| 摘要 |
A steel cord which has no production problem noted in the related art and which can be produced efficiently with stable quality, particularly a steel cord useful for the purpose of reinforcing a tire crown portion, as well as a composite of rubber and steel cord and a tire, which include the steel cord, are provided. A steel cord has a multi-twist structure in which N (N = 2 to 8) strands 2 are twisted, each strand 2 being formed by twisting a plurality of element wires 1 and having a substantially elliptical cross-section, wherein d1/d2 > 1.08 is satisfied, where the major diameter of the strand 2 is represented by d1 and the minor diameter is represented by d2, and µ c defined by the following equation: õ c = ˆš �¢ - b / 2 + ˆš �¢ b 2 / 4 - c - 1
(in the equation, b represents -1 + À 2 (-4R 2 + d 2 )/P 2 , c represents À 2 d 2 k(4À 2 R 2 + P 2 )/P 4 , R represents (D - d)/2, k represents tan 2 (À/2 - À/N), and d represents (d1 + d2)/2) satisfies µ c > 0.005, where the diameter of a circle circumscribing the cord is represented by D (mm) and the twist pitch of the cord is represented by P (mm).
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