Pneumatic tire and method for repairing pneumatic tire

Abstract

To provide a pneumatic tire that is improved in external damage resistance of a sidewall, eliminates the need of discarding a tire even when a sidewall is externally damaged, and is economically and environmentally preferable, and to provide a method for repairing a pneumatic tire.SOLUTION: A sidewall 20 includes a nonwoven fabric sheet 25 disposed on a tire axial outside of a sidewall rubber 21 and including a nonwoven fabric and a rubber adhering to the nonwoven fabric. The nonwoven fabric sheet 25 is disposed so as to include a tire maximum width position 20W and form an outside surface 20c of the sidewall 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pneumatic tire to be mounted on a vehicle and a method for repairing the pneumatic tire. [Background technology]

[0002] When a pneumatic tire is mounted on a vehicle, the tread that comes into contact with the road surface and the sidewall that constitutes the side of the tire are the main exposed parts, but the sidewall generally has lower strength, hardness, etc. than the tread. If the sidewall is damaged by contact with, for example, a curb or rock, it is likely to cause a puncture, so it is preferable that the sidewall has appropriate strength, hardness, etc., but on the other hand, there is a limit because the ride comfort is deteriorated. Patent Document 1 discloses a pneumatic tire in which a filament fiber rubber composite made of a nonwoven fabric and a rubber composition is embedded inside the sidewall to reinforce the sidewall while ensuring ride comfort. [Prior art documents] [Patent documents]

[0003] [Patent Document 2] JP 2002-79811 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the sidewall of a pneumatic tire is hit hard by a curb, rock, or the like and is severely damaged to the extent that the internal carcass ply is severed, the tire cannot be used because the internal pressure cannot be maintained even if the tread has a sufficient functional life. According to the above-mentioned Patent Document 1, the rigidity of the sidewall is improved, but there is no mention of resistance to external damage. Even if the tread has a sufficient life, a situation in which the tire must be discarded due to damage to the sidewall is economically or environmentally undesirable, and measures are required.

[0005] Therefore, an object of the present invention is to provide a pneumatic tire and a method for repairing a pneumatic tire, which improves the resistance of the sidewall to external damage, does not require the tire to be discarded even if the sidewall is damaged, and is economical and environmentally preferable. [Means for solving the problem]

[0006] The pneumatic tire of the present invention is a pneumatic tire comprising: a pair of beads including a bead core and a bead filler extending radially outward from the bead core; a sidewall extending radially outward from the pair of beads, including sidewall rubber, and including a maximum tire width position; a tread disposed between the pair of sidewalls and including tread rubber; and a carcass ply bridged between the pair of beads and embedded inside the tire, the carcass ply being disposed axially inward of the sidewall rubber in the sidewall, wherein the sidewall is disposed axially outward of the sidewall rubber, and includes a nonwoven fabric sheet having a nonwoven fabric and rubber adhered to the nonwoven fabric, and the nonwoven fabric sheet is disposed so as to form an outer surface of the sidewall including the maximum tire width position.

[0007] The method for repairing a pneumatic tire of the present invention is a method for repairing the above-mentioned pneumatic tire of the present invention, and includes a removal step of removing the nonwoven fabric sheet, and a placement step of placing a new nonwoven fabric sheet on the surface of the sidewall rubber exposed after the nonwoven fabric sheet has been removed, the placement step including a preparation step of preparing, as the new nonwoven fabric sheet, a nonwoven fabric sheet in which the rubber to be adhered to the nonwoven fabric is in an unvulcanized state, a step of attaching the new nonwoven fabric sheet to the surface of the sidewall rubber, and a vulcanization step of vulcanizing the unvulcanized rubber of the new nonwoven fabric sheet.

[0008] The method for repairing a pneumatic tire of the present invention is a method for repairing the above-mentioned pneumatic tire of the present invention, and includes a removal step of removing the nonwoven fabric sheet, and a placement step of placing a new nonwoven fabric sheet on the surface of the sidewall rubber exposed after the nonwoven fabric sheet has been removed, the placement step including a preparation step of attaching the vulcanized rubber to the nonwoven fabric to prepare the new nonwoven fabric sheet, and an attachment step of attaching the new nonwoven fabric sheet to the surface of the sidewall rubber via an adhesive material. Effect of the Invention

[0009] According to the present invention, it is possible to provide a pneumatic tire and a method for repairing a pneumatic tire, which improves the resistance of the sidewall to external damage and eliminates the need to discard the tire even if the sidewall is externally damaged, and is economical and environmentally favorable. [Brief description of the drawings]

[0010] [Figure 1] 1 is a half cross-sectional view in an axial direction of a pneumatic tire according to an embodiment. FIG. [Diagram 2] FIG. 4 is a half cross-sectional view in the tire axial direction showing a modified example of the pneumatic tire according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment will be described with reference to Fig. 1. Fig. 1 shows a cross section in the tire axial direction of a tire 1, which is a pneumatic tire for a vehicle according to the embodiment. The tire 1 is a tire for a passenger car. Note that the configuration of the tire 1 of the embodiment can also be applied to tires for various vehicles such as light trucks, trucks, and buses.

[0012] The cross-sectional view of FIG. 1 is a cross-sectional view of a tire 1 mounted on a standard rim (not shown) and inflated to a standard internal pressure in an unloaded state. The standard rim is a rim that is determined for each tire by a standard system including the standard on which the tire is based, for example, a standard rim for JATMA, and a "Measuring Rim" for TRA and ETRTO. The standard internal pressure is an air pressure determined for each tire by each standard in a standard system including the standard on which the tire is based, and in the case of tires for trucks and buses and tires for light trucks, it is the maximum air pressure for JATMA, the maximum value listed in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" for TRA, and "INFLATION PRESSURE" for ETRTO. For tires for passenger cars, it is usually 180 kPa, but for tires marked "Extra Load" or "Reinforced", it is 220 kPa.

[0013] The basic structure of the tire 1 is symmetrical in a cross section in the tire axial direction. Fig. 1 shows a cross section of the right half of the tire 1, and the left half (not shown) has the same structure. In Fig. 1, the symbol S1 indicates the tire equatorial plane. The tire equatorial plane S1 is a plane perpendicular to the tire rotation axis and located at the center in the tire axial direction.

[0014] Here, the tire axial direction is a direction parallel to the tire rotation axis, and is the left-right direction on the paper in Fig. 1. In Fig. 1, this is illustrated as the tire axial direction X. The tire axially inner side is a direction approaching the tire equatorial plane S1, and is the left side on the paper in Fig. 1. The tire axially outer side is a direction away from the tire equatorial plane S1, and is the right side on the paper in Fig. 1.

[0015] The tire radial direction is a direction perpendicular to the tire rotation axis, and is the up-down direction on the paper in Fig. 1. In Fig. 1, this is illustrated as tire radial direction Y. The outer side in the tire radial direction is a direction away from the tire rotation axis, and is the upper side on the paper in Fig. 1. The inner side in the tire radial direction is a direction approaching the tire rotation axis, and is the lower side on the paper in Fig. 1.

[0016] As shown in FIG. 1, the tire 1 includes a pair of beads 10, a pair of sidewalls 20 extending radially outward from each of the pair of beads 10, a tread 30 disposed between the pair of sidewalls 20, a shoulder 40 which is a transition portion from the sidewalls 20 to the tread 30, a carcass ply 50 disposed spanning between the pair of beads 10, and an inner liner 60 disposed on the tire cavity side of the carcass ply 50.

[0017] The pair of beads 10 are disposed on both axial sides of the tire and on the inner ends in the tire radial direction. The bead 10 has a bead core 11, a bead filler 12 extending from the bead core 11 to the outer side in the tire radial direction, a chafer 13, and a rim strip rubber 14.

[0018] The bead core 11 is an annular member in which a rubber-coated metal bead wire is wound multiple times in the tire circumferential direction. The bead core 11 is a member that serves to fix the tire 1 filled with air to the rim. The bead filler 12 has a tapered shape that decreases in thickness as it extends from the tire radial inner side to the tire radial outer side. The bead filler 12 is provided to increase the rigidity of the peripheral portion of the bead 10 and ensure high maneuverability and stability. The bead filler 12 is made of, for example, rubber that is harder than the surrounding rubber members. The bead filler 12 is joined to the tire radial outer surface of the bead core 11.

[0019] The chafer 13 is provided in a manner to further surround the outside of the carcass ply 50 which surrounds the bead core 11 and the bead filler 12 .

[0020] The rim strip rubber 14 is disposed on the axially outer side of a part of the carcass ply 50 and the chafer 13, and further extends to the vicinity of the radially inner side of the chafer 13. The rim strip rubber 14 has a rim line 15c that protrudes axially outward of the tire. The rim line 15c is a circular line that runs along the tire circumferential direction. The rim line 15c is a mark for matching the edge of the rim. When the edge of the rim is matched with the rim line 15c over the entire circumference, the tire 1 is determined to be correctly mounted on the rim. The rim strip rubber 14 including the rim line 15c constitutes a rim protector 15 that is disposed to protrude axially outward from the rim.

[0021] The sidewall 20 includes a sidewall rubber 21 arranged axially outward of the carcass ply 50, and a nonwoven fabric sheet 25 arranged axially outward of the sidewall rubber 21.

[0022] As described above, the radially inner end 21a of the sidewall rubber 21 constitutes the rim protector 14 that covers a part of the carcass ply 50 and the axially outer side of the chafer 13, and has a rim line 15c. The sidewall rubber 21 is the part that bends the most when the tire 1 performs its cushioning function, and flexible rubber having fatigue resistance is usually used for it.

[0023] The sidewall rubber 21 has a recess 22 on the outer surface side of the tire. The recess 22 extends over the entire circumference in the tire circumferential direction. The tire axial cross section of the sidewall rubber 21 has a curved shape that is convex toward the tire axial outside. The recess 22 is formed along the curved shape. The tire radial inner edge of the recess 22 is preferably formed by the above-mentioned rim line 15c. The tire radial outer end 21b of the sidewall rubber 21 has a protruding end 21d that protrudes toward the tire axial outside in the same manner as the rim line 15c. The tire radial outer edge of the recess 22 is preferably formed by the protruding end 21d. Both ends of the recess 22 in the tire radial direction are formed into a gently curved R-shape.

[0024] The recess 22 has a length of, for example, 70% to 90% of the length (also called the periphery length) along the curved shape of the sidewall rubber 21 in the tire axial cross section. In the direction of the periphery length, the vicinity of the center of the recess 22 almost coincides with the vicinity of the center of the sidewall rubber 21. Due to the formation of the recess 22, the thickness of the sidewall rubber 21 at both ends in the tire radial direction is greater than the thickness of the portion where the recess 22 is formed. Furthermore, the thickness of the portion of the sidewall rubber 21 corresponding to the recess 22 gradually increases from the center toward both ends in the periphery length direction in the tire axial cross section.

[0025] The nonwoven fabric sheet 25 constitutes a part of the sidewall 20 in a manner to be accommodated in the recess 22. An outer surface 25c of the nonwoven fabric sheet 25 is along a profile line which forms the outer surface of the entire sidewall 20. In other words, the outer surface 25c of the nonwoven fabric sheet 25 forms the outer surface 20c of the sidewall 20. The nonwoven fabric sheet 25 is a constituent element which characterizes the present invention, and will be described in detail later.

[0026] The tread 30 includes an endless belt 31, a cap ply 34, and a tread rubber 35. The belt 31 is disposed on the outer side of the carcass ply 50 in the tire radial direction. The cap ply 34 is disposed on the outer side of the belt 31 in the tire radial direction. The tread rubber 35 is disposed on the outer side of the cap ply 34 in the tire radial direction.

[0027] The belt 31 is a member that reinforces the tread 30. The belt 31 of the embodiment has a two-layer structure including an inner belt 32 arranged on the outer side of the inner liner 60 in the tire radial direction, and an outer belt 33 arranged on the outer side of the inner belt 32 in the tire radial direction. Both the inner belt 32 and the outer belt 33 have a structure in which a plurality of belt cords such as steel cords are covered with rubber. The inner belt 32 is wider than the outer belt 33. By providing the belt 31, the rigidity of the tire 1 is ensured, and the contact of the tread 30 with the road surface is improved. Note that the belt 31 is not limited to a two-layer structure, and may have a single layer structure, or a three-layer structure or more.

[0028] The cap ply 34 is a member that reinforces the tread 30 together with the belt 31. The cap ply 34 has a structure in which a plurality of insulating organic fiber cords such as polyamide fiber are covered with rubber. The cap ply 34 is wider than the belt 31 and covers the entire belt 31 from the tire outer surface side. By providing the cap ply 34, it is possible to improve the durability of the tire 1 and reduce road noise during running. Note that the cap ply 34 is not limited to a single-layer structure as in the embodiment, but may have a two-layer structure or a three-layer structure or more.

[0029] The tread rubber 35 is disposed on the outer side of the cap ply 34 in the tire radial direction. The tread rubber 35 forms a tread surface 36, which is the outer surface of the tread 30 and comes into contact with the road surface. A plurality of main grooves 36a extending along the tire circumferential direction are formed in the tread surface 36 at intervals in the tire axial direction. An end 35a on the outer side of the tread rubber 35 in the tire axial direction protrudes outward in the tire axial direction from the end of the outer side of the cap ply 34 in the tire axial direction and bends inward in the tire radial direction, covering the end 21b on the outer side of the sidewall rubber 21 in the tire radial direction. The tread rubber 35 has a tip 35b on the inner side in the tire radial direction. The tip 35b of the tread rubber 35 is disposed in a state where it substantially coincides with a protruding end 21d formed on the end 21b on the outer side of the sidewall rubber 21 in the tire radial direction.

[0030] The shoulder 40 includes a portion of the tread rubber 35 that extends from a portion covering the axially outer end of the cap ply 34 to the axially outer end 35a of the tire. A buttress 70 including grooves 71 and protrusions 72 that extend along the tire circumferential direction is formed on the outer surface of the region extending from the shoulder 40 to the sidewall 20. The buttress 70 is formed in the tread rubber 35.

[0031] The carcass ply 50 is embedded in the tire 1 in a manner that passes between a pair of beads 10, a pair of sidewalls 20, a pair of shoulders 40, and the tire cavity side of the tread 30. In the tread 30, a belt 31 is disposed on the outer side of the carcass ply 50 in the tire radial direction.

[0032] The carcass ply 50 includes a ply main body portion 51 extending from the tread 30 through a pair of shoulders 40 and each of a pair of sidewalls 20 toward the axially inner side of each of a pair of beads 10, and a pair of turned-up portions 52 that are wound from the ply main body portion 51 around each of a pair of bead cores 11 and extend radially outward from the ply main body portion 51.

[0033] The ply main body portion 51 is disposed in the tread 30 on the radially inner side of the belt 31 in the tire radial direction, and is disposed in the sidewall 20 on the axially inner side of the sidewall rubber 21 .

[0034] The turned-up portion 52 is disposed axially outward of the bead core 11 and the bead filler 12, and further extends radially outward from the bead filler 12 to near the radial center of the sidewall 20. A portion of the turned-up portion 52 radially outward of the bead filler 12 is overlapped on the axially outward side of the ply body portion 51. A turned-up end 52a, which is the radially outward tip of the turned-up portion 52, is located radially inward of the maximum width position 20W of the tire 1 included in the sidewall 20.

[0035] The chafer 13 of the bead 10 described above surrounds the end of the carcass ply 50 on the inner side in the tire radial direction, the end winding around the bead core 11 .

[0036] The carcass ply 50 has a configuration in which a plurality of ply cords arranged in parallel are covered with rubber. The ply cords are made of insulating organic fiber cords such as polyester or polyamide, and function as the framework of the tire 1.

[0037] Although the carcass ply 50 in the embodiment has a single layer structure, the carcass ply 50 may have a multi-layer structure of two layers or three or more layers. A single layer structure is preferable in terms of weight reduction.

[0038] The inner liner 60 forms the tire cavity surface by covering the inner surface of the ply body portion 51 of the carcass ply 50 and the axially inner portion of the chafer 13 between the pair of beads 10. The inner liner 60 is made of air-resistant rubber and prevents air in the tire cavity from leaking to the outside.

[0039] Here, the rubber used for the bead filler 12 has a hardness higher than at least the sidewall rubber 21 and the inner liner 60. The hardness of the rubber is a hardness tested according to "JIS K6253-3:2012 durometer hardness type A".

[0040] For example, when the hardness of the sidewall rubber 21 is used as a standard, the hardness of the bead filler 12 is preferably about 1.2 to 2.3 times the hardness of the sidewall rubber 21. By setting the hardness at such a level, it is possible to ensure a balance between the flexibility of the tire and the rigidity in the vicinity of the bead 10.

[0041] As described above, the nonwoven fabric sheet 25 is accommodated in the recess 22 of the sidewall rubber 21 to form the sidewall 20, and its outer surface 25c is aligned along the outer surface 20c of the entire sidewall 20. The nonwoven fabric sheet 25 is disposed so as to form the outer surface 20c of the sidewall 20 including the tire maximum width position 20W of the sidewall 20.

[0042] The nonwoven fabric sheet 25, being accommodated in the recess 22, has a length that is, for example, about 70% to 90% of the periphery length of the sidewall rubber 21. In the direction of the periphery length, the vicinity of the center of the nonwoven fabric sheet 25 almost coincides with the vicinity of the center of the sidewall rubber 21.

[0043] The nonwoven fabric sheet 25 has a nonwoven fabric and rubber attached to the nonwoven fabric. An example of the rubber attached to the nonwoven fabric is that impregnated in the nonwoven fabric. In that case, it is preferable that the surface layer is covered with rubber. In another embodiment, a sheet-like nonwoven fabric formed into a sheet of a predetermined thickness may be covered with a topping rubber. In that case, it is preferable that the topping rubber is thinner than the nonwoven fabric. In any case, it is preferable that the outer surface 25c of the nonwoven fabric sheet 25 is formed of rubber. In addition, it is preferable that the back surface of the nonwoven fabric sheet 25 facing the sidewall rubber 21 is also formed of rubber in order to increase adhesion with the sidewall rubber 21.

[0044] The nonwoven fabric of the nonwoven fabric sheet 25 is, for example, a felt-like sheet, and the fibers constituting the nonwoven fabric are not oriented, but rather oriented randomly. A nonwoven fabric having randomly oriented fibers is preferable because it results in a sheet with higher strength with fewer gaps between the fibers compared to one having an orientation.

[0045] The thickness of the nonwoven fabric sheet 25 of the embodiment is preferably 3 mm or more. The thickness of the nonwoven fabric sheet 25 is more preferably 3 mm or more and 9 mm or less. This is because if the thickness is less than 3 mm, the external damage resistance that protects against external damage may be insufficient, and if it exceeds 9 mm, excessive mass increase occurs. When the thickness of the nonwoven fabric sheet 25 is 3 mm or more and 9 mm or less, both improvement of external damage resistance and suppression of mass increase are achieved.

[0046] Examples of the material of the nonwoven fabric constituting the nonwoven fabric sheet 25 of the embodiment include, but are not limited to, organic fibers such as polyester fibers, aliphatic polyamide fibers (nylon fibers), aromatic polyamide fibers (aramid fibers), polyvinyl alcohol-based fibers, and carbon fibers, and inorganic fibers such as metal fibers and glass fibers. From the viewpoint of weight reduction, nonwoven fabric made of organic fibers is preferable, and among organic fibers, polyester fibers are preferable from the viewpoints of cost reduction and strength.

[0047] The sheet-like nonwoven fabric is produced by a conventionally known production method. For example, methods for forming fibers into a sheet include a dry method, a wet method, a spunbond method, a meltblowing method, an airlaid method, etc., and methods for bonding fibers include, but are not limited to, a chemical bond method, a thermal bond method, a needle punch method, a hydroentanglement method, etc.

[0048] The type of rubber constituting the nonwoven fabric sheet 25 of the embodiment is not limited, but is preferably rubber used in tires, and in particular, if the rubber is the same type as the sidewall rubber 21, it has a high affinity with the sidewall rubber 21 and is preferable in that, for example, the nonwoven fabric sheet 25 is less likely to peel off from the sidewall rubber 21. Alternatively, rubber having a higher hardness than the sidewall rubber 21 is preferable because it improves resistance to external damage.

[0049] During the manufacture of tire 1, when tire 1 is in the state of a raw tire before vulcanization, the nonwoven fabric sheet 25 can be incorporated as part of the sidewall 20 by vulcanizing the entire tire 1 in a state in which the rubber adhering to the nonwoven fabric is also in the state of raw rubber before vulcanization and accommodated in the recess 22 of the sidewall rubber 21. Alternatively, the nonwoven fabric sheet 25 can be incorporated as part of the sidewall 20 by previously preparing a vulcanized nonwoven fabric sheet 25 by vulcanizing the rubber adhering to the nonwoven fabric, and then accommodating the nonwoven fabric sheet 25 in the recess 22 of the sidewall rubber 21 of the vulcanized tire and affixing it with an adhesive material.

[0050] The nonwoven fabric sheet 25 has the above-mentioned thickness when incorporated into the tire 1 as a part of the sidewall 20, i.e., when the rubber is vulcanized. The nonwoven fabric sheet 25 before vulcanization has a thickness of, for example, about 7 mm, but is compressed by the pressure during vulcanization to a thickness of 3 mm or more. This increases the density of the fibers in the thickness direction, increasing the strength and providing high resistance to external damage.

[0051] The nonwoven fabric sheet 25 according to the embodiment has the following positional relationship with other surrounding members.

[0052] An inner end 25a of the nonwoven fabric sheet 25 in the tire radial direction is disposed at a position that substantially coincides with the rim line 15c in the tire radial direction.

[0053] An inner end 25a of the nonwoven fabric sheet 25 in the tire radial direction is located more inward in the tire radial direction than an outer end 12a of the bead filler 12 in the tire radial direction.

[0054] In the tire radial direction, a tip 25b on the outer side in the tire radial direction of the nonwoven fabric sheet 25 is disposed so as to substantially coincide with a tip 35b on the inner side in the tire radial direction of the tread rubber 35 in the tire radial direction.

[0055] An outer end 25b of the nonwoven fabric sheet 25 in the radial direction of the tire is located more inward in the radial direction of the tire than an outer end 31a of the belt 31 in the axial direction of the tire.

[0056] 1, when the tire cross-sectional height from the tip on the inner side in the tire radial direction to the tip on the outer side in the tire radial direction is H, the tire radial direction region of nonwoven fabric sheet 25 is disposed, for example, within a range H3 between a position H1 that is 20% of the tire cross-sectional height H from the tip on the inner side in the tire radial direction and a position H2 that is 75%. This ensures that the proportion of nonwoven fabric sheet 25 in sidewall 20 is sufficiently large, and external damage resistance of sidewall 20 is ensured.

[0057] The above is the configuration of the tire 1 according to the embodiment. According to this tire 1, the surface layer of the sidewall 20 is formed by the nonwoven fabric sheet 25 instead of the sidewall rubber 21. Since the nonwoven fabric constituting the nonwoven fabric sheet 25 has high strength, the external damage resistance of the sidewall 20 is improved compared to the case where the nonwoven fabric sheet 25 is not provided. For example, when the sidewall 20 collides with a curb, in the embodiment, in most cases, the nonwoven fabric sheet 25 collides with the curb and is damaged. This is because the nonwoven fabric sheet 25 forms the outer surface 20c of the sidewall 20 and includes the tire maximum width position 20W of the sidewall 20. When the sidewall 20 collides with a curb, the external damage received is kept minor by the nonwoven fabric sheet 25, which has a higher external damage resistance than the sidewall rubber 21. Therefore, the external damage is less likely to reach the carcass ply 50, and the carcass ply 50 is prevented from being cut.

[0058] If the damage sustained by the nonwoven fabric sheet 25 is severe, it may cause a problem in appearance or may cause the sidewall 20 to not fully function. In such a case, the tire 1 of the embodiment may be repaired by replacing the nonwoven fabric sheet 25 with a new one. Examples of the repair method include the following method.

[0059] First, a removal process is performed to remove the existing nonwoven fabric sheet 25 that needs to be replaced from the sidewall 20. Both ends in the tire radial direction of the recess 22 in which the nonwoven fabric sheet 25 is housed are formed into a gently curved R-shape, making it easy to remove the nonwoven fabric sheet 25. Next, an arrangement process is performed to arrange a new nonwoven fabric sheet 25 in the recess 22 on the surface of the sidewall rubber 21 exposed after the nonwoven fabric sheet 25 has been removed.

[0060] Here, the arrangement process includes a preparation process of preparing a nonwoven fabric sheet 25 in which the rubber attached to the nonwoven fabric is in an unvulcanized state as a new nonwoven fabric sheet, a process of accommodating and attaching the new nonwoven fabric sheet 25 in the recess 22 of the sidewall rubber 21, and a vulcanization process of vulcanizing the unvulcanized rubber of the new nonwoven fabric sheet 25. The nonwoven fabric sheet 25 is adhered to the sidewall rubber 21 during vulcanization by the rubber attached to the nonwoven fabric.

[0061] The above-mentioned arrangement step may also involve preparing a nonwoven fabric sheet 25 in which the rubber to be attached to the nonwoven fabric has already been vulcanized as a new nonwoven fabric sheet, and placing the nonwoven fabric sheet 25 in the recess 22 on the surface of the sidewall rubber 21 and attaching it via an adhesive material. In this case, the adhesive material is preferably a vulcanization adhesive from the viewpoint of high adhesiveness to the sidewall rubber 21. The vulcanization adhesive may be a rubber component mixed with a vulcanization accelerator and an acid acceptor, and may be, for example, a composition of a polymeric material, an organic material, and a filler dispersed in an organic solvent such as xylene. As the polymeric material and the organic material, a halogen-based polymer or the like is used. As the filler, carbon black, silica, or the like is used.

[0062] The tire 1 according to the embodiment described above provides the following advantages.

[0063] (1) A tire 1 according to an embodiment includes a pair of beads 10 including a bead core 11 and a bead filler 12 extending radially outward from the bead core 11, a sidewall 20 extending radially outward from the pair of beads 10, including a sidewall rubber 21, and including a maximum width position 20W of the tire 1, a tread 30 disposed between the pair of sidewalls 20 and including a tread rubber 35, and a carcass ply 50 bridged between the pair of beads 10 and embedded inside the tire, and disposed axially inward of the sidewall rubber 21 in the sidewall 20, the sidewall 20 being disposed axially outward of the sidewall rubber 21, and including a nonwoven fabric sheet 25 having a nonwoven fabric and rubber attached to the nonwoven fabric, the nonwoven fabric sheet 25 being disposed so as to include the maximum width position 20W of the tire and form an outer surface 20c of the sidewall 20.

[0064] This improves the damage resistance of the sidewall 20, and even if the sidewall 20 is damaged, the carcass ply 50 is prevented from being cut, thereby extending the tire life. The nonwoven fabric sheet 25 is lighter than a rubber reinforcing member made of, for example, a cord and a topping rubber. Therefore, it is possible to obtain damage resistance while being lightweight, and to reduce rolling resistance. If the nonwoven fabric sheet 25 is damaged, it can be replaced with a new nonwoven fabric sheet 25. This makes it possible to avoid discarding the tire 1 even if the nonwoven fabric sheet 25 is damaged, and the tire life can be extended. Being able to discard the tire 1 and extending the tire life is economically and environmentally preferable.

[0065] (2) In the tire 1 of the above embodiment (1), the bead 10 further includes a rim protector 14 having a rim line 15c, and it is preferable that the radially inner tip 25a of the nonwoven fabric sheet 25 approximately coincides with the radial position of the rim line 15c.

[0066] As a result, when the tire 1 is mounted on the rim, the nonwoven fabric sheet 25 and the rim are disposed continuously with no gap therebetween, thereby ensuring resistance to external damage in the region extending from the rim to the nonwoven fabric sheet 25.

[0067] (3) In the above-described tire 1 according to the embodiments (1) and (2), it is preferable that the radially inner tip 25a of the nonwoven fabric sheet 25 is located radially inward of the radially outer tip 12a of the bead filler 12.

[0068] As a result, a portion of the nonwoven fabric sheet 25 and a portion of the bead filler 12 overlap in the tire radial direction, improving the external damage resistance of the sidewall 20.

[0069] (4) In the tire 1 according to the above embodiments (1) to (3), it is preferable that the radially outer end 25b of the nonwoven fabric sheet 25 is approximately aligned in the tire radial direction with the radially inner end 35b of the tread rubber 35, or is positioned radially outward in the tire radial direction of the inner end 35b of the tread rubber 35.

[0070] As a result, the nonwoven fabric sheet 25 and the tread rubber 35 are disposed continuously with no space therebetween, ensuring resistance to external damage in the region extending from the tread 30 to the nonwoven fabric sheet 25.

[0071] (5) In the tire 1 according to the above embodiments (1) to (4), the tread 30 includes a belt 31 arranged radially outward of the carcass ply 50, and it is preferable that the radially outer end 25b of the nonwoven fabric sheet 25 is positioned radially inward of the axially outer end 31a of the belt 31.

[0072] This ensures that the nonwoven fabric sheet 25 has resistance to external damage while preventing the nonwoven fabric sheet 25 from becoming excessively long in the tire radial direction.

[0073] (6) In the tire 1 according to the above embodiments (1) to (5), the nonwoven fabric sheet 25 preferably has a thickness of 3 mm or more and 9 mm or less.

[0074] This ensures that the nonwoven fabric sheet 25 is resistant to external damage while minimizing any increase in mass.

[0075] (7) The repair method for tire 1 according to the embodiment includes a removal step of removing nonwoven fabric sheet 25, and a placement step of placing a new nonwoven fabric sheet 25 on the surface of sidewall rubber 21 exposed after nonwoven fabric sheet 25 has been removed. The placement step includes a preparation step of preparing, as new nonwoven fabric sheet 25, a nonwoven fabric sheet in which the rubber adhering to the nonwoven fabric is in an unvulcanized state, a step of attaching new nonwoven fabric sheet 25 to the surface of sidewall rubber 21, and a vulcanization step of vulcanizing the unvulcanized rubber of the new nonwoven fabric sheet 25.

[0076] As a result, if the nonwoven fabric sheet 25 is damaged, it can be replaced with a new nonwoven fabric sheet 25, which makes it possible to avoid discarding the tire 1 and extend the tire life, which is therefore economically and environmentally preferable.

[0077] (8) The repair method for tire 1 according to the embodiment includes a removal step of removing nonwoven fabric sheet 25, and a placement step of placing a new nonwoven fabric sheet 25 on the surface of sidewall rubber 21 exposed after nonwoven fabric sheet 25 has been removed. The placement step includes a preparation step of attaching vulcanized rubber to the nonwoven fabric to prepare new nonwoven fabric sheet 25, and an attachment step of attaching the new nonwoven fabric sheet 25 to the surface of sidewall rubber 21 via an adhesive material.

[0078] As a result, if the nonwoven fabric sheet 25 is damaged, it can be replaced with a new nonwoven fabric sheet 25, which makes it possible to avoid discarding the tire 1 and extend the tire life, which is therefore economically and environmentally preferable.

[0079] (9) In the repair method according to embodiment (8) above, the adhesive material is preferably a vulcanizing adhesive.

[0080] This allows the newly provided nonwoven fabric sheet 25 to be attached to the sidewall rubber 21 of the tire 1 with high adhesive strength.

[0081] Fig. 2 shows a modified example of the tire 1 of the above embodiment. This modified example differs from the above embodiment mainly in the configuration of the overlapping portion between the sidewall rubber 21 and the tread rubber 35. In Fig. 2, the same components as those in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0082] 2, in contrast to the above embodiment, an end 21b on the outer side in the tire radial direction of the sidewall rubber 21 covers an end 35a on the outer side in the tire axial direction of the tread rubber 35. A buttress 70 including grooves 71 and protrusions 72 along the tire circumferential direction is formed on the outer surface of the end 21b on the outer side in the tire radial direction of the sidewall rubber 21.

[0083] In this modification, the tip 25b on the outer side in the tire radial direction of the nonwoven fabric sheet 25 is located slightly outward in the tire radial direction than the tip 35b on the inner side in the tire radial direction of the tread rubber 35. In this way, the outer end in the tire radial direction of the nonwoven fabric sheet 25 and the inner end in the tire radial direction of the tread rubber 35 overlap when viewed in the tire axial direction, so that the nonwoven fabric sheet 25 and the tread rubber 35 are continuous in the tire radial direction. This makes it difficult for distortion to occur in the region extending from the sidewall 20 to the tread 30, improving rigidity.

[0084] In this modified example, the effects of the nonwoven fabric sheet 25 can be obtained in the same manner as in the above embodiment.

[0085] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and even if modifications and improvements are made within the scope of the present invention, they will still be included in the scope of the present invention. [Explanation of symbols]

[0086] 1...Tire (pneumatic tire) 10...Bead 11...Bead core 12...Bead filler 12a…Tire radial outer tip of bead filler 14…Rim protector 20…Sidewall 20c…Outer surface of sidewall 20W…Tire maximum width position 21c…Rimline 25…Nonwoven sheet 25a…Tire radially inner tip of nonwoven fabric sheet 25b…Tire radially outer tip of nonwoven fabric sheet 25c…Outer surface of nonwoven fabric sheet 30…Tread 31...Belt 31a…Tire axial outer end of belt 35...Tread rubber 35b…Tire radially inner tip of tread rubber 50…Carcass ply

Claims

1. A pair of beads including a bead core and a bead filler extending from the bead core outward in a radial direction of the tire; a sidewall extending radially outward from the pair of beads, the sidewall including a sidewall rubber and including a maximum tire width position; a tread including a tread rubber, the tread being disposed between the pair of sidewalls; a carcass ply that is bridged between a pair of the beads and embedded inside the tire, and that is disposed axially inward of the sidewall rubber in the sidewall, The sidewall is A nonwoven fabric sheet is disposed on the outer side of the sidewall rubber in the tire axial direction, and has a nonwoven fabric and a rubber attached to the nonwoven fabric, The nonwoven fabric sheet is arranged to form an outer surface of the sidewall so as to include the maximum width position of the tire.

2. The bead further includes a rim protector having a rim line; The pneumatic tire according to claim 1 , wherein a tip end of the nonwoven fabric sheet on an inner side in a radial direction of the tire substantially coincides with a position of the rim line in a radial direction of the tire.

3. The pneumatic tire according to claim 1 , wherein an inner end of the nonwoven fabric sheet in the tire radial direction is located more inward in the tire radial direction than an outer end of the bead filler in the tire radial direction.

4. 3. The pneumatic tire according to claim 1, wherein a radially outer end of the nonwoven fabric sheet is aligned in the tire radial direction with a radially inner end of the tread rubber, or is aligned in the tire radial direction outward of a radially inner end of the tread rubber.

5. The tread includes a belt disposed on an outer side of the carcass ply in a tire radial direction, The pneumatic tire according to claim 1 , wherein an outer end of the nonwoven fabric sheet in the tire radial direction is located more inward in the tire radial direction than an outer end of the belt in the tire axial direction.

6. The pneumatic tire according to claim 1 or 2, wherein the nonwoven fabric sheet has a thickness of 3 mm or more and 9 mm or less.

7. 10. A method for repairing a pneumatic tire as claimed in claim 1, comprising the steps of: a removing step of removing the nonwoven fabric sheet; and a placement step of placing a new nonwoven fabric sheet on the surface of the sidewall rubber exposed after the nonwoven fabric sheet is removed, The placing step includes: a preparation step of preparing a nonwoven fabric sheet in which the rubber to be adhered to the nonwoven fabric is in an unvulcanized state as the new nonwoven fabric sheet; attaching the new nonwoven fabric sheet to a surface of the sidewall rubber; and a vulcanization step of vulcanizing the unvulcanized rubber of the new nonwoven fabric sheet.

8. 10. A method for repairing a pneumatic tire as claimed in claim 1, comprising the steps of: a removing step of removing the nonwoven fabric sheet; and a placement step of placing a new nonwoven fabric sheet on the surface of the sidewall rubber exposed after the nonwoven fabric sheet is removed, The placing step includes: a preparation step of attaching the vulcanized rubber to the nonwoven fabric to prepare the new nonwoven fabric sheet; and a bonding step of bonding the new nonwoven fabric sheet to the surface of the sidewall rubber via an adhesive material.

9. 9. The method of repairing a pneumatic tire of claim 8, wherein the adhesive material is a vulcanizing adhesive.

Images