Sumitomo Rubber Industries Limited

Taro Okabe

Satoshi Tanaka

Minoru Nishi

Yasushi Shinmura

Makoto Igarashi

Ikuo Atake

Yukihide Oya

A tireincludes: a pair of beads; a carcass plyhaving a ply main bodyand turned-up portions; and a pair of fillersthat are located outward of the turned-up portionsin the axial direction and that include metal cords. In a radial direction, a first endof each filleris located inward of a bead base line, and a second endof each filleris located between an endof the turned-up portionand the bead base line. A recessis provided on a zone of each side surfaceof the tirebetween a maximum width position and the endof the turned-up portion

Heavy duty pneumatic tire

A heavy duty pneumatic tire includes a pair of beads, a carcass and a pair of bead fillers laminated outward with respect to the beads in the axial direction, respectively. Each bead includes a core and an apex, the carcass includes a carcass ply folded back around the core and having a main portion and a folding-back portion, each bead filler has an outer edge, an inner edge and a fitting portion to fit to a rim, the fitting portion includes a bottom surface to make contact with a seat surface of the rim and an outer-side contact surface to make contact with a flange of the rim, and the outer-side contact surface has inner-side, outer-side and middle portions such that when not mounted to the rim, the middle portion is recessed inward with respect to imaginary straight line Lpassing through outer edges of the inner-side and outer-side portions.

A heavy duty pneumatic tire includes a tread portion provided with circumferentially extending zigzag shaped main grooves, a plurality of land portions separated by the main grooves, and a plurality of lateral grooves to form a plurality of block elements on each land portion. Each land portion comprises a number of pitches in a range of from 40 to 50, wherein each pitch consists of one block element and one lateral groove adjacent to the concerned block element. Each block element has a length in a range of from 85% to 95% of a length of the pitch. The main grooves include a crown main groove, a shoulder main groove, and a middle main groove. The middle main groove has a zigzag amplitude larger than those of the crown main groove and the shoulder main groove.

A heavy duty pneumatic tire includes a tread portion provided with at least three circumferential main grooves, and a plurality of lateral grooves extending between adjacent main grooves or between one main groove and a tread edge, to form at least one block row comprising a plurality of blocks. The block row comprises a plurality of pitch elements each of which consists of circumferentially adjacent one lateral groove and one block. The tread portion has a land ratio in a range of from 70% to 80%. The block row comprises a number of pitch elements in a range of from 40 to 50, and each lateral groove has a groove width in a range of from 5% to 15% in relation to a circumferential length of the block in each pitch element.

A heavy duty pneumatic tire includes a tread portion provided with at least one circumferentially and continuously extending main groove, and a plurality of lateral grooves to form circumferentially repeated pitch elements each of which consists of one lateral groove and a block element divided between two adjacent lateral grooves. The tread portion has a land ratio in a range of from 70% to 80%, and the pitch elements in a range of from 40 to 50. Each lateral groove has a circumferential groove width in a range of from 5% to 15% in relation to a circumferential length of the pitch element, and an angle in a range of from 45 to 85 degrees with respect to a circumferential direction of the tire.

A heavy duty pneumatic tire has a belt and a tread such that ratio of width of the belt to width of the tread is greater than or equal to 0.95 and is not greater than 1.0. The tread has shoulder land portions on outer sides in axial direction, each shoulder portion has a cap layer including a body portion and a pad, the pad has complex elastic modulus greater than complex elastic modulus of the body portion, the body portion has loss tangent less than loss tangent of the pad, and each shoulder portion has ground-contact surface which has outer and inner ground-contact surfaces separated by boundary between the body portion and pad such that ratio of average ground-contact pressure of the outer ground-contact surface relative to average ground-contact pressure of the inner ground contact surface is greater than or equal to 0.85 and is not greater than 0.95.

A heavy duty pneumatic tire includes a tread portion provided with a pair of shoulder main grooves disposed axially outermost side, and at a center main groove between the shoulder main grooves to form a pair of middle portions. Each middle portion is provided with a middle sub groove, axially outer middle lateral grooves, and inner middle lateral grooves. The respective number of outer and inner middle lateral grooves are of from 40 to 50 in each middle portion. Each of the outer and inner middle lateral grooves includes a shallow bottom part having a depth smaller than that of the shoulder and center main grooves. The shallow bottom part is provided with a groove bottom sipe that extends along a longitudinal direction of each lateral grooves and includes a first portion, and a second portion having a depth smaller than the first portion.

A heavy duty tire comprises a tread portion provided with belt plies and circumferentially-extending main grooves, wherein a shoulder rib area between the axially outermost shoulder main groove and a tread edge is subdivided by a sub groove into an axially inner main rib zone and an axially outer sub rib zone. The main rib zone is provided with a high elastic modulus rubber layer extending along the axially outer edge of the main rib zone to form a part of the tread face and made of rubber having an elastic-modulus higher than that of rubber forming the tread face except for said part of the tread face. The axial width (W) of the high elastic modulus rubber layer is 0.3 to 0.6 times the axial width (W) of the main rib zone.

Growing community of inventors

Kobe, Japan

Taro Okabe