Pneumatic tire

Abstract

Provided is a pneumatic tire having an excellent appearance of a side portion. The pneumatic tire has a pair of side portions (3). A first region (10) having a first surface (11) and a second region (20) having a second surface (21) that is convex or concave in a side portion thickness direction with respect to the first surface (11) are formed on a surface of at least one of the pair of side portions (3). A concave-convex portion (22) is formed on the second surface (21). The height of the concave-convex portion (22) is smaller than the relative distance in the side portion thickness direction between the first surface (11) and the second surface (21). The first surface (11) is smoother than the second surface (21). The first region (10) and the second region (20) are alternately arranged in a tire circumferential direction and a tire radial direction.

Description

Technical Field

[0001] This invention relates to a pneumatic tire. Background Technology

[0002] Typically, the sidewalls of pneumatic tires are covered with a thin layer of rubber. Therefore, due to seams in the tire carcass (an internal structural material) or residual air, localized bumps or depressions, known as bulges or dents, can easily appear on the sidewalls. While these bumps do not affect tire performance, they give the tire an undesirable appearance.

[0003] In order to make the unevenness less noticeable, various pneumatic tires with decorative patterns formed on the surface of the sidewall have been proposed (for example, see Patent Document 1 below).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2014-136487 Summary of the Invention

[0005] In recent years, there has been a growing demand for making the sidewalls less concave and improving their appearance.

[0006] The present invention was made in view of the above problems, and its main objective is to provide a pneumatic tire with an excellent sidewall appearance.

[0007] The present invention is a pneumatic tire having a pair of sidewalls, wherein at least one sidewall of the pair of sidewalls has formed on its surface: a first region having a first surface; and a second region having a second surface that is raised or recessed relative to the first surface in the thickness direction of the sidewall, wherein a protrusion or depression is formed on the second surface, the height of the protrusion or depression being smaller than the relative distance in the thickness direction of the sidewall between the first surface and the second surface, the first surface being smoother than the second surface, and the first region and the second region being alternately arranged in the circumferential and radial directions of the tire.

[0008] In the pneumatic tire of the present invention, it is preferable that the at least one sidewall portion has a radial second region column formed by arranging a plurality of second regions in the radial direction of the tire, the radial second region column being inclined relative to the radial direction of the tire.

[0009] In the pneumatic tire of the present invention, preferably, the concave and convex portions include a plurality of protrusions extending in a linear manner.

[0010] In the pneumatic tire of the present invention, preferably, the linear protrusion is inclined relative to the radial direction of the tire.

[0011] In the pneumatic tire of the present invention, preferably, two adjacent second regions in the tire circumferential direction include portions that overlap each other in the tire radial direction.

[0012] In the pneumatic tire of the present invention, preferably, two second regions that are adjacent in the radial direction of the tire include portions that overlap each other in the circumferential direction of the tire.

[0013] In the pneumatic tire of the present invention, preferably, the second region is a rectangle comprising a first edge extending circumferentially along the tire and a second edge extending circumferentially along the tire at a location radially outward from the first edge.

[0014] In the pneumatic tire of the present invention, preferably, the length of the second edge is greater than the length of the first edge.

[0015] In the pneumatic tire of the present invention, it is preferable that a plurality of protrusions extending in a linear manner are arranged parallel to each other on the concave and convex portions, and that the height of each of the protrusions is greater the closer it is to the first region in the cross-section of the plurality of protrusions.

[0016] In the pneumatic tire of the present invention, it is preferable that the second surface is more concave than the first surface.

[0017] In the pneumatic tire of the present invention, it is preferable that the second surface protrudes more than the first surface.

[0018] By employing the aforementioned structure, the present invention enables the provision of a pneumatic tire with an excellent sidewall appearance. Attached Figure Description

[0019] Figure 1 This is an enlarged view of the sidewall of the tire according to this embodiment.

[0020] Figure 2 yes Figure 1 A magnified 3D view of the second region.

[0021] Figure 3 This is an enlarged view of the sidewall of another embodiment.

[0022] Figure 4 This is an enlarged view of the sidewall of another embodiment.

[0023] Figure 5 This is an enlarged view of the sidewall of another embodiment.

[0024] Figure 6 yes Figure 2 A cross-sectional view of the concave and convex parts.

[0025] Figure 7 This is a cross-sectional view of the protrusions and recesses in other embodiments.

[0026] Figure 8 This is an enlarged perspective view of the second region in other embodiments.

[0027] Figure 9This is an enlarged perspective view of the second region in other embodiments.

[0028] Figure 10 This is an enlarged perspective view of the second region in other embodiments.

[0029] Figure 11 This is an enlarged view of the sidewall of the comparative example tire.

[0030] Label Explanation

[0031] 3: Sidewall; 11: First surface; 10: First region; 21: Second surface; 20: Second region; 22: Concave / convex portion. Detailed Implementation

[0032] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0033] Figure 1 This is an enlarged view of the sidewall portion 3 of the pneumatic tire (hereinafter, sometimes simply referred to as "tire") 1 according to this embodiment. The tire 1 of this embodiment has a pair of sidewall portions 3 on both sides of the tread portion 2. The tire 1 of this embodiment is used for passenger cars. However, the present invention is not limited to this method, and can also be applied, for example, to tires for motorized two-wheeled vehicles and heavy-duty tires.

[0034] In this specification, unless otherwise specified, the dimensions of all parts of tire 1 are measured under standard conditions. "Standard conditions" refers to the state where, for pneumatic tires of various specifications, the tire is assembled on a standard rim, inflated to the standard internal pressure, and unloaded. Where tire specifications are not specified, the standard conditions refer to the standard operating condition corresponding to the tire's intended use, i.e., the unloaded state. Furthermore, the structures described in this specification allow for the typical errors inherent in rubber molded products.

[0035] "Standard rim" refers to a rim that meets the specifications of the tire within a specification system that includes the specifications on which the tire is based. For example, if it is JATMA, it is "standard rim"; if it is TRA, it is "Design Rim"; and if it is ETRTO, it is "Measuring Rim".

[0036] "Standard internal pressure" refers to the air pressure specified for each tire specification within the specification system, including the tire's base specification. For JATMA, it is the "maximum air pressure"; for TRA, it is the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUSCOLD INFLATION PRESSURES"; and for ETRTO, it is "INFLATION PRESSURE".

[0037] In the tire 1 of this embodiment, a first region 10 having a first surface 11 and a second region 20 having a second surface 21 that protrudes or is recessed relative to the first surface 11 in the sidewall thickness direction are formed on at least one surface of a pair of sidewall portions 3. The "sidewall thickness direction" refers to the thickness direction of the rubber disposed on the outer side of the tire body that constitutes the sidewall portion.

[0038] The relative distance in the thickness direction of the sidewall portion between the first surface 11 and the second surface 21 is, for example, 2.0 mm or less. This distance is preferably 0.2 mm to 1.5 mm, more preferably 0.4 mm to 1.0 mm. However, the present invention is not limited to this method.

[0039] Figure 2 This is an enlarged perspective view showing the second region 20 of this embodiment. (As shown...) Figure 2 As shown, a protrusion 22 is formed on the second surface 21 of the second region 20. In this embodiment, the protrusion 22 comprises a plurality of linearly extending protrusions 23. The term "linearly extending protrusion" refers to a protrusion that extends in any direction from its top, such that it has a length direction along that arbitrary direction and a width direction orthogonal to it. In this embodiment, the protrusions 23 extend in a straight line, but they can also extend in a curved manner. However, the protrusions 23 are not limited to this shape. The height of the protrusion 22 is smaller than the relative distance in the thickness direction of the sidewall portion between the first surface 11 and the second surface 21.

[0040] Furthermore, the first surface 11 is smoother than the second surface 21. That is, even when the first surface 11 is planar or has unevenness, the average value of its unevenness height is less than the average value of the unevenness height of the unevenness portion 22 of the second surface 21. Additionally, the structure refers to a form such that, at least when a tire user observes the first surface 11 and the second surface 21 with normal attention, they can identify that the first surface 11 is flatter than the second surface 21. In this embodiment, the first surface 11 is a planar surface without any unevenness that can be visually identified.

[0041] In addition, such as Figure 1 As shown, in this invention, the first region 10 and the second region 20 are alternately arranged along the tire circumferential and radial directions. The pneumatic tire of this invention, by employing the aforementioned structure, can provide a pneumatic tire with an excellent appearance of the sidewall portion 3. The reason for this is presumably due to the following mechanism.

[0042] In this invention, a raised portion 22 is formed on the second surface 21, while the first surface 11 is smoother than the second surface 21, thus creating a contrast of light between the first surface 11 and the second surface 21. In particular, the raised portion 22 creates this contrast even when the sidewall portion 3 is viewed from various directions. Therefore, an observer of the surface of the sidewall portion 3 will easily notice the first region 10 and the second region 20, and there is a tendency to make the localized raised or recessed features of the sidewall portion 3 less noticeable. Based on this mechanism, it is speculated that a pneumatic tire could be developed that makes the raised or recessed features less noticeable, thereby achieving an excellent appearance for the sidewall portion 3.

[0043] The structure of this embodiment will be described in more detail below. Figure 1 As shown, the sidewall portion 3 of this embodiment is provided with a plurality of second regions 20, and the outer surface, except for the second regions 20, is generally a smooth surface.

[0044] The shape of the second region 20 (which is the shape formed by the boundary with the first region 10) is, for example, rectangular. In this embodiment, the second region 20 is formed as a transversely elongated rectangle with a length in the tire circumferential direction greater than the tire radial direction. The second region 20 includes a first edge 20a extending in the tire circumferential direction and a second edge 20b extending in the tire circumferential direction further outward of the tire radial direction than the first edge 20a. The second region 20 is a rectangular shape in which the first edge 20a and the second edge 20b have the same length. The length of each side is not particularly limited, for example, in the range of 2 mm to 10 mm, preferably 4 mm to 8 mm. Furthermore, the length of the third edge 20c extending from the first edge 20a to the second edge 20b is less than the length of the first edge 20a. The length of the third edge 20c is, for example, 35% to 75% of the length of the first edge 20a, preferably 45% to 65%. As a result, the appearance of the sidewall portion 3 is further improved.

[0045] Furthermore, the shape of the second region 20 is not limited to this form. The shape of the second region 20 can be various shapes, such as square, trapezoid, polygon, circle, ellipse, etc.

[0046] The sidewall portion 3 of this embodiment has a radial second region row 25 formed by arranging a plurality of second regions 20 in the radial direction of the tire. The radial second region row 25 of this embodiment includes a plurality of second regions 20 arranged in the radial direction of the tire. Such a radial second region row 25 can effectively make the bumps and depressions formed in the sidewall portion less noticeable (hereinafter, such effect is sometimes referred to as improved concealment performance).

[0047] The sidewall portion 3 includes multiple radial rows of second regions 25 in the tire circumferential direction. Thus, in the sidewall portion 3, second regions 20 are also arranged in the tire circumferential direction.

[0048] The configuration of the second region 20 is not limited to the method described above. Figures 3-5 An enlarged view of the sidewall portion 3 of a tire according to another embodiment of the present invention.

[0049] like Figure 3 As shown, in this embodiment, the radial second region row 25 is inclined relative to the tire radially. This arrangement of the second region 20 allows for adjustment of the airflow along the outer surface of the tire sidewall 3 during driving. As a result, for example, a reduction in tire air resistance during driving can be expected.

[0050] In this embodiment, the imaginary line 24 connecting the centroids 20d of adjacent radially adjacent second regions 20 of the tire is inclined at an angle of 45° or less relative to the tire radial direction. The angle of the imaginary line 24 relative to the tire radial direction is preferably 10° to 45°, more preferably 20° to 40°. This results in excellent concealment performance. Furthermore, in this embodiment, the inclination of the radially arranged second region row 25 and the inclination of the linearly extending protrusion 23 work together to further enhance concealment performance.

[0051] exist Figure 3 In the illustrated embodiment, in a more preferred manner, the angle θ1 of the imaginary line 24 relative to the tire circumference and the angle θ2 of the linearly extending protrusion 23 relative to the tire circumference preferably satisfy the following equation (1). This further improves concealment performance.

[0052] 45°<θ1≤θ2···(1)

[0053] like Figure 4 As shown, the radial second region column 25 of this embodiment includes a plurality of horizontally elongated rectangular second regions 20 that are inclined relative to the tire radial direction.

[0054] In this embodiment, the linear protrusion 23 of the second region 20 is inclined relative to the tire radial direction. The angle between the linear protrusion 23 and the tire radial direction is preferably 20° or more, more preferably 30° or more, further preferably 35° or more, and preferably 60° or less, more preferably 50° or less, and even more preferably 45° or less. Thus, the overall inclination of the second region 20 and the inclination of the protrusion 23 work together to achieve high concealment performance. Furthermore, if in Figure 2 By applying the aforementioned structure to the recessed second region 20 shown, molding defects during vulcanization can be effectively suppressed. Hereinafter, this effect will be referred to as "improved vulcanization moldability".

[0055] In this embodiment, in a more preferred manner, the angle θ3 of the imaginary line 24 connecting the centroid 20d of the second region 20 with respect to the tire circumference and the angle θ4 of the linear protrusion 23 of the second region 20 with respect to the tire circumference preferably satisfy the following equation (2). This further improves concealment performance. Furthermore, this arrangement of the second region 20 and the protrusion 23 also helps to disperse the frequency band of noise caused by the turbulence they generate, suppressing the deterioration of noise performance.

[0056] 45°<θ4<60°<θ3···(2)

[0057] Preferably, two adjacent second regions 20 in the tire circumferential direction include portions that overlap in the tire radial direction. That is, an imaginary region extending from one of the two second regions 20 along the tire circumferential direction overlaps with the other of the two second regions 20. The overlap length of the imaginary region in the tire radial direction is preferably 50% or more, more preferably 80% or more, of the tire radial length of one second region 20. In this embodiment, the two second regions 20 overlap entirely.

[0058] Furthermore, preferably, two adjacent second regions 20 in the tire radial direction include portions that overlap each other in the tire circumferential direction. That is, in the two second regions 20, an imaginary region extending radially from one second region 20 overlaps with the other of the two second regions 20. The overlap length of the imaginary regions in the tire circumferential direction is preferably 50% or more, more preferably 80% or more, of the tire circumferential length of one second region 20. In this embodiment, the two second regions 20 overlap entirely. In this embodiment, through the synergistic effect of the structure and the linear extension of the protrusion 23, higher concealment performance can be expected.

[0059] exist Figure 5 In the illustrated embodiment, the second region 20 is trapezoidal in shape. In this embodiment, the first edge 20a extending circumferentially along the tire and the second edge 20b extending circumferentially along the tire radially outward from the first edge 20a are parallel to each other, and the length of the second edge 20b is greater than the length of the first edge 20a. The length of the second edge 20b is, for example, less than 2.0 times the length of the first edge 20a. The length of the second edge 20b is preferably 1.1 to 1.8 times the length of the first edge 20a, more preferably 1.2 to 1.5 times. This results in excellent concealment performance. In particular, if in Figure 5 The second regions 20 in the configuration shown are combined with a structure that tilts the linear protrusions 23 relative to the radial direction of the tire, which makes the tread pattern on the outer surface of the tire sidewall more complex and can be expected to further improve the concealment performance.

[0060] like Figure 2 As shown, in this embodiment, the second surface 21 is recessed compared to the first surface 11. However, it is not limited to this arrangement; as will be described later, the second surface 21 may also protrude compared to the first surface 11.

[0061] The protrusions 22 are configured, for example, such that the plurality of protrusions 23 extending in a linear manner are arranged parallel to each other. The "parallelism of the plurality of protrusions 23" includes the error that is usually present in rubber products, including the manner in which the angle difference of the plurality of protrusions 23 is less than 5°.

[0062] Figure 6 This represents a cross-section orthogonal to the length direction of the plurality of protrusions 23. For example... Figure 6 As shown, the cross-sectional shape of the protrusion 23 is, for example, trapezoidal. In this embodiment, excellent vulcanizability is achieved by arranging the protrusion 23 with a trapezoidal cross-section in the recessed second region 20. However, it is not limited to this shape; the cross-sectional shape of the protrusion 23 may also be, for example, semi-circular or triangular.

[0063] The height h1 of each protrusion 23 is, for example, smaller than the relative distance d1 in the thickness direction of the sidewall portion between the first surface 11 and the second surface 21. The height h1 of the protrusion 23 is preferably 40% or more of the relative distance d1, more preferably 50% or more, and preferably 80% or less, more preferably 70% or less. This achieves the aforementioned effect and suppresses poor vulcanization molding.

[0064] The protrusion 23 includes two inclined surfaces 23a extending from the second surface 21. The angle θ5 between the two inclined surfaces 23a is, for example, 10° to 90°, preferably 20° to 40°. In addition, the width W1 of the protrusion 23 is, for example, 0.2 mm to 0.6 mm.

[0065] exist Figure 3 In the illustrated embodiment, the relative distance d1 is preferably less than the tire circumferential position offset L1 of the second region 20 adjacent in the tire radial direction. Specifically, the relative distance d1 and the position offset L1 preferably satisfy the following equation (3). Thus, while fully utilizing the concealment performance, excessive changes in the rubber thickness of the sidewall portion 3 can be suppressed, and the durability of the sidewall portion 3 is improved.

[0066] 0.01L1 <d1<0.30L2···(3)

[0067] exist Figure 3 In the embodiment shown, the angle θ5 of the protrusion 23 ( Figure 6As shown), the angle θ2 of the protrusion relative to the tire circumference and the angle θ1 of the imaginary line 24 relative to the tire circumference preferably have the relationship of the following formula (4). As a result, the light reflected by the sidewall 3 is more easily dispersed, further improving the concealment effect.

[0068] θ5<θ1<θ2···(4)

[0069] exist Figure 4 In the illustrated embodiment, the relationship between the tire radial overlap length L2 of two adjacent second regions 20 in the tire circumferential direction, the tire radial overlap length L3 of two adjacent second regions 20 in the tire radial direction, and the relative distance d1 preferably satisfies the following equation (5). By specifying the upper limit of the relative distance d1 as described above, excessive reduction of the rubber thickness of the sidewall portion can be suppressed, and the durability of the sidewall portion 3 can be improved.

[0070] d1 <L3≤L2···(5)

[0071] exist Figure 4 In a more preferred embodiment shown, the relationship between the relative distance d1, the total length L4 of the protrusion 23, and the angle θ5 of the protrusion relative to the radial direction of the tire preferably satisfies the following equation (6). Thus, for example, it is possible to suppress the formation of a notch in the protrusion 23 when the second region 20 collides with a curb or similar object, while simultaneously achieving excellent shielding effect.

[0072] d1 <L2×sinθ5···(6)

[0073] Figure 7 Other embodiments of the protrusion / recess 22 are shown. For example... Figure 7 As shown, in this embodiment, in the cross-section of the plurality of protrusions 23, the height of each protrusion 23 increases as it approaches the first region 10. The maximum height h2 of the protrusion 23 in a single concave-convex portion 22 is, for example, 50% to 95% of the relative distance d1 in the thickness direction of the sidewall portion between the first surface 11 and the second surface 21, preferably 70% to 80%. The minimum height h3 of the protrusion 23 in a single concave-convex portion 22 is, for example, 5% to 50% of the relative distance d1, preferably 20% to 30%. Such concave-convex portions 22 provide a gradient to the second region 20, further improving concealment performance. In addition, the vulcanizing mold forming the concave-convex portions 22 helps to suppress air retention and improves vulcanization molding.

[0074] In particular, by applying the protrusions and recesses 22 to Figures 3-5 The second region 20 shown in the diagram can improve both concealment performance and vulcanization molding properties in a balanced way.

[0075] Figures 8-10 An enlarged perspective view of the second region 20 in another embodiment. (e.g.) Figure 8 As shown, the second surface 21 of the second region 20 protrudes from the first surface 11. This second surface 21, during driving, guides air flowing on the outer surface of the tire sidewall 3 towards the wheel arch side, thereby generating downforce that pushes the tire towards the road surface. Furthermore, this second region 20 facilitates heat dissipation during driving, helping to cool the outer surface of the tire sidewall 3. This improves the durability of the tire sidewall 3.

[0076] In addition, by applying the linearly extending protrusion 23 in the second region 20 of this embodiment, in addition to improving concealment performance, heat dissipation is also improved, and the durability of the sidewall portion 3 is further improved.

[0077] Figure 9 The second surface 21 of the second region 20 shown is recessed compared to the first surface 11, and a plurality of trapezoidal conical protrusions 23 are provided on the second surface 21. This second region 20 reflects light in multiple directions, increasing the contrast with the first region 10. Furthermore, by applying the aforementioned structure... Figures 3-5 The second region 20 shown in the diagram further enhances concealment.

[0078] Figure 10 The second surface 21 of the second region 20 shown protrudes beyond the first surface 11, and a plurality of trapezoidal conical protrusions 23 are provided on the second surface 21. This second region 20 provides excellent concealment, and the protruding second region 20 also provides high heat dissipation. Therefore, the second region 20 of this embodiment contributes to improving the durability of the tire sidewall 3.

[0079] In addition, through Figures 3-5 Applying the structure to the second region 20 of the configuration shown further improves concealment performance, and each second region 20 can function as a protective part of the tire sidewall 3. Therefore, such a structure can also improve the durability of the tire sidewall 3 during off-road driving.

[0080] Furthermore, the aforementioned structures can, of course, be combined separately and applied to pneumatic tires.

[0081] The above describes in detail the particularly preferred embodiments of the present invention, but the present invention is not limited to the embodiments shown in the figures and can be implemented in various ways.

[0082]

Example

[0083] Manufacturing includes Figure 1 The tire shown has a sidewall size of 205 / 55R16. As a comparative example, a prototype with... Figure 11The pneumatic tire with sidewall a shown is an example. The comparative example's sidewall a has multiple regions c recessed from a planar region b, the outer surface of which, like region b, is planar. It is substantially the same as the tire of the embodiment. The concealment performance of each test tire was tested. The general specifications and test methods for the test tires are described below.

[0084] Wheel rim installation: 16×6.5J

[0085] Tire internal pressure: 200 kPa

[0086] <Concealment Performance>

[0087] On a sunny outdoor day, the outer surface of the tire sidewall was visually inspected from all directions, and the occurrence of bumps and dents on the sidewall was evaluated by the observers' senses. The evaluation was conducted by 20 evaluators. Each evaluator rated the concealment performance of each test tire on a 5-point scale (1 to 5). The total score from the 20 evaluators for each test tire became the concealment performance rating. The results were converted from the total score of the comparative examples to 100, with a higher value indicating better concealment performance.

[0088] The test results are shown in Table 1.

[0089] Table 1

[0090] Comparative example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Diagram showing the sidewall of the tire Figure 11 Figure 1 Figure 3 Figure 4 Figure 5 Figure 1 Figure 1 Figure 1 The diagram representing the second region - Figure 2 Figure 2 Figure 2 Figure 2 Figure 7 Figure 8 Figure 9 Concealment Performance (Rating) 100 120 122 124 126 120 118 118

[0091] As a result of the tests, the tire of the embodiment effectively minimized the appearance of unevenness on the sidewall. That is, in this invention, it can be confirmed that a pneumatic tire can provide an excellent appearance on the sidewall.

Claims

1. A pneumatic tire having a pair of sidewalls, wherein, At least one of the pair of sidewall portions has the following formed on its surface: a first region having a first surface; and a second region having a second surface that is raised or recessed relative to the first surface in the sidewall thickness direction. The second surface has irregularities formed thereon. The height of the uneven portion is smaller than the relative distance in the thickness direction of the sidewall portion between the first surface and the second surface. The first surface is smoother than the second surface. The first region and the second region are alternately arranged in the tire circumferential and tire radial directions. The concave and convex portions are arranged parallel to each other and extend in a linear manner. The second region is rectangular, and each of the multiple protrusions in each second region is connected to the longer of the two sets of opposite sides of the rectangular second region, and all the multiple protrusions in each second region are inclined relative to the tire radially.

2. A pneumatic tire having a pair of sidewalls, wherein, At least one of the pair of sidewall portions has the following formed on its surface: a first region having a first surface; and a second region having a second surface that is raised or recessed relative to the first surface in the sidewall thickness direction. The second surface has irregularities formed thereon. The height of the uneven portion is smaller than the relative distance in the thickness direction of the sidewall portion between the first surface and the second surface. The first surface is smoother than the second surface. The first region and the second region are alternately arranged in the tire circumferential and tire radial directions. The concave and convex portions are arranged parallel to each other and extend in a linear manner. The second region is rectangular, and each of the multiple protrusions in each second region is connected to the longer of the two sets of opposite sides of the rectangular second region. Furthermore, all the multiple protrusions in each of the second regions are inclined radially relative to the tire. In the cross-section of the plurality of protrusions, the closer to the first region, the greater the height of each protrusion.

3. A pneumatic tire having a pair of sidewalls, wherein, At least one of the pair of sidewall portions has the following formed on its surface: a first region having a first surface; and a second region having a second surface that is raised or recessed relative to the first surface in the sidewall thickness direction. The second surface has irregularities formed thereon. The height of the uneven portion is smaller than the relative distance in the thickness direction of the sidewall portion between the first surface and the second surface. The first surface is smoother than the second surface. The first region and the second region are alternately arranged in the tire circumferential and tire radial directions. The concave and convex portions are arranged parallel to each other and extend in a linear manner. The at least one sidewall portion has a radial second region row formed by arranging a plurality of the second regions radially in the tire direction. The angle θ3 of the imaginary line connecting the centroids of the plurality of second regions contained in the radial second region column with respect to the tire circumference and the angle θ4 of the linearly extending protrusion with respect to the tire circumference satisfy the following equation (2). 45°<θ4<60°<θ3···(2), By satisfying the above equation (2), such a configuration of the second region and the protrusion helps to disperse the frequency band of the noise caused by the turbulence generated by them.

4. A pneumatic tire having a pair of sidewalls, wherein, At least one of the pair of sidewall portions has the following formed on its surface: a first region having a first surface; and a second region having a second surface that is raised or recessed relative to the first surface in the sidewall thickness direction. The second surface has irregularities formed thereon. The height of the uneven portion is smaller than the relative distance in the thickness direction of the sidewall portion between the first surface and the second surface. The first surface is smoother than the second surface. The first region and the second region are alternately arranged in the tire circumferential and tire radial directions. The concave and convex portions are arranged parallel to each other and extend in a linear manner. The linearly extending protrusion includes two inclined surfaces extending from the second surface in a cross-section orthogonal to its length direction. The at least one sidewall portion has a radial second region row formed by arranging a plurality of the second regions radially in the tire direction. The angle θ1 of the imaginary line connecting the centroids of the plurality of second regions contained in the radial second region column relative to the tire circumference, the angle θ2 of the linearly extending convex portion relative to the tire circumference, and the angle θ5 between the two inclined surfaces of the convex portion satisfy the following equation (4). θ5<θ1<θ2···(4) By satisfying the above equation (4), the light reflected by the tire side is more easily dispersed.

5. The pneumatic tire according to claim 4, wherein, The at least one sidewall portion has a radial second region row formed by arranging a plurality of the second regions radially in the tire direction. The second radial region column is inclined relative to the tire radial direction.

6. The pneumatic tire according to claim 3 or 4, wherein, The linear protrusion is inclined relative to the radial direction of the tire.

7. The pneumatic tire according to any one of claims 1 to 4, wherein, The two second regions that are adjacent in the tire circumferential direction are the portions that overlap each other in the tire radial direction.

8. The pneumatic tire according to any one of claims 1 to 4, wherein, The two second regions that are adjacent in the radial direction of the tire are contained in the portions that overlap each other in the circumferential direction of the tire.

9. The pneumatic tire according to claim 4, wherein, The second region is a rectangle comprising a first edge extending circumferentially along the tire and a second edge extending circumferentially along the tire at a location radially outward from the first edge.

10. The pneumatic tire according to claim 4, wherein, The second region is a trapezoid comprising a first edge extending circumferentially along the tire and a second edge extending circumferentially along the tire at a location radially outward from the first edge, the length of the second edge being greater than the length of the first edge.

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