Sumitomo Rubber Industries Limited

Sumitomo Rubber Company

Yoshiyuki Takada

Atsushi Yamahira

Mitsuharu Koya

Minoru Nishi

Kenji Takehara

Satoshi Tanaka

Satoko Tsujibayashi

Yoshiki Kanaya

Shigeki Yoshioka

Hidekatsu Nakatsuji

Takako Kitamura

Takehiko Kinoshita

Naoki Asakawa

Keiji Yasufuku

A heavy duty pneumatic tire in which occurrence of uneven wear is inhibited is provided. In the tire, each shoulder land portion includes a groove wall portion forming a wall of a shoulder circumferential groove, and a cap portion located outward of the groove wall portion in an axial direction. A wear resistance index of the groove wall portion is lower than a wear resistance index of the cap portion. A ratio of a distance in the axial direction from an outer edge of the shoulder circumferential groove to a boundary between the groove wall portion and the cap portion on an outer surface of the shoulder land portion, to a width in the axial direction of the shoulder land portion, is not less than 20% and not greater than 30%.

Heavy duty pneumatic tire

A heavy-duty pneumatic tire includes a section width being equal to or less than 335 mm, an aspect ratio being equal to or less than 55%, and a toroidal carcass extending between axially spaced bead portions through a tread portion and sidewall portions. The carcass includes a carcass ply which includes a main portion and a turn-up portion turned up around a bead core of each bead portion. A belt layer is disposed radially outward of the carcass in the tread portion, wherein a radially outer end of the turn-up portion is located between the main portion and the belt layer in the tread portion. A sheeted rubber layer is disposed between the main portion and the turn-up portions in each sidewall portion.

Heavy-duty pneumatic tire

A pneumatic tire to be mounted on a 15-degree-taper rim comprises a pair of bead portions each with a bead core, wherein in a meridian section of the tire under a state that the tire is not mounted on the rim but the bead portions are held such that the bead width is equal to the rim width of the 15-degree-taper rim, the bead base surface of each bead portion, which is defined as extending between a bead heel and a bead toe, is substantially straight and inclined at an angle of from 22 to 26 degrees with respect to the tire axial direction, and a ratio La/Lb of the axial width La of the bead base surface to the maximum width Lb of the bead core is in a range of from 1.3 to 1.6.

Pneumatic tire with specified bead base surface

A pneumatic tire comprises a tread portion provided with blocks, each block provided with circumferentially opening V-shaped corners each defined between two corner walls intersecting each other. In a cross section including the intersecting line K of the two corner walls and a normal line drawn normally to the tread face from a radially outer end of the intersecting line K, the intersecting line K comprising an upper slanting part KU and a lower normal part KL, the upper slanting part KU extending radially inwards from the tread face to a point P with an inclination angle &thgr; with respect to said normal line, and the lower normal part KL extending radially inwardly from the point P in substantially parallel to the normal line. The depth D of the point P from the tread face being in a range of from 0.30 to 0.50 times the height H of the block.

Pneumatic tire including blocks with V-shaped corners

Tire for automobile

A heavy duty tire is provided in the tread portion with a circumferentially extending main groove on each side of the tire equator, a circumferentially extending narrow groove on each side of each main groove, lug grooves extending from the tread edges to the axially inner narrow grooves, and slits extending between the inner narrow grooves so as to form a rib-like portion between the two inner narrow grooves, first blocks between the inner narrow groove and main groove, second blocks between the main groove and axially outer narrow groove, and third blocks between the outer narrow groove and tread edge; the main grooves are disposed at a distance of 15 to 25% of the tread width from the tire equator; the main groove depth is 10 to 12% of the tread width; the narrow groove depth is less than the main groove depth; and the slit depth is 0.2 to 0.3 time the main groove depth.

Heavy duty tire including wide main grooves, narrow grooves and lug grooves

A pneumatic tire having a block type tread pattern improved in stone trapping, which comprises a tread portion being provided with a mesh of grooves to define a plurality of blocks consisting of shoulder blocks adjacent to the tread edges and central blocks other than the shoulder blocks, each of the central blocks being surrounded by at least one projection standing out from the groove bottom leaving spaces from the groove walls, the projection comprising alternate wide main portions and narrow coupler portions, the height of the wide main portions being 10 to 25% of the groove depth, the height of the narrow coupler portions being 5 to 10% of the groove depth, the length of each of the wide main portions being 3 to 10 mm, the length of each of the narrow coupler portions being 2 to 8 mm, the width of the narrow coupler portions being 0.5 to 2 mm, and the main portions comprises first main portions and second main portions, the first main portions being disposed between junctions of the grooves and being relatively taller than said second main portions.

Pneumatic tire

A heavy duty radial tire is provided between the tread edge and the maximum tire width point with a profile which is formed by adding at least a protrusion to a basic profile, the basic profile consisting of an upper line and a lower line, the upper line extending radially inwardly from the tread edge and curved concavely so as to have a center of curvature outside the tire, the lower line extending radially outwardly from the maximum tire width point and curved convexly so as to have a center of curvature inside the tire, the upper line and lower line intersecting each other so as to form an inflection point, the radial height of the inflection point from the bead base line being in the range of from 0.82 to 0.88 times a groove bottom line height, the groove bottom line height being the radial height between the bead base line and a groove bottom line drawn parallel with the tread surface at the depth of the main grooves measured at axial ends of the groove bottom line, and the protrusion having an apex positioned such that the axial distance measured axially outwardly from the inflection point to the apex is in the range of from 4 to 8 mm, and the radial distance measured between the inflection point and the apex is in the range of from 0 to 5 mm, whereby the resistance to carcass damage can be improved if the carcass is minimized.

Heavy-duty radial tire with specified upper side wall profile

A heavy duty pneumatic tire comprises a pair of bead portions with a bead toe, a bead core disposed in each bead portion, a carcass comprising at least one ply of cords extending between the bead portions and turned up around the bead cores, an inner liner made of an airtight rubber compound disposed inside the carcass along the inner surface of the tire, the inner liner extending from one of the bead portion to the other and terminating before the bead toe, a chafer made of a hard rubber compound disposed in each bead portion along the bead base, the chafer extending axially inwardly to the bead toe, and an adhesiveness improvement rubber layer disposed between inner liner and chafer.

Heavy duty pneumatic tire with an adhesive rubber layer between the

Automobile tire

A pneumatic tire having a block type tread pattern improved in stone trapping, which comprises the tread portion provided with a mesh of grooves to define blocks, each block surrounded by at least one projection standing out from the groove bottom leaving spaces from the groove walls, the projection comprising alternate wide main portions and narrow coupler portions, the height of the wide main portions being in the range of from 10 to 25% of the groove depth, the height of the narrow coupler portions being not less than 5% but less than 10% of the groove depth, the length of each of the wide main portions being in the range of from 3 mm to 10 mm, the length of each of the narrow coupler portions being in the range of from 2 mm to 5 mm, and the width of the narrow coupler portions being in the range of from 1 mm to 2 mm.

Pneumatic tire including at least one projection

A heavy duty tire having an improved tread wear resistance, which comprises a tread portion provided on each side of the tire equator with a wide circumferential groove and a narrow circumferential groove. The wide circumferential groove is spaced apart from the tire equator by an axial distance of 15 to 25% of the tread width. The narrow circumferential groove is disposed on the axially inside of the wide circumferential groove and spaced apart from the axially inner groove edge of the wide circumferential groove by an axial distance of 0.02 to 0.05 times the tread width. The depth of the wide circumferential groove is in the range of 0.05 to 0.08 times the tread width. The depth of the narrow circumferential groove is in the range of 0.7 to 1.0 times the depth of the wide circumferential groove. The groove width of the narrow circumferential groove is in the range of 1.5 to 2.5 mm.

Heavy duty tire including narrow circumferential grooves

A pneumatic tire for heavy vehicle comprises first platforms bent at bent sections of a main groove extending zigzag in a circumferential direction of the tire, a second platform linearly extending between one of the first platforms and another of the first platforms, and a third platform extending between the one of the first platforms and the second platform, wherein the first, second, and third platforms are arranged at a bottom of the main groove within half a pitch of the main groove, a length of the first platform in the circumferential direction of the tire, a length of the second platform in the circumferential direction of the tire, and a length from one end of the one of the first platforms to one end of the another of the first platforms are different from each other; a length of the one of the first platforms is larger than the length of the second platform, and a width of each of the first and second platforms in an axial direction orthogonal to the circumferential direction of the tire and a height from the bottom of the main groove of each of the first and second platforms are set to be larger than a width of the third platform in the axial direction orthogonal to the circumferential direction of the tire and a height of the third platform from the bottom of the main groove, respectively.

Growing community of inventors

Kobe, Japan

Yoshiyuki Takada