JP2658590B2 - Blow molding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molding method mainly used for molding a hollow container.

[0002]

2. Description of the Related Art In a synthetic resin fuel tank used for a vehicle, as shown in FIGS. 5 and 6, a tank body 1 as a hollow molded article body and a separate member extending from the tank body 1 are provided. Some include one or more filler tubes 2.

FIGS. 3 and 4 show a blow molding method used for molding the fuel tank. This blow molding method includes a tank body forming portion 3 and 4 and a pipe forming portion 5 which is a bulging portion extending from the tank body forming portion 3 and 4.
6, the preformed parison P is drawn down between the pair of right and left molds 7 and 8 having the mold 6 and the expander nozzle 9 and the blow nozzle 10 are inserted into the parison P. The parison P is sandwiched between a pair of molds 7 and 8 to completely seal the inside of the parison P while holding the shape of the parison P in a cylindrical shape with the air injected from the panda nozzle 9. The tank body 1 and the filler tube 2 are integrally formed by blowing air into the tank.

[0004]

However, in the blow molding method described above, in order to extend the filler tube 2 from the tank main body 1, the pipe forming portion is moved from the tank main body forming portion 3 to the mold closing direction of the dies 7, 8. Bulging at a steep angle. Therefore, the parison P is sandwiched between the molds 7 and 8 and
In the process of completely sealing the inside, it is pointed out that a part of the parison P is pulled by the pipe forming part 5 and the part of the parison P located between the tank body forming part 3 and the pipe forming part 5 tends to be thin. Have been.

In addition, if the fuel tank having the thin portion is used as it is, problems such as a decrease in the strength of the fuel tank and fuel permeation occur. Therefore, the fuel tank having the thin portion is defective. It is currently discarded as.

[0006]

Accordingly, in the present invention, a pair of left and right gold members having a hollow molded article main body forming portion and a swelling portion protruding from the hollow molded article main body forming portion in the mold closing direction are provided. Between the molds, the preformed parison is drawn down, an expander nozzle and a blow nozzle are inserted into the parison, and the parison is sandwiched between the pair of molds to completely seal the inside of the parison. By blowing air from the blow nozzle into the parison inside, in the blow molding method of integrally molding the hollow molded product and another member extending from the hollow molded product, the blow-down parison until the start of sandwiching by the mold of the parison. Between,
It is characterized in that a cut is made along the draw-down direction in a thin portion between the molded article main body forming portion and the bulging portion as the parison is sandwiched by the mold.

[0007]

[Action] By cutting along the drawdown direction, in the process of sandwiching the parison with the mold, the part of the parison is not pulled and the hollow molded article main body portion and the pipe portion divided by the parison notch are each formed.
It is arranged corresponding to the hollow molded article main body forming portion and the bulging portion of the mold.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with the same reference numerals being given to the same parts as those of the above-mentioned conventional example.

FIGS. 1 and 2 show a blow molding method used for molding a fuel tank comprising a tank body 1 and a single filler tube 2 as a separate member. In this blow molding method, a pair of left and right dies 7A, 8A are formed into tank body forming portions 3, 4 and pipe forming portions 5, which are bulging portions bulging from the tank body forming portions 3, 4 in the mold closing direction. 6
And Guide holes 11, 12 penetrating in the mold closing direction of the dies 7A, 8A are provided at the corners where the tank body forming portions 3, 4 and the pipe forming portions 5, 6 of the dies 7A, 8A are connected.
Is formed. From the guide hole 11 of the one mold 7A to the guide hole 12 of the other mold 8A, a linear member 13 made of a material such as a metal or glass which is not weldable to the parison P is penetrated. This linear member 13 is a parison P
Is located between the expander nozzle 9 and the blow nozzle 10 when viewed from the drawdown direction.

In order to blow-mold a fuel tank having a tank body 1 and a filler tube 2, as shown in FIG. 1, a pair of left and right dies 7A, 8A are opened and the dies 7A are opened. , 8A, draw down the preformed parison P.

Then, as shown in FIG. 2, a cut 15 is made in the thin portion between the tank body forming portions 3, 4 and the pipe forming portions 5, 6 of the parison P with the drawdown. Enter along the down direction. In parallel with this, an expander nozzle 9 is inserted into the inside of the tank body forming part side parison part P1 divided by the notch 15, and the inside of the pipe forming part side parison part P2 divided by the notch 15 is inserted. Inserts the blow nozzle 10 and keeps it in a cylindrical shape with the air injected from the expander nozzle 9.

Subsequently, when the dies 7A and 8A are closed, the guide holes 11 and 12 of the dies 7A and 8A are
The metal molds 7A and 8A that move while keeping the linear member 13 as it is along the third member 3 sandwich the parison P including the divided parison portions P1 and P2, and
While completely sealing the inside, the expander nozzle 9
Is drawn out of the divided parison part P1, and the blow nozzle 10 is sandwiched between the divided parison parts P2 by the recesses of the pipe forming parts 5, 6. In this state, blow molding air whose pressure has been adjusted by a pressure adjusting means (not shown) is blown into the parison P from the blow nozzle 10. As a result, the parison P including the divided parison portions P1 and P2 is pressed against the wall surfaces of the tank forming portions 3 and 4 and the pipe forming portions 5 and 6 of the dies 7A and 8A, and the tank body 1 and the feeder A fuel tank integrally formed with the tube 2 is formed.

Next, after the formed fuel tank is cooled and solidified, the blowing of air from the blow nozzle 10 is stopped, and then the molds 7A and 8A are opened, and the blow nozzle 10 is pulled out of the filler tube 2. At the same time, the cooled and solidified fuel tank is released from the molds 7A and 8A. Thereby, one cycle of the blow molding for molding the fuel tank including the tank body 1 and the single filler tube 2 shown in FIG. 5 is completed.

The present invention is not limited to the above-described embodiment.
It is also possible to heat the linear member 13 in which 5 is inserted to an appropriate temperature, or to make the cut 15 using light energy such as laser light instead of the linear member 13. The cut 15 can be made as long as it is between the drawdown of the parison P and the start of closing the molds 7A and 8A.

Further, pipe forming portions 5, 5 are provided on the molds 7A, 8A.
By providing a plurality of the fuel tanks 6, it is also possible to form a fuel tank having a plurality of filler tubes 2 in the tank body 1, as shown in FIG. In this case, as shown by a virtual line in FIG. 6, the plurality of filler tubes 2 may be extended in mutually opposite directions. Furthermore, cut 15 in parison P
It is also possible to put a plurality of.

[0016]

As described above, according to the present invention, the molded article main body forming portion and the bulging portion are caused by the parison being pinched by the mold before the drawdown of the parison is pinched by the die. Since a cut is made along the drawdown direction in the part that becomes thinner between the parts, in the process of sandwiching the parison with the mold and completely sealing the inside of the parison, the gap between the hollow molded product forming part of the mold and the bulging part The part of the parison that is located at is not pulled down and becomes thinner, and the hollow molded product main part divided by the parison cut and the separate members are arranged corresponding to the hollow molded product main body forming part and the bulging part of the mold It is possible to obtain a molded article having a uniform thickness having a molded article body and another member extended therefrom,
As a result, the yield of blow molding is improved, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining a blow molding method according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which the parison of the embodiment is cut.

FIG. 3 is a perspective view for explaining a conventional blow molding method.

FIG. 4 is an operation explanatory view of the conventional example.

FIG. 5 is a perspective view showing a blow-molded fuel tank.

FIG. 6 is a perspective view showing a blow-molded fuel tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tank main body (hollow molded product main body) 2 ... Filler tube (separate member) 3, 4 ... Tank main body forming part (hollow molded product main body forming part) 5, 6 ... Pipe forming part (bulging part) 7A, 8A ... Mold 13: Linear member 15: Notch P: Parison

Claims (1)

(57) [Claims] 1. A preformed parison is drawn down between a pair of left and right molds having a hollow molded article main body forming part and a bulging part bulging from the hollow molded article main body forming part in a mold closing direction. Then, an expander nozzle and a blow nozzle are inserted into the inside of the parison, the parison is sandwiched between the pair of molds, and the inside of the parison is completely sealed, and air is blown into the inside of the parison from the blow nozzle. Thus, in the blow molding method for integrally molding the hollow molded article main body and another member extending from the hollow molded article main body, the parison is sandwiched by the mold until the start of the sandwiching of the parison to be drawn down by the mold. Characterized in that a cut is made along the drawdown direction in a thin portion between the molded article main body forming portion and the bulging portion in accordance with Molding method.