Pneumatic radial tire reinforced with single wire steel cords of specific spiral shape
AssigneeThe Yokohama Rubber Co., Ltd.
InventorsSusumu Imamiya, Eiji Igarashi, Hisao Kato, Tomohiko Kogure
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Abstract
Pneumatic radial tires for automotive use are constructed with a belt layer reinforced with a steel cord of a unique structure. The steel cord results from the preformation of a single steel wire into a spiral shape meeting specified spiral parameters as determined by specified spiral diameters, specified wire diameters and specified spiral pitches. Significant weight saving is attainable with sufficient driving performance.
Claims5
A pneumatic radial tire comprising a tread portion, a carcass ply laid to turn about a pair of bead cores, and at least one circumferentially extending belt layer reinforced with an array of steel cords and interposed between said tread portion and said carcass ply, each of said steel cords consisting of a single steel wire and positioned in said belt layer at an angle with respect to the circumference of the tire, each of said steel wires being spirally preformed to meet the structural requirements set forth by the equation
- F=(D-d)/P,
- where
- 0.01.ltoreq.F.ltoreq.0.05,
- 0.28 (mm).ltoreq.d.ltoreq.0.05 (mm) and
- 2.0 (mm).ltoreq.P.ltoreq.8.0 (mm)
- wherein F is the determinant parameter of the optimal spiral of said steel wire, D is the diameter of the spiral of said steel wire measured in a direction perpendicular to the longitudinal direction thereof, d is the diameter of said steel wire and P is the pitch of the spiral along the length of said steel wire.
Dependencies are inferred from the claim text.