Bridgestone Corporation

Ken Masaoka

Hiroyuki Matsumoto

Yuichiro Ogawa

Akiyoshi Shimizu

Hiroki Sawada

Mitsuo Hashimoto

The invention provides an assembly of a pneumatic tire and a rim. The tire has at least one carcass plyand a belt layer. The plyis composed of ply cords and has end portions. The belt layeris composed of belt cords provided outside of the ply. Each belt cord extends in a direction intersecting the ply cord. Each of the end portions is held in the rim. The width of the tire is maximum in a circumferential cross section 'T' with a cylindrical shape with respect to the center axis 'D' of the tire. The cross section &#x201c;T&#x201d; extends through the rim. When the tire is rolled under a load and a stress is applied on the tire as an arrow &#x201c;X&#x201d;, a neighboring portionnear the end portionsis considerably bending-deformed as arrows &#x201c;Y&#x201d; to absorb the stress. The roundness of the belt layeris thus preserved to reduce the rolling resistance of the tire considerably.

Assembly of a pneumatic tire and a rim, a pneumatic tire and a rim for a pneumatic tire

A pneumatic tire comprises a pair of bead portions, a pair of sidewall portion, a tread portion, a radial carcass of at least one ply, and a belt, wherein the tread portion is provided with two or more circumferential main grooves formed in a tread rubber at an inner region sandwiched by both shoulder regions and one or more circumferential ribs defined by two adjoining circumferential main grooves, and at least two circumferential fine grooves are formed in the circumferential rib.

Pneumatic tire including zig-zag circumferential fine grooves

A pneumatic tire comprising a tread portion having a plurality of blocks which are defined by inclined grooves and by a plurality of connection groves connecting with the inclined grooves or with the tread end, wherein the side wall portion of a block facing a first inclined groove coming into contact with the ground precedingly is more rigid than the side wall portion of the same block facing a second inclined groove coming into contact with the ground following the first inclined groove, and the side wall portion of the same block located at the inner side in the tire width direction is more rigid than the side wall portion located at the outer side in the tire width direction.

Pneumatic tire including inclined grooves and connection grooves

Pneumatic tire with grooves having bending or winding portion

The radius of curvature of the end portion of the block of a tire at the equatorial plane side of the tire is the same as the radius of the tire thereat. On the other hand, the radius of curvature of the end portion of the block at the shoulder side is smaller than the radius of the tire thereat, and the point which protrudes furthest is between the center and the trailing edge portion of the block 16. The shape of the radially outward surface of the block protrudes further toward the shoulder side end portion, which is an area in which the wear of the leading edge portion progresses furthest. The ground contact pressure at the shoulder side becomes even lower. Accordingly, the leading edge portion can smoothly slide against the road surface. As a result, the progress of the wear from the leading edge portion is promoted, and the effect of preventing the heel-and-toe wear becomes higher.

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Tokyo, Japan

Ken Masaoka