Coil component and electronic circuit

1. A coil component comprising:

a columnar core including a shaft and a flange provided at one end of the shaft, a diameter of the flange being larger than a diameter of the shaft, an outer flange periphery of the flange having first and second flange peripheries;

a wire wound around the shaft forming a coil; and

an annular core including a housing and an opening provided in the housing, the columnar core being inserted into the housing of the annular core so that the opening is partially occupied by the flange in a plan view,

wherein the first flange periphery is overlapped with a first closest inner edge of the housing in a plan view, and

the second flange periphery is spaced apart from a second closest inner edge of the housing in the plan view.

2. The coil component according to claim 1 ,

wherein the outer flange periphery of the flange includes a plurality of pairs of first and second flange peripheries, and the plurality of pairs of first and second flange peripheries are sequentially provided at substantially equal intervals, and

a peripheral length of the first flange periphery is smaller than a peripheral length of the second flange periphery.

3. The coil component according to claim 1 ,

wherein the flange is in a nearly rectangular shape,

the opening is in a nearly circular shape, and

an inner diameter of the opening is larger than one side of the flange, and the inner diameter of the opening is shorter than a diagonal of the flange.

4. The coil component according to claim 1 ,

wherein the annular core has a recess formed on one face in which the opening is formed, and

the first flange periphery is fitted to the recess.

5. The coil component according to claim 4 ,

wherein the flange has an apex in an edge thereof, the apex is positioned in the first flange periphery,

the recess has a corner portion therein which corresponds to the shape of the apex, and

after the apex is fitted in the corner, relative movement between the columnar core and the annular core is limited.

6. The coil component according to claim 5 ,

wherein the outer flange periphery of the flange includes a plurality of pairs of first and second flange peripheries, and the recess further comprises a plurality of recesses including first and second recesses,

wherein a distance from an edge of one of the first flange peripheries to an inner wall of the first recess is smaller than a distance from an edge of another of the first flange peripheries to an inner wall of the second recess, and

the one of the first flange peripheries has the apex, and the another of the first flange peripheries is spaced apart from the apex.

7. The coil component according to claim 3 ,

wherein the annular core has a top face having the opening provided therein, and a bottom face positioned opposite to the top face,

the housing extends through the annular core from the top face to the bottom face so that the opening is a through hole provided in the housing,

the bottom face includes a mounting face which is brought into contact with a board after the coil component is mounted on the board, and the bottom face includes an offset face which is spaced apart from the board, and

part of the offset face is positioned immediately under a gap between an inner face of the opening and an edge of the second flange periphery in the plan view.

8. The coil component according to claim 7 ,

wherein another part of the offset face is positioned immediately under the first flange periphery in the plan view, and

a round-bottom trench is formed in the housing, and the round-bottom trench is continuously formed with the another part of the offset face.

9. The coil component according to claim 3 ,

wherein another flange is formed at the other end of the shaft opposite to the one end of the shaft, and

the another flange has a plurality of notches, one of the notches is cut deeper than the other of the notches.

10. The coil component according to claim 7 ,

wherein another flange is formed at the other end of the shaft opposite to the one end of the shaft, and

the another flange has a plurality of notches, one of the notches is cut deeper than the other of the notches.

11. The coil component according to claim 10 ,

wherein the mounting face is plated, and

an end of the wire drawn out through one of the notches is electrically connected to the mounting face.

12. An electronic circuit comprising:

the coil component of claim 1 ;

an electronic component mounted on a board together with the coil component; and

a resin encapsulating the coil component.

13. The electronic circuit according to claim 12 ,

wherein the coil component and the electronic component are encapsulated together with the resin.

14. A coil component comprising:

a columnar core having a shaft, the shaft having a coil wound therearound, the columnar core having a flange formed at least at one end of the shaft, a diameter of the flange being larger than a diameter of the shaft; and

an annular core having an opening through which the columnar core is inserted, the annular core having a housing which houses the columnar core inserted through the opening,

wherein a perimeter of an inner flange face of the flange includes an externally disposed region which is located radially outside an inner face of the opening and an internally disposed region which is located radially inside the inner face of the opening,

wherein the annular core has a recess in one face in which the opening is formed,

the externally disposed region is fitted to the recess,

wherein the flange has an apex in an edge thereof, the apex is located in the externally disposed region,

the recess has a corner which corresponds to the shape of the apex, and

after the apex is fitted in the corner, relative movement between the columnar core and the annular core is limited.

15. The coil component according to claim 14 ,

wherein the externally disposed region further comprises a plurality of externally disposed regions including first and second externally disposed regions, and the recess further comprises a plurality or recesses including first and second recesses,

wherein a distance from the perimeter of the flange to an inner wall of the first recess in the first externally disposed region is smaller than a distance from the perimeter of the flange to an inner wall of the second recess in the second externally disposed region, and

the first externally disposed region has the apex, and the second externally disposed region is spaced apart from the apex.

16. A coil component comprising:

a columnar core having a shaft, the shaft having a coil wound therearound, the columnar core having a flange formed at one end of the shaft, a diameter of the flange being larger than a diameter of the shaft; and

an annular core having an opening through which the columnar core is inserted, the annular core having a housing which houses the columnar core inserted through the opening,

wherein a perimeter of an inner flange face of the flange includes an externally disposed region which is located radially outside an inner face of the opening and an internally disposed region which is located radially inside the inner face of the opening,

wherein the flange is in a nearly rectangular shape,

the opening is in a nearly circular shape,

an inner diameter of the opening is larger than one side of the flange, and the inner diameter of the opening is shorter than a diagonal of the flange,

wherein another flange is formed at the other end of the shaft opposite to the one end of the shaft, and

the another flange has a plurality of notches, and one of the notches is cut deeper than the other of the notches.