The Yokohama Rubber Co., Ltd.

Yasujiro Daisho

Izumi Kuramochi

Susumu Watanabe

Hiroshi Tokizaki

Takumi Morito

Masahiro Ebiko

Kohtaroh Iwabuchi

Hikomitsu Noji

Masaki Noro

Issey Nakakita

Automobile tire

At least one reinforcing rubber layer is provided in the part of each of two side wall portions which is on the outer side of a carcass layer. The outer circumferential end portions of the reinforcing rubber layers extend to positions in which they are disposed between the end portions of the innermost belt layer and the corresponding portions of the carcass layer, while the inner circumferential end portions of these rubber layers extend inward in the radial direction of the tire so as to overlap the bead fillers in positions on the outer sides of the end portions of the carcass layer in the widthwise direction of the tire. A 100% modulus at 100.degree. C. of the rubber constituting the reinforcing rubber layers is not higher than that of the rubber of the belt layers, and a dynamic elastic modulus at 20.degree. C. of the former rubber in the range of 10-40 MPa. The thickness of the portions of the reinforcing rubber layers which are between the edges of the innermost belt layer and the outer circumferential ends of the bead fillers is set securely to not less than 1.00 mm, and the thickness of the parts of the side wall portions which are on the tire outer sides of the reinforcing rubber layers also not less than 1.00 mm.

Pneumatic tire with sidewall reinforcing rubber layer

A pneumatic tire having a plurality of main grooves extending in the circumferential direction of a tread surface, and a plurality of auxiliary grooves each of which is disposed in the shape of the letter 'V' and extended in one of the circumferential directions of the tread surface, the apexes of the V-shaped auxiliary grooves being distributed in left and right regions each extending from the equator of the tire as much as 5-25% of the width of a ground contacting portion of the tread surface, in such a manner that the numbers of the apexes in the left and right regions become substantially equal to each other, characterized in that quasi-main grooves each of which connects at least two circumferentially arranged auxiliary grooves together are provided in left and right regions each extending from the equator of the tire as much as 25-50% of the width of a ground contacting portion of the tread surface, in such a manner that the quasi-main grooves are inclined at an angle of 5.degree.-25.degree. with respect to the equator of the tire.

Pneumatic tire

Growing community of inventors

Hiratsuka, Japan

Yasujiro Daisho