Bridgestone Corporation

Tamotsu Matsunuma

Shigeo Makino

Tetsuhito Tsukagoshi

Hiroyuki Koseki

Kiyohito Kawasaki

Michitaka Sato

A large-size pneumatic radial tire for use on rough road is disclosed, which comprises as a tire reinforcement a carcass ply of cords arranged in a direction substantially perpendicular to the equatorial plane of the tire and a belt composed of at least three cord layers each containing steel cords embedded parallel to each other in rubber and arranged at a relatively small angle with respect to the equatorial plane of the tire, at least a pair of adjacent cord layers among which being piled one upon the other to cross their cords with each other at an angle of 15.degree.-30.degree. with respect to the equatorial plane. In this type of the tire, the outermost cord layer for the belt is a cord layer formed by embedding a plurality of twisted steel cords, each having a single layer construction of 1.times.3, 1.times.4 or 1.times.5 or a double layer construction with a core of 1 to 2 filaments obtained by twisting plural steel filaments shaped prior to the formation of cord, in rubber at a cord volume fraction of 5-40% so as to provide a sealing type penetration form wherein a portion of the cord having an inner space completely filled with the penetrated rubber and a length l.sub.1 is alternately connected with a portion of the cord having an inner space incompletely filled with the penetrated rubber and a length l.sub.2 in the longitudinal direction of the cord so as to satisfy l.sub.2 of not more than 10 mm and l.sub.1 /l.sub.2 of not less than 0.14.

Large-size pneumatic radial tire for use on rough road with belt having

A pneumatic radial tire comprising a belt portion disposed between the tread portion and the carcass portion wherein the belt portion is constituted by at least a pair of first belts, a second belt and a third belt which are arranged from radially inward to outward, the first, second and third belts having a first series, second series and third series of parallel cords embedded therein, respectively. The first belts being laterally spaced apart a predetermined lateral space symmetrically with respect to the mid-circumferential centerline and the cords thereof are disposed at an angle of between 40 to 60 degrees with respect to the mid-circumferential centerline. The spaced-apart first belts have opposite lateral ends which are located within less than 5 percent of a belt width of the third belt from the corresponding opposite lateral ends of the third belt, respectively. The first series of the cords of the first belt and the second series of the cords of the second belt are oriented in same directions, while the second series of the cords of the second belt and the third series of the cords of the third belt are oriented in opposite directions with each other.

Pneumatic radial tire

Automobile tire

Growing community of inventors

Urawa, Japan

Tamotsu Matsunuma