JP2000225454A - Molten metal feeding apparatus for die casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a molten metal from touching air when the molten metal is fed into a die casting machine without using a molten metal feeding pipe, and to adjust molten metal feeding quantity highly precisely. SOLUTION: A molten metal feeding pot 3 is arranged in the state of being dipped into the molten metal 2 in a melting pot 1. In the molten metal feeding pot 3, a charge hole 7 for charging the molten metal 2 in the melting pot 1 into the inner part is provided, and the upper space part of the pot 3 is filled with inert gas. A seal valve 5 closes the charge hole 7 by being moved from the upper part to the lower part in the molten metal supplying pot 3, and pushes up the surface of the molten metal 2 in the molten metal feeding pot to the detecting height of a molten metal surface sensor 9. In this state, the surface of the molten metal 2 is pushed up to a prescribed depth by pushing a float 6 into the molten metal 2 in the molten metal feeding pot 3, then the molten metal 2 is discharged from a molten metal feeding hole 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot water supply apparatus for die casting for supplying molten metal to a sleeve connected to a mold of a cold chamber die casting machine.

[0002]

2. Description of the Related Art Die casting is for mass-producing high-precision castings with high precision by injecting a molten metal (molten alloy) into a precision mold at a high temperature. Currently, there are two types of die casting machines: hot chamber die casting machines and cold chamber die casting machines.

FIG. 4 is a view showing a hot chamber die casting machine. In FIG. 4, 1 is a melting pot, 2 is molten metal, 12 is a sleeve, 13 is a plunger, 1
4 is an inlet, 15 is a gooseneck, 16 is a nozzle, 17
Is a fixed mold, 18 is a movable mold, 19 is a slide core, and 20 is a cavity.

In a hot chamber die casting machine, a molten metal 2 is put into a melting pot 1 placed in a furnace, and a plunger 13 is moved from the uppermost part of a sleeve 12 in a gooseneck 15 shown in FIG. As shown in b), the molten metal 2 is pushed down while applying pressure at a high speed. as a result,
The molten metal 2 is pressed through a gooseneck 15 and a nozzle 16 into a cavity 20 formed by a fixed die 17, a movable die 18 and a slide core 19.

As described above, the hot-chamber die-casting machine has this name because the gooseneck 15 serving as the pressurizing chamber is immersed in the molten metal 2 and is heated, so that it is necessary to supply hot water to the pressurizing chamber every cycle. Because there is no, speedy production is possible. Therefore, a hot chamber die casting machine is used for a metal having a relatively low melting point, such as a zinc alloy, a lead alloy, and a tin alloy. In addition, this die casting machine can be used without exposing the molten metal 2 to air, and is therefore used for a magnesium alloy that is easily oxidized.

FIG. 5 is a view showing a cold chamber die casting machine. In FIG. 5, 10 is a sleeve, 2
Reference numeral 1 denotes a plunger, and the same or equivalent members as those described in FIG.

In the cold chamber die casting machine, a holding furnace is placed near the die casting machine, and the molten metal 2 kept in the furnace is scooped or the sleeve 10 is heated by an automatic water heater.
(FIG. 5 (a)). Thereafter, the molten metal 2 is fixed by the plunger 21 to the fixed mold 17, the movable mold 18 and the slide core 19.
Is press-fitted into the cavity 20 formed in (1) to obtain a die-cast product (FIG. 5 (b)). Therefore, the casting cycle time is longer than that of the hot chamber die casting machine, but a high melting point alloy such as an aluminum alloy or a copper alloy can be cast.

[0008] Such a cold-chamber die-casting machine is suitable for die-casting of large-sized products. Recently, large-sized products have been used for die-casting of magnesium alloys. In this case, since the magnesium alloy is easily oxidized, the molten metal 2 is transferred to the sleeve 11.
It is difficult to use a ladle or an automatic hot-water supply device to supply the molten metal 2 kept in the furnace in the same manner as in the related art. Therefore, a hot water supply system has been developed for the magnesium alloy that can supply hot water to the sleeve 10 as little as possible with air.

FIG. 6 is a diagram showing a hot water supply system for a magnesium alloy. In FIG. 6, 8 is a flux, 22
Is a melting furnace, 23 is a holding furnace, 24 is an ingot, 25 is a lid, 26 is a transfer pipe, 27 is a valve, 28 is a hot water supply pipe, 29 is a hot water supply port, and 30 is a heater power supply.

A layer of flux 8 is formed on the surface of the molten metal 2 contained in the melting furnace 22 and the holding furnace 23 so that the molten metal 2 does not come into contact with air. Also,
A transfer pipe 26 is provided between the melting furnace 22 and the holding furnace 23, and a hot water supply pipe 28 having a hot water supply port 29 at the other end is provided from the holding furnace 23 via a valve 27. The transfer pipe 26 and the hot water supply pipe 28 are provided with a heater, and power is supplied from the heater power supply 30 to always heat the transfer pipe 26 and the hot water supply pipe 28. Is always filled with the molten metal 2.

The lid 25 is opened and the ingot 24 is put into the melting furnace 22 to be melted. The alloy melted in the melting furnace 22 is transferred to the holding furnace 23 through the transfer pipe 26 according to the siphon principle and kept warm. Melt 2 in sleeve 10
When hot water is supplied, when the valve 27 is opened at a predetermined interval, the hot water is supplied through a hot water supply pipe 28 according to the siphon principle.
Molten metal 2 flows from holding furnace 23 to hot water supply port 29.

If this hot water supply apparatus is used, the molten metal 2 is supplied to the sleeve 10 with almost no contact with air. Therefore, it can be used without problem for die casting of a magnesium alloy which is easily oxidized.

[0013]

However, among the above-mentioned conventional die casting machines, the hot chamber die casting machine as shown in FIG. 4 pushes down the plunger 13 in the gooseneck 15 placed in the high-temperature molten metal 2. Due to the necessity, the plunger 13 is easily worn and cannot be pushed down at a very high speed. Further, since the gooseneck 15 is thermally deformed, the sleeve 12 inside the gooseneck 15 is deformed.
Diameter cannot be increased. Therefore, there is a problem that it is not suitable for manufacturing a large product.

On the other hand, the cold chamber die casting machine can cope with the manufacture of large products, but the hot water supply system as shown in FIG. 6, which is used when the magnesium alloy is die cast by the cold chamber die casting machine, has a transfer pipe. A pipe such as 26 or a hot water supply pipe 28 is required. Therefore, there is a possibility that the pipe may be clogged, and if the pipe is clogged, the pipe must be replaced. In addition, the amount of hot water supplied to the sleeve 10 by the molten metal 2 is controlled by the opening and closing time of the valve 27, and there is a problem that the accuracy of the hot water supply is inferior.

The present invention solves such a problem, and supplies hot water to the sleeve of the cold chamber die casting machine by minimizing the contact of the molten metal with air without using a hot water supply pipe and at the same time accurately supplying hot water. It is intended to be able to adjust the amount.

[0016]

According to a first aspect of the present invention, there is provided a die casting hot water supply apparatus, comprising: a melting pot in which a molten alloy is charged; and a immersion state in the melting pot. A hot water supply pot, which has an inlet for introducing the molten metal in the melting pot into the inside, and is filled with an inert gas in an upper space portion, a seal valve for closing the inlet, and the seal valve is an inlet. And a float that is pushed into the molten metal in the hot water supply pot to push up the level of the molten metal, and a hot water supply port that leads the molten metal pushed up by the float to the outside. In this manner, hot water can be supplied to the sleeve of the cold chamber die casting machine without using a hot water supply pipe and minimizing the contact of the molten metal with air.

The hot water supply device for die casting according to a second aspect of the present invention includes a hot water level sensor for detecting that a hot water level inside the hot water supply pot has reached a predetermined height, and the seal valve is provided in the hot water supply pot. To move down from above to close the inlet, and to push up the level of the molten metal in the hot water supply pot to the detection height of the level sensor, in the state when the level sensor detects the level The float is pushed into the molten metal in the hot water supply pot to a predetermined depth to push up the surface of the molten metal. In this way, the amount of hot water supply can be adjusted with high accuracy.

Further, the hot water supply apparatus for die casting according to the third aspect is characterized in that a portion of the hot water supply pot that is not immersed in the molten metal is heated by a heating means.
With this configuration, it is possible to prevent a decrease in the temperature of the molten metal flowing out of the hot water supply port, to maintain high fluidity of the molten metal, and to prevent the hot water supply port from being clogged.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a melting pot of a holding furnace or a melting and holding furnace which also serves as a melting furnace and a holding furnace, 2 denotes a molten magnesium alloy, 3 denotes a hot water supply pot, 4
Is a hot water supply port, 5 is a seal valve, 6 is a float, 7 is an inlet, 8 is a flux, 9 is a level sensor, 10 is a sleeve, and 11 is a pouring port.

The hot water supply pot 3 can be made of, for example, cast iron, and is provided in a state of being immersed in the molten metal 2 in the melting pot 1, for introducing the molten metal 2 in the melting pot 1. Inlet 7 and molten metal 2 inside
Water supply port 4 for pouring water into pouring port 11 of sleeve 10
It has. A cylindrical portion having an open bottom is formed in a portion where the inlet 7 is provided. Is provided. The seal valve 5 can be formed of, for example, cast iron.

In the hot water supply pot 3, there are provided a float 6 which moves upward and pushes away the molten metal 2, and a molten metal surface sensor 9 for detecting that the molten metal 2 has reached a predetermined height. Is provided. The seal valve 5 can be formed of, for example, cast iron, and an appropriate sensor that can detect the molten metal level can be used as the molten metal level sensor 9. For example, it is possible to use a conductive sensor which has two electrodes and detects when the level of the molten metal 2 reaches a predetermined level by conducting between the electrodes when the molten metal 2 comes into contact with the molten metal 2. Alternatively, an appropriate sensor such as a temperature sensor that detects that the level of the molten metal 2 has reached a predetermined level by detecting a temperature change when the molten metal 2 comes into contact with the molten metal 2 can be used. However, it is desirable to use a conductive sensor in that the sensor can be detected without time delay when the molten metal level reaches a predetermined level. It is desirable that the level sensor 9 be moved upward after detecting the level to prevent the level sensor 9 from entering the molten metal 2.

The molten metal 2 in the melting pot 1 is prevented from coming into contact with air by the layer of the flux 8. The upper space of the hot water supply pot 3 containing the seal valve 5 and the float 6 is covered with a cover in a hermetically sealed state, and an inert gas such as argon gas, nitrogen gas, etc. So as to flow out of the hot water supply port 4 so that the upper space of the hot water supply pot 3 is always filled with inert gas so that the molten metal 2 does not touch the air.

As shown in FIG. 1, when the seal valve 5 and the float 6 are raised above the surface of the molten metal 2, the inside of the hot water supply pot 3 communicates with the melting pot 1 through the inlet 7. The level of the hot water in the hot water supply pot 3 is equal to the level of the hot water in the melting pot 1. From this state, the seal valve 5 is moved downward.

When the seal valve 5 descends below the inlet 7, the inlet 7 is closed by the seal valve 5. Thereafter, when the seal valve 5 is further lowered, the molten metal 2 in the hot water supply pot 3 is pushed away by the seal valve 5, and the molten metal surface rises, and as shown in FIG. The sensor 9 detects this, and outputs a detection signal to a control device (not shown). As a result, the control device stops the lowering of the seal valve 5.

Then, as shown in FIG. 3, with the seal valve 5 fixed at that position, the molten metal level sensor 9 is pulled up by a lifting device, and then the float 6 is lowered to a predetermined position. As a result, the molten metal 2 in the hot water supply pot 3 is pushed up by the float 6, flows out toward the hot water supply port 4, and is poured into the sleeve 10 from the pouring port 11. At that time, the water level before lowering the float 6
The level of the molten metal 2 injected into the sleeve 10 is always constant because the level of the float 6 is constantly controlled by the level sensor 9 and the stroke of the lowering of the float 6 is constantly controlled.

When the hot water supply is completed, the float 6 and the seal valve 5 are pulled up again. As a result, the molten metal 2 in the melting pot 1 flows into the hot water supply pot 3 from the inlet 7, and the level of the molten metal 2 in the hot water supply pot 3 rises again to the same level as the level of the molten metal in the melting pot 1. I do. The level of the molten metal at that time is reduced by the amount used, but also in the next step, the level of the molten metal in the hot water supply pot 3 before the float 6 is lowered is made constant by the level sensor 9. Therefore, the hot water supply amount becomes the same amount as the previous time.

A heater is provided inside the seal valve 5 and the float 6 so as to prevent the temperature of the molten metal 2 in the hot water supply pot 3 from being lowered and the fluidity from being deteriorated. Also,
A heating means such as a heater is also provided in a portion of the hot water supply pot 3 which is above the molten metal 2 so that the temperature of the molten metal 2 flowing out of the hot water supply port 4 is lowered, the fluidity is deteriorated, and the hot water supply path is not blocked. I have to.

Also, in the above embodiment, the case where the hot water supply device for die casting of the present invention is used for die casting of a magnesium alloy has been described. However, the hot water supply device for die casting of the present invention is applicable to other metals such as aluminum alloys and zinc alloys. Can also be used for die casting. However, when used for die-casting of aluminum alloy, cast iron cannot be used for hot water supply pot 3, seal valve 5, float 6, etc., because aluminum alloy has a property of corroding iron. It is necessary to form with.

[0029]

Since the present invention is configured as described above, it has the following effects. That is, a hot water supply pot having an inlet for introducing the molten metal therein and filled with an inert gas in the upper space portion is disposed in a state of being immersed in the molten metal of the melting pot, and the molten metal is supplied from the hot water supply pot. In this case, after the inlet was closed with a seal valve, a float was pushed into the molten metal in the hot water supply pot to push up the molten metal and to lead the molten metal to the outside from the hot water supply port. As a result, without using a hot water supply pipe,
Hot water can be supplied to the sleeve of the cold chamber die casting machine while minimizing the contact of the molten metal with the air.

The hot water supply device for die casting according to a second aspect of the present invention includes a hot water level sensor for detecting that the hot water level inside the hot water supply pot has reached a predetermined height, and the seal valve includes:
While moving the inside of the hot water pot from top to bottom to close the inlet, the level of the molten metal in the hot water pot was pushed up to the detection height of the level sensor, and the level sensor detected the level. In this state, the float is pushed into the molten metal in the hot water supply pot to a predetermined depth to push up the surface of the molten metal. As a result, the hot water supply amount can be adjusted with high accuracy.

In the third aspect of the present invention, since the portion of the hot water supply pot that is not immersed in the molten metal is heated by the heating means, the temperature of the molten metal flowing out of the hot water supply port can be prevented from lowering. As a result, the flowability of the molten metal can be kept high, and clogging of the hot water supply port can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing a state where a seal valve is pushed down.

FIG. 3 is a diagram showing a state in which hot water is supplied by pushing down a float.

FIG. 4 is a view showing a hot chamber die casting machine.

FIG. 5 is a view showing a cold chamber die casting machine.

FIG. 6 is a diagram showing a hot water supply system for a magnesium alloy.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Melting pot 2 ... Molten metal 3 ... Hot water supply pot 4 ... Hot water supply port 5 ... Seal valve 6 ... Float 7 ... Introduction port 8 ... Flux 9 ... Metal level sensor 10 ... Sleeve 11 ... Pouring port

Claims (3)

[Claims] 1. An upper space portion, comprising: a melting pot into which a molten metal of an alloy is to be placed; and an inlet disposed to be immersed in the molten metal of the melting pot to introduce the molten metal in the melting pot into the interior. Hot water supply pot filled with an inert gas, a seal valve for closing the inlet, and a state in which the seal valve closes the inlet, is pushed into the molten metal in the hot water supply pot to push up the surface of the molten metal. A hot water supply device for die-casting, comprising: a float; and a hot water supply port for drawing out the molten metal pushed up by the float to the outside. 2. A hot water level sensor for detecting that a hot water level inside the hot water supply pot has reached a predetermined height, wherein the seal valve moves down from the top in the hot water supply pot to close the inlet. While closing, to raise the level of the molten metal in the hot water supply pot to the detection height of the level sensor, in the state when the level sensor detects the level, the float,
A hot water supply device for die casting, wherein the molten metal is pushed into a molten metal in a hot water supply pot to a predetermined depth to push up the surface of the molten metal. 3. The hot water supply apparatus for die casting according to claim 1, wherein a portion of the hot water supply pot that is not immersed in the molten metal is heated by a heating means.