Patent ID: 7863793
Filing Date: 2011-01-04
Classification: H02K

Abstract:
1. A field element core comprising: field magnet through holes that are arranged annularly in a circumferential direction around a predetermined direction along an axis of rotation, said field magnet through holes being adjacent each other in said circumferential direction and forming a pair, each of said field magnet through holes having a pair of ends in said circumferential direction; and a connecting portion provided between said field magnet through holes forming a same said pair, said connecting portion having, as sides, said ends that belong to different said field magnet through holes and that are adjacent each other in said circumferential direction, one of said sides having at least one curved portion along a circle around a position being on the side opposite to said connecting portion with respect to said one of said sides, a radius of said circle satisfying a ratio of not less than 1.0 nor more than 1.5 with respect to a length of said at least one curved portion in a direction perpendicular to a first extension direction in which one of said field magnet through holes extends from said correcting portion, and a tangent to said at least one curved portion seen from said predetermined direction along an axis of rotation being along a second extension direction of extension of said connecting portion only at one predetermined position between both ends of said at least one curved portion.