The Yokohama Rubber Co., Ltd.

Eiichi Iida

Shinya Harikae

Toshihiko Suzuki

Susumu Imamiya

Naoya Amino

Takayuki Toyoshima

Noboru Okada

Haruhisa Hasegawa

Motohide Takasugi

Ichiro Takasu

Tatsuya Takaoka

Hisayoshi Fukuzawa

Toshihiko Take

Hiroya Takenaka

In a pneumatic tire composed of a carcass layer crossing between a pair of left and right bead cores, the bead cores comprise a fastening bead core for fastening an end of the carcass layer to be turned up around the fastening bead core, and a non-fastening bead core free from the end of the carcass layer. An inner circumferential radius Rof the non-fastening bead core is set smaller than an inner circumferential radius Rof the end of the carcass layer to be turned up around the fastening bead core.

Pneumatic tire

A tire/wheel assembly, wherein bent parts () bent outward are formed at the leg end parts of an annular shell (), an inclination angle (&#x3b1;) of a line segment Lextending from the axially outer end (P) of the bent part () through the apex (P) of a hump () on a rim relative to a direction perpendicular to a tire axis is set to within &#xb1;5&#xb0; in a cross section orthogonal to the circumferential direction of the annular shell (), the area () of the annular shell equal to the height (B) of at least 35% of the height (A) from the radially inner end of the annular shell is formed linearly, the inclination angle (&#x3b1;) of an extension line (L) along the inner surface of the linear area () relative to the direction perpendicular to the tire axis is 15 to 30&#xb0; in axial inner side, and the extension line (L) passes between the apex (P) of the hump () and the toe tip (P) of a tire bead part.

Tire/wheel assembly

A tire forming system includes a band forming machine, a shaping forming machine, a belt/tread forming machine, means for supplying a band member and means for supplying a belt/tread member. The means for supplying the band member include an inner liner supply means, carcass supply means, band rubber parts supply means and bead supply means. The means for supplying the belt/tread member include belt supply means and tread rubber parts supply means. The means for supplying the band member and the means for supplying the belt/tread member are operative to cooperate with one another to continuously in series form a plurality of tires having different tire sizes.

Tire forming system and tire forming method

Disclosed are a tire/wheel assembly and a run-flat support member which are designed to be lightened without losing durability during run-flat traveling. The tire/wheel assembly is constituted as follows: a pneumatic tire is fit to a wheel rim; and the run-flat support member constituted of a circular shell and elastic rings is inserted into a cavity of the pneumatic tire. The circular shell has a support surface thereof extended toward the periphery of the pneumatic tire and leg portions along each side of the support surface. The elastic rings support the leg portions of the circular shell on the rim. In the tire/wheel assembly, contact portions and noncontact portions for the circular shell are alternately formed on the elastic rings in a shell circumferential direction.

Tire/wheel assembly and run-flat support member

A pneumatic tire for an automobile having a tread portion in a two-layered structure of a cap tread layer and an under tread layer, in which the under tread layer is constituted by a center region defined by a range of 30 through 70% of a width of a first belt layer and up to 0.5 through 2.0 mm in a tire diameter direction from a second belt layer and a shoulder region extended from both end portions of the first belt layer continuously from the center region to an outer side by 30 mm at maximum on one side and having a thickness of 1.0 through 5.0 mm, the regions comprising rubber composition members different from each other, the center region is arranged with a rubber layer where JIS-A hardness falls in a range of 65 through 80 and an amount of blending a softening agent relative to rubber 100 weight parts is smaller than that of the cap tread layer by 10 weight parts or more, the shoulder region is arranged with a rubber layer where JIS-A hardness falls in a range of 50 through 70 and the amount of blending the softening agent relative to rubber 100 weight parts is smaller than that of the cap tread layer by 10 weight parts or more and a ratio (tan &dgr; /tan &dgr; ) of loss tangent (tan &dgr; ) of the rubber layer of the shoulder region to loss tangent (tan &dgr; ) of the rubber layer of the center region is 2/3 or smaller.

Pneumatic tire for automobile and its fabrication method

A large number of sub-grooves inclining in the same direction as a tire rotating direction of a tire circumferential direction towards the outside of a car and extending in a tire width-wise direction are disposed on a tread surface of a tire the tire rotating direction of which is designated in one direction, and at least one main groove extending straight in the tire circumferential direction is disposed in an inside region of the tread surface inner than a tire center line. Further, semi-main grooves crossing the sub-grooves and inclining in an opposite direction to that of the sub-grooves are disposed at a predetermined pitch in the tire circumferential direction in an outside region of the tread surface outer than the tire center line. In this way, a pneumatic radial tire of the present invention has a block type tread pattern having asymmetric directionality.

Pneumatic radial tire having asymmetric tread pattern

A pneumatic tire for passenger cars, formed on its tread surface with at least one main groove extending in the circumferential direction of the tire, a number of sub-grooves extending in the widthwise direction of the tire, and a plurality of sub-main grooves extending at an angle of inclination within a range of 3.degree. to 30.degree. to the circumferential direction of the tire and to a length greater than a defined contact length of the tire, the or each main groove having a groove depth of 65% or more of the thickness of a tread rubber and a groove width which is greater than its groove depth and is within a range of 6 to 9% of a tread expansion width, each sub-main groove including such a wider or broader portion which has a groove depth of 65% or more of the thickness of the tread rubber and a groove width which is greater than its groove depth and is within a range of 3.5 to 6% of the tread expansion width, at least one protuberance being provided on each of the bottom of the main groove and the bottom of the wider or broader portion of the sub-main groove, extending along the main groove and the sub-main grooves.

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Hiratsuka, Japan

Eiichi Iida