Bridgestone Corporation

Kazuomi Kobayashi

Kenji Matsuo

Tomohisa Nishikawa

Hiroki Sawada

Masahiro Hojo

Kazuo Oshima

Akira Yagi

Shuji Ando

Tatsuro Shimada

Katsuhiko Kinoshita

Kozo Sasaki

Shungo Ito

A heavy duty pneumatic tire, which allows the inside narrow-width belt layers to have a wide width as desired, and which suppresses the amount of strain generated at side edge portions of the belt layer to be sufficiently small thereby effectively preventing the separation of the belt layer, therefore the belt, in which two inside narrow-width belt layersB,B and two outside wide-width belt layersB,B, which have a larger width than the narrow-width belt layers, are sequentially disposed in the outer periphery side of the crown area of the radial carcass, wherein a portion of the wide-width belt layerB adjacent to the outer periphery side of the two narrow-width belt layersB,B, corresponding to side-edge vicinity of the narrow-width belt layerB of the outer periphery side is formed to be convex in radially outward direction.

Heavy duty pneumatic tire with wide-width belt layer convex portion

A heavy-duty pneumatic tire capable of sufficiently suppressing the amount of strain occurring in side edges of a belt layer is sufficiently suppressed, despite the required increase in width of the narrow belt layers on the inner layer side, so as to effectively prevent separation of the belt layer and, hence, separation of the belt. The tire includes two narrow belt layers (B,B) on the inner layer side, and two wide belt layers (B,B) on the outer layer side, which are larger in width than the narrow belt layers. The narrow belt layers and the wide belt layers are sequentially arranged on the outer circumferential side of a crown region of a radial carcass (). The innermost narrow belt layer (B) has side edges that are convex radially outwards.

Heavy-duty pneumatic tire

There is provided a pneumatic tire having an aspect ratio of not less than 60 and considerably improving run flat durability as compared with the conventional type of the run flat tire, wherein at least one cushion rubber layer having a loss tangent lower than a loss tangent (tan &#x3b4;) of a coating rubber for cords of a carcass ply is arranged between an end portion of a belt and a reinforcing rubber layer in a shoulder region and between mutually adjacent tire constitutional members. And also, when the carcass is comprised of plural plies, at least one ply is separated off in a zone beneath the belt, whereby the ride comfort against vibrations can be more improved.

Run flat pneumatic tire with shoulder cushion rubber layer loss tangent less than carcass coating rubber loss tangent

This invention is concerned with a radial tire, particularly a heavy duty radial tire aiming at the improvement of durability, and is characterized by rendering a ratio W/Wof width Wof a belt layer located side a carcass to width Wof the remaining belt layer in small slant belt layers arranged at a width corresponding to 0.25&#x2013;0.50 times a tread width in a widthwise direction of the tire, whereby growth and progress of cracks in the vicinity of cord ends of cords used in the belt resulting in separation failure at widthwise ends of the belt are effectively prevented to overcome a weak point in the tread reinforcement of the radial tire.

Radial tire including two small slant belt layers

Rubber composition and pneumatic tire using said rubber composition

A pneumatic tire having an aspect ratio of not less than 60 comprises a radial carcass of one or more plies, a belt, a bead filler rubber and a rubber reinforcing layer of substantially a crescent shape in section extending from a position near to a bead core to a position near to a tread end along an inner surface of an innermost carcass ply, wherein at least one rubber protection sheet being relatively soft is disposed between the bead filler rubber and the carcass ply surrounding it and/or between the rubber reinforcing layer and the carcass ply nearest thereto.

Pneumatic tires

In a heavy duty pneumatic radial tire having a lug pattern formed on both sides of a tread portion, each of lug grooves forming lugs is extended from a position separated from an equatorial plane of the tire by a given distance up to each of tread ends and has a platform on a region ranging from a top end portion near to the equatorial plane to a central portion in a longitudinal direction of the lug groove so as to satisfy such a surface shape that a groove depth at the top end portion is made shallower than a groove depth at the central portion.

Heavy duty pneumatic radial tire including lug groove having platform

Rubber-steel cord composite and pneumatic tire for passenger cars

There is provided a pneumatic tire having an aspect ratio of not less than 60 and considerably improving run flat durability as compared with the conventional type of the run flat tire, wherein at least one cushion rubber layer having a loss tangent lower than a loss tangent (tan &dgr;) of a coating rubber for cords of a carcass ply is arranged between an end portion of a belt and a reinforcing rubber layer in a shoulder region and between mutually adjacent tire constitutional members. And also, when the carcass is comprised of plural plies, at least one ply is separated off in a zone beneath the belt, whereby the ride comfort against vibrations can be more improved.

Pneumatic safety tire with rubber-organic filament fiber layer

A pneumatic tire for passenger cars comprises bead cores, a carcass layer, a tread portion, and side wall portions, wherein a rubber reinforcing layer having a crescent-shaped cross-section and at least one sheet of a rubber-filament fiber composite having a thickness measured under a pressure of 20 g/cm,of 0.05 to 2.0 mm which is formed from a rubber component and filaments having a diameter or a maximum cross-sectional dimension of 0.0001 to 0.1 mm and a length of 8 mm or more are disposed in said side wall portions. Reinforcing cords of carcass plies are made of an aliphatic polyamide fiber having a melting point of 250&deg; C. or higher.

Pneumatic tire for passenger cars with sidewall portions having a rubber reinforcing layer and a rubber-filament fiber composite

A pneumatic tire for a passenger car having a pair of bead portions, a toroidal carcass portion extending over both bead portions, at least two belt layers provided in a crown portion of the carcass, a tread portion positioned at an outer peripheral side of the belt layer, and side wall portions provided at the right and left sides of the tread portion, and which further includes a steel cord as a reinforcing material for reinforcing at least one layer of the carcass portion and the belt layer. The steel cord is formed by plying a plurality of filaments each having a strand diameter of 0.125 to 0.275 mm, and has an inflection point on an S&mdash;S curve. A reduction rate of a diameter of the steel cord under a load stress which is one third of breaking strength in comparison with a no load condition is equal to or more than 20%.

Pneumatic tire for passenger cars including specified steel cord

There is disclosed a safety pneumatic tire comprising a tire shell which is equipped with a toroidal carcass extending over a pair of bead portions and also functioning as a reinforcing material for a side wall portion connected to the bead portions and further for a tread portion, and which has a side-reinforcing layer on the internal surface of the side-wall portion; a rim which hermetically seals and supports the bead portions of the tire shell; and closed cell-based elastic foam which is filled in the internal hollow portion encompassed by the tire shell and the rim, wherein the constructional material of the elastic foam is butyl rubber or halogenated butyl rubber. The above safety pneumatic tire is markedly improved in run-flat durability, can reconcile favorable riding comfort chacteristic with the run-flat durability, is minimized in adverse influence upon the tire performances such as rolling resistance, and enables the production of a lightweight pneumatic tire.

Safety pneumatic tire

A pneumatic tire comprises a carcass of at least one rubberized ply of a radial arrangement, a belt comprised of two or more cross cord layers, a pair of thick reinforcing strip rubbers located at an inner face side of the carcass and a bead filler rubber, in which the reinforcing strip rubber and bead filler rubber have specified JIS hardness and rebound resilience, hardness ratio and maximum gauge ratio.

Growing community of inventors

Higashimurayama, Japan

Kazuomi Kobayashi