JPS6246374B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a synthetic resin fuel tank.

In a normal fuel tank, the fuel strainer's fuel inlet is located at the bottom of the fuel tank.
The fuel sucked out from this fuel suction port is supplied to a carburetor or a fuel injection valve. However, with such a fuel tank, if the vehicle suddenly starts, stops, or turns sharply when the fuel in the fuel tank is low, the fuel in the fuel tank becomes uneven, and as a result, fuel gets trapped around the fuel strainer's fuel inlet. This creates a problem in that fuel cannot be temporarily supplied to the carburetor or fuel injection valve. In order to solve this problem, in conventional metal fuel tanks, a pot-shaped sub-tank is fixed on the bottom wall of the fuel tank, and the fuel inlet of the fuel strainer is disposed within this sub-tank. When a sub-tank is provided in this way, even if the vehicle suddenly starts, stops, or turns suddenly, most of the fuel in the sub-tank remains in the sub-tank, making it possible to continuously supply fuel to the carburetor or fuel injection valve. Can be done. As is clear from the above-described function of the sub-tank, a sub-tank is necessary even if the fuel tank is made of synthetic resin material, but there are almost no conventional synthetic resin fuel tanks equipped with a sub-tank.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a synthetic resin fuel tank that can extremely easily mold a sub-tank having a complicated structure.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 show a completed synthetic resin fuel tank according to the present invention. Referring to FIG. 1, 1 is a synthetic resin fuel tank made of polyethylene, and 2 is a bottom wall 3 of the fuel tank 1.
A sub-tank formed above is shown, and a fuel strainer 4 is disposed within this sub-tank 2. Further, a curved fuel flow passage 5 is formed on the fuel tank bottom wall 3 around the sub-tank 2,
The fuel flow passage 5 has a fuel flow hole 6 opening into the fuel tank 1 at one end thereof, and an opening 7 opening into the subtank 2 at the other end thereof. In this way, the inside of the fuel tank 1 and the inside of the sub-tank 2 are connected to each other via the fuel flow path 5, so when the fuel in the fuel tank 1 is low and the vehicle is running steadily, the liquid level in the fuel tank 1 is The height of the liquid level in the sub-tank 2 is equal to the height of the liquid level in the sub-tank 2. On the other hand, if the vehicle makes a sudden turn, for example, the fuel in the fuel tank 1 will shift to one side within the fuel tank 1, but the fuel in the sub-tank 2 will flow out into the fuel tank 1 because the fuel flow path 5 is curved. Therefore, the fuel in the sub-tank 2 remains in the sub-tank 2.

Next, a method for manufacturing a synthetic resin fuel tank according to the present invention will be explained with reference to FIGS. 4 to 7. 4 and 5 show a mold 10 for manufacturing part A in FIG. be. On the flat part 11 of this mold 10 is a cylindrical raised part 12 for forming the sub-tank 2.
A curved raised portion 13 for forming a fuel flow passage 5 extending from the lower end of the peripheral wall of the cylindrical raised portion 12 along the periphery of the raised portion 12 is integrally formed. As shown in FIG. 6, a thin synthetic resin layer 14 made of polyethylene is formed on the mold 10 by, for example, blow molding. Note that this synthetic resin layer 14 can be molded by a molding method other than the blow molding method, such as an injection molding method, an injection molding blow molding method, or a rotational molding method. This synthetic resin layer 14 is then separated from the mold 10. Next, the head portion of the synthetic resin layer portion 14a covering the cylindrical raised portion 12 is cut off as shown in FIG. 7, thereby forming the top opening 15 of the sub-tank 2. On the other hand, an opening 1 is provided at the tip 14c of the synthetic resin layer portion 14b covering the curved raised portion 13.
6 is bored, and this hole 16 constitutes the fuel flow hole 6 of the fuel flow path 5 . Next, the synthetic resin plate 17 is welded and fixed onto the back surface of the synthetic resin layer 14 by spin welding, friction welding, ultrasonic welding, etc. so as to cover the bottom areas of the synthetic resin layer portions 14a and 14b. .

Therefore, as shown in FIG. 3, the sub-tank 2 is formed between the synthetic resin layer portion 14a and the synthetic resin plate 17, while the sub-tank 2 is formed between the synthetic resin layer portion 14b and the synthetic resin plate 1.
A fuel flow path 5 is formed between the holes 7 and 7.

As described above, according to the present invention, after molding the fuel tank, the head of the synthetic resin layer portion 14 is cut off, the opening 16 is bored in the tip end 14c of the synthetic resin layer portion 14b, and then the synthetic resin plate 17 is formed. The sub-tank can be formed using a simple process of welding and fixing. Therefore, not only is there no need for the complicated process of separately forming the sub-tank and the fuel flow passage and attaching them to the fuel tank, but there is also the advantage that the number of parts can be reduced to just one, the synthetic resin plate 17.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional perspective view of a completed synthetic resin fuel tank according to the present invention, FIG. 2 is an enlarged plan view of section A in FIG. 1, FIG. 3 is a side sectional view of FIG. 2, and FIG. The figure is a partial perspective view of the mold, Figure 5 is a plan view of the mold shown in Figure 4, Figure 6 is a perspective view showing the synthetic resin layer formed on the mold, and Figure 7 is a view from the mold. FIG. 3 is a perspective view of a separated synthetic resin layer. 1...Synthetic resin fuel tank, 2...Sub tank, 5...Fuel distribution passage, 6...Fuel distribution hole, 1
0... Mold, 12... Cylindrical raised part, 13... Curved raised part, 14... Synthetic resin layer, 17... Synthetic resin plate.

Claims (1)

[Claims] 1. A cylindrical raised part for forming a sub-tank on a mold for forming the bottom wall of a fuel tank, and a curved part for forming a fuel flow path extending from the lower end of the peripheral wall of the cylindrical raised part along the periphery of the raised part. A thin synthetic resin layer is formed on the mold to cover the cylindrical raised part and the curved raised part, and then the synthetic resin layer is separated from the mold, and then the cylindrical raised part is formed. The top opening of the sub-tank is formed by cutting off the head of the synthetic resin layer formed by the curved protrusion, and an opening is bored at the tip of the synthetic resin layer formed by the curved protuberance to form the fuel flow passage. A fuel tank made of synthetic resin, in which a fuel flow hole is formed, and then the bottom area of the synthetic resin layer formed by the cylindrical raised part and the curved raised part is covered with a synthetic resin plate fixed by welding. Production method.