Endoscope, endoscope system, and method of manufacturing endoscope

1. An endoscope for applying a propulsion force in a direction of insertion axis of an insertion portion in accordance with rotation of the insertion portion around the insertion axis based on a driving force of a driving member, the endoscope comprising:

a flexible elongated inner layer tube in which bending operation wires for bending a bending portion provided in the insertion portion, a signal cable of an image-pickup unit provided in the insertion portion, a power source cable for a light source provided in the insertion portion, and tubes for air feeding, water feeding and suction provided at the insertion portion are inserted, and which protects the wires, the cable and the tubes for air feeding, water feeding and suction configured as a shaft of the insertion portion;

a spiral-shaped portion rotatable around the inner layer tube as an axial center based on the driving force of the driving member, the spiral-shaped portion forming an outer surface of the insertion portion, and covering an outer circumference of the inner layer tube such that a clearance is formed between the spiral-shaped portion and the inner layer tube; and

a connection element having a first portion disposed on the flexible elongated inner layer tube and a second portion disposed on the spiral-shaped portion, the second portion being rotatably engaged with the first portion;

wherein, the spiral-shaped portion includes a nondensely wound metal coil and a resin thin film continuously provided so as to cover gaps of a wire forming the metal coil.

2. The endoscope according to claim 1 , wherein either an outer circumference or an inner circumference of the spiral-shaped portion is coated with the resin thin film.

3. The endoscope according to claim 2 , wherein at least a front half part of the metal coil in the direction of insertion axis of the insertion portion is coated with the resin thin film.

4. The endoscope according to claim 2 , wherein a surface treatment agent for improving lublicity is applied to the inner circumference of the metal coil and an inner circumference of the resin thin film.

5. The endoscope according to claim 2 , wherein a surface treatment agent for improving lublicity is applied to an outer circumference of the resin thin film.

6. The endoscope according to claim 1 , wherein the metal coil and the resin thin film is extendable in the direction of insertion axis of the insertion portion.

7. The endoscope according to claim 1 , wherein the wire is formed to have a diameter of from not less than 0.6 millimeters to not more than 2.0 millimeters.

8. The endoscope according to claim 1 , wherein the wire is wound at a lead angle of not less than 3 degrees to not more than 15 degrees.

9. The endoscope according to claim 1 , wherein the resin thin film has a hardness of not less than 50 degrees to not more than 90 degrees and formed to have a thickness of not less than 0.03 millimeters to not more than 0.20 millimeters.

10. An endoscope system comprising:

the endoscope according to claim 1 ; and

the driving member for moving and rotating the spiral-shaped portion of the endoscope about the insertion axis of the insertion portion such that the inner layer tube becomes an axial center.

11. An endoscope system comprising:

the endoscope according to claim 2 ; and

the driving member for moving and rotating the spiral-shaped portion of the endoscope about the insertion axis of the insertion portion such that the inner layer tube becomes an axial center.

12. The endoscope according to claim 1 , wherein there is formed a clearance between the spiral-shape portion and the inner layer tube such that the inner layer tube is not pressed even if the resin thin film protrudes inwardly when the metal coil is bent maximally.