Current sensor and measurement device

1. A current sensor configured to detect electric current flowing through an object to be measured in a state where the current sensor encloses the object to be measured, the current sensor comprising:

a coil body configured to detect the electric current flowing through the object to be measured; and

a holding portion to which a base end portion of the coil body is attached, the holding portion being configured to insert and hold a leading end of a leading end portion of the coil body in an insertion port of the holding portion, wherein

the leading end portion having the leading end of the coil body has a first shape in which a part, having a curvature greater than a curvature of the base end portion, is formed, and

the coil body has elasticity so that the leading end portion is restored from a second shape to the first shape or a shape close to the first shape when external force applied to the coil body is removed.

2. The current sensor according to claim 1 , wherein

the leading end portion of the coil body is formed to have a curvature greater than a curvature of the coil body in a state where the leading end of the coil body is held by the holding portion.

3. The current sensor according to claim 1 , wherein

the coil body is curved in such a manner that a tangent line of the base end portion of the coil body is orthogonal to a tangent line of an intermediate portion of the coil body.

4. The current sensor according to claim 1 , wherein

the base end portion of the coil body is formed in a linear shape.

5. The current sensor according to claim 1 , wherein

in the coil body, the curvature of the coil body is gradually increased from the base end portion to the leading end portion.

6. The current sensor according to claim 1 , wherein

a diameter of the coil body is equal to or smaller than 2 mm.

7. A measurement device, comprising:

the current sensor according to claim 1 ; and

a measurement portion configured to measure a physical amount of the object to be measured based on a detection signal outputted by the current sensor.

8. The current sensor according to claim 1 , wherein the coil body is restored to the first shape when the external force applied to the coil body is removed.

9. The current sensor according to claim 1 , wherein the coil body has flexibility so as to be warped from the first shape to the second shape when the external force is applied to the coil body.

10. A current sensor configured to detect electric current flowing through an object to be measured, the current sensor comprising:

a coil body configured to detect the electric current flowing through the object to be measured, wherein a leading end portion of the coil body has an original shape having a curvature greater than a curvature of a base end portion of the coil body; and

a holding portion attached to the base end portion of the coil body, the holding portion including an insertion port configured to releasably receive and hold the leading end portion of the coil body so that the original shape of the leading end portion is warped to a warped shape, wherein the holding portion is configured to release the leading end portion when an external force is applied to the coil body, and

wherein the coil body has elasticity to be restored to the original shape or a substantially similar shape to the original shape in response to the external force being removed from the coil body.

11. The current sensor according to claim 10 , wherein the coil body is restored to the original shape when the external force applied to the coil body is removed.