JPH0757415B2 - Automatic hot water supply method for die casting machine - Google Patents

Description

The present invention relates to a hot water supply method for pouring molten metal into a vertical sleeve in a vertical die casting machine.

[Prior Art] Die casting machines are classified into a vertical mold and a horizontal mold according to the mold clamping direction, and are classified into a vertical mold and a horizontal mold according to the casting direction. Of these, the horizontal vertical vertical casting die casting machine is configured as follows.

That is, a movable plate is supported on four tie rods that connect a pair of fixed plates standing upright on the machine base so as to move forward and backward with respect to one fixed plate. A movable mold and a fixed mold are mounted on the fixed plate and the fixed plate, respectively. A cavity is formed at the joint between the movable mold and the fixed mold, which is moved together with the movable plate and clamped by the mold clamping cylinder on the other fixed plate side, and the fixed mold communicates with the cavity. The sleeve is fitted so as to open downward. Below the fixed mold, an injection device is supported in an upright and tiltable manner. This injection device includes an injection cylinder fixed to an injection frame,
The plunger is connected to the piston rod, and the plunger tip is fitted into the inner hole of the vertically movable injection sleeve on the injection frame side.

With this configuration, after the mold is clamped, when the entire injection device is tilted and molten metal is started into the injection sleeve by the hot water supply device, the plunger tip is raised to the highest position and then hot water supply is started. When the injection sleeve is lowered and reaches the lowest position as the hot water supply progresses, the thermocouple constantly detects the end of the surface of the molten metal discharged into the injection sleeve, so that the position of the upper surface of the molten metal in the injection sleeve is first detected. It was possible to keep it almost constant from the end to the end, and the pouring of the molten metal was performed extremely quietly with the head of the molten metal always becoming the minimum.

Thus, when the injection device is then placed upright and the injection sleeve is joined to the fixed sleeve, and the plunger tip of the injection cylinder is raised, the molten metal is injected into the cavity through the fixed sleeve, so that the molten metal is solidified. A cast product is obtained.

[Problems to be Solved by the Invention] However, the end of the surface of the molten metal supplied from the automatic water heater into the injection sleeve is constantly detected by a thermocouple, and the detected temperature is fed back to the molten metal to be supplied into the injection sleeve. When trying to control the amount, there was a problem that it was difficult to perform fine follow-up control due to the time delay from detecting the molten metal temperature with the thermocouple until opening and closing the open / close rod of the automatic water heater. .

[Means for Solving the Problem] In order to solve such a problem, in the present invention, a lower end molten metal discharge port of a hot water supply sleeve provided in a downward direction of a bottom portion of an automatic hot water supply device is lowered in an injection sleeve. With the injection sleeve and the plunger tip positioned so that they are located just above the upper surface of the plunger tip, the hot water supply from the lower end of the hot water supply sleeve to the inside of the injection sleeve is started, and as the hot water supply progresses. When hot water is supplied by lowering the injection sleeve and the plunger tip together, the thermocouple device is installed so as to be separated from the outer wall surface of the hot water supply sleeve and shorter than the sleeve tip, and the interface of the molten metal is the thermocouple. When a constant temperature gradient α is reached near the tip of the device, the amount of hot water supplied from the lower end of the hot water supply sleeve to the injection sleeve is reduced, and the melt interface is reduced. When it is at a constant temperature gradient β in contact with the tip of the thermocouple device was to stop the hot water to the injection sleeve from the lower end portion of the sleeve of the hot water supply.

[Operation] The molten metal is stored in the greenhouse and the hot water supply chamber inside the furnace of the automatic water heater.
When the sleeve for hot water supply is inserted into the injection sleeve of the injection device moved to the lower end of the furnace to open the open / close rod,
The molten metal in the furnace is discharged into the injection sleeve.

Therefore, in order to keep the upper surface position of the molten metal in the injection sleeve constant from the beginning to the end, when the injection sleeve and the plunger tip are simultaneously lowered, if the molten metal interface approaches the detection end of the thermocouple tip and the temperature gradient changes. When the molten metal is brought into direct contact with the detection end and the temperature gradient changes abruptly, a command to stop the molten metal supply is issued.

However, although the hot water supply was stopped, the injection sleeve and plunger tip continued to descend continuously and integrally at a constant speed, so the thermocouple and molten metal interface were separated by this descending distance, and the control system Hot water supply to the injection sleeve is started again via. Under these conditions, at the end, when the limit switch is reached and the limit switch is turned off, the end position of the surface of the molten metal is detected, the hot water supply opening / closing rod attached to the tip of the furnace is closed, and hot water supply is stopped. By issuing such a command, a fixed amount of hot water is supplied into the injection sleeve.

[Embodiment] FIGS. 1 to 6 show one embodiment according to the present invention. FIG. 1 is a vertical sectional view of an automatic water heater, and FIG. 2 is a case of supplying water from an automatic water heater into an injection sleeve. The operation sequence of the injection sleeve and the plunger tip is shown in FIG. 2 (a) immediately after hot water supply is started, FIG. 2 (b) is during hot water supply, and FIG. 2 (c) is at the end of hot water supply. FIG. 3 is an overall view showing a preferred example for carrying out the present invention, FIG. 4 is a schematic side view of a part of the whole shown to explain the operation of the automatic water heater, and FIG. 6 shows a temperature curve detected by the thermocouple according to the change of the molten metal level, and FIG. 6 is a schematic diagram of the control system used for implementing the present invention.

First, the automatic water heater according to the present invention will be described.
In FIG. 1, the furnace 2 of the automatic water heater 1 is formed in a generally rectangular box shape, and the heater 3 is housed in the outer wall of the double structure. Inside the furnace 2, a partition wall 4 separates a greenhouse 5 and a hot water supply chamber 6, and a central part or a lower part of the partition 4 has a filter 7 for communicating both chambers 5 and 6.
Is provided. The molten metal 8 heated by the heater 3 is stored in the greenhouse 5, and the molten metal 8 from which hard spots and oxides have been removed by the filter 7 is also kept warm in the hot water supply chamber 6 as well. It is stored with the same hot water level as room 5. The mesh size of the filter 7 is set so as to delay the passage of the molten metal 8. Since one injection shot is usually 20 seconds or more, the amount of the molten metal 8 passing is, for example, 1 Kg /
Set to 20 seconds. Reference numeral 9 is a pouring port opened at the upper end of the furnace 2.

The furnace 2 formed in this way has a base 10 as shown in FIG.
And an air cylinder 11 are tiltably supported. That is, at the rear end of the base 10, bearings 12 are integrally formed on both left and right sides of the drawing, which are the front side and the paper back side, and the shafts 13 are rotatably attached to the left and right bearings 12. It is supported, and a pair of left and right support arms 14 are fixed to the shaft 13.
The front end of the furnace 2 is pivotally attached to the free end of the support arm 14 by means of pins 15 at both left and right ends, and the table 10 is provided at the center of the lower end of the furnace 2 in the longitudinal and width directions. The working end of the piston rod 16 of the air cylinder 11 pivotally attached to the side is pivotally attached. By doing this, the air cylinder 11
When the piston rod 16 is moved upward from the position shown in the drawing, the furnace 2 is rotated around the pin 15 with the supporting arm 14 stationary, and the front end is lowered as shown by the chain line 2A in the figure. It is configured to tilt. Further, when the piston rod 16 of the air cylinder 11 is retracted from the illustrated position in the descending direction, the furnace 2 rotates about the shaft 13 while swinging the support arm 14, and as shown by a chain line 2B in the figure, The rear end is tilted in the descending direction. In addition, when the furnace 2 tilts from the solid line position to the chain line 2A position, the molten metal surface of the molten metal 8 is filtered by the filter 7 as shown by reference numeral 8A in the figure.
The surface is flush with the lower end of the room, and the amount of residual hot water in the greenhouse 5 is minimal. When the furnace 2 is tilted from the solid line position to the chain line 2B position, the molten metal surface of the molten metal 8 is filtered by the filter 7 as shown by reference numeral 8B in the figure.
Hot water supply 8 does not remain in hot water supply chamber 6 on the same plane as the lower end of.

An air cylinder 27 is fixed to the upper surface of the front end of the furnace 2, and a piston rod 18 thereof is suspended in the hot water supply chamber 6, and an opening / closing rod 19 formed of, for example, ceramic or the like is provided at its working end. They are connected concentrically. On the other hand, the hole formed at the lower end of the hot water supply chamber 6 has a closing ring 20 and a sleeve.
21 and 21 are fitted and the sleeve 21 has an opening / closing rod 19
Is provided with a valve seat 21a which is opened and closed by a valve portion at the tip thereof when the valve seat 21a moves forward and backward. In addition, the closing ring 20 should have an open / close rod 19
A valve seat 20a is provided which is closed by the upper end valve portion when the valve is broken.

Reference numeral 22 is an injection sleeve for vertical injection on the side of the injection device that is movable in the horizontal direction and the vertical direction, and the sleeve 21 is inserted into its inner hole by moving upward and moving upward. The open / close rod 19 opens the valve seat 21a so that the molten metal 8 in the hot water supply chamber 6 is supplied into the injection sleeve 22.

Next, regarding the temperature detection of the molten metal 8 and the control of the molten metal amount,
A thermocouple device 24 for detecting the temperature of the molten metal 8 supplied into the injection sleeve 22, and further, the detected temperature is once processed to transmit a command to control the amount of molten metal supplied to the injection sleeve 22. The hot water supply control device 80 is used.

As shown in FIG. 6, the thermocouple device 24 uses a thermocouple 24a for detecting the temperature of the molten metal 8, a silicon nitride thermocouple protection tube 24b and a thermocouple 24a for protecting the thermocouple 24a. It consists of a cold junction compensation 24c for correcting all temperatures to a constant reference temperature (° C) at the cold junction temperature. Further, hot water supply control device 80 includes an amplifier 81, an A / D converter 82, an arithmetic processing device 83 and a D / A converter 84.

First, the thermocouple 24a for detecting the temperature of the molten metal 8 is attached to the sleeve 21.
The sleeve 21 is disposed slightly apart from the side wall and shorter than the tip of the sleeve 21 by, for example, 5 to 10 mm. Immediately before the interface of the molten metal 8 comes into contact with the thermocouple 24a, the region where the gas temperature between the molten metal 8 and the thermocouple 24a is heated as the molten metal level rises and the temperature gradient α changes is the II region, and further, A region where the temperature gradient β changes because the high temperature molten metal 8 contacts the tip of the thermocouple 24a is referred to as a region III. In order to detect the temperature between the II and III regions and control the hot water supply amount, the thermocouple 24a
When the temperature detected in step II is in the II range, it is sent from the thermocouple device 24 to the hot water supply control device 80, the air cylinder 27 as the controlled object is operated, and the open / close rod 19 is lowered to the injection sleeve 22. When the amount of hot water supplied is reduced and when the temperature detected by the thermocouple 24a is in region III, a command signal is issued to the air cylinder 27 to lower the open / close rod 19 to stop hot water supply to the injection sleeve 22. It has become.

On the other hand, a vertical die casting machine injection device having an injection sleeve 22 will be described with reference to FIG.

A ball holder 38 is fixed to the side surface of the cylindrical body of the injection device 32 via a reinforcing member, and a ball groove for holding a ball (not shown) is formed on the inner surface of the ball holder 38. With this configuration, when driven by the drive device, the injection device 32 moves on the rail 34 mounted on the support plate 33 while rolling the ball in the ball groove.

A cylindrical injection sleeve 22 is concentrically fixed with a fixed sleeve (not shown) for vertically injecting a die provided above the injection sleeve 22.

By feeding oil from below a not-shown lift cylinder, the injection sleeve 22 ascends together with the lift shaft, and its upper end is joined to the lower end of the fixed sleeve.

The operation of the vertical die casting machine injection device and the automatic hot water supply device configured as described above will be described with reference to FIG.

First, when the molten metal 8 supplied from the pouring port 9 is stored in the warming chamber 5 with the furnace 2 of the automatic water heater 1 in the horizontal position shown by the solid line in FIG. 2, the molten metal 8 passes through the filter 7 and the hot water supply chamber. 6
Also, it is stored on the same hot water level as in the greenhouse 5.

On the other hand, for injection by the vertical die casting machine injection device, the plunger tip 23 is moved to a desired position. In this way, a volume commensurate with the amount of molten metal that can be filled in the mold cavity is secured, and then the release agent is applied to the molten metal contact surface.

Under this condition, if the drive unit pushes the entire injection device 32 in the direction of the paper spine in the figure, the injection device 32 moves the balls in the ball holder 38 to the pouring position on the rail 34 while rolling the balls in the ball grooves. Then, the injection sleeve 22 is set so that the tip of the injection sleeve 22 abuts on the hot water supply port at the bottom of the hot water supply chamber 6 of the automatic hot water supply device 1.

Next, when the air cylinder 27 is operated to raise the open / close rod 19, the molten metal 8 is supplied into the injection sleeve 22.

When starting this hot water supply,
Hot water supply is started while the plunger tip 23 is lowered to the lowest position as shown in FIG. 2C, and as the hot water supply progresses, the injection sleeve 22 and the plunger 22 as shown in FIG. 2A to FIG. 2B. Lower tip 23 at the same time,
The hot water supply should be completed at the lowest position in Fig. 2 (c).

In this case, referring to FIGS. 5 and 6, the injection sleeve
22 and plunger tip 23 are integrated, for example, 5-10 mm / s
A method of controlling the amount of hot water supplied when the molten metal 8 is supplied from the automatic hot water supply device 1 to the injection sleeve 22 while descending at a constant rate of ec will be described. Here, the reason why the injection sleeve 22 and the plunger tip 23 are integrally lowered is that the injection sleeve 22 is inserted into the hot water supply port under the hot water supply chamber 6 of the automatic hot water supply device 1.
After the tip ends of the contact points, the timer (not shown) is used.

In FIG. 5, the symbol C indicates the position where the molten metal level in the injection sleeve 22 contacts the tip of the thermocouple 24a. Symbol α
Is a temperature gradient having a value of, for example, 3 to 8 ° C./mm in this embodiment when the interface of the molten metal comes closer to the tip of the thermocouple 24a, which is indicated by the II region. The symbol β indicates that when the interface of the molten metal comes into contact with the tip of the thermocouple 24a, for example, 2
It is a temperature gradient with a value of 0-40 ° C./mm, which is shown in the III region. In this case, the temperature gradient is a condition that the injection sleeve 22 and the plunger tip 23 are descending at a constant speed.

In the state of the I region, the molten metal level is low at the start of supplying the molten metal 8 into the injection sleeve 22, the interface between the molten metal 8 and the tip of the thermocouple 24a are separated, and the set temperature gradient and the measured temperature gradient are compared. However, there is no difference. Therefore, the amount of hot water supplied to the injection sleeve 22 is not controlled, and the molten metal level is in the process of rising.

If such a state continues, the melt level will gradually rise,
The surface of the molten metal 8 and the tip of the thermocouple 24a gradually approached II
Reach the area. Here, since the actually measured temperature gradient becomes high, a difference occurs when the set temperature gradient and the actually measured temperature gradient are compared, and the automatic water heater 1 transfers to the injection sleeve 22 via the control system as shown in FIG. Operates to reduce hot water supply.

That is, the temperature detected by the thermocouple 24a is taken out as an electric quantity, the amplifier 81 converts the amplified value proportional to the electric quantity by the A / D converter 82 into the analog value, and then the arithmetic processing unit 83. The output signal as an analog value is controlled by the D / A converter 84, and the introduction amount of the compressed air supplied to the air cylinder 17 is controlled by the D / A converter 84. 19 is lowered to adjust the distance between the valve seat 21a and the opening / closing rod 19 to reduce the amount of molten metal flowing out from the sleeve 21.

Further, in the III region, the relative rising speed of the injection sleeve 22 and the plunger tip 23 and the rising speed of the molten metal level in the injection sleeve 22 are relatively high, and the rising speed of the molten metal becomes large. At the point C where C contacts the tip of the thermocouple 24a, the thermocouple 24a detects the molten metal temperature. At this time, in the comparison between the set temperature gradient and the actually measured temperature gradient, a difference is further generated than in the II region, so the introduction amount of the compressed air supplied to the air cylinder 27 is controlled through the control system described above, and the opening / closing rod 19 is opened. By lowering the gap between the valve seat 21a and the opening / closing rod 19 to eliminate the gap, hot water supply from the sleeve 21 to the injection sleeve 22 is stopped.

Although such hot water supply is stopped, the injection sleeve 22 and the plunger tip 23 continue to descend continuously and integrally at a constant speed. Therefore, the interface between the thermocouple 24a and the molten metal 8 is separated by this descending distance. This means that the temperature detected by the thermocouple 24a indicates the temperature gradient in the rear region of the II region or I region described above, so that a little more molten metal 8 can be supplied to the injection sleeve 22 via the control system. Done. This allows the injection sleeve 22 and the plunger tip to
The rising speed of the molten metal 8 is higher than the integrally descending speed of 23, and the molten metal 8 returns to the position having the temperature gradient α in the II region again.

In this way, by keeping the temperature gradient detected by the thermocouple 24a in the region II, the head of the molten metal 8 is always minimized and the molten metal is supplied very quietly. It can be prevented from being mixed.

In this way, the final end of the lowest position is opened by opening a limit switch (not shown) attached to one end of a piston (not shown), so that the lowering of the injection sleeve 22 and the plunger tip 23 is stopped, and at the same time, the air cylinder 27 is activated. Then, the opening / closing rod 19 descends, the valve seat 21a closes, and hot water supply is stopped.

After supplying hot water in this way, as shown in FIG.
The injection device 32 is moved horizontally so as to return to a position below the injection position.

Next, when oil is fed to the lifting cylinder, the injection sleeve 22 integrated with the lifting shaft rises and is joined to the fixed sleeve of the mold, after which the plunger tip 23 rises and the molten metal 8 in the injection sleeve 22 becomes It is injected into the cavity of the mold through the fixed sleeve.

After the injection operation, after cooling and solidifying the injection product, open the mold,
Retract the plunger tip 23. Further, after that, the lifting shaft and the injection sleeve 22 are also retracted at the same time.

Thus, finally move the injection device 32 to the lubrication position,
One cycle ends.

In the present embodiment, the vertical movement of the plunger tip 23 and the vertical movement of the injection sleeve 22 were performed using a hydraulic mechanism, but the present invention is not limited to this, and a vertical drive device using a ball screw mechanism is used. Similar results can be obtained by using.

[Effects of the Invention] As is clear from the above description, according to the present invention, when pouring the molten metal into the injection sleeve of the vertical die casting machine, the hot water supply is started from the automatic water heater with the plunger tip lowered. , When hot water is supplied while simultaneously lowering the injection sleeve and the plunger tip as the hot water is supplied, the interface of the molten metal should be in the II region having a constant temperature gradient α under the condition that it is closer to the tip of the thermocouple device. Since the amount of hot water supplied is controlled, the molten metal head is always minimized and the hot water is supplied very quietly, so that the poured molten metal is not agitated, the generation of molten slag is reduced, and the product quality is significantly improved. To do.

[Brief description of drawings]

1 to 6 show one embodiment according to the present invention. FIG. 1 is a longitudinal sectional view of an automatic water heater, and FIG. 2 is an injection sleeve and a plunger when water is supplied from the automatic water heater into the injection sleeve. The operation sequence of the chips is shown in FIG. 2 (a) immediately after the hot water supply starts, FIG. 2 (b) during the hot water supply, and FIG. 2 (c) at the end of the hot water supply. FIG. 3 is an overall view showing a preferred example for carrying out the present invention, FIG. 4 is a schematic side view of a part of the whole shown to explain the operation of the automatic water heater, and FIG. 6 shows a temperature curve detected by the thermocouple according to the change of the molten metal level, and FIG. 6 is a schematic diagram of the control system used for implementing the present invention. 1 ... Automatic water heater, 2 ... Furnace, 5 ... Greenhouse, 6 ... Hot water supply room, 7 ... Filter, 8 ... Molten metal, 17 ... Plunger, 19 ... Opening / closing rod, 22 ... Injection sleeve , 23 ...... Plunger tip, 24 ...... Thermocouple device, 27 ...... Air cylinder, 32 ...... Injection device.

Claims (1)

[Claims] 1. An injection sleeve so that a lower end molten metal outlet of a hot water supply sleeve provided downwardly of a bottom portion of an automatic hot water supply apparatus is located immediately above an upper surface of a plunger tip in a lower position in the injection sleeve. With the plunger tip positioned, start hot water supply from the lower end of the hot water supply sleeve into the injection sleeve, and as the hot water supply progresses, the injection sleeve and plunger tip are lowered together to provide hot water supply. In a thermocouple device arranged apart from the outer wall surface of the sleeve and shorter than the sleeve tip portion, when the interface of the molten metal approaches the tip portion of the thermocouple device and becomes a constant temperature gradient α, The amount of hot water supplied from the lower end of the hot water supply sleeve to the injection sleeve is reduced, and the interface of the molten metal comes into contact with the tip of the thermocouple device to obtain a constant temperature gradient β.
In this case, the hot water supply from the lower end of the hot water supply sleeve to the injection sleeve is stopped.