JPH01290412A - Blow molding process of hollow formed item integrally molded with insert part - Google Patents

Abstract

PURPOSE:To obtain the blow molding process of a hollow formed item, the forming of which is easy, by a method wherein a preformed hollow insert part is attached to the blow-off part of an air blowing device and then, after the extrusion of a parison, molds are clamped. CONSTITUTION:Between molds 12 and 13, the blow-off port 9a and the return port 9b, to which a hollow filler neck 11 and a filler tube 14 are respectively attached, of an air blowing device 8 is faced and, after that, thermally melted thermoplastic resin is extruded from a mold gap A between a core 4 and a die 5 by the predetermined length so as to form a parison 6. After that, under the mold clamping state developed by putting the molds 12 and 13 close to each other, air is sent from the filler neck 11, resulting in expanding the parison 6 so as to bring it in close contact with the inner surface of the molds 12 and 13. Further, by returning the air from the filler tube 14, the interior of the molds 12 and 13 is cooled down. Finally, a product, in which the filler neck 11 and the filler tube 14 are insert-molded to a hollow formed item main body 15 produced by forming the parison 6, is obtained by opening the molds 12 and 13. As a result, the wall thickness is stabilized and the forming can be done easily.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a blow molding method for a hollow molded product such as a resin fuel tank, in which an insert part, particularly a hollow insert part, is integrally molded.

2. Description of the Related Art For example, when manufacturing a hollow molded product such as a resin fuel tank, a method of integrally molding an insert part to be installed in the tank is sometimes adopted.

An example of this molding method will be described using a baffle plate as an insert component.

The baffle plate is used to improve the mechanical strength of the product and stabilize the capacity of the molded product, as well as to partition the interior space to prevent abnormal noises caused by movement of fuel and the like while the vehicle is running.

Conventionally, the blow molding method for resin hollow molded products with a baffle plate integrally molded inside was made using polyethylene. Polypropylene, polycarbonate.

A thermoplastic resin such as vinyl chloride resin or ABS resin is heated and melted, and as shown in FIG. 7, this is extruded through the mold gap A between the core 4 and die 5 of a blow molding machine to form a parison 6 of a predetermined length. 5. This parison 6 is placed in a molding mold 1 in which one molding mold 2 is provided with a jetty part 2a as shown in FIG.
．． After clamping the mold from the left and right as shown in Figure 2, the parison 6
The parison 6 is expanded by sending air from a blow bottle into the inside of the mold 1.2, and the parison 6 is brought into close contact with the inner surface of the mold 1.2.
After cooling, the mold 1.2 was opened and the hollow molded product 3 (fuel tank body) was taken out (see Japanese Patent Laid-Open No. 55-20157).

In this way, a part of the parison 6 is pressed against the outer peripheral surface of the jetty portion 2a, and a baffle plate 3a is formed in the internal space B.

In addition, 7 in Figure 8 is the molding die! , 2 shows the cooling holes provided in FIG.

Problems to be Solved by the Invention However, in such a conventional blow molding method, the baffle plate 3a is attached to the same parison 6 as the hollow molded product 3.
Since the parison 6 is molded from the baffle plate 3a, the elongation rate of the parison 6 in the baffle plate 3a portion is much larger than that in other parts, resulting in unstable wall thickness after molding, and there is a problem in that it is difficult to set the molding conditions. Ta.

Furthermore, in cases where a plate thickness different from that of the other parts of the baffle plate 3a is required, it is extremely difficult to set the molding conditions, and the total internal capacity of the hollow molded product 3 is also reduced. .

Furthermore, in view of the external color, a recess d4 was formed in the baffle plate 3a portion, and depending on the molding conditions, wrinkles were generated on the outer surface, which could impair the aesthetic appearance.

Therefore, the present invention provides a blow molding method for a hollow molded product integrally molded with an insert part, which is easy to mold, has little influence on appearance quality, and can be manufactured efficiently.

Means for solving the problem In the blow molding method in which a hollow insert part is integrally molded with the hollow molded product body, a pre-formed hollow insert part is attached to the blowing part of an air blowing device and the parison is extruded. By clamping the molding die, the insert part is integrated with the parison, and air is blown into the parison through the insert part.

The insert part is effectively used to blow air into the parison forming the main body of the molded product.

Example Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the preparation stage for molding according to an embodiment of the present invention, in which molding molds 12 and 13 are placed facing each other below the head H of a blow molding machine consisting of a core 4 and a die 5. A blowout port 9a and a return port 9b serving as a blowout portion of the air blowing device 8 are provided between the molding molds 12 and 13. The air outlet 9a is connected to the clamped molding die 12.13.
This is for blowing air into the parison 6 inside.
On the other hand, the return port 9b circulates the air blown from the air outlet 9a into the inside of the molded parison 6.
used for cooling.

A filler neck 11 and a filler tube 14 as hollow insert parts integrated by a bracket IO are attached to the air outlet 9a and return port 9b configured in this way, respectively. The base part of the parison 6 can be molded with it inserted into the parison 6.

In addition, the filler neck above! 1 and the filler tube 14 are molded in advance from thermoplastic resin or the like.

Further, although in this embodiment they are integrated by the bracket IO, they may be directly formed integrally without using the bracket IO, or they may be molded separately.

Next, the molding process will be explained.

First, a heated and melted thermoplastic resin is extruded into a predetermined length from a mold gap A formed between a core 4 and a die 5 to form a parison 6 (see FIG. 1.3).

Next, the molding die 12.13 is brought closer in the direction of the arrow in FIGS. 1 and 3, and the pinch portion 12a of the molding die 12.13,
In the mold clamping state where the parison 6 is held between the filler neck 11 and the filler dupe! 4 is integrated with the parison 6, and air is fed from the air blowing device 8 through the filler neck 11.

Then, as shown in FIG.
2. Closely adheres to the inner surface of 13. At this time, the return port 9b to which the filler tube 14 is attached is closed by a valve (not shown), or is configured to send air together with the air outlet 9 so that the air sent from the filler neck 11 does not return. It is.

Then, by opening the return port 9b, etc., the air sent from the air blowing device 8 via the filler neck 11 is returned from the filler tube 14 to the mold 12.
．． After cooling the inside of the mold 13, when the molding die 12.13 is opened, the filler neck 11 and the filler tube 14 are inserted into the hollow molded product body 15 (fuel tank body) formed by the parison 6, as shown in FIG. The result is a product with the insert inserted.

Next, the air blowing port 9a and the return port 9 of the air blowing device 8 are opened.
The filler neck 11 and the filler tube 4 are separated from b, and the product is carried out by a take-out machine T which holds the upper part of the parison 6 with a pair of arms, and the next molding is carried out.

Therefore, filler neck 1! and filler dupe 1
Since the molded article 4 can be molded separately from the molded article body 15, there is no possibility that wrinkles or the like will occur on the outside of the molded article body 15, resulting in a deterioration in quality. Also,
Filler neck 1! However, the parison 6 is molded into the mold 12.1.
Since the filler neck 11 functions as a blow pin for inflating the filler tube 14 within the parison 6, there is no need for a blow pin. , molding can be completed while inserting into parison 6,
There is no need for the conventional process of extracting the blow pin.

Next, FIG. 5 shows the preparation stage for molding of a second embodiment of the present invention, in which a return pipe 16 and a suction pipe 17 integrated by a bracket 10 are used as insert parts, and the above-mentioned A cylindrical swirl tank 18 is integrally attached to the tip portions of a return pipe 16 and a suction pipe 17.

In this embodiment, the return pipe I6 blows air, and the suction pipe 17 has the function of controlling the return of air during cooling of the molding mold 12, 13 and supporting the swirl tank 18.

Therefore, it is possible to further reduce the number of molding steps and facilitate molding.

Note that the other configurations and molding steps are the same as in the previous embodiment, so the same parts are given the same reference numerals and explanations will be omitted.

Next, FIG. 6 shows the preparation stage for molding of the third embodiment of the present invention, in which a return tube 19, etc. is used as an insert part, and a baffle plate 20 is integrally attached to this return tube 19, etc. It is Tashino.

This embodiment is also advantageous in that the return tube 19 and the like can be effectively used for blowing air as in the previous embodiment, and can also function as a support member for the baffle plate 20, reducing the number of molding steps and facilitating molding. It is possible to aim for It should be noted that the other configurations and molding steps in this embodiment are the same as those in the first embodiment, so the same parts are denoted by the same reference numerals and the explanation thereof will be omitted.

Note that this invention is not limited to the above embodiments,
Other tubing or brackets etc. can be integrated into the insert part. Furthermore, hollow molded products are not limited to fuel tanks.

As explained in detail, according to the present invention, the wall thickness of the hollow molded product body is stabilized and molding is easier compared to the conventional molding method in which insert parts are molded from a part of the parison. There is an effect.

In addition, since the insert parts are molded separately in advance, their wall thickness can be set arbitrarily regardless of the thickness of the outer wall of the hollow molded product, and the volume of the insert parts is not taken up as much as in the past. This has the effect of increasing the internal capacity of the hollow molded product body.

Furthermore, since grooves and wrinkles do not appear on the outer surface, it is possible to manufacture products with good appearance quality.

Since the insert part is attached to the blowing part of the air blowing device, the insert part functions as a blow pin that expands the parison with air and brings it into close contact with the inner surface of the molding mold. Since it is integrated with the parison, molding can be completed while it is inserted into the parison, and there is no need for the process of extracting the blow pin as in the past, which has the effect of reducing the number of molding processes.

[Brief explanation of the drawing]

1 to 6 show embodiments of this invention, and the first
The figure is a perspective view showing the preparation stage for molding of the first embodiment, Figure 2 is a perspective view of the completed molding state, Figures 3.4 are sectional views showing each molding situation, and Figure 5 is the molding of the second embodiment. FIG. 6 is a perspective view showing the preparation stage of molding in the third embodiment; FIGS. 7.8 are a perspective view showing the molding preparation stage of the prior art and a sectional view showing the state of completion of mold clamping, respectively. It is. 6... Parison, 8... Air blowing device, 9a...
・Blowout part, 11... Filler neck (insert part), 12.13... Molding mold, 14... Filler tube (insert part), 16... Return pipe (
insert parts), 17... suction pipe (insert parts). 2 people Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] (1) In the blow molding method in which a hollow insert part is integrally molded with the main body of the hollow molded product, the pre-formed hollow insert part is attached to the blowing part of an air blowing device, and the parison is extruded and inserted into the molding mold. A blow molding method for a hollow molded product integrally molded with an insert part, characterized in that the above-mentioned insert part is integrated with the parison by mold-clamping, and air is blown into the parison through the insert part.