Pneumatic tire
AssigneeToyo Tire & Rubber Co., Ltd.
InventorsSeiichiro Heishi, Koji Takahira
Life of this patent
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Abstract
A pneumatic tire at least partially reinforced with steel cords. Most of steel filaments of said steel cords comprise iron materials having carbon content of 0.75 to 0.85 percent by weight. Said steel cords have an preferred tensile strength (TS) calculated from the following formula; ##EQU1## wherein W is the weight (g/m) of a steel cord, D is the diameter (mm) of the steel filament and N is the number of steel filaments of a steel cord and said steel cords also have a maintenance ratio of the knot strength of more than 60%.
Claims5
A pneumatic tire at least partially reinforced with steel cords comprising steel filaments SWRS 82 A, as specified by JIS G 3502, containing 0.80 to 0.85 wt. % C, 0.12 to 0.32 wt. % Si, 0.30 to 0.60% Mn, 0.025 wt. % max. P, 0.025 wt. % max. S and 0.20 wt. % max. Cu, most of said steel filaments of said steel cords comprising iron materials having non-metallic inclusions of 10.mu. or less for any given inclusion cross-section, said steel cords having the tensile strength calculated from the following formula:
- ##EQU6## wherein D is the diameter (mm) of the steel filament, N is the number of steel filaments of a steel cord, W is the weight (g/m) of a steel cord, TS is the tensile strength (kg) and the denominator 7.86 is the specific gravity of iron, and the maintenance ratio of the knot strength of said steel cords is more than 60%.
Dependencies are inferred from the claim text.