Bridgestone Corporation

Eiji Ichihara

Yusuke Nakamura

Naoto Kochi

Yoshinori Imamura

Takehiko Yamada

Juntarou Tamura

A first belt cord made of organic fibers of a spirally wound belt layer extends at an angle of equal to or less than 5° relative to a tire equatorial plane, a second belt cord made of organic fibers of a zigzag belt layer extends at an inclination of an angle of 2° to 45° relative to the tire equatorial plane, to folding back points where the second belt cord is folded back at each width directional end edge of the zigzag belt layer, and a relation of N>Nis satisfied. Nis the number of stacked belt layers of the spirally wound belt layers, at 50% of half the length of a maximum belt width of belt layers from the tire equatorial plane. Nis the number of stacked belt layers of the spirally wound belt layers, at 95% of half the length of the maximum belt.

Aircraft pneumatic tire

Provided is a pneumatic tire having excellent durability and driving stability during high-speed running of the vehicle (that is, during high-speed rotation of the tire). The pneumatic tire includes: a carcass; an intersecting belt which is provided on the outer circumference side of a crown portion of the carcass and formed of two inclined belt layers having cords inclined and extending in a direction intersecting each other across a tire equatorial plane; and a circumferential belt layer which is provided on either one of the inner side and the outer side of the intersecting belt in the tire radial direction and includes a spiral cord arranged as being spirally wound at an inclination angle of equal to or smaller than 5 degrees to the tire equatorial plane. Of the two inclined belt layers forming the intersecting belt, the cords in a first inclined belt layer are inclined at an inclination angle that falls within the range of 45 to 90 degrees relative to the tire equatorial plane, while the cords in a second inclined belt layer are inclined at an inclination angle that falls within the range of 15 to 45 degrees relative to the tire equatorial plane and is smaller than the inclination angle of the cords in the first inclined belt layer.

Pneumatic tire

Proposed is a pneumatic tire having excellent durability, handling stability and uneven wear resistance even if weight reduction is achieved by improving a belt. The pneumatic tire according to the present invention having a carcass layertoroidally extending from a tread portionthrough a side wall portionto a bead portion, and a belt layerdisposed at the outer side of the carcass layerin the tire radial direction, in which the carcass layerincludes one or more carcass plies, the belt layerincludes a first belthaving a first cordinclined with respect to a tire equator S at an angle in the range of 15&#xb0; to 75&#xb0; and a second belthaving a second cordextending in parallel to the tire equator S, said first belthaving a tensile strength smaller than that of the second belt

In tread-width-direction cross section under a standard internal pressure and no load condition, a point B is an outermost point of overlapping area in tread-width-direction, a line CC is a line passing through an outermost point CT of carcass layer in tread-width-direction and extending along tread-width-direction, a point C is a point of tire surface through the line CC, a line segment BW is a line segment extending in tread-width-direction from an equator center line to point B, a line segment CW is a line segment extending along tread-width-direction from equator center line to point C, and a line segment BC is a line segment connecting between point B and C. A ratio BW/CW between a length of BW and CW is not less than 0.6 and not more than 0.8. An angle &#x3b8; formed by BC and CW is not less than 50&#xb0; and not more than 70&#xb0;.

There are provided a process and the like for judging a residual lifetime of a run-flat tire and an end stage of the residual lifetime thereof during continuous running at a run-flat state. The process for judging the residual lifetime of the tire of the invention is characterized in that in a vehicle equipped with a run-flat tire system comprising run-flat tiresand detection unitseach arranged in the respective tireand capable of measuring an atmosphere temperature in at least an interiorof the tire, when the tireis continuously run at the run-flat state by an extreme lowering of an internal pressure accompanied with the occurrence of puncture or the like, after a limit temperature being statistically an occurrence of trouble is previously set, the atmosphere temperature inside tire of the run-flat tire continuously running at the run-flat state is measured, and a runnable time and/or distance until the run-flat tire results in trouble is predicted by using the atmosphere temperature inside tire measured and data calculated therefrom.

Method device and recording medium where program is recorded, for deciding residual travel life and end of life of run-flat tire that continues traveling in run-flat condition

Growing community of inventors

Kodaira, Japan

Eiji Ichihara