Bridgestone Corporation

Masatomo Oshima

Akihiko Sato

A tire vulcanizing mold for molding an unvulcanized tire into a pneumatic tire having a bead part with a bead heel part is provided with a side part ring for molding at least the bead part. A circumferential groove part extending in the tire circumferential direction is formed on a tire molding surface of the side part ring in a heel molding region for molding the bead heel part, the side part ring is divided into a side ring and a bead ring that abuts against the side ring, the division position of the tire molding surface of the side ring and the tire molding surface of the bead ring is located in the groove bottom of the circumferential groove part, and the cross-sectional shape of the circumferential groove part tapers toward the groove bottom.

Tire vulcanizing mold, tire manufacturing method, and tire

Motorcycle tire

A motorcycle tire includes, on an outer circumferential side of a crown region of a radial carcass, a belt layer, a single auxiliary belt layer, and a tread rubber in the stated order, a periphery width of the auxiliary belt layer being greater than a periphery width of the belt layer. The cords of the auxiliary belt layer extend in a direction in which an inclination angle of the cords of the auxiliary belt layer with respect to a tire circumferential direction gradually decreases from each of both ends of a tire equatorial region including a tire equatorial plane toward a corresponding &#xbc; position which is at a distance of &#xbc; of the periphery width of the auxiliary belt layer from the tire equatorial plane along a periphery of the auxiliary belt layer, and the inclination angle in the &#xbc; position is 60&#xb0; or more and 85&#xb0; or less.

The present invention has an object of providing a pneumatic tire having a tread pattern capable of providing both excellent drivability and a high partial wear resistance. The pneumatic tire of the present invention includes, in a tread surface, a compound groove partitioned into a first groove portion and a second groove portion by a first groove side and a second groove side, the first groove side having an oblique side portion diagonally disposed relative to a tire circumferential line in plan view, the second groove side intersecting with the oblique side portion of the first groove side at an acute angle in plan view, in which: the first groove portion and the second groove portion both have a groove depth that gradually reduces in an extending direction of the groove toward an intersection between the oblique side portion and the second groove side; and a groove wall extending from the first groove side is formed as a tapered surface mildly-sloped toward a groove bottom on the intersection side when viewed in the groove transverse direction. Further, the pneumatic tire of the present invention includes, in a tread surface, a groove partitioned by at least three groove sides in plan view, in which: one or more of groove walls extending from one of the at least three groove sides that extends in the longitudinal direction of the groove is formed as a tapered surface at least in part thereof; and the tapered surface forms an angle with a plane perpendicular to the tread surface, which varies in the extending direction of the groove side.

Pneumatic tire

A tire for two-wheeled motorcycles of the present invention includes a first carcass layer folded back along circumferential surfaces of bead cores, a second carcass layer folded back along circumferential surfaces of turnbacks of the first carcass layer, a belt layer wound spirally along a tire circumferential direction and an intermediate carcass layer provided between the first and second carcass layersand in an inner circumferential side of the belt layer and extending close to a tire maximum width.

Growing community of inventors

Kodaira, Japan

Masatomo Oshima