Patent ID: 6927525

Claim:
A unit core of a motor comprising a unit yoke that extends in a circumferential direction and a tooth radially protruding from the unit yoke, a plurality of said unit cores being interconnected so as to form a core of the motor, wherein the unit yoke has an elongated end extending from a central line connecting a center of the tooth to a center of the core in a predetermined direction, and a distance from a first edge of the elongated end of the yoke to said central line is greater than a distance from an opposite edge of the yoke to said center line, said edges extending transversely with respect to said predetermined direction and being adjacent to a surface of said elongated end that extends between said edges and wherein an angle from the central line, connecting the center of the tooth to the center of the core, to the elongated end has a value of θ r,max determined by: θ r , max = θ sy - sin - 1 ⁡ ( SOR × sin ⁡ ( θ ⁢ st / 2 ) SIR + YL ) , wherein, θ sy is an angle between both terminal points of the unit yoke centering on the center of the core, SOR is an outer diameter of the core, θ st is an angle between both terminals of an enlarged part of the tooth, and SIR is an inner diameter of the core, and YL is a radial width of the unit yoke.