JP2019111663A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire that can reduce bareness and also allows a tire inner surface member to be easily arranged at the inner surface of the tire.SOLUTION: Provided is a pneumatic tire in which a plurality of bladder ridges elongating in a tire width direction are formed on the circumference of the tire inner surface, a plurality of projecting parts connecting the bladder ridges are formed among the bladder ridges only in the inner surface from hump parts to bead parts, and a tire inner surface member is arranged at least in a part of the tire width direction of a center part as the tire width direction region among the hump parts of the tire.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire.

  The process of manufacturing a pneumatic tire (hereinafter, also simply referred to as a tire) includes a process of vulcanizing a green tire (unvulcanized tire). In this vulcanization process, a green tire incorporating a tire component is usually placed in a tire vulcanization mold, and the inner cavity of the green tire is further referred to as a tire vulcanization bladder (hereinafter simply referred to as a bladder). A rubber bag is inserted, which consists of a cylindrical ring of circular or horseshoe-shaped cross section. Next, a shaping gas is introduced into the bladder, shaping is performed to bring the inner surface of the green tire into close contact with the bladder, and then high temperature steam such as high temperature steam or high temperature inert gas such as high temperature nitrogen gas inside the bladder. be introduced. As a result, the green tire is strongly pressed against the inner surface of the vulcanizing mold and heated from the inside of the green tire. At the same time, heating is also performed from the outer surface of the green tire by heating the vulcanizing mold with high temperature steam or the like, and vulcanization molding of the tire is performed.

  As such a tire vulcanizing bladder, it is common to use a bladder made of butyl rubber (see, for example, Patent Document 1). Here, butyl rubber chemically reacts with the rubber of the green tire inner surface member in contact with the bladder and adheres. For this reason, when performing a vulcanization | cure process using the bladder which consists of butyl rubber, coating the mold release agent containing a silicon | silicone and a talc on a green tire inner surface is performed.

  However, since a coating machine is used to coat a mold release agent on the inner surface of a green tire, there are problems such as the consumption of materials such as operation energy and coating liquid, and the need to secure an operator's hand. The

  On the other hand, it has also been proposed to use a tire vulcanizing bladder made of fluorine rubber. Since the fluorine rubber does not react chemically with the green tire inner surface member, it is not necessary to coat the inner surface of the green tire with a release agent.

JP, 2014-184579, A

  Here, when the tire is vulcanized using a tire vulcanizing bladder, as shown in FIGS. 7 and 8, before the vulcanization, the bladder and the green tire are provided between the hump portion and the bead portion. In the meantime, a large amount of air is left, and the contact between the green tire and the bladder becomes insufficient, and it has been found that a bear may be generated on the inner surface of the vulcanized tire. In particular, since fluororubber is harder as compared to butyl rubber, such tendency tends to occur as shown in comparison with FIG. 8 in FIG. In addition, tire inner surface members such as noise suppressing members and puncture preventing members may be disposed on the inner surface of the tire that abuts against the tire vulcanization bladder at the time of vulcanization.

  An object of the present invention is to provide a pneumatic tire in which the number of bears is reduced and the tire inner surface member can be easily disposed on the inner surface of the tire.

The essential features of the present invention are as follows.
According to the pneumatic tire of the present invention, a plurality of bladder ridges extending in the tire width direction are formed on the circumference of the inner surface of the tire,
The tire is mounted on a rim, filled with a prescribed internal pressure, and unloaded, from the hump portion to the bead portion which is the region with the smallest radius of curvature in the tire outer contour from the tread surface to the tire maximum width position. On the inner surface only, a plurality of convex portions connecting the bladder ridges are formed between the bladder ridges,
A tire inner surface member is disposed in a tire width direction area of at least a part of a center portion which is a tire width direction area between the hump portions.
According to the pneumatic tire of the present invention, the number of bears can be reduced, and the tire inner surface member can be easily disposed on the tire inner surface.
Here, "bladder ridge" refers to one having a height (maximum height) of 0.3 mm or more under atmospheric pressure.
Moreover, a "convex part" shall mean that whose height (maximum height) is 0.1-0.25 mm under atmospheric pressure.

  In the present specification, “rim” is an industrial standard effective for a region where tires are produced and used, and in Japan, JATMA (Japan Automobile Tire Association) JATMA YEAR BOOK, in Europe ETRTO (The European Tire STANDARDS MANUAL in STANDARDS AND RIM TECHNICAL ORGANIZATION), YEAR BOOK etc. in TRA (The Tire and Rim Association, Inc.) in the US, or standard rims in application sizes described in the future (STANDARDS MANUAL in ETRTO) Measurement Rim refers to Design Rim) in YEAR BOOK of TRA. (That is, the above-mentioned "rim" includes the size that can be included in the above-mentioned industry standard in addition to the current size. An example of "the size described in the future" is ETRTO STANDARDS MANUAL 2013) In the version, mention may be made of the sizes described as “FUTURE DEVELOPMENTS”), but in the case of a size not described in the above-mentioned industry standard, a rim of a width corresponding to the bead width of the tire. Also, the “specified internal pressure” refers to the air pressure (maximum air pressure) corresponding to the tire maximum load capacity of the standards such as the above-mentioned JATMA in the applicable size tire. In addition, in the case of the size which is not described in the said industrial standard, "prescribed internal pressure" shall mean the air pressure (maximum air pressure) corresponding to the maximum load capability specified for every vehicle equipped with a tire.

In the pneumatic tire according to the present invention, the tire inner surface member is preferably a noise suppressing body.
According to this configuration, the quietness of the pneumatic tire can be enhanced.

In the pneumatic tire according to the present invention, the noise suppressing body is preferably made of a sponge material.
According to this configuration, the noiselessness of the pneumatic tire can be effectively improved.

In the pneumatic tire according to the present invention, preferably, the tire inner surface member is a puncture preventing member.
According to this configuration, puncture of the pneumatic tire can be prevented.

In the pneumatic tire according to the present invention, the puncture-preventing member preferably comprises a sealant.
According to this configuration, the puncture of the pneumatic tire can be effectively prevented.

  According to the present invention, it is possible to provide a pneumatic tire in which the number of bears can be reduced and the tire inner surface member can be easily disposed on the tire inner surface.

FIG. 1 is a widthwise sectional view showing a tire vulcanizing bladder that can be used to manufacture a pneumatic tire according to an embodiment of the present invention. It is an expanded view which shows a part of outer surface of a tire vulcanization bladder which can be used for manufacture of a pneumatic tire concerning one embodiment of the present invention. It is sectional drawing which shows a groove part. It is a tire width direction sectional view showing a pneumatic tire concerning one embodiment of the present invention. It is an expanded view which shows a part of tire inner surface of the pneumatic tire concerning one Embodiment of this invention. It is sectional drawing which shows a bladder bridge. It is a figure for demonstrating the flattery nature to the green tire before vulcanization of the tire vulcanization bladder which consists of fluororubber. It is a figure for demonstrating the flattery nature to the green tire before vulcanization of the tire vulcanization bladder which consists of butyl rubber.

  Hereinafter, embodiments of the present invention will be illustrated and described in detail with reference to the drawings. Incidentally, dimensions and the like in the present specification are as in the case of a new product unless otherwise noted.

Tire bladders for vulcanizing tires
FIG. 1 is a cross-sectional view in the width direction showing a tire vulcanizing bladder 1 that can be used to manufacture a pneumatic tire according to an embodiment of the present invention. FIG. 1 shows a schematic cross-sectional shape of a tire vulcanizing bladder 1 in a state of being pressed against the inner surface of an unvulcanized tire. As shown in FIG. 1, the tire vulcanizing bladder 1 (hereinafter simply referred to as a bladder) is a rubber bag made of a tubular ring having a circular or horseshoe-shaped cross section (in the illustrated example, a horseshoe shape). . In this example, the bladder 1 is made of fluororubber (the rubber composition contains fluororubber as a main component). The bladder 1 may be made of another material such as butyl rubber.

FIG. 2 is a developed view showing a part of the outer surface of the tire vulcanizing bladder 1 that can be used to manufacture a pneumatic tire according to an embodiment of the present invention. As shown in FIG. 2, on the circumference of the outer surface of the bladder 1, a plurality of groove portions 2 extending in the width direction are formed. In addition, although the groove part 2 is arrange | positioned at equal intervals in the circumferential direction in this example, you may arrange | position a space | interval. Further, in this example, the groove 2 extends obliquely in the width direction, but may extend in the width direction. Furthermore, in this example, the groove 2 extends linearly in this developed view, but may extend in a curved manner. Also, in this example, the grooves 2 extend continuously, but may extend discontinuously.
Here, the “groove” means one having a depth (maximum depth) of 0.3 mm or more.

  Here, in the bladder 1, in a state where the groove portion 2 is pressed against the inner surface of the unvulcanized tire, five or more groove portions 2 are formed per inch in the circumferential direction at any position in the width direction on the outer surface. Further, in the bladder 1, a plurality of concave portions 3 connecting the groove portions 2 are formed between the groove portions 2 (not shown in FIG. 3). The depth of the recess 3 is 0.1 to 0.25 mm. The recessed part 3 is a random shape which has a part which branched three or more as shown in figure, and has what is called a pebble pattern. The groove 2 and the recess 3 are not shown in FIG.

  In this tire vulcanizing bladder 1, as shown in FIG. 1, in a state where the groove 2 is pressed against the inner surface of the unvulcanized tire, the groove portion 2 is 5 per inch in the circumferential direction at any position in the width direction on the outer surface. It is preferable that the present invention is formed. This is because the stress at the time of vulcanization per one groove portion 2 can be relieved, and the generation and propagation of a crack that can be generated due to the stress can be suppressed.

Further, in the tire vulcanizing bladder 1, it is preferable that 20 or less grooves are formed per 1 inch in the circumferential direction at any position in the width direction on the outer surface. This is because defects in the rubber flow in the vulcanization step can be suppressed.
Further, in the tire vulcanizing bladder 1, it is preferable that 8 or more and 15 or less grooves 2 be formed in one circumferential direction at any position on the outer surface in the width direction. By forming the groove portions 2 eight or more per 1 inch in the circumferential direction, it is possible to further alleviate the concentration of stress per groove portion 2 while, on the other hand, the groove portions 2 are formed 15 times per 1 inch in the circumferential direction It is because the defect of the rubber flow in a vulcanization process can be controlled further by forming below. In the tire vulcanizing bladder 1, it is preferable that ten or more groove portions 2 be formed per inch in the circumferential direction at any position in the width direction on the outer surface. By forming 10 or more grooves 2 per inch in the circumferential direction, it is possible to further alleviate the concentration of stress per groove 2.

FIG. 3 is a cross-sectional view showing the groove 2.
Assuming that the gauge of the tire vulcanization bladder 1 is A (mm) and the depth of the groove 2 is B (mm), the ratio B / A is
0.03 ≦ B / A ≦ 0.15
It is preferable to satisfy
By setting the ratio B / A to 0.03 or more, the quality of the inner surface of the tire can be further improved. On the other hand, by setting the ratio B / A to 0.15 or less, the rigidity against the stress generated in the groove 2 is obtained. As a result, the durability of the bladder 1 can be further improved.
Here, "gauge" refers to the largest gauge, and "depth" refers to the largest depth.

Assuming that 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
It is preferable to satisfy
By setting the ratio B / C to 0.3 or more, the quality of the inner surface of the tire can be further improved. On the other hand, by setting the ratio B / C to 1.0 or less, the rigidity against the stress generated in the groove 2 is obtained. As a result, the durability of the bladder 1 can be further improved.
Here, "the width of the groove portion" means the width between the middle point of the extension direction of the two inflection points of one side wall of the groove portion and the middle point of the extension direction of the two inflection points of the other side wall. It refers to the distance in the direction.

Assuming that the number of grooves 2 in the entire circumference is D (pieces) and the depth of the grooves 2 is B (mm), the ratio B / D is
0.001 ≦ B / D ≦ 0.006
It is preferable to satisfy
By setting the ratio B / D to 0.001 or more, the quality of the inner surface of the tire can be further improved. On the other hand, by setting the ratio B / D to 0.006 or less, the rigidity against the stress generated in the groove 2 is obtained. As a result, the durability of the bladder 1 can be further improved.

Assuming that 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) in the cross section in the extension direction of the groove 2, the ratio B / E is
1.0 ≦ B / E ≦ 5.0
It is preferable to satisfy
By setting the ratio B / E to 1.0 or more, the quality of the inner surface of the tire can be further improved. On the other hand, by setting the ratio B / E to 5.0 or less, the rigidity against the stress generated in the groove 2 is obtained. As a result, the durability of the bladder 1 can be further improved.

  The depth B of the groove 2 is preferably 0.3 to 0.5 mm.

  In the tire vulcanization bladder, the recess 3 is from the hump portion of the finished tire of the green tire of the bladder 1 to the bead portion (the tire diameter direction outermost end of the hump portion to the tire diameter of the bead portion It is provided only in the part which abuts on the inner surface of the part corresponding to the direction innermost end). The stress can be further relieved at the point where the stress is most likely to be concentrated, and the defect of the rubber flow can be suppressed. On the other hand, in the center part of the tire The tire inner surface member such as a body or a puncture preventing member such as a sealant can be easily attached. When the convex portion (the concave portion 3 is transferred) is formed in the center portion, the contact area between the tire inner surface member and the tire inner surface is reduced, and the adhesive force is reduced.

  In the tire vulcanizing bladder, the recess 3 abuts on at least the joint on the carcass ply of the green tire (portion where the carcass ply overlaps) of the circumference of the outer surface of the bladder 1. And it is preferable to be provided in the vicinity. At this position, air is most likely to remain, so it is possible to efficiently suppress the remaining of the air and to suppress the generation of the bear in the tire after vulcanization. For example, the recess 3 may be provided all around the outer surface of the bladder 1.

  As described above, since the recesses 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 be substantially constant on 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 a position where the green tire abuts on the joint on the carcass ply of the carcass ply (portion where the carcass ply overlaps) and the number density in the vicinity thereof. It is preferable to increase from the other places of

<Pneumatic tire>
FIG. 4 is a cross-sectional view in the tire width direction showing the pneumatic tire 10 according to an embodiment of the present invention. As shown in FIG. 4, the tire 10 has a belt layer of one or more layers (two layers in the illustrated example) on the outer side in the tire radial direction of the carcass 12 straddling the bead cores 11 a embedded in the pair of bead portions 11 in a toroidal shape. And a belt protection layer 14 having one or more layers (one layer in the illustrated example), and a tread 15 in this order. Moreover, the bead filler 11b of the cross-sectional triangle shape is arrange | positioned on the tire radial direction outer side of the bead core 11a. The tire of the present invention is not particularly limited as to the structure other than the tire inner surface 16. For example, it may be configured not to have the bead filler 11 b and the belt protection layer 14. Further, the carcass structure and the belt structure are not particularly limited, such as the number of carcass plies, the number of layers of the belt layer and the belt protective layer, and the material of the cord.

The pneumatic tire of the present embodiment is manufactured through a vulcanization process using the tire vulcanization bladder of the above-described embodiment. Therefore, the tire of the present embodiment has one or more particles containing fluorine having a maximum diameter of 1.0 μm or more per 100 μm ² area of the tire inner surface 16. In the tire according to the present invention, as described above, in addition to the bladder made of fluororubber, a bladder made of butyl rubber and the like can also be used, the tire inner surface 16 does not have fluorine particles (less than detection limit). Good.

  FIG. 5 is a developed view showing a part of the tire inner surface 16 of the pneumatic tire according to an embodiment of the present invention. As shown in FIG. 5, in the tire according to the present 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 addition, although the groove part 2 is arrange | positioned at equal intervals in the tire circumferential direction in this example, you may arrange | position a space | interval. Also, 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 rectilinearly in this unfolded view, but may extend curvilinearly. Also, in this example, the bladder ridges 17 extend continuously but may extend discontinuously.

Five or more bladder ridges 17 are formed per inch of tire circumferential direction at any position in the tire width direction of the tire inner surface 16. Further, as shown in FIG. 5, a plurality of convex portions 18 connecting the bladder ridges 17 are formed between the bladder ridges 17 (not shown in FIG. 6). The convex portion 18 is formed only on the inner surface from the hump portion to the bead portion (the outermost end in the tire radial direction of the hump portion to the innermost end in the tire radial direction of the bead portion). Not formed. In the present embodiment, the height of the convex portion 18 is 0.1 to 0.25 mm under atmospheric pressure. The convex portion 18 has a random shape having three or more branched portions as shown, and has a so-called pebble pattern. In addition, at least one of the bladder ridges 17 is formed per inch in the tire circumferential direction at any position in the tire width direction on the inner surface of the bead portion 11. The bladder ridge 17 and the projection 18 are not shown in FIG.
Furthermore, in the tire 10, at least a part of the tire width direction area of the center part which is the tire width direction area between the hump parts (in the present embodiment, an area of 80% of the center of the peripheral length of the tire inner surface of the center part) The tire inner surface member 19 (in the present embodiment, a noise suppressing body made of a sponge material) is disposed. Therefore, the above-mentioned convex part 18 is not formed in the area | region of 10% of both ends of the peripherial length of the tire inner surface of a center part, and the tire inner surface member 19 is not arrange | positioned.
Hereinafter, the operation and effect of the pneumatic tire of the present embodiment will be described.

It has been found that air may remain in the gap between the bladder 1 and the inner surface of the green tire in the tire curing step.
Here, the bladder ridge 17 of the tire 10 is obtained by transferring the groove 2 of the bladder 1, and the convex portion 18 of the tire 10 is obtained by transferring the recessed portion 3 of the bladder 1.
According to the pneumatic tire 10 of the present embodiment, since a plurality of convex portions 18 connecting the bladder ridges 17 are formed between the bladder ridges 17, even when the air remains, a plurality of concave portions are formed. The air can be discharged to the groove 2 through 3 and the air remaining from the groove 2 can be discharged. Therefore, the residual of air is suppressed and the bear of the tire is reduced.
In particular, since the bladder 1 may not sufficiently press at the time of vulcanization from the hump portion of the tire 10 to the inner surface of the bead portion, the remaining of the air is effectively suppressed, and the bear of the tire is reduced.
Furthermore, in the pneumatic tire 10 of the present embodiment, the convex portion 18 is provided only on the inner surface of the bead portion from the hump portion, and the convex portion 18 is not provided on the center portion. It becomes easy to arrange the members 19 (for example, bonding or bonding). This is because when the convex portion (the concave portion 3 is transferred) is formed in the center portion, the contact area between the tire inner surface member 19 and the tire inner surface 16 is reduced and the adhesive force is reduced.
In particular, when the bladder 1 made of fluororubber is used (that is, when one or more particles having a maximum diameter of 1.0 μm or more containing fluorine are included per 100 μm ² area of the tire inner surface 16), the hump portion The above-mentioned air is likely to remain on the inner surface from the tire to the bead portion (the tire radial direction outermost end of the hump portion to the tire radial direction innermost end of the bead portion). can do.
As described above, according to the pneumatic tire 10 of the present embodiment, the number of bears can be reduced, and the tire inner surface member can be easily disposed on the tire inner surface 16.

  Here, in the pneumatic tire 10 of the present invention, as in the above-described embodiment, five or more bladder ridges 17 are formed per inch of tire circumferential direction at any position in the tire width direction of the tire inner surface 16 Is preferred. It is possible to relieve the stress at the time of vulcanization per one groove portion 2 of the bladder 1 used for the vulcanization, and to suppress the generation / progression of cracks which may be caused due to the stress. 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 20 or less of the bladder ridges 17 are formed per inch of the tire circumferential direction at any position in the tire width direction of the tire inner surface 16. It is because it becomes a high quality tire in which the defect of the rubber flow in the vulcanization process is suppressed.
Further, in the pneumatic tire 10 of the present invention, it is preferable that 8 or more and 15 or less of the bladder ridges 17 per inch in the tire circumferential direction be formed at any position in the tire width direction of the tire inner surface 16. By forming at least eight bladder ridges 17 per inch in the circumferential direction, the quality of the tire inner surface 16 can be further improved, while at the same time, fifteen or less bladder ridges 17 are formed in one circumferential direction. This is because defects in the rubber flow in the vulcanization step can be further suppressed. In the pneumatic tire 10 of the present invention, it is preferable that 10 or more bladder ridges 17 are formed in one circumferential direction. This is because the quality of the tire inner surface 16 can be further improved by forming 10 or more bladder ridges 17 per inch in the circumferential direction.
In the present invention, on the inner surface of the bead portion 11, it is preferable that five or more bladder ridges 17 are formed per inch of 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 cross-sectional view showing the bladder ridge 17.
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
It is preferable to satisfy
By setting the ratio B '/ C' to be 0.3 or more, the quality of the inner surface of the tire can be further improved. On the other hand, by setting the ratio B '/ C' to be 1.0 or less, the tire inner surface 16 can be improved. It is possible to further improve the quality of
Here, "the width of the bladder ridge" means the middle point of the extension direction of the two inflection points of one side wall of the bladder ridge under the atmospheric pressure and the extension of the two inflection points of the other side wall It refers to the distance in the width direction from the middle point of the direction, and "height" shall mean the maximum height under atmospheric pressure.

In the present invention, assuming that the number of bladder ridges 17 in the entire circumference is D ′ (book) and the height of the bladder ridge 17 is B ′ (mm), the ratio B ′ / D ′ is
0.001 ≦ B ′ / D ′ ≦ 0.006
It is preferable to satisfy
By setting the ratio B '/ D' to 0.001 or more, the quality of the inner surface of the tire can be further improved. On the other hand, by setting the ratio B '/ D' to 0.006 or less, the tire inner surface 16 can be improved. It is possible to further improve the quality of

In the present invention, when the radius of curvature of the corner of the top of the bladder ridge 17 is E ′ (mm) and the height of the bladder ridge 17 is B ′ (mm) in the cross section in the extension direction of the bladder ridge 17, the ratio B ′ / E 'is
1.0 ≦ B ′ / E ′ ≦ 5.0
It is preferable to satisfy
By setting the ratio B '/ E' to 1.0 or more, the quality of the inner surface of the tire can be further improved. On the other hand, by setting the ratio B '/ E' to 5.0 or less, the inner surface 16 of the tire can be obtained. It is possible to further improve the quality of

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

In the present invention, a plurality of convex portions 18 connecting the bladder ridges 17 are formed between the bladder ridges 17, and the convex portions 18 extend from the hump portion to the bead portion (a tire radial direction outermost end of the hump portion to a bead portion It is formed only on the inner surface of the radial innermost end).
The stress can be further relieved at the portion corresponding to the hump portion and the bead portion where the stress is most likely to be concentrated. Moreover, the defect of a rubber | gum flow can be suppressed and the quality of a tire can be made excellent. Furthermore, the air is likely 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, the tire inner surface member can be easily attached, such as a noise suppressing body such as a sponge material or a puncture preventing member such as a sealant. When the convex portion 18 is formed in the center portion, the contact area between the tire inner surface member 19 and the tire inner surface 16 is reduced, and the adhesive force is reduced.

  In the pneumatic tire according to the present invention, it is preferable that the convex portion 18 be provided at least at the position of the bonding portion on the periphery of the carcass ply on the periphery of the tire inner surface 16 and in the vicinity thereof. It is because a bear can be reduced efficiently as mentioned above. For example, the convex portion 18 can be provided over the entire circumference of the tire inner surface 16.

  As described above, since the convex portions 3 themselves are arranged in a random shape, the shape of the small concave portion is also random. On the other hand, it is preferable that the number density of the small recesses be substantially constant on the entire circumference of the tire inner surface 16. Alternatively, it is preferable to increase the number density more than at other locations on the periphery at least at the position of the joint on the periphery of the carcass ply and on the periphery of the inner surface 16 of the tire.

In the present invention, the tire inner surface member 19 can be disposed in the tire width direction area of at least a part of the tire inner surface 16 in the center portion.
Further, in the present invention, the tire inner surface member 19 can be disposed in at least a partial region on the circumference of the tire inner surface 16. The tire inner surface member 19 is preferably disposed on the entire circumference of the tire inner surface 16.
In the present embodiment, the tire inner surface member 19 is a noise suppressing body made of a sponge material. The sponge material is a sponge-like porous structure, and includes, for example, a so-called sponge having open cells in which rubber or synthetic resin is foamed. In addition to the above-mentioned sponge, the sponge material includes web-like materials in which animal fibers, plant fibers or synthetic fibers are entangled and integrally connected. In addition, the above-mentioned "porous structure" is the meaning including not only the structure which has an open cell but the structure which has a closed cell. The sponge material as described above converts the vibrational energy of the air whose air gap is formed on the surface or inside into the thermal energy. This suppresses cavity resonance in the tire lumen, and as a result, road noise can be reduced. In addition, the sponge material is easy to be deformed such as contraction and bending. Therefore, even if the noise suppressing member formed of the sponge material is fixed to the tread inner surface 16, the deformation of the tire 10 during traveling is not substantially affected. That is, even when the noise suppressing body is fixed to the tread inner surface 16, the steering stability and the like are not easily adversely affected. Examples of the material of the sponge material include synthetic polyurethane resin sponges such as ether polyurethane foam, ester polyurethane foam, polyethylene sponge, chloroprene rubber sponge (CR sponge), ethylene propylene rubber sponge (EPDM sponge), nitrile rubber sponge (NBR sponge) And rubber sponges. It is preferable to use a polyurethane-based or polyethylene-based sponge including an ether-based polyurethane sponge, in view of noise suppression properties, lightness, foam adjustability, durability, and the like. The material constituting the noise suppressing body may be any material that can be controlled to reduce cavity resonance energy by relaxation of cavity resonance energy, absorption, conversion to another energy (for example, thermal energy), etc. The material is not limited to the above-described sponge material, and, for example, urethane or non-woven fabric can also be used. In addition, the specific gravity of the sponge material is preferably set to 0.005 to 0.06, 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 it is particularly preferable to set it to 0.01 to 0.03. Furthermore, the volume of the noise suppressing body is preferably 0.4% to 20% of the total volume of the tire lumen. By securing the volume of the noise suppressing member at 0.4% or more with respect to the entire volume of the tire lumen, it is easy to realize the reduction effect of the desired amount (for example, 2 dB or more) of the cavity resonance energy. The noise suppressing member is more preferably 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 noise suppressing body is configured to exceed 20% of the entire volume of the tire lumen, improvement in the reduction effect of the cavity resonance energy can not be expected. Rather, the weight balance of the assembly may be degraded. From such a point of view, the volume of the noise suppressing member is more preferably 16% or less, and particularly preferably 10% or less of the entire volume of the tire lumen. The above-mentioned volume ratio is not related to the number of noise suppressing members. That is, in the case where there are a plurality of noise suppressing members, similar effects can be obtained as long as the sum of the volumes of all of the plurality of noise suppressing members satisfies the above-described volume ratio relationship.
Furthermore, in the present embodiment, the tire inner surface member 19 is a noise suppressing body, but may be various members such as a puncture preventing member such as a sealant. The sealant can use any known material.
For example, when the tire inner surface member 19 is a noise suppressing body, the noise reduction properties of the tire can be improved, and when the noise reduction body is a sponge material, the noise reduction properties of the tire can be effectively improved. Can. Further, for example, when the tire inner surface member 19 is used as a puncture prevention member, it is possible to prevent a tire from being punctured, and when the puncture prevention member is used as a sealant, it is possible to effectively prevent a tire from being punctured. it can.

As mentioned above, although embodiment of this invention was described, this invention is not limited at all to said embodiment. In particular, the concave portion 3 and the convex portion 18 may have any pebble pattern, as long as they connect between the groove portions 2 from the hump portion to the bead portion or between the bladder ridges 17, and the shape and width The number, etc. are not particularly limited. Also, for example, in the above embodiment, the concave portions 3 and the convex portions 18 have random shapes and arrangement, but some or all of them may have regularity and shapes. Further, the concave portions 3 and the convex portions 18 can be in communication with each other, and the number of the communication (branch) 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 effect of the present invention, a tire vulcanizing bladder made of fluororubber according to the invention example and the comparative example was made on a trial basis. Table 1 shows the specifications of each bladder and the specifications of a tire manufactured using the bladder.
About the above-mentioned invention example and comparative example, the test evaluated about the generation of the bear of a tire was done.

<Bear incidence>
About the manufactured tire, the bear of the tire inner surface was observed visually and the tire which the bear generate | occur | produced was counted. In addition, a "bear" means the defect which a dent remains on the surface by the rubber | gum flow defect.

  As shown in Table 1, it can be seen that in the invention example, the bear is reduced more than in 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 (5)

A pneumatic tire in which a plurality of bladder ridges extending in the tire width direction are formed on the circumference of the inner surface of the tire,
The tire is mounted on a rim, filled with a prescribed internal pressure, and unloaded, from the hump portion to the bead portion which is the region with the smallest radius of curvature in the tire outer contour from the tread surface to the tire maximum width position. On the inner surface only, a plurality of convex portions connecting the bladder ridges are formed between the bladder ridges,
A pneumatic tire characterized in that a tire inner surface member is disposed in at least a part of a tire width direction area of a center part which is a tire width direction area between the hump parts.   The pneumatic tire according to claim 1, wherein the tire inner surface member is a noise suppressing body.   The pneumatic tire according to claim 2, wherein the noise suppressing body is made of a sponge material.   The pneumatic tire according to claim 1, wherein the tire inner surface member is a puncture prevention member. The pneumatic tire according to claim 4, wherein the puncture preventing member comprises a sealant.

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