# US 2012/0073721 A1 · Rubber-steel cord composite and tire using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2012/0073721 A1 - Document ID: US20120073721A1 - Status: Published application - Kind: A1 - Application number: 13/311,618 - Filed: 2011-12-06 - Published: 2012-03-29 - Earliest claimed: 2006-01-20 - Assignees: Bridgestone Corporation - Inventors: Hiroki ISHIZAKA; Kiyoshi IKEHARA - Web page: https://patentgrep.com/patent/US20120073721A1 ## CPC - D07B 1/0646: {comprising longitudinally preformed wires} - B60C 9/0007: {Reinforcements made of metallic elements, e.g. cords, yarns, filaments or fibres made from metal} - B60C 9/005: {Reinforcements made of different materials, e.g. hybrid or composite cords} - B60C 9/2006: {consisting of steel cord plies only} - D07B 1/0613: {the reinforcing cords being characterised by the rope configuration} - D07B 1/062: {the reinforcing cords being characterised by the strand configuration} - D07B 1/16: Ropes or cables with an enveloping sheathing or inlays of rubber or plastics (D07B1/04, D07B1/10 take precedence) - B60C 2200/06: for heavy duty vehicles - B60C 2200/10: for motorcycles, scooters or the like - D07B 2201/1092: Parallel strands - D07B 2201/2007: characterised by their longitudinal shape - D07B 2201/2008: wavy or undulated - D07B 2201/2011: comprising metals - D07B 2201/2021: characterised by their longitudinal shape - D07B 2201/2022: coreless - D07B 2201/2033: Parallel wires - D07B 2201/2044: comprising polymers - D07B 2205/3089: Brass, i.e. copper (Cu) and zinc (Zn) alloys - D07B 2401/2005: Elongation or elasticity - D07B 2501/2046: Tyre cords - Y10T 152/10765: Characterized by belt or breaker structure - Y10T 152/1081: Breaker or belt characterized by the chemical composition or physical properties of elastomer or the like - D07B: ROPES OR CABLES IN GENERAL (joining ropes or cables to one another or to other objects B65H69/00, F16G11/00; {mountaineering ropes A63B29/02}; mechanical finishing or dressing of ropes D02J; {braiding D04C}; decorative ropes or cords D04D; suspension cables for bridges E01D19/16; specially adapted for driving, or for being driven by, pulleys or other gearing elements F16G9/00; electric cables or joints insofar as electrical aspects are essential H01B, H01R) - B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A rubber-steel cord composite is provided having nonlinear physical properties even in a rubber characterized by incompressive properties after vulcanization, and hence the rubber-steel cord composite can show low rigidity and flexible properties in a low-strain region and, on the other hand, can show high rigidity in a high-strain region. The rubber-steel cord composite is provided by bundling steel linear objects 1 subjected to spiral shape forming at substantially identical pitches in an approximately identical phase without twisting, the steel cord being embedded in rubber. ## Claims ### Claim 1 A motorcycle pneumatic radial tire comprising: a tread portion; a pair of sidewall portions provided from both edge portions of the tread portion to the inside in a tire radius direction; and bead portions ranging from the sidewall portions to the inside in the tire radius direction, in which a carcass layer, which reinforces these portions between bead cores embedded in the respective bead portions and which is formed of at least one carcass ply composed of rubber and cords coated thereby inclined by 60° to 90° with respect to the equatorial plane of the tire, and a spiral belt layer including at least one layer, which is provided outside the carcass layer in the tire radius direction and which is formed by spirally winding substantially parallel to the equatorial plane of the tire, are included, wherein the spiral belt layer comprises the rubber-steel cord composite comprising: at least one steel cord provided by bundling a plurality of steel linear objects subjected to spiral shape forming at substantially identical pitches in an approximately identical phase without twisting, the steel cord being embedded in rubber. ### Claim 2 A motorcycle pneumatic radial tire comprising: a tread portion; a pair of sidewall portions provided from both edge portions of the tread portion to the inside in a tire radius direction; bead portions ranging from the sidewall portions to the inside in the tire radius direction, in which a carcass layer, which reinforces these portions between bead cores embedded in the respective bead portions and which is formed of at least one layer of carcass ply composed of rubber and cords coated thereby inclined by 60° to 90° with respect to the equatorial plane of the tire, and a spiral belt layer including at least one layer, which is provided outside the carcass layer in the tire radius direction and which is formed by spirally winding substantially parallel to the equatorial plane of the tire, are included, wherein the spiral belt layer comprises a rubber-steel cord composite in which at least one steel cord composed of steel linear objects is embedded in rubber, and in strain-load characteristics in the state in which the rubber adheres the inside of a circumscribed circle of the steel cord, the elongation amount obtained by changing an application load W from 1,500×S(N) to 1,600×S(N) is 0.070% or less, where S (mm2) indicates a steel portion cross-sectional area of the steel cord, and an application load W1 (N) at an elongation of 0.35% and an application load W2 (N) at an elongation of 0.45% satisfy the following equation W2−W1<35·S. ### Claim 3 (depends on 2) The motorcycle pneumatic radial tire according to claim 2, wherein, in the strain-load characteristics in the state in which the rubber adheres the inside of a circumscribed circle of the steel cord, the elongation amount is 0.065% or less when the application load W is changed from 1,500×S(N) to 1,600×S(N). ### Claim 4 (depends on 2) The motorcycle pneumatic radial tire according to claim 2, wherein, in the strain-load characteristics in the state in which the rubber adheres the inside of a circumscribed circle of the steel cord, the application load W1 (N) at an elongation of 0.35% and the application load W2 (N) at an elongation of 0.45% satisfy the following equation W2−W1<20·S. ### Claim 5 (depends on 2) The motorcycle pneumatic radial tire according to claim 2, wherein the steel linear objects comprise steel filaments, steel strands provided by twisting steel filaments, or the combination therebetween, and the steel cord is provided by bundling the steel linear objects subjected to spiral shape forming at substantially identical pitches in an approximately identical phase without twisting. ### Claim 6 (depends on 5) The motorcycle pneumatic radial tire according to claim 5, wherein a circumscribed circle of a formed spiral shape of an optional one of the steel linear objects and a circumscribed circle of a formed spiral shape of at least one of the other steel linear objects are overlapped with each other. ### Claim 7 (depends on 5) The motorcycle pneumatic radial tire according to claim 5, wherein the structures and the shape forming amounts of the steel linear objects are all identical to each other. ### Claim 8 (depends on 5) The motorcycle pneumatic radial tire according to claim 5, wherein the following equation is satisfied D>2.5d where D indicates the diameter of a circumscribed circle of the formed spiral shape of the steel linear objects, and d indicates the outer diameter of the steel linear objects. ### Claim 9 (depends on 2) The motorcycle pneumatic radial tire according to claim 2, wherein the steel linear objects comprise steel filaments, steel strands provided by twisting steel filaments, or the combination therebetween, the steel cord is provided by twisting two to five of the steel linear objects subjected to excessive shape formation, and in a circumscribed circle of the steel cord in a cross-section perpendicular to the longitudinal direction thereof, the center angle with respect to an arc between the steel linear objects is 180° or more. ### Claim 10 (depends on 9) The motorcycle pneumatic radial tire according to claim 9, wherein the following equation is satisfied D>2.5d where D indicates the diameter of the circumscribed circle of the steel cord, and d indicates the outer diameter of the steel linear objects forming the steel cord. ### Claim 11 (depends on 2) The motorcycle pneumatic radial tire according to claim 2, wherein the steel linear objects wound around separate reels are bundled by being passed through one mouth ring to form the steel cord, and the steel cord is coated by rubber and is then embedded in a rubber composite, whereby the rubber-steel cord composite is manufactured. ### Claim 12 (depends on 2) The motorcycle pneumatic radial tire according to claim 2, wherein the steel linear objects wound around separate reels are bundled by being passed through one slit to form the steel cord, and after rubber is pressure-bonded to the steel cord from the top and the bottom, the steel cord is then embedded in a rubber composite, whereby the rubber-steel cord composite is manufactured.