Abstract: A motor device suppressed in tilt of the rotor shaft and improved in resistance to rotational vibration without enlarging the thickness direction. A stator plate 1 supports a radial bearing 3 and thrust bearing 5 through an auxiliary support plate 15. The auxiliary support plate 15 has a bent flange 15a at its outer circumference, has the radial bearing 3 fastened to the region inside the flange 15a, and has the thrust bearing 5 placed on the inside region so as to surround the same. The auxiliary support plate 15 is made to fit in the stator plate 1, while the flange 15a is supported on the top surface of the stator plate 1. The rotor plate 9 has a rotor shaft 11 and drive magnet 13. The rotor shaft 11 is axially supported by the radial bearing 3 and abuts against the thrust bearing 5.

Abstract: In a bearing arrangement including a thrust bearing and a radial bearing, the thrust bearing includes a first thrust plate which is fixedly secured to a stator plate, and the radial bearing is integrally attached to the first thrust plate of the thrust bearing. Because the radial bearing is directly attached to the first thrust plate of the thrust bearing, the perpendicularity of the radial bearing with respect to the thrust support surface can be easily ensured. Also, the first thrust plate normally consists of a highly rigid member, and this also contributes in the favorable perpendicularity of the radial bearing with respect to the thrust support surface. This bearing arrangement is useful in a spindle motor for turning a floppy disk in a floppy disk drive.

Abstract: A motor includes an armature and a field magnet which surrounds the armature. The armature includes a plurality of teeth being arranged at equal pitch, and the field magnet includes a plurality of magnetic poles being arranged at equal pitch. When the number of the magnetic poles of the field magnets is "2P" and the number of phases of divided armature windings is "Q", the number T of the teeth is determined in accordance with an equation T=(P.+-.N) Q (O<N<N<P-2P/Q). In addition, "phase" and "winding direction" of the divided armature windings to be wound on the respective teeth are determined through comparison of an actual angle in electrical degrees of respective one of teeth and an ideal angle in electrical degrees corresponding thereto.

Abstract: A frequency generator comprises a cylindrical rotor to which an annular multipolar magnet is fixed on the inner wall thereof. The multipolar magnet includes a plurality of magnetizable sectors arranged in a circumferential direction thereof, and adjacent magnetizable sectors are magnetized alternately in reverse polarity. Within the rotor, two disk-shaped magnetic plates are supported fixedly with a predetermined space axially. On the peripheries of respective magnetic plates, a plurality of salient poles are formed with a predetermined pitch in a circumferential direction thereof. The salient poles of each magnetic plate respectively constitute a salient-pole line. Between the two salient-pole lines, a generating coil is wound in a circumferential direction thereof. To each first and second salient poles to be paired, the magnetizable sectors of different polarity of the multipolar magnet are faced in divergence relatively in the circumferential direction.

Abstract: A brushless motor (10) comprises a stator yoke plate (16) made of a magnetic material, to which both main surfaces the first and the second flexible printed circuit boards (20) (22) formed integrally including a connecting part (24) are stuck respectively. On the first flexible printed circuit board (20), a plurality of driving coils (30) are arranged annularly and a conductor pattern for a speed detecting coil is formed inside the driving coils (30). On the integrated stator yoke plate (16) and the first and second flexible printed circuit boards (20) (22), a penetrated hole (18) for passing through a rotor shaft (54) is formed generally in the center. A tongue (36) is formed generally in protrusion inwardly from the periphery defining the penetrated hole (18) on which a connecting conductor pattern connected to the speed detecting coil is formed.