KR20230078446A - Die casting device - Google Patents

Abstract

One embodiment of the present invention provides a pressure casting device, comprising: a mold configured to include an upper mold provided with a pinhole, a lower mold, and a cavity formed by combining the upper mold and the lower mold; a core disposed inside the cavity; and an eject part configured to include a hollow pin guide inserted into the pinhole, a hollow sleeve vent inserted into the pin guide and formed to form a predetermined gap with the inner peripheral surface of the pin guide, and an eject pin inserted into the sleeve vent. Thus, the present invention can provide the pressure casting device that can improve an appearance quality of hollow-shaped castings by pressure casting.

Description

Pressure casting device {DIE CASTING DEVICE}

The present invention relates to a pressure casting apparatus.

Pressure casting is a method of pressurizing and injecting molten metal into the molding space of a mold in which a cast product is formed, and solidifying it. When the pressure gas is filled, the molten metal in the melting furnace is injected into the molding space of the mold by the filled gas pressure to fill the molding space of the mold.

Pressure casting has advantages such as high productivity, high dimensional accuracy, beautiful casting surface, and thin casting, and is widely used from many types of automobile parts to electric parts and daily necessities.

On the other hand, automobile parts having a structure in which a hollow is formed are manufactured by inserting a separate core for forming a hollow product into a mold and then injecting molten metal made by melting metal into the mold.

When molten metal is injected into a mold and molded, gas is generated due to combustion of the core yarn due to contact between the core and the molten metal. Specifically, Figure 1 shows a cast product cast by a pressure casting mold according to the prior art. As shown in FIG. There was a problem with being bad.

In addition, when hollow automobile parts are manufactured by applying a pressure casting method, there is a problem that the core yarn erodes the surface of the product. In particular, in the case of hollow automobile parts made of aluminum, there is a problem that the appearance quality is severely deteriorated due to erosion of the core yarn, such as poor processing, cleanliness and roughness.

Accordingly, hollow automobile parts are mainly using a gravity casting method in which molten metal is injected into a mold using the gravity of the molten metal itself.

The present invention is to solve the problems of the prior art, and an object of the present invention is to provide a pressure casting apparatus capable of improving the appearance quality of a hollow cast product by pressure casting.

One aspect of the present invention is a mold configured to include an upper mold, a lower mold having a pinhole, and a cavity formed by combining the upper mold and the lower mold, a core disposed inside the cavity, and a hollow pin guide inserted into the pinhole, A hollow sleeve bent inserted into the pin guide and formed to form a predetermined gap with the inner circumferential surface of the pin guide, and an ejection unit configured to include an eject pin inserted into the sleeve vent. .

In one embodiment, a coating layer may be formed on the outside of the death penalty.

In one embodiment, a plurality of vent holes pass through the upper mold, and at least one of a sinter vent and a slit vent for discharging gas may be disposed in the vent hole.

In one embodiment, a plurality of cut surfaces extending in the axial direction of the sleeve vent may be formed around an outer circumferential surface of the sleeve vent, and a first vertical passage may be formed between the cut surface and the inner circumferential surface of the pin guide. there is.

In one embodiment, the cutting surface may be arranged to form an equal distance from the adjacent cutting surface.

In one embodiment, a second vertical passage may be formed between the eject pin and the inner circumferential surface of the sleeve vent.

In one embodiment, a plurality of horizontal passages extending horizontally from the cavity to the outside of the mold may be formed in the mold.

In one embodiment, an inner gap on the cavity side of the horizontal passage may be larger than an outer gap on the outer side of the mold.

According to one aspect of the present invention, since the gas generated by the core inside the mold is simultaneously discharged to the outside of the mold through the first vertical passage, the second vertical passage, the sintering vent, the slit vent, and the horizontal passage, pressure casting The appearance quality of castings can be improved.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

1 shows a casting product cast by a pressure casting apparatus according to the prior art.
2 is a perspective view of a pressure casting apparatus according to an embodiment of the present invention.
3 is an exploded perspective view of a pressure casting apparatus according to an embodiment of the present invention.
4 is a plan view of an upper mold according to an embodiment of the present invention.
5 is a plan view and a cross-sectional view schematically showing a first vertical passage and a second vertical passage according to an embodiment of the present invention.
6 is a schematic cross-sectional view of a horizontal flow path according to an embodiment of the present invention.
7 shows a casting product cast by a pressure casting apparatus according to an embodiment of the present invention.
8 shows the inner surface of an aluminum casting product according to an embodiment of the present invention and a comparative example.
9 is an SEM image of the surface microstructure of cores according to an embodiment of the present invention and a comparative example.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and, therefore, is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected" but also the case where it is "indirectly connected" with another member interposed therebetween. . In addition, when a part "includes" a certain component, it means that it may further include other components without excluding other components unless otherwise stated.

Terms including ordinal numbers such as 'first' or 'second' used herein may be used to describe various components or steps, but the components or steps should not be limited by ordinal numbers. . Terms containing ordinal numbers should only be construed to distinguish one component or step from other components or steps.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a perspective view of a pressure casting apparatus 1 according to an embodiment of the present invention, and FIG. 3 is an exploded perspective view of the pressure casting apparatus 1 according to an embodiment of the present invention.

As shown in FIGS. 2 and 3 , the pressure casting apparatus 1 according to an embodiment of the present invention is configured to include a mold 100, a core 200, and an ejection unit 300.

The mold 100 is configured to include an upper mold 110 constituting an upper part and a lower mold 120 constituting a lower part, and a cavity 130 having a shape constituting the outline of the casting product C is formed inside the mold 100. It can be.

An injection hole (not shown) may be formed at one side of each of the upper mold 110 and the lower mold 120 to supply molten metal into the cavity 130 .

Inside the cavity 130, a core 200 capable of forming the inner and outer shapes of the hollow cast product C is disposed. The core 200 may be formed in various shapes according to the specific shape of the cast product (C).

4 is a plan view of an upper mold 110 according to an embodiment of the present invention, and FIG. 5 is a plan view schematically showing a first vertical passage V1 and a second vertical passage V2 according to an embodiment of the present invention. And as a cross-sectional view, it is an enlarged view of part A in FIG. 4 .

On the other hand, when molten metal made by melting metal is injected into the mold 100 and molded, gas is generated as the core 200 burns due to contact between the core 200 and the molten metal, thereby generating Appearance quality may deteriorate.

Accordingly, as shown in FIGS. 4 and 5, the pressure casting apparatus 1 according to an embodiment of the present invention smoothly moves the gas generated inside the cavity 130 upward in the vertical direction of the mold 100. It is characterized in that it further comprises vertical flow passages (V1, V2) so that they can be discharged.

In relation to this, on one side of the upper mold 110, a pinhole 112 is formed through which the cavity 130 vertically penetrates to communicate with the outside, and the pinhole 112 includes the pin guide 310, the sleeve vent 320 and the ejector An ejector 300 configured to include a pin 330 is inserted.

Specifically, a pin guide 310 formed in a hollow shape is inserted into the pin hole 112 . The pin guide 310 is formed in a hollow cylindrical shape having a predetermined thickness and adheres to the inner circumferential surface of the pin hole 112 .

A sleeve vent 320 is inserted into the inner circumferential surface 311 of the pin guide 310 . The sleeve vent 320 is formed in a hollow cylindrical shape having a predetermined thickness, and a plurality of cut surfaces 321 extending in the axial direction and composed of flat surfaces are formed along the outer circumference of the sleeve vent 320. . At this time, each cutting surface 321 is arranged to form an equal interval with the adjacent cutting surface 321.

That is, since a plurality of cut surfaces 321 are formed on the outer circumferential surface of the sleeve vent 320, each cut surface 321 is a first vertical passage having a predetermined space together with the inner circumferential surface 311 of the pin guide 310. (V1).

For example, when the number of cut surfaces 321 on the outer circumferential surface of the sleeve vent 320 is 8, the first vertical flow path V1 may be formed at 8 locations, and the gas inside the cavity 130 is the first vertical flow path ( Through V1), it can be discharged upward in the vertical direction of the mold 100.

Preferably, each cut surface 321 may be provided with a plurality of grooves (not shown) extending along the axial direction of the sleeve vent 320 . In this case, since the straightness of the movement of the gas inside the cavity 130 is better, the gas discharge efficiency may be increased.

Preferably, the cut surface 321 may be formed as an inclined surface forming an upward slope from the inside to the outside of the upper mold 110 . In this case, since the first vertical passage V1 is formed such that the gap becomes narrower from the inside to the outside of the upper mold 110, the gas is converted to a fast flow rate while passing through the first vertical passage V1, thereby discharging the gas. Efficiency can be further increased.

An ejection pin 330 is disposed on the inner circumferential surface of the sleeve vent 320 to take out the finished cast product C from the mold 100 driven by the ejection plate. The eject pin 330 is formed at both ends of the body portion 331 extending to have a predetermined length along the axial direction of the sleeve vent 320 and each end along the length direction of the body portion 331, and protrudes in the radial direction. It may include ends 332 and 333 .

Here, each of the ends 332 and 333 is formed to have a diameter close to the inner circumferential surface of the sleeve vent 320, and a second vertical passage V2 is formed between the sleeve vent 320 and the eject pin 330. .

The cross-sectional shape of the ends 332 and 333 may be circular, but is not limited thereto, and polygons such as hexagon, octagon, or hexadecimal may be applied.

That is, gas inside the cavity 130 may be discharged upward in the vertical direction of the mold 100 through the second vertical passage V2.

Preferably, a plurality of grooves (not shown) may be provided on the inner circumferential surface of the sleeve vent 320 to extend along the axial direction. In this case, since the straightness of the movement of the gas inside the cavity 130 is better, the gas discharge efficiency may be increased.

In addition, a plurality of vent holes 113 penetrating in the vertical direction may be formed on one side of the upper mold 110 where the gas is concentrated, and the gas inside the cavity 130 is discharged to the outside in the vent hole 113 to facilitate casting. A sintering vent (not shown) or a slit vent (not shown) may be disposed so as to be stably made. For example, the sintering vent is composed of a cylindrical body having a plurality of micro through holes, and the slit vent is composed of a cylindrical body having a plurality of micro slits.

6 is a schematic cross-sectional view of a horizontal passage H according to an embodiment of the present invention, and is an enlarged view of part B of FIG. 4 .

As shown in FIG. 6, in the pressure casting apparatus 1 according to an embodiment of the present invention, the gas generated inside the cavity 130 can be smoothly discharged along the horizontal direction of the mold 100, It is characterized in that it further comprises a horizontal flow path (H).

The horizontal passage H is formed to communicate horizontally from the cavity 130 to the outside of the mold 100 when the upper mold 110 and the lower mold 120 are molded together.

Specifically, the line is in surface contact with each other and is depressed by a predetermined depth in the upper circumferential surface 111 of the upper mold 110 or the lower circumferential surface 121 of the lower mold 120 formed around the cavity 130. Grooves 114 and 115 are formed. Accordingly, when the upper mold 110 is combined with the lower mold 120, a horizontal flow path H is formed in horizontal communication from the cavity 130 to the outside of the mold 100.

Preferably, in order to prevent the molten metal filled in the cavity 130 from flowing out through the horizontal passage H, the inner gap g1 located on the cavity 130 side of the horizontal passage H is formed on the outside of the mold. It may be formed to be larger than the outer gap g2 located at . For example, the inner gap g1 of the horizontal passage H may be formed to be 0.2 mm, and the outer gap g2 may be formed to be 0.15 mm. Specifically, the first line groove 114 inside the upper circumferential surface 111 may be formed to be more depressed than the second line groove 115 outside the upper circumferential surface 111 .

Preferably, the horizontal passage H may be formed so that the gap gradually decreases toward the outside of the mold 100 .

In this way, if the inner gap g1 of the horizontal passage H is formed to be larger than the outer gap g2, even if the molten aluminum flows along the horizontal passage H, it is discharged to the outside of the mold 100 by surface tension. This is prevented, and only the gas can be discharged along the horizontal flow path (H).

7 shows a casting (C) cast by the pressure casting apparatus 1 according to an embodiment of the present invention.

When comparing FIG. 7 with FIG. 1 , in the pressure casting apparatus 1 according to an embodiment of the present invention, the gas by the core 200 inside the mold 100 flows through the first vertical flow path V1, the second 2 Since it is simultaneously discharged to the outside of the mold 100 through the vertical passage (V2), the sintering vent, the slit vent, and the horizontal passage (H), the appearance quality of the casting (C) by pressure casting can be improved.

Meanwhile, the core 200 according to an embodiment of the present invention is characterized in that a coating layer is formed on its outer circumferential surface. Hereinafter, the effect of the coating layer will be described in detail by specific examples.

<Example>

As the foundry sand for the core 200, Vietnamese sand composed of chemical components of SiO2 99.17%, Al2O3 0.0001%, Fe2O3 0.127%, CaO 0.037%, MgO 0.098%, TiO2 0.279%, and K2O 0.001% was used. An alcoholic coating agent was applied to the outer circumferential surface of the core 200 manufactured by the method to form a coating layer. Thereafter, the core 200 was inserted into the mold 100 to cast a hollow aluminum casting product by a pressure casting method.

<Comparative example>

The core 200 was manufactured in the same manner as in the above embodiment, and unlike the embodiment, a separate coating layer was not formed. Thereafter, the core 200 was inserted into the mold 100 to cast a hollow aluminum casting product by a pressure casting method.

8 shows the inner surface of an aluminum cast product according to an embodiment of the present invention and a comparative example, and FIG. 9 is a SEM image of the surface microstructure of a core 200 according to an embodiment of the present invention and a comparative example. .

As shown in FIGS. 8 and 9 , in the case of the embodiment, erosion by the molding sand of the core 200 did not occur, so the inner surface of the cast product appeared smooth, and in the SEM image of the core 200, the core 200 It was confirmed that erosion hardly occurred on the surface.

On the other hand, in the case of Comparative Example, the inner surface of the cast product appeared rough due to erosion by the molding sand, and it was confirmed that erosion occurred on the surface of the core 200 in the SEM image of the core 200.

That is, when a coating agent is applied to the outer circumferential surface of the core 200 to form a coating layer, the coating agent fills the gaps between the molding sands, thereby suppressing the effect of physical seizure, and thereby improving the erosion of the casting (C) during pressure casting. can

The above description of the present invention is for illustrative purposes, and those skilled in the art can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included in the scope of the present invention.

1 pressure casting device
100 molds
200 medium
300 ejection unit
V1 1st vertical passage
V2 2nd vertical passage
H horizontal flow
C casting

Claims (8)

a mold configured to include an upper mold, a lower mold having a pinhole, and a cavity formed by combining the upper mold and the lower mold;
a core disposed inside the cavity; and
A hollow pin guide inserted into the pin hole, a hollow sleeve bent inserted into the pin guide and formed to form a predetermined gap with the inner circumferential surface of the pin guide, and an eject pin inserted into the sleeve vent. ejection unit; Including, pressure casting apparatus. According to claim 1,
The pressure casting apparatus, characterized in that the coating layer is formed on the outside of the sand core. According to claim 1,
A plurality of vent holes pass through the upper mold,
The pressure casting apparatus, characterized in that at least one of a sintering vent and a slit vent for discharging gas is disposed in the vent hole. According to claim 1,
A plurality of cut surfaces extending in the axial direction of the sleeve vent are formed around the outer circumferential surface of the sleeve vent,
The pressure casting apparatus, characterized in that a first vertical flow path is formed between the cut surface and the inner circumferential surface of the pin guide. According to claim 4,
The cut surface is characterized in that arranged to form an equal interval with the adjacent cut surface, the pressure casting apparatus. According to claim 1,
A pressure casting apparatus, characterized in that a second vertical flow path is formed between the eject pin and the inner circumferential surface of the sleeve vent. According to claim 1,
The pressure casting apparatus, characterized in that the mold is formed with a plurality of horizontal flow passages extending horizontally from the cavity to the outside of the mold. According to claim 7,
The pressure casting apparatus, characterized in that the inner gap on the cavity side of the horizontal passage is larger than the outer gap on the outside of the mold.

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