Attachment structure for coil devices and coil device

1. An attachment structure for a coil device which attaches a flat coil device including a coil portion to an attachment portion, the attachment structure comprising:

a cylindrical holding portion provided in the attachment portion to hold the coil device;

a cylindrical engaged portion provided in the coil device and engaged with the holding portion, and

a positioning portion configured to define a selected coil alignment position of the coil device in a rotation direction whereat a predetermined directivity of magnetic flux with respect to the coil portion is achieved and to fix the rotated coil device at the coil alignment position,

wherein the holding portion and the engaged portion are disposed along an axis extending in a thickness direction of the coil device, and the engaged portion is engaged over the entire circumference thereof with the holding portion;

wherein a screw thread portion is provided on a peripheral surface of the holding portion and on a peripheral surface of the engaged portion, respectively, and

the coil device is fixed to the attachment portion by the engaged portion being screwed into the holding portion by rotation of the coil device around the axis; wherein:

the positioning portion has a first positioning portion provided in the attachment portion and a corresponding second positioning portion provided in the coil device;

the first positioning portion and corresponding second positioning portion being of the form of:

a first mark and a corresponding second mark,

a grove and corresponding push block,

an alignment hole and corresponding alignment hole, or

a magnet and corresponding magnet,

the coil device has a target position in the rotation direction corresponding to the selected coil alignment position, and

the coil device is positionally fixed at the target position to the attachment portion such that the first positioning portion aligns with the second positioning portion whereby the coil device is in the coil alignment position.

2. The attachment structure according to claim 1 ,

wherein the holding portion is provided in a region recessed from an end surface of the attachment portion in a direction of the axis, and

a portion or a whole of the coil device in a thickness direction is buried inside the attachment portion.

3. The attachment structure according to claim 2 , wherein the holding portion with which the engaged portion is engaged, and a housing accommodation portion which has a larger diameter than a diameter of the holding portion and accommodates a portion or a whole of a housing of the coil device are provided in the attachment portion.

4. The attachment structure according to claim 3 ,

wherein a side of the coil portion accommodated in the housing is separated from an inner side of the housing by a first annular gap in a direction orthogonal to the axis,

wherein an outer side of the housing is separated from a peripheral surface of the housing accommodation portion in the orthogonal direction by an annular second gap, and

the first gap is larger than the second gap.

5. The attachment structure according to claim 4 , wherein the housing accommodation portion is made of a magnetic member.

6. An electric vehicle comprising the attachment structure according to claim 1 mounted on an underside of the vehicle as part of a power receiver.

7. A power transmitter configured for disposition at a selected location over which an electric vehicle can be disposed for power reception comprising the attachment structure according to claim 1 .

8. The attachment structure according to claim 1 , wherein the first positioning portion and corresponding second positioning portion are of the form of a first mark and a corresponding second mark such that the coil device is positionally fixed to the attachment portion with a predetermined torque at which the first mark aligns with the second mark.

9. The attachment structure according to claim 1 , wherein the first positioning portion and corresponding second positioning portion are of the form of a grove and corresponding push block such that the coil device is positionally fixed to the attachment portion by engagement of the push block within the groove.

10. The attachment structure according to claim 1 , wherein the first positioning portion and corresponding second positioning portion are of the form of an alignment hole and corresponding alignment hole such that the coil device is positionally fixed to the attachment portion by a locking screw that engages both alignment holes.

11. The attachment structure according to claim 1 , wherein the first positioning portion and corresponding second positioning portion are of the form of a magnet and corresponding magnet such that the coil device is positionally fixed to the attachment portion by a magnetic field between the magnets.