JPH0237488Y2 - - Google Patents

Description

[Detailed description of the invention] "Purpose of the invention" The present invention relates to a low-pressure casting device using ceramic stalks.・The aim is to provide a low-pressure casting device that can eliminate damage to the stalk, prevent gas entrainment in the cast body, and smoothly cast good products, and has a simple configuration and excellent durability. be.

(Industrial application field) Equipment that casts molten metal such as molten aluminum under low pressure conditions.

(Prior art) When casting molten aluminum, etc., the molten metal in a sealed holding furnace is heated by high pressure air acting on the surface of the molten metal through a stalk inserted from the top. A low-pressure casting method for press-fitting into a mold has been known for a long time. That is, the stalk is made of cast iron, and this cast iron stalk has high strength, is less likely to be damaged, and can be connected in an airtight manner using packing material.

In order to avoid the above-mentioned disadvantages of cast iron stalks, in Utility Model No. 108461/1984, the mold was received on the lower die base, and the flange part of the ceramic stalk was held by the stalk ring through a sealing material held in the seal ring. It is proposed to fasten with metal fittings.

The inventors of the present invention also proposed a low-pressure casting device using a ceramic stalk in Japanese Utility Model Application Publication No. 62-72760, and by using such a ceramic stalk, molten aluminum can be cast when a cast iron stalk is used. It is possible to prevent Fe contamination or coating mold contamination due to contact with the paint, and to appropriately control quality.

(Problems to be solved by the invention) The above-mentioned Utility Model Application No. 60-108461 and the proposal proposed by the inventor of the present invention can avoid molten metal contamination when conventional general cast iron stalks are used. −
In the case of 108461, the weight of the upper and lower molds is supported by a large lower die base installed on the furnace lid, making the equipment large and requiring stalk rings to be installed above and below the stalk flange, making it complicated. Therefore, the flange portion needs to be tightly fixed to the stalk ring.
On the other hand, in the method proposed by the present inventors in 1987-72760, the weight of the mold was not supported by the lower die base as described above, but instead the flange formed on the ceramic stalk was supported by upper and lower protective fittings. Although this simplifies the equipment, the stalk flange is hermetically sealed and fixed to the protective metal fitting as described above, and the ceramics that are tightly fixed and sealed at the flange in this way are According to the results of actual pouring operations using the stalk, there was significant damage near the flange. In other words, such a flange part is 500~
The temperature reached a high temperature of 750℃, and the molten metal that had been rising inside the stoke under such high-temperature conditions suddenly fell into the holding furnace after solidifying at the nozzle of the mold, causing considerable vibration or rocking to the stoke. The forces caused by these vibrations and swings act intensively on the flange portion, which is firmly sealed under pressure, resulting in cracks and damage in the flange portion. Even if such a problem can be covered to some extent by providing a sheath to the stalk, cracks are likely to occur, and the flange cannot be tightly sealed to avoid the occurrence of such cracks. However, as a result of not being able to securely tighten the stalk flange, the gas in the holding furnace passes through the packing against the stalk flange, passes through the protective fittings, passes through the packing on the upper part of the stalk flange, and is drawn into the molten metal, causing the cavity to become engulfed. The cast product inside becomes defective.

"Structure of the invention" (Means for solving the problem) Molten metal in a holding furnace sealed by a lid is connected to a mold above the lid via a ceramic stalk, and acts on the surface of the molten metal. A stalk protection fitting that seals the entire flange formed on the ceramic stalk via a stalk holding material that does not form a complete seal, in a device in which the molten metal is press-fitted into a mold by gas pressure for casting. a vent is formed between the holding material of the stalk protective fitting and a stalk holding material interposed on the upper surface of the flange portion, and the mold is supported by the protective fitting via an intermediate stalk. A low-pressure casting device using ceramic stalks, which is characterized by:

(Function) Contamination of the molten aluminum supplied into the mold cavity is avoided by press-fitting the molten metal into the mold using a ceramic stalk and casting.

The entire flange formed on the ceramic stalk is received in a sealing stalk protection fitting, thereby appropriately reinforcing the flange. By supporting the mold by setting it on the lid of the holding furnace through the reinforced stalk protection fitting and the intermediate stalk, this type of casting equipment can be made extremely simple and compact, and the load of the mold is transferred to the flange of the stalk. This prevents damage to the parts by avoiding concentrated action on them. By holding the space between the stalk flange portion and the holding fitting with a stalk holding material that does not form a complete seal, the acting force due to vibrations caused by the flow of molten metal descending inside the stalk after pouring into the mold is prevented from being concentrated on the flange portion. prevent damage near the flange of the stalk. By forming a ventilation section for the outside air in the space formed between the stalk holding material and the packing interposed on the upper surface of the flange part, it is possible to operate under the conditions of sealed support and connection by the stalk protection fittings as described above. Under the setting conditions of the stalk holding material that maintains the space at atmospheric pressure conditions and does not form a complete seal, the positive pressure gas on the surface of the molten metal in the holding furnace when the molten metal rises in the stalk does not enter into the molten metal rising in the stalk. Precisely prevent

(Example) An embodiment of the present invention shown in the attached drawings will be described.The general structure thereof is as shown in FIG. Insert into the molten metal 11 in the furnace,
The stalk 3 communicates with a mold 15 consisting of a lower mold 15b and an upper mold 15a, and the molten metal 11 is press-fitted into the mold 15 under the pressure of air or an inert gas such as nitrogen or argon through a high-pressure gas pipe 16 for casting. The process itself is the same as the conventional method described above, and a ceramic stalk is used as the stalk 3,
A flange portion 5 having a protrusion width approximately 1/2 to 2 times the wall thickness of the stalk 3 and a height approximately 1 to 5 times the protrusion width is formed on this. On the other hand, the flange portion 5 is made of cast iron or the like.
Flange protection fittings 1a, 1b are attached above and below to seal the flange protection fittings 1a, 1b, and stalk retainers 7, 8 which do not form a complete seal are interposed for these protection fittings 1a, 1b, respectively, and a connecting means 9 is used to connect both protection fittings 1a, 1b. Connect 1b. In addition, in this illustrated example, an intermediate stalk 14 is connected to the protective fitting 1a via a sealing material 4a, and the intermediate stalk 14 communicates with the mold 15. However, as described above, the protective fitting 1
A ventilation section 6 for the outside air is formed in the protective metal fitting 1a or 1b between the upper and lower stalk holding members 7 and 8 interposed between the support joints a and 1b and the flange portion 5.

As the stalk holding members 7 and 8 described above, it is preferable to use members such as flexible heat-resistant packing, and as the sealing material 4a, in addition to the flexible heat-resistant packing described above, metal packing materials can be widely used. Can be adopted. In the embodiment shown in FIG. 1, there is a possibility that the stalk retaining material 7 is blocked by contacting the molten metal and does not form a complete seal, but the stalk retaining material 8 ensures that it does not form a complete seal. It is clear that it can be done.

The ventilation portion 6 described above is not only opened at the side surface of the lower protective fitting 1b as shown in FIG. 2, but also opened at the boundary of the upper protective fitting 1a as shown in FIG. The boundary surface portion of the metal fitting 1b can be formed so as to intersect with the boundary surface between the two protective metal fittings 1a and 1b, as shown in FIG. Note that the ventilation portion 6 is provided with the protective fitting 1a or 1 as shown in FIG. 6A.
They can be formed by crossing one or both of them, or they can be formed in a cross-like relationship as shown in FIG. In the case where a plurality of ventilation portions 6 are formed in this manner, outside air is introduced and circulated around the flange portion of the stalk 3 under the condition that the entire flange portion 5 is sealed and reinforced as described above, and the ceramic stalk is heated. Appropriate cooling effect can be given to the flange part. Also, in order to achieve this kind of relationship, instead of forming ventilation parts 6 such as holes or grooves in the protective metal fittings 1a and 1b, the ventilation parts 6 are provided in packing 17 that is separately prepared on the joint surfaces of these protective metal fittings 1a and 1b. This is also possible by assembling the parts as shown in FIG. 5D. Furthermore, as described above, the structure according to the present invention does not form a perfect compression seal in the stalk holding members 7 and 8, and together with the cooling effect as described above, the durability thereof is increased.

In the above description, the protective metal fitting 1 is divided into upper and lower parts, and the protective metal fittings 1a and 1b are used. However, the protective metal fitting 1 according to the present invention may be integrally molded as shown in FIG. That is, the protective metal fitting 1 supported by the lid part 2 forms a support part that completely receives the flange part 5 of the stalk 3, and the intermediate stalk 14 is set on the protective metal fitting 1 that is integrated with the flange part 5. In this case, the stalk holding member 7 and the connector 9 are omitted, and the sealing material 4a interposed between the intermediate stalk 14 and the protective fitting 1 also serves as packing between the intermediate stalk 14 and the protective fitting 1. The ventilation portion 6 is opened between the sealing material 4a and the stalk holding material 8, and the stalk holding material 8 in this case does not come into contact with the molten metal. Note that in the case shown in FIG. 4, the protective metal fitting 1 may be divided in the vertical direction, and in this case, the ventilation portion 6 can be formed between the joint surfaces of the vertically divided protective metal fittings.

In the device according to the present invention as described above, the flange portion 5 of the ceramic stalk 3 is properly reinforced by the protective metal fitting 1 and suspended from the lid portion 2, so that the entire load of the intermediate stalk 14 and the mold 15 is absorbed. It can act on the flange 5 portion of the stalk 3, effectively preventing cracks from occurring in the stalk 3, and eliminating the need for a large base member or the like for supporting the mold 15 on the holding furnace or lid. do.
Furthermore, when the molten metal 11 in the furnace is press-fitted from the stalk 3 into the mold 15 in such a state, even if the sealing performance of the holding members 7, 8 or 4a decreases due to the rise in temperature of the stalk 3, the molten metal cannot be inserted into the mold 15. When the pressure inside the holding furnace 10 is increased to pressurize the holding furnace 15, when positive pressure gas enters the space 12 of the protective fitting 1 from the lower stalk retaining material 8 portion, it is released to the outside air from the ventilation portion 6, and the upper stalk retaining material 15 is pressurized. This positive pressure gas is accurately prevented from entering the stalk 3 from the packing 4a or the stalk holding member 8. That is, space 1
The inside of the holding furnace 10 is always at atmospheric pressure, and the molten metal rising inside the stoke 3 is under positive pressure, and the pressure is higher than that inside this space 12. Therefore, the positive pressure gas inside the holding furnace 10 exceeds the space 12. It never enters the stalk 3 from the holding packing 7 or the packing 4a and enters the cavity. Moreover, mold 1
After the molten metal is completely poured into the stoke 5 and the nozzle part is solidified, the flange part 5 is caused by the vibration of the stoke 3 when the molten metal in the stoke 3 descends into the holding furnace. Since the flange is not completely sealed, the vibrations are effectively absorbed and no damage occurs near the flange. Note that this working relationship is such that when the sealing performance of the upper stalk retainer 7 or packing 4a deteriorates or changes due to intrusion of molten metal, the molten metal rising into the cavity is always under positive pressure, so the stalk retainer 7 portion The same result can be obtained since there is no possibility of gas intrusion into the rising molten metal from the outer periphery and the performance of the holding material 7 or 8 is maintained.

Furthermore, as mentioned above, since the stalk retaining members 7 and 8 do not form a perfect sealing relationship in the present invention, there is no need for sufficient tightening using the connectors 9, etc., and there is a certain amount of leeway. Since a tightening seal is sufficient, each holding material 7,
Aging or fatigue in parts such as No. 8 is eliminated, and in any case, a highly durable device is obtained with a simple and compact configuration.

(Effects of the invention) According to the invention as explained above, a ceramic stalk is used to avoid molten metal contamination, and to reduce the load caused by a mold, etc. that acts on the flange of the ceramic stalk, which is a fragile body, from the flange. The overall structure is effectively avoided and reinforced by the hermetically sealed stalk protection fitting, and the load of the mold, etc. is supported by the stalk protection fitting, making it possible to simplify and compact the entire device. Since the stalk retaining material interposed between the stalk protection fitting and the stalk flange does not form a complete seal, there is no need for large tightening, and it is effective against vibrations when the molten metal falls inside the stalk. This is because it prevents damage to the ceramic stalk from any of these factors, increases the durability of the packing, and provides favorable durability to the entire device despite its simple and compact structure. This is a highly effective idea industrially.

[Brief explanation of the drawing]

The drawings show the technical contents of the present invention, and Fig. 1 is a cross-sectional explanatory view of the entire device according to the present invention, Fig. 2 is an enlarged sectional view of the ceramic stalk attachment part, and Fig. 3 is an illustration of the device. A cross-sectional diagram showing the working relationship when the molten metal rises in the stalk in the ventilation section,
FIG. 4 is a sectional view of another embodiment of the present invention, and FIG. 5 is a side view showing a modification of the ventilation section.
FIG. 6 is a plan view showing a modification of the arrangement of the ventilation section. In these drawings, 1a and 1b are stalk protection fittings for sealing the flange portion, 2 is a lid portion, 3 is a ceramic stalk, 4 is a sealing material, 5 is a flange portion of the stalk, 6 is a ventilation portion, 7, 8 is the stalk holding material, 9 is the connector, 10
11 is a holding furnace, 11 is a molten metal, 12 is a space, 14 is an intermediate stalk, 15 is a mold, 15a is an upper mold thereof, 15
16 is a high pressure gas pipe, and 17 is a packing.

Claims (1)

[Scope of utility model registration request] The molten metal in the holding furnace sealed by the lid is connected to the mold above the lid via a ceramic stalk, and the molten metal is forced into the mold by gas pressure acting on the surface of the molten metal and cast. The flange portion formed on the ceramic stalk is received by a stalk protection fitting that seals the entire flange portion via a stalk holding material that does not form a complete seal, and the holding material of the stalk protection fitting and the flange portion A ventilation section for outside air is formed between the stalk holding material interposed on the upper surface of the
A low-pressure casting apparatus using a ceramic stalk, characterized in that the mold is supported by the protective fitting via an intermediate stalk.