Sumitomo Rubber Industries Limited

Yasuaki Kuniyasu

Fumikazu Yamashita

Kentaro Yagyu

Naoki Yukawa

Tadao Matsumoto

Takaaki Ishida

Hiroaki Ninomiya

Yasutaka Iwata

Yasuo Mitarai

Yurie Tanami

Akira Kamigoro

Shingo Umekita

Yuma Watanabe

A pneumatic tire comprises: a bead portion provided with an inside bead apex rubber disposed between a turned up portion and a main portion of a carcass ply, and an outside bead apex rubber disposed axially outside the turned up portion and having a radially outer edge; and a the sidewall portion provided with a sidewall reinforcing cord layer disposed axially outside the carcass and having a radially inner edge which is spaced apart from the radially outer edge of the outside bead apex rubber by a radial distance of not less than 5% of a tire section height.

Pneumatic tire

In the tire, fillersare layered over clinchesin portions outward of a carcassin the axial direction. A carcass plyis turned up around cores. Turned-up portionsare disposed between the fillersand apexes. Each clinchhas a maximum thickness Tcx that is measured along a line normal to an inner surface, in the axial direction, of the clinch. A ratio of a thickness Tfof the fillerto a sum of the thickness Tfand the thickness Tcx is greater than or equal to 0.1 and not greater than 0.6. A percentage of a complex elastic modulus E*f of the fillerrelative to a complex elastic modulus E*a of the apexis greater than or equal to 70% and not greater than 125%.

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.

A pneumatic tire including bead apex rubbershaving a rubber hardness Hsof 80 to 95 and extending radially outward from bead cores, and clinch rubbershaving a rubber hardness Hsof 65 to 85 lower than the rubber hardness Hsand forming outer surfaces of bead portions. A carcassis formed of an inner carcass plyA comprising a body portionextending between bead coresand turnup portionswhich are continuous with the body portionand are turned up around the bead cores, and an outer carcass plyB comprising a body portionwhich extends along the outer surface of the body portion, and the radially inner ends of which are sandwiched between the body portionand the bead apex rubbersto terminate there. The turnup height Lc of the turnup portionfrom the bead base line BL is 60% or less of the tire section height L, and the height Ld of inner ends of the body portionis 60% or less of the height Lof the bead apex rubber

A pneumatic tire comprises a sidewall reinforcing rubber disposed axially inside the carcass in each of the sidewall portion, and in order improving the ride comfort during normal running without deteriorating runflat performance, the axially inner surface of the sidewall reinforcing rubber is provided with a circumferentially extending groove. When the tire is deflated, the groove in the ground contacting patch is closed and the sidewall reinforcing rubber supports the tire load. When the tire is inflated-normally, as the sidewall portion can be bent around the groove, the ride comfort is improved.

Growing community of inventors

Kobe, Japan

Yasuaki Kuniyasu