JPS6023093Y2 - Gas venting device for mold - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a mold degassing device for extracting a large amount of gas from a mold cavity during injection in a die casting machine.

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. .

Therefore, a conventional method has been to place an openable/closable valve that can close the gas exhaust path in the gas exhaust path of the mold, and to close this valve by activating a solenoid when the gas during injection has completely escaped. was considered.

However, conventionally, during high-speed injection, several operating elements were involved between the time when the command position for closing the valve was detected by a limit switch and the time when the valve was actually closed, so the time in between was a little longer. Also, it was difficult to time the valve to close.

To begin with, in die casting, during low-speed injection and subsequent high-speed injection, the gas vent valve is opened to exhaust the gas inside the mold cavity, and the gas passes through the cavity and enters the gas exhaust path. Just before the molten metal reaches the valve,
It is necessary to close the valve as quickly as possible, but in order to fully vent the gas, it is necessary to issue a command to close the valve using a limit switch, etc., and activate the solenoid during high-speed injection after the gas in the cavity has been exhausted. There is.

However, high-speed injection is usually performed at a speed of 2 to 4 m/Sec in a short time of 0.05 to 0.1 seconds, and
Even if the cross-sectional area of the gas exhaust passage is increased, at most it will only be about 1/m of the cross-sectional area of the injection sleeve, so the speed of the molten metal traveling through the gas exhaust passage will be extremely high, at least m times the high-speed injection speed.

Therefore, in order to obtain good quality injection products without nests,
After the molten metal has sufficiently entered the gas exhaust passage from inside the cavity and the gas has been exhausted from the cavity, it is necessary to quickly close the valve before the molten metal jumps out of the gas vent valve.

As a result, the time required to close this valve needs to be extremely short, only 2 to 3 m/Sec.

In addition, if it takes a long time for the valve to close after the command to close the valve is issued, you can move the operating position of the limit switch etc. a little closer to you depending on the expected operation, but the valve will close slowly. If the inside of the cavity is evacuated before injection, the valve will be close to closing even when the degree of vacuum is high, so the vacuum capacity will drop and the specified vacuum capacity will not be obtained during injection. was there.

In particular, in conventional vacuum die casting, the opening and closing stroke of the valve was relatively long and the valve was tightened with a cylinder, so it took several seconds to close the valve, which caused the vacuum die casting to be unsatisfactory. It had not been done.

Further, when the valve is closed slowly, even if the degree of variation in the valve closing operation is constant, the amount of variation when the valve is actually closed becomes large, and the stability of the valve closing operation is also poor.

Therefore, as mentioned above, one important factor is how quickly the valve can be closed when a limit switch or other command is received during high-speed injection, but with conventional gas exhaust valves, this is not possible. , were not fully satisfied.

The present invention aims to eliminate these drawbacks.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, and the above-mentioned gas is discharged during the forward movement of the injection cylinder. The valve is closed as quickly and reliably as possible in a predetermined position to prevent the molten material to be injected from coming out of the valve, and it is possible to reliably and easily obtain a high-quality, strong, and void-free injection product. This is how it was done.

To this end, in the present invention, a gas exhaust valve that can be opened and closed is provided in the gas exhaust passage following the cavity provided between the molds or in the gas exhaust part of the cavity, and the valve stems of the valve are arranged at different outer diameters. The solenoid device is a solenoid device, which has a stepped valve stem with The rod is attached so that it can move forward and backward, and a member is installed on the rod part that applies force in the direction of pressing the rod against the valve stem, and the rod is engaged with the stepped part of the valve stem to open the valve. A position sensor is provided for commanding the valve to close while the injection cylinder is moving forward. This is a degassing device for molds in which the sensor and solenoid are directly connected only by a lead wire with a power supply in the middle.

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

Figures 1 and 2 show one embodiment of a die-casting machine, in which 1 is a fixed plate, 2 is a fixed mold, 3 is a movable mold, and 4 is a die-casting machine.
is the cavity, 5 is the injection cylinder, 7 is the injection cylinder 5
This is a striker attached to an injection plunger 6 that is integrally attached to the piston rod.

The movable mold 3 is fixed to the movable platen 8 side, and the extrusion plate 10 slides to the movable mold 3 side via a rod 9 operated by a pressing cylinder (not shown) provided on the movable platen 8 side. A plurality of extrusion pins 11 are fixed to this extrusion plate 10, and are slidably fitted into the movable mold 3 and serve to extrude the injection molded product. .

On the other hand, in this embodiment, a gas venting device 12 is attached to the upper separation surface of the movable mold 3.

This degassing device 12 has a structure as shown in an enlarged view in FIG.

The gas venting device 12 has a poppet-shaped valve 14 provided in a gas exhaust passage 13 continuous with the cavity 4.
The valve stem 15 of No. 4 is a fixed member 16 fixed to the movable mold 3 side.
It is slidably fitted in the mold opening direction.

A small diameter portion 17 is formed on the movable mold 3 side of the valve stem 15, and by forming this small diameter portion 17, the valve stem 1
A stepped portion 18 is formed in the middle of 5.

The poppet-shaped valve 14 has a short stroke and is ideal for increasing the gas passage area, shortens the operating time and can be closed quickly, and also provides a good seal so that the molten metal does not dissipate from the valve stem. You can prevent it from entering the 15 side.

Furthermore, since the valve 14 can be tightened in the gas venting direction, tightening is easy.

A nut-shaped spring receiver 19 is fixed to the end of the valve stem 15 on the movable mold 3 side, and this spring receiver 19 and the fixed member 1
A compression spring 20, which is a type of elastic body, is mounted between the valve 14 and the rear surface of the mold 6, and constantly biases the valve 14 so as to pull it toward the movable mold 3.

As is clear from FIG. 2, the valve head 14a of the valve 14 is formed on the fixed mold 2 side and has a structure that it can be positioned in a recess 21 continuous with the gas discharge path 13, An opening 22 formed on the third mold dividing surface 3a side has a valve seat 22a and faces the recess 21.

This opening 22 is an exhaust port 23 formed on the movable mold 3 side.
is connected to.

On the other hand, a solenoid 24 is fixed to the upper end surface of the fixed mold 3, and its rod 25 is fitted into a through hole 26 formed in the fixed member 16, and further passes through the fixed member 16 to form the stepped portion. 18.

When the tip of the rod 25 is engaged with the stepped portion 18, the valve head 14a fits into the recess 21, and the gas exhaust passage 13 and the exhaust port 23 are connected through the opening 22. The compression spring 20 is in a compressed state.

Note that if the compression spring 20 is a member that applies force in the direction of closing the valve 14, it can be used to pull the valve backward using a tension spring provided at another position, a cylinder, or gravity. It can also be replaced with other members.

Further, a spring receiver 27 that also serves as a stopper for regulating the lower limit of the rod 25 is provided in the middle of the rod 25, and between this spring receiver 27 and a boss 28 fixed to the open end of the through hole 26. is loaded with a compression spring 29, which constantly applies force to the rod 25 in the forward direction.

Therefore, if the solenoid 24 is energized in the open state shown in FIG. 2, the rod 25 will rise.
The engagement between the tip end of the valve stem 15 and the stepped portion 18 of the valve stem 15 is disengaged, and the valve 14 is quickly tightened by the action of the compression spring 20.

In this case, when the valve 14 is closed, the force of the compression spring 20 to tighten the valve 14 is slightly weakened, but when the valve 14 is open, the compression spring 20 is at maximum compression, so the force that tightens the valve 14 is extremely strong. This is very large compared to the force with which the valve is closed by the solenoid when the valve is directly connected by the action of a conventional solenoid, and therefore the valve 14 can be closed quickly.

Furthermore, by using the pressure wire spring 20, once the valve 14 is closed, it can be reliably kept closed until the valve 14 is opened by the action of the set hinge 30 as described later. ing.

Furthermore, since the valve 14 is designed to close when the engagement is disengaged, the valve 14 can be quickly tightened by simply moving the rod 25 by one turn due to the action of the solenoid 24. ing.

Note that once the rod 25 is moved back and the valve 14 is closed, the solenoid 24 can be demagnetized.

A reset pin 30 is fixed to the push-out plate 10 in parallel with the push-out pin 11 and facing the rear end of the valve stem 15 .

The reset pin 30 is set so as not to contact the rear end of the valve stem 15 when the valve 14 is closed and the valve stem 15 is in a retracted state.

By the way, the contact between the rod 25 and the stepped portion 18 of the valve stem 15 is not a direct contact by the rod 25, but as shown in FIG.
The contact may be indirect via a steel ball 31 as shown in FIG.

Further, the stepped portion 18 does not necessarily need to be provided only on the valve stem 14 itself, but may be provided on a part that moves integrally with the valve stem 14, for example, a nut-shaped spring receiver 19 as shown in FIG.
It can also be provided in

Further, the valve stem 15 has a stepped portion 18 as shown in FIGS.
In addition to this structure, a groove or a hole into which the tip of the rod 25 can fit may be provided in a part of the valve stem 15.
A protrusion may be provided on a part or the entire circumference of the protrusion so that the tip of the rod 25 can be placed against the rear end surface of the protrusion.

However, in the present invention, the valve 14, such as the spring receiver 19,
Components other than the valve stem 14 itself that move in the same manner as
It shall be included in the valve stem.

On the other hand, an injection stroke detector such as a limit switch 32 or a proximity switch, that is, a position sensor, which serves as an injection stroke detector during injection, is installed at a position in contact with the striker 7 integrated with the plunger 6. This limit switch 32 and the solenoid 24 are connected via lead wires 33 and 34, and a power source 35 is provided in the middle of the lead wire 33.

In the state shown in FIG. 1, the limit switch 32 is in contact with the striker 7 and is in an OFF state.

Note that 36 is an injection sleeve and 37 is a molten metal.

The reason why the solenoid 24 device directly connected to the limit switch 32 is used to close the gas discharge valve 14 while the injection plunger 6 is moving forward is that the operating stroke of the solenoid 24 device is, in this case, about 1TIrIIL, for example. It is extremely short, and in combination with the action of a member such as the compression spring 20 that applies a force in the direction of closing the valve 14, the time required for the closing operation of the valve 14 can be extremely reduced;
Also, it has extremely good responsiveness and operates quickly.

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

First, as shown in Fig. 1, the fixed mold 2 and the movable mold 3
In the closed state, a predetermined amount of molten metal 3 is poured into the injection sleeve 36.
7 and turn on the injection start switch (not shown).

Then, the injection cylinder 5 operates, the plunger 6 moves forward, and the molten metal 37 is transferred from the injection sleeve 36 to the cavity 4.
Cast at low speed followed by high speed.

As the plunger 6 moves forward, the striker 7 integrated with it
If the time when the striker 7 moves forward and the striker 7 comes off the limit switch 32 is set to be when the cavity 4 is filled with molten metal and the gas inside the cavity is discharged in the direction of the gas exhaust path 13, the limit switch 32 is turned on. At the same time, the solenoid 24 is energized, the rod 25 is attracted and retreats, and the engagement between the tip of the rod 25 and the stepped portion 18 is released.
The valve 14 is retracted by the elastic force of the compression spring 20, and the valve 14 closes the opening 22, completely preventing the molten metal 37 from ejecting from the exhaust port 23.

In this case, as described above, the engaging portion is released by raising the rod 25 slightly by about 11ra using the solenoid 24. At that time, the valve 14 is pulled backward by the action of the compression spring 20, so the limit switch 32 issues a command. The valve 14 is closed in an extremely short time, for example, at 377LSeC, until the valve 14 is completely closed.

Since the gas in the cavity 4 has been completely exhausted by the time the valve 14 is closed, there is no problem such as gas mixing into the product and the formation of cavities.

After the injection is completed and a predetermined cooling time has elapsed, the mold is opened, the extrusion plate 10 advances, and the extrusion pin 11 extrudes the product. At the same time, the reset pin 30 also advances and the valve stem 15 Push the rear end to move the valve 14 forward.

At this time, the solenoid 24 is already de-energized, and the rod 25, which is given a force in the forward direction by the compression spring 29, is engaged with the stepped portion 18, and the valve 14 is opened at the opening. 22 is reset to the open state and is in a state of waiting for the next molding operation.

Note that if the amount of protrusion of the valve 14 by the reset pin 30 is set to be larger than that in the reset state during product extrusion, cleaning by gas blowing or the like on the gas venting device 12 side becomes easier.

Figure 4 is for explaining another embodiment of the present invention.
The same parts as those in Figures 1 to 3 are given the same reference numerals, and their explanations will be omitted.

This embodiment employs a structure in which the gas in the cavity is forcibly discharged by an exhaust device, which is a vacuum generating device, and a structure in which a gas venting device is used in combination.

That is, an exhaust pipe 38 is provided continuously to the exhaust port 23, a branch pipe 39 is provided in the middle of this exhaust pipe 38, and a lid 40 that can be opened and closed is provided at the open end of this branch pipe 39.

An electromagnetic switching valve 43 is provided in the middle of a pipe 42 connecting the exhaust pipe 38 and the exhaust device 41.

Along with the limit switch 32, a limit switch 44, which is a stroke detector for a vacuum start command, is provided at a position away from the plunger 6 in the backward direction.

The limit switch 44 is located at a position where the limit switch 44 is released from contact with the striker 7 and turned ON immediately before switching from an initial low-speed injection to a high-speed injection in a normal injection molding method.

This limit switch 44 is connected to the power source 35 and also to the lead wire 33 via a lead wire 45. A timer 46 is arranged in the middle of this lead wire 45, A switch 47 is disposed between the solenoid 43a of the electromagnetic switching valve 43 and is turned off by the action of a timer 46, and a portion of the lead wire 33 is connected to the solenoid 43a of the electromagnetic switching valve 43. .

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

Before starting injection, limit switch 32.4
4 is in the OFF state, mold clamping is performed in this state, the gas venting device 12 is in the open state, and the electromagnetic switching valve 43 is in the OFF state.
It is in FF state.

In this state, first, low-speed injection is performed.

The injection cylinder 5 is activated, the plunger 6 moves forward, and the molten metal 37 begins to be supplied into the cavity.

Eventually, when the limit switch 44 and the striker 7 come out of contact and the state is just before the start of high-speed injection, the limit switch 44 is turned on, the electromagnetic switching valve 43 is also turned on, and the gas in the cavity 4 is exhausted through the pipe 42. Device 4
1, it is forcibly ejected.

At this time, the lid 40 is closed due to negative pressure.

In this state, the limit switch 32 is still in the OFF state, the valve 14 is in the open state, and vacuum suction is continued.

When the limit switch 44 is turned on, the timer 46 starts counting, and soon, the plunger 6 moves forward at high speed, and the molten metal 37 is supplied into the cavity 4. As the molten metal 37 moves forward, the remaining amount discharged by the action of the exhaust device 41 is removed. Even very small amounts of gas are discharged to the outside through valve 14.

When the molten metal 37 reaches the gas discharge path 13, the contact between the striker 7 and the limit switch 32 is broken, so the solenoid 24 is activated and the compression spring 20 is activated.
The valve 14 closes quickly before the molten metal 37 reaches the valve 14 section.

After that, the timer 46 counts out and the switch 47
is turned off, so the electromagnetic switching valve 43 is also turned off,
It is cut off from the vacuum source.

In this way, the gas is forcibly discharged by vacuum suction, so that no gas in the cavity is mixed into the product, making it possible to obtain a good injection product.

After injection molding, the mold is opened, the product is extruded by the extrusion pin 11, the plunger 6 is retracted, the limit switches 32 and 44 are turned off, and the timer 46 is reset to wait for the next molding operation. state.

As is clear from the above explanation, according to the present invention, since the structure is as described in the claims for utility model registration,
During injection of molten metal, a large amount of gas in the cavity can be sufficiently discharged through the gas exhaust valve, and the gas exhaust valve can be automatically closed just before injection ends, allowing the molten metal to escape from the mold. can be completely prevented from appearing.

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 reliably and easily obtained.

In the present invention, the position sensor and solenoid are directly connected only with a lead wire that has a power supply in the middle, so that the solenoid is immediately activated by the operation of the position sensor that gives the command to close the valve during injection. After receiving the command, the valve can be quickly closed.

In addition, in the present invention, in order to close the gas discharge valve,
The valve stem has a stepped part that is engaged with a rod that retreats under the action of a solenoid, and members such as a compression spring that biases the valve in the direction of closing the valve are used, so the rod stops the valve stem. It is sufficient to engage the valve only slightly, and the rod only needs to be retracted by a small amount of about 171rIrL due to the action of the thread maid, and if the rod is disengaged, the valve can be tightened by the action of a member such as a compression spring.

Therefore, the movement stroke of the rod by the solenoid can be extremely short, and the engagement between the rod and valve stem can be achieved quickly, and the force that pulls the valve is greater when the stroke is longer than when the solenoid is energized. The valve can be pulled by the action of a compression spring, etc.
The valve can be quickly closed after receiving a command to close the valve.

Furthermore, once a valve is tightened by a compression spring, etc., the valve will not open until it is opened by the action of a reset pin, etc.
Since the valve can be kept reliably closed,
Even if intermittent molten metal comes to the valve part, the valve once closed will not open, and therefore molten metal will not enter beyond the valve head, and the valve will not malfunction.

Of course, even if the solenoid flaps, it has no effect.

Also, the gas exhaust valve can be quickly closed during the high speed advancement of the injection plunger, thus ensuring gas exhaustion.
In addition to being easy to carry out, it is also easy to adjust the position of the stroke detector and the timing of the actuation command, which give an actuation command to the solenoid device while the injection plunger is moving forward at high speed.

Note that when the present invention is used in combination with a vacuum die-casting method, a predetermined vacuum capacity can be easily obtained by closing the valve very quickly.

Furthermore, by quickly closing the valve, stability in the valve closing operation can be achieved.

Note that at the start of operation, injection is usually performed only at low speed in order to raise the mold temperature and protect the mold, but at this time the inertia of the molten metal is weak, so the valve does not close and the valve There is a risk of molten metal getting into the rod.

However, since the present invention uses a solenoid, in such a case, the valve can be closed in advance by activating the solenoid using a changeover switch or the like.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing one embodiment of the present invention, Fig. 2 is an enlarged sectional view of the degassing device portion of Fig. 1, and Figs. 3 a and b.
4 is a longitudinal sectional view showing another embodiment of the engagement structure of the stepped portion of the rod and valve stem of the gas venting device, and FIG. 4 is a longitudinal sectional view showing another embodiment of the present invention. 1...Fixed plate, 2...Fixed mold, 3.
...Movable mold, 4...Cavity, 5.
...Injection cylinder, 6...Plunger,
7... Suiraika, 8... Movable board, 1
1... Push-out pin, 12... Gas venting device, 13... Gas discharge path, 14... Valve, 15... Valve stem. , 18...Stepped portion, 2
0,29...Compression spring, 23...Exhaust port, 24...Solenoid, 25.Bend/Rod.
30...Reset pin, 32,44...
・Limit switch, 35...Power supply, 41...
...Exhaust device.

Claims (1)

[Scope of Claim for Utility Model Registration] A gas exhaust valve that can be opened and closed is provided in the gas exhaust passage following the cavity provided between the molds or in the gas exhaust part of the cavity, and the valve stem of the valve has different outer diameters. The solenoid device is a solenoid device, which has a stepped valve stem with To install the rod so that it can move forward and backward, a member is installed on the rod part that applies force in the direction of pressing the rod against the valve stem, and the rod is engaged with the stepped part of the valve stem to open the valve. A position sensor is provided for commanding the valve to close while the injection cylinder is moving forward. A degassing device for molds that directly connects the sensor and solenoid with only a lead wire that has a power source in between.