阅读说明：本技术 轮胎成型用模具的铸造装置和轮胎成型用模具的铸造方法 (Casting device for tire molding die and casting method for tire molding die ) 是由 石原泰之 于 2018-06-15 设计创作，主要内容包括：轮胎成型用模具的铸造装置具有平台(2)和设置在平台(2)之上并在内侧形成浇铸空间(50)的外筒模箱(40),在平台(2)的上表面形成有以中心轴线(Lc)为中心地向放射方向延伸的至少一条放射槽(3)。放射槽(3)的径向外侧槽端部(3a)具备槽流入口(7i),该槽流入口(7i)处于比外筒模箱(40)靠径向外侧的位置并与浇注治具(60)连结,供熔融金属向放射槽(3)内流入,在放射槽(3)的径向内侧槽端部(3b)具备槽流出口(7e),该槽流出口(7e)供熔融金属从放射槽(3)向浇铸空间(50)流出。在浇铸空间(50)之上配设有保温帽(30),利用保温帽(30)在槽流出口(7e)的正上方形成用于积存冒口的冒口空间(35)。根据上述结构,抑制铸造时的气泡缺陷的产生,并且缩短浇铸时间,谋求铸造品质的提高。(A casting device for a tire molding mold comprises a platform (2) and an outer cylinder mold box (40) which is arranged on the platform (2) and forms a casting space (50) inside, at least one radial groove (3) extending in a radial direction with a central axis (L c) as a center is formed on the upper surface of the platform (2), a radial outer groove end (3a) of the radial groove (3) is provided with a groove inlet (7i), the groove inlet (7i) is positioned on a radial outer side of the outer cylinder mold box (40) and connected with a casting jig (60) for allowing molten metal to flow into the radial groove (3), a radial inner groove end (3b) of the radial groove (3) is provided with a groove outlet (7e), the groove outlet (7e) is used for allowing molten metal to flow out from the radial groove (3) to the casting space (50), a heat insulating cap (30) is arranged above the casting space (50), a riser space (35) for accumulation is formed just above the groove (7e) by the heat insulating cap (30), and the casting quality is improved according to the casting structure, thereby suppressing the generation of bubbles.)

1. A casting device of a mold for tire molding, comprising:

a platform (2);

an annular gypsum mold (20) disposed above the platform (2) and having a central axis (L c);

an outer cylinder mold box (40) disposed above the table (2) and annularly surrounding the outer periphery of the gypsum mold (20) coaxially with the center axis (L c), an annular casting space (50) being formed between the outer cylinder mold box (40) and the gypsum mold (20), and

a pouring jig (60) which is provided on the platform (2) outside the outer cylinder mold box (40) and pours the molten metal into the pouring space (50) under the action of gravity,

it is characterized in that the preparation method is characterized in that,

at least one radiation groove (3) extending in a radiation direction around the central axis (L c) is provided on the upper surface of the table (2),

a radially outer groove end portion (3a) of the radiation groove (3) is provided with a groove inlet (7i), the groove inlet (7i) is positioned outside the outer cylinder mold box (40) and connected with the pouring jig (60), and molten metal is supplied to flow into the radiation groove (3),

a radially inner groove end (3b) of the radiation groove (3) is provided with a groove outlet (7e), the groove outlet (7e) is positioned inside the outer cylinder mold box (40), and molten metal flows out from the radiation groove (3) to the casting space (50),

the casting device for the tire molding die is provided with a heat insulating cap (30), wherein the heat insulating cap (30) is arranged above the casting space (50), and a riser space (35) for storing a riser is formed right above the groove flow outlet (7 e).

2. The casting device for a tire molding die according to claim 1,

the pouring jig (60) comprises a sprue cup part (66) at the upper end and a feeding pipe part (65) extending downwards from the sprue cup part (66),

the lower end of the feed pipe part (65) is connected to the radially outer groove end part (3a) of the radiation groove (3) of the table (2), the interior of the feed pipe part (65) and the radiation groove (3) communicate with each other via the groove inlet (7i),

the groove inlet (7i) is closed by a plug member (61) so as to be openable and closable.

3. The casting device for a tire molding die according to claim 1 or 2,

the annular plaster mold (20) is formed by combining a product mold (21) and a dummy mold (22) in the circumferential direction,

the dummy mold (22) is disposed in the vicinity of the groove outlet (7 e).

4. The casting device for a tire molding die according to claim 3,

a casting filter (110) is disposed in the casting space (50) so as to face the outer peripheral surface of the lower end portion of the dummy mold (22), and the groove outlet (7e) is covered with the casting filter (110).

5. The casting device for a tire molding die according to any one of claims 1 to 4,

a weir (6) for restricting the movement of bubbles is provided in the radiation tank (3).

6. A casting method of a tire molding die, which comprises casting the tire molding die using the casting apparatus of the tire molding die according to any one of claims 1 to 5,

the casting jig (60) is used to cause the molten metal to flow into the radiation trough (3) from the trough inlet (7i), and the molten metal flows out from the trough outlet (7e) to the casting space (50) to be filled in the casting space (50), and further cause the riser to overflow from the casting space (50), and then the molten metal is cooled and solidified.

Technical Field

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

Background

In the case of casting a tire molding die, when molten metal is poured into a casting space formed in a mold, if air bubbles are entrained in the molten metal and enter the casting space, the air bubbles stick to the surface of a plaster mold, and air bubble defects occur in a cast product.

Among the casting defects, the blister defect is the most easily generated defect.

As a casting method effective for the bubble defect, there is a low-pressure casting method (for example, see patent document 1).

The low-pressure casting method disclosed in patent document 1 is a method in which a compressed gas is blown into a molten metal stored in a closed holding furnace to pressurize the holding furnace, thereby causing the molten metal to rise through a liquid lifter (stoke) and be poured into a casting space, and very few bubbles are entrained in the molten metal during the pouring.

However, this low-pressure casting method requires a complicated and large dedicated low-pressure casting apparatus, requires a large facility investment, and is also high in manufacturing cost, and it is difficult to cast a large tire molding die.

Further, as a casting method, there is a gravity casting method.

The gravity casting method is a casting method for pouring molten metal into a casting space formed in a mold by gravity from a high position, does not require a large-scale apparatus, and can cast a large-sized tire mold with a suppressed equipment investment and manufacturing cost.

However, in the gravity casting method, bubbles are more likely to be entrained in molten metal during casting than in the low-pressure casting method, and casting defects due to the bubbles are more likely to occur.

Accordingly, there is an example of a gravity casting method in which bubble defects are suppressed by preventing bubbles from entering a casting space as much as possible (see, for example, patent document 2).

Disclosure of Invention

Problems to be solved by the invention

However, in order to float and separate the bubbles entrained in the molten metal in the runner, the flow rate of the molten metal needs to be kept at a constant rate or less, and the time for filling the casting space with the molten metal also inevitably has a lower limit.

If the casting time is long, the transfer of the shape of the plaster cast mold becomes slow, and there are problems that the pressure of the riser head cannot effectively act due to timing delay, and the casting quality is not affected very well in a fine part.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a casting apparatus and a casting method for a tire molding die, which suppress the occurrence of bubble defects, shorten the casting time, and improve the casting quality.

Means for solving the problems

In order to achieve the above object, according to the present invention, there is provided a casting apparatus of a tire molding die, comprising: a platform; an annular gypsum mold disposed above the platform, having a central axis; an outer cylinder mold box disposed above the table, annularly surrounding an outer periphery of the gypsum mold coaxially with the center axis, and forming an annular casting space between the outer cylinder mold box and the gypsum mold; and a casting jig provided on the platform outside the outer cylinder mold box for casting the molten metal into the casting space by gravity, wherein the upper surface of the platform has at least one radiation groove extending in a radiation direction centering on the central axis, a radially outer groove end of the radiation groove has a groove inlet connected to the casting jig at a position outside the outer cylinder mold box for allowing the molten metal to flow into the radiation groove, a radially inner groove end of the radiation groove has a groove outlet on an inner side of the outer cylinder mold box for allowing the molten metal to flow out from the radiation groove into the casting space, and a casting device of the mold for tire molding has a heat insulating cap provided on the casting space, a riser space for storing a riser (Japanese: depression ) is formed right above the groove outlet.

According to this configuration, since the casting apparatus is a gravity casting system in which the molten metal is poured by the pouring jig under the action of gravity to cast the molten metal into the casting space, a large-scale apparatus is not required, the facility investment and the manufacturing cost are suppressed to a low level, and the casting of the mold for forming the large tire can be performed.

Further, since a riser space for storing a riser is formed directly above the spout of the trough by the heat insulating cap disposed above the casting space, bubbles generated in the molten metal during casting enter the radiation trough from the trough inlet, move in the radiation trough, and enter the casting space from the trough outlet, and at this time, almost all of the bubbles are discharged to the outside through the riser in the riser space directly above the trough outlet. Therefore, the condition of air bubbles remaining in the molten metal filled in the casting space can be minimized, and the occurrence of air bubble defects in the cast product can be suppressed.

According to a preferred embodiment of the present invention, the pouring jig includes a sprue cup portion at an upper end and a feed pipe portion extending downward from the sprue cup portion, a lower end of the feed pipe portion is connected to a radially outer groove end portion of the radiation groove of the stage, an inside of the feed pipe portion and the radiation groove communicate with each other via the groove inlet, and the groove inlet is closed by a plug member so as to be freely opened and closed.

According to this configuration, when the groove inlet is opened by the plug member, the molten metal stored in the inside of the feed pipe portion and the sprue cup portion at the upper end of the feed pipe portion by closing the groove inlet by the plug member is drawn into the groove inlet and flows into the radiation groove, and then is poured into the casting space through the radiation groove. Therefore, the generation of bubbles during pouring is less than that when molten metal is poured into the feed pipe portion, and the generation of bubble defects can be further suppressed.

Further, since it is possible to realize that bubble inclusion rarely occurs at the time of casting, there is no need to limit the casting speed, and the casting time can be shortened.

The radiation groove on the upper surface of the platform is a cross gate which is communicated with a groove inlet connected with a pouring jig on the outer side of the outer cylinder mold box and a groove outlet used for enabling molten metal to flow out to a pouring space on the inner side of the outer cylinder mold box.

That is, the radiation grooves are runners that pass through the outer cylinder mold box from the outside to the inside at the shortest distance, and thus the distance is extremely short.

By making the radiation groove (runner) short, the casting time for casting the molten metal into the casting space is shortened.

This makes it possible to improve the casting quality from various aspects such as rapid transfer of the shape of the mold and effective exertion of the pressure of the riser head.

In a preferred embodiment of the present invention, the annular gypsum mold is formed by combining a product mold and a dummy mold in a circumferential direction, and the dummy mold is disposed in the vicinity of the groove outlet.

Since the air bubbles enter the casting space from the spout outlet, the air bubbles are particularly likely to be mixed into the molten metal in the casting space near the spout outlet, but according to the above configuration, the dummy mold is disposed near the spout outlet, and therefore the air bubbles are particularly likely to be mixed into the molten metal corresponding to the dummy mold. However, since the dummy casting portion corresponding to the dummy mold is cut and removed as the dummy portion from the product casting portion, even if air bubbles are mixed into the dummy casting portion, the air bubbles are less likely to be mixed into the product casting portion, and the generation of air bubble defects in the product casting portion can be suppressed to a minimum.

According to a preferred embodiment of the present invention, a casting filter is disposed in the casting space so as to face an outer peripheral surface of a lower end portion of the dummy mold, and the groove outlet is covered with the casting filter.

According to this configuration, since the casting filter disposed in the casting space so as to face the outer peripheral surface of the lower end portion of the dummy mold covers the spout outlet, bubbles and foreign matter are removed by the casting filter from the molten metal flowing out from the spout outlet to the casting space, and the bubbles are more unlikely to be mixed into the product cast portion, so that the generation of bubble defects can be further suppressed, and the foreign matter is also removed, so that the quality of the product cast can be improved.

Further, since the casting filter faces the outer peripheral surface of the lower end portion of the dummy mold, the casting filter is positioned below the dummy casting portion cast corresponding to the dummy mold, and the casting filter can be removed at the same time when the dummy casting portion is cut and removed as a dummy portion from the product casting portion.

In a preferred embodiment of the present invention, the radiation chamber is provided with a weir for restricting the movement of bubbles.

According to this configuration, since the weir for restricting the movement of the bubbles is provided in the radiation tank, the bubbles in the molten metal flowing toward the tank outlet in the radiation tank are intercepted by the weir, so that the bubbles can be prevented from entering the casting space from the tank outlet as much as possible, and the occurrence of bubble defects can be further suppressed.

According to the present invention, there is also provided a method of casting a tire molding die, comprising, when casting the tire molding die using a tire molding die casting apparatus, flowing molten metal into the radiation groove from the groove inlet by the casting jig, flowing the molten metal out of the groove outlet into the casting space, filling the casting space with the molten metal, and further causing a riser to protrude from the casting space, and then cooling and solidifying the molten metal.

According to this method, since the limitation of the casting speed can be eliminated and the casting time can be shortened, the casting quality can be improved from various aspects such as rapid transfer of the shape of the mold and effective exertion of the riser pressure at an early stage.

Further, since the molten metal is poured into the radiation groove from the groove inlet by the pouring jig, and is poured out from the groove outlet to the casting space to be filled in the casting space, the molten metal is filled in the casting space through the short radiation groove passing through the outer cylinder mold box from the outside to the inside.

Further, since almost all of the bubbles that have moved in the radiation tank and entered the casting space from the spout rise into the cap opening directly above the spout and are released, the bubbles are less likely to remain in the molten metal filled in the casting space, and the occurrence of bubble defects can be suppressed.

ADVANTAGEOUS EFFECTS OF INVENTION

The casting apparatus of the present invention is a gravity casting type casting apparatus that uses a casting jig to pour molten metal into a casting space by gravity, and thus does not require a large-scale apparatus, and can reduce equipment investment and manufacturing cost, and can cast a large tire mold.

Further, since the casting speed can be set to be high, the casting time for filling the casting space with the molten metal can be shortened.

Therefore, the casting quality can be improved from various aspects such as rapid transfer of the shape of the mold and effective exertion of the riser pressure at an early stage.

Since a riser space for storing risers is formed directly above the spout of the trough by the heat insulating cap disposed above the casting space, bubbles generated in the molten metal during casting enter the radiation trough from the trough inlet, and almost all the bubbles that have moved in the radiation trough and entered the casting space from the trough outlet rise to the riser of the riser space directly above the trough outlet and are discharged. Therefore, the state in which the bubbles remain in the molten metal filled in the casting space is small, and the occurrence of bubble defects in the cast product can be suppressed.

Drawings

Fig. 1 is an overall perspective view of a casting apparatus of a tire molding die according to an embodiment of the present invention in a state immediately before casting.

Fig. 2 is a vertical sectional view of the casting apparatus of fig. 1 viewed from direction II-II.

Fig. 3 is a perspective view of the platform.

Fig. 4 is an exploded perspective view of the stage and the thermal insulation paper.

Fig. 5 is an exploded perspective view of the stage and the thermal insulation paper.

Fig. 6 is an exploded perspective view of the stage, the mold alignment table, the pressing ring, and the gate member.

Fig. 7 is a perspective view of an assembly in which the stage, the mold alignment table, the pressing ring, and the gate member are combined.

Fig. 8 is a perspective view of an assembly obtained by combining the assembly shown in fig. 7 with a gypsum mold.

Fig. 9 is a perspective view of an assembly in which the thermal cap is assembled to the assembly shown in fig. 8.

Fig. 10 is a perspective view of a combined body obtained by combining the outer cylinder mold box with the combined body shown in fig. 9.

Fig. 11 is a perspective view of an assembly in which the plug member and the opening/closing lever are combined in the assembly shown in fig. 10.

Fig. 12 is a perspective view of an assembly in which the feeder pipe portion and the sprue cup portion are combined with each other in the assembly shown in fig. 11.

Fig. 13 is a vertical cross-sectional view of the casting apparatus after casting.

Fig. 14 is an explanatory view showing a process of manufacturing a tire molding die from a casting cast by the casting device.

Fig. 15 is a perspective view of an assembly of a step of assembling a casting apparatus according to another embodiment.

Fig. 16 is a vertical cross-sectional view of the casting apparatus after casting.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is an overall perspective view of a casting apparatus 1 to which a tire molding die according to an embodiment of the present invention is applied, and fig. 2 is a vertical sectional view of the casting apparatus 1 of fig. 1 viewed from II-II.

The casting apparatus 1 of the tire molding die is a gravity casting type casting apparatus for casting a molten metal into a casting space by pouring the molten metal by gravity using a pouring jig.

Therefore, the casting apparatus 1 does not require a large-scale apparatus like a casting apparatus of a low-pressure casting method, and can cast a large tire mold while suppressing the equipment investment and the manufacturing cost.

The casting apparatus 1 is an apparatus for casting a gypsum casting which is configured in an annular shape by inserting a dummy mold between product molds.

That is, since the product cast portion and the dummy cast portion are alternately formed in the circumferential direction of the cast ring cast, as will be described later, one tire molding die is manufactured by combining a plurality of ring-shaped members with a product cast (product mold half) obtained by dividing the ring cast and removing the dummy cast.

Further, the casting apparatus 1 is a casting apparatus for manufacturing one tire molding die from the product cast of the amount of two annular members.

The structure of the casting apparatus 1 will be described below with reference to fig. 1, which is a perspective view of the entire casting apparatus 1, and fig. 2, which is a sectional view of the casting apparatus 1, and with reference to fig. 3 to 12, which are shown in a substantially assembly order.

Fig. 3 shows the surface plate 2. the surface plate 2 is a cast iron flat plate, and as shown in fig. 3, five positions of the outer peripheral edge of the hollow circular plate, which are equally spaced from each other, protrude radially around the central axis L c of the central circular portion 2a, and have a pentagonal star shape in plan view.

The central annular portion 2a of the platform 2 is recessed on the upper surface thereof compared with the outer peripheral annular portion 2b of the outer periphery thereof.

The outer circumferential annular portion 2b has a pentagonal shape, and five positions on the outer circumferential edge of the outer circumferential annular portion 2b have protruding portions 2bb protruding in the radial direction.

A radiation groove 3 is formed in the upper surface of the outer annular portion 2b of the platform 2 so as to be bored from the vicinity of the inner peripheral edge of the outer annular portion 2b toward each protruding portion 2bb in the radial direction around the central axis L c.

The radially outer slot end 3a of the radiation slot 3 expands cylindrically at the protrusion 2 bb. The radially inner groove end 3b of the radiation groove 3 is close to the inner peripheral edge of the outer annular portion 2 b.

In the casting apparatus 1 of the present embodiment, two radiation grooves 3 out of five radiation grooves 3 of the stage 2 are used as runners, and the other three radiation grooves 3 are filled with a filler 4 (see fig. 4) in advance.

Referring to fig. 4 and 5, heat insulating paper 5a and 5b are attached to the bottom surface and the side wall surface of the radiation groove 3 serving as a runner, respectively. The heat insulating paper 5b is frame-shaped so as to be internally attached to the sidewall surface of the radiation tank 3, and two bar-shaped dam members 6 are provided between the opposing sidewall portions of the frame-shaped heat insulating paper 5b from above.

Referring to fig. 5 and 6, the heat insulating paper 7 covers the upper side of the radiation tank 3 on which the dam member 6 is mounted by the heat insulating papers 5a and 5 b.

A slot inlet 7i having a circular hole is formed at the radial outer end of the heat insulating paper 7 covering the centrifugal-side slot end 3a of the radiation slot 3.

The radially inner end of the heat insulating paper 7 opens a part of the radially inner slot end 3b of the radiation slot 3 as a slot outlet 7e, and covers the other part of the radially inner slot end 3b (see fig. 6).

The heat insulating paper 5a, 5b, 7 is a heat insulating material having excellent heat resistance, which is formed by, for example, forming ceramic fibers into a paper shape.

Next, referring to fig. 6 and 7, a hollow disk-shaped mold alignment table 8, which is a cast iron product, is fitted into the central circular portion 2a of the table 2. When the mold alignment table 8 is fitted into the central annular portion 2a of the table 2, the upper surface of the mold alignment table 8 and the upper surface of the outer annular portion 2b of the table 2 are flush with each other.

Thereafter, the pressing ring 9 is placed on the outer circumferential annular portion 2b of the stage 2.

The press ring 9 is a carbon steel plate, and has an outer peripheral annular portion 9b on the outer periphery of the central annular portion 9a, the outer peripheral annular portion 9b having an outer peripheral edge of the same shape as the outer peripheral annular portion 2b of the platen 2, and five projecting portions 9bb projecting in the radial direction at five positions of the outer peripheral edge, and having a pentagram shape.

A circular hole 9h is formed in a portion of the protruding portion 9bb of the outer annular portion 9b of the pressing ring 9, which corresponds to the radially outer groove end 3a of the radiation groove 3 formed in the outer annular portion 2b of the stage 2.

Gate members 10 are fitted into circular holes 9h of the pressing ring 9 corresponding to the radially outer groove ends 3a of the two radiation grooves 3 serving as runners.

The gate member 10 is made of non-foaming gypsum, and has a cylindrical shape as a whole, a mortar-shaped cylindrical interior is formed, a conical surface 10c tapered downward and inward is formed, and a circular hole 10h is formed through the tip (lower end) of the conical surface 10 c.

The central annular portion 9a of the pressing ring 9 is recessed in the upper surface thereof as compared with the outer peripheral annular portion 9b of the outer periphery thereof. The inner diameter of the central annular portion 9a of the pressing ring 9 is larger than the inner diameter of the outer annular portion 2b of the stage 2.

When the mold alignment table 8 is fitted into the central annular portion 2a of the platen 2 and the press ring 9 is superposed on the outer peripheral annular portion 2b, as shown in fig. 7, the groove outlet 7e of the radially inner groove end 3b of the radiation groove 3 of the platen 2, which is not covered with the heat insulating paper 7, is opened inside the central annular portion 9a of the press ring 9.

When the gate member 10 is fitted into the circular hole 9h of the pressing ring 9, the circular hole 10h at the lower end of the conical surface 10c of the gate member 10 coincides with the groove inlet 7i covering the radially outer end of the heat insulating paper 7 above the radiation groove 3 of the platen 2 (see fig. 2).

Referring to fig. 2, the inner surface of the platen 2 is formed with a runner of molten metal, which flows from a groove inlet 7i aligned with the circular hole 10h of the gate member 10, into the radially outer groove end 3a, flows toward the radially inner groove end 3b, and flows out from a groove outlet 7e of the radially inner groove end 3b, by the radial groove 3 to which the heat insulating papers 5a, 5b, 7 are attached.

Next, as shown in fig. 8, a plaster mold 20 is disposed on the mold alignment table 8 fitted in the center of the table 2, and the plaster mold 20 is formed in an annular shape and mounted with a lining material 25 on the radially inner side. The gypsum mold 20 is formed by alternately combining five product molds 21 and five dummy molds 22 in the circumferential direction.

The five product molds 21 are of the same shape and are located at equally spaced positions in the circumferential direction in the plaster mold 20.

The five dummy molds 22 are also identical in shape and are located at positions equally spaced apart in the circumferential direction in the plaster mold 20.

The dummy mold 22 has an outer diameter smaller than that of the product mold 21.

The five dummy molds 22 are arranged on the mold alignment table 8 in a posture facing the radial direction of the protruding portion 2bb side where the five radiation grooves 3 of the stage 2 are located, and the plaster mold 20 is provided in a posture penetrating the central annular portion 9a of the press ring 9 upward and protruding upward.

Dummy molds 22 corresponding to the two radiation slots 3 serving as runners are disposed in the vicinity of the slot outflow port 7e of the radially inner slot end 3b of the radiation slot 3 (see fig. 2).

The product mold 21 is made of non-foamed gypsum, and a pattern is formed on the outer peripheral surface thereof. The dummy mold 22 inserted between the product molds 21, 21 is made of non-foamed gypsum having a higher density than the product mold 21, and has a large resistance against mold shrinkage.

Next, as shown in fig. 9, a heat insulating cap 30 formed in an annular shape is superimposed on the plaster mold 20. The thermal cap 30 is formed by connecting the inner cylindrical wall 31 and the outer cylindrical wall 32 by a plurality of connecting walls 33 oriented in the radial direction.

Therefore, ten fan-shaped spaces partitioned by the connecting wall 33 are formed between the inner cylindrical wall 31 and the outer cylindrical wall 32, and five dummy spaces 36 are alternately formed in the circumferential direction, the dummy spaces being formed by vertically penetrating feeder head spaces 35 and the bottom of the fan-shaped spaces being closed by the bottom wall 34 (see fig. 2).

Referring to fig. 2, the outer cylindrical wall 32 of the thermal cap 30 has an outer diameter larger than the outer diameters of the five product molds 21 formed in the annular shape and substantially equal to the inner diameter of the central annular portion 9a of the press ring 9.

The outer diameter of the inner cylindrical wall 31 of the thermal cap 30 is substantially equal to the outer diameters of the five ring-shaped dummy molds 22, and the hollow bottom wall 34 is in contact with the upper surface of the plaster mold 20, whereby the thermal cap 30 is supported.

When the heat insulating cap 30 is placed on the plaster mold 20, the heat insulating cap 30 is disposed in a positional relationship in which the feeder head space 35 of the heat insulating cap 30 vertically corresponds to the dummy mold 22 of the plaster mold 20. That is, the feeder head space 35 of the insulated cap 30 is located above the outer space of the dummy mold 22. Heat insulating paper 38 is stuck to the inner wall of the feeder head space 35 of the thermal cap 30.

Next, as shown in fig. 10, the outer cylinder mold box 40 is disposed so as to surround the outer peripheries of the plaster cast 20 and the thermal cap 30. The outer cylinder mold 40 is a cylindrical cast iron product, and the inner diameter of the outer cylinder mold 40 is equal to the outer diameter of the thermal cap 30 and the inner diameter of the central annular portion 9a of the pressure ring 9 (see fig. 2).

The outer cylinder mold 40 has flanges 40U and 40L at its upper and lower ends, respectively, and the flanges 40U and 40L have the same outer diameter and the same inner diameter as the outer annular portion 9b of the press ring 9.

Thus, referring to FIG. 2, the outer cylinder mold 40 is disposed on the central annular portion 9a and is disposed such that the thermal cap 30 is fitted inside, the flange 40L surrounding the outer periphery of the plaster mold 20 and having the lower end is fitted inside the outer annular portion 9b of the press ring 9, the outer cylinder mold 40 is extended to a position above the thermal cap 30, and the heat insulating paper 45 is attached to the inner circumferential surface of the outer cylinder mold 40 facing the plaster mold 20.

As shown in fig. 2, the annular space between the plaster cast 20 and the outer cylinder mold box 40 is a casting space 50.

The upper part of the casting space 50 in the region facing the product mold 21 is partitioned by the bottom wall 34 of the hot top 30, but the space facing the dummy mold 22 in the casting space 50 has a feeder space 35 of the hot top 30 above and communicates with each other vertically.

Since the slot outflow port 7e of the radially inner slot end 3b of the radiation slot 3 opens in the vicinity of the dummy mold 22, the feeder head space 35 is located directly above the slot outflow port 7e, and a feeder head is formed (see fig. 2 and 13).

The radial runner 3 serving as a runner is configured such that the molten metal flows in from the groove inlet 7i on the outer side of the outer cylinder mold 40, passes through the lower side of the outer cylinder mold 40, and flows out from the groove outlet 7e on the inner side of the outer cylinder mold 40 to the casting space 50, and the distance of the runner is short.

Since the groove outlet 7e of the radially inner groove end 3b of the radiation groove 3 opens into the casting space 50 in the vicinity of the dummy mold 22, the molten metal flowing out from the groove outlet 7e enters a space of the casting space 50 facing the dummy mold 22.

Next, a pouring jig 60 is provided for each gate member 10 located above the radially outer groove end portions 3a of the two radial grooves 3 serving as runners (see fig. 12).

As shown in fig. 11, a plug member 61 that comes into contact with the conical surface 10c of the gate member 10 from above to close the circular hole 10h and the groove inlet 7i is provided at the lower end of the opening/closing rod 62.

The plug member 61 is a member having a shape in which the lower end portion of the cylinder protrudes in a conical shape, and is formed by coating the surface of high-carbon steel with ceramic.

An opening/closing lever 62 is connected to the plug member 61, and by lifting the opening/closing lever 62 upward together with the plug member 61, the plug member 61 that closes the groove inlet 7i by coming into contact with the conical surface 10c of the gate member 10 can be lifted upward to open the groove inlet 7 i.

Next, as shown in fig. 12, a cylindrical feeder pipe portion 65 is connected to the gate member 10 in a liquid-tight manner and is provided upright, and a gate cup portion 66 formed in a bowl shape is attached to an upper end of the feeder pipe portion 65. Thus, the casting apparatus 1 assembled into a tire molding die.

Thermal insulation papers 67a and 67b are attached to the inner peripheral surface of the supply pipe portion 65 and the inner surface of the sprue cup portion 66.

Referring to fig. 2, the bottom of the sprue cup 66 is open and communicates with the inside of the feeder pipe portion 65, and when the plug member 61 comes into contact with the conical surface 10c of the sprue member 10 to close the groove inlet 7i, the opening/closing rod 62 connected to the plug member 61 extends upward in the feeder pipe portion 65 and also penetrates the sprue cup 66 to extend upward from the sprue cup 66.

When the molten metal is poured into the sprue cup 66 in a state where the groove inlet 7i is closed by the plug member 61, as shown in fig. 2, the molten metal fills the feeder pipe portion 65 and further fills the sprue cup 66.

Fig. 1 and 2 are an overall perspective view and a vertical cross-sectional view of the casting apparatus 1 in a state where the plug members 61 of the two pouring jigs 60 close the groove inlets 7i and the molten metal (portions where a dotted pattern is drawn) fills the inside of the feed pipe portions 65 and the inside of the sprue cup portions 66.

In the casting apparatus 1, the molten metal used is, for example, an aluminum alloy molten metal.

When the opening and closing rods 62 of the two pouring jigs 60 are gripped and lifted from this state, the respective plug members 61 are integrally lifted, and in the two pouring jigs 60, the groove inflow port 7i is opened, the molten metal accumulated in the charging pipe portion 65 and the sprue cup portion 66 flows into the radiation groove 3 from the groove inflow port 7i by gravity, and the molten metal that has passed through the lower portion of the outer cylinder mold box 40 from the outside to the inside via the runner of the radiation groove 3 flows out to the casting space 50 from the groove outflow port 7e, fills the casting space 50, and further fills the riser space 35 to form a riser.

Fig. 13 is a vertical cross-sectional view of the casting apparatus 1 showing a state in which casting of molten metal is completed.

The radiation groove 3 on the upper surface of the platen 2 is a runner that communicates a groove inlet 7i connected to the pouring jig 60 on the outer side of the outer cylinder mold box 40 and a groove outlet 7e for flowing out the molten metal into the pouring space 50 on the inner side of the outer cylinder mold box 40.

Since the entrainment of air bubbles can be minimized during casting, the casting speed can be increased, and the casting time for casting the molten metal into the casting space 50 can be shortened.

In addition, in the casting apparatus 1, since the two casting jigs 60 are used, the molten metal can be simultaneously cast from the two casting jigs 60 into the casting space 50, and the casting time is shortened. Since the casting time is short, the casting quality can be improved from various aspects such as rapid transfer of the shape of the mold and effective exertion of the riser pressure at an early stage.

Since the riser space 35 of the thermal cap 30 is located directly above the spout outlet 7e of the radially inner spout end portion 3b of the radiation spout 3 to form a riser, bubbles generated in the molten metal during casting enter the radiation spout 3 from the spout inlet 7i, move in the radiation spout 3, and almost all of the bubbles entering the casting space 50 from the spout outlet 7e are discharged to the outside through the riser directly above the spout outlet 7 e. Therefore, the condition of air bubbles remaining in the molten metal filled in the casting space can be minimized, and the occurrence of air bubble defects can be suppressed.

In the casting apparatus 1, the molten metal stored in the inside of the feed pipe portion 65 and the sprue cup portion 66 at the upper end of the feed pipe portion 65 by closing the groove inlet 7i with the plug member 61 of the pouring jig 60 is drawn from the bottom of the feed pipe portion 65 to the groove inlet 7i when the plug member 61 is lifted upward and the groove inlet 7i is opened, flows into the radiation groove 3, and is poured into the pouring space 50 through the radiation groove 3. Therefore, since the bubbles can be floated and separated in advance in the accumulated molten metal, the generation of bubbles during pouring is less than when the molten metal is poured into the feed pipe portion 65, and the generation of bubble defects can be further suppressed.

Further, in the casting apparatus 1, since the weir member 6 for restricting the movement of the bubbles is provided in the radiation tank 3, the bubbles in the molten metal flowing toward the tank outlet 7e in the radiation tank 3 are intercepted by the weir member 6, and the bubbles can be prevented from entering the casting space 50 from the tank outlet 7e as much as possible, thereby further suppressing the occurrence of bubble defects.

The molten metal thus cast is cooled to solidify, and the cast product thus cast has the shape shown in fig. 14 (1) in the as-cast state.

The as-cast product 80 has a shape shown in a flow state of the molten metal shown in a vertical cross-sectional view of the casting apparatus 1 of fig. 13.

In addition, the casting 80 shown in fig. 14 (1) has a casting portion removed from the feeding pipe portion 65 of the pouring jig 60.

Thus, the casting 80 shown in (1) of fig. 14 includes an annular ring casting 81 formed by the casting space 50, a feeder head casting portion 85 formed by the feeder head space 35, and a runner casting portion 86 formed by the two radiation grooves 3 serving as runners.

Since the casting apparatus 1 uses the gypsum mold 20 configured by combining the product mold 21 and the dummy mold 22 in the circumferential direction, five of the annular ring casting 81 are formed so that the product casting portions 82, which are in contact with the product mold 21 and to which the mold surface is transferred, and the dummy casting portions 83, which are in contact with the dummy mold 22, are alternately formed in the circumferential direction. The five product casting portions 82 are of the same shape, and are located at equally spaced positions in the circumferential direction in the ring casting 81.

The feeder head casting portion 85 is formed to protrude upward from the five dummy casting portions 83. The two runner cast portions 86 extend radially from the lower portions of the two dummy cast portions 83, respectively.

The ring casting 81 shown in fig. 14 (2) is formed by cutting two runner casting portions 86 from the ring casting 81 of the as-cast product 80 and cutting five feeder casting portions 85.

In the ring casting 81, five product casting portions 82 and five dummy casting portions 83 are alternately formed in the circumferential direction, and the outer periphery of the dummy casting 22 inside each dummy casting portion 83 is processed by applying an external force from the inside to perform diameter expansion correction, thereby forming a diameter-expanded ring casting 81A shown in fig. 14 (3).

In the diameter-expanding ring casting 81A, product casting portions 82a and dummy casting portions 83a are alternately formed in the circumferential direction and five each are formed. The product cast portion 82a has a slightly larger circumferential width than the dummy cast portion 83 a.

Next, the expanded ring casting 81A is cut at equal intervals in the circumferential direction by a wire electric discharge machine or the like, and divided into ten segments.

As shown in fig. 14 (4), the central portion of the product casting portion 82a of the expanded diameter ring casting 81A excluding both circumferential ends is sheared into a sector of the product die piece 92 a. The dummy mold half including the dummy cast portion 83a as the remaining sector is removed.

In addition, the diameter expansion correction may be performed after the segments are divided.

Since five product mold pieces 92a are cut out from one expanded diameter ring casting 81A, five product mold pieces 92b are cut out from the other expanded diameter ring casting molded similarly, and as shown in fig. 14 (5), the five product mold pieces 92a and the five product mold pieces 92b are combined into a ring shape to assemble one tire molding die 90 shown in fig. 14 (6).

In this way, the tire molding die 90 is manufactured.

As described above, in the ring casting 81 which is a blank of the tire forming mold 90 to be manufactured, the product casting portions 82 and the dummy casting portions 83 are alternately formed in the circumferential direction, five of each, the dummy casting portions 83 being formed by the space of the casting space 50 of the casting device 1 which faces the dummy mold 22, and the dummy mold 22 being disposed in the vicinity of the groove outlet 7e of the radiation groove 3 as shown in fig. 13. Thus, air bubbles are particularly likely to be mixed into 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 divided (divided into sectors) as a dummy portion from the other product casting portions 82 and removed, even if air bubbles are mixed into the dummy casting portion 83, the air bubbles are less likely to be mixed into the product casting portions 82, and the occurrence of air bubble defects in the product casting portions 82 can be suppressed to a minimum.

Further, the feeder head casting portion 85 is provided above the dummy casting portion 83, and most of the bubbles mixed into the molten metal of the dummy casting portion 83 rise in the molten metal of the feeder head casting portion 85 and are discharged to the outside, and the bubbles staying and mixed into the molten metal of the dummy casting portion 83 are not so large.

Next, a casting apparatus 100 according to another embodiment will be described with reference to fig. 15 and 16.

The casting apparatus 100 is obtained by adding a casting filter 110 to the casting apparatus 1.

In the present embodiment, the same reference numerals as those used in the above-described embodiment are used for the reference numerals indicating the members.

The casting filter 110 is, for example, a ceramic foam filter, and has a molten metal straightening function and a function of capturing foreign matter such as metal oxides and nonmetallic inclusions and bubbles in the molten metal. The casting filter 110 is disposed in the casting space 50 so as to cover the tank outlet 7e from above.

As shown in fig. 16, the casting filter 110 is fitted between 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 radiation groove 3 as the runner and the inner peripheral surface of the central annular portion 9a of the pressure ring 9, and as shown in fig. 16: in the casting space 50, the channel outlet 7e is covered from above in contact with the upper surfaces of the stage 2 and the mold arrangement table 8.

The casting filter 110 is provided to extend in the radial direction so as to face and contact 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 spout outlet 7e from above, bubbles and foreign matter are removed from the molten metal flowing out from the spout outlet 7e to the casting space 50 by the casting filter 110, and the bubbles are more difficult to be mixed into the product cast portion 82, so that the generation of bubble defects can be further suppressed, the foreign matter is also removed, and the quality of the cast product can be improved.

Further, 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 in correspondence with the dummy mold 22, and when the dummy casting portion 83 is separated and removed as a dummy portion from the product casting portion 82, the casting filter 110 can be removed at the same time.

The casting apparatus and the casting method according to the embodiments of the present invention have been described above, but the embodiments of the present invention are not limited to the above embodiments, and include embodiments that are implemented in various forms within the scope of the present invention.

For example, the casting apparatus of the present embodiment is provided with two casting jigs, but may be one casting jig, or may be three or more casting jigs.

The more the casting jigs are, the shorter the casting time for casting the molten metal from the casting jigs to the casting space is, and the casting quality can be further improved from various aspects such as rapid transfer of the shape of the mold and effective exertion of the riser pressure at an early stage.

Further, in order to prevent the molten metal from being solidified halfway during casting, the heat insulating paper is not stuck inside the inner surface of a member such as an iron material having a high thermal conductivity with which the molten metal can come into contact, but if the casting time is short, the heat insulating paper can be stuck inside only a desired portion, and the heat insulating paper can be reduced, thereby reducing the cost.

Further, in order to prevent the molten metal from solidifying during casting, it is necessary to heat the mold box or the like, but if the casting time is short, casting can be performed at room temperature, and the cost can be reduced.

In the casting apparatuses 1 and 100 of the above embodiments, the gypsum mold 20 is configured by alternately combining five product molds 21 and five dummy molds 22 in the circumferential direction, but may be configured by only the product molds without dummy molds.

In this case, the tire forming mold is directly cast by the product mold.

Further, the number of product molds and dummy molds constituting the plaster mold may be plural other than five.

Description of the reference numerals

1. The casting device comprises a casting device, a platform, a 2a central circular ring part, a 2b outer circumferential ring part, a 2bb protruding part, a 3 radial groove, a 3a radial inner groove end part, a 3b radial outer groove end part, a 4 filler, a 5a, 5b heat insulation paper, a 6 weir component, a 7 heat insulation paper, a 8 mold arrangement platform, a 9 press ring, a 9a central circular ring part, a 9b outer circumferential ring part, a 9bb protruding part, a 9h round hole, a 10 gate component, a 20 gypsum mold, a 21 product mold, a 22 dummy mold, a 30 heat preservation cap, a 31, an inner cylinder wall, a 32 outer cylinder wall, a 33 connecting wall, a 34, a bottom wall, a 35 riser space, a 36 dummy space, a 38, heat insulation paper, a 40, an outer cylinder box, a 40U, a 40L, a flange, 45, heat insulation paper, a 50, a casting space, a casting jig, a 61, a plug component, a 62, a rod 65, a feeding pipe part 66, an outer cylinder part, a casting box, a 80, a casting ring part, a casting ring forming device, a 80 a, a casting device, a casting ring 80, a casting device, a casting, a dummy mold, a casting device, a dummy mold, a casting, a dummy mold, a casting, a dummy mold, a dummy.