JP2820134B2 - 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. 5, the suction casting device includes a molten metal passage 8a and a cavity 6 formed in a mold (lower mold 4).
And a gate piston 7 which also functions as a molten metal reservoir. The gate piston 7 is a cylindrical member having an upper plate 7u, which is lowered to the lower limit position and its front end surface (lower end surface) 7s is formed on the upper surface 4j of the lower die 4.
The surface of the melt passage 8a and the cavity 6
You can cut off between. A permeable sintered vent 7d is mounted at the center of the upper plate 7u of the gate piston 7, and the inside of the gate piston 7 is connected to a vacuum pump (not shown) through the sintered vent 7d. Communicating. Further, ceramic is sprayed on the inner wall surface of the gate piston 7 so that the heat insulating layer 7 is formed.
e is formed, thereby suppressing the temperature rise of the gate piston 7 and keeping the temperature of the molten metal.

[0003]

However, according to the suction casting apparatus described above, since the heat insulating layer 7e is formed by spraying ceramic on the inner wall surface of the gate piston 7, the heat insulating layer 7e There is a problem that the heat insulating layer 7e is easily separated from the gate piston 7 due to the difference in thermal expansion coefficient between the two. The invention described in claim 1 is
By improving the method of attaching the heat insulating member (heat insulating layer) to the gate piston, the heat insulating member is prevented from peeling off due to the difference in the coefficient of thermal expansion between the two, and the durability of the gate piston is improved. is there. So far

[0004]

The above-mentioned objects are attained by a casting apparatus having the following components. That is,
The casting apparatus according to claim 1 has a structure in which a cylindrical gate member having a ceiling portion is covered 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. In the casting apparatus, the gate member has a gate piston forming an outer wall thereof and a heat insulating member forming an inner wall thereof, and the heat insulating member is attached to the gate piston at a ceiling. . For this reason, even if the heat insulating member and the gate piston expand at different rates of thermal expansion due to the heat of the molten metal, the heat insulating member and the gate piston can be freely displaced relative to each other at a portion other than the ceiling portion. Almost no force due to the difference in the coefficient of thermal expansion between the two is applied to the mounting portion (the ceiling) of the member. Therefore, the heat insulating member is less likely to come off the gate piston, and the durability of the gate member is improved.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] A casting apparatus according to a first embodiment of the present invention will be described below with reference to FIGS. Here, FIG. 1 is a detailed view of a gate member used in the casting apparatus according to the present embodiment, and FIG. 2 is an overall vertical sectional view of the casting apparatus according to the present embodiment. As shown in FIG. 2, the casting apparatus includes a mold 50 including an upper mold 52 and a lower mold 54, and the mold 50 is clamped in a state where the upper mold 52 and the lower mold 54 are clamped. A cavity 56 is formed in the center of the inside of 50. Further, a gate portion 56 is provided at a central portion of the cavity 56 through a weir portion 56b.
The cavity 56 communicates with the molten metal passage 58 at the 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, the gate piston 72 is formed in a tubular shape and has an upper plate 72u at an upper end thereof.
Has been capped by. 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, the upper plate 72u
A through-hole 72k is formed at the center of the hole, and a sintered vent 76 that allows only gas without passing through the melt 62 is attached to the through-hole 72k.

An exhaust passage 74c is formed in the pin 74 in the axial direction in the axial direction. One end of the exhaust passage 74c communicates with the internal space of the gate piston 72 through the permeable sintered vent 76. doing. 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 corresponding to the bottom (ceiling) of the cup protrudes upward. 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
Is fitted with a metal coupling 82. The coupling 82 is connected to the gate piston 72.
The heat insulating member 80 is fixed to the gate piston 72 by being fixed to the upper plate 72u with the bolt 78. A through hole 82k is formed in the center of the coupling 82 so that the through hole 82k allows the through hole 80k of the heat insulating member 80 to communicate with the through hole 72k formed in the upper plate 72u of the gate piston 72. become.

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 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. The reservoir 80r communicates with both the molten metal passage 58 and the cavity 56. An O-ring 73 made of heat-resistant rubber is provided between the outer surface of the gate piston 72 and the inner surface of the opening 52a of the upper die 52 (see FIG. 2), and the gate piston 72 slides up and down. Even if it moves, the sealing property does not deteriorate.

As shown in FIG. 2, a cavity 56 formed inside the mold 50 includes an upper mold 52 and a lower mold 54.
And a pressure reducing passage 52c formed inside the upper die 52 via a gap 53 formed on the mating surface with the upper mold 52. And
The decompression 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, the gate piston 7
When the vacuum pump is driven in a state in which the gate 2 is closed, the inside of the cavity 56 has a predetermined degree of pressure reduction [20
rr (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 the present 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 8 in the gate piston 72 is reduced by the pressure reducing device.
Or and the molten metal passage 58 are depressurized, and as shown in FIG. 2, the molten metal 62 stored in the melting furnace 60 is sucked to the molten metal reservoir 80r through the stalk 58b. When the inside of the cavity 56 is depressurized to a predetermined decompression degree in a state where the melt reservoir 80r is filled with the melt 62, the gate piston 72 then rises and the cavity 5
The gate section 56a of No. 6 is opened. As a result, the molten metal 62 stored in the molten metal passage 58 and the molten metal reservoir 80r 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 amount of the molten metal supplied through the molten metal passage 58 is insufficient.
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 80 is manufactured separately from the 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 heat insulating member 8 is provided every casting.
The solidified pieces generated on the inner wall surface of the zero are also very thin, and the removal is easy.

Further, only the ceiling of the heat insulating member 80 is coupled to the upper plate 72 u of the gate piston 72 by the coupling 8.
2 is fixed. For this reason, even if the heat insulating member 80 and the gate piston 72 expand at different rates of thermal expansion due to the heat of the molten metal 62, the heat insulating member 80 and the gate piston 72 can be freely displaced relative to each other at a portion other than the ceiling. On the other hand, the force (due to the difference in the coefficient of thermal expansion) between the heat insulating member 80 and the gate piston 72 is hardly applied to the mounting portion (the ceiling) of the gate piston 72. Therefore, the heat insulating member 80 does not easily come off the gate piston 72, and the durability of the gate member is improved.

[Second Embodiment] Next, a casting apparatus according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a detailed sectional view of the gate piston 172 used in the casting apparatus according to the present embodiment, and FIG. 4 is an overall vertical sectional view of the casting apparatus according to the present embodiment. The casting apparatus includes a mold 150 composed of an upper mold 152 and a lower mold 154. A cavity 156 is formed at the center of the inside of the mold 150 in a state where the upper mold 152 and the lower mold 154 are clamped. It is formed. Further, the cavity 1
At the center of 56, the spout 156 is connected via a weir 156b.
a is formed, and the cavity 156 communicates with the molten metal passage 158 at the gate section 156a.

The molten metal passage 158 includes a passage 158a provided in the center longitudinal direction of the lower mold 154 and a passage 158a.
And a cylindrical stalk 158b connected to the lower surface of the lower die 154 while communicating with the lower die 154. The tip of the stalk 158 b is immersed in the molten metal 162 stored in the melting furnace 160. Here, the melting furnace 160 has a closed structure, and an opening 160a is formed in an upper side surface thereof. And this opening 16
Oa is connected to a pressurizing device (not shown) for pressurizing the inside of the melting furnace 160. The lower mold 15
4 and Stoke 158b are joined by heat resistant rubber O
A ring 164 is provided to ensure airtightness of the molten metal passage 158.

At the connection between the gate 156a of the cavity 156 and the molten metal passage 158, the gate 15
A gate mechanism 170 for opening and closing 6a is installed. The gate mechanism 170 includes a gate piston 172,
A moving mechanism (not shown) for displacing the gate piston 172 in the axial direction, and a pin 174 for connecting the gate piston 172 to the moving mechanism
It has.

As shown in FIG. 3, the gate piston 172 is formed in a cylindrical shape and its upper end is covered by an upper plate 172u. One end of a pin 174 for connecting the gate piston 172 and the moving mechanism is connected to the center of the upper plate 172u. Further, a through hole 172 is provided at the center of the upper plate 172u.
k is formed, and a sintered vent 176 that allows only gas to pass therethrough is attached to the through hole 172k. An exhaust passage 174c is formed inside the pin 174 in the axial direction.
One end of 4c communicates with the internal space of the gate piston 72 via the sintered vent 176. The other end of the exhaust passage 174c is open to the atmosphere.

Inside the gate piston 172, T
A cup-shaped heat insulating member 180 made of i-alloy (Ti-6A1-4V, thermal conductivity 0.018 cal / cm.sec. ° C.) is mounted. Since the heat insulating member 180 is made of metal, it can be easily processed as compared with the silicon nitride used in the first embodiment. For this reason, a portion corresponding to the bottom (ceiling) of the cup of the heat insulating member 180 is directly connected to the gate piston 17.
2 is fixed to the upper plate 172u with bolts 178. Further, a through hole 180k is provided at the center of the ceiling of the heat insulating member 180.
The through hole 180k is connected to a through hole 172k formed in the upper plate 172u of the gate piston 172. A heat-resistant O-ring 184 for sealing is provided at a joint between the upper surface of the heat insulating member 180 and the upper plate 172u of the gate piston 172.

The distal end portion of the heat insulating member 180 projects beyond the distal end surface 172s of the gate piston 172. When the gate piston 172 is located at the lower limit, the distal end surface 180s of the heat insulating member 180 is lowered to the lower die 154. To come into contact with the surface. With this structure, the impact at the time of closing the gate piston 172 is generated by the heat insulating member 180.
However, since the heat insulating member 180 is made of metal and is not brittle, there is no breakage. That is,
The gate piston 172 and the heat insulating member 180 constitute the gate member of the present invention.

Further, the gate piston 172 slides upward, and the tip end surface of the gate piston 172 is moved to the lower mold 154.
Away from the surface, the passage 158a of the lower mold 154 and the sprue 156a of the cavity 156 are opened, and the molten metal reservoir 180r communicates with both the molten metal passage 158 and the cavity 156. An O-ring 173 (see FIG. 4) made of heat-resistant rubber is provided between the outer surface of the gate piston 172 and the inner wall surface of the opening 152a of the upper die 152, and the gate piston 172 slides up and down. Even so, the sealing property is not deteriorated.

As shown in FIG. 4, the cavity 156 formed inside the mold 150 includes an upper mold 152 and a lower mold 1.
Through the gap 153 formed on the mating surface with the upper mold 15.
2 and communicates with a decompression passage 152c formed inside. The pressure reducing passage 152c is connected to a vacuum pump (not shown). The cavity 156
An O-ring 153a made of heat-resistant rubber is provided at the edge of the mating surface between the upper mold 152 and the lower mold 154 in order to ensure airtightness between the mold 150 and the outside. With this structure, when the vacuum pump is driven with the gate piston 172 closing the gate 156a, the cavity 1
The inside of 56 has a predetermined pressure reduction degree [20 Torr (2.666 × 10 ³ Pa)
Below).

Further, a pressurizing piston 152d for pressurizing the molten metal 62 filled in the cavity 156 is provided above the cavity 156. The pressurizing piston 152d can slide up and down in a cylinder 152e formed inside the upper die 152, and is operated by a piston drive mechanism (not shown). The pressure applied by the pressurizing piston 152d is set to a value of about 200 to 1000 kg / cm ² (1.96 × 10 ^{7 to} 9.8 × 10 ⁷ Pa).

Next, the function of the casting apparatus according to the present embodiment will be described. First, the gate 156a of the cavity 156 is closed by the gate piston 172, and the inside of the cavity 156 is depressurized by a vacuum pump. Further, the inside of the melting furnace 160 is pressurized by a pressurizing device, and the molten metal 162 stored in the melting furnace 160 is melted.
Is pressed, and the molten metal 162 is pushed up to the molten metal reservoir 180r of the gate piston 172 via the stalk 158b. When the inside of the cavity 156 is depressurized to a predetermined decompression degree in a state where the molten metal reservoir 180r is filled with the molten metal 162, the gate piston 172 then rises and the spout 156a of the cavity 156 is opened. Thereby, the molten metal passage 158 and the molten metal reservoir 1
Molten metal 162 stored inside 80r is quickly sucked into cavity 156.

When the cavity 156 is filled with the molten metal 162 in this manner, the gate piston 172 descends, the gate 156a of the cavity 156 is closed again, and the cavity 156 is pressed by the pressurizing piston 152d.
The molten metal 162 is pressurized at a predetermined pressure. Also, in parallel with this, the inside of the melting furnace 160 is opened to the atmosphere,
The molten metal 162 stored in the molten metal passage 158 and the molten metal reservoir 180r is returned into the melting furnace 160, and the casting is completed.

As described above, according to the present embodiment, the heat insulating member 1
Reference numeral 80 is manufactured separately from the gate piston 172, and is mounted inside the gate piston 172. Therefore, the thickness of the heat insulating member 180 can be set to a necessary and sufficient value, and the heat insulation of the gate piston 172 is improved. As a result, the rise in temperature of the gate piston 172 is reduced, and problems such as seizure and galling hardly occur. In addition, the heat retention of the molten metal 162 is improved, and solidified pieces generated on the inner wall surface of the heat insulating member 180 every casting are extremely thin.
Removal is easier.

Further, only the ceiling of the heat insulating member 180 is fixed to the upper plate 172u of the gate piston 172. For this reason, even if the heat insulating member 180 and the gate piston 172 expand at different thermal expansion rates due to the heat of the molten metal, the heat insulating member 180 and the gate piston 172 can be freely displaced relative to each other at a portion other than the ceiling portion. A force due to a difference in the coefficient of thermal expansion between the two members 172 and 180 is hardly applied to a mounting portion (ceiling portion) of the heat insulating member 180 with respect to the gate piston 172. Therefore,
The heat insulating member 180 does not easily come off the gate piston 172, and the durability of the gate member is improved. Further, since the heat insulating member 180 is made of metal, it can be processed easily and its shape can be freely set as compared with ceramics. Further, the cost can be reduced because the processing is simple.

In the casting apparatus according to the present embodiment,
Gate piston 1 having heat insulating member 180 made of Ti alloy
Although the example using 72 is shown, the gate piston 7 having the ceramic heat insulating member 80 shown in the first embodiment is used.
It is also possible to use 2. Conversely, the gate piston 72 having the ceramic heat insulating member 80 used in the casting apparatus according to the first embodiment is replaced with the gate piston 172 having the Ti alloy heat insulating member 180 shown in the present embodiment. It can be changed.

Although the embodiments of the present invention have been described above, it is to be understood that the embodiments of the present invention have the following technical matters in addition to the technical matters described in the claims. Please note. (1) The casting apparatus according to claim 1, wherein the heat insulating member is manufactured separately from the gate piston. Therefore, the thickness of the heat insulating member can be set to a desired value. (2) In the casting apparatus according to claim 1, the gate member is provided with a gas-permeable vent at a ceiling portion for fixing a gate piston and a heat insulating member, and the internal space of the gate member is formed by the vent. And a sealing ring mounted around the gate piston and the heat insulating member between the gate piston and the heat insulating member. apparatus. Even if a gap is formed between the gate piston and the heat insulating member, the airtightness of the internal space of the gate member is maintained.

[0035]

According to the present invention, since the force caused by the difference in the coefficient of thermal expansion between the two parts is hardly applied to the place where the heat insulating member is attached to the gate piston, the heat insulating member hardly comes off from the gate piston, and The durability of the 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 vertical sectional view of the casting apparatus according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a gate member used in a casting apparatus according to a second embodiment of the present invention.

FIG. 4 is an overall vertical sectional view of a casting apparatus according to a second embodiment of the present invention.

FIG. 5 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) 172 gate piston (gate member) 180 heat-resistant member (gate member)

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuyuki Arakawa 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-5-212528 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) B22D 18/06 509 B22D 18/02 B22D 18/04

Claims (1)

(57) [Claims] 1. A casting apparatus having a structure in which a cylindrical gate member having a ceiling portion is covered with 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. A gate member, a gate piston constituting the outer wall thereof,
And a heat insulating member constituting an inner wall, wherein the heat insulating member is attached to the gate piston at a ceiling.