COIL UNIT, AND POWER TRANSMISSION DEVICE, POWER RECEPTION DEVICE, AND WIRELESS POWER TRANSMISSION SYSTEM USING COIL UNIT

To reduce a leakage magnetic flux that largely goes around a region separated from an opposed coil while suppressing shielding of a main magnetic flux contributing to power transmission.SOLUTION: A coil unit 10 comprises: a coil 11 obtained by winding a lead wire in a spiral shape; a magnetic body 13 arranged at one end side in a coil axis direction of the coil 11; a first metal shield 14 arranged at an opposite side to an opposed surface to the coil, of the magnetic body 13; and a second metal shield 15 arranged so as to cover the circumference of the coil 11. In a region between an end part of the magnetic body 13 and the second metal shield 15, the first metal shield 14 is arranged so as to be separated from a reference plane SS including a surface at an opposite side to the opposed surface to the coil 11, of the magnetic body 13, in the coil axis direction. A length Lp of a projection of the second metal shield 15 that is protruded frontward in the coil axis direction of the coil 11 from the magnetic body 13, is shorter than a first distance Ly from the end part of the magnetic body 13 to the second metal shield 15.SELECTED DRAWING: Figure 2 【課題】電力伝送に寄与する主磁束の遮蔽を抑制しつつ、対向するコイルから離れた領域を大きく周回する漏洩磁束を低減する。【解決手段】コイルユニット１０は、導線が渦巻き状に巻回されたコイル１１と、コイル１１のコイル軸方向の一端側に配置される磁性体１３と、磁性体１３の前記コイルとの対向面とは反対側に配置される第１金属シールド１４と、コイル１１の周囲を覆うように配置される第２金属シールド１５とを備えている。磁性体１３の端部と第２金属シールド１５との間の領域において、第１金属シールド１４は、磁性体１３のコイル１１との対向面とは反対側の面を含む基準平面ＳＳからコイル軸方向に離間して配置されている。磁性体１３よりもコイル１１のコイル軸方向の前方に突出する第２金属シールド１５の突出部分の長さＬｐは、磁性体１３の端部から第２金属シールド１５までの第１の距離Ｌｙよりも短い。【選択図】図２