Abstract: The disclosure describes a DC motor including a rotor unit arranged within the motor body and has a cylindrical field magnet fixed to an outer surface of a holder. The holder has a rotating shaft press-fitted through the center, and the cylindrical field magnet has the S and the N poles alternately around a circumference. There is a stator unit which is circumferentially arranged around the rotor unit, that is made of a plurality of stator yokes that are arranged so that they oppose the field magnet through a small gap. Each of the stator yokes is formed by circumferentially stacking a large number of thin plates, each consisting of a salient pole, and a number of coil units, each formed by winding a magnet wire on a bobbin, and mounting the bobbins on the stator yokes. In the described arrangement, each of the S and N poles has a plurality of stages formed in an axial direction and shifted from each other in the circumferential direction by a predetermined shift amount with respect to the field magnet.

Abstract: An electric rotary machine includes a stator comprising: a stator ring; a plurality of discrete salient poles each comprising a bobbin with guide grooves and a pole tooth with a groove, disposed inside the stator ring, and fixed by a molding resin injected inside the stator ring; and a positioning ring having protrusions at its outer circumference and engaging with the discrete salient poles such that the protrusions are each fitted into the groove of the pole tooth.

Abstract: An electric rotary machine is provided, in which a stator armature includes a stator ring that encloses a plurality of salient poles each with a pole tooth thereby forming a magnetic circuit, and in which the inner surface of the stator ring is made flat at portions to be in contact with the outer end faces of the pole teeth so that the stator ring can make surface-to-surface contact with the pole teeth without any air gap therebetween so as to secure a well-balanced magnetic circuit.

Abstract: An electric rotary machine includes a stator armature which comprises: a stator ring; a plurality of discrete salient poles each including a pole tooth and a coil, disposed inside the stator ring thereby forming a magnetic circuit, and fixed by a molding resin injected inside the stator ring from an injection port of a molding die; and a plurality of barrier walls. Each of the barrier walls is disposed between the injection port of the molding die and two coil terminal pins to which the coil has its both wire terminations connected respectively.

Abstract: An electric rotary machine comprises: a cylindrical pole tooth ring provided with a plurality of slits; and a plurality of salient poles each including a pole tooth. The salient poles are each positioned and fixed such that the pole tooth is fitted into the slit, which, by means of openings formed on the pole tooth ring along and close to the side wall of the slit, is adapted to be elastically deformed when receiving the pole tooth fitted thereinto.

Abstract: An electric rotary machine includes a stator comprising: a stator ring; a plurality of discrete salient poles each comprising a pole tooth, disposed inside the stator ring thereby forming a magnetic circuit, and fixed by a molding resin injected inside the stator ring; and a plurality of bobbins each constituting the salient pole, adapted to lodge the pole tooth fitted thereinto and to have a magnet wire wound thereon, and each including its outward-positioned flange having at its respective both ends two flexible thin-walled extensions which are adapted to securely hold the wound magnet wire in place, stay unbent during winding operation, and which are bent when the salient poles are put inside the stator ring.

Abstract: An electric rotary machine comprises a cylindrical pole tooth ring and a plurality of salient poles each including a pole tooth. The salient poles are each positioned and fixed such the pole tooth makes firm contact with the pole tooth ring by means of each of a plurality of mechanisms, which are arrayed circumferentially on the pole tooth ring, and which each comprise bend-ups adapted to be elastically deformed when the pole tooth is fitted into the mechanism.

Abstract: An electric rotary machine is provided, in which a stator armature includes a stator ring that encloses a plurality of salient poles each with a pole tooth thereby forming a magnetic circuit, and in which the inner surface of the stator ring is made flat at portions to be in contact with the outer end faces of the pole teeth so that the stator ring can make surface-to-surface contact with the pole teeth without any air gap therebetween so as to secure a well-balanced magnetic circuit.

Abstract: An electric rotary machine includes a stator comprising: a stator ring; a plurality of discrete salient poles each comprising a bobbin with guide grooves and a pole tooth with a groove, disposed inside the stator ring, and fixed by a molding resin injected inside the stator ring; and a positioning ring having protrusions at its outer circumference and engaging with the discrete salient poles such that the protrusions are each fitted into the groove of the pole tooth.

Abstract: An electric rotary machine includes a stator armature which comprises: a stator ring; a plurality of discrete salient poles each including a pole tooth and a coil, disposed inside the stator ring thereby forming a magnetic circuit, and fixed by a molding resin injected inside the stator ring from an injection port of a molding die; and a plurality of barrier walls. Each of the barrier walls is disposed between the injection port of the molding die and two coil terminal pins to which the coil has its both wire terminations connected respectively.

Abstract: An electric rotary machine includes a stator comprising: a stator ring; a plurality of discrete salient poles each comprising a pole tooth, disposed inside the stator ring thereby forming a magnetic circuit, and fixed by a molding resin injected inside the stator ring; and a plurality of bobbins each constituting the salient pole, adapted to lodge the pole tooth fitted tehreinto and to have a magnet wire wound thereon, and each including its outward-positioned flange having at its respective both ends two flexible thin-walled extensions which are adapted to securely hold the wound magnet wire in place, stay unbent during winding operation, and which are bent when the salient poles are put inside the stator ring.

Abstract: An electric rotary machine comprises a cylindrical pole tooth ring and a plurality of salient poles each including a pole tooth. The salient poles are each positioned and fixed such the pole tooth makes firm contact with the pole tooth ring by means of each of a plurality of mechanisms, which are arrayed circumferentially on the pole tooth ring, and which each comprise bend-ups adapted to be elastically deformed when the pole tooth is fitted into the mechanism.

Abstract: An electric rotary machine comprises: a cylindrical pole tooth ring provided with a plurality of slits; and a plurality of salient poles each including a pole tooth. The salient poles are each positioned and fixed such that the pole tooth is fitted into the slit, which, by means of openings formed on the pole tooth ring along and close to the side wall of the slit, is adapted to be elastically deformed when receiving the pole tooth fitted thereinto.

Abstract: A DC motor of the present invention includes a rotor unit which is rotatably arranged within the motor and has a cylindrical field magnet fixed to an outer surface of a holder into which a rotating shaft is press-fitted at a center thereof, said cylindrical field magnet being magnetized such that S and N poles alternate with each other in a circuferential direction thereof, and a stator unit which is circumferentially arranged around the rotor unit and is comprised of a plurality of stator yokes so arranged as to oppose the field magnet with a small gap, each of the stator yokes being formed by circumferentially stacking a large number of thin plates, each consisting a salient pole, and a plurality of coil units, each being formed by winding a magnet wire on a bobbin and mounted on each of the stator yokes. Thus, each of the S and N poles has a plurality of stages formed in an axial direction and shifted from each other in the circumferential direction of said field magnet with a predetermined shift amount.

Abstract: Between rotation shaft 1a and the frame 4, two bearings 5 having inner races 5b narrower in width compared with outer races 5a are disposed and each of end faces of outer races 5a is made to abut each other. Since in general, the outer race and the inner race are secured in the size precision, by making each end faces of the outer race to abut each other, an assembling precision between two bearings 5 is secured. Further, spacing secured between inner races 5b enables to displace the inner ring 5b minutely due to the preload to be given to the end face of the inner races 5b at the time of assembling of the spindle motor, which is expected to absorb a minute play inevitable to the bearings, as a result to increase the rotation precision after completion of the spindle motor.