JP3051970B2 - Molten metal injection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a crucible is used in this type of molten metal pouring apparatus, and a crucible as shown in FIG. 3 is known. In the crucible 51 shown in the figure, when the metal melted therein is poured into a mold, the crucible is inclined and poured from an outflow guide groove 52 formed at an upper opening edge of the crucible. In general, the amount of the alloy used for this type of precision casting is often as small as several grams to several tens of grams. Therefore, when such a small amount of metal is melted and poured into the mold using the crucible as described above, the molten metal is cooled and solidified when passing through the position of the outflow guide groove 52 having a relatively low temperature, Not only is there a problem in the casting operation, but there is a problem that an appropriate casting temperature cannot be maintained, and a loss due to adhesion in the case of a noble metal. In order to prevent early solidification, it is conceivable to heat the molten metal to an appropriate temperature or higher. However, in such a case, problems such as a roughened casting surface, formation of a casting cavity, and deterioration of the metal structure are separately caused.

[0003] The applicant of the present invention 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 entirely vertically divided. Each divided part 60
The supported portions 68a, 6b are located outside the edges of the openings 60a, 60b.
8b are provided. As shown in FIG. 3A, the crucible 60 is supported by a support 70, and the lower portion is restrained by a restraint 71. At this time, the high-frequency coil 6
9 supplies high-frequency power to the metal 7 stored in the crucible
Melt 5. Then, as shown in FIG.
When 0 is moved upward or the constraint 71 is moved downward, the constraint is released. Each part 6 divided when the constraint was released
0a and 60b open the lower part to the outside by own weight. Thereby, 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 pouring apparatus of No. 7540, the metal to be melted in the crucible 60 is disposed substantially at the center of the high-frequency coil 69, so that the lower leg 64 of the crucible 60 needs to be long. For this reason, the molten metal was cooled during 100 to 200 msee until it dropped into the mold gate, solidification started, and complete casting was not possible. Also, since this crucible opens outward by its own weight, the molten metal falls down in a gradually elongated shape, so the part that first reached the gate was cooled by the mold runner until the last part reached and solidified by argon. Even when pressurized with an inert gas such as a gas, the casting may not be completely cast to the tip of the mold. Further, when the inert gas was pressurized, the upper melting portion was sometimes scattered. In addition, since the bottom wall 65 of the crucible 60 is thicker than the side walls, the crucible was likely to be thermally distorted due to melting of the metal, and was easily damaged. For this reason, it is necessary to raise the melting temperature, and there is a problem that a casting cavity is easily generated.

[0005]

SUMMARY OF THE INVENTION A crucible which is opened upward and is formed in a container shape and which is vertically divided as a whole, and which is provided with a flange outside the edge of the opening of each of the divided portions, a crucible support for supporting the flange, to fix pressing the upper flange of the crucible, at a fixed release, the crucible opening and closing member to press inward the flange of the crucible from both sides, in a state where the crucible is closed crucible opening Body and
The crucible opening / closing body is restrained in contact, and the crucible is split when the crucible is split.
It is constituted by fixed releasing means for releasing the contact with the opening and closing body .

[0006] Further , the crucible is closed with the fixing and releasing means.
Wide restraint portion and a crucible opening and closing arm having its other is narrow release part, and pressurizing means for pressurizing the crucible closing arm always outwardly into contact with the crucible opening and closing member is in the state Flip was, the The crucible opening / closing arm is constituted by a crucible fixing / releasing cylinder which presses the crucible opening / closing arm inward and releases the contact between the crucible opening / closing body and the restricting portion.

[0007]

In the above 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 portion divided into a vertically divided crucible, and the flange is supported by a flange support. The upper part of the flange of the crucible is pressed and fixed by the crucible opening / closing body, and is pressed inward from both sides of the flange to release the fixing.

The crucible opening / closing arm has a structure that can be moved by a crucible fixing / releasing cylinder, and always stops the movement of the crucible opening / closing body in which the arm pushes the flange inward.
The movement of the arm causes the opening / closing body to be detached from the tip of the arm, and the lower part of the divided crucible is opened with the upper part of the crucible pressing the flange inward from both sides as a fulcrum.

[0011]

In addition, since the thickness of the crucible is substantially equal to the thickness of the side wall and the low wall, heat at the time of melting the metal is evenly conducted, and heat distortion hardly occurs.

[0013]

1 and 2 showing an embodiment of the present invention.
It will be described based on. In the figure, reference numeral 10 denotes a crucible used in this device. The crucible 10 is formed in a tapered cylindrical container shape, has a flange 11 outside the above opening, the thickness of the cylindrical side wall 13 and the bottom wall 12 is almost the same, and the whole is vertically divided into two parts at the center to form a portion 10a. , 10b.
Reference numeral 15 denotes a mating surface of the portions 10a and 10b, and a cutout portion 14 is formed at an 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. FIG.
2 is a cross-sectional view in which the crucible 10 is closed on the A side, and FIG.
The side is a sectional view in which the crucible 10 is open.

Reference numeral 1 denotes a melting chamber that melts the metal housed in the crucible 10 by high-frequency power applied to a high-frequency coil 19 wound around the crucible. Reference numeral 2 denotes a casting chamber having a mold 2b provided at the lower part of the melting chamber.
The two chambers are pushed up from below by a cylinder or the like (not shown) during melting and casting, and are sealed by an O-ring 20 and a cover (not shown) at the top of the melting chamber. Reference numeral 5 denotes a furnace body of the melting chamber, 6 denotes a crucible support that can be inserted and removed from the upper part of the furnace body, and 7 denotes a support cover placed on the upper part of the crucible support and having a central opening. The center of the crucible support 6 has a lower portion 6a of a step which is lower than other portions.
The outside of the lower part 6a of the step is higher than the center part,
Two hills 6c are provided so as to sandwich the central part. hill
The step surface at the boundary between the part 6c and the low part 6a of the step is a crucible 10
Is in contact with the cut surface 11a of the
It has a structure that can be engaged with the support 6. In addition,
The crucible support 6 has a hill 6 parallel to the crucible mating surface 15.
The crucible flange 11 is mounted at an intermediate position between c and the hill 6c.
A support portion 6b is provided at a position where it can be placed. In addition, 1
Reference numeral 8 denotes a heat-insulating partition provided between the crucible 10 and the high-frequency coil 19, and reference numeral 7 denotes a support cover provided above the crucible support 6.

Reference numeral 21 denotes a crucible opening / closing body, and a spring 28 is provided between the rear end of the crucible support 6 and the crucible supporting body 6, so that the whole is pushed forward. Flange fixing support 2 for pressing down the flange 11 of the crucible 10 from above
2, a lower portion near the front end is provided with a flange fixing and releasing portion 23 projecting downward, and a rear end is also provided with a fixing position setting portion 24 extending downward, and the opening / closing body 21 is formed as a whole. It has a shape. Further, a projection 25 is provided on the upper part of the crucible opening / closing body 21, and serves as a knob for moving the projection rearward.

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 stored in the hill portion 6c, and the hill portion 6c is fixed.
The entire arm 30 is pushed outward.
The crucible opening / closing arm 30 has a low step from the center to the tip.
It extends in parallel so as to surround the portion 6a , the tip forms a restraining portion 30a wider than other portions, and the other portion has a narrower release portion 3a.
0b.

Reference numeral 32 denotes a crucible fixing release cylinder which contacts the central portion of the crucible opening / closing arm 30, and its tip 32a
Has a structure for pushing the arm 30 inward.

Next, the operation from the installation of the crucible 10 to the injection of the molten metal will be described. First, the crucible 10, mosquitoes
The cut surface 11a is a step at the boundary between the hill portion 6c and the low portion 6a of the step.
Insert so that it can engage with the difference surface . The crucible opening / closing body 21 is opened outward, 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 constraining portion 30a at the tip of the crucible opening / closing arm 30 abuts and is fixed to the fixed position setting portion 24 of the crucible opening / closing body 21, whereby 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 dashed arrow, and the divided portions 10a and 10b abut on the crucible mating surface 15,
Form one crucible.

A metal to be melted is inserted into the crucible 10, and the whole of the melting chamber and the casting chamber integrated with each other is sealed with an O-ring cylinder or the like (not shown). The melting chamber and the casting chamber are evacuated and further reduced to 700 mmHg. After the pressure reduction, 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 the inert gas is injected, so that the metal is melted in the inert gas. It should be noted that the molten metal does not flow out due to surface tension even if there is a minute gap in the crucible mating surface.

When the molten metal 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,
Crucible open / close body restrained by wide restraint portion 30a
21 moves to the narrow release portion, and the contact between the restraining portion 30a and the crucible opening / closing body 21 is released. For this reason, the crucible opening / closing body 21 is pushed inward by the spring 28, and
3 pushes the flange 11 of the crucible 10 inward, and the notch 1
The bottom wall 12 of the crucible 10 is quickly opened with the bottom 14a of the base 4 as a fulcrum.

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

In the above embodiment , the crucible opening / closing arm 30
From the center to the tip, it is parallel to the lower part 6a of the step.
Chi, although is parallel to the direction of movement of the cylinder 32, constant at all times and the fixed position setting unit 24 of the restraining portion 30a and the crucible closing body 21 abuts the restricting portion 30a and the fixed position setting unit 24 to the casting during Any shape may be used as long as the contact can be released, and it may have a curved portion, and may be a hollow disk so that the arm surrounds the crucible. Further, the crucible opening / closing arm 30 is moved inward by the cylinder 32, but other releasing means other than the cylinder, for example, a rod may be inserted and pushed manually. or,
Although the crucible opening / closing arm 30 is pushed outward by the spring 31 and the crucible opening / closing body 21 is pushed inward by the spring 28, the spring is not caught in a spring or plate shape, and rubber is attached to the arm 30 instead of the spring 31. When the arm is a hollow disk surrounding the crucible, the arm may be pushed toward the cylinder 32 from the outside facing the cylinder 32. Further, in the above embodiment, the notch 14 is provided in the flange of the crucible, but this may be removed.

[0023]

As described above, according to the present invention, unlike the conventional crucible, there is no restriction body 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. Then, the molten metal is poured into a mold in a lump, and the molten metal is cooled and cast without solidification.
In addition, since it is one lump, the tip of the gate is hard to be cooled, and when pressurized with an inert gas, the upper molten metal is cast without being scattered. Further, since the thickness of the bottom wall and the side wall of the crucible are almost the same, the crucible is hardly subjected to thermal distortion and does not break.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of a molten metal injection device of the present invention.

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

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

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Melting room 2 Casting room 2a Gate 2b Mold 5 Furnace body 6 Crucible support 6a Low part 6b of a step Support part 6c Hill part 7 Support body cover 10 Crucible 10a, 10b Crucible part 11 Flange 12 Bottom wall 13 Side wall 14 Notch 15 Crucible mating surface 18 Partition wall 19 High frequency coil 20 O-ring 21 Crucible opening / closing body 22 Flange fixing support part 23 Flange fixing release part 24 Fixed position setting part 25 Projection 28 Spring 30 Crucible opening / closing arm 30a Restraining part 30b Release part 30c Notch 31 Spring 32 Crucible Fixed release cylinder

Claims (2)

(57) [Claims] 1. A crucible having an upper opening and formed in a container shape and entirely divided vertically, and having a flange provided on an outer edge of the opening of each of the divided portions, and supporting the flange of the crucible. A crucible support, a crucible opening / closing body that presses and fixes the upper part of the flange of the crucible and presses the flange of the crucible inward from both sides when fixed and released, and a crucible with a tip when the crucible is closed. Open
Wide restraint that abuts the closing body, and release that is narrow
A crucible opening / closing arm having
Pressing means for pressing the opening / closing arm, and the crucible opening / closing arm
The crucible opening and closing body and the restraint
A molten metal injection device, comprising: a fixed release means having a crucible fixed release cylinder for breaking contact . 2. The crucible according to claim 1, wherein a side wall and a bottom wall are substantially equal.
The molten metal injection device according to claim 1, wherein the molten metal is a thickness.