Tire

Abstract

This tire has a ridge region 5 provided on a tire side surface. The ridge region 5 is configured from a plurality of annular ridges 52 each having an annular structure in a planar view of the tire side surface. The plurality of annular ridges 52 include a plurality of ridge units each configured from one first annular ridge and a plurality of second annular ridges intersecting the one first annular ridge. The plurality of ridge units are continuously arranged so that adjacent ridge units share one or two of the plurality of second annular ridges.

Description

tire

[0001] The present invention relates to a tire, and more particularly to a tire that can improve the blackening performance and visual angle uniformity performance of a ridge region.

[0002] Recent tires have adopted a configuration in which a ridge region consisting of multiple ridges is used to blacken markings such as side brands, thereby improving their visibility. A known conventional tire employing such a configuration is the technology described in Patent Document 1. However, there is also the issue of making the blackening effect of the ridge region uniform when the tire side surface is viewed from different directions. A known conventional tire addressing this issue is the technology described in Patent Document 2.

[0003] European Patent Application Publication No. 3030432 Japanese Patent Application Laid-Open No. 2016-215700

[0004] An object of the present invention is to provide a tire that can improve the blackening performance and the visual angle uniformity performance of the ridge region.

[0005] In order to achieve the above-mentioned object, the tire of the present invention is a tire having a ridge region on the tire side surface, wherein the ridge region consists of a plurality of annular ridges having an annular structure when viewed in a plane on the tire side surface, the plurality of annular ridges include a plurality of ridge units each consisting of a first annular ridge and a plurality of second annular ridges intersecting the one first annular ridge, and the plurality of ridge units are arranged continuously so that adjacent ridge units share one or two of the plurality of second annular ridges with each other, or so that they intersect or connect with each other.

[0006] In the tire according to the present invention, (1) the tire includes a ridge region on the tire side surface, which results in a relatively higher light absorption rate in the ridge region than in other regions. This results in a relatively darker ridge region, creating a clearer contrast on the tire side surface. (2) The ridge region is composed of multiple annular ridges that have an annular structure in a plan view of the tire side surface, which promotes diffuse reflection of light between the ridges and improves the visual uniformity of the ridge region, i.e., the uniformity of the darkening effect of the ridge region when the tire side surface is viewed from different directions. (3) The multiple annular ridges include multiple ridge units each consisting of a first annular ridge and multiple second annular ridges intersecting the first annular ridge, and the multiple ridge units are arranged continuously. This increases the arrangement density of the annular ridges, improving the darkening effect of the ridge region and facilitating laser processing of the vulcanization molding die for forming the ridge region.

[0007] FIG. 1 is a cross-sectional view in the tire meridian direction showing a tire according to an embodiment of the present invention. FIG. 2 is a plan view showing a tire side portion of the tire shown in FIG. 1. FIG. 3 is an enlarged view showing a marking portion of the tire side portion shown in FIG. 2. FIG. 4 is an explanatory diagram showing a ridge region of the tire side portion shown in FIG. 2. FIG. 5 is an explanatory diagram showing a ridge region of the tire side portion shown in FIG. 2. FIG. 6 is an explanatory diagram showing a ridge region of the tire side portion shown in FIG. 2. FIG. 7 is an explanatory diagram showing a ridge region of the tire side portion shown in FIG. 2. FIG. 8 is an explanatory diagram showing a method of processing the ridge region shown in FIG. 5. FIG. 9 is an explanatory diagram showing a modified example of the ridge region shown in FIG. 5. FIG. 10 is an explanatory diagram showing a modified example of the ridge region shown in FIG. 5. FIG. 11 is an explanatory diagram showing a modified example of the ridge region shown in FIG. 5. FIG. 12 is an explanatory diagram showing a modified example of the ridge region shown in FIG. 5. FIG. 13 is an explanatory diagram showing a modified example of the ridge region shown in FIG. 5. FIG. 14 is an explanatory diagram showing a modified example of the ridge region shown in FIG. 5. Fig. 15 is an explanatory diagram showing a modified example of the ridge region shown in Fig. 5. Fig. 16 is an explanatory diagram showing a modified example of the ridge region shown in Fig. 5. Fig. 17 is an explanatory diagram showing a modified example of the ridge region shown in Fig. 5. Fig. 18 is an explanatory diagram showing a modified example of the ridge region shown in Fig. 5. Fig. 19 is a table showing the results of performance tests on tires according to embodiments of the present invention.

[0008] The present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to these embodiments. Furthermore, the components of these embodiments include those that can be substituted and are obvious substitutes while maintaining the identity of the invention. Furthermore, the multiple modifications described in these embodiments can be arbitrarily combined within the scope obvious 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, a pneumatic radial tire for passenger cars will be described as an example of a tire.

[0010] In the figure, the tire meridian cross section is defined as a cross section of the tire 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 section width defined by 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 edge, and point Ac is the tire's 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 Figure 1).

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

[0013] The carcass layer 13 has a single-layer structure consisting of one carcass ply or a multi-layer structure consisting of multiple carcass plies stacked together, and is toroidally laid between the left and right bead cores 11, 11 to form the tire framework. Both ends of the carcass layer 13 are wrapped back and secured outward in the tire width direction to encase the bead cores 11 and the bead fillers 12. The carcass ply of the carcass layer 13 is formed by coating multiple carcass cords made of steel or organic fiber material (e.g., aramid, nylon, polyester, rayon, etc.) with coating rubber and rolling them, and has a cord angle (defined as the inclination angle of the carcass cords in the longitudinal direction relative to the tire circumferential direction) of 80 degrees or more and 100 degrees or less.

[0014] The belt layer 14 is formed by laminating a plurality of belt plies 141 to 143, and is disposed by being wound around the outer periphery of the carcass layer 13. The belt plies 141 to 143 each include a pair of cross belts 141, 142 and a belt cover 143.

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

[0016] The belt cover 143 is formed by covering a belt cover cord made of steel or organic fiber material with coating rubber, and has a cord angle of 0 degrees or more and 10 degrees or less in absolute value. The belt cover 143 is, for example, a strip material formed by covering one or more belt cover cords with coating rubber, and is formed by winding this strip material spirally around the outer circumferential surfaces of the cross belts 141, 142 multiple times in the tire circumferential direction. The belt cover 143 is disposed to cover the entire area of ​​the cross belts 141, 142.

[0017] The tread rubber 15 is disposed on the radially outer periphery of the carcass layer 13 and the belt layer 14 to form the tread portion of the tire 1. The tread rubber 15 is made of a rubber material with excellent ground contact characteristics and weather resistance, and is exposed over the entire outer periphery of the tire to form the tread surface. A pair of sidewall rubbers 16, 16 are disposed on the outer sides of the carcass layer 13 in the tire width direction to form left and right sidewall portions. A pair of rim cushion rubbers 17, 17 extend from the radially inner sides of the left and right bead cores 11, 11 and the turned-up portions of the carcass layer 13 to the outer sides in the tire width direction to form the rim fitting surfaces of the bead portions.

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

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

[0020] The marking portion 2 includes a mark consisting of letters, figures, symbols, or a combination thereof, and particularly includes a trademark that functions as an identification sign indicating the tire manufacturer, tire brand, etc. Furthermore, multiple marking portions 2, 2 are arranged spaced apart in the tire circumferential direction. For example, in the configuration shown in Fig. 2, a mark consisting of a combination of the character string "YOKOHAMA" indicating the tire manufacturer and a logo with a stylized "Y," the initial letter of the name, is stamped on the surface of the tire side. Furthermore, a pair of marking portions 2, 2 are arranged in opposing positions in the tire circumferential direction.

[0021] 3, the radial height H2 of the elements 2A to 2E constituting the marking portion 2 is in the range of 0.05≦H2 / SH≦0.80 relative to the tire cross-sectional height SH, and preferably in the range of 0.10≦H2 / SH≦0.70. This improves the visibility of the marking portion 2.

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

[0023] The tire section height SH is the distance half the difference between the tire outer diameter and the rim diameter, and is measured with the tire mounted on a specified rim, with a specified internal pressure applied, and in an unloaded state.

[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 the "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 the "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, and the specified load is 88% of the maximum load capacity.

[0025] The peripheral region 3 is an area surrounding the marking portion 2 and is formed on the surface of the tire side portion. The peripheral region 3 may be a smooth surface having a smooth surface, or may be an uneven surface that has been subjected to a surface treatment.

[0026] For example, in the configuration of Fig. 2, the peripheral region 3 is a smooth, continuous, smooth surface without grooves or unevenness. The peripheral region 3 is disposed to surround the entire marking portion 2, thereby enhancing the visibility of the marking portion 2. The peripheral region 3 is formed between a pair of narrow ribs 41, 42 extending in the tire circumferential direction, thereby enhancing the design of the tire side portion. The single peripheral region 3 has an annular structure that extends around the entire circumference of the tire side portion, thereby surrounding the pair of marking portions 2, 2.

[0027] 2 , the marking portion 2 and the peripheral region 3 are disposed radially outward of the tire maximum width position Ac. More specifically, a pair of narrow ribs 41, 42 extending in the tire circumferential direction are disposed in the region from the tire ground contact edge T to the tire maximum width position Ac (see FIG. 1 ), and the marking portion 2 and the peripheral region 3 are disposed between these narrow ribs 41, 42. This improves the visibility of the marking portion 2. However, this is not limiting, and the marking portion 2 and the peripheral region 3 may be disposed so as to intersect with the tire maximum width position Ac or may be disposed radially inward of 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 section width.

[0029] The tire cross-sectional width is measured as the straight-line distance between the sidewalls, excluding any patterns or letters on the side of the tire, when the tire is mounted on a specified rim, pressurized to a specified internal pressure, and under no load.

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

[0031] The pair of thin ribs 41, 42 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 path for discharging residual air during tire vulcanization. This prevents vulcanization defects from occurring in the marking portion 2 and the surrounding area 3. In the configuration shown in Figure 2, the thin rib 41 on the outer diameter side is located at the mold split position of the tire molding die.

[0032] 3, the radial height H2 [mm] of the elements 2A to 2E constituting the marking portion 2, relative to the arrangement interval H4 [mm] of the thin ribs 41, 42 in the tire radial direction, is in the range of 0.30≦H2 / H4≦0.80, and preferably in the range of 0.40≦H2 / H4≦0.70. Also, as shown in FIG. 3, it is preferable that the marking portion 2 is arranged at a distance from the pair of thin ribs 41, 42. This improves the visibility of the marking portion 2.

[0033] [Ridge Region] Figures 4 to 7 are explanatory diagrams showing the ridge region 5 of the tire side portion shown in Figure 2. In these figures, Figure 4 shows one element 2A constituting the marking portion 2 shown in Figure 3, Figure 5 is an enlarged plan view showing a portion of the ridge region 5 shown in Figure 4, Figure 6 is an enlarged view showing a single ridge unit U, and Figure 7 is a cross-sectional view showing the ridge region 5 shown in Figure 5. Here, as an example, a configuration in which the marking portion 2 is made up 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 a plurality of annular ridges 52 .

[0035] The housing 51 is a frame-shaped recess formed in the tire side surface, and in a plan view of the tire side, forms the outline of the marking portion 2. The depth H51 of the housing 51 (see FIG. 7) 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 the peripheral region 3 in FIG. 7) to the bottom surface of the housing 51.

[0037] As shown in Fig. 7, the annular ridge 52 is a rib-like convex portion protruding from the bottom surface of the housing 51, and has a cross-sectional shape that narrows toward the top. Also, as shown in Fig. 5, a plurality of the annular ridges 52 are arranged in a predetermined direction and filled into the housing 51. The planar shape and arrangement pattern of the annular ridges 52 will be described in detail later.

[0038] For example, in the configuration of FIG. 3, the marking portion 2 is formed by a ridge region 5 as shown in FIG. 4. Specifically, the logo 2A constituting the marking portion 2 is composed of a combination of multiple thin lines arranged in parallel. The outlines of these thin lines are formed by the edge portions of the housing 51 (see FIG. 7), which will be described later. Similarly, other components constituting the marking portion 2 (e.g., elements 2B to 2E in FIG. 3) are composed of thick lines representing letters, and the outlines of the thick lines are formed by the edge portions of the housing 51 (not shown). Also, as shown in FIG. 7, multiple annular ridges 52 have uniform trapezoidal or triangular cross sections. The multiple annular ridges 52 are arranged in a predetermined arrangement pattern within the housing 51, filling the entire area of ​​the housing 51. As a result, the marking portion 2 is represented by the housing 51 and the multiple annular ridges 52.

[0039] In the above configuration, the tire side surface includes a ridge region 5 formed by an arrangement of multiple annular ridges 52, so that in a plan view of the tire side portion, the light absorption rate in the ridge region 5 (marking portion 2 in FIG. 3 ) is relatively higher than the light absorption rate in other regions (peripheral region 3 in FIG. 3 ). This makes the ridge region 5 relatively black, providing a clear contrast to the tire side surface and improving the visibility of the tire side surface.

[0040] In the configuration shown in FIG. 7 , the height H52 of the annular ridge 52, relative to the depth H51 of the housing 51, is in the range of 0.30≦H52 / H51<1.00, and preferably in the range of 0.50≦H52 / H51≦0.95. Therefore, the top of the annular ridge 52 is embedded within the housing 51. This configuration is preferable because it suppresses deterioration of air resistance at the tire side portion due to the annular ridge 52 protruding from the tire side surface. However, this is not limited thereto. The height H52 of the annular ridge 52 may also protrude from the tire side surface (not shown) by having the height H52 of the annular ridge 52, relative to the depth H51 of the housing 51, be in the range of 1.00≦H52 / H51. This configuration facilitates application of wax to the top of the annular ridge 52, improving wax retention on the tire side surface.

[0041] The height H52 of the annular ridge 52 is defined as the distance from the top of the annular ridge 52 to the bottom surface of the housing 51, as shown in Figure 7, and specifically, is measured as the distance from the top of the annular ridge 52 to the bottom of the valley between adjacent annular ridges 52, 52.

[0042] 7, the width W52A of the top of the annular ridge 52, relative to the width W52B of the base of the annular ridge 52, is in the range of 0≦W52A / W52B≦0.90, and preferably in the range of 0.10≦W52A / W52B≦0.70. The lower limit prevents deterioration in the processability of the annular ridge 52 due to the top of the annular ridge 52 being too thin, and the upper limit improves the blackening effect of the annular ridge 52 on the tire side surface.

[0043] The widths W52A and W52B of the annular ridge 52 are measured as the width in a cross section perpendicular to the longitudinal direction of the annular ridge 52. The width W52B of the base of the annular ridge 52 is defined as the width of the bottom surface of the annular ridge 52 (in FIG. 7 , the contact surface between the base of the annular ridge 52 and the bottom surface of the housing 51), and is specifically measured as the distance between imaginary lines connecting the valley bottoms of adjacent annular ridges 52, 52.

[0044] 2, as described above, the ridge region 5 is composed of a housing 51 and a plurality of annular ridges 52 arranged within the housing 51 (see FIGS. 5 and 7). However, this is not limiting, and the housing 51 may be omitted, and the ridge region 5 may be composed only of a plurality of annular ridges 52 (not shown). For example, the plurality of annular ridges 52 may protrude from the same plane as the peripheral region 3. Even with such a configuration, the visibility of the marking portion 2 can be improved.

[0045] 2, the peripheral region 3 is a smooth surface. This configuration is preferable because it improves the visibility of the marking portion 2, which is composed of the housing 51 and the multiple annular ridges 52. However, the configuration is not limited to this, and the peripheral region 3 may also be a textured surface with a surface treatment (not shown). The textured surface may be formed by arranging multiple uneven portions, for example, multiple longitudinal ridges or multiple grooves, or multiple hemispherical or conical protrusions or multiple depressions.

[0046] 5, the ridge region 5 is made up of a plurality of annular ridges 52. The annular ridges 52 have an annular structure in a plan view of the tire side surface. The plurality of annular ridges 52 are repeatedly arranged in a predetermined arrangement pattern in the planar direction of the tire side portion.

[0047] The annular structure is defined as a structure formed by connecting both ends of a linear or longitudinal shape to each other in a plan view of the tire side surface, and is not limited to a continuous annular structure around the entire circumference, but also includes a substantially annular structure having a minute separation of less than 0.50 mm, preferably less than 0.40 mm.

[0048] It is also preferred that the annular ridge 52 has a circular, elliptical or rounded regular polygonal shape, i.e., the annular ridge 52 has a smooth annular structure without corners.

[0049] When the annular ridge 52 is elliptical, the ratio of the length of the major axis to the length of the minor axis is 1.00 or greater and 3.00 or less, and preferably 1.00 or greater and 1.41 or less.

[0050] A rounded regular polygon is defined as a polygon in which the vertices of a convex polygon are rounded in an R-shape. The ratio of the maximum to minimum side length is 1.00 to 5.00, preferably 1.00 to 4.00. The ratio of the maximum to minimum interior angle is 1.00 to 5.00, preferably 1.00 to 4.00. The R-shape is formed by rounding a range of 40% to 90%, preferably 50% to 85%, of the side length from each vertex of a reference polygon.

[0051] The rounded regular polygon also includes a substantially rounded polygon formed by approximating its straight line segments to arcs. Specifically, the substantially rounded polygon is formed by replacing the straight line segments of the rounded regular polygon with arcs that convex outward in the radial direction of the annular ridge 52, and smoothly connecting these arcs with the R-shaped arcs located at the vertices of the convex polygon. Therefore, the entire substantially rounded polygon is formed by connecting multiple arcs that convex outward in the radial direction of the annular ridge 52 and have different radii.

[0052] Furthermore, the ratio of the maximum value Rm_max to the minimum value Rm_min of the outer diameter Rm of the smallest encompassing circle (not shown) of the annular ridge 52, i.e., the smallest circle encompassing the annular ridge 52, is in the range of 1.00≦Rm_max / Rm_min≦1.20, and preferably 1.00≦Rm_max / Rm_min≦1.05. Therefore, the annular ridge 52 has a substantially uniform size. Furthermore, the outer diameter Rm of the smallest encompassing circle of the annular ridge 52 is in the range of 0.80 mm≦Rm≦20.0 mm, preferably 1.00 mm≦Rm≦10.00 mm, and more preferably 1.20 mm≦Rm≦3.00 mm.

[0053] 6, the plurality of annular ridges 52 include a plurality of ridge units U each consisting of a first annular ridge 52P and a plurality of second annular ridges 52Q intersecting the first annular ridge 52P. That is, each of the plurality of second annular ridges 52Q intersects one of the first annular ridges 52P.

[0054] Furthermore, the center points (reference numerals omitted in the drawing) of the plurality of second annular ridges 52Q are disposed outside the first annular ridge 52P (see FIG. 6) or on the first annular ridge 52P.

[0055] Preferably, three or more, more preferably three, four, or six, second annular ridges 52Q intersect one first annular ridge 52P. In this case, the three or more second annular ridges 52Q are arranged point-symmetrically about the center point of the first annular ridge 52P, i.e., in different directions from each other. Specifically, the three or more second annular ridges 52Q are arranged at a predetermined spacing θ [deg] (see FIG. 6 ) around the circumferential direction of the first annular ridge 52P, and the ratio θ_max / θ_min of the maximum spacing θ_max to the minimum spacing θ_min of the three or more second annular ridges 52Q is in the range of 1.00≦θ_max / θ_min≦1.50, preferably 1.00≦θ_max / θ_min≦1.30. This results in the second annular ridges 52Q being arranged in a dispersed manner, improving the viewing angle uniformity of the ridge region 5.

[0056] The center point of the annular ridge 52 is defined as the center point of the smallest encompassing circle of the annular ridge 52 .

[0057] As shown in FIG. 6, the arrangement interval θ [deg] of the second annular ridges 52Q is defined as the angle formed by an imaginary line passing through the center point of adjacent second annular ridges 52Q and the center point of the first annular ridge 52P.

[0058] Furthermore, the multiple ridge units U are arranged continuously without any space between them, thereby continuously arranging the multiple annular ridges 52 and filling the ridge region 5. Furthermore, the first and second annular ridges 52P, 52Q that make up the multiple ridge units U have the same shape and size, which makes it possible to efficiently achieve a continuous arrangement of the multiple ridge units U.

[0059] For example, in the configuration of FIG. 5 , adjacent ridge units U, U (reference numerals omitted in the figure) are arranged so as to share one or two of the multiple second annular ridges 52Q (see FIG. 6 ). Specifically, as shown in FIG. 6 , a first ridge unit U is defined, consisting of one first annular ridge 52P and multiple second annular ridges 52Q intersecting the first annular ridge 52P. Similarly, a second ridge unit U (not shown) is defined, consisting of one first annular ridge 52P and multiple second annular ridges 52Q. Then, as shown in FIG. 5 , the first and second ridge units U, U (reference numerals omitted in the figure) are arranged adjacent to each other so as to share one or two of the multiple second annular ridges 52Q. Then, by sequentially defining and arranging multiple ridge units U in the same manner, the multiple annular ridges 52 are connected in the planar direction, filling the entire ridge region 5. This forms a ridge region 5 consisting of multiple mutually intersecting annular ridges 52, as shown in FIG. 5 . Furthermore, adjacent ridge units U, U are arranged so that the first annular ridges 52P, 52P are connected to each other, thereby allowing the multiple annular ridges 52 to be arranged in a close-packed structure.

[0060] Furthermore, without being limited to the above, adjacent ridge units U, U may be arranged such that portions of the multiple second annular ridges intersect or connect with each other (not shown).Furthermore, adjacent ridge units U, U may be arranged such that the first annular ridges 52P, 52P are spaced apart from each other (not shown).

[0061] In the above configuration, (1) because the tire 1 includes a ridge region 5 on the tire side surface, the light absorption rate in the ridge region 5 (marking portion 2 in FIG. 3 ) is relatively higher than the light absorption rate in other regions (peripheral region 3 in FIG. 3 ). This results in a relatively darker ridge region 5, creating a clearer contrast on the tire side surface. Furthermore, (2) because the ridge region 5 is composed of multiple annular ridges 52 each having an annular structure in a plan view of the tire side surface, the diffuse reflection of light between the ridges is promoted, improving the visual angle uniformity of the ridge region 5, i.e., the uniformity of the darkening effect of the ridge region 5 when the tire side surface is viewed from different directions. Furthermore, (3) because the multiple annular ridges 52 include multiple ridge units U, each of which is composed of one first annular ridge 52P and multiple second annular ridges 52Q intersecting the first annular ridge 52P, and the multiple ridge units U are arranged continuously, the arrangement density of the annular ridges 52 is increased, improving the darkening effect of the ridge region 5 and facilitating laser processing of the vulcanization molding die for forming the ridge region 5.

[0062] For example, in the configuration shown in FIG. 5 , a single annular ridge 52 has a circular shape in a plan view of the tire side surface. Also, as shown in FIG. 6 , one ridge unit U consists of one first annular ridge 52P and four second annular ridges 52Q. Each of the four second annular ridges 52Q intersects with one first annular ridge 52P. The four second annular ridges 52Q are arranged point-symmetrically around the first annular ridge 52P and intersect with the first annular ridge 52P. The four second annular ridges 52Q are connected in a circular grid pattern. As shown in FIG. 5 , multiple ridge units U (reference numerals omitted; see FIG. 6 ) are arranged in the planar direction of the tire side surface. The multiple ridge units U are repeatedly arranged vertically and horizontally, with adjacent ridge units U, U sharing one or two second annular ridges 52Q. As a result, the multiple annular ridges 52 are arranged vertically and horizontally in a chain-like intersecting pattern, filling the ridge region 5. The number of second annular ridges 52Q shared by adjacent ridge units U, U differs depending on which of the multiple annular ridges 52 in FIG. 5 is defined as the first annular ridge 52P.

[0063] 5 defines a plurality of cells C1 and C2 partitioned by a plurality of annular ridges 52, as shown in Fig. 6. Specifically, in one ridge unit U, a first annular ridge 52P and a plurality of second annular ridges 52Q intersect with each other, thereby forming a plurality of cells C1 and C2 inside the first annular ridge 52P.

[0064] In this case, the ratio of the maximum value Sc_max to the minimum value Sc_min of the area S (not shown) of these cells C1, C2 is in the range of 1.00≦Sc_max / Sc_min≦1.60, and preferably in the range of 1.00≦Sc_max / Sc_min≦1.20, thereby making the areas of the multiple cells C1, C2 uniform and uniformly blackening the ridge region 5.

[0065] The area Sc of the cells C1 and C2 is measured as the area of ​​a closed region surrounded by the wall surface of the annular ridge 52Q in a plan view of the tire side portion.

[0066] 5, the maximum value Dc_max of the distance Dc (Dc1, Dc2) between the opposing wall surfaces of the plurality of cells C1, C2 partitioned by the plurality of annular ridges 52 is in the range of 0.10 mm≦Dc_max≦1.10 mm, and preferably in the range of 0.20 mm≦Dc_max≦0.80 mm, as shown in FIG. 6. The lower limit ensures that the opposing wall surfaces of the annular ridge 52 have a gap to absorb light, while the upper limit ensures that the light absorption rate in the distance between the opposing wall surfaces is maintained, thereby ensuring the blackening effect of the ridge region 5.

[0067] The distance Dc (Dc1, Dc2) between the opposing wall surfaces is measured as the distance between the center lines of the annular ridges 52 in a plan view of the multiple cells C1, C2 partitioned by the annular ridges 52. When the cells C1, C2 have a longitudinal shape, the distance between the opposing wall surfaces is measured as the distance between the center lines of the annular ridges 52 in a direction perpendicular to the longitudinal direction. However, in a configuration in which adjacent ridges have a partial connection, the separation distance Dc is measured excluding this connection.

[0068] 6, the distance Dr2 between the opposing wall surfaces of adjacent second annular ridges 52Q, 52Q among the multiple second annular ridges 52Q is in the range of 0 mm≦Dr2≦1.10 mm, and preferably in the range of 0 mm≦Dr2≦0.80 mm. This upper limit ensures the light absorption rate at the distance between the opposing wall surfaces of the annular ridge 52, thereby ensuring the blackening effect of the ridge region 5. In the configuration of FIG. 6, adjacent second annular ridges 52Q, 52Q are connected to each other in an annular shape, so the distance Dr2 between the opposing wall surfaces is 0 mm.

[0069] The distance Dr2 between the opposing wall surfaces is measured as the distance between the center lines of adjacent second annular ridges 52Q, 52Q in a plan view. Furthermore, when adjacent second annular ridges 52Q, 52Q intersect to define cells, the distance between the opposing wall surfaces is measured as the distance between the center lines of adjacent second annular ridges 52Q, 52Q in a direction perpendicular to the longitudinal direction of the cell. However, in configurations where adjacent ridges have a partial connection, the distance Dr2 is measured excluding this connection.

[0070] [Tire Manufacturing Method] The tire 1 is manufactured using a tire molding die capable of transferring the above-described ridge region 5 onto the tire side surface.

[0071] Specifically, the tire 1 is manufactured, for example, by the following manufacturing process. First, tire components such as bead wires that form the bead cores, carcass plies that form the carcass layer, belt plies that form the belt layer, tread rubber, sidewall rubber, and rim cushion rubber are placed in a molding machine to form a green tire (not shown). Next, the green tire is loaded into a tire vulcanization mold (not shown) that includes a tire molding die. Next, the green tire is expanded radially outward by a pressure device and abuts against the tire molding die. Next, the tire vulcanization mold is heated, causing rubber molecules and sulfur molecules in the green tire to bond and vulcanization to proceed. At this time, the shape of the molding surface of the tire molding mold is transferred to the outer peripheral surface of the green tire, thereby forming the tire side surface. Then, the tire after vulcanization is pulled out and removed from the tire vulcanization mold.

[0072] The ridge region 5 on the tire side surface is formed by an uneven portion formed on the molding surface of the tire mold. The uneven portion on the molding surface of the tire mold is formed by, for example, laser processing.

[0073] FIG. 8 is an explanatory diagram showing a method for processing the ridge region 5 shown in FIG.

[0074] 5, all of the annular ridges 52 are arranged in a chain-like pattern, intersecting each other, filling the ridge region 5. This configuration is preferable because, when processing the molding surface of a tire mold, the uneven portion for forming the ridge region 5 can be formed in a single stroke using laser processing. The single stroke referred to here does not mean a strict single stroke, but rather means that the uneven portion can be processed without turning the laser on and off in the center of the ridge region 5. For this reason, the laser may pass through the same path.

[0075] Specifically, when forming the uneven portion for forming the ridge region 5 shown in Fig. 5, laser processing is performed on the molding surface of a tire molding die according to the procedure shown in Fig. 8. That is, laser processing is performed by moving the laser back and forth so that the ridge portion (L1) represented by the solid line in Fig. 8 is the outgoing path and the ridge portion (L2) represented by the dashed line is the returning path. As a result, one annular ridge 52 is formed in two parts by the outgoing and returning paths. At this time, all of the annular ridges 52 are arranged in a chain-like intersecting pattern, so that the uneven portion can be processed in the center of the ridge region 5 without turning the laser on and off.

[0076] 9 to 12 are explanatory diagrams showing modified examples of the ridge region 5 shown in Fig. 5. Like Fig. 6, these figures show enlarged views of a single ridge unit U. In these figures, the same components as those shown in Fig. 5 and Fig. 6 are given the same reference numerals, and their description will be omitted.

[0077] In the configuration of Fig. 5, the annular ridge 52 has a perfect circular shape, as shown in Fig. 6. This configuration is preferable in that it allows a high degree of freedom in the arrangement of the annular ridge 52.

[0078] However, the present invention is not limited to this. As described above, the annular ridge 52 may have an elliptical shape, a rounded regular polygon shape, or a shape formed by connecting multiple types of arcs with different curvatures. For example, in the modified example shown in Figure 9, the annular ridges 52 constituting the ridge unit U have rounded regular quadrilateral shapes, thereby making the areas of the multiple cells C1 and C2 defined by the multiple annular ridges 52 uniform. In particular, the areas of the cells C1 and C2, which have different shapes, are made uniform. This configuration is preferable in that the ridge region 5 is uniformly blackened.

[0079] 5, as shown in FIG. 6, multiple second annular ridges 52Q intersecting one first annular ridge 52P are connected to each other in a circular configuration. Therefore, the distance Dr2 between the opposing wall surfaces of adjacent second annular ridges 52Q, 52Q is 0 mm. This configuration is advantageous in that it allows efficient laser processing when processing the uneven portion for forming the ridge region 5 on the molding surface of the tire mold, for example, by laser processing the uneven portion in a single stroke (see FIG. 8).

[0080] However, this is not limiting. As shown in Figures 10 and 11, multiple second annular ridges 52Q intersecting a single first annular ridge 52P may be spaced apart from one another. In the configurations shown in Figures 10 and 11, all four second annular ridges 52Q are spaced apart from one another. Furthermore, the distance Dr2 between the opposing wall surfaces of adjacent second annular ridges 52Q, 52Q is optimized within the above-described range. Even with this configuration, the blackening effect of the ridge region 5 is ensured.

[0081] 5, four second annular ridges 52Q intersect with one first annular ridge 52P to form one ridge unit U, as shown in Fig. 6. In this configuration, the four second annular ridges 52Q can be arranged in a lattice pattern while being connected to each other in an annular shape, which is preferable in that the areas of the cells C1 and C2 partitioned by the annular ridge 52 can be efficiently made uniform by using an annular ridge 52 having a rounded square shape, as in the modified example shown in Fig. 9.

[0082] However, this is not a limitation, and as shown in FIGS. 12 and 13 , one ridge unit U may be formed by three second annular ridges 52Q (see FIG. 13 ) intersecting one first annular ridge 52P. Specifically, in the configuration of FIG. 12 , as shown in FIG. 13 , three second annular ridges 52Q are connected to each other in a truss shape and arranged to surround one first annular ridge 52P. As shown in FIG. 12 , adjacent ridge units U, U (reference numerals omitted in the figure) share one second annular ridge 52Q and are arranged such that the first annular ridges 52P are connected to each other. Multiple ridge units U are then repeatedly arranged to fill the ridge region 5. As a result, multiple annular ridges 52 are arranged in a close-packed structure, intersecting each other in a chain-like manner.

[0083] 14 and 15, six second annular ridges 52Q (see FIG. 15) may intersect one first annular ridge 52P to form one ridge unit U. Specifically, in the configuration of FIG. 14, as shown in FIG. 15, six second annular ridges 52Q are arranged in a ring shape while sharing the center of one first annular ridge 52P and intersect the first annular ridge 52P. Adjacent second annular ridges 52Q also intersect with each other. As shown in FIG. 15, adjacent ridge units U, U (reference numerals omitted in the figure) share two second annular ridges 52Q with each other and are arranged such that the first annular ridges 52P are connected to each other. Multiple ridge units U are arranged repeatedly to fill the ridge region 5. As a result, multiple annular ridges 52 are arranged in a close-packed structure, intersecting in a chain-like manner. In the configuration of FIG. 14, adjacent ridge units U, U have their two second annular ridges 52Q intersecting with the other first annular ridge 52P. 15, the first annular ridge 52P is divided into a total of 18 cells C1 to C3 by its own second annular ridge 52Q and the second annular ridges (broken lines in the figure: reference numerals omitted) of the adjacent ridge units U. Furthermore, these cells C1 to C3 have approximately the same area.

[0084] Also, as shown in Figures 16 and 17, one ridge unit U may be formed by five (Figure 16) or eight (Figure 17) second annular ridges 52Q intersecting one first annular ridge 52P.

[0085] 2, as described above, the marking portion 2 is made up of the ridge region 5, and the peripheral region 3 surrounding the marking portion 2 is made up of a smooth surface. This configuration is preferable in that the marking portion 2 is colored black, improving the visibility of the marking portion 2.

[0086] 18, the symbol portion 2 is made of a smooth surface, and the peripheral region 3 surrounding the symbol portion 2 is made of a ridge region 5. Specifically, the ridge region 5 is made up of a housing 51 (not shown; see FIG. 7) that surrounds the outline of the symbol portion 2 within an area defined by a pair of thin ribs 41, 42, and a plurality of annular ridges 52 arranged on this housing 51. In this configuration, the peripheral region 3 is blackened, and the symbol portion 2 appears with an appearance in reverse contrast.

[0087] [Effects] As described above, [1] this tire 1 includes a ridge region 5 on the tire side surface (see FIGS. 1 to 4). The ridge region 5 is made up of a plurality of annular ridges 52 that have an annular structure in a plan view of the tire side surface (see FIG. 5). The plurality of annular ridges 52 include a plurality of ridge units U (see FIG. 6), each of which is made up of a first annular ridge 52P and a plurality of second annular ridges 52Q that intersect with the first annular ridge 52P. The plurality of ridge units U are arranged continuously such that adjacent ridge units U share one or two of the plurality of second annular ridges 52Q (see FIG. 5), or intersect or connect with each other (not shown).

[0088] In the above configuration, (1) because the tire 1 includes a ridge region 5 on the tire side surface, the light absorption rate in the ridge region 5 (marking portion 2 in FIG. 3 ) is relatively higher than the light absorption rate in other regions (peripheral region 3 in FIG. 3 ). This has the advantage of relatively darkening the ridge region 5 and creating a clear contrast on the tire side surface. Furthermore, (2) because the ridge region 5 is made up of multiple annular ridges 52 that have an annular structure in a plan view of the tire side surface, the diffuse reflection of light between the ridges is promoted, which has the advantage of improving the visual angle uniformity of the ridge region 5, i.e., the uniformity of the blackening effect of the ridge region 5 when the tire side surface is viewed from different directions. Furthermore, (3) since the multiple annular ridges 52 include multiple ridge units U each consisting of one first annular ridge 52P and multiple second annular ridges 52Q intersecting the first annular ridge 52P, and the multiple ridge units U are arranged continuously, the arrangement density of the annular ridges 52 is increased, improving the blackening effect of the ridge region 5, and there is also the advantage that laser processing of the vulcanization molding mold for forming the ridge region 5 is made easier.

[0089] [2] In addition, in the tire 1 described in [1] above, three, four, or six second annular ridges 52Q intersect one first annular ridge 52P (see FIGS. 6, 13, and 15), which has the advantage of efficiently realizing a continuous arrangement of multiple ridge units U.

[0090] [3] In the tire 1 according to the above [1] or [2], the annular ridge 52 has a circular, elliptical, or rounded regular polygonal shape. This configuration has the advantage of promoting diffused reflection of light between the ridges and improving the visual angle uniformity of the ridge region 5, compared to a configuration (not shown) in which the annular ridge 52 has an angular shape.

[0091] [4] In the tire 1 according to any one of the above [1] to [3], the ratio of the maximum value Sc_max to the minimum value Sc_min of the area S of the plurality of cells C1, C2 (see FIG. 6 ) partitioned by the plurality of annular ridges 52 is in the range of 1.00≦Sc_max / Sc_min≦1.60. As a result, the areas of the plurality of cells C1, C2 are uniformed, and the ridge region 5 is uniformly blackened.

[0092] [5] In the tire 1 according to any one of the above [1] to [4], the maximum value Dc_max of the distance Dc (Dc1, Dc2; see FIG. 6 ) between the opposing wall surfaces of the plurality of cells C1, C2 partitioned by the plurality of annular ridges 52 is in the range of 0.10 mm≦Dc_max≦1.10 mm. This has the advantage that the widths of the plurality of cells C1, C2 are uniform, and the ridge region 5 is uniformly blackened.

[0093] [6] In addition, in the tire 1 according to any one of the above [1] to [5], the plurality of second annular ridges 52Q intersecting one first annular ridge 52P are arranged so as to intersect with one another in an annular shape (see, for example, FIG. 15) or to be connected to one another (see, for example, FIGS. 6 and 13). This configuration has the advantage that when processing the uneven portion for forming the ridge region 5 on the molding surface of the tire mold, the processing can be performed efficiently by laser processing, for example, the uneven portion can be laser processed in a single stroke.

[0094] [7] The tire 1 is the tire 1 described in any one of [1] to [6] above, wherein adjacent ridge units U, U (see FIGS. 6, 13, and 15) share one or two of the plurality of second annular ridges 52Q with each other and are arranged such that the first annular ridges 52P are connected to each other (see FIGS. 5, 12, and 14), which has the advantage of allowing the plurality of annular ridges 52 to be arranged in a close-packed structure.

[0095] [8] The tire 1 is the tire 1 described in any one of [1] to [7] above, wherein the second annular ridges 52Q are arranged at a predetermined spacing θ [deg] around the circumferential direction of the first annular ridge 52P, and the ratio θ_max / θ_min of the maximum spacing θ_max to the minimum spacing θ_min of the second annular ridges 52Q is in the range 1.00≦θ_max / θ_min≦1.50. This has the advantage of dispersing the second annular ridges 52Q and improving the visual angle uniformity of the ridge region 5.

[0096] [9] In the tire 1 according to any one of the above [1] to [8], the ratio of the maximum value Rm_max to the minimum value Rm_min of the outer diameter Rm (see FIG. 6) of the smallest including circle of the plurality of annular ridges 52Q is in the range of 1.00≦Rm_max / Rm_min≦1.20, which has the advantage that the ridge region 5 is uniformly blackened.

[0097]

[10] In the tire 1 according to any one of the above items [1] to [9], the outer diameter Rm (see FIG. 6 ) of the smallest encompassing circle of the plurality of annular ridges 52 is in the range of 0.80 mm≦Rm≦20.0 mm. The lower limit ensures the processability of the annular ridges 52, while the upper limit has the advantage of ensuring the arrangement density of the annular ridges 52 in the ridge region 5.

[0098]

[11] The tire 1 is the tire 1 according to any one of [1] to

[10] above, further comprising a marking portion 2 and a peripheral region 3 surrounding the marking portion 2 on the tire side surface (see FIG. 2). The marking portion 2 includes a ridge region 5, and the peripheral region 3 is made of a smooth surface. This provides the advantage of blackening the marking portion 2 and improving its visibility.

[0099]

[12] The tire 1 is the tire 1 according to any one of the above [1] to

[10] , and includes a marking portion 2 and a peripheral region 3 surrounding the marking portion 2 on the tire side surface (see FIG. 18 ). The marking portion 2 has a smooth surface, and the peripheral region 3 includes a ridge region 5. In this configuration, the peripheral region 3 is colored black, and the marking portion 2 appears with an appearance in which the contrast is reversed.

[0100] [Applicable Objects] In this embodiment, as described above, a pneumatic tire has been described as an example of a tire. However, the present invention is not limited to this, and the configuration described in this embodiment can be applied to other tires as desired within the scope of what is obvious to those skilled in the art. Examples of other tires include airless tires and solid tires.

[0101] FIG. 19 is a table showing the results of performance tests of the tire according to the embodiment of the present invention.

[0102] In this performance test, several types of test tires were evaluated for (1) the blackening performance of the ridge region and (2) the visual angle uniformity performance of the ridge region. Also, a test tire having a tire size of 255 / 35R19 (96Y) was mounted on a rim having a rim size of 19x9J, and an internal pressure specified by JATMA was applied to this test tire.

[0103] (1) In the evaluation of the visibility of the marking, an inspector visually inspects the tire side of the test tire from a distance of 5 m and performs a sensory evaluation of the visibility of the ridge region, particularly the degree of blackening of the ridge region (contrast with the surrounding area). This evaluation is performed using an index evaluation with the comparative example as the standard (100), and the higher the value, the better.

[0104] (2) In the evaluation of the visual angle uniformity performance of the ridge region, an inspector visually inspects the tire side of the test tire from a distance of 5 m while rotating it by 120 degrees at a time, and performs a sensory evaluation of the visibility of the ridge region, particularly whether the degree of blackening of the ridge region is uniform. This evaluation is performed using an index evaluation with the comparative example as the standard (100), and the higher the value, the better.

[0105] The test tire of the example has the configuration shown in Figures 1 to 4 and 7, and the marking portion 2 is composed of a ridge region 5 formed by an arrangement of multiple annular ridges 52. All of the annular ridges 52 have the same shape and the same outer diameter Rm. Multiple ridge units U are arranged in succession, with adjacent ridge units U, U sharing one or two second annular ridges 52Q. The depth H51 of the housing 51 (see Figure 7) is H51 = 0.80 mm, and the height H52, top width W52A, and base width W52B of the annular ridge 52 are H52 = 0.50 mm, W52A = 0.10 mm, and W52B = 0.37 mm.

[0106] In the comparative example test tire, the ridge region of the example test tire was formed by arranging a plurality of ridges that were linear in plan view in parallel (not shown), and the pitch length between adjacent ridges was 1.10 mm.

[0107] As the test results show, the test tires of the examples have improved blackening performance in the ridge area and visual angle uniformity performance.

[0108] 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 marking portion; 3 peripheral region; 5 ridge region; 41, 42 narrow ribs; 51 housing; 52, 52P, 52Q annular ridge; C1, C2 cell; U ridge unit

Claims

1. A tire having a ridge region on its side surface, wherein the ridge region is made up of a plurality of annular ridges having an annular structure in a plan view of the side surface, the plurality of annular ridges including a plurality of ridge units each consisting of a first annular ridge and a plurality of second annular ridges intersecting the first annular ridge, and the plurality of ridge units are arranged consecutively such that adjacent ridge units share one or two of the second annular ridges with each other, or intersect or connect with each other.

2. The tire of claim 1, wherein three, four or six of said second annular ridges intersect said one first annular ridge.

3. A tire according to claim 1 or 2, wherein said annular ridge has a circular, elliptical or rounded regular polygonal shape.

4. A tire according to any one of claims 1 to 3, wherein the ratio of the maximum value Sc_max to the minimum value Sc_min of the area S of the cells partitioned by the annular ridges is in the range of 1.00≦Sc_max / Sc_min≦1.

60.

5. A tire according to any one of claims 1 to 4, wherein the maximum value Dc_max of the distance Dc between the opposing wall surfaces of the plurality of cells partitioned by the plurality of annular ridges is in the range of 0.10 mm≦Dc_max≦1.10 mm.

6. A tire according to any one of claims 1 to 5, wherein the plurality of second annular ridges intersecting one first annular ridge are arranged so as to intersect or be connected to one another in an annular shape.

7. A tire according to any one of claims 1 to 6, wherein the adjacent ridge units share one or two of the plurality of second annular ridges with each other and are arranged so as to interconnect the first annular ridges.

8. A tire as recited in any one of claims 1 to 7, wherein the second annular ridges are arranged at a predetermined spacing θ [deg] around the circumferential direction of the first annular ridge, and the ratio θ_max / θ_min of the maximum spacing θ_max to the minimum spacing θ_min of the second annular ridges is in the range of 1.00≦θ_max / θ_min≦1.

50.

9. A tire according to any one of claims 1 to 8, wherein the ratio of the maximum value Rm_max to the minimum value Rm_min of the outer diameter Rm of the smallest encompassing circle of said plurality of annular ridges is in the range of 1.00≦Rm_max / Rm_min≦1.

20.

10. A tire according to any one of claims 1 to 8, wherein the outer diameter Rm of the smallest encompassing circle of the plurality of annular ridges is in the range of 0.80 mm≦Rm≦20.0 mm.

11. A tire according to any one of claims 1 to 10, comprising a marking portion and a peripheral area surrounding said marking portion on said tire side surface, said marking portion including said ridge area, and said peripheral area consisting of a smooth surface.

12. A tire according to any one of claims 1 to 10, comprising a marking portion and a peripheral region surrounding said marking portion on said tire side surface, said marking portion consisting of a smooth surface, and said peripheral region including said ridge region.

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