Sumitomo Rubber Industries Limited

Ikuo Atake

Satoshi Tanaka

Masahiro Kishida

Taro Okabe

Shuji Kagimoto

Yoshiki Kanaya

Hana Sato

A heavy-duty tire includes a tread part formed such that the tread part includes a crown profile including tire equator, and a pair of shoulder profiles extending from outer sides of the crown profile to tread edges. In a tire cross section including tire rotation axis in 5% internal pressure state in which the tire is mounted to a normal rim, filled with air at internal pressure of 5% of normal internal pressure and loaded with no load, each of the crown and shoulder profiles has an arc shape convex toward tire radial direction outer side such that ratio Rc/Rs of curvature radius Re of the crown profile to curvature radius Rs of each shoulder profile is 7.0 or more, and a tire axial direction distance from the equator to a connecting point between the crown profile and each shoulder profile is 0.70 or more times a tread half width.

Heavy-duty tire

A tireincludes a plurality of ribsaligned in an axial direction. A rib, among the plurality of ribs, disposed on an outer side in the axial direction is sectioned into a body portionand a side portionby a groovethat extends in a circumferential direction. The tireincludes a treadand a pair of sidewalls. The sidewallsextend almost inward from ends, respectively, of the treadin a radial direction. The treadincludes a base layer, and a cap layerdisposed outward of the base layerin the radial direction. The side portionis formed by the cap layerand a corresponding one of the sidewalls. The sidewallis stacked on the cap layerin the side portion

Pneumatic tire

Shoulder drop wear and triangular wear are prevented. A heavy duty tire which includes a shoulder block includes a first arc portion having a radius of curvature, in which a tread contour includes an arc center at a tire equatorial surface at a 5% internal pressure state; and a second arc portion having a radius of curvature of which intersects with the first arc portion at an intersection. An arc center of the second arc portion is located on a radial line passing through the intersection. A ratio of the radii of curvature is between 0.2 and 0.5. A ratio between a tire radial direction distance from an equatorial point to a tread edge and a radial direction distance from the equatorial point to a virtual tread edge on a line extending from the first arc portion is equal to or higher than 0.5 or lower than 1.0.

Heavy duty tire

A heavy duty pneumatic tire comprises a tread portion provided with a crown main groove and a middle axial groove. The middle axial groove extends axially outwardly from its axially inner end axially outwardly spaced apart from the crown main groove and inclines with respect to the tire circumferential direction at an angle of from 45 to 75 degrees. In a cross section along the widthwise center line of the middle axial groove, an end wall of the axially inner end is inclined at an angle 0 to 50 degrees with respect to the normal direction to the tread from the radially outer edge of the end wall toward the groove bottom, and a corner between the end wall and the groove bottom is chamfered by an arc having a radius of curvature of 1 to 10 mm.

Heavy duty pneumatic tire

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 pneumatic tire comprises a tread portion provided with a plurality of blocks, each of the block having a block wall surface facing a transverse groove inclined at an angle (theta) of from 5 to 40 degrees with respect to the tire axial-direction so as to define an acute-angled corner and an obtuse-angled corner on the block. The block wall surface between the acute-angled corner and the obtuse-angled corner is provided with at least two slits having a width of from 0.3 to 2.0 mm. A distance Pmeasured from the acute-angled corner to one of the at least two slits which is nearest to the acute-angled corner is more than a distance Pmeasured from said obtuse-angled corner to one of said at least two slits which is nearest to the obtuse-angled corner; each distance is measured along the radially outer edge of the block wall surface to the widthwise center of the slit.

Growing community of inventors

Kobe, Japan

Ikuo Atake