JPH0159065B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to improvements in vacuum die-casting equipment, particularly in shut-off valves.

[Prior art]

Some vacuum die casting machines that can produce castings with fewer defects such as blowholes are equipped with a shut-off valve in the suction passage that uses a vacuum pump to exhaust the gas in the cavity and prevents the molten metal from spewing out. The valve operation timing is controlled by a timer
37897, etc.) or by detecting the molten metal with a temperature sensor (Japanese Utility Model Publication No. 14923/1983). In the conventional shut-off valve, for example, as shown in FIG. It was designed to open and close depending on the tip.

[Problem that the invention seeks to solve]

In such conventional technology, the tip of the shutter-off pin 4 supported by one mold (movable mold 2) comes into contact with the other mold (fixed mold 1) and blocks the suction passage 3, so that the molds are not matched. As a result, there was a risk that the shut-off by the shaft-off pin 4 would be incomplete, or that foreign matter such as fragments of cast flash would get in the abutting portion, resulting in incomplete shut-off. However,
These risks become greater as the area of the abutting portion of the tip of the shutoff pin 4 increases, so it is difficult to increase the opening area of the shutoff valve, and it is therefore difficult to vent a large amount of gas in a short period of time. The problem was that it became difficult.

The present invention solves this problem by improving the structure of the shutoff valve.

[Means for solving problems]

For this purpose, in the vacuum die casting apparatus according to the present invention, as shown in FIGS.
0 and the fixed mold, a movable mold 11 forming a cavity 12, an injection device 13 for filling the cavity 12 with molten metal under pressure, a vacuum tank 22 evacuated by a vacuum pump 23, and the cavity 12. In a vacuum die casting device comprising a suction passage 20 communicating with a vacuum tank 22, a second valve body 42 fixed to one of the molds 10, 11, and a second valve body 42 fixed to the other of the molds 10, 11. and a valve seat 4 that opens on the contact surface with the second valve body 42.
A first valve body 41 having an internal passage 43 formed at one end thereof, and a cylinder device 50 that is supported by the first valve body 41 and reciprocated to move the valve seat 43
a, a poppet valve 45 that comes into contact with and separates from the valve seat 43a, a position of the second valve body 42 facing the valve seat 43a, and a position that faces the valve seat 43a of the second valve body 42, and
A valve reservoir 46 formed between the valve body 41
and a shut-off valve 40 comprising a communication passage 46a formed on the abutting surfaces of the valve bodies 41 and 42 and communicating the valve reservoir 46 and the cavity 12.
is provided in the suction passage 20.

[Effect]

When the fixed mold 10 and the movable mold 11 are closed, both valve bodies 4
1 and 42 are in contact with each other, and the cavity 12 is connected to the vacuum tank 22 via a suction passage 20 in which a shutoff valve 40 is provided. Injection device 1
At the beginning of pressurized filling of the molten metal into the cavity 12 according to No. 3, the poppet valve 45 is separated from the valve seat 43a by the cylinder device 46, and the gas in the cavity 12 is discharged through the communication passage 46a of the shut-off valve 40 and the valve hot water. It is sucked out into the vacuum tank 22 through the suction passage 20, which includes a reservoir 46 and an internal passage 43. After checking when the pressurized filling of the molten metal progresses and the molten metal approaches the shut-off valve 40, the cylinder device 46 is operated by a timer or a temperature sensor, etc., and the poppet valve 45 is closed to the valve seat 43a.
This closes the shut-off valve 40 and prevents the molten metal from entering beyond the valve seat 43a.

〔Effect of the invention〕

According to the present invention, since the valve seat is formed in the first valve body and the poppet valve that comes into contact with and separates from the valve seat is supported, even if there is a misalignment between the fixed type and the movable type, the poppet valve and the valve seat can be easily removed. This will not affect the contact state of the valve seat and the poppet valve will not open more than necessary. Therefore, even if the diameters of the valve seat and poppet valve are increased, the contact between the valve seat and poppet valve will not be incomplete due to misalignment of the molds, and fragments of casting flash, etc. will not be able to get in between the two. There is also little risk of it getting into the space and creating a gap when making contact. As described above, according to the present invention, the opening area of the shut-off valve can be increased and the contact is perfect, so gas in the cavity can be completely vented, and the molten metal can be spouted to a position beyond the shut-off valve, which can prevent malfunctions. It cannot be the cause.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIGS. 1 and 2, a fixed main mold 10a and a fixed nested mold 10b fixed thereto.
A movable mold 1 consisting of a movable main mold 11a and a movable nested mold 11b can be opened and closed with respect to a fixed mold 10 consisting of a movable main mold 11a and a movable nested mold 11b.
1 is provided, and when both molds 10 and 11 are closed as shown in the figure, both nested molds 10b and 11b abut each other to form a cavity 12 having the same shape as the product therebetween. An injection device 13 consisting of a hot water supply sleeve 13a and an injection plunger 13b is provided at the lower part of the fixed mold 10, and the molten metal 18 supplied from the hot water supply port 13c is transferred to both nested molds 10b and 11.
It is designed to be pressurized and filled into the cavity 12 through a runner 14 formed on the contact surface of the lower part b. The movable mold 11 is provided with an extrusion rod 16a (only one is shown and the others are omitted) for extruding the product, a runner, and a feeder portion, and an extrusion plate 16 for operating the extrusion rod 16a.

The cavity 12 has both nested types 10b and 11b.
a suction runner 15 formed on the contact surface of the upper part, a shutoff valve 40 attached to the upper part of the fixed and movable molds 10 and 11, and a discharge pipe 21 in which a filter 25 and a first electromagnetic valve 24 are provided in series. It is linked to a vacuum tank 22 evacuated by a vacuum pump 23 through a suction passage 20 consisting of A cylinder device 50 that operates the shut-off valve 40 includes air pipes 27a and 27b, and a switching solenoid valve 2.
9 and an air tank 30 to which pressurized air is supplied by an air compressor 31 via an air pipe line 27.
is communicated with. The air tank 30 also communicates with the discharge pipe 21 between the first solenoid valve 24 and the filter 25 via an air passage 26 and a second solenoid valve 28 .

Next, there is the shutoff valve 4, which is the main part of the present invention.
Explain 0. As shown in Figures 1 and 3,
The valve body of the shut-off valve 40 consists of a first valve body 41 and a second valve body 42 fixed to the upper surfaces of fixed and movable nested molds 10b and 11b, respectively.When both molds 10 and 11 are closed, Both valve bodies 41 and 42 are in contact with each other. As shown in FIG. 3, an L-shaped internal passage 43 is formed in the first valve body 41, one end of which opens at the contact surface 41a with the second valve body 42, and the valve seat is slightly recessed around the abutment surface 41a. 43a is formed, and the other end forms a suction port 43b which is open on the upper surface and to which the discharge pipe 21 is connected. A valve reservoir 46 is formed on the contact surface 42a of the second valve body 42 with the first valve member 41 at a position facing the valve seat 43a, and this valve reservoir 46 is communicated with the suction runner 15. A communication path 46a is formed. Note that the valve reservoir 46 and the communication passage 46a may be formed on the first valve body 41 side.

As shown in FIG. 3, a fitting hole 41b is formed on the opposite side of the first valve body 41 from the contact surface 41a, and is coaxial with the valve seat 43a and has a larger diameter than the inner diameter of the valve seat 43a. The fitted guide member 44, which is attached by bolting or the like, slidably supports the stem 45b of the poppet valve 45 so that its head 45a can move toward and away from the valve seat 43a. Guide member 44 fitted and supported in fitting hole 41b
A filter 47 is sandwiched between the tip of the outer cylindrical portion 44a and the stepped portion 43c of the internal passage 43, and is formed by superposing a wire mesh 47a and a support plate 47b provided with a large number of holes. An internal passage 4 is provided in a part of the cylindrical portion 44a.
A notch 44b is provided to allow the parts 3 to communicate with each other.

The guide member 44 includes a cylinder body 51 of a cylinder device 50 that operates the shut-off valve 40.
is fixed. A piston 52 is airtightly fitted into the inner surface of a cylinder 51a formed in a cylinder body 51 via an O-ring 53.
The guide member 4 is fixed to the tip of the stem 45b of the guide member 4.
A spring 54 interposed between the poppet valve 45 and the poppet valve 45 urges the head 45a of the poppet valve 45 in the direction of abutting against the valve seat 43a. In the cylinder body 51,
Both ends of the cylinder 51a are connected to air pipes 27a, 2
2 connected to the aforementioned switching solenoid valve 29 via 7b.
Two ports 51b and 51c are provided.

Next, the operation of the vacuum die casting apparatus of this embodiment will be explained.

When the vacuum die-casting device is started, mold release agent is first sprayed and then mold clamping is started. At the same time, the second solenoid valve 28 is opened and pressurized air in the air tank 30 flows through the air pipe line 26 and the second solenoid valve 28. Suction port 43 via solenoid valve 28, filter 25 and discharge pipe 21
b into the shutoff valve 40. In this state, the pressurized air in the air tank 30 is also guided to the port 51b of the cylinder device 50 via the air pipe 27, the switching solenoid valve 29, and the air pipe 27a, so that the pressurized air is The valve seat 43a and the head 45a of the poppet valve 45 are separated by a large distance, and pressurized air from the suction port 43b connects the internal passage 43, the valve seat 43a, and the head 45.
The gap a is cleaned.

When the mold clamping is completed, as shown in FIGS. 1 and 3, both molds 10 and 11 and both valve bodies 41 and 42 come into contact with each other, and the head 4 of the poppet valve 45
5a is pushed back somewhat by the second valve member 42, resulting in the state shown by the two-dot chain line in FIG. Almost at the same time, the second solenoid valve 28 closes. Next, hot water supply port 13
The molten metal 18 is injected into the hot water supply sleeve 13a from c, the injection device 13 is operated, and pressure filling of the molten metal into the cavity 12 from the runner 14 is started. When the injection plunger 13b of the injection device 13 moves forward to close the hot water supply port 13c, a preset timer (not shown) is activated to open the first solenoid valve 24, and the gas in the cavity 12 is discharged to the suction runner 1.
5. Communication path 46a, valve reservoir 46, valve seat 43
is sucked and discharged into the vacuum tank 22 through the gap between the head 45a and the internal passage 43, the filter 47, the discharge pipe 21, the filter 25, and the first electromagnetic valve 24,
Injection of molten metal through the runner 14 into the reduced pressure cavity 12 is started. When the molten metal injected into the cavity 12 advances and approaches the shut-off valve 40 from the suction runner 15, a preset timer is activated to switch the switching solenoid valve 29, and the air tank 30 is connected to the port 51c of the cylinder device 50. Pressurized air of
The shutoff valve 40 is closed. In this state, injection of the molten metal into the cavity 12 is completed, and the portion up to the valve reservoir 46 is filled with the molten metal. The timing at which the timer is set to close the shut-off valve 40 is determined in advance through experiments, depending on the shape and dimensions of the cavity 12, the mounting positions of the runner 14 and the suction runner 15, and the like.

When pressurized filling of the molten metal into the cavity 12 is completed, the first solenoid valve 24 is closed by the timer, and at the same time, the switching solenoid valve 29 is switched to guide pressurized air to the port 51b of the cylinder device 50, and the poppet The head 45a of the valve 45 is pressed against the second valve body 42 side. If you open the mold in this state,
The product, runners, valve parts, etc. are movable nested type 11
The movable mold 11 is separated from the fixed mold 10 while attached to the b side, and at the mold opening limit, the extrusion plate 16 is activated by the eject timer, and the extrusion plate 16 is moved through the extrusion rod 16a (only the one in the valve reservoir part is shown and the others are omitted). Movable nesting type 11 for products, runners, and valve basins
Push out from b. Incidentally, while the eject timer is in operation, the piston 52 is reciprocated by the switching solenoid valve 29 to shake off the deposits on the poppet valve 45. Next, one cycle of processing is completed by taking out the product, etc.

As described above, the valve seat 43a is formed on the first valve body 41, and the poppet valve 45 having the head 45a that comes into contact with and separates from the valve seat 43a is also slidably supported on the first valve body 41. Even if there is a misalignment between the molds 10 and 11, the head 45a of the poppet valve 45
This does not affect the contact state of the valve seat 43a and the valve seat 43a even when both molds 10 and 11 are opened.
Since the gap between the poppet valve 45a and the head 45a of the poppet valve 45 is not opened more than necessary, there is little possibility that pieces of casting flash or the like will enter therebetween and prevent the shutoff valve 40 from closing.

In this embodiment, as shown in FIG.
A large diameter fitting hole 4 is provided in the valve body 41 and is coaxial with the valve seat 43a.
1b, to which the guide member 44 supporting the poppet valve 45 is bolted, and the first valve body 4
A filter is sandwiched between the two.
According to this structure, even if the contact between the valve seat 43a and the head 45a becomes incomplete, most of the molten metal will be filled and solidified on the side of the valve seat 43a rather than the filter 47, so that this hardened molten metal will be guided. By removing the member 44, it can be easily removed together with the filter 47 from the fitting hole 41b.

Further, in this embodiment, the valve seat 43a is formed in a planar shape perpendicular to the axis of the poppet valve 45, but the valve seat may be formed in a conical shape. Alternatively, as shown in FIG. 4, the valve seat 143a is cylindrical and the outer periphery of the head 145a of the poppet valve 145 is connected to the valve seat 143a.
Alternatively, the molten metal may be fitted to prevent the molten metal from flowing into the internal passage 143 side.

Furthermore, the mounting position of the shut-off valve 40 is not limited to the upper part as shown in this embodiment, but is located in the cavity 1.
Depending on the shape of 2, it may be provided on the side as shown by the two-dot chain line in FIG. Moreover, it may be provided at multiple locations.

Regarding the mounting positions of both valve bodies 41 and 42, contrary to this embodiment, it is also possible to implement the present invention by mounting the first valve body 41 in a movable type and the second valve body 42 in a fixed type. be.

[Brief explanation of drawings]

1 to 3 show an embodiment of a vacuum die-casting apparatus according to the present invention, in which FIG. 1 is an overall configuration diagram with main parts cut away, FIG. 2 is a cross-sectional view taken along the line -- in FIG. 1, and FIG. 4 is an enlarged sectional view of a main part, FIG. 4 is an enlarged sectional view of a modified part of a modified embodiment, and FIG. 5 is a sectional view showing an example of the prior art. Explanation of symbols, 10... Fixed type, 11... Movable type, 12... Cavity, 13... Injection device, 2
0... Suction passage, 22... Vacuum tank, 23...
Vacuum pump, 40...Shut-off valve, 41
...First valve body, 42...Second valve main body, 43...
Internal passage, 43a... Valve seat, 45... Poppet valve, 46... Valve reservoir, 46a... Communication path,
50...Cylinder device.

Claims (1)

[Claims] 1. A fixed mold, a movable mold that forms a cavity between the fixed mold, an injection device that fills the cavity with molten metal under pressure, a vacuum tank that is evacuated by a vacuum pump, and communication between the cavity and the vacuum tank. In the vacuum die casting apparatus, the second valve body is fixed to one of the molds, and the second valve body is fixed to the other of the molds.
a first valve body having an internal passage formed at one end with a valve seat that opens at a contact surface with the valve body; a poppet valve formed between a position of the second valve body facing the valve seat and the first valve body; and a valve reservoir formed on the abutting surface of both valve bodies. A shutoff valve consisting of a communication passage that communicates with the cavity.
A vacuum die-casting device characterized in that it is provided in the suction passage.