JPH0230778B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling a mold degassing device equipped with a valve body capable of responding at high speed and used in a molding machine such as a die-casting machine.

Conventionally, die casting has been widely used as a method for manufacturing precision products in large quantities, but there are cases where die casting is not suitable for products where the integrity of the product without porosity is important.

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 sufficiently released and may remain as cavities in the product mixed with the molten metal.

In order to eliminate these inconveniences, the applicant's company has developed a method that allows a large amount of gas to be reliably and easily removed, and to eliminate gas entrainment and obtain sound die-cast products despite the limitations of cast products and molds. We have developed a gas venting device for molds that allows this.

This device performs injection with the discharge path leading from the mold cavity to the outside of the mold opened by the action of a valve, and when the gas with a small mass in the cavity has been exhausted through the gas discharge path, By applying the inertial force of the large mass of the molten material to be injected that has advanced from inside the cavity directly to the valve, the valve is reliably and quickly moved and closed, directly cutting off the gas discharge path and removing this gas. It is possible to prevent the melt to be injected from flowing out from the discharge path, and to ensure that gas in the mold can be vented easily during injection.

This kind of degassing device for molds works smoothly when the molding machine is in continuous operation, but when the molding machine starts operating, the mold and other parts are cooled down and the flow of the molten metal is affected. In bad cases, it would not work reliably.

That is, when the molding machine starts operating, the mold and other parts are cooled, and if normal injection operation is performed in this cooled state, the molten metal will cool down before it reaches every corner of the mold cavity. A part of the product may not be molded.

During injection molding, low-speed injection is performed at the initial stage of injection, followed by high-speed injection, but at the beginning of molding, 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 run immediately after the start of operation, the flow of the molten metal is poor and the inertia is weak, so even if the molten metal hits the valve head, the valve will not close, and the valve will reliably shut off the gas exhaust path. Otherwise, the molten metal may flow out of the gas discharge passage and enter the spool side. Once the molten metal enters the spool side, the molten metal solidifies and the mold degassing device itself will no longer work the next time, so it is necessary to disassemble, maintain, assemble, and install it.

Conventionally, in order to avoid such inconveniences, workers put part of the previously cast molded product into vent lines such as gas vent grooves and passages to prevent molten metal from entering the spool side. Alternatively, the valve was closed by manually pushing a lever or the like connected to the valve.

Such manual operation by an operator is extremely troublesome and inconvenient, and furthermore, it is extremely dangerous because the operator enters the molding machine side.

In addition, even during normal continuous operation when the mold etc. reaches a predetermined temperature, the temperature of the molten metal is too low than the predetermined temperature and the injected molten metal does not generate the predetermined inertia force. It has the same drawbacks and dangers.

The present invention aims to eliminate these drawbacks, and includes a spool with a slidably installed valve inside that can close the valve when the inertia of the molten metal acts on it.
It can be installed and removed from the gas exhaust path leading from the cavity to the outside of the mold, and is movable in the sliding direction of the valve using a cylinder.The rear end of the valve stem has a piston structure and slides into the spool. Set up freely,
The valve can also be closed by applying fluid pressure to the piston, and a lever that is separate from the valve and has a valve abutment part can be moved into the spool so that the valve can slide freely. For molds, a member is provided between the lever and the spool to constantly apply a force in the backward direction to the lever, and a stopper is provided outside the spool to stop the lever from retracting and open the valve while the spool is retracting. Using a degassing device, we set the minimum value of the injection temperature condition for the valve closing operation due to the inertia of the molten metal, measured the actual injection temperature condition, and determined whether the measured value of the injection temperature condition was the one for the valve closing operation. When the temperature is below the set value of the minimum injection temperature condition, fluid pressure is applied to the piston to automatically close the valve.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

1 and 2 illustrate one embodiment of the apparatus used for carrying out the present invention, in which the reference numeral 1 denotes a fixed mold, 2 a movable mold, 1a,
Reference numeral 2a designates half-split seats fitted into the dividing surfaces of the fixed mold and the movable mold. Here, locus 1a,
2a are a part of a fixed mold 1 and a part of a movable mold 2, respectively. A degassing device 3 is provided at the dividing plane between the fixed mold 1, the movable 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.

As 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 the valve head 7a is inserted from the middle of the gas venting groove 6.
A discharge passage 8 is provided which is a bypass that detours in the lateral direction of the valve head 7a and reaches 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. Valve head 7 on seat 10
a contact, and communication between the passage 8 and the valve chamber 11 in the spool 9 is closed.

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 spring receiver 13 is fixed to the upper end of the valve stem 7b in the middle of the spool 9.
is slidably fitted in a chamber 14 formed at the upper end of the spool 9 like a piston, and a guide member 9b for the valve rod 7b provided on the lower surface of the spring receiver 13 and the chamber 14, that is, in the middle of the spool 9. A compression spring 15 is mounted between the upper surface of the valve 7 and the valve 7, and a force is applied to the valve 7 in the direction of closing it at all times.

A through hole 9a is formed in the guide member 9b 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 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 support frame 20 fixed to the fixed mold 1 side. 19d is block 19, 19c
This is a bolt for connection.

A spool 9 that is slidably provided with a valve 7 that can close the valve when the inertia of the molten metal acts on it.
is attached to and detachable from the gas vent groove 6 of the molds 1 and 2, and is movable in the sliding direction of the valve 7 by means of a cylinder 21.

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 spring receiver 13 fixed to the upper end of the valve rod 7b. The lower end surface of the pin 23 also serves as a valve abutment portion to be described later.

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 groove 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 from coming into contact with the spring receiver 13 when the lever 22 is raised.

On the other hand, a pair of left and right stoppers 27, 27 are provided in the middle of the support frame 20 so as to project to a position where they can come into contact with the lever 22.

Further, the block 19c has a protrusion 19f in a part thereof, and this protrusion 19f is slidably fitted into a guide rod 28 provided on the support frame 20 side, so that the spool 9 can be inserted into the guide rod 28 as described later. Provide guidance when going up and down.

In this embodiment configured as described above, the following operations are performed.

First, with the mold open and the small diameter portion 7 of the valve stem 7b
Press the steel ball 17 against the lower end step of c.
With the valve head 7a separated from the valve seat 10, that is, with the valve open, the entire spool 9 is lowered by operating the cylinder 21.

When the fixed mold 1 and the movable mold 2 are clamped in this state, a passage is formed from the cavity 4 to the outside of the spool 9 via the degassing path 5, degassing groove 6, passage 8, and valve chamber 11. .

Then, in this state, an injection plunger (not shown) operates to supply molten metal into the cavity 4. At this time, the molten metal filling the cavity 4 advances through the gas vent passage 5 and the gas vent groove 6, but the gas inside the cavity 4 passes through the passage 8 and the valve chamber 1.
1 and head toward the discharge port 12. 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 is seated on the valve seat 10. Aisle 8
and the valve chamber 11 to prevent the outflow of molten metal from the valve 7.
Stop at the position.

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 first collision of the molten metal causes the valve body to be blown away. Even if the upward pressure from the molten metal disappears when the gas comes, the valve 7 is given the habit of moving upward by the force of the compression spring 15, so the valve 7 will not block the exhaust passage. It will definitely be done.

Furthermore, as is clear from FIG. 1, since the valve head 7a has an extremely deep recess 7d formed on its lower surface, most of the molten metal and metal powder collide into this recess 7d. The inconvenience that the valve head 7a passes around the valve head 7a and above the valve head 7 is eliminated, and the valve head 7a can be reliably seated on the valve seat 10.

Note that the valve 7 moves upward, and the valve head 7a touches the valve seat 1.
Even in the state where the valve 7 is seated in the position 0, since there is a predetermined space between the spring receiver 13 at the upper end of the valve 7 and the lower surface of the pin 23, the pin 23 contacts the spring receiver 13, and the valve 7 There is no inconvenience caused by pushing downward.

Injection is carried out in this manner, and when the casting operation is completed by pressurized cooling for a predetermined period of time with the valve 7 of the degassing device closed, the mold is opened, the cylinder 21 is operated, and the spool 9 to rise. With this upward movement, the solidified metal filling the cavity 4, gas vent path 5, gas vent groove 6, and passage 8 separates from the valve 7, and the molded product is moved by a product extrusion device (not shown). Remove from mold.

When the cylinder 21 is actuated and the entire spool is pulled up, both ends of the lever 22 attached to the block 19 come into contact with stoppers 27 protruding from the support frame 20 side. Then, the lever 22 moves down in the groove 196 due to the elastic force of the compression spring 26, and as a result, the pin 23 moves down, and the lower end surface of the pin 23, which is the valve abutment part, moves the valve 7 at its upward movement limit. The compression spring 15 contacts the spring receiver 13 at the upper end of the
overcoming the force of and pushing downward.

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

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

In addition, if you wish to clean or maintain the entire degassing device 3, loosen the thumbscrew 24, rotate the rotating lever 25 approximately 90 degrees, and position it from the vertical position to the horizontal position. The protruding portion 9c formed in the portion can be easily removed from the T-slot 19a, and the entire spool 9 can be removed extremely easily.

In the gas venting device according to the present invention that operates as described above, the valve 7 and the lever 22 are provided separately, and when the valve is in the closed state, 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 valve closes at an extremely fast speed when the molten metal collides with the valve body. Be responsive.

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 spring receiver 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 led to the control device side via the wiring 31a.

Further, a connecting hole 29a for connecting to an air source is formed at the lower end of the backing plate 29, 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. are doing. An O-ring 32 is attached to the edge of the through hole 14a at a position in contact with the edge of the connecting hole 29a, so that the connection between the two can be kept airtight.

A patch plate 29 as described above is provided, and the connection hole 29 is
An O-ring 32 is placed in the contact area with the spool 9.
By adopting the structure provided with this, 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 caul plate 29 remains as it is,
The proximity sensor 31, its wiring 31a, and piping on the air source 34 side remain as they are on the block 19 side, and there is no need to attach or detach the wiring or piping, making cleaning and maintenance extremely easy. Of course, when attaching the spool 9 to the block 19, it can be attached extremely easily by simply pushing the spool 9 into the T-groove 19a, pressing it against the backing plate 29, and locking it with the rotating lever 25.

A compressed air source 34, which is a fluid pressure supply source, is connected to the connecting hole 29a via an electromagnetic switching valve 33.
Here, the electromagnetic switching valve 33 and the compressed air source 34 apply fluid pressure to the piston formed by the spring receiver 13 etc. to close the valve 7 when it is inconvenient for the valve 7 to be open at the start of operation of the molding machine. It forms a fluid pressure supply device that acts on the structure. The piston structure including the spring receiver 13 provided at the rear of the valve 7, the fluid pressure supply device, etc. serve as a valve closing actuation member that closes the valve in response to an external command other than the inertia of the molten metal. I can say it.

Note that the upper chamber of the spring receiver 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 temperature detection section 50 is provided in a part of the fixed mold 1 or the movable mold 2, for example, near the cavity or near the gate, to detect the temperature inside the mold and output it as an electric output. 51 is a setting device for setting the minimum value of the temperature of the mold necessary for normal operation of the gas venting device 3; 52 is a setting device for setting the electrical output from the temperature detection section 50 and the setting section 51; In comparison, the electromagnetic switching valve 3 outputs an electric signal only when the temperature of the mold is lower than the temperature set by the setting device 51.
This is a comparator for switching 3. Therefore,
During normal injection when the mold temperature is above a predetermined temperature, the electromagnetic switching valve 33 does not operate, and the valve 7 is closed only by the inertia of the molten metal, so that the mold is When the specified temperature has not been reached,
Or, even during normal injection operation, if the temperature drops below the mold temperature, the solenoid switching valve 33 is automatically switched in response to a command from the comparator 52, and the compressed air source 34 and the chamber 14 are communicated with each other. Air is supplied and air pressure is applied to the spring receiver 13 having a piston structure, and the valve 7 is moved upward against the pressing force of the steel ball 17 to forcibly close the valve 7.

In the embodiment shown in FIG. 1, the valve 7 is forcibly closed when the temperature of the mold is below a predetermined temperature. Even if the temperature of the molten metal in the ladle that is fed into the injection sleeve (not shown) is below a predetermined temperature, the flow of the molten metal in the mold will be poor and the inertia of the molten metal will be small. It can be carried out.

In the above example, the valve closing operation was performed by an external command other than the inertia force of the molten metal only when the temperature of the mold or the molten metal was low. Even when other injection conditions that affect the magnitude of the inertia of the molten metal, such as injection pressure and injection speed, are actually lower than the minimum value of the injection conditions for the valve to close due to the inertia of the molten metal, the external command Therefore, the valve can be closed.
Of course, in that case, a measuring device, a setting device, etc. corresponding to the injection pressure, injection speed, etc. are required.

Furthermore, if the measured value of the actual injection temperature condition such as the mold temperature is less than the set value of the minimum injection temperature condition for valve operation due to the inertia force of the molten metal, a command is given to the valve closing member to close the valve. In addition to automatically closing, a lamp or a buzzer can be used to notify the operator or issue an alarm.

If a method is adopted in which the valve 7 can be automatically closed by an external command other than the inertia force of the molten metal when the inertia force of the molten metal is small, it will significantly reduce the inconvenience and danger to the workers. can be lowered.

In the embodiment described above, a compression spring 15 housed in the chamber 14 is used as a means for applying a force to the valve 7 in the closing direction. However, if the cylinder 21 or the like is used when setting up this degassing device, a shock may occur when starting the device, and if this shock is greater than the restraining force of the steel ball 17 on the valve 7, the valve may be damaged when the spool 9 is lowered. 7 may close.

In order to prevent such a danger, a structure as shown in FIG. 3 may be adopted.

That is, excluding the compression spring 15 housed in the chamber 14, a pressure reducing valve 35, electromagnetic switching valves 36, 37 are installed in the pipe line connecting the compressed air source 34 connected to the connecting hole 29a in order from the compressed air source 34 side. A structure with an intervening structure was adopted.

A bypass pipe line 39 that bypasses the pressure reducing valve 35 is provided between the compressed air source 34 and the electromagnetic switching valve 36, and is connected to the T port of the electromagnetic switching valve 36.

When such a structure is adopted, during normal injection operation, the electromagnetic switching valves 36 and 37 are in the state shown in FIG. Air pressure is chamber 14
guided within. This air pressure corresponds to the elastic force of the compression spring 15 in the embodiment shown in FIGS. 1 and 2, and is normally smaller than the restraining force of the steel ball 17 on the valve 7.

Therefore, during normal injection molding, this air pressure serves as a substitute for the compression spring 15, and the valve 7 can be closed by the inertial force of the molten metal.

When it is desired to forcibly close the valve 7, such as at the start of operation, the solenoid switching valve 36 is automatically switched between the T port and the A port in the same manner as explained in FIG.
When the port is connected, the pressure of the compressed air source 34 is directly introduced into the chamber 14, the spring receiver 13 having a piston structure is pushed upward by the air pressure, and the valve 7 is closed.

Furthermore, when lowering the spool 9 with the valve 7 open, the electromagnetic switching valve 36 remains in the state shown in FIG. 3, and only the electromagnetic switching valve 37 is switched to connect the A port to the EX port. . The pressure in the air source 34 is then blocked and the pressure in the chamber 14 is then blocked.
is open to the atmosphere. Therefore, the valve 7 applies only the restraining force of the steel ball 17, and the cylinder 2
Even if a shock occurs at the time of starting the valve 7, the valve 7 will not close, and its role as a gas venting device can be reliably maintained.

Note that in the fluid pressure supply device, a hydraulic pressure supply source can be used instead of the compressed air source 34.
However, in that case, the electromagnetic switching valves 33 and 37
Connect the EX port to the tank. Instead of applying the pressing force to the steel ball 17 with the compression spring 16, it is also possible to apply it using fluid pressure.

As is clear from the above description, according to the present invention, since the structure described in the claims is adopted, when the temperature of the mold is too low at the start of operation of the molding machine, or during normal operation, If the inertia of the molten metal is small when injected, such as when the temperature of the molten metal is too low, the valve can be automatically closed, so the molten metal will not close and the molten metal will enter the valve chamber. No untoward accidents will occur. In addition, when the valve does not close due to the inertia of the molten metal, the valve can be automatically closed, eliminating the need for manual operation by the operator and reducing complexity and hassle. There is no danger at all.

Further, according to the present invention, the rear end of the valve stem of the valve has a piston structure and is slidably provided in the spool, and the valve closing operation is also performed by applying fluid pressure to the piston. A lever that is separate from the valve and has a valve contact portion is provided within the spool so as to be movable in the sliding direction of the valve, and a force in the backward direction is constantly applied to the lever between this lever and the spool. Since the control is performed using a degassing device for a mold that is provided with a member that keeps the valve closed, the degassing device used in the present invention has a valve and a lever separately provided, and the valve is closed. Sometimes only the valve can be moved.

Therefore, compared to conventional valves in which the lever and valve are integrated, the mass of the parts that move when the valve is closed is small, the inertia during operation is small, and the molten metal does not reach the valve body. On the other hand, when the valve collides with the robot or closes the valve using fluid pressure, the valve closes extremely quickly and has excellent responsiveness.

Therefore, when there is not much time to spare, such as when performing valve closing control based on mold temperature or molten metal temperature, as in the present invention, the responsiveness of this valve closing operation is excellent. is very advantageous in practice.

In addition, in the present invention, since the valve closing control is performed based on the mold temperature and the molten metal temperature, it is possible to detect whether the flow condition of the molten metal is good or not, and thereby make it possible to close the molten metal by a predetermined amount or more necessary to close the valve. It is possible to know whether inertial force is obtained or not, and accordingly,
The method of closing the valve can be appropriately selected and controlled.

Of course, the mold gas venting device used to carry out the present invention normally and quickly closes the valve due to the inertia of the molten metal during normal injection, so the mold gas venting device used to carry out the present invention closes the valve normally and quickly due to the inertia of the molten metal. The gas inside the mold cavity can be reliably and easily vented, making it possible to obtain high-quality injection products with no cavities.
This degassing device can be used continuously and semi-permanently by preventing molten metal from entering the mold degassing device.

[Brief explanation of drawings]

1 and 2 are longitudinal cross-sectional views and partially sectional front views showing one embodiment of the apparatus used to carry out the present invention, and FIG. 3 is another embodiment of the apparatus used to carry out the present invention. FIG. 1... Fixed mold, 2... Movable mold, 3... Gas venting device, 4... Cavity, 7... Valve, 9... Sprue, 1
0...Valve seat, 11...Valve chamber, 13...Spring receiver, 15,
16, 26... Compression spring, 17... Steel ball,
19... Block, 19a... T groove, 21... Cylinder, 22... Lever, 25... Rotating lever, 27... Stopper, 33, 36, 37... Solenoid switching valve, 34...
Compressed air source, 35...pressure reducing valve, 50...temperature detection unit,
51...Setter, 52...Comparator.

Claims (1)

[Claims] 1. A spool with a slidably provided valve inside that can close the valve when the inertia of the molten metal acts on it,
It can be installed and removed from the gas exhaust path leading from the cavity to the outside of the mold, and is movable in the sliding direction of the valve using a cylinder.The rear end of the valve stem has a piston structure and slides into the spool. Set up freely,
The valve can also be closed by applying fluid pressure to this piston, and a lever that is separate from the valve and has a valve contact portion can be moved in the sliding direction of the valve within the spool. For molds, a member is provided between the lever and the spool to constantly apply a force in the backward direction to the lever, and a stopper is provided outside the spool to stop the lever from retracting and open the valve while the spool is retracting. Using a degassing device, we set the minimum value of the injection temperature condition for the valve closing operation due to the inertia of the molten metal, measured the actual injection temperature condition, and determined whether the measured value of the injection temperature condition was the one for the valve closing operation. A method for controlling a gas venting device for a mold, wherein when the temperature is below a set value of a minimum injection temperature condition, fluid pressure is applied to the piston to automatically close a valve.