Tire

Abstract

To provide a tire in which visibility of a pattern part can be improved.SOLUTION: The tire comprises a pattern part 4 in which a plurality of ridges 7 are arranged in parallel on a tire surface 5A. The pattern part 4 has a plurality of wave-like ridges 7A extending in a predetermined direction while amplifying in a wave-like fashion. The plurality of wave-like ridges 7A are arranged in parallel in a direction of the oscillation, and the adjacent wave-like ridges 7A are arranged so that amplitude phases of the adjacent wave-like ridges 7 deviate from each other. This enables the pattern part 4 to have a crude density of the ridges 7, which can enhance a degree of impression of the pattern part 4 visually recognized.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a tire, and more particularly to a tire that can improve the visibility of a pattern portion. [Background technology]

[0002] Some conventional tires have a pattern portion formed on the surface of the tire side portion, which is composed of a plurality of protrusions, to improve the visibility of the pattern portion.For example, the tire described in Patent Document 1 has a decorative pattern portion formed on the tire surface, which includes a plurality of first protrusions extending in a first direction and arranged at intervals in a second direction perpendicular to the first direction, and a plurality of second protrusions arranged at intervals in the first direction between adjacent first protrusions, and the first protrusions have a shape that oscillates in the second direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-215697 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even if multiple first projections are arranged at intervals, if the projections are arranged at regular intervals, the pattern tends to become monotonous and the contrast of the pattern portion is reduced, so it is desirable to further improve visibility.

[0005] The present invention has been made in view of the above, and has an object to provide a tire that can improve the visibility of a pattern portion. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, a tire according to one aspect of the present invention includes a pattern portion having a plurality of ridges arranged in parallel on the tire surface, the pattern portion having a plurality of wavy ridges that extend in a predetermined direction while oscillating in a wave-like manner, the plurality of wavy ridges being arranged side by side in the direction of the amplitude, and the plurality of wavy ridges being arranged such that the phases of the amplitudes of adjacent wavy ridges are shifted from each other. [Effects of the Invention]

[0007] The tire according to the present invention has an effect of improving the visibility of the pattern portion. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a pneumatic tire according to an embodiment taken along the tire meridian direction. [Figure 2] FIG. 2 is a plan view showing a tire side portion of the tire shown in FIG. [Figure 3] FIG. 3 is an enlarged view of a part of the marking portion on the tire side shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view of a portion of the marking portion shown in FIG. [Figure 5] FIG. 5 is an enlarged view of a part of the marking portion on the tire side portion shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view of a portion of the marking portion shown in FIG. [Figure 7] FIG. 7 is an enlarged view of a part of the marking portion on the tire side portion shown in FIG. [Figure 8] FIG. 8 is a cross-sectional view of a portion of the marking portion shown in FIG. [Figure 9] FIG. 9 is an enlarged view of the pattern portion. [Figure 10] FIG. 10 is a partially enlarged cross-sectional view of the pattern portion. [Figure 11] FIG. 11 is an explanatory diagram showing a modified example of the pneumatic tire according to the embodiment, in which both ends of the secondary ridge are connected to the wavy ridge. [Figure 12]FIG. 12 is an explanatory diagram showing a modified example of the pneumatic tire according to the embodiment, in which both ends of the secondary ridge are spaced apart from the wavy ridge. [Figure 13] FIG. 13 is an explanatory diagram showing a modified example of the pneumatic tire according to the embodiment, in which the wavy ridges are arranged with a shift of less than half the wavelength. [Figure 14] FIG. 14 is an explanatory diagram showing a modified example of the pneumatic tire according to the embodiment, in which the wavy ridges are arranged with a shift of less than half the wavelength. [Figure 15] FIG. 15 is an explanatory diagram showing a modified example of the pneumatic tire according to the embodiment, in which the wavy ridges are arranged with a shift of less than half the wavelength. [Figure 16] FIG. 16 is a table showing the results of a performance evaluation test of a pneumatic tire. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail 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.

[0010] [Embodiment] Fig. 1 is a cross-sectional view in the tire meridian direction of a pneumatic tire according to an embodiment. Fig. 1 shows a cross-sectional view of one side region in the tire radial direction of a pneumatic tire 1 mounted on a rim 20. In the embodiment, a pneumatic tire, that is, a pneumatic radial tire for passenger cars, will be described as an example of a tire.

[0011] The tire meridian cross section shown in Figure 1 is defined as a cross section of the tire cut by a plane including the tire rotational 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 rotational axis. The tire width direction is defined as the direction parallel to the tire rotational axis, and the inner side in the tire width direction refers to the side toward the tire equatorial plane CL in the tire width direction, and the outer side in the tire width direction refers to the side away from the tire equatorial plane CL in the tire width direction. The tire radial direction is defined as the direction perpendicular to the tire rotational axis, and the inner side in the tire radial direction refers to the side toward the tire rotational axis in the tire radial direction, and the outer side in the tire radial direction refers to the side away from the tire rotational axis in the tire radial direction. The tire circumferential direction refers to the direction around the tire rotational axis as the central axis.

[0012] The pneumatic tire 1 has an annular structure centered on the tire rotation axis, and as shown in FIG. 1, includes a pair of bead cores 11, a pair of bead fillers 12, a carcass layer 13, a belt layer 14, a tread rubber 15, a pair of sidewall rubbers 16, and a pair of rim cushion rubbers 17.

[0013] The pair of bead cores 11 are formed by winding one or more bead wires made of steel in an annular and multiply fashion, and are embedded in the bead portions to form the cores of the bead portions on both sides in the tire width direction.

[0014] The pair of bead fillers 12 are respectively arranged on the outer periphery of the pair of bead cores 11 in the tire radial direction to reinforce the bead portion.

[0015] 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. The carcass layer 13 is toroidally laid between the bead cores 11 on both sides in the tire width direction to form the tire framework. Both ends of the carcass layer 13 are wrapped around and secured to the outside in the tire width direction so as to enclose 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. The carcass cords of the carcass layer 13 have a cord angle (defined as the inclination angle of the carcass cord in the longitudinal direction with respect to the tire circumferential direction) of 80 degrees or more and 100 degrees or less in absolute value.

[0016] The belt layer 14 is formed by laminating, for example, 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 include, from the inner side in the tire radial direction, a pair of cross belts 141, 142 and a belt cover 143.

[0017] 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. The cross belts 141, 142 have belt cords with an absolute 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. The cross belts 141, 142 have belt cords with cord angles of opposite signs, and are layered with the longitudinal directions of the belt cords crossing each other (so-called cross-ply structure). The cross belts 141, 142 are layered and arranged on the outer side of the carcass layer 13 in the tire radial direction.

[0018] The belt cover 143 is formed by covering a belt cover cord made of steel or organic fiber material with coating rubber. In the belt cover 143, the belt cover cord has a cord angle (defined as the inclination angle of the belt cord in the longitudinal direction with respect to the tire circumferential direction) 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 spirally winding this strip material multiple times around the outer circumferential surfaces of the cross belts 141, 142 in the tire circumferential direction. The belt cover 143 is arranged to cover the entire area of ​​the cross belts 141, 142.

[0019] The tread rubber 15 is disposed on the outer periphery of the carcass layer 13 and the belt layer 14 in the tire radial direction to form the tread portion of the tire 1. The tread rubber 15 is made of a rubber material that has excellent ground contact characteristics and weather resistance, and is exposed over the entire outer periphery of the tire to form the tread surface.

[0020] The pair of sidewall rubbers 16 are disposed on the outer sides of the carcass layer 13 in the tire width direction, and form sidewall portions on both sides in the tire width direction.

[0021] The pair of rim cushion rubbers 17 extend from the inner side in the tire radial direction to the outer side in the tire width direction of each bead core 11 and each turned-up portion of the carcass layer 13, and form the rim fitting surface of the bead portion.

[0022] FIG. 2 is a plan view showing a tire side portion of the tire shown in FIG.

[0023] As shown in FIG. 2, the pneumatic tire 1 of the embodiment includes a marking portion 2 and a peripheral region 3 in a tire side portion 18.

[0024] The tire side portion 18 is a surface that continues uniformly from the ground contact edge T of the tread surface outward in the tire width direction and from the rim check line R outward in the tire radial direction, and is an annular surface that extends along the tire circumferential direction. The ground contact edges T refer to both outermost ends in the tire width direction in the region where the tread surface of the pneumatic tire 1 comes into contact with the road surface when the pneumatic tire 1 is mounted on a normal rim, inflated to the normal internal pressure, and subjected to 70% of the normal load, and continue in the tire circumferential direction. The rim check line R is a line used to check whether the tire is mounted properly on the rim, and is generally shown as a circular convex line that continues in the tire circumferential direction along the front side of the bead portion 10, radially outward of the rim flange 20a and near the rim flange 20a.

[0025] Here, the normal rim refers to the "applicable rim" defined by JATMA, the "design rim" defined by TRA, or the "measuring rim" defined by ETRTO. The normal internal pressure refers to the "maximum air pressure" defined by JATMA, the maximum value of the "tire load limits at various cold inflation pressures" defined by TRA, or the "inflation pressures" defined by ETRTO. The normal load refers to the "maximum load capacity" defined by JATMA, the maximum value of the "tire load limits at various cold inflation pressures" defined by TRA, or the "load capacity" defined by ETRTO. In the case of the pneumatic tire 1 of the embodiment, the normal load is 88% of the maximum load capacity at the normal internal pressure.

[0026] The mark 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. Multiple mark portions 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 element 2A of the letters "YOKOHAMA" indicating the tire manufacturer and element 2B of a logo with a stylized "Y," the initial letter of the name, is applied to the surface of the tire side portion 18. A pair of mark portions 2 are arranged in opposing positions in the tire circumferential direction on the annular tire side portion 18.

[0027] The marking portion 2 has a radial height Ha [mm] of each element 2A relative to the tire cross-sectional height SH [mm] (see FIG. 1) in the range of 0.05≦Ha / SH≦0.80, and preferably in the range of 0.10≦Ha / SH≦0.70. This improves the visibility of the marking portion 2. The radial height Ha of the element 2A is measured as the maximum extension dimension of the element 2A in the tire radial direction.

[0028] The tire cross-sectional height SH is half the distance between the tire outer diameter and the rim diameter, and is measured with the pneumatic tire 1 mounted on a specified rim, a specified internal pressure applied, and no load applied.

[0029] The peripheral region 3 is a region surrounding the marking portion 2 and is formed on the surface of the tire side portion 18. The peripheral region 3 may be a smooth surface having a smooth surface, or may be an uneven surface that has been subjected to surface processing. In the embodiment, the peripheral region 3 is formed between a pair of narrow ribs 41, 42 that each extend in the tire circumferential direction and are positioned at different positions in the tire radial direction. This enhances the design of the tire side portion 18 of the pneumatic tire 1. Furthermore, the peripheral region 3 has an annular structure that extends around the entire circumference of the tire side portion 18 in the tire circumferential direction, and thus includes both of the pair of marking portions 2.

[0030] In the pneumatic tire 1 of the embodiment, the marking portion 2 and the peripheral region 3 are disposed radially outward of the tire maximum width position Ac. More specifically, the marking portion 2 and the peripheral region 3 are disposed in an area (see FIG. 1 ) from the tire ground contact edge T to the tire maximum width position Ac, with a pair of narrow ribs 41, 42 extending in the tire circumferential direction to define the peripheral region 3, and the marking portion 2 is disposed between these narrow ribs 41, 42. This increases the visibility of the marking portion 2 in the pneumatic tire 1. The pneumatic tire 1 is not limited to this configuration, and although not explicitly shown in the drawings, the marking portion 2 and the peripheral region 3 may be disposed within the tire side portion 18, including the tire maximum width position Ac, or may be disposed radially inward of the tire maximum width position Ac.

[0031] The tire maximum width position Ac is defined as the maximum width position of the tire section width within the tire side portion 18. The tire section width is measured as the linear distance in the tire width direction between the sidewalls, excluding irregularities such as the marking portion 2, the peripheral region 3, and patterns and letters such as the narrow ribs 41, 42 on the surface of the tire side portion 18, when the tire is mounted on a specified rim, pressurized to a specified internal pressure, and in an unloaded state.

[0032] The fine ribs 41, 42 have a width of 0.4 mm to 0.8 mm and a height from the surface of the tire side portion 18 of 0.1 mm to 1.0 mm, and function as a discharge path for residual air during tire vulcanization. This reduces the occurrence of vulcanization defects in the marking portion 2 and the surrounding area 3 of the pneumatic tire 1. In addition, in the pneumatic tire 1 of the embodiment, the fine rib 41 on the outer side in the tire radial direction is located at a mold split position of the tire molding die.

[0033] Furthermore, the marking portion 2 has a radial height Ha [mm] of the element 2A, relative to the spacing Hb [mm] of the fine ribs 41, 42 in the tire radial direction, in the range of 0.30≦Ha / Hb≦0.80, and preferably in the range of 0.40≦Ha / Hb≦0.70. Furthermore, in the pneumatic tire 1 of the embodiment, it is preferable that the marking portion 2 is disposed away from the pair of fine ribs 41, 42, as shown in Fig. 2. As a result, the visibility of the marking portion 2 in the pneumatic tire 1 is improved.

[0034] 3, 5, and 7 are enlarged views of a portion of the marking portion of the tire side portion shown in FIG. 2. FIG. 4 is a cross-sectional view (cross-sectional view taken along line AA in FIG. 3) of a portion of the marking portion shown in FIG. 3. FIG. 6 is a cross-sectional view (cross-sectional view taken along line BB in FIG. 5) of a portion of the marking portion shown in FIG. 7. FIG. 8 is a cross-sectional view (cross-sectional view taken along line CC in FIG. 7) of a portion of the marking portion shown in FIG. 3 to 8. For convenience, the ridges 7 arranged in the pattern portion 4 are simplified by hatching.

[0035] In the pneumatic tire 1 shown in Figures 3 and 4, the marking portion 2 (element 2A) is formed as a recessed portion 5 that is recessed into the peripheral region 3 in the tire side portion 18. That is, the marking portion 2 (element 2A) is formed such that the inner wall surface of the recessed portion 5 forms the contour line. In this pneumatic tire 1, the surface that forms the peripheral region 3 is a smooth surface, and a pattern portion 4, which will be described below, is provided on the smooth tire surface 5A that is the inner bottom of the recessed portion 5 of the marking portion 2 (element 2A).

[0036] In the pneumatic tire 1 shown in FIGS. 5 and 6, in the tire side portion 18, the marking portion 2 (element 2A) is formed as a convex portion 6 that protrudes from the surface with respect to the peripheral region 3. That is, the marking portion 2 (element 2A) is formed with the outer wall surface of the convex portion 6 as a contour line. In this pneumatic tire 1, the surface forming the protruding end of the convex portion 6 is a smooth surface, and a pattern portion 4, which will be described below, is provided around the convex portion 6 of the marking portion 2 (element 2A) on the tire surface 3A of the smooth peripheral region 3 (tire side portion 18).

[0037] In the pneumatic tire 1 shown in FIGS. 7 and 8, in the tire side portion 18, the marking portion 2 (element 2A) is formed as a convex portion 6 that protrudes from the surface with respect to the peripheral region 3. That is, the marking portion 2 (element 2A) is formed with the outer wall surface of the convex portion 6 as a contour line. In this pneumatic tire 1, the surface forming the protruding end of the convex portion 6 is a smooth surface, and a pattern portion 4, which will be described below, is provided on the tire surface 3A of the smooth peripheral region 3 (tire side portion 18) around the outer wall surface of the convex portion 6 of the marking portion 2 (element 2A).

[0038] Fig. 9 is an enlarged view of the pattern portion, and Fig. 10 is an enlarged partial cross-sectional view of the pattern portion (cross-sectional view taken along line DD in Fig. 9).

[0039] When the pattern portion 4 is formed on the tire surface 5A, which is the bottom surface of the recessed portion 5 that forms the outline of the marking portion 2 (element 2A) as shown in Figures 3 and 4, the pattern portion 4 is arranged at a position recessed from the peripheral region 3 as shown in Figure 10. When the pattern portion 4 is formed on the tire surface 3A in the peripheral region 3 that is around the protruding portion 6 that forms the outline of the marking portion 2 (element 2A) as shown in Figures 5 to 8, the pattern portion 4 is arranged at a position recessed from the protruding portion 6 as shown in Figure 10.

[0040] 9, a plurality of ridges 7 are arranged in parallel. The pattern portion 4 (4A) has a plurality of wavy ridges 7A and a plurality of sub-ridges 7B, which are ridges 7.

[0041] The wavy ridges 7A are ridges 7 that extend in a predetermined direction while oscillating in a wavy manner. The multiple wavy ridges 7A are arranged side by side in the direction of the oscillation of the oscillating wavy ridges 7A.

[0042] 10, the wavy ridges 7A and secondary ridges 7B are rib-like protrusions that protrude from the tire surfaces 3A and 5A and are formed with triangular cross-sectional shapes that narrow from bases 7Ab and 7Bb on the tire surfaces 3A and 5A toward apexes 7Aa and 7Ba. It is preferable that the apexes 7Aa and 7Ba of the ridges 7A and 7B are pointed.

[0043] As shown in Figures 9 and 10, the width W of the largest bases 7Ab and 7Bb of the wavy ridges 7A and secondary ridges 7B is preferably in the range of 0.03 mm to 0.3 mm. The width W of the wavy ridges 7A and secondary ridges 7B is measured as the width in a cross section perpendicular to the extension direction of the wavy ridges 7A and secondary ridges 7B, respectively. Furthermore, as shown in Figures 9 and 10, the pitch P between adjacent peaks 7Aa and 7Ba of the wavy ridges 7A and secondary ridges 7B is preferably 0.5 mm or less, and more preferably 0.25 mm or less. In this way, the pattern portion 4, in which the width W and pitch P of the wavy ridges 7A and secondary ridges 7B are defined, can improve the processability of the pneumatic tire 1 without hindering its removal from the tire mold.

[0044] As described above, when the wavy ridges 7A and secondary ridges 7B that make up the pattern portion 4 are formed on the tire surface 5A, which is the bottom surface of the recessed portions 5 that make up the outline of the marking portion 2 (element 2A), they are arranged in positions recessed from the peripheral region 3 as shown in Fig. 10. Furthermore, when the wavy ridges 7A and secondary ridges 7B that make up the pattern portion 4 are formed on the tire surface 3A in the peripheral region 3 that is around the protruding portions 6 that make up the outline of the marking portion 2 (element 2A), they are arranged in positions recessed from the protruding portions 6 as shown in Fig. 10. In this configuration, as shown in Fig. 10, the height T of the wavy ridges 7A and secondary ridges 7B from the tire surfaces 5A and 3A to their peaks 7Aa and 7Ba is preferably in the range of 0.1 mm to 1.5 mm, and more preferably in the range of 0.2 mm to 1.3 mm.

[0045] Thus, the pattern portion 4 in which the wavy ridges 7A and the secondary ridges 7B have a height T can improve the processability of the pneumatic tire 1 without hindering removal from the tire mold. Furthermore, as shown in Fig. 10 , the height T of the wavy ridges 7A and the secondary ridges 7B from the tire surfaces 5A and 3A to the peaks 7Aa and 7Ba, relative to the height T0 of the recesses 5 and the height T0 of the protrusions 6, is preferably in the range of 0.5≦T / T0<1.0, and more preferably in the range of 0.7≦T / T0≦0.95. The pattern portion 4 configured in this manner can prevent foreign matter from coming into contact with the wavy ridges 7A and the secondary ridges 7B due to the height T0 of the recesses 5 and the height T0 of the protrusions 6, thereby preventing damage to the wavy ridges 7A and the secondary ridges 7B.

[0046] In the pattern portion 4A(4) shown in FIG. 9, the wavy ridges 7A extend in a predetermined direction while oscillating in a wavy manner. In this embodiment, the wavy ridges 7A are formed in a wavy shape that oscillates in a so-called sinusoidal wave shape. The pattern portion 4A(4) has a plurality of wavy ridges 7A, and the plurality of wavy ridges 7A are arranged so that they extend in the same direction. As such, the plurality of wavy ridges 7A in the pattern portion 4A(4) are arranged side by side in the direction of amplitude of the wavy ridges 7A. In other words, when the direction in which the wavy ridges 7A extend is defined as a first direction, the plurality of wavy ridges 7A are arranged at intervals in a second direction that is perpendicular to the first direction in a plan view of the pattern portion 4A(4).

[0047] As described above, the multiple wavy ridges 7A included in the pattern portion 4A(4) are arranged such that the phases of the amplitudes of adjacent wavy ridges 7A are shifted from each other in the extension direction of the wavy ridges 7A. In the embodiment, the wavy ridges 7A are arranged such that the phases of adjacent wavy ridges 7A are shifted from each other by half the wavelength of the sine wave that is the amplitude shape of the wavy ridges 7A.

[0048] For this reason, in adjacent wavy ridges 7A in the second direction, among the amplitude protrusions and recesses that move away from and toward the other wavy ridge 7A, the amplitude convex portions that move toward the side where the other wavy ridge 7A is located face each other. Similarly, in adjacent wavy ridges 7A in the second direction, among the amplitude protrusions and recesses that move away from and toward the other wavy ridge 7A, the amplitude concave portions 7Ac that move away from the side where the other wavy ridge 7A is located face each other. That is, in adjacent wavy ridges 7A, the amplitude convex portions that move toward the other wavy ridge 7A are located at the same position in the first direction, and the amplitude concave portions 7Ac that move away from the other wavy ridge 7A are located at the same position in the first direction.

[0049] The pattern portion 4A(4) in which a plurality of wavy ridges 7A are arranged in this manner has secondary ridges 7B in the portions between the amplitude recesses 7Ac of adjacent wavy ridges 7A. That is, in the pattern portion 4A(4), the secondary ridges 7B are arranged in the portions where the amplitude recesses 7Ac of adjacent wavy ridges 7A face each other, thereby increasing the distance between the wavy ridges 7A. The secondary ridges 7B are curved in a direction convex in the opposite direction to the direction in which the amplitude recesses 7Ac of one wavy ridge 7A are located, among the amplitude recesses 7Ac of adjacent wavy ridges 7A, that is, they are curved in a direction along the recesses 7Ac of the other wavy ridge 7A.

[0050] A secondary ridge 7B disposed between adjacent wavy ridges 7A is connected to one of the adjacent wavy ridges 7A. The secondary ridge 7B is connected to the adjacent wavy ridge 7A on the side where the direction of curvature of the recesses 7Ac in the wavy ridge 7A and the direction of curvature of the secondary ridge 7B are opposite to each other. The magnitude of curvature of the secondary ridge 7B in the second direction relative to the length in the first direction is approximately the same as the magnitude of curvature of the recesses 7Ac in the wavy ridge 7A to which the secondary ridge 7B is connected.

[0051] The degree of curvature of the secondary ridges 7B may be different from the degree of curvature of the recesses 7Ac in the wavy ridges 7A. The secondary ridges 7B may also be formed straight without being curved.

[0052] The secondary ridge 7B connected to the wavy ridge 7A has one end 7Bc in the extension direction of the secondary ridge 7B connected to the wavy ridge 7A and the other end 7Bd spaced apart from the wavy ridge 7A. One end 7Bc of the secondary ridge 7B is connected to the wavy ridge 7A near an inflection point of the amplitude in the wavy ridge 7A, and the secondary ridge 7B extends smoothly from the wavy ridge 7A. The other end 7Bd of the secondary ridge 7B in the extension direction is located near an inflection point adjacent in the first direction to the inflection point of the amplitude in the wavy ridge 7A to which the secondary ridge 7B is connected, and is spaced apart from the wavy ridge 7A.

[0053] In the pattern portion 4A(4) thus formed, the wavelength H1 of the wavy ridges 7A oscillating in a sinusoidal wave shape is preferably within the range of 0.5 mm to 1.5 mm. Furthermore, in the pattern portion 4A(4), when adjacent wavy ridges 7A in the second direction are defined as a pair of wavy ridges 7A, the distance H2 or pitch H2 between the pair of wavy ridges 7A in the second direction is preferably within the range of 0.5 mm to 1.0 mm.

[0054] This pneumatic tire 1 is manufactured using a tire molding die capable of transferring the above-described pattern portion 4 (4A) onto the surface of the tire side portion 18.

[0055] Specifically, the pneumatic tire 1 is manufactured, for example, by the following manufacturing process. First, tire components such as the bead wires that form the bead core 11, the carcass plies that form the carcass layer 13, the belt plies 141 to 143 that form the belt layer 14, the tread rubber 15, the sidewall rubber 16, and the rim cushion rubber 17 are placed in a molding machine to form a green tire (not shown). Next, the green tire of the pneumatic tire 1 is filled into a tire vulcanization mold (not shown) that includes a tire molding die. Next, the green tire of the pneumatic tire 1 is expanded radially outward by a pressure device and abuts against the tire molding die. Next, the tire vulcanization mold is heated, and rubber molecules of the green tire are bonded with sulfur molecules, thereby progressing vulcanization of the pneumatic tire 1. At this time, the shape of the molding surface of the tire molding die is transferred to the outer peripheral surface of the green tire, and the surface of the tire side portion 18 of the pneumatic tire 1 is formed. The tire after vulcanization is then removed from the tire vulcanization mold.

[0056] Furthermore, the pattern portions 4 (4A) on the tire surfaces 3A, 5A are formed by irregularities formed on the molding surface of the tire mold. The irregularities on the molding surface of the tire mold are formed, for example, by laser processing. That is, in the tire mold, the irregularities on the molding surface are formed by laser processing, with wavy grooves corresponding to the wavy ridges 7A and minor grooves corresponding to the minor ridges 7B. A tire mold in which each groove is formed by laser processing can mold the wavy ridges 7A and minor ridges 7B having the shapes described above. Furthermore, a tire mold in which each groove is formed by laser processing has surface roughness on the processed surface compared to a machined tire mold, and therefore has good mold release properties even for the wavy ridges 7A and minor ridges 7B having the shapes described above, contributing to improved productivity of the pneumatic tire 1.

[0057] The pneumatic tire 1 of the embodiment has a plurality of wavy ridges 7A that oscillate in the shape described above, and the plurality of wavy ridges 7A are arranged such that the amplitude phases of adjacent wavy ridges 7A are shifted from each other. Therefore, in this pneumatic tire 1, the distance between adjacent wavy ridges 7A varies depending on the position in the extension direction of the wavy ridges 7A, allowing the pattern portion 4A(4) to have a varying density of ridges 7. This causes the pattern portion 4A(4) to have a different contrast (i.e., a difference in light and dark) depending on the position in the extension direction of the wavy ridges 7A, i.e., the position in the first direction, changing its appearance. This can enhance the impression made when the pattern portion 4A(4) is visually recognized. As a result, the visibility of the pattern portion 4A(4) can be improved.

[0058] Furthermore, because the wavy ridges 7A oscillate in a sinusoidal wave shape, the contrast changes regularly as the distance between adjacent wavy ridges 7A changes depending on the position in the extension direction of the wavy ridges 7A. This enhances the impression that the pattern portion 4A(4) leaves when viewed. As a result, the visibility of the pattern portion 4A(4) can be improved.

[0059] Furthermore, since the wavy ridges 7A are arranged with a phase shift of 1 / 2 the wavelength of the sine wave between adjacent wavy ridges 7A, the distance between adjacent wavy ridges 7A can be more reliably changed depending on the position in the extension direction of the wavy ridges 7A. This makes it possible to more reliably change the contrast depending on the position in the extension direction of the wavy ridges 7A, thereby enhancing the degree of impression when the pattern portion 4A(4) is visually recognized. As a result, the visibility of the pattern portion 4A(4) can be improved.

[0060] Furthermore, the pattern portion 4A(4) has a sub-ridge 7B between the amplitude recesses 7Ac of adjacent wavy ridges 7A, which prevents the distance between adjacent wavy ridges 7A from becoming too large. This prevents the contrast in the pattern portion 4A(4) from changing too much, and reduces the sense of incongruity felt when viewing the pattern portion 4A(4). As a result, the visibility of the pattern portion 4A(4) can be improved.

[0061] Furthermore, the secondary ridge 7B is curved so that it is convex in the opposite direction to the direction in which the amplitude recesses 7Ac of one of the adjacent wavy ridges 7A are located. Therefore, when the amplitude phases of the adjacent wavy ridges 7A are shifted from each other, the secondary ridge 7B can more reliably prevent excessive contrast changes caused by the distance between the wavy ridges 7A becoming too large at the positions of the recesses 7Ac of the wavy ridges 7A. This can reduce the sense of incongruity felt when viewing the pattern portion 4A(4) due to excessive contrast changes in the pattern portion 4A(4). As a result, the visibility of the pattern portion 4A(4) can be improved.

[0062] Furthermore, because the secondary ridges 7B are connected to one of the adjacent wavy ridges 7A, the secondary ridges 7B can be arranged with continuity relative to the wavy ridges 7A. This allows the rubber to flow more easily to the positions of the secondary ridges 7B during vulcanization molding of the pneumatic tire 1, and prevents molding defects caused by the rubber not flowing to the positions of the secondary ridges 7B. As a result, molding defects of the pattern portion 4A(4) can be prevented, and molding of the pattern portion 4A(4) can be more reliably performed.

[0063] Furthermore, since one end 7Bc of the secondary ridge 7B in the extension direction is connected to the wavy ridge 7A and the other end 7Bd is spaced apart from the wavy ridge 7A, the variation in density of the ridges 7 in the pattern portion 4A(4) can be made larger. This allows the contrast variation in the pattern portion 4A(4) to be made larger with more certainty, enhancing the degree of impression when the pattern portion 4A(4) is visually recognized. As a result, the visibility of the pattern portion 4A(4) can be improved.

[0064] Furthermore, in the pattern portion 4A(4), the width W of the ridges 7 is within a range of 0.03 mm to 0.3 mm, and the pitch P between adjacent ridges 7 is 0.5 mm or less. Therefore, as shown in FIG. 10 , in the pattern portion 4A(4), light L incident between adjacent ridges 7 is reflected multiple times from the peaks 7Aa, 7Ba toward the bases 7Ab, 7Bb toward the tire surface 5A, 3A, where it is absorbed, causing the pattern portion 4A(4) to appear black. This clarifies the contrast between the pattern portion 4A(4) and other areas where the pattern portion 4A(4) is not present. As a result, the visibility of the pattern portion 4A(4) is improved, and the visibility of the marking portion 2 on the tire sidewall 18 is also improved.

[0065] Furthermore, the wavy ridges 7A and sub-ridges 7B of the pattern portion 4A(4) are each curved, so that the light L that enters the pattern portion 4A(4) can be dispersed and reflected by the ridges 7. This makes the pattern portion 4 appear blacker, and clarifies the contrast between the pattern portion 4A(4) and other areas without the pattern portion 4A(4). As a result, the visibility of the pattern portion 4A(4) can be improved, and the visibility of the marking portion 2 applied to the tire side portion 18 can also be improved.

[0066] Furthermore, when the pattern portion 4A(4) is provided on the inner bottom of the recessed portion 5 of the marking portion 2 recessed from the tire surface 5A, the pattern portion 4A(4) can make the marking portion 2 recessed from the tire surface 5A stand out. As a result, the visibility of the marking portion 2 provided on the tire side portion 18 can be improved.

[0067] Furthermore, when the pattern portion 4A(4) is provided around the convex portion of the marking portion 2 that protrudes from the tire surface 3A, the marking portion 2 that protrudes from the tire surface 3A can be made to stand out by the highly visible pattern portion 4A(4) that is arranged around the marking portion 2. As a result, the visibility of the marking portion 2 provided on the tire side portion 18 can be improved.

[0068] Furthermore, when the pattern portion 4A(4) is provided to outline the protrusions of the marking portion 2 protruding from the tire surface 3A, the marking portion 2 protruding from the tire surface 3A can be made to stand out by being outlined with the highly visible pattern portion 4A(4). As a result, the visibility of the marking portion 2 provided on the tire side portion 18 can be improved.

[0069] [Variations] In the above-described embodiment, one end 7Bc of the secondary ridge 7B is connected to the wavy ridge 7A and the other end 7Bd is spaced apart from the wavy ridge 7A, but the secondary ridge 7B may be formed in any other form.

[0070] FIG. 11 is an explanatory diagram illustrating a modified example of the pneumatic tire 1 according to the embodiment, in which both ends of the secondary ridge 7B are connected to the wavy ridge 7A. The secondary ridge 7B may have both ends 7Bc and 7Bd in the extension direction of the secondary ridge 7B connected to the wavy ridge 7A, as in the pattern portion 4B(4) shown in FIG. 11 . Connecting both ends 7Bc and 7Bd of the secondary ridge 7B to the wavy ridge 7A ensures that rubber flows more easily to the position of the secondary ridge 7B during vulcanization molding of the pneumatic tire 1. This prevents molding defects caused by rubber not flowing to the position of the secondary ridge 7B. Furthermore, connecting both ends 7Bc and 7Bd of the secondary ridge 7B to the wavy ridge 7A ensures the strength of the secondary ridge 7B, thereby preventing damage to the secondary ridge 7B when a foreign object comes into contact with the secondary ridge 7B. As a result, defective molding of the pattern portion 4B(4) can be suppressed, the molding of the pattern portion 4B(4) can be performed more reliably, and damage to the pattern portion 4B(4) can be suppressed.

[0071] FIG. 12 is an explanatory diagram illustrating a modified example of the pneumatic tire 1 according to the embodiment, in which both ends of the secondary ridge 7B are spaced apart from the wavy ridge 7A. The secondary ridge 7B may have both ends 7Bc and 7Bd spaced apart from the wavy ridge 7A in the extension direction of the secondary ridge 7B, as in the pattern portion 4C(4) shown in FIG. 12 . By spaced apart both ends 7Bc and 7Bd from the wavy ridge 7A, the secondary ridge 7B can be provided independently of the wavy ridge 7A. This reduces the influence of the wavy ridge 7A on the secondary ridge 7B, making it easy to provide the secondary ridge 7B. This makes it easy to provide the secondary ridge 7B, which prevents the distance between adjacent wavy ridges 7A from becoming too large, and prevents excessive changes in contrast in the pattern portion 4C(4). As a result, it is easy to reduce the sense of incongruity felt when viewing the pattern portion 4C(4), improving the visibility of the pattern portion 4C(4).

[0072] Furthermore, in the above-described embodiment, the wavy ridges 7A are arranged so that adjacent wavy ridges 7A are shifted in phase from each other by a length of 1 / 2 the wavelength of the sine wave, but adjacent wavy ridges 7A may also be shifted by other amounts.

[0073] 13 to 15 are explanatory diagrams showing modified examples of the pneumatic tire 1 according to the embodiment, in which the wavy ridges 7A are arranged with a shift in phase by less than half the wavelength. As shown in FIGS. 13 to 15, the wavy ridges 7A may be arranged so that adjacent wavy ridges 7A are shifted in phase by less than half the wavelength of the sine wave. For example, as in pattern portion 4D(4) shown in FIG. 13, the wavy ridges 7A may be arranged so that adjacent wavy ridges 7A are shifted in phase by less than half the wavelength of the sine wave, and the secondary ridges 7B may have one end 7Bc connected to the wavy ridge 7A and the other end 7Bd spaced apart from the wavy ridge 7A.

[0074] Alternatively, as in pattern portion 4E(4) shown in Fig. 14, adjacent wavy ridges 7A may be arranged with a phase shift of less than half the wavelength of the sine wave, and both ends 7Bc and 7Bd of the minor ridges 7B in the extension direction may be connected to the wavy ridge 7A. Alternatively, as in pattern portion 4F(4) shown in Fig. 15, adjacent wavy ridges 7A may be arranged with a phase shift of less than half the wavelength of the sine wave, and both ends 7Bc and 7Bd of the minor ridges 7B in the extension direction may be spaced apart from the wavy ridge 7A.

[0075] In the present embodiment, as described above, a pneumatic tire 1 has been described as an example of a tire. The pneumatic tire 1 can be filled with air, an inert gas such as nitrogen, or other gases. However, the configuration of the pattern portion of the pneumatic tire 1 described in the present embodiment 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.

[0076] [Example] 16 is a table showing the results of a performance evaluation test of the pneumatic tire 1. Hereinafter, a performance evaluation test will be described for the above-mentioned pneumatic tire 1, a conventional pneumatic tire 1, and the pneumatic tire 1 according to the present invention. The performance evaluation test was a test on the visibility of the pattern portion.

[0077] In the visibility evaluation test, a test tire with a tire size of 255 / 35R19 (96Y) is mounted on a rim with a rim size of 19x9J, and the test tire is pressurized according to the JATMA standard. An inspector then visually inspects the tire side of the test tire from a distance of 5 m to perform a sensory evaluation of the visibility of the pattern, which is an index of the conspicuousness of the pattern. This evaluation is performed using an index evaluation with the comparative example as the standard (100), and the higher the value, the better.

[0078] The performance evaluation test was conducted on 12 types of pneumatic tires, including a conventional pneumatic tire and Examples 1 to 11, which are pneumatic tires 1 according to the present invention. Of these, the conventional pneumatic tire has wavy ridges in the pattern portion, but the amplitude phases of adjacent wavy ridges are not shifted from each other.

[0079] In contrast, in Examples 1 to 11, which are examples of the pneumatic tire 1 according to the present invention, the wave-like ridges 7A of the pattern portion 4 are all shifted in amplitude phase between adjacent wave-like ridges 7A. Furthermore, the pneumatic tires 1 of Examples 1 to 11 differ from one another in whether the shift between adjacent wave-like ridges 7A is half the wavelength, the presence or absence of secondary ridges 7B, the shape of the secondary ridges 7B, the form of connection of the secondary ridges 7B to the wave-like ridges 7A, the width of the ridges 7, and the pitch of the ridges 7.

[0080] As a result of conducting a performance evaluation test using these pneumatic tires 1, it was found that the pneumatic tires 1 according to Examples 1 to 11 had pattern portions that were more noticeable than those of the conventional tire, and the visibility of the pattern portions was improved, as shown in Fig. 16. In other words, the pneumatic tires 1 according to Examples 1 to 11 can improve the visibility of the pattern portions.

[0081] The present disclosure encompasses the following inventions. Invention[1] The tire surface is equipped with a pattern of multiple parallel ridges, the pattern portion has a plurality of wave-like ridges that extend in a predetermined direction while oscillating in a wave-like manner, and the plurality of wave-like ridges are arranged side by side in the direction of the amplitude, The tire is characterized in that the plurality of wave-like ridges are arranged such that the amplitudes of adjacent wave-like ridges are out of phase with each other. Invention[2] The tire according to the invention [1], wherein the wavy ridges oscillate in a sinusoidal wave shape. Invention[3] The tire according to the invention [2], wherein the wavy ridges are arranged so that adjacent wavy ridges are shifted in phase from each other by a length of 1 / 2 the wavelength of the sine wave. Invention[4] The tire according to the invention [1] or [2], wherein the pattern portion has a secondary ridge in a portion between recesses of the amplitude in the adjacent wave-like ridges. Invention[5] The tire according to invention [4], wherein the secondary ridge is formed by curving in a direction convex in the opposite direction to the direction in which the recess of one of the wavy ridges of the amplitude of the adjacent wavy ridge is located. Invention[6] The tire according to the invention [4] or [5], wherein the secondary ridge is connected to one of the adjacent wavy ridges. Invention[7] The tire according to the invention [6], wherein one end of the secondary ridge in the extension direction of the secondary ridge is connected to the wavy ridge and the other end is spaced apart from the wavy ridge. Invention[8] The tire according to the invention [6], wherein the secondary ridge has both end portions in the extension direction of the secondary ridge connected to the wavy ridge. Invention[9] The pattern portion is A tire according to any one of inventions [1] to [8], wherein the width of the ridge is 0.03 mm or more and 0.3 mm or less, and the pitch between adjacent ridges is 0.5 mm or less. Invention

[10] The pattern portion is The tire according to any one of the inventions [1] to [9], wherein the marking is provided on the inner bottom of a recessed portion recessed from the tire surface. Invention

[11] The pattern portion is The tire according to any one of the inventions [1] to [9], wherein the marking is provided around the protrusion of the marking protruding from the tire surface. Invention

[12] The pattern portion is The tire according to any one of the inventions [1] to [9], wherein the marking portion is provided around the convex portion of the marking portion protruding from the tire surface. [Explanation of symbols]

[0082] 1 pneumatic tire 2. Emblem Section 2A,2B elements 3. Surrounding Areas 3A Tire Surface 4(4A, 4B, 4C, 4D, 4E, 4F) Pattern section 5 recess 5A Tire Surface 6 Convex part 7 Ridge 7A Wavy Ridge 7Aa,7Ba Top 7Ab,7Bb base 7Ac recess 7B Secondary Ridge 7Bc,7Bd End 10 Bead section 11 Bead core 12 Bead filler 13 Carcass layer 14 Belt Layer 15 Tread rubber 16 Sidewall rubber 17 Rim cushion rubber 18 Tire side 20 rims 20a rim flange 41,42 Thin rib

Claims

1. The tire surface is equipped with a pattern of multiple parallel ridges, the pattern portion has a plurality of wave-like ridges that extend in a predetermined direction while oscillating in a wave-like manner, and the plurality of wave-like ridges are arranged side by side in the direction of the amplitude, The tire is characterized in that the plurality of wave-like ridges are arranged such that the amplitudes of adjacent wave-like ridges are out of phase with each other.

2. 10. The tire of claim 1, wherein said undulating ridges oscillate in a sinusoidal manner.

3. The tire according to claim 2 , wherein the wavy ridges are arranged so that adjacent wavy ridges are shifted in phase from each other by a length of ½ of the wavelength of the sine wave.

4. The tire according to claim 1 or 2, wherein the pattern portion has a secondary ridge in a portion between recesses of the same amplitude in the adjacent wave-like ridges.

5. The tire according to claim 4 , wherein the secondary ridge is formed so as to be curved in a direction convex in the opposite direction to a direction in which the recess of one of the wavy ridges having the amplitude of the adjacent wavy ridges is located.

6. The tire of claim 5 , wherein the secondary ridge is connected to one of the adjacent wavy ridges.

7. The tire according to claim 6 , wherein one end of the secondary ridge in the extension direction of the secondary ridge is connected to the wavy ridge and the other end is spaced apart from the wavy ridge.

8. The tire according to claim 6 , wherein both end portions of the secondary ridge in the extension direction of the secondary ridge are connected to the wavy ridge.

9. The pattern portion is 2. The tire according to claim 1, wherein the width of the ridge is 0.03 mm or more and 0.3 mm or less, and the pitch between adjacent ridges is 0.5 mm or less.

10. The pattern portion is The tire according to claim 1 , wherein the marking is provided on an inner bottom of a recessed portion recessed from the tire surface.

11. The pattern portion is The tire according to claim 1 , wherein the marking is provided around a protruding portion of the marking protruding from the tire surface.

12. The pattern portion is The tire according to claim 1, wherein the marking is provided by edging a convex portion of the marking that protrudes from the tire surface.

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