An electric motor includes a yoke having a cylindrical section, two pairs of permanent magnets disposed at an inner circumferential surface of the cylindrical section to oppose each other, and an armature rotatably supported further inside in a radial direction than the permanent magnets, wherein at least a pair of first flat sections opposing each other in the radial direction are formed at the cylindrical section, and the permanent magnets are disposed at positions distant from the first flat sections.

An electric motor includes a yoke having a cylindrical section, two pairs of permanent magnets disposed at an inner circumferential surface of the cylindrical section to oppose each other, and an armature rotatably supported further inside in a radial direction than the permanent magnets, wherein at least a pair of first flat sections opposing each other in the radial direction are formed at the cylindrical section, and the permanent magnets are disposed at positions distant from the first flat sections.

A wave winding for a stator of an electric machine is configured to be placed in a series of stator grooves located along a periphery of the machine to increase power and efficiency of the machine by avoiding losses, particularly during upper rotational speed range operation. The wave winding has at least two conductors for one respective phase of the machine. The conductors are interconnected in parallel and/or series and can be disposed at a given winding pitch in a number of at least two successive stator grooves of each magnetic pole and each phase of the machine in a sequence predefined for each phase and for one respective magnetic pole along the periphery of the machine. The predefined sequence at least of the conductors interconnected in parallel is transposed by at least one groove skip in at least one position along the periphery of the machine.

An electric motor includes a yoke having a cylindrical section, two pairs of permanent magnets disposed at an inner circumferential surface of the cylindrical section to oppose each other, and an armature rotatably supported further inside in a radial direction than the permanent magnets, wherein at least a pair of first flat sections opposing each other in the radial direction are formed at the cylindrical section, and the permanent magnets are disposed at positions distant from the first flat sections.

An electric motor includes a yoke having a cylindrical section, two pairs of permanent magnets disposed at an inner circumferential surface of the cylindrical section to oppose each other, and an armature rotatably supported further inside in a radial direction than the permanent magnets, wherein at least a pair of first flat sections opposing each other in the radial direction are formed at the cylindrical section, and the permanent magnets are disposed at positions distant from the first flat sections.

An electric motor includes a yoke having six magnetic poles; a rotary shaft which is provided inside the yoke in a freely rotatable manner; an armature core (6) which has teeth (36) attached to the rotary shaft, radially extending in a radial direction and set in an arrangement of an even number, and an even number of slots (37) formed between the teeth; an armature coil (7) which is wound around the teeth in a single wave winding; and a commutator (13) which is provided in the rotary shaft to be adjacent to the armature core (6) and has a plurality of circumferentially disposed segments (41) to which the armature coil (7) is connected.

An electric motor includes a yoke having six magnetic poles; a rotary shaft which is provided inside the yoke in a freely rotatable manner; an armature core (6) which has teeth (36) attached to the rotary shaft, radially extending in a radial direction and set in an arrangement of an even number, and an even number of slots (37) formed between the teeth; an armature coil (7) which is wound around the teeth in a single wave winding; and a commutator (13) which is provided in the rotary shaft to be adjacent to the armature core (6) and has a plurality of circumferentially disposed segments (41) to which the armature coil (7) is connected.

A wave winding for a stator of an electric machine is configured to be placed in a series of stator grooves located along a periphery of the machine to increase power and efficiency of the machine by avoiding losses, particularly during upper rotational speed range operation. The wave winding has at least two conductors for one respective phase of the machine. The conductors are interconnected in parallel and/or series and can be disposed at a given winding pitch in a number of at least two successive stator grooves of each magnetic pole and each phase of the machine in a sequence predefined for each phase and for one respective magnetic pole along the periphery of the machine. The predefined sequence at least of the conductors interconnected in parallel is transposed by at least one groove skip in at least one position along the periphery of the machine.

The purpose of the present invention is to provide a direct current motor wherein the number of coil-connecting wires that cross the outer surface of a coil end part is reduced. In a direct current motor that is provided with an armature that has a plurality of armature slots and has an armature coil that is wound so as to span two armature slots that are separated by a fixed number of armature slots, a lowermost layer of a coil end part is provided with at least four armature coils that are wound through other armature slots so as not to coincide with the wound armature coil, and a layer above the four armature coils that are wound on the bottommost layer is provided with at least four armature coils that are wound in the same manner as the four armature coils.

The purpose of the present invention is to provide a direct current motor wherein the number of coil-connecting wires that cross the outer surface of a coil end part is reduced. In a direct current motor that is provided with an armature that has a plurality of armature slots and has an armature coil that is wound so as to span two armature slots that are separated by a fixed number of armature slots, a lowermost layer of a coil end part is provided with at least four armature coils that are wound through other armature slots so as not to coincide with the wound armature coil, and a layer above the four armature coils that are wound on the bottommost layer is provided with at least four armature coils that are wound in the same manner as the four armature coils.