JPH0751266B2 - Mold degassing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a degassing device in a vacuum die casting mold for die casting aluminum or the like.

[Prior Art] Generally, the die-casting method is a method of press-fitting a molten metal into a metal mold at a high speed to produce a casting, and is known as a method of accurately mass-producing a thin-walled and complicated-shaped casting.

However, this method has a drawback that bubble cavities are easily generated in the casting due to various causes. In order to eliminate this drawback, a die for vacuum die casting has been proposed as shown in FIGS. 4 to 6 (for example, JP-A-60-250867).
Issue).

As shown in FIG. 4, the mold has a fixed mold 5 and a movable mold 6.
And abut each other to form the cavity 4. Further, a vacuum runner 3 for sucking and discharging the decomposition gas and the like generated in the cavity 4 is arranged in the cavity 4. As shown in FIG. 5, the vacuum runner 3 communicates with the vacuum exhaust passage 7 via the tip portion inside the sleeve 20 that slides and guides the cutoff pin 2. The vacuum exhaust passage 7 is connected to a vacuum suction device 8 (Fig. 4).

On the other hand, the movable die is provided with a sleeve 20 for slidingly guiding the cutoff pin 2. The cutoff pin 2 is
It slides in the sleeve 20 left and right, and operates when the inside of the cavity 4 is in a vacuum state or when decomposed gas generated in the cavity is discharged. Also, at the time of casting, the sixth
As shown in the figure, the vacuum runner 3 and the vacuum exhaust passage 7 are shut off by the tip 21 of the cutoff pin 2.
As described above, the cut-off pin 2 has a role of opening and closing between the vacuum runner 3 and the vacuum exhaust passage 7.

[Problems to be solved]

However, in the above-mentioned conventional die, as shown in FIGS. 5 and 6, the contact surface 51 of the fixed die 5 and the movable die 6 are fixed.
The contact surface 61 and the tip end surface 21 of the cutoff pin 2 are flush with each other. Therefore, the opening of the inlet surface 71 of the vacuum exhaust passage 7 is not blocked due to a slight mold opening at the time of injection of the molten metal, generation of burrs between the tip end surface 21 of the cutoff pin 2 and the vacuum exhaust passage 7, and the like. Be complete. Therefore, the degree of vacuum in the cavity 4 may decrease, and molten metal may flow into the vacuum exhaust passage 7 to prevent casting. Further, as shown in FIG. 6, molten metal directly contacts and welds to the sliding surface Y of the cutoff pin 2. Further, the molten metal penetrates into the sleeve 20, the burrs are bitten, and eventually the molten metal is welded. Therefore, casting may be hindered and the work may have to be interrupted.

The present invention has been made in view of the above conventional problems, and a mold degassing device capable of performing stable sliding of a cutoff pin without intrusion of molten metal into a sleeve or a vacuum exhaust passage. It is intended to provide.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention provides a fixed die and a movable movable die that abuts with the fixed die to form a cavity, with abutting surfaces abutting against each other.
A vacuum runner communicating with the cavity, a sleeve as a cut-off pin sliding hole disposed through the mold above the vacuum runner, and a cut-off pin sliding in the sleeve; A die for vacuum die casting having a vacuum exhaust passage communicating with an opening in a lateral direction of the sleeve, wherein a concave gas passage portion is provided on an abutting surface of the die facing the die provided with the sleeve, and the fixing is performed. When the die and the movable die are brought into contact with each other, an upper end portion of the concave gas passage portion forms a communication port that communicates with the sleeve, and a lower end portion of the concave gas passage portion communicates with the vacuum runner. A communication port is formed, and both of the communication ports are separated by a wall portion below the contact surface opening of the sleeve, and the tip end of the cutoff pin faces each other during casting. The molten metal that has risen from the vacuum runner is prevented as well as preventing the molten metal from entering the sleeve by closing the communication port with the gas passage portion that is in contact with the contact surface of the mold and communicates with the sleeve. A degassing device for a vacuum die casting mold, characterized in that it is configured to stay and solidify in a concave gas passage.

Further, the sleeve is normally provided in a movable type and the gas passage portion is provided in a fixed type, but the arrangement may be reversed.

[Action and effect]

Since the die according to the present invention is configured as described above, during casting, the cut-off pin advances in the sleeve, the tip end portion of which comes into contact with the opposing die, and the gas passage portion communicating with the sleeve. Close the communication port with. Therefore, the sleeve and the concave gas passage portion are shut off from each other.

That is, the tip of the cut-off pin separates between the one die on the side where the sleeve is provided and the opposing die that faces the one die. This means that there is a break in the abutment surface between one die and the other opposing die (see FIG. 2).

Therefore, the molten metal rising in the vacuum runner enters the concave gas passage portion, but stays and solidifies there. Therefore, the molten metal does not enter the sleeve.

Therefore, when the mold and the counter mold are released from each other after casting, the solidified metal in the concave gas passage portion easily separates from the height on the side where the sleeve is provided.

Therefore, unlike the conventional case, burrs are not caught in the sleeve and molten metal is not welded to the sleeve and the cutoff pin.

On the other hand, during vacuum evacuation, that is, when the inside of the cavity is evacuated or when decomposed gas generated in the cavity is discharged, the cutoff pin retracts inside the sleeve,
The tip opening of the sleeve is opened (see FIG. 1).

As a result, the passage between the vacuum runner and the vacuum exhaust passage is opened. Therefore, the gas remaining in the vacuum munner and the cavity is
The gas is discharged to the outside of the mold by a vacuum device through the concave gas passage and the sleeve.

During vacuum evacuation, even if foreign matter in the cavity or vacuum runner tries to be sucked toward the sleeve, the foreign matter collides with the wall surface of the concave gas passage portion and falls. Therefore, such foreign matter does not enter the sleeve or the vacuum device and damage these and the cutoff pin.

Therefore, it is possible to perform stable sliding of the cutoff pin.

〔Example〕

The mold according to this example will be described with reference to FIGS. 1 to 3.

That is, the mold of this example, as shown in FIG. 1 and FIG.
A fixed die 4, a slidable movable die 6 that contacts the fixed die 5 to form a cavity (not shown), a sleeve 20 that penetrates through the movable die 6, and the inside of the sleeve 20. A cut-off pin 2 that slides along the vacuum runner 3, a vacuum runner 3 that communicates with the cavity, and a vacuum exhaust passage 7 that communicates with the opening at approximately the center of the sleeve 20.

Further, in the mold, the gas passage portion 1 communicating with the vacuum exhaust passage 7 and the tip end opening portion 203 of the sleeve 20 and the upper end opening portion 31 of the vacuum runner 3 is connected to the movable die 6 of the fixed die 5. It is arranged on the contact surface 51 for contact with.

That is, the gas passage portion 1 is arranged at a position where the tip end portion 22 of the cutoff pin 2 abuts. Further, as shown in FIG. 3, the gas passage portion 1 has a substantially rectangular cross-sectional shape, and the upper end portion 11 has a tip opening portion 203 in the sleeve 20.
Form a communication port that communicates with.

On the other hand, the lower end portion 12 of the gas passage portion 1 forms a communication port communicating with the upper end opening portion 31 of the vacuum runner 3. The gas passage portion 1 faces a contact surface 61 of the movable die 6 with the fixed die 5 at a substantially central portion thereof.

Further, each communication port is a wall portion 6a below the tip opening portion of the sleeve 20.
Separated by.

Since the mold of the present invention is configured as described above, it has the following effects.

First, in the case of casting a molten metal such as aluminum in the cavity, as shown in FIGS. 2 and 3,
The passage between the vacuum runner 3 and the vacuum exhaust passage 7 is cut off. That is, the cutoff pin 2 advances in the sleeve 20 in the direction A, and the tip 22 of the cutoff pin 2 contacts the fixed die 5.

Then, the sleeve 20 is sealed by the cutoff pin 2 in the front end opening portion 203 of the sleeve 20. As a result, the passage that connects the upper end portion 11 of the gas passage portion 1 and the vacuum exhaust passage 7 is blocked.

Therefore, the inside of the cavity is airtight. When viewed from the sleeve 20 side, as shown in FIG. 3, the tip end 22 of the cutoff pin 2 closes the upper end 11 of the gas passage 1. Then, the molten metal is cast in a vacuum state in the cavity.

Next, the decomposition gas generated in the cavity after the above casting is completed, and the inside of the vacuum runner 3 and the gas passage 1
The case of discharging the gas remaining inside will be described.

As shown in FIG. 1, the cutoff pin 2 is a sleeve.
The inside of 20 moves in the B direction, and the tip 22 moves to the E position. As a result, the tip end opening portion 203 of the sleeve 20 is opened.

Then, decomposed gas in the cavity, vacuum runner
3. The gas remaining in the gas passage portion 1 is sucked in the D direction from the C direction. Then, it is discharged out of the mold through the vacuum exhaust passage 7. At the time of discharging, the gas is sucked through the vacuum runner 3, the gas passage portion 1, and the vacuum exhaust passage 7 by a vacuum device (not shown) connected to the vacuum exhaust passage 7.

Further, in the mold of this example, the gas passage portion 1 is fixed to the fixed mold 5
Is disposed on the contact surface 51 with the movable mold 6. Therefore, the vacuum runner 3 and the vacuum exhaust passage 7 are communicated with each other through the gas passage portion 1. Therefore, the molten metal stays in the gas passage portion 1 and does not come into contact with the cutoff pin 2 or enter the sleeve 20. Further, the gas remaining in the gas passage portion 1 and the like is exhausted to the outside through the vacuum exhaust passage 7. Therefore, no gas remains in the vacuum exhaust passage 7 and the sleeve 20.

Therefore, according to this example, the cut-off pin can be stably slid without the molten metal entering the sleeve 20 and the vacuum exhaust passage 7 and welding.

[Brief description of drawings]

1 to 3 show a mold according to an embodiment, FIGS. 1 and 2 are sectional views thereof, FIG. 3 is a sectional view taken along the line YY of FIG. 2, and FIGS. FIG. 6 shows a conventional mold, FIG. 5 is a sectional view of a mold assembling apparatus, and FIGS. 5 and 6 are sectional views of the mold. 1 …… Gas passage, 11 …… Upper end, 12 …… Lower end, 2 …… Cutoff pin, 20 …… Sleeve, 3 …… Vacuum runner,
31 …… Top opening, 5 …… Fixed type, 51 …… Abutting surface, 6 …… Movable type, 61 …… Abutting surface, 7 …… Vacuum exhaust passage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumio Kondo 1-1, Showa-cho, Kariya city, Aichi prefecture Nihon Denso Co., Ltd. (72) Inventor Hiromi Takagi 1-1-chome, Showa town, Kariya city, Aichi prefecture Nidec Incorporated (72) Inventor Seiji Iketani 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd. (56) Reference JP 62-151258 (JP, A) JP 61-38770 (JP) , A) Japanese Patent Sho 56-21504 (JP, B2) Actual Japanese Sho 60-19805 (JP, Y2)

Claims (1)

[Claims] 1. A vacuum mold runner, which is provided with a fixed die and a movable movable die that abuts against the fixed die and forms a cavity, and abuts against each other, and is in communication with the cavity. A sleeve serving as a cut-off pin sliding hole, which is arranged above the vacuum runner and penetrating one of the molds, a cut-off pin that slides inside the sleeve, and a vacuum exhaust that communicates with the side of the sleeve. A die for vacuum die casting having a passage, wherein a concave gas passage portion is provided on an abutment surface of the die facing the die provided with the sleeve, and the fixed die and the movable die are abutted to each other. At this time, an upper end of the concave gas passage portion forms a communication port communicating with the sleeve, and a lower end portion of the concave gas passage portion communicates with the vacuum runner. The two communication ports are separated by a wall below the contact surface opening of the sleeve, and the tip end of the cut-off pin contacts the contact surface of the opposing die during casting. The communication port with the gas passage portion communicating with the sleeve is closed to prevent the molten metal from entering the sleeve, and the molten metal rising from the vacuum runner is allowed to stay and solidify in the concave gas passage portion. A degassing device for a vacuum die casting mold, which is characterized in that it is configured.