JPH0890202A - Vacuum casting mold - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a vacuum casting mold that can suppress pressure loss and shorten the gas venting time. [Structure] The gas venting runner 11 is provided with a cooling means 15, a height reducing means 18 partially, a bush 19 and a gas vent valve pin 24, or a gas vent valve pin 25 having a taper portion 26 at a lower portion. Or the degassing runner 11 is communicated with a portion of the runner 12 upstream of the shut pin 9.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a vacuum casting mold,
Especially, it relates to the degassing runner structure.

[0002]

2. Description of the Related Art Vacuum casting is performed, for example, in Japanese Patent Laid-Open No. 2-155.
It is known from Japanese Patent No. 557. There, the cavity in the mold is decompressed and evacuated through a degassing runner, the gate is opened, the molten metal in the molten metal dome is poured into the cavity, and after closing the gate, the inside of the cavity is pressurized with a pressure pin. Is pressed and solidified to obtain a product. In the conventional vacuum casting mold, in order to reduce the pressure loss when the molten metal in the cavity is pressurized by the pressure pin, the cross-section thickness of the degassing runner is made thin throughout the runner length.
The molten metal is quickly solidified in the degassing runner portion when pouring, so that the molten metal does not escape to the degassing runner when the pressure pin is pressed.

[0003]

However, since the cross-sectional thickness of the degassing runner is thin, there is a problem that it takes time to depressurize the cavity. An object of the present invention is to provide a vacuum casting mold that can reduce pressure loss and shorten cavity decompression time.

[0004]

Means for Solving the Problems The present invention for achieving the above object is as follows. (1) A vacuum casting mold having a degassing runner for depressurizing a cavity, wherein the degassing runner is provided with cooling means. (2) A vacuum casting mold having a degassing runner for depressurizing the cavity, wherein the passage height of the degassing runner is lower in the vicinity of the cavity than in other parts. (3) In a vacuum casting mold equipped with a gas venting runner for depressurizing a cavity, a bush having an inner vent hole communicating with the vent vent runner and an outer vent hole is formed in the upper die. A vacuum casting mold in which a gas vent valve pin is slidably inserted into the hole and the bush hole can be opened and closed. (4) In a vacuum casting mold equipped with a gas vent runner for decompressing a cavity, a gas vent valve pin is slidably inserted into a hole formed in an upper die, and a hole is provided inside the gas vent valve pin to provide a gas vent passage. In addition, the vacuum casting mold is provided with a taper portion that engages with a recess provided in the lower die, at the bottom of the gas vent valve pin. (5) A vacuum casting mold provided with a gas venting runner for depressurizing a cavity, wherein the gas venting runner is placed in communication with a portion of the runner closer to the gate side than the shut pin.

[0005]

In the above (1), since the molten metal that has entered the degassing runner is rapidly solidified by the cooling means, when the molten metal in the cavity is pressurized by the pressing pin, the molten metal escapes to the degassing runner. Loss is suppressed. According to the above (2), since the passage height is reduced only in the vicinity of the cavity of the degassing runner, the air flow resistance at the time of degassing can be made small and the gas can be degassed in a short time.
In addition, the solidification of the molten metal is promoted at the part where the passage height is narrowed,
The pressure loss at the time of pressurizing the molten metal can be suppressed. According to the above (3), since the bush and the gas vent valve pin are provided in the gas vent passage, the gas vent passage can be enlarged and opened and closed by the gas vent valve pin. As a result, the gas vent passage can be opened to reduce the pressure in a short time during vacuuming, and the gas vent passage can be closed to increase the pressurization loss during pressurization. According to the above (4), in the bush and degassing valve pin system, the degassing passage is formed in the degassing valve pin, so that the cross sectional area of the degassing passage is large and the degassing time can be shortened. Further, since the lower end of the bush is tapered so that the molten metal is completely cut off at the cavity outlet, the pressure loss can be suppressed. According to (5) above, the degassing runner is provided so as to communicate with the portion of the runner closer to the gate side than the shut pin, so when the shut pin is closed and the molten metal in the cavity is pressurized with the pressure pin. In addition, the applied pressure is blocked by the shut pin and is not transmitted to the degassing runner, so there is no pressure loss. Further, since the pressure applied by the pressurizing pin is not transmitted, the passage cross-sectional area of the degassing runner can be made large and the vacuuming time can be shortened.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration common to all the embodiments of the present invention. FIGS. 2 and 3 show the first embodiment of the present invention, FIGS. 4 and 5 show the second embodiment of the present invention, and FIG. 7 and 8 illustrate the third embodiment of the present invention, FIGS. 9 and 10 illustrate the fourth embodiment of the present invention, and FIG. 11 illustrates the fifth embodiment of the present invention. Components common to all the embodiments are given the same reference numerals throughout the embodiments.

First, the structure and operation common to all the embodiments of the present invention will be described with reference to FIG. In FIG. 1, a casting cavity 3 is formed between an upper mold 1 and a lower mold 2,
Is lowered to the lower mold 2 and the mold is closed, the cavity 3 is sealed. A molten metal dome 4 movable relative to the upper mold 1 is lowered with respect to the upper mold 1, and a gate 5 formed at the lower end of the molten metal dome 4 closes the runner 12. On the other hand, a metal melt (for example, aluminum alloy melt) is placed in the melt holding furnace 7.
6 is held, and the molten metal 6 is pushed up into the molten metal dome 4 by adjusting the air pressure from the pressure port 8. The cavity 3 is depressurized with the gate 5 closed,
It is evacuated. A vacuum pump (not shown) is connected to the suction port 10, and air in the cavity 3 is evacuated through the gas vent runner 11 and the gas vent passage 14. After the cavity 3 is evacuated, the gate 5 is opened, and the molten metal in the molten metal dome 4 flows into the cavity 3 at a high speed due to the pressure difference between the pressure in the molten metal dome 4 and the vacuum in the cavity 3. Since the inside of the cavity 3 is vacuum, air is not entrained by the molten metal. When the cavity 3 is filled with the molten metal, the shut pin 9 closes the runner 12 and shuts off the cavity 3 and the molten metal dome 4. Then press pin 1
3 is pressed into the cavity 3 to pressurize the molten metal before solidification. Then, the suction from the suction port 10 and the pressure from the pressure port 8 are released. As a result, the molten metal in the molten metal dome 4 returns to the molten metal holding furnace 7. The molten metal in the cavity 3 solidifies over time. When the solidification is completed, the mold is opened and the cast product is taken out from the molds 1 and 2.

If the passage cross-sectional area of the degassing runner 11 is small, it takes too much time to degas the cavity 3 into a vacuum, and if the passage cross-sectional area is large, the pressurizing pin 13 is used.
There is a problem that when the molten metal in the cavity is pressurized, the molten metal escapes into the degassing runner 11 and a pressure loss occurs. The present invention is to prevent this. Next, the configuration and operation peculiar to each embodiment of the present invention will be described.

In the first embodiment of the present invention, as shown in FIGS. 2 and 3, the cooling means 15 is provided in a portion of the degassing runner 11 close to the cavity 3, and preferably in the lower mold 2.
Is provided. The cooling means 15 has, for example, an outer pipe 16 and an inner pipe 17, and sends the cooling water from the inner pipe 17 to flow through the space between the inner pipe 17 and the outer pipe 16 so as to discharge the degassing runner 11. It is designed to cool the nearby mold part. By the cooling by the cooling means 15, when the molten metal is filled in the cavity 3, the molten metal that enters the degassing runner 11 is rapidly solidified, and when the molten metal in the cavity 3 is pressurized by the pressure pin 13. It is possible to prevent the molten metal from escaping into the degassing runner 11. Further, since the cooling means 15 is provided in the degassing runner 11 to accelerate the solidification of the molten metal in the degassing runner 11, the pressure loss problem is unlikely to occur even if the passage cross-sectional area of the degassing runner 11 is increased. , Degassing runner 1
It becomes possible to increase the passage cross-sectional area of 1, and by doing so, the air flow resistance during degassing can be reduced,
The degassing time can be shortened.

In the second embodiment of the present invention, as shown in FIGS. 4 and 5, the height of the cross section of the passage is close to the cavity 3 in the degassing runner 11 as compared with other runner portions. A height reducing means 18 for lowering the height is provided. The lowered height is set to a height at which the molten metal can be rapidly solidified, and the degassing runner 1
The height is about 2 mm, although the height varies depending on the position of 1, the width (for example, 10 mm), and the like. The height of the degassing runner 11 in other portions is about 5 to 10 mm.
When the cavity 3 is filled with the molten metal, the molten metal entering the degassing runner 11 quickly solidifies at the portion where the height is lowered. Therefore, when the molten metal in the cavity 3 is pressurized by the pressure pin 13, it is possible to prevent the molten metal from escaping into the degassing runner 11 and suppress the pressure loss. And the degassing runner 1 is reduced by the pressure loss.
It is allowed to increase the passage cross section of the portion other than the height reduced portion of 1, and by increasing it, the air resistance at the time of degassing can be reduced and the degassing time can be shortened.

In the third embodiment of the present invention, as shown in FIGS. 6, 7 and 8, the upper mold 1 is provided with a bush 19 and a gas vent valve pin 24 in communication with the gas vent runner 11. The bush 19 has a passage hole 20 communicating with the degassing runner 11 on the inner side, and the bush 19 and the upper mold 1 on the outer side.
And a depressurization passage 21 formed between and. The depressurizing passage 21 is formed through a groove 23 formed on the upper and lower surfaces of a flange formed at the upper end of the bush 19 and a passage 14 formed between the upper mold 1 and the pin 24 above the bush 19. The upper mold 1 is communicated with the decompression chamber, and the suction chamber 10 is further connected to the vacuum pump. The wall of the bush 19 is provided with a hole 22 that connects the inner communication hole 20 and the outer pressure reducing passage 21. The gas vent valve pin 24 is slidably inserted in the bush 19,
Open and close the hole 22. The vertical movement of the degassing valve pin 24 is performed by the drive cylinder 31. In operation, with the gate 5 closed, the gas vent valve pin 24 rises to open the hole 22 and depressurize the cavity 3 to a vacuum. Then, the degassing valve pin 24 descends and the hole 22
To close the cavity 3. Then, gate 5
Open and introduce the molten metal into the cavity 3. Pressure pin 13
Is activated to pressurize the molten metal in the cavity. At this time, since the hole 22 is closed, the pressure loss is suppressed. on the other hand,
Since the gas vent passage can be largely provided inside and outside the bush 19, the air resistance can be reduced and the gas vent time can be shortened.

In the fourth embodiment of the present invention, as shown in FIGS. 9 and 10, the gas vent valve pin 25 is slidably inserted into the hole formed in the upper mold 1 so as to communicate with the gas vent runner 11. Has been done. The gas vent valve pin 25 has a lower end opened and an upper end that communicates with a decompression chamber in the upper mold 1 through a hole 27 and extends vertically.
Are formed. A taper portion 26 tapering downward is formed at the lower end of the gas vent valve pin 25, and a recess having a tapered side surface 28 is formed in the lower mold 2, so that the gas vent valve pin 25 descends. When the taper portion 26 is engaged with the taper 28 of the lower die recess, the gas vent passage 32 is closed, and when the pin 25 is lifted, the gas vent passage 32 is opened. The vertical movement of the degassing valve pin 25 is performed by the drive cylinder 29. For operation,
Gas vent valve pin 2 with gate 5 closed
5 rises to open the degassing passage 32, decompressing the cavity 3 to a vacuum. Next, the gas vent valve pin 25 descends to close the gas vent passage 32 and seal the cavity 3. Then, open the gate 5 and fill the molten metal into the cavity 3.
To be introduced. The pressurizing pin 13 is operated to pressurize the molten metal in the cavity. At this time, since the gas vent passage 32 is closed, the pressure loss is suppressed. On the other hand, the gas vent passage 32
Since it can be formed large in the pin, the air resistance can be reduced and the degassing time can be shortened.

In the fifth embodiment of the present invention, as shown in FIG. 11, the degassing runner 11 is arranged in communication with a portion of the runner 12 which is closer to the gate 5 than the shut pin 9 is. Reference numeral 30 denotes a gas vent valve pin having the same structure as the gas vent valve pin 24 or 25 described above. Regarding the operation, after the gate 5 is opened and the molten metal is poured from the molten metal dome 4 into the cavity 3, the shut pin 9 closes the runner 12. Next, the molten metal in the cavity is pressurized by the pressure pin 13, but since the shut pin 9 closes the runner 12, the pressurizing force of the pressure pin 13 is not transmitted to the degassing runner 11 and there is no pressure loss. . on the other hand,
The degassing runner 11 has no limit on pressure loss,
It can be made large, the air resistance at the time of degassing can be made small, and the degassing time can be reduced.

[0014]

According to the first aspect of the present invention, the degassing runner is provided with the cooling means, so that the molten metal can be rapidly solidified in the degassing runner portion, and the pressure loss can be suppressed.
On the other hand, since the pressure loss can be suppressed, the passage cross-sectional area of the degassing runner can be increased and the air resistance can be reduced to shorten the degassing time. According to the second aspect, the degassing runner is squeezed in the portion close to the cavity, so that the molten metal can be rapidly solidified in that portion, and the pressure loss can be suppressed. In addition, the passage cross-sectional area of the degassing runner can be increased correspondingly, and the degassing time can be shortened. According to the third aspect, since the bush and the gas vent valve pin are provided in the gas vent passage, the cross sectional area of the gas vent passage can be increased and the gas vent valve pin can be opened and closed to shorten the gas vent time. Further, since the passage is closed by the gas vent valve pin, the pressure loss can be suppressed. According to the fourth aspect, since the gas vent passage is formed in the gas vent valve pin, it is possible to further increase the cross sectional area of the gas vent passage and further shorten the gas vent time. Also,
Since the lower end of the bush is tapered so that the molten metal is completely shut off in the vicinity of the cavity of the degassing runner, pressure loss can be suppressed. According to the fifth aspect, the degassing runner is communicated with a portion of the runner that is closer to the gate side than the shut pin, so that the pressurizing force due to the pressurizing pin does not affect the degassing runner and pressure loss can be prevented. In addition, since the cross-sectional area of the degassing runner can be increased regardless of the pressurization by the pressurizing pin, the degassing time can be shortened.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a vacuum casting mold common to all embodiments of the present invention.

FIG. 2 is a sectional view of a vacuum casting mold according to the first embodiment of the present invention.

FIG. 3 is a plan view of a vacuum casting mold according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a vacuum casting mold according to a second embodiment of the present invention.

FIG. 5 is a plan view of a vacuum casting mold according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a vacuum casting mold according to a third embodiment of the present invention.

FIG. 7 is a plan view of a vacuum casting mold according to a third embodiment of the present invention.

FIG. 8 is a perspective view of a bush of a vacuum casting mold according to a third embodiment of the present invention.

FIG. 9 is a sectional view of a vacuum casting mold according to a fourth embodiment of the present invention.

FIG. 10 is a plan view of a vacuum casting mold according to a fourth embodiment of the present invention.

FIG. 11 is a plan view of a vacuum casting mold according to a fifth embodiment of the present invention.

[Explanation of symbols]

 1 Upper Die 2 Lower Die 3 Cavity 5 Gate 9 Shut Pin 11 Gas Release Runner 12 Runner 13 Pressurizing Pin 15 Cooling Means 18 Height Reduction Means 19 Bushing 24 Gas Release Valve Pin 25 Gas Release Valve Pin 26 Tapered Part 30 Gas Release Valve Pin 32 Gas vent passage

Claims (5)

[Claims] 1. A vacuum casting mold comprising a gas venting runner for depressurizing a cavity, wherein the gas venting runner is provided with a cooling means. 2. A vacuum casting mold provided with a gas venting runner for depressurizing a cavity, wherein a passage height of the gas venting runner is set to be lower near a cavity than in other parts. . 3. A vacuum casting mold having a degassing runner for depressurizing a cavity, wherein a bush having an inner communicating with the degassing runner, an outer depressurizing passage, and a wall having a hole communicating the inside and the outside is provided in the upper mold. A vacuum casting mold which is inserted into the formed hole, and a gas vent valve pin is slidably inserted into the bush so that the hole of the bush can be opened and closed. 4. In a vacuum casting mold equipped with a gas venting runner for depressurizing a cavity, a gas vent valve pin is slidably inserted into a hole formed in an upper die, and a gas is provided by providing a hole inside the gas vent valve pin. With a passageway,
A vacuum casting mold characterized in that a taper portion that engages with a recess formed in the lower die is provided below the gas vent valve pin. 5. A vacuum casting mold equipped with a gas venting runner for decompressing a cavity, wherein the gas venting runner is placed in communication with a portion of the runner closer to the gate side than the shut pin. Mold.