Bridgestone Corporation

Ryoichi Watabe

Yukihiro Kiwaki

Kenichi Shibata

Yoshio Kaji

Masahiro Katayama

Hiroyuki Katsuno

Kentaro Saeki

Makoto Kurokawa

Kazuyoshi Tagawa

Tooru Hayashi

Koujiro Yamaguchi

A pneumatic tire having enhanced on-ice braking performance achieved by further increasing the amount of water that can be sucked up into sipes. In the pneumatic tire, blocks () partitioned by circumferential grooves and lateral grooves are formed in the tread. A sipe () is formed in a block (), and a fine structure () having a height in the range of from 1/50 of the sipe width t to less than 1/10 of the sipe width t is formed on a sipe wall surface. This reduces fluid friction coefficient of water relative to the sipe wall surface to a lower level than conventional products. As a result, when water staying on ice comes into contact with the sipe wall surface, the water is more easily sucked up into the sipe. The construction increases the amount of water that can be sucked up into the sipe () or the removal amount of water that stays on ice etc., and this enhances braking performance (friction characteristics) on ice.

Pneumatic tire

The present invention provides a pneumatic radial tire which is, by effectively suppressing collapse-deformation of a relatively large magnitude in sectioned portions of each block, which sections are demarcated by sipes, and also effectively preventing the sipe from making narrowing-deformation, excellent in not only driving performance and braking performance on an icy or snowy road but also driving stability on a general road. The tire characteristically includes: a tread having a contact surface; plural circumferential grooves; plural lateral grooves; blocksdemarcated by the circumferential grooves and the lateral grooves in the contact surface of the tread; and plural sipesprovided in the blocks, wherein the bottom portion of each sipeis provided with at least one upward-protruding projectionfor integrally connecting respective facing groove walls of the sipe

Pneumatic radial tire with tread having blocks having waved sipes

The tread surface of a tire according to the present invention is molded with a tire mold having a tread molding surface, and at least a portion of the tread molding surface is formed by projecting spherical projection material having a predetermined sphericity and causing the spherical projection material to collide.

Tire mold, tire, and tire manufacturing method

Provided is a studless tire capable of achieving both the traction performance and the steering stability at the time of traveling on the ice and snow at a high level. A tread surfaceis disposed on the studless tire such that, among lateral groovesA,B,C,D,extending in an axial direction within each block arrayA,B,C,D, an axial length of a lateral grooveA,B,C,D opening to at least one straight circumferential grooveA,B adjacent to the block array provided with the lateral groove is referred to as a groove edge component, a proportion of the total length of the groove edge components on the inner tread surface IN to the total length of the groove edge components on the outer tread surface OUT is 1.03-1.3, and, a proportion of a negative ratio of the outer side surface OUT to a negative ratio of the inner side surface IN is 0.85-1.0.

Studless tire

A pneumatic tire exhibiting high traction performance. A center circumferential groove () is provided on the equator (CL) of the tread (), and between shoulder circumferential grooves () on both sides of the center circumferential groove () are arranged first lateral grooves () formed at a smaller angle relative to the axial direction of the tire than the first lateral groove (). One end of each first lateral groove () and one end of each second lateral groove () are made to merge at a shoulder circumferential groove (), and shoulder lateral grooves () are arranged on the outer side of each shoulder circumferential groove (). Each shoulder lateral groove () extends from the merging portion toward a tread end (E) and is formed at a smaller angle relative to the axial direction of the tire than that of the first lateral groove (). Because the angle of the shoulder lateral grooves () relative to the axial direction of the tire is less, traction performance of the tire increases.

A pneumatic tire according to the present invention includes blocks on its tread which are segmented by plural circumferential groovesextending along a tire circumferential direction and plural lateral groovesextending along a tread width direction. Circumferential sipes extending along the tire circumferential direction are provided in the blocks. Inside circumferential sipes extend straight along a tire radial direction and outside circumferential sipes extend along the tire radial direction in zigzag patterns. According to the present invention, a handling performance, especially, a cornering performance can be improved regardless of road surface conditions.

Pneumatic tire with tread having inside and outside circumferential sipes

A plurality of shallow grooves which are shallower than a sipe are formed on land sections formed on treads of a pneumatic tire. The shallow grooves are configured so that a total sectional area of the shallow grooves per unit area in a cross section in a tire width direction in at least one of tread end areas arranged at end sides of the tread surface in the tire width direction or land end areas arranged at portions adjacent to a drain main groove on the land sections becomes larger than a total sectional area of the shallow grooves per unit on the other areas.

Growing community of inventors

Nakano-ku, Japan

Ryoichi Watabe