Provided is a multi-twisted steel cord for reinforcing a rubber article, the steel cord having cord strength with a small loss as compared to the total strength of filaments constituting the cord and a high rubber penetration. The steel cord includes a plurality of twisted strands in a multi-twisted structure, each strand including a plurality of twisted filaments in two or more layers, in which at least some of the filaments have a tensile strength of 3,000 MPa or more, the steel cord satisfying a filament occupancy of 48% or more and less than 54%, a cord twist angle of 78 or more and less than 84, an average crossing angle between adjacent filaments other than wrapping filaments of less than 17, and a gap between adjacent sheath filaments constituting the strand of 0.065 mm or more.

Provided is a multi-twisted steel cord for reinforcing a rubber article, the steel cord having cord strength with a small loss as compared to the total strength of filaments constituting the cord and a high rubber penetration. The steel cord includes a plurality of twisted strands in a multi-twisted structure, each strand including a plurality of twisted filaments in two or more layers, in which at least some of the filaments have a tensile strength of 3,000 MPa or more, the steel cord satisfying a filament occupancy of 48% or more and less than 54%, a cord twist angle of 78 or more and less than 84, an average crossing angle between adjacent filaments other than wrapping filaments of less than 17, and a gap between adjacent sheath filaments constituting the strand of 0.065 mm or more.

Provided are: a cable bead which can realize a weight reduction while maintaining the breaking pressure resistance; and an airplane tire including the same. A cable bead (10) includes: a core (1) composed of an annularly formed steel; and a sheath (3) composed of at least one sheath layer, which is formed by spirally winding a sheath filament (2) composed of a steel around the core (1). The sheath filament (2) has a carbon content of higher than 0.90% by mass but 0.95% by mass or less, and a chromium content of 0.15 to 0.30% by mass.

Provided are: a cable bead which can realize a weight reduction while maintaining the breaking pressure resistance; and an airplane tire including the same. A cable bead (10) includes: a core (1) composed of an annularly formed steel; and a sheath (3) composed of at least one sheath layer, which is formed by spirally winding a sheath filament (2) composed of a steel around the core (1). The sheath filament (2) has a carbon content of higher than 0.90% by mass but 0.95% by mass or less, and a chromium content of 0.15 to 0.30% by mass.

A compact steel cord is provided. The cord includes a core-filament I steel wire with a diameter of d0, and four middle-layer M steel wires with a diameter of d1 and eight outer-layer O steel wires with a diameter of d2 that are twisted around the core-filament I steel wire in the same lay direction and the same lay length. Gaps L are reserved between the outer-layer O steel wires, an average width of the gaps L is not smaller than 0.02 mm, and the total size of the gaps L is larger than d0 and smaller than d1. The steel cord of a stable structure can be obtained by controlling the proportion of the sizes of all layers of monofilaments, the rubber coating performance of a tire cord can also be improved, the corrosion resistance, fatigue resistance, impact resistance and adhesion retention of a tire are improved.

A steel cord and a manufacturing process are disclosed. The steel cord includes a steel core wire located in the center and having a diameter of d; and M sheath-layer steel wires arranged around the steel core wire in the center, tangent to the steel core wire, and having a diameter of d1, at least two gaps L existing between the M sheath-layer steel wires, where M is 4; d, d1, and L satisfy the following relationship: 0.420<(d/d1)<0.800, d1 is between 0.20 mm and 0.44 mm, and L0.0008 mm. The steel cord of the present invention may allow rubber to be fully penetrated into the gaps, thereby reducing air content in the steel cord, avoiding point contact friction between the layers of steel wires due to insufficient rubber penetration, and further solving the problem of failure of the bearing capacity of the steel cord due to abrasion.

A steel cord and a manufacturing process are disclosed. The steel cord includes a steel core wire located in the center and having a diameter of d; and M sheath-layer steel wires arranged around the steel core wire in the center, tangent to the steel core wire, and having a diameter of d1, at least two gaps L existing between the M sheath-layer steel wires, where M is 4; d, d1, and L satisfy the following relationship: 0.420<(d/d1)<0.800, d1 is between 0.20 mm and 0.44 mm, and L0.0008 mm. The steel cord of the present invention may allow rubber to be fully penetrated into the gaps, thereby reducing air content in the steel cord, avoiding point contact friction between the layers of steel wires due to insufficient rubber penetration, and further solving the problem of failure of the bearing capacity of the steel cord due to abrasion.

A steel cord for reinforcing a breaker or belt ply in a rubber tire having a core group and a sheath group. The core group consists of two to four core steel filaments with a first diameter dc and the sheath group consists of one to six sheath steel filaments with a second diameter ds. The ratio dc/ds of the first diameter dc to the second diameter ds ranges from 1.10 to 1.70. The two core steel filaments are untwisted or have a twisting step greater than 300 mm. The sheath group is twisted around the core group with a cord twisting step in a cord twisting direction. The ratio of the difference in residual torsions of the core group and the sheath group to the difference in saturation level between the core group and the sheath group ranges from 0.10 to 0.65, preferably from 0.10 to 0.60.

A steel cord for reinforcing a breaker or belt ply in a rubber tire having a core group and a sheath group. The core group consists of two to four core steel filaments with a first diameter dc and the sheath group consists of one to six sheath steel filaments with a second diameter ds. The ratio dc/ds of the first diameter dc to the second diameter ds ranges from 1.10 to 1.70. The two core steel filaments are untwisted or have a twisting step greater than 300 mm. The sheath group is twisted around the core group with a cord twisting step in a cord twisting direction. The ratio of the difference in residual torsions of the core group and the sheath group to the difference in saturation level between the core group and the sheath group ranges from 0.10 to 0.65, preferably from 0.10 to 0.60.

The present invention relates to a rope for an elevator. The rope for the elevator comprises: a center strand formed by twisting a plurality of wires; inner layer strands formed by twisting the plurality of wires and arranged along the outer periphery of the center strand; and outer layer strands formed by twisting the plurality of wires and arranged along the outer periphery of the inner layer strands, wherein ten of each of the inner layer strands and the outer layer strands are prepared, the diameter of the center strand, the diameter of the inner layer strand and the diameter of the outer layer strand are respectively 0.33-0.35 times, 0.13-0.15 times and 0.22-0.24 times as large as the diameter of a first imaginary circle circumscribed around the outer layer strands, and a fill factor is 64-67%.