Sumitomo Rubber Industries Limited

Chieko Aoki

Naoki Yukawa

Hideaki Sugihara

Masami Nishikawa

Tokuzo Nakajima

Kazuo Asano

Naoaki Iwasaki

Tadao Matsumoto

Takaaki Ishida

Toru Fukumoto

Kiichiro Kakumu

Hiroshi Matsui

A pneumatic tireincludes a pair of beadsand a carcassextending on and between both beads. Each beadincludes a core. The coreincludes: a main bodyincluding a cordextending in a circumferential direction; and a stretchable portionformed from a crosslinked rubber. The stretchable portionis located inward of the main bodyin an axial direction. The stretchable portionhas a size with which at least one cross-section of the cordcan be included therein in a cross-section of the bead. Preferably, in the tire, the main bodyincludes a hard unit and a soft unit. The soft unit is located outward of the hard unit in a radial direction. A hard cord of the hard unit stretches more easily than a soft cord of the soft unit.

Pneumatic tire having bead core with stretchable portion

A pneumatic tire has bead cores provided in bead portions. The bead cores include a first bead wire, and a second bead wire having an elongation &#x3b1;, where &#x3b1;(%)=&#x394;L/L&#xd7;100, L is a length of each of the bead wires under no load, and &#x394;L is an elongation amount obtained when a unit load is applied. The elongation &#x3b1; of the second bead wire is greater than an elongation of the first bead wire. The number of the second bead wire provided in an innermost side portion in a tire radial direction is at least one.

Pneumatic tire

A run-flat tire capable of reducing weight and enhancing its uniformity. The run-flat tireprovides a toroidal carcassextending from a tread portionto the bead core of each bead portionthrough each of sidewall portionsand a pair of side reinforcing rubbersarranged inside the carcassand extending along the sidewall portionsin the tire radial direction inwardly and outwardly. In the outer surface of the tread portion, pattern elements are arranged, thereby forming a pitch pattern. Each of the side reinforcing rubberprovides with recessescircumferentially spaced on the inner surface of side reinforcing rubber facing the tire cavity. The total number (n) of recesseson each of the side reinforcing rubberis 0.70 to 1.30 times the total number of pattern elements.

Run-flat tire

A tire noise damper to be disposed in an annular tire hollow formed between a wheel rim an a pneumatic tire mounted thereon, the damper made of a flexible material and comprising a base to be secured to the wheel rim and at least one flap extending from the base to be risen radially outwards from the wheel rim by centrifugal force during running to block the annular tire hollow. For example, the damper comprises at least one annular elastic band to be put around the wheel rim, the annular band provided with at least one U-cut for forming a flap, and the base is formed by the remaining annular portion of the band. In another example, the damper is made of a strip of the fixable material having a certain length, the base is formed by one end portion of the strip, and the flap is formed by the remaining portion of the strip.

Noise damper for pneumatic tire

A tire noise reducing system includes a pneumatic tire, a wheel rim and a noise damper disposed in a cavity formed between the rim and tire the noise damper is made of a porous material having a specific gravity of from 0.005 to 0.06 and secured on a surface facing the cavity, the volume S2 of the noise damper is in a range of from 0.4 to 20.0% of the volume S1 of the cavity. Preferably, the noise damper is provided with an uneven surface or an outer layer for less sound reflection, and the shape index E of the noise damper is more than 1, and the ratio T/W of the thickness T to the width W of the damper is not less than 1.

Tire noise reducing system

A tire noise reducing system comprises a wheel rim, a pneumatic tire to be mounted on the wheel rim and a noise damper to be disposed in an annular tire cavity enclosed by the wheel rim and the pneumatic tire mounted thereon, wherein the noise damper is made of a multi-cellular material whose volume S2 is in a range of not less than 0.4% of the volume S1 of said annular tire cavity. Preferably, the specific gravity of the damper is set in a range of from 0.005 to 0.06.

A tire noise reducing system comprises a pneumatic tire, a wheel rim and a noise damper disposed in a cavity formed between the rim and tire when mounted as being surrounded by the tire and rim, the noise damper is made of a porous material having a specific gravity of from 0.005 to 0.06 and secured on a surface facing the cavity, the volume S of the noise damper is in a range of from 0.4 to 20.0% of the volume S of the cavity. Preferably, the noise damper is provided with an uneven surface or an outer layer for less sound reflection, and the shape index E of the noise damper is more than 1, and the ratio T/W of the thickness T to the width W of the damper is not less than 1.

A tire noise reducing system includes a wheel rim, a pneumatic tire mounted on the wheel rim to form an annular tire hollow, and a resonance damper disposed in the annular tire hollow, wherein the damper is one of an annular elastic loose band disposed around the rim and a flexible slack strip having a certain length and fixed to the wheel rim at two points so that a portion between the fixed points slacks, whereby a loose portion of the loose band and the slack portion of the slack strip are risen by a centrifugal force during running to at least partially block the annular tire hollow.

A vehicle tire which has an aspect ratio of less than about 55% and comprises a tread portion having a profile whose radius of curvature decreases substantially continuously from the tire equator to each tread edges. The tread profile from the tire equator to each tread edge is substantially defined by a curve such as ellipse, cycloid, epicycloid, involute curves and the like, of which equation is differentiable in the range between the tire equator and each tread edge.

Vehicle tire including tread portion defined by cycloid curve or epicycloid curve

A tire noise damper to be disposed in an annular tire cavity formed between a wheel rim and a pneumatic tire mounted thereon. The damper comprises an annular band-like body which is made of an elastomeric material and provided with at least one generally U-shaped cut oriented in a circumferential direction. The cutout formed by the at least one U-shaped cut forms a flap risen by a centrifugal force during running, and the remainder forms a base band to be put around a bottom of the wheel rim in an elongated condition. In order to reduce resonance of the air in the tire cavity in not only the fundamental mode but also the higher harmonic modes, the flap may have a relatively long length such that, when risen, a radially outer end portion thereof comes into contact with the radially inside of a tread portion of the tire. Further, the flap may be made of nonwoven fabric at least partially.

A tire noise damper to be disposed in an annular tire hollow formed between a wheel rim and a pneumatic tire mounted thereon, the damper made of a flexible material and comprising a base to be secured to the wheel rim and at least one flap extending from the base to be risen radially outwards from the wheel rim by centrifugal force during running to block the annular tire hollow. For example, the damper comprises at least one annular elastic band to be put around the wheel rim, the annular band provided with at least one U-cut for forming a flap, and the base is formed by the remaining annular portion of the band. In another example, the damper is made of a strip of the fixable material having a certain length, the base is formed by one end portion of the strip, and the flap is formed by the remaining portion of the strip.

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Kobe, Japan

Chieko Aoki