JPS6318489Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a plastic tank manufactured by blow molding, such as those found in automobile fuel tanks.

In recent years, most automobile fuel tanks have been made of plastic in order to reduce the weight of the vehicle. (Refer to Japanese Unexamined Patent Application Publication No. 55-20157.) For example, as shown in FIG. 1, a fuel tank includes a tank body 1 formed in a hollow rectangular parallelepiped, and a tank body 1 protruding from inside the tank body 1 for shaking fuel such as gasoline. It consists of a cross-shaped baffle plate 2 for preventing movement, an injection pipe 3 for injecting fuel into the tank body 1, etc., and these are integrally formed by blow molding.

That is, as shown in FIG. 2, the plastic fuel tank has a weir-like protrusion 6A for forming a buff-full plate 2 inside the parison 5 which has been extruded into a cylindrical shape in a softened state from a parison die (not shown). The parison 5 is held between the protruding molding molds 6, 6, and after the molds are clamped, the parison 5 is inserted through an air inlet (not shown).
When air is blown into the parison 5, the mold 6, 6
It is formed by bulging out along the inner shape of the.

However, in the case of such a plastic tank, when the buff-full plate 2 is integrally formed in the shape of a cross, the plate-shaped protrusion 6A as shown in FIG.
In order to use these in a cross-shaped combination as shown in Fig. 3, the parison 5 is built up on the upper surface of the cross portion 6a of the protrusion 6A against the blow pressure during blow molding, while the root of the cross portion 6a 6c (see Figure 4)
As shown in FIG. 4, the wall thickness is extremely thin due to narrowing from three directions, and the strength of this part is weak, resulting in breakage in some cases.

Therefore, in this invention, the length of the intersection line of the cross portion of the buttful plates is made shorter than the height of at least one buttful plate, thereby increasing the strength even though it has a cross-shaped buttful plate. Our aim is to provide highly reliable plastic tanks.

Hereinafter, embodiments of this invention will be described based on the drawings.

Figure 5 shows a plastic fuel tank of this invention. That is, in the figure, 10 is a tank body, 11 is a buffle plate, and 12 is an injection pipe.

The cross-shaped plate 11 is formed to protrude from the bottom wall portion 10A of the tank body 10 in a cross shape, and
The height (length) of the cross portion 11A is the general portion 11
It is formed lower (shorter) than the height (length) of B.

As shown in FIG.
be larger than the overhanging part 6b'' of b', and the cross part 6
The second protrusion 6A' is formed so that the length l between the upper surface a' and the upper part of the overhanging part 6a'' is shorter than the length l' of the general part 6b'.
It is formed by placing it inside the mold 6 shown in the figure and blow molding it.

When such a protrusion 6A' is used, as shown in FIG. 7, the existence of the large overhanging part 6a'' prevents the parison 5 from being pushed and expanded by the blowing pressure to the depth 6a at the base of the cross part 6a'. Therefore, the thickness of this portion is prevented from becoming extremely thin.The chain line 6a in FIG. 7 shows the case of the conventional example.

Next, FIG. 8 shows another embodiment of this invention.

This is done by changing the height of the protrusion 6A' itself to the cross section in order to shorten the protrusion distance in the same way as described above instead of changing the size of the protruding parts 6a'' and 6b'' at the base of the protrusion 6A'. This is an example in which the length of the intersection line 6a' and the general portion 6b' are changed.

That is, this is an example in which the length of the intersection line of the cross section 6a' consisting of two protrusions 6A' is formed shorter than that of the general section 6b', and the upper surface of the cross section 6a' is connected by a gentle concave curve, making it difficult to blow. The parison 5 is designed not to be torn during molding.

When these protrusions 6A' are used, not only can the same effects as in the first embodiment be obtained, but also there is an effect that the tank volume can be made equal to that of the conventional example.

It goes without saying that this invention can be applied as is to the case where the buffle plates are protruded from the upper and lower wall surfaces of the plastic tank and the protruding end surfaces of the two are fused together.

As explained above, the present invention provides a blow-molded plastic tank in which a cross-shaped baffle plate for preventing the injected liquid from swinging inside the tank body is integrally formed and protrudes from the wall surface. Because the length of the intersection line from the root connecting to the bottom wall of the cross section of the plate is shorter than the height of the other parts of the buttful plate, the parison is pulled at the cross section during blow molding. This has the effect of preventing parts from becoming extremely thin and providing uniform and sufficient strength throughout.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional plastic tank.
Figure 2 is an explanatory diagram of the blow molding method, Figure 3 is a plan view of the main parts during blow molding, and Figure 4 is A of Figure 3.
-A sectional view, Fig. 5 is a perspective view of the plastic tank of this invention, Fig. 6 is a perspective view of the protrusion of this invention, Fig. 7 is a sectional view of the main part during blow molding,
FIG. 8 is a perspective view of another embodiment of the protrusion. 10...Tank body, 11...Bullet plate, 11A...Cross part, 11B...General part.

Claims (1)

[Scope of utility model registration request] In a blow-molded plastic tank integrally formed with a cross-shaped baffle plate that prevents the injected liquid from swinging inside the tank body and protrudes inward from the wall surface, the cross portion of the buff-full plate connects to the bottom wall. A plastic tank characterized in that the length of the intersection line from the base is shorter than the height of other parts of the buttful plate.