JPH106348A - Hollow core, its production and production of hollow resin product using hollow core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow core reduced in the use amt. of a low m.p. alloy and to produce a hollow resin product using the hollow core. SOLUTION: A low m.p. alloy layer 30 is formed on the outer peripheral surface of a pipe 10. The pipe 10 is made of aluminum or a heat-resistant resin. The low m.p. alloy layer 30 constitutes the molding region of a hollow resin product. The pipe 10 is arranged to a casting mold 20 and a low m.p. alloy is injected into the gap between the pipe 10 and the casting mold 20 to form the low m.p. alloy layer 30 on the outer peripheral surface 17 of the pipe 10. A hollow core A wherein the low m.p. alloy layer 30 is formed on the outer peripheral surface 17 of the pipe 10 is arranged in an injection mold and a resin is injected into the injection mold and the hollow core A and, thereafter, the pipe 10 and the low m.p. alloy are taken out of an injection-molded resin cured object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin intake manifold for connecting a carburetor of an automobile to an engine, a resin pipe for guiding air pressurized by a turbocharger to an intake side of the engine, and a radiator and a heater core. The present invention relates to a hollow core used for manufacturing a hollow resin product such as a resin tube, a method for manufacturing the same, and a method for manufacturing a hollow resin product using the hollow core.

[0002]

2. Description of the Related Art Conventionally, hollow resin products of this kind include:
For example, those described in JP-A-4-229236 are known. FIG. 3 shows an example of a hollow resin product.

[0003] Since this kind of hollow resin product 4 has a three-dimensional shape, it cannot be molded by ordinary injection molding. Therefore, a low-melting core method has conventionally been adopted. First, the core 1 is made of a low melting point alloy such as a Bi57-Sn43 alloy (melting point: 138 ° C., specific gravity: 8.7) by a core casting machine.
make.

Next, this is placed in an injection mold 2,
For example, 3 glass fibers on nylon 66 or nylon 6
0% by weight of a nylon resin, a polypropylene resin or the like is injected between the injection mold 2 and the core 1, and the core 1
Is formed around the substrate. Next, the core 1 on which the resin layer 3 is formed is taken out, and is heated in an elution tank (not shown) for the core 1 to elute the core 1 and to form the hollow resin product 4.
And

[0005]

As described above, in the low melting point core method, since the core 1 is made of a low melting point alloy, there are the following problems. For example, a core 1 of 10 kg or more is required to produce a resin dual duct of 500 g.

The core 1 needs skirting portions 5 at both ends in order to fix it in the injection mold 2. Therefore, the weight further increases. A large robot is required for taking out the core 1 from the core casting machine and setting it in the injection molding machine, and the equipment becomes large. A large robot is also required to remove the cored molded product after injection molding.

[0007] When the core is eluted, the core 1 corresponding to 10 kg takes 40 minutes at 180 ° C, and thus requires a large amount of electric energy. The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a hollow core in which the usage fee of a low melting point alloy is reduced, a method for producing the same, and a hollow resin product using the hollow core. It is to provide a manufacturing method.

[0008]

The invention according to claim 1 is characterized in that a low melting point alloy layer is formed on the outer peripheral surface of a pipe. The invention according to claim 2 is the hollow core according to claim 1, wherein the pipe is made of aluminum, iron, or a heat-resistant resin.

A third aspect of the present invention is the hollow core according to the first aspect, wherein the low-melting point alloy layer forms a molding region of a hollow resin product. The invention according to claim 4 is characterized in that a pipe is disposed in a casting mold, a low melting point alloy is injected between the pipe and the casting mold, and a low melting point alloy layer is formed on the outer peripheral surface of the pipe. is there.

According to a fifth aspect of the present invention, the hollow core according to the first aspect is disposed in an injection mold, and after the resin is injected between the injection mold and the hollow core, the resin is injected. A pipe and a low-melting-point alloy are taken out of a molded resin cured product.

(Function) In the invention of claims 1 to 4, first, the pipe is bent in accordance with the shape of the hollow resin product.

Next, the bent pipe is disposed in a casting mold, and a low melting point alloy is injected between the pipe and the casting mold.
A low-melting-point alloy layer constituting a molding region of a hollow resin product is formed on the outer peripheral surface of the pipe. Thereafter, a hollow core obtained by forming a low melting point alloy layer on the outer peripheral surface of the pipe from a casting mold can be obtained.

According to the fifth aspect of the present invention, a hollow core formed by forming a low melting point alloy layer on the outer peripheral surface of a pipe is disposed in an injection molding die, and the injection molding die and the hollow core are formed. For example, a nylon resin or a polypropylene resin obtained by mixing 30% by weight of glass fiber with nylon 66 or nylon 6 is injected between them. After the injection molding, the injection-molded cured resin is removed from the injection molding die.

Next, the cured resin is heat-treated in a low-melting alloy elution tank to elute the low-melting alloy. Thereafter, the pipe is taken out from the cured resin to obtain a hollow resin product.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a hollow core according to claims 1 to 4 and a method of manufacturing the same. First, FIG.
As shown in (a), two aluminum pipes 1
An aluminum pipe 10 in which the first and the first 12 are joined at one end 13 and 14 is prepared. Aluminum pipe 10
Is bent in accordance with a bifurcated hollow resin intake manifold.

Next, as shown in FIG. 1B, a bent aluminum pipe 10 is placed in a casting mold 20. The casting mold 20 includes an upper mold 21 and a lower mold 2 which are divided into two parts.
4. The upper mold 21 is made of Bi57-Sn4
A groove 22 filled with a low melting point alloy such as 3 alloy (melting point 138 ° C., specific gravity 8.7), and an aluminum pipe 10
And a step portion 23 for fixing the end portion 16.

The lower mold 24 is made of an aluminum pipe 10
A concave portion 25 into which the end portion 15 is fitted, a concave groove portion 26 filled with a low melting point alloy, and a step portion 27 on which the end portion 16 of the aluminum pipe 10 is placed.

Next, as shown in FIG. 1C, a low melting point alloy is injected between the outer peripheral surface 17 of the aluminum pipe 10 and the concave grooves 22 and 26 of the casting mold 20, and the aluminum pipe 10 The low melting point alloy layer 30 which forms the molding region of the hollow resin product is formed on the outer peripheral surface 17 of the substrate. Next, as shown in FIG. 1 (d), the hollow core A formed by forming the low melting point alloy layer 30 on the outer peripheral surface 17 of the aluminum pipe 10 is taken out from the casting mold 20.

Thus, the desired hollow core A can be obtained. As described above, according to the hollow core A according to the present embodiment, since the hollow core A includes the aluminum pipe 10 and the low melting point alloy layer 30, the conventional hollow core including only the low melting point alloy is used. Weight reduction is achieved as compared with.
Further, the equipment such as the core handling robot and the core transport conveyor can be miniaturized, and the capital investment can be reduced.

In this embodiment, the case where the aluminum pipe 10 is used has been described. However, the present invention is not limited to this, and any material having heat resistance of 260 ° C. or more and strength capable of withstanding the pressure during casting is used. For example, iron or a heat-resistant resin may be used. Further, the case where the aluminum pipe 10 is bent into a shape conforming to a bifurcated hollow resin intake manifold has been described. However, the present invention is not limited to this, and the bending process is performed according to the shape of the intended hollow resin product. Can be applied.

FIG. 2 shows an embodiment of a method for manufacturing a hollow resin product according to the invention of claim 5. Here, FIG.
The case where a hollow core A for a bifurcated hollow resin intake manifold formed by forming a low melting point alloy layer 30 on the outer peripheral surface 17 of an aluminum pipe 10 shown in (d) will be described. FIG. 2A shows the hollow core 1.

First, as shown in FIG. 2B, the hollow core A is placed in the injection molding die 40. The injection mold 40 includes an upper mold 41 and a lower mold 44 that are divided into two parts. The upper die 41 is made of, for example, nylon 66 or nylon 6 in which 30% by weight of glass fiber is mixed with nylon resin,
A groove 42 filled with a resin such as a polypropylene resin.
And a step 43 for fixing the end 16 of the aluminum pipe 10.

The lower mold 44 is made of an aluminum pipe 10
A concave portion 45 into which the end portion 15 is fitted, a concave portion 46 filled with resin, and an end portion 16 of the aluminum pipe 10.
And a step portion 47 for placing the Next, as shown in FIG. 2C, between the injection mold 40 and the hollow core A, for example, nylon 66 or nylon 6 in which glass fiber is mixed at 30% by weight, nylon resin, polypropylene resin, or the like. Inject resin.

After the injection molding, the injection-molded cured resin 5
0 is taken out of the injection mold 40. Next, the cured resin body 50 is subjected to a heat treatment in a low melting point alloy elution tank to elute the low melting point alloy. Thereafter, the aluminum pipe 10 is removed from the cured resin body 50.

Thus, as shown in FIG. 2D, a bifurcated hollow resin intake manifold (hollow resin product) 60 can be obtained. As described above, according to the method for manufacturing a hollow resin product according to the present embodiment, the hollow core A
Is made up of the aluminum pipe 10 and the low melting point alloy layer 30, so that it is extremely lightweight as compared with the conventional hollow core made only of the low melting point alloy, and is carried into the injection molding die 40. Carrying out after injection molding becomes easy.

Since the low-melting-point alloy is less expensive than the conventional low-melting-point core, the elution time of the low-melting-point core can be reduced. Of course, the elution equipment can be downsized.

[0028]

As described above, according to the first to fourth aspects of the present invention, since the pipe is constituted by the low melting point alloy layer covering the outer peripheral surface, the pipe is constituted only by the low melting point alloy. The weight is reduced as compared with the conventional hollow core.

Further, the equipment such as the core handling robot and the core transport conveyor can be miniaturized, and the capital investment can be reduced. According to the fifth aspect of the present invention, since it is composed of the pipe and the low-melting-point alloy layer covering the outer peripheral surface thereof, it is extremely lightweight as compared with the conventional hollow core composed only of the low-melting-point alloy. In addition, it is easy to carry into the injection mold and carry out after the injection molding. In addition, since the usage fee of the low melting point alloy is smaller than that of the conventional low melting point core, the elution time of the low melting point core can be reduced and the elution equipment can be downsized.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a hollow core according to claims 1 to 4 and a method for manufacturing the same.

FIG. 2 is an explanatory view showing one embodiment of the method for producing a hollow resin product according to claim 5;

FIG. 3 is an explanatory view showing a conventional low melting point core method.

[Description of Signs] 10 Aluminum pipe 17 Peripheral surface of aluminum pipe 10 20 Casting die 30 Low melting point alloy layer 40 Injection molding die 50 Resin cured body 60 Bifurcated hollow resin intake manifold (hollow resin product) A Hollow core

Claims (5)

[Claims] 1. A hollow core comprising a low melting point alloy layer (30) formed on an outer peripheral surface (17) of a pipe (10). 2. The hollow core according to claim 1, wherein the pipe is made of aluminum, iron, or a heat-resistant resin. 3. The hollow core according to claim 1, wherein the low melting point alloy layer (30) constitutes a molding region of a hollow resin product. 4. A pipe (10) is disposed on a casting mold (20), a low melting point alloy is injected between the pipe (10) and the casting mold (20), and an outer peripheral surface (17) of the pipe (10) is provided. A) forming a low melting point alloy layer (30) on the hollow core. 5. The hollow core according to claim 1, which is disposed in an injection mold (40), and a resin is injected between the injection mold (40) and the hollow core. A method for producing a hollow resin product using a hollow core, wherein a pipe (10) and a low melting point alloy are taken out of an injection-molded cured resin (50).