Bridgestone Tire Company Limited

Bridgestone Corporation

Isamu Imai

Norio Inada

Kazuo Oshima

Toshihiro Yotsumoto

Shigeyuki Toki

Maki Sato

Kazuo Koyama

Ichiro Wada

Mitsuaki Maeda

Junichi Ohtsuka

Kenichi Tanaka

Nobuo Sato

Rubber-reinforcing fiber cords are disclosed which are constituted by at least one kind of fibers selected from a group consisting of aromatic polyamide fibers, entire aromatic polyester fibers and polyvinylalcohol fibers having a tenacity of not less than 15 g/d. Spaces among filaments constituting the cord are each impreganted with a rubbery material. Radial tires are also disclosed which each comprise at least one pair of bead wires, at least one carcass ply cord layer and at least one belt ply cord layer. Carcass ply cords and/or belt ply cords are constituted by the above rubber-reinforcing fiber cords.

Heavy duty pneumatic radial tires using rubber reinforcing fiber cords

A heavy duty-high pressure pneumatic radial tires are disclosed, which each comprise a main reinforcement consisting of a carcass having an up-and-down type toroid radial construction in which a plurality of plies composed of fiber cords arranged in parallel with one another are turned up around a pair of bead cords on the right and left or the tire while the cords are arranged at angles substnatially along radial planes of the tire, at least one ply including a ply to be brought into direct contact with the bead cords being turned up around each of the bead cores from the inside to the outside of the tire and at least one remaining ply being laminated upon the outer side of the turn-up portion formed by the turn-up end portion of said at least one ply, and a belt which surrounds a crown portion of the carcass and is composed of a plurality of layers of parallel organic fiber cords having at least 150 g/d or an initial modulus higher than that of the cords of the carcass while at least one belt layer is laminated at an cord-arranged angle near substantially 0.degree. with respect to the crown circumference. The plies of the carcass are composed of organic fiber cords having a thermal shrinkage of not less than 1.0% and not more than 10% at 177.degree. C.

Heavy duty-high pressure pneumatic radial tires

A heavy duty pneumatic radial tire for use under a high speed and a high internal pressure, is disclosed, which comprises a plurality of carcass cord layers of which cords are arranged at an angle from 90.degree. to 75.degree. with respect to a circumferential direction of the tire. The cords are composed of fibers of an aromatic polyamide having not less than 80 mole % of a repeating unit expressed by the following formula: --NH--Ar.sub.1 --NHCO--Ar.sub.2 --CO-- in which Ar.sub.1 and Ar.sub.2 denote at least one kind of an aromatic residue selected from: ##STR1## Elongation E.sub.n (%) of the aromatic polyamide fibers constituting the respective plies meets the following inequation:

Heavy duty pneumatic tire

Rubber-reinforcing polyamide fiber cords are disclosed which are each obtained by primarily twisting an aromatic polyamide filament yarn, doubling a plurality of thus primarily twisted yarns and finally twisting doubled yarns in a twisting direction opposite to that of the primary twist yarn to obtain a plied yarn, and applying a rubber adhesive to the thus obtained plied yarn. N and M satisfy the following relation: 1.05.ltoreq.M/N.ltoreq.1.6 in which N and M are the number of primary twists and the number of the twists in the cord, respectively.

Rubber-reinforcing aromatic polyamide fiber cords

A pneumatic tire comprises an annular tread at a central portion, a pair of side wall portions, bead portions, a carcass extending between both bead wires, and a breaker composed of two or more cord layers with cords arranged at a cord angle of 5-60.degree. relative to the circumferential direction and between the tread and the carcass and intersecting in the adjacent plies. The cords constituting the carcass or the breaker are substantially made of polytetramethylene adipamide (4,6-nylon), and as buried in a rubber of the tire, have the following characteristics:

Pneumatic tire

A pneumatic radial tire is disclosed, which comprises a toroidal tire body extending from bead portions to a crown portion through sidewall portions, and a reinforcement for the tire body consisting of a carcass composed of at least one cord ply containing polyester fiber cords therein, which cord ply being wound around a bead core embedded in each of the bead portions from the inside of the tire to the outside thereof, and a belt composed of at least two ply layers superimposed around the crown portion of the carcass and containing cords arranged at a relatively small inclination angle with respect to the mid-circumferential plane of the tire, the cords of which being crossed with each other. In this type of the tire, the carcass line of the tire body at a mounted state of the tire on a normal rim under a normal internal pressure depicts such a radial profile in tire section that a ratio of R/R' is within a range of 0.65-0.85 in which R' is a radius of a reference arc BEC, and R is a radius of curvature of a contour curve FC in a shoulder portion of the carcass line, and that a maximum distance f between the reference arc and a contour curve in a base portion of the carcass line is within a range of 5-10 mm; and the polyester fiber cord has an elongation .DELTA.E under a tension of 2 g/d of not less than 5%, and a value of .DELTA.S+0.4.DELTA.E of not more than 5.0% in which .DELTA.S is a heat shrinkage of the cord.

Pneumatic radial tire

A pneumatic radial tire having a high durability is disclosed, which comprises a carcass composed of at least one ply containing polyester fiber cords embedded in rubber. This polyester fiber cord has particular fiber properties and cord properties. Among the cord properties, the elongation under a tension of 2 g/D of the cord after the specific post-cure inflation treatment is not more than 4.5% and the sum of the elongation and heat shrinkage is not more than 8.0%.

Pneumatic radial tires

Radial tires having improved irregular wear resistance, which are reinforced with a belt cord layer and a carcass cord layer, are disclosed. These radial tires have a crown radius of not less than a certain limited value and use, for at least the ground contact area of the tread, a rubber composition consisting essentially of 100 parts by weight of styrene-butadiene copolymer rubber having a viscosity average molecular weight of not less than 2.times.10.sup.5 or a blend rubber consisting of not less than 30 parts by weight of said copolymer rubber and at least one of natural rubber, polyisoprene rubber and polybutadiene rubber, 5-60 parts by weight of at least one of a liquid styrene-butadiene copolymer, a liquid polyisoprene and a liquid polybutadiene having a viscosity average molecular weight of 2.times.10.sup.3 -1.5.times.10.sup.5, and 40-90 parts by weight of carbon black.

Radial tires having improved irregular wear resistance

Radial tires having improved irregular wear resistance, which are reinforced with a belt cord layer and a carcass cord layer, characterized in that as the embedding rubber of the belt cord layer, use is made of natural rubber, polyisoprene rubber or a blend rubber consisting of said rubber and less than 30 parts by weight of at least one of polybutadiene rubber and styrene-butadiene copolymer rubber and that for the ground contact area of the tread of tire, a rubber composition consisting of 100 parts by weight of styrene-butadiene copolymer rubber having a viscosity average molecular weight of not less than 2.times.10.sup.5 or a blend rubber consisting of more than 50 parts by weight of said copolymer rubber and at least one of natural rubber, polyisoprene rubber and polybutadiene rubber, 5-60 parts by weight of at least one of a liquid styrene-butadiene copolymer, a liquid polyisoprene polymer and a liquid polybutadiene polymer having a viscosity average molecular weight of 5.times.10.sup.3 -7.times.10.sup.4, and 40-90 parts by weight of a carbon black, is used.

Radial tires having improved irregular wear resistance employing liquid

A tire having excellent withstand-voltage property, wear resistance and resistance against heat build-up is disclosed. The tire has a tread, at least the contact area of the tread with road surface being made of a rubber composition containing a specifically limited softening agent and a specifically limited carbon black.

Withstand-voltage tire

A pneumatic tire having a tread formed of a rubber composition consisting essentially of rubber and carbon black having specifically limited iodine adsorbability, dibutyl phthalate absorbability and tinting strength, has excellent cut resistance, chipping resistance, wear resistance and resistance against heat build-up, and is excellent in the running durability on both of paved road and off road.

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Tokorozawa, Japan

Isamu Imai