Bridgestone Corporation

Takashi Kukimoto

Hiroyuki Koseki

Yasutoshi Aoki

Naoto Yamagishi

Shinji Usui

Yasuhiko Kobayashi

Yoshinobu Shoyama

Takehiro Tsukamoto

Automobile tire

An uneven wear-resisting heavy duty pneumatic tire comprises main grooves continuously extending in a tread of the tire along a circumference thereof, land portions separated by the main grooves, and stepped zones each provided in the land. Each stepped zone has a surface located radially inside of the tread by a step a viewed sectionally. Each of said stepped zones is separated from the adajcent land portions via a pair of circumferentially extending grooves or narrow cuts. An uneven wearing-sacrificing portion is formed by the surface of the stepped zone. The uneven wear-sacrificed portion slide-contacts with the tread within the tread ground-contacting area for supporting the load exerted upon the tire.

Heavy duty pneumatic tires preventing uneven wearing

An uneven wear-resisting heavy duty pneumatic tire comprises main grooves continuously extending in a tread of the tire along a circumference thereof, land portions separated by the main grooves, and stepped zones each provided in the land. Each stepped zone has a surface located radially inside of the tread by a step a viewed sectionally. Each of said stepped zones is separated from the adjacent land portions via a pair of circumferentially extending grooves or narrow cuts. An uneven wearing-sacrificing portion is formed by the surface of the stepped zone. The unever wear-sacrificed portion slide-contacts with the tread within the tread ground-contacting area for supporting the load exerted upon the tire.

Heavy duty pneumatic tires including stepped tread zones for preventing

A pneumatic radial tire capable of preventing the occurrence of uneven wear due to lateral force produced in the cornering is provided with a recess formed in at least one-side tread shoulder opening toward the side face of the tire and continuously extending circumferentially of the shoulder and has particular ratios of tire thickness to sidewall thickness and distance between deepest position of recession and equator of tire to distance between ground contact end of tread and equator of tire.

Pneumatic radial tires including shoulder recesses

A low-section pneumatic radial tire having an aspect ratio of not more than 0.85 and excellent resistance to uneven wear and belt end separation comprises at least one carcass ply of radial construction, a tread and a belt of at least two belt plies. In this tire, the reinforcing layer composed of two or less reinforcing plies is arranged between an outermost belt ply in the radial direction and the carcass, and at least one reinforcing ply of the reinforcing layer is comprised of first and second reinforcing ply segments arranged at both sides with respect to the equator so that the ply segment is located between an outer point separated from a shoulder end at a distance corresponding to 1/7 of tread width and an inner point separated from the equator of the tire at a distance corresponding to 1/10 of tread width.

Low-section pneumatic radial tires

A pneumatic radial tire includes a carcass layer consisting of at least one carcass ply having cords embedded therein and extending substantially in radial directions, a tread arranged radially outwardly of the carcass layer, and a belt layer consisting of at least tow layers of belt plies having cords embedded therein intersecting with each other at angles within 10.degree.-40.degree.. The tire comprises a reinforcing layer arranged between the carcass layer and the belt ply arranged radially outermost and consisting of at most two layers of reinforcing plies having cords embedded therein substantially in parallel with an equatorial plane. Both outer ends of the reinforcing layer are positioned inwardly, in width directions, of locations spaced apart one fifth of a tread width of the tire from shoulder ends. Outer ends of at least one reinforcing ply are positioned inwardly, in the width directions, of outermost ends of main grooves in the tread between center ribs and side ribs. The side ribs are formed with a plurality of traverse grooves spaced apart from each other in circumferential directions and having both ends opening into the main grooves.

Pneumatic radial tire

A heavy duty pneumatic tire comprises a tread, two side walls, two beads, a radial carcass reinforcement, and a belt composed of at least two plies of which cords are intersected in the adjacent plies. The radius of curvature of the contour of the tread appearing in a tire cross section including a tire rotary axis is asymmetrical with respect to the tire equatorial plane. A larger radius of curvature is given to the tread portion to be located outside when the tire is mounted to a wheel, while a smaller radius of curvature is given to the tread portion to be located on the inner side when the tire is mounted to the wheel. The difference between the larger radius of curvature and the smaller radius of curvature is not less than 70 mm. The rigidity of the tread is larger on the tread portion having the larger radius of curvature than on the tread portion having the smaller radius of curvature.

Heavy duty pneumatic tire

A pneumatic radial tires having a tread of an asymmetrical profile are disclosed. A circumferential location at which a tread takes its maximum outer diameter is deviated from a tire equator outwardly opposite to a side on which the tire is to be mounted to a vehicle, by a distance L equal to a range from 0.05 to 0.30 times as long as a width W of the tread. A ratio of d.sub.2 /d.sub.1 is set at a range from 0.98 to 1.00 in which d.sub.1 and d.sub.2 are diameters of shoulders of the tread on the mounted tire outer side and mounted tire inner side, respectively. The tires are free from uneven wear such as shoulder drop uneven wear, river wear and one side wear.

Growing community of inventors

Kodaira, Japan

Takashi Kukimoto