Bridgestone Corporation

Kazunori Shinohara

Yasuo Himuro

Naoya Ochi

Nobuyuki Okamura

Yuji Tateo

Kojiro Yamaguchi

Koji Yamauchi

Toshiaki Kobayashi

Misao Kawabata

Hisao Ushikubo

Shinichi Abe

Katsuhiko Kinoshita

Toru Fukuoka

Toshihiro Sadohara

Yukio Yamakawa

A pneumatic tire capable of obtaining a high tire performance on ice without decreasing the other performances can be provided. A plurality of narrow grooves each having a rectangular cross section are formed on one sipe side wall surface of a sipe in an inclined manner at a certain angle. Even when the sipe is closed under a load application to the tire, portions having the narrow grooves are not brought into contact with the other sipe side wall surface of the sipe so that water on an ice road surface can be absorbed and removed by the narrow grooves. Further, in the case of the narrow groove in which one end is opened to a road contact surface portion and the other end is opened to a side surface, the absorbed water can be continuously discharged to an outside of a block in serial order so that the water on the ice road surface can be further removed. Since the water removal can be performed without a great number of sipes, a decrease of a block rigidity due to employing a great number of sipes does not occur.

Pneumatic tire

A pneumatic tire in which a foamed rubber layer having closed cells is provided at a surface of a tire tread which substantially contacts at least a road surface, wherein the foamed rubber layer has closed cells whose average diameter is about 1 .mu.m to about 120 .mu.m and has an expansion ratio of about 1% to about 100%, a solid-phase rubber portion of the foamed rubber layer has a rubber composition in which at least both of a diene-type rubber and silica are mixed, and an amount of the silica is about 10 to about 80 parts by weight based on 100 parts by weight of the diene-type rubber. The pneumatic tire exhibits excellent traction and braking abilities and controllability on snowy, icy and wet road surfaces.

Pneumatic tire having foamed rubber

A pneumatic studless tire comprises a tread provided with a plurality of circumferential grooves, a plurality of lateral grooves and many blocks defined by these circumferential grooves and lateral grooves, in which (1) a plurality of wave-shaped sipes are formed in each of the blocks so as to make them dense at central region of the block in the widthwise direction of the tire and sparse at both side regions thereof, and (2) an amplitude of the wave-shaped sipe in each side region of the block is smaller than that in the central region of the block.

Pneumatic studless tires including wave-shaped sipes

A pneumatic tire in which a foamed rubber layer having closed cells is provided at a surface of a tire tread which substantially contacts at least a road surface, wherein the foamed rubber layer has closed cells whose average diameter is about 1 m to about 120 m and has an expansion ratio of about 1% to about 100%, a solid-phase rubber portion of the foamed rubber layer has a rubber composition in which at least both of a diene-type rubber and silica are mixed, and an amount of the silica is about 10 to about 80 parts by weight based on 100 parts by weight of the diene-type rubber. The pneumatic tire exhibits excellent traction and braking abilities and controllability on snowy, icy and wet road surfaces.

Automobile tire

Growing community of inventors

Tokyo, Japan

Kazunori Shinohara