JP5136211B2 - Vacuum die casting apparatus and vacuum die casting method - Google Patents

Description

  The present invention relates to a vacuum die casting apparatus and a vacuum die casting method, and more specifically to a technique for performing casting by reducing the pressure inside a cavity of a mold.

  In a vacuum die casting apparatus that decompresses the inside of a cavity using a decompression device such as a decompression valve, conventionally, a technique for controlling the opening of the decompression valve based on detection information by a molten metal detection sensor is known. There are also documents to be disclosed (see, for example, Patent Document 1).

In the vacuum die casting apparatus represented by the prior art, the pressure reducing valve is directly attached to a mold forming a cavity (see FIG. 7).
However, in the vacuum die casting apparatus having the configuration shown in FIG. 7, it is necessary to provide a molten metal detection sensor around the pressure reducing valve, so that the pressure reducing valve structure is greatly complicated. Accordingly, it is necessary to position the pressure reducing valve so that the molten metal does not flow in the vicinity of the exhaust valve. Therefore, it has been difficult to ensure the flatness of the pressure reducing valve portion in mold matching.
Further, since it is necessary to dispose a cooling structure in the vicinity of the molten metal detection sensor, a mold distortion is generated in the entire mold due to a temperature difference generated between the molten metal and the cavity portion into which the high temperature molten metal flows. As a result of the occurrence of a gap in the portion, a phenomenon that the molten metal jumps out (hereinafter referred to as hot water spray) may occur.
JP 2007-268550 A

  The present invention relates to a vacuum die casting apparatus and a vacuum die casting method, which ensures the flatness of a pressure reducing valve portion in mold matching, and injects even if mold distortion occurs and the width of the matching portion of the pressure reducing valve portion changes. The present invention proposes a technique capable of preventing molten metal from being blown without being affected by molding.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, a fixed mold and a movable mold that is close to and away from the fixed mold, and a mold in which a cavity is formed between the fixed mold and the movable mold, A pressure reducing valve for reducing the pressure inside the cavity, a pressure reducing device for controlling pressure reduction by the pressure reducing valve, a molten metal detection sensor disposed on the pressure reducing valve and connected to the pressure reducing device; And after reducing the pressure in the cavity with the pressure reducing valve and the pressure reducing device, the molten metal is injection molded into the cavity, and the opening of the pressure reducing valve is adjusted based on the detection of the molten metal by the molten metal detection sensor. The vacuum die casting apparatus is controlled by the decompression apparatus, and the decompression valve is attached with a spacer interposed between the mold and the mold.

  According to a second aspect of the present invention, the pressure reducing valve includes a fixed mold side pressure reducing valve disposed in the fixed mold and a movable mold side pressure reducing valve disposed in the movable mold, and the vacuum die casting apparatus When injection molding is performed, a gap through which the molten metal can flow is formed at a joint portion between the fixed mold side pressure reducing valve and the movable mold side pressure reducing valve.

  According to a third aspect of the present invention, the movable mold is provided with an injection molded product extrusion device, and the movable mold side pressure reducing valve portion of the movable mold is driven separately from the injection molded product extrusion device. A device is provided.

According to a fourth aspect of the present invention, a cavity is formed by a mold including a fixed mold and a movable mold that contacts the fixed mold, and a spacer is interposed between the mold and the mold is provided. After the pressure is reduced by the pressure reducing valve and the pressure reducing device, the molten metal is injection-molded into the cavity, and at the same time, based on detection of the molten metal by the molten metal detection sensor connected to the pressure reducing device and disposed in the pressure reducing valve. An injection step for controlling the opening of the pressure reducing valve by the pressure reducing device, and a mold opening step for allowing the injection mold to be taken out from the fixed mold by separating the movable mold from the fixed mold. In the gap between the movable mold side pressure reducing valve and the fixed mold side pressure reducing valve disposed in the fixed mold by a casting burr extrusion device provided in the movable mold side pressure reducing valve portion of the movable mold. Extruding the casting burr pear, and casting burr extrusion step, provided in the movable mold, the injection-molded article extrusion apparatus is an apparatus comprising extruding an injection molded article, a molded article extrusion step.

  According to a fifth aspect of the present invention, the casting burr extrusion process is completed before the molded product extrusion process starts.

  According to the present invention, the flatness of the pressure reducing valve portion in mold matching is ensured, and even if the mold distortion occurs and the width of the matching portion of the pressure reducing valve portion changes, it is not affected by injection molding, Hot water blowing can be prevented.

Next, embodiments of the invention will be described.
FIG. 1 is a sectional view showing a vacuum die casting apparatus according to the present invention before injection molding.
FIG. 2 is a cross-sectional view during injection molding showing the vacuum die casting apparatus.
FIG. 3 is an enlarged cross-sectional view showing the pressure reducing valve portion of the vacuum die casting apparatus before the injection process.
FIG. 4 is an enlarged cross-sectional view of the pressure reducing valve portion during the injection process.
FIG. 5 is an enlarged cross-sectional view of the pressure reducing valve portion during the mold opening process.
FIG. 6 is an enlarged cross-sectional view showing the decompression valve portion during the casting burr extrusion process.
FIG. 7 is a sectional view showing a vacuum die casting apparatus according to the prior art.
It should be noted that the technical scope of the present invention is not limited to the following examples, but broadly covers the entire scope of the technical idea that the present invention truly intends, as will be apparent from the matters described in the present specification and drawings. It extends.

  The vacuum die casting apparatus and the vacuum die casting method according to the present invention will be described below. In this specification, for the sake of convenience, the right side in FIG. 1 will be described as the right side and the left side as the left side.

[Overall configuration of vacuum die casting apparatus 10]
First, the overall configuration of the vacuum die casting apparatus 10 will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, the vacuum die casting apparatus 10 includes a fixed mold 11 and a movable mold 12 configured to be close to and away from the fixed mold 11. A cavity 10a is formed between the fixed mold 11 and the movable mold 12 when the movable mold 12 approaches the fixed mold 11 in the direction of arrow A in FIG. Is done.

  As shown in FIGS. 1 and 2, the vacuum die casting apparatus 10 is provided with a substantially cylindrical sleeve 17 protruding rightward. The short cylindrical plunger 18 is slid leftward in the sleeve 17, and the molten metal supplied into the sleeve 17 is extruded from the hot water supply port 17a and injected into the cavity 10a.

The vacuum die casting apparatus 10 is further provided with an injection molded product extruding apparatus 13 on the movable mold 12. The injection molded product extruding device 13 is a hydraulic cylinder, and the injection molded product extruding device 13 is connected to an extruding plate 14 slidable left and right within the movable mold 12. A plurality of extrusion pins 15, 15, 15... Penetrating from the movable mold 12 to the cavity 10 a are connected.
Then, by driving a hydraulic cylinder of the injection molded product extrusion device 13, the extrusion pins 15, 15, 15... Are protruded into the cavity 10a through the extrusion plate 14, and injection molded into the cavity 10a. The molded product is extruded from the movable mold 12.

  The fixed mold 11 and the movable mold 12 are provided with a fixed mold side decompression valve 21 and a movable mold side decompression valve 22 (hereinafter, decompression valves 21 and 22) for decompressing the inside of the cavity 10a. Further, the vacuum die casting apparatus 10 is connected to the decompression valves 21 and 22 through an electric circuit and an air passage, and is controlled by the decompression apparatus 40 that controls decompression by the decompression valves 21 and 22 and the fixed mold side decompression valve 21. And a molten metal detection sensor 43 which is provided and electrically connected to the pressure reducing device 40. The decompression device 40 includes a storage device, an arithmetic unit, a controller, a vacuum pump, and the like. As will be described later, the exhaust valve 24 disposed in the decompression valves 21 and 22 and the casting burr extrusion device 29 are driven by the controller. Control etc.

  When injection molding is performed by the vacuum die casting apparatus 10, the inside of the cavity 10a is decompressed by the decompression valves 21 and 22 and the decompression apparatus 40, and then the molten metal is injected into the cavity 10a, and the molten metal detection sensor. Based on the detection of the molten metal by 43, the pressure reducing device 40 controls the pressure reducing valves 21 and 22 to be closed by a solenoid actuator. The pressure reducing valves 21 and 22 can be closed by hydraulic pressure or air pressure.

  Here, the fixed mold side pressure reducing valve 21 is attached with a fixed mold side spacer 27 interposed between the fixed mold 11 and the fixed mold 11. The fixed mold side spacer 27 is a member made of steel for molds formed in a substantially lid shape so that the right end portion of the fixed mold side pressure reducing valve 21 can be fitted. The fixed mold 11 is formed with a recess so that the fixed mold side spacer 27 can be fitted. That is, the fixed mold side spacer 27 is connected to the concave portion of the fixed mold 11 with a fastening member such as a bolt, and the fixed mold side pressure reducing valve 21 is connected to the fixed mold side spacer 27 with a fastening member such as a bolt.

  With the above-described configuration, even when mold distortion occurs in the fixed mold 11 due to a temperature difference generated in the entire mold during injection molding, the fixed mold side spacer 27 can absorb the distortion. Therefore, the fixed mold side pressure reducing valve 21 portion can be prevented from being affected, and the flatness of the fixed mold side pressure reducing valve 21 can be ensured.

  Further, the movable mold side pressure reducing valve 22 is also mounted with a movable mold side spacer 28 interposed between the movable mold 12 and the fixed mold side pressure reducing valve 21. That is, even when a mold distortion occurs in the movable mold 12, the movable mold side spacer 28 can absorb the distortion, so that the movable mold side pressure reducing valve 22 portion is not affected.

[Vacuum die casting method]
Next, a vacuum die casting method using the vacuum die casting apparatus 10 will be described with reference to FIGS. FIG. 3 is an enlarged cross-sectional view showing the pressure reducing valves 21 and 22 of the vacuum die casting apparatus 10 before the injection process. As shown in FIG. 3, the stationary mold 11 of the vacuum die casting apparatus 10 is provided with a stationary mold side pressure reducing valve 21 via the stationary mold side spacer 27.

  An exhaust valve 24 whose driving is controlled by the pressure reducing device 40 is slidably disposed in the fixed mold side pressure reducing valve 21. Further, an exhaust passage 23 is formed to communicate the cavity 10a and the decompression device 40, and the cavity 10a is exhausted by driving a vacuum pump provided in the decompression device 40. Specifically, when injection molding is performed by the vacuum die casting apparatus 10, the exhaust valve 24 is opened under the control of the decompression apparatus 40, and the air in the cavity 10a is exhausted in the direction of arrow B in FIG. Later, the molten metal is injected into the cavity 10a.

  Further, at the time of injection molding, the exhaust valve 24 is closed to block the exhaust to the exhaust passage 23. That is, when the molten metal detection sensor 43 detects the molten metal injected into the cavity 10a, the solenoid actuator is driven by the control of the pressure reducing device 40, and the exhaust valve 24 is slid to the right and closed, whereby the exhaust passage 23 is closed. The exhaust gas is shut off and the molten metal is configured not to flow into the exhaust passage 23.

  On the other hand, the movable die 12 of the vacuum die casting apparatus 10 is provided with a movable pressure reducing valve 22 via the movable spacer 28. The movable mold side pressure reducing valve 22 of the movable mold 12 is provided with a casting burr extrusion device 29 that is driven separately from the injection molded product extrusion device 13. The casting burr extrusion device 29 is a hydraulic cylinder connected to the decompression device 40, and the casting burr extrusion device 29 has an extrusion plate 30 configured to be slidable left and right within the movable type decompression valve 22. Connected to the extrusion plate 30 are a plurality of extrusion pins 31, 31, 31... Penetrating from the movable mold side pressure reducing valve 22 toward the fixed mold side pressure reducing valve 21.

Then, by driving the hydraulic cylinder of the casting burr extrusion device 29 to the right side under the control of the decompression device 40, the extrusion pins 31, 31, 31... The casting burr remaining between the pressure reducing valve 21 is pushed out.
In the present embodiment, the casting burr extrusion device 29 uses a hydraulic cylinder, but it is also possible to use an extrusion mechanism having a different configuration such as a disc spring method or an air extrusion method. Further, the extrusion timing can be performed at an arbitrary timing by receiving a mold opening signal from the vacuum die casting apparatus 10 and setting a timer.

  Further, when the movable mold 12 is close to the fixed mold 11 and injection molding is performed by the vacuum die casting apparatus 10, that is, in the state shown in FIG. 3, the fixed mold side pressure reducing valve 21 and the movable mold side A gap through which the molten metal can flow is formed at a joint portion between the pressure reducing valve 22 and the pressure reducing valve 22. Specifically, the fixed mold side pressure reducing valve 21 and the movable mold side are arranged so that the joint between the fixed mold side pressure reducing valve 21 and the movable mold side pressure reducing valve 22 forms a gap having a width d shown in FIG. Each of the pressure reducing valves 22 is disposed on the fixed mold 11 and the movable mold 12.

FIG. 4 is an enlarged cross-sectional view of the pressure reducing valves 21 and 22 during the injection process.
In the injection process, as described above, after the pressure inside the cavity 10a is reduced by the pressure reducing valves 21 and 22 and the pressure reducing device 40, the molten metal is injection molded in the direction of the arrow C in FIG. . Then, based on the detection of the molten metal by the molten metal detection sensor 43, the exhaust valve 24 is closed in the direction of arrow D in FIG. 4 by the control of the pressure reducing device 40, and the exhaust from the cavity 10a to the exhaust passage 23 is shut off. The flow of molten metal into the exhaust passage 23 is blocked.

FIG. 5 is an enlarged cross-sectional view showing the pressure reducing valves 21 and 22 during the mold opening process.
In the mold opening process, the movable mold 12 is separated from the fixed mold 11 in the direction of arrow E in FIG. 5, whereby an injection molded product can be taken out from the fixed mold 11.

FIG. 6 is an enlarged cross-sectional view showing the pressure reducing valves 21 and 22 during the casting burr extrusion process.
In the casting burr extrusion process, the extrusion cylinders 31, 31, 31... Are projected through the extrusion plate 30 by driving the hydraulic cylinder of the casting burr extrusion device 29 in the direction of arrow F in FIG. The casting burr left between the movable mold side pressure reducing valve 22 and the fixed mold side pressure reducing valve 21 is pushed out in the direction of arrow G in FIG.
Thereafter, in the molded product extrusion step, the injection molded product is extruded by the injection molded product extrusion device 13 provided in the movable mold 12 as described above.

With the configuration described above, when injection molding is performed, the molten burr is allowed to flow from the gap into the mating portion, and then the cast burr generated by the flowed molten metal can be extruded by the cast burr extrusion device 29. it can. That is, by adopting a configuration in which the molten metal can flow into the mating portions of the pressure reducing valves 21 and 22, even if the width of the mating portions of the pressure reducing valves 21 and 22 changes due to mold distortion, Since the burr) can be removed every shot, the injection molding is not affected.
Further, since the possibility of hot water spraying due to the sandwiching of the casting burr can be eliminated in this way, it is not necessary to strictly adjust the width of the mating portion when the pressure reducing valves 21 and 22 are disposed. It is easy to ensure the flatness of the pressure reducing valves 21 and 22 in the alignment.
In addition, the width d of the gap in the present embodiment is 0.1 to 1. .5 in the initial cold state from the viewpoint of easy inflow of the molten metal and securing the flatness of the pressure reducing valves 21 and 22 in mold matching. It is desirable to make it about 0 mm.

Here, the casting burr extrusion process is completed by the time the molded product extrusion process starts. Thereby, malfunctions, such as a galling in the runner part of an injection molded product, can be prevented.
Specifically, when the casting burr extrusion process is performed simultaneously with the molded product extrusion process or after the molded product extrusion process is started, a galling or runner abnormality has occurred in the runner portion of the injection molded product. By completing the process before the start of the molded product extrusion process, the occurrence of the above-described problems can be prevented.
More specifically, as a result of a test in which the casting burr extrusion process was performed at the same time as the molded product extrusion process, runner breakage occurred once in 30 times, whereas the molded burr extrusion process started with the molded burr extrusion process. By completing the process up to this point, it was possible to eliminate the trouble caused by the runner breakage.

With the above-described configuration, the molten metal detection sensor 43 is disposed around the pressure reducing valves 21 and 22. Therefore, even when the pressure reducing valve structure becomes large and complicated, the flatness of the pressure reducing valves 21 and 22 in mold matching Can be easily secured. Further, since it is not necessary to position the pressure reducing valves 21 and 22 so that the molten metal does not flow in the vicinity of the exhaust valve 24, it becomes easier to ensure the flatness of the pressure reducing valves 21 and 22 in the mold alignment.
Further, by adopting a configuration in which the molten metal can flow into the mating portions of the pressure reducing valves 21 and 22, mold distortion occurs in the entire mold due to a temperature difference generated between the cavity 10a portion into which the high-temperature molten metal flows, Even if the width of the mating portion of the pressure reducing valves 21 and 22 is changed, the injection molding is not affected, and problems such as hot water spraying can be prevented.

Sectional drawing before the injection molding which shows the vacuum die-casting apparatus which concerns on this invention. Sectional drawing at the time of injection molding which similarly shows a vacuum die-casting apparatus. The expanded sectional view before the injection | emission process which shows the pressure-reduction valve | bulb part of a vacuum die-casting apparatus. The expanded sectional view at the time of an injection process which similarly shows a pressure-reduction valve part. The expanded sectional view at the time of a mold opening process which shows a pressure-reducing valve part similarly. The expanded sectional view at the time of a casting burr | flash extrusion process which shows a pressure-reduction valve part similarly. Sectional drawing which shows the vacuum die-casting apparatus based on a prior art.

DESCRIPTION OF SYMBOLS 10 Vacuum die casting apparatus 10a Cavity 11 Fixed mold 12 Movable mold 13 Injection molded product extrusion apparatus 21 Fixed mold side pressure reducing valve 22 Movable mold side pressure reducing valve 24 Exhaust valve 27 Fixed mold side spacer 28 Movable mold side spacer 29 Casting burr extrusion apparatus 40 Depressurization Equipment 43 Molten metal detection sensor

Claims (5)

A mold that includes a fixed mold and a movable mold that is closely spaced from the fixed mold, and a cavity is formed between the fixed mold and the movable mold;
A pressure reducing valve provided in the mold for reducing the pressure in the cavity;
A decompression device for controlling decompression by the decompression valve;
A molten metal detection sensor disposed on the pressure reducing valve and connected to the pressure reducing device,
After decompressing the cavity with the decompression valve and the decompressor, the molten metal is injection molded into the cavity,
A vacuum die casting apparatus for controlling the opening of the pressure reducing valve by the pressure reducing device based on the detection of the molten metal by the molten metal detection sensor;
The pressure reducing valve is attached with a spacer interposed between the mold and the die.
A vacuum die casting apparatus characterized by that. The pressure reducing valve is
A fixed mold side pressure reducing valve disposed in the fixed mold;
A movable type pressure reducing valve disposed in the movable type,
When performing injection molding by the vacuum die casting apparatus,
A gap through which the molten metal can flow is formed at a joint portion between the fixed mold side pressure reducing valve and the movable mold side pressure reducing valve.
The vacuum die casting apparatus according to claim 1, wherein: The movable mold is provided with an injection molded product extrusion device,
The movable mold side pressure reducing valve portion of the movable mold is equipped with a casting burr extrusion device that is driven separately from the injection molded product extrusion device.
The vacuum die casting apparatus according to claim 2, wherein A pressure reducing valve provided in the mold with a spacer interposed between the mold and a cavity formed by a mold composed of a fixed mold and a movable mold contacting the fixed mold; and Then, after the pressure is reduced by the pressure reducing device, the molten metal is injection-molded into the cavity, and at the same time, based on the detection of the molten metal by the molten metal detection sensor connected to the pressure reducing device and disposed in the pressure reducing valve, the pressure reducing device An injection process for controlling the opening of the pressure reducing valve; and
A mold opening step for allowing the injection mold to be taken out of the fixed mold by separating the movable mold from the fixed mold;
Casting generated in a gap between the movable mold side pressure reducing valve and the fixed mold side pressure reducing valve disposed in the fixed mold by a casting burr extrusion device provided in the movable mold side pressure reducing valve portion of the movable mold. Extruding burrs, casting burr extrusion process,
The injection mold product is extruded by an injection molding product extrusion device provided in the movable mold, and a molded product extrusion step.
A vacuum die casting method characterized by the above. The casting burr extrusion process is completed by the time the molded product extrusion process starts,
The vacuum die casting method according to claim 4, wherein:

Images