Overhead wire

An overhead cable comprising:

• a tension-bearing core;
• a conductive layer formed at the outer circumference of said core;
• and
• an outermost layer formed by twisting together a plurality of segment strands at an outer circumference of said conductive layer,
• said segment strands forming the outermost layer including thin segment strands and at least one thick segment strand and
• the following condition being satisfied:
• 0.01<H/D<0.10 and
• 10°<θ<90°
• where a step difference between an outer circumferential surface of said thin segment strands and an outer circumferential surface of said thick segment strands in the state where they are twisted together to form the outermost layer is H, a center angle of said thick segment strands is θ, and an outer diameter of the overhead cable demarcated by said thin segment strands is D,
• wherein said outermost layer formed by said plurality of segment strands has at a part of an outer circumferential surface of said segment strands or outer circumferential surface regions of boundary portions where said segment strands are twisted together to adjoin each other at either one groove or a plurality of grooves that form a spiral shape along an outer surface of said outermost layer, each groove including a first surface opposite from and substantially parallel to a second surface and a bottom portion with a rectangular cross-section formed there between at intervals in the circumferential direction of the overhead cable,
• wherein said outermost layer formed by said plurality of segment strands has at a part of an outer circumferential surface of said segment strands or outer circumferential surface regions of boundary portions where said segment strands are twisted together to adjoin each other at either one groove or a plurality of grooves that form a spiral shape along an outer surface of said outermost layer, each groove including a first surface opposite from and substantially parallel to a second surface and a bottom portion with a rectangular cross-section formed there between at intervals in the circumferential direction of the overhead cable and
• said spiral grooves are formed to satisfy 1<W/h<16 where a width and a depth of said cross-section are W and h.

An overhead cable comprising:

• a tension-bearing core;
• a conductive layer formed at the outer circumference of said core;
• and
• an outermost layer formed by twisting together a plurality of segment strands at an outer circumference of said conductive layer,
• said segment strands forming the outermost layer including thin segment strands and at least one thick segment strand and
• the following condition being satisfied:
• 0.01<H/D<0.10 and
• 10°<θ<90°
• where a step difference between an outer circumferential surface of said thin segment strands and an outer circumferential surface of said thick segment strands in the state where they are twisted together to form the outermost layer is H, a center angle of said thick segment strands is θ, and an outer diameter of the overhead cable demarcated by said thin segment strands is D,
• wherein said outermost layer formed by said plurality of segment strands has at a part of an outer circumferential surface of said segment strands or outer circumferential surface regions of boundary portions where said segment strands are twisted together to adjoin each other at either one groove or a plurality of grooves that form a spiral shape along an outer surface of said outermost layer, each groove including a first surface opposite from and substantially parallel to a second surface and a bottom portion with a rectangular cross-section formed there between at intervals in the circumferential direction of the overhead cable,
• wherein said outermost layer formed by said plurality of segment strands has at a part of an outer circumferential surface of said segment strands or outer circumferential surface regions of boundary portions where said segment strands are twisted together to adjoin each other at either one groove or a plurality of grooves that form a spiral shape along an outer surface of said outermost layer, each groove including bottom portion with a rectangular cross-section formed there between at intervals in the circumferential direction of the overhead cable and
• said spiral grooves have at their two edge portions a chamfer of a gradient of 10% or less or a chamfer of a radius of curvature of ½ or less of a diameter of said overhead cable.

An overhead cable comprising:

• a tension-bearing core;
• a conductive layer provided at an outer circumference of said core;
• and
• an outermost layer formed by twisting a plurality of segment strands at an outer circumference of said conductive layer,
• each of said plurality of segment strands forming the outermost layer having a recessed portion formed at one side surface among a pair of side surfaces facing each other in a circumferential direction of the overhead cable and a projecting portion formed at the other side surface so as to mate with an adjacent segment strand in the twisted state,
• wherein the following condition is satisfied:
• 0.2T≦G≦0.8T (mm)
• where the distance from a center portion of a bottom of the recessed portion and a center portion of a top of said projecting portion to a bottom surface of said segment strands is G and a thickness from a bottom surface to a circumferential surface of said segment strand is T.

An overhead cable comprising:

• a tension-bearing core;
• a conductive layer provided at an outer circumference of said core;
• and
• an outermost layer formed by twisting together a plurality of segment strands at an outer circumference of said conductive layer,
• each of said plurality of segment strands forming the outermost layer having a recessed portion formed at one side surface among a pair of side surfaces facing each other in a circumferential direction of the overhead cable and a projecting portion formed at the other side surface so as to mate with an adjacent segment strand in the twisted state and
• a length of contact in an overhead cable diametrical direction of recessed and projecting surfaces of at least one recess-projection mating portion among a plurality of recess-projection mating portions in a state where the projecting portions are mated with the recessed portions being made not more than 10% of an entire length in said diametrical direction of said recess-projection mating portion,
• wherein said projecting portion has a top arc surface portion where the top forms an arc surface of a radius of curvature R1, said recessed portion has a bottom arc surface portion where the bottom forms an arc surface of a radius of curvature R2, and said radius of curvature R1 and said radius of curvature R2 satisfy R1>R2.