Rotating electric machine

A rotating electric machine comprising:

• a rotor having a cylindrical boss with a rotation axis;
• a plurality of ribs extending radially outward from the cylindrical boss;
• a cylindrical yoke connecting outer radial ends of the plurality of ribs;
• a plurality of soft magnetic material poles extending radially outward from the cylindrical yoke;
• a plurality of magnetic poles extending radially outward from the cylindrical yoke at positions between the plurality of the soft magnetic material poles, and each magnetic pole having a magnet hole;
• a plurality of permanent magnets positioned within the cylindrical yoke, the plurality of permanent magnets having a thickness direction aligned with a radial direction of the cylindrical yoke, and each permanent magnet positioned within each magnet hole;
• a back yoke having a cylindrical shape connecting a plurality of teeth that are positioned along an inner periphery of the back yoke and extend radially inward toward the rotor from the inner periphery of the back yoke;
• and
• a winding disposed in a slot that is defined as a space between each of the plurality of teeth, wherein
• each magnetic pole has (i) a magnetism transfer part positioned outside of the magnet hole such that the magnetism transfer part extends radially outward with respect to the rotation axis and relative to the magnet hole, and (ii) a connecting part connecting circumferential ends of the magnetism transfer part,
• a width of the cylindrical yoke in the radial direction is defined as ‘a’,
• a width of the magnetism transfer part of the magnetic pole in the radial direction is defined as ‘b’,
• 2.0≦(a/b)≦2.7,
• a shortest distance of a gap between the rotor and the plurality of teeth is defined as δ, and
• 2δ≦b≦4δ.