JP2949862B2 - Manufacturing method of piston with cooling cavity - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a piston with a cooling cavity, and is used, for example, as a method of manufacturing a piston of an internal combustion engine.

[0002]

2. Description of the Related Art As a prior art of a method of manufacturing a piston with a cooling cavity, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 60-15041.

In this prior art, a ceramic core mold is placed on a core mold, and then an outer mold is arranged around the core, so that a space between the core mold and the ceramic core mold and the inside of the outer mold is provided. A metal melt (for example, aluminum melt) is injected into the space formed. When the molten metal solidifies and the core and outer molds are removed, the piston is cast with the ceramic core remaining inside. Then, when the piston is forcibly vibrated, the ceramic core mold is collapsed and removed.

[0004] However, in such a ceramic core type removing means, there is a possibility that the core remains and it is difficult to confirm it.

[0005] Therefore, there has been proposed a type using a soluble core type (formed of, for example, a salt) having excellent removability. Here, the soluble core has a foot, and the end of the foot is exposed to the space from which the core inside the piston has been removed. Therefore, by injecting water or the like toward the foot, the soluble core remaining in the piston can be dissolved and removed. That is, the space from which the soluble core mold has been removed becomes the cooling cavity of the piston.

[0006]

As described above, since the soluble core type is generally formed of a small specific gravity material such as a salt, the specific gravity of the soluble core type is smaller than the specific gravity of the molten metal. There is a possibility that the soluble core type sometimes floats from the core type. Therefore, in the above-described prior art, a metal material (adsorbing means) is embedded at the end of the soluble core type foot, and a magnet (adsorbing means) is embedded at the contact position of the foot in the core type. ing. Therefore, the soluble core mold is fixed to the core mold via the metal material buried in the foot and the magnet, so that it does not float when the molten metal is poured.

However, according to this conventional technique, in order to remove the soluble core mold, the metal material must first be removed with a drill or the like, and the workability is poor and metal chips are generated. It has a problem that came up.

In view of the above, it is a technical object of the present invention to improve the removability of a member relating to an adsorption means embedded in a soluble core type foot in a method of manufacturing a piston with a cooling cavity.

[0009]

Configuration of the Invention

[0010]

Means for Solving the Problems A first technical means of the present invention taken to solve the above-mentioned technical problem of the present invention is a method for manufacturing a piston with a cooling cavity, which comprises a core type, a middle type and a medium type. An adsorbing means embedded in the core, a soluble core, and an adsorbed means formed by a screw member and embedded in the soluble core, wherein the soluble core is a core via the adsorbed means. Placed on the mold, inject the molten metal around the core and the soluble core, withdraw the core after solidification of the molten metal, and then dissolve and remove the soluble core after removing the adsorption means It is to be.

Further, a second technical means of the present invention taken to solve the above-mentioned technical problem of the present invention is to provide a method of manufacturing a piston with a cooling cavity in a core type and a core type. To be adsorbed, a soluble core type, and an adsorption means formed by a screw member and embedded in the soluble core type, and the soluble core type is disposed on the core type via the adsorption means. By injecting the molten metal around the core and soluble core, removing the core after solidification of the molten metal, and then dissolving and removing the soluble core after removing the adsorption means. is there.

[0012]

According to the first and second technical means of the present invention described above, since the suction means (or the suctioned means) embedded in the soluble core type is constituted by a screw member, it can be used with a driver or the like. It can be easily removed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the technical means of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a set state of a core mold 11 and a soluble core mold (formed of, for example, salt) 12 for manufacturing the piston 10 with a cooling cavity according to the embodiment of the present invention. As described above, the soluble core mold 12 is disposed on the core mold 11 via the screw member 13, and the number thereof is, for example, three.
However, the number of feet is not limited to three, and any number of feet may be used as long as the stability of the soluble core type can be obtained. Also,
As shown in the figure, in order to improve the retention of the screw member 13 of the soluble core 12, the engaging portion of the screw member 13 of the soluble core 12 may be raised.

Here, the screw member 13 is removed by a driver (not shown) or the like.

The suction means 14 is held on the core mold 11 via the holder 18 and has the same number as the number of the screw members 13.

The molten metal is poured into the space formed by the core mold 11, the soluble core mold 12, and the outer mold having the above-described configuration, and the solidification of the molten metal is completed. When removed, the piston coarse material is cast. here,
The soluble core 12 remains inside the piston coarse material, and the screw member 13 is exposed in the space from which the core 11 has been removed. Then, after the screw member 13 is removed by a driver or the like, the soluble core mold 12 is dissolved and removed by spraying water or the like toward the hole formed as a result.

Thereafter, secondary processing such as cutting is performed on the outer peripheral surface, the top surface, and the like of the piston coarse material, thereby completing the cooling cavity-provided piston 10 shown in FIG. The cooling cavity 14 is formed as a result of the removal of the soluble core 12 and the oil inlet 15 and the oil outlet 16 are connected to the screw member 1 as described above.
3 is formed as a result of the removal. Since there are three screw members 13, the screw members 13 that are not used for the oil inlet 15 and the oil outlet 16 are left as blind plugs 17 as they are. However, the screw member 13 left as the blind plug 17 is preferably fixed to the piston 10 by caulking or the like.

The operation of the cooling cavity is known from the above-mentioned Japanese Patent Application Laid-Open No. Sho 60-15041, and will not be described here.

In this embodiment, the magnet as the attracting means is embedded in the core type, and the screw member as the means to be attracted is embedded in the soluble core type. The magnetic material may be embedded in a soluble core type with a magnet screw member as a suction means. Alternatively, the adsorption means may be embedded in both the core type and the soluble core type.

Further, the soluble core form may be formed of a ceramic instead of a salt. However, in this case, the vibration is removed as in the conventional case.

[0022]

As described above, according to the present invention, since the suction means (or the suction target means) embedded in the soluble core type is constituted by a screw member, it can be easily removed by a driver or the like. it can. Further, since the screw member is reusable, it can contribute to cost reduction. Further, the passage after removing the screw member, which is not used for the oil inlet or the oil outlet to the cooling cavity,
By leaving the screw member as it is, no new blind plug is required.

[Brief description of the drawings]

FIG. 1 shows a set state diagram of a core mold 11 and a soluble core mold 12 for manufacturing a piston 10 with a cooling cavity according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the piston 10 with a cooling cavity according to the embodiment of the present invention.

FIG. 3 is a bottom view of the piston with cooling cavity 10 in FIG. 2;

[Explanation of symbols]

10 piston with cooling cavity, 11 core type, 12 soluble core type, 13 screw member, 14 suction means.

Claims (2)

(57) [Claims] 1. A core type, an adsorbing means embedded in the core type, a soluble core type, and an attracted means formed by a screw member and embedded in the soluble core type, The soluble core type is disposed on the core type through the adsorbing means, and a molten metal is injected around the core type and the soluble core type, and after solidification of the molten metal, the core is melted. A method of manufacturing a piston with a cooling cavity, which comprises extracting a mold, dissolving and removing the soluble core mold after removing the adsorption target means. 2. A method comprising: a core type; an adsorption means embedded in the core type; a soluble core type; and an adsorption means formed by a screw member and embedded in the soluble core type. The soluble core is disposed on the core via the adsorption means,
Injecting molten metal around the core type and the soluble core type, extracting the core type after solidification of the molten metal, and then dissolving and removing the soluble core type after removing the adsorption means. Manufacturing method of piston with cooling cavity.