JPH0254185B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an automatic hot water supply method in a die casting machine.

[Prior art]

Conventionally, in a vertical die casting machine, when feeding molten metal such as aluminum alloy into the injection sleeve using a ladle, a ladle 1 having a shape as shown in Fig. 1 is used, and this ladle 1 is inserted into the injection sleeve in the standby position. 2, and the molten metal was dropped into the injection sleeve 2. 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;
When the molten metal was supplied into the injection sleeve 2, it swirled as shown. As a result, the molten metal is disturbed and comes into contact with air, which increases the amount of aluminum oxide, increases the amount of air involved, and lowers the temperature of the molten metal, resulting in defective injection products.

[Summary of the invention]

The present invention has been made in view of the above-mentioned points, and provides an automatic hot water supply method for a die casting machine that quietly supplies molten metal into an injection sleeve, reduces the exposure of the molten metal to air, and prevents air from being drawn in. The feature is that it uses a ladle equipped with a molten metal inlet that can be opened and closed at the lower end and a sensor that detects the surface of the molten metal in the injection sleeve at the lower part of the outer periphery above the molten metal inlet. Insert the lower end of this ladle to the lower part of the injection sleeve, and in this state, open the molten metal port and start discharging the molten metal in the ladle into the injection sleeve. When the ladle is raised after reaching a position higher than the position of the molten metal inlet, the ladle is raised while the surface of the molten metal in the injection sleeve is always located at the sensor part.

Additionally, a feature of the present invention is that in the latter half of the ladle rise, when the speed of discharging the molten metal from the ladle is slow, if the sensor does not detect the surface of the molten metal discharged into the injection sleeve after a certain period of time, a timer is activated. The ladle is raised to the outside of the injection sleeve, and the remaining molten metal in the ladle can be quickly discharged.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the automatic hot water supply method according to the present invention will be described in detail based on the drawings.

Figure 2 is a cross-sectional view of the main parts of a vertical die casting machine that employs the automatic hot water supply method according to the present invention, Figure 3 is a cross-sectional view of the ladle and injection sleeve, and Figure 4 is a cross-sectional view of the
It is a figure-line sectional view. First, an overview of the vertical die casting machine and its operation will be explained based on FIG. 2. 10 is a fixed plate, 11 is a column, 12 is a movable mold, 13 is a fixed mold, 14 is an injection unit, and 15 is an injection sleeve. , 16 is an injection plunger, 17 is an injection cylinder, and 18 is a ladle for hot water supply. The upper end of the injection plunger 16 is slidably inserted into the injection sleeve 15 to constitute a plunger tip 16a, and the lower end is connected to a piston rod 17a of an injection cylinder 17.

Between the fixed platen 10 and the fixed mold 13, there is a hole 19 in the center thereof through which the injection sleeve 15 can move up and down.
A movable polster 20 is provided, a notch 21 is provided that passes vertically from the center of the stationary platen 10 to one side end, and an injection sleeve 15 is provided within this notch 21 so as to be movable in the lateral direction. ing. The notch 21 may be in the shape of a notch groove that is open on one side of the fixed plate 10, or may be in the form of a horizontally long elongated hole that is not open on one side of the fixed plate 10.

The injection sleeve 15 is vertically removably provided at a lower position of the fixed mold 13 attached to the fixed platen 10, and the injection plunger 16 is attached to the injection sleeve 15.
In the inserted state, the injection sleeve 15 separated from the lower surface of the fixed mold 13 is moved laterally below the fixed mold 13 to a position where hot water can be supplied as shown by the chain line.

The central lower surface of the fixed mold 13 and the upper end surface of the injection sleeve 15 are formed into a dowel so that they can be easily attached and detached. The lower end of the injection sleeve 15 is integrated with a block 24 forming a cylinder 23, and is connected to a ram 2 fixed to the upper part of the injection cylinder 17.
5, the injection sleeve 15 can be moved up and down. cylinder 23 and ram 25
is provided parallel to the piston rod 17a of the injection cylinder 17, and the lower end of the block 24 is provided so as to be slidable relative to the piston rod 17a. The injection cylinder 17 is pivotably supported around a shaft 26 so as to be tiltable, is tilted by the tilting cylinder 27, and the injection position is regulated by a stopper 28.

With the injection plunger 16 inserted into the injection sleeve 15, the injection sleeve 15 is placed at position C shown by the two-dot chain line, and the ladle 18 pours the molten metal into the injection sleeve 15. Next, the tilting cylinder 27 is actuated to raise the injection unit 14 about the shaft 26 to the solid line position. Further, the cylinder 23 and the piston rod 17a are operated simultaneously to raise the injection sleeve 15 and the injection plunger 16 to the E position, and press the injection sleeve 15 against the lower surface of the fixed mold 13.

On the other hand, the mold clamping operation has been completed before this operation, and immediately after the pressing of the injection sleeve 15 is completed, pressure oil is introduced to the injection cylinder 17 to inject the molten metal. When the injection is completed and the product is cooled, the movable mold 12 is opened to take out the product. The injection plunger 16 descends in synchronization with the opening operation, and the injection sleeve 15 simultaneously descends due to the operation of the cylinder 23. When the lowering of both is completed, the tilting cylinder 27 is activated and the injection unit 14 moves to position C, completing one cycle.

In the embodiment shown in FIG. 2, after the injection sleeve 15 is lowered once, the injection unit 14 is tilted about the shaft 26 and moved laterally, but this is done by moving it horizontally instead of swinging it. It is also possible to move it in the same direction as it is, and FIG. 3 shows the state in that case.

In FIGS. 3 and 4, the ladle 18
The lower end has a slightly elongated shape so that it can be inserted into the injection sleeve 15, and has a molten metal inlet 31 whose opening and closing are controlled by a valve rod 30. A pair of sensors A and B for detecting the surface of the molten metal discharged into the injection sleeve 15 are arranged above the injection sleeve 15 at appropriate intervals in the vertical direction. On the other hand, a cylinder 3 for vertically moving the valve stem 30 is provided on the upper surface of the ladle 18.
2 is provided, and a hole 33 through which air enters and exits is bored in the outer peripheral surface of the upper end.

35 is a link that rotates in the vertical direction with its other end as a shaft 36; 37 is a chain wheel rotatably attached to the tip of the link 35 by a shaft 38;
Reference numeral 9 designates a chain that extends between the chain wheel 37 and another chain wheel 41 fixed to the frame 40 at the other end of the link 35; 42 represents a bracket that integrally connects the chain wheel 37 and the cylinder 32; By these, the ladle conveying device 45
It consists of The shaft 36 is drivingly connected to a motor 47 via a reduction gear mechanism 46.

In this case, the ladle conveyance device is not limited to that shown in FIGS. 3 and 4, and various modifications may be made, for example, it may be constructed as shown in FIG. 5. That is, this ladle conveyance device 12 includes a traveling body 51 disposed so as to be freely movable on a rail 50 disposed substantially horizontally, a rack 52 disposed long along the rail 50, and a traveling body 51 disposed so as to be freely movable on a rail 50 disposed substantially horizontally. A traveling motor 53 is mounted on a motor 51 and has a pinion 54 disposed on its output shaft 53a to mesh with the rack 52, and a rack 55 is provided in the vertical direction to connect the traveling body 51 and the cylinder 32. long connecting rod 5
6, and an output shaft 5 mounted on the traveling body 51.
A ladle raising/lowering motor 57 having a pinion 58 that meshes with the rack 55 disposed at 7a, and a traveling position detector 5 comprising, for example, a rotary encoder.
9, an elevation position detector 60, and the like.

The pair of sensors A and B are attached to the ladle 18 via a non-conductor, and as shown in FIG.
65b, and when the molten metal that is a conductor comes into contact with these electrode rods 65a and 65b, a short circuit occurs between them and the molten metal is detected, but the detection is not limited to this, and a thermocouple or the like may be used for detection Of course. Then, the ladle conveyance device 12 is driven and controlled by the detection signals of the pair of sensors A and B, and the intermittent lifting operation of the ladle 1 is performed.

Note that the sensors A and B are not limited to a pair of electrode rods, but may be a single electrode rod, and may be turned on and off between this electrode rod and the ladle 18 or between the electrode rod and the injection sleeve 15.

FIG. 7 is a circuit diagram for driving and controlling the ladle conveyance device 45, in which sensor A is disposed at a lower position than sensor B on the outer peripheral surface of the lower end of the ladle 18, and when the molten metal stops coming into contact with it, it sends out a signal, and the sensor B is configured to send out a signal when it comes into contact with molten metal.
70 is a flip-flop circuit; when a signal is input to a set terminal S, an output is output from an output terminal Q; when a signal is input to a reset terminal R, no output is output. Output terminal Q
The output of SET terminal S remains in the same state even if the input to the set terminal S disappears. Similarly, even if there is no input to the reset terminal R, the state of no output from the output terminal Q is maintained. 71, 72 are and gates, 73
is a timer, and the time of this timer 73 is set to be longer (for example, 1 to 2 seconds) than the normal time it takes for the surface of the molten metal discharged into the injection sleeve 15 to reach the sensor B from the sensor A. 74 outputs to the motor 47 of the ladle conveyance device 45;
The flip-flop circuit is configured to operate the motor 47 when an output is output from its output terminal Q, and to stop the motor 47 when the output disappears.

Next, a hot water supply operation with such a configuration will be explained. First, the lower part of the ladle 18 is placed in the molten metal in a furnace (not shown), the molten metal inlet 31 is positioned below the surface oxide film of the molten metal, and the cylinder 32 is actuated to raise the valve rod 30 to open the molten metal inlet. A desired amount of molten metal is poured into the ladle 18 from 31. in this case,
The amount of hot water supplied is determined by the vertical position of the ladle 18 with respect to the surface of the molten metal in the furnace. Fixing the ladle 18 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 18 or the like.

Next, when a desired amount of molten metal is pumped into the ladle 18, the cylinder 32 is driven to lower the valve rod 33 to close the molten metal inlet 30, and the ladle conveying device 45 is activated to move the ladle 18 to the injection position at the standby position. sleeve 1
The lower part of the ladle 18 is further inserted into the injection sleeve 15 as shown in FIG. 3, and the melt spout 30 is brought close to the upper surface of the plunger tip 16a. At this time, the distance between the molten metal spout 31 at the lower end of the ladle 18 and the plunger tip 16a varies depending on the height of the molten metal in the ladle 18 and the area of the molten metal spout 31, but may be 5 to 10 mm, for example. The distance is relatively small enough to prevent gas from being drawn into the molten metal when it flows out.

In this state, the cylinder 32 is driven and the valve stem 30
is raised to open the molten metal spout 31 and begin to discharge the molten metal in the ladle 18 into the injection sleeve 15. This state is shown in FIG. 8a. If the ladle 18 is left stationary, the molten metal is sequentially discharged from the molten metal spout 31, and accordingly, the molten metal in the injection sleeve 15 is gradually pushed up by new molten metal from below without stirring the surface layer. The upper surface of the injection sleeve 15 will soon reach the molten metal spout 31 at the lower end of the ladle 18.
be higher than the position of And injection sleeve 1
When the upper surface of the molten metal in 5 rises further than the position of the molten metal inlet 31, for example, rises by about 5 to 10 mm, sensor A
touch. Then, sensor A stops sending the control signal to AND gate 71 shown in FIG.

The sensor A continues to send out the control signal until the molten metal in the injection sleeve 15 comes into contact with it, but since the flip-flop circuit 70 was first reset by the reset signal from the reset terminal R, no output signal is output from the flip-flop circuit 70. It is not sent to AND gate 71, and AND gate 71 never sends an output. Therefore, timer 73
does not operate at the start of dispensing molten metal, but starts operating when sensor B first detects molten metal in the injection sleeve 15 and then sensor A detects molten metal. Injection sleeve 1
When the molten metal in 5 rises further than the sensor A position and touches sensor B, sensor B sends a control signal to the flip-flop circuit 70 and its output terminal Q.
Sends output from . Flip-flop circuit 7
The signal output from output terminal Q of 0 is AND gate 7
Open 1,72. Therefore, and gate 72
The output from the flip-flop circuit 74 is input to the set terminal S of the flip-flop circuit 74, and a signal is sent out from the output terminal Q. This signal is sent to the motor 47 to drive the motor 47 and quickly raise the ladle transport device 45. As the ladle conveying device 45 rises, the ladle 18 also rises as shown in FIG. No more contact with A. At this time, sensor A again sends a control signal to AND gate 71 .
The AND gate 71 has a flip-flop circuit 70
When the signal from sensor A is input, AND gate 71 is opened.
is input to the reset terminal R of the timer 73 and flip-flop circuit 74. As a result, flip-flop circuit 74 no longer sends out an output, causing motor 47 to stop. Therefore, the ladle transport device 45 is stopped and the ladle 18 is stopped at that position. Even if the ladle 18 stops, the molten metal is constantly discharged from the molten metal inlet 31 of the ladle 18 into the injection sleeve 15, so the surface of the molten metal in the injection sleeve 15 continues to rise, touches the sensor A, and then Touch B. Therefore, as described above, the ladle conveying device 45 operates again to raise the ladle 18 and then stops. In this way, the ladle 18 is intermittently raised so that the surface of the molten metal discharged into the injection sleeve 15 is always located at the sensor A and B sections, and the molten metal in the ladle 18 is transferred to the injection sleeve 15.
It is expelled inside.

Here, the timer 73 starts operating according to the signal from the AND gate 71 and counts the time, but the time it takes for the molten metal to reach the sensor B position from the sensor A position is extremely short, and the time set in the timer 73 is Therefore, the timer 73 times up and the flip-flop circuit 7
No signal is sent to the set terminal S of No.4.
As the molten metal is discharged from the ladle 18, the height difference (head) between the molten metal surface in the ladle 18 and the molten metal surface in the injection sleeve 15 gradually becomes smaller, so that the molten metal discharged from the molten metal spout 31 is discharged. The speed also gradually slows down. Therefore, the time for the molten metal in the injection sleeve 15 to reach the sensor B from the sensor A is delayed, and the height at which the ladle 18 rises changes each time and gradually becomes smaller.

In the second half of the ladle rising, the head is almost gone and the speed of the molten metal flowing out from the molten metal spout 31 becomes extremely slow, so it takes a long time for the molten metal in the injection sleeve 15 to touch sensor B after it touches sensor A. become. If this time becomes longer than the time set in the timer 73, the timer 7
3 sends a signal to the set terminal S of the flip-flop circuit 74 assuming that the discharge of the molten metal from the ladle 18 is almost completed. For this purpose, the flip-flop circuit 74 sends a signal to operate the motor 47, which operates the ladle conveying device 45 to raise the ladle 18 above the injection sleeve 15 and stop it. At this time, the remaining molten metal in the ladle 18 is quickly discharged from the molten metal inlet 31, and the supply of the molten metal to the injection sleeve 15 is completed. FIG. 8c shows this finished state.

In addition, the ladle rising speed during the period from the start of molten metal discharge to the latter half of the ladle rise is as follows:
Area of molten metal spout 31, amount of molten metal, sensor A and sensor B
It is changed as appropriate depending on the interval etc. Furthermore, by increasing the rate of rise of the ladle 18 near the end of hot water supply, the remaining molten metal can be discharged quickly and the hot water supply time can be shortened accordingly. At this time, since the head is small, the molten metal hardly entrains air. When the supply of hot water into the injection sleeve 15 is completed, the injection unit 14 is moved to the injection position shown by the solid line in FIG. 2 and performs the injection operation, as described above.

Although the above embodiment shows an example in which molten metal is supplied into the injection sleeve 15 of a vertical die-casting machine, the present invention is not limited to this, and can also be applied to the case where molten metal is supplied into the injection sleeve of a horizontal die-casting machine. In that case, the lower end melting port 31 of the ladle 18 inserted from the top melting port of the injection sleeve,
It may be located just above the inner bottom surface within the injection sleeve.

Furthermore, although the above embodiment uses a pair of sensors A and B, it is also possible to use one sensor. In that case, as shown in FIG. The control circuit can be designed using the following information.

In this case, since there is only one sensor, timer 7
Another timer 80 having a set time shorter than the set time of 3 will be incorporated. Then, each time the molten metal touches the sensor B, the ladle conveying device 45 is activated and stopped for a certain period of time set in the timer 80, and the ladle 18 is intermittently raised by a certain distance regardless of the rising speed of the molten metal. Therefore, when the time it takes for sensor B to detect molten metal near the end of hot water supply becomes longer than the time set in timer 73, timer 73 times up and sends a signal to set terminal S of flip-flop circuit 70. Then, the motor 47 is operated to draw the ladle 18 out of the injection sleeve 15.

Further, the sensors A and B are not limited to those directly fixed to the lower part of the outer circumferential surface of the ladle 18, but may be arranged separately.

Further, in the above embodiment, the ladle conveying device 45 is raised by the motor 47, but it may be raised by a hydraulic cylinder.

〔Effect of the invention〕

As described above, according to the automatic hot water supply method for a die casting machine according to the present invention, a sensor for detecting the surface of the molten metal discharged into the injection sleeve is disposed at the lower part of the outer periphery of the ladle, and a control signal from this sensor is used. Since the molten metal in the ladle is discharged while the ladle is raised intermittently, the molten metal does not swirl inside the injection sleeve during hot water supply, and there is little exposure of the molten metal to the air. There is no entrainment of aluminum, 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. Therefore, it is possible to obtain a high quality injection product free of cavities.

In addition, when there is little molten metal left in the ladle, a timer works to raise the ladle to the outside of the injection sleeve independently of the sensor's level detection, so it takes a long time to drain the molten metal near the end of hot water supply. You can prevent this from happening,
The hot water supply time can be shortened to some extent.

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 a diagram showing a conventional hot water supply method, FIG. 2 is a vertical sectional view showing an embodiment of a vertical die casting machine for implementing the automatic hot water supply method according to the present invention, and FIG.
The figure is a sectional view of the ladle and injection sleeve, FIG. 4 is a sectional view taken along the line of FIG. 3, FIG. 5 is a sectional view showing another embodiment of the ladle conveying device, FIG. The figure is a circuit diagram for driving and controlling the ladle conveyance device, FIGS.
FIG. 2 is a circuit diagram when one is used. 15... Injection sleeve, 16a... Plunger tip, 18... Ladle, 30... Valve stem, 31...
...Melting spout, 32... Cylinder, 45... Ladle conveyance device, 73, 80... Timer, A, B... Sensor.

Claims (1)

[Claims] 1. Using a ladle equipped with a molten metal spout that can be opened and closed at the lower end and a sensor that detects the surface of the molten metal in the injection sleeve at the lower part of the outer periphery above the molten metal spout, the molten metal is poured into the ladle. With the molten metal spout closed, insert the lower end of this ladle all the way down into the injection sleeve. In this state, open the molten metal spout and begin to discharge the molten metal in the ladle into the injection sleeve. When raising the ladle after the upper surface of the molten metal in the injection sleeve is higher than the position of the molten metal inlet of the ladle, raise the ladle while ensuring that the surface of the molten metal discharged into the injection sleeve is always located at the sensor part. An automatic hot water supply method for a rising die casting machine. 2 Using a ladle equipped with a molten metal spout that can be opened and closed at the lower end and a sensor that detects the surface of the molten metal in the injection sleeve at the lower part of the outer periphery above the molten metal spout, the molten metal was poured into this ladle and the molten metal spout was closed. In this state, insert the lower end of this ladle to the bottom of the injection sleeve, and in this state, open the molten metal port and start discharging the molten metal in the ladle into the injection sleeve. When the ladle is raised after its upper surface is higher than the position of the molten metal inlet of the ladle, the ladle is raised so that the surface of the molten metal discharged into the injection sleeve is always located at the sensor part, and the ladle In the second half of the rise, when the sensor does not detect the surface of the molten metal discharged into the injection sleeve after a certain period of time, a timer is activated to raise the ladle.