The Yokohama Rubber Co., Ltd.

Ryohei Takemori

Yuki Sasaya

Masaaki Nagayasu

Atsushi Tanno

Jun Matsuda

Hiraku Kouda

Hiraku Koda

A pneumatic tire includes inner intermediate lug grooves having a length Land outer intermediate lug grooves having a length Lformed in inner and outer intermediate land portions, respectively, where lengths Land Lsatisfy L>L. Distances W, W, W, and Wfrom a tire equator to an inner shoulder main groove, an inner center main groove, an outer center main groove, and an outer shoulder main groove, respectively, satisfy 0.58≤W/Wi≤0.62, 0.20≤W/Wi≤0.24, 0.15≤W/Wo≤0.19, and 0.53≤W/Wo≤0.57 with respect to distances Wi, Wo from the tire equator to ground contact edges. A total value of a groove width WGof the inner shoulder main groove and a groove width WGof the inner center main groove is larger than a total value of a groove width WGof the outer center main groove and a groove width WGof the outer shoulder main groove.

Pneumatic tire

A tire includes first through fourth chamfered portions where tire width direction dimensions change in a tire circumferential direction formed along respective vehicle mounting outer edges of first through fourth circumferential main grooves. A second inclined groove adjacent to a vehicle mounting outermost position of the second chamfered portion is formed. A third inclined groove adjacent to a vehicle mounting outermost position of the third chamfered portion is formed. At least one circumferential narrow groove extending in the tire circumferential direction is formed in at least one of a first land portion and a second land portion.

Tire

In a pneumatic tire including a bead core, a first bead filler on an outer circumference of the bead core, a carcass turned up from an inner side to an outer side around the bead core and the first bead filler), and a second bead filler on an outer side of a turned up portion of the carcass, a height of an upper end of the first bead filler is 10%-30% of a cross-sectional height, a turned up end of the carcass is on a radially outer side of a maximum width position, an upper end of the second bead filler is between the upper end and the turned up end, the second bead filler has a shape tapered toward the radially outer side, and thicknesses G1 to G3 of the second bead filler at predetermined positions satisfy 0.5≤G2/G1≤0.8 and 0.4≤G3/G1≤0.6.

Provided is a run-flat tire. A first bead filler is disposed on an outer circumferential side of a bead core, a second bead filler is disposed on an outer side in a tire width direction of a turned up portion of the carcass layer along the turned up portion of the carcass layer, and a thickness G on a first reference line of a side reinforcing layer, a thickness G1 on a second reference line of the side reinforcing layer, and a thickness G2 on a third reference line of the side reinforcing layer satisfy the relationships of 0.8×G≤G1≤1.0×G and 0.5×G≤G2≤0.7×G.

Run-flat 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.

A pneumatic tire includes a tread development width TDW in a tread portion and a tire maximum width SW which satisfy 0.70≤TDW/SW≤0.75. A profile line forming an outer surface of a sidewall portion in a tire meridian cross-section includes at least three arcs having mutually different radii of curvature. In the profile line, a radius of curvature Rof an arc from a first point to a second point, a radius of curvature Rof an arc from the second point to a tire maximum width position, and a radius of curvature Rof an arc forming a portion on an inner side in the tire radial direction from the tire maximum width position satisfy R>R>R. A height SDH in the tire radial direction from a bead heel to the tire maximum width position and a tire cross-sectional height SH satisfy 0.47≤SDH/SH≤0.50.

A pneumatic tire is provided. A bead filler is disposed on an outer circumferential side of each bead core in bead portions, a side reinforcing layer having a crescent-shaped cross-section is disposed on an inner side in a tire width direction of a carcass layer in a sidewall portion, and as physical properties of a rubber that constitutes the side reinforcing layer and a rubber that constitutes the bead filler, a modulus at 100% elongation is in a range from 8.4 MPa to 10.2 MPa, a tan δ at 60° C. is in a range from 0.04 to 0.08, and JIS hardness at 20° C. is in the range from 75 to 79.

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.

Automobile tire

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.

A pneumatic tire is provided whereby superior driving performance on muddy ground, snowy roads, sandy land, and the like can be obtained. The pneumatic tire includes main grooves provided in shoulder regions of a tread portion and extending in a tire circumferential direction; a plurality of lug grooves extending outward in a tire width direction from the main grooves and reaching sidewall portions; and a plurality of blocks that is partitioned by the main grooves and the lug grooves. In this pneumatic tire, a raised portion protruding from the blocks is provided at an end portion on an outer side in the tire width direction of the blocks; and the raised portion extends in the tire circumferential direction so as to protrude into the lug grooves positioned on both sides of the raised portion.

Growing community of inventors

Hiratsuka, Japan

Ryohei Takemori