Dc motor with rotor slots closely spaced

In a direct current motor including:

• a substantially cylindrical rotor core having a peripheral face and front and rear end faces;
• and a lead wire wound around the rotor core to form a rotor coil, the improvement wherein the rotor core having a plurality of shallower slots and a plurality of deeper slots, the shallower and deeper slots being circumferentially and alternately disposed in the peripheral face of the rotor core at angular intervals about the center axis of the rotor core so that each of the shallower and deeper slots extends axially from the front face to the rear face of the rotor core, whereby axially extending teeth are formed among the shallower and deeper slots, each of the shallower slots including first outer and inner radially aligned sections, each receiving a portion of the lead wire, each of the deeper slots including:
• second outer and inner radially spaced sections, each receiving a portion of the lead wire, the second outer section being arranged at such a position that the distance between the second outer section and the center axis of the rotor core is substantially equal to the distance between the center axis of the rotor core and the first outer section of each of the shallower slots, the second inner section being arranged at such a position that the distance between the second outer and inner sections is larger than the distance between the first outer and inner sections of each of the shallower slots;
• and a neck section interposed between the second outer and inner sections, the neck section having a width substantially smaller than widths of the second outer and inner sections.