Coil, guide wire, and coil manufacturing method

1. A coil that is made by helically winding a wire rod,

wherein a cross-sectional shape of the wire rod includes:

a curved portion that is arcuately curved toward a center axis of the coil;

a flat portion that is provided on an outer circumference of the coil, and is formed in a flat shape with a curvature that is smaller than that of the curved portion; and

at least one protruding portion that is provided adjacent an end of the flat portion and protrudes from a convex surface of the curved portion toward a proximally adjacent wire rod, a convex surface of the protruding portion intersecting with convex surface of the curved portion to define a recess,

wherein in a no-load state in which an external force is not applied, only the convex surface of the protruding portion, including a proximalmost tip of the convex surface of the protruding portion, is in contact with the proximally adjacent wire rod, the convex surface of the curved portion is not in contact with the proximally adjacent wire rod, and the recess is not in contact with the proximally adjacent wire rod.

2. The coil according to claim 1 ,

wherein the convex surface of the protruding portion is curved with a curvature greater than that of the curved portion.

3. The coil according to claim 1 ,

wherein when an external force is applied such that contact pressure between adjacent wire rods increases, one wire rod of the adjacent wire rods moves upward relative to an other wire rod, and when the external force is reduced or released, due to the resilience of the one wire rod, the one wire rod returns to an original position thereof while the curved portion of the one wire rod slides against the protruding portion of the other wire rod.

4. The coil according to claim 2 ,

wherein when an external force is applied such that contact pressure between adjacent wire rods increases, one wire rod of the adjacent wire rods moves upward relative to an other wire rod, and when the external force is reduced or released, due to the resilience of the one wire rod, the one wire rod returns to an original position thereof while the curved portion of the one wire rod slides against the protruding portion of the other wire rod.

5. The coil according to claim 1 ,

wherein protruding portions are respectively provided adjacent both respective ends of the flat portion.

6. The coil according to claim 2 ,

wherein protruding portions are respectively provided adjacent both respective ends of the flat portion.

7. A guide wire comprising:

the coil according to claim 1 ; and

a wire main body that has flexibility,

wherein the wire main body is inserted into the coil.

8. The coil according to claim 1 , wherein, in the no-load state, the proximalmost tip of the convex surface of the protruding portion is in contact with a distal end portion of the convex surface of the curved portion of the proximally adjacent wire rod.

9. The coil according to claim 1 , wherein, a radius of curvature of the curved portion is greater than a radius of curvature of the protruding portion.

10. The coil according to claim 9 , wherein, in the no-load state, the proximalmost tip of the convex surface of the protruding portion is in contact with a distal end portion of the convex surface of the curved portion of the proximally adjacent wire rod.

11. The coil according to claim 1 , wherein, in the no-load state, the proximalmost tip of the convex surface of the protruding portion is in contact with a distalmost tip of a convex surface of a second protruding portion of the proximally adjacent wire rod.