JP2003311387A - Molten metal holding furnace for casting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molten metal holding furnace for casting which has a simple structure and can cast at a high precision while supplying the molten metal at high pressure. <P>SOLUTION: A closed pot 12 disposing a stoke 19 at the outer part, is arranged in the molten metal holding furnace 1 for casting, and a casting machine 40 is disposed above the closed pot 12 provided with a stokes 19 disposed at central part of the pot 12 so as to apply the pressure in this closed pot 12 by bringing a cavity 41 in a metallic mold into contact with the stokes. Such trouble as to bring about the damage of a furnace wall by invading the molten metal into porous part in the furnace wall refractory, is not developed. Further, since the molten metal introducing pipe for introducing to the outer part is not provided, the high pressure of ≥1.0 kg/cm<SP>2</SP>in the closed pot 21 can be impressed. Therefore, the adhesion between the molten metal and the mold surface, and the thermal conductivity, are improved by pouring the molten metal into the cavity 41 in the metallic mold from the stokes 19 while applying the high pressure to the molten metal. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal holding furnace for casting having a function of press-fitting molten metal such as aluminum or aluminum alloy into a mold cavity of a casting machine.

[0002]

2. Description of the Related Art In a casting machine for casting aluminum and aluminum alloys for automobile parts and the like, a structure in which a molten metal is filled in a mold by applying a pressure to the molten metal holding furnace It is publicly known such as fairness 2-35399. Further, in the molten metal holding furnace, a hot water supply pipe is connected to the lower part, the inlet end of the hot water supply pipe is opened into the furnace, and a closed pot communicating with the molten metal holding furnace is immersed in the molten metal holding furnace. The mold cavity arranged at a position separated from the communicating with the inside of the closed pot by the hot water pipe, the inlet end of the hot water supply pipe in the molten metal holding furnace and the inlet end of the hot water pipe in the closed pot, respectively. Japanese Patent Application Laid-Open No. 2001-276964 discloses a structure in which a predetermined amount of molten metal is supplied into a closed pot and the molten metal is supplied into a mold cavity by controlling opening / closing by an opening / closing valve. .

[0003]

However, in any of the above-mentioned configurations, the molten metal is placed in the mold cavity at 0.5-1.Okg / c.
This is related to the structure for supplying at a pressure of m2. That is, in such a structure, only the pressure within the above range can be applied to the molten metal due to the strength and the porosity of the refractory material used in the molten metal holding furnace. That is, when the pressure is increased, the molten metal enters the pores of the furnace wall refractory material and cracks or cracks occur in the refractory material. On the other hand, on the contrary, when the pressure is low, the molten metal is not sufficiently swirled in the mold cavity. In particular, the more complicated the shape of the mold, the more uneven the pressure in each part of the cavity, causing shrinkage cavities and dents in the casting,
Thinness occurs.

Further, in the molten metal holding furnace, a hot water supply pipe is connected to the lower portion, and a closed pot is provided so that the inlet end of the hot water supply pipe is opened into the holding furnace to communicate with the molten metal holding furnace. At the same time, the mold cavity arranged outside the molten metal holding furnace is communicated with the inside of the closed pot by the hot water discharge pipe, and the inlet end of the hot water supply pipe and the inlet end of the hot water discharge pipe are controlled to be opened and closed by the open / close control valves. The configuration configured as described above is disclosed in Japanese Patent Laid-Open No. 2001-27
6964. In this product, the inlet end of the hot water supply pipe is opened and the molten metal is supplied into the closed pot until the level of the molten metal is the same as that of the molten metal holding furnace. After opening the end, apply pressure to the closed pot, and after the molten metal is fed into the mold cavity outside the furnace until the molten metal falls to a predetermined molten metal level required for one tapping, The entrance end of the tap pipe is closed. And the amount of hot water discharged is adjusted by this.

In this structure, since the pressure inside the closed pot is applied, the influence of pressure on the strength and porosity of the refractory material used in the molten metal holding furnace can be avoided. By the way, in this structure, the molten metal in the closed pot is supplied to the casting machine disposed outside the molten metal holding furnace. That is, in order to prevent the inside of the hot water pipe from being oxidized, it is necessary to keep the molten metal filled. Therefore, the amount of hot water is controlled by the level of the molten metal in the closed pot. When the volume of the cavity is matched and the level of the molten metal reaches a predetermined level (predetermined amount of molten metal), the inlet end of the molten metal discharge pipe is closed, and the molten metal is always filled in the molten metal discharge pipe to prevent the return flow of molten metal. I am trying.

For this reason, this structure has the following problems. 1) This configuration is applied to a casting machine installed outside the molten metal holding furnace.
It supplies molten metal in a closed pot, and since the tapping pipe is long and the shield is limited at the joint of the pipes, it cannot be supplied at a pressure of 1.Okg / cm2 or more. That is, the present invention relates to a structure on the premise that the molten metal is supplied into the mold cavity at a pressure of 0.5 to 1.0 kg / cm 2. 2) The structure is complicated because it requires devices such as an open / close control valve for controlling the opening / closing of the inlet end of the hot water outlet pipe and a level sensor. 3) It is necessary to dispose a heater around the long hot water pipe that reaches the mold cavity so that the molten metal in the hot water pipe that is drawn out of the road is not cooled and solidified.

That is, the above-mentioned JP 2001-2769 A.
The configuration in which the closed pot according to 64 is arranged in the furnace is for controlling the amount of hot water discharged to the mold cavity arranged outside the furnace, is not suitable for high-pressure hot water supply, and has a complicated structure. It will be a big deal.

It is an object of the present invention to provide a molten metal holding furnace for casting which has a simple structure and which can supply molten metal at a high pressure to perform highly accurate casting.

[0009]

The invention according to claim 1 is
A molten metal inlet is formed in the lower portion, a closed pot is provided in the furnace so that the molten metal inlet is located below the molten metal surface, a casting machine is provided directly above the closed pot, and a closed pot is provided. Liquid-tightly held, the Stokes, whose upper end communicates with the mold cavity and whose lower end communicates with the inside of the closed pot, the gas supply path for controlling the supply of pressurized gas to the closed pot, and the melt inlet. An open / close control device for opening and closing is provided, and when tapping into the mold cavity, the open / close control device is driven so as to close the molten metal inlet, the gas supply path is opened, and pressurized gas is fed into the closed pot. The molten metal holding furnace for casting is characterized by being supplied.

In such a structure, after the molten metal inlet is opened and the molten metal in the hot water supply chamber is introduced into the closed pot and the molten metal inlet is closed, it is difficult to react with the nitrogen gas or the metal melt such as dry air. The molten metal is injected into the mold cavity from the Stokes in the closed pot by sending an inert pressurized gas into the closed pot and applying a high pressure to the surface of the melt. When the molten metal solidifies in the mold cavity, the pressure application by the pressurized gas is released, and the molten metal inlet is opened. As a result, the molten metal remaining in the Stokes drops, and the molten metal further flows into the closed pot to raise the level of the molten metal.

Further, in such a structure, pressure is applied only to the inside of the closed pot, and the tapping pipe is not drawn out of the closed pot, and since there is no connecting part of the pipe, it is 1.Okg / cm2. The above high voltage can be applied. Therefore, the molten metal can be smoothly flown into the cavity of the casting machine, the adhesion between the molten metal and the casting machine is improved, the casting surface is improved, and the casting product is dense, has high strength, and has no cavities. Obtainable.

Further, since it suffices to simply apply the pressure to the closed pot, it is not necessary to control the amount of hot water discharged, and the control mechanism becomes simple.

The opening / closing control device for opening / closing the molten metal inlet comprises a valve for opening / closing the molten metal inlet, a drive device for converting the valve between an open position and a closed position, and a state in which the molten metal inlet is closed. It can be configured with a valve rotating mechanism that rotates the valve. In this case, the valve may be provided with a rotation closing mechanism that rotates with the molten metal inlet closed, and the molten metal solidified in the molten metal inlet is removed by the rotation of this valve. As a result, the adhesion with the peripheral edge of the valve molten metal intake is improved, and the shielding property in the closed pot is improved. Therefore, even if a high pressure is applied to the closed pot, the molten metal does not leak from the closed pot, and the opening / closing mechanism is optimal for high pressure casting.

[0014]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIGS. 1, 2 and 4, a molten metal holding furnace 1 for casting according to the present invention includes a holding chamber 2 and a holding chamber 2.
It is composed of a hot water supply room 3 which communicates with.

A bath cover 4 is provided at the upper end of the holding chamber 2 and is opened / closed by a lid opening / closing device 5. Then, the bath cover 4 is opened almost regularly, and the melt is poured into the holding chamber 2 from a separate melting furnace (not shown) to add the melt. Near the bottom of the holding chamber 2, the required number of heaters 6
Is attached to keep the molten metal at a predetermined temperature at all times. The holding chamber 2 may be divided into a hot water supply dust removing chamber and a holding temperature control chamber by the filter 10 or the like.

A molten metal cutoff valve 7 is provided in the holding chamber 2, and an amount of molten metal required for casting is sent from the holding chamber 2 to the hot water supply chamber 3 by opening / closing an opening 8 between the molten metal supply valve 3 and the hot water supply chamber 3. There is. The melt shutoff valve 7 has a structure in which a die is attached to the lower portion of the shaft, is connected to a cylinder 9 attached to the upper portion, and is driven by the cylinder 9 to move up and down to open and close the opening 8.

A heater 11 is provided near the bottom of the hot water supply chamber 3 to keep the molten metal at a temperature suitable for casting. The present invention has a main part in which a closed pot 12 for holding a straight tubular Stokes 19 in the central portion of the hot water supply chamber 3 is arranged so that its lower portion is immersed below the surface of the molten metal. The main part of the present invention will be described below.

Here, the straight tubular Stokes 19 is held in a liquid-tight manner on the closed pot 12, and has an upper end communicating with the mold cavity 41 and a lower end communicating with the inside of the closed pot 12. That is, on the closed pot 12, a casting machine 40 having an upper mold S1 and a lower mold S2 and forming a mold cavity 41 between them is arranged. The connection pipe 42 communicating with the mold cavity 41 is connected to the upper end of the Stokes 19.

Further, the closed pot 12 has an internal capacity of 10 kg / c.
It is made of a ceramic material that does not break even when a pressure of about m2 is applied and the molten metal does not penetrate into the material of the pot. A molten metal inlet 13 is formed in the lower portion of the closed pot 12, and the molten metal is introduced from the hot water supply chamber 3 into the closed pot 12 through the molten metal inlet 13 in an amount required for almost one casting. .

The molten metal intake 13 is controlled to be opened / closed by an opening / closing control device shown enlarged in FIG. Here, the molten metal inlet 13 is opened and closed by a rod-shaped valve 14 driven forward and backward by driving a cylinder 15. More specifically, the arm 16 rotatably supported by the bearing 16a at the center thereof has the rod 15a of the cylinder 15 pivotally supported at one end thereof, and the rotation holding portion 16b provided at the other end of the arm 16. The upper end of the rod-shaped valve 14 is rotatably held. The rod-shaped valve 14 is formed on a lid 20 that shields the hot water supply chamber 3, and is inserted into a guide 22 that produces a guiding action in an up-down direction in an inclined manner. Further, a spherical end surface 14a is formed at the lower end thereof. When the rod 15a of the cylinder 15 is driven to advance, the bearing 16a
The arm 16 tilts in the clockwise direction in the figure around the center, and the rod-shaped valve 14 moves downward along the guide 22 accordingly, and the molten metal intake 13 is blocked by the tip thereof. The molten metal inlet 13 is also spherically processed, so that the spherical end surface 14a makes uniform surface contact with the molten metal inlet 13. Similarly, when the rod 15a of the cylinder 15 is driven to retract, the arm 16 tilts counterclockwise, the rod-shaped valve 14 moves upward, and the molten metal intake 13 is opened. Thus, the opening / closing of the molten metal inlet 13 is controlled by controlling the cylinder 15, which constitutes an opening / closing controller. In such a structure, the closed pot 12 does not have a low pressure of 0.5 to 1.0 kg / cm2 as in the conventional case, but the above-mentioned 10 kg / cm2 (as an applicable range, 1.0 kg / cm2).
A high voltage of about / cm2 to 11 kg / cm2) is applied. Therefore, a pressure contact force capable of blocking the molten metal intake 13 against the pressure is required.

In order to completely seal the melt inlet 13 with the valve 14, the valve tip is pressed against the melt inlet 13, and then the valve 14 is rotated and tightened by the rotating mechanism 17. As shown in an enlarged view in FIG. 3, the rotating mechanism 17 has a structure in which the upper end of the rod-shaped valve 14 is attached to the arm 1.
6 is rotatably supported in a concave groove of a rotation holding portion 16b provided at the other end of 6, and the rod 24a of the rotation cylinder 24 is linked to the rod-shaped valve 14 via a link 26 in the tangential direction thereof. The rod-shaped valve 14 is reciprocally rotated by driving the rotating cylinder 24 forward and backward. Incidentally, in order to make the operation of such a mechanism smooth, a play is provided in each of the connecting portions. Thus, with the tip of the rod-shaped valve 14 in close contact with the inner peripheral edge of the molten metal inlet 13, the rod-shaped valve 14 is rotated by the drive of the rotating cylinder 24 so that the rod-shaped valve 14 comes into close contact with the molten metal inlet 13. As a result, the molten metal intake port 13 is sealed, and the shielding property inside the sealed pot 12 is improved. Therefore, as described above, even if a high pressure is applied to the closed pot 12, the molten metal does not leak from the closed pot 12.

The closed pot 12 has its opening shielded by the housing 30, and the housing 30 holds the upper end of the straight Stokes 19 in a liquid-tight manner so that the lower end of the Stokes 19 is below the inside of the closed pot 12. It is open to. A heater 31 for heating the Stokes 19 is held by the housing 30. In addition, this heater 3
1 is a simple structure because the heat retention length is short and the ambient atmosphere is high compared to the structure in which the molten metal from the closed pot is supplied to the mold cavity of the casting machine outside the molten metal holding furnace by the tapping pipe. Therefore, there is an excellent advantage that the temperature can be controlled easily. The heater may be omitted depending on the case.

A gas supply path 18 is connected above the closed pot 12 and the molten metal inlet 13 is closed by a rod-shaped valve 14 during casting at a pressure of 10 kg / cm2.
A pressurized gas made of an inert gas such as nitrogen or dry air is sent to pressurize the molten metal surface. When the molten metal is pressurized, the molten metal is injected from the lower end opening of the Stokes 19 into the mold cavity 41 formed between the upper mold S1 and the lower mold S2 installed above the closed pot 12.

Next, an operation example of the molten metal holding furnace for casting 1 according to the present invention will be described with reference to the drawings. When the molten metal is carried to the holding furnace 1 by a ladle or the like, the lid opening / closing device 5 is operated to open the molten metal lid 4, and after pouring the molten metal into the holding chamber 2,
Close the bath cover 4 again. Then, the molten metal is uniformly heated by the heater 6, and the uneven temperature is eliminated. The molten metal cutoff valve 7 normally closes the opening 8. However, when the casting work in progress is completed, the cylinder 9 is operated to raise the molten metal cutoff valve 7, and the opening 8 is opened so that only the amount necessary for the next casting is performed. Move the molten metal to the hot water supply room 3. When a level sensor (not shown) or the like detects that a certain amount of molten metal has moved to the hot water supply chamber 3, the molten metal shutoff valve 7 is lowered and the opening 8 is closed.

With the above-described structure, the molten metal of a constant level is always stored in the hot water supply chamber 3. When starting the casting of the molds S1 and S2 into the mold cavity 41, first, the cylinder 15 is operated to raise the valve 14 and open the molten metal inlet 13. As a result, the molten metal enters the closed pot 12 from the hot water supply chamber 3 until it becomes equal to the level of the molten metal in the hot water supply chamber 3, and the closed pot 12 is replenished with the molten metal required for at least one casting. In this case, the molten metal may be forcibly sucked into the closed pot 12 by using a suction pump (not shown) or the like. When the amount of molten metal required for tapping enters the closed pot 12, the cylinder 15 is activated,
The rod-shaped valve 14 is lowered via the arm 16 and pressed against the molten metal intake 13 to be in a closed state. In order to complete the sealed state of the molten metal inlet 13, the rod-shaped valve 14 is then rotated by the rotating mechanism 17 to improve the adhesion.

Next, an inert gas is sent into the closed pot 12 through the gas supply passage 18 by a pressure pump, and 10
A pressure of about kg / cm2 is applied to the surface of the melt. Nitrogen or dry air is used as the inert gas. By this pressurization, the molten metal flows into the mold cavity 41 composed of the upper mold S1 and the lower mold S2 via the Stokes 19, and casting is performed. During casting, a constant pressure is continuously applied to the closed pot 12.
At this time, the heater 31 heats the Stokes 19,
Its solidification is prevented. When the casting operation is completed, the inert gas is discharged from the gas supply passage 18 to open the pressure in the closed pot 12. As a result, the molten metal remaining in the Stokes 19 will flow down. Then, the valve 14 is again separated from the molten metal intake 13, and the molten metal required for the next time is introduced into the closed pot 12. The casting operation is continued while repeating the above operation.

In the casting operation, the ceramic closed pot 12 is provided and the pressure is applied to the closed pot 12. Therefore, the molten metal does not enter the pores of the furnace wall refractory material due to the pressure. Absent. Moreover, it does not pull out the tapping pipe to the outside of the closed pot, because there is no connecting part of the pipe,
A high voltage of 1.0 kg / cm2 to 11 kg / cm2 or more can be applied. Therefore, it is possible to flow the metal melt from the Stokes into the mold cavity 41 while applying a high pressure, and maintain the pressing force state at a high pressure. As a result, the adhesion between the melt and the inner surface of the mold cavity 41 is improved, and the space between them is improved. The thermal conductivity is improved and the solidification of the molten metal in the mold cavity 41 can be properly controlled. Then, the minute shrinkage cavities generated in the surface layer of the casting surface are improved. Also, because the pushing power is increased,
Shrinkage cavities due to insufficient supply of molten metal can also be eliminated, and strength is also improved.

[0028]

As described above, according to the present invention, the furnace is provided with the closed pot in which the Stokes is arranged, the casting machine is arranged on the closed pot, and the mold cavity and the Stokes are arranged. The pressure is applied to the closed pot by connecting with, and the molten metal is drawn out without the risk of damage to the furnace wall by entering the pores of the furnace wall refractory material. Since it does not have a tap pipe, it is possible to apply a high pressure of 1.0 kg / cm2 or more in the closed pot. Therefore, by flowing the metal melt from Stokes into the mold cavity while applying a high pressure, the adhesion between the melt and the mold surface is improved and the thermal conductivity is improved. Further, it is possible to perform highly accurate casting with inexpensive equipment cost without changing or complicating the furnace wall structure of the holding furnace. Furthermore, devices such as an on-off control valve that controls the opening and closing of the inlet end of the hot water pipe are not required,
In addition, the temperature control inside the tap pipe that is drawn out of the furnace is not required, and the equipment is simple and inexpensive.

Here, the opening / closing control device for opening / closing the molten metal inlet is provided with a valve for opening / closing the molten metal inlet, and a valve rotating mechanism for rotating with the molten metal inlet closed. And the periphery of the molten metal intake are in close contact,
The shut-off property in the closed pot is improved, and even if a high pressure is applied to the closed pot, the molten metal does not leak from the closed pot, and the opening / closing mechanism is optimal for high pressure casting.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a molten metal holding furnace for casting 1 according to an embodiment of the present invention.

FIG. 2 is a vertical sectional side view of a hot water supply chamber 3.

FIG. 3 is an enlarged vertical side view of a main part.

FIG. 4 is a plan view of a molten metal holding furnace for casting 1.

[Explanation of symbols]

1 Molten metal holding furnace for casting 2 holding room 3 hot water supply room 12 closed pot 13 intake 14 valves 15 cylinders 18 gas supply channels 19 Stokes 40 casting machine 41 mold cavity

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Haruyuki Sakabe             Chuo Seiki Co., Ltd. 2-2 Daitocho, Anjo City, Aichi Prefecture             Inside the company (72) Inventor Masamichi Kondo             Chuo Seiki Co., Ltd. 2-2 Daitocho, Anjo City, Aichi Prefecture             Inside the company (72) Inventor Shunji Mochizuki             7-14 Tsurumachi, Amagasaki City, Hyogo Prefecture             In the nets (72) Inventor Koichi Murakami             7-14 Tsurumachi, Amagasaki City, Hyogo Prefecture             In the nets

Claims (2)

[Claims] 1. A closed pot having a molten metal inlet formed in a lower portion thereof, the closed pot being arranged in the furnace so that the molten metal inlet is located below the surface of the molten metal, and a casting machine arranged directly above the closed pot. A Stokes liquid-tightly held on the sealed pot, the upper end of which communicates with the mold cavity and the lower end of which communicates with the inside of the sealed pot; and a gas supply path for controlling the supply of pressurized gas to the sealed pot. , An opening / closing control device for opening / closing the molten metal inlet, and when the molten metal is discharged into the mold cavity, the opening / closing control device is driven so as to close the molten metal inlet, the gas supply path is opened, and the inside of the closed pot is closed. A molten metal holding furnace for casting, characterized in that a pressurized gas is supplied to the furnace. 2. A valve for opening and closing the melt inlet, a valve for opening and closing the melt inlet, a drive device for converting the valve between an open position and a closed position, and a valve with the melt inlet closed. The molten metal holding furnace for casting according to claim 1, further comprising a valve rotating mechanism for rotating the.