JPH08309512A - Casting device - Google Patents

Abstract

PURPOSE: To improve the quality and the precision of a cast product and to reduce the cost required for deburring work by closing the upper part of a reduced pressure flask with a film and communicating a lower chamber with an evacuation source. CONSTITUTION: The upper opening part 3d of the reduced pressure flask 3 is closed with the film 5, and in the lower chamber 3b, gas exhaust hole 3c is arranged and communicated with the evacuation source P. When the pressure in the lower chamber 3b of the reduced pressure flask 3 is reduced with the evacuation source P, the pressure of an upper chamber 3a is reduced through a filter 4, and since the opening part 3d is closed with the film 5, the atmospheric pressure exerts on the film 5, but the pressure of the chamber 3a is equalized with that of the chamber 3b through the dry sand 6 and the negative pressure is uniformly applied to the whole surfaces of a cope 1 and a drag 2. At the time of pouring molten metal into a sprue 7, the gas generated in the cope 1 and the drag 2 is quickly diffused into the flask 3. By this method, the development of a gap of the joining surface between the cope and the drag is restrained by the uniformity of pressure applied to the molds together with the effect of rapid diffusion of the gas, and the development of burr is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting device for pouring molten metal into a mold having an upper mold and a lower mold.

[0002]

2. Description of the Related Art FIG. 2 and FIG. 3 show the state of casting by a conventional casting apparatus. In FIG. 2, the upper mold 1A is attached to the lower mold 2A.
And the weight W is placed on the upper mold 1A. Further, in FIG. 3, the flange portion F of the upper die 1B and the lower die 2B is fastened with bolts B and the like, and pouring is performed.

However, gas is generated in the mold during pouring, the pressure acts on the mating surface S between the upper mold 1A and the lower mold 2A to form a gap, and the molten metal flows into the gap and solidifies. Is causing burr. Further, since the molten metal Y having a high specific gravity is melted in the molten metal Y poured into the mold by the pouring, buoyancy is generated in the mold, and a gap is generated between the upper mold 1A and the lower mold 2A as described above. Let Although it is impossible to completely eliminate the generation of the gap between the upper mold 1A and the lower mold 2A in such a casting apparatus having mold matching, it is possible to improve the casting quality and reduce the man-hours required for deburring after casting. It is desirable to prevent burrs from occurring, such as reduction.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a casting apparatus capable of preventing the occurrence of burrs by minimizing the gap between the upper mold and the lower mold that occurs during pouring.

[0005]

According to the present invention, in a casting apparatus for pouring molten metal into a mold having an upper mold and a lower mold, a vacuum flask having an upper opening for accommodating the upper mold and the lower mold. , The vacuum flask is separated into an upper chamber and a lower chamber through a filter, the upper chamber is filled with dry sand, the upper mold and the lower mold are placed in the dry sand, reduced pressure The upper part of the flask is closed with a film, and the lower chamber is connected to a vacuum source.

[0006]

Therefore, inside the vacuum flask, the lower chamber is depressurized by the depressurizing source, and the upper chamber is depressurized through the filter. Since the open top of the vacuum flask is closed by the film, the negative pressure is transmitted to the dry sand, and the negative pressure acts evenly on the entire upper and lower molds in the dry sand. To do. At the time of pouring, the gas generated in the mold diffuses in the pressure-reduced vacuum flask,
Combined with the effect of equalizing the pressure applied to the mold, generation of a gap between the upper and lower mold seams is suppressed, and burr is prevented.

[0007]

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

In FIG. 1, a vacuum flask 3 has an opening 3 at the top for accommodating a mold consisting of an upper mold 1 and a lower mold 2.
The upper chamber 3a and the lower chamber 3b are separated by a filter 4 which has a d and through which gas can flow but sand cannot pass. The upper chamber 3a is filled with dry sand 6, and the upper mold 1 and the lower mold 2 are arranged in the dry sand 6. The sprue 7 is led from the mold to the upper opening 3d. An upper opening 3d of the vacuum flask 3 is closed by a film 5, an exhaust port 3c is provided in the lower chamber 3b, and the exhaust port 3c communicates with a vacuum source P.

The decompression source P may be either a vacuum pump or a decompression tank. If necessary, a weight may be placed on the upper mold 1 or a flange may be provided on the upper mold 1 and the lower mold 2 to tighten them, as is well known.

When the pouring work is performed, the lower chamber 3 has the above structure.
When b is decompressed by the decompression source P, the upper chamber 3a is decompressed through the filter 4 and the opening 3d is closed by the film 5, so that the film 5 is exposed to the atmospheric pressure but the dry sand 6 has the negative pressure. Thus, the negative pressure can be uniformly applied to the entire surfaces of the upper mold 1 and the lower mold 2. And
When poured into the sprue 7, the gas generated in the upper mold 1 and the lower mold 2 quickly diffuses into the depressurized flask 3.
Therefore, the effect of equalizing the pressure applied to the mold and the early diffusion of gas are combined to suppress the generation of the gap between the upper and lower molds and prevent the formation of burrs.

[0011]

As described above, according to the present invention, the gap generated at the time of pouring at the joint between the upper mold and the lower mold is suppressed and the generation of burrs is prevented. The accuracy is improved, and the cost required for deburring can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an explanatory view showing a conventional casting mold.

FIG. 3 is an explanatory view showing another conventional casting mold.

[Explanation of symbols]

 1, 1A, 1B ··· Upper mold 2, 2A, 2B ··· Lower mold 3 ··· Flask 3a ··· Upper chamber 3b ··· Lower chamber 3c ···・ ・ Exhaust port 3d ・ ・ Opening part 4 ・ ・ ・ ・ ・ ・ ・ Filter 5 ・ ・ ・ ・ ・ Film 6 ・ ・ ・ ・ ・ Sand 7 ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ Decompression source W ・ ・ ・ ・

Claims (1)

[Claims] 1. A casting apparatus for pouring molten metal into a mold consisting of an upper mold and a lower mold, comprising a pressure reducing flask having an upper opening for accommodating the upper mold and the lower mold, and the pressure reducing flask via a filter. Is separated into an upper chamber and a lower chamber, the upper chamber is filled with dry sand, the upper mold and the lower mold are placed in the dry sand, the top of the vacuum flask is closed with a film, the The casting chamber is characterized in that the lower chamber communicates with a decompression source.