JP2009121652A - Pressure vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure vessel capable of restraining stress concentration on a CFRP layer over a relatively long period. <P>SOLUTION: This pressure vessel 1 is provided by interposing a ring-shaped GFRP layer 90 in at least a part of a contact part between a base 3 and the CFRP layer 12. The GFRP layer 90 is preferably laminated in an artificially isotropic shape, and is preferably arranged to be sandwiched by a collar part 34 of the base 3 and the CFRP layer 12. The GFRP layer 90 is molded by a braiding method or a hand lay-up method, and is preferably formed thicker in a part positioned on the tip side of the collar part 34 more than a part positioned on its base end side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pressure vessel mounted on, for example, a fuel cell system.

  In a pressure vessel applied to the fuel cell system, for example, hydrogen gas having a high pressure of 35 MPa or 70 MPa is stored. Conventionally, as a pressure vessel for storing CNG gas or the like, for example, those described in Patent Documents 1 and 2 are known.

  The pressure vessel described in Patent Document 1 is obtained by reinforcing the outer surface of a liner layer made of polyethylene resin with a CFRP (Carbon Fiber Reinforced Plastics) layer, and its mouth portion is formed of a base. An elastic sealing material made of rubber is provided between the flange portion of the base and the inner surface of the liner layer, and the airtightness between the liner layer and the base is enhanced.

Similarly to the above, the pressure vessel described in Patent Document 2 is such that the outer surface of the liner layer is reinforced with the CFRP layer, but the flange portion of the base protruding radially outward is sandwiched between the liner layer and the CFRP layer. ing.
Japanese Patent Laying-Open No. 2005-48918 (FIG. 1) Japanese Patent Laid-Open No. 10-231997 (FIG. 1)

In the structure of the pressure vessel described in Patent Document 2, stress concentrates on the portion of the CFRP layer that is in contact with the distal end portion of the flange portion, and there is a possibility that a crack or the like is generated. This is because it is considered that the base is pushed outward in the axial direction by the internal pressure of the container, so that the tip of the collar comes into strong contact with the inner surface of the CFRP layer.
But if the elastic sealing material of patent document 1 is provided in the front-end | tip part of a collar part, it will not be able to suppress the stress concentration to a CFRP layer. However, when the internal pressure of the container is high, the rubber-made elastic sealing material may be destroyed in a relatively short period of time due to repeated pressure loads, and the expected stress relaxation effect may not be obtained.

  An object of this invention is to provide the pressure vessel which can suppress the stress concentration to a CFRP layer over a comparatively long period of time.

  In order to achieve the above object, the pressure vessel of the present invention has a base and a CFRP layer in contact with the outer peripheral surface of the base, and at least part of the contact portion between the base and the CFRP layer has a ring-shaped GFRP. (Class Fiber Reinforced Plastics) layer is interposed.

  According to the present invention, even when the die receives the internal pressure of the container, the ring-shaped GFRP layer can suppress the load caused by the internal pressure from acting directly on the CFRP layer. Thereby, the stress of the part of the CFRP layer which a nozzle contacts can be relieved, and the stress concentration to the CFRP layer which is a strength member of the pressure vessel can be suppressed in the circumferential direction. Moreover, since the GFRP layer which was excellent in the compressive strength and the fatigue strength compared with rubber | gum is used as the member to interpose, the stress relaxation effect over a long term can be ensured.

  Preferably, the GFRP layer is formed by quasi-isotropic lamination. According to this configuration, the elastic characteristics are the same in all directions of the GFRP layer, which is suitable for stress relaxation.

  Preferably, the pressure vessel further includes a liner layer whose outer peripheral side is covered with a CFRP layer, and the base has a collar portion disposed so as to be sandwiched between the CFRP layer and the liner layer. The GFRP layer is preferably provided so as to be sandwiched between the collar portion and the CFRP layer. According to such a configuration, the portion of the CFRP layer where stress concentration is likely to occur can be effectively relaxed. Moreover, it can suppress that a nozzle | cap | die slips out by a collar part.

  More preferably, in the GFRP layer, the portion located on the distal end side of the buttocks may be thicker than the portion located on the proximal end side. According to this configuration, it is possible to effectively relieve the portion where stress concentration is most likely to occur. Moreover, compared with the case where all GFRP layers are formed with the same thickness, the GRFR layer can be reduced in weight, and the pressure vessel can be reduced in weight.

  More preferably, it is good for the collar part to have the front-end | tip part formed thinner than the base end part.

  Preferably, a recessed portion or a stepped portion for providing a GFRP layer is formed at the distal end portion of the collar portion. According to this configuration, the GFRP layer can be easily provided.

  More preferably, the outer surface of the GFRP layer is flush with the outer surface of the liner layer in a state where the GFRP layer is provided in the recess or step. According to this configuration, since there is no step on the outer surface between the GFRP layer and the liner layer, the CFRP layer can be positioned on both the outer surfaces without any step. Thereby, it is possible to provide the GFRP layer while maintaining the strength of the CFRP layer.

  Preferably, the outer surface of the GFRP layer is flush with the outer surface of the base end portion of the collar portion in a state where the GFRP layer is provided in the recess or step. According to this configuration, as described above, it is possible to provide the GFRP layer while maintaining the strength of the CFRP layer.

  Preferably, the GFRP layer is formed by a braiding method or a hand layup method. The GFRP layer is preferably formed over the circumferential direction of the axis of the die.

  According to the pressure vessel of the present invention, since the GFRP layer is provided, stress concentration on the CFRP layer can be suppressed over a long period of time.

  Hereinafter, a pressure vessel according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings. Here, a high-pressure tank will be described as an example of the pressure vessel.

FIG. 1 is a view showing a fuel cell vehicle equipped with a high-pressure tank according to the present embodiment.
The fuel cell automobile 100 has, for example, three high-pressure tanks 1 mounted on the rear part of the vehicle body. Each high-pressure tank 1 constitutes a part of the fuel cell system, and is configured to be able to supply fuel gas to the fuel cell 104 through the gas supply line 102. The fuel gas stored in the high-pressure tank 1 is a combustible high-pressure gas, for example, compressed natural gas or hydrogen gas. Note that the high-pressure tank 1 can be applied not only to fuel cell vehicles but also to vehicles such as electric vehicles and hybrid vehicles, as well as various moving bodies (for example, ships, airplanes, robots, etc.) and stationary types.

FIG. 2 is a cross-sectional view showing the main part of the high-pressure tank 1.
The high-pressure tank 1 has a tank body 2 and a base 3, and a valve assembly 4 is screwed to the base 3. The tank body 2 has a sealed cylindrical shape as a whole, and the inside thereof constitutes a storage space 6 for storing fuel gas at a pressure higher than normal pressure (that is, high pressure). For example, 35 MPa or 70 MPa hydrogen gas or 20 MPa compressed natural gas is stored in the storage space 6. Below, hydrogen gas is demonstrated to an example as high pressure gas which the high pressure tank 1 stores.

  The tank body 2 has, for example, a two-layer structure, and the two layers are an inner resin liner 10 having gas barrier properties and a CFRP layer 12 positioned on the outer peripheral side of the resin liner 10.

  The resin liner 10 (liner layer) is a part that can be referred to as an inner shell or an inner container of the high-pressure tank 1. The material of the resin liner 10 is not particularly limited, and examples thereof include a polyethylene resin, a polypropylene resin, and other hard resins. Further, these resins may be combined in two or more layers to constitute the resin liner 10 as a laminate composed of a plurality of layers. The resin liner 10 has a return portion 11. The return portion 11 is formed at one end portion or both end portions in the longitudinal direction of the tank body 2, and is folded back inside the tank body 2 so as to be separated from the CFRP layer 12. The return portion 11 is formed by continuously connecting the curved portion 16 and the cylindrical portion 17, and the curved portion 16 is continuously connected to the cylindrical body portion 18 that constitutes most of the resin liner 10 via the folded portion 19. Yes. The liner layer is not limited to the resin liner 10 and may be made of a metal such as aluminum.

  The CFRP layer 12 is a part that can be referred to as an outer shell, a shell, or an outer container of the high-pressure tank 1. The CFRP layer 12 is an FRP layer formed by reinforcing a matrix resin (plastic) with carbon fibers. Examples of the matrix resin include an epoxy resin, a modified epoxy resin, and an unsaturated polyester resin. For example, the CRPR layer 12 is formed by, for example, winding a carbon fiber impregnated with a thermosetting epoxy resin around the resin liner 10 by, for example, a filament winding method, and curing the epoxy resin by heating. The CFRP layer 12 covers the outer surface of the resin liner 10. A part of the CFRP layer 12 is also in contact with the outer peripheral surface of the base 3 and the surface of a GFRP layer 90 described later.

  The base 3 is made of a metal such as stainless steel, and is preferably made of aluminum or an aluminum alloy. The nozzle | cap | die 3 is located in the one end part or both ends of the longitudinal direction of the tank main body 2, and is integrally molded with the tank main body 2 by insert molding, for example. The base 3 includes an opening 30 having an axial center on the axis YY of the tank body 2. The opening 30 communicates the inside and outside of the tank body 2, and the valve assembly 4 is detachably attached to the inside of the opening 30. For example, the valve assembly 4 and an external gas supply line 102 are connected to supply and discharge hydrogen gas to and from the storage space 6.

  A female thread 31 that is screwed into the valve assembly 4 is formed on the inner peripheral surface of the opening 30, and a seal surface 32 is formed closer to the storage space 6 than the female thread 31. The seal surface 32 has, for example, a constant inner diameter, and is axially sealed between the valve assembly 4 and the seal members 70 and 71. The seal surface 32 is connected to the female screw 31 through the reverse tapered surface 35. The cylindrical seal portion 33 having the seal surface 32 on the inner peripheral surface is continuous with the flange portion 34 having the female screw 31 on the inner peripheral surface. Further, the outer peripheral surface of the seal portion 33 is in surface contact with the inner peripheral surface of the cylindrical portion 16.

  The seat portion 36 is continuous with the flange portion 34 and extends out of the tank body 2. The seat portion 36 includes a seat surface 37 on which the valve assembly 4 is seated, and a cylindrical inner wall surface 38 that is connected to the seat surface 37 at a right angle. The seat surface 37 is one end surface of the base 3 in the direction of the axis YY, and is formed in an annular shape. In addition, the other end surface 39 in the axis YY direction of the base 3 is located in the storage space 6 and is similarly formed in an annular shape.

  Next, the structure around the collar portion 34 of the base 3 and the GFRP layer 90 will be described with reference to FIG.

  The flange portion 34 is an annular portion centered on the axis YY, and extends to the outside in the radial direction from the seal portion 33. The collar portion 34 is disposed so as to be sandwiched between the return portion 11 and the CFRP layer 12. More specifically, the collar portion 34 is located in a space defined by the curved portion 17 of the return portion 11 and the CFRP layer 12 and is in surface contact with the curved portion 17 and the CFRP layer 12 in the axis YY direction. It is sandwiched between states. And the collar part 34 has the front-end | tip part 34a from which the front-end | tip reaches the folding | turning site | part 19, and it is formed so that the thickness of an axis line YY may become small from the base end part 34b to the front-end | tip part 34a. That is, the distal end portion 34a of the flange portion 34 is formed thinner than the proximal end portion 34b on the radially inner side.

  The tip 34a has an annular step 34c for providing the GFRP layer 90 on the surface on the CFRP layer 12 side. The step 34c is formed radially inward from the distal end of the flange 34, but does not reach the proximal end 34b. For this reason, the length of the stepped portion 34c in the radial direction is, for example, about 2L / 3, where L is the length from the distal end of the flange portion 34 to the proximal end portion 34b. By doing so, the GFRP layer 90 is provided only at the tip 34a. In order to provide the GFRP layer 90 on the stepped portion 34, the GFRP layer 90 that has been molded in advance may be simply fitted into the stepped portion 34, or may be bonded after fitting. In another embodiment, the CFRP layer 90 may be provided in a recess formed in the tip 34a instead of the step 34c.

  As shown in FIGS. 3 and 4, the GFRP layer 90 is a ring-shaped member centered on the axis YY. The GFRP layer 90 has an opening 91 at the axial center, and the opening 91 is formed in a size that allows the seating portion 36 of the base 3 to be inserted, and is stepped so as to be sandwiched between the flange portion 34 and the CFRP layer 12. It is attached to the part 34c. The GFRP layer 90 is formed so that the portion located at the distal end portion 34a is thicker than the portion located at the proximal end portion 34b. The thickness of the GFRP layer 90 corresponds to the depth of the step portion 34c, and the outer surface 92 is flush with the outer surface of the outer surface 10a of the resin liner 10 and the base end portion 34b of the flange portion 34. ing. For this reason, since the CFRP layer 12 is located on the outer surface 10a and the outer surface of the base end portion 34b of the flange portion 34 without a step, the strength of the CFRP layer 12 is appropriately maintained in this portion.

  The GFRP layer 90 is an FRP layer formed by reinforcing a matrix resin (plastic) with glass fibers. Examples of the matrix resin include an epoxy resin, a modified epoxy resin, and an unsaturated polyester resin. Here, the same thermosetting epoxy resin as the CFRP layer 12 is used. The GFRP layer 90 has an aspect of a laminated plate in which a plurality of layers are laminated. Preferably, the GFRP layer 90 is different from each other in the form of lamination, and more preferably is formed by quasi-isotropic lamination. For example, the GFRP layer 90 may be a quasi-isotropic laminate that is symmetrically laminated in 45 °, 90 °, −45 °, and 0 ° directions. By using such a quasi-isotropic laminate, the elastic characteristics are the same in all directions of the GFRP layer 90, which is suitable for stress relaxation.

  The GFRP layer 90 can be manufactured by various methods. For example, when the braiding method is used, the GFRP layer 90 as a laminate can be manufactured by molding from a GFRP prepreg using a braiding machine. Further, when the hand layup method is used, the GFRP layer 90 as a laminate can be manufactured by hand laying up the GFRP in the manufacturing mold 200 shown in FIG. 5 and molding it in a curing furnace. it can. The manufactured GFRP layer 90 is attached to the stepped portion 34c, and in this attached state, the CFRP layer 12 is formed outside by the filament winding method. As described above, when there is no GFRP layer 12, the GFRP layer 12 is provided on the outer peripheral surface portion (surface of the flange 34) of the base 3 with which the CFRP layer 12 originally contacts.

  As described above, according to the high-pressure tank 1 of the present embodiment, the GFRP layer 90 is interposed at the contact portion between the flange portion 34 and the CFRP layer 12. Thereby, the stress concentration can be relaxed by the GFRP layer 90 in the portion of the CFRP layer 12 where the stress concentration occurs. In particular, the portion where the stress concentration occurs most (the portion where the CFRP layer 12 faces the tip 34a) is thicker than the other portions of the GFRP layer 90, so the GFRP layer 90 is reduced in weight, The stress relaxation effect can be enhanced. In addition, since the GFRP layer 90 is used as the intervening layer, the pressure resistance and fatigue strength can be improved as compared with those made of rubber, and a stress relaxation effect can be ensured over a long period of time. Further, the vehicle 100 can contribute to improving the reliability of the vehicle 100 due to the high strength and long life of the high-pressure tank 1.

  In another embodiment, the GFRP layer 90 may be provided not from a part of the region of the collar part 34 but from, for example, the distal end part 34a to the base end part 34b of the collar part 34. Further, the GFRP layer 90 may be interposed in a region other than the flange portion 34 and in a contact portion between the CFRP layer 12 and the outer peripheral surface of the base 3.

It is a figure which shows the fuel cell vehicle carrying the pressure vessel which concerns on embodiment. It is sectional drawing which shows the pressure vessel which concerns on embodiment. It is sectional drawing which expands and shows the principal part of FIG. It is a perspective view of the GFRP layer concerning an embodiment. It is a figure which shows the method of manufacturing the GFRP layer which concerns on embodiment by the hand layup method, (a) is a perspective view of the type | mold for manufacture, (b) is the state which hand-laid up GFRP to the type | mold. It is a perspective view shown.

Explanation of symbols

  1: high pressure tank (pressure vessel), 2: tank body, 3: base, 10: resin liner, 10a: outer surface, 12: CFRP layer, 34: collar, 34a: distal end, 34b: proximal end, 34c : Stepped portion, 90: GFRP layer, 92: Outer surface, YY: Axis

Claims (9)

In a pressure vessel having a base and a CFRP layer in contact with the outer peripheral surface of the base,
A pressure vessel in which a ring-shaped GFRP layer is interposed in at least a part of a contact portion between the base and the CFRP layer.   The pressure vessel according to claim 1, wherein the GFRP layer is formed by quasi-isotropic lamination. A liner layer coated on the outer periphery of the CFRP layer;
The base has a collar portion disposed so as to be sandwiched between the CFRP layer and the liner layer,
The pressure vessel according to claim 1 or 2, wherein the GFRP layer is provided so as to be sandwiched between the flange portion and the CFRP layer.   The pressure vessel according to claim 3, wherein the GFRP layer is thicker at a portion located on the distal end side of the collar than on a portion located on the proximal end side thereof.   The pressure vessel according to claim 4, wherein a tip portion of the flange portion is formed thinner than a base end portion.   The pressure vessel according to any one of claims 3 to 5, wherein a concave portion or a step portion for providing the GFRP layer is formed at a distal end portion of the flange portion.   The outer surface of the GFRP layer is flush with the outer surface of the liner layer in a state where the GFRP layer is provided in the recess or step. The pressure vessel according to claim 6.   The outer surface of the GFRP layer is flush with the outer surface of the base end portion of the flange portion in a state where the GFRP layer is provided in the recess or step. The pressure vessel according to claim 6 or 7.   The pressure vessel according to any one of claims 1 to 8, wherein the GFRP layer is formed by a braiding method or a hand layup method.

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