The Yokohama Rubber Co., Ltd.

Kogakuin University

Kotobuki Seating Company, Ltd.

Toshihiko Suzuki

Izumi Kuramochi

Hiroshi Tokizaki

Sadakazu Takei

Kenichi Shirai

Tetsuya Kuze

Masahiro Ishida

Yoshimasa Hashimoto

Hisaya Morishita

Daizou Etou

Noriaki Aida

Masatoshi Kuwajima

Hirohisa Hazama

Kohtaroh Iwabuchi

Eiichi Iida

Takashi Yamashita

Junichi Ohtani

Masatoshi Kuwazima

Hiroya Takenaka

Teruhiko Kikuchi

Capsule bed

Automobile tire

Pitch arrangement evaluation system of tread pattern of pneumatic tire

A pneumatic radial tire has a tread pattern having a pair of straight main grooves each having a width equal to 8-13 percent of a ground contact width W of the tire and extending in parallel on opposite sides of an equator of the tire, a plurality of lug grooves extending across shoulder regions formed on the outersides of the pair of main grooves from the pair of main grooves outwardly toward the ends of the ground contact surface of the tire to form in cooperation with the main grooves successive rows of blocks, and a plurality of V-shaped sub-grooves in the shoulder regions spaced at a predetermined pitch apart in the circumferential direction of the tire and extending divergently with respect to the direction of reverse rotation of the tire, wherein the ratio of a distance W1 between respective centers of the main grooves to the ground contact width W is in the range of 0.2.ltoreq.W1/W.ltoreq.0.4; an angle .alpha. of inclination of the lug grooves with respect to the circumferential direction of the tire as viewed from the reverse tire rotating direction is in the range of 90.degree.-130.degree.; and an angle .beta. defined by the V-shaped sub-grooves is in the range of 15.degree.-35.degree..

Pneumatic radial tire

Two or three main grooves, which extend in the circumferential direction of a tire, are provided in the central ground contacting region alone of a tread surface of the tire the rotational direction of which is designated to one direction, and at least one rib extending in the circumferential direction of the tire is formed between the main grooves. A plurality of sub-grooves respectively extending from the both sides of the main grooves outward in the widthwise direction of the tire up to at least the ground contacting ends of the tire are arranged at a predetermined pitch in the circumferential direction of the tire in such a manner that the sub-grooves formed in zigzag lines are inclined with the inner end portions thereof positioned on the forward side with respect to the rotational direction of the tire. The sub-grooves do not communicate with the main grooves but communicate with land portions separated by the sub-grooves. This enables pattern noise to be reduced without spoiling the drainage performance.

Pneumatic tire including zig-zag subgrooves

Pneumatic radial tire including main grooves and sub-grooves

A pneumatic tire in which sub-grooves extending at least in the widthwise direction of the tire are provided in a center portion of a tread surface and shoulder portions thereof on both sides of the center portion at a predetermined pitch, both the width and depth of the sub-grooves in the two shoulder portions being set larger than those of the sub-grooves in the center portion, a ratio of the area of the sub-grooves in the two shoulder portions to that of the tread surface being set larger than a ratio of the area of the sub-grooves in the center portion to that of the tread surface. This tire can be used with the air pressure therein set higher under the on-road travelling condition, and lower under the off-road travelling condition.

Pneumatic tire having V-shaped subgrooves

Growing community of inventors

Hiratsuka, Japan

Toshihiko Suzuki