Patent ID: 6140736
Filing Date: 2000-10-31
Classification: H02K

Abstract:
An outer rotor means, adapted for an outer-rotor electric motor, comprising:a cylinder member (31) having a plurality of recesses (312) radially recessed in an inside wall of said cylinder member (31);a magnetic conductor (30) concentrically secured in said cylinder member (31), and having an inner hole (301) rotatably engageable with an inner stator about an axis (X), and having a plurality of protrusions (303) radially protruding outwardly from an outer peripheral surface (302) of said magnetic conductor (30), with each said protrusion (303) engaged with each said recess (312) for firmly coupling said magnetic conductor (30) in said cylinder member (31) for preventing loosening of said magnetic conductor (30) from said cylinder member (31) when rotated; andan end plate (32) secured to an end portion of said cylinder member (31);said magnetic conductor (30) formed as an annular magnet ring having a plurality of magnetic poles radially divided in the annular magnet ring about the axis (X), each magnetic pole corresponding to a magnetic-pole central angle (.theta.), whereby when the number of said magnetic poles in said magnetic conductor (30) is designated as n, each said magnetic-pole central angle (.theta.) is obtained as: 360.degree./n; each said recess (312) formed as an arcuate recess (312) in said cylinder member (31) having a chord (C) across the arcuate recess (312) defining a central angle (A) between the chord (C) and the axis (X); andeach said protrusion (303) formed as an arcuate protrusion (303) on said magnetic conductor (30) having a chord (C), the same as the chord (C) of said arcuate recess (312), across the arcuate protrusion (303) defining said central angle (A) between said chord (C) and said axis (X).