Bridgestone Corporation

Ataka Takei

Eisuke Seta

Takayuki Kurata

Shinsaku Katayama

Yoshio Kaji

Masafumi Koide

Masakazu Amano

Hiroyuki Katsuno

Yuki Watanabe

Tomoaki Ito

Shoko Nagamoto

Satoshi Ishikawa

Koichi Ota

Yoshikage Sato

Atsushi Watanabe

Akihiro Kawakita

In a tire, plural outer side cutouts, which respectively correspond to block land portions and extend toward tire width direction outer sides and end midway along outer side land portions, are formed so as to be spaced apart in a tire circumferential direction in tire width direction inner-side side walls, which are exposed to central circumferential grooves, of the outer side land portions that are provided further toward tire width direction outer sides than the two central circumferential grooves respectively. Further, at least portions of tire width direction inner side openings of the outer side cutouts are positioned between maximum position A, at which a tire width direction distance of a corresponding block land portion is a maximum, and an intermediate point B of two vertices that are adjacent at a tire width direction outer-side side wall of the block land portion.

Tire

A pneumatic tire includes a pair of circumferential grooves, a plurality of lateral grooves, and longitudinal grooves communicating between the lateral grooves on the outsides, in a tire width direction, of the circumferential grooves. Each lateral groove includes a lateral groove first portion, a lateral groove second portion disposed further outward, in the tire width direction, than the lateral groove first portion, and a lateral groove step portion connecting the lateral groove first portion and lateral groove second portion.

Pneumatic tire

A pneumatic tire (), which has, in the surface of the tread (), lug grooves () on one side extending from one axial edge towards the axial center of the tire in such a manner as to intersect with the circumferential direction of the tire and lug grooves () on the other side extending in a symmetrically opposite direction from the axial center towards the other axial edge of the tire, has at least one circumferential groove () extending circumferentially around the tire. Also, circumferential grooves () are so formed as to satisfy a relationship of '1&#x2264;(S/L)&#x2264;3' where L is the axial length of the central region, which is the region enclosed by two straight parallel lines each passing through the center between the contact width center (CL) and the contact edge with the shoulder regions being the regions axially outside of the parallel lines, and S is the total of the groove areas of the circumferential grooves () disposed in the central region. Therefore, the pneumatic tire () not only secures the steering stability performance on wet road surfaces, but also improves the steering stability and wear resistance performance on dry road surfaces.

Pneumatic tire having lug grooves forming a direction tread pattern

A pneumatic tire, having in a tread surface thereof a pair of circumferential grooves formed on respective sides of the tire equatorial plane in the middle, a rib-like central land portion row demarcated by the circumferential grooves, and a plurality of lateral grooves extending between the central land portion row and each tread end, comprises in each half region of the tread: a row of first intermediate blocks each having a circumferential length D2 and demarcated by the lateral grooves, the corresponding circumferential groove, and first longitudinal grooves; and a row of second intermediate blocks demarcated by the lateral grooves, the first longitudinal grooves, and second longitudinal grooves, wherein facing openings of the first/second longitudinal grooves adjacent in the tire circumferential direction are offset from each other, and provided that D1 represents a circumferential distance between adjacent ends of the adjacent first and second intermediate blocks, D1&#x2266;D2/2.

A pneumatic tire () has, in the surface of the tread (), a central circumferential groove () located at the center of the contact patch width and extending circumferentially around the tire, a plurality of longitudinal grooves (()) formed on the axially outside of the central circumferential groove (), lug grooves (), and blocks ((to)) defined by the central circumferential groove (), the longitudinal grooves (), and the lug grooves (). Each of the lug grooves () is formed such that its width in the shoulder region is greater than its width in the central region, and the sum of the groove area of the central circumferential groove () and the groove area of the longitudinal grooves () is smaller than the area of the lug grooves (). As a result, the pneumatic tire () not only secures the wet braking performance and wear resistance performance on paved roads, but also improves the acceleration performance and braking performance and the steering stability performance on snowy roads.

Tread of an automobile tire

Provided is a pneumatic tire used with a specified rotation direction, including a tread, a pair of sidewalls extending continuously from the tread inward in a tire radial direction, a pair of beads continuous with the sidewalls inward in the tire radial direction, and at least one ridge on a buttress surface. The buttress surface extends from a tread edge of a tread surface formed on the tread to the sidewall. The ridge extends from a sidewall side of the buttress surface towards the tread edge and terminates before reaching the tread edge. The ridge includes a steeply inclined surface, having a high gradient with respect to the buttress surface, inclined forwards in the rotation direction, and a moderately inclined surface, having a more moderate gradient than the steeply inclined surface, inclined backwards in the rotation direction.

First inclined grooves () and second inclined grooves () are formed on a land portion () of a tire. The first inclined grooves () and second inclined grooves () are alternately formed in the circumferential direction of the tire. Circumferential direction sipes () comprise: first circumferential direction sipes () that are formed extending from the end at the land portion () side of the first inclined grooves () to the central portion, in the tread width direction, of the second inclined grooves (); and second circumferential direction sipes () that extend from the central portion, in the tread width direction, of the second inclined grooves () along the extension line from the first circumferential sipes (). The second circumferential sipes () terminate in the land portion ().

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Tokyo, Japan

Ataka Takei