tire

Abstract

To provide a tire capable of improving a blackening performance and a performance of making a visual angle uniform of a ridge region.SOLUTION: A tire includes, on a tire side surface, a ridge region 5 including an array of a plurality of ridge units U (UA to UD). Each of the plurality of ridge units U includes a first ridge 52 having an annular structure or a cutout annular structure having a cutout part in a part thereof and a second ridge 53 extending along an inner periphery of the first ridge 52 in plan view of the tire side surface. The first ridge 52 is formed by connecting two or more annular projections 521a to 521c radially projecting from a ridge center and at least one annular recess 522a to 522c recessed toward the ridge center.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a tire, and more particularly to a tire capable of improving the blackening performance and viewing angle uniformity performance of a ridge region.

Background Art

[0002] In recent tires, a configuration has been adopted in which a logo such as a side brand is blackened using a ridge region composed of a plurality of ridges to improve the visibility of the logo. As a conventional tire adopting such a configuration, the technique described in Patent Document 1 is known. On the other hand, there is also a problem that the blackening effect of the ridge region when the tire side surface is viewed from different directions should be made uniform. As a conventional tire regarding such a problem, the technique described in Patent Document 2 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a tire capable of improving the blackening performance and viewing angle uniformity performance of a ridge region.

Means for Solving the Problems

[0005] In order to achieve the above object, a tire according to the present invention is a tire provided with a ridge region formed by arranging a plurality of ridge units on a tire side surface, wherein each of the plurality of ridge units has, in a plan view of the tire side surface, a first ridge having an annular structure or a notched annular structure having a notch in part, and a second ridge extending along an inner circumference of the first ridge, and the first ridge is characterized by being formed by connecting two or more annular convex portions protruding radially from a ridge center and at least one annular concave portion recessing toward the ridge center.

Advantages of the Invention

[0006] In the tire according to the present invention, (1) since the tire side surface is provided with a ridge region formed by arranging a plurality of ridge units, in a plan view of the tire side portion, the light absorption rate in the ridge region becomes relatively larger than the light absorption rate in other regions. As a result, the ridge region is relatively blackened, and the contrast of the tire side surface becomes clear. Also, (2) since the first ridge has two or more annular convex portions, the irregular reflection action of light between the ridges is promoted, and the viewing angle uniformity of the ridge region, that is, the uniformity of the blackening action of the ridge region when the tire side surface is viewed from different directions, is improved. Also, (3) since the first ridge has at least one annular concave portion, the peripheral length of the first ridge increases, and the blackening action of the ridge region is improved. Further, (4) since the second ridge extends along the inner circumference of the curved first ridge, the light absorption rate and the irregular reflection action between the first ridge and the second ridge are promoted. Due to these, there is an advantage that the visibility of the tire side surface is improved.

Brief Description of the Drawings

[0007]

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Embodiments for Carrying Out the Invention

[0008] Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited by this embodiment. Also, the components of this embodiment include those that can be replaced and are self-evidently replaceable while maintaining the identity of the invention. Further, a plurality of modifications described in this embodiment can be arbitrarily combined within the scope self-evident to those skilled in the art.

[0009] [Tire] FIG. 1 is a cross-sectional view in the tire meridian direction showing a tire 1 according to an embodiment of the present invention. The figure shows a cross-sectional view of one-side region in the tire radial direction of the tire 1 mounted on a rim 20. In this embodiment, as an example of the tire, a pneumatic radial tire for a passenger car will be described.

[0010] In the figure, the cross-section in the tire meridian direction is defined as the cross-section when the tire is cut by a plane including the tire rotation axis (not shown). Also, the tire equatorial plane CL is defined as a plane passing through the midpoint of the tire cross-sectional width defined by JATMA and perpendicular to the tire rotation axis. Also, the tire width direction is defined as the direction parallel to the tire rotation axis, and the tire radial direction is defined as the direction perpendicular to the tire rotation axis. Further, point T is the tire ground end, and point Ac is the tire maximum width position.

[0011] The tire 1 has an annular structure centered on the tire rotation axis, and includes a pair of bead cores 11, 11, a pair of bead fillers 12, 12, a carcass layer 13, a belt layer 14, a tread rubber 15, a pair of sidewall rubbers 16, 16, and a pair of rim cushion rubbers 17, 17 (see FIG. 1).

[0012] The pair of bead cores 11, 11 are formed by winding one or a plurality of bead wires made of steel in an annular and multiple manner, and are embedded in the bead portion to form the cores of the left and right bead portions. The pair of bead fillers 12, 12 are respectively disposed on the outer periphery in the tire radial direction of the pair of bead cores 11, 11 to reinforce the bead portion.

[0013] The carcass layer 13 has a single-layer structure composed of one carcass ply or a multi-layer structure formed by laminating a plurality of carcass plies, and is bridged in a toroidal shape between the left and right bead cores 11, 11 to constitute the skeleton of the tire. Further, both ends of the carcass layer 13 are wound back and locked outward in the tire width direction so as to wrap the bead core 11 and the bead filler 12. Further, the carcass ply of the carcass layer 13 is formed by covering a plurality of carcass cords made of steel or an organic fiber material (for example, aramid, nylon, polyester, rayon, etc.) with a coating rubber and rolling, and has a cord angle of 80° or more and 100° or less (defined as the inclination angle of the longitudinal direction of the carcass cord with respect to the tire circumferential direction).

[0014] The belt layer 14 is formed by laminating a plurality of belt plies 141 to 143, and is disposed so as to be wound around the outer circumference of the carcass layer 13. The belt plies 141 to 143 include a pair of intersecting belts 141, 142 and a belt cover 143.

[0015] The pair of intersecting belts 141, 142 are formed by covering a plurality of belt cords made of steel or an organic fiber material with a coating rubber and rolling, and have a cord angle of 15° or more and 55° or less in absolute value (defined as the inclination angle of the longitudinal direction of the belt cord with respect to the tire circumferential direction). Further, the pair of intersecting belts 141, 142 have cord angles of opposite signs to each other, and are laminated with the longitudinal directions of the belt cords intersecting each other (so-called cross ply structure). Further, the pair of intersecting belts 141, 142 are laminated and disposed on the outer side in the tire radial direction of the carcass layer 13.

[0016] The belt cover 143 is formed by coating a belt cover cord made of steel or organic fiber material with a coating rubber, and has a cord angle of 0° or more and 10° or less in absolute value. Further, the belt cover 143 is, for example, a strip material formed by coating one or a plurality of belt cover cords with a coating rubber, and this strip material is wound around the outer peripheral surfaces of the crossed belts 141 and 142 a plurality of times and spirally in the tire circumferential direction. Further, the belt cover 143 is arranged to cover the entire area of the crossed belts 141 and 142.

[0017] The tread rubber 15 is arranged on the outer periphery in the tire radial direction of the carcass layer 13 and the belt layer 14 to constitute the tread portion of the tire 1. Further, the tread rubber 15 is made of a rubber material excellent in grounding characteristics and weather resistance, and is exposed over the entire area of the tire outer peripheral surface to constitute a tread surface. The pair of sidewall rubbers 16, 16 are respectively arranged on the outer sides in the tire width direction of the carcass layer 13 to constitute the left and right sidewall portions. The pair of rim cushion rubbers 17, 17 extend from the inner side in the tire radial direction to the outer side in the tire width direction of the left and right bead cores 11, 11 and the turned-back portion of the carcass layer 13 to constitute the rim fitting surface of the bead portion.

[0018] [Tire side portion] FIG. 2 is a plan view showing the tire side portion of the tire described in FIG. 1. FIG. 3 is an enlarged view showing the emblem portion 2 of the tire side portion described in FIG. 2. In these figures, FIG. 2 shows a plan view of the tire 1 viewed from the axial direction, and FIG. 3 shows a part of the emblem portion 2.

[0019] As shown in FIG. 2, the tire 1 includes an emblem portion 2 and a peripheral region 3 in the tire side portion.

[0020] The emblem part 2 includes emblems composed of characters, figures or symbols, or combinations thereof, and in particular includes trademarks that function as identification marks indicating tire manufacturers, tire brands, etc. Also, a plurality of emblem parts 2, 2 are arranged spaced apart in the tire circumferential direction. For example, in the configuration of FIG. 2, an emblem composed of a combination of the character string "YOKOHAMA" indicating the tire manufacturer and a logo in which the first letter "Y" is designed is engraved on the surface of the tire side part. Also, a pair of emblem parts 2, 2 are arranged at opposing positions in the tire circumferential direction.

[0021] Also, in FIG. 3, the radial height H2 of the elements 21A to 21E constituting the emblem part 2 is in the range of 0.05 ≦ H2 / SH ≦ 0.80 with respect to the tire cross-sectional height SH, preferably in the range of 0.10 ≦ H2 / SH ≦ 0.70. Thereby, the visibility of the emblem part 2 is improved.

[0022] The radial height H2 of the elements 21A to 21E is measured as the maximum value of the extension lengths of the elements 21A to 21E in the tire radial direction.

[0023] The tire cross-sectional height SH is a distance of 1 / 2 of the difference between the tire outer diameter and the rim diameter, and is measured with the tire mounted on a specified rim, applying a specified internal pressure and in a non-loaded state.

[0024] The specified rim refers to the "Applicable Rim" defined in JATMA, the "Design Rim" defined in TRA, or the "Measuring Rim" defined in ETRTO. Also, the specified internal pressure refers to the "Maximum Air Pressure" defined in JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" defined in TRA, or the "INFLATION PRESSURES" defined in ETRTO. Further, the specified load refers to the "Maximum Load Capacity" defined in JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" defined in TRA, or the "LOAD CAPACITY" defined in ETRTO. However, in JATMA, in the case of passenger car tires, the specified internal pressure is 180 [kPa] of air pressure, and the specified load is 88 [%] of the maximum load capacity.

[0025] The peripheral region 3 is a region surrounding the emblem part 2 and is formed on the surface of the tire side part. This peripheral region 3 may be a smooth surface having a smooth surface or a concavo-convex surface subjected to surface treatment.

[0026] For example, in the configuration of FIG. 2, the peripheral region 3 is a smooth surface and has a continuous smooth surface without grooves or uneven portions. Also, since the peripheral region 3 is arranged to surround the entire emblem part 2, the visibility of the emblem part 2 is enhanced. Further, since the peripheral region 3 is formed between a pair of thin ribs 41, 42 extending in the tire circumferential direction, the designability of the tire side part is enhanced. Also, since a single peripheral region 3 has an annular structure extending over the entire circumference of the tire side part, it surrounds the pair of emblem parts 2, 2.

[0027] In addition, in the configuration of FIG. 2, the logo portion 2 and the peripheral region 3 are arranged on the outer side in the tire radial direction with respect to the tire maximum width position Ac. More specifically, in the region from the tire ground contact end T to the tire maximum width position Ac (see FIG. 1), a pair of thin ribs 41, 42 extending in the tire circumferential direction are arranged, and the logo portion 2 and the peripheral region 3 are arranged between these thin ribs 41, 42. Thereby, the visibility of the logo portion 2 is enhanced. However, it is not limited to this, and the logo portion 2 and the peripheral region 3 may be arranged to intersect the tire maximum width position Ac, or may be arranged on the inner side in the tire radial direction with respect to the tire maximum width position Ac (not shown).

[0028] The tire maximum width position Ac is defined as the maximum width position of the tire cross-sectional width.

[0029] The tire cross-sectional width is measured as the straight-line distance between the sidewalls excluding patterns, letters, etc. on the tire side surface when the tire is mounted on a specified rim, a specified internal pressure is applied, and it is in an unloaded state.

[0030] The tire ground contact end T is defined as the maximum width position in the tire axial direction on the contact surface between the tire and the flat plate when the tire is mounted on a specified rim, a specified internal pressure is applied, and a load corresponding to a specified load is applied while being placed perpendicular to the flat plate in a stationary state.

[0031] Note that the above-mentioned pair of thin ribs 41, 42 have a width of 0.4 [mm] or more and 0.8 [mm] or less and a height of 0.1 [mm] or more and 1.0 [mm] or less, and function as a discharge path for residual air during tire vulcanization molding. Thereby, the occurrence of vulcanization failure in the logo portion 2 and the peripheral region 3 is suppressed. Also, in the configuration of FIG. 2, the thin rib 41 on the outer diameter side is at the split position of the mold of the tire molding die.

[0032] Further, in FIG. 3, the radial height H2 [mm] of the elements 21A to 21E constituting the emblem portion 2 is in the range of 0.30 ≦ H2 / H4 ≦ 0.80 with respect to the arrangement interval H4 [mm] of the thin ribs 41 and 42 in the tire radial direction, preferably in the range of 0.40 ≦ H2 / H4 ≦ 0.70. Also, as shown in FIG. 3, the emblem portion 2 is preferably arranged spaced apart from the pair of thin ribs 41 and 42. Thereby, the visibility of the emblem portion 2 is enhanced.

[0033] [Ridge region] FIGS. 4 to 7 are explanatory views showing the ridge region 5 of the tire side portion described in FIG. 2. In these figures, FIG. 4 shows one element 21A constituting the emblem portion 2 described in FIG. 3, FIG. 5 is an enlarged plan view showing a part of the ridge region 5 described in FIG. 4, FIG. 6 is an enlarged view showing the single ridge unit U (UA to UD) described in FIG. 5, and FIG. 7 is a cross-sectional view taken along line A showing the ridge unit U described in FIG. 6. Here, as an example, a configuration in which the emblem portion 2 is composed of the ridge region 5 will be described.

[0034] As shown in FIG. 7, the ridge region 5 is composed of a housing 51 and first and second ridges 52 and 53.

[0035] The housing 51 is a frame-shaped recess formed on the tire side surface and forms the contour line of the emblem portion 2 in a plan view of the tire side portion. Also, the depth H51 (see FIG. 7) of the housing 51 is in the range of 0.10 [mm] ≦ H51 ≦ 3.00 [mm], preferably in the range of 0.20 [mm] ≦ H51 ≦ 1.50 [mm].

[0036] The depth H51 of the housing 51 is defined as the distance from the edge portion of the housing 51 (in FIG. 7, the surface of the peripheral region 3) to the bottom surface of the housing 51.

[0037] The first and second ridges 52 and 53 are rib-shaped convex portions protruding from the bottom surface of the housing 51, and have a cross-sectional shape with a width narrowing toward the top. Also, as shown in FIG. 5, a plurality of ridge units U formed by the first and second ridges 52 and 53 are arranged in a predetermined direction and filled in the housing 51. The planar shape and arrangement pattern of the ridge unit U will be described in detail later.

[0038] For example, in the configuration of FIG. 3, as shown in FIG. 4, the emblem portion 2 is formed by the ridge region 5. Specifically, the logo 2A constituting the emblem portion 2 is composed of a combination of a plurality of parallel thin lines. Also, the contour lines of these thin lines are formed by the edge portion of the housing 51 (see FIG. 7) described later. Similarly, other components constituting the emblem portion 2 (for example, elements 21B to 21E in FIG. 3) are composed of thick lines indicating characters, and the contour lines of the thick lines are formed by the edge portion of the housing 51 (not shown). Also, as shown in FIG. 7, the first and second ridges 52 and 53 have a trapezoidal or triangular uniform cross-section. And a plurality of ridge units U formed by the first and second ridges 52 and 53 are arranged in a predetermined arrangement pattern in the housing 51 and filled over the entire area of the housing 51. Thereby, the emblem of the emblem portion 2 is presented by the housing 51 and the ridge unit U.

[0039] In the above configuration, since the tire side surface includes the ridge region 5 formed by arranging a plurality of ridge units U, in a plan view of the tire side portion, the light absorption rate in the ridge region 5 (the emblem portion 2 in FIG. 3) is relatively larger than the light absorption rate in other regions (the peripheral region 3 in FIG. 3). As a result, the ridge region 5 is relatively blackened, the contrast of the tire side surface becomes clear, and the visibility of the tire side surface is improved.

[0040] In the configuration of FIG. 7, the heights H52 and H53 of the first and second ridges 52 and 53 are in the range of 0.30 ≦ H52 / H51 < 1.00 and 0.30 ≦ H53 / H51 < 1.00 with respect to the depth H51 of the housing 51, preferably in the range of 0.50 ≦ H52 / H51 ≦ 0.95 and 0.50 ≦ H53 / H51 ≦ 0.95. Therefore, the tops of the first and second ridges 52 and 53 are embedded in the housing 51. In such a configuration, it is preferable in that the deterioration of the air resistance of the tire side portion due to the ridges 52 and 53 protruding from the tire side surface is suppressed. However, not limited to this, when the heights H52 and H53 of the ridges 52 and 53 are in the range of 1.00 ≦ H52 / H51 and 1.00 ≦ H53 / H51 with respect to the depth H51 of the housing 51, the ridges 52 and 53 may protrude from the tire side surface (not shown). In such a configuration, when wax is applied to the tire side surface, the wax is easily applied to the tops of the ridges 52 and 53, and the retention of the wax on the tire side surface is improved.

[0041] As shown in FIG. 7, the heights H52 and H53 of the ridges 52 and 53 are defined as the distance from the tops of the ridges 52 and 53 to the bottom surface of the housing 51. Specifically, they are measured as the distance from the tops of the ridges 52 and 53 to the bottom of the valley between the adjacent ridges 52, 52; 52, 53.

[0042] Also, in FIG. 7, the widths W52A and W53A of the tops of the ridges 52 and 53 are in the range of 0 ≦ W52A / W52B ≦ 0.90 and 0 ≦ W53A / W53B ≦ 0.90 with respect to the widths W52B and W53B of the bases of the ridges 52 and 53, preferably in the range of 0.10 ≦ W52A / W52B ≦ 0.70 and 0.10 ≦ W53A / W53B ≦ 0.70. The lower limit suppresses the deterioration of the workability of the ridges 52 and 53 due to the tops of the ridges 52 and 53 being too thin, and the upper limit improves the blackening effect of the tire side surface by the ridges 52 and 53.

[0043] The widths W52A, W52B, W53A, and W53B of the ridges 52 and 53 are measured as the widths in a cross-section perpendicular to the longitudinal direction of the ridges 52 and 53. Further, the widths W52B and W53B of the bases of the ridges 52 and 53 are defined as the widths of the bottom surfaces of the ridges 52 and 53 (in FIG. 7, the contact surfaces between the bases of the ridges 52 and 53 and the bottom surface of the housing 51), and specifically, are measured as the distances of virtual lines connecting the bottom valleys between adjacent ridges 52, 52; 52, 53.

[0044] In addition, in the configuration of FIG. 2, as described above, the ridge region 5 is composed of the housing 51 and the first and second ridges 52 and 53 arranged in the housing 51 (see FIGS. 5 and 7). However, it is not limited to this, and the housing 51 may be omitted, and the ridge region 5 may be composed of only the first and second ridges 52 and 53 (not shown). For example, the first and second ridges 52 and 53 may protrude from the same plane as the peripheral region 3. Even with such a configuration, the visibility of the emblem portion 2 can be improved.

[0045] Also, in the configuration of FIG. 2, the peripheral region 3 is a smooth surface having a smooth surface. Such a configuration is preferable in that the visibility of the emblem portion 2 composed of the housing 51 and the first and second ridges 52 and 53 is improved. However, it is not limited to this, and the peripheral region 3 may be a concavo-convex surface having a surface treatment (not shown). The concavo-convex surface having a surface treatment may be configured by arranging a plurality of arranged concavo-convex portions, for example, a plurality of ridges or grooves having a longitudinal shape, or may be configured by arranging a plurality of protrusions or depressions having a hemispherical shape or a conical shape.

[0046] [Planar shape of the ridge] As shown in FIG. 5, the ridge region 5 includes a plurality of ridge units U (UA to UD). The figure shows four mutually adjacent ridge units U. In the ridge region 5, a large number of ridge units U are repeatedly arranged in a predetermined arrangement pattern in the planar direction of the tire side portion.

[0047] The ridge unit U, i.e., the ridge per unit that forms the motif of the ridge region 5, consists of first and second ridges 52 and 53. Further, the first and second ridges 52 and 53 have an annular structure (see FIG. 6) or a notched annular structure (not shown) having a notch in part, in a plan view of the tire side surface.

[0048] The annular structure of the ridges 52 and 53 is a structure formed by connecting both ends that are linear or longitudinal in a plan view, and is not limited to a complete annulus, but includes a substantial annulus having a minute separation of less than 0.50 [mm], preferably less than 0.40 [mm]. On the other hand, the notched annular structure of the ridges 52 and 53 is a structure formed by notching a part of the above-described annular structure with a notch, and the lower limit of the separation distance (not shown) of the ends of the ridges 52 and 53 notched by the notch is in the range of 0.50 [mm] or more, preferably 2.00 [mm] or more. Further, the upper limit of the separation distance of the ends of the ridges 52 and 53 notched by the notch is in the range of 50 [%] or less, preferably 40 [%] or less, with respect to the outer diameter Rm of the minimum circumscribing circle M. Also, it is preferable that the notched annular structure has a single notch. Thereby, the arrangement density of the ridges 52 and 53 in the ridge region 5 is ensured, and the blackening action of the ridge region 5 is ensured.

[0049] Also, as shown in FIG. 6, the ridge unit U consists of a combination of a first ridge 52 and a second ridge 53.

[0050] The first ridge 52 is formed by connecting two or more annular convex portions 521a to 521c and at least one annular concave portion 522a to 522c.

[0051] The annular convex portions 521a to 521c have a smoothly curved arch shape. Specifically, as shown in FIG. 6, a part of the first ridge 52 having the above-described annular structure or notched annular structure bulges in a direction away from the ridge center O, thereby forming the annular convex portions 521a to 521c. In such a configuration, the diffuse reflection effect of light between the ridges is promoted, and the viewing angle uniformity of the ridge region 5, that is, the uniformity of the blackening effect of the ridge region 5 in different direction views, is improved. Thereby, the visibility of the tire side surface is improved.

[0052] Also, as shown in FIG. 6, the annular convex portions 521a to 521c have a widened portion (reference numerals in the figure are omitted) that widens from the ridge center O toward the maximum protruding position. For this reason, the annular convex portions 521a to 521c have a constricted portion between the ridge center O and the maximum protruding position, and also have an end portion that bulges in an arc shape toward the protruding side. Further, the maximum width D21 of the annular convex portions 521a to 521c is in the range of 0.30 [mm] ≤ D21 ≤ 5.00 [mm], preferably in the range of 0.50 [mm] ≤ D21 ≤ 4.00 [mm]. In such a configuration, compared with a configuration in which a pair of ridge portions constituting each of the annular convex portions 521a to 521c extend with a certain separation distance (not shown), the peripheral length of the curved portion in the annular convex portions 521a to 521c increases, the blackening effect of the ridge region 5 is improved, and the viewing angle uniformity of the ridge region 5 is improved.

[0053] The maximum width D21 of the annular convex portions 521a to 521c is measured as the maximum value of the width in a direction perpendicular to the protruding direction of the annular convex portions 521a to 521c.

[0054] In addition, three or more annular convex portions 521a to 521c protrude radially from the ridge center O, that is, in mutually different directions. Further, the three or more annular convex portions 521a to 521c are arranged at predetermined circumferential intervals θa to θc. At this time, the ratio of the maximum value to the minimum value of the circumferential intervals θa to θc of the annular convex portions 521a to 521c is in the range of 1.00 or more and 1.50 or less, preferably in the range of 1.00 or more and 1.30 or less. Thereby, the protruding directions of the annular convex portions 521a to 521c are dispersed, and the viewing angle uniformity of the ridge region 5 is improved.

[0055] The ridge center O is defined as the center of the smallest circle that includes the first ridge 52, that is, the center of the minimum circumscribing circle M.

[0056] The circumferential intervals θa to θc of the annular convex portions 521a to 521c are defined as the angles formed by the virtual straight lines passing through the ridge center O and the maximum protruding positions of the annular convex portions 521a to 521c.

[0057] In addition, the outer diameter Rm of the minimum circumscribing circle M is in the range of 0.80 [mm] ≤ Rm ≤ 20.00 [mm], preferably in the range of 1.00 [mm] ≤ Rm ≤ 10.00 [mm].

[0058] The annular concave portions 522a to 522c have a shape that is recessed toward the ridge center O and are arranged between adjacent annular convex portions 521a, 321b; 321b, 321c; 521c, 321a. Specifically, as shown in FIG. 6, the annular concave portions 522a to 522c are formed so as to be recessed with respect to the tangents that are in contact with adjacent annular convex portions 521a, 321b; 321b, 321c; 521c, 321a. Further, the annular concave portions 522a to 522c have a smoothly curved arch shape. With such a configuration, since the first ridge 52 has at least one annular concave portion 522a to 522c, the peripheral length of the first ridge 52 increases, and the blackening effect of the ridge region 5 is improved.

[0059] Further, the first ridge 52 preferably includes one or more, more preferably two or more annular recesses 522a to 522c. Further, the recess amount D22 of the annular recesses 522a to 522c is in the range of 0.05 ≦ D22 / Rm ≦ 0.50 with respect to the outer diameter Rm of the minimum circumscribed circle M, and preferably in the range of 0.10 ≦ D22 / Rm ≦ 0.40.

[0060] The recess amount D22 of the annular recesses 522a to 522c is defined as the distance between the tangent lines in contact with the adjacent annular convex portions 521a, 321b; 321b, 321c; 521c, 321a and the maximum recess position of the annular recesses 522a to 522c.

[0061] For example, in the configuration of FIG. 6, in a plan view of the tire side surface, the first ridge 52 has an annular structure formed by alternately connecting three annular convex portions 521a to 521c and three annular recesses 522a to 522c in the circumferential direction. Each of the three annular convex portions 521a to 521c is inscribed in the minimum circumscribed circle M and is arranged at circumferential intervals θa to θc of 120 [deg]. Therefore, the three annular convex portions 521a to 521c are arranged point-symmetrically with respect to the ridge center O.

[0062] Further, as shown in FIG. 5, a plurality of ridge units U are repeatedly arranged in the plane direction of the tire side portion and are arranged in close contact with each other. At this time, the separation distance Dr between adjacent first ridges 52, 52 is in the range of 0.10 [mm] ≦ Dr ≦ 1.10 [mm], and preferably in the range of 0.20 [mm] ≦ Dr ≦ 0.80 [mm]. By the above lower limit, the light absorption effect due to the adjacent first ridges 52, 52 having a gap is ensured, and by the above upper limit, the light absorption rate between the adjacent first ridges 52, 52 is ensured, and the blackening effect of the ridge region 5 is ensured. Note that, as will be described later, the adjacent first ridges 52, 52 may be connected to each other (see FIG. 17).

[0063] The separation distance Dr between adjacent first ridges 52, 52 is measured as the distance between the center lines of the first ridges 52, 52 in a plan view. However, in a configuration where adjacent ridges have a partial connection portion, the separation distance Dr is measured excluding this connection portion.

[0064] Also, as shown in FIG. 5, the annular convex portion 521a of one of the pair of adjacent first ridges 52, 52 is inserted into the annular concave portion 522b of the other first ridge 52. Specifically, the annular convex portion 521a of one of the first ridges 52 is inserted into the annular concave portion 522b of the other first ridge 52 beyond the tangent line in contact with the adjacent annular convex portions 521b, 521c of the other first ridge 52. In such a configuration, since the adjacent first ridges 52, 52 are arranged to overlap each other, the arrangement density of the ridges 52 increases, and the blackening effect by the ridge region 5 is improved.

[0065] Further, the overlap amount Do between the annular convex portion 521a of one of the first ridges 52 and the annular concave portion 522b of the other first ridge 52 is in the range of 0.10 ≦ Do / Rm with respect to the outer diameter Rm of the minimum circumscribed circle M, preferably in the range of 0.20 ≦ Do / Rm. At the upper limit of the ratio Do / Rm, the annular convex portion 521a of one of the first ridges 52 and the annular concave portion 522b of the other first ridge 52 are in contact with each other, and the overlap amount Do is equal to the recess amount D22 of the annular concave portions 522a to 522c (see FIG. 6) (Do = D22).

[0066] Furthermore, it is preferable that two or more annular convex portions 521a to 521c of one first ridge 52 are inserted into the annular concave portions 522a to 522c of two or more adjacent other first ridges 52, 52. That is, it is preferable that one first ridge 52 inserts the first annular convex portion 521a among the two or more annular convex portions 521a to 521c into the annular concave portion 522b of one of the adjacent first ridges 52, and inserts the second annular convex portion 521c into the annular concave portion (reference numeral omitted in the figure) of the other adjacent first ridge 52.

[0067] For example, in the configuration of FIG. 5, each of the first ridges 52 of the plurality of ridge units U (UA to UD) includes three annular convex portions 521a to 521c and three annular concave portions 522a to 522c (see FIG. 6). Further, by arranging a large number of ridge units U in a predetermined arrangement pattern, one first ridge 52 is surrounded by six first ridges 52 (not shown) and adjacent to them. At this time, the three annular convex portions 521a to 521c of one first ridge 52 (see FIG. 6) are inserted into the annular concave portions 522a to 522c of the three first ridges 52, and the three annular convex portions 521a to 521c of the remaining three first ridges 52 are inserted into the three annular concave portions 522a to 522c of one first ridge 52. Thereby, one first ridge 52 and the six surrounding first ridges 52 are arranged so as to overlap each other.

[0068] In addition, in the configuration of FIG. 6, the first ridge 52 has a shape formed by curving a single line, that is, a so-called one-stroke shape. Such a configuration is preferable in terms of improving the workability of the first ridge 52. However, it is not limited to this, and the single first ridge 52 may have a branch portion that branches from the main body portion constituting the above-described annular structure or notched annular structure into a T-shape or a Y-shape (not shown). Such a configuration is preferable in that the line density of the ridge 52 increases and the blackening effect of the ridge region 5 is enhanced.

[0069] Further, in the configuration of FIG. 6, the entire first ridge 52 has a curved shape with a continuous curvature. That is, the first ridge 52 has a shape formed by smoothly connecting a plurality of arcs, and therefore does not have a straight portion or a corner portion bent in an L-shape. Such a configuration is preferable in terms of improving the viewing angle uniformity of the ridge region 5. However, it is not limited to this, and a part of the first ridge 52 may have a straight portion (not shown). In this case, the length of the straight portion is in the range of 70% or less, preferably 65% or less, with respect to the outer diameter Rm of the minimum circumscribed circle M of the first ridge 52. Also, a part of the first ridge 52 may have a corner portion (not shown).

[0070] Also, in the configuration of FIG. 6, since the first ridge 52 has a curved shape with a continuous curvature as described above, it does not have a pair of straight portions arranged in parallel. Further, as shown in FIG. 5, adjacent first ridges 52, 52 do not have a pair of straight portions arranged in parallel. In such a configuration, since there are no parallel straight portions, it is preferable in terms of improving the viewing angle uniformity of the ridge region 5. Even in a configuration where adjacent curved portions have a certain separation distance (see FIG. 5), the blackening effect of the ridge region 5 in different-direction viewing is properly ensured.

[0071] As shown in FIG. 6, the second ridge 53 extends along the inner circumference of the first ridge 52. Specifically, the second ridge 53 extends in parallel with the first ridge 52 while leaving a predetermined separation distance D23 from the inner circumferential wall surface of the first ridge 52, constituting a double structure of the ridge. Thereby, the light absorption rate and the diffuse reflection effect between the first ridge 52 and the second ridge 53 are promoted, and the blackening effect of the ridge region 5 is improved.

[0072] Also, the separation distance Dr’ (see FIG. 6) between the first ridge 52 and the second ridge 53 is in the range of 0.10 [mm] ≦ Dr’ ≦ 1.10 [mm], preferably in the range of 0.20 [mm] ≦ Dr’ ≦ 0.80 [mm]. With the above lower limit, the light absorption effect due to the first and second ridges 52, 53 having a gap is ensured, and with the above upper limit, the light absorption rate between the first and second ridges 52, 53 is ensured, and the blackening effect of the ridge region 5 is ensured. Note that, as will be described later, a part of the first and second ridges 52, 53 may be connected to each other (not shown).

[0073] The separation distance Dr’ between adjacent ridges 52, 53 is measured as the distance between the center lines in the plan view of the ridges 52, 53. However, in a configuration where adjacent ridges have a partial connection portion, the separation distance Dr’ is measured excluding this connection portion.

[0074] Further, the peripheral length L2 of the second ridge 53 (dimension symbols in the figure are omitted) is in the range of 0.60 ≦ L2 / L1 with respect to the peripheral length L1 of the first ridge 52, preferably in the range of 0.80 ≦ L2 / L1. Thereby, the length in which the first ridge 52 and the second ridge 53 extend in parallel is ensured, and the light absorption effect due to the gap between the first ridge 52 and the second ridge 53 is ensured. The upper limit of the ratio L2 / L1 is not particularly limited, but since the second ridge 53 extends along the inner circumference of the first ridge 52 while securing the above-described separation distance Dr', it is in the range of L2 / L1 < 1.00.

[0075] The peripheral lengths L1 and L2 of the ridges 52 and 53 are measured as the extension lengths of the center lines in the plan view of the ridges 52 and 53.

[0076] Further, as shown in FIG. 6, the second ridge 53 has an annular structure and includes two or more annular convex portions (reference numerals in the figure are omitted) that extend along two or more annular convex portions 521a to 521c of the first ridge 52, and at least one annular concave portion (reference numerals in the figure are omitted) that extends along at least one annular concave portion 522a to 522c of the first ridge 52. Thereby, the light absorption effect due to the gap between the first ridge 52 and the second ridge 53 is improved, and the light diffuse reflection effect between the ridges is promoted, improving the viewing angle uniformity of the ridge region 5.

[0077] For example, in the configuration of FIG. 6, as described above, the first ridge 52 has an annular structure formed by alternately connecting three annular convex portions 521a to 521c and three annular concave portions 522a to 522c. The second ridge 53 has a substantially similar shape obtained by reducing the first ridge 52 and extends over the entire area of the first ridge 52 along the inner circumference of the first ridge 52. Thereby, a gap between the first ridge 52 and the second ridge 53 is formed over the entire area of the first ridge 52, enhancing the blackening effect of the ridge region 5. Further, the annular convex portion of the second ridge 53 has a widened portion (reference numerals in the figure are omitted) that widens along the annular convex portions 521a to 521c of the first ridge 52. Thereby, the viewing angle uniformity of the ridge region 5 is enhanced.

[0078] However, not limited to this, the second ridge 53 may have a notch annular structure having a notch portion partially (not shown).

[0079] [Tire manufacturing method] This tire 1 is manufactured using a tire molding die capable of transferring the above-described ridge region 5 to the tire side surface.

[0080] Specifically, the tire 1 is manufactured, for example, by the following manufacturing process. First, tire members such as a bead wire constituting a bead core, a carcass ply constituting a carcass layer, a belt ply constituting a belt layer, tread rubber, sidewall rubber, and rim cushion rubber are applied to a molding machine to form a green tire (not shown). Next, the green tire is filled into a tire vulcanization mold (not shown) including a tire molding die. Next, the green tire is expanded radially outward by a pressurizing device and abuts against the tire molding die. Next, when the tire vulcanization mold is heated, the rubber molecules and sulfur molecules of the green tire are bonded and vulcanization proceeds. At this time, the shape of the molding surface of the tire molding die is transferred to the outer peripheral surface of the green tire, and the tire side surface is formed. Then, the vulcanized and molded tire is pulled out from the tire vulcanization mold and taken out.

[0081] In addition, the above-described ridge region 5 of the tire side surface is formed by irregularities formed on the molding surface of the tire molding die. The irregularities on the molding surface of the tire molding die are formed, for example, by laser processing.

[0082] [Modification example] Figs. 8 to 17 are explanatory views showing modification examples of the ridge region 5 described in Fig. 5. Fig. 18 is an explanatory view showing a modification example of the ridge region 5 described in Fig. 2. In these figures, the same components as the above-described components are denoted by the same reference numerals, and the description thereof is omitted.

[0083] In the configuration of FIG. 5, as described above, the first ridge 52 (see FIG. 6) has an annular structure formed by alternately connecting three annular convex portions 521a to 521c and three annular concave portions 522a to 522c. Further, a plurality of ridge units U (UA to UD) are arranged vertically and horizontally at a predetermined interval with the orientations of the annular convex portions 521a to 521c aligned.

[0084] In contrast, in the configuration of FIG. 8, a first row in which the orientations of the annular convex portions 521a to 521c are aligned in one direction and a second row in which the orientations are reversed in the other direction are alternately arranged. Thus, the orientations of the annular convex portions 521a to 521c do not have to be aligned.

[0085] Also, in the configuration of FIG. 5, as shown in FIG. 6, the first ridge 52 has an annular structure formed by alternately connecting three annular convex portions 521a to 521c and three annular concave portions 522a to 522c, and also has a point-symmetric structure with respect to the ridge center O which is the center of the minimum circumscribed circle M. Further, the ridge center O is within the region surrounded by the annular structure of the first ridge 52.

[0086] In contrast, in the configuration of FIG. 9, as shown in FIG. 10, one of the three annular concave portions 522a to 522c (the annular concave portion 522b) is recessed more deeply than the other two (the annular concave portions 522a and 522c), and the amount of recess D22 is set to be approximately 0.40% with respect to the outer diameter Rm of the minimum circumscribed circle M. Further, the ridge center O is outside the region surrounded by the annular structure of the first ridge 52.

[0087] Also, in the configuration of FIG. 5, as shown in FIG. 6, the first ridge 52 has an annular structure formed by alternately connecting three annular convex portions 521a to 521c and three annular concave portions 522a to 522c, and the circumferential intervals θa to θc of the three annular convex portions 521a to 521c are set to be approximately 120 [deg]. Then, as shown in FIG. 5, three adjacent first ridges 52 in a truss shape are arranged with the annular convex portions 521a to 521c inserted into the annular concave portions 522a to 522c.

[0088] In contrast, in the configuration of Fig. 11, as shown in Fig. 12, the first ridge 52 has an annular structure formed by alternately connecting four annular convex portions 521a to 521d and four annular concave portions 522a to 522d, and the circumferential intervals θa to θd of the four annular convex portions 521a to 521d are set to approximately 90 [deg]. And, as shown in Fig. 11, four first ridges 52 adjacent to each other in a lattice shape are arranged with the annular convex portions 521a to 521d inserted into the annular concave portions 522a to 522d.

[0089] Similarly, in the configuration of Fig. 13, as shown in Fig. 14, the first ridge 52 has an annular structure formed by alternately connecting six annular convex portions 521a to 521f and six annular concave portions 522a to 522f, and the circumferential intervals θa to θd of the six annular convex portions 521a to 521d are set to approximately 60 [deg]. And, as shown in Fig. 13, four first ridges 52 adjacent to each other in a lattice shape are arranged with the annular convex portions 521a to 521f inserted into the annular concave portions 522a to 522f.

[0090] On the other hand, in the configuration of Fig. 15, as shown in Fig. 16, the first ridge 52 has an annular structure formed by alternately connecting two annular convex portions 521a, 521b and two annular concave portions 522a, 522b, and the circumferential interval θa of the two annular convex portions 521a, 521b is set to approximately 180 [deg]. And, as shown in Fig. 15, in a pair of adjacent ridge units UA, UB, the annular convex portion 521a of one first ridge 52 is inserted into the annular concave portion 522a of the other first ridge 52.

[0091] Also, in the configuration of Fig. 5, the first ridge 52 has a continuous annular structure (see Fig. 6), and a plurality of ridge units UA to UD are arranged spaced apart from each other in a predetermined arrangement pattern.

[0092] In contrast, in the configuration of Fig. 17, a plurality of ridge units UA to UD arranged are interconnected and partially divided so that the ridge region 5 can be formed in a so-called one-stroke manner. Specifically, the molding surface of the tire molding die has irregularities for forming the ridge region 5, and the arrangement structure of the plurality of ridge units UA to UD in the ridge region 5 is designed so that the irregularities of this tire molding die can be formed in a one-stroke manner by laser processing. For example, in the configuration of Fig. 17, adjacent ridge units UA, UB; UC, UD are interconnected so that the ridge portion shown by the solid line becomes the forward path and the ridge portion shown by the broken line becomes the return path, and each of the ridge units UA to UD is divided into two. At this time, if the dividing width of the ridge is less than 0.50 [mm], it can be said that each ridge unit UA to UD is substantially continuous. Further, not limited to the above, each ridge unit UA to UD may have an annular structure that is not divided into two by the forward path and the return path of the ridge portion being in contact with or overlapping each other (not shown).

[0093] Also, in the configuration of Fig. 2, as described above, the emblem portion 2 is composed of the ridge region 5, and the peripheral region 3 surrounding the emblem portion 2 is composed of a smooth surface. In such a configuration, it is preferable in that the emblem portion 2 is blackened and the visibility of the emblem portion 2 is improved.

[0094] In contrast, in the configuration of Fig. 18, the emblem portion 2 is composed of a smooth surface, and the peripheral region 3 surrounding the emblem portion 2 is composed of the ridge region 5. Specifically, the ridge region 5 is composed of a housing 51 (not shown. Refer to Fig. 7) surrounding the contour line of the emblem portion 2 and a plurality of ridge units UA to UD arranged in this housing 51 within the region partitioned by a pair of thin ribs 41, 42. In such a configuration, the peripheral region 3 is blackened, and the emblem portion 2 is presented with an appearance in which the contrast is reversed.

[0095] [Effect] As described above, [1] this tire 1 has a ridge region 5 formed by arranging a plurality of ridge units U (UA to UD: see FIG. 5) on the tire side surface (see FIG. 2). Further, each of the plurality of ridge units U includes a first ridge 52 having an annular structure (see FIG. 6) or a notched annular structure (not shown) having a notch in part, in a plan view of the tire side surface, and a second ridge 53 extending along the inner circumference of the first ridge 52 (see FIG. 6). Further, the first ridge 52 is formed by connecting two or more annular convex portions 521a to 521c protruding radially from the ridge center and at least one annular concave portion 522a to 522c recessed toward the ridge center O.

[0096] In such a configuration, (1) since the tire side surface has a ridge region 5 formed by arranging a plurality of ridge units U, the light absorption rate in the ridge region 5 (emblem portion 2 in FIG. 3) is relatively larger than the light absorption rate in other regions (peripheral region 3 in FIG. 3) in a plan view of the tire side portion. As a result, the ridge region 5 is relatively blackened, and the contrast of the tire side surface becomes clear. Further, (2) since the first ridge 52 has two or more annular convex portions 521a to 521c, the diffuse reflection action of light between the ridges is promoted, and the viewing angle uniformity of the ridge region 5, that is, the uniformity of the blackening action of the ridge region 5 when the tire side surface is viewed from different directions is improved. Further, (3) since the first ridge 52 has at least one annular concave portion 522a to 522c, the peripheral length of the first ridge 52 increases, and the blackening action of the ridge region 5 is improved. Furthermore, (4) since the second ridge 53 extends along the inner circumference of the first ridge 52 that is curved, the light absorption rate and the diffuse reflection action between the first ridge 52 and the second ridge 53 are promoted. Thereby, there is an advantage that the visibility of the tire side surface is improved.

[0097] Further, [2] this tire 1 is the tire 1 described in [1] above, in which two or more annular convex portions 521a to 521c have a smoothly curved arch shape (see FIG. 6). In such a configuration, there is an advantage that the diffuse reflection action of light between the ridges is promoted, and the viewing angle uniformity of the ridge region 5 is improved.

[0098] Further, in the tire 1 described in [1] or [2] above, the tire 1 has widened portions where two or more annular convex portions 521a to 521c widen toward the maximum protruding position from the ridge center O (see FIG. 6). In such a configuration, compared with a configuration in which a pair of ridge portions constituting each of the annular convex portions 521a to 521c extend with a certain separation distance (not shown), the peripheral length of the curved portion in the annular convex portions 521a to 521c increases, the blackening effect of the ridge region 5 is improved, and there is an advantage that the viewing angle uniformity of the ridge region 5 is improved.

[0099] Further, in the tire 1 described in any one of [1] to [3] above, the tire 1 has at least one annular concave portion 522a to 522c having a smoothly curved arch shape (see FIG. 6). In such a configuration, there is an advantage that the diffuse reflection effect of light between the ridges is promoted and the viewing angle uniformity of the ridge region 5 is improved.

[0100] Further, in the tire 1 described in any one of [1] to [4] above, the first ridge 52 of the tire 1 has two or more annular concave portions 522a to 522c. Thereby, there is an advantage that the blackening effect of the ridge region 5 is improved and the viewing angle uniformity of the ridge region 5 is improved.

[0101] Further, in the tire 1 described in any one of [1] to [5] above, the separation distance Dr between adjacent first ridges 52, 52 is in the range of 0.10 [mm] ≦ Dr ≦ 1.10 [mm] (see FIG. 5). Thereby, the arrangement density of the ridges is ensured, and there is an advantage that the blackening effect of the ridge region 5 is improved.

[0102] Further, [7] in the tire 1 described in any one of [1] to [6] above, one of the annular convex portions 521a to 521c of three or more of one of the adjacent first ridges 52, 52 (in FIG. 5, the annular convex portion 521a) is inserted into at least one annular concave portion 522b of the other first ridge 52. In such a configuration, since the adjacent first ridges 52, 52 are arranged so as to overlap each other, there is an advantage that the arrangement density of the ridges is increased and the blackening effect by the ridge region 5 is improved.

[0103] Further, [8] in the tire 1 described in any one of [1] to [7] above, a plurality of ridge units UA to UD are connected to each other (see FIG. 17). Thereby, there is an advantage that the processing of the vulcanization mold for forming the ridge region 5 becomes easy.

[0104] Further, [9] in the tire 1 described in any one of [1] to [8] above, the recess amounts D22 of the annular concave portions 522a to 522c are in the range of 0.05 ≦ D22 / Rm ≦ 0.50 with respect to the outer diameter Rm of the minimum circumscribing circle M of the first ridge 52. By the above lower limit, the peripheral length of the first ridge 52 is ensured and the blackening effect by the ridge region 5 is ensured. By the above upper limit, there is an advantage that the imbalance in the shape of the first ridge 52 due to the annular concave portions 522a to 522c becoming excessive is avoided.

[0105] Further,

[10] in the tire 1 described in any one of [1] to [9] above, the outer diameter Rm of the minimum circumscribing circle M of the first ridge 52 is in the range of 0.80 [mm] ≦ Rm ≦ 20.00 [mm]. By the above lower limit, the workability of the first ridge 52 is ensured. By the above upper limit, there is an advantage that the arrangement density of the first ridge 52 in the ridge region 5 can be ensured.

[0106] Further,

[11] in the tire 1 described in any one of [1] to

[10] above, the separation distance Dr' (see FIG. 6) between the first ridge 52 and the second ridge 53 is in the range of 0.10 [mm] ≦ Dr' ≦ 1.10 [mm]. Due to the above lower limit, the light absorption effect due to the first and second ridges 52 and 53 having a gap is ensured, and due to the above upper limit, the light absorption rate between the first and second ridges 52 and 53 is ensured, and there is an advantage that the blackening effect of the ridge region 5 is ensured.

[0107] Further,

[12] in the tire 1 described in any one of [1] to

[11] above, the peripheral length L2 of the second ridge 53 (dimension symbols in the figure are omitted) is in the range of 0.60 ≦ L2 / L1 with respect to the peripheral length L1 of the first ridge 52. Thereby, the length in which the first ridge 52 and the second ridge 53 extend in parallel is ensured, and the light absorption effect due to the gap between the first ridge 52 and the second ridge 53 is ensured.

[0108] Further,

[13] in the tire 1 described in any one of [1] to

[12] above, the second ridge 53 has an annular structure in a plan view of the tire side surface, and two or more annular convex portions (symbols in the figure are omitted) extending along two or more annular convex portions 521a to 521c of the first ridge 52, and at least one annular concave portion (symbols in the figure are omitted) extending along at least one annular concave portion 522a to 522c of the first ridge 52. Thereby, the light absorption effect due to the gap between the first ridge 52 and the second ridge 53 is improved, and the irregular reflection effect of light between the ridges is promoted, and there is an advantage that the viewing angle uniformity of the ridge region 5 is improved.

[0109] [Applicable object] In this embodiment, as described above, a pneumatic tire has been described as an example of the tire. However, it is not limited to this, and the configuration described in this embodiment can be arbitrarily applied to other tires within the scope obvious to those skilled in the art. Examples of other tires include, for example, airless tires and solid tires.

Example

[0110] Figure 19 is a chart showing the results of the performance test of the tire according to the embodiment of the present invention.

[0111] In this performance test, for a plurality of types of test tires, evaluations were made on (1) the blackening performance of the ridge region and (2) the viewing angle uniformity performance of the ridge region. Also, a test tire of tire size 255 / 35R19 (96Y) was assembled to a rim of rim size 19×9J, and the test tire was applied with the internal pressure specified by JATMA.

[0112] (1) In the evaluation of the visibility performance of the emblem part, an inspector visually observes the tire side part of the test tire from a distance of 5 [m], and performs a sensory evaluation on the visibility of the ridge region, particularly the degree of blackening (contrast with the surroundings) of the ridge region. This evaluation is performed by index evaluation based on the comparative example as the reference (100), and the larger the numerical value, the more preferable.

[0113] (2) In the evaluation of the viewing angle uniformity performance of the ridge region, an inspector visually observes the tire side part of the test tire while rotating it by 120 [deg] each time from a distance of 5 [m], and performs a sensory evaluation on whether the visibility of the ridge region, particularly the degree of blackening of the ridge region, is uniform. This evaluation is performed by index evaluation based on the comparative example as the reference (100), and the larger the numerical value, the more preferable.

[0114] The test tire of the example has the configuration described in FIGS. 1 to 7, and the emblem part 2 is composed of a ridge region 5 in which a plurality of ridge units UA to UD are arranged. Also, the first ridge 52 has an annular structure formed by alternately connecting three annular convex portions 521a to 521c and three annular concave portions 522a to 522c, and the second ridge 53 has a substantially similar shape obtained by reducing the first ridge 52. Also, the outer diameter Rm of the minimum circumscribing circle M is 10.00 [mm].

[0115] The test tire of the comparative example includes six branch portions having a linear shape branched in an asterisk shape from the ridge center.

[0116] As shown by the test results, it can be seen that in the test tire of the example, the blackening performance and the viewing angle uniformity performance of the ridge region are improved.

Explanation of Signs

[0117] 1 Tire; 11 Bead core; 12 Bead filler; 13 Carcass layer; 14 Belt layer; 141, 142 Cross belt; 143 Belt cover; 15 Tread rubber; 16 Sidewall rubber; 17 Rim cushion rubber; 20 Rim; 2 Emblem part; 21A to 21E Elements; 3 Peripheral region; 41, 42 Thin ribs; 5 Ridge region; 51 Housing; 52 First ridge; 521a to 521f Annular convex portions; 522a to 522f Annular concave portions; 523 Second ridge; U, UA to UD Ridge units

Claims

1. A tire having a ridge region formed by arranging a plurality of ridge units on a tire side surface, wherein each of the plurality of ridge units includes a first ridge having an annular structure or a notched annular structure having a notch in part, in a plan view of the tire side surface, and a second ridge extending along an inner circumference of the first ridge, and the first ridge is formed by connecting two or more annular convex portions protruding radially from a ridge center and at least one annular concave portion recessed toward the ridge center.

2. The tire according to claim 1, wherein the two or more annular convex portions have a smoothly curved arch shape.

3. The tire according to claim 1, wherein the two or more annular convex portions have a widened portion that widens toward a maximum protruding position from the ridge center.

4. The tire according to claim 1, wherein the at least one annular concave portion has a smoothly curved arch shape.

5. The tire according to claim 1, wherein the first ridge has two or more of the annular concave portions.

6. The tire according to claim 1, wherein a separation distance Dr between adjacent first ridges is in a range of 0.10 [mm] ≤ Dr ≤ 1.10 [mm].

7. The tire according to claim 1, wherein one of the three or more annular convex portions of one of the adjacent first ridges is inserted into the at least one annular concave portion of the other first ridge.

8. The tire according to claim 1, wherein the plurality of ridge units are connected to each other.

9. The tire according to claim 1, wherein a recess amount D22 of the annular concave portion is in a range of 0.05 ≤ D22 / Rm ≤ 0.50 with respect to an outer diameter Rm of a minimum inclusion circle M of the first ridge.

10. The tire according to claim 1, wherein the outer diameter Rm of the minimum inclusion circle M of the first ridge is in a range of 0.80 [mm] ≤ Rm ≤ 20.00 [mm].

11. The tire according to claim 1, wherein a separation distance Dr' between the first ridge and the second ridge is in a range of 0.10 [mm] ≤ Dr' ≤ 1.10 [mm].

12. The tire according to claim 1, wherein a peripheral length L2 of the second ridge is in a range of 0.60 ≤ L2 / L1 with respect to a peripheral length L1 of the first ridge.

13. The tire according to claim 1, wherein the second ridge has an annular structure in a plan view of the tire side surface, and includes two or more annular convex portions extending along the two or more annular convex portions of the first ridge and at least one annular concave portion extending along the at least one annular concave portion of the first ridge.

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