JPS61171321A - Plastic tank and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain the plastic tank provided with high strength baffle plate in a simple producing process by a method in which the tank stock with dividing walls is blow molded, using a parison, and drill working is applied onto the dividing walls. CONSTITUTION:The tank wall extruding mouth 1a and the dividing wall extruding mouth 1b formed on an extruding die 1 extrude respectively the portions becoming a tank wall 4a and dividing walls 4b of a parison. At blow molding, first, as the parison with dividing walls 4b is caused to be molded, the tank stock with the tank dividing walls 6b is obtained by only carrying out normal blow molding, using this parison. By only forming through holes 6c in these dividing walls 6b, these holes provide the action of baffle plates, thereby obtaining the fuel tank 8 provided with baffle plates in very simple manufacturing process. Moreover because the peripheries of the dividing walls 6b are made integrally with the tank wall 6a, its strength is remarkably improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a plastic tank used for a vehicle fuel tank, etc., and particularly to a method for easily and reliably integrally forming a panful plate thereof. It is something.

[Prior art]

Recently, fuel tanks for vehicles have been formed using plastics from the viewpoints of cost reduction, weight reduction, etc., and a blow molding method has conventionally been used as a manufacturing method thereof. In this blow molding method, a parison made by extruding semi-molten resin into a cylindrical shape using an extrusion head is clamped by a mold that is divided into two parts, and in this state, pressurized gas is blown into the parison from a blow nozzle. This is a method in which the parison is inflated and molded along the inner surface of the mold.

By the way, conventionally, steel fuel tanks for vehicles have been formed with a buff full plate to reduce the noise of fuel vibration, but of course, this buff full plate is also necessary for plastic tanks. In the manufacturing method of plastic tanks, various methods for easily forming the baffle plate have been proposed.
There was something described in the issue. In this method, a baffle molding plate is formed protrudingly on the inner surface of the mold, and a parison is placed along the eight full molding plate by blow molding, thereby forming a baffle plate.

In this conventional publication, in the process of forming a puffful plate, the parison first comes into contact with the tip of the baffle forming plate, and is stretched toward the base of the forming plate, that is, toward the inner surface of the mold. A full plate is formed. Therefore, in this conventional method, the base of the molded buff full plate has a thin wall. On the other hand, the bending force acting on the baffle plate due to an external force such as the swinging of the fuel is greatest at the root portion, so in the plastic tank according to the conventional method described above, there is a problem that the baffle plate is weak in strength.

In addition, as a method different from the manufacturing method described in the above publication,
Conventionally, as described in Japanese Patent Application Laid-Open No. 55-79121, a pre-formed baffle plate is attached to a blow nozzle, the mold is clamped with a parison fitted thereto, and pressurized gas is then supplied. There is a blow molding method that does this. Although this conventional method can solve the above-mentioned problem of reduced strength of the baffle plate, there is a problem in that it is difficult to attach and mold a large baffle plate to a blow nozzle.

[Purpose of the invention]

The present invention has been made in view of these conventional problems, and an object of the present invention is to provide a manufacturing method capable of producing a plastic tank equipped with a highly strong panful plate through simple steps.

[Structure of the invention]

In order to achieve the above object, the present invention provides a method for manufacturing a plastic tank, in which a parison having a partition wall is first extruded, a tank material having a tank partition wall is blow-molded using this parison, and then a tank material having a tank partition wall is blow-molded. This tank partition wall is made to have holes, so that in the present invention, a tank material having a partition wall is obtained by the same molding operation as conventional blow molding, and this tank partition wall is Since it is integrated with the inner surface of the tank, its strength is extremely high, and it can function as a baffle plate just by drilling holes.

〔Example〕

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

1 to 7 are for explaining a method of manufacturing a plastic tank according to an embodiment of the present invention. First, in FIGS. 1 to 3 showing an apparatus for carrying out the method of this embodiment, Reference numeral 1 denotes an extrusion die of a parison molding apparatus for extrusion molding a parison, and this extrusion die 1 is formed with an annular tank wall extrusion opening 1a and two partition wall extrusion openings 1b crossing this, The tank wall extrusion port 1a and the partition wall extrusion port 1b are for extruding the tank wall and the partition wall of the parison, respectively, and these are in communication with each other inside the extrusion die 1. Connected to the containment chamber.

Further, below the extrusion die 1, the extrusion ports 1a and lb are provided.
Three blow nozzles 2a to 2C are arranged so as to face each of the three areas surrounded by, and each of the blow nozzles 2a to 2C is connected to a source of pressurized gas, such as compressed air. .

Also, below the extrusion die 1 are left and right molds 3a.

A mold 3 consisting of 3b is installed, and this is on the left.

The right molds 3a and 3b are movable in the left-right direction in the figure, and when they are closed, the inner surface shape is the same as the outer surface shape of the plastic tank to be manufactured. Note that 3C is a nozzle recess provided at a position facing the blow nozzles 2a to 2C of the left and right molds 3a and 3b, and 3d is a fuel supply port recess.

Next, the case where the method of this embodiment is carried out using the apparatus shown in FIGS. 1 to 3 will be explained using FIGS. 4 to 7.

(I) First, a parison is extruded with the mold 3 open.As shown in FIG. It consists of two partition walls 4b that partition into three tank chambers 5a to 5C in the direction, and when this parison 4 is extruded to a length up to the bottom surface of the mold 3, the tank chambers 5a to 5C of the parison 4 are divided into three tank chambers 5a to 5C, respectively. It will be fitted into the blow nozzles 2a to 2C.

(II) When the parison 4 is extruded to a predetermined length, the left
Close the right molds 3a and 3b. Then, the upper and lower ends 4c and 4d of the parison 4 are held between the left and right molds 3a and 3b and fused together.

(III) In this state, pressurized gas is supplied into each of the tank chambers 5a to 5c of the parison 4 from the blow nozzles 2a to 2c, and while adjusting the supply pressure, in this case, the supply pressure from the middle blow nozzle 2b is adjusted. Outer blow nozzle "la"
, supplied slightly higher than 2c. Then, the tank wall 4a of the parison 4 swells along the inner surface of the mold 3, and the partition wall 4b swells slightly outward, thereby dividing the inside of the tank wall 6a into three chambers by the tank partition wall 6b. A tank material 6 is formed (see Figure 6).
.

(IV) After the tank material 6 is cooled and solidified,
An opening for installing the Fehr gauge unit 7 is formed in the predetermined position, and the partition wall 6b is used by using the opening.
If a large number of through holes 6C are formed in and a sealing process is performed on the portions corresponding to the blow nozzles 2a to 2C, etc.,
As a result, the partition wall 6b has the function of a baffle plate.
A fuel tank 8 is obtained (see FIG. 7).

In this way, in the method of this embodiment, when performing blow molding, the parison 4 having the partition wall portion 4b is first formed, so that by simply performing normal blow molding using this parison 4, the tank partition wall 6b A tank material 6 having a baffle plate is obtained, and by simply forming a through hole 6C in this partition wall 6b, this has the function of a baffle plate, and a fuel tank 8 equipped with a baffle plate can be obtained with a very simple manufacturing process. Moreover, since the peripheral edge of the partition wall 6b is integrated with the tank wall 6a, its strength can be greatly improved.

In the above embodiment, pressurized air was supplied after the mold 3 was completely closed, but the supply of pressurized air may be started before the mold 3 is completely closed. Although the case where there are two tank partition walls 6b has been described, the method of the present invention can be easily applied to a case where there is one or more partition walls, and in this case, the parison has one or three partition walls. The shape of the extrusion port may be appropriately selected so that the extrusion port is formed as described above.

[Effects of the Invention] As described above, according to the method for manufacturing a plastic tank according to the present invention, a parison having a partition wall is formed using an extrusion die, and this is formed into a tank material having a tank partition wall by blow molding, After that, the tank partition wall is perforated, so that a plastic tank equipped with a strong panful plate can be obtained through a simple process.

[Brief explanation of the drawing]

1 to 3 show an apparatus for carrying out a method for manufacturing a plastic tank according to an embodiment of the present invention, in which FIG. 1 is a perspective view thereof, FIG. 2 is a perspective view of an extrusion die portion thereof, and FIG. Figure 3 is a sectional view of the extrusion die part, Figures 4 to 7 are diagrams for explaining the above-mentioned method, Figures 4 and 6 are process diagrams, and Figure 5 shows the parison. FIG. 7 is a sectional view showing the plastic tank. 1... Extrusion die, 2a-2C... Blow nozzle, 3
...Mold, 4...Parison, 4b...Partition wall,
5a to 5C... Tank chamber (space), 6b... Tank partition wall, 6C... Through hole, 8... Plastic tank. Patent Applicant: Mazda Motor Corporation Agent, Patent Attorney Ken Hayase - Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] (1) A parison having partition walls extending in the extrusion direction is formed by an extrusion die of a blow molding machine, and then the mold is closed and pressurized gas is introduced from a blow nozzle into each space formed by the partition walls of the parison. The parison is supplied and blow-molded into a tank material having a predetermined shape having a tank partition wall, and a through hole is formed using an opening formed at a predetermined position in the tank partition wall of the formed tank material. A method for manufacturing a plastic tank characterized by: