JPH01316244A - Blow molded product and its manufacture - Google Patents

Abstract

PURPOSE:To retain high bonding strength at a bonded section by disposing an external side flange and an internal flange on an outer periphery of a pipe- shaped insert burying end through an intermediate recessed section, and wrapping the outer flange integrally by means of resin constituting a main body of a molded product coming into an intermediate recessed section. CONSTITUTION:Two flange sections, an outer flange 32 and an inner flange 33, are disposed from the edge side to the center through an intermediate recessed section 34 on the outer periphery of a buried end section 31 of a pipe- shaped insert 30, and the flanges 32 and 33 are formed round normally. Generally the outer flange 32 buried in a molded product main body 20 is formed lower than the inner flange 33. Recessed resin 21 constituting the molded product main body 20 comes into the intermediate recessed section 34 pinched between the two flanges to wrap integrally the outer flange 32. Thus, an extremely strong bonded structure can be provided at a bonded section of the pipe-shaped insert and the main body section of a blow molded product, particularly in the blow molded product using a branch pipe.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a blow molded product and a method for manufacturing the same, and particularly relates to a blow molded product having a pipe-like product such as a branch pipe integrally used in piping for air conditioning equipment of vehicles. related to products and their manufacturing methods. (Prior art) For example, in the engine compartment of a car, a pipe is sometimes installed to supply compressed air from a supercharger to the engine, but since this pipe is close to the engine, it is generally not heat resistant. A certain metal tube was used. However, in recent years, due to demands for weight reduction, plastics with heat resistance, such as glass m! Attempts have been made to make plastics using reinforced polyamide resins. This type of air conditioning pipe often has a complicated curved shape because it is routed to avoid various equipment in the engine room or has a branch structure. This is advantageously achieved by blow molding.

By the way, conventionally, in order to obtain a tubular product having this kind of branched structure by blow molding, for example,
Like the molded product 60 shown in the figure, a pipe-shaped injection molded product 70 (usually referred to as an insert or insert pipe) with a flange 71 at one end, which will serve as a branch pipe, is inserted into the molded product cavity with the flange 71 side. The insert pipe 70 is placed in a mold so that the insert pipe 70 is positioned in the same position as the insert pipe 70, and then the parison is blown so that the expanded parison is brought into close contact with the flange 71 of the insert pipe 70, and the insert pipe 70 is integrally molded. In addition, after cooling the molded product, the insert pipe 7
The main body resin 61 portion that closes the branch opening 75 of the insert pipe is removed from the opening of the insert pipe using a drill or the like to obtain a product.

However, this conventional technique has a problem in that the bonding strength between the insert pipe and the molded product main body 61 is low. In other words, when the insert pipe and the molded product body resin are both made of polyethylene resin with a low melting temperature, the flange surface of the insert pipe may partially melt due to the heat retained in the parison, and as a result, it may be welded together with the main body. However, in the case of resins with high melting temperatures, such as glass fiber reinforced polyamide resins as mentioned above, it is almost impossible for the insert pipe and the main body resin to be welded together even if they are made of the same or the same type of compatible plastic. Instead, the molten parison is simply blown and crimped onto the surface of the flange 71 of the insert pipe 70, resulting in a close contact with the surface, giving the appearance of a welded or bonded structure.

Note that the insert pipe 70 may be preheated in order to weld it to the parison when it is installed in the mold, but if it is heated to too high a temperature, it may be thermally deformed and the predetermined pipe shape may not be maintained.

Therefore, the flange 7 of the insert pipe 70 is
1 and the main body resin 61 have a mere planar close contact structure as shown in FIG. 12, the close contact surface of the insert pipe is There is a tendency for gaps to form between pipes, and joints tend to be destroyed when pressure is applied after piping is installed, and there is always a risk of problems such as fluid leakage or breakdowns within the pipes.

(Problems to be solved by the invention) In view of the above-mentioned problems, this invention provides a molded product in which a pipe-shaped insert and a molded product body are integrally molded, and the joint portion thereof maintains high joint strength. This paper proposes a new structure that can be used to create a new structure, and a method that can reliably mold this structure.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention first provides a blow-molded product in which the end of the pipe-like insert is embedded integrally in the molded product body. An outer flange and an inner flange are provided on the outer periphery of the buried end of the molded article via an intermediate recess, and at least the resin constituting the molded product body enters the intermediate recess and integrally encloses the outer flange. We propose blow molded products with special characteristics.

In addition, in order to obtain a blow molded product in which the north pipe-shaped insert is integrally buried, an outer flange and an inner flange are provided on the outer periphery of the buried end of the pipe-shaped insert via an intermediate recess, and the intermediate recess is connected to the outside of the cavity. A vent is formed, the insert is placed in the molded product cavity, and a parison is blown to allow the remaining air in the intermediate recess to escape from the vent to the outside, and the resin constituting the molded product body is removed from the intermediate cavity. The present invention proposes a method for manufacturing a blow molded product, characterized in that the outside flange is inserted into a recess and integrally wrapped and molded.
(Function) As described above, in the blow molded product of the present invention, at least the resin constituting the molded product body is introduced into the intermediate recess of the outer flange and the inner seven flange of the pipe-like insert, and the resin is inserted into the outer flange. It has a structure in which it is wrapped and joined integrally with the molded product body. However, the molded part that covers the outer flange and the molded part that has entered the intermediate recess are annular along the outer surface of the pipe, and when cooling them, they are direction), so it tightly adheres to the outer 7 flange of the pipe-shaped insert and the intermediate recess itself so as to bite into it. Furthermore, the contact surface extends over the entire joint surface from the outer flange to the intermediate recess, creating a strong joint structure as a whole.

On the other hand, when obtaining the above-mentioned molded product, an insert pipe with an outer flange and an inner flange provided on the outer periphery of the buried end via an intermediate recess is installed in the mold and the parison is blown. In this case, the expanded parison is present at the top of the two flanges almost simultaneously, so that
Air in the intermediate recess between these flanges tends to become trapped. However, in the second invention, since a ventilation portion communicating with the outside of the cavity is formed in the intermediate recess,
As the parison expands into the recess, the air within the recess is forced out of the cavity through the ventilation section, allowing the resin of the molded article to effectively enter the inner surface of the recess.

(Example) The present invention will be described in detail below with reference to the accompanying drawings. Figure 1 is a partial perspective view showing an example of a tubular molded product made by integrally blow-molding a pipe-shaped insert, Figure 2 is a vertical sectional view showing the joint of the molded product in Figure 1, and Figure 3 is a similar view of the same. 4 is a partial sectional view of the mold showing the molding state of the molded product shown in FIG. 1, and FIG. 5 is a partial sectional view of the mold according to another example shown for comparison. Fig. 6 is a partially cutaway sectional view showing another example of the pipe-shaped insert, Fig. 7 is a side view thereof, Fig. 8 is a sectional view of 8-8MA in Fig. 6, and Fig. 9 is a pipe-shaped insert. A partially cutaway sectional view showing another example of a shaped insert, FIG. 1O is a side view thereof, p! FIG. ll11 is a sectional view taken along the line 11-11 in FIG. 9.

(First Embodiment) FIG. 1 is a perspective view showing an example of a tubular molded product P according to the present invention, and FIGS. 2 and 3 are cross-sectional views of a joint with a pipe-shaped insert 30 in this product. be.

As is clear from the figure, this tubular molded product P is a blow molded product in which one end (embedded end 31) of a pipe-shaped insert 30 is embedded in the molded product main body 20 as follows. It has a unique joint structure.

That is, on the outer periphery of the buried end 31 of the pipe-shaped insert 30, two flange parts, an outer flange 32 and an inner flange 33, are provided in order from the edge side with an intermediate recess 34 interposed therebetween. These flanges 32 and 33 are usually configured in a substantially circular shape, and the outer flange 32 embedded in the molded product body 20 is generally configured to be smaller than the inner flange 33.

Then, the resin 21 constituting the molded product main body 20 enters the intermediate recess 34 sandwiched between the two flanges and integrally wraps the outer flange 32.

Reference numeral 35 in FIGS. 2 and 3 is a through hole serving as a ventilation portion, and 36 is a stepped portion that engages with the main body resin on the inner surface of the insert.

FIG. 4 is a cross-sectional view of a mold 90 for manufacturing the above-mentioned tubular molded product P.
A through hole 35 serving as a ventilation portion communicating with the outside of the cavity 91 is formed in the intermediate recess 34 of the insert pipe 30 provided with the two inner flange 33 and the intermediate recess 34 .

This insert pipe 30 is placed so that its buried end 31 is located in the molded product cavity 91 using a nesting mold 95 as shown in the figure.6 Next, the parison is blown by a known method, and the insert pipe 30 and Molded product body 2
0 is molded into one piece.

During this integral molding, as mentioned above, the intermediate recess 3
Residual air that may be trapped inside 4 is allowed to escape to the outside through the through hole 35, which is the ventilation section, and the resin 22 constituting the molded product body reliably enters the intermediate recess 34, and the outer flange 32 is integrally assembled with the outer flange 32. wrap it in.

For comparison purposes, FIG. 5 shows a case in which molding is performed using an insert pipe 3OA in which no ventilation section is provided in the intermediate recess 34. However, when using this insert pipe 3OA, as shown in the figure, the intermediate recess 34 The remaining air inside the mold is trapped.

Therefore, the main body resin 21 cannot reliably enter into the intermediate recess 34, and a gap C as shown in the figure is formed.This gap C makes the outer flange 32 incompletely covered by the main body resin. In addition, the effect of the body resin 22 in the intermediate recess 34 biting into the outer peripheral surface of the pipe is lost, and the bonding strength at the joint is significantly reduced.

(Second Embodiment) FIGS. 6 to 8 relate to another embodiment. The insert pipe 40 used here has an outer flange 42 and an inner flange 43 provided on the outer periphery of the buried end 41 of the insert via an intermediate recess 44.
3 has a through hole 45 which is a ventilation section from the intermediate recess 44 to the outside.
45... are provided. Although four through holes 45 are provided in the embodiment as shown in FIG. 8, it goes without saying that the number can be determined as necessary.

Regarding the outer flange 42 shown in FIG. 7, the reference numeral 46 is a stepped portion for engaging with the main body, and the reference numeral 47 is a notch for preventing rotation.

The molding method using this insert pipe 40 is substantially the same as that of the first embodiment, so the explanation will be omitted. In this embodiment, since a notch 47 is provided in the outer flange 42, a part of the parison blown during molding enters the notch, creating an anchor effect and preventing the insert pipe from rotating with the molded product body. achieved.

(Third Embodiment) In the third embodiment, the through hole 45 in the insert pipe 40 of the above embodiment becomes a notch 55, and resin is inserted into the notch 55 to provide ventilation and a rotation prevention effect at the same time. That is.

Regarding the insert pipe 50 shown in FIGS. 9, 10, and 11, reference numeral 51 indicates a buried end, 52 an outer flange, 53 an inner flange, 54 an intermediate recess, and 55
56 is a notch serving as a ventilation portion, 56 is an engaging stepped portion, and 57 is a notch for preventing rotation of the outer flange.

The molding method using the insert pipe 50 according to this example is also the same as the previous example, so the explanation will be omitted.

(Effects) As illustrated and explained above, the blow molded product according to the present invention, particularly the blow molded product having a branch pipe, has an extremely strong bonding structure at the joint between the pipe-shaped insert and the main body. Now I can do it. Therefore, it was possible to provide a plastic pipe suitable for use in air conditioning equipment for automobiles, etc., which requires heat resistance, vibration resistance, durability, etc.

Moreover, according to the method according to the present invention, a blow molded product having an upper branch pipe can be reliably obtained by extremely simple and simple means.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view showing an example of a tubular molded product in which a pipe-like insert is integrally blow-molded, and FIG. 2 is a longitudinal cross-sectional view showing a joint of the molded product shown in FIG. 1. Fig. 3 is a cross-sectional view of the same, Fig. 4 is a partial sectional view of the mold showing the molding state of the molded product shown in Fig. 1, and Fig. 5 is a cross-sectional view of another example shown for comparison. FIG. 6 is a partially cutaway sectional view showing another example of a pipe-shaped insert, FIG. 7 is a side view thereof, and FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 6. 9 is a partially cutaway sectional view showing another example of a pipe-shaped insert, FIG. 10 is a side view thereof, and FIG. 11 is a sectional view taken along line 11-11 in FIG. 9.
FIG. 12 is a cutaway sectional view showing an example of a tubular molded product in which a conventional pipe-shaped insert is integrally blow-molded. 20... Molded product body, 30.40.50... Insert pipe, 31, 41.51... Buried end, 32.
42.52...Outer flange, 33, 43. 53...Inner flange, 34,44.54...Intermediate recess, 35.45...Through hole, 55...Notch. 1 Figure P and Figure 2 Figure 3 Figure 4 Ku Atsushi 5 Ku Pu 6 Go No. 75 □8 Figure 47 45 Figure 9 Figure 10 Figure 11

Claims (1)

[Claims] 1. In a blow-molded product in which the end of the pipe-shaped insert is embedded integrally in the molded product body, an outer flange and an inner flange are provided on the outer periphery of the embedded end of the pipe-shaped insert through an intermediate recess. A blow molded product, wherein at least a resin constituting the molded product body enters the intermediate recess and integrally encloses the outer flange. 2. An outer flange and an inner flange are provided on the outer periphery of the buried end of the pipe-shaped insert via an intermediate recess, and a ventilation portion communicating with the outside of the cavity is formed in the intermediate recess;
The insert is placed in the molded product cavity and a parison is blown to allow the remaining air in the intermediate recess to escape to the outside through the ventilation portion, and to prevent the resin constituting the molded product body from entering the intermediate recess. A method for manufacturing a blow molded product, characterized in that the outer flange is integrally wrapped and molded.