KR20180060772A - Forming apparatus of plastic fuel tank and plastic fuel tank for vehicle manufactured by apparatus thereof - Google Patents

Abstract

The present invention relates to a plastic fuel tank molding apparatus and a plastic fuel tank for vehicles manufactured using the apparatus. In manufacturing the plastic fuel tank (500) through blow molding, a parison (200) is pressed only by a mold used for the blow molding so that the parison is thermally welded. On a surface of the plastic fuel tank (500) having been manufactured, a fusion line (510) made of a straight line without a lump is formed.

Description

TECHNICAL FIELD [0001] The present invention relates to a plastic fuel tank, and more particularly, to a plastic fuel tank forming apparatus and a plastic fuel tank using the same. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a plastic fuel tank for a vehicle and a plastic fuel tank for a vehicle manufactured using the apparatus, and more particularly to a plastic fuel tank using a blow molding, And a plastic fuel tank for a vehicle manufactured by using the apparatus.

2. Description of the Related Art Generally, an engine of a vehicle is a device that converts thermal energy into mechanical rotational force by rotating a crankshaft using an explosive force generated by burning fuel in a combustion chamber.

In such an engine, fuel to be burned in the combustion chamber is continuously supplied, and a fuel tank capable of storing a certain amount of fuel in the vehicle is provided for continuous supply of fuel.

The fuel tank is usually made of steel and plastic. In recent years, however, the use of plastic fuel tanks for weight reduction and fuel economy improvement is increasing.

The plastic fuel tank is largely manufactured by a melting process, an extrusion process, and a blowing process. The melting process is a process of melting a plastic material by heating it to a high temperature and melting it with a molten resin. twin sheet, and cylindrical shape. In the blowing process, the parison is injected into the mold and the high-pressure air is blown into the parison to mold the parison into the shape of the fuel tank .

The plastic baffle is placed inside the parison and then the blowing process is performed. Accordingly, as the parison and the plastic baffle are fusion-bonded to each other in the course of the blowing process, An integrally bonded plastic fuel tank is produced.

On the other hand, the blowing process is performed through two steps of primary blowing and secondary blowing.

The primary blowing is a process for imparting stretchability to the parison by improving the fluidity of the resin. The secondary blowing is a process for molding the parison to which elasticity is imparted in the shape of a fuel tank. If the blowing process is a primary blowing, If the molding is performed in one step without dividing into two stages of the secondary blowing, high pressure air acts on the parison, which is not given elasticity, so that quality problems occur in the completed fuel tank, and in some cases, In order to prevent this, there are two stages of primary blowing (pre-blowing) and secondary blowing.

The primary blowing proceeds in a state in which the mold is released, and the secondary blowing proceeds in a state in which the metal mold is joined.

On the other hand, as shown in FIG. 1, a welding line 11 is formed on the surface of the plastic fuel tank 10 that has been manufactured by blow molding. Most of the welding lines 11 are formed as a straight line 12 , And a part of the section is formed in the form of a lump portion (13) in which the straight line (12) is bundled, and the lump portion (13) is generated during the secondary blowing process in a conventional molding machine.

That is, the fusing line 11 of the plastic fuel tank 10 is formed by connecting the parisons by thermal fusion during the blow molding process. When the parison is thermally welded only by the mold during the blow molding, 11 are formed only with the straight line 12 without the aggregation portion 13. [

However, when the parison is thermally welded to the mold by using the mold used in the blow molding and the additional parts provided in the mold, the fusion line 11 of the plastic fuel tank 10 is connected to the straight line 12 by the mold, And a gathering portion 13 of additional parts is formed together.

2, the concave portion 14 and the convex portion 15 located on both sides of the concave portion 14 are formed such that the thickness of the concave portion 14 is smaller than the thickness of the concave portion 14, And the convex portion 15 is formed such that the thickness of the resin is relatively thicker than the peripheral portion.

The convex portion 15 having a large thickness is contracted at the time of cooling after the heat fusion and pulls the concave portion 14 located in the periphery while the concave portion 14 becomes thinner due to the pulling action, And a notch 14a is formed at the thinnest portion.

The fuel tank 10 is subjected to an endurance test by applying a free fall or a blow to the fuel tank 10. At this time, cracks are generated in the concave portion 14 having a thin thickness at the aggregation portion 13 and a notch 14a formed therein There is a disadvantage in that the defective rate of the product increases.

It should be understood that the foregoing description of the background art is merely for the purpose of promoting an understanding of the background of the present invention and is not to be construed as an admission that the prior art is known to those skilled in the art.

Korean Patent Publication No. 10-2010-0016339

SUMMARY OF THE INVENTION Accordingly, the present invention is conceived to solve the above-mentioned disadvantages, and it is an object of the present invention to provide a plastic fuel tank, which is formed by using a blow molding process, It is an object of the present invention to provide a plastic fuel tank molding apparatus capable of improving the durability of the fuel tank and improving the quality of the product by improving the quality of the product, and a plastic fuel tank for a vehicle manufactured using the apparatus .

In order to accomplish the above object, the present invention provides a molding apparatus for blow molding a parison made of a plastic molten resin into a shape of a plastic fuel tank, wherein a mold projection is formed in a direction toward the parison A first inner mold on one side and a second inner mold on the other side; A first outer mold which is configured to surround the first inner mold and operates separately from the first inner mold; And a second outer mold that is configured to surround the periphery of the second inner mold and operates separately from the second inner mold; Wherein the first outer mold and the second outer mold are configured to perform a merging and releasing operation; The first inner mold and the first outer mold are connected to each other while the parison is connected to the second inner mold and the second outer mold in the form of a plastic fuel tank, And is molded.

And a baffle pin configured to be capable of being inserted into or out of the parison through an opened lower end of the parison in which an air hole for primary blow molding of the parison is formed and a baffle is inserted at an upper end thereof .

The first and second outer molds may be located below the first and second outer molds to perform a closing operation and an opening operation. The PCD may be configured to close the lower end of the parison in a closing operation.

The parison extruded from the head core of the extruder is gripped and moved to the space between the first and second outer molds and the parison moved to the space between the first and second outer molds is firstly blow- And a parison robot which closes the upper end of the parison protruded to the upper side of the mold.

A first inner mold and a second inner mold which are inserted through the mold, and at the time of inserting, an end portion of the parison penetrates the parison and is positioned inside the parison, And a needle pin having an air hole formed therein for blow molding.

In the first blow molding of the parison, the baffle pins into which the baffles are inserted are inserted into the parison in a state where the first and second inner molds and the first and second outer molds are both released, And is then closed after being closed by both the reconnaissance robot and the PCD.

After completion of the primary blow molding of the parison, the first and second inner molds move toward the parison so that the mold protrusions fix the baffle; The baffle pin is moved down to the PCD position after the baffle is fixed by the mold projection; The first and second outer molds are joined together after the baffle pin is moved downward; After the first and second outer molds are assembled, the baffle pin is removed from the PCD and the PCD is closed to close the bottom of the parison, thereby maintaining the parison's airtightness. Characterized in that the parison is secondarily blow-molded in the form of a plastic fuel tank through the air supplied through the needle pin after the needle pin is inserted into the parison through the parison in the airtight state of the parison .

In addition, a parison fusing line is formed on a surface of a fuel tank manufactured using the apparatus according to the present invention, and the fusing line is formed only in a straight line without a lump portion.

According to the present invention, when the plastic fuel tank is manufactured by blow molding, the parison is pressed only by the mold used for the blow molding so that the parison is thermally welded to the surface of the plastic fuel tank, Thereby improving the durability of the plastic fuel tank which has been molded, and it is possible to prevent cracks from occurring in the fusion line during the endurance test, thereby improving the quality problem of the product , And further, the merchantability can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a prior art drawing showing a lump in a fusion line in a plastic fuel tank produced by blow molding;
2 is a sectional view taken along the line I-I in Fig. 1,
3 is a process diagram for explaining a process of molding a plastic fuel tank using the apparatus according to the present invention,
4 and 5 are views for explaining baffle pins and needle pins used in the apparatus according to the present invention.

Hereinafter, a plastic fuel tank molding apparatus according to a preferred embodiment of the present invention and a plastic fuel tank for a vehicle manufactured using the apparatus will be described with reference to the accompanying drawings.

FIG. 3 shows a plastic fuel tank using the apparatus according to the present invention and a plastic fuel tank having been manufactured.

The molding apparatus according to the present invention includes a first inner mold 110 and a second inner mold 120 on one side where the mold protrusions 111 and 121 are formed in a direction toward the parison 200, respectively. A first outer mold 130 configured to surround the periphery of the first inner mold 110 and operated separately from the first inner mold 110; And a second outer mold (140) configured to surround the periphery of the second inner mold (120) and to operate separately from the second inner mold (120); The first outer mold 130 and the second outer mold 140 are configured to perform a merging and releasing operation; The first inner mold 110 and the first outer mold 130 are connected to each other and the second inner mold 120 and the second outer mold 140 are connected to each other. The parison 200 is blow-molded in the shape of a plastic fuel tank.

The apparatus according to the present invention further includes an air hole 151 for primary blow molding of the parison 200 and a baffle 300 at the upper end thereof, A baffle pin 150 configured to be inserted or withdrawn into the inside of the baffle 200; A PCD 160 that is positioned below the first and second outer molds 130 and 140 to perform a closing operation and an opening operation and closes an opened lower end of the parison 200 in a closing operation; The parison 200 extruded from the head core 400 of the extruder is gripped and moved to the space between the first and second outer dies 130 and 140 and the parison 200 moved to the space between the first and second outer dies 130 and 140 A parison robot 170 which closes the upper end of the parison 200 protruded above the first and second outer molds 130 and 140 before the first blow molding of the parison 200 is performed. The first inner mold 130 and the second inner mold 140 are inserted through the mold and the ends of the first inner mold 130 and the second inner mold 140 are inserted into the parison 200 through the parison 200, And a needle pin 180 having an air hole 181 formed therein for secondary blow molding of the parison 200 after the blow molding is completed.

Hereinafter, the molding apparatus according to the present invention will be described in more detail through a process of manufacturing a plastic fuel tank by blow molding.

When the plastic material is melted as a molten resin by heat at a high temperature in the melting machine, the melted resin has a shape of C shape, twin sheet or cylindrical shape through the head core 400 of the extruder as shown in Fig. 3 (A) The parison 200 is extruded into a parison 200 and the extruded parison 200 is separated from the head core 400 while the upper end thereof is held by the parison robot 170.

The parison 200 held by the parison robot 170 is moved between the first and second outer dies 130 and 140 as shown in FIG. 3 (B), and the parison robot 170 is moved The upper end of the baffle pin 200 is sealed and the baffle pin 150 in which the baffle 300 is inserted through the lower end of the opened parison 200 is inserted into the inside of the parison 200, As the PCD 160 is closed after insertion, the lower end of the parison 200 is also sealed.

A protrusion 152 is formed on the upper end of the baffle pin 150 and a groove 310 is formed in the lower end of the baffle 300 to receive the protrusion 152. The baffle pin 150 has an upper end So that the baffle 300 is inserted.

After the upper and lower ends of the parison 200 are both sealed by the parison robot 170 and the PCD 160, high pressure air is introduced into the parison 200 through the air holes 151 provided in the baffle pins 150. [ A pre-blowing process is performed in which the parison 200 is injected into the inside of the parison 200, and the fluidity of the resin is improved through the primary blow molding, thereby giving the parison 200 elasticity.

The primary blow molding of the parison 200 proceeds with the first and second inner molds 110 and 120 and the first and second outer molds 130 and 140 being released as shown in FIG. 3B.

When the primary blow molding is completed, the first and second inner molds 110 and 120 move toward the parison 200 as shown in FIG. 3 (C). In this process, the first and second inner molds 110 and 120, As the projections 111 and 121 press the parison 200, the parison 200 and the baffle 300 are fused together.

When the baffle 300 is fixed by the mold protrusions 111 and 121 of the first and second inner molds 110 and 120, the baffle pin 150 is lowered (retracted) to the position of the PCD 160 as shown in FIG. After the baffle pin 150 moves, the first and second outer molds 130 and 140 are assembled together as shown in FIG. 4 (E).

When the baffle pin 150 is completely lowered to the lower side of the PCD 160 without moving down to the position of the PCD 160, the parison 200 is filled with air through the primary blowing, Air in the lower part of the parison 200 is not maintained and air inside the parison 200 falls outside the parison 200. In this case, the moldability is deteriorated at the time of secondary blow molding which will be described later.

Accordingly, when the baffle pin 150 is moved downward (retracted) after the primary blow molding of the parison 200, the parison 200 can be kept airtight by moving only to the position of the PCD 160, Accordingly, it is possible to improve the moldability of the parison 200 during the secondary blow molding by preventing the air from coming off.

Since the mold protrusions 111 and 121 provided on the first and second inner molds 110 and 120 press the baffle 300 and continue to fix the baffle 300 when the baffle pin 150 is retracted, Only the baffle pin 150 is moved downward.

4F, the baffle pins 150 are further lowered to the PCDs 160 and 160 after the baffle pins 150 are retracted to the position of the PCD 160 and then the first and second outer molds 130 and 140 are assembled. And the PCD 160 performs a closing operation to seal the lower end of the parison 200, so that the interior of the parison 200 is kept airtight continuously.

When the lower end of the parison 200 is sealed by the PCD 160 as described above, the needle pin 180 is inserted through one of the first and second inner molds 110 and 120, 180 extend through the parison 200 and reach the interior of the parison 200.

When the tip of the needle pin 180 is positioned inside the parison 200, the high-pressure air flows through the air hole 181 provided in the needle pin 180 as shown in FIG. 5 200 so that the parison 200 is subjected to secondary blow molding and the parison 200 is completed to be formed into the shape of the plastic fuel tank 500 through the secondary blowing .

After the parison 200 is completely molded into the plastic fuel tank 500 through the secondary blowing, the needle pins 180 are removed from the mold, the combined molds 110, 120, 130, 140 are again released, 4 (G), the blow molding is terminated by taking out the plastic fuel tank 500 that has been molded.

The fusing line 510 is formed on the surface of the plastic fuel tank 500 that has been manufactured using the apparatus as described above. The fusing line 510 connects the first and second outer dies 130 and 140, The fusing line 510 according to the present invention is formed as a continuous line having no clump portion as in the prior art. The fusing line 510 is formed by pressing the two outer molds 130 and 140, .

That is, the molding apparatus according to the present invention has a configuration in which the parison 200 is pressed and thermally fused with only the first and second outer molds 130 and 140, and thus the surface of the plastic fuel tank 500, The fusion splicing line 510 is formed in the fusion splicing line 510. In particular, the conventional splicing splice is not present in the fusion splicing line 510, whereby the durability of the fuel tank 500 can be greatly improved, It is possible to eliminate the phenomenon of cracks occurring in the fusing line 510 when performing the endurance test by applying the freefall or strike to the completed fuel tank 500. As a result, the quality problem of the product can be improved, There is an advantage that it can be achieved.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims It will be apparent to those of ordinary skill in the art.

110 - first inner mold 120 - second inner mold
130 - first outer mold 140 - second outer mold
150 - Baffle Pin 160 - PCD
170 - Brush with parison 180 - Needle pin
200 - Parison 300 - Baffle
400 - Head Core 500 - Plastic Fuel Tank
510 - Fused line

Claims (8)

A molding apparatus of a plastic fuel tank for blow molding a parison made of a plastic molten resin into a shape of a plastic fuel tank,
A first inner mold on one side and a second inner mold on the other side in which mold protrusions are formed in a direction toward the parison;
A first outer mold which is configured to surround the first inner mold and operates separately from the first inner mold; And
And a second outer mold configured to surround the periphery of the second inner mold and operated separately from the second inner mold;
Wherein the first outer mold and the second outer mold are configured to perform a merging and releasing operation;
The first inner mold and the first outer mold are connected to each other while the parison is connected to the second inner mold and the second outer mold in the form of a plastic fuel tank, And the plastic fuel tank is molded. The method according to claim 1,
And a baffle pin configured to be capable of being inserted into or out of the parison through an opened lower end of the parison in which an air hole for primary blow molding of the parison is formed and a baffle is inserted at an upper end thereof Characterized in that the plastic fuel tank molding apparatus. The method of claim 2,
Further comprising a PCD which is located below the first and second outer dies so as to be able to perform a closing operation and an opening operation and closes an opened lower end of the parison in a closing operation, . The method of claim 3,
The parison extruded from the head core of the extruder is gripped and moved to the space between the first and second outer molds and the parison moved to the space between the first and second outer molds is firstly blow- And a parison robot for closing the upper end of the parison protruded upward from the mold. The method of claim 3,
A first inner mold and a second inner mold which are inserted through the mold, and at the time of inserting, an end portion of the parison penetrates the parison and is positioned inside the parison, Further comprising a needle pin having an air hole formed therein for blow molding. The method of claim 5,
In the first blow molding of the parison, the baffle pins into which the baffles are inserted are inserted into the parison in a state where the first and second inner molds and the first and second outer molds are both released, Wherein the plastic fuel tank is sealed after being closed by both the reconnaissance robot and the PCD. The method of claim 6,
After completion of the primary blow molding of the parison, the first and second inner molds move toward the parison so that the mold protrusions fix the baffle;
The baffle pin is moved down to the PCD position after the baffle is fixed by the mold projection;
The first and second outer molds are joined together after the baffle pin is moved downward;
After the first and second outer molds are assembled, the baffle pin is removed from the PCD and the PCD is closed to seal the bottom of the parison, thereby maintaining the parison's airtightness.
Characterized in that the parison is secondarily blow-molded in the shape of a plastic fuel tank through the air supplied through the needle pin after the needle pin is inserted into the parison through the parison in the airtight state of the parison Molding apparatus for plastic fuel tanks. A plastic fuel tank manufactured by the apparatus according to any one of claims 1 to 7, wherein a fusion line is formed on the surface of the fuel tank, and the fusion line is formed only in a straight line without a lump.

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