JPH0588742U - Casting mold - Google Patents

Abstract

(57) [Summary] [Purpose] To eliminate the effect of cracks on burrs on cast products. A cavity 3 is formed in one of the matching dies 1 and 2, and a shallow strip-shaped recess 5 is formed on the parting surface 4 of the other die 2 so as to surround the outer edge of the cavity 3. The molds 1 and 2 form thin crack protection overhangs on the mold parting line of the casting, and the cracks generated in the burr are suppressed by the protection overhangs to protect the casting.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a mold for casting, and more particularly, to a mold for casting in which a crack generated in a burr does not adversely affect a cast product.

[0002]

[Prior Art]

 A burr formed by the molten metal leaked to the mating portion of the mold is formed on the outer peripheral edge of the cast product molded using the mating mold.

This kind of burr is generally very thin and solidifies faster than other parts, so that this part is brittle and easily cracked. Moreover, as shown in FIG. 5 (a), the inner edge of the crack c may often enter from the peripheral portion of the cast product W to the inside of the main body. When it comes into contact with another object or when a strong force acts on this part during the deburring process, the burr b near the crack c takes in a part e of the main body as shown in Fig. 2 (b). This causes problems such as chipping off and ruining the cast product.

[0004]

[Problems to be solved by the device]

 The present invention has been made in view of such a problem, and an object of the present invention is to provide a new casting mold for forming a cast product which is not affected by cracks generated in burrs. ..

[0005]

[Means for Solving the Problems]

 That is, the present invention, as a casting mold for achieving such a subject, is formed in a burr by surrounding at least a part of the outer edge of a cavity formed corresponding to the shape of the casting on the joining surface of the mold. A shallow band-shaped recess for crack protection is formed with a width that does not reach the main body of the cast product, and a crack protection overhang part is formed on the mold parting line of the cast product. It is designed to eliminate the effects of cracks.

[0006]

【Example】

 Therefore, the embodiment illustrated below will be described. FIG. 1 shows an example of a mold to which the present invention is applied.

In the figure, reference numerals 1 and 2 are a pair of molds to be joined, and a cavity 3 corresponding to the shape of a cast product W to be molded is formed in one of the molds 1, and the other mold is joined. On the parting surface 4 of the mold 2, a shallow band-shaped recess 5 is formed so as to surround the outer edge of the cavity 3.

The recess 5 is for forming an overhanging portion f for crack protection on the mold parting line of the cast product W. The width d of the recess 5 is such that the inner end of the burr b is the width of the cast product W. It is necessary that the width is such that it does not reach the main body, and that the depth t is preferably slightly larger than the thickness of the burr b. Reference numeral 7 in the drawing indicates a nest for forming the central circular hole h of the cast product W.

The pair of molds 1 and 2 formed in this way are joined, the molten metal is injected into the cavity 3 formed inside, and after waiting for the surface to solidify, the cast product W is formed from these molds 1 and 2. When taken out, as shown in FIG. 2, in the cast product W, an overhanging portion f for crack protection having a wall thickness t slightly larger than the thickness of the burr b is formed along the mold dividing line. A burr b formed by the leaked molten metal is formed on the outside thereof.

Therefore, even if a crack c occurs in the burr b portion, the inner end of the crack c stops at the crack protection overhanging portion f, so that the burr in this portion is chipped off. However, there is no influence on the body of the cast product W. Further, since this crack protection overhang f is formed thinly, it can be easily removed in the deburring step after release.

FIG. 3 shows another embodiment of the present invention applied to a knuckle arm molding die. In the fixed mold and the movable mold for gravity casting shown by reference numerals 11 and 12 in the figure, the cavity 13 corresponding to the shape of the knuckle arm is formed, and the molten metal injected from the sprue is not shown It is configured to flow in from the lower end of the cavity 13 via a road.

The movable mold 2 is provided with an insert 16 for forming an axial hole and a core pin insert 17, and further, at the root part of the core pin insert 17, that is, on the parting surface 14 on the fixed mold 1 side. A shallow recess 15 for forming a crack protection overhang f is formed so as to surround the outer edge.

Therefore, as shown in FIG. 4, the knuckle arm W 1 formed by these mating dies 11 and 12 has an overhanging portion f for crack protection formed on the die parting line at its end. Therefore, it is possible to prevent damage to the body of the cast product W due to cracks generated in the burr.

In the above description, the concave portion forming the overhanging portion f for crack protection is provided on one parting surface of the mold, but this concave portion is formed on each parting surface of the pair of molds. May be provided.

[0015]

[Effect of the device]

 As described above, according to the present invention, since the shallow band-shaped recess is formed on the die joint surface so as to surround the outer edge of the cavity, crack protection is not provided on the die parting line of the formed casting. The burrs will be formed through the overhanging part for the cracks, and even if cracks occur in the burrs, it is possible to prevent these cracks from reaching the body of the casting, Even if the burr is chipped off, the crack protection overhang can completely eliminate the effect on the cast body.

Moreover, since the crack protection overhanging portion formed by the shallow recess is extremely thin, it can be removed without burdening the deburring work after release from the mold.

[Brief description of drawings]

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

2 (a) and 2 (b) are a plan view and a sectional view of a cast product formed by the same mold.

FIG. 3 is a sectional view of a mold showing another embodiment of the present invention.

FIG. 4 is a plan view of a cast product formed by the same mold.

5 (a) and 5 (b) are a plan view and a sectional view showing an example of a cast product formed by a conventional mold.

[Explanation of symbols]

 1, 2, 11, 12 Mold 3, 13 Cavity 4, 14 Parting surface 5, 15 Shallow band recess W Casting f Crack protection overhang b Burr c Crack

Claims (1)

[Scope of utility model registration request] 1. A width to such an extent that an inner end of a crack generated in a burr does not reach a main body of a cast product by surrounding at least a part of an outer edge of a cavity formed corresponding to a shape of the cast product on a joint surface of a mold. A mold for casting, characterized in that a shallow band-shaped concave portion having a crack is formed.