Abstract: A motor includes a rotor including a shaft arranged along a central axis extending in one direction; and a stator arranged radially outside of the rotor. The stator includes a stator core including an annular core back portion arranged to surround the rotor, and a plurality of tooth portions arranged to extend radially inward from the core back portion; and coils each of which is wound around a separate one of the tooth portions. The tooth portions are arranged side by side along a circumferential direction. An inner edge of the core back portion is in the shape of a polygon when viewed along an axial direction. The inner edge includes rounded corners each of which is arranged between portions of the inner edge to which circumferentially adjacent ones of the tooth portions are joined. When D1 denotes an inside diameter of the stator core, D2 denotes a minimum outside diameter of the stator core, and N denotes the number of tooth portions, the ratio of D1 to D2 is greater than 0.

Abstract: An inner-rotor-type motor includes four outer surface portions flush or substantially flush with the motor outer surface of the core-back portion provided in the frame portion of each of the two insulating members of the insulator to secure electrical insulation between the stator core and the coil. The outer surface portions of the frame portion of each of the insulating members are inserted between the leg portions of four corners of each of the cover members attached to the axial opposite sides of the stator core. In this state, the cover members are attached to the stator core. The inner-rotor-type motor makes it possible to easily and cost-effectively manufacture a cover member without impairing the dust-proofness of the interior of the motor and greatly improves ease of assembly.

Abstract: An inner-rotor-type motor, includes four outer surface portions flush or substantially flush with the motor outer surface of the core-back portion provided in the frame portion of each of the two insulating members of the insulator to secure electrical insulation between the stator core and the coil. The outer surface portions of the frame portion of each of the insulating members are inserted between the leg portions of four corners of each of the cover members attached to the axial opposite sides of the stator core. In this state, the cover members are attached to the stator core. The inner-rotor-type motor makes it possible to easily and cost-effectively manufacture a cover member without impairing the dust-proofness of the interior of the motor and greatly improves ease of assembly.

Abstract: A hybrid rotary electrical machine that obtains a deviation angle of about one half of a pole teeth pitch between magnetic teeth of two rotor magnetic pole members gripping a permanent magnet of a rotor including rotor magnetic pole members that include the magnetic teeth at an equal pitch T on a surface thereof. The rotor magnetic pole members include cutout portions on the inner circumferential surface or the outer circumferential surface of the rotor magnetic pole members in a specified positional relationship with respect to the magnetic teeth. The cutout portions of one of the rotor magnetic pole members are axially aligned with the cutout portions of the other rotor magnetic pole member turned upside down so the magnetic teeth of one of the rotor magnetic pole members have a phase difference of about T/2 with respect to the magnetic teeth of the other rotor magnetic pole member.

Abstract: In an industrial robot having a plurality of arms, each arm is coupled with other elements such as a mounting base, another arm, a robotic hand, and revolved by a motion of a revolving joint. A motor for moving the revolving joint, an encoder for sensing a rotation angle of a drive shaft of the motor, and a control circuit for controlling the driving of the motor are provided on the same arm. A signal cable for transmitting a sensing signal of the encoder to the control circuit is terminated at the control circuit on the same arm. There is no need to align the signal cable from the encoder to a main control circuit provided in the mounting base.

Abstract: A stator of the stepping motor of the invention includes an annular shaped yoke portion, a stator iron-core having twelve stator main poles each having a plurality of small teeth on the tip end thereof and stator coils wound in the stator iron-core as three-phase winding. The stator rotatably supports a hybrid type rotor having a cylindrical permanent magnet that is sandwiched between a pair of rotors each having pole teeth around the circumferential surface to be opposite to the small teeth. Second, third, fourth and fifth harmonic components are removed by composing cogging torque of the respective phases by means of the three-phase twelve-pole construction. Any one harmonic component of the cogging torque among the second to fifth harmonic components is independently erased by making a difference between the small teeth pitch and the rotor teeth pitch, thereby the selected harmonic component is doubly erased.

Abstract: Disclosed is an inner rotor or outer rotor hybrid stepping motor of 6-phase/6 m-pole type or 10-phase/10 m-pole type. The motor includes a stator that has 6 m or 10 m pieces of magnetic poles and a rotor that is rotatably supported by the stator. Excitation windings are wound around the stator magnetic poles. The stator magnetic pole is divided into two halves in the axial direction, one half has pole teeth being line-symmetric and the other half has pole teeth being asymmetric and deviated from the symmetric pole teeth by ¼ pitch. The positions of the symmetric half and the asymmetric half are inverted between the adjacent magnetic poles. The rotor has a first and second rotor units each of which includes a permanent magnet and first and second rotor magnetic poles around which pole teeth are formed with deviation of ½ pitch.

Abstract: A permanent magnet motor having a stator and a permanent magnet rotor facing the stator with a gap therebetween, the stator having a plurality of stator magnetic poles extending radially toward a peripheral surface of the rotor, s number of small stator teeth formed on a tip end of each of the magnetic poles, and exciting windings of m phases wound around the stator magnetic poles. The rotor having a cylindrical permanent magnet having pieces of N pole and pieces of S pole arranged alternately in a peripheral direction thereof at equal pitches, wherein a pitch of the small stator teeth is 1±1/(2ms) times larger than a pitch of the rotor magnetic pole pairs. The width of the small stator tooth is 37˜47% of the magnetic pole pitch. A depth of the groove formed between the adjacent small stator teeth is more than 15 times larger than the length of the air gap between the stator and the rotor.

Abstract: In an industrial robot having a plurality of arms, each arm is coupled with other elements such as a mounting base, another arm, a robotic hand, and revolved by a motion of the revolute joint. A motor for moving the revolute joint, an encoder for sensing a rotation angle of a drive shaft of the motor, and a control circuit for controlling the driving of the motor are provided on the same arm. A signal cable for transmitting a sensing signal of the encoder to the control circuit is terminated at the control circuit on the same arm. There is no need to align the signal cable from the encoder to a main control circuit provide in the mounting base.

Abstract: A permanent magnet motor having a stator and a permanent magnet rotor facing the stator with a gap therebetween, the stator having a plurality of stator magnetic poles extending radially toward a peripheral surface of the rotor, s number of small stator teeth formed on a tip end of each of the magnetic poles, and exciting windings of m phases wound around the stator magnetic poles. The rotor having a cylindrical permanent magnet having pieces of N pole and pieces of S pole arranged alternately in a peripheral direction thereof at equal pitches, wherein a pitch of the small stator teeth is 1±1/(2 ms) times larger than a pitch of the rotor magnetic pole pairs. The width of the small stator tooth is 37˜47% of the magnetic pole pitch. A depth of the groove formed between the adjacent small stator teeth is more than 15 times larger than the length of the air gap between the stator and the rotor.

Abstract: Disclosed is an inner rotor or outer rotor hybrid stepping motor of 6-phase/6 m-pole type or 10-phase/10 m-pole type. The motor includes a stator that has 6 m or 10 m pieces of magnetic poles and a rotor that is rotatably supported by the stator. Excitation windings are wound around the stator magnetic poles. The stator magnetic pole is divided into two halves in the axial direction, one half has pole teeth being line-symmetric and the other half has pole teeth being asymmetric and deviated from the symmetric pole teeth by ¼ pitch. The positions of the symmetric half and the asymmetric half are inverted between the adjacent magnetic poles. The rotor has a first and second rotor units each of which includes a permanent magnet and first and second rotor magnetic poles around which pole teeth are formed with deviation of ½ pitch.

Abstract: Disclosed is a permanent magnet type twelve-pole stepping motor of an inner rotor type or an outer rotor type. A stator comprises an annular shaped yoke portion, a stator iron-core having twelve stator main poles each having a plurality of small teeth on the tip end thereof and stator coils wound in the stator iron-core as three-phase winding. The stator rotatably supports a hybrid type rotor having a cylindrical permanent magnet that is sandwiched between a pair of rotors each having pole teeth around the circumferential surface to be opposite to the small teeth. Second, third, fourth and fifth harmonic components are removed by composing cogging torque of the respective phases by means of the three-phase twelve-pole construction. Any one harmonic component of the cogging torque among the second to fifth harmonic components is independently erased by making a difference between the small teeth pitch and the rotor teeth pitch, thereby the selected harmonic component is doubly erased.

Abstract: An AC power supply apparatus for obtaining sampled data required for the FFT (Fast Fourier Transformation) by an A/D converter. Since a clock pulse train for forming an output voltage (power supply output) is used as sample clock pulses, sampled data associated with exactly one period can be obtained. This eliminates the need for the window processing. This makes it possible to provide a low cost, error-free apparatus.