JP2015147474A - run-flat radial tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a run-flat radial tire which inhibits the occurrence of a buckling phenomenon in a tire side part during run-flat driving.SOLUTION: A run-flat radial tire 10 includes: a carcass 14 spanning between a pair of bead parts 12; side reinforcement layers 24, each of which is provided at a tire side part 22 connecting the bead part 12 with a tread part 20; and outer reinforcement cord layers 34, each of which is provided at the outer side of the tire side part 22 relative to the carcass 14 in a tire width direction and includes a metal cord inclining relative to a tire circumferential direction.

Description

  The present invention relates to a run-flat radial tire.

  As a run-flat tire that can travel a certain distance even when the tire is punctured and the internal pressure is reduced, there is a side-reinforced run-flat radial tire in which a tire side portion is reinforced with a side reinforcing rubber (side reinforcing layer) (for example, , See Patent Document 1).

JP 2012-116212 A

  By the way, with side-reinforced run-flat radial tires, when the slip angle is input, for example, when the vehicle turns while running with a reduced internal pressure (run-flat running), the load of the side reinforcing rubber is supported. A part may change, the vertical load of a tire may increase, and the buckling phenomenon that a tire side part may bend | fold inside a tire may generate | occur | produce.

  In consideration of the above facts, an object of the present invention is to provide a run-flat radial tire that can suppress occurrence of a buckling phenomenon at a tire side portion during run-flat traveling.

  The run-flat radial tire according to the first aspect of the present invention includes a carcass straddling between a pair of bead portions, a side reinforcing layer provided on a tire side portion connecting the bead portion and the tread portion, and the tire. An outer reinforcing cord layer provided with a metal cord which is provided on the outer side in the tire width direction from the carcass of the side portion and is inclined with respect to the tire circumferential direction.

  According to the run flat radial tire according to the first aspect of the present invention, the side reinforcing layer is provided on the tire side portion connecting the bead portion and the tread portion. An outer reinforcing cord layer having a metal cord inclined with respect to the tire circumferential direction is provided on the outer side in the tire width direction from the carcass of the tire side portion. As a result, the compression rigidity of the tire side portion is increased, and even when the vertical load of the tire increases due to the addition of a slip angle, the amount of bending that the tire side portion bends inside the tire is reduced, and the buckling phenomenon is reduced. Occurrence can be suppressed.

  A run-flat radial tire according to a second aspect of the present invention is the run-flat radial tire according to the first aspect, wherein the carcass includes a folded portion that is folded from the tire inner side to the outer side and extends to the tread portion around the bead core of the bead portion. The outer reinforcing cord layer is disposed on the outer side in the tire width direction of the folded portion.

  According to the run-flat radial tire according to the second aspect of the present invention, the compression rigidity of the tire side portion is further increased and the occurrence of the buckling phenomenon is suppressed as compared with the configuration in which the carcass does not include the folded portion. can do.

  A run-flat radial tire according to a third aspect of the present invention is the run-flat radial tire according to the first or second aspect, wherein an inner reinforcing cord layer that is inclined with respect to the tire circumferential direction is provided on the inner side in the tire width direction from the carcass of the tire side portion. I have.

  According to the run flat radial tire according to the third aspect of the present invention, by providing the inner reinforcing cord layer, the neutral surface when the tire side portion is bent is shifted to the tire inner surface side, and the buckling phenomenon occurs. It is possible to increase the suppression effect. That is, when the neutral surface of bending when the inner reinforcing cord layer is not provided is set in the vicinity of the carcass, the neutral surface is shifted to the tire inner surface side by providing the inner reinforcing cord layer. As a result, the distance between the outer reinforcing cord layer and the neutral surface is widened, and the effect of compression rigidity by the outer reinforcing cord layer can be effectively exhibited.

  The run-flat radial tire according to a fourth aspect of the present invention is the run-flat radial tire according to the third aspect, wherein the inner reinforcing cord layer is an organic fiber cord layer including a mechanical fiber cord.

  According to the run-flat radial tire of the present invention as set forth in claim 4, by using an organic fiber cord having a compression rigidity lower than that of the metal cord, the tire side portion is prevented from becoming too hard and the riding comfort is good. Can be maintained.

  Since the present invention is configured as described above, it is possible to suppress the occurrence of the buckling phenomenon of the tire side portion during run-flat traveling.

1 is a half sectional view showing one side of a cut surface obtained by cutting a run-flat radial tire according to a first embodiment of the present invention along a tire axial direction. It is sectional drawing cut | disconnected along the tire axial direction which shows the state at the time of the run flat running of the run flat radial tire which concerns on 1st Embodiment of this invention. It is a half sectional view showing one side of a cut surface which cut a run flat radial tire concerning a 2nd embodiment of the present invention along a tire axial direction. It is the side view which looked at the run flat radial tire of the comparative example at the time of run flat running from the tire axial direction. It is a graph which shows the relationship between the rim | limb removal parameter | index inside a turning of a tire, and the rim | limb removal parameter | index outside a turning.

<First Embodiment>
(Configuration of run-flat radial tire)
Hereinafter, a run-flat radial tire 10 (hereinafter referred to as “tire 10”) according to an embodiment of the present invention will be described with reference to the drawings. In the drawing, the arrow TW indicates the width direction (tire width direction) of the tire 10, and the arrow TR indicates the radial direction (tire radial direction) of the tire 10. The tire width direction here refers to a direction parallel to the rotation axis of the tire 10 and is also referred to as a tire axial direction. The tire radial direction refers to a direction orthogonal to the rotation axis of the tire 10. Reference sign CL indicates the equator plane of the tire 10 (tire equator plane). Further, in the present embodiment, the rotation axis side of the tire 10 along the tire radial direction is “inner side in the tire radial direction”, and the opposite side of the tire 10 along the tire radial direction is “outer side in the tire radial direction”. It describes. On the other hand, the equatorial plane CL side of the tire 10 along the tire width direction is referred to as “inner side in the tire width direction”, and the side opposite to the equatorial plane CL along the tire width direction is referred to as “outer side in the tire width direction”.

  In FIG. 1, the tire 10 is shown when mounted on a standard rim 30 (indicated by a two-dot chain line in FIG. 1) and filled with standard air pressure. Here, the standard rim is a rim defined in the Year Book 2013 version of JATMA (Japan Automobile Tire Association). The standard air pressure is the air pressure corresponding to the maximum load capacity of the Year Book 2013 version of JATMA (Japan Automobile Tire Association).

  In the following description, the load is the maximum load (maximum load capacity) of a single wheel at the applicable size described in the following standard, and the internal pressure is the single wheel described in the following standard. It is the air pressure corresponding to the maximum load (maximum load capacity), and the rim is a standard rim (or “Applied Rim” or “Recommended Rim”) in an application size described in the following standard. The standards are determined by industry standards that are valid in the region where the tire is produced or used. For example, in the United States, “The Tire and Rim Association Inc. Year Book”, in Europe “The European Tire and Rim Technical Standards Standards” in the Japan Automobile Association of Japan Has been.

  As shown in FIG. 1, the tire 10 according to the present embodiment mainly includes a pair of bead parts 12, a carcass 14, an inclined belt layer 16, a cap layer 17, a reinforcing cord layer 18, and a tread part. 20, a tire side portion 22, a side reinforcing rubber 24 as a side reinforcing layer, and a metal cord layer 34 as an outer reinforcing cord layer. Here, when the tire 10 is assembled to the standard rim 30 and the internal pressure is set to the standard air pressure, a length that is ½ of the difference between the tire outer diameter and the rim diameter is the tire cross-section height SH (section height SH). The tire 10 in FIG. 1 has a tire cross-section height SH set to 115 mm or more. In the present embodiment, as an example, the tire cross-section height SH is 129 mm. However, the present invention is not limited thereto, and a tire having a tire cross-section height SH lower than 115 mm may be used.

  A pair of left and right bead portions 12 are provided at intervals in the tire width direction (in FIG. 1, only one bead portion 12 is shown). A bead core 26 is embedded in each of the pair of bead portions 12, and the carcass 14 straddles between the bead cores 26.

  The carcass 14 is constituted by one or a plurality of carcass plies, and the carcass ply is formed by coating a plurality of cords (for example, an organic fiber cord or a metal cord) with a covering rubber. In addition, the carcass 14 extends from one bead core 26 to the other bead core 26 in a toroidal shape and forms a tire skeleton, and a carcass main body 14A is formed around the bead core 26 from one end and the other end of the carcass main body 14A. And a folded portion 14B that is folded from the tire inner side to the outer side and extends to a tread portion 20 described later. In the present embodiment, the turn-up portion 14B is provided in the carcass 14. However, the present invention is not limited to this. For example, a plurality of bead core pieces are arranged in the bead portion 12, and the carcass 14 is sandwiched between the plurality of bead core pieces. It is good also as a structure.

  A bead filler 28 extending from the bead core 26 to the outer side in the tire radial direction is embedded in a region sandwiched between the carcass main body portion 14A and the folded portion 14B of the bead portion 12. The bead filler 28 has an end portion 28A on the outer side in the tire radial direction entering the tire side portion 22, and the thickness decreases toward the outer side in the tire radial direction.

  An inclined belt layer 16 is disposed outside the carcass 14 in the tire radial direction. The inclined belt layer 16 is constituted by one or a plurality of belt plies 16A. In the present embodiment, the inclined belt layer 16 is constituted by two belt plies 16A as an example. The belt ply 16A is formed by coating a plurality of cords (for example, an organic fiber cord or a metal cord) with a covering rubber. The cords constituting the belt ply 16A are disposed at an inclination angle of 15 to 30 degrees with respect to the tire circumferential direction. In the present embodiment, as an example, the cords are provided at an inclination angle of 26 degrees. ing. The inclined belt layer 16 is formed from one end portion of the tread portion 20 in the tire width direction to the other end portion.

  A cap layer 17 is disposed outside the inclined belt layer 16 in the tire radial direction. The cap layer 17 covers the entire inclined belt layer 16, and a reinforcing cord layer 18 is disposed on the outer side of the cap layer 17 in the tire radial direction. In the present embodiment, as an example, the reinforcing cord layers 18 are formed at both ends of the tread portion 20 (in FIG. 1, only one reinforcing cord layer 18 is illustrated). The reinforcing cord layer 18 may be formed from one end portion to the other end portion of the tread portion 20 in the tire width direction. Further, the reinforcing cord layer 18 may be formed from one end portion of the tread portion 20 in the tire width direction to the other end portion, and the reinforcing cord layer 18 may be separately formed only on the shoulder portion. Furthermore, the reinforcing cord layer 18 may not be provided.

  The reinforcing cord layer 18 is formed so that a plurality of cords are inclined at an inclination angle of 60 degrees to 90 degrees with respect to the tire circumferential direction. In this embodiment, as an example, the reinforcement cord layer 18 is inclined at an inclination angle of 90 degrees. It is arranged to do. Further, as the cord constituting the reinforcing cord layer 18, an organic fiber cord or a metal cord is used. In this embodiment, PET is used as an example.

  A tread portion 20 is provided on the outer side in the tire radial direction of the inclined belt layer 16 and the cap layer 17. The tread portion 20 is a portion that contacts the road surface during traveling, and a circumferential groove 20A extending in the tire circumferential direction is formed on the surface of the tread portion 20. Further, the tread portion 20 is formed with a not-shown width direction groove extending in the tire width direction. In addition, the shape and number of the circumferential grooves 20A and the width direction grooves are appropriately set according to performances such as drainage performance and steering stability required for the tire 10.

  A tire side portion 22 is provided between the bead portion 12 and the tread portion 20. The tire side portion 22 extends in the tire radial direction and connects the bead portion 12 and the tread portion 20 and is configured to be able to bear a load acting on the tire 10 during run-flat travel.

  Here, a side reinforcing rubber 24 that reinforces the tire side portion 22 is disposed on the tire side portion 22 on the inner side in the tire width direction of the carcass 14. The side reinforcing rubber 24 is a reinforcing rubber for traveling a predetermined distance while supporting the weight of the vehicle and the occupant when the internal pressure of the tire 10 decreases due to puncture or the like. In this embodiment, the side reinforcing rubber mainly composed of rubber is disposed as an example. However, the present invention is not limited to this, and may be formed of other materials, for example, thermoplastic resin or the like as a main component. It may be formed.

  In the present embodiment, the side reinforcing rubber 24 is formed of one type of rubber member. However, the present invention is not limited to this, and the side reinforcing rubber 24 may be formed of a plurality of rubber members. Further, the side reinforcing rubber 24 may include other materials such as fillers, short fibers, and resins as long as the rubber member is a main component. Furthermore, in order to increase the durability during run-flat running, the rubber member constituting the side reinforcing rubber 24 may include a rubber member having a JIS hardness of 70 to 85 measured at 20 ° C. using a durometer hardness tester. . Furthermore, the loss coefficient tan δ measured by using a viscoelastic spectrometer (for example, a spectrometer manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a frequency of 20 Hz, an initial strain of 10%, a dynamic strain of ± 2%, and a temperature of 60 ° C. is 0.10 or less. A rubber member having physical properties may be included.

  The side reinforcing rubber 24 extends in the tire radial direction along the inner surface of the carcass 14 and has a shape that decreases in thickness toward the bead core 26 side and the tread portion 20 side, for example, a substantially crescent shape. The end portion 24A on the inner side in the tire radial direction of the side reinforcing rubber 24 extends to the inner side in the tire width direction of the bead filler 28, and the end portion 24B on the outer side in the tire radial direction of the side reinforcing rubber 24 is the tread portion 20. Has been extended to. Here, the thickness refers to the length of a straight line drawn to the carcass 14 perpendicular to the side reinforcing rubber 24 in a state where the tire 10 is assembled to the standard rim 30 and the internal pressure is standard air pressure. The side reinforcing rubber 24 may be connected at the tire equator plane.

  An inner liner 32 is disposed on the inner surface of the side reinforcing rubber 24 from one bead portion 12 to the other bead portion 12. In the present embodiment, as an example, the inner liner 32 containing butyl rubber as a main component is disposed. However, the present invention is not limited thereto, and other rubber members or resins may be used as a main component. In the present embodiment, one layer of the side reinforcing rubber 24 is sandwiched between the inner liner 32 and the carcass 14. However, the present invention is not limited to this. For example, a separate carcass is provided between the inner liner 32 and the carcass 14. It is good also as a structure which arrange | positions and the side reinforcement rubber 24 was parted.

  Here, a metal cord layer 34 as an outer reinforcing cord layer is disposed on the outer side in the tire radial direction of the folded portion 14B of the carcass 14. The metal cord layer 34 is formed so that a plurality of metal cords are inclined at an inclination angle of 60 to 90 degrees with respect to the tire circumferential direction. In the present embodiment, as an example, the metal cord layer 34 is inclined at an inclination angle of 90 degrees. It arrange | positions so that it may incline. Moreover, as a metal cord which comprises the metal cord layer 34, in this embodiment, although the steel cord is used as an example, not only this but another metal cord may be used.

  Further, the end 34 </ b> A on the inner side in the tire radial direction of the metal cord layer 34 extends between the end 24 </ b> A on the inner side in the tire radial direction of the side reinforcing rubber 24 and the bead core 26. Further, the end 34 </ b> B on the outer side in the tire radial direction of the metal cord layer 34 extends to a region between the tire side portion 22 and the tread portion 20. The length of the metal cord layer 34 is not limited to this, and may be changed as appropriate according to the size of the tire 10 and the required weight. For example, the end 34 </ b> B on the outer side in the tire radial direction of the metal cord layer 34 may be extended to a position where it overlaps with the inclined belt layer 16 and the cap layer 17.

  In this embodiment, since the tire 10 having a high section height SH is targeted, the rim guard (rim protection) is not provided. However, the present invention is not limited thereto, and a rim guard may be provided.

(Function and effect)
Next, the operation of the tire 10 of the present embodiment will be described through description of the buckling phenomenon that occurs in the tire side portion inside the turning of the vehicle. In the following description, a tire 100 shown in FIG. 4 is obtained by mounting a comparative tire 100 that does not have the reinforcing cord layer 18 according to the present embodiment on a standard rim 30.

  As shown in FIG. 4, during the run-flat running, the ground contact portion of the tire 100 is greatly bent, and in this state, for example, when a slip angle is input by cornering, the ground contact portion of the tire 100 is crushed. As the deflection of the tire 100 increases and the deflection propagates to the front side in the traveling direction of the tire 100, the belt diameter of the stepping side portion F increases (note that the arrow in FIG. 4 indicates the tire rotation direction). ). As a result, the tensile force on the outer side in the tire radial direction with respect to the bead portion is increased. On the other hand, when the load supporting portion of the side reinforcing rubber is changed, the vertical load of the tire is increased, and a buckling phenomenon in which the tire side portion 102 is bent inside the tire may occur. In addition, a phenomenon in which the bead portion is detached from the standard rim 30 (rim removal) may occur due to the expansion of the belt diameter and the buckling phenomenon.

  Incidentally, as shown in FIG. 5, it has been confirmed that the buckling phenomenon is likely to occur in a tire having a section height SH of 115 mm or more. The graph shown in FIG. 5 is obtained by examining the rim detachment index with respect to the section height SH using a run-flat radial tire with the tire width changed to 215 mm and the tire cross-section height SH changed, and the numerical value of the rim detachment index is large. It shows that it is hard to come off the rim. According to the graph of FIG. 5, in the run flat radial tire having a tire cross-section height of 115 mm or more, the rim detachment index on the tire turning inner side is small, and the rim is easily detached. That is, it has been confirmed that the buckling phenomenon is likely to occur. The upper limit of the height of the section height SH is not particularly limited, but is, for example, 155 mm or less.

  Here, in the tire 10 according to the present embodiment, as shown in FIG. 1, a metal cord provided with a metal cord inclined toward the tire circumferential direction on the outer side in the tire width direction from the carcass 14 of the tire side portion 22. A layer 34 is provided. As a result, the compression rigidity of the tire side portion 22 is increased, and even when the load supporting portion of the side reinforcing rubber is changed and the vertical load of the tire is increased, the amount of bending at which the tire side portion 22 bends inside the tire is reduced. Thus, the occurrence of the buckling phenomenon can be suppressed.

  Further, since the metal cord layer 34 is formed of a metal cord inclined at an inclination angle of 60 degrees to 90 degrees with respect to the tire circumferential direction, the metal cord layer 34 increases the bending rigidity of the tire shoulder portion, and the buckling The occurrence of the phenomenon is suppressed. As a result, it is possible to prevent the bead portion 12 from being detached from the standard rim 30.

  Further, in the present embodiment, a folded portion 14B is provided that is folded around the bead core 26 from the one end portion and the other end portion of the carcass main body portion 14A to the tire outer side. Thereby, compared with the structure in which the carcass 14 is not provided with the folding | turning part 14B, the compression rigidity of the tire side part 22 can be improved more, and generation | occurrence | production of a buckling phenomenon can be suppressed.

  In the present embodiment, the reinforcing cord layers 18 are provided at both ends of the tread portion 20. However, the present invention is not limited to this, and for example, the reinforcing cord layer 18 is provided only at one end portion of the tread portion 20 located inside the turning of the tire 10. May be provided. A plurality of reinforcing cord layers 18 may be formed. In this case, the effect of suppressing rim detachment can be further enhanced.

Second Embodiment
Next, a run flat radial tire 50 (hereinafter referred to as “tire 50”) according to a second embodiment of the present invention will be described. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted suitably.

  As shown in FIG. 3, in the tire 50 of the present embodiment, an organic fiber cord layer 52 as an inner reinforcing cord layer is provided between the inner liner 32 and the side reinforcing rubber 24. The organic fiber cord layer 52 is disposed on the inner side in the tire width direction than the carcass 14 of the tire side portion 22 and is sandwiched between the side reinforcing rubber 24 and the inner liner 32. The organic fiber cord layer 52 is provided at a position corresponding to at least the midpoint between the end portion 28A of the bead filler 28 in the tire radial direction and the end portion 24A of the side reinforcing rubber 24 in the tire radial direction. .

  Furthermore, the organic fiber cord layer 52 is configured to include a plurality of organic fiber cords that are inclined at an inclination angle of 60 degrees to 90 degrees with respect to the tire circumferential direction. It is assumed that the inclination angle of degree. In this embodiment, PET is used as an example of the cord constituting the organic fiber cord layer 52. However, the present invention is not limited to this, and other organic fiber cords may be used. Further, the inner reinforcing cord layer may be formed using a metal cord such as a steel cord.

  An end portion 52A on the inner side in the tire radial direction of the organic fiber cord layer 52 extends from an end portion 24A on the inner side in the tire radial direction of the side reinforcing rubber 24 to the inner side in the tire radial direction. Further, the end portion 52B on the outer side in the tire radial direction of the organic fiber cord layer 52 extends from the end portion 24B on the outer side in the tire radial direction of the side reinforcing rubber 24 to the outer side in the tire radial direction.

  According to the tire 50 of the present embodiment, by providing the organic fiber cord layer 52, the neutral surface when the tire side portion 22 is bent is shifted to the tire inner surface side, and the effect of suppressing the buckling phenomenon is enhanced. Can do. That is, when the neutral surface of the bending in the configuration in which the organic fiber cord layer 52 is not provided is set in the vicinity of the carcass, the neutral surface is shifted to the tire inner surface side by providing the organic fiber cord layer 52. Can do. As a result, the distance between the metal cord layer 34 and the neutral surface is widened, and the effect of compression rigidity by the metal cord layer 34 can be effectively exhibited.

  Moreover, in this embodiment, since the organic fiber cord layer 52 is formed using an organic fiber cord having a compression rigidity lower than that of the metal cord, the tire side portion 22 is prevented from becoming too hard and the riding comfort is good. Can be maintained.

(Test example)
In order to confirm the effects of the run-flat radial tire according to the present invention, the following flat run radial tires of Examples 1 to 4 and the run-flat radial tire of Comparative Example 1 not included in the present invention were prepared, and the following tests were performed. Carried out.

  First, the run flat radial tires of Examples 1 to 4 and the run flat radial tire of Comparative Example 1 used in the test will be described. The sizes of the run-flat radial tires used in the test are all 215 / 60R17, and the run-flat radial tire of Example 1 adopts the same structure as that of the first embodiment. That is, there is provided a metal cord layer in which the steel cord is disposed at an inclination angle of 90 degrees with respect to the tire circumferential direction. The run-flat radial tires of Examples 2 to 4 adopt the same structure as that of the second embodiment. In addition to the metal cord layer, an inner reinforcement cord layer is provided between the side reinforcement rubber and the inner liner. Provided. The inner reinforcing cord layers are made of different materials.

  In the run-flat radial tire of Comparative Example 1, the metal cord layer is not provided on the outer side in the tire width direction of the carcass, and the inner reinforcing cord layer is not provided on the inner side in the tire radial direction of the carcass. Other configurations are the same as those in the first embodiment and the second embodiment.

  In the test, first, a test tire was assembled on a standard rim of JATMA standard, mounted on a vehicle without filling with air (with an internal pressure of 0 kPa), and conditioned for a distance of 5 km at a speed of 20 km / h. After that, entering a turning circuit having a radius of curvature of 25 m at a predetermined speed and stopping at a position of 1/3 turn of this turning circuit was performed twice in succession (J-turn test). When the bead portion did not come off the rim, the turning acceleration was increased and the operation was repeated. Here, with reference to the turning acceleration when the bead portion of Comparative Example 1 is removed from the rim as a reference value (100), the turning acceleration when each bead portion of Examples 1 to 4 is removed from the rim is shown in Table 1 Expressed as an index in the column of “Outlier Index”. The “rim removal index” is an index that represents the turning acceleration when the bead part is removed from the rim, and the larger the value, the better the result.

  As shown in Table 1, it was confirmed that Example 1 in which the metal cord layer was provided with respect to the tire of the comparative example gave a better result of the rim detachment index. This seems to be because the occurrence of the buckling phenomenon was suppressed.

  In addition, it was confirmed that the tires of Examples 2 to 4 provided with the inner reinforcing cord layer had better results on the rim detachment index than that of Example 1. Further, as the material of the inner reinforcing cord layer, PET is better than nylon, and steel has a better result. On the other hand, when the inner reinforcing cord layer is formed of a steel cord, the tire side portion 22 becomes too hard and may affect the ride comfort. In this case, by using an organic fiber cord such as nylon or PET that has a lower compression rigidity than steel, it is possible to maintain a good riding comfort while suppressing the occurrence of the buckling phenomenon.

  The first embodiment and the second embodiment of the present invention have been described above. However, the present invention is not limited to such an embodiment, and can be implemented in various modes without departing from the gist of the present invention. Of course.

10, 50: Run flat radial tire, 12: Bead portion, 14: Carcass, 14B: Turned portion, 20: Tread portion, 22: Tire side portion, 24: Side reinforcing rubber (side reinforcing layer), 34: Outer reinforcing cord Layer, 52: inner reinforcement cord layer

Claims (4)

A carcass straddling between a pair of bead parts;
A side reinforcing layer provided on a tire side portion connecting the bead portion and the tread portion;
An outer reinforcing cord layer provided with a metal cord provided on the outer side in the tire width direction from the carcass of the tire side portion and inclined with respect to the tire circumferential direction;
Run-flat radial tire having The carcass includes a folded portion that is folded from the tire inner side to the outer side and extends to the tread portion around the bead core of the bead portion,
The run-flat radial tire according to claim 1, wherein the outer reinforcing cord layer is disposed on the outer side in the tire width direction of the folded portion.   3. The run-flat radial tire according to claim 1, further comprising an inner reinforcing cord layer inclined with respect to a tire circumferential direction on an inner side in a tire width direction than the carcass of the tire side portion.   The run-flat radial tire according to claim 3, wherein the inner reinforcing cord layer is an organic fiber cord layer including an organic fiber cord.

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