JP7209802B2 - Bladder for tire vulcanization and pneumatic tire - Google Patents

Description

The present invention relates to tire vulcanizing bladders and pneumatic tires.

A manufacturing process of a pneumatic tire (hereinafter also simply referred to as a tire) includes a process of vulcanizing a raw tire (unvulcanized tire). In this vulcanization process, a green tire having tire components incorporated therein is usually placed in a tire vulcanization mold, and a tire vulcanization bladder (hereinafter simply referred to as a bladder) is placed in the inner cavity of the green tire. A rubber bag consisting of a cylindrical ring of circular or horseshoe-shaped cross-section is inserted. Next, a shaping gas is introduced into this bladder, and shaping is performed so that the inner surface of the raw tire and the bladder are brought into close contact with each other. be introduced. As a result, the green tire is strongly pressed against the inner surface of the vulcanization mold and heated from the inside of the green tire. At the same time, by heating the mold for vulcanization with high-temperature steam or the like, the outer surface of the raw tire is also heated, and vulcanization molding of the tire is performed.

As such a tire vulcanizing bladder, a bladder made of butyl rubber is generally used (see, for example, Patent Document 1). Here, the butyl rubber chemically reacts with the rubber of the raw tire inner surface member that is in contact with the bladder and adheres to it. Therefore, when performing a vulcanization process using a bladder made of butyl rubber, the inner surface of a green tire is coated with a release agent containing silicon or talc.

However, since a coating machine is used to apply the release agent to the inner surface of the raw tire, there are problems such as consumption of materials such as operating energy and coating liquid, and the need to secure workers. rice field.

On the other hand, it has been proposed to use a tire vulcanizing bladder made of fluororubber. Since the fluororubber does not chemically react with the raw tire inner surface member, there is no need to apply a release agent to the inner surface of the raw tire.

JP 2014-184579 A

However, as shown in FIG. 7 in comparison with the case of butyl rubber in FIG. 8, since fluororubber is harder than butyl rubber, before vulcanization, between the hump portion and the bead portion, during shaping, the bladder and the green tire are hardened. It was found that a large amount of air remains between the tire and the bladder, resulting in insufficient contact between the green tire and the bladder, which may cause bares to occur on the inner surface of the tire after vulcanization.

Accordingly, the present invention provides a tire vulcanizing bladder that can suppress the occurrence of bareness in a tire after vulcanization, and aims to reduce bareness in a pneumatic tire manufactured using the tire vulcanizing bladder. aim.

The gist and configuration of the present invention are as follows.
The tire vulcanizing bladder of the present invention is made of fluororubber,
A plurality of grooves extending in the width direction are formed on the circumference of the outer surface of the tire vulcanizing bladder,
A plurality of recesses connecting the grooves are formed between the grooves.
According to the tire vulcanizing bladder of the present invention, it is possible to suppress the generation of bare tires after vulcanization.
Here, the "groove part" shall mean a thing with a depth (maximum depth) of 0.3 mm or more.
The "recessed portion" has a depth (maximum depth) of 0.1 to 0.25 mm.

The pneumatic tire of the present invention has one or more fluorine-containing particles with a maximum diameter of 1.0 μm or more per 100 μm ² region of the tire inner surface,
A plurality of bladder ridges extending in the tire width direction are formed on the circumference of the tire inner surface,
A plurality of protrusions connecting between the bladder ridges are formed between the bladder ridges.
According to the pneumatic tire of the present invention, bears can be reduced.
Here, "bladder ridge" refers to a ridge having a height (maximum height) of 0.3 mm or more under atmospheric pressure.
Further, the "protrusion" is defined as having a height (maximum height) of 0.1 to 0.25 mm under atmospheric pressure.

In the pneumatic tire of the present invention, the convex portion has a radius of curvature on the tire outer contour line from the tread surface to the maximum width position of the tire when the tire is mounted on the rim, filled with a specified internal pressure, and in an unloaded state. It is preferable that it is formed only from the inner surface of the hump portion, which is the smallest area, to the inner surface of the bead portion.
According to this configuration, it is possible to more effectively reduce bears.

As used herein, the term "rim" refers to an industrial standard valid for the region where tires are produced and used, such as JATMA (Japan Automobile Tire Manufacturers Association) JATMA YEAR BOOK in Japan and ETRTO (The European Tire and Rim Technical Organization), and in the United States, TRA (The Tire and Rim Association, Inc.) YEAR BOOK, etc., or standard rims in applicable sizes that will be described in the future (ETRTO's STANDARDS MANUAL Measuring Rim, Design Rim in TRA's YEAR BOOK). (That is, the above "rim" includes not only current sizes but also sizes that may be included in the above industrial standards in the future. Examples of "sizes to be described in the future" include ETRTO's STANDARDS MANUAL 2013 The size listed as "FUTURE DEVELOPMENTS" in the version can be mentioned), but if the size is not listed in the above industrial standard, it means a rim with a width corresponding to the bead width of the tire. In addition, the "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum tire load capacity of the standard such as JATMA in the tire of the applicable size. In the case of sizes not listed in the above industrial standards, the "specified internal pressure" refers to the air pressure (maximum air pressure) corresponding to the maximum load capacity specified for each vehicle on which the tire is mounted.

According to the present invention, it is possible to provide a tire vulcanizing bladder that can suppress the generation of bareness in a tire after vulcanization, and to reduce bareness in a pneumatic tire manufactured using the tire vulcanizing bladder. can be done.

1 is a cross-sectional view in the width direction showing a tire vulcanizing bladder according to an embodiment of the present invention; FIG. 1 is an exploded view showing part of the outer surface of a tire vulcanizing bladder according to an embodiment of the present invention; FIG. It is a cross-sectional view showing a groove. BRIEF DESCRIPTION OF THE DRAWINGS It is a tire width direction sectional drawing which shows the pneumatic tire concerning one Embodiment of this invention. 1 is an exploded view showing part of the tire inner surface of a pneumatic tire according to an embodiment of the present invention; FIG. FIG. 3 is a cross-sectional view showing a bladder ridge; FIG. 3 is a diagram for explaining the followability of a tire vulcanizing bladder made of fluororubber to a raw tire before vulcanization. FIG. 3 is a diagram for explaining the followability of a tire vulcanizing bladder made of butyl rubber to a raw tire before vulcanization.

Embodiments of the present invention will be exemplified in detail below with reference to the drawings. The dimensions and the like in this specification are those of a new product unless otherwise specified.

<Tyre vulcanizing bladder>
FIG. 1 is a cross-sectional view in the width direction showing a tire vulcanizing bladder 1 according to one embodiment of the present invention. FIG. 1 shows a schematic cross-sectional shape of a tire vulcanizing bladder 1 pressed against the inner surface of an unvulcanized tire. As shown in FIG. 1, this tire vulcanizing bladder 1 (hereinafter also referred to simply as a bladder) is a rubber bag made of a cylindrical ring having a circular or horseshoe-shaped cross section (horseshoe-shaped in the illustrated example). . The bladder 1 of the present embodiment is made of fluororubber (a rubber composition containing fluororubber as a main component).

FIG. 2 is a developed view showing a part of the outer surface of the tire vulcanizing bladder 1 according to one embodiment of the present invention. As shown in FIG. 2, a plurality of grooves 2 extending in the width direction are formed on the circumference of the outer surface of the bladder 1 . In this example, the grooves 2 are arranged at equal intervals in the circumferential direction, but they may be arranged at different intervals. Also, in this example, the groove portion 2 extends obliquely in the width direction, but may extend along the width direction. Furthermore, in this example, the groove portion 2 extends linearly in this developed view, but it may extend curvedly. Moreover, although the groove 2 extends continuously in this example, it may extend discontinuously.

Here, in the bladder 1 of the present embodiment, in a state of being pressed against the inner surface of the unvulcanized tire, the grooves 2 are formed at any position in the width direction on the outer surface at least five per inch in the circumferential direction. ing. In addition, in the bladder 1 of the present embodiment, a plurality of recesses 3 connecting between the grooves 2 are formed between the grooves 2 (illustration is omitted in FIG. 3). In this embodiment, the depth of the recess 3 is 0.1 to 0.25 mm. As shown, the recess 3 has a random shape with three or more branched portions, forming a so-called pebble pattern. Note that the groove 2 and the recess 3 are omitted from FIG.
The effects of the tire vulcanizing bladder 1 of this embodiment will be described below.

It has been found that, in the tire vulcanization process, air may remain in the gap between the bladder 1 and the inner surface of the raw tire because the fluororubber does not stretch easily.
According to the tire vulcanizing bladder 1 of the present embodiment, since a plurality of recesses 3 connecting the grooves 2 are formed between the grooves 2, even if the air remains, a plurality of Air can escape to the groove 2 through the recess 3, and the remaining air can be discharged from the groove 2. - 特許庁As a result, it is possible to suppress the remaining air and suppress the generation of bareness in the vulcanized tire.
According to the tire vulcanizing bladder 1 of the present embodiment, it is possible to suppress the occurrence of bareness in the tire after vulcanization, and the tire after vulcanization has reduced bareness.

In the tire vulcanizing bladder 1 of the present invention, as in the above-described embodiment, when the groove 2 is pressed against the inner surface of the unvulcanized tire, the groove 2 is positioned at any position in the width direction on the outer surface, It is preferable that 5 or more are formed per inch. This is because the stress during vulcanization per one groove portion 2 can be relaxed, and the occurrence and propagation of cracks that may be caused by the stress can be suppressed.

Further, in the tire vulcanizing bladder 1 of the present invention, it is preferable that the groove portions 2 are formed at any position in the width direction on the outer surface at 20 or less per inch in the circumferential direction. This is because it is possible to suppress poor rubber flow in the vulcanization process.
Moreover, in the tire vulcanizing bladder 1 of the present invention, it is preferable that the grooves 2 are formed at any position in the width direction on the outer surface at a number of 8 or more and 15 or less per inch in the circumferential direction. By forming eight or more grooves 2 per inch in the circumferential direction, stress concentration per groove 2 can be further alleviated, while 15 grooves 2 are formed per inch in the circumferential direction. This is because by forming below, it is possible to further suppress poor rubber flow in the vulcanization process. In the tire vulcanizing bladder 1 of the present invention, it is preferable that 10 or more grooves 2 are formed per inch in the circumferential direction at any position in the width direction on the outer surface. This is because, by forming ten or more grooves 2 per inch in the circumferential direction, stress concentration per groove 2 can be further alleviated.

FIG. 3 is a cross-sectional view showing the groove portion 2. As shown in FIG.
In the present invention, when the gauge of the tire vulcanizing bladder 1 is A (mm) and the depth of the groove portion 2 is B (mm), the ratio B/A is
0.03≤B/A≤0.15
is preferably satisfied.
By setting the ratio B/A to 0.03 or more, the quality of the inner surface of the tire can be further improved. is ensured, and the durability of the bladder 1 can be further improved.
Here, "gauge" shall refer to the maximum gauge, and "depth" shall refer to the maximum depth.

In the present invention, when the width of the groove 2 is C (mm) and the depth of the groove 2 is B (mm), the ratio B/C is
0.3≤B/C≤1.0
is preferably satisfied.
By setting the ratio B/C to 0.3 or more, the quality of the inner surface of the tire can be further improved. is ensured, and the durability of the bladder 1 can be further improved.
Here, the "width of the groove" is the width between the midpoint in the extending direction of the two inflection points on one side wall of the groove and the midpoint in the extending direction of the two inflection points on the other side wall of the groove. It shall refer to the distance in the direction.

In the present invention, when the number of grooves 2 on the entire circumference is D (number) and the depth of the grooves 2 is B (mm), the ratio B/D is
0.001≤B/D≤0.006
is preferably satisfied.
By setting the ratio B/D to 0.001 or more, the quality of the inner surface of the tire can be further improved. is ensured, and the durability of the bladder 1 can be further improved.

In the present invention, when the curvature radius of the corner of the bottom of the groove 2 is E (mm) and the depth of the groove 2 is B (mm), the ratio B/E is ,
1.0≤B/E≤5.0
is preferably satisfied.
By setting the ratio B/E to 1.0 or more, the quality of the inner surface of the tire can be further improved. is ensured, and the durability of the bladder 1 can be further improved.

In the present invention, the depth B of the groove 2 is preferably 0.3 to 0.5 mm.

In the tire vulcanizing bladder of the present invention, the concave portion 3 extends from the hump portion of the finished tire to the bead portion (from the tire radial direction outermost end of the hump portion to the bead portion). It is preferable that it is provided only in a portion that abuts on the inner surface of the portion corresponding to the innermost end in the tire radial direction. The stress can be further relieved at the location where the stress is most likely to be concentrated, and the rubber flow failure can be suppressed. Furthermore, this is also a location where air tends to remain, and the remaining air can be effectively discharged from the groove 2 via the recess 3 . On the other hand, in the center portion of the tire, it is possible to easily attach tire inner surface members such as a sound damping body such as a sponge material and a puncture prevention member such as a sealant. This is because when the center portion is formed with a convex portion (to which the concave portion 3 is transferred), the contact area between the tire inner surface member and the tire inner surface decreases, resulting in a decrease in adhesive strength.

In the tire vulcanizing bladder of the present invention, the recessed portion 3 corresponds to at least the joint portion (the portion where the carcass ply overlaps) on the circumference of the carcass ply of the raw tire on the circumference of the outer surface of the bladder 1. It is preferable that they are provided at the contacting position and the vicinity thereof. This is because air is most likely to remain on the circumference at this position, and thus the remaining air can be efficiently suppressed, thereby suppressing the generation of bareness in the tire after vulcanization. For example, the recess 3 can be provided over the entire circumference of the outer surface of the bladder 1 .

As described above, since the concave portions 3 themselves are arranged in a random shape, the shape of the small land portion is also random. On the other hand, it is preferable that the number density of the small land portions is substantially constant along the entire circumference of the outer surface of the bladder 1 . Alternatively, on the circumference of the outer surface of the bladder 1, at least at the position where the green tire abuts the joint portion (the portion where the carcass ply overlaps) on the circumference of the carcass ply and in the vicinity thereof, the number density is is preferably increased more than at other locations.

<Pneumatic tire>
FIG. 4 is a cross-sectional view in the tire width direction showing the pneumatic tire 10 according to one embodiment of the present invention. As shown in FIG. 4, the tire 10 has one or more belt layers (two layers in the illustrated example) on the outer side in the tire radial direction of a carcass 12 that toroidally straddles bead cores 11a embedded in a pair of bead portions 11. , one or more belt protective layers 14 (one layer in the illustrated example), and a tread 15 in this order. A bead filler 11b having a triangular cross-section is arranged outside the bead core 11a in the tire radial direction. The structure of the tire of the present invention other than the tire inner surface 16 is not particularly limited. For example, a configuration without the bead filler 11b and the belt protection layer 14 is also possible. Further, the number of carcass plies, the number of belt layers and belt protective layers, the material of cords, and the like, and the carcass structure and belt structure are not particularly limited.

The pneumatic tire of this embodiment is manufactured through a vulcanization process using the tire vulcanizing bladder of the above embodiment. Therefore, the tire of this embodiment has one or more fluorine-containing particles with a maximum diameter of 1.0 μm or more per 100 μm ² region of the tire inner surface 16 .

FIG. 5 is a developed view showing part of the tire inner surface 16 of the pneumatic tire according to one embodiment of the present invention. As shown in FIG. 5, in the tire of this embodiment, a plurality of bladder ridges 17 extending in the tire width direction are formed on the circumference of the tire inner surface 16 . In this example, the grooves 2 are arranged at equal intervals in the tire circumferential direction, but they may be arranged at different intervals. Further, in this example, the bladder ridge 17 extends obliquely in the tire width direction, but may extend along the tire width direction. Furthermore, in this example, the bladder ridge 17 extends linearly in the developed view, but it may extend curvedly. Moreover, although the bladder ridge 17 extends continuously in this example, it may extend discontinuously.

Five or more bladder ridges 17 are formed per inch in the tire circumferential direction at any position on the tire inner surface 16 in the tire width direction. Further, as shown in FIG. 5, a plurality of protrusions 18 connecting between the bladder ridges 17 are formed between the bladder ridges 17 (illustration is omitted in FIG. 6). The convex portion 18 is formed only on the inner surface from the hump portion to the bead portion (from the outermost end of the hump portion in the tire radial direction to the innermost end of the bead portion in the tire radial direction), and the inner surface of the center portion, which is the region therebetween. not formed in In this embodiment, the height of the projection 18 is 0.1 to 0.25 mm under atmospheric pressure. As shown, the convex portion 18 has a random shape with three or more branched portions, forming a so-called pebble pattern. In particular, five or more bladder ridges 17 are formed per inch in the tire circumferential direction at any position on the inner surface of the bead portion 11 in the tire width direction. Note that the bladder ridge 17 and the projection 18 are omitted in FIG. 4 .
Furthermore, in the tire 10, at least a partial tire width direction area of the center portion, which is the tire width direction area between the hump portions (in this embodiment, an area of the central 80% of the periphery length of the tire inner surface of the center portion). A tire inner surface member 19 (in this embodiment, a noise damper made of a sponge material) is arranged. Therefore, the protrusions 18 are not formed and the tire inner surface member 19 is not arranged in the areas corresponding to 10% of the periphery length at each end of the inner surface of the tire in the center portion.
The effects of the pneumatic tire of this embodiment will be described below.

It has been found that, in the tire vulcanization process, air may remain in the gap between the bladder 1 and the inner surface of the raw tire because the fluororubber does not stretch easily.
Here, the bladder ridge 17 of the tire 10 is obtained by transferring the groove portion 2 of the bladder 1 , and the convex portion 18 of the tire 10 is obtained by transferring the concave portion 3 of the bladder 1 .
According to the pneumatic tire 10 of the present embodiment, since the plurality of protrusions 18 connecting the bladder ridges 17 are formed between the bladder ridges 17, even if the air remains, the plurality of recesses 3, the air could escape to the groove portion 2, and the remaining air could be discharged from the groove portion 2. Therefore, residual air is suppressed, and tire bareness is reduced.
According to the pneumatic tire 10 of this embodiment, bears can be reduced.

Here, in the pneumatic tire 10 of the present invention, five or more bladder ridges 17 are formed per inch in the tire circumferential direction at any position on the tire inner surface 16 in the tire width direction, as in the above-described embodiment. preferably. It is possible to relax the stress during vulcanization per groove 2 of the bladder 1 used for vulcanization, suppress the occurrence and propagation of cracks that may occur due to the stress, and improve the pneumatic tire 10. This is because the quality of the tire inner surface 16 is excellent.

Here, in the pneumatic tire 10 of the present invention, it is preferable that no more than 20 bladder ridges 17 are formed per inch in the tire circumferential direction at any position of the tire inner surface 16 in the tire width direction. This is because a high-quality tire in which poor rubber flow in the vulcanization process is suppressed can be obtained.
Moreover, in the pneumatic tire 10 of the present invention, it is preferable that the bladder ridges 17 are formed at any position on the tire inner surface 16 in the tire width direction in an amount of 8 or more and 15 or less per inch in the tire circumferential direction. By forming eight or more bladder ridges 17 per inch in the circumferential direction, the quality of the tire inner surface 16 can be improved, while forming 15 or less bladder ridges 17 per inch in the circumferential direction. This is because it is possible to further suppress poor rubber flow in the vulcanization process. In the pneumatic tire 10 of the present invention, it is preferable that 10 or more bladder ridges 17 are formed per inch in the circumferential direction. This is because the quality of the tire inner surface 16 can be further improved by forming ten or more bladder ridges 17 per inch in the circumferential direction.
In the present invention, it is preferable that five or more bladder ridges 17 are formed on the inner surface of the bead portion 11 per 1 inch in the tire circumferential direction on the circumference. This is because the quality of the tire inner surface 16 can be further improved.

FIG. 6 is a sectional view showing the bladder ridge 17. As shown in FIG.
In the present invention, when the width of the bladder ridge 17 is C' (mm) and the height of the bladder ridge 17 is B' (mm), the ratio B'/C' is
0.3≤B'/C'≤1.0
is preferably satisfied.
By setting the ratio B'/C' to 0.3 or more, the quality of the tire inner surface can be further improved. This is because the quality of the product can be further improved.
Here, the "width of the bladder ridge" means the midpoint in the extending direction of the two inflection points on one side wall of the bladder ridge under atmospheric pressure and the extending direction of the two inflection points on the other side wall. "Height" refers to the maximum height under atmospheric pressure.

In the present invention, when the number of bladder ridges 17 on the entire circumference is D' and the height of the bladder ridges 17 is B' (mm), the ratio B'/D' is
0.001≤B'/D'≤0.006
is preferably satisfied.
By setting the ratio B'/D' to 0.001 or more, the quality of the tire inner surface can be further improved. This is because the quality of the product can be further improved.

In the present invention, when the curvature radius of the top corner of the bladder ridge 17 is E' (mm) and the height of the bladder ridge 17 is B' (mm), the ratio B'/E' is
1.0≤B'/E'≤5.0
is preferably satisfied.
By setting the ratio B'/E' to 1.0 or more, the quality of the tire inner surface can be further improved. This is because the quality of the product can be further improved.

In the present invention, the height B' of the bladder ridge 17 is preferably 0.3 to 0.5 mm in the case of a passenger car tire, for example.

In the present invention, a plurality of protrusions 18 connecting the bladder ridges 17 are formed between the bladder ridges 17, and the protrusions 18 extend from the hump portion to the bead portion (from the tire radial direction outermost end of the hump portion to the bead portion of the tire). preferably formed only on the inner surface up to the radially innermost end).
The stress can be further relieved in the portions corresponding to the hump portion and the bead portion where the stress is most likely to concentrate. In addition, it is possible to suppress poor rubber flow, and to improve the quality of the tire. Furthermore, this is also a location where air tends to remain, and the remaining air can be effectively discharged from the groove 2 via the recess 3 . On the other hand, in the center portion of the tire 10, it is possible to easily attach a tire inner surface member such as a sound damping body such as a sponge material and a puncture prevention member such as a sealant. This is because the contact area between the tire inner surface member 19 and the tire inner surface 16 is reduced when the convex portion 18 is formed in the center portion, thereby lowering the adhesive force.
In the present invention, the position of the convex portion 18 is not necessarily limited to the case where it is formed only at the above-mentioned position.

In the pneumatic tire of the present invention, the protrusions 18 are preferably provided at least on the circumference of the tire inner surface 16 at the position of the joint on the circumference of the carcass ply and in the vicinity thereof. This is because bears can be efficiently reduced in the same manner as described above. For example, the convex portion 18 can also be provided over the entire circumference of the tire inner surface 16 .

As described above, since the projections 3 themselves are arranged in a random shape, the shape of the small recesses is also random. On the other hand, it is preferable that the number density of the small recesses is substantially constant along the entire circumference of the tire inner surface 16 . Alternatively, on the circumference of the tire inner surface 16, it is preferable to increase the number density at least at the positions of the joints on the circumference of the carcass ply and in the vicinity thereof, compared to other locations on the circumference.

In the present invention, the tire inner surface member 19 can be arranged at any position on the tire inner surface 16 in the tire width direction. For example, when arranging on the inner surface of the center portion, the tire inner surface member 19 can be arranged on a part or all of the area of the center portion.
Further, in the present invention, the tire inner surface member 19 can be arranged in at least a partial region on the circumference of the tire inner surface 16 . The tire inner surface member 19 is preferably arranged on the entire circumference of the tire inner surface 16 .
In this embodiment, the tire inner surface member 19 is a noise damper made of a sponge material. The sponge material is a sponge-like porous structure, and includes, for example, a so-called sponge having continuous cells formed by foaming rubber or synthetic resin. In addition to the above-described sponge, the sponge material includes a web-like material in which animal fibers, vegetable fibers, synthetic fibers, or the like are intertwined and connected together. In addition, the above-mentioned "porous structure" is not limited to a structure having open cells, but also includes a structure having closed cells. The sponge material as described above converts the vibrational energy of the air vibrating in the voids formed on its surface and inside into thermal energy. As a result, cavity resonance in the tire cavity is suppressed, and as a result, road noise can be reduced. Moreover, the sponge material is easily deformed such as by shrinking and bending. Therefore, even if the noise damper made of a sponge material is fixed to the tire inner surface 16, it does not substantially affect deformation of the tire 10 during running. In other words, even if the sound damping body is fixed to the tire inner surface 16, the steering stability and the like are unlikely to be adversely affected. Examples of sponge materials include synthetic resin sponges such as ether-based polyurethane sponges, ester-based polyurethane sponges, polyethylene sponges, chloroprene rubber sponges (CR sponges), ethylene propylene rubber sponges (EPDM sponges), and nitrile rubber sponges (NBR sponges). ) and other rubber sponges. From the viewpoints of sound damping, light weight, controllability of foaming, durability, etc., it is preferable to use a polyurethane-based or polyethylene-based sponge including an ether-based polyurethane sponge. It should be noted that the material constituting the sound damping body may be any material that can be controlled to reduce the cavity resonance energy by relaxation, absorption, conversion to other energy (for example, thermal energy), etc. The material is not limited to the sponge material described above, and for example, urethane or non-woven fabric can also be used. Further, the specific gravity of the sponge material is preferably 0.005 to 0.06, more preferably 0.01 to 0.04, in consideration of the balance between the increase in tire weight and the effect of suppressing cavity resonance. is more preferable, and 0.01 to 0.03 is particularly preferable. Furthermore, the volume of the sound damper is preferably 0.4% to 20% of the total volume of the tire lumen. By ensuring that the volume of the sound damping body is 0.4% or more with respect to the total volume of the tire lumen, it is easy to achieve the effect of reducing the cavity resonance energy by a desired amount (for example, 2 dB or more). More preferably, the noise damper accounts for 1% or more, more preferably 2% or more, and particularly preferably 4% or more of the total volume of the tire lumen. On the other hand, even if the volume of the sound damping body exceeds 20% of the total volume of the tire cavity, an improvement in the effect of reducing cavity resonance energy cannot be expected. Rather, it may deteriorate the weight balance of the assembly. From this point of view, the volume of the noise damper is more preferably 16% or less, particularly preferably 10% or less, of the total volume of the tire lumen. Note that the above-mentioned volume ratio is not related to the number of damping bodies. That is, when there are a plurality of sound damping bodies, the same effect can be obtained if the sum of the volumes of all the sound damping bodies satisfies the above-described volume ratio relationship.
Furthermore, in the present embodiment, the tire inner surface member 19 is a sound damper, but it can be other various members such as a puncture prevention member such as a sealant. If a sealant is used, it can be of any known material.
For example, when the tire inner surface member 19 is a noise damper, the quietness of the tire can be improved, and when the noise damper is a sponge material, the quietness of the tire can be effectively improved. can be done. Further, for example, when the tire inner surface member 19 is used as a puncture prevention member, tire puncture can be prevented, and when the puncture prevention member is used as a sealant, tire puncture can be effectively prevented. can.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. In particular, the concave portion 3 and the convex portion 18 can have any pebble pattern as long as they connect between the groove portions 2 and between the bladder ridges 17, and the shape, width, number, etc. are particularly limited. not. Further, for example, in the above embodiment, the concave portions 3 and the convex portions 18 are randomly shaped and arranged, but some or all of them may be shaped and arranged with regularity. Further, the concave portions 3 and the convex portions 18 can communicate with each other, and the number of connections (branching) is not particularly limited.
Examples of the present invention will be described below, but the present invention is not limited to the following examples.

In order to confirm the effects of the present invention, prototype tire vulcanizing bladders made of fluororubbers according to Invention Examples 1 and 2 and Comparative Example were produced. Table 1 shows the specifications of each bladder and the specifications of tires manufactured using the bladders.
A test was conducted to evaluate the occurrence of tire bareness on the invention examples 1 and 2 and the comparative example.

<Bear occurrence rate>
The produced tires were visually observed for bareness on the inner surface of the tire, and the number of tires with bareness was counted. The term "bare" refers to a defect in which a dent remains on the surface due to poor rubber flow.

As shown in Table 1, it can be seen that invention examples 1 and 2 have less bareness than the comparative example.

1: tire vulcanizing bladder, 2: groove, 3: recess,
10: pneumatic tire, 11: bead portion, 11a: bead core,
11b: bead filler, 12: carcass, 13: belt, 14: belt protective layer,
15: Tread 16: Tire inner surface 17: Bladder ridge 18: Convex portion
19: tire inner surface member

Claims (6)

A tire vulcanizing bladder made of fluororubber,
A plurality of grooves extending in the width direction are formed on the circumference of the outer surface of the tire vulcanizing bladder,
A plurality of recesses connecting between the grooves are formed between the grooves,
The groove has a depth of 0.3 to 0.5 mm,
When the radius of curvature of the bottom corner of the groove is E (mm) and the depth of the groove is B (mm), the ratio B/E is
satisfying 1.0 ≤ B / E ≤ 5.0,
A bladder for vulcanizing a tire, characterized in that all said grooves extend parallel to each other and each said groove does not cross another said groove . The tire vulcanizing bladder according to claim 1, wherein the recess has a depth of 0.1 to 0.25 mm. When the number of the grooves on the entire tire circumference is D (number) and the depth of the grooves is B (mm), the ratio B/D is
0.001≤B/D≤0.006
The tire vulcanizing bladder according to claim 1 or 2, which satisfies: The recess is provided only in a portion of the tire vulcanizing bladder that contacts the inner surface of the portion corresponding to the hump portion to the bead portion of the finished tire of the raw tire. 4. The tire vulcanizing bladder according to any one of 3. When the gauge of the tire vulcanizing bladder is A (mm) and the depth of the groove is B (mm), the ratio B/A is
0.03≤B/A≤0.15
The tire vulcanizing bladder according to any one of claims 1 to 4, which satisfies When the width of the groove is C (mm) and the depth of the groove is B (mm), the ratio B/C is
0.3≤B/C≤1.0
The tire vulcanizing bladder according to any one of claims 1 to 5, which satisfies

Images