Patent ID: 7737600

Claim:
A motor generator comprising: a stator, formed in a hollow cylindrical shape, and a rotor rotatably mounted with respect to the stator, the stator comprising, a stator core including a yoke part which is annularly extended and a teeth part which has a plurality of teeth annularly disposed on an inner circumference side of the yoke part so as to point inward along a radial direction, and a coil wound around each of the plurality of teeth; the yoke part comprising, a protrusion that protrudes from each axial end face of the plurality of teeth towards an outside along an axial direction, wherein each of the plurality of teeth has an axial length which gradually decreases towards yoke part side being an outside along the radial direction, and a circumferential length which gradually increases towards yoke part side being an outside along the radial direction, each of the plurality of teeth has cross sections perpendicular to the radial direction which are substantially equal in areas along the radial direction and the area of a cross section of the yoke part perpendicular to the circumferential direction is one-half the area of the cross section of the tooth perpendicular to the radial direction, or greater.