A dynamic wireless power transfer system includes a power transmission coil, a power transmission circuit, a power reception coil, a power reception circuit, and a relay circuit. The power transmission coil is provided in a road. The power transmission circuit supplies electric power to the power transmission coil. The power reception coil is provided in a vehicle. The power reception circuit is connected to the power reception coil. The relay circuit transfers electric power between the power transmission coil and the power reception coil in a contactless manner.

A steel cord containing a core layer and an sheath layer, the core layer containing a plurality of core wires with a number of n and the sheath layer comprises a plurality of sheath wires with a number of m, and the steel cord has a flat cross-section with a major axis and a minor axis, the flat cross-section has a flat ratio being the ratio of the length of the major axis and the length of the minor axis, the flat ratio is more than 1.2, the steel cord has a breaking load being BL.sub.cord, the core wires and the sheath wires have a sum breaking load being Sum BL.sub.wires when the core wires and the sheath wires are un-twisted from the steel cord, BL.sub.cord and Sum BL.sub.wires satisfies the following formula: BL.sub.cord/Sum BL.sub.wires>96%. The steel cord has higher breaking load.

A tire (1) for an agricultural vehicle, having a crown reinforcement (3), with at least two crown layers (31, 32), each having metal reinforcers which are coated in an elastomer material. Any metal reinforcer of a crown layer (31, 32) has a law, known as a bi-modulus law, governing its elastic behaviour under tension, comprising a first portion having a first extension modulus MG1 at most equal to 30 GPa, and a second portion having a second extension modulus MG2 at least equal to 2 times the first extension modulus MG1, and any metal reinforcer of a crown layer (31, 32) has a law governing its behaviour under compression that is characterized by a critical buckling strain EU at least equal to 3%.

A two-layer multi-strand cord (60) comprises an internal layer (CI) of the cord made up of J>1 internal strands (TI) and an external layer (CE) of the cord made up of L>1 external strands (TE). The cord satisfies the relationship 95≤MC≤180, where MC=(J×MI+L×ME)/(J+L); MI=200×cos.sup.4(α)×[Q×(D1/2).sup.2×cos.sup.4(β)+P×(D2/2).sup.2×cos.sup.4(δ)+N×(D3/2).sup.2×cos.sup.4(γ)]/[Q×(D1/2).sup.2+P×(D2/2).sup.2+N×(D3/2).sup.2]; and ME=200×cos.sup.4(α′)×[Q′×(D1′/2).sup.2×cos.sup.4(β′)+P′×(D2′/2).sup.2×cos.sup.4(δ′)+N′×(D3′/2).sup.2×cos.sup.4(γ′)]/[Q′×(D1′/2).sup.2+P′×(D2/2).sup.2+N′×(D3′/2).sup.2], where D1, D1′, D2, D2′, D3 and D3′ are in mm, α and α′ are the helix angle of each internal and external strand (TI), β and β′ are the helix angle of each internal thread (F1, F1′), δ and δ′ are the helix angle of each intermediate thread (F2, F2′) and γ and γ′ are the helix angle of each external thread (F3, F3′).

The invention relates to a multi-strand cord (50) comprising an internal layer (CI) of the cord made up of K=1 three-layer (C1, C2, C3) internal strand (TI), with the internal layer (C1) being made up of Q internal metallic threads (F1), the intermediate layer (C2) being made up of M intermediate metallic threads (F2) and the external layer (C3) being made up of N external metallic threads (F3), and an external layer (CE) of the cord made up of L>1 three-layer (C1′, C2′, C3′) external strands (TE) wound around the internal layer (CI) of the cord, with the internal layer (C1′) being made up of Q′ internal metallic threads (F1′), the intermediate layer (C2′) being made up of M′ intermediate metallic threads (F2′) and the external layer (C3′) being made up of N′ external metallic threads (F3′).

The cord (50) has: an endurance criterion SL≤40 000 MPa.Math.mm with

[00001]$SL=\max \left(\frac{\Delta {\sigma }_{\mathrm{bending}\_\mathrm{CI}}}{\mathrm{Cp}};\frac{\Delta {\sigma }_{\mathrm{bending}\_\mathrm{CE}}}{C_r\times \mathrm{Cp}}\right);$  and a size criterion Ec≥0.46 with Ec=Sc/Se.

In a pneumatic tire, a plurality of belt layers disposed on an outer circumferential side of a carcass layer in a tread portion are formed of steel cords each having a 1×M structure formed of a number of wire strands. The number of wire strands corresponds to one to six wire strands. A tensile modulus of elasticity of the steel cords under 5 N to 50 N load is 130 GPa or more. The steel cords are arranged inclined with respect to a tire circumferential direction to intersect each other in layers of the belt layers. The belt cover layer disposed on an outer circumferential side of the belt layers is formed of organic fiber cords having elongation of 2.0% to 4.0% under 2.0 cN/dtex load. The organic fiber cords are wound helically along the tire circumferential direction.

A rubber-steel cord composite in which a rubber composition and a steel cord are vulcanized and adhere to each other, wherein the rubber composition contains 1 to 10 parts by mass of a vulcanizing agent, 0.1 to 5 parts by mass of N,N-dibenzylbenzothiazole-2-sulfenamide, and 0.1 to 5 parts by mass of a bismaleimide compound, with respect to 100 parts by mass of diene rubber containing natural rubber.

A rubber-steel cord composite according to an embodiment is formed by vulcanizing and bonding a rubber composition containing 1 to 10 parts by mass of sulfur, 0.1 to 5 parts by mass of N,N-dibenzylbenzothiazole-2-sulfenamide, and 0.1 to 5 parts by mass of either one or both of hexamethylene bis-thiosulfate disodium salt dihydrate and 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane, with respect to 100 parts by mass of diene rubber containing natural rubber, and a steel cord. A pneumatic tire according to an embodiment includes the rubber-steel cord composite.

Polybenzoxazine comprises repeat units which comprise at least one unit corresponding to the formulae (I) or (II): ##STR00001##
in which Z.sub.1 and Z.sub.2, which are identical or different, represent an at least divalent, aliphatic, cycloaliphatic or aromatic bonding group comprising at least one carbon atom and optionally at least one heteroatom selected from O, S, N and P. Such a polybenzoxazine may be used as a metal-adhesive layer, in particular for the adhesive bonding of a metal substrate, in particular made of carbon steel, to a rubber.

Provided is a motorcycle tire, that provides excellent steering stability while using steel cords as a belt layer material, which comprises a carcass extending from a tread portion to a bead core of a bead portion via a sidewall portion, and a belt layer arranged outside the carcass and inside the tread portion in the tire radial direction, wherein the belt layer is a steel belt layer having steel cords; the steel cord is a steel cord having an m×n configuration in which n strands, formed by twisting m steel filaments, are twisted together in the same direction as the steel filaments, and the m is 1 or more and 3 or less and n is 2 or more and 6 or less; the diameter of the steel filament is 0.15 mm or more and 0.25 mm or less; the rubber composition forming the tread portion is a rubber composition having a complex elastic modulus E* (MPa) of 5.0 MPa or more; and the product (S×E*) of the total cross-sectional area S(mm.sup.2) of the steel filaments in the cross section of the steel cord and the complex elastic modulus E* (MPa) is 2.00 or less.