JP2000271716A - Vacuum forming apparatus for die casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of casting blow hole by preventing the entrapment of the air at molten metal injection. SOLUTION: In a nozzle body 11, a pressure chamber 26 is arranged. When the pressure in the pressure chamber 26 is raised, a valve tip 45 is energized to close the flowing passage of a nozzle base 42. Then, when the nozzle body 11 and a product forming part 10' become in the vacuum state, the valve tip 45 energized in the opening direction of a flowing passage with a valve spring 37, is opened and the molten metal is filled and solidified into the product forming part 10' without entraping the air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum molding apparatus for die casting for vacuum injection molding of a molten metal such as a zinc alloy or a magnesium alloy.

[0002]

2. Description of the Related Art FIG. 23 is a sectional view showing a general structure of a die casting apparatus. In FIG. 23, the machine nozzle 4 and the mold 7 of the die casting machine are about 10
In addition, the molten metal injection part 4a of the mechanical nozzle 4 has a molten surface 9a of the molten metal (molten metal 9) in the melting furnace 1.
Of the molten metal injection part 4a
It has a structure to prevent hot water from flowing out.

When a product is formed by this die casting apparatus, first, a molten metal 9 melted in a melting furnace 1 is sent out by a plunger 3 reciprocating within a sleeve 2 and passes through a mechanical nozzle 4. Then, it is injected into the mold 7. The mold 7 includes a fixed mold 7a and a movable mold 7b. The molten metal injected from the mechanical nozzle 4 passes through a sprue bush 6 of the fixed mold 7a, and is formed into a product forming part formed by the fixed mold 7a and the movable mold 7b. 8 '.

At this time, the inside of the machine nozzle 4, the inside of the sprue bush 6, and the inside of the product forming portion 8 'are filled with air. For this reason, the filled molten metal advances while pushing out the air filled in the product forming portion 8 ′ from the gap of the mold 7. However, since the speed of the molten metal is very high, the molten metal may entrain the air. There is. The air entrained in the molten metal as described above is partially left in the molten metal filled in the product forming section 8 '.

Thereafter, the molten metal supplied to the product forming section 8 'as described above is cooled by the mold 7 and solidified. Then, the movable mold 7b is moved in the direction of arrow A to open the mold 7, and the product section 8a, the runner section 8b,
The molded product 8 integrated with the sprue portion 8c is taken out. The molded article 8 is formed by breaking off the runner section 8b together with the sprue section 8c at the gate section 8d. Here, in the case where the protrusion of the portion where the runner portion 8b is cut off is not allowed, or when high shape accuracy is required, the portion where the runner portion 8b is cut off is subjected to file processing, cutting processing, and the like. Is arranged.

As shown in FIG. 23, the sprue bush 6 in the die casting apparatus is cooled by cooling water 31 circulating in the outer peripheral portion, and the sprue portion 8c due to insufficient cooling when the mold 7 is opened. It was configured to prevent premature disconnection.

Further, the outer periphery of the mechanical nozzle 4 is heated by the mechanical nozzle heater 5 so that the molten metal does not solidify in the mechanical nozzle. Furthermore, the injection part 4a of this machine nozzle
Was set in a state of being pressed against the mechanical nozzle touch portion 6a (see FIG. 25) of the sprue bush 6 so that the molten metal did not leak.

[0008]

As described above, since the molten metal is injected into the mold 7 at a high speed, air is inevitably entrained in the molten metal, and when a molded product is solidified, a cavity is formed therein. Let me do it. With such a cavity, when the runner portion 8b is cut off or cut as described above, the cavity is exposed on the surface and becomes a hole, and a correct shape cannot be obtained. In addition, when performing the surface treatment, there is a problem that the surface treatment cannot be performed to the depth of the hole. Also, when plating is performed, there is a problem that the plating solution remains in the holes and the corrosion resistance is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has a vacuum inside a mold to eliminate the entrapment of air during injection of molten metal and eliminate the occurrence of cavities. An apparatus is provided.

[0010]

Means for Solving the Problems Claim 1 of the present invention
In the vacuum forming apparatus for die-casting according to the present invention, a nozzle tip as a molten metal injection section is fixed to a tip end portion of a nozzle body, and the nozzle tip insulates the mold and maintains a position in the mold. Is fixed to the nozzle body. In addition, the heat-insulating ring and the mold, and the heat-insulating ring and the nozzle tip are always fitted with a gap at room temperature and when the temperature rises during molding, so that the heat-insulating ring is prevented from being damaged. . Further, a compressible heat-resistant gasket is provided between the nozzle body and the heat insulating ring to prevent the passage of the molten metal. In addition, a gasket is provided between the heat insulating ring and the mold in order to keep the product molded portion of the mold in a vacuum. On the other hand, a valve tip that is guided by a valve guide and that can move along the flow path is provided in the nozzle body. The valve chip is pressed against the nozzle base of the nozzle body by the pressure in the pressure chamber formed by the valve guide, and acts to close the flow path and maintain airtightness in the nozzle body. The pressure in the pressure chamber is increased by compressed air sent from a pressure source via a connecting pipe, and urges the valve chip. Further, since the valve chip is urged by the elastic member in a direction to open the flow path of the molten metal, when the pressure in the pressure chamber is reduced, the flow path is opened, and the molten metal is poured from the flow path into the product forming portion of the mold. It has become something. Further, the vacuum source is for bringing the product forming portion of the mold into a vacuum state, and the inside of the nozzle body is also brought into a vacuum state together with the product forming portion to prevent air from being entrained at the time of injection of the molten metal.

In the vacuum forming apparatus for die casting according to a second aspect of the present invention, the heat insulating ring is directly fixed to the tip of the nozzle body. The fitting between the heat insulating ring and the mold is always a clearance fit at both room temperature and when the temperature rises during molding, so that the heat insulating ring is prevented from being damaged. Further, a compressible heat-resistant gasket is provided between the nozzle body and the heat insulating ring to prevent the passage of the molten metal. In addition, a gasket is provided between the heat insulating ring and the mold in order to keep the product molded portion of the mold in a vacuum. On the other hand, a valve tip that is guided by a valve guide and that can move along the flow path is provided in the nozzle body. The valve chip is pressed against the nozzle base of the nozzle body by the pressure in the pressure chamber formed by the valve guide, and acts to close the flow path and maintain airtightness in the nozzle body. The pressure in the pressure chamber is increased by compressed air sent from a pressure source via a connecting pipe, and urges the valve chip. Further, since the valve chip is urged by the elastic member in a direction to open the flow path of the molten metal, when the pressure in the pressure chamber is reduced, the flow path is opened, and the molten metal is poured from the flow path into the product forming portion of the mold. It has become something. Further, the vacuum source is for bringing the product forming portion of the mold into a vacuum state, and the inside of the nozzle body is also brought into a vacuum state together with the product forming portion to prevent air from being entrained at the time of injection of the molten metal.

According to a third aspect of the present invention, there is provided a vacuum forming apparatus for die-casting, wherein a heat-resistant gasket is provided by being compressed between a heat insulating ring and a nozzle tip.

The vacuum forming apparatus for die-casting according to claim 4 of the present invention uses a heat-resistant metal material having a higher thermal conductivity than heat-resistant steel for the nozzle body and the nozzle tip.

Further, in the vacuum forming apparatus for die casting according to claim 5 of the present invention, a heat-resistant metal material having higher thermal conductivity than heat-resistant steel is used for the nozzle body.

Further, in the vacuum forming apparatus for die casting according to claim 6 of the present invention, the valve tip has a first contact portion having a conical surface shape, and the nozzle body is provided at a portion where the first contact portion of the valve tip contacts. It is configured to have a conical contact portion.

According to a seventh aspect of the present invention, there is provided the vacuum forming apparatus for die casting, wherein the valve tip has a spherical shape.
The nozzle body has a contact portion, and the nozzle body is configured to have a conical contact portion at a portion where the first contact portion of the valve tip contacts.

Further, in the vacuum forming apparatus for die-casting according to claim 8 of the present invention, the valve tip has a spherical first shape.
The nozzle body has a contact portion, and the nozzle body has a spherical contact portion having a radius equal to or slightly larger than the first contact portion at a portion where the first contact portion of the valve chip contacts.

According to a ninth aspect of the present invention, there is provided a vacuum forming apparatus for die casting, wherein a valve guide for guiding a valve chip and forming a pressure chamber is provided in a nozzle body, and the valve chip has a conical second contact portion. And the valve guide is configured to have a conical contact portion at a portion where the second contact portion of the valve tip contacts.

According to a tenth aspect of the present invention, there is provided a vacuum forming apparatus for die casting, wherein a valve guide for guiding a valve chip and forming a pressure chamber is provided in a nozzle body, and the valve chip has a spherical second contact portion. The valve guide has a conical contact portion at a portion where the second contact portion of the valve tip contacts.

Further, in the vacuum forming apparatus for die casting according to claim 11 of the present invention, a valve guide for guiding a valve chip and forming a pressure chamber is provided in a nozzle body, and the valve chip has a spherical second contact portion. The valve guide has a spherical contact portion having a radius equal to or slightly larger than that of the second contact portion at a portion where the second contact portion of the valve tip contacts.

According to a twelfth aspect of the present invention, there is provided a vacuum forming apparatus for die casting, wherein a valve guide for guiding a valve chip and forming a pressure chamber is provided in a nozzle body, and the valve chip and the valve guide slide. A metal C-ring is provided in the portion.

Further, in the vacuum forming apparatus for die casting according to claim 13 of the present invention, a heating means capable of controlling the temperature is provided in the nozzle body.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The nozzle body of the vacuum forming apparatus for die casting according to the present invention is a hot nozzle because it is supplied with heat from the mechanical nozzle by contact with the mechanical nozzle and is insulated from the mold. The molten metal in the nozzle body is kept in a molten state. In the nozzle body, a valve tip movable along the flow path and a pressure chamber formed by a valve guide for guiding the valve tip are provided. The pressure chamber is connected to a pressure source via a connecting pipe, and the pressure in the pressure chamber is increased by compressed air from the pressure source to urge the valve chip to close the flow path. That is, the nozzle body is composed of a nozzle body, a valve guide and a nozzle base, and the valve chip is guided by the valve guide and pressed against the nozzle base by the pressure in the pressure chamber. The nozzle base forms an inlet of a flow path into which the injected molten metal flows, and the valve tip is pressed against the nozzle base so as to close the flow path of the nozzle base. When the flow path of the molten metal is closed in this way, the molten metal does not flow into the nozzle body from the contact portion between the valve chip and the valve base even when the product forming portion of the mold is decompressed to a state close to a vacuum. Absent. When the pressure chamber is not connected to the pressure source and is open to the atmosphere, the valve tip moves in a direction to open the flow path by a valve spring as an elastic member.

As described above, in the vacuum forming apparatus for die casting of the present invention, it is possible to maintain the product forming portion of the mold in a reduced pressure state close to a vacuum. Therefore, when the product forming part of the mold is depressurized by the vacuum source and the valve tip is moved to open the flow path of the melt in this state, the melt flows from the nozzle body into the product forming part of the mold. At this time, since the product forming section is in a vacuum state, the molten metal is filled into the product forming section and solidified without involving air. Therefore,
The occurrence of cavities due to the entrainment of air is almost eliminated, and the accuracy and quality of the product can be improved.

As described above, since the nozzle body is a hot nozzle, the molten metal in the nozzle body can be maintained in a molten state. The filling of the molten metal into the finely shaped portion and the ultrathin portion is facilitated, and insufficient filling is eliminated.

In particular, when molten metal flows between the nozzle body and the mold, heat escapes from the nozzle body to the mold via the molten metal,
Since the temperature of the nozzle main body cannot be maintained at a temperature suitable for die casting, it is necessary to reliably prevent the flow of the molten metal between the nozzle main body and the mold. In the present invention, a heat-resistant gasket and a gasket are provided between the respective parts, not only to improve airtightness, but also to prevent molten metal from flowing between the mold and the nozzle body, thereby ensuring heat insulation.

Further, by providing a heat-resistant gasket between the heat insulating ring and the nozzle tip, a slight leak of the molten metal from the inside of the nozzle body passing through the mounting screw portion of the nozzle tip can be surely prevented. Who can be prevented.

When a material having good thermal conductivity is used for the nozzle body or the nozzle body and the nozzle tip, heat transfer to the nozzle tip (injection portion) is performed in a short time, and the molding start time after the die is mounted. Can be shortened, and the molding cycle can be shortened easily.

Further, since the contact portion between the valve tip and the nozzle base for opening and closing the flow path is formed of a conical surface and a conical surface, a spherical surface and a conical surface, or a spherical surface and a spherical surface, the valve chip is inclined. Also, the valve tip and the nozzle base can be surely brought into close contact with each other.

Further, since the contact portion between the valve tip and the valve guide is formed of a conical surface and a conical surface, a spherical surface and a conical surface, or a spherical surface and a spherical surface, respectively, even if the valve tip is inclined, the valve tip and the valve guide may be inclined. The valve guide can be surely brought into close contact, and the molten metal can be reliably prevented from flowing into the pressure chamber from the sliding portion between the valve tip and the valve guide.

Further, since the metal C-ring is provided on the sliding portion where the valve tip and the valve guide slide, even if the gap between the sliding portions becomes large due to wear, the molten metal from the sliding portion can be removed. Inflow can be prevented.

On the other hand, by providing the nozzle body with a heating means capable of controlling the temperature, the nozzle body is heated not only by the heat supply from the mechanical nozzle but also by the heat of the heating means, so that the optimum temperature is quickly reached. . For this reason, it is possible to shorten the time from the mounting of the mold to the start of molding. Such heating by the heating means is particularly effective when a long nozzle body is used or when a metal material having a high melting point is formed.

[0033]

FIG. 1 is a sectional view showing a state in which a vacuum forming apparatus for die casting according to one embodiment of the present invention is incorporated in a mold 22 and is mounted on a die casting machine. FIG. 2 is a sectional view showing the vacuum for die casting shown in FIG. It is a principal part expanded sectional view which shows the detailed structure of a shaping | molding apparatus. FIG. 3 is a partial detailed view of the vacuum forming apparatus for die casting shown in FIG. 4 and 5 are sectional views showing the state of the vacuum forming apparatus for die casting at the time of molding. FIGS. 6 and 7 are side views of the vacuum forming apparatus for die casting as viewed from the molten metal outflow side and the molten metal inflow side. is there.

As shown in FIGS. 1 to 3, the fixed die 22a of the mold 22 is provided with a substantially cylindrical mounting hole 22d, and the nozzle body 11 is accommodated in the mounting hole 22d. The nozzle body 11 has a substantially cylindrical nozzle body 41, a nozzle base 42 provided at an end of the nozzle body 11 on the molten metal inflow side, and a valve guide provided between the nozzle body 41 and the nozzle base 42. 50. Both the nozzle body 41 and the nozzle base 42 have a flange 4
1 a and 42 d, and a set screw 44 is screwed and connected to penetrate the flange portions 41 a and 42 d and the valve guide 50. A nozzle tip 21 is attached to the end of the nozzle body 41 on the molten metal outflow side. The nozzle tip 21 has a flange-shaped tip portion 21a on the outer periphery of the tip, and a screw portion 21b is formed on the outer periphery of the other end portion. The screw portion 21b is provided inside the end portion of the nozzle body 41. It is fixed to the nozzle body 41 by being screwed into the formed screw portion 41b.
As shown in FIG. 12, the slit groove 32 provided on the end face of the nozzle tip 21 in the melt inflow direction is
This is for inserting a tool when screwing the nozzle tip 21 into the nozzle body 41. The nozzle body 11 and the nozzle tip 21 having the above configuration have a higher thermal conductivity than heat-resistant steel or heat-resistant steel, for example, a heat conductivity of 0.3 cal /.
It is made of a tungsten alloy having a temperature of sec · cm · ° C. or more. A mechanical nozzle touch portion 42c is provided on the outer end surface of the nozzle base 42 on the molten metal inflow side, and an annular concave portion 41c adapted to a heat-resistant gasket described later is provided on the outer end surface of the nozzle body 41 on the molten metal outflow side. Is provided.

As shown in FIGS. 8 to 11, the valve guide 50, which constitutes a part of the nozzle body 11, protrudes inward of the nozzle body 41 and has a cover 3 at the end opening.
8, a bottomed hole 50 b formed from the end face on the melt inflow side toward the melt outflow direction, and a connection hole 5 communicating from the outer peripheral surface to the hole 50 b.
0d and a plurality of flow paths 50e provided around the hole 50b.
And a through hole 50f through which the above-mentioned set screw 44 passes, and a through hole 50i that connects the protrusion 50a and the hole 50b. A sliding portion 45b of the valve chip 45 that is movable in the direction in which the molten metal flows is slidably fitted in the hole 50b of the valve guide 50. In this valve chip 45, the sliding portion 45b slides toward the nozzle base 42 by the pressure of the pressure chamber 26 formed in the hole 50b. The valve tip 45 is provided with the through hole 5
0i, the flow path is always opened (left direction in the figure) by the valve spring 37 provided between the spring receiver 30 attached to the end of the sliding portion 45b and the peripheral edge of the through hole 50i.
Has been energized. A contact portion 45a having a conical surface is provided at a portion of the end of the valve chip 45 facing the nozzle base 42. On the other hand, a conical contact portion 42a is provided at a portion of the nozzle base 42 facing the contact portion 45a of the valve tip 45. The contact portions 45a and 42a come into close contact with each other when the sliding portion 45b slides due to the pressure of the pressure chamber 26. The close contact can seal the flow path 42b of the nozzle base 42. On the other hand, the pressure chamber 26 is configured to be supplied with compressed air from a pressure source 28 (FIG. 1) via a connection pipe 27 so as to increase the internal pressure. The connection pipe 27 is fixed so as to communicate with the connection hole 50d of the valve guide 50, and a heat-resistant gasket 29 is provided between the valve guide 50 and the connection pipe 27 to prevent leakage of compressed air. ing.

The heat insulating ring 12 is made of a material having good heat resistance and low thermal conductivity, such as ceramic, and a material having mechanical strength enough to withstand screwing and pressing. A nozzle tip 21 is provided on an end surface of the heat insulating ring 12 on the emission side.
An annular concave portion 12a that fits the front end portion 21a is provided. As shown in FIG. 2, when the nozzle tip 21 penetrating the heat insulating ring 12 is fixed to the nozzle body 41 as shown in FIG.
a and the end surface of the nozzle body 41. The heat insulating ring 12 has an outer diameter that can be fitted into the heat insulating ring fitting portion 22ab at the end of the mounting hole 22d on the molten metal outflow side.

The heat-resistant gaskets 14, 43 and 25 are provided between the heat insulating ring 12 and the nozzle body 41,
1 and the valve guide 50, and between the valve guide 50 and the nozzle base 42, respectively, to prevent the molten metal from flowing out or the air from flowing in between them. The heat-resistant gaskets 14, 43, and 25 are made of a soft material such as gold or copper having a certain degree of heat resistance, a metal O-ring, a metal C-ring, or a metal U-ring made of stainless steel, inconel, hastelloy, or the like. With the recess 41c of the nozzle body 41 and the valve guide 50
Are small enough to fit in the recesses 50g, 50h (FIG. 8) of the
c, 50 g, and 50 h. This heat-resistant gasket 14, 43, 25
As described above, the heat insulating ring 12 is
1 and when the nozzle base 42 and the valve guide 50 are fixed to the nozzle body 41, respectively, are compressed between them. The heat-resistant gaskets 14, 43, and 25 compressed in this way are used for melting the molten metal into the nozzle body 4.
It works so as to prevent the gas from flowing out between the mold 22 and the nozzle body 11 through a gap between the heat insulating ring 1 and the heat insulating ring 12 or a gap between the nozzle body 41 or the nozzle base 42 and the valve guide 50. Further, it also acts to maintain the airtightness in the nozzle body 11. The above-mentioned heat-resistant gasket 29 is also used for these heat-resistant gaskets 1.
4, 43 and 25 are made of the same material and configuration.

The gasket 47 made of an O-ring or the like is made of a heat-resistant material such as fluorine rubber or silicon rubber or a metal C-ring as described later when the temperature of the molten metal is high. It is housed in an annular groove 22aa provided on the inner circumference of the heat insulating ring fitting portion 22ab. The gasket 47 has mechanical elasticity in the radial direction, and has a fixed mold 22a and a heat insulating ring 1.
2 to prevent air from flowing into the gap between the fixed mold 22a and the heat insulating ring 12 therebetween.

The guide rings 23 and 24 have heat resistance,
The guide ring 23 is fitted on the nozzle main body 11 so as to sandwich the flange portions 41a and 42d, and is positioned by being locked to the step in the mounting hole 22d. This is to support the nozzle body 11 in contact with it and position the mechanical nozzle touch portion 42c at an appropriate position.

The back plate 15 is fixed to the end surface of the fixed die 22a with screws 16 in order to prevent the nozzle body 11 and the guide rings 23 and 24 from dropping out of the mounting holes 22d.

The vacuum source 20 (FIG. 1) sucks air in the product forming section 10 ′ of the mold 22 to reduce the pressure to make a vacuum or a state close to a vacuum. The movable mold 22b is provided with an air escape groove 22ba and air escape holes 22bb, 22bc communicating with the product forming section 10 '. The air escape groove 22ba and the air escape holes 22bb, 22bc are configured to allow air to flow therethrough. When the air escape hole 22bc is connected to the vacuum source 20, the air escape groove 22ba, the air escape hole 22bb, The air in the product forming section 10 ′ is sucked by the vacuum source 20 through the 22 bc. Further, the movable die 22b is provided with a shut-off pin 48 for separating the product forming portion 10 'from the air escape groove 22ba. The shut-off pin 48 is slidable in the directions of arrows B and C in FIG. 1 (in the left-right direction in FIG. 2). The communication with the groove 22ba can be made or cut off.

In the die-casting vacuum forming apparatus having the above structure, when the die-casting is started, first, the mold 22 is closed, and the fixed mold 22a and the movable mold 22b are brought into close contact with each other, and the state shown in FIG. 4 is obtained. In this state, the shut-off pin 48 is drawn out of the air escape groove 22ba as shown in FIG. 4, so that when the air is sucked by the vacuum source 20, the inside of the nozzle body 11 and the mold 22 The product forming section 10 'is decompressed and almost in a vacuum state. Thereafter, when the shut-off pin 48 moves in the direction of arrow B, as shown in FIG. 2, the air escape groove 22ba is shut off, and the inside of the nozzle body 11 and the product forming part 10 'of the mold 22 are kept in a vacuum state. .

In the state shown in FIG.
The sealing when the pressure is reduced by the vacuum source 20 connected to the gasket 47 and the heat-resistant gaskets 14, 43, 2
5 and the valve tip 45 and the nozzle base 42 are kept in close contact. Although a small amount of air flows in between the hole 50b of the valve guide 50 and the sliding portion 45b of the valve chip 45, the degree of vacuum can be almost maintained by minimizing the gap at this portion. Can be.

At this time, the valve chip 45
When the pressure in the pressure chamber 26 is increased by the compressed air from the pressure source 28, the pressure chamber 26 slides rightward in FIG. 2 against the valve spring 37, and the contact portion 45a comes into close contact with the contact portion 42a of the nozzle base 42. In the state, the nozzle base 4
The second flow path 42b is closed. The pressure in the pressure chamber 26 is set to a magnitude that keeps the valve tip 45 in close contact with the nozzle base 42 without moving even when the inside of the nozzle body 11 is in a vacuum state. Also,
When the air escape groove 22ba is shut off by the shut-off pin 48, the connection between the connection pipe 27 and the pressure source 28 is also released, and the pressure chamber 26 is connected to the atmosphere and depressurized. For this reason, the pressing of the valve tip 45 in the direction of the nozzle base 42 is released, and as shown in FIG. 5, the valve tip 45 moves to the left in the figure by the valve spring 37 to open the flow path. After the connection between the connection pipe 27 and the pressure source 28 is released, the connection pipe 27 may be connected to the vacuum source 20 to make the pressure chamber 26 vacuum.

In this state, when the molten metal is pressurized by the plunger 3 of the die casting machine, the molten metal is injected from the mechanical nozzle 4 to the nozzle body 11. At this time, since the valve tip 45 has already moved in the direction to open the flow path, the molten metal flows into the nozzle main body 11 and passes through the flow path 50e of the valve guide 50 from the nozzle tip 21 to the inside of the product forming section 10 '. Flow into At this time, the nozzle body 11
Since the inside and the product forming part 10 ′ of the mold 22 are almost in a vacuum state, the molten metal does not entrain the air and the product forming part 1 ′ does not.
Filled in 0 '. Further, the decrease in the flow velocity of the molten metal is much smaller than when the valve tip 45 is moved by the pressure of the molten metal without using the valve spring 37 and the flow path is opened. Filling of the part is also easy.

As described above, when the molten metal flows, the contact portion 45c of the valve chip 45 is in close contact with the contact portion 50c of the valve guide 50. For this reason, the molten metal flows between the contact portion 45a of the valve tip 45 and the contact portion 42a of the nozzle base 42 and flows into the valve guide 50, but due to the close contact of the contact portions 45c and 50c as described above. Sliding part 45 between valve guide 50 and valve tip 45
b.

Thereafter, when the injection of the molten metal is stopped and the injection of the molten metal from the mechanical nozzle 4 is stopped, the connecting pipe 27 is connected to the pressure source 28 again, and the compressed air is sent into the pressure chamber 26 and the valve tip 45 Moves rightward in the figure as shown in FIG. Then, the contact portion 45a is again brought into close contact with the contact portion 42a of the nozzle base 42 and sealed, and
Close up.

On the other hand, the molten metal filled in the mold 22 is cooled and solidified there. As described above, since the molten metal does not flow in the vacuum and entrain the air, almost no cavities are generated inside the molded product. At this time,
The molten metal at the tip 21a of the nozzle tip 21 is also cooled and solidified. Thereafter, the movable die 22b moves in the direction of the arrow A (FIG. 1) to open the die 22, thereby integrating the product part 10a, the runner part 10b, and the gate part 10d as shown in FIGS. The molded article 10 is taken out. At this time, since the nozzle body 11 is heated by the heat from the mechanical nozzle, the sprue portion 8c is not formed as in the conventional molded product 8 shown in FIG.

As described above, when the molded article 10 is taken out, the temperature of the tip portion 21a of the nozzle tip 21 is rapidly restored to an appropriate temperature at which molding is possible by the heat of the central portion 11b of the nozzle body 11. If a material having good thermal conductivity is used for the nozzle body 11, it is possible to recover the temperature more rapidly.

At the time of the die casting, the molten metal tends to flow between the heat insulating ring 12 and the nozzle body 11.
The heat-resistant gasket 14 includes the heat insulating ring 12 and the nozzle body 11.
Is melted between the nozzle body 11 and the fixed mold 22a, so that the molten metal does not flow between the nozzle body 11 and the fixed mold 22a.

The temperature of the fixed mold 22a is much lower than the temperature of the molten metal.
The gap 17 (FIG. 2) with the heat insulating ring fitting portion 22ab can be made small, and the molten metal solidifies before flowing into the interior, so that the molten metal does not flow.

The gas supplied from the pressure source 28 may be not only air but also a gas capable of preventing metal oxidation.

FIGS. 15 and 16 are enlarged sectional views of a main part showing a modification in which a heater 18 is provided on the outer peripheral portion of the nozzle body 11 as a heating means for heating the nozzle body 11 in the embodiment shown in FIG. And a side view. The heater 18 has a temperature detection unit inside, and the nozzle body 1
The temperature control of 1 is performed. Reference numeral 18a denotes a lead wire of the heater 18, which is connected to a temperature control device (not shown). By providing the heater 18 in this manner, the temperature of the nozzle body 11 can be quickly raised to an appropriate temperature, and more efficient molding is facilitated. That is, the time for continuous molding can be extremely reduced. When the fixed mold 22a needs to be thickened and the nozzle main body 11 must be lengthened, it is particularly effective to provide a heating means such as a heater. Further, it is more effective to provide a heating means in the nozzle body for a die-cast metal material having a higher melting point.

In the modification shown in FIG. 15, a heat-resistant gasket 35 is further provided between the heat insulating ring 12 and the nozzle tip 21. The heat-resistant gasket 35 is formed between the concave portion 12 a of the heat insulating ring 12 and the tip 2 of the nozzle tip 21.
1a is sealed by being compressed between the nozzle tip 21 and the nozzle tip 21 and the screw portion of the nozzle body 11, which may be generated in the gap 34 between the fitting portion of the heat insulating ring 12 and the nozzle tip 21 due to the molten metal. Who is preventing.

In the valve chip 51 shown in FIG. 15, the contact portion 51a at the tip is formed in a spherical shape, and this contact portion 51a is formed in a conical contact portion 42a of the nozzle base 42.
The nozzle body 11 closes the flow path of the nozzle base 42 by being in close contact with the
This prevents the molten metal from flowing into the interior. The contact surface 51b of the valve chip 51 is also formed in a spherical shape, and the contact surface 51b is in close contact with the conical contact surface 50c of the valve guide 50, so that the molten metal flows into the pressure chamber when filling the molten metal. Is preventing. By making the contact portions 51a and 51b of the valve chip 51 spherical as described above, the valve chip 51 is moved to the nozzle base 4 due to play in the sliding portion between the valve guide 50 and the valve chip 51.
2 or even in a state of being inclined with respect to the valve guide 50, the flow path of the nozzle base 42 and the gap between the valve guide 50 and the valve chip 51 can be reliably sealed.

On the other hand, in the structure shown in FIG. 15, a gasket 52 made of a metal C-ring shown in FIGS. 20 and 21 is provided instead of the gasket 47 (FIG. 2) made of an O-ring fitted on the outer periphery of the heat insulating ring 12. ing. The gasket 52 is made of stainless steel, Inconel, Hastelloy, or the like, is positioned by a flange portion 12b provided on the outer periphery of the heat insulating ring 12, and is formed on the outer periphery of the heat insulating ring 12 and the inner periphery of the mounting hole 22d of the fixed mold 22a. Has been compressed between. Since the gasket 52 can further improve heat resistance as compared with an O-ring made of heat-resistant rubber or the like, even if the temperature of the molten metal is high and the temperature of the heat insulating ring 12 is high, the gasket 52 can be reliably sealed. .

Further, an annular groove 51e is provided on the outer periphery of the sliding portion 51c of the valve chip 51, and a metal C ring 56 is provided in the annular groove 51e. The metal C ring 56 is made of the same material and shape as the gasket 52. By providing the metal C-ring 56, even if the gap between the sliding portion 51c and the hole 50b of the valve guide 50 increases due to wear, it is possible to prevent air from flowing out of the pressure chamber 26, and The inflow of molten metal from the gap can also be prevented.

In this modification, a shut-off pin 49 which can be cooled is used. The shut-off pin 49 has a cooling water channel 49b in which the cooling water 36 flows. As shown in FIGS. 15 and 17 to 19, the cooling water flow path 49b is formed by partitioning the cavity in the shut-off pin 49 in the axial direction by the partition plate 49a, as shown in FIG. The cooling water 36 can be circulated through the upper and lower portions of the inside. By using such a cooling pin 49 which can be cooled, the molten metal filled in the product forming part 10 'is solidified, and the molten metal is released into the air escape groove 22ba.
Can be reliably prevented from flowing into the air. In addition, an annular concave portion 49c is provided on the outer periphery of the shut-off pin 49, and the O-ring 33 is housed therein.
Even if there is a large gap between them, the airtightness can be increased and the degree of vacuum in the product molded portion 10 'can be prevented from lowering.

In the valve chip 51 in FIG. 22, the contact portions 51a and 51b are both formed in a spherical shape.
The contact portion 42b of the nozzle base 42 and the contact portion 50c of the valve guide 50 that come into contact therewith are also formed in a spherical shape. As a result, the valve chip 51 is connected to the nozzle base 4
2 or even in a state of being inclined with respect to the valve guide 50, the flow path of the nozzle base 42 and the gap between the valve guide 50 and the valve chip 51 can be reliably sealed. Therefore, the nozzle body 11 is in a state close to a vacuum.
It is possible to prevent the molten metal from flowing into the inside, and to reliably prevent the molten metal from flowing into the pressure chamber when filling the molten metal.

Further, in the structure shown in FIG.
The heat insulating ring 55 is eliminated by integrating the nozzle tip 21 shown in FIG.
It has been modified so that it can be directly screwed onto the. In the structure shown in FIG.
8 or a metal C ring 52 can be used.

[0061]

According to the present invention, since the product forming portion of the mold and the nozzle body can be sealed and brought into a vacuum state, the inflowing molten metal does not entrain the air, and the cavity of the molded product can be reduced. Occurrence can be prevented. For this reason, it is possible to eliminate shape defects and surface treatment defects caused by the occurrence of cavities, and it is possible to significantly improve the quality of products.

Further, since the valve chip is moved by the elastic member to open the flow path, the flow velocity of the molten metal is not reduced as compared with the case where the flow path is opened by the molten metal, and the minute portion and the thin portion in the mold are reduced. The portion can be easily filled with the molten metal.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a vacuum forming apparatus for die casting according to one embodiment of the present invention is incorporated in a mold and attached to a die casting machine.

FIG. 2 is an enlarged sectional view of a main part showing a detailed configuration of the vacuum forming apparatus for die casting shown in FIG.

FIG. 3 is a partial detailed view of the vacuum forming apparatus for die casting shown in FIG. 2;

4 is an enlarged cross-sectional view of a main part showing a state when the inside of a product forming part and a nozzle body is evacuated in the vacuum forming apparatus for die casting shown in FIG. 2;

FIG. 5 is an enlarged sectional view of a main part showing a state when a molten metal is filled in the vacuum forming apparatus for die casting shown in FIG.

FIG. 6 is a side view of the melt forming side of the vacuum forming apparatus for die casting shown in FIG.

FIG. 7 is a side view of the vacuum forming apparatus for die casting shown in FIG. 2 on the molten metal inflow side.

FIG. 8 is a sectional view of the valve guide shown in FIG. 2;

9 is a side view of the valve guide shown in FIG. 8 on the molten metal inflow side.

FIG. 10 is a plan view of the valve guide shown in FIG.

11 is a side view of the valve guide shown in FIG. 8 on the molten metal injection side.

12 is a side view of the nozzle tip shown in FIG. 2 on the molten metal inflow side.

13 is a side view showing a molded product molded by the vacuum molding apparatus for die casting shown in FIG. 1 and the like.

FIG. 14 is a plan view of the molded product shown in FIG.

FIG. 15 is an enlarged sectional view of a main part showing a modification in which a heater is provided on the outer peripheral portion of the main body as a heating means for heating the nozzle main body in the embodiment shown in FIG. 2;

16 is a side view of the vacuum forming apparatus for die casting shown in FIG. 15 on the molten metal inflow side.

FIG. 17 is a front view of the blocking pin shown in FIG.

FIG. 18 is a sectional view of the blocking pin taken along line GG of FIG. 17;

FIG. 19 is a sectional view taken along line FF of the shut-off pin shown in FIG.

20 is a cross-sectional view of the metal C-ring shown in FIG.

FIG. 21 is a left side view of the metal C ring shown in FIG. 20;

FIG. 22 is an enlarged sectional view of a main part showing a modified example in which the shape of the contact portion between the valve tip and the valve guide shown in FIG. 15 is changed and the heat insulating ring is directly mounted on the nozzle body.

FIG. 23 is a sectional view showing a conventional die casting apparatus.

FIG. 24 is a side view showing a molded product formed by the die casting device shown in FIG. 23;

FIG. 25 is a sectional view showing a sprue bush used in the die casting apparatus shown in FIG. 23;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Melting furnace 2 Sleeve 3 Plunger 4 Mechanical nozzle 4a Molten metal injection part 5 Mechanical nozzle heater 6 Sprue bush 6a Mechanical nozzle touch part 7 Mold 7a Fixed mold 7b Movable mold 8, 10 Molded product 8a, 10a Product part 8b, 10b Runner Part 8c sprue part 8d, 10d gate part 8 ', 10' product forming part 9 molten metal 9a molten metal surface 11 nozzle body 12, 55 heat insulating ring 12a concave part 12b flange part 14, 29, 25, 43 heat resistant gasket 15 back plate 16, 44 Set screw 17, 34 Gap 18 Heater 18a Lead wire 20 Vacuum source 21 Nozzle tip 21a Tip 21b Screw 22 Die 22a Fixed 22b Movable 22aa Groove 22ab Insulation ring fitting 22ba Air escape groove 22bb, 22bc Air escape hole 23, 2 Guide ring 26 Pressure chamber 27 Connecting pipe 28 Pressure source 31, 36 Cooling water 32 Slot groove 33, 47 Gasket 35 Heat-resistant gasket 37 Valve spring 38 Lid 41 Nozzle body 41a Flange part 41b Screw part 41c Concave part 42 Nozzle base 42a Contact part 42c Mechanical nozzle touch part 42d Flange part 45 Valve tip 45a, 45c Contact part 45b Sliding part 48, 49 Shut-off pin 49a Partition plate 50 Valve guide 50a Projection part 50b Hole part 50c Contact part 50d Connection hole 50e Flow path 50f Through hole 50g, 50h recess 50i through hole 51 valve tip 51a, 51b contact part 51c sliding part 51e annular groove 52 gasket 56 metal C ring

Claims (13)

[Claims] A nozzle body, a nozzle tip fixed to the nozzle body, heat insulation between a mold, the nozzle body and the nozzle tip, and a position of the nozzle body in the mold and the metal mold. A heat-insulating ring fitted to the mold and the nozzle tip with a clearance fit; a compressible heat-resistant gasket provided between the nozzle body and the heat-insulating ring to prevent the passage of molten metal; and the heat-insulating ring and the mold. A gasket provided between the nozzle body and sealing to keep the product forming part of the mold in vacuum; and a valve provided movably in the nozzle body to open and close a flow path of the molten metal in the nozzle body. A tip, an elastic member for urging the valve tip in a direction to open a flow path of the molten metal in the nozzle body; and a valve tip formed in the nozzle body, and when the internal pressure increases, the valve tip is removed. A pressure chamber that urges the flow path in the nozzle body in a direction to close the flow path, a pressure source that adjusts a pressure in the pressure chamber, and a vacuum source that evacuates a product forming part of the mold. A vacuum molding apparatus for die-casting, wherein the valve chip is opened when the molten metal is injected, and the molten metal is poured from the flow path into the product molding section of the mold. 2. A nozzle body, which is fixed to the nozzle body, maintains heat insulation between the mold and the nozzle body, maintains the position of the nozzle body in the mold, and fits in the mold with a clearance fit. A heat-insulating ring that is provided between the nozzle body and the heat-insulating ring, and that is a compressible heat-resistant gasket that prevents the passage of molten metal; and a heat-insulating ring that is provided between the heat-insulating ring and the mold. A gasket that seals the product forming section to maintain a vacuum, a valve chip that is provided movably in the nozzle body, and that opens and closes a flow path of the molten metal in the nozzle body; An elastic member for biasing the flow path of the molten metal in the main body in a direction to open the flow path; and a valve chip formed in the nozzle body, which biases the valve tip in a direction for closing the flow path in the nozzle body when the internal pressure increases. Pressure chamber A pressure source that adjusts the pressure in the pressure chamber; and a vacuum source that puts the product molding portion of the mold in a vacuum state. The valve chip opens when molten metal is injected and opens from the flow path. A vacuum forming apparatus for die casting, wherein a molten metal is poured into a product forming section of a mold. 3. A heat-resistant gasket is provided between the heat insulating ring and the nozzle tip.
The vacuum forming apparatus for die casting according to the above. 4. The vacuum forming apparatus for die casting according to claim 1, wherein a heat-resistant metal material having a higher thermal conductivity than heat-resistant steel is used for the nozzle body and the nozzle tip. 5. The nozzle body is made of a heat-resistant metal material having better thermal conductivity than heat-resistant steel.
The vacuum forming apparatus for die casting according to the above. 6. The valve tip has a conical first contact portion, and the nozzle body has a conical contact portion at a portion where the first contact portion of the valve tip contacts. The vacuum forming apparatus for die-casting according to claim 1, 2, 3, 4, or 5. 7. The valve tip has a spherical first contact portion, and the nozzle body has a conical contact portion at a portion where the first contact portion of the valve tip contacts. The vacuum forming apparatus for die casting according to claim 1, 2, 3, 4, or 5. 8. The valve tip has a spherical first contact portion, and the nozzle body has a radius that is the same as or slightly larger than the first contact portion at a portion where the first contact portion of the valve tip contacts. 6. The vacuum forming apparatus for die casting according to claim 1, further comprising a spherical contact portion having the following shape. 9. The nozzle body is provided with a valve guide that guides the valve tip and forms the pressure chamber, the valve tip has a second conical contact portion, and the valve guide is 9. The vacuum forming apparatus for die casting according to claim 1, wherein the valve chip has a conical contact portion at a portion where the second contact portion contacts. 10. The nozzle body is provided with a valve guide that guides the valve tip and forms the pressure chamber, the valve tip has a spherical second contact portion, and the valve guide is provided with the valve. The vacuum forming apparatus for die casting according to any one of claims 1, 2, 3, 4, 5, 6, 7, and 8, wherein a portion where the second contact portion of the chip comes into contact has a conical contact portion. 11. The nozzle body is provided with a valve guide that guides the valve tip and forms the pressure chamber, the valve tip has a spherical second contact portion, and the valve guide is provided with the valve. 6. The chip according to claim 1, wherein a portion of the chip contacting the second contact portion has a spherical contact portion having a radius equal to or slightly larger than the second contact portion. 9. The vacuum forming apparatus for die casting according to 6, 7, or 8. 12. The nozzle body is provided with a valve guide for guiding the valve chip and forming the pressure chamber, and a metal C-ring is provided on a sliding portion where the valve chip and the valve guide slide. The vacuum forming apparatus for die casting according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11. 13. The nozzle body according to claim 1, further comprising a heating means capable of controlling the temperature.
The vacuum forming apparatus for die-casting according to 5, 6, 7, 8, 9, 10, 11 or 12.