JPH10338038A - Deformed lightweight pressure container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide light weight and sufficient pressure resistance by forming a rib, in which at least a part is constructed of highly elastic long fiber, in a thermoplastic plastic liner with an elliptic cross section shape. SOLUTION: A liner 4 made of thermoplastic plastic is shaped into a cylinder with an elliptic cross section, and a rib 5, which is formed of highly elastic long fiber and provided with a ring shape in the circumference direction, is arranged at least a part of the liner 4. By means of the rib 5, deformation of the elliptic shape due to an internal pressure, which will return the elliptic shape into a complete round shape, can be prevented. In formation of the rib 5, a recess part, 8, by which the outside face of the liner 4 is recessed while its inside face is protruded, is formed in a ring shape in the circumference direction, and the recess part, 8 is filled with highly elastic long fiber. In the outer circumference of the liner 4 in which the rib 5 is formed, a fiber reinforced resin layer 6 is formed, and then, the subject pressure container is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-weight pressure vessel having sufficient pressure resistance, and more particularly to a modified lightweight pressure vessel which can be mounted in a limited space, such as an automobile pressure vessel.

[0002]

2. Description of the Related Art In recent years, so-called non-polluting vehicles have been developed on a worldwide scale in order to prevent environmental deterioration due to vehicle exhaust gas, and natural gas vehicles are particularly attracting attention. As natural gas used for such a natural gas vehicle,
It is used in the state of compressed natural gas (CNG), and its pressure is extremely high, 3,000 to 3,500 psi. Therefore, a pressure vessel (cylinder) having pressure resistance is required, and a pressure vessel made of steel is conventionally used. Containers are used.

[0003] On the other hand, a lightweight cylinder is desirable as an automobile cylinder from the viewpoint of improving power performance, reducing collision energy, and improving fuel efficiency. Therefore, as an alternative to steel cylinders, aluminum liners reinforced with carbon fiber have been used.However, in order to achieve the ultimate weight reduction, an all-plastic liner using a plastic liner has been used. Cylinders have also been developed.

[0004]

On the other hand, for use as a cylinder for an automobile, the size and shape are important in order to mount it in a limited space in addition to weight reduction. Normal,
The shape of the cylinder is cylindrical. For example, as shown in FIG. 1, when the cylinder is mounted in a trunk room (1) of an automobile as a cylinder for an automobile, in a cylinder (2) having a perfect circular cross section, Due to the relationship with the vehicle structure, space is wasted and the size of the cylinder is limited.

On the other hand, in order to achieve such space saving,
It is conceivable to use a modified cylinder (3) having an elliptical cross section. However, when a pressure vessel using a plastic liner is used to make an elliptical shaped cylinder, 3,000p
It was not possible to achieve a commercially viable deformed cylinder with a plastic liner, since the cross-section approached a perfect circle due to pressures above si.

[0006] It is an object of the present invention to solve such a problem, that is to say that it is lightweight and has sufficient pressure resistance, and can be mounted in a limited space, resulting in a high capacity. It is to provide a lightweight pressure vessel.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the present invention is to provide a lightweight plastic having a liner made of thermoplastic plastic and a fiber-reinforced resin layer formed around the liner. A pressure vessel, wherein the cross-sectional shape of the liner is elliptical, and the liner has a rib formed at least in part by high-elasticity long fibers; is there.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
2 to 4 illustrate one embodiment of the modified lightweight pressure vessel of the present invention. 2 is a sectional view (transverse sectional view) of the pressure vessel cut in the axial direction, FIG. 3 is a longitudinal sectional view, and FIG. 4 is an enlarged view of a part of FIG.

In the present invention, a plastic liner using a thermoplastic plastic is used as the liner (4). As thermoplastics, polyolefin resins (polyethylene resin, polypropylene resin, etc.), polyamide resins (nylon 66, nylon 6)
ABS resin, polyester (polyethylene terephthalate resin, polybutylene terephthalate resin, etc.),
Polyacetal resins, polycarbonate resins and the like can be mentioned, and polyethylene resins are particularly preferable in view of cost, moldability and durability. Such a liner can be manufactured by a well-known blow molding method, rotational molding, injection molding method, or the like, and in particular, the blow molding method or the rotational molding method is preferable in view of the moldability of the hollow container.

In the present invention, such a liner (4)
Is manufactured into a cylindrical shape having an elliptical cross section. The degree of the ellipse varies depending on the required space, but preferably, the ratio of the minor axis to the major axis of the cross section is
The range of 0.5 to 0.9, preferably 0.6 to 0.8 is desirable in view of the shape of the container that can withstand high pressure well and space saving.

In the present invention, the plastic liner (4) has at least a part formed of a highly elastic long fiber, and has a circumferentially ring-shaped rib (5).
Is provided. By providing such a rib, it is possible to prevent deformation of the elliptical shape due to internal pressure that attempts to return the elliptical shape to a perfect circle. In order to effectively prevent deformation, a plurality of ribs (5) are preferably provided at equal intervals in the axial direction of the liner, and particularly, two or more ribs are preferably provided.

In forming such ribs, as shown in FIG. 4, specifically, when the plastic liner is molded by a molding method such as blow molding or rotational molding, the outer surface of the plastic liner becomes concave. It is preferable to adopt a configuration in which a concave portion (8) having a convex inner surface is formed so as to be formed in a ring shape in the circumferential direction, and the concave portion is filled with a highly elastic long fiber wound by a filament winding method. You.

The height and thickness of the ribs are preferably determined by taking into account the elastic modulus of the long fibers used and the required pressure resistance of the pressure vessel to determine the optimum ranges. Also, the thickness of the concave portion of the liner is the same as the thickness of other parts of the liner,
It is preferable to make them the same from the viewpoint of moldability of the liner. The high-elasticity long fiber used for forming the rib according to the present invention is a fiber that is conventionally used for a liner made of aluminum or a fiber-reinforced resin layer for reinforcing the outside of a plastic liner. Strength is about 400kg /
Although a fiber having a tensile strength as high as mm ² or more is used, on the other hand, a fiber having a relatively low elastic modulus is used, whereas a long fiber focused on high rigidity, that is, high elasticity is used.

Specifically, the long fiber has a tensile modulus of 40 ton / mm ² or more, preferably 50 ton / mm ^2.
It is preferable to use fibers having an on / mm ² or more and 90 ton / mm ² or less, and examples of such fibers include carbon fibers, glass fibers, aramid fibers, alumina fibers, boron fibers, and silicon carbide fibers. Although it can be selected and used, in particular, pitch-based carbon fiber using pitch as a raw material has a high tensile modulus, and thus can be suitably used.

The long fibers used for forming the ribs include:
Fiber diameter 5-10μ, tensile strength 300kg / mm ² or more,
The strain at break is preferably in the range of 0.3 to 1.5%. When filling such long fibers, it is preferable to form a fiber resin layer in the concave portion by winding a fiber impregnated with a resin by a filament winding method, rather than winding only the fiber. Examples include thermosetting resins such as epoxy resin, unsaturated polyester resin, vinyl ester resin, and phenol resin, polyamide resin, polyethylene terephthalate resin, ABS resin, polyether ketone resin, polyphenylene sulfide resin, and poly-4-methylpentene. One resin, a thermoplastic resin such as a polypropylene resin can be used, but an epoxy resin is preferable.

In the pressure vessel of the present invention, a fiber-reinforced resin layer (6) for reinforcing the strength is formed on the outer periphery of the liner having the ribs. Such a fiber-reinforced resin layer is formed by winding a reinforcing fiber sheet impregnated with a resin in advance on the outer peripheral surface of the liner, winding the reinforcing fiber sheet and then applying a resin from above, and filament filaments impregnated with the resin. A method of winding by a winding method may be mentioned, but a method of winding a resin-impregnated long fiber by a filament winding method and curing the resin to provide a fiber-reinforced resin layer is preferable.

The fibers used in the fiber reinforced resin layer include carbon fibers, glass fibers, aramid fibers, alumina fibers, boron fibers, and silicon carbide fibers.
It is preferable to use fibers having a tensile strength of 400 kg / mm ² or more. As the resin to be cured after the impregnation, a thermosetting resin such as an unsaturated polyester resin, an epoxy resin, or a vinyl ester resin is preferable.

The fiber-reinforced resin layer may be wound around the entire surface of the liner other than the base portion (7) of the liner to be a mandrel. However, it is sufficient to wind the fiber-reinforced resin layer only around the liner body. Further, the winding direction of the fiber may be any combination of the spiral direction and the polar direction, and may be arbitrarily combined. The thickness of the layer is preferably about 0.1 mm to 50 mm, preferably about 0.5 mm to 20 mm.

[0019]

Next, one embodiment of the present invention will be described in detail, but the present invention is not limited to these embodiments. (Example 1) Using a polyethylene resin, the cross-sectional shape was made to be elliptical (the major axis was 400 mm and the minor axis was 350 mm) by a blow molding method, the thickness was constant, the height was 15 mm, and the width was 10 mm. A liner having three ring-shaped recesses, which are convex on the inner surface and concave on the outer surface, were provided at equal intervals on the body of the liner.

Next, pitch-based carbon fiber (tensile elastic modulus 60
(ton / mm ² , fiber diameter: 7 μ) was impregnated with an epoxy resin, and wound by a filament winding method so as to fill the concave portion of the liner to form a rib. On the other hand, PAN-based carbon fiber (tensile strength: 600 kg / mm ² ,
A fiber impregnated with an epoxy resin having a fiber diameter of 7 μm) was wound by a filament winding method so as to form a layer having a thickness of 15 mm on the body of the liner, and the resin was cured. In the resulting container, a pressure of 3,000
When a compressed gas having psi was stored, the shape was hardly changed. (Comparative Example 1) A pressure vessel was manufactured and evaluated in the same manner as in Example 1 except that the concave portion in the liner and the rib formed by filling the pitch-based carbon fiber were not formed. The pressure vessel was deformed into a perfect circle as time passed.

[0021]

According to the present invention, it is possible to obtain a pressure vessel whose shape is not deformed by using a plastic liner having a different shape, so that the pressure vessel is lightweight and has a sufficient pressure resistance. It is possible to provide a modified lightweight pressure vessel which is very useful as a compressed natural gas cylinder for automobiles and the like, which can be mounted in a limited space.

[Brief description of the drawings]

FIG. 1 is a diagram showing a difference between a case where a pressure vessel having a true circular cross section and a pressure vessel having a modified cross section are installed in a trunk room of an automobile.

FIG. 2 is a diagram showing a cross section of one embodiment of the modified lightweight pressure vessel of the present invention.

FIG. 3 is a view showing a longitudinal section of one embodiment of the modified lightweight pressure vessel of the present invention.

FIG. 4 is an enlarged view of a part of a cross section of the modified lightweight pressure vessel of the present invention.

[Explanation of symbols]

1: automobile trunk space, 2: pressure vessel having a perfect circular cross section, 3: pressure vessel having an elliptical cross section, 4: plastic liner, 5: rib, 6: fiber reinforced resin layer, 7:
Base, 8: recess, 9: high elastic fiber

Claims (5)

[Claims] 1. A liner made of thermoplastic plastic,
A lightweight pressure vessel having a fiber-reinforced resin layer formed around the liner, wherein the liner has an elliptical cross-sectional shape, and the liner is at least partially composed of high-elasticity long fibers. A modified lightweight pressure vessel characterized by forming ribs. 2. The liner is characterized in that a concave portion having a concave outer surface and a convex inner surface is formed in a ring shape in a circumferential direction, and the concave portion is filled with a highly elastic long fiber. The modified lightweight pressure vessel according to claim 1. 3. The high elastic long fiber having a tensile modulus of 2
3. The modified lightweight pressure vessel according to claim 1, wherein a long fiber of 0 ton / mm ² or more is used. 4. The modified lightweight pressure vessel according to claim 1, wherein pitch-based carbon fiber is used as said high elasticity long fiber. 5. The modified lightweight pressure vessel according to claim 1, wherein the pressure vessel is a compressed natural gas pressure vessel.