Rubber-steel cord composite and tire using the same
AssigneeBridgestone Corporation
InventorsHiroki ISHIZAKA, Kiyoshi IKEHARA
Life of this patent
Estimating the term…
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.
Claims12
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.
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.
Dependencies are inferred from the claim text.