JPS60196246A - Production of casting mold - Google Patents

Abstract

PURPOSE:To eliminate the deformation and wave to be generated in the parts of a casting corresponding to connecting parts with respect to a casting mold having the plural connecting parts between an outside peripheral part and an inside part spaced from each other by providing >=2 notches to the outside peripheral part and performing casting. CONSTITUTION:A core having >=2 connecting parts 3 between an outside peripheral part 1 continuous into one body and inside parts 2 provided at intervals on the inside thereof is formed and is set between a cope 10 and a drag 11. A molten metal is poured through a sprue 14, a runner 16 and a gate 16 into cavities 5, 6, 7, 8. The core is formed in this stage by providing >=2 notches 4 to the part 1 to eliminate the deformation and wrinkle to be generated in the parts of the casting corresponding to the parts 3. The production of the desired casting having no defects is thus made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a casting. More specifically, the present invention relates to a method for manufacturing defect-free castings using a mold having a specific shape.

Currently, castings of various shapes are being manufactured, and therefore the shapes of molds corresponding to these molds also vary widely.

Such molds are produced by curing molding sand containing a gas-curing binder such as furan resin, water glass, or urethane resin using a gas such as carbon dioxide gas, amine gas, or sulfur dioxide gas (gas curing method). However, in this method, the molding sand does not harden at all until gas is blown into it, so it is useful for manufacturing molds with complex shapes that require a long time to mold. Since the foundry sand hardens and the desired mold can be obtained in a short time, it is particularly advantageous for mass production of relatively small molds.

The present inventor has manufactured various castings using molds made of hardened foundry sand, and as shown in FIG. When manufacturing a casting by pouring into a mold having a shape that has an inner part 2 installed at a distance from part 1, and two or more connecting parts 5 that connect these outer peripheral parts and the inner part, I have often experienced deformation or waviness in the part of the casting corresponding to the connecting portion 5, resulting in the casting being defective. It is presumed that this is because the connecting portion 5 is deformed due to some factor during pouring or during the cooling process after pouring, which leads to deformation or waviness of the casting. Therefore, the present inventor conducted various comparative studies on manufacturing a casting that does not cause deformation or waviness in the part of the casting that corresponds to the connecting portion 3. The present invention has been made based on the findings obtained from these comparative studies.

That is, as shown in FIG. 1, the present invention comprises: an outer peripheral part 1 forming a continuous integral part; an inner part 2 disposed inside the outer peripheral part with a distance from the outer peripheral part 1; When manufacturing a casting by pouring metal into a mold having two or more connecting parts 5 connecting the outer peripheral part and the inner part, two or more notches 4 are provided in the outer peripheral part. The method of the present invention will be described with reference to the embodiment shown in FIG. 2. In FIG.
A mold with a specific shape consisting of an inner part (inner block) 2 and a connecting part 3 is used as a core, and has an upper mold 1o and a lower mold 1o.
o and placed on the surface plate 12. 13 is the metal frame, 14 is the sprue, 15 is the runner, 16 is the weir, and 5
,6. , 7 and 8 are cavities, and the molten metal enters the tile from the runner 15 to form a product. Outer periphery 1 of this core
If the notch 4 is provided as shown in FIG. 1, the part of the casting corresponding to the connecting part 5 will not be deformed.

The castings obtained with the mold shown in FIG. 2 are used as disc brake parts for automobiles.

In the present invention, the effect is produced by providing two or more cutouts on the outer periphery of the mold having the shape shown in Fig. 1, but a more detailed study revealed that the It was found that the effect was even greater. That is: (1) When the depth of the notch is greater than or equal to the thickness of the entire outer periphery, preferably % or more, (2) When the planar shape of the outer periphery is circular or oval, especially the outer periphery 1 in Figure 1. The outer edge 1a and the inner R1b are also circular or oval (i.e., the whole is circular or oval)
(3) The vertical cross-sectional area of any part of the outer periphery (meaning the entire cross-sectional area when cut along line A-A in Figure 1) is the vertical cross-sectional area of any part of the connecting part. (B-B' in Figure 1
If the total cross-sectional area (meaning the total cross-sectional area when cut along the line) is also large, then .

In carrying out the present invention, there are no particular limitations on the shapes of the inner portion 2 and the connecting portion 5, and the connecting portion 5 may include two or more polygons.
t can be provided.

Although there is no particular restriction on the shape of the notch 4, providing a wedge-shaped notch is the simplest shape. The number of notches may be two or more, and increases as the number of connecting parts 5 increases, but the number may be the same as the number of connecting parts or smaller than that. Actually, about 2 to 16 pieces may be sufficient. The notches are preferably placed inward along the outer edge of the outer periphery so that the notches are evenly spaced. It is better to avoid this. Fig. 5 shows a state in which the notch 4 and the connecting portion 5 overlap.

The present invention will be described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Example Fig. 2 shows a vertical cross-sectional view, and a continuous type was used, and molten iron (F
e12) was cast to produce a casting. FIG. 4 is a plan view of the mold of the present invention used for the core, and the outer circumferential portion 1 is circular with an outer diameter of 345 m and a width of 22 m5. Thickness is 42M@
, the cross-sectional area is 924 m2, the diameter of the inner part 2 is j90111, the thickness is 46 m2, a total of 36 connecting parts 3 are provided at equal intervals, and the width of the connecting end with the outer peripheral part 1 is 20 m11. inner part 2
The width of the connecting end is 101 m, the cross-sectional shape is oval, and the cross-sectional area is approximately 100 yen2 at the minimum and approximately 20 Q II at the maximum.
2. The number of notches 4 is eight, and they are provided on the outer circumference of the outer circumferential portion 1 at approximately equal intervals and so as not to overlap with the connecting portion 5.

The notch 4 had a wedge-shaped planar shape, and the distance between its tip and the inner edge 1b of the outer circumference was 12,111. The obtained casting had no deformation at all in the portion corresponding to the connecting portion 3 and was free from defects.

Comparative Example A casting was produced in the same manner using a mold in which notch 4 was not inserted at all. Deformation occurred in 16 of the parts (36 in total) corresponding to the connecting part 5, resulting in defective castings.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of the shape of the mold used in the present invention, Fig. 2 is a schematic vertical sectional view showing the state during manufacturing of castings, and Fig. 3 is a partial perspective view of the mold illustrating the arrangement of notches. , FIG. 4 is a plan view of the mold of the present invention. 1... Outer circumferential part 2... Inner part 3... Connecting part 4... Notch Applicant Kaoru Furuya Figure 1 Figure 2 Figure 3 Diagram Figure 4

Claims (1)

[Claims] 1. A continuous outer peripheral part, an inner part provided inside the outer peripheral part at intervals, and two or more connecting parts connecting the outer peripheral part and the inner part. 1. A method for producing a casting, characterized in that two or more notches are provided in the outer periphery of the casting when the casting is produced by pouring into a mold having a mold. 2. A notch is provided inward from the outer edge of the outer periphery,
The method for manufacturing a casting according to claim 1, wherein the depth is at least % of the thickness of the outer peripheral portion. B. The method for manufacturing a casting according to claim 1 or 2, wherein the planar shape of the outer periphery of the mold is circular or oval. 4. Manufacturing a casting according to any one of claims 1 to 5, wherein the vertical cross-sectional area of any part of the outer periphery of the mold is larger than the vertical cross-sectional area of any part of the connecting part. Method.