The Yokohama Rubber Co., Ltd.

Kazuyoshi Saneto

Akinori Tokieda

Hiroaki Matsuzaki

Hiroshi Tokizaki

Izumi Kuramochi

Masatoshi Kuwajima

Mitsutoshi Saeki

Motohide Takasugi

Takashi Yamashita

Daisuke Higashide

Kunihiko Kakigi

Hisamiti: Masaki

In a pneumatic tire having an asymmetric tread pattern in witch ribs continuing in a tire circumferential direction are disposed on a tread surface at a shoulder end portion on the outer side of a vehicle when the tire is fitted to the vehicle, and block lines each comprising a plurality of blocks are disposed at a shoulder end portion on the inner side of the vehicle, wherein sub-grooves extending in a tire width-wise direction while forming right and left pairs are disposed on the portion of the tire more inward than the ribs at a predetermined pitch in the tire circumferential direction and in a herringbone pattern widening in a direction opposite to a rotating direction of the tire, the apexes of the herringbone patterns are positioned on the outer side of the tire with respect to a tire equator line, and pairs of the right and left sub-grooves are made mutually discontinuous at the apexes.

Pneumatic tire having asymmetric tread pattern

A run-flat pneumatic radial tire having an aspect ratio of up to 50%, which includes a reinforcing liner layer made of a rubber having a complex modulus at 20.degree. C. E*.sub.20, a ratio of a complex modulus at 100.degree. C. to the complex modulus at 20.degree. C., a 100% modulus and a loss tangent (tan .delta.) at 100.degree. C. which satisfy certain specified numeric values. The liner has a crescent sectional shape and is disposed in sidewall portions of a carcass layer with its end portions overlapping the end portions of a belt layer and a bead filler having a specified hardness and height h from a wheel rim base. The carcass layer consists of an inner carcass layer turned up around the bead core from inside to outside the tire so that its end portion is positioned at a position higher than the height h of the bead filler and an outer carcass layer having an end portion disposed axially outward of the bead core.

Run-flat pneumatic radial tire

A run flat pneumatic radial tire having a flatness of 50% or less, comprising a reinforcing liner layer comprised of a high-hardness rubber having a crescent cross section disposed on the inside of a side wall portion and an inner liner layer comprising a rubber composition mainly composed of a butyl rubber provided all over the internal surface of the tire, wherein the inside of the inner liner layer in at least a region covering said reinforcing liner layer is covered with a rubber layer comprising a rubber composition mainly composed of a diene rubber having a polybutadiene rubber content of 50% by weight or more based on the rubber component.

Run flat pneumatic radial tire

A run-flat pneumatic radial tire having an aspect ratio of up to 50%, which includes a reinforcing liner layer mode of a rubber having a complex modulus at 20.degree. C. E*.sub.20, a ratio of a complex modulus at 100.degree. C. to the complex modulus at 20.degree. C., a 100% modulus and a loss tangent (tan .delta.) at 100.degree. C. which satisfy certain specified numeric values. The liner has a crescent sectional shape and is disposed in sidewall portions of a carcass layer with its end portions overlapping the end portions of a belt layer and a bead filler having a specified hardness and height h from a wheel rim base. The carcass layer consists of an inner carcass layer turned up around the bead core from inside to outside the tire so that its end portion is positioned at a position higher than the height h of the bead filler and an outer carcass layer having an end portion disposed axially outward of the bead core.

A radial tire comprising a pair of belt layer provided on a tread portion, a narrow reinforcing covers covering each of the edge portions of the belt layer, and a wide reinforcing cover provided on the narrow reinforcing covers so as to cover the full width of the belt layer, wherein the wide reinforcing cover has a multi-layer structure formed by winding a sheet in the circumferential direction of the tire so as to cause each successive layer to be put on top of a preceding layer.

Radial tire

In a tire tread pattern in which a plurality of block patterns are disposed on a tire tread surface in the circumferential direction and their pitch lengths are varied, lug grooves inside of said block patterns extend in the direction of a grounding width, and their angles relative to the direction of grounding width are varied in accordance with the change of the pitch lengths of said block patterns.

Tire tread pattern

A cord inclination angle of the outermost belt layer of a tire on the right side with respect to a tire running direction is arranged in such a manner as to be inclined leftwardly downward in the tire running direction while the cord inclination angle of the outermost belt layer of the left tire is arranged in such a manner as to be inclined rightwardly downward in the tire running direction. In addition, projecting bent portions of lug grooves on a tread pattern of a tire grounding surface are disposed outside from the center of a tread exploded width in the tire running direction.

Growing community of inventors

Hadano, Japan

Kazuyoshi Saneto