JPH0254184B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic hot water supply method in a die casting machine.

Conventionally, in a vertical die casting machine, when feeding molten metal such as aluminum alloy into the injection sleeve with a ladle, a ladle 1 having a shape as shown in Fig. 1 is used, and the ladle 1 is rotated above the injection sleeve 2. The molten metal was dropped into the injection sleeve 2 by moving the molten metal. In this case, the height from the discharge port 1a of the ladle 1 to the top surface of the plunger tip 3, which is the point at which the molten metal falls, is relatively high, and when the molten metal is supplied into the injection sleeve 2, it swirls as shown in the figure. was. As a result, the molten metal is disturbed and comes into contact with air, which increases aluminum oxide, increases the amount of air involved, and lowers the temperature of the molten metal, leading to defective injection products.

The present invention is aimed at eliminating these drawbacks, and is designed to reduce the amount of molten metal coming into contact with air when feeding into the injection sleeve, and also to prevent air from being drawn in so that hot water can be fed quietly. It is something.

In the present invention, a ladle provided at the lower end that can open and close the molten metal inlet is used, and with the molten metal poured into the ladle and the molten metal inlet closed, the lower end of the ladle is inserted into the injection sleeve until it reaches the lower part. In this state, the molten metal inlet is opened and the molten metal in the ladle begins to be discharged into the injection sleeve, and when the upper surface of the molten metal in the injection sleeve discharged from the ladle becomes higher than the position of the molten metal inlet in the ladle, the ladle is opened. When raising the molten metal, it detects the descending state of the surface of the molten metal in the ladle,
The ladle was raised based on the detection status.

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

In FIG. 2, 2 is an injection sleeve, and 3 is a plunger tip that slides vertically within the injection sleeve 2.

The hot water supply ladle 1 has an injection sleeve 2 at its lower end.
It has a slightly elongated shape so that it can be inserted inside, and a melting spout 4 is provided at the lower end, and the melting spout 4 can be opened and closed with a valve rod 5. 1b is a hole through which air enters and exits.
6 is a cylinder for moving the valve stem 5 up and down, and is attached to the top of the ladle 1. 7 is a link that rotates around the other end (not shown); 8 is a chain wheel rotatably attached to the tip of link 7 by a shaft 9; 10 is chain wheel 8 and link 7;
The chain 11 is a bracket that integrally connects the chain wheel 8 and the cylinder 6, and the link 7, the chain wheel 8, the chain 10, etc. are ladle conveyed. A device 12 is formed.

Inside the ladle 1, a detection rod 14 for detecting the molten metal surface is suspended by a nut 13 or the like through the upper wall of the ladle 1, and the detection rod 14 is provided so as to be set at a desired position in the vertical direction. A power shielding member is provided between the upper wall of the ladle 1 and the detection rod 14. When the molten metal is discharged, it is detected that the surface of the molten metal in the ladle 1 has fallen by a desired amount, and a detection signal can be output.
Of course, when a predetermined amount of molten metal is in the ladle 1, the lower part of the detection rod 14 is immersed in the molten metal and is energized, so the surface of the molten metal goes down and the detection rod 1
4 and when the current is no longer applied, it is detected that the molten metal level in the ladle 1 has fallen by a predetermined amount. The lower end position of the detection rod 14 is such that when the ladle 1 is inserted to the lower part of the injection sleeve 2 and the molten metal in the ladle 1 starts to be discharged, the upper surface of the molten metal discharged into the injection sleeve 2 is at the lower end of the ladle 1. The position is set so that the detection rod 14 is activated when the metal reaches a little above the molten metal spout 4.

15 is a detection rod for detecting the molten metal level some time before the molten metal in the ladle 1 is finished being discharged; 16 is a nut; the detection rod 15 is provided so that its position in the vertical direction can be adjusted. The detection rod 15 detects this because when the amount of molten metal in the ladle 1 decreases, the degree of descent of the molten metal surface in the ladle 1 slows down, and the rising speed of the ladle 1 also slows down, which lengthens the hot water supply time. In order to avoid this, it has the role of detecting when the amount of molten metal remaining in the ladle 1 is getting low and emitting a signal to lift the ladle 1 relatively quickly.
Of course, if the lower end of the detection rod 15 is placed close to the supply port 4, it is also possible to detect that most of the molten metal has been discharged from the supply port 4.

Note that other detection methods may be used for these detection rods 14 and 15 as long as they detect the falling state of the hot water level in the ladle 1.

When supplying molten metal into the injection sleeve 2, first put the lower part of the ladle 1 into the molten metal in a furnace (not shown), position the molten metal inlet 4 below the surface oxide film of the molten metal, and then open the cylinder 6. The valve is actuated to raise the valve rod 5, and a desired amount of molten metal is poured into the ladle 1 from the molten metal spout 4. In this case, the amount of hot water supplied is determined by the vertical position of the ladle 1 with respect to the surface of the molten metal in the furnace. Fixing the ladle 1 at a predetermined position in the furnace and determining the amount of hot water to be supplied can be controlled by the action of a conventionally known electrode rod (not shown) attached to the ladle 1 or the like.

Once the desired amount of molten metal has been pumped into the ladle 1, the valve stem 5 is lowered by the action of the cylinder 6 to close the molten metal inlet 4, and the ladle 1 is moved by the action of the ladle conveying device 12, as shown in FIG. As shown, ladle 1
Insert the lower part of the injection sleeve 2 into the injection sleeve 2 in the standby position. At this time, the melt spout 4 at the lower end of the ladle 1 was positioned immediately below the plunger tip 3 located at the lower part of the injection sleeve 2. At this time, the distance between the molten metal spout 4 at the lower end of the ladle 1 and the plunger tip 3 varies depending on the height of the molten metal in the ladle 1 and the area of the molten metal spout 4;
The distance was set to ~10 mm, which is relatively small enough to prevent air from being drawn into the molten metal when it flows out.

In this state, the cylinder 6 is operated, the valve stem 5 is raised to open the molten metal spout 4, and the molten metal in the ladle 1 begins to be discharged into the injection sleeve 2. This state is the third
Shown in Figure a. If the ladle 1 is left stationary, the molten metal will be discharged from the molten spout 4 one after another, and the molten metal in the injection sleeve 2 will be gradually pushed by new molten metal from below without stirring the surface layer. The upper surface of the molten metal in the injection sleeve 2 will soon be above the position of the molten metal spout 4 at the lower end of the ladle 1. The upper surface of the molten metal in the injection sleeve 2 is the molten metal inlet 4.
Detection that the molten metal has risen slightly above the position, for example, by about 5 to 10 mm, is indirectly performed by detecting the amount of descent of the molten metal surface in the ladle 1 using the detection rod 14. However, this detection can also be performed indirectly using a timer that starts counting after the cylinder 6 is activated and the molten metal in the ladle 1 begins to be discharged, or by using a conventionally known detection rod or the like. It is also possible to directly detect the upper surface of the molten metal in the injection sleeve 2.

The upper surface of the molten metal in the injection sleeve 2 is at the ladle 1.
When a signal indicating that the ladle 1 is slightly higher than the position of the molten metal inlet 4 is issued, the ladle 1 starts to be raised with the molten metal inlet 4 open.

When the ladle 1 is raised while discharging the molten metal, the ladle 1 is raised in accordance with the discharge state of the molten metal, so that the molten metal inlet 4 and the molten metal discharged from the molten metal inlet 4 are always sequentially applied to the upper surface of the molten metal in the injection sleeve 2. Supply hot water in the same condition as when it is placed. At this time, Fig. 3b
As shown in , a state in which the upper surface of the molten metal in the injection sleeve 2 sequentially discharged from the ladle 1 is always located above and near the molten metal inlet 4;
For example, it is possible to keep raising the ladle 1 so that it is always about 5 to 10 mm above, or in some cases, the molten metal can be kept higher than the upper surface of the molten metal in the injection sleeve 2, which is sequentially discharged from the ladle 1. It is also possible to continue raising the ladle 1 while keeping the mouth 4 slightly above or at almost the same height. Of course, a combination of both can also be used.

As a method for raising the ladle 1 with the upper surface of the molten metal in the injection sleeve 2 always located at the molten metal inlet 4 when the ladle 1 is raised, the upper surface of the molten metal in the ladle 1 and the upper surface of the molten metal in the injection sleeve 2 A method is to set in advance a head-raddle rising speed curve consisting of a predetermined function such that the rising speed of the ladle 1 becomes slower as the head between the two becomes smaller, and to raise the ladle 1 sequentially according to the curve. There are methods such as raising the ladle 1 while constantly monitoring the hot water level. Note that the head measurement may be performed in terms of time, or may be performed using a light measuring device, a detection rod made of electrodes, or the like.

To constantly monitor the molten metal level, you can install several detection rods at different mounting heights in the ladle 1, or install a sensor rod that increases or decreases the current flowing depending on the height of the rod touching the molten metal surface. There is a method of monitoring the hot water level in the ladle 1 by providing a hot water level detection device and sequentially detecting a drop in the hot water level in the ladle 1. Then, the hot water level is constantly monitored, and the ladle 1 is raised by a predetermined amount based on it.

In this way, the ladle 1 is sequentially raised while discharging the molten metal from the molten metal inlet 4, and the molten metal is supplied into the injection sleeve 2.

It can be determined that the molten metal in the ladle 1 has almost completely been discharged into the injection sleeve 2 by detecting the end of the molten metal level in the ladle 1 using the detection rod 15. However, the method for detecting this is to detect when the ladle 1 has fallen to a certain value when the ladle 1 is raised based on the head-ladle rising speed curve made up of the function described above. One method is to detect when the ladle 1 has risen by a predetermined amount using a position signal transmitting device such as a rotary encoder for detecting rotation angle in the drive source part of the ladle conveyance device 12. The other method is to use a detection rod or the like for injection There is a method of detecting the upper limit of the hot water level in the sleeve 2.

In this way, once the molten metal in the ladle 1 has been discharged, the ladle 1 is continued to be moved outside the injection sleeve 2, and the hot water supply is finished.

However, when the ladle 1 is raised quickly at first and then gradually raised later, the rising speed of the ladle 1 becomes almost 0 at the end, and the hot water supply time may become longer. At that time, in order to shorten the hot water supply time as much as possible, if the detection rod 15 detects that the amount of molten metal in the ladle 1 has decreased considerably, as shown in FIG. Since the value has fallen below a certain value, the ladle 1 is raised at a slightly faster speed that hardly entrains air, so that the remaining molten metal is quickly discharged from the molten metal inlet 4.

When the supply of hot water into the injection sleeve 2 is completed, the injection sleeve 2 and the plunger tip 3 are moved to a mold section (not shown) and an injection operation is performed.

In the above embodiment, an example was shown in which molten metal is supplied into the injection sleeve 2 of a vertical die-casting machine, but this can also be used when supplying molten metal into the injection sleeve of a horizontal die-casting machine. In that case, the lower end melt spout 4 of the ladle 1, which is inserted through the hot water inlet at the top of the injection sleeve, will be located just above the bottom surface within the injection sleeve.

In this way, the present invention uses a ladle that can extend the lower part to reduce the falling distance of the molten metal.
Supplying hot water using the method described in the claims, detecting the descending state of the surface of the molten metal in the ladle,
Since the ladle is raised based on the detection state, it is also possible to use a detection rod or the like to detect when the surface of the molten metal in the injection sleeve is above the position of the supply port at the lower end of the ladle. , after its detection, it can also start raising the ladle. Then, when the ladle is raised, it becomes easy to supply the molten metal in the ladle while always gradually discharging the molten metal from the lower end of the ladle into the injection sleeve.

Furthermore, when there is a lot of molten metal in the ladle and the molten metal is discharged quickly, the ladle is raised relatively quickly, and if the amount of molten metal in the ladle gradually decreases and the molten metal discharge speed becomes slow, the ladle rises. You can also gradually reduce the speed accordingly,
Hot water can be efficiently supplied under the same conditions at all times.

Therefore, the molten metal does not swirl inside the injection sleeve during hot water supply, the molten metal rarely comes into contact with air, there is no entrainment of air, and almost no aluminum oxide is generated. Furthermore, since the molten metal is discharged quietly, there is relatively little drop in the temperature of the molten metal. By doing so, it is possible to obtain a high-quality injection product free of cavities.

Furthermore, when the ladle is raised at the speed described above, the position of the surface of the molten metal in the ladle near the end of hot water supply is detected with a detection rod, and based on that,
By making the ladle rise speed a little faster, the head between the molten metal level in the ladle and the molten metal level in the injection sleeve will become smaller, which will prevent the molten metal from taking a long time to drain, which will improve hot water supply. The required time cycle can be shortened.

In addition, when putting the molten metal in the furnace into the ladle,
After the molten metal spout at the lower end of the ladle is inserted to below the surface layer oxide film at the furnace temperature, the molten metal spout can be opened and molten metal can be poured in, so the oxide film does not enter the ladle.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a conventional method similar to the present invention, Fig. 2 is a longitudinal sectional view showing one embodiment of an apparatus for carrying out the method of the present invention, and Figs. 3 a, d, and c are FIG. 3 is an explanatory diagram showing the operation sequence in the method of the present invention. 1... Ladle, 2... Injection sleeve, 3... Plunger tip, 4... Melt spout, 5... Valve stem, 6
... Cylinder, 12 ... Ladle conveyance device.

Claims (1)

[Claims] 1. Using a ladle provided at the lower end that can open and close the molten metal inlet, pour the molten metal into the ladle and, with the molten metal inlet closed, insert the lower end of the ladle to the lower part of the injection sleeve. In this state, the molten metal in the ladle is opened and the molten metal in the injection sleeve begins to be discharged into the injection sleeve, until the upper surface of the molten metal in the injection sleeve discharged from the ladle is higher than the position of the molten metal inlet in the ladle. An automatic hot water supply method for a die-casting machine, in which a falling state of the surface of molten metal in the ladle is detected when the ladle is raised from above, and the ladle is raised based on the detected state. 2. When raising the ladle by detecting the descending state of the surface of the molten metal in the ladle, detect that the surface of the molten metal in the ladle has descended to the desired position in the ladle, and raise the ladle based on the detection signal. An automatic hot water supply method in a die-casting machine according to claim 1, wherein the automatic hot water supply method is adapted to start the process. 3 When the ladle is raised by detecting the descending state of the surface of the molten metal in the ladle, if it is detected that the molten metal in the ladle is at the end of discharge, the rising speed of the ladle is increased based on the detection signal. 3. An automatic hot water supply method in a die casting machine according to claim 1 or 2, wherein the ladle is raised by using the method described in claim 1 or 2.