JP2024058845A - Die Casting Equipment - Google Patents

Abstract

A die casting device is provided that can more reliably crush solidified pieces and prevent air entrapment defects in products.
[Solution] The die-casting apparatus 100 comprises a sleeve 30 into which molten metal is supplied, dies 10, 20 which form a cavity C, and a runner R which connects the cavity C and the sleeve 30 and guides the molten metal supplied to the sleeve 30 to the cavity C. Within the runner R, there are formed a plurality of protrusions 22 which extend along the direction in which the molten metal flows and are arranged in a comb-tooth pattern in the width direction of the runner R, with the cross-sectional shape perpendicular to the longitudinal direction of the runner R being trapezoidal and the cross-sectional shape parallel to the front of the fixed mold 20 being diamond-shaped.
[Selected figure] Figure 2

Description

The present invention relates to a die casting device.

In a die casting apparatus, the molten metal that comes into contact with the inner surface of the plunger sleeve (hereinafter also simply referred to as the "sleeve") is cooled and solidified, so that a solidified material of the molten metal is generated on the inner surface of the sleeve. The solidified material is peeled off from the inner surface of the sleeve by the plunger tip moving forward inside the sleeve, and becomes a solidified piece (also referred to as an "initial solidified piece"). The solidified piece is then mixed into the cavity of the mold together with the molten metal. This causes a casting defect. Therefore, Patent Document 1 describes that in order to crush the solidified pieces, multiple protrusions are provided in the runner that connects the sleeve and the cavity, which extend along the direction in which the molten metal flows (the longitudinal direction of the runner) and have a triangular cross-sectional shape perpendicular to the longitudinal direction of the runner.

JP 2020-001069 A

However, with the shape of the protrusions in Patent Document 1, there were cases where the solidified pieces slipped through the gaps between adjacent protrusions, making it impossible to crush the solidified pieces. In addition, the molten metal colliding with the protrusions could disrupt the flow of the molten metal, causing air entrapment defects in the product.

The present invention was made to solve these problems, and aims to provide a die-casting machine that can more reliably crush solidified pieces and prevent air entrapment defects in the product.

The die casting apparatus according to a first aspect of the present invention includes a sleeve to which molten metal is supplied,
A mold for forming a cavity;
a runner that communicates the cavity with the sleeve and guides the molten metal supplied to the sleeve to the cavity;
Equipped with
A plurality of protrusions are formed within the runner, extending along the direction in which the molten metal flows and arranged in a comb-tooth pattern in the width direction of the runner, the cross-sectional shape perpendicular to the longitudinal direction of the runner being trapezoidal and the cross-sectional shape parallel to the front surface of the mold being diamond-shaped.

According to the die-casting apparatus of the first aspect of the present invention, a plurality of protrusions are provided on the runner along the direction in which the molten metal flows. In addition, since the cross-sectional shape of the protrusions perpendicular to the longitudinal direction of the runner is trapezoidal, the distance between adjacent protrusions is narrower than when the cross-sectional shape is triangular with the same base length. This makes it possible to prevent the solidified pieces from slipping through between the adjacent protrusions, and to more reliably crush the solidified pieces. Furthermore, the cross-sectional shape of the protrusions parallel to the front surface of the mold is rhombus. In other words, the width of the protrusion gradually becomes thicker along the direction in which the molten metal flows, is maximum at approximately the center, and then gradually becomes thinner. Therefore, even if the molten metal hits the protrusion, it is possible to reduce turbulence in the flow of the molten metal. Therefore, it is possible to provide a die-casting apparatus that can more reliably crush the solidified pieces and prevent air entrainment defects in the product.

1 is a schematic cross-sectional view of a die-casting apparatus 100 according to a first embodiment of the present invention. FIG. 2 is a partial front view of the fixed mold 20 according to the first embodiment of the present invention. 3 is a cross-sectional view taken along line III-III in FIG. 2.

The following describes embodiment 1 of the present invention with reference to the drawings. However, the present invention is not limited to embodiment 1 below. Also, to clarify the explanation, the following description and drawings have been simplified as appropriate.

First Embodiment
<Overall configuration of die casting equipment>
First, the overall configuration of a die casting apparatus 100 according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view of the die casting apparatus 100.
It should be understood that the right-handed xyz Cartesian coordinate system shown in FIG. 1 and other drawings is for the convenience of explaining the positional relationship of the components. Usually, the positive direction of the z axis is vertically upward, and the xy plane is a horizontal plane, which is common among the drawings.

As shown in FIG. 1, the die-casting apparatus 100 according to the first embodiment includes a movable die 10, a fixed die 20, a plunger sleeve 30, and a plunger 40. FIG. 1 shows the state in which molten metal M is supplied to the plunger sleeve 30 in the die-casting apparatus 100.

The movable die 10 is a die that can slide in the x-axis direction. On the other hand, the fixed die 20 is a die that is fixed to the die casting apparatus 100. When the movable die 10 moves in the positive direction of the x-axis and comes into contact with the fixed die 20, a cavity C corresponding to the shape of the product to be cast is formed between the movable die 10 and the fixed die 20, as shown in Fig. 1. Furthermore, a casting is cast by filling this cavity C with molten metal M. Then, the movable die 10 moves in the negative direction of the x-axis and is released from the fixed die 20, whereby the casting can be removed.
The movable die 10 and the fixed die 20 are made of, for example, alloy tool steel for hot work dies. The movable die 10 and the fixed die 20 may each be a nested die.

1, a through hole having a circular cross section and a central axis parallel to the x-axis is formed in the fixed die 20. A cylindrical plunger sleeve 30 is fitted into this through hole. A plunger 40 slides in the x-axis direction inside the plunger sleeve 30.
A runner R is formed on the upper end of the plunger sleeve 30 on the movable mold 10 side (negative x-axis side) between the fixed mold 20 and the movable mold 10, connecting the plunger sleeve 30 to the cavity C and guiding the molten metal M to the cavity C.

The plunger sleeve 30 is a cylindrical member having a central axis parallel to the x-axis. As described above, the plunger sleeve 30 is fitted into the through hole of the fixed die 20. Molten metal M is poured into the plunger sleeve 30. A molten metal supply port 31 for pouring the molten metal M into the plunger sleeve 30 is formed on the upper surface near the rear end (positive x-axis side) of the plunger sleeve 30. The molten metal M is poured into the plunger sleeve 30 from the molten metal supply port 31 using, for example, a ladle (not shown) or the like.
The plunger sleeve 30 is made of, for example, alloy tool steel for hot work dies.

The plunger 40 includes a plunger tip 41 and a plunger rod 42 .
The plunger tip 41 is a cylindrical member that directly contacts the molten metal M in the plunger sleeve 30. The plunger tip 41 is connected to a drive source (not shown) by a plunger rod 42, which is a rod-shaped member having a central axis parallel to the x-axis, and can slide in the x-axis direction inside the plunger sleeve 30. The plunger tip 41 slides from the rear end of the plunger sleeve 30 in the negative x-axis direction, whereby the molten metal M injected into the plunger sleeve 30 is injected into the cavity C.

Here, as described above, when the molten metal M is supplied to the plunger sleeve 30, the molten metal M that comes into contact with the plunger sleeve 30 is cooled and solidified. Therefore, a solidified piece (also referred to as an "initial solidified piece") is formed on the inner surface of the plunger sleeve 30 that comes into contact with the molten metal M. When the plunger tip 41 advances inside the plunger sleeve 30, if this solidified piece peels off from the plunger sleeve 30 and is injected into the cavity C of the mold (movable mold 10, fixed mold 20) together with the molten metal M, it may cause a casting defect.
As will be described below, in the die casting apparatus 100 according to the first embodiment, the runner R is provided with protrusions for reducing casting defects caused by solidified pieces.

<Configuration of runner in mold>
Next, the configuration of the runner R that communicates between the plunger sleeve 30 and the cavity C of the mold (movable mold 10, fixed mold 20) in the die casting apparatus 100 according to the first embodiment will be described with reference to Figures 2 and 3. Figure 2 is a partial front view of the fixed mold 20. Figure 3 is a cross-sectional view taken along the line III-III in Figure 2. Figure 3 also illustrates the movable mold 10. In the example shown in Figures 2 and 3, the groove-shaped runner R is formed in the fixed mold 20 and the plunger sleeve 30, but it may be formed in the movable mold 10, or may be formed in both the movable mold 10 and the fixed mold 20.

As shown in Figures 2 and 3, a groove-shaped runner R is formed on the end face of the plunger sleeve 30 and the front face of the fixed mold 20 to guide the injected molten metal M to the cavity C. The runner R extends from the inner peripheral surface of the plunger sleeve 30 to the cavity C. A number of protrusions 22 extend along the longitudinal direction of the runner R, i.e., along the direction in which the molten metal M flows (the positive direction of the z-axis in the example of Figure 2). The protrusions 22 are also arranged in a comb-like pattern in the width direction of the runner R. In the example shown in the figure, seven protrusions 22 are provided.

In addition, the cross-sectional shape of the protrusion 22 perpendicular to the longitudinal direction of the runner R (cross-sectional shape parallel to the x-y plane) is trapezoidal. As a result, the width of the protrusion 22 (length in the y-axis direction), i.e., the width of the trapezoid shape of the protrusion 22, gradually thickens from the top side to the base side. Therefore, the distance between adjacent protrusions 22 is narrower than when the base sides are the same length and the cross-sectional shape perpendicular to the longitudinal direction is triangular. This makes it possible to prevent the solidified pieces from slipping through between adjacent protrusions 22, and allows the solidified pieces to be crushed more reliably. In other words, the initial solidified pieces can be crushed into solidified pieces of a size that does not cause manufacturing defects.

Furthermore, the cross-sectional shape (cross-sectional shape parallel to the y-z plane) of the protrusion 22 parallel to the front surface of the die (fixed die 20 in the examples of Figures 2 and 3) has a rhombus shape with rounded corners. As a result, the width of the protrusion 22, i.e., the width of the trapezoidal shape of the protrusion 22, gradually becomes thicker along the direction in which the molten metal M flows, becomes maximum at approximately the center, and then gradually becomes thinner. In addition, since the corners of the rhombus are rounded, the shape of the protrusion 22 is streamlined. Therefore, even if the molten metal M hits the protrusion 22, it is possible to reduce turbulence in the flow of the molten metal.
Specifically, if the cross-sectional shape of the protrusion parallel to the front surface is rectangular, the surface of the protrusion on the upstream side in the direction in which the molten metal M flows will be flat, and the molten metal M will collide with this flat surface, causing turbulence in the flow of the molten metal M. Furthermore, if the cross-sectional shape of the protrusion perpendicular to the longitudinal direction is made trapezoidal in order to narrow the space between adjacent protrusions, the area of the flat surface will become large, and the possibility of turbulence in the flow of the molten metal M will increase.
In contrast, since the cross-sectional shape of the protrusion 22 parallel to the front surface according to the first embodiment is a diamond shape, the width of the protrusion 22 gradually becomes thicker along the direction in which the molten metal M flows, becomes maximum at approximately the center, and gradually becomes thinner. Therefore, the surface on the upstream side in the direction in which the molten metal M flows of the protrusion 22 is narrower than the cross-sectional shape parallel to the front surface of the longitudinal center of the protrusion 22. Therefore, it is possible to reduce the occurrence of turbulence in the flow of the molten metal M caused by the molten metal M colliding with the upstream surface of the protrusion 22. In addition, the width of the protrusion 22 becomes thinner toward the downstream side in the direction in which the molten metal M flows. As a result, the flow rate of the molten metal M flowing between the adjacent protrusions 22 at the longitudinal center of the protrusions 22 decreases compared to the upstream side, but then increases toward the downstream side. Therefore, it is also possible to prevent turbulence in the flow of the molten metal M downstream of the protrusion 22.
Furthermore, the cross-sectional shape of the projection 22 according to the first embodiment, which is parallel to the front surface, has rounded corners. That is, the surface of the projection 22 on the upstream side in the direction in which the molten metal M flows is a curved surface that protrudes toward the molten metal flow, so that it is possible to more effectively prevent the flow of the molten metal M from being disturbed.

In the example shown in FIG. 3, each vertex of the upper side of the protrusion 22, which has a trapezoidal cross section, has an acute angle, but it may also have a rounded shape.

Here, the length of the projection 22 extending along the direction in which the molten metal M flows, i.e., the length of the projection 22 (length in the z-axis direction) is greater than the maximum width of the projection 22 (maximum length in the y-axis direction). Therefore, even if the projection 22 is repeatedly pressed against the molten metal M at high pressure, it is less likely to be damaged than, for example, a cylindrical projection, and the durability of the mold (fixed mold 20 in the examples of Figures 2 and 3) is excellent. For example, it is preferable that the length of the projection 22 is at least twice the maximum width of the projection 22, or at least 1/2 the height (length in the x-axis direction).

In order to reduce casting defects caused by solidified pieces, the higher the height of the protrusion 22, the better. For example, it is preferable that the height of the protrusion 22 is 80% or more of the depth of the runner R, and even more preferably 90% or more. Therefore, as shown in FIG. 3, it is most preferable that the height of the protrusion 22 is equal to the depth of the runner R, but this is not limited to this. Note that the height of the protrusion 22 being equal to the depth of the runner R does not only mean that it is completely equal, but also includes being approximately the same.

As shown in Figures 2 and 3, all the protrusions 22 are formed on the nested portion 23. In other words, all the protrusions 22 are formed integrally with the nested portion 23 at their bases. The nested portion 23 is then fitted into and fixed to the fixed mold 20. That is, the protrusions 22 are provided on the replaceable nested portion 23. Therefore, if the protrusion 22 is damaged, only the nested portion 23 having the protrusion 22 can be replaced, which provides excellent maintainability. Of course, the protrusions 22 may be formed integrally with the fixed mold 20 or the movable mold 10.

As described above, in the die-casting apparatus 100 according to the first embodiment, a plurality of protrusions 22 are provided on the runner R along the direction in which the molten metal M flows. In addition, since the cross-sectional shape of the protrusions 22 perpendicular to the longitudinal direction of the runner R is trapezoidal, the distance between adjacent protrusions 22 is narrower than when the cross-sectional shape is triangular with the same base length. This makes it possible to prevent the solidified pieces from slipping through between the adjacent protrusions 22, and to more reliably crush the solidified pieces. Furthermore, the cross-sectional shape of the protrusions 22 parallel to the front surface of the fixed mold 20 is rhombus. In other words, the width of the protrusions 22 gradually becomes thicker along the direction in which the molten metal M flows, is maximum at approximately the center, and then gradually becomes thinner. Therefore, even if the molten metal M hits the protrusions 22, it is possible to reduce turbulence in the flow of the molten metal. Therefore, it is possible to provide a die-casting apparatus 100 that can more reliably crush the solidified pieces and prevent air entrainment defects in the product.

The present invention is not limited to the above embodiment, and can be modified as appropriate without departing from the spirit and scope of the invention.

REFERENCE SIGNS LIST 10 Movable mold 20 Fixed mold 22 Protrusion 23 Insert portion 30 Plunger sleeve 31 Feed port 40 Plunger 41 Plunger tip 42 Plunger rod 50 Casting 51 Product portion 52 Runner portion 53 Biscuit portion C Cavity M Molten metal R Runner

Claims (1)

a sleeve to which molten metal is supplied;
A mold for forming a cavity;
a runner that communicates the cavity with the sleeve and guides the molten metal supplied to the sleeve to the cavity;
Equipped with
A plurality of protrusions are formed in the runner, the protrusions extending along the direction in which the molten metal flows and arranged in a comb-like shape in the width direction of the runner, the protrusions having a trapezoidal cross-sectional shape perpendicular to the longitudinal direction of the runner and a diamond cross-sectional shape parallel to the front surface of the die.
Die casting equipment.

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