JP2019098372A - Casting apparatus for tire molding die and casting method for tire molding die - Google Patents

Abstract

To provide a casting apparatus and a casting method for a die for molding a tire, by which bubble defects are suppressed and the casting time is decreased to improve the casting quality.SOLUTION: In the casting apparatus, one or a plurality of radial grooves (3) extending in the radial direction from the center axis (Lc) are formed on the upper surface of a base plate (2). A groove pouring port (7i) is provided at the distal end part (3a) of the radial grooves (3) to be connected to a pouring jig (60) outside an outer cylinder frame (40) and to enter the molten metal into the radial groove (3). A groove outlet (7e) for tapping molten metal into a casting space (50) from the radial grooves (3) is provided at a central groove end part (3b) of the radial grooves (3). A feeder space (35) for storing a feeder is formed immediately above the groove outlet (7e) by a feeder frame (30) arranged on the casting space (50).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a casting apparatus and a casting method for casting a tire molding die by a gravity casting method.

When casting a molten metal in a casting space formed in a mold when casting a mold for tire molding, when air bubbles are caught in the molten metal and enter the casting space, the cells stick to the surface of the gypsum mold Cause bubble defects in the cast product.
Among casting defects, bubble defects are the most likely defects.

As a casting method effective as a countermeasure against the bubble defect, there is a low pressure casting method (see, for example, Patent Document 1).
In the low-pressure casting method disclosed in Patent Document 1, the molten metal stored in the sealed holding furnace is pressurized in the holding furnace by blowing in compressed gas so that the molten metal is lifted through the stalk and poured into the casting space. It is a method of pouring water, and it is extremely rare that bubbles are caught in the molten metal during pouring.
However, this low pressure casting method requires a complicated and large dedicated low pressure casting apparatus, requires a large capital investment, has a high manufacturing cost, and makes it difficult to cast a large tire mold.

There is also a gravity casting method as a casting method.
The gravity casting method is a casting method in which molten metal is poured using gravity from a high position in a casting space formed in a mold, and a large-scale device is not required, and equipment investment and manufacturing cost can be kept low. It is also possible to cast tire molds.

However, in the gravity casting method, bubbles are more easily caught in the molten metal at the time of pouring than in the low pressure casting method, and the occurrence of casting defects due to the bubbles is more likely to occur.
Therefore, there is an example of a gravity casting method (see, for example, Patent Document 2) in which generation of air bubble defects is suppressed by preventing air bubbles from entering the casting space as much as possible.

Japanese Patent Application Laid-Open No. 57-58968 JP 2007-144480 A

In the tire molding mold casting apparatus disclosed in Patent Document 2, a plaster mold and a hollow ring (corresponding to an outer cylinder flask) surrounding the outer periphery of the plaster mold are installed on a surface plate, and the plaster mold and the hollow ring An annular casting space is formed between them.
A ring-shaped groove is engraved on the upper surface of the platen, and the ring-shaped groove is covered from above by a hollow ring to form a ring-shaped runner.

The ring-shaped groove has a centrifugal-side extending portion in which a portion thereof extends to the outside of the hollow ring in the centrifugal direction, and a pouring gate is connected to the centrifugal-side extending portion, and the ring-shaped The center side extension part extended to the inner side of the hollow ring in the center direction at a plurality of locations of the groove, and the center side extension part is open to the casting space.
Therefore, the molten metal that has been poured into the centrifugal side extension part from the pouring gate flows through the ring-shaped groove and is discharged from the plurality of center side extension parts into the pouring space and is filled into the pouring space.

  The runner from the sprue to the pouring space through the ring-shaped groove forms a ring-shaped groove, so the distance is considerably long, and the molten metal passes through this long-distance runner. , It is suppressed that the bubble which arose by pouring in to casting space.

In order to float and separate the bubbles entrained in the molten metal in the runner, it is necessary to suppress the flow velocity to a certain speed or lower, and the lower limit of the time for filling the molten metal into the casting space inevitably exists.
When the casting time is long, transfer of the shape of the gypsum mold becomes slow, and there is a problem that the pressure of the feeder does not work effectively due to the timing delay, which affects the casting quality not so good in fine processing.

  The present invention has been made in view of such a point, and the object of the present invention is to provide a casting apparatus for a tire molding die, in which the occurrence of bubble defects is suppressed and the casting time is shortened to improve the casting quality The point is to provide a casting method.

In order to achieve the above object, a casting apparatus for a tire mold according to the present invention is:
An annular plaster mold installed on the surface plate,
An outer cylinder flask which is installed on the surface plate and surrounding the outer periphery of the plaster mold coaxially with the center axis to form an annular casting space between the plaster mold and the plaster mold;
A pouring jig which is provided on the surface plate outside the outer cylinder flask and pours the molten metal by gravity in order to cast the molten metal in the casting space;
In a tire molding die casting apparatus provided with
The upper surface of the platen has one or more radial grooves extending radially about the central axis,
The centrifugal groove end portion of the radial groove is provided with a groove port located outside the outer cylinder flask and connected to the pouring jig to insert the molten metal into the radial groove.
The center-side groove end of the radial groove is provided with a groove outlet located inside the outer cylindrical flask and for discharging the molten metal from the radial groove to the casting space,
It has a feeder frame which is disposed on the casting space and in which a feeder space (35) for storing the feeder is formed immediately above the groove outlet port.

  According to this configuration, it is a gravity casting type casting apparatus in which molten metal is poured by gravity using a pouring jig in order to cast molten metal in a casting space, and a large-scale apparatus is unnecessary, and equipment investment and manufacturing cost are low. In addition to being suppressed, it is also possible to cast molding dies for large tires.

  In addition, since a pouring space is formed immediately above the gutter outlet by the pouring frame disposed above the pouring space, air bubbles generated in the molten metal at the time of pouring are discharged from the gutter into the gutter Further, air bubbles that move into the radial groove and enter the casting space from the groove spout are mostly discharged to the outside through the feeder in the pouring space immediately above the groove spout, and are thus filled in the casting space It is possible to minimize the formation of bubbles in the molten metal and to suppress the occurrence of bubble defects in the cast product.

In the above configuration,
The pouring jig is configured such that a chute portion extends downward from a pool at the upper end,
The lower end of the chute portion is connected to the end of the centrifugal groove of the radial groove in the surface plate, and the inside of the chute portion is communicated with the radial groove via the groove port.
The groove entrance may be closed openably / closably by a plug member.

  According to this configuration, when the groove entry port is closed by the plug member, when the groove entry port is opened by the plug member, the molten metal stored in the inside of the chute portion and the pool portion at the upper end of the chute portion As the molten metal at the bottom of the chute portion is drawn into the gutter inlet, it enters the radial groove and is cast into the casting space through the radial groove, so the molten metal is poured into the chute portion compared to pouring air into the chute portion The occurrence of air bubble defects can be further suppressed.

By minimizing the air bubble entrainment at the time of pouring, it becomes unnecessary to control the casting speed, and it becomes possible to shorten the casting time.
The radial groove on the upper surface of the platen is a runner communicating the groove entrance connected with the pouring jig outside the outer cylinder flask and the groove outlet for pouring the molten metal into the casting space inside the outer cylinder flask. is there.
That is, since the radial groove is a runner which penetrates the outer cylinder flask from the outside to the inside at the shortest distance, the distance is extremely short.

As described above, by shortening the radial groove (runner), the casting time in which the molten metal is cast in the casting space is shortened.
As a result, the shape of the mold can be transferred quickly, and the casting quality can be improved at various points, such as the pressure of the feeder acting effectively early.

In the above configuration,
The gypsum mold is configured by combining a product mold and a dummy mold in the circumferential direction,
The dummy mold may be disposed in the vicinity of the groove outlet.

  Since air bubbles infiltrate into the casting space from the groove outlet, air bubbles are particularly easily mixed with the molten metal in the casting space in the vicinity of the groove outlet, but according to the above configuration, the dummy mold is disposed in the vicinity of the groove outlet. Therefore, the molten metal corresponding to the dummy mold is particularly likely to be mixed with air bubbles, and the dummy cast portion corresponding to this dummy mold is separated from the product cast portion as a dummy and removed, so even if the air is mixed into the dummy cast portion. It is difficult for air bubbles to be mixed in the product casting part, and the occurrence of air bubble defects in the product casting part can be minimized.

In the above configuration,
The groove outlet may be covered with a casting filter disposed in the casting space so as to face the outer peripheral surface of the lower end portion of the dummy mold.

  According to this configuration, the casting filter disposed in the pouring space facing the outer peripheral surface of the lower end portion of the dummy mold covers the slot spout, so the molten metal spouting from the slot spout to the pouring space is cast By the filter, bubbles as well as foreign substances are removed, and bubbles are less likely to be mixed in the product casting part, generation of bubble defects can be further suppressed, and foreign substances are also removed, and the quality of product casting can be improved.

  Since the casting filter faces the outer peripheral surface of the lower end of the dummy mold, the casting filter is positioned below the dummy casting portion corresponding to the dummy mold, and the dummy casting portion The cast filter can also be removed at the same time as the dummy is separated and removed from the product casting.

In the above configuration,
The radiation groove may be provided with a weir for restricting the movement of the air bubble.

  According to this configuration, the radial groove is provided with a weir that restricts the movement of the air bubble, so the bubble in the molten metal flowing to the groove outlet in the radial groove is blocked by the weir, and from the groove outlet to the casting space Air bubbles can be prevented as much as possible, and the generation of air bubble defects can be further suppressed.

The method for casting a tire mold according to the present invention is
In the tire molding mold casting method, the tire molding mold is cast using the tire molding mold casting apparatus.
Molten metal is poured from the gutter into the radial groove by the grouting jig, poured from the gutter into the casting space and filled in the casting space, and then a feeder is made to overflow from the casting space, and then The molten metal is cooled and solidified.

According to this configuration, it is possible to eliminate the restriction on the casting speed and to shorten the casting time, so that the shape of the mold is transferred quickly, and the pressure of the feeder acts effectively earlier, etc. Casting quality can be improved at various points.

The molten metal is poured from the gutter into the radial groove by the pouring jig, poured from the gutter into the casting space and filled into the casting space, so the outer cylinder form is penetrated from the outside through the short radial groove The molten metal is filled in the casting space,

  In addition, most of the air bubbles that move into the radial groove and enter the casting space from the groove outlet rise and are dissipated to the feeder directly above the groove outlet, so the air bubbles remain in the molten metal filled in the casting space And the occurrence of bubble defects can be suppressed.

  The present invention is a gravity casting type casting apparatus in which molten metal is poured by gravity using a pouring jig in order to cast molten metal in a casting space, and a large-scale apparatus is not required, and equipment investment and manufacturing cost can be suppressed low. At the same time, it is also possible to cast molding dies for large tires.

Further, since the casting speed can be set large, the casting time in which the molten metal is filled in the casting space can be shortened.
Therefore, the shape of the mold can be transferred quickly, and the casting quality can be improved in various points, such as the pressure of the feeder acting effectively early.

  Since a pouring space is formed immediately above the gutter outlet by the pouring frame disposed above the pouring space, air bubbles generated in the molten metal at the time of pouring enter into the radial gutter from the gutter entry Further, the bubbles moving into the radial groove and entering the casting space from the groove spout are mostly dissipated as they rise to the feeder in the feed space immediately above the groove spout and are dissipated, so the molten metal filled in the casting space Air bubbles are less likely to be left behind, and the occurrence of air bubble defects in the cast product can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is whole perspective view of the casting apparatus in front of casting of the mold for tire molding which concerns on one embodiment of this invention. It is a vertical sectional view of the casting apparatus of the II-II arrow of FIG. It is a perspective view of a surface plate. It is an exploded perspective view of a platen and heat insulation paper. It is an exploded perspective view of a platen and heat insulation paper. It is an exploded perspective view of a platen, a mold arrangement table, a pressing ring and a gate member. It is a perspective view of the combination which combined a platen, a casting_mold | template arrangement table, a pressing ring, and a gate member. It is a perspective view of the combination which combined the gypsum mold with the combination shown in FIG. It is a perspective view of the combination which combined the feeder with the combination shown in FIG. It is a perspective view of the combination which combined the outer cylinder flask with the combination shown in FIG. It is a perspective view of the combination which combined the plug member and opening-closing rod with the combination shown in FIG. It is a perspective view of the combination which combined the chute | shoot part and the pool part with the combination shown in FIG. It is a vertical cross-sectional view of the casting apparatus after casting. It is explanatory drawing which shows the process in which the metal mold | die for tire molding is manufactured from the casting cast by the casting apparatus. It is a perspective view of the assembly of 1 process of the assembly in the casting apparatus which concerns on another embodiment. It is a vertical cross-sectional view of the casting apparatus after casting.

Hereinafter, an embodiment according to the present invention will be described based on FIGS. 1 to 14.
FIG. 1 is an overall perspective view of a casting apparatus 1 for a tire molding die according to an embodiment of the present invention, and FIG. 2 is a vertical view of the casting apparatus 1 of FIG. FIG.

The main casting apparatus 1 for a tire molding die is a gravity casting type casting apparatus for pouring molten metal by gravity using a pouring jig in order to cast molten metal in a casting space.
Therefore, the present casting apparatus 1 does not require a large-scale apparatus like a low-pressure casting type casting apparatus, can reduce equipment investment and manufacturing cost low, and can also cast a molding die for a large-sized tire.

Further, the present casting apparatus 1 is an apparatus which casts a dummy mold between product molds and casts by using an annular cast gypsum.
That is, since the cast product cast part and the dummy cast part are alternately formed in the circumferential direction in the cast ring casting, as will be described later, a plurality of rings of product casts (product segments) obtained by dividing and excluding the dummy cast are formed. The parts are combined to produce one tire mold.
The main casting apparatus 1 is a casting apparatus for manufacturing one tire molding mold by casting products of two rings.

  With reference to the overall perspective view of the permanent casting apparatus 1 of FIG. 1 and the cross-sectional view of the permanent casting apparatus 1 of FIG. 2, the structure of the permanent casting apparatus 1 will be described below in accordance with FIGS. Do.

The surface plate 2 is shown in FIG.
The surface plate 2 is a cast iron flat plate, and as shown in FIG. 3, five places equidistantly spaced from each other on the outer periphery of the hollow disk project radially in the center axis Lc of the central annular portion 2a. , Has a five-pointed star shape in plan view.
In the surface plate 2, the upper surface of the central annular portion 2 a is recessed from the outer peripheral annular portion 2 b on the outer periphery thereof.
The outer circumferential annular portion 2b has a five-pointed star shape, and has projecting portions 2bb projecting in the radial direction at five positions on the outer peripheral edge of the outer circumferential annular portion 2b.

On the upper surface of the outer peripheral annular portion 2b of the platen 2, the radial grooves 3 are formed in a radial direction centering on the central axis Lc, from the vicinity of the inner peripheral edge of the outer peripheral annular portion 2b toward each projecting portion 2bb .
The centrifugal groove end 3a of the radial groove 3 is expanded in a cylindrical shape at the protrusion 2bb.
The central groove end 3b of the radial groove 3 is close to the inner peripheral edge of the outer circumferential annular portion 2b.

In the casting apparatus 1 in the present embodiment, two of the five radial grooves 3 of the surface plate 2 are used as runners, and the other three radial grooves 3 are filled with the filling 4. (See Figure 4).
Referring to FIGS. 4 and 5, heat insulating papers 5a and 5b are lined on the bottom and side wall surfaces of the radial groove 3 used as a runner.
Between the opposing side walls of the frame-shaped heat-insulating paper 5b lined with the side wall surface of the radial groove 3, two bar-shaped wedge members 6 are installed from above.

Then, referring to FIGS. 5 and 6, the heat insulating paper 7 covers the top of the radial groove 3 lined with the heat insulating papers 5a and 5b and on which the wedge member 6 is installed.
At the centrifugal side end of the heat insulating paper 7 covering the centrifugal side groove end 3a of the radial groove 3, a grooved spout 7i which is a circular hole is formed.
The center side end of the heat insulating paper 7 opens a part of the center side groove end 3b of the radial groove 3 as a groove outlet 7e and covers the other (see FIG. 6).
The heat insulating papers 5a, 5b, 7 are heat insulating materials which are made of ceramic fiber in the form of paper and are excellent in heat resistance.

Next, referring to FIGS. 6 and 7, mold array table 8 which is a hollow disc-like cast iron article is fitted into central annular portion 2a of surface plate 2.
In the platen 2, when the mold array table 8 is fitted into the central annular portion 2a, the upper surface of the mold array table 8 is flush with the upper surface of the outer peripheral annular portion 2b of the platen 2.

Then, the pressing ring 9 is placed on the outer circumferential annular portion 2 b of the surface plate 2.
The pressing ring 9 is a carbon steel plate and has an outer peripheral annular portion 9 b on the outer periphery of the central annular portion 9 a like the surface plate 2, and the outer peripheral annular portion 9 b has the same shape as the outer peripheral annular portion 2 b of the surface plate 2. It forms an outer peripheral edge, and has projecting portions 9bb projecting radially in five places on the outer peripheral edge to form a five-pointed star shape.

A circular hole 9h is formed in a portion corresponding to the centrifugal groove end 3a of the radial groove 3 formed in the outer peripheral annular portion 2b of the surface plate 2 in the projecting portion 9bb of the outer peripheral annular portion 9b of the pressing ring 9.
The gate member 10 is fitted in the circular hole 9 h of the pressing ring 9 respectively corresponding to the centrifugal groove end 3 a of the two radial grooves 3 used as a runner.
The gate member 10 is made of non-foam plaster, and the inside of the cylinder is hollowed out in a mortar shape to form a conical surface 10c which is tapered downward, and a circular hole 10h is formed at the tip (lower end) of the conical surface 10c. Through.

The upper surface of the center ring 9a of the presser ring 9 is recessed from the outer peripheral annular portion 9b on the outer periphery thereof.
The inner diameter of the central annular portion 9 a of the presser ring 9 is larger than the inner diameter of the outer peripheral annular portion 2 b of the surface plate 2.

When the mold array table 8 is fitted into the central annular portion 2a of the platen 2 and the pressing ring 9 is superimposed on the outer peripheral annular portion 2b, as shown in FIG. 7, the central annular portion 9a of the pressing ring 9 The groove outlet 7e which is not covered with the heat insulating paper 7 of the center side groove end 3b of the radial groove 3 of the surface plate 2 is opened inside.
When the gate member 10 is inserted into the circular hole 9 h of the holding ring 9, the circular hole 10 h at the lower end of the conical surface 10 c of the gate member 10 is a centrifugal of the heat insulating paper 7 covering the upper side of the radiation groove 3 of the platen 2. It corresponds with the groove entrance 7i at the side end (see FIG. 2).

  Referring to FIG. 2, the radial groove 3 whose inner surface is lined by the heat insulating papers 5a, 5b and 7 of the surface plate 2 has the molten metal from the groove entrance 7i corresponding to the circular hole 10h of the gate member 10 The molten metal 3a is poured into 3a and flowed toward the center side groove end 3b to form a molten metal runner for pouring out of the groove outlet 7e of the center side groove end 3b.

Next, as shown in FIG. 8, on the mold arrangement table 8 fitted in the center of the platen 2, a plaster mold 20 which is lined with a backing material 25 and has an annular structure is disposed.
The gypsum mold 20 is configured by alternately combining five product molds 21 and five dummy molds 22 in the circumferential direction.

The five product molds 21 have the same shape and are circumferentially equally spaced in the gypsum mold 20.
The five dummy molds 22 also have the same shape and are equally spaced circumferentially in the gypsum mold 20.
The outer diameter of the dummy mold 22 is smaller than the outer diameter of the product mold 21.

The gypsum mold 20 is disposed on the mold array table 8 in a posture in which the five dummy molds 22 respectively face the protrusion 2 bb having the five radial grooves 3 of the platen 2, and the central circle of the presser ring 9. The ring portion 9a is penetrated upward and protruded.
Dummy molds 22 respectively corresponding to the two radial grooves 3 used as runners are disposed in the vicinity of the groove outlet 7e of the center side groove end 3b of the radial groove 3 (see FIG. 2).

The product mold 21 is made of non-foamed gypsum, and a pattern design is given to the outer peripheral mold surface.
The dummy mold 22 fitted between the product molds 21 and 21 is made of non-foamed gypsum with a higher density than the product mold 21 and has a large resistance to casting shrinkage.

Next, as shown in FIG. 9, a feeder frame 30 configured annularly is stacked on the gypsum mold 20.
The feeder frame 30 is configured by connecting a plurality of connection walls 33 that direct the inner cylinder wall 31 and the outer cylinder wall 32 in the radial direction.
Therefore, ten fan-shaped spaces partitioned by the connecting wall 33 are formed between the inner cylinder wall 31 and the outer cylinder wall 32, and the feed space 35 and the bottom of the fan-shaped space in which the fan-shaped space penetrates up and down are formed among them. The dummy spaces 36 closed by the bottom wall 34 (see FIG. 2) are alternately formed circumferentially five by five.

Referring to FIG. 2, in the feeder frame 30, the outer diameter of the outer cylindrical wall 32 is larger than the outer diameter of the five product molds 21 configured annularly, and the inner diameter of the central annular portion 9 a of the pressing ring 9 is Approximately equal.
The outer diameter of the inner cylindrical wall 31 of the feeder frame 30 is substantially equal to the outer diameters of the five dummy molds 22 configured annularly, the hollow bottom wall 34 is in contact with the upper surface of the gypsum mold 20, and the feeder frame 30 is Be supported.

When placing the pouring bath frame 30 on the plaster mold 20, the pouring bath frame 30 is placed so that the pouring bath space 35 of the pouring bath frame 30 corresponds to the dummy mold 22 of the plaster mold 20 at the top and bottom. Arrange.
That is, there is a positional relationship in which the feeder space 35 of the feeder frame 30 is located above the outer space of the dummy mold 22.
Insulating paper 38 is lined on the inner wall of the pouring space 35 of the pouring frame 30.

Next, as shown in FIG. 10, the outer cylinder flask 40 is disposed so as to surround the outer periphery of the gypsum mold 20 and the feeder frame 30.
The outer cylinder frame 40 is a cast iron product having a cylindrical shape, and the inner diameter of the outer cylinder frame 40 is equal to the outer diameter of the feeder frame 30 and the inner diameter of the central annular portion 9a of the press ring 9 (see FIG. 2) ).
The outer cylinder frame 40 has flanges 40U and 40L at upper and lower end portions, and the outer diameters of the flanges 40U and 40L are equal to each other and equal to the inner diameter of the outer circumferential annular portion 9b of the press ring 9.

Therefore, referring to FIG. 2, outer cylinder frame 40 has feeder frame 30 inserted inside to surround the outer periphery of gypsum mold 20, and flange 40 L at the lower end is in outer ring portion 9 b of pressing ring 9. It fits and is arrange | positioned on the center annular ring part 9a.
The outer cylinder flask 40 extends above the feeder frame 30.
A heat insulating paper 45 is lined on the inner peripheral surface of the outer cylindrical flask 40 facing the gypsum mold 20.

As shown in FIG. 2, the annular space between the gypsum mold 20 and the outer cylinder flask 40 is a casting space 50.
The upper part of the space facing the mold for product 21 of the casting space 50 is partitioned by the bottom wall 34 of the feeder frame 30, but the space facing the dummy mold 22 of the casting space 50 is above the feeder frame 30 The hot water supply space 35 is communicated with the upper and lower sides.

  Then, since the groove outlet 7e of the center side groove end 3b of the radial groove 3 is opened in the vicinity of the dummy mold 22, the pouring space 35 is positioned immediately above the groove outlet 7e to form a pouring hole ( 2 and 13).

In the radial groove 3 used as a runner, the molten metal enters from the groove entry 7i on the outside of the outer cylinder flask 40, passes under the outer cylinder flask 40, and the groove outlet on the inside of the outer cylinder flask 40 It is a runner which pours from 7e to the casting space 50, and the distance as a runner is short.
The groove outlet 7e of the center side groove end 3b of the radial groove 3 is opened to the casting space 50 in the vicinity of the dummy mold 22, so that the molten metal ejected from the groove outlet 7e faces the dummy mold 22 in the casting space 50. Enter the space to

Next, a pouring jig 60 is provided on each of the gate members 10 located above the centrifugal groove ends 3a of the two radial grooves 3 used as runners.
As shown in FIG. 11, a plug member 61 which contacts the conical surface 10c of the gate member 10 from above to close the circular hole 10h and the groove entry port 7i is provided with the open / close rod 62 extending upward.
The plug member 61 is a member having a shape in which the lower end portion of a cylinder protrudes in a conical shape, and is a high carbon steel coated with a ceramic coating on the surface.

  An open / close rod 62 is connected to the plug member 61, and by pulling up the open / close rod 62 with the plug member 61 upward, the plug member 61 which contacts the conical surface 10c of the gate member 10 and closes the groove entry port 7i And the ditch mouth 7i can be opened.

Next, as shown in FIG. 12, a cylindrical chute portion 65 is liquid-tightly connected and erected on the gate member 10, and a basin 66 formed in a bowl shape at the upper end of the chute portion 65. Is attached.
Thus, the main casting device 1 of the tire molding die is assembled.
Insulating paper 67a, 67b is lined on the inner circumferential surface of the chute portion 65 and the inner surface of the water reservoir portion 66.

Referring to FIG. 2, since the bottom of the water reservoir 66 is open and in communication with the inside of the chute 65, the plug member 61 contacts the conical surface 10c of the gate member 10 to close the groove port 7i. When it is closed, the open / close rod 62 connected to the plug member 61 extends upward in the chute portion 65, penetrates the inside of the water reservoir portion 66, and extends upward from the water reservoir portion 66.
When the molten metal is injected into the pool portion 66 in a state where the groove entry port 7i is closed by the plug member 61, the molten metal fills the inside of the chute portion 65 and further, as shown in FIG. Fulfill.

1 and 2, each plug member 61 in the two pouring jigs 60 closes the groove entry port 7 i, and the molten metal (portion to which the spout pattern is formed) is in each chute portion 65 and each pool portion It is the whole perspective view and the perpendicular cross section of this casting device 1 in the state where 66 inside was filled.
The molten metal used in the main casting apparatus 1 is a molten aluminum alloy.

  When the respective opening and closing rods 62 of the two pouring jigs 60 are grasped and pulled up from this state, the plug members 61 are pulled up integrally, and the groove pouring ports 7i are opened in the two pouring jigs 60. The molten metal stored in the water reservoir 66 enters the radial groove 3 from the grooved hole 7i by gravity, and the molten metal that penetrates from the outside to the inside of the lower part of the outer cylinder form 40 by the runner of the radial groove 3 is The hot water is poured from the groove outlet 7e into the pouring space 50, and the pouring space 50 is filled, and the pouring space 35 is filled to form a pouring bath.

FIG. 13 is a vertical cross-sectional view of the casting apparatus 1 showing a state where casting of the molten metal is finished.
The radial groove 3 on the upper surface of the platen 2 has a groove port 7i connected to the pouring jig 60 outside the outer cylinder flask 40 and a groove outlet for pouring molten metal into the casting space 50 inside the outer cylinder flask 40. It is a runner communicating with 7e.
Since the bubble entrainment at the time of pouring can be extremely reduced, the casting speed can be increased, and the casting time in which the molten metal is cast in the casting space 50 can be shortened.

In the present casting apparatus 1, since two pouring jigs 60 are further used, molten metal is simultaneously cast from the two pouring jigs 60 into the casting space 50, and the casting time is becoming shorter and shorter.
As the casting time is short, the shape of the mold is transferred quickly, and the casting quality can be improved in various points, such as the pressure of the feeder acting effectively early.

  Since the pouring space 35 of the pouring frame 30 is positioned immediately above the groove outlet 7e of the center side groove end 3b of the radial groove 3 and a pouring bath is formed, bubbles generated in the molten metal at the time of pouring are grooved Most of the air bubbles that enter the radial groove 3 from the inlet 7i and move on the radial groove 3 and enter the pouring space 50 from the radial outlet 7e are discharged to the outside through the feeder directly above the radial outlet 7e. The number of bubbles remaining in the molten metal filled in the casting space can be minimized, and the generation of bubble defects can be suppressed.

  Further, in the final casting apparatus 1, the molten metal stored in the chute portion 65 and in the pooling portion 66 at the upper end of the chute portion 65 is blocked by the groove entry port 7i being closed by the plug member 61 of the pouring jig 60. When the member 61 is pulled upward and the ditch hole 7i is opened, the molten metal at the bottom of the chute portion 65 is drawn into the ditch hole 7i so as to be drawn into the ditch hole 3i, and the casting space is inserted via the ditch 3 Since it is cast into 50, bubbles can be floated and separated in advance in the accumulated molten metal, so generation of bubbles at the time of pouring is less than pouring molten metal into the chute portion 65, and the bubbles are further increased. The occurrence of defects can be suppressed.

  Furthermore, in the present casting apparatus 1, since the weir member 6 for restricting the movement of the air bubble is provided in the radial groove 3, the air bubble in the molten metal flowing in the radial groove 3 to the groove outlet 7e is blocked by the weir member 6. As a result, the entry of air bubbles into the casting space 50 from the groove outlet 7e can be prevented as much as possible, and the occurrence of air bubble defects can be further suppressed.

A cast cast by cooling and solidifying the molten metal thus cast has a shape shown in (1) of FIG. 14 when cast.
The as-cast casting 80 has a shape indicated by the flow state of the molten metal shown in the vertical sectional view of the casting apparatus 1 of FIG.
In the casting 80 shown in (1) of FIG. 14, the casting portion in the chute portion 65 of the pouring jig 60 is removed.

  Therefore, the casting 80 shown in (1) of FIG. 14 is used as a runner with an annular ring casting 81 formed by the casting space 50, a feeder casting portion 85 formed by the feeder space 35, and the like. It comprises a runner casting 86 formed by two radial grooves 3.

The main casting apparatus 1 uses the gypsum mold 20 configured by combining the product mold 21 and the dummy mold 22 in the circumferential direction, so the annular ring casting 81 is transferred to the product mold 21 and the mold surface is transferred. The product castings 82 to be formed and the dummy castings 83 in contact with the dummy casting mold 22 are alternately formed circumferentially five by five.
The five product castings 82 have the same shape and are equally spaced circumferentially in the ring casting 81.

The feeder casting portion 85 is formed to extend upward from the five dummy casting portions 83.
The two runner castings 86 extend in the radial direction from the lower part of the two dummy castings 83, respectively.

  The ring casting 81 shown in (2) of FIG. 14 is obtained by cutting two runner castings 86 from the ring casting 81 of this as-cast casting 80 and cutting five dummy castings 83. It is formed.

In the ring casting 81, five product casting portions 82 and five dummy casting portions 83 are alternately formed in the circumferential direction, and external force is applied to the inner surface of the dummy casting portions 83 from inside to correct the diameter expansion Then, the outer periphery is further processed to form a diameter expanded ring casting 81A whose diameter is expanded as shown in (3) of FIG.
In the enlarged diameter ring casting 81A, five product castings 82a and five dummy castings 83a are alternately formed in the circumferential direction.
The product casting portion 82a is somewhat larger in circumferential direction width than the dummy casting portion 83a.

Next, the enlarged diameter ring casting 81A is cut at equal intervals in the circumferential direction using a wire electric discharge machine or the like and divided into ten sectors.
As shown in FIG. 14 (4), the product casting portion 82a of the enlarged diameter ring casting 81A is cut out as a sector of the product segment 92a except for the central portion except for both circumferential ends.
Dummy segments including dummy castings 83a which are the remaining sectors are removed.
The diameter expansion correction may be performed after dividing into sectors.

As five product segments 92a are cut out from one diameter-expanding ring casting 81A, five product segments 92b are cut out from another diameter-expanding ring casting similarly formed, as shown in (5) of FIG. Then, the five product segments 92a and the five product segments 92b are annularly combined to assemble one tire molding die 90 shown in (6) of FIG.
Thus, the tire molding die 90 is manufactured.

  As described above, in the ring casting 81 serving as the base of the tire molding die 90 to be manufactured, five product casting portions 82 and five dummy casting portions 83 are alternately formed in the circumferential direction, and among them, the dummy The casting portion 83 is formed in a space facing the dummy mold 22 of the casting space 50 of the casting apparatus 1, and as shown in FIG. 13, the dummy mold 22 is disposed in the vicinity of the groove outlet 7 e of the radial groove 3. In particular, air bubbles are easily mixed in the dummy casting portion 83 in contact with the dummy mold 22.

  However, since the dummy casting portion 83 corresponding to the dummy mold 22 is separated (sector division) with another product casting portion 82 as a dummy and removed, even if air bubbles are mixed in the dummy casting portion 83, the product casting portion 82 is It is difficult to mix air bubbles, and the occurrence of air bubble defects in the product casting portion 82 can be minimized.

  The upper part of the dummy casting 83 is a feeder casting 85, and many of the air bubbles mixed with the molten metal of the dummy casting 83 are often discharged upward to the molten metal of the feeder casting 85, There are not so many bubbles remaining and mixed in the molten metal of the dummy casting part 83.

Next, a casting apparatus 100 according to another embodiment will be described based on FIG. 15 and FIG.
The present casting apparatus 100 is obtained by adding a casting filter 110 to the casting apparatus 1.
Therefore, in the present embodiment, reference numerals indicating members are the same as those in the above embodiment.

The casting filter 110 is a ceramic foam filter, and has a function of collecting foreign matter and bubbles such as metal oxides and nonmetal inclusions in the molten metal, and also has a function of rectifying the molten metal.
The casting filter 110 is disposed in the pouring space 50 to cover the groove outlet 7e from above.

As shown in FIG. 15, the casting filter 110 is formed by the outer peripheral surface of the lower end portion of the dummy mold 22 disposed in the vicinity of the groove outlet 7e of the radial groove 3 as a runner and the center annular ring of the pressing ring 9. It is fitted between the inner circumferential surface of the portion 9a and, as shown in FIG. 16, in the casting space 50 and in contact with the upper surface of the platen 2 and the upper surface of the mold array table 8, the groove outlet 7e is upward. It is placed covering from
The casting filter 110 extends in the radial direction, in contact with and in contact with the outer peripheral surface of the lower end portion of the dummy mold 22.

  Since the casting filter 110 disposed in the casting space 50 in contact with the outer peripheral surface of the lower end portion of the dummy mold 22 covers the groove outlet 7e from the upper side, the molten metal coming out from the groove outlet 7e to the casting space 50 is The casting filter 110 removes foreign substances and air bubbles, and the product casting part 82 is less likely to contain air bubbles, and generation of air bubble defects can be further suppressed, and foreign substances are also removed to improve casting quality. .

  Since the casting filter 110 is in contact with the outer peripheral surface of the lower end portion of the dummy mold 22, the casting filter 110 is positioned below the dummy casting portion 83 cast corresponding to the dummy mold 22. When the dummy casting 83 is separated from the product casting 82 as a dummy and removed, the casting filter 110 can also be removed at the same time.

  As mentioned above, although the casting apparatus and casting method which concern on embodiment concerning this invention were demonstrated, the aspect of this invention is not limited to the said embodiment, It implements in various aspects in the range of the summary of this invention. Including the

For example, although the casting apparatus which concerns on this Embodiment provided two pouring jigs, one may be sufficient and three or more may be sufficient.
The more the pouring jigs, the shorter the casting time in which the molten metal is cast from the pouring jig into the casting space, and the shape of the mold is quickly transferred, so that the pressure of the feeder acts effectively earlier. Casting quality can be further improved.

  In addition, in order to prevent the molten metal from solidifying in the middle of the casting, the heat insulating paper is uniformly lined on the inner surface of the member such as iron material with high thermal conductivity to which the molten metal contacts, but if the casting time is short, Insulating paper can be lined only at the required location to reduce the amount of insulating paper, which can reduce costs.

  In addition, it is required to heat the flask or the like so that the molten metal does not solidify at the time of casting, but if the casting time is short, it may be possible to cast even at room temperature, and the cost can be reduced. .

In the casting apparatus 1, 100 according to the above embodiment, the gypsum mold 20 is configured by alternately combining five product molds 21 and five dummy molds 22 in the circumferential direction, but there is no dummy mold and a product mold It may be composed only of
In this case, a tire mold is directly cast in a product mold.
Further, the number of product molds and dummy molds constituting the plaster mold may be plural other than five.

DESCRIPTION OF SYMBOLS 1 ... Casting apparatus, 2 ... Plate, 2a ... Central annular part, 2b ... Outer peripheral annular part, 2bb ... Projection part, 3 ... Radiation groove, 3a ... Centrifugal side groove end, 3b ... Central side groove end, 4 ... Stuffing , 5a, 5b: thermal insulation paper, 6: thermal insulation member, 7: thermal insulation paper, 8: mold array table, 9: pressing ring, 9a: central annular portion, 9b: outer peripheral annular portion, 9bb: projecting portion, 9h: circle Hole, 10: gate member,
20 ... gypsum mold, 21 ... product mold, 22 ... dummy mold,
DESCRIPTION OF SYMBOLS 30 ... Pouring frame, 31 ... Inner cylinder wall, 32 ... Outer cylinder wall, 33 ... Connection wall, 34 ... Bottom wall, 35 ... Pouring space, 36 ... Dummy space, 38 ... Insulation paper
40: Outer cylinder frame, 40 U, 40 L: Flange, 45: Insulating paper,
50 ..., casting space,
DESCRIPTION OF SYMBOLS 60 ... pouring jig, 61 ... plug member, 62 ... opening-closing rod, 65 ... chute part, 66 ... hot water storage part, 67a, 67b ... insulation paper,
80: Casting, 81: Ring casting, 82: Product casting part, 83: Dummy casting part, 85: Hot metal casting part,
81A: Expanded ring casting, 82a, 82b: product casting, 83a: dummy casting,
90 ... tire molding die, 92a, 92b ... product segment,
100 ... Casting apparatus, 110 ... Filter for casting.

Claims (6)

An annular plaster mold (20) placed on the platen (2);
An annular casting space (50) is provided on the surface plate (2) and surrounded by the outer periphery of the gypsum mold (20) with the central axis (Lc) coaxial with the gypsum mold (20). An outer cylinder flask (40) to form
A pouring jig (60) provided on the surface plate (2) outside the outer cylinder forming frame (40) and pouring the molten metal by gravity in order to cast the molten metal in the casting space (50); ,
In a tire molding die casting apparatus provided with
The upper surface of the surface plate (2) has one or more radial grooves (3) extending radially about the central axis (Lc),
The centrifugal groove end (3a) of the radial groove (3) is located outside the outer cylinder flask (40) and is connected to the pouring jig (60) to pour the molten metal into the radial groove (3). Equipped with a groove entrance (7i)
A groove spout from which the center groove end (3b) of the radial groove (3) is inside the outer cylindrical flask (40) and which discharges the molten metal from the radial groove (3) to the pouring space (50) Equipped with (7e),
It has a feeder frame (30) which is disposed on the casting space (50) and in which a feeder space (35) for storing the feeder just above the groove outlet (7e) is formed. Casting equipment for tire molds. The pouring jig (60) is configured such that a chute portion (65) extends downward from a well portion (66) at the upper end,
The lower end of the chute portion (65) is connected to the centrifugal groove end portion (3a) of the radial groove (3) in the surface plate (2), and the chute portion (65) is connected via the groove entrance (7i). ) And the radial groove (3) communicate with each other,
The apparatus for casting a tire mold according to claim 1, wherein the groove entry port (7i) is closed openably / closably by a plug member (61). The gypsum mold (20) is configured by combining a product mold (21) and a dummy mold (22) in the circumferential direction,
The apparatus for casting a tire mold according to claim 1 or 2, wherein the dummy mold (22) is disposed in the vicinity of the groove outlet (7e).   The groove outlet (7e) is covered by a casting filter (110) disposed in the casting space (50) so as to face the outer peripheral surface of the lower end portion of the dummy mold (22). The casting apparatus for a tire mold according to claim 3.   The casting apparatus for a tire mold according to any one of claims 1 to 4, wherein the radial groove (3) is provided with a weir (6) for restricting the movement of air bubbles. A casting method for a tire molding die according to any one of claims 1 to 5, wherein the tire molding die is cast using the casting device for a tire molding die according to any one of claims 1 to 5.
The molten metal is poured into the radial groove (3) from the groove entry port (7i) by the pouring jig (60), and poured out from the groove exit port (7e) into the casting space (50) to insert the casting space ( 50) A method of casting a tire molding mold, characterized in that filling is performed, the feeder is made to overflow from the casting space (50), and then the molten metal is cooled and solidified.

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