Magnetic core

A core in which a plurality of core pieces have their ends connected to each other to form the shape of a ring,

• the core pieces have magnetic pole teeth projecting nearly perpendicular to the direction of connecting, a connecting portion is formed on one of the ends, a first end surface of the one of the ends is formed in the shape of a circular arc centered on the connecting portion, and the other end is formed with a second end surface which can mate with the first end surface of an adjoining core piece, and
• a first core member having the cores arranged in the shape of a strip through the end surfaces and a second core member having the cores arranged in the shape of a strip in the opposite direction from the direction of connection of the first core member are stacked such that the ends of adjoining core pieces in the stacking direction overlap each other and the connecting portions are connected so as to be able to freely pivot such that it can be formed into the ring shape with the magnetic pole teeth on the interior,
• characterized in that a cutout is formed in the corner on the outer side of the core in the second end surface of each core piece.