JPH073267Y2 - High-speed melting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of use) The present invention relates to a high-speed melting apparatus, and more particularly to a high-speed melting apparatus for heating a raw material such as an aluminum alloy contained in a crucible by high-frequency induction heating means and melting it. .

(Prior Art) In a conventional casting process, a large amount of a raw material such as an aluminum alloy was melted in a melting furnace, and then the melted raw material was supplied to a mold by a ladle or the like for casting. In the case of oxidation during the supply at high temperature, or when melting a high melting point raw material, it is difficult to melt a large amount of raw material at once and to supply a high temperature molten metal to the mold with a ladle. was there.

Therefore, recently, as shown in Japanese Patent Publication No. 59-38867, after supplying the amount of raw material required for one casting to the inside of the crucible made of graphite cast iron, the raw material in the crucible is subjected to high frequency induction heating means. Has proposed a high-speed melting apparatus for heating and melting.

(Problems to be Solved by the Invention) However, in the high-speed melting apparatus for melting the raw material by the high-frequency induction heating means, the inside of the crucible is exposed to high temperature and normal temperature which are repeated in a short cycle. For example, when casting an aluminum alloy, the aluminum alloy in the crucible can be heated from room temperature to 75 ° C. in a short time of about one and a half to two and a half minutes.
After being heated to a high temperature of about 0 ° C, it is supplied to the mold, so the temperature inside the crucible rises from room temperature to 750 ° C during heating, and then the temperature rises from 750 ° C to room temperature during pouring. It is repeated in about one and a half to two and a half minutes.
For this reason, since the thermal shock applied to the crucible is extremely large, the conventional graphite crucible cannot withstand the stress strain due to heat and may crack.

In order to solve this problem, the inventor of the present application considered forming the crucible from a ceramic felt in order to improve the thermal shock resistance of the crucible.

However, the crucible made of ceramic felt has a problem that it cannot withstand the impact when the raw materials are charged.

Therefore, the inventor of the present application forms a crucible of a laminated structure composed of a metal skeleton frame and a ceramic felt, which is obtained by forming a skeleton with an inexpensive metal strip body and laminating ceramic felt around the skeleton. Considered to use.

However, this time, when the raw material is heated and melted by the high-frequency induction heating means, an induced current also flows in the skeleton itself made of metal strips, which causes a new problem that the skeleton generates heat and melts. .

In view of the above, the present invention improves the thermal shock resistance of the crucible by forming the crucible from a ceramic felt, and uses a frame made of a metal strip to secure the shock resistance at low cost. The purpose is to prevent heat generation in the crucible itself.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention is to prevent the frame made of metal strips in the portion surrounded by the high frequency induction heating means from forming a closed loop.

Specifically, the solution means taken by the present invention is premised on a high-speed melting device for heating and melting a raw material contained in a crucible by a high-frequency induction heating means, and the crucible is a skeleton formed by a metal strip. And a ceramic felt laminated around the skeleton, and the skeleton at a portion of the laminated structure surrounded by the high frequency induction heating means does not form a closed loop.

(Operation) With the above configuration, the crucible is formed by the laminated structure of the frame formed of the metal strip and the ceramic felt laminated around the frame, and therefore the thermal shock resistance is improved. .

Further, the frame for ensuring the impact resistance is formed by the metal strip, but since the frame in the part surrounded by the high frequency induction heating means does not form a closed loop, the induction heating means heats and melts the raw material. At this time, no induced current is generated in the frame.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS.

FIG. 4 shows a cross-sectional structure of the high-speed melting apparatus A according to the present invention. Reference numerals 10 and 10 denote inverted U-shaped supports disposed on the left and right sides of the high-speed melting apparatus A so as to face each other. An upper portion 10a of the support body extending in the front-rear direction of the body 10 holds a fixed frame 12 having a rectangular horizontal surface at its lower portion.

A moving frame 14 having a rectangular horizontal plane is arranged below the fixed frame 12, and a sliding body 14a fixed to the upper surface of the moving frame 14 is slidable on a rail 12a attached to the lower surface of the fixed frame 12. It is sandwiched, and the moving frame 14 is slidable in the left-right direction with respect to the fixed frame 12. In addition, on the rear side of the fixed frame 12,
A screw 12b rotated by a moving motor 16 placed on the support upper portion 10a of 10 is attached,
A nut 14b fixed to the rear of the moving frame 14 is screwed into the screw 12b, whereby the moving frame 14 moves in the left-right direction as the moving motor 16 is rotationally driven.

The moving frame 14 has a crucible supporting shaft 18 extending in the front-rear direction rotatably supported at a lower right portion thereof via a supporting plate 14c, and the crucible supporting shaft 18 is attached to a lower portion of the moving frame 14. It is attached to the lid tilting cylinder 20 via the link member 18a, whereby the rotary shaft 18 rotates in the axial direction as the lid tilting cylinder 20 is driven.

The crucible support shaft 18 has a large-diameter upper portion 24 on its left side.
Upper part 24 of a cylindrical crucible 24 consisting of a and a smaller diameter lower part 24b
a is held via a ring-shaped support band 22.

Further, the moving frame 14 is provided between its front and rear parts,
A U-shaped lid lifting cylinder holding member 26 is slidably supported in the left-right direction via a cylindrical guide member 14d and a guide rod 14e fitted into the guide member 14d, and the lid is also supported. The elevating cylinder holding member 26 is attached to the lid moving cylinder 12c attached to the fixed frame 12, whereby the lid elevating cylinder holding member 26 is attached to the moving frame 14 as the lid moving cylinder 12c is driven. Move to the left and right.

The cylinder holding member 26 holds the lid lifting cylinder 28 between them, and the lid lifting cylinder 28
28 holds a disc-shaped crucible lid 30 at its lower end.

Around the crucible 24, there is arranged a heating furnace 32 which can be moved up and down by a not-shown elevating means.
An induction coil 34 as high-frequency induction heating means is disposed inside the induction coil 34, and the induction coil 34 surrounds the lower portion 24b of the crucible 24.

Hereinafter, a method of melting the raw material by the high speed melting apparatus A according to this embodiment will be described.

First, after storing the raw material made of an aluminum alloy billet inside the crucible 24, the lid lifting cylinder 28 is driven to move the crucible lid 30 downward to above the raw material, and then,
The induction coil 34 heats and melts the raw material. In this case, the crucible lid 30 prevents the molten aluminum alloy from rising and overflowing from the crucible 24 by being heated.

When the raw material is melted, the lifting device is driven to lower the heating furnace 32 and the induction coil 34, and the lid lifting cylinder 28 is driven to move the crucible lid 30 upward.

Next, the moving motor 16 is driven to move the moving frame 14 to the right, while the lid moving cylinder 12c is driven to move the lid lifting cylinder holding member 26 and the lid lifting cylinder 28.
The crucible lid 30 is moved leftward with respect to the moving frame 14. By doing so, only the crucible supporting shaft 18, the lid tilting cylinder 20, and the crucible 24 held by the crucible supporting shaft 18, which are supported by the moving frame 14, move to the right, and as shown in FIG. First, the crucible 24 approaches the hot water receiving tube 36 which is in communication with the casting mold. Then, the lid tilting cylinder 20 is driven to rotate the crucible support shaft 18 to the right,
As a result, the molten metal is supplied from the opening 24c of the crucible 24 to the molten metal receiving tube 3
Inject 6 and move to the next step, the casting step.

The structure of the crucible 24 will be described below with reference to FIGS. 1 to 3.

The crucible 24 includes a skeleton 40 formed by a metal wire 38 made of stainless steel having a diameter of 1 mm, and the skeleton 40.
It is composed of a laminated structure 44 with a ceramic felt 42 laminated around the periphery of the.

The skeleton 40 includes two U-shaped bodies 40a and 40b arranged in a cross shape on the peripheral wall 44a and the bottom portion 44b of the laminated structure 44, and the laminated structure 4
The circular bodies 40b arranged in the upper portion 44c of 4 in the upper and lower five stages, and the lower portions 44d of the laminated structure 44 arranged in the upper and lower three stages in the upper and lower portions 44d, respectively, are semicircular bodies 40c and U having a diameter slightly larger than the width of the U-shaped body 40a. It is composed of a semi-circular body 40d having a diameter slightly smaller than the width of the character 40a, and the uppermost circular body 40b holds each other by penetrating the upper end annular portion of the U-shaped body 40a. 40b and the large-diameter semicircular body 40c are U-shaped bodies 40a due to the elastic force of each of them.
The semi-circular body 40d having a small diameter is fitted and held on the outer side of the U-shaped body 40a by its elastic force.

Further, U is formed at a portion where the U-shaped body 40a intersects at the bottom portion 44b of the laminated structure 44 and at a lower portion 44d of the laminated structure 44.
The U-shaped body 40a at the intersection of the character-shaped body 40a and the semicircular bodies 40c and 40d has, for example, an insulator 40e having an inner diameter of 2 mm and a length of 20 mm.
The U-shaped body 40a and the U-shaped body 40a and the semicircular bodies 40c and 40d are insulated from each other by these insulators 40e.

In addition, as the metal strip in the above embodiment, a wire 38
Instead of this, a metal strip may be used.

By the above, since the skeleton 40 in the portion surrounded by the high frequency induction heating means (induction coil 34) does not form a closed loop, when the induction coil 34 heats and melts the raw material inside the crucible 24, Although the skeleton 40 is made of a metal strip, no induced current is generated. Therefore, the skeleton 40 does not heat up and does not melt.

The ceramic felt 42 has, for example, an average diameter of 2 to 3 μ.
Using a mixture obtained by compressing and molding a ceramic short fiber of alumina and silica of m, it is laminated on the skeleton 40 as follows.

That is, first, the laminated structural body 44 corresponds to the inner surface shape, and to the outer peripheral surface of a bell-shaped wooden mold having a large number of through holes, from the top of the ceramic short fibers containing a binder and moistened from above. While dropping and supplying, the inside of the wooden mold is evacuated, and ceramic short fibers are laminated on the outer peripheral surface of the wooden mold. Next, a frame is attached to the outside of the laminated ceramic short fibers.
After covering with 40, ceramic short fibers are laminated on the outside of the skeleton 40 in the same manner as described above, and this laminated body is dried to obtain a laminated structure 44.

(Effects of the Invention) As described above, according to the high-speed melting apparatus of the present invention, the crucible is formed by the laminated structure of the frame made of metal strip and the ceramic felt, so that the thermal shock resistance of the crucible is improved. In addition, since the frame surrounded by the high frequency induction heating means does not form a closed loop, an induced current is not generated in this frame, so that the crucible itself can be prevented from generating heat.

[Brief description of drawings]

1 to 5 show a high-speed melting apparatus according to an embodiment of the present invention. FIG. 1 is a cutaway perspective view of a crucible, FIG. 2 is a cross-sectional view of the crucible, and FIG. 3 is a framework of the crucible. Is a perspective view showing a part of FIG. 4, FIG. 4 is a partially cutaway sectional view of the high-speed melting apparatus, and FIG. A: High-speed melting device 24: Crucible 34: Induction coil (high-frequency induction heating means) 38: Wire (metal strip) 40: Skeleton 42: Ceramic felt

Claims (1)

[Scope of utility model registration request] 1. A high-speed melting apparatus in which a raw material contained in a crucible is heated and melted by high-frequency induction heating means, wherein the crucible is laminated on a skeleton formed of metal strips and around the skeleton. A high-speed melting apparatus comprising a laminated structure with a ceramic felt, and a skeleton in a portion of the laminated structure surrounded by the high frequency induction heating means does not form a closed loop.