Pneumatic tire

Abstract

To provide a tire capable of suppressing the temperature increase of the tire caused by an air temperature or direct sunlight and improving crack resistance and operation stability.SOLUTION: This pneumatic tire comprises a tread 1, a pair of side walls 2, and a pair of beads 3. Each of the beads 3 includes a bead core 5 and a bead filler 6. At least one carcass layer 4 is mounted between the beads 3. A high-reflection rubber layer 22 having light reflectance higher than that of a body rubber layer 21 constituting the other part of the side walls 2, the light reflectance being 70% or lower, is disposed on the outer surface of the side walls 2 corresponding to the tire-radial outside end of the bead filler 6 and / or the end of the carcass layer 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pneumatic tire including a portion made of rubber other than black on the outer surface of the sidewall portion.

Background Art

[0002] Generally, pneumatic tires are made of black rubber compounded with carbon black. Therefore, on a hot day, for example, the temperature of the tire tends to rise during parking due to direct sunlight. During high-speed driving, the temperature of the tire reaches an equilibrium state, but at the start of driving or during urban driving (a state where starting and stopping are repeated at short intervals), the temperature of the tire becomes high according to the air temperature and parking time. And the excessive rise in the temperature of the sidewall portion is a factor causing cracks at the ends of tire constituent members typified by bead fillers and carcass layers. Further, if the internal pressure of the tire rises excessively as the temperature of the tire rises, there is a risk that the handling stability deteriorates.

[0003] On the other hand, for example, a tire (see, for example, Patent Document 1) in which colored rubber (color rubber) is disposed on the outer surface of the sidewall portion for decorative purposes, or a tire (so-called white ribbon tire) in which white rubber (white rubber) is disposed on the outer surface of the sidewall portion is known. Since such a tire has a sidewall portion made of rubber other than black, it is presumed that the temperature rise and heat storage due to the above-mentioned air temperature and direct sunlight are suppressed as compared with a general tire having a sidewall portion made of black rubber. However, for example, white rubber suppresses the blackening of rubber mainly by using calcium carbonate, titanium oxide, etc. instead of carbon black as a filler, so sufficient rigidity cannot be ensured like general black rubber, which is a factor deteriorating the handling stability.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a tire capable of suppressing an increase in the temperature of the tire due to air temperature and direct sunlight and improving crack resistance and handling stability.

Means for Solving the Problems

[0006] In a pneumatic tire for achieving the above object, which includes a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the tire radial direction inner side of these sidewall portions, a bead core disposed in each of the bead portions, a bead filler disposed on the tire radial direction outer side of the bead core, and at least one carcass layer mounted between the pair of bead portions, a high-reflection rubber layer having a higher light reflectance than the rubber constituting the other portions of the sidewall portion and a light reflectance of 70% or less is provided on the outer surface of the sidewall portion corresponding to the tire radial direction outer end portion of the bead filler and / or the end portion of the carcass layer.

Effects of the Invention

[0007] In the pneumatic tire of the present invention, since the highly reflective rubber layer is locally disposed in a part of the sidewall portion as described above, it is possible to suppress the temperature rise of the tire due to the air temperature and direct sunlight, and to improve the crack resistance and handling stability. Specifically, since the highly reflective rubber layer is disposed so as to cover the member end portions of the bead filler and the carcass layer, the temperature rise of the sidewall portion is suppressed, and cracks at the member end portions caused by the temperature rise of the sidewall portion can be prevented (the crack resistance is improved). Further, since the rise in the tire temperature is suppressed, the rise in the tire internal pressure accompanying the rise in the tire temperature is also suppressed, so that the handling stability can be favorably exhibited. Furthermore, since the highly reflective rubber layer is locally disposed in a part of the sidewall portion as described above and the light reflectance is 70% or less (that is, it is not a white rubber having a significantly small amount of carbon black and low reinforcing performance), the rigidity of the sidewall portion can be sufficiently ensured, and the handling stability can also be favorably exhibited from this point.

[0008] In the present invention, the "light reflectance" is the ratio of the amount of light reflected by the sample (the rubber constituting the highly reflective rubber layer) to the amount of light directly measured from the light source (the so-called "absolute reflectance"), and is measured using an integrating sphere attachment device (manufactured by Shimadzu Corporation) for the diffuse reflected light and specular reflected light (total light reflected light) when the reflection surface is irradiated with light at an angle of 8 degrees with respect to the normal direction of the reflection surface of the sample.

[0009] In the present invention, it is preferable that the highly reflective rubber layer is disposed on the outer surface of the sidewall portion corresponding to the radially outer end portion of the bead filler and the end portion of the carcass layer in the tire diameter direction. In this way, it is advantageous for improving the crack resistance by disposing the highly reflective rubber layer so as to cover both of the member end portions (the end portions of the bead filler and the carcass layer) that can be the starting points of cracks caused by the temperature rise of the sidewall portion.

[0010] In the present invention, it is preferable that the light reflectance of the highly reflective rubber layer is 10% or more. Thereby, the highly reflective rubber layer can effectively reflect sunlight, which is advantageous for suppressing the temperature rise of the tire due to sunlight.

[0011] In the present invention, it is preferable that the tire diameter direction length W of the high-reflection rubber layer is 10% to 50% of the tire cross-sectional height SH. Thereby, the high-reflection rubber layer comes to cover an appropriate range in the sidewall portion, and while ensuring the rigidity of the sidewall portion, it is possible to suppress the rise in tire temperature and the accompanying rise in tire internal pressure, which is advantageous for improving crack resistance and handling stability.

[0012] In the present invention, it is preferable that the thickness of the high-reflection rubber layer is 1.0 mm or more and 3.0 mm or less. Thereby, it is possible to ensure the rigidity of the sidewall portion while ensuring appropriate light reflection performance, which is advantageous for improving crack resistance and handling stability.

[0013] In the present invention, it may also be configured to have a mounting direction display portion indicating the mounting direction with respect to the vehicle, the pair of sidewall portions being composed of an inner sidewall portion located on the inner side of the vehicle when mounted on the vehicle and an outer sidewall portion located on the outer side of the vehicle when mounted on the vehicle, and at least the outer sidewall portion being provided with a high-reflection rubber layer. In this configuration, since the temperature rise can be effectively suppressed in the outer sidewall portion where sunlight is likely to hit, it is advantageous for improving crack resistance and handling stability.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

[0016] The pneumatic tire of the present invention, as shown in FIGS. 1 and 2, includes a tread portion 1 that contacts the road surface, a pair of sidewall portions 2 disposed on both sides of the tread portion 1, and a pair of bead portions 3 disposed on the inner side in the tire diameter direction of the sidewall portions 2. In FIG. 1, the symbol CL indicates the tire equator. Although not depicted because FIG. 1 is a meridian half-sectional view, the tread portion 1, the sidewall portions 2, and the bead portions 3 each extend in the tire circumferential direction to form an annular shape, thereby constituting the toroidal basic structure of the pneumatic tire. Hereinafter, the description using FIG. 1 is basically based on the illustrated meridian cross-sectional shape, but each tire constituent member extends in the tire circumferential direction to form an annular shape.

[0017] A carcass layer 4 is mounted between the pair of left and right bead portions 3. The carcass layer 4 includes a plurality of reinforcing cords extending in the tire diameter direction, and is folded back from the inner side to the outer side in the tire width direction around a bead core 5 disposed in each bead portion 3. Further, a bead filler 6 is disposed on the outer periphery of the bead core 5, and this bead filler 6 is wrapped by the main body portion and the folded-back portion of the carcass layer 4. On the other hand, a plurality of belt layers 7 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. Each belt layer 7 includes a plurality of reinforcing cords inclined with respect to the tire circumferential direction, and the reinforcing cords are arranged so as to cross each other between the layers. In these belt layers 7, the inclination angle of the reinforcing cords with respect to the tire circumferential direction is set in the range of, for example, 10° to 40°. Further, at least one belt reinforcing layer 8 is provided on the outer peripheral side of the belt layer 7. The belt reinforcing layer 8 includes organic fiber cords oriented in the tire circumferential direction. In the belt reinforcing layer 8, the angle of the organic fiber cords with respect to the tire circumferential direction is set in the range of, for example, 0° to 5°.

[0018] A tread rubber layer 10 is disposed on the outer peripheral side of the carcass layer 4 in the tread portion 1, a side rubber layer 20 is disposed on the outer peripheral side (outer side in the tire width direction) of the carcass layer 4 in the sidewall portion 2, and a rim cushion rubber layer 30 is disposed on the outer peripheral side (outer side in the tire width direction) of the carcass layer 4 in the bead portion 3. The tread rubber layer 10 may have a structure in which two types of rubber layers having different physical properties (a cap tread layer constituting the tread surface of the tread portion 1 and an under tread layer disposed on the inner peripheral side thereof) are laminated in the tire diameter direction. The side rubber layer 20 is composed of a main body rubber layer 21 constituting the main portion of the sidewall portion 2 and a high-reflection rubber layer 22 described later that is exposed on a part of the outer surface of the sidewall portion 2.

[0019] Since the present invention relates to the sidewall portion 20 (particularly the high-reflection rubber layer 22), the basic structure (cross-sectional structure) of the tire in other portions is not limited to the above-described general structure.

[0020] In the present invention, as shown in FIG. 1, a highly reflective rubber layer 22 is disposed on the outer surface of the sidewall portion 2. The highly reflective rubber layer 22 is made of rubber having a higher light reflectance than the rubber (main body rubber layer 21) constituting the other portions of the sidewall portion 2, and its light reflectance is 70% or less, preferably 10% to 70%, more preferably 40% to 50%. In other words, since the main body rubber layer 21 is usually black rubber, the highly reflective rubber layer 22 is rubber having a color other than black (however, since the light reflectance is 70% or less, white rubber (white rubber) is excluded). By disposing rubber (highly reflective rubber layer 22) having a relatively high light reflectance compared to the surrounding rubber (main body rubber layer 21) in this way, the reflection of sunlight can be enhanced, and the temperature rise of the tire (sidewall portion 2) and the resulting increase in tire internal pressure can be suppressed. Further, due to the high light reflectance, the heat insulation effect is also enhanced, and this can also suppress the increase in tire internal pressure. If the light reflectance of the highly reflective rubber layer 22 is the same as or less than that of the main body rubber layer 21, the above-described effects cannot be obtained. Further, if the light reflectance of the highly reflective rubber layer 22 exceeds 70%, the rigidity of the rubber constituting the highly reflective rubber layer 22 decreases, and the rigidity of the sidewall portion 2 cannot be ensured, so the effect of improving handling stability is limited. Incidentally, even when the light reflectance of the highly reflective rubber layer 22 is higher than that of the main body rubber layer 21, if the light reflectance of the highly reflective rubber layer 22 is less than 10%, it is substantially equivalent to the main body rubber layer 21 (black rubber), so the effect of enhancing the reflection of sunlight is limited.

[0021] The color of the highly reflective rubber layer 22 is not particularly limited, but rubber in the gray system can be preferably used from the viewpoint of manufacturability. That is, the gray system rubber can appropriately adjust the shade of gray by adjusting the balance between the blending amount of carbon black, which is a factor in blackening the rubber in tire rubber, and the blending amount of materials (calcium carbonate, titanium oxide, etc.) adopted to obtain white in white rubber, and is suitable for obtaining a desired light reflectance.

[0022] If it has the above-mentioned light reflectance, the rubber formulation constituting the high-reflection rubber layer 22 is not particularly limited. For example, in the rubber composition constituting the high-reflection rubber layer 22, preferably 0.2 to 40 parts by mass, more preferably 3 to 20 parts by mass of a black filler (carbon black) and preferably 0.2 to 40 parts by mass, more preferably 10 to 30 parts by mass of a white filler (calcium carbonate, titanium oxide, etc.) are blended based on 100 parts by mass of the rubber component. Note that the more the amount of the white filler is blended, the closer the color of the rubber approaches white. When the blending amount exceeds 50 parts by mass, it substantially becomes white rubber (light reflectance of 70% or more), and sufficient rigidity cannot be ensured, so it is unsuitable for use in the high-reflection rubber layer of the present invention.

[0023] As described above, the high-reflection rubber layer 22 is provided to increase the light reflectance of the sidewall portion 2 and prevent the temperature of the sidewall portion 2 from rising when sunlight hits the sidewall portion 2. Therefore, the high-reflection rubber layer 22 is arranged so as to cover the member end portions that can be the starting points of cracks in the tire constituent members. Specifically, the high-reflection rubber layer 22 is arranged on the outer surface of the sidewall portion 2 at positions corresponding to the radially outer end portions of the bead filler 6 and / or the turned-up end portions of the carcass layer 4 in the tire radial direction. The high-reflection rubber layer 22 may be provided so as to cover only the position of the radially outer end portion of the bead filler 6 in the tire radial direction, or may be provided so as to cover only the position of the turned-up end portion of the carcass layer 4. However, as shown in FIGS. 1 and 2, it is preferable to provide it so as to cover both of these. In the example of FIG. 1, one layer of the high-reflection rubber layer 22 is arranged so as to cover both the radially outer end portion of the bead filler 6 and the turned-up end portion of the carcass layer 4 in the tire radial direction. However, as shown in FIG. 2, the high-reflection rubber layers 22 arranged at two positions may cover each part separately. In any of the embodiments of FIGS. 1 and 2, it is possible to suppress the temperature rise of the radially outer end portion of the bead filler 6 and the turned-up end portion of the carcass layer 4 that can be the starting points of cracks, and improve the crack resistance.

[0024] The high-reflection rubber layer 22 is intended to prevent the temperature of the sidewall portion 2 from rising when sunlight hits the sidewall portion 2 as described above. Therefore, the high-reflection rubber layer 22 may not be provided on the sidewall portion 2 on the side where sunlight is less likely to hit (that is, the sidewall portion 2 that is the inner side with respect to the vehicle when mounted on the vehicle). Specifically, when the pneumatic tire has a mounting direction display portion (not shown) indicating the mounting direction with respect to the vehicle, when the sidewall portion 2 located on the inner side of the vehicle at the time of vehicle mounting is defined as the inner sidewall portion and the sidewall portion 2 located on the outer side of the vehicle at the time of vehicle mounting is defined as the outer sidewall portion, the high-reflection rubber layer 22 is preferably disposed at least on the outer sidewall portion. In this case, by disposing the high-reflection rubber layer 22 on the outer sidewall portion, the temperature rise and the increase in internal pressure are suppressed, and the crack resistance and handling stability are improved. On the other hand, the side rigidity can be ensured without providing the high-reflection rubber layer 22 on the inner sidewall portion, and further improvement in handling stability may be achieved. Incidentally, the mounting direction display portion (not shown) is a display that designates the mounting direction of the front and back of the tire at the time of vehicle mounting, and is provided, for example, at a predetermined position on the sidewall portion 2. The content displayed as the mounting direction display portion is not particularly limited, but on the outer side of the vehicle, for example, "OUTSIDE" can be displayed along the tire circumferential direction, and on the inner side of the vehicle, for example, "INSIDE" can be displayed along the tire circumferential direction.

[0025] Regardless of the arrangement of the high-reflection rubber layer 22, the maximum thickness D of the high-reflection rubber layer 22 is preferably 1.0 mm or more and 3.0 mm or less, more preferably 1.0 mm or more and 2.0 mm or less. Thereby, the rigidity of the sidewall portion 2 can be ensured while ensuring appropriate light reflection performance. At this time, if the maximum thickness D of the high-reflection rubber layer 22 is less than 1.0 mm, the high-reflection rubber layer 22 is too thin, so the workability of the high-reflection rubber layer 22 decreases. If the maximum thickness D of the high-reflection rubber layer 22 exceeds 3.0 mm, it becomes difficult to sufficiently ensure the rigidity of the sidewall portion 2.

[0026] The tire radial length W of the highly reflective rubber layer 22 is preferably 10% to 50%, more preferably 15% or more and 30% or less of the tire section height SH. Thereby, the highly reflective rubber layer 22 comes to cover an appropriate range in the sidewall portion 2, and while ensuring the rigidity of the sidewall portion 2, it is possible to suppress the rise in tire temperature and the accompanying rise in tire internal pressure, which is advantageous for improving crack resistance and handling stability. At this time, when the tire radial length W of the highly reflective rubber layer 22 is less than 10% of the tire section height SH, the area that can reflect light becomes small, and the effect of suppressing the temperature rise and the internal pressure rise is limited. When the tire radial length W of the highly reflective rubber layer 22 exceeds 50% of the tire section height SH, it becomes difficult to sufficiently ensure the rigidity of the sidewall portion 2. Incidentally, when a plurality (for example, two places) of highly reflective rubber layers 22 spaced apart in the tire radial direction are provided as shown in FIG. 2, the tire radial length W is the sum of the tire radial lengths (w1 and w2 in the figure) of each highly reflective rubber layer 22 (W = w1 + w2).

[0027] The influence of the temperature rise of the sidewall portion 2 due to sunlight irradiation and the accompanying rise in internal pressure is significant in summer with long sunshine hours. Therefore, the above-described present invention is preferably adopted for summer tires and all-season tires used in summer rather than winter tires (such as studless tires) intended for use in winter.

[0028] Hereinafter, the present invention will be further described by way of examples, but the scope of the present invention is not limited to these examples.

Examples

[0029] Pneumatic tires of Comparative Example 1, Conventional Example 1, and Examples 1 to 5 were manufactured with a tire size of 235 / 60R18 103V, having the basic structure (cross-sectional structure) illustrated in FIG. 1, and with respect to the structure of the sidewall portion, the presence or absence of a highly reflective rubber layer, the light reflectivity [%] of the highly reflective rubber layer, the maximum thickness D [mm] of the highly reflective rubber layer, and the ratio [W / SH×100%] of the tire radial length W of the highly reflective rubber layer to the tire section height SH were set as shown in Table 1.

[0030] The light reflectance [%] of the highly reflective rubber layer is the ratio of the amount of light reflected by the sample (rubber constituting the highly reflective rubber layer) to the amount of light directly measured from the light source (the so-called "absolute reflectance"), and was measured using an integrating sphere attachment device (manufactured by Shimadzu Corporation) for the diffuse reflected light and specular reflected light (total light reflected light) when irradiating the reflective surface with light at an angle of 8 degrees with respect to the normal direction of the reflective surface of the sample. Incidentally, Conventional Example 1 is a tire without a highly reflective rubber layer, but in the column of "light reflectance of the highly reflective rubber layer" in Table 1, the value of the light reflectance of the rubber constituting the sidewall portion (corresponding to the main body rubber layer in other examples) is described for reference.

[0031] For these pneumatic tires, the tire internal pressure, crack resistance, and handling stability were evaluated by the following evaluation methods, and the results are shown in Table 1 together.

[0032] Tire internal pressure Each test tire was assembled onto a wheel (rim size: 18×7J) and mounted on a test vehicle (a four-wheel drive SUV with a displacement of 2500 cc), filled with an air pressure of 250 kPa, and test driven by a test driver on a domestic urban course, and the tire internal pressure was measured and recorded by the TPMS (tire air pressure sensor) mounted on each tire. The evaluation result showed the measured value of the maximum achievable internal pressure [unit: kPa]. The lower the value of the maximum achievable internal pressure, the more the increase in tire internal pressure could be suppressed.

[0033] Crack resistance Each test tire was assembled onto a wheel (rim size: 18×7J), and using an indoor drum tester (drum diameter: 1707 mm), under the conditions of an air pressure of 250 kPa, a load of the maximum load capacity × 120%, and a speed of 81 km / h, while irradiating the sidewall portion with solar-simulated light (light having a wavelength spectrum approximated to sunlight) by a solar-simulated light irradiator (manufactured by Mitsubishi Heavy Industries Thermal Systems), a running test was carried out until cracks occurred in the tire, and the running distance until cracks occurred in the tire was measured. The evaluation results are shown in the following three levels. A: The running distance until cracks occur is 6480 km or more B: The driving distance until a crack occurs is 5,670 km or more and less than 6,480 km C: The driving distance until a crack occurs is less than 5,670 km

[0034] Ride and handling Each test tire was assembled onto a wheel (rim size: 18×7J) and mounted on a test vehicle (a four-wheel drive SUV with a displacement of 2,500 cc). After filling the tires with an air pressure of 250 kPa and leaving them outdoors for 3 hours on a sunny day, a sensory evaluation of the ride and handling by a test driver was conducted on a domestic urban course. The evaluation results were shown as an index with the conventional example set to 100. A larger value of this index means better ride and handling performance.

[0035] [Table 1]

[0036] As is clear from Table 1, the pneumatic tires of Examples 1 to 5 suppressed the increase in tire internal pressure and improved crack resistance and ride and handling. On the other hand, in Comparative Example 1 where the light reflectance of the highly reflective rubber layer was too high (a pneumatic tire using white rubber as the highly reflective rubber layer), although the effect of suppressing the increase in tire temperature and the effect of suppressing tire internal pressure could be expected, the ride and handling deteriorated because the decrease in the rigidity of the sidewall portion due to white rubber was significant.

[0037] This disclosure includes the following inventions. Invention [1] A pneumatic tire having a tread portion extending in the tire circumferential direction and forming an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the tire radial direction inner side of these sidewall portions, a bead core disposed in each of the bead portions, a bead filler disposed on the tire radial direction outer side of the bead core, and at least one carcass layer mounted between the pair of bead portions, On the outer surface of the sidewall portion corresponding to the radially outer end of the bead filler and / or the end of the carcass layer, a high-reflection rubber layer is provided, which has a higher light reflectivity than the rubber constituting the other parts of the sidewall portion and a light reflectivity of 70% or less. The pneumatic tire is characterized by this. Invention [2] The pneumatic tire according to invention [1], characterized in that the high-reflection rubber layer is provided on the outer surface of the sidewall portion corresponding to the radially outer end of the bead filler and the end of the carcass layer. Invention [3] The pneumatic tire according to invention [1] or [2], characterized in that the light reflectivity of the high-reflection rubber layer is 10% or more. Invention [4] The pneumatic tire according to any one of inventions [1] to [3], characterized in that the radial length W of the high-reflection rubber layer is 10% to 50% of the tire cross-sectional height SH. Invention [5] The pneumatic tire according to any one of inventions [1] to [4], characterized in that the thickness of the high-reflection rubber layer is 1.0 mm or more and 3.0 mm or less. Invention [6] It has a mounting direction display portion indicating the mounting direction with respect to the vehicle. The pair of sidewall portions consists of an inner sidewall portion located inside the vehicle when mounted on the vehicle and an outer sidewall portion located outside the vehicle when mounted on the vehicle. The pneumatic tire according to any one of inventions [1] to [5], characterized in that the high-reflection rubber layer is provided on at least the outer sidewall portion.

Explanation of reference numerals

[0038] 1 Tread portion 2 Sidewall portion 3 Bead portion 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Belt reinforcing layer 10 Tread rubber layer 20 Side rubber layer 21 Body rubber layer 22 High-reflection rubber layer 30 Rim cushion rubber layer CL Tire equator

Claims

1. An inflated tire having a tread portion extending in the tire circumferential direction to form an annular shape, a pair of sidewall portions disposed on both sides of the tread portion, and a pair of bead portions disposed on the radially inner side of these sidewall portions in the tire diameter direction, a bead core disposed in each of the bead portions, a bead filler disposed on the radially outer side of the bead core in the tire diameter direction, and at least one carcass layer mounted between the pair of bead portions, wherein a high-reflection rubber layer having a higher light reflectivity than the rubber constituting the other portions of the sidewall portion and a light reflectivity of 70% or less is provided on the outer surface of the sidewall portion corresponding to the radially outer end portion of the bead filler and / or the end portion of the carcass layer.

2. The inflated tire according to claim 1, wherein the high-reflection rubber layer is provided on the outer surface of the sidewall portion corresponding to the radially outer end portion of the bead filler and the end portion of the carcass layer.

3. The inflated tire according to claim 1 or 2, wherein the light reflectivity of the high-reflection rubber layer is 10% or more.

4. The inflated tire according to claim 1 or 2, wherein the tire diameter direction length W of the high-reflection rubber layer is 10% to 50% of the tire cross-sectional height SH.

5. The inflated tire according to claim 1 or 2, wherein the thickness of the high-reflection rubber layer is 1.0 mm or more and 3.0 mm or less.

6. Having a mounting direction display portion indicating the mounting direction with respect to the vehicle, the pair of sidewall portions being composed of an inner sidewall portion located on the inner side of the vehicle when mounted on the vehicle and an outer sidewall portion located on the outer side of the vehicle when mounted on the vehicle, and the high-reflection rubber layer being provided on at least the outer sidewall portion.

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