Sumitomo Rubber Industries Limited

Hiroshi Kikuchi

Hiroki Uno

Takuya Osawa

Jo Shimizu

Tomohisa Kuriyama

Masahiro Nagase

Eisuke Hirosue

Kentaro Yagyu

Hiroaki Koga

Shota Makino

In a tire, a tread includes a cap layer forming a part of an outer surface of the tire, a base layer disposed inwardly of the cap layer in a radial direction, and an intermediate layer disposed between the cap layer and the base layer in the radial direction. A loss tangent of the intermediate layer at 30&#xb0; C. is less than a loss tangent of the cap layer at 30&#xb0; C. and a loss tangent of the base layer at 30&#xb0; C. is less than the loss tangent of the intermediate layer at 30&#xb0; C. The tread includes at least two three-layer body portions formed of the cap layer, the intermediate layer, and the base layer, and at least one two-layer body portion that is formed of the cap layer and the base layer and disposed between a first three-layer body portion and a second three-layer body portion.

Tire

In a tire, a tread includes a cap layer forming a part of the outer surface of the tire, an intermediate layer disposed inwardly of the cap layer in the radial direction, and a base layer disposed inwardly of the intermediate layer in the radial direction. A loss tangent of the intermediate layer at 30&#xb0; C. is less than a loss tangent of the cap layer at 30&#xb0; C., and a loss tangent of the base layer at 30&#xb0; C. is less than the loss tangent of the intermediate layer at 30&#xb0; C. An outer end of the cap layer is disposed outwardly of an outer end of the base layer in the axial direction. In the radial direction, a position of the outer end of the cap layer coincides with a position of the outer end of the base layer, or the outer end of the cap layer is disposed inwardly of the outer end of the base layer.

A tireincludes a tread, a pair of sidewalls, a pair of beads, a carcass, a belt, an inner liner, and a pair of insertion layersdisposed between the carcassand the inner liner. Each insertion layeris disposed between an end of the beltand an end PB of the bead. Each insertion layerhas a volume resistivity of less than 10&#x3a9;&#xb7;cm. A complex elastic modulus of the insertion layeris equivalent to or higher than a complex elastic modulus of the inner liner. A thickness of each sidewallat a maximum width position PW is not greater than 5.0 mm.

A tire includes a tread portion including at least one land portion having axially spaced first and second ends. The at least one land portion is provided with lateral grooves extending from the first end to terminal ends terminating within the at least one land portion, first sipes each extending along a tire circumferential direction to connect a pair of lateral grooves arranged adjacently in the tire circumferential direction, second sipes extending from the first end toward the first sipes, and third sipes extending from the second end toward the first sipes. The second sipes and the third sipes are arranged without intersecting the lateral grooves.

A tire includes a tread portion being provided with a pair of circumferentially and continuously extending shoulder main grooves and at least one crown main groove between the shoulder main grooves to form a pair of middle portions each of which is between adjacent one crown main groove and one shoulder main groove. Each of the middle portions is provided with a circumferentially and continuously extending longitudinal sipe, a plurality of inner middle sipes extending axially outwardly from the crown main groove and terminating without reaching the longitudinal sipe and a plurality of outer middle sipe extending axially inwardly from the shoulder main groove and terminating without reaching the longitudinal sipe. The number of the outer middle sipes is greater than the number of the inner middle sipes.

Growing community of inventors

Kobe, Japan

Hiroshi Kikuchi