JP2003225750A - Die casting apparatus and casting method in die casting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an effective technique for surely preventing entrapment of gas into a cast product at the injection time in a die casting apparatus. <P>SOLUTION: In a sleeve 160 in the die casting apparatus 100, a first exhausting hole 162 and a second exhausting hole 163, a molten metal supplying hole 164 and an oxygen supplying hole 165 which are passed through between the outer surface of the sleeve and a sleeve hollow part 166, are arranged. In a sleeve bush 150, a communicating groove 151 communicating the first exhausting hole 162 and the second exhausting hole 163, is formed. An exhausting path 170 is formed with the first exhausting hole 162, the second exhausting hole 163 and the communicating groove 151. When the injecting operation is performed, the molten metal W pressed with a plunger 161, is injected toward a cavity 130. At this time, such air in a pressing zone as to push into the cavity 130 together with the molten metal W, is exhausted into the upstream side (out of the pressing zone) in the plunger 161 through the exhausting path 170. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for casting a cast product in a die casting apparatus, and more particularly to a technique for injecting molten metal into a cavity formed by a die.

[0002]

2. Description of the Related Art Generally, a die casting apparatus injects a molten metal into a cavity (hollow portion) formed by a mold at high speed and high pressure to cast a cast product. This type of die casting device has a structure in which the molten metal supplied in the sleeve is pressurized by a plunger and injected into the cavity. In this die casting device, when the molten metal is pressurized and injected together with the gas remaining in the sleeve, there is a problem that the gas is entrained in the cast product and a pinhole is generated. Therefore, conventionally, for example, Japanese Patent Application Laid-Open No. 7-124727 discloses a technique of positively letting out the air, which is going to enter the cavity together with the molten metal, by the pressurizing operation of the plunger, to the outside of the sleeve. In the die casting device described in this publication, an air vent groove extending along the moving direction of the plunger is formed on the inner surface of the sleeve. The air pressurized by the pressing operation of the plunger is allowed to escape to the outside of the sleeve through the air vent groove.
According to the above conventional die casting apparatus, the air inside the sleeve is allowed to escape to the outside of the sleeve, so that it is possible to prevent air from being entrained in the cast product and to make it difficult to form pinholes or the like in the cast product.

[0003]

However, in the above-mentioned conventional die casting apparatus, since the entire air vent groove faces the molten metal in the sleeve, the molten metal in which the liquid level fluctuates in the sleeve during the pressing operation by the plunger. May block the air vent groove. Therefore, in the above-mentioned conventional die casting apparatus, the air in the sleeve may not be able to escape to the outside of the sleeve, and there is a problem that the original purpose of preventing the air from being entrained in the cast product can be fulfilled.
Therefore, the present invention has been made in view of the above points, and the problem is that the die casting apparatus,
It is an object of the present invention to provide an effective technique for reliably preventing gas from being caught in a cast product during injection.

[0004]

In order to solve the above problems, the die casting apparatus of the present invention is constructed as described in claims 1-5. The casting method in the die casting apparatus of the present invention is as described in claims 6 and 7. In the die casting apparatus, the gas pressurized together with the molten metal through the plunger is allowed to escape through an escape path having an independent portion that does not face the inside of the sleeve in the die casting apparatus. It is a technology that can reliably prevent the entrainment of gas in a cast product.

In the die casting machine according to claim 1,
A mold, sleeve, plunger, etc. are provided. For example, a pair of molds are clamped together to form a cavity (hollow portion) in the shape of a cast product. The sleeve is adapted to communicate with this cavity. A plunger is accommodated in the sleeve, and the plunger can reciprocate in the sleeve. Therefore, by supplying the molten metal into the sleeve and moving the plunger in a direction of pressurizing the molten metal, the molten metal is pressurized by the plunger and injected toward the cavity. As a result, a cast product having a shape corresponding to the cavity is cast. Further, this die casting device is provided with an escape path. The escape path is configured to have an independent portion that does not face the inside of the sleeve. When the molten metal is pressurized by the plunger, the gas in the pressurized region, which is pressurized together with the molten metal in the sleeve, escapes to the outside of the pressurized region through this escape path.
This escape path may be formed in the sleeve or in the plunger or the like. Further, this escape path can be configured by holes, grooves, or a combination of holes and grooves. Further, this escape path may be opened / closed in accordance with the relative movement of the sleeve and the plunger, or may be opened / closed via an opening / closing valve or the like. This can prevent the gas pressurized by the plunger, for example air, from being pushed into the cavity.
In particular, since the escape route has a portion that does not face the inside of the sleeve, the escape route is less likely to be clogged with the molten metal as compared with the conventional technique in which the escape groove is formed on the inner surface of the sleeve along the moving direction of the plunger. Therefore,
It is possible to maintain the escape of gas to the outside of the pressurizing region during injection, and to reliably prevent gas from being caught in the cast product. As described above, according to the die casting apparatus according to the first aspect, it is possible to prevent the gas from being pushed into the cavity by using the escape passage, and the escape passage is difficult to be clogged. It is possible to reliably prevent gas from being caught in the product.

Here, the escape route according to claim 1 is
It is preferably formed on at least the sleeve as claimed in claim 2. This escape path may be formed only in the sleeve, or may be formed over the sleeve and another member adjacent to the sleeve. This allows
An escape route with a simple structure can be realized.

Further, in the die casting apparatus according to the third aspect, the escape route is constituted by the inlet hole and the outlet hole and the independent route. The inlet hole and the outlet hole face the inside of the sleeve, and are formed in the sleeve, for example. The independent path is a path that connects the inlet hole and the outlet hole, and may be formed, for example, in a sleeve bush adjacent to the sleeve, or may be formed in a position in the sleeve that does not face the sleeve. Before supplying the molten metal into the sleeve, the inlet hole and the outlet hole are located in the pressurizing region. That is, the escape path is a closed path that communicates with the pressure area in the sleeve. At this time, the gas in the pressurized area is not pressurized by the plunger,
It is not necessary to let the gas in the pressurized area escape through the escape path. Then, in the process of pressurizing the molten metal with the plunger, the inlet hole is located in the pressurizing area and the outlet hole is located outside the pressurizing area. That is, the pressurizing region is communicated with the outside of the pressurizing region only when the plunger performs the pressurizing operation. This is rational because the escape route can be opened and closed as needed.

Further, in the die casting apparatus according to the fourth aspect, the inlet hole and the outlet hole are formed in the sleeve. Further, the independent path is formed by forming a communication groove that communicates the inlet hole and the outlet hole in another member adjacent to the sleeve, for example, a sleeve bush. With this, the relief path can be formed only by forming the hole in the sleeve and forming the groove in the sleeve bush, and thus the relief path can be easily processed.

The sleeve according to any one of claims 1 to 4 is preferably provided with an active gas supply port for supplying an active gas into the sleeve as described in claim 5.
The "active gas" here is an active gas such as oxygen and carbon dioxide, and oxygen is preferably used. Oxygen gas supplied from the active gas supply port can create an oxygen atmosphere in the cavity. As a result, the molten metal having a high temperature at the time of injection can react with oxygen to form an oxide, and gas entrapment in the cast product can be prevented.
As described above, when the gas in the region pressurized by the plunger escapes through the escape path at the time of injection, and the inside of the cavity is preliminarily set to the oxygen atmosphere, the gas can be more reliably prevented from being caught in the cast product.

According to the casting method in the die casting apparatus according to the sixth aspect, in the injection operation, it is possible to prevent the gas pressurized by the plunger, for example, air, from being pushed into the cavity from the pressure area of the sleeve. You can In particular, since the escape path has a portion that does not face the inside of the sleeve, the escape path is less likely to be clogged with the molten metal as compared with the prior art in which an escape groove is formed on the inner surface of the sleeve along the moving direction of the plunger. Therefore, at the time of injection, the escape of gas to the outside of the pressurizing region can be maintained, and the gas can be prevented from being caught in the cast product. As described above, according to the casting method in the die casting apparatus according to the sixth aspect, it is possible to prevent the gas from being pushed into the cavity by using the escape passage, and at the same time, to prevent the escape passage from being clogged. Therefore, it is possible to reliably prevent the gas from being caught in the cast product.

Further, in the casting method in the die casting apparatus according to the seventh aspect, it is preferable that the active gas supply operation is performed before the injection operation. In this active gas supply operation, for example, oxygen can be supplied into the sleeve to make the cavity an oxygen atmosphere. As a result, the molten metal having a high temperature at the time of injection can react with oxygen to form an oxide, and gas entrapment in the cast product can be prevented. As described above, when the gas in the region pressurized by the plunger escapes through the escape path at the time of injection, and the inside of the cavity is preliminarily set to the oxygen atmosphere, the gas can be more reliably prevented from being caught in the cast product.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to a technique of supplying molten metal to a cavity formed by a mold in a tilt type die casting device. Here, FIG. 1 is a partial cross-sectional view of the die casting apparatus 100 of the present embodiment, showing a state during an oxygen supply operation.

As shown in FIG. 1, a die casting apparatus 100 is provided.
Is inclined at a predetermined angle with respect to the horizontal plane. The inclined die casting apparatus 100 is fixed to the die plate 140 via a fixed die 110, a movable die 120, fixed die 110 and die plates 140 and 142 for clamping the movable die 120, and a sleeve bush 150. Plunger 160 which reciprocates through sleeve 160 and sleeve hole 166 of sleeve 160 in the direction of arrow 10 or 20 in the figure.
It is equipped with 61 etc.

When the fixed mold 110 and the movable mold 120 are clamped to each other, a cavity (hollow portion) 130 corresponding to the shape of the cast product is formed at a position where the two molds face each other. Further, the cavity 130 communicates with the sleeve hole 166 via the gate 131. The sleeve 160 has
A first relief hole 162 and a second relief hole 163 are formed to penetrate between the outer surface and the sleeve hole 166. Further, the sleeve 160 is provided with a hot water supply port 164 for supplying molten metal to the sleeve hole 166 and an oxygen supply port 165 for supplying oxygen to the sleeve hole 166. The oxygen supplied from the oxygen supply port 165 corresponds to the active gas in the present invention. A communication groove 151 is formed in the sleeve bush 150 adjacent to the sleeve 160 to connect the first relief hole 162 and the second relief hole 163. Therefore, one relief path 170 is formed by the first relief hole 162, the second relief hole 163, and the communication groove 151.
Are formed. This first relief hole 16
2 corresponds to the inlet hole in the present invention, and the second relief hole 163 corresponds to the outlet hole in the present invention. Further, the communication groove 151 corresponds to the independent path in the present invention.

Next, a method of supplying molten metal to the cavity 130 in the die casting apparatus 100 having the above-mentioned structure will be described with reference to FIGS. Here, FIG. 2 is a partial cross-sectional view of the die casting apparatus 100, showing a state during a hot water supply operation. Further, FIG. 3 is a partial cross-sectional view of the die casting apparatus 100, showing a state during an injection operation.

In performing the injection operation for injecting the molten metal into the cavity 130, an oxygen supply operation for supplying oxygen to the sleeve hole 166 and a hot water supply operation for supplying the molten metal to the sleeve hole 166 are performed. In addition, the oxygen supply operation is performed by the sleeve hole 16
It is performed before the hot water supply operation of supplying the molten metal to No. 6. First, at the time of oxygen supply operation, as shown in FIG. 1, oxygen is blown into the sleeve hole 166 from the oxygen supply port 165 with the plunger 161 set at the position where the hot water supply port 164 is closed. As a result, the region from the cavity 130 to the sleeve hole 166 is in an oxygen atmosphere. At this time, since the escape path 170 formed by the first escape hole 162, the second escape hole 163, and the communication groove 151 is a closed region that communicates with the sleeve hole 166, oxygen escapes to the outside of the device through the escape path 170. There is no leakage. During the oxygen supply operation, the escape passage 170 is configured so as not to communicate with the outside of the sleeve hole 166.
The oxygen filled in 66 is difficult to escape. Further, since oxygen is supplied in the closed region, the efficiency of oxygen replacement in the cavity 130 is good.

When the above oxygen supply operation is completed, a hot water supply operation is next performed. In this hot water supply operation, the plunger 161 is retracted in the direction of the arrow 20 in FIG. 1, and hot metal is supplied from the hot water supply port 164. At this time, the supply of oxygen from the oxygen supply port 165 is maintained. As a result, it is possible to prevent outside air from entering the sleeve hole 166 during the hot water supply operation as much as possible. As shown in FIG. 2, when the supply of the molten metal W is completed, the gate 131 is shielded by the molten metal W, and the cavity 130 and the sleeve hole 166 are blocked by the molten metal W. That is, when a predetermined amount of molten metal W is supplied, the cavity 130 and the sleeve hole 16
It is preferable to set the inclination angle of the die casting apparatus 100 such that the die 6 and the die 6 are blocked by the molten metal W.
Thereby, the cavity 130 can be maintained in the oxygen atmosphere. Then, by making the cavity 130 into an oxygen atmosphere, the high temperature molten metal at the time of injection reacts with oxygen to form an oxide. For example, in the case of aluminum die casting, aluminum oxide is formed. As a result, it is possible to prevent gas from being entrained inside the cast product and reduce defects such as pinholes. The sleeve hole 166
As the gas to be blown into, an active gas other than oxygen, such as carbon dioxide gas, may be used.

When the hot water supply operation is completed, the injection operation is performed next. In this injection operation, the plunger 161 is moved to the position shown in FIG.
It moves forward in the direction of the arrow 10 and the molten metal is pressurized by the plunger 161. This allows the plunger 1
The molten metal W pressurized by 61 is injected toward the cavity 130. At this time, although the sleeve hole 166 is replaced with oxygen to some extent, some air (gas) is mixed in during the hot water supply operation. Therefore, it is necessary to discharge the air (gas) from the sleeve hole 166 in order to prevent the gas in the sleeve hole 166 from being caught in the cast product.

In the present embodiment, as shown in FIG. 3, in the pressurizing process by the plunger 161, the relief path 170 is communicated with the upstream side of the plunger 161 (outside the pressurizing region). That is, the first relief hole 162 is located in the pressure area, and the second relief hole 163 is located outside the pressure area. This allows the plunger 16
The pressurizing operation of No. 1 causes the cavity 130 together with the molten metal W.
The air (gas) in the pressurizing region that is about to be pushed into is released to the upstream side (outside the pressurizing region) of the plunger 161 through the escape path 170. That is, the plunger 16
The air (gas) in the pressurizing region pressurized by 1 moves to the outside of the pressurizing region through the escape path 170 due to the pressure balance. As a result, the air (gas) in the pressurizing region is allowed to escape, so that the air can be prevented from being trapped in the cast product. Further, in the present embodiment,
In the pressurizing process by the plunger 161, the escape route 1
Only the first relief hole 162 that constitutes 70 faces the pressure area. That is, the escape path 170 is configured to have an independent portion that does not face the pressurizing region, the communication groove 151, and the second escape hole 163. As a result, compared with the case where the entire escape passage 170 faces the pressurizing region, the passage is less likely to be clogged with the molten metal W even if the injection is constantly repeated.

As described above, according to the present embodiment, the inside of the cavity 130 is preliminarily set to the oxygen atmosphere, and the air (gas) in the pressurized region pressurized through the plunger 161 during the injection operation is released. Since the passage 170 is released to the outside of the pressurizing region, it is possible to reliably prevent the air from being caught in the casting. In particular, the escape route 170 is
Since the escape route 170 has a few portions that do not face the inside of the sleeve 160 and the escape route 170 faces the pressurizing region during the injection operation, the escape route 170 is less likely to be clogged with the molten metal W. Further, according to the present embodiment, it is possible to realize the escape path 170 having a simple structure using the escape holes 162 and 163 of the sleeve 160 and the communication groove 151 of the sleeve bush 150. Further, according to the present embodiment, since the pressurizing area is communicated with the outside of the pressurizing area only when the plunger 161 performs the pressurizing operation, the relief path 170 can be opened and closed as needed. Target.

The present invention is not limited to the above embodiment, and various applications and modifications can be considered.
For example, each of the following modes to which the above-described embodiment is applied can be implemented.

(A) In the above embodiment, the sleeve 16
Although the die-casting device having a configuration in which 0 or the like is inclined, the present invention can be applied to a die-casting device other than the inclination type.

(B) In the above embodiment, the escape path 1 is provided in the sleeve bush 150 and the sleeve 160.
Although the case of forming 70 is described, the location where the escape path is provided is the sleeve bush 150 or the sleeve 160.
Not limited to. For example, the escape path can be formed in the plunger 161.

[0024]

As described in detail above, according to the present invention,
With the die casting device, it is possible to realize a technique that is effective in reliably preventing gas entrainment in a cast product during injection.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a die casting apparatus 100 of the present embodiment, showing a state during an oxygen supply operation.

FIG. 2 is a partial cross-sectional view of the die casting apparatus 100,
The state at the time of hot water supply operation is shown.

FIG. 3 is a partial cross-sectional view of the die casting apparatus 100,
The state at the time of injection operation is shown.

[Explanation of symbols]

100 ... Die casting machine 110 ... Fixed mold 120 ... Movable mold 130 ... Cavity (hollow part) 150 ... Sleeve bush 151 ... Communication groove 160 ... Sleeve 161 ... Plunger 162 ... First relief hole 163 ... Second relief hole 164 ... Hot water supply port 165 ... Oxygen supply port 166 ... Sleeve hole W ... molten metal

Continued front page    (72) Inventor Masakazu Hirano             2-1, Toyota-cho, Kariya City, Aichi Stock Association             Inside Toyota Toyota Industries (72) Inventor Noriaki Ito             521 Nagashima, Hamakita City, Shizuoka Prefecture             In tex

Claims (7)

[Claims] 1. A mold which forms a cavity, a sleeve which communicates with the cavity of the mold, and a plunger which reciprocates in the sleeve, wherein the molten metal supplied into the sleeve is the plunger. By applying pressure through
A die-casting device for injecting the molten metal toward the cavity, comprising: an escape path for escaping a gas in a pressurization region pressurized in the sleeve via the plunger to the outside of the pressurization region. A die-casting device configured to have an independent portion that does not face the inside of the sleeve. 2. The die casting apparatus according to claim 1, wherein the escape path is formed at least in the sleeve. 3. The die casting apparatus according to claim 1, wherein the escape path has an inlet hole and an outlet hole facing the inside of the sleeve, and an independent path communicating the inlet hole and the outlet hole. Before the molten metal is supplied into the sleeve, the inlet hole and the outlet hole are located in the pressurizing area, and in the process of pressing by the plunger, the inlet hole is located in the pressurizing area, and the outlet is The die-casting device, wherein the hole is configured to be located outside the pressing area. 4. The die casting apparatus according to claim 3, wherein the inlet hole and the outlet hole are formed in the sleeve, and the independent path is formed in a separate member adjacent to the sleeve. Die casting machine characterized by 5. The die casting apparatus according to claim 1, wherein the sleeve is provided with an active gas supply port for supplying an active gas into the sleeve. Die casting equipment. 6. A die casting apparatus comprising a die forming a cavity, a sleeve communicating with the cavity of the die, and a plunger reciprocating in the sleeve, wherein the molten metal supplied into the sleeve is melted. A casting method comprising an injection operation of injecting the molten metal toward the cavity by pressurizing it through a plunger, wherein the injection operation involves pressurization in the sleeve through the plunger. A casting method in a die casting apparatus, characterized in that the gas in the pressure region is allowed to escape to the outside of the pressure region through an escape path having an independent portion that does not face the inside of the sleeve. 7. The casting method in the die casting apparatus according to claim 6, wherein an active gas supply operation is performed to supply an active gas into the sleeve to make the cavity an active gas atmosphere before the injection operation. A casting method in a die-casting apparatus, which comprises: