tire

Abstract

To provide a tire that can improve the blackening performance and visual angle uniformity performance of the ridge area. [Solution] This tire 1 is provided with a ridge region 5 on the tire side surface. The ridge region 5 consists of a mesh-like ridge 52 that divides a plurality of cells C in a plan view of the tire side surface. The plurality of cells C have a concave polygon shape, and are arranged adjacent to each other with the recesses 521 (521A~521D) and protrusions of the concave polygon interlocking. The outer diameter Rm of the smallest inclusion circle of a cell C is in the range of 0.05 [mm] ≤ Rm ≤ 5.00 [mm].

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] Recent tires employ a configuration in which marks such as side brands are blackened using a ridge region composed of ridges to improve the visibility of the marks. 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 needs to be made uniform when the tire side surface is viewed from different directions. As a conventional tire related to 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] To achieve the above objective, the tire according to this invention is a tire having a ridge region on the tire side surface, wherein the ridge region consists of a mesh-like ridge that divides a plurality of cells in a plan view of the tire side surface, the plurality of cells having concave polygons and being arranged adjacent to each other with the concave and convex portions of the concave polygons interlocking, and the outer diameter Rm of the smallest inclusion circle of the cells is in the range of 0.05 [mm] ≤ Rm ≤ 5.00 [mm]. [Effects of the Invention]

[0006] In the tire according to this invention, (1) since the tire has a ridge region on the tire side surface, the light absorption rate in the ridge region is relatively higher than the light absorption rate in other regions. This has the advantage that the ridge region is relatively blackened, and the contrast of the tire side surface is made clearer. Also, (2) since the multiple cells partitioned by the ridge are arranged with the recesses and protrusions of the concave polygon interlocking with each other, compared to a configuration in which the cells have a convex polygon, ridge wall surfaces facing each other at various angles are formed within the cell. This has the advantage that diffuse reflection of light is promoted, improving the performance of uniformity of the viewing angle in the ridge region. Also, (3) by setting the outer diameter Rm of the minimum inclusion circle of the cell to be small, the blackening effect by the ridge is ensured. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a cross-sectional view of a tire in the meridian direction, showing a tire according to an embodiment of this invention. [Figure 2] Figure 2 is a plan view showing the tire sidewall of the tire described in Figure 1. [Figure 3] Figure 3 is an enlarged view showing the markings on the tire sidewall as described in Figure 2. [Figure 4] Figure 4 is an explanatory diagram showing the ridge region of the tire sidewall as described in Figure 2. [Figure 5] Figure 5 is an enlarged plan view showing a portion of the ridge region described in Figure 4. [Figure 6]Figure 6 is a magnified view showing a single cell partitioned by a ridge. [Figure 7] Figure 7 is an explanatory diagram showing the method for drawing the cells described in Figure 6. [Figure 8] Figure 8 is a cross-sectional view showing the ridge region described in Figure 5. [Figure 9] Figure 9 is an explanatory diagram showing a modified example of the ridge region described in Figure 5. [Figure 10] Figure 10 is an explanatory diagram showing a modified example of the ridge region described in Figure 5. [Figure 11] Figure 11 is an explanatory diagram showing a modified example of the ridge region described in Figure 2. [Figure 12] Figure 12 is a diagram showing the results of a performance test of a tire according to an embodiment of this invention. [Modes for carrying out the invention]

[0008] The present invention will be described in detail below with reference to the drawings. However, this embodiment does not limit the present invention. Furthermore, the components of this embodiment include those that are substituted and obvious for substitution while maintaining the identity of the invention. In addition, the various modifications described in this embodiment can be arbitrarily combined within the scope of what is obvious to those skilled in the art.

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

[0010] In the same figure, the cross section in the tire meridian direction is defined as a cross section when the tire is cut by a plane including the tire rotation axis (not shown). The tire equatorial plane CL is defined as a plane that passes through the midpoint of the tire cross-sectional width specified in JATMA and is perpendicular to the tire rotation axis. The tire width direction is defined as a direction parallel to the tire rotation axis, and the tire radial direction is defined as a direction perpendicular to the tire rotation axis. Point T is the tire ground contact 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, 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 annularly and multiply winding one or a plurality of bead wires made of steel, and are embedded in the bead portions to constitute the cores of the left and right bead portions. The pair of bead fillers 12, 12 are respectively arranged on the outer peripheries in the tire radial direction of the pair of bead cores 11, 11 to reinforce the bead portions.

[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 toroidally bridged between the left and right bead cores 11, 11 to constitute the framework of the tire. Both end portions of the carcass layer 13 are folded back outward in the tire width direction so as to wrap around the bead cores 11 and the bead fillers 12, and are locked. The carcass ply of the carcass layer 13 is configured by coating a plurality of carcass cords made of steel or organic fiber materials (for example, aramid, nylon, polyester, rayon, etc.) with coating rubber and rolling the same, and has a cord angle of 80[deg] or more and 100[deg] or less (defined as the inclination angle in 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 wrapped around the outer periphery 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 configured by coating a plurality of belt cords made of steel or an organic fiber material with coating rubber and rolling the coated cords, and have a cord angle (defined as the inclination angle of the longitudinal direction of the belt cords relative to the tire circumferential direction) of 15[deg] or more and 55[deg] or less in absolute value. 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 (a so-called cross-ply structure). The pair of intersecting belts 141, 142 are disposed so as to be laminated on the outer side of the carcass layer 13 in the tire radial direction.

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

[0017] The tread rubber 15 is disposed on the outer peripheries of the carcass layer 13 and the belt layer 14 in the tire radial direction to constitute the tread portion of the tire 1. The tread rubber 15 is made of a rubber material having excellent ground contact characteristics and weather resistance, and is exposed over the entire area of the tire outer peripheral surface to constitute the tread surface. The pair of sidewall rubbers 16, 16 are respectively disposed on the outer side of the carcass layer 13 in the tire width direction 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 of the turned-up portions of the left and right bead cores 11, 11 and the carcass layer 13 to the outer side in the tire width direction, to constitute the rim fitting surfaces of the bead portions.

[0018] [Tire sidewall] Figure 2 is a plan view showing the tire sidewall of the tire described in Figure 1. Figure 3 is an enlarged view showing the marking portion 2 of the tire sidewall described in Figure 2. In these figures, Figure 2 shows a plan view of the tire 1 as seen from the axial direction, and Figure 3 shows a part of the marking portion 2.

[0019] As shown in Figure 2, the tire 1 has a marking section 2 and a surrounding area 3 on the tire sidewall.

[0020] The mark section 2 includes a mark consisting of letters, figures, or symbols, or a combination thereof, and in particular includes a trademark that functions as an identifying mark indicating a tire manufacturer, tire brand, etc. Multiple mark sections 2, 2 are arranged spaced apart in the circumferential direction of the tire. For example, in the configuration shown in Figure 2, a mark consisting of the string "YOKOHAMA" indicating the tire manufacturer and a logo featuring its initial "Y" is stamped on the surface of the tire sidewall. Furthermore, a pair of mark sections 2, 2 are arranged at opposing positions in the circumferential direction of the tire.

[0021] Furthermore, in Figure 3, the radial height H2 of elements 2A to 2E constituting the emblem 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. This improves the visibility of the emblem 2.

[0022] The radial height H2 of elements 2A to 2E is measured as the maximum extent of the extended length of elements 2A to 2E in the radial direction of the tire.

[0023] The tire section height SH is half the difference between the tire's outer diameter and its rim diameter, and is measured under no-load conditions with the tire mounted on a specified rim and under specified internal pressure.

[0024] The specified rim refers to the "applicable rim" specified by JATMA, the "Design Rim" specified by TRA, or the "Measuring Rim" specified by ETRTO. The specified internal pressure refers to the "maximum air pressure" specified by JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified by TRA, or the "INFLATION PRESSURES" specified by ETRTO. The specified load refers to the "maximum load capacity" specified by JATMA, the maximum value of "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES" specified by TRA, or the "LOAD CAPACITY" specified by ETRTO. However, in JATMA, for passenger car tires, the specified internal pressure is 180 [kPa] air pressure, and the specified load is 88 [%] of the maximum load capacity.

[0025] The peripheral region 3 is the area surrounding the emblem portion 2 and is formed on the surface of the tire side portion. This peripheral region 3 may be a smooth surface with a smooth surface, or it may be an uneven surface that has been surface-treated.

[0026] For example, in the configuration shown in Figure 2, the peripheral region 3 is a smooth surface, having a continuous, smooth surface without grooves or unevenness. Furthermore, the peripheral region 3 is positioned to surround the entire emblem 2, thereby enhancing the visibility of the emblem 2. Additionally, the peripheral region 3 is formed between a pair of thin ribs 41 and 42 extending in the circumferential direction of the tire, thereby enhancing the design of the tire sidewall. Moreover, a single peripheral region 3 has an annular structure that extends around the entire circumference of the tire sidewall, surrounding the pair of emblem sections 2, 2.

[0027] Furthermore, in the configuration shown in Figure 2, the emblem portion 2 and the surrounding area 3 are positioned radially outward from the tire's maximum width position Ac. More specifically, a pair of thin ribs 41 and 42 extending in the circumferential direction of the tire are arranged in the area from the tire's contact edge T to the tire's maximum width position Ac (see Figure 1), and the emblem portion 2 and the surrounding area 3 are positioned between these thin ribs 41 and 42. This enhances the visibility of the emblem portion 2. However, the configuration is not limited to this; the emblem portion 2 and the surrounding area 3 may also be positioned intersecting the tire's maximum width position Ac, or positioned radially inward from the tire's maximum width position Ac (not shown).

[0028] The tire's maximum width position Ac is defined as the position where the tire's cross-sectional width is at its widest point.

[0029] The tire section width is measured as the straight-line distance between the sidewalls, excluding patterns, lettering, etc., when the tire is mounted on a specified rim, subjected to specified internal pressure, and under no-load conditions.

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

[0031] The pair of thin ribs 41 and 42 described above have a width of 0.4 mm to 0.8 mm and a height of 0.1 mm to 1.0 mm, and function as a discharge path for residual air during tire vulcanization molding. This suppresses the occurrence of vulcanization failures in the marking area 2 and the surrounding area 3. In addition, in the configuration shown in Figure 2, the thin rib 41 on the outer diameter side is located at the split position of the mold of the tire molding die.

[0032] Furthermore, in Figure 3, the radial height H2 [mm] of the elements 2A to 2E constituting the emblem 2 is in the range of 0.30 ≤ H2 / H4 ≤ 0.80 with respect to the spacing H4 [mm] between the thin ribs 41 and 42 in the radial direction of the tire, preferably in the range of 0.40 ≤ H2 / H4 ≤ 0.70. Also, as shown in Figure 3, it is preferable that the emblem 2 is spaced apart from the pair of thin ribs 41 and 42. This improves the visibility of the emblem 2.

[0033] [Ridge region] Figures 4 to 8 are explanatory diagrams showing the ridge region 5 of the tire sidewall as described in Figure 2. In these figures, Figure 4 shows one element 2A that constitutes the mark portion 2 as described in Figure 3, Figure 5 is an enlarged plan view showing a part of the ridge region 5 as described in Figure 4, Figure 6 is an enlarged view showing a single cell C partitioned by the ridge 52, Figure 7 is an explanatory diagram showing the method of drawing the cell as described in Figure 6, and Figure 8 is a cross-sectional view showing the ridge region 5 as described in Figure 5. Here, as an example, a configuration in which the mark portion 2 consists of the ridge region 5 will be described.

[0034] As shown in Figure 8, the ridge region 5 consists of a housing 51 and a ridge 52.

[0035] The housing 51 is a frame-shaped recess formed on the tire side surface, and forms the outline of the mark portion 2 in a plan view of the tire side portion. The depth H51 of the housing 51 (see Figure 8) is in the range of 0.10 [mm] ≤ H51 ≤ 3.00 [mm], and 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 of the housing 51 (the surface of peripheral region 3 in Figure 8) to the bottom surface of the housing 51.

[0037] As shown in Figure 8, the ridge 52 is a rib-shaped protrusion that extends from the bottom surface of the housing 51 and has a cross-sectional shape that narrows in width towards the top. Also, as shown in Figure 5, the ridge 52 is formed throughout the entire interior of the housing 51. The planar shape of the ridge 52 will be described in detail later.

[0038] For example, in the configuration shown in Figure 3, the trademark portion 2 is formed by a ridge region 5, as shown in Figure 4. Specifically, the logo 2A constituting the trademark portion 2 consists of a combination of multiple parallel-arranged thin lines. The outlines of these thin lines are formed by the edges of the housing 51 (see Figure 8), which will be described later. Similarly, other components constituting the trademark portion 2 (for example, elements 2B to 2E in Figure 3) consist of thick lines representing letters, and the outlines of these thick lines are formed by the edges of the housing 51 (not shown). Also, as shown in Figure 8, the ridge 52 has a uniform trapezoidal or triangular cross-section. The ridge 52 extends across the entire area of ​​the housing 51, filling the inside of the housing 51. Thus, the trademark of the trademark portion 2 is represented by the housing 51 and the ridge 52.

[0039] In the above configuration, the tire side surface is provided with a ridge region 5 consisting of a ridge 52. Therefore, in a plan view of the tire side surface, the light absorption rate in the ridge region 5 (marked area 2 in Figure 3) is relatively higher than the light absorption rate in other areas (peripheral area 3 in Figure 3). As a result, the ridge region 5 is relatively blackened, the contrast of the tire side surface becomes clearer, and the visibility of the tire side surface is improved.

[0040] Furthermore, in the configuration shown in Figure 8, the height H52 of the ridge 52 is in the range of 0.30 ≤ H52 / H51 < 1.00 relative to the depth H51 of the housing 51, and preferably in the range of 0.50 ≤ H52 / H51 ≤ 0.95. Therefore, the top of the ridge 52 is embedded within the housing 51. This configuration is preferable because it suppresses the deterioration of air resistance on the tire side surface caused by the ridge 52 protruding from the tire side surface. However, it is not limited to this configuration, and the ridge 52 may protrude from the tire side surface if the height H52 of the ridge 52 is in the range of 1.00 ≤ H52 / H51 relative to the depth H51 of the housing 51 (not shown). In this configuration, when wax is applied to the tire side surface, the wax is more easily applied to the top of the ridge 52, improving the wax retention on the tire side surface.

[0041] The height H52 of the ridge 52 is defined as the distance from the top of the ridge 52 to the bottom of the housing 51, as shown in Figure 8, and is specifically measured as the height distance from the top of the ridge 52 to the bottom of the valley between adjacent ridge side walls.

[0042] Furthermore, in Figure 8, the width W52A of the top of the ridge 52 is in the range of 0 ≤ W52A / W52B ≤ 0.90 relative to the width W52B of the base of the ridge 52, preferably in the range of 0.10 ≤ W52A / W52B ≤ 0.70. The lower limit suppresses deterioration of the processability of the ridge 52 caused by the top of the ridge 52 being too thin, and the upper limit improves the blackening effect of the ridge 52 on the tire side surface.

[0043] The widths W52A and W52B of the ridge 52 are measured as the width in a cross-section perpendicular to the longitudinal direction of the ridge 52. The width W52B of the base of the ridge 52 is defined as the width of the bottom surface of the ridge 52 (in Figure 8, the contact surface between the base of the ridge 52 and the bottom surface of the housing 51).

[0044] Furthermore, the width W52B of the base of the ridge 52 is in the range of 0.05 [mm] ≤ W52B ≤ 0.50 [mm], preferably in the range of 0.10 [mm] ≤ W52B ≤ 0.30 [mm]. The lower limit ensures the strength and processability of the ridge 52, and the upper limit improves the blackening effect of the ridge 52 on the tire side surface.

[0045] Furthermore, the height H52 of the ridge 52 is within the range of 2.00 ≤ H52 / W52B relative to the width W52B of the base of the ridge 52. This ensures that the height H52 of the ridge 52 is maintained, and that the blackening effect of the ridge 52 on the tire side surface is ensured. There is no particular upper limit to the ratio H52 / W52B, but it is constrained by other requirements.

[0046] In the configuration shown in Figure 2, the ridge region 5 consists of a housing 51 and a ridge 52 formed within the housing 51 (see Figures 5 and 8). However, the configuration is not limited to this; the housing 51 may be omitted, and the ridge region 5 may consist only of the ridge 52 (not shown). For example, the ridge 52 may protrude from the same plane as the surrounding region 3. Even with such a configuration, the visibility of the emblem 2 can be improved.

[0047] Furthermore, in the configuration shown in Figure 2, the peripheral region 3 is a smooth surface. This configuration is preferable because it improves the visibility of the mark portion 2, which consists of the housing 51 and the ridge 52. However, it is not limited to this, and the peripheral region 3 may also be an uneven surface with a surface treatment (not shown). The uneven surface with a surface treatment may be composed of a plurality of arranged uneven portions, for example, a plurality of longitudinally shaped ridges or a plurality of grooves, or a plurality of hemispherical or conical protrusions or a plurality of depressions.

[0048] [Planar shape of the ridge] As shown in Figure 5, the ridge 52 extends in a mesh-like pattern in a plan view of the tire side surface, dividing multiple cells C. Furthermore, because the mesh-like structure of the ridge 52 is made up of multiple concave polygons, each of the multiple cells C has a concave polygon. In addition, the multiple cells C are arranged in a close-packed structure, that is, adjacent to each other without gaps. As a result, adjacent cells C share some sides of their concave polygons, and there are no other cells interposed between adjacent cells C.

[0049] Cell C is a space surrounded by the side walls of the mesh-like ridge 52 described above, and by setting the distance Dc between opposing wall surfaces to be very narrow, it has the effect of absorbing light from the outside. Specifically, in Figure 6, the distance Dc between opposing wall surfaces of cell C is in the range of 0.05 [mm] ≤ Dc ≤ 1.50 [mm], preferably in the range of 0.05 [mm] ≤ Dc ≤ 1.00 [mm], and more preferably in the range of 0.10 [mm] ≤ Dc ≤ 0.50 [mm]. The lower limit ensures the processability of the ridge 52, and the upper limit ensures the light absorption effect of the ridge 52.

[0050] The distance Dc between opposing walls of cell C is measured as the distance between the centerlines of the ridges 52 that demarcate cell C in a plan view of the ridge region 5. Furthermore, opposing walls in a concave polygon are defined as a combination of two sides excluding the opposite sides of the concave polygon, i.e., adjacent sides that share a vertex.

[0051] Furthermore, in Figure 6, the smallest inclusion circle of cell C (not shown), i.e., the outer diameter Rm of the smallest circle encompassing cell C, is in the range of 0.05 [mm] ≤ Rm ≤ 5.00 [mm], and preferably in the range of 0.10 [mm] ≤ Rm ≤ 1.00 [mm]. Also, the ratio of the maximum value Rm_max to the minimum value Rm_min of the outer diameter Rm of the smallest inclusion circle of multiple cells C is in the range of 1.00 ≤ Rm_max / Rm_min ≤ 1.20, and preferably in the range of 1.00 ≤ Rm_max / Rm_min ≤ 1.05. Therefore, the multiple cells C have substantially uniform sizes.

[0052] Furthermore, as shown in Figure 5, adjacent cells C, C are arranged so that the concave and convex parts of the concave polygon interlock with each other. Specifically, each of the multiple cells C has a concave part 521 (521A to 521D; see Figure 6) and a convex part (notation omitted in the figure), and the concave part 521 of one adjacent cell C, C and the convex part of the other interlock with each other, sharing an edge.

[0053] The concave portion of a concave polygon is defined as two sides forming a vertex with an interior angle of 180 degrees or more, and the convex portion of a concave polygon is defined as two sides forming a vertex with an interior angle of less than 180 degrees. Furthermore, the sides and vertices of a concave polygon are defined by the centerlines of the ridges 52 that demarcate cell C in a plan view of the ridge region 5.

[0054] In the above configuration, multiple cells C partitioned by the ridge 52 are arranged with their concave polygonal recesses and protrusions interlocking. Compared to a configuration where the cells have convex polygons (not shown), this results in the formation of ridge wall surfaces facing each other at various angles within the cells C. This promotes diffuse reflection of light, improving the performance of uniformizing the viewing angle in the ridge region 5.

[0055] Furthermore, it is preferable that each of the multiple cells C is a concave polygon having three or more recesses, that one cell C is arranged adjacent to at least three other cells, and that each of the three or more recesses of one cell fits into the protrusions of the three adjacent cells. This ensures uniformity of the viewing angle in three or more directions.

[0056] Furthermore, in Figure 6, the ratio of the maximum to minimum side lengths (dimension symbols omitted in the figure) of the concave polygon of cell C is in the range of 1.00 to 2.00, preferably in the range of 1.00 to 1.60. This ensures that the side length ratio is uniform and that the visual angle uniformity of the ridge region 5 is maintained.

[0057] The side lengths of the concave polygon of cell C are measured as the lengths of the centerlines of the ridges 52 that demarcate cell C in a plan view of the ridge region 5.

[0058] Furthermore, in Figure 6, the interior angles of the concave polygon (dimension symbols omitted in the figure) are in the range of 50 degrees to 310 degrees, preferably in the range of 55 degrees to 305 degrees. This reduces sharp vertices and ensures uniformity of the viewing angle in the ridge region 5.

[0059] The interior angle of the concave polygon of cell C is measured as the angle of the centerline of the ridge 52 that demarcates cell C in a plan view of the ridge region 5.

[0060] Furthermore, the ratio of the maximum value Sc_max to the minimum value Sc_min of the area Sc of cell C is in the range of 1.00 ≤ Sc_max / Sc_min ≤ 1.60, preferably in the range of 1.00 ≤ Sc_max / Sc_min ≤ 1.20, and more preferably in the range of 1.00 ≤ Sc_max / Sc_min ≤ 1.05. This equalizes the area of ​​multiple cells C, resulting in the ridge region 5 being uniformly blackened.

[0061] For example, in the configuration of Figure 5, as shown in Figure 6, one cell C is a concave cross triangle having four recesses 521A to 521D and nine protrusions (notation omitted in the figure), and is designed by the following construction method. First, as shown in Figure 7, a plurality of reference regular hexagons are arranged adjacent to each other in a honeycomb-like, i.e., close-packed structure. Next, each of the plurality of regular hexagons is divided into six divisions by three imaginary lines passing through the midpoints of three pairs of opposite sides. Next, eight adjacent divisions are connected to define one cell C. Similarly, a plurality of cells C are defined without gaps to define a mesh-like ridge 52 as shown in Figure 5.

[0062] In the above configuration, the concave polygon of cell C consists of a combination of three sides of different lengths. Specifically, if the length of one side of the standard regular hexagon described above is x (dimension symbol omitted in the figure), then all sides of one cell C are composed of three different lengths: x, (x)^(1 / 2), and 2x. Also, the interior angle of cell C (dimension symbol omitted in the figure) is in the range of 90 degrees to 270 degrees.

[0063] Furthermore, in the configuration shown in Figure 5, one cell C1 is adjacent to six cells C2 to C7, sharing all sides with these cells C2 to C7. In addition, one cell C1 has four recesses 521A to 521D (see Figure 6), and each of these recesses 521A to 521D is fitted into the protrusions of four different cells C2, C3, C4, and C6.

[0064] Furthermore, in the configuration shown in Figure 5, the concave polygon of cell C has a predetermined orientation due to its non-point symmetry and non-line symmetry. In addition, multiple cells C have congruent concave polygons. The multiple cells C are arranged in a non-periodic tiling pattern, specifically by irregularly changing the orientation of the concave polygons in three or more directions. This improves the visual angle uniformity of the ridge region 5 compared to a configuration in which multiple cells C are regularly arranged with the orientation of the concave polygons aligned (see, for example, Figures 9 and 10 described later).

[0065] Congruent concave polygons are defined as concave polygons that coincide when translated, rotated, and reflected. Furthermore, non-uniformity resulting from manufacturing tolerances, tire diameter differences, and curvature of the tire sidewall is acceptable.

[0066] In the configuration shown in Figure 7, one cell C is formed by combining multiple divisions based on a regular hexagon, as described above. However, it is not limited to this; one cell C may also be formed by combining eight divisions, each formed by dividing a flattened or distorted hexagon into six equal parts (not shown). In this case, the ratio of the minimum to maximum lengths of the six sides of the base hexagon (dimension symbols omitted in the figure) is preferably in the range of 0.80 to 1.00, and more preferably in the range of 0.90 to 1.00. Furthermore, the ratio of the minimum to maximum lengths of the six interior angles of the base hexagon is preferably in the range of 0.80 to 1.00, and more preferably in the range of 0.90 to 1.00.

[0067] Furthermore, in the configuration shown in Figure 7, as described above, one cell C is formed by combining eight divisions, which are obtained by dividing a regular hexagon into six equal parts. However, this is not limited to this configuration; a single cell may be formed by combining nine or more divisions (not shown in the diagram).

[0068] [Differentiation] Figures 9 and 10 are explanatory diagrams showing modified examples of the ridge region 5 described in Figure 5. In these figures, the same reference numerals are used for components that are the same as those described in Figure 5, and their descriptions are omitted.

[0069] In the configuration shown in Figure 5, as described above, the concave polygons of cell C are asymmetrical and non-linear, and multiple cells C having congruent concave polygons are arranged with their orientations irregularly changing in three or more directions.

[0070] In contrast, in the configuration shown in Figure 9, the concave polygon of cell C has a concave 24-sided polygon, which is based on a hexagon and has triangular recesses (not shown in the figure) on three of its six sides and triangular protrusions on the remaining three sides. Multiple cells C are then arranged in a close-packed structure, with the recesses and protrusions fitting together, to form a mesh-like ridge 52. Furthermore, the outer diameter Rm (dimension symbol not shown in the figure) of the smallest inclusion circle of cell C is set small enough to satisfy the above conditions. Even with this configuration, the blackening performance and visual angle uniformity performance of the ridge region 5 are ensured.

[0071] Furthermore, in the configuration shown in Figure 10, the concave polygon of cell C has a concave icosagon formed by using a quadrilateral as a base and providing triangular recesses and protrusions (not shown in the figure) on each of its four sides. Multiple cells C are then arranged in a close-packed structure with their recesses and protrusions interlocking to form a mesh-like ridge 52. In addition, the outer diameter Rm (dimension symbol not shown in the figure) of the smallest inclusion circle of cell C is set small enough to satisfy the above conditions. Even with this configuration, the blackening performance and visual angle uniformity performance of the ridge region 5 are ensured.

[0072] Figure 11 is an explanatory diagram showing a modified example of the ridge region 5 described in Figure 2. In this figure, components identical to those described in Figure 2 are denoted by the same reference numerals, and their descriptions are omitted.

[0073] In the configuration shown in Figure 2, as described above, the emblem portion 2 consists of a ridge region 5, and the surrounding region 3 is a smooth surface. This configuration is preferable because the emblem portion 2 is blackened, improving its visibility.

[0074] In contrast, in the configuration shown in Figure 11, the mark portion 2 consists of a smooth surface, and the surrounding area 3 is composed of a ridged area 5. Specifically, the ridged area 5 is composed of a housing 51 (not shown; see Figure 8) that surrounds the contour line of the mark portion 2 within an area demarcated by a pair of thin ribs 41 and 42, and a ridge 52 formed on this housing 51. In this configuration, the surrounding area 3 is blackened, and the mark portion 2 is presented with an appearance that inverts the contrast.

[0075] [effect] As described above, [1] this tire 1 is provided with a ridge region 5 on the tire side surface (see Figures 2 to 4). The ridge region 5 consists of a mesh-like ridge 52 that divides a plurality of cells C in a plan view of the tire side surface (see Figure 5). The plurality of cells C have a concave polygon shape and are arranged adjacent to each other with concave polygon recesses 521 (521A to 521D; see Figure 6) and protrusions (notation omitted in the figures) interlocking with each other. The outer diameter Rm of the smallest inclusion circle of a cell C (see Figure 6) is in the range of 0.05 [mm] ≤ Rm ≤ 5.00 [mm].

[0076] In this configuration, (1) since the tire 1 has a ridge region 5 on its side surface, the light absorption rate in the ridge region 5 (marked area 2 in Figure 3) is relatively higher than the light absorption rate in other areas (peripheral area 3 in Figure 3). This has the advantage that the ridge region 5 is relatively blackened, making the contrast of the tire side surface clearer. Also, (2) since the multiple cells C partitioned by the ridge 52 are arranged with the concave and convex parts of the concave polygon interlocking, compared to a configuration in which the cells have a convex polygon (not shown), ridge wall surfaces facing each other at various angles are formed within the cell C. This has the advantage that diffuse reflection of light is promoted, improving the performance of uniformity of the viewing angle of the ridge region 5. Also, (3) by setting the outer diameter Rm of the minimum inclusion circle of the cell C to be small, the blackening effect of the ridge 52 is ensured.

[0077] Furthermore, [2] in this tire 1, as described in [1] above, the interior angle of the concave polygon of cell C (dimension symbols omitted in the figure) is in the range of 50 [deg] to 310 [deg] (see Figure 6). This has the advantage of reducing sharp vertices and ensuring uniformity of the viewing angle in the ridge region 5.

[0078] Furthermore, [3] in the tire 1 described in [1] or [2] above, the ratio of the maximum value Sc_max to the minimum value Sc_min of the area Sc of multiple cells C is in the range of 1.00 ≤ Sc_max / Sc_min ≤ 1.60. This has the advantage that the area of ​​multiple cells C is made uniform, and the ridge region 5 is uniformly blackened.

[0079] Furthermore, [4] in this tire 1, in the tire 1 described in any one of [1] to [3] above, the width W52B (see Figure 8) of the base of the ridge 52 is in the range of 0.05 [mm] ≤ W52B ≤ 0.50 [mm]. The lower limit ensures the strength and workability of the ridge 52, and the upper limit has the advantage of improving the blackening effect of the ridge 52 on the tire side surface.

[0080] Furthermore, [5] in this tire 1, in the tire 1 described in any one of [1] to [4] above, multiple cells C have congruent concave polygons and are arranged with the orientation of the concave polygons irregularly changed (see Figure 5). This has the advantage of improving the uniformity of the viewing angle of the ridge region 5.

[0081] Furthermore, [6] in this tire 1, in any of the tire 1 described in [1] to [5] above, the ratio of the minimum and maximum side lengths (dimension symbols omitted in the figure) of the concave polygon of cell C is in the range of 1.00 to 2.00 (see Figure 6). This has the advantage of ensuring uniformity of the viewing angle of the ridge region 5 by making the side length ratio uniform.

[0082] Furthermore, [7] in this tire 1, in the tire 1 described in any one of [1] to [6] above, the concave polygon of multiple cells C is defined as a figure in which multiple hexagons are arranged in a dense structure, each of the multiple hexagons is divided into six divisions by three imaginary lines passing through the midpoints of three pairs of opposite sides, and eight adjacent divisions are connected (see Figure 7). This has the advantage of ensuring the uniformity of the viewing angle of the ridge region 5, as it has a concave polygon that is asymmetrical in both points and lines, and is congruent to each other, and multiple cells C can be arranged in an irregularly varied manner.

[0083] Furthermore, [8] in this tire 1, as described in any one of [1] to [7] above, each of the multiple cells C has three or more recesses 521A to 521D, and the three or more recesses are fitted into the other three cells C (see Figure 6). This has the advantage of promoting diffuse reflection of light and improving the performance of uniformizing the viewing angle in the ridge region 5.

[0084] Furthermore, [9] in this tire 1, in any one of the tire 1 described in [1] to [8] above, the distance Dc (see Figure 6) between opposing wall surfaces of cell C is in the range of 0.05 [mm] ≤ Dc ≤ 1.50 [mm]. This has the advantage of ensuring the blackening performance of the ridge region 5.

[0085] Furthermore,

[10] in the tire 1 described in any one of [1] to [9] above, the ratio of the maximum and minimum values ​​of the outer diameter Rm of the minimum inclusion circle of multiple cells C is in the range of 1.00 to 1.20. This has the advantage that the outer diameter Rm of multiple cells C is made uniform, and the ridge region 5 is uniformly blackened.

[0086] Furthermore,

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

[10] above is provided with a marking portion 2 and a surrounding area 3 surrounding the marking portion 2 on the tire side surface (see Figure 2). In addition, the marking portion 2 includes a ridge area 5, and the surrounding area 3 consists of a smooth surface. This has the advantage that the marking portion 2 is blackened, improving its visibility.

[0087] Furthermore,

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

[10] above is provided with a marking portion 2 and a peripheral region 3 surrounding the marking portion 2 on the tire side surface (see Figure 11). The marking portion 2 is made of a smooth surface, and the peripheral region 3 includes a ridge region 5. In this configuration, the peripheral region 3 is blackened, and the marking portion 2 is presented with an appearance that inverts the contrast. This has the advantage that the marking portion 2 is blackened, improving its visibility.

[0088] [Applicable to] In this embodiment, as described above, a pneumatic tire was explained as an example of a tire. However, the configuration described in this embodiment is not limited to this and can be arbitrarily applied to other tires within the scope of what is obvious to those skilled in the art. Examples of other tires include airless tires and solid tires. [Examples]

[0089] Figure 12 is a diagram showing the results of a performance test of a tire according to an embodiment of this invention.

[0090] In this performance test, several types of test tires were evaluated for (1) blackening performance of the ridge area and (2) uniformity of the ridge area at a visual angle. A test tire with tire size 255 / 35R19 (96Y) was mounted on a rim with a rim size of 19×9J, and this test tire was subjected to the internal pressure specified by JATMA.

[0091] (1) In the evaluation of the blackening performance of the ridge area, the inspector visually inspects the tire sidewall of the test tire from a distance of 5 [m] and performs a sensory evaluation of the visibility of the ridge area, in particular the degree of blackening of the ridge area (contrast with the surroundings). This evaluation is performed using an index evaluation with the comparative example as the baseline (100), and a higher value is preferable.

[0092] (2) In the evaluation of the performance of uniformity of the viewing angle in the ridge area, the inspector visually inspects the tire sidewall of the test tire from a distance of 5 m while rotating it 120 degrees at a time, and performs a sensory evaluation of the visibility of the ridge area, in particular whether the degree of blackening of the ridge area is uniform. This evaluation is performed using an index evaluation with the comparative example as the baseline (100), and a higher value is preferable.

[0093] The test tire of the embodiment has the configuration shown in Figures 1 to 4 and Figure 8, and the marking portion 2 is composed of a ridge region 5 consisting of multiple cells C partitioned by a mesh-like ridge 52. Furthermore, as shown in Figures 5, 9, or 10, the multiple cells C have congruent concave polygons, and each of the multiple cells C is arranged so that three concave parts fit into the convex parts of the other three cells. The depth H51 of the housing 51 (see Figure 8) is H51 = 0.80 [mm], and the height H52 of the ridge 52, the width W52A at the top, and the width W52B at the base are H52 = 0.50 [mm] and W52A = 0.10 [mm].

[0094] In the comparative example test tire, the ridge region is composed of multiple plate-shaped ridges arranged in parallel, with a linear shape in plan view (not shown). The ridge pitch length, i.e., the distance between adjacent ridges, is 1.50 mm.

[0095] As the test results show, the test tire in the example demonstrates improved blackening performance and visual angle uniformity performance in the ridge region. [Explanation of Symbols]

[0096] 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; 2 Emblem area; 20 Rim; 21A, 21B Elements; 3 Peripheral area; 41, 42 Thin ribs; 5 Ridge area; 51 Housing; 52 Ridge; 521, 521A~521D Recess; C, C1~C7 Cell

Claims

1. A tire having a ridge region on the tire side surface, The ridge region consists of a mesh-like ridge that divides multiple cells in a plan view of the tire side surface. The plurality of cells are arranged adjacent to each other, each having a concave polygon, and the concave and convex portions of the concave polygons are interlocked. A tire characterized in that the outer diameter Rm of the smallest inclusion circle of the cell is within the range of 0.05 [mm] ≤ Rm ≤ 5.00 [mm].

2. The tire according to claim 1, wherein the interior angle of the concave polygon of the cell is in the range of 50 degrees or more and 310 degrees or less.

3. The tire according to claim 1, wherein the ratio of the maximum value Sc_max to the minimum value Sc_min of the area Sc of the plurality of cells is in the range of 1.00 ≤ Sc_max / Sc_min ≤ 1.

60.

4. The tire according to claim 1, wherein the width W52B of the base of the ridge is in the range of 0.05 [mm] ≤ W52B ≤ 0.50 [mm].

5. The tire according to claim 1, wherein the plurality of cells have congruent concave polygons and are arranged with the orientation of the concave polygons irregularly varied.

6. The tire according to claim 1, wherein the ratio of the minimum and maximum side lengths of the concave polygon of the cell is in the range of 1.00 or more and 2.00 or less.

7. The tire according to claim 1, wherein the concave polygon of the plurality of cells is defined as a figure formed by arranging a plurality of hexagons in a close-packed structure, each of the plurality of hexagons being divided into six divisions by three imaginary lines passing through the midpoints of three pairs of opposite sides, and eight adjacent divisions being connected.

8. The tire according to claim 1, wherein each of the plurality of cells has three or more recesses and the three or more recesses are fitted into the other three cells.

9. The tire according to claim 1, wherein the distance Dc between opposing wall surfaces of the cell is in the range of 0.05 [mm] ≤ Dc ≤ 1.50 [mm].

10. The tire according to claim 1, wherein the ratio of the maximum and minimum values ​​of the outer diameter Rm of the smallest inclusion circle of the plurality of cells is in the range of 1.00 or more and 1.20 or less.

11. The tire side surface is provided with a mark portion and a surrounding area surrounding the mark portion. The mark portion includes the ridge region, and The tire according to claim 1, wherein the peripheral region is a smooth surface.

12. The tire side surface is provided with a mark portion and a surrounding area surrounding the mark portion. The mark portion is made of a smooth surface, and The tire according to claim 1, wherein the peripheral region includes the ridge region.

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