WO2014147892A1

WO2014147892A1 - Casting device

Info

Publication number: WO2014147892A1
Application number: PCT/JP2013/082182
Authority: WO
Inventors: 佐々木　寛人; 三吉　博晃; 晴生明本
Original assignee: 宇部興産機械株式会社
Priority date: 2013-03-21
Filing date: 2013-11-29
Publication date: 2014-09-25
Also published as: EP2977127A4; CN105073302B; CN105073302A; EP2977127A1; JP2014180696A; JP5527451B1; US20160045955A1; KR20150131384A

Abstract

This casting device comprises: dies (19, 21) that form a cavity (22) having an opening in the lower section thereof; a pressurizing chamber (10) that is arranged below the dies, contains molten metal (A), and forms a sealed space above the molten metal; a tubular stalk (18), the upper-end opening of which is in communication with the opening of the cavity, and the lower-end opening of which is immersed in the molten metal inside the pressurizing chamber; a pressurizing means (16) that pressurizes the inside of the pressurizing chamber by supplying a gas into the sealed space in the pressurizing chamber; a depressurizing means (32) that depressurizes the inside of the cavity by discharging a gas from the cavity; and a control device (33). When the molten metal is filled into the cavity from the pressurizing chamber, the control device pressurizes the inside of the pressurizing chamber by the pressurizing means until the molten metal reaches the opening of the cavity, and after the molten metal has reached the opening of the cavity, the control device depressurizes the inside of the cavity by the depressurizing means while continuing to pressurize the inside of the pressurizing chamber.

Description

Casting equipment

The present invention relates to a casting apparatus.

Conventionally, a casting apparatus for producing an aluminum composite product such as an aluminum wheel by low pressure casting or low / medium pressure casting is known. In this type of casting apparatus, the pressure in the pressurizing chamber is increased while the molten metal is contained in the pressurizing chamber (crucible), and the pressure in the cavity of the mold is evacuated. The melt is filled into the cavity from the pressurizing chamber through the stalk by the pressure difference between the pressurization and the vacuuming (Patent Document 1).

However, in the casting apparatus disclosed in Patent Document 1, since the gate piston pin is opened after the molten metal side is set to a positive pressure and the cavity side is set to a negative pressure, the molten metal splashes due to the pressure difference at the moment of opening. A hot water bath and a hot water boundary are generated. That is, there is a problem that the quality of the molded product is deteriorated.

JP-A-5-146864

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a casting apparatus capable of preventing the molten metal from splashing and improving the quality of the cast product.

The casting apparatus according to the present invention includes a mold, a pressurizing chamber, stalk, a pressurizing means, a decompressing means, and a control device. The mold forms a cavity having an opening below. The pressurizing chamber is disposed below the mold and accommodates the molten metal, and forms a sealed space above the molten metal. The stalk is formed in a cylindrical shape in which the upper end opening communicates with the cavity opening and the lower end opening is immersed in the molten metal in the pressurizing chamber. The pressurizing means supplies gas to the sealed space of the pressurizing chamber to pressurize the pressurizing chamber. The decompression means exhausts gas from the cavity and decompresses the inside of the cavity. When filling the melt from the pressurizing chamber to the cavity, the control device pressurizes the pressurizing chamber until the molten metal reaches the opening of the cavity, and pressurizes the pressurizing chamber after the molten metal reaches the opening of the cavity. , The inside of the cavity is decompressed by the decompression means.

According to the present invention, when filling the cavity from the pressurizing chamber, the pressurizing chamber is pressurized by the pressurizing means until the molten metal reaches the opening of the cavity, and after the molten metal reaches the opening of the cavity, While continuing the pressurization, the inside of the cavity is decompressed by the decompression means. According to the timing of such pressurization and decompression, the present invention can prevent the molten metal from splashing and improve the quality of the product.

It is the schematic which shows the casting apparatus which concerns on embodiment. It is a top view which shows the cavity 22 which concerns on embodiment. It is the schematic of the filling operation | movement which concerns on embodiment. It is the schematic of the filling operation | movement which concerns on embodiment. It is the schematic of the filling operation | movement which concerns on embodiment. It is the schematic of the filling operation | movement which concerns on embodiment. In the embodiment, the pressure P1 applied to the pressurizing chamber 10 from the pressurizing source 16 with the passage of time, the pressure P2 sucking the cavity 22 from the vacuum device 32, and the differential pressure P3 between these pressures P1, P2 (hereinafter referred to as filling differential pressure) It is a figure which shows the change of. It is a figure which shows the change of the pressure P1 applied to the pressurization chamber 10 from the pressurization source 16 in the comparative example, the pressure P2 which attracts | sucks the cavity 22 from the vacuum apparatus 32, and the filling differential pressure P3.

Hereinafter, a casting apparatus according to an embodiment will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic view showing a casting apparatus according to an embodiment. As shown in FIG. 1, the casting apparatus has a pressurizing chamber (crucible) 10 for pressurizing the molten metal A. A container 11 for holding the molten metal A is provided in the pressurizing chamber 10. The upper end opening of the pressurizing chamber 10 is closed by the fixing plate 12, and the inside of the pressurizing chamber 10 is a sealed space. A gas supply path 13 and a gas discharge path 14 communicate with the sealed space (pressurizing chamber 10). The gas supply path 13 is connected to a pressurization source 16 through a valve 15 and supplies an inert gas into the pressurization chamber 10. The gas discharge path 14 opens the pressurizing chamber 10 to the atmosphere via the valve 17.

At the center of the fixed plate 12, the upper end of a cylindrical stalk 18 having both ends opened is fixed. The lower end of the stalk 18 is immersed in the molten metal A in the pressurizing chamber 10. A fixed mold 19 is attached to the upper surface of the fixed plate 12. A movable mold 21 is mounted on the lower surface of the movable plate 20 configured to be movable upward with respect to the fixed mold 19. The fixed mold 19 and the movable mold 21 form a cavity 22 when the mold is closed. An opening 23 a is formed in a gate portion communicating with the cavity 22 at the center of the fixed mold 19, and an upper end portion of the stalk 18 is communicated with the opening 23 a. Further, a degassing passage 23b for extracting gas from the cavity 22 is connected to the fixed mold 19, and the molten metal A is prevented from entering the degassing passage 23b between the cavity 22 and the degassing passage 23b. A chill vent 23c is provided.

The movable mold 21 is provided with a gate seal pin 24, a center pressure pin 25, and a partial pressure pin 26. The gate seal pin 24 is configured to move forward and backward with respect to the opening 23a, and opens and closes the opening 23a. The gate seal pin 24 is formed in a substantially rod shape. The center pressurizing pin 25 is configured to be movable forward and backward with respect to the hot water puddle 27 communicating with the cavity 22 and pressurizes the cavity 22. The center pressurizing pin 25 is formed in a cylindrical shape surrounding the gate seal pin 24. The partial pressure pin 26 is configured to move forward and backward with respect to the hot water reservoir 28 communicating with the cavity 22 and pressurizes the cavity 22. The partial pressure pin 26 is formed in a substantially rod shape.

The upper ends of the gate seal pin 24 and the center pressurizing pin 25 are connected to a piston mechanism 29 as a driving means, and are configured to be vertically movable. Similarly, the partial pressurizing pins 26 are configured such that their upper ends are connected to a piston mechanism 30 as drive means, and can be moved up and down.

Further, as shown in FIG. 1, the casting apparatus has a vacuum device 32 and a controller 33 connected to the gas vent passage 23 b via a gas vent valve 31.

The vacuum device 32 discharges gas from the cavity 22 through the gas vent valve 31 and the gas vent passage 23b, and depressurizes the inside of the cavity 22. The vacuum device 32 includes a vacuum tank 321, a vacuum pump 322 that evacuates the vacuum tank 321, and a motor 323 that drives the vacuum pump 322.

The controller 33 pressurizes the inside of the pressurizing chamber 10 by controlling the valve 15 and the pressurizing source 16. The controller 33 controls the valve 17 to open the pressurizing chamber 10 to the atmosphere. The controller 33 controls the valve 31 and the vacuum device 32 to discharge the gas in the cavity 22 and depressurize the inside of the cavity 22. The controller 33 controls the piston mechanism 29 to open and close the opening 23 a by the gate seal pin 24. The controller 33 controls the

piston mechanisms

29 and 30 to pressurize the cavity 22 by the center pressurizing pin 25 and the partial pressurizing pin 26.

Next, the positions of the gate seal pin 24, the center pressure pin 25, and the partial pressure pin 26 with respect to the cavity 22 will be described with reference to FIG. FIG. 2 is a plan view showing the cavity 22. As shown in FIG. 2, the cavity 22 extends symmetrically in the X direction and the Y direction around the gate seal pin 24 and the center pressurizing pin 25. In the example shown in FIG. 2, six partial pressure pins 26 are provided near the end of the cavity 22.

Next, with reference to FIGS. 3A to 3D and FIG. 4, a filling operation for filling the cavity 22 with the melt A from the pressurizing chamber 10 will be described. 3A to 3D are schematic views of the filling operation. FIG. 4 shows the pressure P1 applied to the cavity 22 from the pressurizing source 16 over time, the pressure P2 sucking the cavity 22 from the vacuum device 32, and the differential pressure P3 (hereinafter referred to as filling differential pressure) of these pressures P1 and P2. It is a figure which shows a change. In the present embodiment, the filling operation is executed based on the elapsed time. For example, the time for the molten metal A to reach the opening 23a is measured in advance, and the filling operation is executed based on the measured time.

In the filling operation, first, as shown in FIG. 3A, the controller 33 opens the valve 15 at time t11. Then, the controller 33 supplies an inert gas from the pressurization source 16 to the sealed space of the pressurization chamber 10 via the gas supply path 13. Thereby, as shown in FIG. 4, the pressure P1 applied to the pressurization chamber 10 from the pressurization source 16 rises after the time t11. Therefore, as shown in FIG. 4, the filling differential pressure P3 rises, and the molten metal A rises.

Next, as shown in FIG. 3B, after the molten metal A reaches the opening 23 a of the cavity 22 at time t <b> 12, the controller 33 continues from the pressurizing source 16 through the gas supply path 13 to the pressurizing chamber 10. An inert gas is supplied to the enclosed space. Further, as shown in FIG. 3B, the controller 33 opens the valve 31 so that the cavity 22 and the vacuum tank 321 communicate with each other. Thereby, the gas in the cavity 22 is discharged to the vacuum tank 321 through the gas vent passage 23b. The fact that the molten metal A has reached the opening 23a of the cavity 22 may be detected by a sensor, or the time for the molten metal surface to reach the opening 23a at a predetermined pressure is measured in advance and managed by that time. Anyway.

3B, the pressure P1 applied to the cavity 22 from the pressurization source 16 continues to increase after time t12 as shown in FIG. However, due to the shape of the cavity 22, the increasing speed of the pressure P1 is not constant. Further, by the control shown in FIG. 3B, the degree of pressure reduction (vacuum) in the mold is increased by the discharge from the cavity 22 by the vacuum device 32. That is, as shown in FIG. 4, the pressure P2 applied to the cavity 22 decreases in the minus direction. By these pressures P1 and P2, the filling differential pressure P3 increases as shown in FIG.

Next, as shown in FIG. 3C, when the molten metal A is filled in the cavity 22 at time t13, the molten metal A rushes and solidifies into the chill vent 23c arranged around the cavity 22, and the filling process is completed. When the molten metal A has solidified in all the chill vents 23c, the controller 33 closes the valve 31 and stops the pressure reduction. However, the pressure from the pressurizing source 16 is maintained at a constant pressure, and the molten metal A in the cavity 22 is solidified under this pressure. At that time, the gate seal pin 24 is pushed down to close the opening 23a. Subsequently, as shown in FIG. 3D, the controller 33 opens the valve 17 to release the pressurizing chamber 10 to the atmosphere, and lowers the molten metal surface of the molten metal A in the stalk 18. At this time, as shown in FIG. 3D, the controller 33 may press down the center pressurizing pin 25 to pressurize the inside of the cavity 22 and further increase the pressure. Furthermore, you may make it use the pressurization by the partial pressurization pin 26 together. Further, the gate seal pin 24 and the center pressurizing pin 25 may have an integral structure. In this case, the gate seal pin 24 and the center pressurizing pin 25 are lowered by a single cylinder, and the gate closing and pressurizing are performed in a continuous operation. After the molten metal A in the cavity 22 is solidified, the movable mold 21 is raised and the product is taken out.

Here, the decompressed cavity 22 is sealed with the gate seal pin 24, the inside of the pressurizing chamber 10 is pressurized, the molten metal A is raised to a position directly below the gate seal pin 24, the gate seal pin 24 is opened, and the pressurization and depressurization are performed. In the method in which the molten metal A flows into the cavity 22 due to the pressure difference, the molten metal A enters the cavity 22 in the form of droplets, and a molten metal and a hot water boundary are generated in the molded product. On the other hand, in the present embodiment, in the state where the gate seal pin 24 is opened, the inside of the pressurizing chamber 10 is pressurized until the molten metal A reaches the opening 23a of the cavity 22 as described above. In addition to continuing the pressurization in the pressurizing chamber 10 after reaching the opening 23a of the cavity 22, the interior of the cavity 22 is gradually decompressed as shown in FIG. Thereby, the filling differential pressure P3 when the molten metal flows into the mold can be gradually increased. Therefore, this Embodiment can suppress the splash of the molten metal A, and can suppress generation | occurrence | production of the hot water bottle and hot water boundary of a molded article.

Further, in the present embodiment, the pressure in the cavity 22 is controlled by the vacuum device 32 and the pressurizing chamber 10. Therefore, compared with the case where a plurality of pressurizing chambers are provided and the pressure in the cavity 22 is controlled, this embodiment can have a simple structure. Further, as compared with the case where the pressure in the cavity 22 is controlled only by the pressurizing chamber 10, the present embodiment can suppress the load applied to the pressurizing chamber 10 and can maintain the airtightness of the pressurizing chamber 10. . For reference, FIG. 5 shows a pressure P1 applied to the cavity 22 from the pressurization source 16 with the passage of time, a pressure P2 of the cavity 22, and a differential pressure between these pressures P1 and P2 in a comparative example in which the vacuum device 32 is not used together. The change of P3 is shown. When the cavity 22 is not depressurized, as the molten metal A flows into the cavity 22 and the filling proceeds, the back pressure is generated in the remaining portion, and the back pressure is further compressed by the end of the filling, and the molten metal to the final filling portion is increased. Inhibits filling. Therefore, if this is to be solved only by pressurization of the pressurizing chamber, it is necessary to increase the applied pressure P1 as shown in FIG. However, increasing the pressure in a closed container having a high temperature system of 700 ° C. requires measures to reinforce the hermetic seal and reduce the thermal load. That is, in addition to the sealing material itself having heat resistance, it is necessary to take measures to suppress thermal expansion and thermal distortion of a sealing member such as a flange, for example, to provide a cooling circuit in the vicinity of the sealing portion. In addition to the expensive materials used, the equipment becomes complicated. Such a problem can be solved in this embodiment.

In the present embodiment, since the back pressure in the cavity 22 can be suppressed by the vacuum device 32, the fluidity of the molten metal A in the cavity 22 can be enhanced.

Although the embodiments of the invention have been described above, the present invention is not limited to these embodiments, and various modifications and additions can be made without departing from the spirit of the invention.

A ... Molten metal, 10 ... Pressurizing chamber, 11 ... Container, 12 ... Fixing plate, 13 ... Gas supply passage, 14 ... Gas discharge passage, 15 ... Valve, 16 ... Pressure source, 17 ... Valve, 18 ... Stoke, 19 DESCRIPTION OF SYMBOLS ... Fixed mold, 20 ... Movable plate, 21 ... Movable mold, 22 ... Cavity, 23a ... Opening, 23b ... Gas vent passage, 23c ... Chill vent, 24 ... Gate seal pin, 25 ... Center pressure pin, 26 ... Partial pressure pins, 27, 28 ...
29, 30 ... piston mechanism, 31 ... degassing valve, 32 ... vacuum device, 33 ... controller.

Claims

A mold for forming a cavity having an opening below;
A pressurizing chamber that is disposed below the mold and accommodates the molten metal and forms a sealed space above the molten metal;
A cylindrical stalk in which an upper end opening communicates with the opening of the cavity and a lower end opening is immersed in the molten metal in the pressurized chamber;
Pressurizing means for supplying gas to the sealed space of the pressurizing chamber to pressurize the pressurizing chamber;
A pressure reducing means for discharging gas from the cavity and decompressing the inside of the cavity;
When filling the cavity with the melt from the pressurizing chamber, the pressurizing means pressurizes the pressurizing chamber until the melt reaches the opening of the cavity, and after the molten metal reaches the opening of the cavity, the heating is performed. And a control device for reducing the pressure in the cavity by the pressure reducing means while continuing to pressurize the pressure chamber.
A gate seal pin configured to be movable forward and backward with respect to the opening and opening and closing the opening;
The casting apparatus according to claim 1, wherein the controller closes the opening with the gate seal pin after the molten metal is filled in the cavity.
3. The casting apparatus according to claim 1, further comprising a pressure pin configured to be capable of moving forward and backward with respect to the puddle communicating with the cavity and pressurizing the molten metal filled in the cavity. 4.