Coil unit, and power transmitting device, power receiving device and wireless power transmission system using the coil unit
Disclosed herein is a coil unit that includes a coil formed by spirally winding a conductive wire, a capacitor electrically connected to the coil, a magnetic member covering the coil in an axial direction of the coil, a first metal shield covering the coil with the magnetic member interposed therebetween, and a second metal shield disposed between the magnetic member and the first metal shield so as to form a space for housing the capacitor. The second metal shield is disposed so as to be thermally connected to the first metal shield. An outer dimension of the second metal shield as viewed in the axial direction of the coil is equal to or smaller than an outer dimension of the magnetic member.
1. A coil unit comprising:
a coil formed by spirally winding a conductive wire;
a capacitor electrically connected to the coil;
a magnetic member covering the coil in an axial direction of the coil;
a first metal shield covering the coil with the magnetic member interposed therebetween; and
a second metal shield disposed between the magnetic member and the first metal shield so as to form a space for housing the capacitor,
wherein a surface of the capacitor that is closest to the coil in the axial direction of the coil is located farther from the coil than the magnetic member;
wherein the second metal shield is disposed so as to be thermally connected to the first metal shield, and
wherein an outer dimension of the second metal shield as viewed in the axial direction of the coil is equal to or smaller than an outer dimension of the magnetic member.
2. The coil unit as claimed in claim 1 , wherein the second metal shield is disposed so as to be thermally connected to the magnetic member.
3. The coil unit as claimed in claim 1 , wherein the second metal shield includes a flat plate part facing to the magnetic member and a side wall connected to the flat plate part and disposed around the capacitor.
4. The coil unit as claimed in claim 3 , wherein a leading end portion of the side wall directed from the flat plate part to the first metal shield is arranged opposite to a main surface of the first metal shield.
5. The coil unit as claimed in claim 3 , wherein an opening is formed in a part of the side wall, through which a power cable connected to the coil or capacitor is drawn outside.
6. The coil unit as claimed in claim 5 ,
wherein the second metal shield has a planar shape elongated in one direction as viewed in the axial direction of the coil,
wherein the coil axis extends in substantially a horizontal direction, and
wherein the opening is formed on one end side of the second metal shield in a longitudinal direction thereof.
7. The coil unit as claimed in claim 3 ,
wherein the second metal shield further includes a flange part formed by bending a leading end portion of the side wall inward or outward, and
wherein the flange part is thermally connected to a main surface of the first metal shield.
8. The coil unit as claimed in claim 7 ,
wherein the second metal shield has a planar shape elongated in one direction as viewed in the axial direction of the coil, and
wherein the flange part is provided so as to extend in a longitudinal direction of the second metal shield.
9. The coil unit as claimed in claim 1 , wherein an outer dimension of the second metal shield as viewed in the axial direction of the coil is equal to or larger than an outer dimension of the coil.
10. The coil unit as claimed in claim 1 , wherein an outer dimension of the first metal shield as viewed in the axial direction of the coil is larger than an outer dimension of the second metal shield.
11. The coil unit as claimed in claim 1 , further comprising a heat sink provided on a rear side of the first metal shield opposite to a front side facing to the second metal shield.
12. A power transmitting device comprising:
a coil unit; and
an inverter circuit connected to the coil unit,
wherein the coil unit comprising:
a coil formed by spirally winding a conductive wire;
a capacitor electrically connected to the coil;
a magnetic member covering the coil in an axial direction of the coil;
a first metal shield covering the coil with the magnetic member interposed therebetween; and
a second metal shield disposed between the magnetic member and the first metal shield so as to form a space for housing the capacitor,
wherein a surface of the capacitor that is closest to the coil in the axial direction of the coil is located farther from the coil than the magnetic member;
wherein the second metal shield is disposed so as to be thermally connected to the first metal shield, and
wherein an outer dimension of the second metal shield as viewed in the axial direction of the coil is equal to or smaller than an outer dimension of the magnetic member.
13. A power receiving device comprising:
a coil unit; and
a rectifying circuit connected to the coil unit,
wherein the coil unit comprising:
a coil formed by spirally winding a conductive wire;
a capacitor electrically connected to the coil;
a magnetic member covering the coil in an axial direction of the coil;
a first metal shield covering the coil with the magnetic member interposed therebetween; and
a second metal shield disposed between the magnetic member and the first metal shield so as to form a space for housing the capacitor,
wherein a surface of the capacitor that is closest to the coil in the axial direction of the coil is located farther from the coil than the magnetic member;
wherein the second metal shield is disposed so as to be thermally connected to the first metal shield, and
wherein an outer dimension of the second metal shield as viewed in the axial direction of the coil is equal to or smaller than an outer dimension of the magnetic member.
14. A wireless power transmission system comprising:
a power transmitting device that transmits power by wireless; and
a power receiving device that receives the power from the power transmitting device by wireless,
wherein at least one of the power transmitting device and power receiving device includes a coil unit that comprises:
a coil formed by spirally winding a conductive wire;
a capacitor electrically connected to the coil;
a magnetic member covering the coil in an axial direction of the coil;
a first metal shield covering the coil with the magnetic member interposed therebetween; and
a second metal shield disposed between the magnetic member and the first metal shield so as to form a space for housing the capacitor,
wherein a surface of the capacitor that is closest to the coil in the axial direction of the coil is located farther from the coil than the magnetic member;
wherein the second metal shield is disposed so as to be thermally connected to the first metal shield, and
wherein an outer dimension of the second metal shield as viewed in the axial direction of the coil is equal to or smaller than an outer dimension of the magnetic member.