JPS5839704B2 - Container manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an automobile fuel tank, and more particularly to a method for manufacturing an automobile fuel tank made of olefin resin.

Conventionally, fuel tanks for automobiles are usually constructed into a container shape by joining together a plurality of partial elements drawn from steel plates.

A partition plate is attached to the inside of the tank to prevent vibrations of, for example, gasoline stored inside.

The inner walls of the casing and tank are coated with paint to prevent gasoline from seeping through, for example.

In this way, it is advantageous to install the partition plates and paint the interior before joining the plurality of partial elements as described above. A method of manufacturing a tank is advantageous which includes a step of joining to form a container.

The fuel tank as described above is a hollow body that is continuous throughout almost the entire surface.

When forming such a hollow body by molding an olefin resin, blow molding may be used.

However, since blow molding is a method of blowing air into a tube sandwiched between molds to form a hollow body, it is necessary to install partition plates to prevent undulations and to prevent seepage during the manufacturing process. It is impossible to apply paint for the purpose.

As described above, blow molding is advantageous because it allows the container to be obtained in one piece without joints, but it also has the problems described above.

Furthermore, there is also the problem that it is difficult to seal the air inlet.

On the other hand, in order to enable the installation and painting of partition plates,
If each subelement were molded separately and then joined later, problems with the strength and fluid tightness of the joints would be encountered.

Therefore, the main object of the present invention is to provide a method for manufacturing, by joining, an automobile fuel tank in which the entire bottom surface is continuous and a partition plate is formed rising from the inner wall.

Another object of the present invention is to provide a method for manufacturing a fuel tank for an automobile, which has excellent joint strength and liquid tightness.

Other objects and features of the present invention will become more apparent from the detailed description given below with reference to the drawings.

FIG. 1 is a 0-dimensional view for explaining an embodiment of the method of the present invention.

Automotive fuel tanks are made of polypropylene, for example.
The right partial element 1 and the left partial element 2 are joined together to be integrated.

A partition plate 3 for preventing wave motion is appropriately arranged between the image portion elements 1 and 2.

The partition plates 3 protrude non-orthogonally to the wall surface to which they are attached, and are arranged parallel to each other.

This partition plate 3 may be formed by integral molding with the partial element main body side, or may be molded separately and then thermally welded.

For example, when the partition plate 3 is integrally molded with the main body of the partial element, since the partial element 1゜2 is in the shape of a container with an opening on one side, the male mold that defines the inner surface is related to the partition plate 3. A shaped void is formed.

When pulling out the male mold after injection of the molding material, the partition plate 3
Since this protrudes non-orthogonally to the mounting surface, the molding is performed while making use of the elasticity of the molding material to some extent to cause the molded product to warp.

When the molding material is, for example, polypropylene, it is preferable to pull out the male mold when it loses its fluidity during the curing process, rather than pulling it out when it has completely cooled and hardened after injection.

The image portion elements 1 and 2 have a container shape with an opening on one side, and the edges of each opening have the same shape so that they can be joined to each other.

The outer edge of the opening edge is chamfered, and when the image portion elements 1 and 2 are brought together, a groove 4 having, for example, a triangular cross section is formed there.

The groove 4 is formed over the entire joint of the image part elements 1, 2.

Further, although not shown, at least one of the partial elements 1 and 2 is formed in advance with a shaped portion for connecting a pipe for refueling and a pipe for supplying fuel to the engine section, respectively. .

Before joining the image portion elements 1 and 2 as described above, processing is performed to prevent penetration of gasoline or the like.

This processing is carried out, for example, by painting the inner wall with an anti-bleeding paint or by pasting an anti-bleeding film on the inner wall.

Such processing can be carried out easily through the opening of the picture element 1.2.

Next, after the image portion elements 1 and 2 are prepared as described above, the image portion elements 1 and 2 are joined to each other.

For this mutual bonding, a mold 5 is placed along the bonded portion as shown in FIG.

The mold 5 closes the opening of the groove 4 to form a closed space for resin injection.

This closed space forms a series of passages around the entire circumference of the joint.

The mold 5 is provided with resin passages 6 at appropriate locations that communicate with the closed space, and the resin injected from the injection nozzle 7 passes through the resin passage 6 and is defined by the groove 4 and the mold 5. Fill a closed space.

The resin injected from the nozzle 7 is selected to be the same olefinic resin as the image part elements 1 and 2, and since in this embodiment the image parts 1 and 2 are composed of polypropylene, the injected resin is also polypropylene.

Similarly, if the image portion elements 1, 2 are, for example, polyethylene, the injection resin is polyethylene.

The heating temperature of the polypropylene supplied from the nozzle 7 is preferably selected to be higher than that used in normal injection molding.

In this way, the resin injected from the nozzle 7 flows into and fills the closed space defined by the groove 4 and the mold 5, but at this time, the injected resin and the constituent resins of the image portion elements 1 and 2 are mixed together. Since they are the same, they have excellent compatibility, and since the old injection resin is relatively high temperature, the resin surface that comes into contact with this resin becomes hot and activated, so the image part elements 1 and 2 and the injection resin are closely bonded. do.

That is, image portion elements 1, 2 . t, - and the injection resin are:
When the resin hardens, each interface completely disappears,
It exhibits the same properties as the molded product inside.

FIGS. 2 and 3 are cross-sectional views for explaining other practical aspects of the method of the present invention.

Note that illustration of the partition plate is omitted here.

Referring to FIG. 2, the fuel tank is integrated by joining an upper part element 11 and a lower part element 12.

The upper part element 11 has a conventional container shape. Lower part element 1
2 includes a wall portion 13 projecting outward at the edge of the opening, and a wall portion 14 rising upward from the edge of the wall portion 13.

Therefore, when the image part elements 11 and 12 are combined,
A groove 15 having a U-shaped cross section, for example, is formed by the wall portions 13 and 14 and the partial element 11 .

In mutually joining the image portion elements 11 and 12, as shown in FIG. 2, the upper mold 16 and the lower mold 1γ are placed in contact with each other.

At this time, the upper mold 16 closes the upper surface opening of the groove 15, thereby forming a closed space for resin injection.

As in the previous embodiment, resin passages 18 are provided in the mold 16.
is provided, and the resin injected from the injection nozzle 19 fills the closed space.

Next, referring to FIG.
and the lid portion element 22 are joined together to be integrated.

The lid part element 22 is fitted into and held in a stepped part formed near the upper edge of the main body part element 21.

The lid portion element 22 has a flat shape, and is notched along a ridgeline on its upper edge.

Therefore, when the image portion elements 21 and 22 are brought together as shown in FIG. 3, a groove 23 having a trapezoidal cross section, for example, is formed along the joint.

When joining the image portion elements 21 and 22 to each other, the upper mold 24 and the lower mold 17 are placed in contact with each other, as shown in FIG.

At this time, the upper mold 24 closes the upper surface opening of the groove 23, thereby forming a closed space for resin injection.

A resin passage 26 is provided in the mold 24, and the resin injected from the injection nozzle 27 fills the closed space.

As described above, according to the present invention, since the joining of each partial element is achieved by injection of the same olefin resin as the olefin resin constituting this partial element, the joining part is similar to that of an integral molded product. An automobile fuel tank with excellent strength and liquid tightness can be obtained.

In the past, during the manufacturing of fuel tanks for automobiles, the process of joining the partial elements was included, so various treatments that had to be performed on the inside of the fuel tank could be performed before the partial elements were joined. .

Therefore, the process can be performed extremely easily.

That is, this treatment includes internal coating to prevent seepage, which is common in fuel tanks, and attachment of partition plates in the casing by heat welding.

Furthermore, even if the partition plate is integrally molded, it can be easily done as long as the partial elements are in the state before being joined.

Further, the automobile fuel tank obtained according to the present invention can be made lighter in weight than that made of conventional steel plates.

Therefore, the overall weight of the car can be reduced,
It is also possible to reduce fuel consumption.

This is particularly advantageous in terms of energy savings.

[Brief explanation of drawings]

FIG. 1 is a sectional view for explaining one embodiment of the method of the present invention. FIGS. 2 and 3 are cross-sectional views for explaining other embodiments of the method of the present invention. In the figure, 1, 2, 11, 12, 21, 22 are partial elements, 3 is a partition plate, 4, 15.23 is a groove, 5.16, 17
, 24, 25 are molds, 6, 18° 26 are resin passages, ? ,
19.27 is an injection nozzle.

Claims (1)

[Scope of Claims] 1. A method for manufacturing an automobile fuel tank in which a partition plate is formed rising from an inner wall, the fuel tank having a shape divided into a plurality of parts, at least one of which has the shape of A partition plate is formed by molding a plurality of partial elements each made of the same olefin resin, and when the plurality of partial elements are arranged in the shape of the fuel tank, this joint is formed at each joint. the plurality of partial elements are arranged to form the groove, and the plurality of partial elements are arranged to form the groove; A mold that closes the opening surface of the groove is arranged, and the same heated and fluidized olefin resin as the olefin resin constituting the partial element is injected into the closed space formed there, and the injected olefin resin is heated and fluidized. A method for manufacturing a fuel tank for an automobile, including steps of curing an olefin resin and joining the plurality of partial elements to obtain the fuel tank. 2. The method for manufacturing an automobile fuel tank according to claim 1, wherein the temperature of the heated and fluidized olefin resin is selected to be higher than the temperature during normal injection molding. 3. The method of manufacturing a fuel tank for an automobile according to claim 1 or 2, wherein the partition plate is integrally molded with the at least one partial element. 4. The method of manufacturing an automobile fuel tank according to claim 1 or 2, wherein the partition plate is attached to the molded partial element before the joining step.