JPH027746B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a degassing device for a mold used in a molding machine such as a die-casting machine.

[Prior Art] Die casting has traditionally been widely used as a method for manufacturing precision products in large quantities, but it has sometimes been unsuitable for products where the integrity of the product is important, with no cavities inside.

The reason for this is that since the cavity is filled with molten metal at high speed and high pressure, the gas in the cavity may not be able to escape sufficiently and may mix with the molten metal and remain in the product as cavities.

In order to solve these inconveniences, the inventors of the present invention are able to reliably and easily remove a large amount of gas without being restricted by the casting product or mold, eliminate gas entrainment, and obtain a sound die-cast product. We have developed a gas venting device for molds.

The degassing device for molds that the present inventors have developed so far is JP-A No. 56-47257 (JP-A No. 59-Sho.
309, Patent No. 1275125), JP-A-56-47260 (JP-A-58-46387, Patent No. 1279898), JP-A-Sho
No. 57-1558 (Special Publication No. 58-51784, Patent No. 1317064)
) and Utility Model No. 76964 (1983)
There are devices described in publications such as No. 12121 and Utility Model Registration No. 1574018).

These devices perform injection with the discharge path leading from the mold cavity to the outside of the mold open by the action of a valve, and when the small mass of gas in the cavity has been exhausted through the gas discharge path, By applying the inertial force of the large-mass injected molten material that has advanced from inside the cavity directly to the valve, the valve is quickly moved and closed, directly blocking the gas exhaust path, and preventing the flow of gas from this gas exhaust path. It is designed to prevent the melt from flowing out and to ensure that gas inside the mold can be easily vented during injection.

However, these devices are structured so that a force in the valve opening direction is always applied to the valve by the action of a compression spring installed at the rear end of the valve, so during injection the molten metal flows at a speed of, for example, 40 m/sec. When the molten metal comes intermittently in the form of flakes at an extremely high speed, the valve closes once due to the inertia of the first molten metal, but the next moment when the molten metal stops coming for a moment, the valve closes once. The valve opens again under the action of the compression spring. In this way, when molten metal comes intermittently, the valve closes and opens several times. Therefore, if some of the molten metal reaches the valve seat when the valve is just open, some of the molten metal will forcefully enter the valve device and cause damage to the inside of the valve device and the valve seat. It adheres to and solidifies. As a result, the valve may not close properly or may stop moving.
Unless the valve device is disassembled and repaired or replaced with a new one, the valve device cannot be used and, of course, cannot achieve its original purpose of constantly discharging the gas in the mold cavity.

Of the conventional examples mentioned above, Japanese Patent Application Laid-Open No. 57-1558
In the case of the publication, first, before clamping the mold and injecting,
Reactive gas is supplied into the cavity of the mold through the gas venting valve that is open, and after replacing the air in the cavity that causes cavities in the injection product with the reactive gas as much as possible, the gas inside the cavity is replaced with the reactive gas. Special injection work is performed while vacuum suction is applied through the extraction valve.

In addition, the device disclosed in Japanese Utility Model Application Publication No. 57-76964 vacuums the inside of the cavity with the degassing valve open, and also supplies compressed air through the open valve after opening the mold to create a valve device. It is designed to blow away metal powder, etc. that has remained in nearby pipes to clean them.

However, in these technologies, as mentioned above, a compression spring is provided in the degassing valve device that constantly applies a force in the valve opening direction to the valve, so the valve cannot be opened while the valve is open. The valve does not close with a shock when setting the mold or spool into the mold, but as mentioned above, the valve that once closed due to the inertia of the molten metal during injection opens again due to the intermittent flow of the molten metal, and at that time, the molten metal There was a problem in which the valves stopped working after entering the equipment.

In order to eliminate this drawback, the inventors of the present invention have proposed Japanese Patent Application Laid-open No. 57-88962 (Japanese Patent Publication No.
1225117) and Utility Model Application Publication No. 106462/1983.

Among these devices, the mold degassing device described as an example in Japanese Patent Application Laid-Open No. 57-88962 has a degassing device for molds that can be used even at the mating surfaces of the fixed mold 1 and the movable mold, as shown in Fig. 4. It is provided near the terminal end of the gas vent groove 6 extending from a cavity provided on a certain dividing surface and at an extension line thereof. In this device, a spool 9 has a valve 7 slidably provided inside.
is provided movably in the sliding direction of the valve 7 by a cylinder 21 attached to the fixed mold 1 via a bracket 20. Reference numeral 8 denotes a detour passage extending from the middle of the gas vent groove 6 to the upper side of the valve head 7a of the valve 7, 12 a gas discharge port, and 44 a member 7e and spool attached to the rear end of the valve rod 7b. This is a tension spring installed between the top of 9 and the top of 9. Further, a part of the spool 9 located on the side of the member 7e has a through hole 9a,
A steel ball 17 that is pressed by a compression spring 16 in the through hole 9a and a push screw 18 for adjusting the spring force are provided. It is in contact with a small portion 7c formed on the upper outer circumference of the member 7e, and the member 77e and the valve 7 are pulled together by the action of the tension spring 44, thereby stopping the valve 7 from closing. and,
During injection, the gas in the cavity flows into the gas vent groove 6,
When the molten metal passes through the passage 8 and the spool 9 and is discharged from the discharge port 12, when the molten metal comes through the gas vent groove 6 and the inertial force of the molten metal acts on the valve head 7a, the valve 7 is closed by the steel ball 17. It overcomes the holding force and rises to close, and once it is closed, the tension spring 4
4 keeps the valve 7 closed.

Note that a return rod 42 is provided in a state of protruding from the side surface of the member 7e, passing through a hole 41 provided in the side surface of the spool 9. On the other hand, a stopper mechanism 43 is attached to a part of the inner surface of the bracket 20 so that its position can be adjusted in accordance with the position near the tip of the return rod 42. Then, when the valve 7 closes just before the end of the injection operation and the spool 9 is retracted after the mold is opened, the return rod 42 is connected to the stopper mechanism 43 while the spool 9 is retracting. This prevents only the valve 7 from moving back and allows the valve 7 to open.

On the other hand, when the molding equipment starts operating after being stopped for a long time, such as overnight or several hours, the mold and other parts are cooled down, and normal injection operations cannot be performed in this cooled state. If the molten metal cools down before it reaches every corner of the mold cavity, a normal product may not be produced, and some of the product may remain in the mold.

During injection molding, low-speed injection is performed at the initial stage of injection, followed by high-speed injection, but at the beginning of operation, usually 2 to 5 test shots are performed using only low-speed injection to raise the temperature of the mold. I do.

In the case of such a low-speed trial shot immediately after the start of operation, the inertial force of the molten metal is weak, so the molten metal does not reach the valve head 7a.
Even if this occurs, the valve 7 will not close, and there is a risk that molten metal may enter the spool 9 side.

Conventionally, in order to avoid such inconveniences, workers put part of the previously cast molded product into vent lines such as gas vent grooves 6 and passages 8 to prevent molten metal from entering the spool side. Alternatively, the valve 7 was closed by manually pushing the above-mentioned return rod 42 or the like.

[Problem to be solved by the present invention] In such a mold gas venting device, the valve 7
When the spool 9 and the spool 9 are set in the mold 1, the spool 9 and the valve 7 are lowered to a predetermined position with the valve 7 open when the mold is clamped.

However, the cylinder 2 that lowers the spool 9
When the valve 7 is started, the pressure of the hydraulic oil is suddenly applied, causing a shock, and a force exceeding the holding capacity of the mechanism that holds the valve open may act, causing the valve 7 to close. In this case, the valve 7 will have already been closed before the injection starts when the valve 7 and spool 9 are set in the mold 1, and this valve device will lose its degassing function, and the gas in the cavity will not be able to escape. Nests form inside the product.

In addition, as shown in the conventional example, when starting operation when the temperature of the mold has decreased due to a long pause, the operator may fill the gas vent grooves 6 and 8 with something, or the return rod 42, etc. When the valve 7 is closed by pushing the molding machine by hand, such manual operation by the operator is extremely troublesome and inconvenient, and furthermore, the operator enters the molding machine, resulting in an extremely dangerous situation.

The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional art, and utilizes a vacuum generator and a compressed air source for cleaning to maintain the valve open state when the spool is lowered during normal operation and to maintain the molten metal state. The valve can be closed reliably by the inertial force of the mold, or the valve can be forcibly closed in advance at the start of operation when the mold temperature is low.
Another object of the present invention is to provide a mold degassing device configured to be able to be operated reliably and easily remotely.

[Means for Solving the Problems] In the present invention, in the gas venting part of the mold, a spool with a slidably provided valve therein is provided so as to be movable in the sliding direction of the valve by means of a cylinder. A locking device that can be installed in the mold and that can lock the valve in the valve open position is provided between the spool and the valve portion, and the rear end of the valve stem portion of the valve is used as a piston to freely slide within the spool. A force generating device is provided to apply a force in the valve closing direction to the valve, and a compressed air source and a second electromagnetic switching valve are connected to the chamber on the front side of the piston via the first electromagnetic switching valve. The valve chamber in the spool is configured to communicate with the compressed air source via the third electromagnetic switching valve, and with the vacuum generator via the fourth electromagnetic switching valve. did.

[Function] When setting the valve or spool in the gas venting part of the mold, open the valve by the action of the locking device, and then
Operate the cylinder to move the valve and spool forward and set them. At that time, the chamber on the front side of the piston at the rear end of the valve stem is communicated with the vacuum generator via the second electromagnetic switching valve to maintain a vacuum state, thereby applying a force to the piston and the valve in the valve opening direction. Let it work. Therefore, even if there is some shock when setting the valve, the valve will not close.

Once the piston is set in the mold with the valve open, the second electromagnetic switching valve is switched to stop the vacuum suction in the chamber on the front side of the piston, and the injection operation begins. During injection, the fourth electromagnetic switching valve is switched to communicate the vacuum generator with the inside of the cavity to vacuum the inside of the cavity and exhaust the gas inside the cavity as much as possible. Further, as the molten metal advances, the remaining gas in the cavity is discharged to the outside of the mold via the open valve portion.

After the molten metal fills the cavity due to the injection operation, if the molten metal moves forward through the gas vent groove and collides with the lower surface of the valve head of the valve, the inertial force of the molten metal is greater than the force of the locking device of the valve. Since it acts on the valve in the state,
The valve is closed and no molten metal enters the valve device. After the valve is closed, the fourth electromagnetic switching valve is switched.

When the injection operation is finished and the molten metal in the cavity and gas vent groove is cooled and solidified, the cylinder is operated to remove the tip of the valve device from the mold.
The mold is opened and then the injection product is taken out.

After removing the tip of the valve device from the mold and opening the valve again, switch the third electromagnetic switching valve to blow compressed air into the valve chamber in the spool to clean the valve seat and valve head. .

The above explanation is for the normal case of continuous molding operation, but when restarting operation after a long period of suspension and the temperature of the mold has decreased, Before starting injection, the first electromagnetic switching valve is switched to supply compressed air to the chamber on the front side of the piston to forcibly close the valve in advance. Of course, if the temperature of the mold rises to a predetermined temperature after several injection operations, this operation is canceled.

[Example] Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

Figures 1 to 3 illustrate one embodiment of the present invention. In the figures, the reference numeral 1 is a fixed mold, 2 is a movable mold, and 1a and 2a are a fixed mold and a movable mold. It is a half-shaped seat fitted into each split surface. Here, the seats 1a and 2a are part of a fixed mold 1 and a movable mold 2, respectively. A degassing device 3 is provided at the dividing plane between the fixed mold 1 and the movable mold 2 and at an extended position thereof.

On the other hand, an exhaust passage is formed from the periphery of the cavity 4 to the lower part of the gas venting device 3 via a gas venting groove 6 from a gas venting path 5 formed on the dividing surface of the mold.

In the gas venting device 3, the valve 7 is provided so that the lower surface of the valve head 7a is substantially perpendicular to the gas venting groove 6, and a detour is made in the lateral direction of the valve head 7a from the middle of the gas venting groove 6. A gas exhaust passage 8 is provided, which is a bypass and extends to the upper side of the valve head 7a. 8a is a hot water pool part.

The valve 7 slides in the axial direction of the spool 9 within the spool 9, which is a valve support member, and when the valve 7 moves upward in FIG. The valve head 7a is in contact with the seat 10, and the passage 8 is connected to the valve chamber 11 in the spool 9.
The communication state with is blocked.

A valve chamber 11 formed around the valve stem 7b is continuous above the valve head 7a, and a discharge port 12 is formed in the valve chamber 11.

A piston 13 that also serves as a spring receiver is fixed to the upper end of the valve stem 7b in the middle of the spool 9.
This piston 13 is slidably fitted in a chamber 14 formed at the upper end of the spool 9, and the piston 13 and the guide member 9b for the valve rod 7b provided on the lower surface of the chamber 14, that is, in the middle of the spool 9, are connected to each other. A compression spring 15 is mounted between the upper surface and the valve 7, and a force is always applied to the valve 7 in the direction of closing it. The compression spring 15 can be said to be a force generating device that applies a force in the valve closing direction to the valve 7, and if this force generating device applies a force in the valve closing direction to the valve 7, It may be configured with parts or structures other than the compression spring 15.

A through hole 9a is formed in the guide member 9b located in the middle of the spool 9 in a state perpendicular to the valve stem 7b, and a steel ball 17 is inserted into the through hole 9a while being pressed by a compression spring 16. This steel ball 17 is in contact with a small diameter portion 7c formed in the middle of the valve stem 7b. Further, the pressing force of the compression spring 16 can be adjusted by a push screw 18. The compression spring 16 and the steel ball 17 constitute a locking device that can lock the valve 7 in an open state.

The steel ball 17 stops the valve 7 which is about to be moved upward by the compression spring 15, and the pressing force of the compression spring 16 is large enough to overcome the elastic force of the compression spring 15. .

Projections 9c, 9c are provided on both sides of the upper end of the spool 9, forming a T-shape.
9a so as to be slidable. This block 19 is connected via a block 19c integrated with it.
It is fixed to the lower end of a piston rod 21a of a cylinder 21 fixed to a bracket 20 fixed to the fixed mold 1 side. 19b is block 19,1
This is the connecting bolt 9c.

On the other hand, as shown in FIG. 1, a groove 19b is formed across the upper end of the block 19, and a lever 22 is fitted into this groove 19b so as to be able to move up and down. The length of the lever 22 may be equal to the width of the block 19 when viewed from the front;
Make the length so that it protrudes beyond the end face of the.

The lever 22 is fixed to the upper end of a pin 23 that is fitted into the center of the block 19 so as to be able to move up and down.
The lower end of the pin 23 faces into the upper chamber of the chamber 14, and faces the piston 13 fixed to the upper end of the valve rod 7b.

A rotary lever 25 is rotatably supported on the front surface of the block 19 via a thumbscrew 24, and when the rotary lever 25 is in the vertical position, its lower end touches the front surface of the upper end on the spool 9 side. ing. As a result, when the rotating lever 25 is in the vertical position, the spool 9 cannot escape from the T-slot 19a, and when the rotating lever 25 is in the horizontal position,
With the spool 9 and the valve 7 moved above the molds 1 and 2, the spool 9 can be pulled out in the horizontal direction.

Further, a compression spring 26 is elastically loaded between both ends of the lever 22 and the block 19.
2 is always pushed upward to prevent the pin 23 and the piston 13 from coming into contact with each other when the lever 22 is raised.

On the other hand, the lever 2 is located in the middle of the bracket 20.
A pair of left and right stoppers 27, 27 are provided in protruding positions at positions where they can come into contact with the stoppers 27, 27.

Further, the block 19c has a protrusion 19f in a part thereof, and this protrusion 19f is attached to the bracket 2.
It is slidably fitted into a guide rod 28 provided on the zero side, and guides the spool 9 when it is raised or lowered, as will be described later.

The block 19 to which the upper end of the spool 9 is connected has a backing plate 2 on the side opposite to the rotating lever 25.
9 is fixed at its upper end with a bolt 30. The lower end of the backing plate 29 extends toward the spool 9, and a proximity sensor 31 is attached to the backing plate 29 at the connecting portion between the block 19 and the spool 9. Proximity sensor 31 detects the position of piston 13 and therefore valve 7 . Then, it is possible to detect whether the valve 7 is in a closed state or an open state, and the detection signal is guided to the control device side via the wiring of the proximity switch 31.

A compressed air source 34 is also provided at the lower end of the backing plate 29.
A connecting hole 29a for connecting to the vacuum generator 35 is formed, and this connecting hole 29a communicates with a through hole 14a that is continuous with the chamber 14 formed at the upper end of the spool 9. And the through hole 14a
An O-ring 32 is attached to the edge of the connecting hole 29a at a position in contact with the edge of the connecting hole 29a, so that the connecting portion between the two can be kept airtight.

Note that the upper chamber of the piston 13 is the spool 9.
It is connected to the outside air through a passage 19e between the block 19 and a passage 25a provided in the rotary lever 25.

A patch plate 29 as described above is provided, and the connection hole 29 is
An O-ring 3 is attached to the contact part of the spool 9 to a.
2, when cleaning the degassing device, the spool 9 can be pulled out from the T-slot 19a and only the spool 9 and the valve 7 can be easily removed. Therefore, the backing plate 29 remains as it is, and the proximity sensor 31 and its wiring and compressed air source 34
The side piping remains as it is on the block 19 side, and there is no need to attach or detach wiring or piping, making cleaning and maintenance operations extremely easy. Of course, when attaching spool 9 to block 19, attach spool 9 to T.
It can be installed extremely easily by simply pushing it into the groove 19a, pressing it against the backing plate 29, and locking it with the rotating lever 25.

One end of a pipe 33 is connected to a through hole 29a communicating with the chamber 14 on the front side of the piston 13, and this pipe 33 is connected to a compressed air source 34 and a vacuum generator 35.

Further, one end of a pipe 36 is connected to a part of the valve chamber 11, and this pipe 36 is also connected to a compressed air source 3.
4 and a vacuum generator 35.

A first electromagnetic switching valve 37 is connected between the pipe 33 and the compressed air source 34, and a second electromagnetic switching valve 38 is connected between the pipe 33 and the vacuum generator 35.

Moreover, between the piping 36 and the compressed air source 34,
The third electromagnetic switching valve 39 also
A fourth electromagnetic switching valve 40 is connected between the two.

Here, in the chamber 14 on the front side of the piston 13, a first
The reason why the compressed air source 34 is connected to the electromagnetic switching valve 37 is that when restarting operation of the molding equipment which has been inactive for a long time and the temperature of the mold is low, the molten metal closes the valve. To prevent part of the molten metal from entering the valve device by forcibly closing the valve by supplying compressed air before starting injection when the valve does not have the necessary inertia to It's for a reason.

Furthermore, a vacuum generator 35 is connected to the chamber 14 on the front side of the piston 13 via a second electromagnetic switching valve 38 to operate the cylinder 21 to open the valve 7 and the spool 9. This is to prevent the valve 7 from closing due to the shock when setting it in the molds 1 and 2, and to apply a force in the valve opening direction to the valve 7 by vacuum suction.

Furthermore, the reason why the compressed air source 34 is connected to the valve chamber 11 in the spool 9 via the third electromagnetic switching valve 39 is to enable the valve 7 to be cleaned by air blowing. The reason why the vacuum generator 35 can be connected to the chamber 11 via the fourth electromagnetic switching valve 40 is to enable the gas in the cavity 4 to be exhausted as much as possible by vacuum suction during injection.

Next, the operation of this embodiment configured as above will be explained.

For example, if the molding equipment has been out of operation for several days or hours and the mold temperature has not reached the specified temperature, the molten metal cannot be expected to have the inertia necessary to close the valve, and then resume operation. When the degassing device 3 is set in the molds 1 and 2, only the first electromagnetic switching valve 37 is switched manually or automatically, the compressed air source 34 and the chamber 14 are communicated, and the compressed air is released. supply and apply air pressure to the piston 13,
The valve 7 can be moved upward against the pressing force of the steel ball 17 to forcibly close it.

By employing a structure in which the operation of closing the valve 7 using air pressure can be performed by remote control, inconvenience and danger to workers can be significantly reduced.

After performing several shots of warm-up operation as described above, the electromagnetic switching valve 37 is turned off, and then an injection operation using a combination of normal low-speed injection and high-speed injection is performed.

In this case, first, only the second electromagnetic switching valve 38 is turned on, the vacuum generator 35 and the chamber 14 are communicated with each other, and the inside of the chamber 14 is vacuumed. By doing so, a downward force acts on the piston 13 and the valve 7, so the action of the cylinder 21 causes the spool 9 to
When lowering the valve, etc., the valve 7 will no longer be closed by the shock.

In this state, the cylinder 21 is operated to lower the spool 9 to a predetermined position and clamp the mold. At this time, the valve 7 is open, so from the cavity 4 to the gas vent path 5, the gas vent groove 6, the passage 8, and the valve chamber 1.
A passageway is formed that passes through the spool 1 and reaches the outside of the spool 9.

In this state, the second electromagnetic switching valve 38 is turned off, only the fourth electromagnetic switching valve 40 is turned on, and the inside of the cavity 4 and the valve chamber 11 is controlled before or during the operation of the injection plunger (not shown). The injection molding operation is performed while vacuum suctioning the gas. In this way, the gas in the cavity 4 is forcibly discharged.

During injection, the molten metal filling the cavity 4 advances through the gas vent path 5 and the gas vent groove 6, but the residual gas in the cavity 4 passes through the passage 8 and the valve chamber 11 and flows toward the discharge port 12. heading to Note that since the gas has a small mass, the valve 7 will not close due to the action of the gas.

On the other hand, following the gas, the molten metal collides with the lower surface of the valve head 7a. At this time, the impact applied to the valve 7 is much larger than the impact applied to the valve 7 by the gas, as the mass of the molten metal is extremely large compared to the gas, and the inertia is large, causing the valve 7 to be thrown upward. As a result, the restraining force of the steel ball 17 pressed by the compression spring 16 is released, the valve 7 faces upward, and the upward pulling force of the compression spring 15 is also applied, so that the upper surface of the valve head 7a Sitting on seat 10,
The space between the passage 8 and the valve chamber 11 is closed, and the outflow of molten metal is stopped at the position of the valve 7.

At this time, even if the molten metal mixes with the gas in the gas vent path 5 and the gas vent groove 6, becomes a droplet, and hits the valve body discontinuously, the valve 7 is splashed by the first collision of the molten metal. Even if the upward pressure from the molten metal disappears when the gas comes, the valve 7 has a tendency to move upward due to the force of the compression spring 15, so the exhaust passage is not blocked by the valve 7. will definitely be done.

Further, as is clear from FIG. 1, the valve head 7a
has an extremely deep recess 7b formed on its lower surface, so most of the molten metal, metal powder, etc. collide into this recess 7b, and the molten metal passes around the valve head 7a and enters the valve head 7a. The inconvenience of turning upward is eliminated, and the valve head 7a can be reliably seated on the valve seat 10.

Note that even when the valve 7 moves upward and the valve head 7a is seated on the valve seat 10, a predetermined space is provided between the piston 13 at the upper end of the valve 7 and the lower surface of the pin 23. Therefore, the problem of the pin 23 coming into contact with the piston 13 and pushing the valve 7 downward does not occur.

Injection is performed in this way, and the gas venting device 3
When the casting operation is completed by pressurized cooling for a predetermined period of time with the valve 7 closed, the cylinder 21 is activated and the spool 9 is raised. As the valve moves upward, the solidified metal filling the cavity 4, the gas vent path 5, the gas vent groove 6, and the passage 8 separates from the valve 7 during the upward movement. After that, after opening the mold, the product is extruded using a product extrusion device (not shown).
Remove the molded product from the movable mold.

When the cylinder 21 is actuated and the entire spool 9 is pulled up, both ends of the lever 22 attached to the block 19 come into contact with a stopper 27 protruding from the bracket 20 side. and compression spring 26
The lever 22 moves down in the groove 19b against the elastic force of Overcome and push downward.

As a result, the valve head 7a separates from the valve seat 10 and the valve is fully opened.

As the valve 7 descends, the steel ball 17 again fits into the small portion 7c formed in the middle of the valve stem 7b, keeping the valve 7 open. In this state, the next casting operation may be performed in the same manner as described above.

When cleaning the area around the valve 7 and the valve seat 10 that are open above the molds 1 and 2, only the third electromagnetic switching valve 39 is turned on and compressed air is guided to the valve chamber 11 side. At this time, since the valve 7 is in an open state, the inside of the valve chamber 11 and the vicinity of the valve head 7a and the valve seat 10 are cleaned by the compressed air, and metal powder and the like are removed. Therefore, the valve 7 can be completely closed the next time the valve is closed.

In this way, the valve can be opened/closed or maintained in the open/closed state using the conventionally used compressed air source 34 for cleaning and the vacuum source generator 35 for degassing by vacuum suction.

In addition, in this embodiment, the valve 7 and the lever 22
It is provided separately from the valve 7, and when the valve is closed, only the valve 7 can be operated. Therefore, compared to the conventional valve 7 that is integrated with the lever 22, the mass is smaller, the inertia during operation is smaller, and the closing speed of the valve when the molten metal collides with the valve body is extremely fast and excellent. It has excellent responsiveness.

Note that when the valve 7 is set as shown in FIG. Valve head 7
It is set to be somewhat larger than the distance between the upper outer circumferential surface of a and the valve seat 10.

On the other hand, if the position of the stopper 27 is selected, it can be set so that the stopper 27 and the lever 22 are in contact with each other and the valve 7 can be lowered by more than the above stroke when the spool 9 is pulled up to the maximum extent.

When such a structure is adopted, a large distance can be provided between the valve head 7a and the valve seat 10, a large space can be secured when cleaning the valve, and metal powder and the like can be reliably removed.

In the above embodiment, a compressed air source 34 and a vacuum generator 35 are connected to the chamber 14 on the front side of the piston 13 and the valve chamber 11 in the spool 9 through four two-way electromagnetic switching valves 37 to 40, respectively. The number of electromagnetic switching valves can be reduced by using, for example, a four-way electromagnetic switching valve.

[Effects of the Invention] As described above, according to the present invention, a spool with a slidably provided valve inside the mold is provided in the gas venting part of the mold so as to be movable in the sliding direction of the valve by means of a cylinder. A locking device that can be installed on the mold and that can lock the valve in the valve open position is provided between the spool and the valve portion, and the rear end of the valve stem portion of the valve is used as a piston to slide into the spool. A second electromagnetic switching valve is provided with a force generating device that can be freely installed and applies a force in the valve closing direction to the valve, and a vacuum generating device that can be activated when the spool is installed in the mold is installed in a chamber on the front side of the piston. Since a structure in which the valves are connected via a valve is adopted, the valve can be opened and closed or opened and closed in a sufficient manner. In other words, by evacuating the chamber on the front side of the piston when installing the spool in the mold, a force in the valve opening direction can be applied to the piston and valve stem, so that the valve opening due to the shock when the spool is lowered can be applied to the piston and valve stem. Valve opening operation can be sufficiently prevented. Further, in conjunction with the action of the locking device that can lock the valve in the open state, the valve can be sufficiently maintained in the open state.

Of course, when the spool is installed in the mold, the valve is definitely open, so when the vacuum is stopped from the front chamber of the piston and injection is performed, the present invention ensures that the gas is sufficiently In addition to being able to perform a drawing action, the valve closes quickly, reliably, easily, and automatically at extremely good timing due to the inertial force of the injected molten metal.

In addition, in the present invention, a force generating device is provided that applies a force in the valve closing direction to the valve, such as a compression spring provided in the chamber on the front side of the piston, so that the valve that is once closed during injection is activated during injection. You can prevent it from opening. In addition, since a compressed air source is connected to the chamber on the front side of the piston via the first electromagnetic switching valve, the valve can be activated by applying operating pressure to the chamber on the front side of the piston by remote or automatic operation. Can be forcibly closed. Therefore, after the molding equipment has been stopped for a long period of time, the temperature of the mold has dropped and the inertia of the molten metal cannot be obtained sufficiently, so it is necessary to close the valve in advance during the first few shots when restarting operation. By doing so, it is possible to prevent inconveniences such as molten metal from flowing around to the valve chamber side. As a result, after a few shots have passed after the start of operation, the temperature of the mold reaches a predetermined temperature, the molten metal flows smoothly, and a predetermined inertia force is obtained. It is possible to smoothly shift to continuous molding operation in which the valve device operates normally.

Further, in the present invention, when the spool and valve are installed in the mold with the valve open, the chamber on the front side of the piston can be communicated with to generate a vacuum state, and the fourth electromagnetic switching valve can be switched at the time of injection. As a result, a vacuum generator was provided that communicated with the spool and could create a vacuum inside the cavity through the valve part in the open state. During installation, as mentioned above, the chamber on the front side of the piston must be kept in a vacuum state to prevent the valve from closing, and during injection after installation of the spool or valve into the mold, the inside of the cavity must be evacuated through the inside of the spool. both of creating a vacuum,
It can be easily switched. Therefore,
One vacuum generator can be used effectively, and
The reliable operation of the valve and the generation of a vacuum state inside the cavity during injection, as well as the closing action of the valve due to the inertial force of the molten metal during injection, ensure that the gas in the cavity is discharged and the valve is closed during injection. The closing operation can be performed reliably and easily, and a molded product without cavities can be reliably and easily obtained.

Further, in the present invention, when the spool in the valve closed state and the valve are removed from the mold, a compressed air source is provided that can switch the third electromagnetic switching valve to communicate with the inside of the spool. It is possible to reliably and easily remove powder of metal coagulation adhering to the valve by air blowing.

In addition, both a vacuum generator and a compressed air source are provided, and these can be selected and used as appropriate to communicate with the chamber inside the spool or the front side of the piston, so the vacuum inside the spool or the chamber on the front side of the piston can be Piping and air supply piping can be used in common. In that case, even if powder of metal coagulation should get into the pipe during vacuum suction, it can be removed by blowing it out to the outside with compressed air during the next air blow.

In addition, in the present invention, as conventionally known, the gas discharge port provided on the spool can be opened to the atmosphere or connected to a vacuum suction device, and the flow of molten metal can be controlled. It is possible to close the valve using an electrical command during normal injection, but in that case, if the timing of the electrical command is not well-timed, the molten metal may reach the valve part before the command closes the valve. The molten metal enters the valve device and the operation of the valve device becomes uncertain, but even in that case, the inertial force of the molten metal closes before the valve closes due to a late electrical command during injection. Since the valve closes, the valve closing operation is always performed reliably, is safe, and can sufficiently withstand long-term continuous operation.

Furthermore, in the present invention, the valve device has relatively few moving parts and is light, so it is relatively compact, the valve closes quickly, and the response is good.

[Brief explanation of drawings]

1 to 3 show one embodiment of the present invention,
FIG. 1 is a longitudinal sectional view, FIG. 2 is a partially sectional front view, FIG. 3 is a sectional view taken along the - line in FIG. 1, and FIG. 4 is a longitudinal sectional view showing an example of a conventional device similar to the present invention. It is a front view. DESCRIPTION OF SYMBOLS 1... Fixed mold, 2... Movable mold, 3... Gas venting device, 4... Cavity, 7... Valve, 7a...
... Valve head, 7b... Valve stem, 7c... Small diameter part, 8...
...Passage, 9...Spool, 10...Valve seat, 11...
...Valve chamber, 13...Piston, 14...Chamber, 15,
16, 26...Compression spring, 17...Steel ball, 19...Block, 19a...T groove, 21...
... Cylinder, 22 ... Lever, 25 ... Rotating lever, 27 ... Stopper, 34 ... Compressed air source, 3
5... Vacuum generator, 37-40... Solenoid switching valve.

Claims (1)

[Claims] 1 In the gas venting part of the molds 1 and 2, the spool 9 with the valve 7 slidably provided inside is inserted into the cylinder 21.
A locking device 16, 17 is provided between the spool 9 and the valve 7 part so as to be movable in the sliding direction of the valve and installed in the molds 1 and 2, and capable of locking the valve 7 in the valve open position. A force generating device 15 is provided, the rear end of the valve stem 7b of the valve 7 is used as a piston 13, and is slidably provided in the spool 9, and applies a force in the valve closing direction to the valve 7, and Chamber 1 on the front side of the piston 13
4 and the electromagnetic switching valve 37 to the valve chamber 11 in the spool 9.
A gas venting device for a mold is structured so that a compressed air source 34 and a vacuum generator 35 can communicate with each other via 40.