JP2001205642A - Method and mold for molding metal core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a process time of one cycle of a core casting apparatus without increasing the number of processes and to enable the arrangement of a resin injection molding apparatus and the core casting apparatus in a ratio of 1:1. SOLUTION: When a metal core having a thick-walled portion and a thin- walled portion is molded by casting, a core material core 13 comprising a metal having the same component as a metal of the metal core, for example, a core 11 for an intake pipe part or core 12 for a surge tank part in a drawing 1 is preformed to be prepared and this core is cast in the thick-walled part, for example, the core 12 for the surge tank part in the drawing 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for molding a low-melting metal core used in a lost core process and a mold for molding the same, and more particularly, to a method for manufacturing an automobile resin intake manifold. The present invention relates to a molding method suitable for producing a metal core having a thick part and a thin part, and a molding die for the same.

[0002]

2. Description of the Related Art In recent years, the method of manufacturing an intake manifold for an automobile engine has shifted from conventional aluminum alloy die casting to injection molding of a synthetic resin. Furthermore, due to the incorporation of multiple components and multi-functionality accompanying the use of resin, the external shape of the resin intake manifold is becoming more and more complicated. In recent years, as a manufacturing process of such a hollow resin intake manifold with a complicated shape,
The lost core process described below has come into wide use.

In the lost core process, a core simulating the shape of a hollow portion of a predetermined intake manifold, which is a target product, is set in a resin injection mold, and the core is injected by filling a molten resin. A portion corresponding to the intake manifold is formed around the core as the core. Take out this intake manifold together with the core, immerse it in a bath heated above the melting point of the core, melt and remove the core part that is the core, the core part becomes a hollow structure It is possible to manufacture a new resin intake manifold.

[0004] The core in this lost core process is:
Although it is melted and removed, since it is not preferable to heat it to a temperature higher than the deformation temperature of the synthetic resin constituting the intake manifold, a low-melting-point metal such as a tin-bismuth alloy whose melting point is usually about 140 ° C. is used. You. The core itself made of such a low-melting-point metal is cast by a casting apparatus provided with a molding die having a cavity formed in the shape of the core.

[0005] In the above-described intake manifold manufacturing line, the core casting device is disposed at a stage preceding the resin injection molding device of the intake manifold. Therefore, in order to match the process time of the subsequent resin injection molding apparatus, it is necessary to arrange two or three core casting apparatuses for one resin injection molding apparatus, and equipment cost for that purpose is required. The increase and securing of space were problems.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is possible to reduce the number of steps in the core casting process and reduce the time required for one cycle of core casting. The present invention provides a molding method and a molding die for a metal core, which can shorten the resin injection molding apparatus and the core casting apparatus in a one-to-one arrangement.

[0007]

SUMMARY OF THE INVENTION The above-mentioned problem is the same as that of the above-described metal core prepared and formed before casting and molding a metal core having a thick portion and a thin portion. This problem can be solved by the metal core molding method of the present invention, wherein a core material core composed of a metal component is cast into the thick portion.

[0008] Similarly, using the same mold and molten metal, a metal core having a thick portion and a thin portion, and a core material core set to be insertable into the thick portion. A metal core molding method in which the obtained core material core is cast into a thick portion of the metal core material at the time of the next casting, and the core material core obtained at that time is cast. The problem can also be solved by the method of forming a metal core according to the present invention, which is characterized by repeating casting into the thick portion of the next metal core.

Further, the above problem can be solved by the following metal mold for forming a metal core of the present invention. That is, the metal core molding die is
Forming a core core that can be cast at the same time as the metal core is cast in a molding die that has a cavity for casting corresponding to the shape of a metal core having a thick part and a thin part. The cavities are arranged in the same mold.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method for molding a metal core and a molding die according to the present invention will be described with reference to FIGS. First, a case of a 4-cylinder intake manifold will be described as an example of a core obtained by the present invention with reference to FIGS. 1 and 2. A core 12 for a surge tank portion of an intake manifold is provided with four cores 11 for an intake pipe portion. Are integrally connected, and the core 11 for the intake pipe portion has an elongated rod shape, whereas the core 12 for the surge tank portion has a relatively thick block shape.

According to the present invention, when a metal core having a thick portion and a thin portion, such as a core for an intake manifold, is cast and molded, the molten metal solidifies from a molten state and can be handled. In order to solidify the core, the solidification time of the thicker surge tank core 12 is longer than that of the intake pipe core 11, so that it is completed.

That is, according to the method of forming a metal core of the present invention, when a metal core having a thick portion and a thin portion is cast and formed, the metal core, for example, the intake shown in FIG. A core material core 13 made of the same metal as the pipe core 11 and the surge tank core 12 is formed and prepared in advance, and the thick core, for example, the surge core in the example of FIG. An important feature is that the core is cast into the core 12 for the tank portion, and thus the amount of molten metal in the thick portion can be reduced, so that the advantage that the solidification time can be shortened is obtained. Further, since the core material core 13 is made of a metal having the same components as the core 12 for the surge tank portion, when it is melted and removed in the subsequent lost core process, the recovered metal can be reused without separation. The advantage is obtained.

In this case, in the cross section of the obtained surge tank core 12, the core core 13 is completely cast into the surge tank core 12, as shown in FIG. 2A. In addition, the present invention includes a state where the core material core 13 is exposed as shown in FIG. 2 (B). In short, the use of the core material core 13 prepared in advance makes it possible to increase the thickness of the molten metal. Any amount can be used as long as the amount can be small and the object of the present invention is achieved.

Next, a second embodiment of the method of forming a metal core according to the present invention will be described together with an embodiment of a forming die. The method of forming a metal core according to the second embodiment uses a metal mold, for example, an intake manifold core, and a thick portion thereof, for example, a surge tank core 12 using the same mold and casting water. Core 13 set to be insertable
Is a method of molding a metal core in which the operations of individually and simultaneously casting are performed repeatedly, and the core material core 13 obtained each time is cast into a thick portion of the metal core at the time of the next casting. In addition, the present invention is characterized in that the core material obtained at that time is repeatedly cast into the thick portion of the metal core at the next time.

These steps and steps will be described in more detail with reference to FIGS. (FIG. 3) In a state where casting molding of one cycle is completed, the lower die 2 is shown after the upper die (the upper die is not shown) is opened, and a metal core in which the intake core 3 is used as an example. The core core 4 is shown with the upper half exposed from the lower mold 2. In this case, the side surfaces of the intake manifold core 3 and the core material core 4 are formed by the slide members 3a, 3b and 4a, 4b, respectively.

(FIG. 4) Core 3 for intake manifold
The slide members 3a and 3b are opened in order to pull out from the lower mold 2. (FIG. 5) A robot arm (not shown) pulls out the intake manifold core 3 from the lower die 2. (FIG. 6) The slide members 4a and 4b are opened to extract the core core 4 from the lower die 2. (FIG. 7) A second robot arm (not shown) extracts the core 4. (FIG. 8) A cavity 2 for molding the core 4 taken out from the core of the surge tank of the intake manifold.
1 (see FIG. 7) and placed.

(FIG. 9) The slide members 3a, 3b and 4a, 4b are moved and returned to their original positions during molding. In this case, the cavity 23 in which the core core 4 is to be cast and the cavity 22 for molding the intake pipe core of the intake manifold are completely blank. After that, through the steps of closing the upper mold (not shown), injecting a predetermined low-melting alloy into the core cavities 21 and 22 and the core core cavity 23, cooling and solidifying, etc. Returning to the state of FIG. 3, one cycle of casting is completed. Then, in the same manner, by repeating the casting, the core 4 manufactured at the time of the previous casting is inserted into the thick part and cast. Can also be shortened.

The mold for molding a metal core according to the present invention is suitably used in the above-described molding method.
As illustrated in FIGS. 3 to 9, the moldable cavities 21, 2 corresponding to the shape of a metal core having a thick portion and a thin portion, for example, a core 3 for an intake manifold.
In the molding die provided with 2, a cavity 23 for molding the core material core 4 set in a shape capable of being cast into a thick portion of the metal core is disposed in the same die, Casting of core 3 for intake manifold and core 4
Casting is also possible. In this case, the pouring way leading to the cavities 21, 22 and 23 is
It may be individually independent, but it is preferable to use a common runner because the casting operation can be simplified.

As described above, according to the metal core molding method and the molding die of the present invention, an already solidified core material core is prepared in advance and cast on a thick portion of the metal core. Since the metal core is cast in a round shape, the time required for cooling the thick portion is, for example, 100 seconds in the conventional case, but is reduced to 35 seconds or less in the present invention. It was found that it could be significantly reduced. Thus, the resin injection molding device and the core casting device are:
It is now possible to place them in one.

In the above description, the intake manifold for an automobile has been described as an example. However, in addition, a metal core having a thick portion and a thin portion such as a pump case and an air duct is required. In this case, the present invention is preferably applied, and is not limited to the core for an intake manifold for an automobile.

[0021]

The method for molding a metal core and the mold for molding the same according to the present invention are constructed as described above. And the core casting apparatus can be arranged in a 1: 1 ratio, and there is an excellent effect that equipment cost and equipment space can be reduced. Therefore, the present invention has a very large industrial value as a metal core molding method and a molding die for solving the conventional problems.

[Brief description of the drawings]

FIG. 1 is a perspective view of an intake manifold core obtained by the present invention.

FIGS. 2A and 2B are partial cross-sectional views of an intake manifold core. FIGS.

FIG. 3 is an explanatory view of a core casting process of the present invention.

FIG. 4

FIG. 5

FIG. 6

FIG. 7

FIG. 8

FIG. 9

[Explanation of symbols]

11 core for intake pipe part, 12 core for surge tank part, 13 core material core, 2 lower mold, 21, 22, 2
3 cavities, 3 cores for intake manifold,
3a, 3b slide member, 4 core material core, 4a, 4b
Slide member.

Claims (3)

[Claims] When a metal core having a thick portion and a thin portion is cast and formed, the metal core is prepared by molding in advance.
A method for molding a metal core, comprising: casting a core material core made of a metal having the same component as the metal core in the thick portion. 2. A metal core having a thick portion and a thin portion, and a core core set to be insertable into the thick portion at the same time using the same mold and molten metal. A method of molding a metal core, wherein the obtained core core is cast into a thick part of the metal core at the time of the next casting, and the obtained core core is then subjected to the next casting. A method of forming a metal core, comprising repeatedly casting a thick portion of a metal core. 3. A molding die having a cavity for casting according to the shape of a metal core having a thick portion and a thin portion, wherein the core can be cast simultaneously with the casting of the metal core. A mold for molding a metal core, wherein a cavity for molding a material core is provided in the same mold.