JPH05116209A - Method and die for molding pipe fitted with flange - Google Patents

Abstract

PURPOSE:To provide a method and a die for molding a pipe fitted with a flange which is sufficient in strength of the product without generating a large amount of burr. CONSTITUTION:A parison 2 is held along the cavity 1 of a bottom force 3 in a state wherein a slide core 4 is moved to the outside. Then a top force 5 is closed and the air of the inside of the cavity 1 is exhausted. Thereafter gas is blown into the parison 2 and then the slide core 4 is moved to the inside and thereby a flange 6 is formed to a pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flanged pipe forming method for forming a filler pipe having a flange, for example, a flanged pipe connected to an on-vehicle gasoline tank without producing a large amount of flash, and a flange used therefor. The present invention relates to a mold for attached pipes (hereinafter abbreviated as a mold).

[0002]

2. Description of the Related Art As shown in FIG. 6, a flanged pipe connected to an on-vehicle gasoline tank comprises a three-dimensionally bent pipe main body 11 and a flange 6 projecting from the outer periphery of the main body 11. It has been done.

Conventionally, as the flanged pipe, a pipe main body 11 is first molded, and a flange 6 made of a separately molded metal is fitted and joined to the pipe main body 11. As a good product, a pipe with a flange in which the pipe body 11 and the flange 6 are integrated is directly blow-molded.

However, in the flanged pipe forming method, a wide parison must be used when forming a three-dimensionally bent pipe as illustrated in FIG. Therefore, burrs are generated around the molded product.
The volume ratio of the generated burr to the formed pipe is 8: 2 to
It is about 9: 1. Therefore, in the conventional flanged pipe forming method, a large amount of burrs is generated and the material is wasted. In addition, the treatment of a large amount of burrs generated in this way is also a problem.

Further, the both sides of the product thus formed have a structure in which parison is sandwiched in the thickness direction and cut and welded. Therefore, the product has a seam. Since the mechanical strength of this seam portion is low, there is also a problem that the flanged pipe molded by the conventional molding method has low strength.

As a method for solving the above-mentioned problems, there has been proposed a method of using a horizontal molding die composed of an upper die and a lower die to put a parison in the cavity of the lower die.

[0007]

According to the above-mentioned method, it is possible to solve the problem that a large amount is generated but the strength of the product is insufficient, which has been a problem. However, there is a problem that air easily accumulates in the cavity of the upper mold, particularly in the flange forming recess formed in the upper mold, and the flange is not formed into a desired shape.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in the method of forming a pipe with a flange according to claim 1, the lower mold is in a state where the slide core for forming the flange portion is located outside. Place the parison along the cavity of
Then, the upper mold is closed, and then the air in the cavity is exhausted by an exhausting means such as a vacuum pump, then gas is blown into the parison, the slide core is moved inward, and a flange is formed. I tried to solve it. When the flanged pipe is formed in this manner, it is desirable that the parison be housed in the lower mold cavity with both ends pre-pinched.

In the molding die of claim 2, an exhaust port is provided which communicates with the cavity only when the slide core is moved outward, and in which an opening on the cavity side is provided with a plug member made of a porous material. By doing so, the above problem was solved.

[0010]

According to the flanged pipe forming method of the present invention, the parison is housed along the cavity of the lower mold with the slide core positioned outside, then the upper mold is closed, and then the inside of the cavity is depressurized. Since gas is blown into the parison and the slide core is moved inward to form the flange, the parison can be brought into close contact with the wall surface of the flange forming recess for forming the flange.

In the molding die of claim 2, an exhaust port is provided which communicates with the cavity only when the slide core is moved outward and has a plug member made of a porous material attached to the cavity side opening. Therefore, the formation flange is not marked with the exhaust port, and the air in the cavity can be exhausted without sucking the parison into the exhaust port.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a sectional view showing a main part of a molding die of an embodiment. This molding die is composed of an upper die 5 and a lower die 3. The lower mold 3 and the upper mold 5 are composed of a main body 17 and a slide core 4. By closing the lower mold 3 and the upper mold 5, the cavity 1 is formed in a shape along the outer shape of the flanged pipe to be molded. The cavity 1 includes a front portion 18, a flange forming recess 10 and a rear portion 19.
It is formed from and.

The front portion 18 of the cavity 1 is the slide core 4
It is formed by the part of. The flange forming recess 10 is a space formed by the recess 21 formed in the main body 17 of the lower mold 3 and the upper mold 5 and the slide core 4. The rear portion 19 is formed by the main body portion 17. The slide core 4 is slidable in the thickness direction of the flange 6 in the main body 17, as indicated by an arrow A in FIG. The sliding of the slide core 4 changes the volume of the flange forming recess 10. Further, in this molding die, the end surface 15 of the slide core 4 and the side surface 16 of the concave portion 21 formed in the main body portion 17 are formed by tapering.

The recess 21 formed in the main body 17 of the lower mold 3 and the upper mold 5 is provided with an exhaust port 8 for discharging the air in the cavity 1 to the outside. A plug member 9 is provided at a location closest to the cavity 1 of the exhaust port 8. The plug member 9 is a porous metal in which a large number of holes are formed so that only resin can pass through but not resin.

In the molding die of this embodiment, as shown in FIG. 2, the exhaust port 8 is formed in the lower portion of the concave portion 21 of the main body portion 17 of the lower die 3 and in the upper portion of the concave portion 21 of the main body portion 17 of the upper die 5. It is provided in each place. The diameter of the exhaust port 8 was set to 5 mm. The exhaust port 8 is hidden under the slide core 4 when the slide core 4 is inside the mold, and is exposed when the slide core 4 moves to the outside position of the mold so as to communicate with the cavity 1. It is provided in.

An outer diameter of 50 m is obtained by using the molding die having the above construction.
m, the outer diameter of 100 mm on the peripheral surface of the pipe of 60 cm,
A pipe having a flange with a thickness of 10 mm was formed by the following procedure. With the slide core 4 of the lower mold 3 of the molding die being moved outward, as shown in FIG. At this time,
The cavity 1 and the exhaust port 8 are in communication with each other. As shown in FIG. 4, the mold was closed, and the air in the cavity 1 was exhausted by the vacuum pump from the exhaust ports 8 formed in the lower mold 3 and the upper mold 5. Air was blown into the parison 2. by this,
The parison 2 was molded into a shape along the cavity 1. As shown in FIG. 5, the slide cores 4 of the upper mold 5 and the lower mold 3 were moved inward. By moving the slide core 4 inward,
The parison 2 existing in the flange-forming recess 10 was crushed, whereby the flange 6 was formed on the pipe body 11.

In the flanged pipe forming method of this embodiment, the parison 2 is housed along the cavity 1 of the lower mold 3 while the slide core 4 is moved outward, and then the upper mold 5 is closed. Then, the air in the cavity 1 is exhausted. Then, air is blown into the parison 2 to form a hollow product. Then, the slide core 4 is moved inward, and the parison 2 existing in the flange forming recess 10 is moved.
Was crushed to form a flange. According to this method, the parison 2 can be brought into close contact with the wall surface of the flange forming recess 10. Therefore, in the flanged pipe forming method of the present embodiment, the parison 2 can be brought into close contact with the wall surface of the flange forming concave portion 10, so that the flange can be formed into 6 predetermined shapes.

In the molding die of this embodiment, the upper die 5 and the lower die 3 are provided with an exhaust port 8. When the slide core 4 is moved outward, the exhaust port 8 is provided with the cavity 1
It is formed at a position communicating with the flange forming recess 10. A plug member 9 made of a porous material is attached to the opening of the exhaust port 8 on the cavity 1 side. According to this mold, the air in the cavity 1 can be exhausted without sucking the parison 2 into the exhaust port 8. Therefore, in the molding die of the present embodiment, it is possible to prevent the exhaust port 8 from damaging the shape of the flange 6.

In the molding die of this embodiment, since the end surface 15 of the slide 4 and the side surface 16 of the main body 17 forming the flange forming recess 10 are tapered, when the slide core 4 is moved inward, Since the outer peripheral side of the flange 6 is gradually adhered, the flange can be formed without entraining air bubbles. Therefore, according to the molding die of the present embodiment, it is possible to prevent inconveniences such as strength reduction and leakage due to the presence of air bubbles in the flange portion 6.

[0021]

In the flanged pipe forming method of the first aspect of the present invention, the parison is accommodated along the cavity of the lower mold with the slide core positioned outside, then the upper mold is closed, and then the air in the cavity is closed. After removal, gas is blown into the parison and the slide core is moved inward to crush the parison and form a flange. According to this method, the parison can be brought into close contact with the wall surface of the flange forming recess. Therefore, in the flanged pipe molding method of the first aspect, the flange can be molded into a more predetermined shape.

In the molding die of claim 2, when the slide core is moved outwardly, the slide core communicates with the cavity, and the cavity side opening is provided with an exhaust port to which a plug member made of a porous material is attached. Therefore, the air in the cavity can be exhausted without sucking the parison into the exhaust port. Therefore, according to the molding die of the second aspect, it is possible to prevent the shape of the flange from being damaged by the exhaust port.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a molding die according to an embodiment.

FIG. 2 is a perspective view showing a lower slide core portion of the embodiment.

FIG. 3 is a cross-sectional view showing a state of a lower mold containing a parison in the embodiment.

FIG. 4 is a sectional view showing a state in which the mold is closed in the example.

FIG. 5 is a cross-sectional view showing a main part of a molding die after forming a flange in an example.

FIG. 6 is a perspective view showing an example of a flanged pipe.

[Explanation of symbols]

1 ... Cavity 2 ... Parison 3 ...
Lower mold 4 ・ ・ Slide core 5 ・ ・ Upper mold 6 ・ ・
Flange 8 ... Exhaust port 9 ... Plug member

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area // B29L 23:22 4F

Claims (2)

[Claims] 1. An upper mold and a lower mold having a cavity corresponding to the outer shape of a flanged pipe having a flange formed on the peripheral surface thereof, and at least one of the upper mold and the lower mold has a thickness of the flange. In the method of forming a flanged pipe using a flanged pipe forming die having a slide core that slides in the vertical direction, a parison is placed along the cavity of the lower die with the slide core moved outward. Pipe forming with a flange characterized by containing, then closing the upper mold, then exhausting the air in the cavity, blowing gas into the parison, and then moving the slide core inward to form a flange. Method. 2. An upper mold and a lower mold having a cavity corresponding to the outer shape of a flanged pipe having a flange formed on the peripheral surface thereof, and at least one of the upper mold and the lower mold has a thickness of the flange. A mold for a flanged pipe provided with a slide core that slides in the vertical direction, the plug member being in communication with the cavity when the slide core is moved outward and having an opening on the cavity side made of a porous material. A pipe forming mold with a flange, which is provided with an exhaust port to which is attached.