Bridgestone Corporation

Bridgestone Metalpha Corporation

Naohiko Obana

Yoshikazu Kaneko

Shuichi Onuma

Motonori Bundo

Kazuto Fujita

Sumito Nakagawa

Hideki Masubuchi

Noboru Kusaba

Takao Morii

Ryuzo Osawa

Masuhiro Fujita

Toshiyuki Kobayashi

Chihiro Yoshida

Mikito Kondo

Yoshiaki Oono

The present invention provides a metal cord having better adhesion to rubber compared to a conventional one, as well as a metal cord-rubber composite and a conveyor belt, including the same. In a metal cord () composed of a plurality of metal filaments () twisted together, the surfaces of the metal filaments () constituting the outermost layer are each provided with a zinc plating layer (), and the degrees of crystal orientation of the (002) plane and the (102) plane of the surface of the zinc plating layer () are less than 120.

Metal cord, metal cord/rubber composite and conveyor belt

Rubber article-reinforcing steel cord in which corrosion resistance is improved without an increase in weight. In a rubber article-reinforcing steel cord (), plural sheath strands () each formed by twisting together plural steel filaments are twisted together around at least one core strand () formed by twisting together plural steel filaments. Core strand () and sheath strands () are each formed by twisting together one or two core filaments () and () and plural sheath filaments () and (), respectively, and a relationship represented by the following Formula (1) is satisfied when a wire diameter of core filament(s) () of core strand (), a wire diameter of sheath filaments (), a wire diameter of core filaments () of sheath strands (), and a wire diameter of sheath filaments () are defined as dcc, dcs, dsc and dss, respectively: dcc&#x3e;dcs&#x2265;dsc&#x3e;dss (1).

Rubber component reinforcing-steel cord

Provided is a multi-twisted steel cord for reinforcing a rubber article, the steel cord having cord strength with a small loss as compared to the total strength of filaments constituting the cord and a high rubber penetration. The steel cord includes a plurality of twisted strands in a multi-twisted structure, each strand including a plurality of twisted filaments in two or more layers, in which at least some of the filaments have a tensile strength of 3,000 MPa or more, the steel cord satisfying a filament occupancy of 48% or more and less than 54%, a cord twist angle of 78&#xb0; or more and less than 84&#xb0;, an average crossing angle between adjacent filaments other than wrapping filaments of less than 17&#xb0;, and a gap between adjacent sheath filaments constituting the strand of 0.065 mm or more.

Steel cord for reinforcing rubber article, method for manufacturing same, and tire

Provided are a rubber article reinforcing steel wire that is superior in bending fatigue properties to the related art and has a flat cross-sectional shape, and a rubber article using the wire. In a rubber article reinforcing steel wire, a major diameter and a minor diameter are substantially perpendicular to each other. Assuming that the major diameter is W, the minor diameter is T, a straight line that passes through a center of the major diameter in a width direction and is parallel to a minor diameter direction is L1, a straight line that passes through a center of the minor diameter in a width direction and is parallel to a major diameter direction is L2, an intersection point of the L1 and the L2 is a center point C, a region within a half of a distance from the center point C to a surface is a central region Rc, and a region outside the central region Rc is a surface layer region Rs, a Vickers hardness Hvc of the central region Rc is more than a Vickers hardness Hvs of the surface layer region Rs; and assuming that a Vickers hardness on the L1 in the surface layer region Rs is Hv1, and a Vickers hardness on the L2 in the surface layer region Rs is Hv2, relationships represented by Hvc&#x2212;Hv1&#x2266;150, Hvc&#x2212;Hv2&#x2266;150, Hv1/Hvc&#xd7;100&#x2267;85.11, and Hv2/Hvc&#xd7;100&#x2267;79.84 are satisfied.

Rubber article reinforcing steel wire and rubber article using same

A rubber-covered belt ply forms a belt layer. At least a majority of metal wires in the ply exist as metal wire bundles in which a plurality of metal wires of circular cross-sections and substantially equal wire diameters are aligned in parallel without being twisted together, the metal wire bundles being aligned planarly and in parallel with intervals between the metal wire bundles in a transverse direction. At least one layer, which is a cap layer in which organic fibers are covered with rubber and/or a reinforcing layer which is formed of rubber or whose main component is rubber, is disposed between the belt layer and a tread.

Radial tire

A steel wire, 0.10-0.40 mm in diameter, obtained by subjecting a high-carbon (0.70-0.90 wt. %) steel wire material to heat treatment and wire drawing, wherein its tensile strength and test values of special repeated torsional tests satisfy a predetermined relation; and a method of manufacturing the same. A high strength steel wire which has so high a ductility as to substantially prevent the wire from being broken even during wire twisting, and which rarely encounters a decrease in the ductility even after the wire has been subjected to age hardening by heating, is obtained, and a method of manufacturing the same is economical.

Steel wire and method of manufacturing the same

As the present invention there is disclosed a pneumatic radial tire comprising a carcass having a smaller tensile rigidity than that of conventional pneumatic radial tires by application of a steel cord having a smaller Young's modulus to the carcass or by application of a smaller amount of a high strength steel cord formed with carcass filaments having a greater tensile strength to the carcass while maintaining the necessary strength of the carcass. In accordance with the present invention, extension of the carcass increases and extension of a belt in the circumferential direction of the tire is suppressed when the tire is inflated by an inner pressure. As a result, compression stress working on the carcass when a vehicle turns decreases and buckling deformation of the steel cord can be prevented. Accordingly, durability is improved. The amount of the cord required to maintain the strength of the carcass can be decreased by application of the high strength steel cord, thereby decreasing weight of the tire.

Pneumatic radial tire

Steel cord is manufactured by: forming a plurality of bends, per filament length equivalent to one twist pitch, on each of filaments which constitute an outer layer sheath, with the filament length equivalent to one twist pitch being a cycle; twisting these filaments while the bends belonging to the same phase are aligned in a cord axial direction; and subjecting cord side surfaces to compression processing. As a result, flat side surface portions are formed, in which a plurality of filaments forming the outer layer sheath are positioned substantially in the same plane. The steel cord thus formed is used in reinforcement plies for pneumatic radial tires such that the reinforcement plies are laminated in a manner in which the flat side surface portions are mutually parallel.

Steel cord having flat side surface portion, method of manufacturing same, and pneumatic tire reinforced with same

A steel cord comprises a core of three or more filaments bundled without twisting and a sheath of at least one layer comprised of plural filaments wound around the core, wherein all core filaments are arranged in a given rectangle at any section in its longitudinal direction. Such steel cords are used in a belt of a pneumatic tire. And also, these cords are produced by a tubular-type twisting machine having a specified structure.

Steel cords for reinforcement of rubber articles pneumatic tire process for producing steel cord and tubular-type twisting machine therefor

Corrosion resistant steel cords and pneumatic tires reinforced with same

A steel cord for reinforcing a rubber product includes a core consisting of one steel filament and a sheath consisting of a plurality of steel filaments wound around the core. The steel filament of the core alternately having straight portions, whose axes of the straight portions are disposed on one line, and protrusions formed by bending. The peak of each protrusion is disposed outside of the sheath. The steel cord for reinforcing a rubber product is used in a pneumatic tire. The pneumatic tire includes a carcass having a crown portion and having a toroidal shape, a pair of beads over which the toroidal shape extends, a belt layer or belt layers for reinforcing the crown portion of the carcass, and rubber surrounding the carcass, the pair of bead, and the belt layer(s). The steel cord is used in the carcass and/or the belt layer(s).

Steel cord for reinforcing rubber product and pneumatic tire using such

A steel cord intended for use to reinforce rubber products is produced by drawing, into a steel filament of 0.10 to 0.40 mm in diameter and more than 3,000 N/mm.sup.2 in strength, a wire rod having a carbon content of more than 0.70% by weight, and twisting a plurality of such steel filaments together. Also a pneumatic tire is provided which employs in at least a portion of a reinforcing member thereof the steel cord improved in corrosion resistance and having an R.sub.1 /R.sub.0 ratio .times.100 which is less than 100, where R.sub.0 is the radius of spiral curvature of the spiraled steel filament resulting from untwisting said steel cord and R.sub.1 is the radius of spiral curvature of said steel filament of which the surface layer inside the spiral is removed by dissolving.

Tire having corrosion resistant steel cord

A steel cord intended for use to reinforce rubber products is produced by drawing, into a steel filament of 0.10 to 0.40 mm in diameter and more than 3,000 N/mm.sup.2 in strength, a wire rod having a carbon content of more than 0.70% by weight, and twisting a plurality of such steel filaments together. Also a pneumatic tire is provided which employs in at least a portion of a reinforcing member thereof the steel cord improved in corrosion resistance and having an R.sub.1 /R.sub.0 ratio.times.100 which is less than 100, where R.sub.0 is the radius of spiral curvature of the spiraled steel filament resulting from untwisting said steel cord and R.sub.1 is the radius of spiral curvature of said steel filament of which the surface layer inside the spiral is removed by dissolving.

Corrosion resistant steel filament

A steel cord intended for use to reinforce rubber products is produced by drawing, into a steel filament of 0.10 to 0.40 mm in diameter and more than 3,000 N/mm.sup.2 in strength, a wire rod having a carbon content of more than 0.70% by weight, and twisting a plurality of such steel filaments together. Also a pneumatic tire is provided which employs in at least a portion of a reinforcing member thereof the steel cord improved in corrosion resistance and having an R.sub.1 /R.sub.0 ration.times.100 which is less than 100, where R.sub.0 is the radius of spiral curvature of the spiraled steel filament resulting from untwisting said steel cord and R.sub.1 is the radius of spiral curvature of said steel filament of which the surface layer inside the spiral is removed by dissolving.

Corrosion resistant spiral steel filament and steel cord made therefrom

A steel cord for the reinforcement of rubber articles exhibits largely different bending rigidities in two crossing directions at section of the cord and comprises a bundle of plural strands each being obtained by twisting 3 or more steel filaments and a wrapping filament helically wound around the bundle. The steel filaments have a twisting pitch in the range of 3.0 to 30.0 mm. A single wrapping filament is helically wound around the bundle at a twisting pitch of 2.0-15 mm. Various cord structures may be used, for example, 1.times.3, 1.times.5, 2+6 and 3.times.4.

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Tokyo, Japan

Naohiko Obana