pneumatic tires

Abstract

To provide a pneumatic tire with improved sidewall aesthetics. [Solution] The tire sidewall portion 2 has a first undecorated region 3 having a smooth surface, and a decorated region 4 adjacent to the first undecorated region 3 and decorated with a plurality of ridges 41. The decorated region 4 has a recess that is indented relative to the smooth surface. The plurality of ridges 41 protrude from the bottom of the recess. The protruding height of the plurality of ridges 41 is greater than the depth of the recess. In a cross-section passing through the plurality of ridges 41, the vertex angle of the ridges 41 is 40 degrees or more and 80 degrees or less.

Description

Technical Field

[0001] This disclosure relates to pneumatic tires.

Background Art

[0002] In order to improve the aesthetics of the sidewall portion of a tire, it is known that a decorative area decorated with a plurality of ridges is provided on the sidewall portion of a pneumatic tire (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Improvement in the aesthetics of the sidewall portion is required.

[0005] This disclosure provides a pneumatic tire with improved aesthetics of the sidewall portion.

Means for Solving the Problems

[0006] The pneumatic tire of this disclosure includes a sidewall portion having a first undecorated area with a smooth surface and a decorative area adjacent to the first undecorated area and decorated with a plurality of ridges. The decorative area has a concave portion recessed with respect to the smooth surface, the plurality of ridges protrude from the bottom of the concave portion, the protruding height of the plurality of ridges is greater than the depth of the concave portion, and the apex angle of the ridges in a cross section passing through the plurality of ridges is 40 degrees or more and 80 degrees or less.

Brief Description of the Drawings

[0007] [Figure 1] It is a view showing a part of the outer surface of the sidewall portion as viewed from the outside in the tire axial direction. [Figure 2] This is a diagram showing the main parts of Figure 1. [Figure 3] Figure 3(A) is a cross-sectional view taken along the arrow AA in Figure 1. Figure 3(B) is a cross-sectional view taken along the arrow BB in Figure 2. Figure 3(C) is a cross-sectional view taken along the arrow CC in Figure 2. Figure 3(D) is a cross-sectional view taken along the arrow DD in Figure 2. Figure 3(E) is a cross-sectional view taken along the arrow EE in Figure 2. [Figure 4] Figure 4(F) is a cross-sectional view taken along the FF arrow in Figure 2. Figure 4(G) is a cross-sectional view taken along the GG arrow in Figure 6. Figure 4(H) is a cross-sectional view taken along the HH arrow in Figure 6. Figure 4(J) is a cross-sectional view taken along the JJ arrow in Figure 6. [Figure 5] This is an enlarged view showing the first main part in Figure 2. [Figure 6] This is an enlarged view showing the second main part in Figure 2. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of this disclosure will be described with reference to the drawings.

[0009] <Basic Tire Structure> The tire radial direction is the direction along the tire's diameter. The inner direction in the tire radial direction is the direction approaching the tire's axis of rotation. The outer direction in the tire radial direction is the direction away from the tire's axis of rotation. The tire axial direction is the direction parallel to the tire's axis of rotation. The inner direction in the tire axial direction is the direction approaching the tire's equatorial plane (not shown). The outer direction in the tire axial direction is the direction away from the tire's equatorial plane. The tire's equatorial plane is a virtual plane located at the center of the tire's axial direction and perpendicular to the tire's axis of rotation. The tire circumferential direction CD (see Figure 1) is the direction around the tire's axis of rotation.

[0010] Although not shown in the diagram, the tire has a pair of bead sections, a pair of sidewall sections 2 (see Figure 1) extending radially outward from the pair of bead sections, and a tread section connected to the radially outer end of each of the sidewall sections 2. The tire has a carcass that extends in a toroidal shape across the pair of bead sections. The carcass is formed from carcass plies formed by covering carcass cords with rubber. The material used for the carcass cords is metal such as steel or organic fibers such as polyester. Sidewall rubber, which forms the outer surface of the sidewall section 2, is provided on the axially oriented side of the carcass.

[0011] <Sidewall section 2> Figure 1 shows a portion of the outer surface of the sidewall portion 2 as viewed from the outside in the tire axial direction, and is a view of the region between the mold split position Ps and the circumferential protrusion 23 as viewed from the outside in the tire axial direction. The tire's maximum width position (not shown) is the position where the profile surface PF of the sidewall portion 2 is furthest from the tire's equatorial plane in the tire axial direction. The profile surface PF is the surface that forms the basic contour of the sidewall portion 2, excluding protrusions such as ridges. The profile surface PF is formed by a smooth curved surface that is curved in a direction that is convex outward in the tire axial direction. The profile surface PF is composed of multiple curved surfaces when viewed in the tire meridian cross-section, and these multiple curved surfaces have different curvatures in the tire radial direction.

[0012] As shown in Figure 1, the mold splitting position Ps is located radially outward from the tire's maximum width position (not shown). The mold splitting position Ps is the boundary (splitting position) between the tread mold that forms the tread portion and the side mold that forms the sidewall portion 2. The mold splitting position Ps can also be identified by the parting line that forms on the outer surface of the sidewall portion 2. The parting line is a protruding mold mark that forms at the splitting position.

[0013] The rim line, which is not shown, is located radially inward of the tire's maximum width position (not shown). The rim line is formed by a projection extending in an annular shape along the tire's circumferential direction CD. The rim line is used to ensure that the bead portion is properly seated on the rim when the tire is mounted on the wheel. Although not shown in Figure 1, in this embodiment, three circumferential projections 21, 22, and 23, which protrude outward in the tire's axial direction, are arranged sequentially from the radially outer to the radially inner side of the tire between the mold split position Ps and the rim line.

[0014] Figure 2 shows the main part of Figure 1. Figure 3(A) is a cross-sectional view taken along the arrow AA in Figure 1, showing a cross-section along a direction perpendicular to the extension direction of the mark ridge 11 of the mark 1. In order to clearly illustrate the AA portion in Figure 1, the mark ridge 11 of the mark 1 through which the AA portion passes is omitted from the illustration. Figure 3(B) is a cross-sectional view taken along the arrow BB in Figure 2, showing a cross-section of the annular region BR having a smooth surface without a ridge. Figure 3(C) is a cross-sectional view taken along the arrow CC in Figure 2, showing a cross-section passing through the valley portion between the ridges 41 along a direction parallel to the extension direction of the ridge 41. Figure 3(D) is a cross-sectional view taken along the arrow DD in Figure 2, showing a cross-section along a direction intersecting the extension direction of the ridge 41. Figure 3(E) is a cross-sectional view taken along the arrow EE in Figure 2, showing a cross-section passing through the top of the ridge 41 along a direction parallel to the extension direction of the ridge 41.

[0015] As shown in Figures 1 and 2, in this tire, a strip-shaped annular region BR extending in the tire circumferential direction CD and a decorative region 4 are arranged on the outer surface of at least one of the pair of sidewall portions 2. As shown in Figure 3(B), the annular region BR includes a region having a smooth surface (profile surface PF in this embodiment) without ridges 41 (corresponding to the first undecorated region 3). As shown in Figures 1 and 2, the annular region BR is provided between circumferential protrusions 21 and 22. The annular region BR has a constant width and is formed in an annular shape extending over the entire circumference of the tire circumferential direction CD. The annular region BR is formed in a constant region in the tire radial direction, including the tire's maximum width position (not shown).

[0016] As shown in Figures 1 and 2, in this embodiment, the sidewall portion 2 has multiple decorative areas 4. As shown in Figure 2, the multiple decorative areas 4 include a first decorative area 4a which is the longest in the tire circumferential direction CD, a second decorative area 4b which is located radially outward of the first decorative area 4a, and a third decorative area 4c which is located radially inward of the first decorative area 4a. Each of the multiple decorative areas 4 is decorated with multiple ridges 41 and is formed in a strip shape extending in the tire circumferential direction CD. As shown in Figures 3(C), 3(D), and 3(E), each decorative area 4 is located in a recess 40 which is indented inward in the tire axial direction relative to the profile surface PF of the sidewall portion 2, with multiple ridges 41 protruding from the bottom of the recess 40. As shown in Figure 2, each of the multiple decorative areas 4 (first decorative area 4a, second decorative area 4b, third decorative area 4c) is surrounded by a first undecorated area 3.

[0017] As shown in FIG. 1, the annular region BR has a logo 1. The logo 1 is composed of characters, numbers, symbols, or graphics, etc., and displays information such as tire size, manufacturer name, variety, etc. On the other hand, the decorative region 4 is composed of decorative graphics, patterns, etc., and does not contain the above information. As shown in FIGS. 1 and 3(A), the logo 1 includes a region decorated with a plurality of logo ridges 11. The logo 1 includes a logo recess 10, and a plurality of logo ridges 11 are formed inside the logo recess 10. The top of the logo ridge 11 does not protrude beyond the profile surface PF, and the height of the logo ridge 11 is smaller than the depth of the logo recess 10. In the present embodiment, the logo ridges 11 extend parallel to the tire circumferential direction CD. The depth of the logo recess 10 may be, for example, 0.5 mm or more and 2.0 mm or less. The preferred depth of the logo recess 10 is 0.5 mm. The height of the logo ridge 11 may be, for example, 0.3 mm or more and 1.0 mm or less. The preferred height of the logo ridge 11 is 0.3 mm. As shown in FIG. 3(A), the apex angle θ1 of the logo ridge 11 in the cross-section passing through the plurality of logo ridges 11 is 90 degrees. The apex angle is the angle between a pair of straight lines appearing in the cross-section of the logo ridge 11 (the cross-section along the direction perpendicular to the extending direction of the logo ridge 11).

[0018] As shown in FIG. 1, the annular region BR has a first region AR1 where the logo 1 is formed and the decorative region 4 is not formed, and a second region AR2 where the logo 1 is not formed and the decorative region 4 is formed. The position of the first region AR1 in the tire circumferential direction CD is different from the position of the second region AR2 in the tire circumferential direction CD, and they do not overlap each other. That is, the logo 1 representing characters is arranged at a position separated from the decorative region 4 in the tire circumferential direction CD.

[0019] As shown in FIGS. 3(C), 3(D) and 3(E), the recess 40 has a depth D40 based on the profile surface PF. The ridge 41 protrudes outward in the tire axial direction from the bottom surface of the recess 40. By forming the decorative region 4 with the recess 40 and the ridge 41 protruding from the recess 40, it is easy to achieve the weight balance of the tire, and it is possible to suppress the generation of cracks compared with a convex decorative portion formed by raising a ridge from the profile surface PF. The plurality of ridges 41 are arranged at positions that are point-symmetrical about the tire axis C1 (see FIG. 1). In the present embodiment, the ridge 41 extends parallel to the tire radial direction. The extending direction of the logo ridge 11 and the extending direction of the ridge 41 constituting the decorative region 4 are different from each other.

[0020] The ridge 41 has a height H41 from the bottom to the top of the recess 40. The height H41 is set to be substantially constant along the extending direction of the ridge 41. The height H41 of the ridge 41 is larger than the depth D40 of the recess 40 (i.e., H41 > D40), and the difference between them corresponds to the protruding height Ph. The protruding height Ph is the height of the ridge 41 based on the profile surface PF. That is, the ridge 41 protrudes from the profile surface PF. As a result, an object that can cause a cut is more likely to hit the ridge 41 protruding from the profile surface PF first, so the profile surface PF is less likely to be damaged, and the impact resistance performance of the profile surface PF can be improved.

[0021] The protruding height Ph of the ridge 41, the depth D40 of the recess 40, and the height H41 of the ridge 41 in the plurality of decorative regions 4 are common. The depth D40 is, for example, 0.3 mm or more and 0.8 mm or less. On the condition that the ridge 41 is larger than the depth D40, the height H41 of the ridge 41 can be set, for example, in the range of 0.3 mm or more and 0.9 mm or less. The pitch W1 of the ridge 41 is, for example, 0.8 mm or more and 1.2 mm or less. The protruding height Ph is, for example, 0.05 mm or more and 1.0 mm or less. As an example, it can be exemplified that the depth D40 is 0.4 mm, the height H41 of the ridge 41 is 0.6 mm, and the pitch W1 of the ridge 41 is 0.8 mm. For example, if the depth D40 is 0.4 mm, the height H41 of the ridge 41 can be said to be 0.5 mm or more and 0.8 mm or less. As shown in Figure 3(D), the vertex angle θ2 of the ridge 41 in a cross-section passing through multiple ridges 41 is 60 degrees. The vertex angle is the angle between a pair of straight lines that appear in the cross-section of the ridge 41 (a cross-section along a direction perpendicular to the extension direction of the ridge 41). For example, the vertex angle θ2 of the ridge 41 can be set to be between 40 degrees and 80 degrees. By setting the vertex angle θ2 of the ridge 41 to be between 40 degrees and 80 degrees, the amount of light reflected from the line of sight parallel to the tire axis can be reduced, making the decorative area 4 appear darker and improving its aesthetics.

[0022] The vertex angle θ1 in the cross-section of the mark ridge 11 that constitutes mark 1 is different from the vertex angle θ2 in the cross-section of the ridge 41 that constitutes decorative area 4. As a result, one of mark 1 or decorative area 4 is brighter and more easily visible, allowing them to cooperate in improving each other's aesthetics.

[0023] In the embodiment shown in Figure 3(D), the bottom of the recess 40 has a plane 42 between the ridges 41 that is 20% or less of the pitch W1 of the ridges 41. That is, the dimension W2 of the plane 42 formed between the ridges 41 in the recess 40 is 20% or less of the pitch W1. By setting the dimension W2 of the plane 42 between the ridges 41 in this way, it is possible to reduce the area of ​​the plane 42 that is easily visible as bright, thereby suppressing the loss of the effect of making the decorative area 4 appear dark (obtained by the vertex angle θ2). Furthermore, it is possible to improve the durability of the ridges 41. Note that since the surface of the sidewall portion 2 is rounded, the plane 42 is a rounded smooth surface.

[0024] As shown in Figures 1 and 2, the sidewall portion 2 has a second undecorated area 5. Figure 4(F) is a cross-sectional view taken along the FF arrow in Figure 2, and is a cross-sectional view passing through the ridge 41 of the first undecorated area 3, the second undecorated area 5, and the decorated area 4. As shown in Figure 4(F), the second undecorated area 5 has a smooth surface that protrudes outward in the tire axial direction from the smooth surface of the first undecorated area 3. The protrusion height H51 of the second undecorated area 5 relative to the profile surface PF (first undecorated area 3) can be exemplified as 0.5 mm. The protrusion height H51 of the second undecorated area 5 is greater than the depth D40 of the decorated area 4. The protrusion height H51 of the second undecorated area 5 is 70% or more and 90% or less of the height H41 from the bottom of the recess 40 of the ridge 41. Note that the protrusion height H51 and the depth D40 may be the same, or the protrusion height H51 may be less than the depth D40.

[0025] As shown in Figure 2, the second region AR2 in the sidewall portion 2 is provided with a plurality (three in this embodiment) of second undecorated regions 5. The plurality of second undecorated regions 5 include a second undecorated region 5 adjacent to the inner side in the tire radial direction of the decorated region 4 (first decorated region 4a), a second undecorated region 5 adjacent to the inner side in the tire radial direction of the decorated region 4 (second decorated region 4b), and a second undecorated region 5 adjacent to the inner side in the tire radial direction of the decorated region 4 (first decorated region 4a) and adjacent to the outer side in the tire radial direction of the decorated region 4 (third decorated region 4c). In other words, the second undecorated region 5 is adjacent to the outer or inner side in the tire radial direction of the decorated region 4. This makes it possible to enhance contrast by arranging the second undecorated region 5, which appears brighter than the first undecorated region 3, adjacent to the outer or inner side in the tire radial direction of the decorated region 4.

[0026] As shown in Figures 2 and 6, the decorative area 4 has a first inward corner portion 43 where the edge of the decorative area 4 is concave toward the decorative area side. In this embodiment, three first inward corner portions 43 are provided in one second area AR2. The second undecorated area 5 is located in at least a portion of the first inward corner portion 43. In this embodiment, in one second area AR2, the three second undecorated areas 5 are each located in a portion of each of the three first inward corner portions 43. By arranging the second undecorated areas 5 in the first inward corner portions 43 of the decorative area 4, the contrast can be enhanced.

[0027] As shown in Figure 2, the second undecorated area 5 is located in each of the three regions (AR21, AR22, AR23) obtained by dividing the sidewall region between the ends P1 and P2 of the tire circumferential direction CD of the decorated area 4 into three equal parts along the tire circumferential direction CD. In each of the three regions (AR21, AR22, AR23), the area of ​​the second undecorated area 5 is 9% or more and 17% or less of the area of ​​the decorated area 4. The area referred to here is the area when projected onto a virtual plane perpendicular to the line of sight, viewed from a line of sight parallel to the tire axis. This area relationship allows for balancing the contrast enhancement effect. While it is preferable to satisfy this area relationship, it is not required.

[0028] Figure 5 is an enlarged view showing the first main part in Figure 2. As shown in Figure 5, the first undecorated area 3 in the sidewall portion 2 has a first portion 31 extending in the tire circumferential direction CD. In the embodiment shown in Figure 5, the first portion 31 extends parallel to the tire circumferential direction CD. The dimension L1 of the first portion 31 along the tire radial direction is constant. The decorated area 4 has a second portion 44a adjacent to the tire radially outer side of the first portion 31, and a third portion 44b adjacent to the tire radially inner side of the first portion 31. In the embodiment shown in Figure 5, the second portion 44a and the third portion 44b each extend in the tire circumferential direction CD. The dimension L2 of the second portion 44a along the tire radial direction is constant. The dimension L3 of the third portion 44b along the tire radial direction is constant. The dimension L1 of the first part 31 along the tire diameter direction is 20% or more and 50% or less of the total dimension L4 of the first part 31, second part 44a, and third part 44b along the tire diameter direction. The dimension L2 of the second part 44a along the tire diameter direction is 10% or more of the total dimension L4 of the first part 31, second part 44a, and third part 44b along the tire diameter direction. The dimension L3 of the third part 44b along the tire diameter direction is 10% or more of the total dimension L4 of the first part 31, second part 44a, and third part 44b along the tire diameter direction. As a result, the first undecorated area 3 is positioned between the decorated areas 4, and by using the above numerical relationship, the number of boundaries where the area changes when the line of sight moves along the tire diameter direction increases relatively, emphasizing the contrast between the dark, easily visible decorated area 4 and the bright, easily visible first undecorated area 3, thereby improving the aesthetic appearance.

[0029] Figure 6 is an enlarged view showing the second main part in Figure 2. Figure 4(G) is a cross-sectional view taken along the GG arrow in Figure 6, and is a cross-sectional view along the direction intersecting the extending direction of the ridge 41. Figure 4(H) is a cross-sectional view taken along the HH arrow in Figure 6, and is a cross-sectional view along the direction intersecting the extending direction of the ridge 41. Figure 4(J) is a cross-sectional view taken along the JJ arrow in Figure 6, and is a cross-sectional view along the direction intersecting the extending direction of the ridge 41. As shown in Figure 6, the multiple ridges 41 constituting the decorative area 4 are positioned point-symmetrically with respect to the tire axis C1. Therefore, the pitch W3 of the ridge 41 shown in Figure 4(G) is smaller than the pitch W4 of the ridge 41 shown in Figure 4(H) on the radially outer side of the tire than the part shown in Figure 4(G). Therefore, the area around the first edge 45a on the radially inner side of the decorative area 4 (first decorative area 4a) tends to appear darker than the area around the second edge 45b on the radially outer side of the decorative area 4. Therefore, the second undecorated area 5 is positioned adjacent to the decorated area 4 on the inner side in the tire radial direction. This places the dark-looking area around the first edge 45a adjacent to the bright-looking second undecorated area 5, thereby emphasizing the contrast and improving the aesthetic appearance.

[0030] As shown in Figure 6, the second undecorated area 5 is adjacent to the decorated area 4 (third decorated area 4c) on the radially outer side of the tire via the first boundary 51. In this case, the area around the first boundary 51 in the decorated area 4 appears brighter than the area on the radially outer side of the same decorated area 4, resulting in a difference in shade between the inner and outer sides of the same decorated area 4. Therefore, the first boundary 51 of the second undecorated area 5 is shaped to form a second recessed corner 5x that is recessed toward the second undecorated area. As the decorated area 4 (third decorated area 4c) extends into the second recessed corner 5x, the shadow of the second undecorated area 5, which protrudes more than the decorated area 4, may be projected onto the second recessed corner 5x. When the shadow of the second undecorated area 5 is projected onto the second recessed corner 5x, the second recessed corner 5x tends to appear darker compared to when no shadow is projected. Thus, this configuration makes it possible to reduce or suppress the contrast between the inner and outer sides in the radial direction of the tire within the same decorated area 4, thereby improving the aesthetic appearance.

[0031] [Differentiation] (A) In the above embodiment, the height of the trademark ridge 11 is less than the depth of the trademark recess 10, but is not limited thereto.

[0032] (B) In the above embodiment, the bottom of the recess 40 has a flat surface 42 between the ridges 41 that is 20% or less of the pitch W1 of the ridges 41, but is not limited to this. For example, the bottom of the recess 40 may not have a flat surface 42 between the ridges 41.

[0033] (C) In the above embodiment, the extending direction of the ridge 41 of the decorative area 4 and the extending direction of the emblem ridge 11 are different, but they may be the same.

[0034] (D) In ​​the above embodiment, the extension direction of the ridge 41 of the decorative region 4 is parallel to the tire radial direction, but is not limited thereto. For example, the extension direction of the ridge 41 of the decorative region 4 can be changed in various ways, as long as it is not parallel to the tire circumferential direction CD, but inclined with respect to the tire circumferential direction CD. Furthermore, in the above embodiment, the extension direction of the marking ridge 11 is parallel to the tire circumferential direction CD, but is not limited to this. It can be changed as appropriate.

[0035] (E) In the above embodiment, the first part 31 divides the second part 44a and the third part 44b, and the decorative region 4 including the second part 44a (second decorative region 4b) and the decorative region 4 including the third part 44b (first decorative region 4a) are separated, but the embodiment is not limited to this. For example, the first part 31 does not have to divide the decorative region 4, and the first part 31 may be an L-shaped first undecorated region 3 that enters one of the decorative regions 4.

[0036] (E) In the above embodiment, the vertex angle θ1 of the mark ridge 11 is 90 degrees, but is not limited to this.

[0037] (F) In the above embodiment, the first portion 31 extends parallel to the tire circumferential direction CD, but is not limited thereto. For example, the extension direction of the first portion 31 can be changed as long as the dimensions along the tire radial direction are constant. In the above embodiment, the second portion 44a extends parallel to the tire circumferential direction CD, but is not limited thereto. For example, the extension direction of the second portion 44a can be changed as long as its dimensions along the tire radial direction are constant. In the above embodiment, the third portion 44b extends parallel to the tire circumferential direction CD, but is not limited thereto. For example, the extension direction of the third portion 44b can be changed as long as the dimensions along the tire radial direction are constant.

[0038] Those skilled in the art will understand that the embodiments described above are specific examples of the following embodiments.

[0039] [1] As in the above embodiment, the pneumatic tire may have a sidewall portion having a first undecorated region having a smooth surface and a decorated region adjacent to the first undecorated region and decorated with a plurality of ridges, wherein the decorated region has a recess that is indented from the smooth surface, the plurality of ridges protrude from the bottom of the recess, the protruding height of the plurality of ridges is greater than the depth of the recess, and the apex angle of the ridges in a cross section passing through the plurality of ridges is 40 degrees or more and 80 degrees or less. By setting the ridge apex angle in this way, it is possible to reduce the amount of light reflected towards the line of sight parallel to the tire axis, making the decorative area appear darker and improving its aesthetics.

[0040] [2] The pneumatic tire described in [1] above, wherein the bottom of the recess may have a flat surface between the ridges that is 20% or less of the pitch of the ridges, or it may not have a flat surface between the ridges. As in this configuration, by eliminating planes between the ridges at the bottom of the decorative area, or by having planes whose dimensions are 20% or less of the ridge pitch, it is possible to reduce the number of planes that tend to appear brighter, thereby mitigating the effect of making the decorative area appear darker. Furthermore, the durability of the ridges can also be improved.

[0041] [3] The pneumatic tire described in [1] or [2] above, wherein the sidewall portion further comprises a second undecorated region having a smooth surface that protrudes outward in the tire axial direction from the smooth surface of the first undecorated region, and the second undecorated region is adjacent to the outer or inner side in the tire radial direction of the decorated region. In this way, by placing a second undecorated area, which appears even brighter than the undecorated area, on the outer or inner side of the decorated area in the tire radial direction, the contrast can be enhanced, and the aesthetic appearance can be improved.

[0042] [4] The pneumatic tire described in [3] above, wherein each ridge of the decorative region extends at an inclination with respect to the circumferential direction of the tire, each ridge of the decorative region is positioned at a point-symmetric position with respect to the tire axis, and the second undecorated region is adjacent to the inside of the decorative region in the radial direction of the tire. Thus, since each ridge is arranged point-symmetrically with respect to the tire axis, the pitch of the ridges on the inner side in the radial direction of the tire within the decorative area is shorter than the pitch of the ridges on the outer side in the radial direction of the tire within the decorative area, making it appear darker. By placing the darker-looking area adjacent to the brighter-looking second undecorated area, the contrast can be enhanced.

[0043] [5] A pneumatic tire according to any of the above [3] to [4], wherein the decorative area has a first inward corner portion where the edge of the decorative area is concave toward the decorative area, and the second undecorated area is located in at least a portion of the first inward corner portion. By placing a second undecorated area in the first inner corner of a decorative area, the contrast can be enhanced.

[0044] [6] A pneumatic tire according to any of [3] to [5] above, wherein each ridge of the decorative region extends inclined with respect to the tire circumferential direction, each ridge of the decorative region is positioned in a point-symmetric position with respect to the tire axis, the second undecorated region is adjacent to the radially outer side of the decorative region via a first boundary, and the first boundary forms a second inward corner that is recessed toward the second undecorated region. Since each ridge is arranged point-symmetrically with respect to the tire axis, the pitch of the ridges on the outer side in the radial direction of the tire within the decorative area is longer than the pitch of the ridges on the inner side in the radial direction of the tire within the decorative area, making it appear brighter. By placing the brighter-looking area adjacent to the second undecorated area via the first interface, and further forming a second recessed corner where the first interface is recessed into the second undecorated area, the shadow of the second undecorated area is projected onto the decorative area located in the second recessed corner, making the decorative area appear darker and thus enhancing the contrast.

[0045] [7] A pneumatic tire according to any of the above [3] to [6], wherein the second undecorated region is located in each of the three regions obtained by dividing the sidewall region between the two ends of the decorated region in the tire circumferential direction into three equal parts in the tire circumferential direction. This configuration allows for a balance in the contrast enhancement effect.

[0046] [8] A pneumatic tire as described in any of [1] to [7] above, wherein the first undecorated region has a first portion extending in the circumferential direction of the tire, the decorated region has a second portion and a third portion, the second portion is adjacent to the radially outer side of the first portion, the third portion is adjacent to the radially inner side of the first portion, the dimension of the first portion along the tire radial direction is 20% or more and 50% or less of the total dimension of the first portion, the second portion and the third portion along the tire radial direction, and the respective dimensions of the second portion and the third portion along the tire radial direction are 10% or more of the total dimension of the first portion, the second portion and the third portion along the tire radial direction. With this configuration, a first undecorated area is placed between the decorated areas, and by using the above numerical relationship, the number of boundaries where the area changes when the gaze moves along the tire diameter direction increases relatively. This emphasizes the contrast between the dark, easily visible decorated area and the bright, easily visible first undecorated area, thereby improving the aesthetic appearance.

[0047] [9] A pneumatic tire according to any of the above [1] to [8] may be provided, wherein the sidewall portion has a mark at a position spaced apart from the decorative area in the circumferential direction of the tire, and the mark has an area decorated with a plurality of mark ridges.

[0048]

[10] The pneumatic tire described in [9] above may be such that the vertex angle in the cross-section of the decorative region ridge is different from the vertex angle in the cross-section of the mark ridge. This allows either the emblem or the decorative area to be brighter and more easily visible, thus enabling them to work together to enhance each other's aesthetic appeal.

[0049] Although embodiments of this disclosure have been described above with reference to the drawings, it should be understood that the specific configurations are not limited to these embodiments. The scope of this disclosure is indicated not only by the description of the embodiments above but also by the claims, and further includes all modifications within the meaning and scope equivalent to the claims.

[0050] The structures adopted in each of the above embodiments can be adopted in any other embodiment. The specific configuration of each part is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of this disclosure. [Explanation of symbols]

[0051] 1 :Mark 2: Sidewall section 3: First undecorated area 4: Decorative area 5: Second undecorated area 5x: Second inner corner 11: Mark Ridge 31: Part 1 40: Recess 41: Ridge 42: Plane 43: First inner corner 44a: 2nd part 44b: 3rd part 51 :1st boundary CD: Tire circumferential direction

Claims

1. The sidewall portion comprises a first undecorated region having a smooth surface, and a decorated region adjacent to the first undecorated region and decorated with a plurality of ridges. The decorative region has a recessed area relative to the smooth surface, the plurality of ridges protrude from the bottom of the recess, and the protruding height of the plurality of ridges is greater than the depth of the recess. A pneumatic tire in which, in a cross-section passing through the plurality of ridges, the vertex angles of the ridges are 40 degrees or more and 80 degrees or less.

2. The pneumatic tire according to claim 1, wherein the bottom of the recess has a flat surface between the ridges that is 20% or less of the pitch of the ridges, or does not have a flat surface between the ridges.

3. The sidewall portion further comprises a second undecorated region having a smooth surface that protrudes outward in the tire axial direction from the smooth surface of the first undecorated region. The pneumatic tire according to claim 1, wherein the second undecorated region is adjacent to the radially outer or inner side of the decorated region.

4. Each ridge of the decorative region extends at an inclination with respect to the tire circumferential direction, and each ridge of the decorative region is positioned in a point-symmetrical position with respect to the tire axis. The pneumatic tire according to claim 3, wherein the second undecorated region is adjacent to the radially inward side of the decorated region.

5. The decorative region has a first inner corner portion where the edge of the decorative region is concave toward the decorative region side. The pneumatic tire according to claim 3, wherein the second undecorated region is located in at least a portion of the first inner corner.

6. Each ridge of the decorative region extends at an inclination with respect to the tire circumferential direction, and each ridge of the decorative region is positioned in a point-symmetrical position with respect to the tire axis. The second undecorated region is adjacent to the decorated region on the radially outer side of the tire via a first boundary. The pneumatic tire according to claim 3, wherein the first boundary forms a second recessed corner portion that is recessed toward the second undecorated region.

7. The pneumatic tire according to claim 3, wherein the second undecorated region is located in each of the three regions obtained by dividing the sidewall region between the two ends of the decorated region in the tire circumferential direction into three equal parts in the tire circumferential direction.

8. The first undecorated region has a first portion that extends in the circumferential direction of the tire, The decorative region has a second portion and a third portion, the second portion being adjacent to the outer side of the first portion in the tire radial direction, and the third portion being adjacent to the inner side of the first portion in the tire radial direction. The dimension of the first part along the tire radial direction is 20% or more and 50% or less of the total dimension of the first part, the second part and the third part along the tire radial direction. The pneumatic tire according to claim 1, wherein the dimensions of the second portion and the third portion along the tire radial direction are 10% or more of the total dimensions of the first portion, the second portion and the third portion along the tire radial direction.

9. The sidewall portion has a mark at a position spaced apart from the decorative area in the circumferential direction of the tire. The pneumatic tire according to claim 1, wherein the mark has an area decorated with a plurality of mark ridges.

10. The pneumatic tire according to claim 9, wherein the vertex angle in the cross-section of the ridge of the decorative region and the vertex angle in the cross-section of the mark ridge are different.

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