JPH07185778A - Device for pouring molten metal - Google Patents

Abstract

PURPOSE:To obtain casting of small capacity of molten metal without cooling by dividing a crucible opened at the upper part into two in the vertical direction, supporting the crucible with a flange at the outside of an opening edge part and passing to the inside from both sides to open the bottom wall. CONSTITUTION:Metal to be melted is charged into the crucible 10 and a melting chamber and a casting chamber are integrally sealed and evacuated to reduce the pressure in these chambers. After reducing the pressure, inert gas is poured and high frequency electric power is impressed to a high frequency induction coil 19 to melt the metal. A crucible openable arm 30 is pushed inward with a cylinder to release the abutment of a restricting part 30a and a crucible openable body 21. Therefore, the crucible openable body 21 is pushed inward with a spring 28 and a flange fixed opening part 23 pushes the flange 11 of the crucible 10 inward and the bottom wall 13 is quickly opened by making the bottom of a notching part 14 the support point. Then, the molten metal is dropped into a sprue 2a in a mold as one block in an instant.

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 in a molten metal injection apparatus of this type, and a crucible as shown in FIG. 3 is known. In the crucible 51 shown in the figure, when the metal melted in the crucible is poured into the mold, it is poured from the outflow guide groove 52 formed in the upper opening edge of the crucible which tilts the crucible. In general, alloys used in this type of precision casting 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 solidification starts when passing through the position of the outflow guide groove 52 having a relatively low temperature. Not only problems in the casting operation, but also the inability to maintain an appropriate casting temperature, and in the case of precious metals, there are losses due to adhesion and the like. It is conceivable to heat the molten metal to an appropriate temperature or higher in order to prevent early solidification, but in that case, problems such as roughened casting surface, generation of porosity and deterioration of metal structure occur separately.

Therefore, the present applicant has proposed a molten metal injection apparatus as shown in FIG. 4 in Japanese Patent Publication No. 59-7540. That is, the crucible 60 has a container-like shape with an upper opening, and is wholly divided vertically. Each divided part 60
The supported portions 68a, 6 are provided at positions outside the edges of the openings of a, 60b.
8b is provided. As shown in FIG. 4A, the crucible 60 is supported by a support body 70, and the lower part is restrained by a restraint body 71. At this time, the high frequency coil 6
High-frequency power supplied to 9 and metal 7 housed in crucible
Thaw 5 Then, as shown in FIG.
When 0 is moved upward or the restraint body 71 is moved downward, the restraint is released. Each part 6 divided when the constraint is released
0a and 60b open the lower part to the outside by their own weight. As a result, the metal 75 melted in the crucible falls downward and is cast.

[0004]

[Problems to be Solved by the Invention] However, Japanese Patent Publication No. 59-
In the molten metal injecting apparatus of No. 7540, the metal to be melted in the crucible 60 is arranged almost in the center of the high-frequency coil 69, so that the legs 64 at the bottom of the crucible 60 need to be long. Therefore, the molten metal was cooled and solidified during 100 to 200 msee before falling into the gate of the mold, and complete casting was not possible. In addition, since this crucible opens outward due to its own weight, the molten metal falls in a shape that gradually expands, so the part that first reached the sprue is cooled in the runner of the mold and solidified by the time when the final part reached the argon. Even when pressurized with an inert gas such as gas, the tip of the mold may not be completely cast. Furthermore, when pressurizing with an inert gas, the above-mentioned melting part may be scattered. In addition, since the bottom wall 65 of the crucible 60 is thicker than the side wall, the crucible is liable to be thermally distorted due to the melting of the metal, and is easily damaged. For this reason, it is necessary to raise the melting temperature, and there is a problem that porosity easily occurs.

[0005]

A crucible provided with a flange on the outside of the edge of the opening of each of the divided parts, which is formed into a container shape and is vertically divided as a whole. By the crucible support that supports the flange, the crucible opening and closing body that presses the upper part of the flange of the crucible and fixes and releases the crucible inward from both sides, and the fixing and releasing means that unwinds the crucible opening and closing body. Configured.

Further, a crucible opening / closing arm having a wide restraining portion for constantly engaging the fixing / releasing means with the crucible opening / closing body and a narrow releasing portion outside the crucible opening / closing arm, and a pressing member for constantly pressing the crucible opening / closing arm to the outside. The pressure means and a crucible fixing release cylinder that pressurizes the crucible opening / closing arm inwardly to release the engagement between the crucible opening / closing body and the restraining portion.

A cut surface is provided on the flange of the crucible at a right angle to the mating surface of the crucible and engages with a part of the support.

In the crucible, the side wall and the bottom wall have substantially the same thickness.

[0009]

A flange is provided on the outside of the edge of the opening of each part divided into crucibles which are vertically divided into crucibles, and the flanges are supported by the flange support. Press the upper part of the crucible flange with the crucible opening and closing body to fix it, and push it inward from both sides of the flange to release the fixation.

The crucible opening / closing arm has a structure that can be moved by a crucible fixing / releasing cylinder. The arm constantly stops the movement of the crucible opening / closing body for pushing the flange inward,
The movement of the arm causes the opening / closing body to be disengaged from the tip of the arm, and the lower part of the crucible divided with the upper part of the crucible pushing the flanges inward from both sides as a fulcrum is opened.

A cut surface is provided on the flange of the crucible at a right angle to the crucible mating surface, the cut surface is positioned with respect to the crucible engaged with a part of the support, and when the crucible opening / closing body pushes the flange inward, A crucible divided in balance is opened.

Further, since the thickness of the side wall and the thickness of the lower wall of the crucible are almost equal, the heat when the metal is melted is evenly conducted, and thermal strain is unlikely to occur.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will now be described with reference to FIGS.
It will be described based on. In the figure, 10 is a crucible used for this apparatus. The crucible 10 is formed in the shape of a tapered cylindrical container, has a flange 11 outside the opening, the cylindrical side wall 13 and the bottom wall 12 have substantially the same thickness, and the crucible 10 is vertically divided into two parts at the center to form a part 10a. , 10b.
Reference numeral 15 denotes a mating surface of the portions 10a and 10b, and a notch portion 14 is formed at the upper end position thereof from above. Further, a part of the flange having the cutout portion 14 is cut at a right angle to the cutout portion to form a cut surface 11a. Note that FIG.
2 is a sectional view in which the crucible 10 on the A side is closed, and
The side is a sectional view in which the crucible 10 is opened.

Reference numeral 1 is a melting chamber for melting the metal contained in the crucible 10 by high-frequency power applied to a high-frequency coil 19 wound around the crucible. 2 is a casting chamber having a mold 2b provided at the bottom of the melting chamber.
During melting and casting, the two chambers are pushed up from below by a cylinder (not shown) or the like, and are sealed by an O-ring 20 and a cover (not shown) above the melting chamber. Reference numeral 5 is a furnace body of the melting chamber, 6 is a crucible support which can be inserted into and taken out of the furnace body from above, and 7 is a support cover which is placed on the top of the crucible support and has an opening in the center. A step 6a is provided at the center of the crucible support 6 and the crucible 10 has a step surface.
It has a structure that can be engaged with the cut surface 11a. Step 6
The both ends of a are provided with hills 6c, and the crucible support 6 has a flange 1 of the crucible 10 at an intermediate position between the notches 14 and 14.
The support portion 6b is provided at a position corresponding to 1. Reference numeral 18 is a heat insulating partition wall provided between the crucible 10 and the high frequency coil 19.

Reference numeral 21 denotes a crucible opening / closing body, and a spring 28 is provided between the rear end of the crucible and the crucible support 6 so that the whole structure is pushed forward. Flange fixing support portion 2 for pressing the flange 11 of the crucible 10 from above
2, a flange fixing release portion 23 protruding downward is provided in the lower portion near the tip, and a fixed position setting portion 24 extending downward is also provided in the rear end. It is in a state. Further, a protrusion 25 is provided on the upper portion of the crucible opening / closing body 21 and serves as a knob for moving it backward.

Reference numeral 30 denotes a crucible opening / closing arm which has a U-shape as a whole and can move horizontally on the crucible support 6. A notch 30c is provided at the center of the arm.
The spring 31 is housed in c, and the whole is pushed out by the fixed hill portion 6c. The crucible opening / closing arm 30 extends in parallel with the step 6a from the center to the tip, and the tip constitutes a restraint portion 30a wider than other portions,
The other part constitutes the narrow release part 30b.

Reference numeral 32 is a crucible fixing and releasing cylinder which abuts on the central portion of the crucible opening / closing arm 30, and its tip 32a.
Has a structure in which the arm 30 is pushed inward.

Next, the operation from installation of the crucible 10 to injection of molten metal will be described. First, the crucible 10 is inserted so that the cut surface 11a can engage with the step surface of the hill portion 6c. The crucible opening / closing body 21 is lowered to the outside, and the flange fixing support portion 22 is set so as to ride on the flange 11 by the force of the spring 28. At this time, the restraint portion 30a at the tip of the crucible opening / closing arm 30 has the fixed position setting portion 2 of the crucible opening / closing body 21.
4, the crucible opening / closing body 21 does not move inside. As a result, a force acts on the crucible 10 in the direction of the broken line arrow, and the divided portions 10a and 10b abut on the crucible mating surface 15 to form one crucible.

A metal to be melted is inserted into the crucible 10 and the entire melting chamber and casting chamber are sealed with an O-ring cylinder or the like (not shown). The melting chamber and casting chamber are evacuated and further depressurized to 700 mmHg. After reducing the pressure, an inert gas such as argon is injected from a tank (not shown). After the injection, high-frequency power is applied to the high-frequency coil 19 and the atmosphere is exhausted while further injecting the inert gas to melt the metal in the inert gas. The molten metal does not flow out due to surface tension even if there is a minute gap on the crucible mating surface.

When the metal to be melted is melted, the cylinder 32
Is operated, and the crucible opening / closing arm 30 is pushed inward by the tip 32a. When the arm 30 is pushed inward,
The contact between the restraint portion 30a and the crucible opening / closing body 21 is released.
Therefore, the spring 28 pushes the crucible opening / closing body 21 inward, the flange fixing release portion 23 pushes the flange 11 of the crucible 10 inward, and the bottom wall 12 of the crucible 10 is quickly opened with the bottom 14a of the notch 14 as a fulcrum.

When the bottom wall 12 of the crucible 10 is opened, the melted metal becomes a lump and drops into the mold gate 2a in about 20 to 50 msec from the release command. Then, when an inert gas such as argon gas is injected from the upper part of the gate and pressurized, the molten metal is cast up to the tip of the mold.

In the above embodiment, the crucible opening / closing arm 30 extends from the center to the distal end in parallel with the step 6a, that is, in parallel with the moving direction of the cylinder 32. The setting portion 24 comes into contact with the restraint portion 30a and the fixed position setting portion 24 during casting.
It may have any shape as long as it can be released from the contact with, and may have a curved portion, or may be a hollow disk so that the arm surrounds the crucible. Also, the crucible opening / closing arm 3 is made by the cylinder 32
Although 0 is moved inward, other releasing means other than the cylinder, for example, a rod may be inserted and manually pushed. Further, the spring 31 opens the crucible opening / closing arm 30 to the outside, and the spring 28
Although the crucible opening / closing body 21 is pushed inward by the spring, the spring is not caught in a spring shape or a plate shape, and the spring 31
Alternatively, rubber may be attached to the arm 30 and pulled to the cylinder 32 side. In the case of a hollow disk surrounding the crucible, the arm may be pushed from the outside facing the cylinder 32 to the cylinder 32 side. Further, the flange 11 of the crucible 10 is cut at a right angle to the crucible mating surface 15, that is, parallel to the support body 6, but a wedge-shaped or cylindrical notch is provided in the flange of the mating surface, and a hill is formed in this notch. The structure may be such that a part of the parts can be engaged. Further, in the above-described embodiment, the notch 14 is provided on the flange of the crucible, but this can be omitted.

[0023]

As described above, according to the present invention, unlike the conventional crucible, there is no restraint at the lower part, the distance between the bottom wall of the crucible and the mold is short, and the crucible is forcibly opened from the fixed state. The molten metal is poured into a mold as a lump, and the molten metal is cooled and cast without solidifying.
In addition, since it is a lump, the tip of the sprue is not easily cooled, and when pressurized with an inert gas, the molten metal in the upper part is cast without scattering. Further, since the bottom wall and the side wall of the crucible have substantially the same thickness, thermal strain is unlikely to occur in the crucible and the crucible is not damaged.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an embodiment of a molten metal injection apparatus of the present invention.

2 is a plan view of FIG. 1 with a cover 7 removed.

FIG. 3 is a plan view and a front view of a crucible used in a conventional molten metal pouring device.

FIG. 4 is a vertical cross-sectional view showing a relationship between a crucible and a molten metal used in a conventional molten metal injection device.

[Explanation of symbols]

 1 Melting chamber 2 Casting chamber 2a Gate 2b Mold 5 Furnace body 6 Crucible support 6a Step 6b Support 6c Hill 7 Support cover 10 Crucible 10a, 10b Crucible part 11 Flange 12 Bottom wall 13 Side wall 14 Notch part 15 18 Partition wall 19 High-frequency coil 20 O-ring 21 Crucible open / close body 22 Flange fixing support part 23 Flange fixing release part 24 Fixed position setting part 25 Protrusion 28 Spring 30 Crucible opening / closing arm 30a Resting part 30b Release part 31 Spring 32 Crucible fixing release cylinder

Claims (4)

[Claims] 1. A crucible provided with a flange on the outer side of the edge of the opening of each divided portion, which is formed in a container shape and opens upward, and is divided vertically. A crucible support, a crucible opening / closing body that presses the upper part of the flange of the crucible to fix it, and presses the flange of the crucible inward from both sides at the time of fixing and releasing, and a fixing and releasing means for releasing the crucible opening / closing body. Molten metal injection device. 2. A crucible opening / closing arm having a wide restraining part which the fixing and releasing means always engages with the crucible opening / closing body, a narrow releasing part outside the crucible opening / closing body, and constantly pressurizes the crucible opening / closing arm to the outside. 2. The molten metal pouring apparatus according to claim 1, which comprises a pressurizing means and a crucible fixing release cylinder which presses the crucible opening / closing arm inwardly to release the engagement between the crucible opening / closing body and the restraining portion. 3. The molten metal pouring apparatus according to claim 2, wherein the flange of the crucible is provided with a cut surface that is cut at a right angle to a mating surface of the crucible and that engages with a part of the support. 4. The molten metal pouring apparatus according to claim 2, wherein the side wall and the bottom wall of the crucible have substantially the same thickness.