Patent ID: 7105971
Filing Date: 2006-09-12
Classification: H02K

Abstract:
1. A magnet-saving type rotor for a synchronous motor comprising: a rotor core, and a total of k permanent magnets installed in said rotor core, each of said permanent magnets having a first polarity portion and a second polarity portion, wherein said rotor core comprises: a total of k magnet accommodation holes, formed in said rotor core closely to an outer cylindrical surface of said rotor core along a circumferential direction of said rotor core, which accommodate said permanent magnets, respectively, so as to direct the first polarity portions of said permanent magnets toward a radial outer side of said rotor core, each of said magnet accommodation holes extending in an axial direction of said rotor core, said magnet accommodation holes being disposed at equal angular pitches of θn equivalent to 360/k degrees, a total of 2 k magnet-less holes, respectively, formed at 2 k circumferential ends of said k magnet accommodation holes without accommodating said permanent magnets, each of said magnet-less holes extending in the axial direction of said rotor core; a total of k first magnetic pole portions positioned at a radial outer side of said magnet accommodation holes in an outer peripheral region of said rotor core along the circumferential direction of said rotor core and having a first polarity due to the first polarity portions of said permanent magnets; and a total of k second magnetic pole portions having a second polarity and positioned at the radial outer side of said rotor core along the circumferential direction of said rotor core, each of said second magnetic pole portions being positioned between two magnet-less holes closest to each other among four magnet-less holes corresponding to two magnet accommodation holes placed next to each other, wherein a sector angle occupied by each of said magnet-less holes positioned at both circumferential ends of respective magnet accommodation holes is equal to θ where θ