JPS58112646A - Method and device for die casting - Google Patents

Abstract

PURPOSE:To prevent the intrusion of molten metal into a valve device surely by providing mechanisms which close a vent valve connected to cavities by the effect of the inertial force of the molten metal in the stage of injection and close the same by the effect of a solenoid device as well. CONSTITUTION:An injection cylinder 7 is operated to supply molten metal into cavities 8. The molten metal filling the inside of the cavities 8 flows through a vent groove 9 and enters a vent device 10 from which the gas is discharged to the outside; thereafter, the vent valve is closed by the effect of the inertial force of the molten metal. On the other hand, the injection speed of the molten metal is detected by an injection speed sensor 33, and the prescribed injection speed of a setter 37 and the detected speed are compared in a comparator 36. When the injection speed does not attain the speed necessary to close the vent valve, a solenoid 21 is immediately energized to close the valve automatically. Thus the failure of the valve device by the intrusion of the molten metal into the valve is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a die casting method and apparatus in which injection is performed using a mold gas venting device that extracts a large amount of gas from a mold cavity during injection.

Traditionally, when die-casting machines inject molten metal into the mold cavity at high speed and high pressure, the gas in the cavity cannot be sufficiently released and remains in the product, resulting in the formation of cavities in the product. .

Therefore, conventionally, a method has been considered in which an openable/closable valve capable of closing the gas exhaust passage is disposed in the gas exhaust passage of the mold, and this valve is closed by the action of the inertial force of the molten metal during injection.

However, in a die-casting machine, when starting operation,
In order to raise the mold temperature and protect the mold, injection is often performed only at low speed. At that time, since the inertia of the molten metal was weak, the gas vent valve would not close, and there was a risk that molten metal would enter the valve device. Conventionally, the valve was pressed manually each time, or
Alternatively, the gas vent groove in front of the valve was operated with something like a piece of aluminum cut out.

In addition, if a problem occurs in the hydraulic system or electrical system during injection, or if the plunger tip gets stuck against the injection sleeve, the specified high injection speed cannot be obtained. The degassing valve did not close due to the action of molten metal, and molten metal entered the valve device, causing problems in operation.

The present invention aims to eliminate these drawbacks, and when a predetermined high injection speed cannot be obtained, the valve is closed by the action of a solenoid device instead of attempting to close by the inertia of the molten metal. This prevents molten metal from entering the valve device.

Next, the present invention will be explained with reference to an embodiment shown in the drawings.

In Fig. 1, 1 is a fixed plate, 2 is a movable plate, 3 is a fixed mold, 4 is a movable mold, 5 is an injection sleeve, 6 is an injection plunger, 7 is an injection cylinder, 8 is a cavity, and 9 is a gas cylinder. The groove 10 is a degassing device provided at the separation surface between the fixed mold 3 and the movable mold 4. However, the fixed portion of the degassing device 1o was fixed to one of the molds, such as the fixed mold 1, for example.

As shown in FIG. 2, the gas venting device 1o is provided with a valve 11 so that the lower surface of the valve head 11a is substantially perpendicular to the gas handling groove 9, and from the middle of the gas venting stage 9, the valve head 11a
A gas exhaust passage 12 is provided, which consists of a vise that detours laterally to reach one side of the valve head 11a.

In the spool 13, which is a valve support member, the valve 11 includes:
When the valve 11 slides in the axial direction of the spool 13 and moves upward, the valve head 11a comes into contact with the valve seat 13a provided at the lower end of the spool 13, and the passage 12
The communication state with the valve chamber 14 in the valve chamber 3 is closed. The valve chamber 14 has an exhaust port 15.

An elastic body 15 such as a tension spring is provided between the upper end of the valve 11 and the spool 13, and the elastic body 15 is such as a tension spring that applies force in the upward direction of the valve 11 to close it. On the other hand, there is provided a locking side 16 that stops at the lower position, that is, the individual position, and is unlatched by the closing operation of the valve 11 due to the impact 'l+' exerted on the valve 11 by the molten metal.

The locking mechanism 16 includes a steel ball 2 whose pressing force can be adjusted via a compression spring 19 using a nut 17 and a rod 18.
0 and a solenoid 21 connected to the rod 18, and this steel ball 2o is pressed against a stepped portion 22 provided on the outer peripheral surface of the valve stem 11b. The locking mechanism 16 with such a structure is provided so that even if the molten metal advances to the valve 11 intermittently, the valve 11 will be securely closed during the first operation and will not open again during the - times of injection. This is to ensure that.

Note that instead of the above-mentioned elastic body 15, a cylinder or the like that applies a relatively small force can be used as a device that applies a force in the direction of sliding the valve 11 upward and closing it. . If a cylinder is used here, it is not necessary to provide a valve opening device consisting of a return mechanism 23 and a stone 24, which will be described later.

The spool 13 containing the valve 11 can be moved in the axial direction by actuation of a piston rod 27 of a cylinder 26 attached to, for example, the fixed mold 3 via a bracket 1@5.

A stopper mechanism is provided in order to more reliably open the valve 11 when lifting the spool 13, or for empty firing. That is, the return punch 23 was made to protrude horizontally from the block 28 attached to the valve stem 11b. Return pestle 2
Reference numeral 3 denotes a passage through a through hole 29 provided in the peripheral wall of the spool 13 to the outside of the spool 11. When the spool 11 is placed on its back in the cylinder 26, the spool 1 to the collar 24 attached to the bracket 25 are inserted. As the spool 13 rises,
There is a device that lowers the valve 11 relative to the spool 11.

On the other hand, as shown in FIG. 1, between the striker 30 that moves integrally with the injection plunger 6 and a fixed part such as the injection cylinder 7, there is a photo sensor made of a light blocking piece 31 and a phototube section 32, etc. A speed platform detection sensor 33 is provided. The phototube section 32 is provided in the middle of the high-speed injection command area, and detects whether a predetermined injection speed is being achieved at a predetermined position where the high-speed injection command is issued. 34 is a limit switch for high-speed injection command, and 35 is a limit switch for confirming the backward limit of the injection cylinder. Note that the speed detection sensor that operates after a high-speed injection command and before the completion of filling is not limited to a photo sensor, and may also be any other conventionally known device that combines a Magnescale and a timer. A comparator 37 for determining the injection speed and comparing it with a reference value is a setting device for closing the valve 11 when a predetermined injection speed has not been reached. Then, for example, the setting device 37 sets the speed a1.
If 1Il/SeC is set, if the speed in the high-speed injection command range is less than 1m/sea, the solenoid 21
is immediately energized, valve 11 closes, and its speed becomes 11/S.
If the temperature exceeds ec, the solenoid 21 is not energized, so that the valve 11 is closed only by the action of the inertial force of the molten metal.

Reference numeral 38 denotes a changeover switch for operating the solenoid, which selects whether or not the input from the speed detection sensor 33 is used as a determining factor for the excitation/de-excitation command of the solenoid 21c.

However, in the changeover switch 38, regardless of other factors,
Alternatively, the solenoid 21 may be energized in advance to close the valve 11, or the solenoid 21 may be deenergized in advance so that the valve 11 is closed only by the inertia of the molten metal. I made it possible to choose.

Next, the method of the present invention will be explained together with the operation of this embodiment configured as described above.

First, with the mold open, the spool 13 is lowered by the cylinder 26 with the stepped portion 22 of the valve stem 11b pressing the spool ball 20. When the fixed mold 3 and the movable mold 4 are clamped in this state, a passage is formed from the cavity 8 to the outside of the spool 13 via the gas vent groove 9, the passage 12, and the valve chamber 14.

First, the solenoid 21 is deenergized by selecting the changeover switch 38. In this state, the injection cylinder 7
is activated, and molten metal is supplied into the cavity 8. At this time, the inside of cavity 8 is filled with 4 tons! The molten metal is treated as a gas.
The gas in cavity 8 passes through passage 1.
2 and the valve chamber 14, and is discharged to the outside. 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 comes into contact with the lower surface of the valve head 11a. At this time, the impact applied to the valve 11 is much larger than the impact applied by the gas to the valve 11, since the mass of the molten metal is extremely large compared to the gas, and its inertia is large, causing the valve 11 to be thrown upward. As a result, the upper surface of the valve head 11a is
3a, and closes the space between the passage 12 and the valve chamber 14, and stops the outflow of the molten metal at the valve 11 position. At this time, even if the molten metal mixes with the gas in the gas vent groove 9 and hits the valve body discontinuously in the form of droplets, the first collision of the molten metal will cause the valve body to be thrown up, and then the gas will come. Even when the upward pressing force from the molten metal is removed, the valve 11 is maintained in the upper position by the action of the elastic body 15, so that the exhaust passage is reliably closed by the valve 11.

At this time, since the spool 13 is securely fitted to the mold, it will not move in the axial direction even if a large force is applied by the molten metal.

Note that the molten metal that has entered the bypass-like gas discharge passage 12 advances to the side of the valve 11 and is shut off by the closed valve 11, but at this time, the molten metal flows through the bypass passage of the passage 12 itself and Due to the action of the sag and reservoir part 12a provided in the middle of the passage 12, it takes a sufficiently longer time than the time for the valve 11 to narrow to reach the side part of the valve 11, so that mts reaches the side part of the valve v14 in the spool 13. It is extremely rare for the mold to progress inside or outside the mold.

When the casting operation is completed by pressurized cooling for a predetermined period of time with the valve 11 of the gas venting device 10 closed, the mold is opened, and then the cylinder 26 is operated to raise the spool 13. The valve 11 is separated from the solidified metal filling the cavity 8, the gas vent groove 9, and the passage 12, and the molded product is taken out from the movable mold by a product extrusion device (not shown).

Note that by operating the cylinder 26, the valve 11 is connected to the spool 13.
When raising the valve head 11a and the gas vent groove 9 together,
Since the valve 11 is prevented from moving upward due to separation resistance from the solidified metal in the passage 12, when the spool 13 attempts to rise, the spool is moved so that the valve 11 is pulled down from the spool 13 due to the above-mentioned resistance. 13, the steel ball 20 is located below the stepped portion 22.

Of course, the return punch 23 and the stopper 24 act to make this valve opening operation more reliable. Spool 1 like this
Since the valve 11 is located at a lower position within the spool 13 when pulling up the spool 13 during the next casting
When lowered, the valve 11 communicates the gas vent groove 9 and the passage 12 with the valve chamber 14, completing preparation for the next casting.

During normal injection, the comparator 36 and the like are operated by the changeover switch 38, so that the excitation/de-excitation of the solenoid 21 can be controlled in accordance with the operation of the speed detection sensor 33.

By doing so, the injection speed can be detected by the speed detection sensor at an appropriate position or time after the high-speed injection start signal is issued, and the predetermined injection speed can be set by the setter 37. Since the instructions are given, these values are sent to comparator 3.
6, and based on the comparison, a command is given or not given to the solenoid 21. If a predetermined injection speed necessary for closing the valve 11 is not achieved at a predetermined position or time after the high-speed injection start signal is issued, the solenoid 21 is immediately energized. that way,
The valve 11 is automatically closed before the molten metal reaches the valve 11 part.

In addition, from the high-speed injection start position, the valve 11 is closed due to the inertia of the molten metal.
For example, the injection plungero is 2001
111 When moving forward, the position at which to detect whether or not a high injection speed is occurring is approximately 50I from the high speed injection start position.
I'll leave it for later. If it is detected that the predetermined high injection speed is not reached at this point, the solenoid 21 is immediately energized as described above, but during this time, the distance that the injection 1 langier 6 moves forward until the valve 11 closes is Although it varies depending on the speed, it is approximately 1"□ mn. Therefore, the valve 11 can be reliably closed in advance before the melt reaches the valve 11.

In addition, when it is necessary to cast only with low-speed injection, such as when the mold temperature has not reached the predetermined temperature, such as when starting the operation of the die-casting mason, the selector switch 3
8 and close the valve 11 in advance by energizing the solenoid 21 before the injection star.

In addition, if this device is used, it is also possible to close the valve 11 by detecting the position of the injection stroke.

In this way, in the present invention, as described in the claims, when the injection speed is such that the degassing valve cannot be closed due to the action of the inertial force of the molten metal,
The valve can be closed immediately or previously by actuating the solenoid, so that no molten metal enters the valve arrangement during injection. Therefore, the injection operation is performed smoothly every time, and there is no need to replace the valve device or clean it more than necessary.

Furthermore, by using the gas venting device of the present invention, a large amount of gas in the cavity can be sufficiently exhausted through the gas exhaust mk during normal injection, and the gas can be exhausted immediately before the end of injection. The valve can close automatically,
It is possible to completely prevent molten metal 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 reliably and easily obtained.

In addition, in order to close the gas discharge valve, the first part of the stage I, which is engaged with the solenoid and the rod that retreats under the action of the solenoid, is
If you use a member such as a #4 valve stem and an elastic body that applies force in the direction of closing the valve, the rod only needs to be engaged so that the valve stem is in the 1st position, and the solenoid will cause the rod to move 111
Only a slight retraction of about 11 degrees is required, and once the rod is disengaged, the valve can be tightened by the action of a member such as an elastic body.

Therefore, the movement of the rod by the solenoid []−
The length can also be extremely short, the engagement between the rod and the valve stem can be quickly disengaged, and the valve can be quickly closed after receiving a command to close the valve.

A. Also, the valve can be tightened with an elastic body, etc., and once the valve is tightened, it can be kept reliably closed until the valve is opened by the action of a valve opening device, etc., so the valve part Even if there is intermittent hot water, the squeaking valve will not open,
Therefore, the molten metal will not penetrate beyond the valve head, and the valve will not malfunction.

In addition, gas exhaust can be reliably and easily discharged while the injection plunger is moving forward at high speed, and the injection plunger can issue an operation command to close the valve to the solenoid device during the forward movement when the injection plunger has not reached a predetermined high speed injection speed. It is easy to adjust the installation position of the speed measuring device and the timing of operation instructions.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view and control block diagram showing one embodiment of the apparatus for carrying out the method of the present invention, and FIG.
It is an enlarged sectional view of the degassing device part of the figure. 1...Fixed plate, 2...Movable plate, 3...Fixed mold,
4...Fashionable umbrella, box type, 5...Injection sleeve, 6...
Injection plunger... Injection cylinder, 8... Cavity, 9... Gas venting groove, 10... Gas venting device, 11... Valve, 13... Sprue, 15...・
Elastic body, 16... Locking mechanism, 21... Solenoid,
26...Cylinder, 3o...Striker, 33...
・Speed detection sensor, 36... Comparator, 37... Setting device, 38... Changeover switch Patent applicant Ube Industries, Ltd.

Claims (5)

[Claims] (1) The gas vent valve installed in the gas vent groove led from the cavity of the separation surface of the mold is closed by the action of the inertia of the molten metal during injection, and the solenoid is activated based on the closing command. A die-casting method that performs injection so that it can be closed by the action of a device. (2) Detect whether or not the injection speed exceeds a predetermined value during high-speed injection, and if the injection speed exceeds the predetermined value,
A patent claim in which the gas venting valve is closed by the inertia of the molten metal, and when the injection speed is not higher than a predetermined value, the gas venting valve is closed by the action of a solenoid device to perform injection. The die-casting method described in item 1. (3) For gas venting, the gas venting groove led from the cavity of the separation surface of the mold has a valve that is closed by the inertial force of the molten metal during injection, and also closed by the action of a solenoid device based on a closing command. Duncast device with valve device. (4) Claim 3, comprising an injection speed measuring device in the high-speed injection command area, and a device that issues a closing command to the solenoid device when the injection speed detected by the injection speed measuring device is smaller than a predetermined speed. The die-casting device described in section. (5) In a valve device for handling gas, a valve that slides in the axial direction and a first member that applies force in the direction of closing the valve are locked in the open position, and as the valve closes, the valve is locked in the open position. 5. A die-casting apparatus according to claim 3, comprising a second member that releases the lock by locking, and a solenoid device that is engaged with the second member.