hydrogen gas as the fuel gas, for example, various compressed gases such as CNG (compressed natural gas), various liquefied gases such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas), and various other types. Pressurized material may be filled.

In the fiber reinforced resin layer 12, a band-shaped reinforcing fiber bundle (not shown) impregnated with an uncured resin (uncured thermosetting resin) is wound around a liner 11, and the uncured resin is cured by heating. Is formed by. The fiber-reinforced resin layer 12 is formed by hoop-wrapping a reinforcing fiber bundle around the cylindrical portion 17 of the liner 11 to form a hoop layer L1 and helically winding the reinforcing fiber bundle around the entire liner 11. It has a helical layer L2. The hoop layer L1 secures the radial strength of the cylindrical portion 17 of the liner 11, and the helical layer L2 secures the axial strength of the liner 11.

The hoop winding is a winding mode in which a reinforcing fiber bundle is wound around the liner 11 at a winding angle substantially orthogonal to the rotation axis (central axis) CX of the liner 11. The helical winding is a winding mode in which a reinforcing fiber bundle is wound around the liner 11 at a winding angle that diagonally intersects the rotation axis CX of the liner 11. As the reinforcing fiber, carbon fiber, glass fiber, aramid fiber and the like may be adopted. A thermoplastic resin may be adopted as the uncured resin. When a thermoplastic resin is used as the uncured resin, the reinforcing fiber bundle is wound around the outer surface of the liner 11 in a softened state, and then the thermoplastic resin is cured by allowing to cool.

One base 21 is made of a metal such as aluminum or an aluminum alloy. On the other hand, the base 21 has a flange portion 23 formed on the outer periphery of the tubular portion 22 as the main body, and is attached to the liner 11 so that a part of the tubular portion 22 protrudes from the dome portion 15. A valve (not shown) for filling and discharging fuel gas for the storage space 20 is attached to the through hole 24 inside the tubular portion 22. The other base 26 is made of a metal such as aluminum or an aluminum alloy. The other base 26 is formed to have substantially the same outer shape as the one base 21, but differs from the one base 21 in that the inside of the tubular portion 27 is closed.

As a result of diligent studies on the strain generated in the liner 11, the present inventor has obtained the following findings and found the present invention.

[Distortion that occurs in the liner]
As shown in FIG. 2, the resin liner 11 is formed by injection molding of resin, unlike a metal liner such as aluminum. Therefore, in the manufacturing process of the liner 11, the tapered portions 32 and 33 (the tapered portion 33 is FIG. 3) connected to the side end portions 18 and 19 (see FIG. 3B for the side end portions 19) at both ends of the cylindrical portion 17. (See (B)) is formed. More specifically, the tapered portion 32 is formed by a draft (for example, 0.5 degree) for pulling out the mold at the time of injection molding of the liner 11. Therefore, the cylindrical portion 17 has a straight portion 31 parallel to the rotation axis CX of the cylindrical portion 17 and a pair of tapered portions 32, 33 whose diameters are reduced from both ends of the straight portion 31 toward the pair of side end portions 18, 19. It is composed of and.

When the hoop layer L1 is uniformly formed on the entire cylindrical portion 17 of the liner 11 (see FIG. 4), the strength of the cylindrical portion 17 is guaranteed, but the cylindrical portion 17 is filled with the fuel gas to the liner 11. The quality of the high-pressure tank 10 is not stable due to variations in the radial strain of the cylinder. Specifically, the radial strain in the tapered portions 32 and 33 at both ends of the cylindrical portion 17 is smaller than the radial strain in the straight portion 31 of the cylindrical portion 17. This is because when fuel gas is supplied to the high-pressure tank 10, the taper portions 32 and 33 start to expand from the vicinity of the center of the straight portion 31, and the taper portions 32 and 33 expand by the amount that the expansion of the taper portions 32 and 33 is delayed from the expansion near the center. It is thought that this is because

The radial stress of the cylindrical portion 17 is expressed by the following equation (1), where σ is the stress, r is the outer diameter of the cylindrical portion 17, and ε is the radial strain of the cylindrical portion 17. That is, as the outer diameter of the cylindrical portion 17 decreases, the radial distortion of the cylindrical portion 17 decreases. As described above, the outer diameter of the straight portion 31 is formed to be constant as a whole, whereas the outer diameter of the tapered portion 32 decreases from the straight portion 31 toward the side end portion 18. Therefore, the radial strain in the tapered portion 32 is smaller than the radial strain in the straight portion 31.
σ ＝ πε / r ² … (1)

By forming the tapered portion 32 in the cylindrical portion 17 in this way, the radial distortion generated in the tapered portion 32 is reduced. The small radial strain of the cylindrical portion 17 indicates that the cylindrical portion 17 is not easily deformed and has high strength. Here, the present inventor prepared a high-pressure tank in which the hoop layer L1 (see FIG. 3A) was formed only on the straight portion 31, and measured the radial strain distribution generated in the cylindrical portion 17. It was found that the variation in distortion of the entire 17 was suppressed. Further, the high-pressure tank in which the hoop layer L1 is not formed on the tapered portion 32 also has the same strength as the high-pressure tank in which the hoop layer L1 is formed on the tapered portion 32.

Therefore, in the high-pressure tank 10 of the present embodiment, by forming the hoop layer L1 (see FIG. 3A) only in the straight portion 31, the radial strains of the tapered portion 32 and the straight portion 31 are made uniform. The quality of the high-pressure tank 10 is stabilized. Since sufficient strength can be obtained without winding the reinforcing fiber bundle around the tapered portion 32, the consumption of the reinforcing fiber bundle can be reduced and the manufacturing cost of the high-pressure tank 10 can be reduced. Further, since the hoop layer L1 does not protrude toward the side end portions 18 and 19, it is not necessary to accurately measure the end position of the hoop layer L1. Therefore, the measurement equipment at the end position of the hoop layer L1 becomes unnecessary, and the manufacturing cost of the high pressure tank 10 can be further reduced.

Hereinafter, the liner on which the hoop layer is formed will be described. 3A and 3B are explanatory views of a liner of a high-pressure tank according to the present embodiment, FIG. 3A shows a partially enlarged view of the liner, and FIG. 3B shows a strain distribution map of the liner. 4A and 4B are explanatory views of a liner of a high-pressure tank according to a comparative example, FIG. 4A shows a partially enlarged view of the liner, and FIG. 4B shows a strain distribution map of the liner.

[Distortion of liner of high pressure tank of this embodiment]
As shown in FIG. 3A, the hoop layer L1 is formed only on the straight portion 31 of the cylindrical portion 17 of the liner 11. More specifically, the hoop layer L1 is formed in a range from the boundary between one tapered portion 32 and the straight portion 31 to the boundary between the other tapered portion 33 (see FIG. 3B) and the straight portion 31. Only the straight portion 31 of the cylindrical portion 17 is covered by the hoop layer L1, and the tapered portion 32 is exposed from the hoop layer L1. The strength of the straight portion 31 is reinforced by the hoop layer L1, and the hoop layer L1 suppresses the radial deformation of the straight portion 31 from the outside.

The one-sided end position of the hoop layer L1 is positioned at the boundary between the tapered portion 32 and the straight portion 31. Since the reinforcing fiber bundle is not wound around the tapered portion 32, the end position of the hoop layer L1 does not protrude from the tapered portion 32 to the side end portion 18. Therefore, as in the comparative example described later, it is not necessary to wind the reinforcing fiber bundle around the cylindrical portion 17 while measuring the end position of the hoop layer L1 by the measuring equipment at the time of forming the hoop layer L1. Although the description is omitted, the same applies to the position of the other end of the hoop layer L1. Further, the boundary between the tapered portions 32 and 33 and the straight portion 31 may be detected optically by image processing or the like, or may be detected mechanically.

Here, as shown in FIG. 3B, the radial strain distribution of the cylindrical portion 17 in which the hoop layer L1 was formed only on the straight portion 31 was measured. In this case, the tapered portion 32 on one end side of the cylindrical portion 17 is measured at the measurement position Pa, the one end side of the straight portion 31 adjacent to the tapered portion 32 is measured at the measurement position Pb, and about 1/1 of the total length of the straight portion 31 from one end of the straight portion 31. The four positions were defined as the measurement position Pc, and the measurement position Pd was defined as about 3/4 of the total length of the straight portion 31 from one end of the straight portion 31. A measurement result was obtained that the radial strain at the measurement position Pa of the tapered portion 32 was substantially equal to the radial strain at the measurement position Pb-Pd of the straight portion 31.

As described above, even if the hoop layer L1 is not formed on the tapered portion 32, the tapered portion 32 is suppressed in radial distortion due to its unique shape, and the hoop layer L1 is formed on the straight portion 31. The hoop layer L1 suppresses the radial distortion of the straight portion 31. Therefore, the quality of the high-pressure tank 10 is stabilized by making the strain distributions of the tapered portion 32 and the straight portion 31 substantially uniform in the radial direction. Further, since it is not necessary to wind the reinforcing fiber bundle around the tapered portion 32, the consumption of the reinforcing fiber bundle is suppressed, and expensive measuring equipment for measuring the end position of the hoop layer L1 is not required. The manufacturing cost of the high pressure tank 10 can be reduced.

[Distortion of liner of high-pressure tank in comparative example]
On the other hand, in the comparative example, as shown in FIG. 4A, the hoop layer L1 is formed on the entire cylindrical portion 17 of the liner 11. More specifically, the hoop layer L1 is formed in the range from the boundary between one side end portion 18 and the tapered portion 32 to the boundary between the other side end portion 19 and the tapered portion 33 (see FIG. 4B). .. By covering the straight portion 31 and the tapered portions 32 and 33 with the hoop layer L1, the strength of not only the straight portion 31 but also the tapered portions 32 and 33 is reinforced by the hoop layer L1. The hoop layer L1 uniformly suppresses the radial deformation of the tapered portions 32 and 33 and the straight portion 31 from the outside.

The one-sided end position of the hoop layer L1 is positioned at the boundary between the side end portion 18 and the tapered portion 32, that is, the so-called R stop. If the end position of the hoop layer L1 protrudes greatly from the tapered portion 32 to the side end portion 18, there is a problem that the quality of the high pressure tank 10 deteriorates. Therefore, when forming the hoop layer L1, the hoop layer L1 is strengthened to the tapered portion 32 while measuring the end position of the hoop layer L1 so that the end position of the hoop layer L1 does not protrude from the tapered portion 32 to the side end portion 18. A bundle of fibers is wrapped around it. Although the description is omitted, the same applies to the position of the other end of the hoop layer L1.

Here, as shown in FIG. 4 (B), the radial strain distribution of the cylindrical portion 17 in which the hoop layer L1 (see FIG. 4A) was formed as a whole was measured. In this case, the tapered portion 32 on one end side of the cylindrical portion 17, one end side of the straight portion 31 adjacent to the tapered portion 32, about 1/4 of the total length of the straight portion 31 from one end of the straight portion 31, and one end of the straight portion 31. The measurement position Pa-Pd was set to about 3/4 of the total length of the straight portion 31. A measurement result was obtained that the radial strain at the measurement position Pa of the tapered portion 32 was smaller than the radial strain at the measurement position Pb-Pd of the straight portion 31.

In this way, the radial distortion of the cylindrical portion 17 on the tapered portion 32 side is relatively small across the boundary between the tapered portion 32 of the cylindrical portion 17 and the straight portion 31, and the diameter of the cylindrical portion 17 on the straight portion 31 side. The distortion in the direction is relatively large. Therefore, the strain distribution in the radial direction varies between the tapered portion 32 and the straight portion 31, and the quality of the high-pressure tank 10 is not stable. Further, the consumption of the reinforcing fiber bundle increases by the amount that the reinforcing fiber bundle is wound around the tapered portions 32 and 33, and an expensive measuring facility for measuring the end position of the hoop layer L1 is required. Therefore, the high pressure tank 10 The manufacturing cost is high.

Subsequently, a method for manufacturing the tank will be described. FIG. 5 is a flowchart showing an example of a tank manufacturing method according to the present embodiment. In addition, in FIG. 5, the reference numeral of FIG. 3 is appropriately used for description.

As shown in FIG. 5, first, a hoop layer forming step of forming the hoop layer L1 with respect to the straight portion 31 of the cylindrical portion 17 is carried out (step S01). In the hoop layer forming step, an eyepiece (not shown) that guides the reinforcing fiber bundle to the liner 11 is positioned near the liner 11, and the liner 11 rotates around the rotation axis CX, so that the reinforcing fiber bundle is rotated from the eyekuchi. It is wound around the liner 11 at a winding angle substantially orthogonal to the CX. At this time, the dagger reciprocates along the rotation axis CX of the liner 11, so that the reinforcing fiber bundle is wound around the straight portion 31 to form the hoop layer L1.

More specifically, as the dagger moves, the reinforcing fiber bundle is wound from the initial position of the straight portion 31 toward one of the tapered portions 32. When the reinforcing fiber bundle is wound up to the boundary between the one tapered portion 32 and the straight portion 31, the moving direction of the dagger is reversed and the reinforcing fiber bundle is wound toward the other tapered portion 33. When the reinforcing fiber bundle is wound to the boundary between the other tapered portion 33 and the straight portion 31, the moving direction of the dagger is reversed and the reinforcing fiber bundle is wound toward the one tapered portion 32. By repeating this reciprocating operation of the dagger, the hoop layer L1 is formed only on the straight portion 31.

Next, a helical layer forming step of forming the helical layer L2 over the entire liner 11 is carried out (step S02). In the helical layer forming step, the liner 11 rotates around the rotation axis, so that the reinforcing fiber bundle is wound around the liner 11 at a winding angle that diagonally intersects the rotation axis CX from the dagger. At this time, the dagger reciprocates between both ends of the liner 11 in the rotation axis direction, so that the reinforcing fiber bundle is wound around the entire liner 11 to form the helical layer L2. Next, a curing step of curing the uncured resin impregnated in the reinforcing fibers by heating is performed (step S03). As a result, the reinforcing fiber bundles wound around the liner 11 are adhered to each other, and the fiber reinforced resin layer 12 is formed on the outer surface of the liner 11.

In this way, the fiber reinforced resin layer 12 having the hoop layer L1 around which the reinforcing fiber bundle is wound is formed in the range from the boundary between the one tapered portion 32 and the straight portion 31 to the boundary between the other tapered portion 33 and the straight portion 31. Will be done. By forming the hoop layer L1 on the straight portion 31, the radial strain of the liner 11 in the straight portion 31 and the radial strain of the liner 11 in the tapered portions 32 and 33 are uniform when the high pressure tank 10 is filled with fuel gas. Can be approached to. Although the hoop layer L1 is not formed on the tapered portions 32 and 33, the strength of the high pressure tank 10 does not decrease.

As described above, in the high-pressure tank 10 of the present embodiment, the reinforcing fiber bundle is not hoop-wound around the tapered portion 32, and the reinforcing fiber bundle is hoop-wound around the straight portion 31 to form the hoop layer L1. There is. Since the tapered portion 32 has a shape that is less likely to cause distortion than the straight portion 31, variation in radial distortion of the cylindrical portion 17 is suppressed when the high-pressure tank 10 is filled with fuel gas, and the quality of the high-pressure tank 10 is stabilized. Can be done. Further, the amount of reinforcing fibers with respect to the cylindrical portion 17 is reduced, and the manufacturing cost of the high-pressure tank 10 can be reduced.

In the present embodiment, the strip-shaped reinforcing fiber bundle is wound around the liner 11 to form the fiber reinforced resin layer 12, but the configuration is not limited to this. The fiber-reinforced resin layer 12 may be formed by winding the reinforcing fibers around the outer surface of the liner 11, and the reinforcing fibers may not be bundled in a band shape.

Moreover, although this embodiment has been described, as another embodiment, the embodiment and the modification may be combined in whole or in part. Further, the technique of the present disclosure is not limited to the present embodiment, and may be variously modified, replaced, or modified without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in another way by the advancement of the technology or another technology derived from it, it may be carried out by that method. Therefore, the claims cover all embodiments that may be included within the scope of the technical idea.

10: High pressure tank, 11: Liner, 12: Fiber reinforced resin layer, 17: Cylindrical part, 18, 19: Side end part, 31: Straight part, 32, 33: Tapered part, CX: Rotation axis (central axis), L1: Hoop layer

Claims (1)

A resin liner having a cylindrical portion and a pair of side end portions whose diameters are reduced from both ends of the cylindrical portion toward the outside in the axial direction of the cylindrical portion, and resin-impregnated reinforcing fibers cover the outer surface of the liner. It is a high-pressure tank provided with a fiber-reinforced resin layer formed in
The cylindrical portion has a straight portion parallel to the central axis of the cylindrical portion and a pair of tapered portions whose diameters are reduced from both ends of the straight portion toward the pair of side end portions.
The fiber-reinforced resin layer is characterized by having a hoop layer in which the reinforcing fibers are hoop-wound in a range from the boundary between one tapered portion and the straight portion to the boundary between the other tapered portion and the straight portion. High pressure tank.

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