The Yokohama Rubber Co., Ltd.

Yuki Sasaya

Ryohei Takemori

Masaaki Nagayasu

Atsushi Tanno

Jun Matsuda

Hiraku Kouda

Hiraku Koda

Provided is a pneumatic tire with wet steering stability performance and dry steering stability performance enhanced in a well-balanced manner. A dimple group is composed of a plurality of dimples (to) disposed at intervals and aligned in a tire circumferential direction. When the minimum center-to-center distance between different dimples () in an identical dimple group is defined as K and the minimum center-to-center distance between dimples () in different dimple groups is defined as L, the ratio L/K is 3.5 or more and 10.0 or less and the minimum center-to-center distance L is 20 mm or more and equal to or less than a ground contact length.

Pneumatic tire

A pneumatic tire includes protrusion portions formed on at least one tire side portion of tire side portions located on both sides in a width direction, projecting from a tire side surface that is a surface of the tire side portion, and extending along the tire side surface, the protrusion portions having an angle α within a range of no less than 6% and no more than 50% of an angle of one round in a circumferential direction, the angle α being relative and in the circumferential direction between two protrusion portion end position lines that respectively extend in a radial direction through different end portions of both end portions in an extending direction of the protrusion portions, and the tire side portion having a thickness at a tire maximum width position within a range of no less than 2 mm and no more than 9 mm.

Provided is a pneumatic tire. At least one land portion is defined and formed by a plurality of circumferential main grooves provided in a tread surface. A main sipe including a body portion and a chamfered portion is formed in at least one side of the body portion. A branch sipe branching from the chamfered portion is provided. The depth of the body portion is equal to or greater than the depth of the branch sipe.

A pneumatic tire is provided. In a meridian cross-section, an external contour shape of the bead core is a polygon formed by common tangent lines of a plurality of circumferential portions of a bead wire, the external contour shape includes a single vertex located toward the outside in a tire radial direction, an internal angle formed by two sides sandwiching the vertex is an acute angle, a bottom side of the external contour shape is inclined with respect to the tire lateral direction by from 2&#xb0; to 9&#xb0;, and the carcass layer is bent and folded back along a circumference of the bead core in a bead portion, a folded back portion of the carcass layer from a position of an outer end of the bead core in the tire radial direction extends toward a sidewall portion in contact with a body portion.

Of layers configuring a bead core of a pneumatic tire, the width Wof one of the layers including the greatest number of rows, the width W, Wof other of the layers located respectively innermost and outermost in the radial direction satisfy W&#x3e;Wand W&#x2264;0.5&#xd7;W. The position of width Wis inward in the radial direction of the center of the bead core. A carcass is folded and curved along the bead core and extends toward sidewalls where a folded back portion of the carcass contacts a body of the carcass. A rubber occupancy ratio in a closed region formed by the body and the folded back portion is 0.1% to 15%. The cross-sectional area Sand hardness Hof a filler outward of the carcass in the lateral direction, and the cross-sectional area Sand the hardness Hof the side reinforcing layer satisfy 0.12&#x2264;(S&#xd7;H)/(S&#xd7;H)&#x2264;0.50.

In a cross-section of a pneumatic tire, a contour of the bead core is a polygon formed by tangent lines of circumferential portions of a bead wire, the contour includes a vertex with an acute angle and a bottom side opposite the vertex, the carcass layer is folded back along a circumference of the bead core in a bead portion, a folded back portion of the carcass layer from an outer end of the bead core extends in the radial direction, and a distance in the radial direction between a center of an arc profile of a tire outer surface and a straight line extending in the lateral direction through the vertex is within 20% of a radius r of the arc, and a distance in the lateral direction between the center of the arc and a straight line extending in the radial direction through the vertex is within 2r&#xb1;0.4r.

In a pneumatic tire including a side reinforcing layer, the maximum width Wof a bead core and the widths W, Wof the bead core at innermost and outermost sides in the radial direction, respectively, satisfy W&#x3e;Wand W&#xd7;W. Wis toward the inside of the center of the bead core in the radial direction. A carcass is folded and curved along the bead core, and a folded back portion of the carcass extends toward the sidewalls while contacting a body of the carcass. A rubber occupancy ratio in a region formed by the body and the folded back portion of the carcass is 0.1% to 15%. The cross-sectional area Sof a filler toward the outside of the carcass in the lateral direction, the hardness Hof the filler, the cross-sectional area Sof a side reinforcing layer and the hardness Hof the side reinforcing layer satisfy 0.15&#x2264;(S&#xd7;H)/(S&#xd7;H)&#x2264;0.60.

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Hiratsuka, Japan

Yuki Sasaya