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 rotor having an index signal generating portion on a rotor magnet and a magnetic resistance sensor having a magneto-sensitive surface. The sensor is positioned on a stator of the motor facing the index signal generating portion of the rotor with a predetermined gap. The sensor functions to sense an index signal in the magnetic field generated by the index signal generating portion during the rotation of the rotor. A speed detection circuit is included for detecting the speed ...

A motor provided with a rotor magnet circumferentially divided into n section which are alternately magnetized to different poles, a coil disposed axially of the rotor magnet, outer magnetic poles and inner magnetic poles excited by the coil being opposed to the outer peripheral surface and inner peripheral surface, respectively, of the rotor, and a holder for holding the rotor magnet at a position at which the centers of the poles of the magnet deviate from a line linking the centers of the out...

An electromagnetic drive apparatus comprises a stator yoke excited with supply of power to a coil, a rotor arranged as capable of being driven by excitation of the stator yoke so as to move a driven member, and a fixed member for positioning and supporting the rotor and the stator yoke. The stator yoke has a projecting portion or a recessed portion and the stator yoke is positioned and supported relative to the fixed member by the projecting portion or the recessed portion to provide a compact m...

A motor has a stator and a rotor that is formed of two rotor parts fitted on a rotor shaft in a fashion preventing the rotor from rotating relative to the rotor shaft. The rotor parts carry permanent magnets arranged with a fixed pitch angle over their outer peripheral faces. The rotor shaft has a single key for engaging with both an engagement groove of the first rotor and an engagement groove of the second rotor. The engagement groove of each steel plate forming the rotor parts is formed in a ...

A motor comprises a rotary shaft, an oil impregnated sintered bearing rotatably supporting the rotary shaft, a bearing holder supporting the oil impregnated sintered bearing and a motor case. A lateral pressure device is provided to the rotary shaft which abrasively contacts the rotary shaft from a radial direction and provides a lateral pressure so that the rotary shaft is displaced in the radial direction. The lateral pressure device further comprises an inner ring made of an oil impregnated s...

A motor comprises a motor rotation shaft, a first thrust bearing which supports one end of the motor rotation shaft and a second thrust bearing which supports the other end of the motor rotation shaft to control positioning in a thrust direction of the motor rotation shaft. The first thrust bearing further comprises a bearing for supporting one end of the motor rotation shaft and is movable in a shaft direction of the motor rotation shaft, a guide member for guiding the movement of the bearing i...

A motor includes a rotor, a stator having a core, end brackets, and plural binders. The stator core has plural layers and a plurality of axially extending dovetail grooves in its cylindrical outer surface and arranged at predetermined spacing around its circumference. The brackets are each a bottomed cylinder with a bearing bottom portion supporting the rotor shaft. Plural projections are formed at the axially inner end of each of the brackets and project axially inward into the dovetail grooves...

The motor has a motor housing. The motor housing supports therein rotatably an armature having a rotating shaft and a commutator. Brushes are brought into friction contact with the commutator. The brushes have brush holders for holding them respectively. The brush holders are attached to a base plate having a first side and a second side. A plurality of electric parts are mounted on the base plate. These electric parts are allocated to the first side and the second side of the base plate.

A motor has a stator assembly, a rotor assembly having a rotary shaft, a bearing unit that rotatably supports the rotary shaft with respect to the stator assembly, and a case body that generally houses the stator assembly and the rotor assembly. The case body includes a bottom surface section, a recessed concave section that is located radially inside the bottom surface section and concaves inwardly in an axial direction at an area opposing an excitation coil of the stator assembly, and a bearin...