Pressure vessel liners

Abstract

To provide a technology which inhibits peeling of a liner in joint parts between dome parts and a body part.SOLUTION: A liner of a pressure container disclosed by the specification is realized in a pressure container having a cylindrical body part and a pair of dome parts provided at both axial ends of the body part. The liner of the pressure container includes: a first liner located in the body part; and second liners respectively located at the dome parts and having a thickness larger than that of the first liner. An end of the first liner is displaced to the inner side toward a center axis of the body part. An end surface of the second liner is joined contacting with an outer surface of the end displaced to the inner side of the first liner from the axial direction.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a liner for a pressure vessel having a cylindrical body portion and a pair of dome portions provided on both axial ends of the body portion. [Background technology]

[0002] In the pressure vessel liner of Patent Document 1, the second liner located in the dome section is inserted inside the first liner located in the body section. That is, in the pressure vessel liner, the second liner overlaps with the first liner in the radial direction of the body section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-112256 A Summary of the Invention [Problem to be solved by the invention]

[0004] At low temperatures, the liner of the pressure vessel shrinks. The thickness of the second liner located in the dome section is greater than the thickness of the first liner located in the body section. Therefore, at low temperatures, the amount by which the second liner shrinks differs from the amount by which the first liner shrinks. As a result, in the liner of the pressure vessel of Patent Document 1, at low temperatures, the thicker second liner may deform the first liner radially inward. In this state, when high-pressure gas is filled inside the liner, there is a risk that the first and second liners will peel off from each other at the joint between them. This specification provides a technology for suppressing peeling of the liners at the joint between the first and second liners. [Means for solving the problem]

[0005] The liner of a pressure vessel disclosed in this specification is embodied in a pressure vessel having a cylindrical body portion and a pair of dome portions provided at both axial ends of the body portion. The liner of the pressure vessel includes a first liner located in the body portion and a second liner located in the dome portion and having a thickness greater than that of the first liner. An end portion of the first liner is displaced inward toward the central axis of the body portion. An end face of the second liner is abutted against and joined to an outer surface of the end portion of the first liner displaced inward from the axial direction.

[0006] In the pressure vessel described above, the first liner end is displaced inward toward the central axis of the body, and the second liner is joined to the outer surface of the end in an axial direction. This allows the end surface of the second liner, which is thicker than the first liner, to be firmly fixed over a wide area to the outer surface of the end of the first liner, which is displaced inward toward the central axis. In addition, with this configuration, the first liner and the second liner do not overlap in the radial direction. Therefore, the influence of the contraction of the first liner and the second liner, which have different thicknesses, at low temperatures can be suppressed. As a result, even if gas is filled at low temperatures, the first liner and the second liner are unlikely to peel off from each other. With the liner of the pressure vessel disclosed in this specification, peeling of the liners at the joint between the first liner and the second liner can be suppressed.

[0007] Details and further improvements of the technology disclosed in this specification are described in the following "Forms for Carrying Out the Invention". [Brief description of the drawings]

[0008] [Figure 1] 1 shows a perspective view of a pressure vessel 2 including a liner 4 according to an embodiment of the present invention. [Diagram 2] An exploded view of the liner 4 is shown. [Diagram 3] 3 shows a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] A cross-sectional view of the process of forming the end 12 of the first liner 10 is shown. [Diagram 5] 1 shows a cross-sectional view of a process of bonding the first liner 10 and the second liner 14e. [Figure 6] 6 shows a cross-sectional view of a step subsequent to the step in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Example) FIG. 1 shows a perspective view of a pressure vessel 2 including a liner 4 according to an embodiment. The pressure vessel 2 is mounted on, for example, a fuel cell vehicle (not shown). The pressure vessel 2 stores high-pressure hydrogen gas used for generating electricity in the fuel cell vehicle. The pressure vessel 2 has a cylindrical body 2c and a pair of dome sections 2d provided at both ends of the body 2c. Each of the pair of dome sections 2d is curved inwardly from the end of the body 2c in a spherical shape (i.e., dome-shaped). In addition to the liner 4, the pressure vessel 2 includes a reinforcing layer 6, a mouthpiece 8v, and an end boss 8e. Hereinafter, the direction parallel to the central axis CL of the body 2c (i.e., the positive and negative directions of the X-axis in the coordinate system in the figure) is referred to as the axial direction.

[0010] The liner 4 is made of resin and forms a space for sealing hydrogen gas. The reinforcing layer 6 is a layer that reinforces the liner 4 by covering the outer surface of the liner 4. In this embodiment, the reinforcing layer 6 is wound around the outer surface of the liner 4 by a filament winding method. In a modified example, the reinforcing layer 6 may be wound around the outer surface of the liner 4 by another method.

[0011] The nozzle 8v is made of metal and is provided at one axial end of the liner 4 (i.e., the right end in FIG. 1). The nozzle 8v has a through hole that communicates between the inside and outside of the liner 4. Hydrogen gas in the pressure vessel 2 is released to the outside and hydrogen gas is supplied from the outside to the pressure vessel 2 through the through hole of the nozzle 8v. The end boss 8e is made of metal and is provided at the other axial end of the liner 4 (i.e., the left end in FIG. 1). Unlike the nozzle 8v, the end boss 8e does not have a through hole.

[0012] The detailed structure of the liner 4 will be described with reference to FIG. 2. FIG. 2 shows an exploded view of the liner 4. The liner 4 includes a first liner 10 and a pair of second liners 14v, 14e. The first liner 10 has a cylindrical shape and extends in the axial direction. The first liner 10 constitutes the body portion 2c (see FIG. 1) of the pressure vessel 2. The pair of second liners 14v, 14e are joined to the nozzle 8v and the end boss 8e, respectively. The pair of second liners 14v, 14e are curved in a dome shape toward the nozzle 8v and the end boss 8e, respectively. The pair of second liners 14v, 14e are joined to the end 12 of the first liner 10 in the axial direction. This completes the liner 4 that seals hydrogen gas inside.

[0013] A method for manufacturing the liner 4 will be described with reference to Figs. 3 to 6. In this specification, a method for joining the first liner 10 and the second liner 14e will be described in particular. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2, and is an enlarged view showing the relationship between the end 12 of the first liner 10 and the end face 18 of the second liner 14e. Note that, although a method for joining the first liner 10 and one of the second liners 14e will be described below, the first liner 10 and the other second liner 14v are also joined in a similar manner.

[0014] As shown in FIG. 3, the end 12 of the first liner 10 is curved toward the central axis CL. That is, the end 12 of the first liner 10 is displaced inward toward the central axis CL. As a result, the outer surface 16 of the end 12 faces the second liner 14e. The first liner 10 is composed of a first resin layer 10a and a second resin layer 10b. The first liner 10 is formed by simultaneously extruding three layers, the first resin layer 10a, the second resin layer 10b, and the first resin layer 10a, in that order, from a multi-layer die. The first liner 10 is formed by so-called multi-layer co-extrusion molding. The first liner 10, in which the three layers are laminated, has a first thickness T1. The first resin layer 10a and the second resin layer 10b are each composed of a different resin. The first liner 10 can ensure a relatively high rigidity even with a relatively small first thickness T1 by laminating a plurality of resin layers 10a, 10b.

[0015] On the other hand, the second liner 14e is made of a single resin. The second liner 14e has a relatively complicated shape that is curved in a dome shape. The second liner 14e is formed by injection molding. The second liner 14e has a second thickness T2. As shown in FIG. 3, the second thickness T2 is greater than the first thickness T1. The second liner 14e made of a single resin ensures high rigidity due to the second thickness T2 being greater than the first thickness T1. The second liner 14e is made of the same resin as the first resin layer 10a. The end surface 18 of the second liner 14e faces the outer surface 16 of the end 12 of the first liner 10.

[0016] Here, referring to FIG. 4, a process of forming the end 12 of the first liner 10 will be described. The end 12 of the first liner 10 formed by multi-layer co-extrusion molding is pressed against the mold 20. Furthermore, while the end 12 is pressed against the mold 20, the mold 20 is heated and then cooled. As a result, the end 12 of the first liner 10 is curved inward toward the central axis CL. Since the first liner 10 has a relatively simple cylindrical shape, the production efficiency of the first liner 10 can be improved by forming it by multi-layer co-extrusion molding. Furthermore, by curving the end 12 inward, the rigidity of the end 12 of the first liner 10 can be improved.

[0017] 5 and 6, a process of joining the first liner 10 and the second liner 14e will be described. As shown in FIG. 5, the second liner 14e abuts against the outer surface 16 of the end portion 12 of the first liner 10 in the axial direction. As described above, the end portion 12 of the first liner 10 is displaced inward. Therefore, the length of the outer surface 16 of the end portion 12 of the first liner 10 becomes substantially the same as the thickness of the end surface 18 of the second liner 14e (i.e., the second thickness T2).

[0018] As a result, the end surface 18 of the second liner 14e having the second thickness T2 abuts over a wide area against the outer surface 16 of the end portion 12 of the first liner 10. This allows the end surface 18 of the second liner 14e to be firmly bonded to the outer surface 16 of the end portion 12 of the first liner 10.

[0019] Then, as shown in FIG. 6, the joint between the first liner 10 and the second liner 14e is heated. As a result, the end surface 18 of the second liner 14e and the end 12 of the first liner 10 are both melted. Then, the liners 10 and 14e are bonded to each other by cooling. As described above, the first resin layer 10a forming the outer surface 16 of the first liner 10 and the second liner 14e are made of the same resin. Therefore, compared to a configuration in which different resins are bonded, it is relatively easy to bond the end surface 18 of the second liner 14e to the outer surface 16 of the first liner 10.

[0020] As described above, since both the liners 10 and 14e are made of resin, when the ambient temperature of the pressure vessel 2 (see FIG. 1) changes, the liners 10 and 14e are significantly deformed. For example, at low temperatures, the liners 10 and 14e having different thicknesses shrink by different amounts. As shown in FIG. 5 and FIG. 6, in the liner 4 of this embodiment, the end face 18 of the second liner 14e is joined to the outer surface 16 of the first liner 10 in the axial direction. Therefore, the first liner 10 and the second liner 14e do not overlap in the radial direction (i.e., the vertical direction of the paper surface of FIG. 6). Therefore, even if the liners 10 and 14e having different thicknesses shrink by different amounts at low temperatures, the joints of the liners 10 and 14e are unlikely to deform in the radial direction. Therefore, even if hydrogen gas is filled into the liner 4 at low temperatures, radial load is unlikely to be applied to the joints of the liners 10, 14e. As a result, radial separation of the liners 10, 14e can be suppressed when hydrogen gas is filled into the liner 4 at low temperatures.

[0021] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Modifications of the above embodiments are listed below.

[0022] (Variation 1) The first liner 10 does not have to have a three-layer structure. For example, the first liner 10 may have a single-layer structure of the first resin layer 10a. In addition, the end portion 12 of the first liner 10 does not have to be formed by the method of FIG. 4. For example, the first liner 10 may be formed by injection molding.

[0023] (Variation 2) The radial length of the outer surface 16 of the end 12 of the first liner 10 does not have to be approximately equal to the second thickness T2. The radial length of the outer surface 16 may be longer or shorter than the second thickness T2.

[0024] The technical elements described in this specification or drawings have technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. [Explanation of symbols]

[0025] 2: Pressure vessel 2c: body part 2d: Dome section 4: Lina 6: Reinforcement layer 8e: End Boss 8v : Base 10: First Liner 10a: First resin layer 10b: second resin layer 12: End 14e, 14v: second liner 16: External surface 18: End face 20: Mold CL: Central axis T1: First thickness T2: Second thickness

Claims

[Claim 1] A liner for a pressure vessel, comprising: The pressure vessel includes a cylindrical body portion and a pair of dome portions provided at both ends of the body portion in an axial direction, The liner comprises: It is made of resin and reinforced with a reinforcing layer on the outside. a first liner located in the fuselage; a second liner located in the dome portion and having a thickness greater than that of the first liner; an end of the first liner is displaced inwardly toward a central axis of the fuselage; A liner for a pressure vessel, wherein an end face of the second liner is abutted and joined in the axial direction to an outer surface of the end portion of the first liner that displaces inward.

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