Patent ID: 6703745
Filing Date: 2004-03-09
Classification: H02K

Abstract:
A rotor structure for a motor having built-in type permanent magnets comprising:a plurality of axial magnet slots for containing permanent magnets; a plurality of petal-shaped convex polar portions, each being disposed adjacent a corresponding one of the magnet slots and having an exterior circular arc on an outer side of the corresponding magnet slot; a shaft hole for installing a shaft; and a plurality of axial empty slots, each axial empty slot being provided between the shaft hole and a corner where a pair of adjacent magnet slots approach and having a sharp slot vertex formed at the corner where the pair of adjacent magnet slots approach, each axial empty slot additionally having extended slot sides formed on opposite sides of the slot in between the slot vertex and a slot bottom, wherein the center of the petal-shaped convex polar portion the center of the exterior circular arc and the center of the rotor are spaced apart by a position difference R2 such that the radius R1 of the exterior circular arc is smaller than the radius R of the rotor in accordance with the relation R1+R2=R, and the circular arc is eccentric from the center of the rotor.