JPH0141425B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a hot chamber type die casting machine, and particularly to a hot chamber type die casting machine, in which molten metal at a temperature of about 600°C to 1650°C, so-called
This invention relates to a die-casting device that fills a mold with a high-temperature molten metal of about 600°C to 1650°C and performs casting.

<Prior Art> Conventionally, this type of die casting apparatus has the structure shown in FIG. 4. Such a die-casting device constitutes a holding furnace A _' by suspending and housing a heat-insulating pot _a1 ' inside a machine frame _a2 ' for storing molten metal; sleeve
The tip of a runner 20 extending from the lower end opening of B' to the sprue 1b of the mold 1 is connected to the sprue 1b via the nozzle 6, and the plunger of the injection cylinder E is connected to the sprue 1b of the mold 1 through the nozzle 6. Insert the tip e ₁ , and the forward movement (downward movement) of the tip e ₁ will cause the sleeve to open.
The structure is such that the molten metal flowing into B', a so-called pressurizing chamber, is extruded under pressure and fed through a runner 20, and is filled into the mold 1, a so-called cavity, from a nozzle 6 at the tip of the molten metal.

However, this die-casting device is an injection mechanism in which the plunger chip e ₁ applies pressure from above into the sleeve B' to extrude and pressure-feed the molten metal to fill it into the mold ₁ .
During the forward movement (during machining), impact vibrations are transmitted from above to the pot wall and the hanging edge of the heat-insulating pot _A1 ', which is suspended in the machine frame _A2 ', and these parts are damaged by die-casting. There was a risk that metal fatigue such as cracks would grow significantly due to the effects of repeated vibrations during operation of the aircraft, leading to damage, which was a fatal flaw that could not withstand long-term use.

In addition, since the heat-retaining pot a ₁ ' of holding furnace A' is generally made of heat-resistant metal such as molybdenum steel or cast iron, it cannot withstand the heat received from the high-temperature molten metal of about 600℃ to 1650℃. They had the drawbacks of being highly impact-resistant and having poor thermal shock resistance, which meant that they needed to be repaired or replaced in a short period of time. At the same time, since it is a metal, a large amount of heat is radiated to the outside, making it difficult to control the temperature of the molten metal.

Furthermore, the sleeve B', which is immersed in the molten metal of the heat-insulating pot _a1 ', is also generally made of the above-mentioned heat-resistant metal, and as a result of being immersed in the molten metal, it is always in a high temperature state. Because of its position, it has poor thermal shock resistance and has a reciprocating plunger tip e _1.
The wear was severe.

Therefore, in order to solve such problems, Figure 2 of Japanese Patent Application Laid-Open No. 55-5139 or Japanese Patent Application Laid-Open No. 53-1632
There is a die casting device illustrated in FIG. 2 of the publication. In the former die-casting device, in order to maintain the holding strength of the heat-insulating pot against shock vibrations from above when the plunger tip moves forward (when pressurized), there is a space between the outer surface of the heat-insulating pot and the inner surface of the machine frame. It is filled with particulate ceramics. However, because it is made of particulate ceramic, it cannot provide sufficient rigidity to protect the heat-retaining pot from impact vibrations, and is therefore not satisfactory.

Further, a ceramic coating agent is applied to the inner surface of the heat-retaining pot, so that the pot wall has a double-walled structure with excellent thermal shock resistance, consisting of a metal wall and a ceramic wall. However, there is a drawback that the ceramic wall is easily damaged due to the large difference between the coefficient of thermal expansion of metal and that of ceramics.

On the other hand, the latter die-casting device has a heat insulating pot (pot 24) made of ceramics and a machine frame (heat insulator body 4) with refractory bricks 26 attached to the inner surface.
Insulating layer 25 made of ceramics that holds the heat-retaining pot
This is a holding furnace that has excellent impact resistance to retain the heat of the stored molten metal and protect the heat-insulating pot from impact vibrations.

However, although the above-mentioned ceramics used to make thermal pots have better thermal shock resistance and heat retention than metals, they have poor strength against high-temperature molten metals of 600 to 1,650℃, especially in the high temperature range of 1,000℃ or higher. The hardness and fracture toughness values are low, and the thermal shock resistance and chemical resistance are rapidly deteriorated. It was impossible to use.

<Problems to be solved by the invention> The technical problems to be solved by the invention are as follows:
You can expect high-temperature thermal shock resistance against high-temperature molten metal up to about 1650℃, rigidity such as durability, and high heat retention.
Moreover, it is an object of the present invention to provide a hot chamber type die-casting device that is equipped with an injection mechanism that does not cause a drop in the temperature of the molten metal when filling the mold with the molten metal and does not apply load stress such as impact vibration to the holding furnace.

<Means for Solving Technical Problems> The technical means taken by the present invention to solve the above problems is to fire a heat-insulating pot for storing molten metal using a ceramic material, and to place the ceramic heat-insulating pot inside the machine frame. At the same time, a ceramic heat insulating material made by embedding a heating element in the ceramic material and firing it integrally is closely interposed between the inner surface of the machine frame and the outer surface of the heat insulating pot, and the opening of the heat insulating pot is A holding furnace is constructed by closing the part with a ceramic lid body, and a suction cylinder is installed upright with its lower end opening located inside the heat insulating pot of the holding furnace, and the one end opening is placed inside the heating pot of the mold. The molten metal in the holding furnace is sucked up and injected into the suction cylinder of the cross-shaped ceramic sleeve made of fired ceramic material by connecting the injection cylinder connected to the sprue in a cross shape. The plunger tip of a suction cylinder for pouring molten metal is inserted into the injection cylinder, and the plunger tip of an injection cylinder for filling a mold with the molten metal sucked up and poured into the injection cylinder is inserted, and the above-mentioned ceramics are made of
A solid solution with α-Si ₃ N ₄ structure, M x (Si, AI) ₁₂
(O, N) ₁₆ (In the above formula, M is Mg, Ca, Y, etc.)
α-Sialon granular crystals 60vol% and β-
It is characterized by being an α-sialon sintered body consisting of a dense composite structure called the “partially stabilized” α-sialon region, where 40 vol% of Si ₃ N ₄ columnar crystals coexist.

<Function> According to the technical means of the present invention described above, the heat insulating pot and the cross-shaped sleeve constituting the holding furnace contain 60 vol% of α-sialon granular crystals and 40 vol% of β-Si ₃ N ₄ columnar crystals. The coexisting region “partial stabilization” α
- Excellent mechanical properties such as strength, hardness, and fracture toughness in the composition range called Sialon region,
In addition, α- has excellent thermal shock resistance and chemical resistance.
It is integrally molded from a sialon sintered body, which provides high temperature thermal shock resistance and high heat retention against high-temperature molten metal of about 600 to 1650°C. The molten metal stored in the heat-insulating pot is removed from the heat-insulating pot by the double action of the suction plunger tip inside the suction cylinder of the cross-shaped sleeve immersed in the molten metal and standing upright. The molten metal is sucked up and poured into the communicating injection cylinder, and is injected and filled into the mold by the reciprocal movement of the injection plunger tip within the injection cylinder.

<Example> An example of the present invention will be described based on the drawings.
In the figure, A is a holding furnace, and B is a ceramic cross-shaped sleeve. The molten metal stored in the holding furnace A is temporarily sucked up and taken out from the holding furnace A by this cross-shaped sleeve B, and then the molten metal is is filled into the mold 1, the so-called cavity 1a.

Holding furnace A consists of a ceramic heat-insulating pot _A1 that is internally housed within a machine frame _A2 , with a ceramic heat-insulating material _A3 closely interposed between the outer surface of the pot wall and the inner surface of a machine frame _A2 . Install and configure.

The Insulating Pot _A1 is made of a ceramic material that has excellent impact resistance, thermal shock resistance, durability, etc., and is fired into a substantially cylindrical shape. Attach heat insulating material _A3 to the outside surface and the lower surface of the bottom wall.

Thermal insulation material A ₃ functions to constantly heat the molten metal stored in the insulation pot A ₁ and maintain it at a constant temperature, and is made of ceramic material ( A heating element 2 serving as a heat source is embedded in a raw ceramic material) and integrally fired to a thickness that allows it to be closely interposed between the outer surface of the pot wall of the heat-retaining pot _A1 and the inner surface of the machine frame _A2 .

Therefore, the heat insulating pot A ₁ is kept warm by the ceramic heat insulating material A ₃ interposed therein, which closely matches the outer surface of the pot wall of the ceramic heat insulating pot A ₁ and closely matches the inner surface of the machine frame A _{2 .} It has an integrated structure that integrates the machine frame _A2 and the machine frame A2 to provide durability, and the ceramic heat-insulating pot _A1 provides thermal shock resistance.The heat-insulating pot _A1 and the ceramic heat-insulating material _A3 provide durability. It has a holding furnace A structure that provides impact resistance and high heat retention.

In addition, in the figure, 3 is a frame that integrally installs the holding furnace A to the die-casting machine C, and 4 is a ceramic lid that closes the opening of the heat-insulating pot _A1 to prevent oxidation of the stored molten metal. A molten metal feed pipe 5 directly connected to a parent furnace such as a melting furnace is connected to the lid 4 in a penetrating manner, so that molten metal is periodically supplied from the parent furnace.

The cross-shaped sleeve B is a heat-retaining pot by the follow-up interlocking operation of the suction cylinder D and the injection cylinder E.
This is to form an injection passage for once sucking up and taking out the molten metal from A ₁ and filling it into the cavity 1a of the mold 1.The lid body 4 is penetrated and the lower end opening side cylinder part is inserted into the molten metal of the heat insulating pot A ₁ . A suction cylinder b ₁ is immersed in water and placed upright, and the opening at one end is connected to the sprue 1 of the mold 1.
an injection cylinder b ₂ connected to b via a nozzle 6;
Both b ₁ and b ₂ connected in a cross shape are heat resistant,
It is constructed by firing a ceramic material with excellent durability, etc., and is installed on the holding furnace A.

And this ceramic cross-shaped sleeve B
A suction cylinder D is placed upright above the upper end opening of the suction cylinder b ₁ and the plunger tip d ₁ of the cylinder D is slidably inserted into the suction cylinder b ₁ . , an injection cylinder E is placed horizontally on the side of the other end opening of the injection cylinder b ₂ , and the plunger tip e ₁ of the cylinder E is inserted into the injection cylinder.
b Insert freely into ₂ .

In addition, suction cylinder D and injection cylinder E
is connected to the die casting machine C, and at the same time as the suction operation of the suction cylinder D, that is, the suction and backward movement (upward movement) of the plunger tip _d1 , is completed, the injection operation of the injection cylinder E follows and the plunger tip is This is to move e ₁ forward under pressure.

In the figure, F is a suction device installed in communication with the cavity 1a of the mold 1, and this suction device F
is connected to the die-casting machine C so as to operate simultaneously with the start of the suction operation of the suction cylinder D.

Thus, the plunger tip _d1 of the suction cylinder D is made to wait at the lower limit within the suction cylinder body b1 of the cross-shaped sleeve B suspended in the molten metal, and the plunger tip _d1 of the injection cylinder E is suspended. The jet e ₁ is placed on standby at the retreat limit within the injection cylinder b ₂ on the side of the cylinder E from the communication intersection with the suction cylinder b ₁ (FIG. 1). Then, during the injection process in the casting cycle (each cycle operation) of the die casting machine C, the suction cylinder D is operated to move the plunger tip d ₁ back, and the molten metal in the holding furnace A is transferred to the injection cylinder.
At the same time as the plunger tip _d1 enters the suction cylinder _b2 which is the upper limit (Fig. ₂ ), the injection cylinder E is operated to pour the molten metal into the plunger tip e. Move ₁ forward and insert the injection cylinder.
The molten metal sucked up and poured into b ₂ is filled into the cavity 1a of the mold 1 through the nozzle 6 (FIG. 1).

The plunger tip d ₁ of the suction cylinder D is moved forward at the same time as the plunger tip e ₁ of the injection cylinder E moves back and returns to the backward limit, waits at the lower limit, prepares for the next backward movement, and repeats the above steps again. By repeating the operation and interlocking operation with the injection cylinder E, the cavity 1a of the mold 1 is filled with the molten metal in the holding furnace A.

However, the holding furnace A is used as an injection mechanism for sucking up and injecting the molten metal in the heat retention pot _A1 using the cross-shaped sleeve B.
The molten metal can be filled into the cavity 1a of the mold 1 without applying stress such as impact vibration to the mold.

Next, the compositional structure of the ceramics from which the above-mentioned holding pot a ₁ , heat insulating material a ₃ , cross-shaped sleeve B, and lid 4 are made will be briefly explained.

Such ceramics are solid solutions with an α-Si ₃ N ₄ structure, and are composed of α-sialon represented by Mx (Si, AI) ₁₂ (O, N) ₁₆ (in the above formula, M is Mg, Ca, Y), etc. α-Sialon material with a dense composite (solid solution) structure obtained by firing 60 vol% of granular crystals (α phase) between 40 vol% of columnar crystals (β phase) of β-Si ₃ N ₄ to form a solid solution. It is a sintered body, and has strength, hardness, fracture toughness, _etc. in the composition range called the "partially stabilized" α-sialon region, which is a region where 60 vol% of α- _sialon granular crystals and 40 vol% of β-Si 3 N 4 columnar crystals coexist. It has excellent mechanical properties, as well as thermal shock resistance and chemical resistance.

Thus, the hot chamber type die-casting apparatus of this embodiment has a heat-insulating pot A1 and _a suction cylinder B of a holding furnace A, which are integrally stored in a machine frame _A2 in a close relationship with a heat-insulating material _A3 . The cross-shaped sleeve B, which is formed by communicating the injection cylinder B ₁ and the injection cylinder B ₂ into the same body, is heated to 600 to 1650°C.
For high-temperature molten metals up to 1,000℃, especially in the high-temperature range exceeding 1,650℃, there is a region where 60 vol% of α-sialon granular crystals and 40 vol% of β-Si ₃ N ₄ columnar crystals coexist. Partially stabilized α-sialon sintered material with excellent mechanical properties such as strength, hardness, and fracture toughness in the composition range called “α-sialon region”, as well as excellent thermal shock resistance and chemical resistance. By firing them together, it has excellent high-temperature thermal shock resistance that can withstand high temperatures in the range of 1000℃ to 1650℃, durable rigidity, and high heat retention. A suction cylindrical body that communicates the filling of molten metal from the pot a ₁ into the cavity 1a of the mold C with the same body of the cross-shaped sleeve B.
Suction by the following reciprocating motion of both plunger tips d 1 _and e ₁ inserted into b ₁ and injection cylinder b ₂ , respectively,
As an injection mechanism that performs a series of processes with injection, the heat of the molten metal heated and maintained at a constant temperature in the holding furnace A is dissipated to the outside or taken away, and the temperature remains constant without decreasing. Moreover, it is possible to fill the cavity 1a of the mold C without applying load stress such as impact vibration to the holding furnace A.

In addition, although the cross-shaped sleeve B in which the suction cylinder b ₁ of the cross-shaped sleeve B is suspended and immersed in the molten metal of the heat-insulating pot a ₁ has been described in detail as an installation form, the suction cylinder b It is also optional that the opening at the lower end of the heat-retaining pot _a1 is extended until it touches the bottom of _the pot, so that the suction cylinder _b1 is placed directly on the bottom of the pot. In this case, an inflow hole is opened in the suction cylinder b ₁ near the lower limit where the plunger tip d ₁ of the suction cylinder D waits, and the molten metal flows into the cylinder b _1. do as you like.

Furthermore, in the above embodiment, the cruciform sleeve B
The suction cylinder b ₁ was vertically suspended and the cross-shaped sleeve B was installed upright on the holding furnace A, but the suction cylinder b ₁ was suspended diagonally at a desired angle of inclination. The cross-shaped sleeve B may be erected to form a shape, but this is optional.

<Effects of the Invention> Since the hot chamber die-casting apparatus of the present invention is constructed as described above, it exhibits the following effects.

For injection, the molten metal is communicated from the holding furnace through the suction cylinder of the holding furnace through the reciprocating motion of the plunger tip of the suction cylinder inserted into the suction cylinder of the cross-shaped sleeve installed on the holding furnace. The molten metal drawn up from the holding furnace and poured into the injection cylinder is filled into the mold by the reciprocating motion of the plunger tip of the injection cylinder inserted into the injection cylinder. As a result, the holding furnace is not subjected to load stress such as assault vibrations during filling, and the temperature of the molten metal is maintained at a constant level without being dissipated to the outside or taken away and causing the molten metal temperature to drop. It can be filled into the mold from the holding furnace. Therefore, it is possible to prevent the generation of solidified pieces during injection due to a decrease in the temperature of the molten metal, thereby making it possible to cast a high quality product.

A heat-retaining pot that is closely integrated and housed in a machine frame by means of a heat-insulating material, and a tenth structure in which the heat-insulating material, a suction cylinder, and an injection cylinder are connected in the same body in a cross shape. Glyph sleeve, 600~1650
For high-temperature molten metals up to about ℃, strength, hardness, _and fracture are reduced in the composition range called the "partially stabilized" α-sialon region, where 60 vol% of α-sialon granular crystals and 40 vol% of β-Si 3 N ₄ columnar crystals coexist. It is made of an α-sialon sintered body that has excellent mechanical properties such as toughness, thermal shock resistance, and chemical resistance.
It has high-temperature thermal shock resistance that can withstand temperatures in the high temperature range of 1650℃, high rigidity such as durability, and high heat retention, making it possible to inject high-temperature molten metal from 600 to 1650℃. Moreover, since the opening of the insulating pot of the holding furnace is closed with the lid made of the α-sialon sintered body, oxidation of the molten metal stored in the insulating furnace is prevented and the heat retaining effect of the heat insulating material is improved. Combined with this, the heat retention properties of the holding furnace are dramatically increased, and it is possible to reliably maintain the temperature of high-temperature molten metal at temperatures ranging from 600 to 1,650 degrees Celsius.

Thus, the intended purpose can be achieved.

[Brief explanation of drawings]

1 to 3 are sectional views of essential parts showing an embodiment of the present invention, and FIG. 4 is a sectional view showing a conventional example. In addition, in the figure, A: Holding furnace, _a1 : Insulating pot, _a2 : Machine frame, _a3 : Heat insulating material, B: Cross-shaped sleeve, _b1 : Suction cylinder, _b2 : Injection cylinder , D: suction cylinder, d ₁ : suction cylinder plunger tip, E: injection cylinder, e ₁ : injection cylinder plunger tip, 1: mold, 2: heating element.

Claims (1)

[Claims] 1. A heat-insulating pot for storing molten metal is fired from a ceramic material, and the ceramic heat-insulating pot is housed within a machine frame, and a heating element is made of ceramic material between the inner surface of the machine frame and the outer surface of the heat-insulating pot. A holding furnace is constructed by closely interposing a ceramic heat insulating material that is embedded and fired integrally inside the heat insulating pot and closing the opening of the heat insulating pot with a ceramic lid. A suction tube that stands upright with an opening located inside, and an injection tube that connects one end of the opening to the sprue of a mold, are connected in a cross shape, and are fired from a ceramic material. The plunger tip of the suction cylinder that draws up and pours the molten metal in the holding furnace into the injection cylinder is inserted into the suction cylinder of the letter-shaped sleeve, and the molten metal drawn up and poured into the injection cylinder is inserted. The plunger tip of the injection cylinder is inserted to fill the mold into the mold.
A solid solution with Si ₃ N ₄ structure, MX (Si, AI) ₁₂ (O,
N) ₁₆ (In the above formula, M is Mg, Ca, Y, etc.) α-sialon granular crystals 60 vol% and β-Si ₃ N ₄
“Partial stabilization” region where columnar crystals coexist with 40vol%
A hot chamber die-casting machine characterized by an α-sialon sintered body consisting of a dense complex structure called an α-sialon region.