JPH06154986A - Die casting product - Google Patents

Abstract

PURPOSE:To reduce working time and cost owing to the unnecessitating of cutting of burrs by making gate cross sectional shape in an aluminum die casting product small in the vicinity of the boundary part of the product, and generating the stress concentration, thereby making the burrs at the gate trace part small. CONSTITUTION:By making at least one side of the width or the thickness in the cross sectional shape of a sprue or an overflow gate 2 near the boundary part of the aluminum die casting product 3 smaller than the sprue or the overflow body 1, or the other part of the sprue or the overflow gate 2, the stress concentration is generated in the vicinity of the boundary part of the aluminum die casting product 3 and the burrs shape at the gate trace part is made small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die-cast product, and more particularly to a gate portion shape suitable for eliminating burr-free cutting of gate marks. Hereinafter, aluminum die cast products will be described as a typical example.

[0002]

2. Description of the Related Art As to aluminum die cast products, as described in JP-A-62-45974, the mold structure is simple,
There is described a structure having a structure for preventing formation of cavities during post-processing in order to improve accuracy without impairing the sealing effect.

[0003]

The above-mentioned prior art does not consider the burr shape and non-cutting of aluminum die cast products. That is, depending on the burr shape of the gate mark, interference with surrounding parts, deterioration of assembly workability due to interference,
Also, a problem such as injury is caused to the assembly worker. In order to prevent this, it is necessary to perform deburring work on the traces of the gate, which causes a problem of increased work time and cost.

An object of the present invention is to solve the above-mentioned problems and to provide an aluminum die-cast product which is low in cost and does not burden the assembly operator.

[0005]

The above object can be achieved by the following. That is, in aluminum die cast products,
The cross-sectional shape of the sprue or overflow gate in the vicinity of the boundary between the product and the sprue or overflow has at least one of width and thickness smaller than that of the sprue or overflow body or other portions of the overflow gate. In addition to the above, the cross-sectional shape of the sprue or overflow gate is arbitrarily increased stepwise from the product boundary surface. Moreover, the boundary portion of the cross section is rounded or rounded. Alternatively, it is increased substantially in proportion to the distance from the product boundary surface. Alternatively, one notch is provided in the vicinity of the product boundary portion, or two notches are provided symmetrically about the gate or the overflow gate, or several places are provided on the circumference. Alternatively, by providing the spout or overflow gate with fins having an arbitrary angle with respect to the aluminum die cast product.

[0006]

With the above structure, stress concentration occurs near the boundary between the product and the sprue or overflow gate, and the position of the cut portion can be brought closer to the boundary surface. Also, if the gate or overflow gate cross-sectional shape cannot be reduced near the boundary with the product due to the structure, it is possible to obtain the same effect as the above by gradually reducing the cross-section as it approaches the product boundary. Become. Also,
By increasing the sprue or overflow gate approximately in proportion to the distance from the product boundary surface, stress concentration occurs near the product boundary portion and the burr surface roughness of the gate trace can be reduced in the same manner as above. . Also, by providing one notch in the product boundary surface, two notches symmetrically with respect to the axis, or several notches on the circumference, it is possible to obtain the same effects as the above such as stress concentration. Moreover, by providing the notch portion perpendicular to the cutting direction, it is possible to reduce the size of the notch having the same shape provided in the other direction. Further, by providing fins having an arbitrary angle with respect to the sprue or the overflow gate, it becomes possible to increase the velocity component of the melt flow in the centrifugal direction.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1, a sprue or overflow body 1 is connected to an aluminum die cast product by a sprue or overflow gate 2. In contrast to (b), the drawing of (a) shows a shape incorporating the present invention, and the cross-sectional shape of the sprue or overflow gate near the boundary between the aluminum die-cast product and the sprue or overflow gate is defined by at least the width or the thickness. By making either one smaller than the sprue or overflow body, or the other part of the sprue or overflow gate, it becomes possible to cause stress concentration in the cross section, and it becomes possible to cut more in the vicinity of the product. The change in the cross-sectional shape near the boundary changes the flow of the molten metal, which causes problems such as the formation of nests due to the entrainment of air. However, the flow of molten metal at the spout or overflow body 1 and at the spout or overflow gate 2 It is possible to prevent the influence of the change of the cross-sectional shape on the molten metal flow in the aluminum die cast product 3 by changing the speed of.

FIG. 2 shows another embodiment, in which (1)
In, the cross-sectional shape of the sprue or overflow gate 2 is increased stepwise at an arbitrary distance from the aluminum die cast product 3. As a result, the effects as described above can be obtained without being affected by the ambient conditions and the like.
In addition, it is possible to improve the molten metal flow by rounding or rounding the boundary portion of the cross section, and prevent deterioration of the molten metal flow due to changes in the cross section of the sprue and the overflow gate.

In (2), fins having an arbitrary angle with respect to the aluminum die-cast product 3 are provided on the sprue and the overflow gate 2 so that the flow component of the hot water is increased in the centrifugal direction and the flow component is directed in the direction of this flow component. By reducing the cross-sectional shape of the sprue or overflow gate 2 in the vicinity of the aluminum die-cast product, deterioration of the molten metal flow can be prevented as in the above case, and cutting can be performed in the vicinity of the aluminum die-cast product.

FIG. 3 shows another embodiment. In (3), the cross-sectional shape of the sprue or overflow gate 2 is increased substantially in proportion to the distance from the boundary surface of the aluminum die-cast product 3, whereby Similarly, stress concentration can be caused in the vicinity of the boundary portion of the aluminum die-cast product 3, and due to the inclination of the sprue and the overflow gate 2, the gate trace portion is different from the case where only the sprue and overflow gate 2 or the straight portion is provided. It is possible to reduce the surface roughness of the burr.

In (4), by providing a notch in the gate or overflow gate 2 in one direction on the boundary surface of the aluminum die-cast product 3, the effect of stress concentration and the roughness of the burr surface of the gate mark portion can be obtained as in the above case. Can be made smaller. Also, by providing a notch only in one direction,
There is no fear of deteriorating the flow of hot water. Also, in the case of notches with the same shape, bending makes it possible to generate a larger stress concentration with respect to twisting, so by providing the notches in the direction perpendicular to the cut surface, the notch shape Can be made smaller, and it becomes easy to prevent deterioration of hot water flow due to notches. Further, the decrease in stress concentration due to the addition of the notches becomes smaller as the gap between the notches becomes smaller. However, even if the notch is formed in a small size all around, stress concentration always occurs. Therefore, the burr surface roughness of the gate trace can be further reduced by providing the notches at two locations in the axial direction of the sprue or overflow gate 2, or at several locations on the circumference, or on the entire circumference. In addition, since the cutout shape is effective with the minimum size, it is possible to prevent the deterioration of the hot water flow as described above.

[0012]

EFFECTS OF THE INVENTION According to the present invention, stress concentration is caused in the vicinity of the boundary between the sprue or overflow gate and the aluminum die-cast product, whereby cutting can be performed in the vicinity of the product, and by providing a notch or the like. It is possible to reduce the roughness of the burr surface on the traces of the gate. As a result, it is possible to prevent interference between burrs and surrounding parts, deterioration of assembly workability, injury of an assembly worker, and the like, and it is possible to reduce costs due to elimination of deburring work.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a gate shape of an aluminum die cast product according to the present invention.

2 (1) and (2) are vertical cross-sectional views showing another embodiment.

3 (3) and (4) are longitudinal sectional views showing another embodiment.

[Explanation of symbols]

1 ... gate and overflow body, 2 ... gate and overflow gate, 3 ... aluminum die cast product.

Claims (6)

[Claims] 1. A die-cast product having a width or a thickness so that the cross-sectional shape of the sprue or overflow gate near the boundary between the sprue and the overflow or the overflow has a strength difference at the boundary between the sprue or overflow body and the product. A die-cast product, characterized in that at least one of them is made smaller than the sprue, the overflow body, or other parts of the overflow gate. 2. The die cast product according to claim 1, wherein the shape of the sprue or overflow gate has a strength difference within a range of 2 mm from the product boundary. 3. The die-cast product according to claim 1, wherein the cross-sectional area of the sprue or overflow gate is gradually increased from the product boundary surface. 4. The die-cast product according to claim 1, wherein the cross-sectional area of the sprue or the overflow gate is increased substantially in proportion to the distance from the product boundary surface. 5. A notch according to claim 1, wherein notches are provided at a boundary portion between the sprue or overflow gate and the product, at one location, at two locations in axial symmetry, at several locations on the circumference, or at the entire circumference. Die casting product. 6. The die-cast product according to claim 1, wherein the sprue or overflow gate is provided with fins having an arbitrary angle with respect to the product.