An electric power generation and brake device disposed on a shaft includes: a wheel, a stator unit and a brake unit; the wheel comprising: an outer ring disposed around an edge of the wheel, an inner ring on the wheel and configured between the outer ring and an axis of the wheel, and a plurality of permanent magnets configured on one surface of the outer ring; the stator unit, comprising: a stator body, a plurality of first serrated portions disposed around an outer peripheral surface of the stator body, and a plurality of electric generating coils; the brake unit, comprising: a brake body fixed on the shaft or the stator body and configured between the inner ring and the axis of the wheel, a plurality of second serrated portions, and a plurality of brake coils; with the arrangement to resist vibration and reduce noise.

A stator core has first, second, and third pole teeth disposed circumferentially and projecting radially outward, the first pole teeth face rotor magnets and have symmetric tooth tips, the second and third pole teeth are circumferentially disposed adjacent to the first pole teeth and have asymmetric tooth tips, and a distance between the tooth tips of the second and third pole teeth is smaller than a distance between the tooth tips of the first and second pole teeth and the distance between the tooth tips of the first and third pole teeth. This apparently reduces the facing ratio between the stator pole teeth and the rotor magnetic poles and increases the cogging torque while preventing increase in cost and reduction in workability.

A rotating electric machine includes: a rotation shaft; a bearing retaining the rotation shaft; an electromagnetic brake that is provided on an outer peripheral side of the rotation shaft and is located between the bearing and a rotor, the electromagnetic brake locking the rotation shaft during non-excitation and releasing the locking during excitation; a magnetic-flux shielding unit provided on an outer peripheral side of the electromagnetic brake; and a slidable contact unit that is provided so as to be in contact with the magnetic-flux shielding unit and the rotation shaft and comes into contact with the magnetic-flux shielding unit and the rotation shaft at least at two locations on the bearing side and the rotor side, wherein a magnetic field generated from the electromagnetic brake forms a closed circuit through the rotation shaft, the magnetic-flux shielding unit, and the slidable contact unit.

A rotating electric machine includes: a rotation shaft; a bearing retaining the rotation shaft; an electromagnetic brake that is provided on an outer peripheral side of the rotation shaft and is located between the bearing and a rotor, the electromagnetic brake locking the rotation shaft during non-excitation and releasing the locking during excitation; a magnetic-flux shielding unit provided on an outer peripheral side of the electromagnetic brake; and a slidable contact unit that is provided so as to be in contact with the magnetic-flux shielding unit and the rotation shaft and comes into contact with the magnetic-flux shielding unit and the rotation shaft at least at two locations on the bearing side and the rotor side, wherein a magnetic field generated from the electromagnetic brake forms a closed circuit through the rotation shaft, the magnetic-flux shielding unit, and the slidable contact unit.

A propeller alignment device is described. The propeller alignment device can include a second retainer attached to a propeller and a motor. The propeller alignment device can also include a first retainer that does not rotate, but that is aligned with the second retainer. The first retainer can include two or more magnets oppositely orientated relative to each other. The second retainer can also include two or more magnets oppositely orientated relative to each other. As the second retainer rotates relative to the first retainer, the magnets may alternatingly align with each other. In the absence of a current applied to the motor, the magnets may magnetically bias the second retainer into a predetermined orientation relative to the first retainer. The predetermined orientation can be predetermined to correspond to an alignment of the propeller that is desirable (e.g., that minimizes aerodynamic drag on the propeller).

The invention provides a brushless motor. A stator 16 of the brushless motor has a stator core 17 provided with a plurality of salient poles 18 arranged in its a circumferential direction, and a winding wire 20 wound around the plurality of salient poles 18 through an insulator 19. A rotor 22 of the brushless motor has a tubular rotor yoke 23 arranged to surround the stator 16, an annular magnet for detent torque 25 arranged in an inner peripheral portion of the winding wire 20 on the stator core 17 and surrounding the shaft 15, and a magnetic member 27 coupled to an interior surface of a ceiling portion of the rotor yoke 23 to be opposed to the magnet for detent torque 25, and surrounding the shaft 15.

The invention provides a brushless motor. A stator 16 of the brushless motor has a stator core 17 provided with a plurality of salient poles 18 arranged in its a circumferential direction, and a winding wire 20 wound around the plurality of salient poles 18 through an insulator 19. A rotor 22 of the brushless motor has a tubular rotor yoke 23 arranged to surround the stator 16, an annular magnet for detent torque 25 arranged in an inner peripheral portion of the winding wire 20 on the stator core 17 and surrounding the shaft 15, and a magnetic member 27 coupled to an interior surface of a ceiling portion of the rotor yoke 23 to be opposed to the magnet for detent torque 25, and surrounding the shaft 15.

A propeller alignment device is described. The propeller alignment device can include a second retainer attached to a propeller and a motor. The propeller alignment device can also include a first retainer that does not rotate, but that is aligned with the second retainer. The first retainer can include two or more magnets oppositely orientated relative to each other. The second retainer can also include two or more magnets oppositely orientated relative to each other. As the second retainer rotates relative to the first retainer, the magnets may alternatingly align with each other. In the absence of a current applied to the motor, the magnets may magnetically bias the second retainer into a predetermined orientation relative to the first retainer. The predetermined orientation can be predetermined to correspond to an alignment of the propeller that is desirable (e.g., that minimizes aerodynamic drag on the propeller).

A motor having an electromagnetic brake is provided to ensure a braking torque even when power is off. The motor assembly comprises a drive motor and an electromagnetic brake. A thrust generating mechanism translates rotational motion of a brake motor to linear motion to generate thrust force for moving any one of brake stator and brake rotor of the electromagnetic brake thereby maintaining frictional contact therebetween to stop rotation of a motor shaft.

A motor having an electromagnetic brake is provided to ensure a braking torque even when power is off. The motor assembly comprises a drive motor and an electromagnetic brake. A thrust generating mechanism translates rotational motion of a brake motor to linear motion to generate thrust force for moving any one of brake stator and brake rotor of the electromagnetic brake thereby maintaining frictional contact therebetween to stop rotation of a motor shaft.