Bridgestone Tire Company Limited

Ube Industries, Inc.

Bridgestone Corporation

Tamio Araki

Masaki Ogawa

Shinji Yamamoto

Koichi Kojima

Yutaka Yamaguchi

Nobuyuki Koizumi

Nobumasa Ikeda

Joji Yatsunami

Munetoshi Shimotake

Masami Hirano

A radial tire having excellent cornering stability and high-speed durability is disclosed. The tire has a belt composed of a first structural body, which consists of a single rubberized cord layer containing cords of twisted metal wires and is folded at both lengthwise end portions, and a second structural body consisting of at least one rubberized cord layer containing unextensible cords, wherein the cord of twisted metal wires used in the first structural body has a specifically limited twisting construction and a specifically limited elongation.

Radial tire having an improving durability

A pneumatic radial tire comprising a radial carcass and a belt superimposed about a crown of the carcass is disclosed. In this tire, the cord for the belt is a metallic cord comprising a core of two metallic wires and an outer layer of six metallic wires disposed about the core, all of these wires having the same diameter and twisting direction and a form ratio of 90.about.110%.

Pneumatic radial tire cord for belt

A pneumatic tire includes a tread, a pair of sidewalls and a pair of bead portions and further a carcass and a belt for reinforcing the tread, sidewalls and bead portions. The carcass consists of at least one layer of rubber coated cord ply whose organic fiber cords are arranged in parallel with each other in substantially radial surfaces of the tire. The belt consists of a rubber coated metal cord layer folded at least at one edge, whose metal cords are arranged in parallel with each other at relatively small angles with respect to an equatorial line of the tire. According to the invention, a reinforcing layer of at least one rubber coated layer is arranged in an inside of and in substantially intimate contact with the folded edge of the rubber coated metal cord layer of the belt and extending at least 7% of an overall width of the belt from a folded position of the belt. Cords of the reinforcing layer are organic fiber cords and are in parallel with each other at angles of 0.degree.-40.degree. with respect to the equatorial line of the tire.

Pneumatic tire

A pneumatic radial tire is disclosed, which comprises as a reinforcement a belt consisting of a first belt body composed of a single ply containing metal twisted cords arranged at an inclination angle of 5.degree.-25.degree. with respect to the equatorial plane of the tire and embedded in a coating rubber, both end portions in widthwise direction of which being folded on the remaining central base portion thereof, and a second belt body composed of at least one rubberized ply containing inextensible cords crossed with the cords in the base portion of the first belt body. In the first belt body, the coating rubber has a dynamic modulus of 160-400 kg/cm.sup.2 and a gauge of rubber interposed between the cords in the base portion and the cords in the folded portion is within a range of 1.3-4.5 times an average diameter of the cords and is not less than 2 times a gauge of the coating rubber located outside the cords in the base portion opposite to the folded portion.

Pneumatic radial tires

A pneumatic tire having a cap/base structured tread and having an improved resistance against heat build-up and an improved wear resistance at the end of the use can be obtained by forming a tread base rubber of the tire with a vulcanizate of a rubber composition comprising specifically limited amounts of short fibers of syndiotactic-1,2-polybutadiene having a maximum diameter of not more than 10.mu. and an average diameter of less than 1.mu., carbon black, sulfur and natural or synthetic rubber.

Pneumatic tire having an improved resistance against heat build-up

A pneumatic tire having an improved chipping resistant property is disclosed. In the tire, the tread portion is formed with a vulcanizate of a rubber composition comprising 3-40 parts by weight of short fibers of syndiotactic-1,2-polybutadiene, 30-100 parts by weight of carbon black and 0.2-5 parts by weight of a p-phenylenediamine type antioxidant, on a basis of 100 parts by weight of a rubber selected from natural rubber, synthetic rubber and a blend thereof in an optional blending ratio.

Pneumatic tire having an improved chipping resistant property employing

This invention relates to a composition comprising a polybutadiene rubber containing a polymer obtained by block or graft polymerization of cis-1,4-polybutadiene with syndiotactic (syn)-1,2-polybutadiene, alone or blended with the other diene rubber, said syn-1,2-polybutadiene being crystallized and in a short fiber-like shape, and a breaking resistance characteristic and reinforcement characteristic being considerably improved by specifying the diameter and length of said short fiber, which is suitable for various parts of tire or industrial materials, and further relates to a composition of said polybutadiene rubber to which a carbon black is added for preferably used as a chafer or tread of tire, and still further relates to said composition to which a carbon black and an antioxidant are added for preferably used as a rubber blend composition for side wall.

Polybutadiene rubber composition

A coating rubber composition for tire cords is disclosed. This composition is an unvulcanized rubber composition comprising 3-40 parts by weight of short fibers of syndiotactic-1,2-polybutadiene having a maximum diameter of not more than 10.mu. and an average diameter of less than 1.mu. and 30-120 parts by weight of carbon black, on a basis of 100 parts by weight of a rubber, and has a swelling value of not more than 140% in the extrusion at 100.degree. C.

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Musashino, Japan

Tamio Araki