JPH05220565A - Molten metal filling device - Google Patents

Abstract

(57) [Summary] [Purpose] When pouring the molten metal into the mold with the molten metal pouring device, prevent the molten metal from adhering to the bottom wall of the crucible and inject the molten metal almost completely into the mold. With the goal. [Structure] An opening 4 is provided in the center of a bottom wall 3 of a crucible 1 for containing a metal 7 to be melted. The molten metal 7b in the crucible 1 is sensed by the outflow detector 9 provided and the gas pressure injection device 10 connected to the outflow detector 9 operates to inject an inert gas into the crucible 1. Can be dropped almost completely into the mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal pouring device used for pouring a molten metal into a mold in a precision casting machine used for dentistry or the like.

[0002]

2. Description of the Related Art Conventionally, a crucible has been used as a metal melting container in a molten metal injection apparatus of this type. As the crucible, the one shown in FIG. 2 or FIG. 3 is known. That is, in the crucible 21 shown in FIG. 2, when the metal melted inside is poured into the mold, the crucible is tilted and poured from the outflow guide groove 22 formed in the upper opening edge of the crucible. Further, in the case of the crucible 23 shown in FIG. 3, the molten metal is also flown out from the upper outlet 24 by inclining it in the same manner.

Although not shown, there is also a crucible in the shape of a dish having a shallow depth. In each case, a portion corresponding to the outflow guide groove 22 or the outflow port 24 is provided, and molten metal is supplied from that portion. It is designed to be leaked. In general, the alloys used for precision casting of this type often have a small amount of about several grams to several tens of grams. Therefore, when such a small amount of metal is melted using the crucible as described above and injected into the mold, the molten metal is cooled and solidified while passing through the outflow guide groove 22 or the outlet 24 having a relatively low temperature. Occurs, and not only the problems in the casting operation, but also the proper casting temperature cannot be maintained, and in the case of a precious metal, there is a loss due to adhesion and the like. It is also possible to heat the molten metal to an appropriate temperature or higher in order to prevent early solidification as described above, but in that case, there is a problem such as roughened casting surface, occurrence of porosity, and deterioration of metal structure. ..

As a molten metal pouring device for solving these problems, the present applicant previously proposed a device as described below. That is, the crucible 25 is formed in a tapered cylindrical container shape as shown in FIG. 4, has a flange-shaped portion 27 outside the upper opening 26, and has a cylindrical side wall 28 extending below the bottom wall 29. And is divided into two parts at the center vertically into parts 25a and 25b. 30 is part 25a, 2
5b is a mating surface, and a notch 31 is formed at the upper end position from above. Also, a part 2 divided into two
5a and 25b are provided with supported portions 32a and 32b protruding downward at symmetrical positions below the flange portion 27, respectively.

As shown in FIG. 5a, the crucible 25 thus formed is provided above the high frequency coil 33 of the precision casting machine, and is provided with an air cylinder or a manual lever (not shown).
A supporting portion 32a, which is connected to a driving means such as
32b is supported, and the lower portion of the cylindrical side wall 28 is inserted into a tapered hole 36 of a crucible restraining body 35 that is separately fixed. In this state, the bottom wall 29 is located near the center of the high frequency coil 33, and the mating surface 30 is closed.

The metal melted to the pouring temperature in the crucible 25 of the pouring device having such a structure is cast into a mold (not shown) arranged under the restraining body 35 from the opening gate above the mold. Be done. In this casting operation, when the raising / lowering support body 34 is raised by the air cylinder or the manual lever from the state of FIG. 5a, the crucible 25 is also raised, and the lower portion of the cylindrical side wall 28 is pulled out from the tapered hole 36 into which it is inserted. Then, in the crucible 25, the portions 25a and 25b are respectively the supported portions 32.
Since it is supported only by a and 32b, the lower part naturally opens to both sides as shown in FIG. 5b due to the center of gravity of each of them, so that the molten metal inside falls into the mold.

[0007]

However, in the above-mentioned molten metal pouring device, the crucible rises after the melting temperature in the crucible reaches the casting temperature, and the crucible is released from the restraint body and opened.
When the molten metal is poured into the mold, if the molten metal has a high wettability, the molten metal will adhere to the cut end of the bottom wall of the crucible and not all will be poured into the mold. . Further, when an inert gas such as argon is injected under pressure to solve this problem, there is a problem that the molten metal adhering to the outside of the center of the bottom wall cutout is scattered to the outside of the mold.

[0008]

The present invention has been obtained as a result of studies for solving the above-mentioned problems in a molten metal pouring apparatus, and is formed in the shape of a container that opens upward, and its opening edge A crucible having a supported portion on the outer periphery of the crucible and an opening at the center of the bottom wall, a support for supporting the supported portion of the crucible, a high frequency induction winding on the outer periphery near the bottom wall of the crucible, A power control unit that controls the high-frequency current that is input to the high-frequency induction winding, a detector that detects the amount of molten metal flowing out from the opening in the bottom wall into the mold, and an output signal from the detector that prevents the molten metal from flowing into the crucible. A molten metal injection device comprising a gas injection device for injecting an active gas.

[0009]

The molten metal injection apparatus of the present invention is provided with an opening at the center of the bottom wall of the crucible to be used, and a detector for detecting the outflow amount of the molten metal in the crucible when it flows out from the opening. And a gas injection device for injecting an inert gas under pressure into the crucible in response to an output signal from the detector so that the molten metal can be smoothly injected into the mold.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
A detailed description will be given based on (c). In the figure, reference numeral 1 is a crucible having an opening at the upper side and formed in a cylindrical container shape, a flange-shaped portion 2 is formed outside the upper opening, and an opening portion 4 is provided at the center of a bottom wall 3. .. The crucible 1 having the above-mentioned shape is supported by the support 5 by the flange portion 2. A high frequency induction winding 6 is wound around the outer periphery of the bottom wall 3 of the crucible 1, and the winding 6 is connected to a power control unit 8 which supplies a high frequency current. 7 is a metal to be melted, which is placed inside the crucible 1. Reference numeral 9 denotes the molten metal from the opening 4 when the molten metal is cast from the opening 4 of the bottom wall 3 in the crucible 1 into a mold (not shown) arranged in advance under the apparatus. It is a detector that detects the outflow amount. As the detector 9, any one such as a photoelectric tube type, a heat ray detecting type, and a detector based on the amount of reflected light may be used. Reference numeral 10 is an inert gas pressure injection device, which is a molten metal outflow detector 9
It operates by receiving the output signal from the crucible 1 and injects a necessary amount of inert gas into the crucible 1 from the upper part of the crucible 1.

A metal to be melted as shown in FIG. 1 (a) is housed in the crucible 1 of the molten metal injecting apparatus having such a structure, and a high-frequency current is supplied from the power control unit 8 to the high-frequency induction winding 6 to supply the metal. Thaw 7 The metal 7 begins to melt from the outside due to the high-frequency current, and as shown in FIG.
However, the surface tension and the high-frequency eddy current do not cause the rotation, and the crucible 1 does not flow out of the opening 4 of the bottom wall 3 of the crucible 1. Then, when the high frequency current is cut off, the molten metal 7b cannot suppress the outflow from the opening 4 only by its surface tension,
Part of the molten metal 7b begins to flow into the mold from the opening 4 as shown in FIG. 1 (c). Thus, when the outflow of the molten metal 7b starts, the outflow amount detector 9 arranged outside the crucible 1 between the crucible 1 and the mold senses it and at the same time is connected to the outflow amount detector 9. A signal is input to the gas pressurization injection device 10 to operate the device 10, and an inert gas such as argon gas is injected into the crucible 1 from the upper part of the crucible 1, and the molten metal 7b is dropped into the mold at one time and casting is performed. It is done.

The molten metal injection apparatus of the present invention is not limited to the use of a crucible as shown in FIG.
Even if the crucible has been divided into two vertically as shown in Fig. 4 so far, it can be used by providing an opening on the bottom wall and releasing it from the crucible restraint during the inert gas injection operation. It is possible.

[0013]

As described above, the molten metal injection apparatus of the present invention is provided with an opening at the center of the bottom wall of the crucible, and a detector for sensing the amount of molten metal flowing out from this opening and the detector. By providing a gas pressurizing injection device that injects an inert gas into the crucible by a signal from, it is possible to inject the inert gas into the crucible at the same time as the molten metal flows out from the opening, so that the wettability is improved. Even if the molten metal is large, the amount of adhesion to the opening is very small, and the molten metal can be almost completely injected into the mold, and good casting can be performed. Further, since the molten metal does not scatter to the outside, the casting work in the casting chamber can be smoothly performed.

[Brief description of drawings]

FIG. 1A is a sectional view showing a molten metal injection apparatus of the present invention, and FIGS. 1B and 1C are sectional views showing a state of molten metal in the apparatus.

2A is a plan view of a conventional crucible, and FIG. 2B is a side view.

FIG. 3A is a plan view showing another conventional crucible, and FIG.
FIG. 7A is a sectional view taken along line AA of FIG.

FIG. 4A is a plan view showing still another conventional crucible,
(B) is a side view.

5 (a) and 5 (b) are vertical cross-sectional views showing a usage state of a conventional molten metal pouring device using the crucible of FIG.

[Explanation of symbols]

 1 Crucible 2 Flange-like Part 3 Bottom Wall 4 Opening 5 Support 6 High-Frequency Induction Winding 7 Metal 7a Molten Metal 7b Molten Metal 8 Power Control Section 9 Outflow Detector 10 Gas Pressurization Injection Device

Claims (1)

[Claims] 1. A crucible that is formed in a container shape that opens upward, has a supported portion on the outer periphery of its opening edge, and has an opening at the center of the bottom wall, and supports the supported portion of the crucible. A support, a high-frequency induction winding on the outer periphery near the bottom wall of the crucible, a power control unit for controlling a high-frequency current input to the high-frequency induction winding, and an outflow amount of molten metal from the opening in the bottom wall to the mold. A molten metal injection device comprising a detector for detecting and a gas injection device for injecting an inert gas into the crucible according to an output signal from the detector.