JP2606053B2 - Casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention covers a cylindrical gate member having a ceiling portion over an opening of a molten metal passage formed in a mold to close the molten metal passage and store molten metal inside the gate member. The present invention relates to a casting device having a structure.

[0002]

2. Description of the Related Art A related casting apparatus (suction casting apparatus) has been proposed in the specification and drawings of Japanese Patent Application No. 306999/1991 filed by the present applicant. As shown in FIG. 3, the suction casting apparatus includes a cylindrical gate piston 7 having an upper plate 7u. The gate piston 7 is slidably accommodated in a through hole 2a formed in the upper die 2 of the mold in a vertical direction. Then, with the gate piston 7 lowered to the lower limit position, the front end surface 7s abuts on the upper surface 4j of the lower die 4 of the mold, and is put on the upper end of the molten metal passage 8a formed in the lower die 4. As a result, the space (the molten metal reservoir 7r) formed inside the gate piston 7 is connected to the molten metal passage 8a to close the molten metal passage 8a, and the outer surface of the gate piston 7 is formed in the mold. The gate 6a of the cavity 6 thus closed is closed.

[0003] At the center of the upper plate 7u of the gate piston 7, a permeable sintered vent 7d is attached. Through the sintered vent 7d, the molten metal reservoir 7r is connected to a pressure reducing device (not shown). You. For this reason, when the pressure in the molten metal reservoir 7r of the gate piston 7 is reduced while the molten metal passage 8a is closed by the gate piston 7,
The molten metal is sucked into the molten metal reservoir 7r through the molten metal passage 8a and is stored in the molten metal reservoir 7r. Here, a thermal insulation layer 7e is formed by spraying ceramic on the inner wall surface of the gate piston 7, thereby suppressing the temperature rise of the gate piston 7 and keeping the temperature of the molten metal.
When the gate piston 7 rises in a state where the inside of the cavity 6 is reduced to a reference pressure by a vacuum pump (not shown), the molten metal in the molten metal passage 8a and the molten metal reservoir 7r passes through the sprue portion 6a and enters the cavity 6. Is sucked. At this time, even if the molten metal is rapidly sucked into the cavity 6, since the molten metal surface in the molten metal reservoir 7r is at a position higher than the gate 6a, no gas or the like is sucked into the cab 6. For this reason, casting defects are prevented.

[0004]

However, according to the above-mentioned conventional suction casting apparatus, when the gate piston 7 descends and the molten metal passage 8a is closed, the front end surface 7s of the gate piston 7 and the heat insulating layer 7e are closed. The lower end abuts on the upper surface 4j of the lower die 4. For this reason, the impact when the heat insulating layer 7e comes into contact with the upper surface 4j of the lower mold 4 is directly applied, and there is a problem that the heat insulating layer 7e is easily damaged. The technical problem of the present invention is to prevent the heat insulating member from coming into contact with the upper surface of the mold when the gate member closes the molten metal passage so that the impact at the time of closing is not directly applied to the heat insulating member. It is intended to make the member hard to break.

[0005]

The above-mentioned objects are attained by a casting apparatus having the following components. That is,
The casting apparatus according to claim 1 is a cylindrical game machine having a ceiling.
Cover member over the opening of the molten metal passage formed in the mold.
Block the molten metal passage and
In a casting apparatus having a structure for storing hot water, the gate member
The gate piston that constitutes the outer wall and the inner wall
A heat insulating member to be configured, wherein said gate piston
Has its tip surface in contact with the mold surface around the opening.
The heat insulating member.
Does not have its tip end surface in contact with the mold surface around the opening.
Must be attached to the gate piston
It is characterized by. According to the first aspect of the present invention, since the heat insulating member is attached to the gate piston such that the tip end surface does not contact the mold surface, the impact when the gate member closes the molten metal passage is directly applied to the heat insulating member. Will not join. For this reason, even if the said heat insulation member is a brittle member like ceramics, it will become difficult to be damaged, and the durability of a gate member will improve.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a detailed view of a gate member used in the casting apparatus according to the embodiment, and FIG. 2 is an overall sectional view of the casting apparatus according to the embodiment. The casting apparatus includes a mold 50 composed of an upper mold 52 and a lower mold 54, and a cavity 56 is formed in the center of the mold 50 in a state where the upper mold 52 and the lower mold 54 are clamped. It is formed. Further, a weir 5
A gate section 56a is formed via the base 6b, and the cavity 56 communicates with the molten metal passage 58 at this gate section 56a.

The molten metal passage 58 is formed by a passage 58a provided in the center longitudinal direction of the lower mold 54 and a cylindrical stalk 58b connected to the lower surface of the lower mold 54 while communicating with the passage 58a. Be composed. The leading end of the stalk 58b is immersed in a molten aluminum alloy 62 (hereinafter, referred to as molten metal 62) stored in a melting furnace 60 having an open top. An O-ring 64 made of heat-resistant rubber is provided on the mating surface between the lower mold 54 and the stalk 58b, thereby ensuring the airtightness of the molten metal passage 58.

A gate mechanism 70 for opening and closing the gate section 56a is provided at a connection portion between the gate section 56a of the cavity 56 and the molten metal passage 58. The gate mechanism 70 includes a gate piston 72, a moving mechanism (not shown) for displacing the gate piston 72 in the axial direction, and a pin 74 for connecting the gate piston 72 to the moving mechanism. I have.

As shown in FIG. 1, a detailed sectional view of the gate piston 72 is formed in a cylindrical shape, and its upper end is covered by an upper plate 72u. One end of a pin 74 for connecting the gate piston 72 and the moving mechanism is connected to the center of the upper plate 72u. Further, a through hole 72k is formed at the center of the upper plate 72u, and a sintering vent 76 capable of passing only gas without passing the molten metal 62 is attached to the through hole 72k. . An exhaust passage 74c is formed inside the pin 74 in the axial direction, and one end of the exhaust passage 74c communicates with the internal space of the gate piston 72 through the sinterable vent 76 having air permeability. . The other end of the exhaust passage 74c is connected to a pressure reducing device (not shown). With this structure, when the pressure reducing device operates, the internal space of the gate piston 72 is reduced in pressure through the exhaust passage 74c and the sintered vent 76.

A ceramic (silicon nitride Si ₃ N ₄ thermal conductivity: 0.05 to 0.09 cal / cm.se) is provided inside the gate piston 72.
c.) A cup-shaped heat insulating member 80 manufactured at ℃) is mounted. The heat insulating member 80 is manufactured so that its outer diameter is substantially equal to the inner diameter of the gate piston 72, and the center of the portion corresponding to the bottom of the cup projects outside. A flange 80t is provided at the tip of the protrusion, and a through hole 80k is formed at the center of the protrusion. The protruding portion of the heat insulating member 80 and the flange 80t are fitted with a metal coupling 82. The coupling 82 is connected to the upper plate 7 of the gate piston 72.
The heat insulating member 80 is fixed to the gate piston 72 by being fixed to 2u with the bolt 78. A through hole 82k is formed in the center of the coupling 82, and the through hole 82k of the heat insulating member 80 is formed by the through hole 82k.
0k communicates with a through hole 72k formed in the upper plate 72u of the gate piston 72.

An opening 52a is formed vertically in the center of the upper die 52, and the gate piston 72 is slidably housed in the opening 52a. Then, the gate piston 72 descends to the lower limit position and its tip surface 72s.
The gate piston 72 is put on the passage 58a formed in the lower mold 54 in a state where the end (except the tip of the heat insulating member 80) is in contact with the surface of the lower mold 54, and the passage 58a is closed and the cavity 56 is closed. The gate section 56a is closed. Here, the outer diameter of the heat insulating member 80 is manufactured to be smaller than the inner diameter of the passage 58 a formed in the lower mold 54. For this reason, the end surface 72s of the gate piston 72 is
4 does not come into contact with the surface of the lower mold 54. That is, the gate piston 72 and the cup-shaped heat insulating member 80 constitute the gate member of the present invention.

The gate piston 72 has a cavity 56.
When the pressure reducing device is driven in a state where the spout 56a is closed, the inside of the molten metal passage 58 becomes negative pressure, and the molten metal 62 stored in the melting furnace 60 is sucked from the stalk 58b and It is guided to the inside 80r (hereinafter referred to as a molten metal reservoir 80r). The degree of pressure reduction in the stalk 58b is set to about 400 mmHg (5.332 × 10 ⁴ Pa). Also, when the gate piston 72 slides upward and the tip end surface of the gate piston 72 moves away from the surface of the lower mold 54, the passage 58a of the lower mold 54 and the spout 56a of the cavity 56 are opened, and the molten metal is opened. Reservoir 80r communicates with both molten metal passage 58 and cavity 56. The outer surface of the gate piston 72 and the upper mold 52
An O-ring 73 made of heat-resistant rubber is provided between the inner surface of the opening 52a and the gate piston 7 (see FIG. 2).
Even if 2 slides up and down, the sealing property does not deteriorate.

As shown in FIG. 2, a cavity 56 formed inside the mold 50 is formed inside the upper mold 52 through a gap 53 formed in a mating surface between the upper mold 52 and the lower mold 54. In communication with the reduced pressure passage 52c. The pressure reducing passage 52c is connected to a vacuum pump (not shown). In order to ensure airtightness between the cavity 56 and the outside of the mold 50, an O-ring 53a made of heat-resistant rubber is provided at the edge of the mating surface of the upper mold 52 and the lower mold 54. With this structure, when the vacuum pump is driven in a state where the gate piston 72 closes the gate section 56a, the inside of the cavity 56 has a predetermined pressure reduction degree [20].
Torr (2.666 × 10 ³ Pa) or less].

Further, a pressurizing piston 52d for pressurizing the molten metal 62 filled in the cavity 56 is provided above the cavity 56. The pressurizing piston 52d is provided with a cylinder 52 formed inside the upper mold 52.
e can be slid in the vertical direction, and is operated by a piston drive mechanism (not shown). The pressing force of the pressurizing piston 52d is 200 to 1000.
It is set to a value of about Kg / cm ² (1.96 × 10 ^{7 to} 9.8 × 10 ⁷ Pa).

Next, the function of the casting apparatus according to this embodiment will be described. First, the gate 56a of the cavity 56 is closed by the gate piston 72, and the inside of the cavity 56 is depressurized by a vacuum pump. Further, the molten metal reservoir 80r in the gate piston 72 is reduced by the pressure reducing device.
Then, the pressure of the molten metal passage 58 is reduced, and the molten metal 62 stored in the melting furnace 60 is sucked to the molten metal reservoir 80r through the stalk 58b as shown in FIG. When the inside of the cavity 56 is depressurized to a predetermined decompression degree in a state where the molten metal reservoir 80r is filled with the molten metal 62, the gate piston 72 then rises and the spout 56a of the cavity 56 is opened. As a result, the molten metal 6 stored inside the molten metal passage 58 and the molten metal reservoir 80r
2 is quickly sucked into the cavity 56.

Here, the molten metal 62 is
When the suction is gentle, the molten metal 62 supplied to the cavity 56 can be almost supplemented by the molten metal passage 58, so that the level of the molten metal in the molten metal reservoir 80r is hardly reduced. However, when the suction from the cavity 56 is fast, the melt 1
Since the amount is insufficient, the shortage is the molten metal reservoir 80r.
Is supplemented by the molten metal 62 stored in the tank. here,
Since the surface of the molten metal 62 stored in the molten metal reservoir 80r is located at a position higher than the spout 56a, even if the molten metal 62 is rapidly sucked, the gas or the like in the molten metal reservoir 80r is sucked into the cavity 56. There is no. For this reason, casting defects are prevented.

When the molten metal 62 is filled in the cavity 56 in this way, the gate piston 72 descends and the spout 56a of the cavity 56 is closed again, and the molten metal 62 in the cavity 56 is closed by the pressurizing piston 52d. It is pressurized at a predetermined pressure. In parallel with this, the exhaust passage 74c is opened to the atmosphere, the molten metal 62 stored in the molten metal passage 58 and the molten metal reservoir 80r is returned into the melting furnace 60, and the casting is completed. As described above, according to the present embodiment, the heat insulating member 8 mounted inside the gate piston 72
0 indicates that the gate piston 72 is connected to the gate 5 of the cavity 56.
With the 6a closed, it does not come into contact with the surface of the lower mold 54. Therefore, the impact when closing the gate piston 72 is not directly applied to the heat insulating member 80, and the heat insulating member 80 is hardly damaged.

The heat insulating member 80 is a gate piston 72.
And is mounted inside the gate piston 72. Therefore, the thickness of the heat insulating member 80 can be set to a necessary and sufficient value, and the heat insulation of the gate piston 72 is improved. As a result, the temperature rise of the gate piston 72 becomes small, and problems such as seizure and galling hardly occur. In addition, the heat retaining property of the molten metal 62 is improved, and the solidified pieces generated on the inner wall surface of the heat insulating member 80 every casting are extremely thin, and the removal is easy.

[0019]

According to the present invention, even if the heat insulating member is made of a brittle material, it is hardly damaged, and the durability of the gate member is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a gate member used in a casting apparatus according to a first embodiment of the present invention.

FIG. 2 is an overall sectional view of the casting apparatus according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a gate piston used in a conventional casting apparatus.

[Explanation of symbols]

 Reference Signs List 50 mold 52 upper mold 54 lower mold 56 cavity 58 molten metal passage 72 gate piston (gate member) 80 heat-resistant member (gate member)

Claims (1)

(57) [Claims] 1. A cylindrical gate member having a ceiling portion is molded.
Cover the opening of the molten metal passage formed in
Close and store molten metal inside the gate member
In the casting apparatus, the gate member has a gate piston forming an outer wall thereof.
And a heat insulating member forming the inner wall of the gate piston.
Structure that closes the molten metal passage by contacting the mold surface
The heat-insulating member has a tip end surface around the opening.
So that it does not touch the surface,
Casting apparatus characterized by the fact that: