JP4789241B2 - Tire mold casting method - Google Patents

Description

  The present invention relates to a method for casting a tire molding die. More specifically, the present invention relates to a technology capable of producing a ring casting for a tire mold with a quality and cost equal to or higher than those of the low pressure casting method using the gravity casting method.

  Tire molding dies are divided into two-piece molds (upper and lower molds) that divide the tire shape into two in the width direction, and 7 to 13 in the radial (circumferential) direction. There are two types of molds (upper and lower integrated type). Since these dies have many shapes that are difficult to deal with by machining (concave blocks with sharp corners, thin convex shapes called sipe blades), they may be manufactured by a casting method. Many.

  It can be said that the gypsum casting method is often used among casting methods. This is because the mold is collapsible, has a high degree of freedom in supporting undercut shapes, can be easily assembled with the mold, can be cast into a nearly integral shape, and has high dimensional accuracy. The reason is that the mold cost is low.

  In order to manufacture tire molds by the gypsum casting method, known procedures such as prototyping, rubber mold reversal, gypsum mold reversal, mold drying and angle cutting, ring-shaped mold assembly, casting, mold separation, and mold matching are used. Done. Among the above processes, the casting process is the most important process in which a gypsum mold casting and a casting frame are assembled on a surface plate in a ring shape to pour molten alloy. Conventionally, various casting methods are known for pouring molten metal into a mold.

  FIG. 1 is called a gravity casting method, which is a method of pouring molten metal from a position higher than the casting frame / mold position, and the falling molten metal is often rectified at the gate and runner. There is an advantage that it is easy to carry out casting of relatively large objects without requiring a large-scale device, but when the molten metal falls during pouring, air (bubbles) is entrained in the molten metal or oxynitride is generated. There is also a drawback that casting defects are likely to occur due to this.

  Fig. 2 is called the overturning casting method (Darville method). The casting frame and mold are connected to a hot water reservoir (one side open container where molten metal is stored), and the initial state is lower than the casting frame and mold. This is a method in which the molten metal is poured into the casting frame and mold by tumbling the casting frame and mold and the hot pool after setting and pouring the molten metal into the hot pool. The casting completion time can be made the fastest, and it is easy to carry out casting of relatively large items with the equipment, but it is inevitable that the molten metal will fall during pouring, so it is difficult to avoid the occurrence of casting defects. is there.

  Fig. 3 is called the suction casting method (CLA process). The molten metal is placed at a position lower than the position of the casting frame / mold and the inside of the casting frame / mold is decompressed to suck the molten metal into the casting frame / mold. It is a method of pouring hot water. There is an advantage that there is little bubble entrainment and oxynitride generation during pouring, and it is difficult to cause casting defects due to this, but the mold must have air permeability, a vacuum suction device is also essential, and There is a drawback that it is difficult to handle.

  Fig. 4 is called the low pressure casting method. The molten metal (hot water reservoir) is placed at a position lower than the casting frame / mold position, and the molten metal is swelled through the hot water pipe by pressurizing the hot water reservoir. This is a method of pouring molten metal into the mold. There are advantages such as less bubble entrainment and oxynitride generation during pouring, less prone to casting defects due to this, and the ability to cast without hot water, but there is a dedicated casting device (low pressure casting device). It is indispensable and has the disadvantage that it is difficult to cast large items and dense alloy types.

  Fig. 5 is called the die-casting method. The molten metal (plunger) is placed at a position lower than the casting frame / mold position, and the molten metal springs up through the hot water supply pipe by pressurizing the molten metal into the casting frame / mold. It is a method of pouring hot water. It is a mass production method that uses “steel” as the mold and produces multiple castings in the same mold early in the cycle. The cast structure is easy to refine (the mold is made of steel, so the molten metal from the mold can be solidified and cooled quickly). There is an advantage that casting without the hot water is possible, but a dedicated casting device (die-casting machine) is essential, and if the casting speed is excessively increased, there is a possibility of casting defects due to bubble entrainment or oxynitride. There are drawbacks in that it tends to occur and the casting of an undercut product is difficult because the mold cannot be broken.

  When the above conventional casting methods are classified according to the types of alloys that can be cast, the gravity casting method, the falling casting method, and the suction casting method have relatively high melting points (casting temperatures) such as precious metals, copper alloys, nickel alloys, and iron-based alloys. Almost all practical alloy materials, including high and high-density alloy types, can be cast, while the low-pressure casting method and die-casting method have relatively low melting points such as zinc alloy, magnesium alloy, and aluminum alloy. It has the advantages and disadvantages that only low alloy grades (so-called light alloys) can be cast.

  Each of these casting methods (pouring methods) always has “defects”, so the optimum casting method must be selected for each property to be cast. There were some properties that could not be cast with high yield. More specifically, this is a property that has a large casting weight (for example, a property that exceeds 1000 kg) and that does not allow for casting defects. Although it can only be said that the casting method is used, there has been a problem that the occurrence of casting defects cannot be completely suppressed and defects are frequently generated.

  When the molten metal falls, entraining bubbles or forming oxynitrides is the same phenomenon as entraining air bubbles when water is poured into a cup from a tap. That is, the longer the distance from the opening surface of the faucet to the bottom surface of the cup and the greater the flow rate of water per unit time from the faucet, the more air bubbles will be involved. In the case of casting, not only entraining air bubbles but also combining non-metallic inclusions (oxynitride, slag, dross) at the same time by combining (oxidizing / nitriding) the substance in the molten metal and atmospheric components. Become. If these bubbles and non-metallic inclusions stick to the surface of the casting frame / mold, or stay in the casting product part, they are likely to cause a problem as a “casting defect”.

  As described above, there are various casting methods, but as a method for pouring a ring casting for a tire mold, there are many cases where two methods of a gravity casting method and a low pressure casting method are adopted. In the gravity casting method, a bubble is trapped in the molten metal and oxynitride is formed as much as possible due to a drop during pouring. In many cases, it is necessary to install a gate, a runway, and a weir to float and separate this. Further, in the low pressure casting method, when the molten metal is cast without being transferred from the melting furnace, bubbles can be entrained and oxynitride formation can be performed with a minimum. However, since the molten metal is exposed to a pressurized gas atmosphere, there is a risk of generating hydrogen pinhole defects in the casting if the moisture is high in the pressurized gas.

  FIG. 6 is a view for explaining a known technique when a ring casting for a tire mold is manufactured by a gravity casting method. A gypsum mold 2 that has been separately assembled on a surface plate 1 is installed, and a cast is formed thereon. Place frame 3. A cast frame 4 having a gate, a runner, and a weir structure is placed on the outside, and a runner and a weir structure are formed by the surface plate 1 and the cast frames 3 and 4. A cooling metal 5 is disposed on the lower surface of the casting frame 3. The surface plate 1 also functions as a cooling metal. The pouring method shown in FIG. 6 is described in Non-Patent Document 1.

  FIG. 7 is a view for explaining a known technique when a ring casting for a tire mold is manufactured by a low pressure casting method. The gypsum mold 2 is assembled on a gypsum surface plate 6 and the gypsum mold 7 is assembled on a gypsum runner board 7. Install to make superstructure. This is set on the pressurizing furnace 8 and the molten metal is pushed up and poured through the runner board 7. The pouring method of FIG. 7 is described in Patent Document 1.

  The above-mentioned gravity casting method has the advantage that it is easy to dispose cooling metal on both the upper and lower sides of the ring casting (it is easy to aim at simultaneous solidification / cooling of the molten metal from the upper and lower sides of the casting). The “disposable structure” has the disadvantage that it must be remade every time one ring is cast. The low-pressure casting method has the advantage of minimizing bubble entrainment and oxynitride formation, but it is difficult to place cooling metal on the lower side of the ring casting (only the pattern of molten metal solidification / cooling from the upper side to the lower side) In addition, the gate, runner, and weir structure is a “disposable structure” and has the disadvantage that it must be remade every time one ring is cast.

  In casting using a gypsum mold, since the thermal conductivity of the gypsum mold material is low, the possibility that the cast molten metal spontaneously solidifies and cools from the gypsum side is extremely low. For this reason, sound castings with few shrinkage defects are often produced by using a casting frame or surface plate as a “cooling metal” and directional solidification of the molten metal from the side of the casting frame or surface plate. Therefore, it is no exaggeration to say that the arrangement structure of the cooling metal determines the internal quality of the microstructure of the ring casting for tire mold. (If the molten metal solidifies and cools slowly, the microstructure becomes coarse, and it is easy to cause problems such as the formation of fine shrinkage cavities and the deterioration of strength characteristics. There is also a problem that it is directly related to the difference in dimensional characteristics of

From this point of view, as described above, it can be said that the gravity casting method is superior to the low-pressure casting method in that the cooling metal can be placed on the upper and lower sides of the casting, so that the degree of freedom in arranging the cooling metal is high. (In the low-pressure casting method, the lower structure is completely embraced by the casting, and the molten metal is pressurized and replenished to the end of the solidification of the product part through the runner and weir by pressurization in the furnace. It is difficult to place cooling metal because there is a restriction that it has to be.) However, even with gravity casting, if excessive cooling metal is placed on the upper and lower sides, the flow of hot water during pouring can be secured. There will be a problem that it does not exist or obstructs the hot water supply effect to the product part. Therefore, strict control of the arrangement of the cooling metal is indispensable, but in the conventional method, this control is difficult. (Lower side; surface plate side; the molten metal tends to flow, but after the pouring is complete, it is necessary to exert a sufficient cooling metal effect. On the upper side, the molten metal does not interfere with the hot water replenishment effect. It is necessary to adjust the contact area with the molten metal, but there was no good method that can be easily fine-tuned for each property to be cast.)
In this way, there are advantages and disadvantages for each, and a satisfactory casting method has not been established in all respects.
Japan Foundry Engineering Society "Casting Engineering" Vol.75, No.10, pp.682-687 JP 57-58968

  The present invention has been invented under such circumstances, and the first object thereof is that the sprue, runner, and weir structure is a disposable structure common to the above-described conventional gravity casting method and low pressure casting method. An object of the present invention is to provide a method for casting a tire mold that solves the drawback of having to be remade each time a ring is cast and enables reuse. A second object is to provide a technique capable of easily and accurately controlling the amount of cooling metal disposed, which is essential when manufacturing a ring casting for a tire mold by a gypsum casting method. A third object is to provide a technique capable of casting without a hot water even when a gravity casting method is used.

  In order to solve the above-mentioned problems, the invention of claim 1 is directed to a casting composition made of a material that does not melt or collapse with a molten alloy to be cast when a ring casting for a tire mold is manufactured by a gravity casting method. A ring-shaped groove shape with an inner surface that is slightly larger than the outer diameter of the ring casting is engraved on the board, and a hollow ring with a shape that can be capped on it is vertically aligned. It is characterized by being able to repeatedly use the gate, runner, and dam structure by forming a gate, runner, and dam structure by attaching a heat insulating material to the inner surface of the groove shape. .

  As in claim 2, a circular counterbored groove is formed in the center of the casting surface plate, and a detachable surface plate that can be detached is prepared separately, and a ring mold is placed on the surface plate. Therefore, it is preferable that the mold assembly and re-drying operations and the heat insulating material affixing operations on the pouring gates, runners and weir structures of the casting surface plate can be performed independently.

  In addition, as described in claim 3, a desorption surface plate and a casting surface plate are used as the cooling metal on the lower side of the mold, and a casting frame installed immediately above the mold is used as the cooling metal on the upper side. A heat insulating material is pasted, and by disposing a plurality of discontinuous openings in this heat insulating material, the cooling metal efficiency is adjusted by adjusting the opening ratio, and there is almost the same cooling metal effect on the upper and lower sides. At the same time, it is preferable to ensure the hot water flow during pouring.

  Further, as in claim 4, a donut-shaped closed space is formed by a casting platen, a hollow ring, and a casting frame that covers the mold, and after pouring is completed, the molten metal is pressurized from the open surface side of the pouring gate, It is preferable to use the molten metal in the runner as a hot water.

  According to the first aspect of the present invention, a plurality of ring castings can be used without engraving a runner and a weir structure, which have been conventionally made in a casting frame (sand mold), on a surface plate (steel material, etc.) and making it disposable. Can be used for casting. According to the second aspect of the present invention, the weak point in the first aspect of the present invention that the casting surface plate must be made slightly larger than the casting can be solved. According to the invention of claim 3, it is possible to arbitrarily adjust the cooling metal efficiency. According to the invention of claim 4, the hot water can be minimized. For this reason, if this invention is used, the ring casting for tire molds of good quality can be cast-manufactured more easily and cheaply than the conventional method. The present invention overcomes the weaknesses of the conventional gravity casting method and the low pressure casting method, and provides an optimum casting method in which only the advantages are fused, and has a great technical significance. Preferred embodiments of each invention will be described below.

(Invention of Claim 1)
FIG. 8 is an exploded perspective view showing an embodiment of the invention of claim 1, and FIG. 9 is a cross-sectional view showing a case where a ring casting for a tire mold is manufactured by a gravity casting method. Reference numeral 10 denotes a casting surface plate made of a material that does not melt or collapse with the molten alloy to be cast, and a ring-shaped groove 11 having an inner diameter that is slightly larger than the outer diameter of the ring casting to be cast on the upper surface. Carved in an open structure. The ring-shaped groove 11 is a portion corresponding to a runner, but the gate groove 12 and the weir groove 13 are also continuously carved into the ring-shaped groove 11.

  A heat insulating material 14 such as ceramic paper is attached to the inside of the ring-shaped groove 11, the gate groove 12, and the weir groove 13, and a ring-shaped heat insulating material 15 is laid on the entire upper surface of the heat insulating material 14. As shown in FIG. 9, a gate 18, a runner 19, and a weir structure are assembled by vertically assembling a hollow ring 16, 17 having a shape capable of covering the top and bottom. 20 is formed. As the material of the casting surface plate 10, various steel materials and nickel alloy materials are preferably used. A so-called “heat-resistant material” is preferable, but when an aluminum alloy casting is assumed, a general steel material can be used sufficiently. The casting surface plate 10 may be provided with a forced cooling mechanism from the outside. In this case, a copper alloy can be used as the surface plate material.

  A gypsum mold 2 assembled in a ring shape is set in the center of the casting surface plate 10, and a casting frame 21 is placed on the upper part thereof. In addition, the diameter of the spout 18 is narrowed down with the gypsum cell 22, but the reason is 1) In order to float and separate the entrained bubbles during pouring inside the chute, 2) The height of the chute and the cross-sectional area of the relevant part, In order to control the upper limit value of the pouring flow rate per unit time, 3) to make this part easy to break during mold disassembly described later.

When the molten alloy is poured from the gate 18 in the state of FIG. 9, the molten alloy travels around the entire circumference through the ring-shaped runner 19, and the space between the gypsum mold 2 and the hollow rings 16, 17 from the weir structure 20. It flows into and solidifies. The subsequent mold separation procedure is as follows.
1) Chute demolding (breaking the cast reducer with gypsum cell and removing the chute)
2) Casting frame removal
3) Hollow ring demolding
4) Demolding the ring casting from the casting surface plate (demolding the insulation board with the weir structure)
5) Breaking and removing runners and weirs from ring castings

  In this method, it is inevitable that the melt of the chute portion and the runner portion becomes a sandwich of the hollow ring 16. One point is how to deal with this part at the time of mold separation. In FIG. 9, this is dealt with by “breaking” one side of this portion, but other methods may naturally be adopted.

The following points should be noted when taking such a mechanism.
1) Keep the hot water tap 18, the runway 19 and the weir structure 20 warm and insulated so that the molten metal in the runway 19 does not solidify until the pouring is completed. Since the material of the casting surface plate 10 is “metal material” and the thermal conductivity is high, it is essential to attach the heat insulating material 14 to the inner surface of the groove.
2) Create a groove structure that allows for "type breaks" after casting. For example, as shown in FIG. 9, a contrivance is made such that a groove shape with a draft is formed on the upper surface of the casting surface plate 10, and a portion where the draft is reversed is not created.
3) The affixing of the heat insulating material 14 to the casting surface plate 10 is not necessarily “adhering”. It is more preferable to have a structure in which the heat insulating material 14 is fitted without being bonded. (To reduce the preparation man-hours for the surface plate and prevent molten metal contamination during casting.)
By doing in this way, even when the gravity casting method is used for manufacturing the ring casting for the tire mold, it is possible to cope without making the gate 18, the runner 19 and the dam structure 20 disposable.

(Invention of Claim 2)
In the invention of claim 1 described above, the basic structure of the gate 18, the runner 19 and the weir structure 20 is previously formed as a groove shape in the casting surface plate 10 so that it can be used repeatedly. It also has a weak point that the platen 10 must be made slightly larger than the casting. In particular, when gypsum material is used as the mold material, pinhole defects may occur in the casting due to moisture absorption from the atmosphere, so the gypsum mold 2 assembled in a ring shape is re-dried until just before casting ( Often secondary drying). Since the secondary drying of the mold is usually performed in an external heating type heating furnace, it is necessary to put the platen in which the mold is assembled into the heating furnace. If the surface plate is too large, the secondary drying is performed. The heating furnace required for this is also required to be large, and a large capital investment is required. Claim 2 is for solving this problem.

  Therefore, in the invention of claim 2, as shown in FIG. 10, a circular counterbore groove 30 is formed in the center of the casting surface plate 10, and a detachable surface plate 31 of a form that can be detached is separately manufactured, and during casting, By mounting the ring-shaped gypsum mold 2 on the detachable surface plate 31, the mold assembly and re-drying operations and the operation of attaching the heat insulating material to the gate 18, the runner 19 and the dam structure portion 20 of the casting surface plate 10 are independent. I was able to do it. That is, only the desorption surface plate 31 and the gypsum mold 2 may be put in the heating furnace and secondarily dried, and the large casting surface plate 10 need not be placed in the heating furnace.

(Invention of Claim 3)
In the previous case, the installation of the cooling metal to the casting is as shown in FIG. That is, the rear side casting frame C part, the upper casting frame B part, and the surface plate A part are utilized as cooling metal. In view of the soundness of the microstructure of the casting, the uniformity between the upper and lower molds, and the dimensional difference between the upper and lower molds, it can be said that it is desirable that the A part and B part have approximately the same large cooling effect. However, if the chilling effect of part A is excessively increased, the molten metal solidifies during pouring, and there is a case where the molten metal filling the casting frame is hindered. The invention of claim 3 is for solving this problem.

  Therefore, in the invention of claim 3, the desorption surface plate 31 and the casting surface plate 10 are used as the cooling metal on the lower side of the mold, and the casting frame 21 installed immediately above the mold is used as the cooling metal on the upper side. By attaching a heat insulating material 40 having a plurality of discontinuous openings arranged on the contact surface, the cooling efficiency is adjusted by adjusting the opening ratio, and at the same time, an approximately equivalent cooling effect is provided on the upper and lower sides. Also ensure hot water flow during pouring. Specifically, as shown in FIG. 12 and FIG. 13, “insulation material with punched holes” (punching insulation material) 40 is pasted on the surface of the casting frame that is in contact with the molten metal as cooling metal, and the opening ratio of the insulation material 40 Cooling efficiency is controlled by (area%) so that the maximum cooling effect can be achieved within a range that does not hinder hot water flow during pouring.

  The invention of claim 3 can adjust the cooling metal efficiency arbitrarily even if a large cooling metal is used, and can easily adjust the opening ratio of the hole to the heat insulating material 40. It's a method. In the above schematic diagram, only the A part and the B part are explained, but it may naturally be used for the C part. Moreover, after the pouring operation is completed, the casting frame and the surface plate of the corresponding part can be forcedly air-cooled or forced water-cooled to accelerate the cooling of the casting. By using this method and claim 3 together, during the pouring operation, the cooling metal effect is suppressed to such an extent that the hot water flow is not hindered, and after the pouring operation is completed, the cooling metal effect is maximized. I can do things.

(Invention of Claim 4)
The explanation up to the previous page was based on the premise that a “push-up” is installed in the casting, but the invention of claim 4 provides a technique capable of minimizing this push-up. For this purpose, a donut-shaped closed space is formed by the casting platen 10, the hollow ring, and the casting frame 50 that covers the mold, and after pouring is completed, the molten metal is pressurized from the open surface side of the pouring gate, so The molten metal of the 19 part is utilized as a hot water.

  Specifically, as shown in FIG. 14, the mold is surrounded by a closed mold 50, the molten metal is filled into the mold and mold using the techniques of claims 1 to 3, and then the chute opening surface is pressurized. By covering with the lid 51 and pressurizing the gas, the molten metal in the gate 18 and the molten metal in the runway 19 can be used as the hot water. In addition, when pressurizing from the chute part and the sprue part to exert the hot water effect, the absolute amount of the molten metal in the spout part is insufficient (insufficient as the amount of the molten metal), or the molten metal in the cross-sectional area reducing part by the gypsum cell is first There is a case where a problem arises that the hot water supply is not sufficiently supplied until the end. In this case, the pressure port 52 may be newly set on the opposite side of the gate as follows.

  As the pressurizing method, there are various methods such as gas pressurization shown in FIG. 15, piston pressurization shown in FIG. 16, pressurization by the head pressure using the height difference of the molten metal shown in FIG. Can be used. Further, a combination of gas pressurization and head pressure may be used. This method has an advantage that it is easy to take a method of applying external heat only to the pressure sleeve portion to delay the solidification of the molten metal in the pressure sleeve.

  FIG. 18 shows a perspective view of the casting surface plate 10 and the detachable surface plate 31 when the pressure port 52 is newly set as described above, and FIG. 19 shows a sectional view of the casting method. As shown in these drawings, a pressure port groove 53 may be formed on the opposite side of the pouring groove 12 of the casting surface plate 10 and a pressure sleeve 54 may be erected thereon. A pressure port 52 is also formed in the hollow ring 16.

  The theoretical value of the amount of hot water required to compensate for the solidification shrinkage in a normal casting is about 10% of the amount of hot water in the product part, whereas in the actual casting plans of gravity casting, overturning casting, and suction casting, 20-50 % Hot water is often set. This is because 100% of the hot water cannot be used to replenish the melt solidification shrinkage of the product part, and it is desired to utilize the head pressure effect due to the height of the hot water. (There is also a meaning to secure the heat capacity so that the molten metal in the hot metal part does not solidify until the end.) On the other hand, if low pressure casting and die casting are set up well, the theoretically minimum level of hot water is required. I can finish it. (However, in the case of low-pressure casting, the molten metal must remain in the pressurizing furnace until the end. This molten metal can be reused, but this part must also be considered as “discarded hot water”. Therefore, the low-pressure casting method is not necessarily a casting method with good alloy efficiency. From this, the method of claim 4 is basically a gravity casting method, but it can aim for an alloy efficiency superior to that of the low-pressure casting method. Is.

Examples of each invention are shown below.
FIG. 20 shows the shape of a ring casting for a tire mold manufactured through all the examples. The shape of the tire design surface is formed on the inner peripheral surface of φ1100. The materials used and casting conditions are as follows.
☆ Gypsum mold, gypsum cell material
Noritake Gypsum G-6 non-foamed gypsum, 1 g of gypsum, formulated with 500 g of water.
☆ Alloy material used
JIS aluminum alloy AC4C (7% Si, 0.4% Mg, 0.4% Fe remaining Al)
☆ Casting conditions
Cast frame, casting surface plate material: FC250 (gray cast iron)
Desorption platen material: S45C (carbon steel)
Casting frame preheating temperature: 150 ~ 200 ℃
Casting surface plate, desorption surface plate temperature: 25 ℃ (room temperature)
Alloy casting start temperature: 660 ℃
☆ Insulating material used Nippon Steel Chemical Co., Ltd. SC paper 1260I 3mm thick product

<Example 1> Examples of Claims 1, 2, and 3 The casting shown in FIG. 20 was cast by the casting method shown in FIGS. 12 and 13 (the height of the feeder is 300 mm). However, a punching plate-like heat insulating material with a hole diameter of 20% is attached to the entire surface of the casting surface plate, the desorption surface plate, and the molten metal contact surface on the bottom of the casting frame directly above the gypsum mold. The casting was carried out. The casting thus obtained was sound with no casting defects, and the entire shape (design) required for the tire mold was faithfully cast.

<Example 2> Example of Claim 4 A casting as described above was cast by the casting method shown in FIG. The inner diameter of the pressure sleeve is 250 mm, and the upper end of the pressure sleeve is about 700 mm higher than the height of the casting product. After the pouring of the product is completed, the molten metal is additionally replenished in the pressure sleeve and the pressure port is covered. Later, it was pressurized with 0.12 MPa of factory air to complete the melt solidification. (The conditions for applying the heat insulating material to the bottom surface of the casting frame immediately above the casting surface plate, the desorption surface plate, and the gypsum mold were the same as in Example 1.) The casting thus obtained was healthy without casting defects, The entire shape (design) required for the tire mold was faithfully cast. Compared with Example 1, the casting weight could be reduced by about 150 kg.

FIG. 1 is a schematic cross-sectional view illustrating the gravity casting method. It is typical sectional drawing explaining the falling casting method. It is typical sectional drawing explaining the suction casting method. It is typical sectional drawing explaining a low pressure casting method. It is typical sectional drawing explaining the die-casting method. It is process explanatory drawing explaining the well-known technique in the case of manufacturing the ring casting for tire molds with a gravity casting method. It is process explanatory drawing explaining the well-known technique in the case of manufacturing the ring casting for tire molds by a low pressure casting method. It is a disassembled perspective view which shows embodiment of invention of Claim 1. FIG. It is sectional drawing which shows embodiment of invention of Claim 1. It is sectional drawing which shows embodiment of invention of Claim 2. It is sectional drawing explaining the cooling metal installation to the casting in invention of Claim 2. It is a perspective view explaining the cooling metal in invention of Claim 3. It is a perspective view explaining the cooling metal in invention of Claim 3. It is sectional drawing which shows embodiment of invention of Claim 4. It is sectional drawing which shows a gas pressurization system. It is sectional drawing which shows a piston pressurization system. It is sectional drawing which shows the pressurization system by a head pressure. It is a perspective view of the casting surface plate and the removal | desorption surface plate in invention of Claim 4. It is sectional drawing of the casting method in invention of Claim 4. It is a perspective view of the ring casting for tire molds manufactured in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface plate 2 Gypsum mold 3 Casting frame 4 Casting frame 5 Cooling metal 6 Gypsum surface plate 7 Runway board 8 Pressurizing furnace 10 Casting surface plate 11 Ring-shaped groove 12 Groove for pouring gate 13 Groove for weir 14 Heat insulating material 15 Ring Shaped heat insulating material 16 hollow ring 17 hollow ring 18 sprue 19 runner 20 weir structure 21 cast frame 22 gypsum cell 30 circular counterbored groove 31 demounting surface plate 40 heat insulating material 50 cast frame 52 pressure lid 52 pressure port

Claims (4)

  When manufacturing ring castings for tire molds by the gravity casting method, on the casting surface plate made of a material that does not melt or collapse with the molten alloy to be cast, it is slightly larger than the outer diameter of the ring casting with an open top structure A ring-shaped groove shape with an inner diameter is engraved, and a hollow ring with a shape that can be capped on it is assembled on the top and bottom, and a heat insulator is attached to the inner surface of the groove shape. A casting method for a tire mold, wherein a runner, runner, and dam structure can be used repeatedly by forming a runner and a dam structure.   In the tire mold casting method according to claim 1, a circular counterbore groove is formed in the center portion of the casting surface plate, and a detachable surface plate in a form that can be detached is separately manufactured. By mounting a ring mold on the panel, the mold assembly and re-drying work can be performed independently and the insulation work can be applied to the gate, runner and weir structure of the casting surface plate independently. The tire mold casting method.   3. The method for casting a tire mold according to claim 1 or 2, wherein a desorption surface plate and a casting surface plate are used as the lower cooling metal of the mold, and a casting frame installed immediately above the mold is used as the upper cooling metal. Then, heat insulating material is pasted on these molten metal contact surfaces, and by disposing a plurality of discontinuous openings in this heat insulating material, the cooling efficiency is adjusted by adjusting the opening ratio, and the upper and lower sides are substantially adjusted. A method for casting a tire mold characterized by having an equivalent cooling metal effect and at the same time ensuring hot water flow during pouring.   The casting method of the tire mold according to any one of claims 1 to 3, wherein a donut-shaped closed space is formed by a casting surface plate, a hollow ring, and a casting frame covering the mold, and after pouring is completed, an open surface of the gate is formed. A method for casting a tire mold, wherein the molten metal is pressurized from the side to utilize the molten metal at the gate and runner as the hot water.

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