Sumitomo Rubber Industries Limited

Yasuo Mitarai

Naoki Yukawa

Kiyoto Maruoka

Takaaki Ishida

Yasuaki Kuniyasu

Kentaro Yagyu

In a pneumatic tireaccording to the present invention, in the vicinity of a beadportion, a main portionof a carcass plyis passed through the vicinity of a neutral surface. A tensile force and a compressive force applied to the main portionare small. In the tire, occurrence of pinch cut is suppressed. In addition, this structure alleviates a force applied to the main portioneven during run-flat running. In the tire, damage is less likely to occur even during run-flat running for a long period of time. The tirehas excellent run-flat durability. Furthermore, in the tire, an increase in the vertical stiffness constant or weight thereof is suppressed.

Pneumatic tire

In a tire, each load support layerextends from a side portionof the tireto a radially inner side of a beltat an inner side of a carcass. A ratio (SP/WB) of a width SP from an equator plane to an outer edgeof the load support layer, relative to a width WB from the equator plane to an edge of the belt, in an axial direction is equal to or greater than 0.1 and equal to or less than 0.6.

In a side reinforcing type tire, when a cross-sectional height of the tireis denoted by L, a height in a radial direction from a bead base line to an outer edge of a coreis denoted by HC, a point on a turned-up portionof a carcass plyat which point a height in the radial direction from the bead base line is 0.35 times of the height L is denoted by P, and a point on the turned-up portionat which point the height in the radial direction from the bead base line is equal to the height HC is denoted by P, the turned-up portionhas, between the point Pand the point P, a shape that is a curved line projecting inward in an axial direction, a straight line, or a combination thereof.

A pneumatic tire includes a side wall having a side surface and a roughened region formed on the side surface such that the roughened region is extending in circumferential direction. The roughened region includes lands and dimples formed between adjacent lands, the lands include first lands and second lands formed such that the first and second lands are alternately arrayed in the circumferential direction and the first and second lands are inclined relative to radial direction in opposite inclination directions, and the roughened region is formed such that when the tire is mounted on a normal rim and filled with air at normal inflation pressure, the roughened region has an outer periphery formed on radially inner side of position 30 mm away in radially inward direction from tire maximum-width position, and the roughened region has an inner periphery formed on radially outer side of radially outer edge of the rim.

[Object] To provide a pneumatic tirewhich is excellent in durability. [Solution] A tireincludes a tread, wings, sidewalls, clinch portions, beads, a carcass, support layers, a belt, a band, an inner liner, and chafers. Dimplesare formed on the sidewallthat is at an inner side in a width direction of a vehicle when the tire is mounted on the vehicle. No dimplesare formed on the sidewallthat is at an outer side in the width direction of the vehicle when the tire is mounted on the vehicle. The ratio (Ha/Hb) of a height Ha at an outer end, in a radial direction, of the beadfrom a base line BL relative to a height Hb at a maximum width position Pfrom the base line is equal to or greater than 0.80 but equal to or less than 1.10.

Run flat tire

A runflat tire comprises a tread portion, a pair of sidewall portions, a pair of bead portions each having a bead core therein, a carcass extending between the bead cores, and a sidewall reinforcing rubber disposed axially inside the carcass in each sidewall portion, wherein each sidewall reinforcing rubber is provided with a plurality of grooves extending on an axially inner surface thereof, each groove has a radially outer end and a radially inner end within the inner surface of the sidewall reinforcing rubber, the grooves are arranged in a circumferential direction of the tire, a length of the groove is in a range of from 30 to 50 mm, a width of the groove is in a range of from 10 to 20 mm and a circumferential pitch of the groove is in a range of from 25 to 60 mm.

Runflat tire

The invention relates to the heavy duty radial tire with a bead-wind structure. And carcass cords of the carcass extend while inclining to one side in the tire and the other-side inclined region that extends while inclining to the other side with a lowermost position of the bead core in the tire axial direction being substantially the center. Or, the reinforcing ply is similarly inclined as the carcass cords. With this arrangement, it is possible to improve engaging force of the carcass ply or the reinforcing ply to the bead cores so that shifts of the carcass ply in a blow-by direction can be effectively restricted. It is also an object to provide a heavy duty radial tire that is capable of restricting damages of the beads at the inner end positions A.

Growing community of inventors

Kobe, Japan

Yasuo Mitarai