The compact motor is capable of improving characteristics of torque. In the motor, a stator core includes a main core and a sub-core. The main core is constituted by piling a plurality of first core plates, which respectively have first extended pole sections of the same number. The sub-core is provided on the base plate side of the main core and is constituted by at least one second score plate, which has second extended pole sections whose number is less than that of the first extended pole se...

In a permanent magnet-embedded, concentrated winding motor, plurality of stator teeth are divided into, for example, three groups that include a plurality of adjacent stator teeth having coils wound around and that are provided with voltage in phase that are set as one group. Coils are wound in opposite directions around adjacent stator teeth in the same group, while the relation between the angle h of a slot opening between adjacent stator teeth of the same group and the angle H of a slot openi...

A motor of this invention is provided with a sleeve-type bearing impregnated with oil for supporting a rotor assembly including a shaft and a rotor member. A lower face of the rotor is provided with at least two peripheral wall portions, an inner peripheral wall portion and an outer peripheral wall portion, which surround the shaft with a gap therebetween in a radial direction. The peripheral wall portions are accommodated in an annular recessed portion so as to surround an open space over a sle...

A motor includes a first stator yoke which is excitable by energization into a first coil, a second stator yoke which is excitable by energization into a second coil, and a rotor which can be driven for rotation under the control of energization into the first coil and the second coil, wherein the first stator yoke and the second stator yoke are disposed in the rotational axial direction of the rotor, while the rotor is provided with a rotational output portion which can take out the rotational ...

A motor incorporates a rotor 21 incorporating a cylindrical magnet 24 which has segments magnetized at predetermined pitches in a circumferential direction thereof; and a stator 25 for imparting a rotating magnetic field to the magnet 24 so as to rotate the rotor 21. Each of the magnetized segments is magnetized such that the inner portion and the outer portion are magnetized to different polarities and the magnetized segments disposed at adjacent pitches are magnetized to opposite polarities. T...

A rotor magnet includes a first polarized layer alternately polarized into different poles while being circumferentially divided into n parts, and a second polarized layer alternately polarized into different poles. An advance phase angle as .theta.1 with respect to the first polarized layer is set and the magnet is circumferentially divided into n parts. First and second coils are disposed in an axial direction of the rotor magnet. A first outer magnetic pole and a first inner magnetic pole, wh...

A motor comprises a housing, a cylindrical stationary shaft placed upright on the housing, and a rotational shaft rotatably and coaxially supported by the stationary shaft. The rotational shaft has a cylindrical hollow portion coaxially formed therewith, open at one end of the rotational shaft, and into which the stationary shaft is inserted. The motor further comprises a first dynamic pressure type bearing formed on the outer peripheral surface of the stationary shaft for generating a dynamic p...

In a motor in which the currents to the exciting coils are controlled by the signals from the Hall elements (H1, H2) which detect the pole positions of a permanent magnet (Mg), the Hall elements are positioned at an electrical angle of 45.degree. with respect to the exciting coils (22, L1, L2, L3, L4), and the output signals of said Hall elements are converted into pulses for conducting digital control of the currents to the exciting coils.

A motor has an armature disposed on one of a rotor and a stator and a permanent magnet disposed on the other of the rotor and the stator. The permanent magnet has skewed magnetic poles being magnetized so that a boundary between each pair of skewed magnetic poles is generally S-shaped and opposed areas of pole surfaces of the permanent magnet and the armature gradually increase when the pole surface of the permanent magnet enters a magnetic field region of the pole surface of the armature or gra...

FET power transistors of a power supplying part execute high-frequency switching operation and form current paths to three-phase windings. A voltage detecting part compares terminal voltages of the three-phase windings and produces a detected pulse signal in response to a comparison result. A state shifting part and an activation control part control active periods of the FET power transistors in response to the detected pulse signal. A commanding part produces a command signal in response to an...