Tire

Abstract

To provide a tire capable of suppressing poor appearance of a tire side part.SOLUTION: The tire 1 includes a pair of bead cores 11, 11, a carcass layer 13 stretched between the pair of bead cores 11, 11, and a tire side portion formed of a rubber member including a sidewall rubber 16. Additionally, the carcass layer 13 includes at least one carcass ply 131 that is turned up outward in the tire lateral direction so as to wrap around the pair of bead cores 11, 11 (see FIG. 2). The tire side portion includes a ridge region 4 in which a plurality of ridges 41 extending in the tire radial direction are arranged in the tire circumferential direction. Further, the ridge region 4 is arranged so as to cover the wind-up end portion 131e of at least one layer of the carcass ply 131 in the plan view of the tire side portion.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a tire, and more particularly to a tire that can suppress poor appearance of the tire side portion. [Background technology]

[0002] In recent years, tires have adopted a structure in which the rubber gauge of the tire side portion is thinned in order to reduce the tire weight. A technology described in Patent Document 1 is known as a conventional tire adopting such a structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 05-193311 Summary of the Invention [Problem to be solved by the invention]

[0004] However, a structure in which the rubber gauge of the tire side portion is thinned has the problem that irregularities in the structure inside the tire can cause poor appearance (so-called light failure) in the tire side portion.

[0005] Therefore, the present invention has been made in view of the above, and has an object to provide a tire that can suppress poor appearance of the tire side portions. [Means for solving the problem]

[0006] In order to achieve the above object, the tire of the present invention is a tire comprising a pair of bead cores, a carcass layer spanning the pair of bead cores, and a tire side portion made of a rubber member including sidewall rubber, wherein the carcass layer includes at least one carcass ply layer wound back outward in the tire width direction so as to encase the pair of bead cores, and the tire side portion comprises a ridge region formed by arranging a plurality of ridges extending in the tire radial direction in the tire circumferential direction, and the ridge region is arranged to cover the turned-up end portion of the at least one carcass ply layer in a plan view of the tire side portion. [Effects of the Invention]

[0007] A tire according to the present invention includes a pair of bead cores, a carcass layer spanning the pair of bead cores, and a tire side portion made of a rubber member including a sidewall rubber. The carcass layer includes at least one carcass ply wound back outward in the tire width direction to encase the pair of bead cores. The tire side portion includes a ridge region formed by arranging a plurality of ridges extending in the tire radial direction in the tire circumferential direction. The ridge region is arranged to cover a turned-up end portion e of at least one carcass ply in a plan view of the tire side portion. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view in the tire meridian direction showing a tire according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view showing a tire side portion of the tire shown in FIG. [Figure 3] FIG. 3 is an enlarged view showing the ridge region of the tire side portion shown in FIG. [Figure 4] FIG. 4 is a plan view showing the tire side portion shown in FIG. [Figure 5] FIG. 5 is a perspective view showing the ridge region shown in FIG. [Figure 6]FIG. 6 is a plan view showing a single ridge in the ridge region shown in FIG. [Figure 7] FIG. 7 is a side view showing a single ridge in the ridge region shown in FIG. [Figure 8] FIG. 8 is a front view showing a single ridge in the ridge region shown in FIG. [Figure 9] FIG. 9 is an explanatory diagram showing a modification of the ridge shown in FIG. [Figure 10] FIG. 10 is an explanatory diagram showing a modification of the ridge shown in FIG. [Figure 11] FIG. 11 is an explanatory diagram showing a modification of the ridge shown in FIG. [Figure 12] FIG. 12 is an explanatory diagram showing a modification of the ridge shown in FIG. [Figure 13] FIG. 13 is an explanatory diagram showing a modification of the ridge shown in FIG. [Figure 14] FIG. 14 is an explanatory diagram showing a modification of the ridge shown in FIG. [Figure 15] FIG. 15 is a table showing the results of performance tests on the tire according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] 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.

[0010] [tire] 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. In this embodiment, a pneumatic radial tire for passenger cars will be described as an example of a tire.

[0011] 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 the direction parallel to the tire rotation axis, and the tire radial direction is defined as the direction perpendicular to the tire rotation axis. Point T is the tire contact edge, and point A is the tire's maximum width position.

[0012] 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).

[0013] The pair of bead cores 11, 11 are formed by winding one or more steel bead wires in an annular and multiple pattern 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 periphery of the pair of bead cores 11, 11 in the tire radial direction, respectively, to reinforce the bead portions.

[0014] The carcass layer 13 has a single-layer structure consisting of one carcass ply or a multi-layer structure consisting of multiple carcass plies 131, 132 stacked together, and is toroidally laid between the left and right bead cores 11, 11 to form the tire framework. At least one carcass ply 131 is wrapped around and secured to the outside in the tire width direction so as to envelop the bead cores 11 and the bead fillers 12. The carcass plies 131, 132 are 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 have a cord angle (defined as the inclination angle of the carcass cords in the longitudinal direction with respect to the tire circumferential direction) of 80 degrees or more and 100 degrees or less.

[0015] 1, for example, the carcass layer 13 has a two-layer structure formed by laminating first and second carcass plies 131 and 132. The first carcass ply 131 is wound back and secured to the outside in the tire width direction so as to encase the bead core 11 and the bead filler 12. The second carcass ply 132 has a so-called turndown structure and is disposed on the outer periphery of the first carcass ply 131 so as to cover the turned-up end 131e of the first carcass ply 131, and is disposed outside the bead core 11 and the bead filler 12 in the tire width direction.

[0016] However, this is not limited to this, and multiple carcass plies may be wrapped around the bead core 11 and bead filler 12 and secured to the outside in the tire width direction, or the second carcass ply 132 having a turndown structure may be omitted (not shown).

[0017] The belt layer 14 is formed by laminating a plurality of belt plies 141 to 144, and is disposed by being wound around the outer periphery of the carcass layer 13. The belt plies 141 to 144 include a pair of cross belts 141, 142, a belt cover 143, and a pair of belt edge covers 144, 144.

[0018] 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 longitudinal directions of the belt cords crossing each other (so-called cross-ply structure). The pair of cross belts 141, 142 are layered and arranged on the outer side of the carcass layer 13 in the tire radial direction.

[0019] The belt cover 143 and the pair of belt edge covers 144, 144 are configured by covering belt cover cords made of steel or organic fiber material with coating rubber, and have a cord angle of 0 degrees or more and 10 degrees or less in absolute value. The belt cover 143 and the belt edge cover 144 are, for example, strip materials made by covering one or more belt cover cords with coating rubber, and are configured 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 disposed to cover the entire area of ​​the cross belts 141, 142, and the pair of belt edge covers 144, 144 are disposed to cover the left and right edge portions of the cross belts 141, 142 from the outside in the tire radial direction.

[0020] 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 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 inner side in the tire radial direction of the left and right bead cores 11, 11 and the turned-up portions of the carcass layer 13 to the outer side in the tire width direction to form the rim fitting surface of the bead portion.

[0021] The loss tangent tanδ of the sidewall rubber 16 at 60°C is in the range of 0.005 to 0.20, preferably 0.005 to 0.10. This suppresses deterioration of load durability due to the ridge region 4 of the tire side portion, which will be described later. The sidewall rubber 16 also has a rubber hardness Hs of 40 to 60, preferably 50 to 55. The sidewall rubber 16 also has a modulus M [MPa] at 100% elongation of 1.0 to 3.0, preferably 1.0 to 2.0.

[0022] The loss tangent tanδ is measured using a viscoelasticity spectrometer manufactured by Toyo Seiki Seisakusho Co., Ltd. under the conditions of a temperature of 60°C, a shear strain of 10%, an amplitude of ±0.5%, and a frequency of 20Hz.

[0023] Rubber hardness Hs is measured at a temperature of 20°C in accordance with JIS K6253.

[0024] The modulus (breaking strength) is measured by a tensile test using a dumbbell-shaped test piece at a temperature of 20°C in accordance with JIS K6251 (using a No. 3 dumbbell).

[0025] [Ridge area on tire side] FIG. 2 is an enlarged view showing a tire side portion of the tire 1 shown in FIG. 1. The figure shows one side region of the tire 1 bounded by the tire equatorial plane CL. FIG. 3 is an enlarged view showing the ridge region 4 of the tire side portion shown in FIG. 2. FIG. 4 is a plan view showing the tire side portion shown in FIG. 2. FIG. 5 is a perspective view showing the ridge region 4 shown in FIG. 2. FIGS. 6 to 8 are a plan view (FIG. 6), a side view (FIG. 7), and a front view (FIG. 8) showing a single ridge 41 of the ridge region 4 shown in FIG. 5.

[0026] In this tire 1, as shown in Fig. 2 and Fig. 3, the tire side portion includes a ridge region 4. As shown in Fig. 5, the ridge region 4 is made up of a plurality of ridges 41, and is defined as a region surrounded by imaginary lines (not shown) connecting the longitudinal ends of adjacent ridges 41. The ridges 41 are rib-like convex portions that protrude outward from the tire and extend in the tire radial direction. The plurality of ridges 41 are also arranged at a predetermined pitch length in the tire circumferential direction.

[0027] As shown in FIGS. 2 and 4, the ridge region 4 is disposed to cover a turned-up end portion 131e of at least one carcass ply 131 in a plan view of the tire side portion.

[0028] In the above configuration, the ridge region 4, which is composed of multiple ridges 41 extending in the tire radial direction, is positioned to cover the turned-up end 131e of the carcass ply 131. This reduces residual air near the turned-up end 131e of the carcass ply 131 during the tire vulcanization process, thereby suppressing poor tire side appearance (so-called light failure) due to residual air. Specifically, near the turned-up end 131e of the carcass ply 131, rubber flow tends to deteriorate during the tire vulcanization process, resulting in residual air. This tendency is particularly pronounced in tire structures in which the rubber gauge in the sidewall is thinned for the purpose of reducing tire weight. Therefore, by having a tire vulcanization mold with an uneven portion for forming the multiple ridges 41 extending in the tire radial direction and positioning this uneven portion at the position of the turned-up end 131e of the carcass ply 131, rubber flow near the turned-up end 131e of the carcass ply 131 is promoted and residual air is reduced.

[0029] For example, in the configuration of FIG. 2, as shown in FIG. 4, the ridge region 4 extends continuously around the entire circumference of the tire side portion, covering the entire circumference of the turned-up end 131e of the carcass ply 131. Also, a single, band-shaped ridge region 4 is arranged in a smooth region having a smooth surface and extends in the tire circumferential direction. This configuration is preferable because the ridge region 4 effectively reduces residual air. However, this is not limiting; the tire side portion may include multiple ridge regions (not shown), and at least one of these ridge regions may be arranged to cover the turned-up end 131e of at least one layer of carcass ply 131 in a plan view of the tire side portion.

[0030] It is also preferable that the turned-up end 131e of the carcass ply 131 is located in the radial center of the ridge region 4. Specifically, in Fig. 3, the radial height He from the radially inner edge of the ridge region 4 to the turned-up end 131e of the carcass ply 131, relative to the radial height H4 of the ridge region 4, is in the range of 0.25 ≦ He / H4 ≦ 0.75, and preferably in the range of 0.30 ≦ He / H4 ≦ 0.70.

[0031] The radial heights He and H4 are measured as the distance in the radial direction of the tire when the tire is mounted on a specified rim, pressurized to a specified internal pressure, and in an unloaded state.

[0032] 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 pressure" 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.

[0033] 2, the distance H31 from the rim diameter measurement point to the turned-up end 131e of at least one carcass ply 131 is in the range of 0.20≦H31 / SH≦0.60 relative to the tire cross-sectional height SH. Since residual air is likely to be generated in the region where the ratio H31 / SH is in the above range, by applying this structure to a tire, the ridge region 4 can effectively reduce residual air.

[0034] The tire section height SH is half the distance between the tire outer diameter and the rim diameter, and is measured with the tire mounted on a specified rim, with the specified internal pressure applied, and with no load applied.

[0035] It is also preferable that the tire cross-sectional height SH is 100 [mm]≦SH.

[0036] 2, the first carcass ply 131 is wound around the entire bead core 11 and the bead filler 12 and is in self-contact with the main body portion 131m. Also, a turned-up end portion 131e of the first carcass ply 131 is located between the radially outer end portion of the bead filler 12 and the tire maximum width position A.

[0037] 2, the distance H4A from the rim diameter measurement point to the radially inner edge of the ridge region 4 is in the range of 0.10≦H4A / SH, where SH is the tire cross-sectional height. It is also preferable that the radially inner edge of the ridge region 4 be located radially outward of the rim check line (not shown). This reduces impact between the ridge region 4 and the rim flange.

[0038] Furthermore, it is preferable that the ridge region 4 is disposed so as to cover the radially outer end of the bead filler 12 in a plan view of the tire side portion (not shown). Specifically, the radially inner edge of the ridge region 4 is located radially inward of the radially outer edge of the bead filler 12. This reduces residual air near the edge of the bead filler 12, thereby suppressing poor appearance of the tire side portion due to residual air.

[0039] 2, the distance H4B from the rim diameter measurement point to the radially outer edge of the ridge region 4 is in the range of H4B / SH≦0.70 relative to the tire cross-sectional height SH. The radially outer edge of the ridge region 4 is located radially inward of the tire ground contact edge T and radially inward of the mold parting position M of the tire vulcanization mold. In the configuration of FIG. 2, the radially outer edge of the ridge region 4 is located radially inward of the tire maximum width position A. Therefore, the ridge region 4 does not intersect with the tire maximum width position A.

[0040] The distances H4A and H4B of the ridge region 4 are measured as distances in the tire radial direction when the tire is mounted on a specified rim, a specified internal pressure is applied, and the tire is in an unloaded state.

[0041] 3, the radial height H4 of the ridge region 4, relative to the tire cross-sectional height SH, is in the range of 0.05≦H4 / SH≦0.20, and preferably 0.10≦H4 / SH≦0.18. The above lower limit ensures the radial height H4 of the ridge region 4, ensuring the effect of the ridge region 4 in reducing residual air. The above upper limit prevents a decrease in rigidity in the tire sidewalls due to the ridge region 4 being too large.

[0042] 3, the radial height He from the radially inner edge of the ridge region 4 to the turned-up end 131e of the carcass ply 131 is in the range of 0.25≦He / H4≦0.75, and preferably 0.30≦He / H4≦0.70, relative to the radial height H4 of the ridge region 4. Therefore, the turned-up end 131e of the carcass ply 131 is positioned in the center of the ridge region 4. This improves the residual air reduction effect of the ridge region 4.

[0043] 3, the distance T1 from the turned-up end 131e of the carcass ply 131 to the maximum depth position of the ridge region, relative to the distance T2 from the turned-up end 131e to the reference profile Pf, is in the range of T1 / T2≦0.80, and preferably T1 / T2≦0.60. This ensures the depth of the ridge region 4 at the turned-up end 131e of the carcass ply 131 (dimension symbols omitted in the figure: equivalent to the difference T2−T1), ensuring the residual air reduction effect of the ridge region 4. There is no particular lower limit for the ratio T1 / T2, but it is restricted by the lower limit of the rubber gauge T1, which will be described later.

[0044] The distance T1 from the turned-up end 131e to the bottom surface of the ridge region 4 is measured as the thickness of the sidewall rubber 16 on a perpendicular line (see FIG. 3; reference numerals are omitted in the figure) drawn from the turned-up end 131e to the reference profile Pf. Therefore, the distance T1 is measured excluding the coating rubber of the carcass plies 131, 132.

[0045] The distance T2 from the turned-up end 131e to the reference profile Pf is measured as the reference thickness of the sidewall rubber 16 on a perpendicular line (see FIG. 3; reference numerals are omitted in the figure) drawn from the turned-up end 131e to the reference profile Pf, i.e., the thickness of the sidewall rubber 16 in the absence of the ridge region 4. Therefore, the distance T1 is measured excluding the coating rubber of the carcass plies 131, 132.

[0046] 3, the distance T1 from the turned-up end 131e of the carcass ply 131 to the bottom surface of the ridge region 4 is in the range of 1.0 mm ≦ T1, and preferably in the range of 1.5 mm ≦ T1. This ensures the thickness of the sidewall rubber 16 and prevents the carcass layer 13 from being exposed. There is no particular upper limit to the distance T1, but it is restricted by the ratio T1 / T2. From the perspective of reducing the tire weight, it is preferable that the distance T1 be in the range of T1 ≦ 2.0 mm.

[0047] 3, the distance T2 from the turned-up end 131e of the carcass ply 131 to the reference profile Pf is in the range of 2.5 mm≦T2≦3.5 mm, and preferably in the range of 2.5 mm≦T2≦3.0 mm. The lower limit ensures durability of the tire sidewalls, and the upper limit prevents deterioration of rolling resistance due to an increase in tire weight.

[0048] In the configuration of FIG. 2, the ridge region 4 is made up of a plurality of ridges 41 and a housing 42, as shown in FIGS.

[0049] The housing 42 is a frame-shaped recess formed in the tire side portion, and is defined as a recess or groove that is recessed with respect to the reference profile Pf, that is, the profile that is the reference for tire design.

[0050] The reference profile Pf is a contour line that approximates the outer surface of the sidewall from the bead portion to the buttress portion in a cross-sectional view in the tire meridian direction, using multiple continuous arcs, and is measured excluding partial unevenness formed on the tire side (for example, surface finishes such as patterns, stampings such as letters, side blocks, rim protectors, mold split marks, etc.).

[0051] The tire profile is the outline of the tire in a cross section taken along the tire meridian, and is measured using a laser profiler, such as a tire profile measuring device (manufactured by Matsuo Corporation).

[0052] For example, in the configuration of Fig. 5, the multiple ridges 41 extend longitudinally in the tire radial direction. The multiple ridges 41 are inclined at a predetermined inclination angle θ41 (see Fig. 6) with respect to the tire circumferential direction. The multiple ridges 41 traverse the housing 42 in the radial direction, and are connected at both ends to both radial walls of the housing 42. The multiple ridges 41 are arranged in the tire circumferential direction and filled into the housing 42.

[0053] 5, the pitch length P41 of the ridges 41 is in the range of 0.5 mm≦P41≦5.0 mm, and preferably in the range of 2.0 mm≦P41≦3.0 mm. The lower limit ensures a gap between adjacent ridges 41, 41, thereby realizing a lighter tire, while the upper limit ensures the number of pitches of the multiple ridges 41, thereby ensuring the effect of the ridges 41 in reducing residual air.

[0054] 6, the inclination angle θ41 of the ridge 41 relative to the tire radial direction is in the range of −30 degrees ≦ θ41 ≦ 30 degrees, and preferably in the range of −15 degrees ≦ θ41 ≦ 15 degrees. This ensures that the ridge 41 extends in the tire radial direction and thereby reduces residual air.

[0055] The inclination angle θ41 of the ridge 41 is measured as the angle between an imaginary line passing through both ends of the ridge 41 and the tire radial direction in a plan view of the tire side portion.

[0056] 6, the maximum width W41 of the ridge 41 is in the range of 0.20≦W41 / P41≦1.00, preferably 0.40≦W41 / P41≦1.00, relative to the pitch length P41 of the ridge 41 (see FIG. 5). This ensures that the ridge 41 can effectively reduce residual air. The maximum width W41 of the ridge 41 is in the range of 1.0 mm≦W42≦2.0 mm, preferably 0.4 mm≦W42≦0.8 mm.

[0057] The maximum width W41 of the ridge 41 is measured as the maximum value of the width in a cross section perpendicular to the longitudinal direction of the ridge 41.

[0058] 7, the maximum height H41 of the ridge 41 is in the range of H41 / H42≦1.00 relative to the maximum depth H42 of the housing 42. Therefore, the entire ridge 41 is embedded within the housing 42 without protruding from the housing 42. This reduces the air resistance of the tire. The maximum height H41 of the ridge 41 is in the range of 0.5 mm≦H42≦1.5 mm, and preferably in the range of 0.5 mm≦H42≦0.8 mm.

[0059] The maximum height H41 of the ridge 41 is defined as the maximum distance from the top of the ridge 41 to the bottom surface of the housing 42, as shown in Figure 7, and specifically, is measured as the maximum distance from the top of the ridge 41 to the bottom of the valley between adjacent ridges 41, 22.

[0060] The maximum depth H42 of the housing 42 is defined as the maximum distance from the edge of the housing 42 to the bottom surface of the housing 42, specifically, it is measured as the maximum distance from the edge of the housing 42 to the bottom of the valley between adjacent ridges 41, 41.

[0061] 8, the ridges 41 preferably have a cross-sectional shape that narrows from the base to the top. The maximum height H41 of the ridges 41, relative to the maximum width H41 of the ridges 41, is in the range of 0.25≦H41 / W41≦1.50, and preferably 0.50≦H41 / W41≦1.00. This ensures that the ridges 41 can effectively reduce residual air.

[0062] [Reduction of ridge] 5 to 7, each of the multiple ridges 41 has a reduced structure in which the cross-sectional area is reduced toward the center in the longitudinal direction of the ridge 41. A position Pm where the cross-sectional area of ​​the ridge 41 is minimal is defined.

[0063] At this time, the radial distance Dc (see FIG. 3) between the position Pm where the cross-sectional area of ​​the ridge 41 is minimum and the turned-up end 131e of the carcass ply 131 is in the range of -0.10≦Dc / SH≦0.10, and preferably -0.05≦Dc / SH≦0.05, relative to the tire cross-sectional height SH (see FIG. 2). With this configuration, the tire vulcanization mold has a protrusion at the position Pm where the cross-sectional area of ​​the ridge 41 is minimum, and by positioning this protrusion near the turned-up end 131e of the carcass ply 131, rubber flow near the turned-up end 131e of the carcass ply 131 is promoted, effectively reducing residual air.

[0064] Furthermore, because the ridge 41 has a constant cross-sectional shape at its center, the position Pm at which the cross-sectional area of ​​the ridge 41 is minimal has a predetermined length Lm in the longitudinal direction of the ridge 41. This length Lm, relative to the radial length L41 of the ridge 41, is in the range of 0.20≦Lm / L41≦0.80, and preferably in the range of 0.30≦He / H4≦0.70. The above lower limit improves the effect of the ridge 41 in reducing residual air, and the above upper limit suppresses the occurrence of cracks at the position Pm at which the cross-sectional area of ​​the ridge 41 is minimal.

[0065] The minimum value of the cross-sectional area of ​​the ridge 41 is in the range of 0 mm^2 or more to 3.0 mm^2 or less, preferably in the range of 1.0 mm^2 or more to 1.5 mm^2 or less. The ratio of the minimum value to the maximum value of the cross-sectional area of ​​the ridge 41 is in the range of 0 to 0.80 or less, preferably in the range of 0 to 0.50 or less. The lower limit ensures that the ridge 41 reduces residual air, while the upper limit ensures that the reduced structure of the ridge 41 promotes rubber flow.

[0066] For example, in the configuration of Fig. 5, the height and width of each of the multiple ridges 41 gradually decrease in a tapered manner toward the center in the longitudinal direction of the ridge 41, so that the cross-sectional area of ​​the ridge 41 monotonically decreases from both ends in the longitudinal direction of the ridge 41 toward the center. Also, as shown in Figs. 6 and 7, the height and width of the ridge 41 are constant at the center of the ridge 41, so that the position Pm where the cross-sectional area of ​​the ridge 41 is minimal has a predetermined length Lm in the longitudinal direction of the ridge 41. This promotes the flow of residual air from both ends of the ridge 41 to the center during tire vulcanization.

[0067] 6, the minimum width Wm of the base of the ridge 41, i.e., the connection between the bottom surface of the ridge 41 and the bottom surface of the housing 42, is in the range of 0.1 mm ≦ Wm ≦ 1.0 mm. Furthermore, the minimum width Wm of the base of the ridge 41 is in the range of 0.1 mm ≦ W41 - Wm, and preferably in the range of 0.2 mm ≦ W41 - Wm, relative to the maximum width W41 of the base of the ridge 41. This promotes the flow of residual air from both ends of the ridge 41 to the center during tire vulcanization. There is no particular upper limit to the difference W41 - Wm, but it is constrained by the numerical ranges of the width W41 and Wm.

[0068] 7, the minimum height Hm of the ridge 41 is in the range of 0.5 mm≦Hm≦1.0 mm. Furthermore, the minimum height Hm of the ridge 41 is in the range of 0 mm≦H41-Hm, preferably 0.2 mm, relative to the maximum height H41 of the ridge 41. This promotes the flow of residual air from both ends of the ridge 41 to the center during tire vulcanization. There is no upper limit to the difference H41-Hm, but it is constrained by the numerical ranges of the heights H41 and Hm.

[0069] 5, as described above, both the width and height of the ridge 41 gradually decrease from both ends toward the center in the longitudinal direction of the ridge 41. However, this is not limiting, and either the width or the height of the ridge 41 may gradually decrease from both ends toward the center in the longitudinal direction of the ridge 41 (not shown).

[0070] 5, the ridge 41 has a point-symmetric structure. However, this is not a limitation, and the ridge 41 may have an asymmetric structure in the longitudinal direction and / or width direction (not shown). In addition, in the configuration of FIG. 5, the position Pm at which the cross-sectional area of ​​the ridge 41 is at its minimum is located at a position including the midpoint of the ridge 41 in the longitudinal direction (reference numeral omitted in the figure). However, this is not a limitation, and the position Pm at the minimum may be located at a position offset from the midpoint of the ridge 41 in the longitudinal direction by being unevenly distributed to one side of the ridge 41 in the longitudinal direction.

[0071] [Variations] Fig. 9 is an explanatory diagram showing a modified example of the ridge 41 shown in Fig. 5. In this figure, the same components as those shown in Fig. 5 are given the same reference numerals, and the description thereof will be omitted.

[0072] In the configuration shown in FIG. 5, the ridge 41 has a trapezoidal ridgeline in a cross section taken along the tire meridian line, so that the position Pm at which the cross-sectional area of ​​the ridge 41 is minimal has a predetermined length Lm (see FIG. 6) in the longitudinal direction of the ridge 41. The turned-up end 131e of the carcass ply 131 is located within the range of the position Pm having this length Lm. Therefore, the radial distance Dc between the position Pm at which the cross-sectional area of ​​the ridge 41 is minimal and the turned-up end 131e of the carcass ply 131 is Dc = 0. This configuration is advantageous in that the ridge 41 has a region where the cross-sectional area is constant, making it easier to align the position Pm at which the cross-sectional area is minimal with the turned-up end 131e of the carcass ply 131.

[0073] However, this is not limiting, and as shown in Fig. 9, the position Pm where the cross-sectional area of ​​the ridge 41 is minimum may be a point, and therefore the length Lm may be 0. For example, in the configuration of Fig. 9, the ridge 41 has a V-shaped ridgeline when viewed in a cross section in the tire meridian direction, and the position Pm where the cross-sectional area of ​​the ridge 41 is minimum is located at the apex of the V-shape. In this case, it is preferable that the position Pm where the cross-sectional area of ​​the ridge 41 is minimum is in the range of -0.10≦Dc / SH≦0.10 with respect to the tire cross-sectional height SH (see Fig. 2), as described above. This ensures the ridge 41's effect of reducing residual air.

[0074] 10 to 14 are explanatory diagrams showing modified examples of the ridge 41 shown in Fig. 8. In these figures, the same components as those shown in Fig. 8 are given the same reference numerals, and the description thereof will be omitted.

[0075] In the configuration of FIG. 8, the ridge 41 has a triangular cross-sectional shape that narrows from the base to the apex.

[0076] However, the ridge 41 is not limited to this and may have a cross-sectional shape such as a trapezoidal shape (Figure 10) with a narrowing width from the base to the apex, a rectangular shape with a chamfered edge on the apex side (Figures 11 and 12), a pentagonal shape (Figure 13), or a rectangular shape with an arc-shaped apex (Figure 14).

[0077] [effect] As described above, [1] the tire 1 includes a pair of bead cores 11, 11, a carcass layer 13 spanning the pair of bead cores 11, 11, and a tire side portion made of a rubber member including a sidewall rubber 16 (see FIG. 1). The carcass layer 13 includes at least one carcass ply 131 wound back toward the outside in the tire width direction so as to encase the pair of bead cores 11, 11 (see FIG. 2). The tire side portion includes a ridge region 4 formed by arranging a plurality of ridges 41 extending in the tire radial direction in the tire circumferential direction (see FIG. 5). The ridge region 4 is arranged to cover a turned-up end 131e of at least one carcass ply 131 in a plan view of the tire side portion (see FIGS. 3 and 5).

[0078] In this configuration, the ridge region 4, consisting of multiple ridges 41 extending in the tire radial direction, is positioned to cover the turned-up end 131e of the carcass ply 131. This reduces residual air near the turned-up end 131e of the carcass ply 131 during the tire vulcanization process, thereby advantageously suppressing poor tire side appearance (so-called light failure) due to residual air. Specifically, near the turned-up end 131e of the carcass ply 131, rubber flow tends to deteriorate during the tire vulcanization process, resulting in residual air. This tendency is particularly pronounced in tire structures in which the rubber gauge in the sidewall is thinned for the purpose of reducing tire weight. Therefore, by having a tire vulcanization mold with concave and convex portions for forming the multiple ridges 41 extending in the tire radial direction and positioning this concave and convex portion at the position of the turned-up end 131e of the carcass ply 131, rubber flow near the turned-up end 131e of the carcass ply 131 is promoted, thereby reducing residual air.

[0079] [2] In the tire 1 described in [1] above, the radial height H4 (see FIG. 3) of the ridge region 4 is in the range of 0.05≦H4 / SH≦0.20 relative to the tire cross-sectional height SH (see FIG. 2). The lower limit ensures the radial height H4 of the ridge region 4, ensuring the effect of the ridge region 4 in reducing residual air, while the upper limit has the advantage of suppressing a decrease in rigidity of the tire side portion caused by the ridge region 4 being excessively large.

[0080] [3] In the tire 1 described in [1] or [2] above, the distance H31 from the rim diameter measurement point to the turned-up end 131e of at least one carcass ply 131 is in the range of 0.20≦H31 / SH≦0.60 relative to the tire cross-sectional height SH (see FIG. 2). Since residual air is likely to be generated in the region where the ratio H31 / SH is in the above range, applying this structure to a tire has the advantage of effectively obtaining the residual air reducing effect of the ridge region 4.

[0081] [4] In the tire 1 described in any one of [1] to [3] above, the plurality of ridges 41 have a tapered structure in which the cross-sectional area of ​​each ridge 41 is reduced toward the longitudinal center of the ridge 41 (see FIGS. 7 to 9). The radial distance Dc (see FIG. 3) between the position Pm at which the cross-sectional area of ​​the ridge 41 is minimal and the turned-up end 131e of at least one carcass ply 131 is within the range of −0.10≦Dc / SH≦0.10 relative to the tire cross-sectional height SH (see FIG. 2). This configuration has the advantage that the tire vulcanization mold has a protrusion at the position Pm at which the cross-sectional area of ​​the ridge 41 is minimal, and the protrusion is positioned near the turned-up end 131e of the carcass ply 131, thereby promoting rubber flow near the turned-up end 131e of the carcass ply 131 and effectively reducing residual air.

[0082] [5] In the tire 1 described in [4] above, the cross-sectional area of ​​the ridge 41 gradually decreases from the ends toward the center of the ridge 41 (see FIGS. 7 to 9). This has the advantage of promoting the flow of residual air from the ends of the ridge 41 to the center during vulcanization molding of the tire.

[0083] [6] In the tire 1 described in [4] or [5] above, the minimum value of the cross-sectional area of ​​the ridge 41 is in the range of 0 [mm^2] to 3.0 [mm^2]. The lower limit ensures the effect of the ridge 41 in reducing residual air, while the upper limit ensures the effect of promoting rubber flow due to the reduced structure of the ridge 41.

[0084] [7] In the tire 1, the ratio of the minimum value to the maximum value of the cross-sectional area of ​​the ridge 41 is in the range of 0 to 0.80 inclusive, in the tire 1 described in any one of [4] to [6] above. The lower limit ensures the effect of the ridge 41 in reducing residual air, and the upper limit has the advantage of ensuring the effect of promoting rubber flow due to the reduced structure of the ridge 41.

[0085] [8] In the tire 1 described in [4] above, the width of the base of the ridge 41 decreases toward the center in the longitudinal direction of the ridge 41 (see FIG. 6). This has the advantage of promoting the flow of residual air toward the center of the ridge 41 during vulcanization molding of the tire.

[0086] [9] In the tire 1 described in [8] above, the minimum width Wm (see FIG. 6) of the base of the ridge 41 is in the range of 0.1 mm≦Wm≦1.0 mm. This has the advantage of promoting the flow of residual air to the center of the ridge 41 during vulcanization molding of the tire.

[0087]

[10] In the tire 1 described in [4] above, the height of the ridge 41 decreases toward the center in the longitudinal direction of the ridge 41 (see FIG. 7). This has the advantage of promoting the flow of residual air toward the center of the ridge 41 during vulcanization molding of the tire.

[0088]

[11] In the tire 1 described in

[10] above, the minimum height Hm of the ridge 41 (see FIG. 7) is in the range of 0.5 mm≦Hm≦1.0 mm. This has the advantage of promoting the flow of residual air to the center of the ridge 41 during vulcanization molding of the tire.

[0089]

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

[11] above, the distance T1 from the turned-up end 131e of at least one carcass ply 131 to the maximum depth position of the ridge region 4, relative to the distance T2 from the turned-up end 131e to the reference profile Pf, is in the range of T1 / T2≦0.80 (see FIG. 3 ). This ensures the depth of the ridge region 4 at the turned-up end 131e of the carcass ply 131 (dimension symbol omitted in the drawing: corresponds to the difference T2−T1), which has the advantage of ensuring the residual air reduction effect of the ridge region 4. [Example]

[0090] FIG. 15 is a table showing the results of performance tests on the tire according to the embodiment of the present invention.

[0091] In this performance test, several types of test tires were evaluated for (1) appearance performance and (2) durability performance. Test tires with a tire size of 235 / 60R18 107V were also prepared.

[0092] (1) In the evaluation of appearance performance, 1,000 test tires are produced, and the appearance defects of the tire sidewalls near the wrap-up end of the carcass layer are observed, and the incidence rate is calculated. In this evaluation, the smaller the numerical value, the lower the incidence rate of appearance defects, and therefore the more preferable it is.

[0093] (2) In the evaluation of durability performance, a test vehicle runs over a curb 110 mm high at a speed of 10 km / h and an approach angle of 30 degrees. Cracks (length and depth) in the sidewall of 1,000 tire samples are observed. Based on these observations, an index evaluation is performed with the comparative example set as the standard (100). The higher the index value, the better; a value of 98 or higher indicates adequate performance.

[0094] 1 to 4, and includes a ridge region 4 arranged to cover a turned-up end portion 131e of a carcass ply 131 in a plan view of the tire side portion. The tire cross-sectional height SH is 137 mm.

[0095] The test tire of the comparative example does not have the ridge region 4 in the tire side portion of the test tire of Example 1, and has a tire side surface that follows the reference profile Pr.

[0096] As the test results show, it is clear that the test tires of the examples can improve the appearance performance of the tire while maintaining the durability performance of the tire. [Explanation of symbols]

[0097] 1 tire; 11 bead core; 12 bead filler; 13 carcass layer; 131, 132 carcass ply; 131m main body portion; 131e turnup end portion; 14 belt layer; 141, 142 belt ply; 143 belt cover; 144 belt edge cover; 15 tread rubber; 16 sidewall rubber; 17 rim cushion rubber; 4 ridge area; 41 ridge; 42 housing

Claims

1. A tire comprising a pair of bead cores, a carcass layer spanning the pair of bead cores, and a tire side portion made of a rubber member including a sidewall rubber, the carcass layer includes at least one carcass ply wound back on the outer side in the tire width direction so as to enclose the pair of bead cores, The tire side portion has a ridge region formed by arranging a plurality of ridges extending in the tire radial direction in the tire circumferential direction, and A tire characterized in that the ridge region is arranged to cover a turned-up end portion of the at least one carcass ply in a plan view of the tire side portion.

2. The tire according to claim 1, wherein a radial height H4 of the ridge region and a tire section height SH are in a range of 0.05≦H4 / SH≦0.

20.

3. 2. The tire according to claim 1, wherein a distance H31 from a measurement point of the rim diameter to the turned-up end of the at least one carcass ply is in a range of 0.20≦H31 / SH≦0.60 relative to a tire section height SH.

4. 2. The tire according to claim 1, wherein the plurality of ridges have a reduced structure in which the cross-sectional area is reduced toward a center portion in the longitudinal direction of the ridge, and a radial distance Dc between a position where the cross-sectional area of ​​the ridge is at its minimum and a turned-up end portion of the at least one carcass ply is in a range of −0.10≦Dc / SH≦0.10 relative to a tire cross-sectional height SH.

5. 5. The tire of claim 4, wherein the cross-sectional area of ​​said ridge gradually decreases from the ends of said ridge toward said central portion.

6. The tire according to claim 4, wherein the minimum value of the cross-sectional area of ​​the ridge is in the range of 0 [mm^2] to 3.0 [mm^2].

7. 5. The tire according to claim 4, wherein a ratio of a minimum value to a maximum value of a cross-sectional area of ​​the ridge is in the range of 0 to 0.

80.

8. 5. The tire of claim 4, wherein the width of the base of said ridge decreases toward the longitudinal center of said ridge.

9. The tire according to claim 8, wherein a minimum width Wm of the base of the ridge is in the range of 0.1 mm≦Wm≦1.0 mm.

10. 5. The tire of claim 4, wherein the height of said ridge decreases toward the longitudinal center of said ridge.

11. The tire according to claim 10, wherein the minimum value Hm of the ridge height is in the range of 0.5 mm≦Hm≦1.0 mm.

12. 2. The tire according to claim 1, wherein a distance T1 from the turned-up end of the at least one carcass ply to a maximum depth position of the ridge region is in a range of T1 / T2≦0.80, relative to a distance T2 from the turned-up end to the reference profile.

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