Sumitomo Rubber Industries Limited

Other

Sumitomo Electric Industries, Limited

Nippon Steel Sumitomo Metal Corporation

Sumitomo (sei) Steel Wire Corp.

Shinichi Miyazaki

Osamu Toda

Kazumi Yamazaki

Yasuo Sakai

Kiyoshi Ueyoko

Yuichi Sano

Takeshi Ohta

Keisuke Aramaki

Kenichi Okamoto

Junichi Kodama

Mikio Takatsu

Masato Komatsuki

Hiroshi Hoshino

Masayoshi Nishitani

Mamoru Uchida

Takao Wada

Tetsuya Kunisawa

Kazuki Numata

Toshiro Matsuo

Tetsuhiro Fukumoto

Hidehiko Hino

Tsuneyuki Nakagawa

Yukishige Adachi

Toru Iizuka

Narihiro Tahara

Keiichi Nakadera

Takuji Kusumoto

Haruyuki Sano

Ritsuo Nakayasu

Takao Otani

Keiichi Makino

Toshiaki Yamamoto

Makoto Ishii

A pneumatic tire capable of reducing rolling resistance and discharging static electricity generated during running, wherein each of a tread rubber, a breaker rubber, and a sidewall rubber formed on the tread part, the breaker part, and the sidewall part, respectively, has a volume specific resistivity of 1&#xd7;10&#x3a9;&#xb7;cm or more, the pneumatic tire further including a conduction rubber embedded in the tread part so as to be at least partially exposed to a surface of the tread part, bead part rubber disposed at a region contacting a rim flange of the bead part, and electroconductive rubber electrically connecting the conduction rubber to the beat part rubber, wherein each of the conduction rubber, the bead part rubber, and the electroconductive rubber has a volume specific resistivity of less than 10&#x3a9;&#xb7;cm.

Pneumatic tire

Rubber-cord complexhaving improved wet heat adhesive property between rubber and cord. The rubber-cord complex includes cordcomprising drawn plated wireprepared by providing brass plated layerE on surface of element wireand drawing the resulting plated wire and rubbervulcanized and bonded to cord. The rubber-cord complexhas adhesion reaction layer(formed by cross-linking sulfur and copper) between rubberand brass plated layerE. Adhesion reaction layerhas average thickness of 50-1,000 nm. Interface S between adhesion reaction layerand the rubber has a fractal dimension of 1.001-1.300 in a wet heat deterioration state after being subjected to vulcanization to bond rubberthereto and being held at a temperature of 50-100&#xb0; C. and a humidity of 60-100% for one hour to 20 days.

Metal cord, rubber-cord complex and pneumatic tire using the same

A rubber-cord complex having an improved wet heat adhesive property between a rubber and a cord comprising a drawn plated wire, and including a metal cord comprising a drawn plated wire prepared by providing a brass plated layer on the surface of an element wire and drawing the resulting plated wire, and a rubber vulcanized and bonded to the cord, wherein in a wet heat deterioration state of the drawn plated wire after being subjected to the vulcanization to bond the rubber thereto and further held under an atmosphere having a temperature of 50 to 100&#xb0; C. and a humidity of 60 to 100% for one hour to 20 days, the average grain size of crystal grains present in the brass plated layer is not more than 50 nm, and the grain boundary of the crystal grains has a fractal dimension of 1.001 to 1.500.

The heat resistance of carcass cords is enhanced, whereby the runflat durability is enhanced. A pneumatic tire has a carcassand a tread-reinforcing cord layerdisposed radially outward of the carcass, the carcasscomprising a carcass plyA in which carcass cordsof aramid fiber are arranged at an angle of 45 to 90&#xb0; with respect to the tire circumferential direction and are covered with a topping rubber, preferable carcass cordshave a two-bundle twisted structure that two bundles of first-twisted filaments are subjected to final twist, and preferable carcass cordshave a twist factor T of 0.5 to 0.7 represented by the equation (1):&#xd7;&#x221a;{square root over ({(0.125&#xd7;/2)/&#x3c1;})}&#xd7;10&#x2003;&#x2003;(1)in which N is the number of final twists per 10 cm, D is a total nominal dtex (fineness) of a cord, and &#x3c1; is a specific gravity of a cord material.

The pneumatic tire of the present invention, in which a tread rubber, a sidewall rubber, and a breaker rubber each have an intrinsic volume resistivity of 1&#xd7;10&#x3a9;&#xb7;cm or more, a clinch rubber and a chafer rubber each have an intrinsic volume resistivity of 1&#xd7;10&#x3a9;&#xb7;cm or less, wherein the pneumatic tire has a first conductive layer that is disposed between a carcass ply, an edge portion of the breaker rubber and the sidewall portion, a second conductive layer that is in contact with the first conductive layer and is disposed between the tread rubber and the carcass, and a pen rubber layer that extends from the second conductive layer to a surface of the tread portion, wherein the first conductive layer, the second conductive layer, and the pen rubber layer each have an intrinsic volume resistivity of 1&#xd7;10&#x3a9;&#xb7;cm or less, the carcass ply contains a conductive fibrous material having an intrinsic volume resistivity of 1&#xd7;10&#x3a9;&#xb7;cm or less and has a structure that the carcass ply is in contact with the clinch portion, the chafer portion, and the first conductive layer.

A pneumatic tire includes a carcass ply with carcass cords. The carcass cords comprise high tenacity vinylon fiber, polyethylene naphthalate fiber or polyalylate fiber. Viscoelasticity characteristics per one cord at 120&#xb0; C. of the carcass cord satisfy the following equations (1) to (3):B&#x3e;0&#x2003;&#x2003;(1)&#x2266;0.0000437&#xd7;+0.042857&#x2003;&#x2003;(2)&#x2266;&#x2212;0.00003636&#xd7;+0.163636&#x2003;&#x2003;(3)(wherein 'A' represents a product of complex modulus E*(N/cm) and cross-sectional area 'S' (cm) of cord), and &#x201c;B&#x201d; represents a loss tangent tan&#x3b4;).

A runflat tire having an improved runflat durability and including sidewall-reinforcing rubber layerhaving a crescent-shaped cross section disposed axially inward of carcassin sidewall portion, wherein the carcasscomprises at least one carcass plyA in which carcass cords made of an aramid fiber or a polyethylene naphthalate fiber are arranged at an angle of 70 to 90&#xb0; with respect to the circumferential direction and are covered with a topping rubber.

Runflat tire

A pneumatic tire comprises a cord-reinforced layer such as carcass, belt, bead reinforcing layer which is made of metallic cords, each metallic cord is made up of six to twelve metallic filaments whose diameter is in a range of from 0.15 to 0.45 mm, the metallic filaments include waved filaments and unwaved filaments, each waved filament is two-dimensionally waved at a wave pitch and wave height before twisted, the wave pitch is in a range of from 5.0 to 35.0 times the diameter of the filament, and the wave height is in a range of from 0.2 to 4.0 times the diameter of the filament, and the metallic filaments are twisted together into the cord at a twist pitch of from 10 to 40 mm so that the two-dimensionally waved filaments are each subjected to a certain rotation around its axial.

A pneumatic tire is provided which includes a carcass extending between bead portions, and a belt disposed radially outside the carcass in the tread portion. At least one of the carcass and belt includes a cord ply of a polyethylene-2,6-naphthalate fiber cord. The polyethylene-2,6-naphthalate fiber cord has a total denier number of from 2500 to 3600, a twist number of from 30 to 40 turns/10 cm, an initial stage modulus at 25 deg. C. in a range of from 50 to 65 gf/d, and a variation of the initial stage modulus at between 25 to 70 deg. C. which is not more than 20% in absolute value.

A method of manufacturing a rubber reinforcing steel cord is provided, wherein the steel cord has a steel wire plated with metal containing copper and having on its surface an oil layer containing a cobalt compound, and includes an application step in which the oil containing a cobalt compound is applied to the steel wire or a steel cord plated with metal containing copper, and a step of twisting the steel wires.

Rubber reinforcing steel cord, manufacturing method of rubber reinforcing steel cord and pneumatic tire

A metal cord for reinforcing rubber articles and a pneumatic tire including metal cords to reinforce tire components such as carcass, breaker and band are disclosed, wherein a metal cord according to one aspect of the present invention comprises filaments having a tensile strength of from 4000 to 5500 N/sq.mm and a diameter of from 0.10 to 0.35 mm and the filaments are twisted together, the filaments before twisted are two-dimensionally waved so that the elongation after fracture of the cord becomes in a range of from 2 to 6%. According to another aspect of the present invention, the metal cord is a single filament having a tensile strength of from 4000 to 5500 N/sq.mm and a diameter D of from 0.10 to 0.35 mm, and the filament is two-dimensionally waved so that the elongation after fracture becomes in a range of from 2 to 6%.

Metal cord and pneumatic tire including the same

The present invention provides a metallic cord for reinforcing a tire moldable in a tire manufacturing step without complicating operations and keeping strength by reducing rusting and an excellent pneumatic tire employing the metallic cord. The inventive metallic cord for reinforcing a tire is formed by shaping a bundle prepared by paralleling a plurality of metallic wires having substantially circular sections in an unstranded state with a binder of a polymer material having a melting point of 50&#xb0; C. to 200&#xb0; C. The polymer material is preferably low-density polyethylene or medium-density polyethylene. The diameters of the metallic wires are preferably 0.15 to 0.3 mm.

Metallic cord and pneumatic tire employing the metallic cord

A pneumatic tire containing a belt disposed radially outside a carcass in a tread portion, the belt including two cross plies of monofilament metallic cords laid at angles of from 15 to 30 degrees with respect to the circumferential direction of the tire, each monofilament cord composed of a waved single filament, the filament having a circular sectional shape having a diameter in the range of from 0.40 to 0.50 mm, or alternatively a non-circular sectional shape having an aspect ratio in the range of from 0.65 to 0.95 and a cross-sectional area in the range of 0.09 to 0.20 sq.mm.

Pneumatic tire with monofilament metallic belt cords

A steel cord is composed of three to six steel filaments each having a filament diameter of from 0.25 to 0.45 mm, the three to six steel filaments including shaped filaments and twisted together, wherein the shaped filaments are, before twisted together, coiled to be set in a form of coil having a coil diameter of less than 5 mm and a coil pitch of more than 5 mm, the shaped filaments include at least two kinds of shaped filaments which are different in respect of the form of coil, the shaped filaments are twisted together while the coil diameter is reduced, the elongation of the cord at 50 N load is less than 0.2%, and the cord strength is in a range of from 2500 to 3500 N/sq.mm.

Growing community of inventors

Kobe, Japan

Shinichi Miyazaki