Patent ID: 7518277
Filing Date: 2009-04-14
Classification: H02K

Abstract:
1. An electric motor comprising a rotor equipped with magnets and a stator having a plurality of slots, wherein: said rotor or said stator is divided into four pieces of a first piece, a second piece, a third piece and a fourth piece in an axial direction, and an axial length and an electrical angle of said each piece, assuming an axial length of said four pieces of said rotor core or said stator core as 2L, with L being an axial length dimension, said axial direction as a X-axis, an axial center as x=0, and electromagnetic exciting force in a radial direction as F(x), on the basis of following three relational formulas: are set according to a relationship between an equivalent axial length and an equivalent position shifted between said pieces in a circumferential direction and are arranged in a setting order, and a length of said first piece in said axial direction is from 0.19L to 0.39L, a length of said second piece in said axial direction is from 0.81L to 0.61L, a length of said third piece in said axial direction is from 0.81L to 0.61L, and a length of said fourth piece in said axial direction is from 0.19L to 0.39L, and effective pole opening angles are arranged in a circumferential direction as phase difference of electrical angles of said neighboring pieces equivalent to 0, π, 0, and π.