| 摘要 |
PROBLEM TO BE SOLVED: To suppress the occurrence of eddy currents by forming each rear-earth permanent magnet attached to one pole of the outer peripheral section of a rotor core so that the magnet may have a trapezoidal cross section in the axial direction. SOLUTION: The magnets of one pole is composed of rectangular permanent magnets 1a-1n which are electrically insulated from each other. The eddy currents which occur in a rotor core 2 concentrate to the surface of a rotor and are discriminated from the penetrating depth of a high-frequency current when the rotor is made of a metal. When the frequency of the current becomes higher and the relative permeability of the rotor becomes larger, the penetrating depth becomes shallower. When the magnet of a rotary electric machine is fractionated and the fractionated magnets are electrically insulated from each other, the routes of eddy currents can be cut off. Therefore, when the magnet is divided in the axial direction or the angular direction of the axial cross section and the divided magnets are insulated from each other, a permanent-magnet rotor which hardly generates eddy currents can be obtained. Each rare-earth permanent magnet is composed of, for example, an Nd-Fe-B permanent magnet, electrically insulated by coating the magnet with epoxy paint, etc., and layered so as to suppress the occurrence of eddy currents.
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