JPH0653459B2 - Molding method for synthetic resin filler tubes - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a blow molding method of a filler tube used in connection with a gasoline inlet of a fuel tank for injecting gasoline into the fuel tank.

[Prior art]

Recently, automobile fuel tanks are made of synthetic resin from the viewpoints of weight reduction and flexibility in shape design, and the filler tubes used in connection with the fuel tank are also made of synthetic resin. ing.

The following are known as conventional synthetic resin filler tubes.

First, as a first technique, as shown in FIG. 9, when the filler tube is molded by blow molding, the bulging portion 4 is formed at the tip of the filler tube main body 2, and after molding or molding. There is one in which the flange 3 is formed by cutting at the position of reference numeral 5.

As the second technique, as shown in FIG.
There is a filler tube body 6 in which a disc body 7 having an opening at the center manufactured by injection molding or the like is welded to an end portion of the filler tube body 6 to form a flange portion.

As a third technique, as shown in FIG.
There is one in which a flange body 8 having an insert portion 8A manufactured in advance by injection molding is inserted into an end portion of a filler tube main body 9 during blow molding of a filler tube to form a flange portion.

[Problems to be Solved by the Invention]

The flange portion of the filler tube is a portion that is required to have sufficient reliability, for example, by fastening bolts and nuts to the fuel tank so that structural strength as a connecting portion is required. However, the above-mentioned conventional technique has the following problems.

In the first technique, since the bulging portion 4 is stretched by blowing, the bulging portion 4 is thinner than the wall thickness of the filler tube main body 2, which causes a problem in strength and lacks reliability. Further, since it is stretched in the radial direction by blowing, it becomes thinner toward the outside of the flange portion 3 forming portion and processing to a uniform thickness is required, and the number of working steps increases accordingly.

Further, in the second technique, there is a problem in the welding strength of the welded portion and the reliability is poor. Further, the disk body 7 forming the flange portion has to be manufactured in a separate process, and there are many manufacturing processes, resulting in an increase in cost.

Further, in the third technique, there is a problem in the airtightness of the connection surface of the flange body 8 to the end portion of the filler tube main body 9 and reliability is lacking. Further, as in the case of the second technique, the flange body 8 has to be manufactured in a separate process, resulting in an increase in cost.

The present invention has been made in view of the above problems of the prior art,
The purpose is a blow molding method of a filler tube in which a flange portion for connecting to a fuel tank is formed at an end,
It is to provide a method capable of forming the thickness of the flange portion to be thicker than the wall thickness of the tube body.

[Means for solving problems]

In order to achieve the above object, in the blow molding method of a synthetic resin filler tube according to the present invention, a synthetic resin in which a flange portion for connecting to a fuel tank is integrally formed with the tube body at one end of the filler tube body. A blow molding method for a filler tube made of metal, wherein at the time of blow molding, the press die is slid against the mold for molding the filler tube main body in the direction opposite to the direction of supplying the parison to bring the end of the parison into contact with the main body of the tube. A thick flange portion thicker than the wall thickness of the tube body is formed at the end portion of.

[Action]

By sliding the press mold against the mold for molding the filler tube main body in the direction opposite to the direction of supplying the parison, the edges of the parison are brought closer to each other, and the thickness of the filler tube main body on the outer periphery of the end of the filler tube main body. A thicker flange portion thicker than the above is formed.

〔Example〕

 Next, an embodiment of the method of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing a state in which a filler tube manufactured by the method of the present invention is connected to a fuel tank.

In this figure, the filler tube 10 has a structure in which a flange portion 14 is formed integrally with the tube body 12 at the end of the tube body 12, and is made of synthetic resin such as high-density polyethylene. The flange portion 14 is a connecting portion to the fuel tank 20, and bolt holes 16 are formed at a plurality of positions in the circumferential direction of the flange portion 14. As will be described later, the flange portion 14 is press-molded by a press die that slides in the direction opposite to the parison supply direction during blow molding of the filler tube to have a sufficiently thick portion as compared with the tube body 12, and a large bolt. It can also withstand the fastening force. A reference guide portion 13 of a size just capable of engaging with a gasoline inlet 22 of a fuel tank 20 described later is provided at a lower position of the flange portion 14, and the reference guide portion 13 inserts the filler tube 10 into a gasoline injection pipe. It serves as a positioning member when it is attached to the inlet 22.

Reference numeral 21 is a fastening bolt, reference numeral 22 is a gasoline inlet of the fuel tank, reference numeral 23 is a ring-shaped plate arranged around the gasoline inlet 22, and reference numeral 23A is a bolt 21 screw formed on the plate 23. A female screw portion which is a joint portion, a reference numeral 24 is an O-ring, a reference numeral 26 is a retainer arranged in contact with the flange portion 14, and a reference numeral 28 is attached to an inner peripheral wall of the tank so as to surround the gasoline inlet 22 of the fuel tank. It is a reinforcing member.

Thus, in the filler tube 10, the flange portion 14
Is integrally molded with the filler tube main body 12 and has a wall thickness sufficiently larger than the wall thickness of the filler tube main body 12, so that the tightening force of the flange portion 14 by the bolt 21 is increased and The mounting strength can be increased.

FIG. 2A shows a molding apparatus for blow molding the filler tube 10 shown in FIG.

In this figure, reference numerals 40A and 40B denote a pair of metal molds (40) that are arranged facing each other with a parison 32 supplied from a parison supply nozzle (parison extrusion port) 30 in between.
A is a left mold and 40B is a right mold). Mold 40
A and 40B are indicated by arrows A and B by a driving device (not shown).
It is slidable in the front-rear direction, and on its opposite surfaces, first molding surfaces 41A, 41B that match the outer shape of the filler tube main body 12 to be molded are formed. At the lower ends of the first molding surfaces 41A, 41B, the first molding surfaces 41A, 41B are provided via the step portions 42A, 42B.
Second molding surfaces 43A and 43B deeper than B are respectively formed, and the flange portion 14 is molded within the second molding surfaces 43A and 43B.

A molding surface 41 is provided on each of the facing surfaces of the molds 40A and 40B.
A, 41B; pinch-off portions 44A, 44B are provided so as to surround 43A, 43B, and the molds 40A, 40B.
Is slid in the directions of arrows A and B to pinch the supply parison 32.

The cylinder mechanisms 50A, 50 are provided in the molding surfaces 43A, 43B.
Lower molds 45A and 45B that can be slid vertically by B
(The lower left mold is 45A and the lower right mold is 45B). As shown in FIG. 3, the lower molds 45A and 45B have a substantially semi-cylindrical shape in which a columnar body is halved in the vertical direction, and the mold 40 is provided at the center of the upper end surface forming the press surface.
Recesses 46A and 46B having the same diameter as the molding surfaces 41A and 41B formed on the A and 40B are formed. Further, pinch-off portions 47A and 47B, which are flush with the pinch-off portions 44A and 44B of the dies 40A and 40B, project from the opposing surfaces of the dies 45A and 45B along the outer peripheral edge portion. Supply parison 32 in cooperation with
To pinch.

Cylinder mechanism 50A (50B) is a mold 40A (40B)
A pair of cylinders 52A (52B) and a telescopic rod 54 mounted and fixed on both side walls (in the direction perpendicular to the paper surface of FIG. 2 (a)).
A (54B) and a cylinder 52A
The operation of (52B) is performed by a horizontal mount 56A (56) that supports the molds 45A and 45B via the telescopic rod 54A (54B).
B) is slid vertically. As a result, the lower mold 45A (45B) is formed on the molding surface 43A (43B).
Moves up and down along. Lower molds 45A, 45B, pinch-off portions 44A, 44B of left and right molds 40A, 40B
When they are in close contact with each other, one lower mold 45 having a cylindrical shape is formed in cooperation with each other, and a total of four cylinder mechanisms 50A and 50B are provided.
By interlocking the individual cylinders 52A, 52A, 52B, and 52B, the cylinders 52A, 52A, 52B, and 52B slide integrally in the molding surfaces 43A and 43B. Reference numeral 34 is an air pipe for supplying air into the pinched parison.

Next, the blow molding method according to the present invention will be described with reference to FIGS. 2 (a) to 2 (d).

First, as shown in FIG. 2 (a), when a predetermined amount of parison 32 is supplied from the parison supply nozzle 30, the pair of molds 40A and 40B are moved closer to each other, and as shown in FIG. 2 (b). Pinch the parison 32 as shown.
Air is then supplied by the air pipe 34 into the pinched parison 32. Then, as shown in FIG. 2 (c), the parison 32 has the molding surfaces 41A and 41B of the mold;
43A, 43B and recesses 46A, 46B of the lower mold 45
The bulge 32A is pressed by the inner peripheral surface and is located below the parison 32.
Is formed. Then, as shown in FIG. 2 (d),
Lower mold 45 by interlocking cylinder mechanisms 50A and 50B
(Composed of 45A and 45B) is slid upward and cooperates with stepped portions 42A and 42B to bulge 32A of parison 32.
Is pressed to form the thick flange portion 32B. This state is maintained until the parison 32 (resin molding) in the mold is cooled and solidified. Then, after the molding is completed, the molded body is taken out, the end portion is cut at the position indicated by reference numeral 36 in FIG. 4, and the reference guide portion 13 is formed at the lower end portion of the filler tube. Other finishing work such as deburring is completed to complete the molding of the filler tube.

In the manufacture of the filler tube, the parison 32 supplied from the parison supply nozzle 30 uses a so-called small diameter parison which is smaller than the shape of the molding surfaces 41A and 41B of the mold, but the molding surfaces 41A and 41B.
It is also possible to use a so-called large-diameter parison that is larger than the shape of the left and right molds 40A, 4 in this case.
When pinched at 0B, the state is close to that shown in FIG. 2 (c).

Further, in the molding apparatus, the recesses 46A and 46B are formed on the upper end surface which is the pressing surface of the lower mold 45 (45A, 45B) for press-molding the flange portion, but as shown in FIG. The upper surface of the lower mold 45 may be a flat surface, and in this case, a molded body having a flat lower surface of the flange portion 32B as shown in FIG. 6 can be obtained.
In the molded body shown in FIG. 6, the portion indicated by reference numeral 38 may be cut and removed into a circular shape to form an opening in the central portion of the flange portion.

FIG. 7 shows another embodiment of the molding apparatus.

In the molding apparatus shown in the above-mentioned embodiment, the air pipe is provided on the parison supply side, but in this embodiment, the air pipe is provided on the lower mold side for press-molding the flange portion.

In FIG. 7, the air pipe 34A is a molding surface 41 of the mold.
While extending into the inside of A and 41B, the outer peripheral surface of the tip is located at a position separated from the molding surfaces 41A and 41B by an amount corresponding to the thickness of the parison 32, and along the outer surface of the air pipe 34A, the lower die 55 ( The lower left mold 55A and the lower right mold 55B) can slide vertically. Others have the same structure as that of the blow molding device and are denoted by the same reference numerals, and detailed description thereof will be omitted.

The procedure for molding the filler tube by using the molding apparatus shown in FIG. 7 is as follows.
After pinching with A and 40B, first, the lower die 55 is slid upward as shown in FIG. 8 to press the flange portion 32B. Then, after that, air is supplied by the air pipe 34A to perform blow molding. This point is different from the molding procedure by the molding apparatus shown in FIG. 2 in which the flange portion is press-molded after the air is supplied or while the air is supplied. The other molding procedure is the same as that of the molding apparatus shown in FIG. 2 and its description is omitted.

〔The invention's effect〕

As is clear from the above description, according to the method of the present invention, the flange for connection to the fuel tank, which was considered to be thicker than the wall thickness of the tube body in the conventional blow molding, was not It can be formed thicker than the thickness. Therefore, since a filler tube having a strong attachment strength can be obtained, a highly reliable filler tube / fuel tank connection structure can be obtained by fastening the filler tube and the fuel tank with a large fastening force.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part of a filler tube manufactured by the method of the present invention, FIG. 2 (a) is a front view showing a part of a molding apparatus for molding a filler tube in a sectional view, and FIG. 2 (b). ) To FIG. 2 (d) are explanatory views for explaining the operation of the molding apparatus, FIG. 3 is a perspective view of an essential part of the molding apparatus, and FIG. 4 is a cross-sectional view of an essential part of a molded product molded by the molding apparatus. FIG. 5 is a longitudinal sectional view of a main part of another embodiment of the molding apparatus, FIG. 6 is a cross-sectional view of a main part of a molded body molded by another molding apparatus, and FIG. 7 is a further molding apparatus. FIG. 8 is a longitudinal sectional view showing the operation, FIG. 8 is an explanatory view for explaining the operation thereof, and FIGS. 9 to 11 are explanatory views for explaining a conventional procedure for manufacturing the filler tube. 10 ... Filler tube, 12 ... Tube body, 1
4 ... Flange part, 32 ... Parison, 34, 34A ...
... air pipe, 40A ... left mold, 40B ... right mold,
45, 55 ... lower mold, 45A, 55A ... lower left mold,
45B, 55B ... Lower right mold.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area F16L 23/02 23/032

Claims (1)

[Claims] 1. A blow molding method for a synthetic resin filler tube in which a flange portion for connecting to a fuel tank is integrally formed with the tube body at one end portion of the filler tube body. Slide the press die in the direction opposite to the parison supply direction against the die for use to reduce the thickness of the parison end, and form a thick flange on the end of the tube body that is thicker than the thickness of the tube body. A blow molding method for a synthetic resin filler tube, characterized by: