JPH034429Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a gas venting device for a mold of an injection molding machine such as a die casting machine or an injection molding machine, which extracts a large amount of gas from the cavity of the mold during injection molding. .

Conventionally, when molten metal is injected into the cavity of a mold at high speed and high pressure in a die-casting machine, etc., there has been a drawback that the gas in the cavity cannot be sufficiently released and remains in the product, forming cavities in the product. .

The present invention aims to eliminate this drawback.During injection, the gas vent valve for the mold is opened, and a large amount of gas in the cavity is discharged through the valve. The valve is closed to prevent the molten material to be injected from coming out of the valve.

In the present invention, a degassing valve is provided in the cavity of the mold or in the part of the degassing groove led from the cavity where the molten metal comes, and a solenoid device is installed at the rear end of the valve stem of this valve. A seat-type valve seat is provided on which the valve head of the valve is seated on a member that supports the valve stem so as to be slidable in the axial direction. A spring acting in the direction of opening the valve is provided on the rod, and when the movable mold is in a clamped state in contact with the fixed mold, and the valve head is pressed against a part of the mold by the action of the spring. When the valve is opened, there is a gap between the sleeve and a block provided on a part of the rear end of the valve stem, so that when the valve is opened, the valve can be further opened by the action of the spring. A block is attached to the valve stem, and an operation instruction device using a timer is provided which instructs the solenoid device to operate during the forward movement of the injection cylinder, and the solenoid device is actuated by the electric command generated by the operation of the operation instruction device, and the valve is activated. can now be closed.

Next, the present invention will be explained in more detail with reference to embodiments shown in the drawings.

Fig. 1 shows one embodiment of a die casting machine, in which 1 is a fixed plate, 2 is a fixed mold, 3 is a movable mold, 4 is a cavity, 5 is an injection cylinder, and 6 is a mold.
is an injection plunger integrally attached to the piston rod of the injection cylinder 5 via a coupling 5a;
26 is a forward start command device for the injection cylinder 5;
7 is an electromagnetic switching valve for advancing the injection cylinder 5, and 28 is a timer.

A degassing valve 9 is provided in a portion where the molten metal guided from the cavity 4 provided in the separation surface between the fixed mold 2 and the movable mold 3 comes from the degassing groove 8, so as to be openable and closable.
A solenoid 10 that closes this valve 9 was attached to the fixed platen 1 or the mold.

That is, a sleeve 11 was attached to the fixed mold 2 facing toward the movable mold 3, and the valve stem 9a of the valve 9 was slidably positioned on the central shaft portion of the sleeve 11. 9b is the valve head of the valve 9 which can be positioned in the recess 12 of the fixed mold 3, and 11a is the valve stem 9a.
A seat-type valve seat 13 is provided on a sleeve 11 which is a support member for the air conditioner, and 13 is an exhaust port. A shaft 15 is attached to the rear end of the valve stem 9a via a block 14, and the shaft 15 is moved in the axial direction by the operation of a solenoid 10.

The solenoid 10 and the shaft 15 that moves directly under the action of the solenoid 10 form a solenoid device, in which the valve stem 9a of the valve 9 and the shaft 15 of the solenoid device
are arranged on the same axis and are integral with each other.

A relatively weak compression spring 17 is provided in the hole 16 between the block 14 and the stationary platen 1. In the state shown in FIG. 1, there is a slight gap between the rear surface of the sleeve 11 and the front surface of the block 14.
When the mold was opened, valve 9 was also slightly opened to make it easier to clean the valve part with air blow.

When the solenoid 10 is energized, the shaft 15 moves to the right in the figure, and the valve 9 closes, and when the solenoid 10 is deenergized, the shaft 15 and block 14 move to the left in the figure by the action of the compression spring 17, and the valve 9 opens. .

In order to operate the solenoid 10, an operation instruction device using a preset timer was used. As an operation instruction device using a timer, for example, as shown in FIGS. 1 and 3, the injection cylinder 5
The forward start command signal issued from the forward start command device 26 switches the electromagnetic switching valve 27 for advancing the injection cylinder 5 to start moving the injection plunger 6 of the injection cylinder 5 forward. The timer 28, which is set to an appropriate time depending on the shape of the injection product and the injection conditions, starts to measure time, and when the timer 28 times out, the solenoid 10 device for operating the valve 9 is activated while the injection plunger 6 is moving forward. A device was used that could electrically give operating instructions to the robot.

The timer-based operation instruction device is electrically connected to the solenoid 10 via a relay 19, and the solenoid 1 is activated by the electrical instruction from the operation of the operation instruction device.
0 device was activated so that valve 9 could be opened and closed.

The reason why the solenoid 10 device that directly operates the valve 9 is used to close the gas discharge valve 9 while the injection plunger 6 is moving forward is because the operating stroke of the solenoid 10 device is extremely short, for example, 5 mm or less. The opening/closing stroke of the can be made extremely short.
This is because the time required for the closing operation of the valve 9 can be extremely reduced, and the responsiveness is extremely good and the operation is quick. In order to close the valve 9 by a certain amount of anticipatory operation during injection, it is necessary to adopt a driving method that satisfies these conditions, and a solenoid is most suitable for this purpose. That is, if the valve 9 is closed by other methods, such as a pneumatic or hydraulic cylinder, the injection plunger 6 is normally used.
It is conceivable to operate the limit switch during the forward movement of the cylinder, which in turn activates the electromagnetic switching valve to operate the cylinder. There is a delay in the time required for the piston rod to start moving forward after the pressure oil enters the piston rod.
It takes a relatively long time for the limit switch to operate and for the valve 9 to close. The shorter the time it takes for the limit switch to operate and the valve 9 to close, the better. For example, it is desirable to set it to about 5 msec, but if a solenoid 10 device is used as in the present invention, it will take 5 msec.
sec, but if you use a method of closing valve 9 using an electromagnetic switching valve and a cylinder, it will take more than three times this time, and the high-speed injection will occur in an extremely short period of 0.1 to 0.2 seconds. Therefore, it becomes difficult to adjust the time for a very delicate expected operation start command. Therefore, in the present invention, the valve 9
For the closing operation, a solenoid 10 device was used that allows the valve stem 9a of the valve 9 to be moved immediately.

Now, in the state shown in FIG. 1, if the molten metal is supplied into the injection sleeve (not shown) and the injection cylinder 5 is operated to move the injection plunger 6 forward, the molten metal will enter the cavity 4. A large amount of gas in the cavity 4 is discharged from the exhaust port 13 through the open valve 9. If the preset timer 28 times out at or just before the gas in the cavity 4 escapes and the cavity 4 is filled with molten metal, the solenoid 1
0 is energized, the shaft 15 is pulled, and the valve 9 is closed. This acts to prevent the molten metal from coming out of the valve 9. At this time, gas remains in the recess 12 and part of the gas vent groove 8, but this does not have any adverse effect on the injection product. When the injection is completed, the mold is opened and the product is extruded, and the injection cylinder 5 is moved back.

At this time, the solenoid 10 is demagnetized. The valve 9 then opens further under the action of the spring 17 until the block 14 comes into contact with the rear end surface of the sleeve 11. In this state, compressed air is sent in reverse from the exhaust port 13 to clean the inside of the valve 9 and the seating surfaces of the valve head 9b and valve seat 11a by air blowing. This is to avoid the possibility that if powder of solidified molten metal gets into the valve 9, the operation of the valve 9 may become uncertain. When the valve 9 is cleaned by air blowing, the mold release agent is applied to the mold, and the mold is clamped, the state shown in FIG. 1 is obtained.

FIG. 2 shows another embodiment of the valve device section,
The valve stem 9a and the block 14 are separated from the shaft 15, and the shaft 15 is brought into contact with the block 14. Instead, a relatively weak compression spring 20 is inserted between the block 14 and the sleeve 11, which is a support member for the valve stem 9a.
A somewhat strong compression spring 22 was installed between the cover 21 holding the solenoid 10 and the end of the shaft 15. The valve 9 is connected to the shaft 1 by energizing the solenoid 10.
5 is moved to the right and the compression spring 20 is activated, it is tightened, and the solenoid 10 is demagnetized and the compression spring 22 is activated to open it.

In the embodiment described above, the valve 9 is actuated to pull it, but this can also be applied to a type in which the valve is pushed and closed.

FIG. 3 shows yet another embodiment of the present invention, in which the valve 9 is placed directly on the inner surface of the cavity 4.

In Fig. 3, 1 is a fixed plate, 2 is a fixed mold,
3 is a movable mold, 4 is a cavity, 5 is an injection cylinder, 6 is an injection plunger, 5a is an injection cylinder 5
6a is an injection sleeve, 9 is a gas discharge valve, 10 is a solenoid placed in the fixed mold 2, 11a is a valve seat, 13 is an exhaust port, and 17 is a compression ring. The spring 23 is wiring for the solenoid 10. In this case, since the valve 9 is attached directly to the surface of the cavity 4, the valve 9 is closed and the valve head 9b is attached to the fixed mold 2.
When the valve head 9 is pulled inward and comes into close contact with the valve seat 11a, the valve head 9
Cavity 4 whose outer surface b matches the desired product shape
It is made so that it can form part of the surface of. In that case, the outer surface of the valve head 9b may be flat or curved.

In the embodiment shown in FIG. 3, if the thickness of the cavity 4 at the part where the valve 9 is attached is thin, when the mold is clamped in the same manner as in the embodiment shown in FIGS. When the head 9b is brought into contact with the inner surface of the cavity 4 of the movable mold 3 and the mold is opened, the valve 9 can be further opened.
It is possible to make the air blowing more effective.

Of course, this valve 9 is connected to the cavity 4 of the movable mold 3.
It can be mounted on a surface, and the valve 9 can be installed not only horizontally parallel to the machine center, but also horizontally perpendicular to the machine center or vertically.

In this way, the present invention has the configuration described in the claims for utility model registration, so that a large amount of gas in the cavity can be sufficiently discharged through the gas exhaust valve during injection, and Immediately before the end of injection, the gas exhaust valve can be automatically closed to prevent the object to be injected from coming out of the mold. Furthermore, since the gas in the cavity can be reliably and easily discharged, a high-quality injection product that does not contain gas and has no cavities can be easily obtained.

In addition, since a solenoid device is used to operate the gas exhaust valve, the opening/closing stroke is short and the response time is also extremely short, allowing the gas exhaust valve to close quickly while the injection plunger is moving forward. In addition, the gas can be discharged reliably and easily, and the instruction timing of the operation instruction device that issues an operation instruction to the solenoid device while the injection plunger is moving forward can be easily adjusted.

In addition, in the present invention, in the valve installed in the part where the molten metal comes, a seat type valve seat is provided in which the valve head of the valve is seated on a member that supports the valve stem slidably in the axial direction. The head is firmly pressed against the valve seat every time. Therefore, in the present invention, as long as the valve is closed at the correct timing, the valve will not malfunction due to molten metal and can be used semi-permanently.

Furthermore, since the valve head and valve seat of the valve are located on the mold separation surface, the solidified metal formed by the molten metal solidifying on the outside of the valve head can be easily inserted into the mold together with the cast product. It can be taken out from

In addition, in the present invention, a spring is provided on the valve stem to act in the direction of opening the valve, and when the movable mold is in the clamped state in contact with the fixed mold, and the valve head is in the closed state due to the action of the spring. When the valve is opened by being pressed against a part of the mold, there is a gap between the member that slidably supports the valve and the block provided at the rear end of the valve head, which prevents the mold from opening. If a block is attached to the valve stem so that the valve can be opened wide by the action of the spring, when the mold is opened and the movable mold is separated from the fixed mold, the valve will open by the action of the spring. It will open wide and the valve head will be quite far away from the valve seat.
Therefore, it is very easy to clean the valve seat and the portion of the valve head that is in close contact with the valve seat from the outside or inside of the valve using air spray or the like. In addition, spraying air on the valve that is open when the mold is opened is
This is to ensure that even if small particles of solidified metal are attached to the valve seat or its surroundings, it will be blown away with air and will not interfere with the subsequent operation of the valve.

In addition, in the present invention, when the mold is clamped, the valve head is pushed by the action of the mold, and when the mold clamping is finished, the valve opening is adjusted to the appropriate state, and during injection, the valve head is pressed in the mold cavity 4. When the gas is exhausted quickly enough and the molten metal comes close to the valve, the valve should be closed quickly, in conjunction with the operation of the solenoid device, to prevent the molten metal from going inside the valve or outside the mold. can be done reliably and easily.

Furthermore, in the present invention, since a timer-based operation instruction device is used as an operation instruction device for closing the valve during injection, it can be easily incorporated into an injection device or an injection control device, and its adjustment can be easily performed. This can also be easily done at the control panel or operation panel.

Furthermore, when a timer is used as the operation instruction device, the timer can be easily adjusted using a control panel or operation panel, resulting in good operability and stable operation.

When implementing this invention, the effect will be further improved if it is used in combination with a reduced pressure injection method or a non-porous injection method in which the cavity is in an oxygen atmosphere.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, and FIGS. 2 and 3 are longitudinal cross-sectional views showing other embodiments of the present invention. 1... Fixed plate, 2... Fixed mold, 3... Movable mold, 4... Cavity, 5... Injection cylinder, 6
...Injection plunger, 8...Gas vent groove, 9...
Valve, 10... Solenoid, 11... Sleeve, 1
3...Exhaust port, 15...Shaft, 17, 20, 22...
...Compression spring, 26...Forward start command device, 27...
...Solenoid switching valve, 28...Timer.

Claims (1)

[Scope of utility model registration request] A degassing valve is provided in the cavity of the mold or in the part of the degassing groove led from the cavity where the molten metal comes, and the movable shaft of the solenoid device is attached to the rear end of the valve stem of this valve. A seat-type valve seat on which the valve head of the valve is seated is provided on a member that supports the valve stem so as to be slidable in the axial direction, and the valve is mounted on the valve stem. A spring is provided that acts in the opening direction, and the movable mold is in a clamped state in contact with the fixed mold, and
When the valve head is pressed against a part of the mold by the action of the spring and the valve is opened, the member that slidably supports the valve stem in the axial direction and the part on the rear end side of the valve stem There is a space between the block and the block installed in the part, and when the mold is opened, the block is attached to the valve stem so that the valve can be further opened by the action of a spring, and the block is attached to the valve stem, and the solenoid device is instructed to operate while the injection cylinder is moving forward. 1. A degassing device for a mold of an injection molding apparatus, wherein an operation instruction device is provided with a timer, and the solenoid device is actuated to close the valve in response to an electrical command generated by the operation of the operation instruction device.