Bridgestone Corporation

Masafumi Koide

Shinsaku Katayama

Ataka Takei

Takayuki Kurata

Makoto Ishiyama

Yoshio Kaji

Eisuke Seta

Masakazu Amano

Hiroyuki Katsuno

Satoshi Ishikawa

Koichi Ota

Yoshikage Sato

Masaki Wada

Jun Matsuzaki

Tatsuya Nakai

Ietomo Matsunaga

Tadashi Wakiyama

Shoji Hayashi

Takashi Kawai

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

An object is to improve noise performance of a tire while enhancing movement performance thereof. At least one of the land portions () includes an outer wall surface () positioned on a vehicle outer side, an inner wall surface () positioned on a vehicle inner side, a tread surface () on an outer side in a tire radial direction, an outer edge () of the tread surface () in contact with the outer wall surface (), and an inner edge () of the tread surface () in contact with the inner wall surface (). The tread surface () is formed in a convex shape which is smoothly curved between the outer edge () and the inner edge () and which has a top portion () most protruded outward in the tire radial direction, in a cross section of the land portion () in a tire width direction. A relationship of Do &#x3c;Di is satisfied when a distance between the top portion () and the outer edge () in the tire radial direction is denoted as Do, and a distance between the top portion () and the inner edge() in the tire radial direction is denoted as Di. The top portion () is positioned closer to the inner edge () side from a center (P) of the land portion () in the tire width direction.

Tire

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.

Pneumatic tire

An object of the present invention is to provide an inside drum-type tire testing device, which can significantly improve operability and test precision, reliably has strength high enough to eliminate any concern about strength thereof, and has relatively small size and significantly small floor-occupied area. Specifically, the present invention provides a tire testing device, comprising: an inside drum-type cylindrical rotating drum; a fixed support memberfor surrounding the rotating drumfrom the outer peripheral side of the drum via rotation guide means; and a linear motorprovided between the rotating drumand the fixed support member, for rotationally driving the rotating drum

Tire testing device

Tread portion of an automobile tire

Driving stability and durability is efficiently improved. Since a protecting layerembedded with reinforcing cordsis disposed between a treadand a belt reinforcing layer, both of the protecting layerand the belt reinforcing layerdecentrally bear a large bending force generated when a pneumatic tireruns on a sharp projection or a difference in level. As a result, even if reinforcing elementsin the belt reinforcing layerare extended by large tension due to fill internal pressure, increase of strain generated in the reinforcing elementscan be effectively suppressed.

The pneumatic tire for two-wheeled vehicles including a plurality of tread rubbers constituting a tread wherein a region occupying 15 to 35% in the center of a stretched tread width, which is obtained by stretching the tread with respect to a tire equatorial plane as the center, is defined as a tread central section; the remaining regions at both ends are defined as tread side sections; regions in the respective tread side sections each occupying 4 to 13% from the corresponding tread end toward the center of the stretched tread width are defined as side-section shoulder-end regions; and the remaining regions of the respective tread side sections are defined as side-section near-center regions, a modulus of the tread rubbers for the side-section shoulder-end regions at 100% elongation is smaller than a modulus of the tread rubbers for the side-section near-center regions at 100% elongation, at least at a tread surface.

Pneumatic tire for two-wheeled vehicle

A pneumatic tirehaving a toroidal carcassand a beltconsisting of belt layersarranged in the outer circumferential side of a crown portionof the carcass. Between the adjacent belt layers, the cordsare crossed with each other with respect to an equatorial plane E of the tire to form cross belt layers. The widest belt layeris a folded belt layer having a body portionand a folded portion. A cordconstituting the folded belt layeris an organic fiber cord. A narrow belt reinforcing layerof rubberized cordsis arranged at least immediately below the width terminal endof the body portionof the folded belt layerwhich terminal endabuts on the folded portion

Pneumatic tire with narrow belt reinforcing layer immediately below with terminal end of folded belt layer

A pneumatic tire for a motorcycle in which partial abrasion is suppressed by making the slip component of a tread lubber in the circumferential direction of tire as uniform as possible in the ground contacting plane. A cushion rubber layerhaving elastic modulus lower than that of the tread rubberis arranged on a spiral belt layer, and an inclination belt layerincluding a cord inclining at an angle of 45 to 90 degrees to the circumferential direction of the tire is arranged on the cushion rubber layer. Consequently, shear deformation of the cushion rubber layerduring traveling can be transmitted to the tread rubberafter being smoothed by the inclination belt layer. As compared with a case not provided with the cushion rubber layerand the inclination belt layer, shear deformation of the tread rubber layercan be reduced relatively because shear deformation occurs in the cushion rubber layerin place of the tread rubber; and since the slip component of the tread rubberin the circumferential direction of the tire becomes substantially uniform in the ground contacting plane, partial abrasion can be suppressed.

Growing community of inventors

Hidaka, Japan

Masafumi Koide