JPH0688316B2 - Blow molding method for hollow molded products in which interior parts are integrally molded - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molding method for a hollow molded product in which interior parts such as a baffle plate are integrally molded.

2. Description of the Related Art For example, when manufacturing a hollow molded product such as a plastic fuel tank, a method of integrally molding an interior component equipped in the tank may be adopted.

An example of this molding method will be described when a baffle plate is used as an interior part.

The baffle plate defines the internal space in order to improve the mechanical strength of the product to stabilize the capacity of the molded product and to prevent abnormal noise generated by the movement of fuel or the like while the vehicle is running.

Conventionally, the blow molding method of a plastic hollow molded product in which a baffle plate is integrally molded inside is such that a thermoplastic resin such as polyethylene, polypropylene, polycarbonate, vinyl chloride resin, ABS resin is melted by heating and blown. The parison 6 having a predetermined length is extruded from the mold gap A between the core 4 and the die 5 (see FIG. 16) of the molding machine, and the parison 6 is projected onto one of the molds 2 as shown in FIG. Department
After a pair of molding dies 1 and 2 provided with 2a are clamped from the left and right in the figure, air is sent into the parison 6 to expand the parison 6 and bring it into close contact with the inner surfaces of the molding dies 1 and 2. After cooling, the molding dies 1 and 2 were opened to take out the hollow molded product 3 (see Japanese Patent Laid-Open No. 55-20157).

By doing so, a part of the parison 6 is pressed against the outer peripheral surface of the protruding portion 2a to form the baffle plate 3a in the internal space B.

In addition, FIG. 17 shows cooling holes formed in the molding dies 1 and 2.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the conventional blow molding method of the hollow molded product in which the baffle plate is integrally molded, the baffle plate is molded from the same parison as the hollow molded product. The expansion rate of the parison of the baffle plate is much larger than the expansion rates of the other parts, and the wall thickness after molding becomes unstable, making it difficult to set molding conditions.

Also, when the baffle plate is required to have a plate thickness different from that of other parts, it is extremely difficult to set the molding conditions, and the ratio of the baffle portion to the total inner volume of the hollow molded product becomes large, so that the inner volume becomes large. It also had the drawback of decreasing.

Furthermore, from the appearance surface, a groove is formed in the baffle plate portion, and wrinkles occur on the outer surface depending on the molding conditions,
There was a risk of impairing the appearance.

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

Means for Solving the Problems An interior part is hung between a pair of molding dies by a rope whose one end is fixed to a core of a blow molding machine, and a parison is pushed out to surround the interior part such as a rope and a baffle plate. , The molding die is clamped to integrally mold the interior component and the parison.

In addition, the support portion for the core of the rope is cooled or insulated to prevent heat on the core side from being transferred to the rope.

The interior parts hung on the core of the blow molding machine with a rope are stored inside by extrusion molding of the parison, and part of the outer peripheral part of the interior parts is joined to the parison by clamping the molding die. It is integrally molded.

At the same time, the rope supporting the interior parts is clamped between the walls of the parison at the pinch of the molding die and becomes integral with the hollow molding.

Further, when the support portion for the core of the rope is cooled or thermally insulated at the time of forming, it is possible to prevent heat on the core side from being transferred to the rope and adversely affecting the rope.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings by attaching the same reference numerals to the same portions as those of the conventional configuration.

First, the first embodiment is shown in FIGS.

FIG. 1 shows a molding preparatory step of the present invention. The core 4 of a blow molding machine and a floor portion 8 of the blow molding machine provided below the core 4 or a floor portion of a base plate on which the molding machine is placed are mounted. At this point, a plurality of hooks 9 are fixed, and one end of the rope 10 is fixed to each hook 9.

Then, the other end of each rope 8 is H
A baffle plate (11), which is shaped like a letter, is connected to a baffle plate (11) as an interior component, and the baffle plate (11) is supported in the air by a rope (10) from above and below.

Next, the thermoplastic resin heated and melted from the conical mold gap A formed between the core 4 and the die 5 of the blow molding machine is
The parison 6 is formed by extruding the rope 10 and the baffle plate 11 around the outer periphery thereof to a predetermined length.

Here, it is generally desirable that the baffle plate 11 and the rope 10 that supports the baffle plate 11 carry the same material as that of the parison 6 for the purpose of integrating the molding machine. It does not matter if they can be integrated.

Next, from the state shown in FIG. 1, a molding step of a hollow molding product in which a baffle plate is integrally molded inside by using a molding die
This will be described with reference to FIGS.

With the baffle plate 11 stored inside the parison 6, 2
When the split molds 12, 13 are gradually brought closer to each other in the direction of the arrow as shown in FIG. 2, the parison 6 forming the main body of the hollow molded product comes into contact with a part of the outer peripheral portion of the baffle plate 11 in order.

When the air is sent into the internal space B while the pinch portions 12a and 13a of the molding dies 12 and 13 hold the rope 10 and are in contact with each other, the state becomes as shown in FIG. 3 and the baffle plate 11 becomes a hollow molded product. The rope 10 that is integrally molded inside and supports the baffle plate 11 is completely and easily integrated at the joint portion of the parison 6.

After cooling, the molding dies 12 and 13 are opened to complete a hollow molded product 20 with high appearance quality as shown in FIG.

In the above embodiment, two ropes 8 for supporting the baffle plate 11 are provided above and below, but one rope may be provided or three or more ropes may be provided depending on the shape and size of the baffle plate to be supported. There is also.

Further, the rope that connects the baffle plate to the floor portion may be omitted as appropriate. Further, as a baffle plate, for example,
A sponge-like plate formed by foam molding a gasoline-resistant resin, or a fibrous metal (steel wool) or a fibrous gasoline-resistant resin is entangled with each other, By using a plate-shaped hardened material, it is possible to prevent the liquid level rocking noise when the vehicle turns.

Next, a second embodiment will be described with reference to FIGS.

In this embodiment, the swirling tank 21 is used as an interior part.

The swirling tank 21 is designed to ensure that the fuel can be sucked in even when the remaining amount of fuel is small when the vehicle is turning. In this embodiment, as shown in FIG. The body 21a is provided with a pair of joining ribs 21b.

That is, when the bottom of the swirl tank body 21a and the ends of the pair of joint ribs 21b are clamped from the left and right by the molding dies 12 and 13, they are joined to the parison 6 (see FIGS. 5 and 6). .

Incidentally, except that the interior part is the swirling tank 21, it is the same as the above-mentioned embodiment, and therefore the same parts are designated by the same reference numerals and the description thereof will be omitted.

Next, a third embodiment will be described with reference to FIGS.

In this embodiment, the tube unit 31 is used as an interior part.

The tube unit 31 is formed by integrating the vent tube 31a and the filler neck 31b, and a part thereof projects to the outside (see FIG. 9). Therefore, when molding, as shown in FIG. The projecting portion is located below the lower edge of the parison 6 when it is suspended from the rope 10. Then, from that state, the molds are clamped from the left and right by the molding dies 12 and 13 in the same manner as in the first embodiment described above, whereby the molding is performed.

The interior part is the tube unit 31 and is the same as the above-described first embodiment except that the hanging position of the tube unit 31 is different. Therefore, the same parts are designated by the same reference numerals and the description thereof will be omitted.

Also, the interior parts are the baffle plate 11 and the tube unit 3 described above.
Not limited to 1, it can be applied to various brackets for mounting a liquid level gauge.

Next, a fourth embodiment will be described with reference to the tenth and eleventh embodiments.

In this embodiment, the support portion for the core 4 of the rope 10 is protected from heat together with the fifth embodiment described below.

Since the core 4 is heated by its nature, the hook 9
The rope 10 may be melted and cut by the heat energy transferred to the rope.

Therefore, in order to prevent this, in this embodiment, the rope
A heat shield wall 14 of a heat insulating material is formed in the core 4 so as to surround the support portion of 10, and a passage 16 for a cooling medium 15 such as water or Freon gas is provided in the heat shield wall 14.

Therefore, according to this embodiment, the rope 10 is not cut by heat during molding, and the reliability in molding is further enhanced.

Next, a fifth embodiment will be described with reference to FIGS.

In this embodiment, in order to prevent the rope 10 from being cut by heat, an attachment piece 17 made of a heat insulating material is provided on the upper end of the rope 10 and a metal bracket 18 is integrally fixed to the upper portion of the attachment piece 17. It is a thing.

A solenoid 19 is attached to the corresponding core 4, and the bracket 18 is magnetized and suspended by the solenoid 19.

Therefore, in this embodiment, since the suspending function of the solenoid 19 and the bracket 18 and the heat insulating function of the mounting piece 17 can be exerted, there is an advantage that the rope 10 can be prevented from being cut by heat and can be automated.

The heat shield wall 14 and the passage 16 of the cooling medium 15 of the fourth embodiment are combined around the solenoid 19 of the fifth embodiment, and
It is also possible to more reliably prevent the rope 10 from being cut.

Effects of the Invention As described above, according to the present invention, the wall thickness of the molded product is stable as compared with the conventional molding method in which a part of the parison is spread to mold interior parts such as a baffle plate, This has the effect of facilitating molding.

Also, since the interior parts are pre-molded, the wall thickness can be set arbitrarily regardless of the wall thickness of the outer wall of the hollow molded product, and the volume of the interior parts does not have to be as large as before. There is an effect that the inner volume of the hollow molded product can be increased.

In addition, since no groove or wrinkle appears on the outer surface, there is an effect that a product with good appearance quality can be manufactured.

When the support portion for the rope core is cooled or insulated, the rope can be prevented from being broken by heat, so that the molding reliability can be further improved.

[Brief description of drawings]

FIGS. 1 to 4 show the first embodiment, FIG. 1 is a perspective view showing a preparatory stage for molding, and FIGS. 2 and 3 are sectional views showing a molding state, respectively.
FIG. 4 is a perspective view of the product, FIGS. 5 to 7 show the second embodiment, FIGS. 5 and 6 are sectional views showing the molding state, FIG. 7 is a perspective view of the product, and FIGS. FIG. 8 shows a third embodiment, FIG. 8 is a perspective view showing a molding state, FIG. 9 is a perspective view of a product, FIGS. 10 and 11 show a fourth embodiment, FIG. Figure 11 is number 10
The enlarged view of the XI part of the figure, FIGS. 12 and 13 show the fifth embodiment,
2 is a cross-sectional view of the main part, FIG. 13 is an enlarged view of the XIII portion of FIG. 12,
FIG. 14 is a sectional view of the main part of another embodiment, and FIG. 15 is a sectional view of FIG.
FIG. 16 is an enlarged view of the XV portion, and FIGS. 16 and 17 are a perspective view showing a molding preparation stage and a cross-sectional view showing a completed state of die clamping, respectively. 4 ... Core, 6 ... Parison, 10 ... Rope, 11 ... Baffle plate (interior parts), 12,13 ... Molding die, 20 ... Hollow molding.

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Claims (4)

[Claims] 1. A blow molding machine, wherein an interior part is hung between a pair of molding dies by a rope having one end fixed to the core, and a parison is pushed out to surround the rope and the interior part to form a molding die. A blow molding method for a hollow molded article in which an interior part is integrally formed, characterized in that the interior part and the parison are integrally formed by tightening. 2. The blow molding method for a hollow molded article integrally molded with an interior component according to claim 1, wherein the interior component is a baffle plate. 3. A blow molding method for a hollow molded article integrally molded with an interior component according to claim 1 or 2, wherein a support portion for the core of the rope is cooled. 4. A blow molding method for a hollow molded article integrally molded with an interior component according to claim 1 or 2, wherein a support portion for the core of the rope is thermally insulated.