Hybrid magnet type DC motor

A hybrid magnet type DC motor comprising:

• a commutation device;
• an armature having a rotation core and a plurality of rotation coils that are wound around the rotation core, wherein direct current is supplied to the rotation coils through the commutation device;
• a cylindrical stator that is constituted as a hybrid magnet, said cylindrical stator having a circumferential direction, a radial direction, and an axial direction, wherein the stator surrounds the armature, wherein the stator has a plurality of electromagnets and permanent magnets that are alternately arranged in the circumferential direction of the stator, wherein each electromagnet has a fixed core and a fixed coil that is wound around the fixed core, wherein each fixed core has a pole core that faces to the rotation core and has an approximately arched cross-sectional shape and a projection that extends outward in the radial direction of the stator from a middle portion of the pole core in the circumferential direction, wherein the fixed coil is wound around the projection, wherein, when direct current is supplied to the fixed coils, the pole cores are alternately magnetized to be N- and S-poles in the circumferential direction of the stator;
• and
• a cylindrical fixed yoke through which magnetism permeates, wherein the fixed yoke accommodates the armature and the stator, wherein an inner surface of the fixed yoke is magnetically separated from the permanent magnets and contacts the projections,
• wherein the permanent magnets are anisotropic magnets, wherein each permanent magnet includes a inner curved surface and a outer curved surface opposite to the inner curved surface in the radial direction of the stator, the inner curved surface being magnetized and the outer curved surface being non-magnetized, wherein the inner curved surface of each permanent magnet contacts two pole cores that are arranged in both sides of each permanent magnet in the circumferential direction of the stator and have different polarities from each other, wherein the inner curved surface has an S-pole portion and an N-pole portion, the S-pole portion being provided in one side of the inner curved surface in the circumferential direction and the N-pole portion being provided in the other side of the inner curved surface in the circumferential direction, and wherein the S-pole portion contacts the pole core that is magnetized to be an S-pole and the N-pole portion contacts the pole core that is magnetized to be an N-pole.