| 摘要 |
A coil structure used for an endoscope (1) is provided with: a coil tube (33) having affixed opposite ends; a wire material (40) densely wound to form the coil tube (33); a first contact surface (41) formed on one surface of the metallic wire (40), said surface being located on the distal end side; and a second contact surface (42) formed on the other surface of the metallic wire (40), said the other surface being located on the proximal end side, the second contact surface (42) allowing the first contact surface (41) to come into contact therewith. The first contact surface (41) is formed as a convex surface having a circular arc cross-sectional shape, the center (O1) of the curvature of which is located inside the outer peripheral section of the coil tube (33). The convex surface has a curvature radius (R1) larger than the radius (D/2) of the coil tube (33) and smaller than the curvature radius (SR) of an insertion section (2) in a maximally bent position. |
