ROTOR OF ELECTRIC MOTOR

To provide a rotor of an electric motor in which a plurality of slots is open in a portion close to an outer circumference, permanent magnets 3 are inserted in the respective slots, a sectional shape of each of the slots in a direction orthogonal to the axis direction has a radially outer side that has a circumferential direction length longer than the circumferential direction length of a radially inner side, and is a line symmetric rectangular having four R-shaped corners, and a sectional shape of each of the permanent magnets 3 in a radial direction has four R-shaped corners C5, C6, C7, and C8 such that stress applied onto the portion in which the slots are open and toward a radially outer side is reduced to obtain a magnetic characteristic and mechanical durability simultaneously.SOLUTION: A curvature radius of two R portions, of each slot, that are positioned on a radially outer side is larger than a curvature radius of two R portions, of a permanent magnet 3, that are positioned on a radially outer side. Each of the R portions, of the permanent magnet 3, that are positioned on the radially outer side is inscribed inside a part of the corresponding R portion, of the slot, that is positioned on the radially outer side.SELECTED DRAWING: Figure 3 【課題】外周寄り部分に、スロットが複数開設され、各スロットに永久磁石３が内挿され、各スロットの軸方向に直交する方向の断面形状は、径方向外側の辺の周方向長さが径方向内側の辺の周方向長さよりも長い、線対称な四角形の４つの角部がＲ状に形成された形状であり、永久磁石３の径方向の断面形状は、４つの角部Ｃ５，Ｃ６，Ｃ７，Ｃ８がＲ状に形成された形状である電動機の回転子において、各スロットが開設された部分に加わる、径方向外方に向かう応力を低減させて磁気特性と機械的耐久性との両立を図る。【解決手段】各スロットの少なくとも径方向外側に位置する２つのＲ部の曲率が、径方向外側に位置する永久磁石３の２つのＲ部の曲率よりも大きく、永久磁石３の径方向外側に位置する各Ｒ部が、各スロットの径方向外側に位置する各Ｒ部の一部に内接する。【選択図】図３