JP5726672B2 - Molten metal supply device and molten metal supply method - Google Patents

Description

  The present invention relates to a molten metal supply apparatus and a molten metal supply method in vacuum die casting.

  Conventionally, a vacuum die casting method has been used in which the inside of the cavity is decompressed in order to prevent the occurrence of defects due to gas entrainment in the cavity. For example, Patent Document 1 describes a casting method using a general vacuum die casting.

  In this casting method, the molten metal is poured into the plunger sleeve and the plunger rod is moved at a low speed. After that, the molten metal reaches the gate to the cavity from the moment when the plunger tip blocks the hot water supply port (gate driving), and enters the cavity. Until the molten metal filling is started, vacuum suction of the cavity is performed.

  Patent Document 2 describes a hot water supply technique in vacuum die casting. In this hot water supply technology, sufficient vacuum suction time is secured to obtain a high degree of vacuum of the cavity required for molding a high-quality product. That is, a sealed chamber is configured to cover the ladle filled with the molten metal and the hot water inlet of the sleeve, and the ladle is tilted after a sufficient amount of time is evacuated to inject the hot water from the hot water inlet into the sleeve. I have to.

International Publication No. 08/088084 Japanese Patent No. 3900422

  However, according to the method of Patent Document 1, the vacuum suction of the cavity is performed until the gate is hit. Therefore, in order to increase the vacuum suction time in order to increase the vacuum degree of the cavity, the plunger rod It is necessary to slow down the gate speed by reducing the forward speed. Then, the molten metal temperature in the plunger sleeve continues to decrease for the delayed time.

  Further, the molten metal supplied into the plunger sleeve flows and spreads in the plunger sleeve, and the surface area is increased, so that the temperature lowers rapidly. For this reason, when the vacuum suction time is extended, the decrease in the molten metal temperature due to the extension becomes even more negligible. Therefore, it may be difficult to ensure a sufficient vacuum suction time.

  Further, according to the technique of Patent Document 2, the sealed chamber is configured after the molten metal is transported to the ladle disposed in the vicinity of the sleeve or the ladle filled with the molten metal is disposed in the vicinity of the sleeve. In addition, the molten metal comes into contact with air or the like, and the molten metal temperature is liable to decrease and the generation of oxides. In addition, since the sealed chamber that covers the ladle is configured and the sealed chamber is vacuum-sucked, the volume to be vacuumed is large and a large-scale vacuum device is required. Also, the casting cycle time is prolonged.

  An object of the present invention is to provide a simple molten metal supply apparatus and a molten metal supply method capable of spending an arbitrary time without hindrance to vacuum suction in vacuum die casting in view of the problems of the prior art.

The molten metal supply apparatus of the present invention includes an injection sleeve of a die casting apparatus, a ladle immersed in the molten metal in a molten metal holding furnace, containing the molten metal, and transferred to the injection sleeve, and the injection sleeve and the inside of the ladle The ladle includes a molten metal inlet / outlet provided at a lower end portion and an opening / closing means for opening / closing the molten metal inlet / outlet, and the molten metal passes through the molten metal inlet / outlet when immersed in the molten metal. The injection sleeve includes a hot water inlet to which the molten metal inlet / outlet is connected via a connection surface, and an airtight holding means for holding the connection portion between the molten metal inlet / outlet and the hot water inlet in an airtight manner. The molten metal in the ladle is supplied via the hot water supply port, and the airtight holding means includes a groove provided along the circumferential direction of the hot water supply port on the connection surface of the airtight holding means, and the groove Vacuum through the groove through Characterized in that it comprises a suction port for argument.

  In this configuration, when the ladle is immersed in the molten metal in the molten metal holding furnace and the molten metal inlet / outlet is opened, the molten metal flows into the ladle. Thereafter, when the molten metal inlet / outlet is closed, the molten metal is accommodated in the ladle. Thereafter, the molten metal inlet / outlet of the ladle is connected to the hot water inlet of the injection sleeve, and when the molten metal inlet / outlet is opened, the molten metal in the ladle is supplied into the sleeve.

  At that time, when the molten metal inlet / outlet port of the ladle is connected to the hot water supply port of the injection sleeve, the connecting portion can be held airtight by the airtight holding means. Therefore, before the molten metal inlet / outlet is opened and the molten metal is supplied into the injection sleeve, the inside of the injection sleeve can be vacuumed and depressurized with sufficient time. This eliminates the need to depressurize the injection sleeve after the molten metal is supplied into the injection sleeve, so that the molten metal can be used for injection by the injection sleeve without significantly reducing the temperature of the molten metal.

  Therefore, according to the present invention, an arbitrary time can be spent for vacuum suction without any trouble by a simple configuration.

  Furthermore, there is no need to allow the molten metal to come into contact with the outside air or to carry out extra pouring of the molten metal from when the molten metal is stored in the ladle to when it is delivered to the injection sleeve. It is possible to prevent the generation of oxide film, the oxide film entrainment, and the like, and the deterioration of the quality of the cast product can be prevented.

Moreover, because provided with a pressure reducing device for reducing the interior of the injection sleeve and ladle, before supplying the molten metal into the injection sleeve, since the inside of the injection sleeve and ladle can be depressurized, for the molten metal in the ladle It is possible to more effectively prevent a temperature drop and the generation of an oxide film.

  In addition, when the molten metal inlet / outlet is opened and molten metal is supplied into the injection sleeve, the ladle and the injection sleeve are connected by a decompression pipe, and when the pressure in the ladle and the injection sleeve match, A turbulent flow due to a pressure difference between the ladle and the injection sleeve can be prevented from flowing into the injection sleeve.

  In the present invention, the decompression device may include a regulator for making the decompression degree of the injection sleeve higher than the decompression degree of the ladle. According to this, before the molten metal is supplied into the injection sleeve, the pressure reduction in the injection sleeve and the ladle can be performed so that the pressure reduction degree of the injection sleeve is higher than the ladle. The supply rate of the molten metal can be improved, and the temperature drop of the molten metal can be more effectively suppressed.

Furthermore, in this invention, you may provide the cleaning unit which removes the molten metal adhering to the part connected to the said injection sleeve around the molten metal inlet / outlet of the said ladle. According to this, the quality of the molten metal supplied can be improved, and the quality of the cast product can be further improved.

The molten metal supply method of the present invention includes a housing step of immersing a ladle having a molten metal inlet / outlet at a lower portion in a molten metal in a molten metal holding furnace, and accommodating the molten metal in the ladle through the molten metal inlet / outlet, and the accommodating step Thereafter, the lower end portion of the ladle is brought into close contact with the connection surface to the injection sleeve, and the vacuum inlet / outlet of the groove provided in the connection surface is started along the circumferential direction of the hot water supply port. a connection step of connecting to the hot water outlet of the injection sleeve, after the connecting step, a depressurizing step of depressurizing the inside of the ladle and the injection sleeve, after the decompression process, in the ladle by opening the melt doorway And a supply step of supplying the molten metal into the injection sleeve. A cleaning process may be provided after the housing process and after the supplying process to remove the molten metal adhering to the portion connected to the injection sleeve around the molten metal inlet / outlet of the ladle.

  According to the molten metal supply method of the present invention, as in the case of the above-described molten metal supply apparatus, an arbitrary time can be used for vacuum suction without any trouble by a simple configuration. Further, it is possible to avoid the temperature drop, the generation of the oxide film, the entrainment of the oxide film, and the like in the molten metal supplied, and the deterioration of the quality of the cast product can be prevented.

It is a top view of the casting system concerning one embodiment of the present invention. It is sectional drawing which shows a mode when the injection sleeve and the ladle in the system of FIG. 1 are connected. It is sectional drawing of the connection part of the injection sleeve and a ladle in the system of FIG. It is a flowchart which shows the molten metal supply process in the system of FIG. It is a figure which shows the mode of the ladle etc. in the process of FIG. It is a figure which shows the structure for performing pressure reduction in the casting system which concerns on another embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a casting system according to an embodiment of the present invention.

  As shown in FIG. 1, the casting system 1 uniformly heats a die casting apparatus 2 for performing casting by vacuum die casting, an injection sleeve 3 for injecting molten metal into a cavity of the die casting apparatus 2, and a stored molten metal. A molten metal holding furnace 4, a ladle 5 which is immersed in the molten metal in the molten metal holding furnace 4, accommodates the molten metal and transports it to the injection sleeve 3, a transport robot 6 which transports the ladle 5, and a ladle 5 And a cleaning unit 7 for removing the molten metal adhering to the surface.

  The cleaning unit 7 has a function of removing the molten metal adhering to the ladle 5 with an air blow or a brush.

  FIG. 2 is a cross-sectional view showing a state when the ladle 5 is connected to the injection sleeve 3. As shown in FIG. 2, the ladle 5 includes a molten metal inlet / outlet 8 provided at a lower end portion and a rod valve 9 that opens and closes the molten metal inlet / outlet 8.

  The injection sleeve 3 presses the molten metal supplied into the injection sleeve 3, a hot water supply port 10 to which the molten metal inlet / outlet 8 is connected, an airtight holding means 11 for holding the connection portion between the molten metal inlet / outlet 8 and the hot water supply port 10 in an airtight manner. And a plunger 12 that injects into the cavity of the die casting apparatus 2.

  Pipes 13 and 14 for vacuum suction are connected to the inside of the injection sleeve 3 and the ladle 5, respectively. The pipes 13 and 14 are joined together and connected to the vacuum device 16 via the valve 15. Thereby, the inside of the injection sleeve 3 and the ladle 5 is vacuum-sucked by the vacuum device 16 and depressurized at the same depressurization degree. That is, the pressure reducing device is configured by the pipes 13 and 14, the valve 15, and the vacuum device 16.

  The injection sleeve 3 communicates with the cavity of the die casting apparatus 2. For this reason, when the injection sleeve 3 is depressurized by vacuum suction, the cavity is also depressurized at the same degree of depressurization.

  FIG. 3 is a cross-sectional view of the vicinity of the connection portion when the ladle 5 is connected to the injection sleeve 3. As shown in FIG. 3, the lower end portion of the ladle 5 has a conical shape, and a molten metal inlet / outlet 8 is provided at the distal end portion thereof. The molten metal inlet / outlet 8 is opened when the rod valve 9 is located at the upper open position U, and is closed when the rod valve 9 is located at the lower closed position D.

  The airtight holding means 11 is configured by a rectangular parallelepiped member 17 provided on the injection sleeve 3, and has a cylindrical through hole 18 adjacent to the hot water supply port 10, an upper side of the through hole 18, and an upper side. And a frustoconical connection surface 19 that is open to the front. The connection surface 19 has a shape adapted to the conical lower end of the ladle 5. That is, by bringing the lower end portion into close contact with the connection surface 19, the molten metal inlet / outlet 8 can be made to face the through hole 18.

  The connection surface 19 is provided with a groove 20 along the inner circumferential direction. The groove 20 is vacuum-sucked through a port 21 opened on the side surface of the member 17. Therefore, the molten metal inlet / outlet 8 of the ladle 5 is hermetically connected to the hot water inlet 10 of the injection sleeve 3 by bringing the lower end of the ladle 5 into close contact with the connection surface 19 and vacuuming the groove 20.

  FIG. 4 is a flowchart showing the molten metal supply process in the casting system 1, and FIG. 5 shows the state of the ladle 5 and the like in this process. The molten metal supply process is performed by the control unit of the casting system 1 via the transfer robot 6 or the like.

  When the molten metal supply process is started, first, an accommodating process for accommodating the molten metal in the ladle 5 is performed (step S1). That is, as shown in FIG. 5 (a), the ladle 5 is immersed in the molten metal in the molten metal holding furnace 4 with the molten metal inlet / outlet 8 opened by the transfer robot 6, and the molten metal is introduced into the ladle 5 through the molten metal inlet / outlet 8. Let it flow.

  At this time, since the inside of the ladle 5 is opened to atmospheric pressure, the molten metal flows into the ladle 5 through the molten metal inlet / outlet 8 by being immersed in the molten metal. After the inflow is completed, the molten metal inlet / outlet 8 is closed to complete the storage of the molten metal.

  Next, as shown in FIG. 5B, the ladle 5 is pulled up from the molten metal holding furnace 4 and moved to the cleaning position by the cleaning unit 7 (step S2). And the cleaning process which removes the molten metal adhering to the lower part of the ladle 5 is performed by the cleaning unit 7 (step S3). At this time, in particular, as shown in FIG. 5C, the molten metal 22 adhering to the portion connected to the injection sleeve 3 around the molten metal inlet / outlet 8 is removed.

  Next, the ladle 5 is moved to the position of the injection sleeve 3 (step S4). And the connection process which connects the ladle 5 to the injection sleeve 3 is performed like FIG.5 (d) (step S5). At this time, as shown in FIG. 3, the lower end of the ladle 5 is brought into close contact with the connection surface 19 of the airtight holding means 11, and vacuum suction of the groove 20 is started.

  Thereby, the molten metal inlet / outlet 8 is connected to the hot water inlet 10 of the injection sleeve 3 in an airtight state. During the connection, the vacuum suction of the groove 20 prevents the atmosphere from entering the injection sleeve 3 along the connection surface 19 as much as possible.

  Next, a depressurizing step for depressurizing the inside of the ladle 5 and the injection sleeve 3 is performed (step S6). That is, the valve 15 (FIG. 2) is opened, and the inside of the ladle 5 and the injection sleeve 3 is simultaneously vacuumed by the vacuum device 16. At this time, the inside of the ladle 5 and the injection sleeve 3 is depressurized at the same depressurization degree, and vacuum suction is performed until a predetermined depressurization degree is reached.

  Next, as shown in FIG. 5E, a supply process is performed in which the molten metal inlet / outlet 8 is opened and the molten metal in the ladle 5 is supplied into the injection sleeve 3 (step S7). The molten metal inlet / outlet 8 is opened by raising the rod valve 9 to the open position U shown in FIG.

  Next, the vacuum suction in the groove 20 of the airtight holding means 11 is released, and the ladle 5 is separated from the injection sleeve 3 and moved to the cleaning position by the cleaning unit 7 (step S8). And the cleaning process which removes the molten metal adhering to the lower part of the ladle 5 is performed by the cleaning unit 7 (step S9). At this time, in particular, as shown in FIG. 5 (f), the molten metal 22 adhering to the inside of the molten metal inlet / outlet 8 or the tip of the rod valve 9 is removed.

  Next, the ladle 5 is moved onto the molten metal holding furnace 4 and waits (step S10). Thereafter, until the end of the molten metal supply process (step S11), the process returns to the accommodation process of step S1, and the processes of steps S1 to S10 are repeated.

  According to the present embodiment, when the molten metal inlet / outlet 8 of the ladle 5 is connected to the hot water inlet 10 of the injection sleeve 3, the connecting portion is held airtight by the airtight holding means 11, so that the molten metal is injected into the injection sleeve 3. Before the supply, the inside of the injection sleeve 3 can be depressurized. For this reason, since it is not necessary to decompress the inside of the injection sleeve 3 after supplying the molten metal into the injection sleeve 3, it is possible to prevent the temperature of the supplied molten metal from being lowered as much as possible. Therefore, with a simple configuration, any time can be used for vacuum suction in the injection sleeve 3 without any problem.

  In addition, it is not necessary to allow the molten metal to come into contact with the outside air or to carry out extra pouring of the molten metal until the molten metal is stored in the ladle 5 and delivered to the injection sleeve 3. It is possible to avoid a decrease in temperature, generation of an oxide film, entrainment of an oxide film, and the like, thereby preventing a deterioration in quality of a cast product.

  Further, since the decompression device for decompressing the inside of the injection sleeve 3 and the ladle 5 is provided, the interior of the ladle 5 is reduced by decompressing the inside of the injection sleeve 3 and the ladle 5 before supplying the molten metal into the injection sleeve 3. Therefore, it is possible to more effectively prevent a temperature drop and an oxide film from occurring in the molten metal.

  When the molten metal inlet / outlet 8 is opened and molten metal is supplied into the injection sleeve 3, the ladle 5 and the injection sleeve 3 are connected by the pipes 13 and 14, and the pressure in the ladle 5 and the injection sleeve 3 is Therefore, the molten metal can be prevented from flowing into the injection sleeve 3 as a turbulent flow due to a pressure difference between the ladle 5 and the injection sleeve 3.

  Moreover, since the cleaning unit 7 for removing the molten metal adhering to the ladle 5 is provided, the quality of the supplied molten metal can be improved and the quality of the cast product can be further improved.

  FIG. 6 shows a configuration for depressurizing the injection sleeve 3 and the ladle 5 in a casting system 1 according to another embodiment of the present invention. In this configuration, instead of the valve 15 in the configuration of FIG. 2, a valve 23 and a regulator 25, and a valve 24 and a regulator 26 are provided in each of the pipes 13 and 14. Other points in the present embodiment are the same as those in the above-described embodiment shown in FIGS.

  According to the present embodiment, the operation of the regulators 25 and 26 can perform vacuum suction of the ladle 5 and the injection sleeve 3 so that the pressure reduction degree of the injection sleeve 3 is higher than the pressure reduction degree of the ladle 5. Therefore, in the pressure reducing step of step S6 described above, the pressure reduction degree of the injection sleeve 3 can be made higher than the pressure reduction degree of the ladle 5. Thereby, the supply speed of the molten metal from the ladle 5 in the supply process of step S7 into the injection sleeve 3 can be raised, and the temperature fall of a molten metal can be suppressed more effectively.

  The present invention is not limited to the above embodiment. For example, in the above, as the airtight holding means 11, the one having the connection surface 19 in close contact with the lower end portion of the ladle 5 and the vacuum sucked groove 20 is used, but instead, other airtight holding means, for example, An airtight holding means such as a metal seal or a gasket or a combination of these may be used.

  Further, in the above description, when the molten metal is accommodated in the ladle 5 in the accommodating step in step S1, the molten metal is introduced from the molten metal inlet / outlet 8 by opening the space in the ladle 5 to the atmosphere. In addition, the molten metal may be introduced from the molten metal inlet / outlet 8 by reducing the space in the ladle 5.

DESCRIPTION OF SYMBOLS 2 ... Die casting apparatus, 3 ... Injection sleeve, 4 ... Molten metal holding furnace, 5 ... Ladle, 7 ... Cleaning unit, 8 ... Molten metal inlet / outlet, 10 ... Hot water inlet, 11 ... Airtight holding means, 25, 26 ... Regulator.

Claims (5)

An injection sleeve of a die casting device;
A ladle immersed in the molten metal in the molten metal holding furnace, containing the molten metal and transferring it to the injection sleeve ;
A decompression device for decompressing the inside of the injection sleeve and the ladle ,
The ladle includes a molten metal inlet / outlet provided at a lower end portion and an opening / closing means for opening / closing the molten metal inlet / outlet, and accommodates the molten metal through the molten metal inlet / outlet when immersed in the molten metal,
The injection sleeve includes a hot water inlet to which the molten metal inlet / outlet is connected via a connection surface, and an airtight holding means for hermetically holding a connection portion between the molten metal inlet / outlet and the hot water inlet , through the hot water inlet. The melt in the ladle is supplied,
The airtight holding means includes a groove provided along the circumferential direction of the hot water supply port on the connection surface of the airtight holding means, and a suction port for vacuum suction of the groove through the groove. A molten metal supply device characterized by the above. The molten metal supply apparatus according to claim 1 , wherein the pressure reducing device includes a regulator for increasing a pressure reduction degree of the injection sleeve higher than a pressure reduction degree of the ladle. Melt supply device according to claim 1 or 2, characterized in that it comprises a cleaning unit for removing the molten metal adhering to the portion connected to the injection sleeve around the molten metal entrance of the ladle. A housing step of immersing a ladle having a molten metal inlet / outlet at a lower part in a molten metal in a molten metal holding furnace, and accommodating the molten metal in the ladle through the molten metal inlet / outlet;
After the housing step, the lower end of the ladle is brought into close contact with the connection surface to the injection sleeve of the die casting apparatus, and vacuum suction of a groove provided on the connection surface is started along the circumferential direction of the hot water inlet of the injection sleeve by a connecting step of connecting the melt entrance to the hot water outlet of the injection sleeve,
After the connecting step, a decompression step of decompressing the inside of the ladle and the injection sleeve;
A molten metal supply method comprising: a supply step of opening the molten metal inlet and outlet and supplying the molten metal in the ladle into the injection sleeve after the pressure reducing step. After said receiving step, and after the supplying step, according to claim 4, characterized in that it comprises a cleaning step of removing the molten metal adhering to the portion connected to the injection sleeve around the molten metal entrance of the ladle Molten metal supply method.

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