JP3589636B2 - Tire mold - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tire molding die. More specifically, when molding a tire, the occurrence of spews (whisker-like projections) and burr-like protrusions on the tire surface is prevented, and the initial performance and appearance of the obtained tire are maintained in a good state. The present invention relates to a tire molding die capable of reducing the manufacturing cost of the die itself and simplifying the maintenance and inspection work.
[0002]
[Prior art]
Tire molding dies are suitable for forming complicated shapes in response to the fact that the tire design (surface shape) is a complex shape having many sharp corners and thin protrusions called blades. Often manufactured by.
[0003]
The mold for molding a tire manufactured by such casting is usually divided into partial molds, and these partial molds are combined as a whole at the time of tire molding to be used as an entire mold. Such a mold dividing method includes a method of cutting along the circumference in the central axis direction and dividing the mold into 7 to 11 partial molds (upper and lower integrated molds), and a method perpendicular to the central axis ( There is a method of cutting into two partial molds by cutting in the radial direction of the tire (vertical split type), but it can be appropriately selected according to manufacturing conditions and the like.
[0004]
Molding of a tire using such a mold is usually performed by pressing a tire raw material (green tire) made of a polymerized rubber material or the like before molding (before designing) into a mold (compression molding). ).
[0005]
In such a compression molding process, when the green tire is pressed against the mold, a closed space (closed space) is formed between the surface of the mold on which irregularities such as bones and blades are formed and the green tire. Is formed, air is not exhausted from the closed space during molding, and bubbles are included in the finally obtained tire molded product, which causes a problem that a bubble defect called a "bare" is generated.
[0006]
Also, after molding, since the tire mold is roughened due to adhesion of oils and fats during repeated use, it is usually necessary to periodically perform maintenance and inspection such as cleaning. In some cases, this cleaning or the like becomes complicated, and requires a long cleaning operation time, introduction of expensive equipment, and the like, resulting in a problem that the manufacturing cost of a molded article increases.
[0007]
In order to prevent the occurrence of the above-mentioned "bear", it is usually dealt with by taking a method of bleeding air from the mold.
[0008]
Conventionally, two types of venting methods (vent hole type, non spew type or slit vent type) have been adopted.
[0009]
The vent hole type is a method in which an air vent hole (vent hole) communicating with the closed space is provided in the mold, and the air in the closed space is exhausted to the outside through the vent hole. It is inexpensive and has the advantage that a simple blasting method in which media such as glass beads, resin beads, and dry ice pellets are blown with high-pressure air can be employed for maintenance and inspection. However, when the vent hole type is used, the tire raw material (green tire) also flows out into the vent hole with the exhaust of air, so that the final tire molded product (tire product) has a spew (whisker-like). (Protrusions) are formed, and there is also a disadvantage that the appearance and initial running performance as a tire molded product are impaired.
[0010]
Non-spew type or slit vent type is a method of assembling air in a closed space from a gap formed between partial molds or a slit-shaped air vent installed at a predetermined location when a partial mold is assembled into an entire mold. Is advantageous in that it is excellent in appearance as a molded tire and does not hinder the initial running performance. However, in the case of using a non-Spyu type or a slit vent type, spewing can be prevented, but usually it cannot be prevented until the formation of a burr-like protrusion, and the mold itself is not used. Has the disadvantage that the manufacturing cost is high and clogging is likely to occur when the mold is used. In addition to the above, for maintenance and inspection, a simple blast method cannot be adopted unless the mold is disassembled into one partial mold unit (cleaning by blast requires a lot of man-hours). However, it is difficult to remove dirt that has entered the slit due to clogging due to repeated blasting, and special cleaning methods such as chemical cleaning and plasma cleaning have to be used. There is also a disadvantage that time and introduction of expensive equipment are required, and the production cost of the molded article increases.
[0011]
As described above, these two types of air bleeding methods have advantages and disadvantages, respectively. In the end, at present, they are used properly in consideration of the application of the tire, the manufacturing cost, and the like. In other words, when it is necessary to attach importance to the appearance and initial performance of the tire, adopt a non-spew type while accepting an increase in production cost, and attach more importance to the production cost of the mold and the running cost of tire molding. When it is necessary to use the vent hole type mold while accepting the deterioration of the appearance and the initial running performance, the tire appearance, the initial performance, and the production cost This is the reason why satisfying countermeasures are eagerly desired in any of the above.
[0012]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and is obtained by preventing the occurrence of spews (whisker-like projections) and burr-like protrusions on the tire surface when molding a tire in a mold. Provided is a tire molding die capable of maintaining the initial performance and appearance of the tire in a favorable state, reducing the manufacturing cost of the die itself, and simplifying maintenance and inspection work. The purpose is to:
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides the following tire molding die.
[0014]
[1] A tire molding die which is divided into two or more partial dies, and which is used as a whole die by combining these partial dies at the time of tire molding, wherein each of the partial dies is The blockage formed between the green tire and the surface of the partial mold when the tire raw material (green tire) before molding is pressed against each surface of the partial mold to form the tire (during tire molding). An air vent hole (vent hole) capable of discharging air from the space; and a gas vent provided on the surface side of the partial mold of the vent hole, which is chemically inert to the green tire and does not fuse with the green tire. Can be used repeatedly at a temperature of ℃LumberHaving a plurality of circular and / or rectangular through-holes formed of a material.FlexibleAnd a vent tube,The through-hole in the vent tube, linear or curved and regularly or irregularly, having a bent or branched special through shape,When pressing the green tire against each surface of the partial mold to form a tire, it is possible to discharge air in the space in response to an increase in pressure in the space due to the reduction of the closed space. And a tire molding die capable of preventing outflow of the green tire after discharging air.
[0015]
[2]A tire molding die which is divided into two or more partial dies and is used as a whole die by combining these partial dies at the time of tire molding, wherein each of the partial dies is formed before molding. When the tire raw material (green tire) is pressed against each surface of the partial mold to form a tire (at the time of tire molding), air is removed from a closed space formed by the green tire and the surface of the partial mold. Vent holes capable of discharging air, and a temperature of 100 to 200 ° C., which is provided on the surface of the partial mold of the vent hole and is chemically inert to the green tire without fusing. And a flexible vent tube having a plurality of circular and / or rectangular through holes formed of a material that can be used repeatedly in the vent tube. The through-hole, the inner wall surface of which has a special surface shape to which a linear or curved concavo-convex shape is given, or the inner wall surface is roughened, When pressing the green tire against each surface of the partial mold to form a tire, it is possible to discharge air in the space in response to an increase in pressure in the space due to the reduction of the closed space. And a tire molding die capable of preventing outflow of the green tire after discharging air.
[0016]
[3]A tire molding die which is divided into two or more partial dies and is used as a whole die by combining these partial dies at the time of tire molding, wherein each of the partial dies is formed before molding. When the tire raw material (green tire) is pressed against each surface of the partial mold to form a tire (at the time of tire molding), air is removed from a closed space formed by the green tire and the surface of the partial mold. Vent holes capable of discharging air, and a temperature of 100 to 200 ° C., which is provided on the surface of the partial mold of the vent hole and is chemically inert to the green tire without fusing. And a flexible vent tube having a circular and / or rectangular through hole, the flexible vent tube being made of a material that can be used repeatedly in the vent tube. The through hole has a special through shape that is bent or branched in a straight or curved shape and periodically or irregularly, and has a linear or curved uneven shape on its inner wall surface. Or the inner wall surface is roughened, and the green tire is pressed against each surface of the partial mold to form a tire. In this case, it is possible to discharge the air in the space in response to the increase in the pressure in the space due to the reduction of the closed space, and to prevent the outflow of the green tire after discharging the air. A mold for molding a tire, characterized in that:
[0017]
[4] The tire mold according to any one of [1] to [3], wherein the vent tube is made of a silicone-based elastomer or a fluorine-based elastomer.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
[0019]
As shown in FIG. 1A, the tire molding die 10 of the present invention is divided into two or more partial dies 10a, and these partial dies 10a are combined as a whole at the time of tire molding. It is used as a whole mold in the mode shown in FIG. FIG. 1B is a sectional view taken along the line AA. FIG. 1 shows a case in which the upper and lower integrated type is adopted as a method of dividing the mold and the mold is divided into seven pieces along the circumference.
[0020]
In addition, as a material for forming the tire mold of the present invention, for example, an aluminum alloy or an iron-based alloy can be used. Among them, cast aluminum alloys (such as AC4C) and cast irons (such as FCD600) are preferable from the viewpoint of the denseness of the casting and the soundness of the metal structure.
[0021]
As shown in FIG. 2, in the tire molding die of the present invention, each of the partial dies 10 a presses a tire raw material (green tire) 11 before molding onto the surface of each of the partial dies 10 a to form a tire. An air vent (vent hole) 1 for discharging air 13 from a closed space 12 formed by the green tire 11 and the surface of the partial mold 10a during molding (when molding the tire), and a partial mold of the vent hole 1 10a, provided on the surface side, is chemically inert and does not fuse with the green tire 11 and can be repeatedly used at a temperature of 100 to 200 ° C.LumberHaving a plurality of circular and / or rectangular through-holes 20 formed of a material.FlexibleWhen the green tire 11 is pressed against the respective surfaces of the partial molds 10a to form a tire when the green tire 11 is pressed against the surface of the partial mold 10a, the space 12 It is characterized in that it is possible to discharge the inside air 13 and to prevent the outflow of the green tire 11 after discharging the air 13.
[0022]
The size of the air vent hole (vent hole) 1 is not particularly limited as long as the air 13 can be smoothly discharged from the closed space 12 to the outside. It is preferable to set it to 2.0 mm.
[0023]
As shown in FIG. 3, the vent tube 2 has a plurality of circular and / or rectangular through holes 20 in the opening shape.
[0024]
Further, as shown in FIGS. 4A and 4B, the through hole 20 of the vent tube 2 is effective for preventing the green tire 11 from entering or flowing out.Bent or branched, straight or curved and regularly or irregularlyIt has a special penetration shape.
[0025]
As a method of forming such a special penetrating shape in a vent tube, for example, a core having a special surface shape as a core (for example, a thread, a fine wire such as a piano wire) for forming a through hole of a vent tube, or the like. Can be used.
[0026]
With such a configuration, it is possible to obtain a vent tube that discharges air well and makes it difficult for tire raw materials (green tires) to enter the through holes. Also, even when the tire raw material (green tire) enters the through-hole, the resistance to removal when the tire molded product is removed from the tire is small, so that the occurrence of the broken tire raw material (green tire) is effectively prevented. can do.
[0027]
As a specific example of such a special penetrating shape, as shown in FIGS. 4A and 4B, not only a simple linear shape but also one that is bent periodically or irregularly or provided with a branch. Can be mentioned. Although not shown, an angle may be given by forming a curve or the like. In this case, the whole shape of the through hole may be provided with an angle, or the angle may be provided only near the opening.
[0028]
As shown in FIGS. 5A and 5B, the through-hole 20 of the vent tube 2 isOn its inner wall,Effective for preventing intrusion and outflow of green tires 11, With linear or curved irregularitiesIt has a special surface shape.
[0029]
As shown in FIGS. 5A and 5B, a vent tube in which the tire raw material (green tire) is less likely to penetrate into the through hole can be obtained by providing the inner wall surface of the through hole with irregularities. In addition,inner wallThe penetration resistance may be increased by roughening the surface (for example, roughening the surface of the core such as a fine wire by blasting or the like).
[0030]
With this configuration, it is possible to further prevent the tire raw material (green rubber) from entering the inside of the through hole and to suppress the demolding resistance even when the tire raw material (green rubber) enters the through hole. Therefore, it is possible to more effectively prevent the broken green rubber from entering.
[0031]
The tire molding die of the present invention basically has a plurality of through holes 20.,UpA combination of the special through shape and the special surface shape described above or any one of them may be used.Further, one through hole 20 may be used.
[0032]
The vent tube used in the present invention is flexible and, when the tire is formed, is made of a tire raw material (green tire) (for example, natural rubber or butadiene polymer (BR), butadiene / styrene polymer (SBR), etc.). Rubber or a mixture thereof is preferably chemically inert, has no fusion, and has characteristics of being able to be repeatedly used at a temperature of 100 to 200 ° C. Specifically, silicone elastomers, fluorine elastomers, acrylic elastomers, or fluorosilicone elastomersー etc.Can be mentioned as a preferred example. Among them, a silicone-based elastomer or a fluorine-based elastomer is preferable.
[0033]
A vent tube having the above characteristics is, for example,The aboveWhen an elastomer is used, it can be manufactured by cast molding or heat curing molding using a mold. For this reason, in the case of the conventional metal vent tube, it is difficult to cope with the problem. When the surface of the partial mold has a complicated design shape (for example, there is a marking line shape or a sawtooth-shaped convex shape). Case), it can be manufactured relatively easily and inexpensively by casting or heat-curing molding, and the manufacturing cost of the mold itself can be reduced. An air vent mechanism can be installed without damaging the mold surface shape).
[0034]
Moreover, when the vent tube used in the present invention is made of an elastomer, a simple fitting method can be adopted, and the fixing to the partial mold can be simplified. That is, as shown in FIG. 6, the vent tube 2 formed in the same shape is pushed (fitted) into the surface of the vent tube embedding portion by using the undercut shape U produced by casting or machining. It can be easily fixed. Therefore, a special bonding means as in the case of a metal vent tube is not required, and the operation of replacing the vent tube can be simplified, and the manufacturing cost of the mold itself can be reduced.
[0035]
In addition, the vent tube used in the present invention can simplify maintenance and inspection such as cleaning of a mold. In other words, when a conventional metal vent tube is used, if a sand blast method using high-pressure air and abrasive grains is used, property changes and sagging on the surface of the vent tube are likely to occur, and the bent slit shape is long. While it is difficult to maintain, the vent tube used in the present invention can easily open the cut by using the sand blast method, and can easily remove the oil and the like attached to the cut. Can be removed. In the case of the elastomer, there is an advantage that the metal cleaning is more resistant to chemical cleaning using a chemical than the metal.
[0036]
In addition, the vent tube used in the present invention can effectively prevent the occurrence of troubles such as the occurrence of clogging of the rubber burr when the tire is removed from the mold, even in the event that a rubber burr is inserted into the cut of the vent tube during tire molding. It has the advantage that it can be prevented. That is, since the Young's modulus of the vent tube is close to that of the tire rubber material, when the inserted rubber burr is pulled out, if an excessive force acts on the rubber burr, the vent tube itself is also deformed, and the acting force is reduced, and There is an advantage that the occurrence of cutting can be effectively prevented.
[0037]
In this case, in general, as the opening becomes smaller, the air venting performance tends to decrease, and thus the occurrence of “bear” is feared. However, in the present invention, as described above, a plurality of penetration tubes are formed as a vent tube. By using the one in which the holes are formed, it is possible to prevent a decrease in the air release performance.
[0038]
The method for producing the tire molding die of the present invention is not particularly limited, and a generally used method can be used. An example will be described below.
[0039]
FIG. 7 shows a master model (original model) 100 used in manufacturing a tire mold (hereinafter, sometimes referred to as a “mold”). The groove shape and design on the outer surface of such a master model 100 are equivalent to the groove shape and design of a tire product (molded product). In manufacturing a mold, usually, a required number of molds having the master model shape are duplicated and assembled into an annular shape for use.
[0040]
FIG. 8 shows a mold manufacturing process using the master model 100. However, the cross section of the master model 100 in FIG. 8 is more simplified than that shown in FIG.
First, using the master model 100, a rubber mold 114 that is a reversing mold is manufactured (reference numeral 113 indicates a groove) (FIGS. 8A and 8B).
Next, a mold 115 which is a reverse mold of the rubber mold 114 is manufactured (FIG. 8C). The mold 115 is a material that does not deform or damage the rubber mold 114, and is formed of a material that can easily perform casting of a metal material used for the mold, for example, gypsum or ceramic.
Next, using the mold 115, a mold 116, which is an inverted mold thereof, is manufactured by casting (FIG. 8D).
Next, a vent hole 118 is formed by machining using a drill or the like so as to communicate with the outside air from the mold surface to the outside of the mold (FIG. 8E). In the case of drilling, a drill having a two-stage shape (having two kinds of diameters) is used, and the vent tube embedding portion and the vent hole 118 therebelow are produced by one drilling.
Next, the vent tube 119 is inserted into the portion where the vent hole 118 is formed and fixed (FIGS. 8F to 8G). For fixing the vent tube 119, as described above, fitting using an undercut, bonding with an adhesive, or applying a thin metal plate from above the vent tube, and welding this to the mold main body. A method such as fixing can be adopted.
[0041]
In the method for manufacturing a mold described above, the vent hole is formed by machining, but the vent hole can also be formed by a method as shown in FIG. That is, a pin 129 having the same outer diameter as the vent hole 118 formed in the mold 116 is fixed at a predetermined position on the produced mold 115 (FIG. 9A).
The pin 129 must be made of a material that does not melt or fuse with the molten metal during casting for manufacturing the mold 116. For example, in the case of aluminum casting, it is preferable to use steel pins, and in the case of iron and steel casting, it is preferable to use ceramic coated steel pins.
Next, by performing casting with the pin 129 fixed to the mold 115, the pin 129 is taken into the mold 116 from the mold 115 (FIG. 9B).
Next, the vent hole 118 can be easily formed (FIG. 9D) by extracting the pin 129 cast in the mold 116 from the mold 116 (FIG. 9C).
[0042]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited by these Examples.
[0043]
Example 1
An aluminum alloy casting method using a gypsum mold was performed using a mold integrated into upper and lower parts as shown in FIG. 1 and divided into seven parts along the circumference (one part of the mold is composed of seven part molds). (Plaster casting method) (mold material: foamed gypsum and aluminum alloy material AC4C (Si 7%, Cu 0.8%, Mg 0.4%, remaining Al)). In this case, the initial set number of vent holes was 1376 per set.
Next, a vent hole 201 (a diameter of the vent tube embedding portion of 3.0 mm, a height of 5 mm, and a lower hole of 1.6 mm) shown in FIG. 10A was formed by casting in the above manufacturing process. In the mold 200a, five through-holes 300 having a diameter of 0.3 mm shown in FIG. 10B (the five through-holes are formed in a 1.5 × 1.5 mm rectangular area in the center of the cylindrical shape). FIG. 10C shows a vent tube 202 (shape: 3.0 mm in diameter, 5 mm in height, material: additional type silicone rubber manufactured by Toray Silicone Co., Ltd., product name: SH9555) having a vent tube 202 arranged so as to be included. Fitted as shown. The dimensions shown in FIGS. 10A to 10C are all numerical values at room temperature (25 ° C.). When a tire mold having the above-mentioned vent hole structure (vent hole type) was made and the tire was continuously molded, no "bear" was generated and no burr was generated in the vent tube portion. Almost no tire could be molded.
Furthermore, even after about 20,000 tires were formed by continuous molding, the initial air release characteristics could be maintained. In addition, as for the generation of burrs, small ones having a height of about 0.3 mm were generated, but this was a level that hardly caused a problem in appearance quality.
[0044]
Example 2
Example 1 was the same as Example 1 except that the vent tube 202a shown in FIG. 11 was used. As the vent tube 202a, a vent tube 202 (shape: 3.0 mm in diameter, 5 mm in height) having four through holes 300a having a diameter of 0.3 mm (the inside of which is roughened by blasting of # 200). Material: addition-type silicone rubber (trade name: SH9555, manufactured by Toray Silicone Co., Ltd.) was used. When a tire mold having the above-mentioned vent hole structure (vent hole type) was made and the tire was continuously molded, no "bear" was generated and no burr was generated in the vent tube portion. Almost no tire could be molded.
Furthermore, even after about 20,000 tires were formed by continuous molding, the initial air release characteristics could be maintained. In addition, as for the generation of burrs, small ones having a height of about 0.3 mm were generated, but this was a level that hardly caused a problem in appearance quality.
[0045]
【The invention's effect】
As described above, according to the present invention, when molding a tire, the occurrence of spews (whisker-like protrusions) and burr-like protrusions on the tire surface is prevented, and the initial performance and appearance of the obtained tire are prevented. Can be maintained in a favorable state, and a tire molding die capable of reducing the manufacturing cost of the die itself and simplifying the maintenance and inspection work can be provided.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing one embodiment of a tire molding die according to the present invention, wherein (a) is a plan view and (b) is a cross-sectional view taken along line AA.
FIG. 2 is an explanatory view schematically showing one embodiment of a tire molding die of the present invention, in which (a) is a cross-sectional view showing a state in which a vent tube having a plurality of through holes is provided. , (B) is a sectional view taken along the line BB.
FIG. 3 is an explanatory view schematically showing an example of a vent tube having a plurality of through holes used in the present invention.
FIG. 4 is an explanatory view schematically showing an example of a vent tube having a plurality of through holes having a special through shape used in the present invention.
FIG. 5 is an explanatory view schematically showing an example of a vent tube having a plurality of through holes having a special surface shape used in the present invention.
FIG. 6 is a cross-sectional view showing an example of a method of fixing a vent tube used in the present invention to a partial mold, showing a fixing method along an undercut shape.
FIG. 7 is a perspective view schematically showing a master model used in an example of the method for manufacturing a tire molding die of the present invention.
FIG. 8 is a cross-sectional view schematically showing one example of a method for manufacturing a tire molding die of the present invention in the order of steps ((a) to (g)).
FIG. 9 is a cross-sectional view schematically showing another example of the method for manufacturing a tire molding die of the present invention in the order of steps ((a) to (d)).
FIG. 10 is a sectional view and a perspective view schematically showing a partial mold, a vent tube, and an arrangement state thereof used in an embodiment of the tire mold of the present invention.
FIG. 11 is a cross-sectional view schematically showing a vent tube used in another embodiment of the tire molding die of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... vent hole, 2 ... vent tube, 10 ... whole mold (die), 10a ... partial mold, 11 ... tire raw material (green tire), 12 ... closed space, 13 ... air, 20 ... through hole, 100 ... Master model, 100a ... Partial mold, 113 ... Groove, 114 ... Rubber mold, 115 ... Mold, 116 ... Mold, 118 ... Vent hole, 119 ... Vent tube, 129 ... Pin, 200a ... Partial mold, 201 ... Vent holes, 202, 202a: vent tube, 300, 300a: through hole, U: undercut.

Claims (4)

A tire molding die which is divided into two or more partial dies and is used as an entire die by combining these partial dies at the time of tire molding.
When each of the partial molds presses a tire raw material (green tire) before molding onto each surface of the partial mold to form a tire (at the time of tire molding), the green tire and the partial mold are used. An air vent hole (vent hole) through which air can be discharged from a closed space formed by the surface of the green tire, which is provided on the surface side of the partial mold of the vent hole and is chemically inert and fused to the green tire. it repeated use at temperatures of no and 100 to 200 ° C. is composed capable wood charge, the opening shape is provided with a flexible vent tube having a transmural hole of circular and / or rectangular,
The through-hole in the vent tube, linear or curved and regularly or irregularly, having a bent or branched special through shape,
When pressing the green tire against each surface of the partial mold to form a tire, it is possible to discharge air in the space in response to an increase in pressure in the space due to the reduction of the closed space. And a tire molding die capable of preventing outflow of the green tire after discharging air. A tire molding die that is divided into two or more partial dies and is used as an entire die by combining these partial dies at the time of tire molding.
When each of the partial molds presses a tire raw material (green tire) before molding onto each surface of the partial mold to form a tire (at the time of tire molding), the green tire and the partial mold are used. An air vent hole (vent hole) through which air can be discharged from a closed space formed by the surface of the green tire, which is provided on the surface side of the partial mold of the vent hole and is chemically inert and fused to the green tire. A flexible vent tube having a plurality of circular and / or rectangular through-holes, wherein the flexible vent tube is made of a material that can be repeatedly used at a temperature of 100 to 200 ° C.
The through-hole in the vent tube has a special surface shape in which a linear or curved concavo-convex shape is provided on the inner wall surface, or the inner wall surface is roughened. And
When pressing the green tire against each surface of the partial mold to form a tire, it is possible to discharge air in the space in response to an increase in pressure in the space due to the reduction of the closed space. And a tire molding die capable of preventing outflow of the green tire after discharging air. A tire molding die that is divided into two or more partial dies and is used as an entire die by combining these partial dies at the time of tire molding.
When each of the partial molds presses a tire raw material (green tire) before molding onto each surface of the partial mold to form a tire (at the time of tire molding), the green tire and the partial mold are used. An air vent hole (vent hole) through which air can be discharged from a closed space formed by the surface of the green tire, which is provided on the surface side of the partial mold of the vent hole and is chemically inert and fused to the green tire. A flexible vent tube having a circular and / or rectangular through-hole, the opening being formed of a material that can be used repeatedly at a temperature of 100 to 200 ° C.
The through-hole in the vent tube has a straight or curved and regularly or irregularly, a bent or branched special through shape, and, on its inner wall surface, a straight or Either it has a special surface shape to which a curved concavo-convex shape is given, or the inner wall surface is roughened,
When pressing the green tire against each surface of the partial mold to form a tire, it is possible to discharge air in the space in response to an increase in pressure in the space due to the reduction of the closed space. And a tire molding die capable of preventing outflow of the green tire after discharging air. The tire mold according to any one of claims 1 to 3, wherein the vent tube is made of a silicone-based elastomer or a fluorine-based elastomer.

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