JPH08117904A - Manufacture of high pressure gas container - Google Patents

Abstract

PURPOSE: To enable forming with a thin sheet stock and also to prevent buckling, in working for necking, by making a metallic die abutted with a relief on the shoulder of an opening part and reducing the surrounding wall of the opening parallelly to the center axis of an intermediate container. CONSTITUTION: In (a), an intermediate container 1 is shown which is provided with an opening 2 on the upper end and a spherical bottom 3 on the lower end. In this case, the bottom shape may also be flat. Then, in (b), a condition is shown in which necking is executed initially, where a metallic die 6 is abutted on the opening 2 and lowered along the circumferential wall 4. In this case, the metallic die 6 is abutted on the shoulder 5 at point a1 with a relief part 7 unabutting on the shoulder 5. In addition, in (c), (d), (e) where the necking process is advanced, conditions are shown in which, in order to further reduce the opening 2, the metallic die 6 is abutted on it. In this case, too, the point a2, a3, a(n) of the metallic die 6 is similarly abutted on the shoulder 5 with the relief part 7 unabutting on the shoulder 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a high-pressure gas container for storing compressed gas, and more particularly, to a lightweight high-pressure gas container and a high-pressure gas container in which wrinkles on the inner and outer peripheral surfaces of the mouth are eliminated. Regarding the method.

[0002]

2. Description of the Related Art Conventionally, a high pressure gas container for storing compressed gas is generally made of iron, but in recent years, a container made of an aluminum alloy has been proposed in response to a demand for weight reduction of the high pressure gas container.

As a conventional method for manufacturing a high pressure gas container made of an aluminum alloy, there is one as shown in FIGS. 4 and 5. 5 (a), (b), (c), and (d) are drawings showing a manufacturing process of a conventional high-pressure gas container, and FIG. 5 (a) shows an intermediate container 50. The intermediate container 50 is formed by a cold forging process in which an aluminum alloy slag is placed on a die and is pushed all at once with a punch. Then, after the cold forging process, cleaning is performed in some cases, and the end face is cut to form the opening 51 at the upper end and the spherical bottom 52 at the lower end.

Next, the necking process of the intermediate container 50 is shown in FIGS. 5 (b) (c) (d). Figure 5 (b)
(C) and (d) show drawings of three steps in which the diameter of each opening is gradually reduced. Usually, 5 to 10 types of dies are sequentially used to form a desired high-pressure gas container 55 by necking processing in 5 to 10 steps. First, as shown in FIG. 5B, the opening portion 51 is subjected to the first necking process using the mold 52. That is, the upper end of the intermediate container 50 is capped with a metal mold 53 having a constant inclination angle α and pushed in with a constant load, and the opening 51 of the intermediate container 50 is tapered at a constant inclination angle α. To do.

Next, the second necking is performed using the die 53 having the taper of the inclination angle β shown in FIG. 5 (c). In this case, the inclination angle β is larger than the inclination angle α. After performing the necking process a plurality of times as described above, the necking process is performed using the mold 54 having the taper of the inclination angle γ shown in FIG.
High-pressure gas container 5 with the opening 51 of 0 reduced in diameter to a desired shape
Get 5. FIG. 4 is a drawing showing a locus in which the opening 51 of the intermediate container 50 is gradually inclined (inclination angles α, β, ... γ). Such a conventional manufacturing method is disclosed in
No. 299738.

[0006]

However, in such an invention, as shown in FIG. 4, it is necessary to apply a load to the entire bent portion (dimension L) of the opening 51, and the inclination angle ( The load with which the die presses the opening 51 gradually increases as α, β, ... γ) increase. Therefore, the wall thickness of the container body must be thick enough to support the gradually increasing load, and when the wall thickness is thin, there is a drawback that the body buckles during necking. there were. Therefore, in the conventional manufacturing method, the base plate of the aluminum alloy before forming has to be made thicker than necessary, which causes a drawback that the formed high pressure gas container is heavy.

The present invention has been made in view of such conventional problems, and in a necking step of necking the opening of the intermediate container to reduce the diameter of the mouth of the high pressure gas container, Provided is a high-pressure gas container that can prevent buckling of the body and is light in weight with a thin body of the container, and a method of manufacturing a high-pressure gas container in which wrinkles do not occur on the inner and outer peripheral surfaces of the container. With the goal.

[0008]

In a method of manufacturing a high-pressure gas container, an aluminum alloy material is cold forged to form an intermediate container, and then a plurality of necking processes are performed on an opening and a shoulder of the intermediate container. During the necking process, the necking process should be performed on the opening so that the mold comes into contact with the shoulder of the opening with a clearance and the peripheral wall of the opening contracts in diameter parallel to the central axis of the intermediate container. It is a method of manufacturing a high-pressure gas container, which is characterized in that it is performed.

[0009]

The operation of the present invention having the above construction will be described. In the manufacturing method according to the present invention shown in FIGS. 2 and 3, since the mold comes into contact with the shoulder of the opening of the intermediate container with the relief portion, the load of the mold is small in the shoulder. receive. Therefore, as shown in FIGS. 4 and 5, in the conventional manufacturing method, since the entire bent portion (length L) of the opening is bent by the die, the load applied by the die to the entire bent portion is increased. In comparison, it can be molded with a small load. Further, in the present invention, since the peripheral wall of the opening is subjected to necking processing so as to be reduced in diameter parallel to the central axis of the intermediate container, when the mold is lowered from above,
The forming load is constant. Therefore, the bent portion of the opening is gradually inclined as in the conventional case (inclination angles α, β, ... γ).
As a result, the load of the mold on the bent portion (length L) gradually increases, and the load with which the mold presses the bent portion becomes maximum at the position of the inclination angle γ in the final process, and the container body A small load is applied to the body of the container compared to the case where an excessive load is applied to the container. Therefore, according to the manufacturing method of the present invention, since the load applied to the shoulder portion and the body portion of the intermediate container is extremely small, the thickness of the base plate before molding can be made thinner than before.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.
FIG. 2A is a sectional view showing an intermediate container 1 having an opening 2 at the upper end and a spherical bottom 3 at the lower end. The bottom shape may be the intermediate container 1 having a flat shape. FIG. 2B shows a state where the necking process is first performed, and the mold 6 contacts the opening 2 and descends along the peripheral wall 4. In this case, a
At one point, the mold 6 contacts the shoulder portion 5, and the escape portion 7 does not contact the shoulder portion 5. 2C and 2D are cross-sectional views showing a state in which the mold 6 is in contact with the opening 2 in order to further reduce the diameter thereof. In this case, similarly, a of the mold 6
Points a and a3 come into contact with the shoulder portion 5, and the escape portion 7 does not come into contact with the shoulder portion 5.

FIG. 3 is a drawing showing a locus in which the peripheral wall 4 is reduced in diameter parallel to the central axis of the intermediate container 1 by a plurality of necking processes. 8 to 1 using 8 to 12 types of molds 6
Necking is done twice. In the embodiment shown in FIG. 3, the wall thickness h0 of the body portion is 2.5 mm and the wall thickness h1 of the opening portion 2 is h1 =
As a result of subjecting the base plate made of an aluminum alloy material of 4.5 mm to necking 11 times, a high-pressure gas container having a body portion h0 of 2.5 mm and a wall thickness h2 of the opening 2 of 9.0 mm could be obtained. In the manufacturing process according to the present invention, no buckling was observed in the body of the container. The high pressure gas container had a capacity of 2.8 liters and a weight of 1.1 kg. Incidentally, when a similar high-pressure gas container having a capacity of 2.8 liters is manufactured by the conventional manufacturing method, in FIG.
By necking a base plate of 4.5 mm or more, the body portion t0 = 4.5 mm and the opening wall thickness t1 = similarly.
Although a 9.0 mm high-pressure gas container can be obtained, the base plate having a wall thickness t0 of 4.5 mm or less caused buckling of the body during necking. Therefore, according to the conventional manufacturing method, it has been found that the wall thickness t0 of the base plate when making a container having a capacity of 2.8 liters must be at least 4.5 mm or more. The weight of the 2.8-liter high-pressure gas container in this case was 1.6 kg. Further, according to the container manufacturing method of the present invention, wrinkles did not occur on the inner and outer peripheral surfaces of the opening of the high-pressure gas container after molding.

[0012]

As described above, according to the present invention, it is possible to form a base plate thinner than before in the manufacturing process for necking the opening of the high pressure gas container,
In addition, it is possible to prevent buckling and to provide a lighter high-pressure gas container, and it is possible to obtain a beautiful high-pressure gas container having no wrinkles in the opening by reasonably molding.

[Brief description of drawings]

FIG. 1 is a sectional view showing a high-pressure gas container according to the present invention.

FIG. 2 is a sectional view showing a manufacturing process of the high-pressure gas container according to the present invention.

FIG. 3 is a partial cross-sectional view showing a trajectory in which the diameter of the opening is reduced in the method of manufacturing a high pressure gas container according to the present invention.

FIG. 4 is a partial cross-sectional view showing a trajectory in which the diameter of the opening is reduced in the conventional method for manufacturing a high-pressure gas container.

FIG. 5 is a sectional view showing a manufacturing process of a conventional high pressure gas container.

[Explanation of symbols]

 1 Intermediate Container 2 Opening 4 Peripheral Wall 5 Shoulder 6 Mold 7 Relief

Claims (1)

[Claims] 1. A method of manufacturing a high-pressure gas container, wherein an aluminum alloy material is cold forged to form an intermediate container, and then a plurality of necking processes are performed on an opening and a shoulder of the intermediate container. At that time, the opening is necked so that the mold comes into contact with the shoulder of the opening with a relief and the peripheral wall of the opening is reduced in diameter parallel to the central axis of the intermediate container. And a method for manufacturing a high-pressure gas container.