JPH05229354A - Plastic fuel tank and its manufacture - Google Patents

Abstract

PURPOSE:To provide a plastic fuel tank having a hollow tubular baffle extending through the space between opposed wall surfaces and a method for manufacturing it. CONSTITUTION:A fuel tank has at least one hollow tubular baffle 6 integrally continued to opposed wall bodies 4, 5 in the inner part of a tank 1, both the ends being opened to the opposed wall bodies 4, 5. Baffle forming comas are provided opposite to each other in the inner parts of split molds for manufacturing a tank by blow molding, and when the split molds are closed together or after this, ring edges formed on the top ends of both the comas are closely adhered to each other or opposed to each other with a slight space, whereby the tank 1 having the hollow tubular baffle 6 extending through both the surfaces of the tank 1 can be easily manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank for automobiles and the like formed by blow molding of a thermoplastic material and a method for manufacturing the same, and more particularly to a fuel tank having a hollow cylindrical baffle between opposed wall surfaces. And a manufacturing method thereof.

[0002]

2. Description of the Related Art In the case of a plastic tank used as a fuel tank for automobiles, turning, sudden start of the automobile,
Sudden braking etc. causes the fuel in the tank to oscillate significantly, producing vibration noise, and the swaying of the fuel level causes the reading of the level gauge to fluctuate, which lowers the detection accuracy and further causes static electricity. There is an inconvenience.

In order to improve this inconvenience, for example,
Japanese Patent Application Laid-Open No. 63-258750 discloses a plastic tank integrally formed by blow molding, which has at least one pair of baffles integrally protruding inward from opposite side walls, and the tips of the opposite baffles. A plastic tank with a baffle is disclosed, characterized in that the parts are lightly fusion-bonded.

FIG. 7 is a perspective view showing an outline of the plastic tank of the above-mentioned prior invention, and shows upper and lower side walls (102) of the main body (101).
From (103), two pairs of baffles (104a) (104b) and (105a) (10
5b) is projected toward the inside of the tank.

FIG. 8 is a cross-sectional view of a pair of baffles (104a) (104b). During blow molding, the tops (106a) (106b) of a desired shape are opposed to the mold baffles at positions matching the baffles. The baffles (104a) (104b) are formed so as to project inwardly from the side walls (102) (103), and the tips of these are fused.

[0006]

The baffle described above is useful in that it can reduce the fluctuation of the fuel in the tank and increase the strength of the tank itself, but there are still some problems. There is a point.

First, since each baffle is closed by the bottom plate in the middle stage of the tank, there is a problem that foreign matters such as water, sludge and dust are likely to collect, and cleaning work for removing the foreign matter is difficult and inconvenient.

Further, if the thickness (t) of the tip end portion joining the opposed baffles is not set accurately, it causes a problem. That is, the thickness (t) with respect to the width (w) of the fused portion
Is too small, cracks may occur when an impact is applied. On the other hand, if the width (w) of the fused portion is too small with respect to the thickness (t), the fused portion easily peels off due to the impact. Becomes
If peeled off, there are disadvantages that the tank is deformed, the effect of preventing the fuel from swaying inside is reduced, and a swaying noise is generated.

It is an object of the present invention to provide a plastic fuel tank which does not retain foreign matter and is durable against impact, and a method for manufacturing the same.

[0010]

In order to achieve the above object, the present invention is configured as follows.

In a plastic fuel tank integrally formed by blow molding, inside the tank (1),
At least one hollow tubular baffle integrally connected to the opposing wall bodies (4) and (5) and having both ends open to the opposing wall body.
A plastic fuel tank having (6).

In a method of molding a hollow box-shaped plastic fuel tank by blow molding using a mold in which a pair of split molds (11) are opposed to each other, a metal mold that is aligned with the position of a baffle to be formed in the tank. Inside the mold, at least one pair of symmetrically-shaped tops (14), which have symmetrically formed edges (15) whose opposite ends project in a ring shape, are opposed to each other and a pair of split molds ( When 11) is aligned with a predetermined position, the tips of the annular edges (15) of the respective tops are brought into close contact with each other, or they are installed so as to project at a position facing each other with a slight gap, so that the blow molding A method for producing a plastic fuel tank, characterized in that a continuous baffle is formed with a tubular cross section corresponding to the outer periphery of the top (14).

In this case, it is desirable that each of the tops (14) is movably mounted in the opposite axial direction so that the facing interval of the edges (15) can be adjusted.

[0014]

The baffle (6) is formed in a hollow tubular shape with both ends open to the opposing wall body, and by eliminating the bottom plate, foreign matters such as water and dust can be prevented from accumulating inside,
Since there is no fused portion, it has durability against impact.

At the time of blow molding, an annular edge (15) is provided at the tip of the top (14) forming the baffle (6) so that the edges (15) of the pair of tops (14) are brought into close contact with each other or slightly. The continuous hollow tubular baffles (6) penetrating both sides of the tank can be easily formed by arranging them at regular intervals.

[0016]

1 is a partially cutaway perspective view of a fuel tank according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG.

The fuel tank (1) is made of a thermoplastic and has a pair of side plates (2) (3), an upper plate (wall) (4) and a lower plate (wall) (5). The upper plate (4) and the lower plate (5) are connected to each other, and two baffles (6) are provided.

Each baffle (6) is formed in a hollow tubular shape having a substantially rectangular cross section, and the upper and lower ends of the tube wall (7) are connected to the upper plate (4) and the lower plate (5). ..

FIG. 3 is a schematic cross-sectional view of an apparatus for forming the fuel tank of FIGS. 1 and 2 by blow molding.

As a molding die, a pair of left and right split dies (11) whose inner surface is formed in accordance with the shape of a fuel tank for molding should be provided as a pair, and a plastic resin melted from a die core (12) of a blow molding machine. The parison (13) is sent into the mold, and air is press-fitted into the parison (13) from the die core (12) to expand the air, thereby molding the fuel tank.

Inside each split mold (11), a pair of tops (14) are symmetrically projected at the baffle position to be formed in the fuel tank. In this embodiment, two pairs of tops are provided so as to form two sets of baffles.

The cross-sectional shape of each top (14) is matched with the inner surface shape of the hollow tubular baffle, and an edge (15) projecting annularly is formed at the outer peripheral edge of the opposing tip. The amount of protrusion of each edge (15) is at least larger than the wall thickness of the parison (13) after blow molding.

Each piece (14) has a pair of left and right split molds (11) in close contact with each other at a predetermined molding position, and the tips of the edges (15) of the pair of pieces (14) are slightly spaced apart from each other. Are attached so as to face each other, or close to each other.

In the illustrated embodiment, the frame (14) of the split mold (11)
The guide cylinders (16) are installed at the positions where the brackets are mounted, the tops (14) are slidably fitted in the guide cylinders (16), and the adjustment bolts (17) screwed to the bottom lid of the guide cylinders (16) are used. The top (14) is moved back and forth so that the distance at which the tips of the edges (15) face each other can be adjusted.

The procedure for manufacturing the fuel tank having the hollow tubular baffle shown in FIGS. 1 and 2 by using the mold having the above-described structure is as follows.

First, as shown in FIG. 3, a pair of split molds (11) are opposed to each other with a gap, and a parison (13) is sent from a die core (12) to press air into the parison (13).
Expands along the inner wall of the split mold (11) and the outer surface of the core (14). Figure 4 shows the tip of the core (14) and the core (1
FIG. 4 is a cross-sectional view showing a portion of a parison (13) formed by being recessed by 4). After the parison (13) is inflated to some extent, the pair of split molds (11) may be brought close to the position shown in FIG.

Next, while the air is being pressed in or after closing both ends of the parison (13), the pair of split molds (11) is further moved to a molding position where they are in close contact with each other.
As shown in FIG. 5, the left and right portions of the core (14) recessed in the core (14) are in close contact with each other to form an integral bottom plate (19), while the left and right cores (14) are formed on the outer peripheral surface of the core (14). The part formed along the above forms a hollow tubular baffle (18) connecting the upper and lower wall surfaces of the fuel tank.

The bottom plate (19), which is recessed into the tips of the left and right cores (14) and adheres integrally, has a baffle (18) portion when the edges (15) of the cores (14) are completely adhered. Although it is more completely separated, when the edges (15) face each other at a slight interval, the bottom plate (9) is baffled via the thin peripheral portion (20) corresponding to the facing interval of the left and right edges (15). Connected to (18).

Next, the left and right split molds (11) are opened, and the molded fuel tank is taken out. This fuel tank is shown in Figure 1.
2 is provided with hollow tubular baffles formed in the shape shown in FIG.

When the bottom plate (19) remains in the middle of each baffle via the thin peripheral portion (20), a cutter knife (21) or a punch or the like may be used as necessary as shown in FIG. Using a suitable tool, the peripheral portion (20) connecting the bottom plate (19) and the baffle wall (18) is cut off to remove the bottom plate (19) from the inside of the baffle. The peripheral edge (20) is an edge (15) of a pair of cores (14).
Since they are formed with a wall thickness that matches the facing distance, if the distance between the edges (15) is set as small as possible and the peripheral edge (20) is made thin, the cutting is extremely easy. is there.

Thus, the plastic fuel tank shown in FIGS. 1 and 2 provided with the hollow tubular baffle (6) integrally connected to the opposing wall body and having both ends open to the opposing wall body is manufactured. You can

In the above embodiment, each core (14)
Although it was pressed against the parison (13) together with the split mold (11), each core (14) was slidably attached to the split mold (11), and after closing both split molds (11), Air cylinder (not shown)
For example, the baffles (18) may be formed by pushing both cores (14) toward each other.

[0033]

【The invention's effect】

(a) The baffle that is formed integrally with the tank is a hollow tube that connects the opposing wall bodies of the tank, and the entire baffle is formed as a through hole that penetrates between the opposing wall bodies. , Foreign matter such as dust does not collect, and cleaning work becomes easy.

(B) It is possible to completely eliminate the inconvenience such as the separation of the joint portion in the conventional baffle which is formed by simply making the opposing wall bodies concave and joining them.

(C) At the time of manufacturing, it can be easily carried out by forming an annular edge at the tip of the core attached to the mold for blow molding.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a fuel tank according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a schematic cross-sectional view showing an example of an apparatus for carrying out the method for manufacturing a fuel tank of the present invention.

FIG. 4 is a cross-sectional view showing a step of forming a buffer.

FIG. 5 is a cross-sectional view showing a core and a parison at the time of buffer molding.

FIG. 6 is a cross-sectional view showing how to cut off the bottom plate of the molded buffer.

FIG. 7 is a perspective view showing a conventional fuel tank with a buffer.

FIG. 8 is a cross-sectional view showing the shape of a conventional buffer.

[Explanation of symbols]

(1) Fuel tank (2)
(3) Side plate (4) Top plate (wall) (5)
Bottom plate (wall) (6) Baffle (7)
Baffle wall (11) Split type (12)
Dycore (13) Parison (14)
Frame (15) Edge (16)
Guide tube (17) Adjustment bolt (18)
Baffle wall (19) Bottom plate (20)
Thin edge (21) Cutter knife

Claims (3)

[Claims] 1. A plastic fuel tank integrally formed by blow molding, wherein at least one hollow, which is integrally connected to an opposing wall body inside the tank and has both ends open to the opposing wall body. A plastic fuel tank having a tubular baffle. 2. In a method for molding a hollow box-shaped plastic fuel tank by blow molding using a mold in which a pair of split molds are opposed to each other, the mold is aligned with the position of a baffle to be formed in the tank. When at least one pair of symmetrically-shaped tops, each of which has a symmetrically-shaped edge with annularly protruding opposite ends, are opposed to each other and a pair of split molds are aligned in a predetermined position. , The tip of the annular edge of each piece is closely contacted or is installed so as to project at a position facing each other with a slight gap left, so that at the time of blow molding, a tubular cross section corresponding to the outer circumference of each piece is formed to be continuous. A method for manufacturing a plastic fuel tank, which comprises forming a baffle. 3. The method for manufacturing a plastic fuel tank according to claim 2, wherein each of the tops is movable in the axial direction opposite to each other so that an edge interval can be adjusted.