A brushless DC motor wherein a rotor has a motor shaft, a rotor yoke mounted on the motor shaft, and a ring-shaped magnet magnetized so as to have a plurality of magnet poles in the circumferential direction thereof, and held by the rotor yoke. A stator has first and second stator yokes each having main magnetic poles extending in the radial direction from the center thereof, magnetic pole pieces extending in the vertical direction from tip ends of the main magnetic poles along an inner peripheral surface of the ring-shaped magnet, a center yoke surrounding the motor shaft for connecting magnetically said first and second stator yokes, a winding assembly having an annular winding, and a printed wiring board, on which the annular winding, a electromagnetic conversion element and a driving circuit are mounted.

A motor has a rotatably supported rotor shaft and a rotator that rotates together with the rotor shaft. The rotator includes a shaft insertion section that has an internal peripheral surface and a specified length in an axial direction in which the rotor shaft is inserted. The internal peripheral surface has a first internal peripheral surface of a small diameter and a second internal peripheral surface having a diameter slightly greater than that of the first internal peripheral surface. The first internal peripheral surface engages the rotor shaft under a pressure, and the second internal peripheral surface is slightly spaced a distance from the rotor shaft, such that a gap is created between the second internal peripheral surface and the rotor shaft. The rotor shaft is pressure-inserted in the first internal peripheral surface to be affixed to the rotator, and an adhesive is filled in the gap between the second internal peripheral surface and the rotor shaft to affix the second internal surface to the rotator.

A claw pole dynamo includes an annular member having a magnet extending in a circumferential direction thereof for rotation around an axis; a first stator yoke having a first annular portion and a plurality of first pole shoes extending in a direction of the axis and in close proximity to the magnet, wherein the first annular portion defines a plurality of first discontinuities (such as slots) in a circumferential direction thereof for suppressing eddy currents in the first annular portion; a second stator yoke having a second annular portion and a plurality of second pole shoes extending in the direction of the axis and in close proximity to the magnet, wherein the plurality of first pole shoes are interleaved with the plurality of second pole shoes in the circumferential directions of the first and second annular portions; a core yoke for magnetically coupling the first stator yoke and the second stator yoke and for transmitting a magnetic flux in the direction of the axis; and a coil disposed around the core yoke. The plurality of discontinuities suppress the eddy currents in the first stator yoke. If desired, the second stator yoke could have a similar plurality of discontinuities in the second annular portion thereof to suppress eddy currents in the second annular portion. A first separation member with a plurality of discontinuities may be disposed between the first stator yoke and the core yoke to further suppress eddy currents, and the core yoke may include a plurality of sections disposed at different positions in a circumferential direction of the core yoke to further reduce eddy currents.

A motor includes a rotor equipped with a magnet magnetized in multiple poles, a stator yoke having claw poles with plural pole teeth disposed opposing to one another and arranged in a cylindrical shape extending in an axial direction and around an outer periphery of the rotor in a circumferential direction, a bobbin formed from a coil wound around the stator yoke, and a cylindrical motor case that houses the rotor, the stator yoke and the bobbin. The cylindrical motor case is formed from conductive material and uses as at least a part of the yoke. The motor case defines generally parallel planes tangential to an outer periphery of the coil, and has side wall sections extending in close proximity to the parallel planes and defining plane opening sections, and a part of an outer peripheral surface of the coil of the bobbin protrudes from the opening sections.

A linear motor includes tubular outer yoke (4), tubular inner yoke (3) disposed in outer yoke (4), coil (2) provided to inner yoke (3), permanent magnet (5a, 5b) vibrating following a magnetic flux produced by coil (2), and vibrator (6) made of magnetic material and supporting permanent magnets (5a, 5b). Magnetic loop produced by outer yoke (4) and inner yoke (3) travels through vibrator (6) free from interference by vibrator (6) because vibrator (6) is made of magnetic material. As a result, the linear motor vibrates efficiently.