ELECTRIC MOTOR AND FIELD MAGNETON

To provide an electric motor with a bond magnet which is effective for reduction of eddy current loss.SOLUTION: The present invention is an electric motor with: an armature; a field magneton which uses a permanent magnet as a magnetic force source; and a rotational axis which rotates with the armature or the field magneton. The permanent magnet is a bond magnet consisting of magnet particles and binder resin binding the magnet particles. In the bond magnet, electric resistance anisotropy (ρ1/ρ2) which is ratio between first electric resistivity (ρ1) measured in an axial direction and second electric resistivity (ρ2) measured in a direction perpendicular to the axial direction is equal to or more than 2. The bond magnet is a compression molding bond magnet containing, for example, 93 to 98.5% of the magnet particles, and its first electric resistivity becomes equal to or more than 300 μΩm. When the compression molding bond magnet formed by arranging a compression direction along the axial direction is used as a field source, eddy current loss to be generated in the compression molding bond magnet can be efficiently reduced.SELECTED DRAWING: Figure 2 【課題】本発明は、渦電流損の低減に有効なボンド磁石を備えた電動機を提供する。【解決手段】本発明は、電機子と、永久磁石を磁力源とする界磁子と、電機子または界磁子と共に回転する回転軸とを備える電動機である。永久磁石は、磁石粒子と磁石粒子同士を結着するバインダ樹脂とからなるボンド磁石である。ボンド磁石は、軸方向に測定した第１電気抵抗率（ρ１）と軸方向に垂直な方向に測定した第２電気抵抗率（ρ２）との比率である電気抵抗異方度（ρ１／ρ２）が２以上である。ボンド磁石は、例えば、磁石粒子を９３〜９８．５％含む圧縮成形ボンド磁石であり、その第１電気抵抗率は３００μΩｍ以上となる。圧縮方向を軸方向に沿って配設した圧縮成形ボンド磁石を界磁源として用いると、その圧縮成形ボンド磁石に生じる渦電流損を効率的に低減できる。【選択図】図２