Sumitomo Rubber Industries Limited

Kenji Hatakenaka

Akihiro Miyoshi

Kenichi Mineta

Hidehiko Hino

Toru Kawai

Keiji Shimizu

A pneumatic tire comprises: a tread rubber having a Shore A hardness of not more than 65 degrees at 20 degrees C.; a tread portion provided with at least one circumferential row of blocks having circumferential edges adjacent to lateral grooves; each of the circumferential edges having a mean inclination angle of 0 to 60 degrees with respect to the tire axial direction; sidewalls of the lateral grooves on one side in the tire circumferential direction each comprising a first upper slope extending from the top of the adjacent block to a first point at a depth h1, while inclining at an angle .alpha.1, and a first lower slope extending from said first point towards the groove bottom, while inclining at an angle .alpha.2 smaller than the angle .alpha.1,; the remaining sidewalls of the lateral grooves on the other side each comprising a second upper slope extending from the top of the adjacent block to a second point at a different depth h2 than said depth h1, while inclining at an angle .beta.1, and a second lower slope extending straight from the second point towards the groove bottom, while inclining at an angle .beta.2 smaller than the angle .beta.1; and the lateral grooves comprising a portion (A) in which the depth h1 is more than the depth h2 but not more than 0.8 times the lateral groove depth, and a portion (B) in which the depth h2 is more than the depth h1 but not more than 0.8 times the lateral groove depth.

Studless tire having lateral grooves

A studless tire with a tread pattern comprising blocks that are defined by longitudinal and transverse grooves and having at least one row of blocks that extends in the peripheral direction of the tire. The peripheral rows of blocks are such that at least one sub-block is provided within one pitch of the tread pattern outside an adjacent block in the tire's rotating axle. And the sub-block is separated from the block by a sub-groove less deep than the longitudinal and transverse grooves and has the longer side in the peripheral direction and the shorter side in the direction of the rotating axle.

Studless tire

Automobile tire

Growing community of inventors

Hyogo, Japan

Kenji Hatakenaka