JP2001038460A - Gate valve of casting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure sealing of molten metal by preventing bite of the molten metal to a sliding part between a valve body and a plunger and preventing fracture of a packing or the like constituting the sliding part, in a gate value of a casting device which is constituted in a way that a metal supplying path of the casting device can be shut off with a plunger which can be freely slid upward/downward in the valve body. SOLUTION: A cylinder part 3C which penetrates through and slidably supports a part of a plunger 2, is covered from above with a groove part 2C of the plunger 2, and a sliding part S1 is arranged at the upper part of the molten metal M supplying path, so as to prevent bite of the molten metal into the sliding part S1. Additionally, an oil retention part L coupling the plunger 2 and the sliding parts S1, S2 of the cylinder part 3C is formed, and the oil is supplied from the oil retention part L to the sliding parts S1, S2 so as to lubricate the sliding parts S1, S2. Further, the molten metal is avoided from entering the sliding part S1, and from bite of the sliding part S1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate valve of a casting apparatus for supplying a molten metal (sometimes referred to as a molten metal) to a cavity in a mold attached to a molding apparatus. The present invention relates to a gate valve of a casting apparatus, which is configured to be able to slide up and down freely in a valve body to shut off a hot water supply path of the casting apparatus.

[0002]

2. Description of the Related Art Conventionally, molten metal held in a melting furnace, a holding furnace, or the like is supplied to a mold cavity of a mold attached to a molding apparatus (also referred to as injection or filling) to form a molded product. Casting devices for casting are generally known, and various types of casting devices are used, and the tip of a nozzle of the casting device is brought into contact with a hot water supply hole of the mold, and the casting device is cast. A method in which a nozzle hole is communicated with a hot water supply hole of a metal mold, and molten metal is supplied to a cavity portion in the metal mold and casting is performed is often used.

In general, since the nozzle is heated to a high temperature, if the tip of the nozzle is kept in contact with the hot water supply hole of the mold, the heat of the tip of the nozzle is reduced by the heat of the mold. And the temperature of the mold rises, thereby hindering cooling of the molded article in the mold. Therefore, when the molten metal is not supplied to the mold, the hot water supply hole of the mold and the nozzle tip are separated from each other to prevent the heat at the nozzle tip from being transferred to the mold. However, if the hot water supply hole of the die is separated from the nozzle tip, there is a problem that the molten metal at the nozzle tip is released to the atmosphere and oxidized.
The casting apparatus as disclosed in Japanese Patent No. 39510 uses a gate valve having a valve function as a nozzle, and closing the valve prevents the molten metal from being released to the atmosphere and being oxidized.

As the structure of the gate valve, a gate valve having a structure as shown in FIG. 4 is often used. The gate valve shown in FIG. 4 includes a valve body, a plunger, and a drive for driving the plunger. And a device,
The plunger slides up and down in the valve body by the driving device, thereby switching the nozzle hole formed in the upper end of the valve body with the tip of the plunger to a closed state or an unblocked state, The structure is such that the hot water supply path of the casting apparatus is cut off or communicated, and the hot water supply path of the casting apparatus is shut off.

[0005] In recent years, in recent years, as a core for injection molding an automobile intake manifold or the like with a resin material, casting molding of a very low melting point alloy, for example, a low melting point alloy such as a Sn-Bi alloy or the like has been proposed. In many cases, the molten metal of these low melting point alloys is very easily oxidized, so it is necessary to prevent the molten metal from being oxidized by using a gate valve.

[0006]

However, in the gate valve of the conventional structure as shown in FIG. 4, a sliding portion between the valve body and the plunger is disposed below the hot water supply path. The part has a slight clearance (sometimes referred to as a gap) for sliding between the valve body and the plunger. A gate valve having a conventional structure as shown in FIG. 4 is provided with a sealing member such as a packing on the sliding part to form a part of the sliding part in order to prevent the molten metal from leaking from the clearance, The structure is such that the molten metal is not leaked by sealing the molten metal with the sealing member disposed on the sliding portion, but the sealing member disposed on the sliding portion is gradually worn due to sliding, thereby deteriorating the sealing performance. Let it.

[0007] When the sealing property of the sealing member used for the sliding portion disposed below the molten metal supply path is reduced, the molten metal tends to move downward by its own weight, and the sealing member and the sliding portion having reduced sealing performance are not used. This causes a problem that the molten metal bites into the sliding portion. When the molten metal is caught between the sealing member and the sliding portion, the sealing member is greatly worn and damaged by the caught molten metal, and the molten metal leaks downward from the sliding portion, or This causes problems such as poor sliding. When the molten metal leaks downward from the sliding portion, the gate valve having the conventional structure as shown in FIG. 4 is configured such that the leaked molten metal adheres to a driving device or the like and solidifies and deposits. This may cause malfunction of the gate valve.

[0008] Even when the clearance for sliding the valve body and the plunger is reduced to such a degree that the molten metal cannot pass through and the molten metal is sealed, the sliding portion slides. The valve body or the plunger wears out and the clearance gradually increases. Therefore, when the sliding portion is disposed below the molten metal supply path, the molten metal tends to move downward by its own weight, easily enters the increased clearance, and causes the problem that the molten metal bites into the sliding portion. Occurs.

[0009]

In order to achieve the above object, a gate valve of a casting apparatus according to the present invention comprises: (1) a casting apparatus for feeding molten metal into a mold mounted on a molding apparatus and casting the molten metal. Wherein the gate valve includes a valve body, a plunger, and a driving device that drives the plunger, wherein the plunger is
A gate valve of a casting machine, wherein the driving device slides up and down the valve body so as to freely shut off a hot water supply path of the casting machine. The plunger includes a cylindrical portion that is slidably supported by fitting a part of the plunger, and the plunger includes a groove that is capable of fitting the cylindrical portion from above and sliding freely with the cylindrical portion. Is configured to slide up and down while the cylindrical portion is fitted in the groove portion from above.

(2) In the gate valve of the casting apparatus according to the above (1), the molten metal is a low-melting metal molten metal, and is formed by an end face of a cylindrical portion fitted in the groove and the groove. Forming an oil reservoir communicating with the plunger and the sliding portion of the cylindrical portion, and supplying oil to the plunger and the sliding portion of the cylindrical portion from the oil reservoir to lubricate the sliding portion; Further, the configuration is such that the molten metal is prevented from being caught in the sliding portion.

(3) In the gate valve of the casting apparatus according to the above (1) or (2), the valve main body and the driving device are fixed via a cooling rod, and the cooling rod is connected to the plunger. And a part thereof is slidably supported by being fitted thereinto, and a plurality of heat radiating plates are provided on the outer peripheral portion.

(4) In the gate valve of the casting apparatus according to the above (3), an oil supply hole communicating with the oil reservoir at a sliding portion between the plunger and the valve body or a sliding portion between the plunger and the cooling rod. Is arranged.

[0013]

Embodiments of the present invention (sometimes referred to as embodiments) will be described below in detail with reference to the drawings. 1 to 3 relate to an embodiment of the present invention.
2 is a cross-sectional view of a main part of the gate valve, FIG. 2 is an overall configuration diagram of the casting apparatus, and FIG. 3 is a cross-sectional view of a main part illustrating a state of lubrication of the gate valve with lubricating oil. FIG. 4 is a sectional view of a main part of a conventional gate valve.

The structure of the casting apparatus 100 using the gate valve 1 of the casting apparatus according to the present embodiment will be described below. As shown in FIG. 2, the casting apparatus 100 includes a molten metal M
Furnace 10 for storing and holding water, hot water supply pump 20 and pump switching valve 30 immersed in holding furnace 10, and molten metal M
, A gate valve 1 (which will be described later in detail), and a return line for returning the molten metal M from the gate valve 1 to the holding furnace 10. 60, a communication shut-off valve 70 for the return line immersed in the holding furnace 10, and a line heat retaining device 80.

The holding furnace 10 stores a molten metal M (in this embodiment, a Sn-Bi alloy which is a low melting point alloy, melting point of 150 ° C. to 200 ° C.) in a metal container, covers an upper opening, and stores heat. The surroundings are heated and kept warm (in the present embodiment, the temperature is raised to 200 ° C. and kept warm), and the hot water supply pump 20 is immersed in the molten metal M in the holding furnace 10 and arranged. ing. The hot water supply pump 20 has a structure in which a piston 20b is disposed slidably in a vertical direction via a servomotor 21 and a ball screw mechanism 22 in a cylindrical cylinder 20a, and a lower end surface of the cylinder 20a has The through hole 20c is formed, and the through hole 20c is connected to the pump switching valve 30. The pump switching valve 30
Is configured to switch between a port connected to the through hole 20 c and a port connected to the holding furnace 10 or a port connected to the supply pipe 40.

Here, the drive base 7 connected to the valve body 3 is configured to freely move up and down by the operation of the hydraulic cylinder 85, and the drive base 7 is freely moved up and down by the operation of the hydraulic cylinder 85. As a result, the entire gate valve 1 is freely raised or lowered, and the mold 5 attached to the molding apparatus and disposed above the gate valve 1 is formed.
It has a structure that abuts or separates from zero. Then, by bringing the gate valve 1 into contact with the mold 50, the valve head 2A, which is the nozzle tip of the casting apparatus, is brought into contact with the hot water supply hole of the mold 50, thereby forming a hot water supply path of the casting apparatus. The nozzle hole N is communicated with the hot water supply hole of the mold 50, and the hot water supply passage of the casting apparatus is communicated with the mold 50. Further, when the gate valve 1 is separated from the mold 50, the hot water supply hole of the mold 50 is separated from the valve head 2A serving as a nozzle of the casting apparatus.

Here, an opening is provided on a side surface of the valve body 3, and is connected to a supply pipe 40 and a return pipe 60 of the molten metal M via a piping block 8. The heat medium W for temperature control supplied by the temperature control device 80 (sometimes referred to as a heat medium W for temperature control) is supplied to the temperature control pipe 80a.
Is supplied to the valve body 3 via the piping block 8 and the like, and heats the valve body 3 to a desired temperature.

A communication cutoff valve 70 in the holding furnace 10 is configured to cut off communication between the return pipe 60 and a port communicating with the molten metal M in the holding furnace. When the gate valve 1 is higher than the surface of the holding furnace 10 as in the casting apparatus shown in FIG. 2, the supply of the molten metal M by the hot water supply pump 20 is stopped, and then the communication cutoff valve 70 is set to the communication state. As a result, the molten metal M by its own weight naturally falls back into the return line 60 and returns to the holding furnace 10, and when there is unsolidified metal in the mold cavity and the unsolidified metal is collected,
If the gate valve 1 is opened by lowering the plunger 2 while keeping the communication shut-off valve 70 in the communication state, the molten metal M falls by its own weight and returns naturally to the return line 60 to return to the holding furnace 10. ing.

Next, the structure of the gate valve 1 of the casting apparatus according to the present embodiment will be described in detail below. As shown in FIG. 1, the gate valve 1 of the casting apparatus according to the present embodiment includes a valve body 3, a plunger 2, and a driving device 5 for driving the plunger 2. here,
The valve body 3 includes a valve head 3A and a valve base 3B.
And a cylindrical portion 3C, and a valve base 3B
Has a cylindrical portion 3C near the center and a valve head 3A mounted thereon.

The plunger 2 comprises a plunger head 2A and a plunger rod 2B. And
The lower portion of the plunger head 2A is formed in a cylindrical shape, and a plunger rod 2B is mounted on an inner center line of the cylinder (sometimes referred to as a skirt) (in this embodiment, fixed by screwing). An annular groove 2C is formed between the plunger head 2A and the plunger rod 2B. In the present embodiment, the plunger 2 has a split structure in order to facilitate the processing of the parts. However, the plunger 2 may have an integrated structure, and the valve body 3 may have an integrated structure.

Here, as shown in FIG. 3, the valve body 3 includes a plunger rod 2B which is a part of the plunger 2.
Is slidably fitted inside the cylindrical portion 3C, which is a part of the valve body 3, so that the plunger rod 2B, which is a part of the plunger 2, is fitted through the cylindrical portion 3C. The plunger 2 is supported so as to be slidable in 3.

The groove 2C covers the cylindrical portion 3C so as to cover the cylindrical portion 3C from above, so that the cylindrical portion 3C is fitted. The groove 2C and the cylindrical portion 3C are
In S1, S2, it can slide freely.

As shown in FIGS. 1 and 3, a space R required for the plunger head 2A to slide freely is formed below the skirt portion. Here, since the molten metal M flows into the space R, the space R constitutes a part of a hot water supply path of the molten metal M.
Therefore, in the present embodiment, the sliding portion S1 is arranged above the hot water supply path of the molten metal M, and the molten metal M
Has a structure that contacts the sliding portion S1 only from below the sliding portion S1. The molten metal M in the hot water supply path has a structure that does not directly contact the sliding portion S2.

In this embodiment, as shown in FIG. 1, a plurality of rows of packings (in this embodiment, two rows of packings) are provided on a sliding portion S1 between the plunger head 2 and the outer peripheral portion of the cylindrical portion 3C.
A plurality of rows of slide rings (in the present embodiment, a plurality of rows of Teflon-based U-shaped packings) are provided on a sliding portion S2 between the plunger rod 2B and the inner peripheral surface of the cylindrical portion 3C.
2 rows of carbon-based slide rings)
The sealing performance of the sliding portion S1 is improved by a plurality of rows of packing arranged in 1, and the plunger rod 2B is guided and slid by a plurality of rows of sliding rings arranged in the sliding portion S2. Further, the slide ring used in the present embodiment is of a split type, which is a combination of two semi-annular rings and used as one annular slide ring.

In this embodiment, a U-shaped packing or a slide ring is used. However, other means, such as a combination of a gland packing and a slide bearing, are used to seal the sliding portion as described above. For example, it may be possible to improve the performance or to provide a guide function.

In this embodiment, as shown in FIG. 3, the end face of the cylindrical portion 3C fitted in the groove 2C and the groove 2C.
With C, the gap formed was filled with oil for lubrication (sometimes referred to as lubricating oil Y) to form an oil reservoir L. The oil reservoir L communicates with the sliding parts S1, S2, etc., and supplies lubricating oil to the sliding parts, thereby reducing the sliding resistance of the sliding parts and sealing the sliding parts. To improve. The slide ring used in this embodiment is of a split type, and the lubricating oil Y
Therefore, the lubricating oil Y can be supplied to the entire sliding portions S1 and S2.

The driving device 5 is fixed below the valve body 3 via a cooling rod 4 also serving as a mounting bracket for the driving device 5. The cooling rod 4 has a plunger rod 2B, which is a part of a plunger, inside. And a plurality of (two in the present embodiment) heat radiating plates 4B are provided on the outer peripheral portion while being slidably supported. Further, since the plunger rod 2B and the piston rod 5A of the driving device 5 are connected in the cooling rod 4, the driving device 5 is operated to cause the plunger rod 2B to operate.
Slides up and down freely within the valve body 3.

The heat radiating plate 4B used in this embodiment is
As shown in FIG. 1, it is a ring-shaped flat plate having two rows, but the shape of the heat radiating plate used in the present invention is not limited to this, and any shape may be provided on the cooling rod to increase the heat radiating area. For example, the block may have a plurality of grooves.

In this embodiment, as shown in FIG. 3, the cooling rod 4 is provided with an oil supply hole K1 for oil supply, and the oil supply hole K1 is provided between the plunger 2 and the cooling rod. 4, the plunger 2 communicates with the sliding portions S1, S2 of the valve body 3 and the oil reservoir L via the sliding portion.

Further, in the present embodiment, the sliding portions S1, S2 of the plunger 2 and the valve body 3 and the oil reservoir L via the sliding portion of the plunger 2 and the cooling rod 4.
The sliding portion S1 can be vacuum-sealed by packing disposed on the sliding portion S1.
1, S2, the oil reservoir L, etc., have a structure capable of sucking air to make a state close to vacuum. Therefore, after closing the valve 203 and sucking air in the sliding portions S1 and S2, the oil reservoir L, the inside of the chamber 200, and the like from the vacuum drawing hole K2 to make the state close to vacuum, the valve 20 is closed.
By opening 3, the lubricating oil Y is supplied from the lubrication hole K1, and the sliding portion and the oil reservoir L can be filled with the lubricating oil Y.

In the present embodiment, a Sn-Bi alloy, which is a low melting point alloy, is used as the molten metal M, and the valve body 3 of the gate valve 1 is heated to about 200 ° C. and held. Highly heat-resistant heat-resistant oil (heat-resistant temperature 400 ° C) that is generally used as a heat medium as the lubricating oil Y
It was used.

The gate valve 1 of the casting apparatus described above
The operation of the casting apparatus 100 according to the present embodiment using the above will be briefly described below step by step. The pump switching valve 30 is switched to close the port of the supply pipe line 40, open the port connecting the inside of the holding furnace and the through hole 20c, and then raise the piston 20b of the hot water supply pump 20 to move a prescribed amount of molten metal into the cylinder 20a. Take in M. At this time, the communication cutoff valve 70 shuts off the communication between the return pipe 60 and the holding furnace 10. Next, the hydraulic cylinder 85 is operated to move the gate valve 1 forward in the direction of the mold 50 to raise it, and the valve head, which is the tip of the gate valve 1, is pressed against the hot water supply hole of the mold to make contact with the mold. The gate valve 1 is brought into close contact with the mold 50.

The plunger 2 of the gate valve 1 is lowered, so that the nozzle hole N is not blocked by the tip of the plunger head 2A, and the gate valve 1 is opened. By switching the pump switching valve 30, the inside of the holding furnace and the through hole 20 are switched.
c, the port connecting the supply line 40 and the through hole 20c is opened, and then the piston 20 of the hot water supply pump 20 is closed.
b, and the molten metal M in the cylinder 20a is
Through the gate valve 1 to fill the mold cavity.

After maintaining the state for a certain period of time after the completion of filling, the plunger 2 of the gate valve 1 is raised, and the nozzle hole N is closed by the tip of the plunger head 2A, and the gate valve 1 is closed. State. After cooling the molten metal M in the mold 50 and solidifying it to some extent, the gate valve 1 is moved backward in the mold cavity direction and lowered, and the valve head, which is the tip of the gate valve 1, is separated from the hot water supply hole of the mold. Let it. After the molten metal M is cooled and solidified in the mold 50, it is taken out as a molded product.

In the case of the gate valve of the casting apparatus having the conventional structure, when the plunger in the valve body is moved up and down in the above steps, the molten metal flowing through the hot water supply passage in the valve body is lowered by its own weight. Try to move.
Therefore, in the case where the sealing performance of the sliding portion S1 is reduced due to a decrease in the sealing performance of the sealing member disposed on the sliding portion S1 due to abrasion or the like, the sliding portion disposed below the hot water supply passage is provided. There is a problem that the molten metal enters and bites.
However, in the gate valve 1 of the casting apparatus according to the present embodiment, the sliding portion S1 is disposed above the hot water supply path of the molten metal M. For this reason, even when the sealing performance of the sliding portion S1 is reduced, the molten metal M does not easily enter the sliding portion S1 above the hot water supply path. Therefore,
If the gate valve 1 of the casting apparatus according to the present embodiment,
It is possible to prevent the molten metal M from being caught in the sliding portion S1.

According to the present embodiment, the lubricating oil Y is filled in the oil reservoir L and the lubricating oil Y is supplied to the sliding portions S1 and S2. , Molten metal M
When the molten metal M enters the sliding portion S1 disposed above the hot water supply path and tries to bite, the molten metal M enters the sliding portion S1 by the lubricating oil Y supplied to the sliding portion S1. To prevent the molten metal M from biting into the sliding portion S1. In addition, since the low melting point alloy has a very large specific gravity with respect to the lubricating oil Y, the low melting point alloy that has entered the sliding portion S1 is also affected by the difference in specific gravity.
1 naturally descends and is discharged below the sliding portion S1.

When the plunger 2 is moved up and down while the oil reservoir L is filled with the lubricating oil Y while the cylindrical portion 3C is fitted from above in the groove 2C, the volume of the oil reservoir L changes. Therefore, it is necessary to change the amount of the lubricating oil Y filled in the oil reservoir L. In the present embodiment, the lubricating oil Y
After the filling of the oil reservoir L is completed, the valve 203 is closed, the valve 202 is opened, and the volume of the chamber 200 or the piston 200 pressing force is changed according to the change in the volume of the oil reservoir L. The amount of the lubricating oil Y can be controlled to a desired amount, and at the same time, the pressure generated in the lubricating oil Y in the oil reservoir L can be controlled and maintained at a desired pressure.

In this embodiment, the chamber 2
The pressure generated in the lubricating oil Y in the oil reservoir L can be controlled and maintained at a desired pressure by changing the piston pressing force and the like of 00, so that the pressure of the lubricating oil Y Is slightly increased, or the pressure of the molten metal M and the pressure of the lubricating oil Y are made substantially equal to each other, thereby preventing the molten metal M from entering the sliding portion S1 and causing the sliding portion S1 of the molten metal M to slide. Can be prevented from being bitten.

When the amount of heat of the valve body 3 is transmitted to the drive unit 5 and the drive unit 5 becomes high in temperature, the drive unit 5 having no heat resistance (a hydraulic cylinder in this embodiment) is activated. Failure occurs, and stable operation becomes impossible. In the present embodiment, since the valve body 3 and the driving device 5 are fixedly mounted via the cooling rod 4 provided with a plurality of heat radiating plates on the outer peripheral portion, the valve body 3 is heated to a high temperature. Also, the heat is radiated by the heat radiating plate 4B of the cooling rod 4, and the amount of heat transmitted to the driving device 5 is reduced, so that the driving device 5 can be prevented from becoming high temperature. Therefore, even if a drive device 5 having no heat resistance, such as a hydraulic cylinder, is used as a drive source of the plunger 2, stable operation can be performed.

[0040]

According to the first aspect of the present invention, the sliding portion between the valve body and the plunger is disposed above the molten metal supply passage, and the molten metal is disposed below the sliding portion with respect to the sliding portion. It has a structure that contacts only. The molten metal tends to move downward due to its own weight, but is difficult to move upward, so that the sealing performance of the sliding portion is reduced, for example, the sealing performance of the sealing member disposed on the sliding portion is reduced. Even if it does, it is difficult for the molten metal to enter the sliding portion above the hot water supply path.
Therefore, according to the first aspect of the present invention, it is possible to prevent the molten metal from being caught in the sliding portion.

According to the second aspect of the present invention, the oil reservoir is formed by the groove of the plunger and the end surface of the cylindrical portion which is a part of the valve body, and the oil reservoir is filled with lubricating oil. The lubricating oil is supplied from the part to the sliding part. The invention according to claim 2, wherein in a case where the molten metal attempts to enter a sliding portion disposed above the molten metal supply passage due to pressure or the like at the time of filling the molten metal into the mold, the oil sump is provided. The lubricating oil supplied from the portion to the sliding portion inhibits the molten metal from entering the sliding portion, thereby preventing the molten metal from biting into the sliding portion. In addition, since the low melting point alloy has a very large specific gravity with respect to the lubricating oil, the low melting point alloy that has entered the sliding portion naturally descends the sliding portion due to the difference in specific gravity, and the low melting point alloy is lower than the sliding portion. Since the molten metal is discharged downward, the molten metal is prevented from biting into the sliding portion.

According to the third aspect of the present invention, since the valve body and the driving device are fixed via a cooling rod provided with a plurality of heat radiating plates on the outer periphery, the valve body is heated to a high temperature. Also, since the heat dissipated by the cooling rod radiator plate can reduce the amount of heat transmitted to the driving device, the driving device can be prevented from becoming high temperature, and the heat resistance as a driving source for the plunger of the gate valve can be reduced. A stable operation can be performed even if a drive device having no is used.

According to a fourth aspect of the present invention, the cooling rod is provided with an oil supply hole communicating with the sliding portion between the plunger and the valve body, the sliding portion between the plunger and the cooling rod, and the oil reservoir. Thus, with a simple structure, a stable operation can be performed by supplying lubricating oil to the sliding portion and the oil reservoir.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a gate valve according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a casting device according to an embodiment of the present invention.

FIG. 3 is an explanatory cross-sectional view of a main part illustrating a state of lubrication of a gate valve according to an embodiment of the present invention with lubricating oil.

FIG. 4 is a sectional view of a main part of a conventional gate valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gate valve 2 Plunger 2A Plunger head 2B Plunger rod 2C Groove part 3 Valve body 3A Valve head 3B Valve base 3C Cylindrical part 4 Cooling rod 4B Heat sink 5 Drive unit 100 Casting unit 10 Holding furnace K1 Oil supply hole K2 Vacuum drawing hole L Oil reservoir Part M Molten N Nozzle hole R Space S1 Sliding part S2 Sliding part Y Lubricating oil

Claims (4)

[Claims] 1. A gate valve of a casting apparatus for feeding molten metal into a mold attached to a molding apparatus and casting the molten metal, the gate valve comprising: a valve body; a plunger; and a driving device for driving the plunger. Wherein the plunger slides within the valve body by the driving device to freely move up and down, thereby shutting off a hot water supply passage of the casting device. The valve body includes a cylindrical portion that slidably supports a part of the plunger by being inserted therein, and the plunger is fitted over the cylindrical portion from above and slides freely with the cylindrical portion. A gate valve for a casting apparatus, wherein the plunger slides up and down while being fitted with the cylindrical portion from above in the groove. 2. The metal melt is a metal melt having a low melting point, and an oil communicating with the plunger and a sliding portion of the cylindrical portion by an end face of the cylindrical portion fitted in the groove and the groove. Forming a reservoir, supplying oil to the sliding portion between the plunger and the cylindrical portion from the oil reservoir, thereby lubricating the sliding portion,
2. The gate valve according to claim 1, wherein the molten metal is prevented from being caught in the sliding portion. 3. The valve body and the driving device are fixedly mounted via a cooling rod. The cooling rod supports a part of the plunger therein so as to be slidably supported and has an outer periphery. 3. The gate valve according to claim 1, wherein a plurality of heat radiating plates are provided in the portion. 4. A sliding portion between the plunger and the valve body,
4. The gate valve according to claim 3, wherein an oil supply hole communicating with the oil reservoir is provided at a sliding portion between the plunger and the cooling rod.