Bridgestone Corporation

Shizuo Iwasaki

Kazuo Oshima

Kazuo Hayashi

Norio Inada

Michitsugu Kikuchi

Naohiro Sasaka

Kazuo Yagawa

A wheel tread partof a tread is constituted of a longitudinal main grooveformed in a circumferential direction via a center of a width direction, a plurality of longitudinal subgroovesformed on both side parts of the longitudinal main groovein the circumferential direction, and a plurality of traverse groovesformed in a width direction to intersect the longitudinal main and subgrooves, and divided into a plurality of blocks. Each of the plurality of blocksis provided with a one-end-open sipe, and formed so that rigidity in the width direction can be higher in an end a of a center side region compared with an end b of a shoulder side region. Since the rigidity of the end a of the center side region is higher, a reaction force is generated in accordance with a steering angle from the start of changing the same.

Pneumatic radial tire with tread having blocks provided with sipes

A pneumatic tire comprises a tread portion, a pair of sidewall portions, a pair of bead portions, and at least one carcass ply toroidally extending between a pair of bead cores and wound around the bead core to form a turnup portion, in which a reinforcing rubber having substantially a crescent shape at its lateral section is disposed at an inside of the sidewall portion and a cord reinforcing layer containing cord(s) extending in a direction of approximately 90&deg; with respect to a radial line segment is disposed in at least a bead portion.

Pneumatic tire with sidewall reinforcing rubber and bead reinforcing layer of approximately circumferential cords

A pneumatic radial tire comprises a tread portion having a two-layer structure of a cap rubber layer disposed outward in the radial direction and a base rubber layer disposed inward in the radial direction, in which an outer surface of said base rubber layer in the radial direction being existent in a position corresponding to not less than 20% of a depth of a main groove formed in the tread portion outward from a bottom of the main groove in the radial direction, and the base rubber layer being compounded with a recrosslinking inhibition assistant and/or an inorganic compound powder.

Pneumatic radical tire having cap base tread

A pneumatic radial tire comprising a pair of bead portions and sidewall portions and a tread portion connecting the sidewalls. At least one radial carcass layer reinforcing said portions is positioned between two beads embedded in the bead portions. A belt comprises at least two layers having cords crossing each other from one layer to the next, a cap circumferentially wound having organic fiber cords therein and reinforcing rubber layers in an entire region of the side wall portions supporting a load of the tire having a crescent shaped cross section along an inner side of the carcass. At least one tie-element layer resisting force generated in width directions of the tire and having many cords oriented substantially orthogonally with respect to an equatorial plane of the tire is arranged between the belt and the cap.

Pneumatic tire including at least one tie-element layer with

A pneumatic radial tire including one or more belt layers, wherein cords are used as cords for reinforcing at least one belt layer. These cords are formed by impregnating and attaching a resin having a modulus in tension of not more than 150 kg/mm.sup.2 to bundles of cord-like fibers composed of a number of filaments having a tensile strength of not less than 15 g/d and a fineness of 1-15 deniers, an impregnated and attached amount of the filaments being in a range of 30% to 70 wt % relative to a weight of the filaments, and each of the cords has an elliptical or rectangular cross-section shape having an aspect ratio of a major axis (b)/a minor axis (a) being 1.5 to 5. Each of the bundles of the fibers are not twisted.

Pneumatic radial tires including fiber/resin belt cords having

A pneumatic radial tire comprises a belt comprised of plural belt layers, in which at least one belt layer is formed by arranging particular twisted cords, which are obtained by twisting particular filament-resin composite bodies, at a particular end count. In this tire, the weight is light, the rolling resistance and steering stability as well as the resistances to bending of belt cord in the rapid turning and breaking of belt cord in the running on bad road are considerably excellent.

Pneumatic radial tires including belt cords with filament resin

A low rolling resistance pneumatic radial tire having an improved appearance comprises a carcass composed of a single rubberized carcass ply containing cords therein. The carcass ply cord is a high tenacity vinylon cord having characteristics after vulcanization represented by the following equations: ##EQU1## Further, the carcass ply has the number of overlapped cords of not more than 15 at the shoulder portion in its joint portion.

Low rolling resistance pneumatic radial tires having an improved

A pneumatic radial tire having improved comfortability and durability comprises a belt composed of at least two belt reinforcing layers, one of which layers contains high strength and high modulus polyvinyl alcohol fiber cords having particular properties.

Pneumatic radial tires with improved polyvinyl alcohol belt cords

A pneumatic radial tire having a low noise and an improved cornering stability has a belt structure of at least two belt layers composed of at least one layer containing cords each obtained by twisting organic fibers and at least one layer containing steel cords, at least one of the organic fiber cord layers being interposed between the steel cord layer and a tread at a state that both transversely outermost end portions are folded inward. This organic fiber cord is a cord obtained by twisting high strength, high modulus polyvinyl alcohol fibers and has particular twisting coefficient and strength. The tire further satisfies a particular relation between a height of a turnup portion of a carcass ply around a bead portion and a tensile stress at 50% elongation of a bead filler rubber reinforcing the bead portion at room temperature.

Pneumatic radial tire having a folded belt including a polyvinyl alcohol

A pneumatic radial tire having improved cornering stability, service durability and rolling resistance is provided by using high-elasticity, high-strength vinylon fiber having specified elongation and strength as a cord material for at least one belt layer in a belt composed of at least two belt layers. Particularly, noise level can be reduced without damaging other tire performances by combining at least one layer of high-elasticity, high-strength vinylon fiber cords with at least one layer of steel cords as a belt of the tire.

Pneumatic radial tires with a folded belt and high strength vinylon

A pneumatic tire is reinforced with cords made of polyvinyl alcohol based fibers, and meets the following requirements:

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Kodaira, Japan

Shizuo Iwasaki