JPH0149582B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an injection device for molten metal used in a die-casting machine, and more particularly to an injection device for injecting high-temperature molten metal at 600 to 1200°C.

(Prior art and problems) Conventionally, the injection device of a hot chamber die-casting machine has a structure as shown in FIG.
A goose neck 33 for injecting molten metal into the mold 32 is attached in a suspended state inside the heat retaining pot 31.
is held on a heating table 34.

The injection device configured as described above causes the plunger 35 to perform a piston motion for each shot, and also opens and closes a movable mold (not shown), but the impact at this time is transmitted through the nozzle 36 to the goose neck 33 and the heat-insulating pan 3.
1, there was a problem in that if the number of shots was increased, the support part and bottom part of the gooseneck 33, and the pot 31 itself would be damaged relatively quickly.

The problem mentioned above is that the Gooseneck 33 is
1, the gooseneck 33 cannot be securely fixed, and since it is necessary to provide the gooseneck 33 inside the warming pot 31, the warming pot 31 must be made large.
This is because it is difficult to maintain sufficient strength due to its large size. At the same time, since the heat-retaining pot 31 is usually made of heat-resistant metal such as ductile cast iron, its large size causes a large amount of heat to be radiated to the outside, making it difficult to control the temperature of the molten metal.

Furthermore, after injecting (filling) the molten metal into the mold 32,
The plunger 35 is slid back from the lower limit position of the piston movement to its upper limit position and returned. At this time, a suction action (negative pressure phenomenon) occurs in the cylinder of the gooseneck 33, causing the nozzle 3
The molten metal remaining in 6 and the goose neck 33 is drawn back into the cylinder, and at the same time, the outside air (atmospheric air) becomes entrained gas, mixes with the molten metal, and enters the cylinder, and during the next shot, the molten metal containing the entrained gas is poured into the mold. This is a major cause of the production of cast products with many internal defects such as gas bubbles. This is because the opening position of the hole made in the wall of the cylinder to allow the molten metal in the heat-insulating pot 31 to flow into the cylinder of the gooseneck 33 shot by shot is the upper limit position of the piston movement of the plunger 35, that is, the plunger 35 When the is slid back to the upper limit position, a hole is opened and the inside of the heat insulating pot 31 and the inside of the cylinder are opened and communicated, and the molten metal in the insulating pot 31 flows into the cylinder and is poured into the cylinder.This is a communication structure between the two. Therefore, the suction action continues in the cylinder over a wide range in which the plunger 35 returns from its lower limit at the end of injection to its upper limit at the start of injection, and the wider the continued range, the stronger the suction action becomes.

Therefore, there is a hot chamber die-casting device disclosed in Japanese Patent Publication No. 1983-6113 as an injection device that solves the above-mentioned problems of the injection device.
A large-diameter hole is provided on the upper side of the long hole in the main body 33, which has a monolithic structure and has a vertical long hole (long axis) inside and is attached with a heat-resistant insulator 60 in which a heating wire 61 is embedded on the outer surface. The molten metal supply control device 4 via the pipe 26
A molten metal reservoir 43 is provided, and an injection cylinder 39 with its upper end protruding into the molten metal reservoir 43 is screwed and fixed from the bottom 73 of the pond 43 to the lower side of the elongated hole to form a cylinder. This pond 43 is provided on the protruding base wall inside the molten metal reservoir 43 of the injection cylinder 39.
Hole 4 for molten metal inflow to communicate between the inside and the inside of the cylinder
2, the plunger 4
Although the impact resistance against shocks generated during the piston movement of No. 5 and the opening/closing movement of the molds 67 and 68 has been slightly improved due to the integral structure, there is still a risk of damage due to the material of the component parts if the number of shots is increased. In addition, a continuous suction action was generated within the piston movement range in which the plunger 45 slides back from the lower limit at the end of injection to the upper limit at the start of injection.

(Problem to be Solved by the Invention) The technical problem to be solved by the present invention is that a continuous suction action does not occur in the cylinder when the plunger slides back from the lower limit at the end of injection to the upper limit at the start of injection. In addition to having a structure that connects the inflow of molten metal into the cylinder, it has high impact resistance against impact caused by piston movement of the plunger and opening/closing movement of the mold, and thermal shock resistance and heat retention against high-temperature molten metal of 600 to 1200°C. An object of the present invention is to provide an injection device for high-temperature molten metal having the following properties.

(Means for Solving the Technical Problems) The means taken by the present invention to solve the above problems is to store and install a gooseneck molded from ceramics vertically in an outer container, and to connect the outer peripheral surface and bottom surface of the gooseneck with each other. A ceramic molded storage in which a ceramic molded heat insulating material with heating wires integrally buried between the inner circumferential surface and the bottom inner surface of the outer container is closely interposed and the molten metal is stored in the upper opening of the gooseneck. The container is fixed and arranged, and a plunger is fitted in the cylinder of the gooseneck to cause piston movement by an injection cylinder, and the molten metal in the storage container is poured into the lower part of the cylinder from a desired position to the upper end within the piston movement range of the plunger. A cylinder liner made of ceramics and having a feed path for pouring hot water recessed in the direction of the cylinder on the inner circumferential surface is inserted and fixed into the cylinder, and the ceramic is made of α-Si ₃ N ₄
A solid solution with the structure Mx (Si, AI) ₁₂ (O, N) ₁₆
(In the above formula, M is Mg _, Ca, Y, etc.) "Partial stabilization" _α-
It is characterized by being an α-sialon sintered body consisting of a dense complex structure phase called a sialon region.

(Function) According to the technical means of the present invention described above, the injection cylinder causes the plunger to slide forward at its injection start rising limit, injects the molten metal into the mold into the cylinder, and the molten metal is injected into the mold. solidifies in the mold, and when the plunger slides back from the lower limit at the end of injection and returns to the upper limit at the start of injection, reaching the desired position of the piston movement range, the piston is moved by the hot water passage extending in the cylindrical direction on the inner circumferential surface of the cylinder liner. The inside of the storage container and the lower part of the cylinder are connected, and the molten metal in the storage container flows down to the lower part of the cylinder through the water supply path.
The speed of the flow is increased by the sliding retreat of the plunger which returns to the upper limit at the start of injection, and the molten metal is effectively poured into the lower part of the cylinder.

The gooseneck housed in the outer container has its outer peripheral surface and bottom surface closely attached to the inner peripheral surface and bottom inner surface of the outer container, and is a heat-insulating material made of α-sialon sintered body with a high temperature stable structure. The gooseneck is built into an integrated structure that is fixedly housed in the outer container by a material, and the cylinder liner has a hot water passage that is inserted and fixed in the cylinder of the gooseneck, and the cylinder liner is inserted and installed in the liner. The ceramics used to make the plunger and storage container contain 60vol% of α-SiAlON granular crystals and β-Si ₃ N ₄
“Partial stabilization” α where 40 vol% columnar crystals coexist
- Excellent mechanical properties such as strength, hardness, and fracture toughness in the composition range called Sialon region,
In addition, since it is an α-sialon sintered body with excellent thermal shock resistance and chemical resistance, it is expected to be resistant to shocks caused by the piston movement of the plunger and the opening and closing movements of the mold. I can,
It can be expected to have heat retention properties against high-temperature molten metals of up to 600-1200℃ and durability such as high-temperature thermal shock resistance.

(Effects of the Invention) Since the injection device of the present invention is constructed as described above, it exhibits the following effects.

Molten metal is applied to the inner circumferential surface of the cylinder liner that is inserted and fixed in the cylinder of the gooseneck, from a desired position within the range of piston movement of the plunger to its upper end, to the lower part of the cylinder that connects the inside of the storage container and the lower part of the cylinder. By providing a recessed flow path for flowing down the molten metal, the plunger reaches the middle of the piston movement from the lower limit at the end of injection within the cylinder to the upper limit at the start of injection. The inflow speed is increased by the plunger, which continues its sliding retreat back to the injection start rising limit, so the suction action that occurs inside the cylinder (at the bottom of the cylinder) when the plunger slides back. can be instantly reduced and eliminated. Therefore, there is no risk of backflow occurring when the molten metal is drawn back, or of outside air becoming entrained gas and entering the cylinder.

A storage container for storing molten metal is fixed to the upper opening of the gooseneck, and the gooseneck is stored vertically in the outer vessel, and a space between the outer circumferential surface and bottom surface of the gooseneck and the inner circumferential surface and inner surface of the bottom portion of the outer vessel is installed. A heat insulating material made of α-sialon sintered body with a heating wire embedded therein is closely interposed between the goose neck and the goose neck to securely store and fix the goose neck in the outer container. The gooseneck, the storage container, the cylinder liner with the hot water supply path inserted and fixed in the cylinder of the gooseneck, and the ceramics that make the plunger inserted and arranged in this liner are α-
Sialon granular crystals 60vol% and β-Si ₃ N ₄ columnar crystals
In the composition range called the “partially stabilized” α-SiAlON region, where 40 vol% coexists, strength,
By being an α-sialon sintered body with excellent mechanical properties such as hardness and fracture toughness, as well as excellent thermal shock resistance and chemical resistance,
The injection device has a structure that has durability such as impact resistance and thermal shock resistance, sufficient rigidity, and high heat retention.
Therefore, in combination with the durability and the heat-retaining effect of the heat-insulating material, the heat-retaining property is further improved dramatically, and the impact resistance against impact caused by the piston movement of the plunger and the opening/closing movement of the mold and the resistance to temperatures of 600 to 1200°C It can be expected to have heat retention properties for high-temperature molten metals and high-temperature thermal shock resistance.

(Example) An example of the present invention will be described based on the drawings.
The injection device A has a gooseneck 1 housed vertically in an outer container 7 and firmly fixed in the outer container 7 by a heat insulating material 5, and a storage container 2 for storing molten metal in the upper opening of the gooseneck 1. The cylinder liner 3 is inserted and fixed into the cylinder of the gooseneck 1, and the plunger 4 is inserted and fitted to move the piston by the injection cylinder 6, and is placed and arranged on the support stand 8. do.

The goose neck 1 is formed of ceramics, and a cylinder liner 3 made of ceramic and having a hot water supply passage 3a recessed in the direction of the cylinder on the inner circumferential surface is fitted over the entire length of the cylinder. It is inserted and fixed, and has good lubricity with the ceramic molded plunger 4 and is designed to have wear resistance.

The hot water supply path 3a is located at a desired position within the piston movement range of the cylinder liner 3 whose entire internal length is the piston movement range of the plunger 4, and in the drawing, is concave in the inner circumferential surface in the cylindrical direction extending from the middle part to the upper end opening side. The molten metal in the storage container 2 is poured into the lower part a of the cylinder while the plunger 4 returns from the lower limit at the end of injection to the upper limit at the start of injection.

The storage container 2 is made of ceramics and formed into a substantially bowl shape, and an opening 2a formed at the bottom of the container 2 is fitted into the upper opening of the cylinder liner 3 for direct connection, and a heating wire is attached to the outer surface of the container 2. 5'a
A heat insulating material 5' having a heat insulating material 5' provided therein is attached to keep the temperature of the molten metal stored in the storage container 2 and to reinforce the container 2. The storage container 2 is hermetically sealed with a lid plate 2b molded from ceramics to prevent oxidation of the molten metal and enhance the heat retention effect.

The heat insulating material 5 is molded from ceramics, and a heating wire 5a is integrally installed inside, and the bottom and outer peripheral surface of the goose neck 1 stored vertically within the outer container 7 and the inner surface of the outer container 7 are connected to each other. Gooseneck 1
is firmly fixed inside the outer container 7, and heated by a heating wire 5a to keep (warm) the molten metal supplied into the cylinder of the goose neck 1.

Next, the above-mentioned goose net 1, storage container 2,
The compositional structure of the ceramics constituting the lid plate 2b, cylinder liner 3, and heat insulating material 5 will be briefly described.

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

However, the ceramics used in the present invention has a dense structure (solid solution) and produces a structure that is stable at high temperatures.In other words, the ceramics used in the present invention have a dense structure (solid solution) and produce a structure that is stable at high temperatures.
It is an α-sialon sintered body in which metal atoms such as Ca, Mg, and Y are introduced into a solid solution during firing to create a high-temperature stable structure with a dense composite (solid solution) phase.

Therefore, the injection device A of the present invention is constructed into an integral structure from the gooseneck 1, cylinder liner 3, plunger 4, storage container 2, and heat insulating material 5 made of the α-sialon sintered body. It can be expected to have sufficient rigidity and durability such as impact resistance against impact caused by the piston movement of the molds 11a and 11b and the opening and closing movements of the molds 11a and 11b.
It is expected to have heat retention properties and high temperature thermal shock resistance for high temperature molten metals up to 1200℃.

Next, to explain the method of injecting molten metal into the molds 11a and 11b, the molten metal is supplied into the storage container 2 through the pipe 9 from a melting furnace (not shown) connected through the hot water supply pipe 9. flows down to the top of the cylinder and connects the top of the cylinder with the bottom of the cylinder a.
The molten metal is poured into the lower part a of the cylinder through the molten metal feed path 3a on the inner circumferential surface of the cylinder liner 3. At the time of injection,
As the plunger 4 slides forward (descends) from the injection start upper limit, it passes from the lower end of the cylinder liner 3 in the lower part of the cylinder a to the injection part 3b recessed in the cylindrical direction on the outer peripheral surface of the liner 3, and the injection From the nozzle 10 connected to the outlet of the channel 3b, the mold 1
It is injected into 1a and 11b.

As the molten metal injected into the molds 11a and 11b finishes solidifying, the plunger 4 slides back (raises) from its lower limit at the end of injection and reaches the middle of the cylinder.
, the upper part of the cylinder and the lower part a of the cylinder are connected, and the molten metal that has flowed down from the storage container 2 to the upper part of the cylinder begins to flow down to the lower part of the cylinder through the feed path 3a, and at the same time, the sliding retreat returns to the upper limit for injection start. By the continuous movement of the plunger 4, the velocity of the molten metal flowing into the cylinder lower part a is increased, and the molten metal is effectively poured into the cylinder lower part a.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view of an embodiment of the present invention installed in a die-casting machine, and FIG. 2 is a longitudinal sectional front view showing a conventional injection device. In the figure, A: injection device, 1: gooseneck, 2:
Storage container, 3: cylinder liner, 3a: hot water path, 4: plunger, 5: heat insulating material, 5a: heating wire, 6: injection cylinder, 7: outer container, a: lower part of cylinder.

Claims (1)

[Claims] 1 Heat insulation of molded ceramics in which a gooseneck molded from ceramics is housed vertically in an outer container, and heating wires are embedded integrally between the outer peripheral surface and bottom surface of the gooseneck and the inner peripheral surface and inner surface of the bottom portion of the outer container. A ceramic molded storage container for storing molten metal is fixedly arranged in the upper opening of the gooseneck, and a plunger is fitted into the cylinder of the gooseneck for piston movement by an injection cylinder. At the same time, a ceramic-molded cylinder liner is provided, which is recessed in the cylindrical direction on the inner circumferential surface of the plunger, and has a molten metal feed path recessed in the cylindrical direction on the inner circumferential surface for flowing the molten metal in the storage container into the lower part of the cylinder from a desired position within the range of piston movement of the plunger to the upper end. The above ceramic is α-Si ₃ N ₄
A solid solution with the structure Mx (Si, AI) ₁₂ (O, N) ₁₆
(In the above formula, M is Mg _, Ca, Y, etc.) "Partial stabilization" _α-
A molten metal injection device characterized by being an α-sialon sintered body consisting of a dense complex structure phase called a sialon region.