An electric motor has a stator mechanically coupled to the rotor by a nutating traction interface, such that during nutation of the rotor with respect to the stator a tilt axis of the rotor progresses about the axis of rotation of the output shaft. The rotor and a surface of the stator bound a dynamic gap across which a magnetic field is produced by electrical activation of the motor to generate a force between the rotor and the stator. The traction interface and the gap are arranged such that, in a plane containing the axis of rotation of the output shaft, the traction interface is angled with respect to the stator surface bounding the gap. The rotor is connected to the output shaft by a tiltable connection such as a gimbal.

An actuator has a first stator with four first poles, a second stator with four second poles aligned with the four first poles, at least one permanent magnet between the first stator and the second stator, four armatures positioned at terminal ends of the aligned four first poles and four second poles and coils wrapped around the first stator and the second stator. A controller selectively applies current to the coils to cause flux created by the at least one permanent magnet to traverse through selective poles of the first stator and the second stator to selectively alter air gap sizes associated with the four armatures.

An actuator has a first stator with four first poles, a second stator with four second poles aligned with the four first poles, at least one permanent magnet between the first stator and the second stator, four armatures positioned at terminal ends of the aligned four first poles and four second poles and coils wrapped around the first stator and the second stator. A controller selectively applies current to the coils to cause flux created by the at least one permanent magnet to traverse through selective poles of the first stator and the second stator to selectively alter air gap sizes associated with the four armatures.

The present invention provides a hydroelectric turbine for generating electricity by extracting power from the tidal flow of water through the turbine, the turbine comprising a shaftless rotor which results in the eccentric rotation of the rotor relative to the stator, which can result in uneven generation of power through differences in the spacing between rim mounted magnets and coils forming a generator of the turbine, the turbine thus employing groupings of equally spaced and serially connected coils.

An electric motor-attached speed reducer includes a first member, an electric motor, a speed reduction mechanism, and a second member. The electric motor is arranged to produce rotational motion with respect to the first member. The speed reduction mechanism is arranged to transfer the rotational motion obtained from the electric motor while reducing the speed thereof. The second member is arranged to rotate relative to the first member at a rotation rate resulting from the speed reduction. A first bearing is arranged between the first and second members. A second bearing is arranged between the first member and a rotor of the electric motor. The speed reduction mechanism includes a flexible third bearing arranged between a non-perfect circular cam and a flexible external gear. The second bearing is arranged to radially overlap with a rotor holder at a first axial position. The third bearing is arranged to radially overlap with the rotor holder at a second axial position different from the first axial position.

A linear drive unit and a machine tool having the linear drive unit, capable of being applied to various applications, while taking into consideration the balance between the thrust force and the cogging of a linear motor. The linear drive unit has a magnetic gap changing mechanism which is configured to change a magnitude of a magnetic gap between a coil and a magnet, by displacing at least one of the coil and the magnet so that the coil and the magnet approach or are separated from each other.

A linear drive unit and a machine tool having the linear drive unit, capable of being applied to various applications, while taking into consideration the balance between the thrust force and the cogging of a linear motor. The linear drive unit has a magnetic gap changing mechanism which is configured to change a magnitude of a magnetic gap between a coil and a magnet, by displacing at least one of the coil and the magnet so that the coil and the magnet approach or are separated from each other.

A wobble plate drive system may include a stator having a central axis, an upper surface perpendicular to the central axis, and a plurality of stator teeth disposed on the upper surface. The system may further include a wobble plate having a wobble axis disposed at a non-zero angle relative to the central axis, a lower wobble surface perpendicular to the wobble axis, and an upper wobble surface perpendicular to the wobble axis. A plurality of lower wobble teeth may be disposed on the lower wobble surface and a plurality of upper wobble teeth may be disposed on the upper wobble surface. The system may include an output gear having an output axis substantially aligned with the central axis and a lower surface perpendicular to the output axis. A plurality of output teeth may be disposed on the lower surface. The wobble plate may be configured to rotate as it nutates around the stator.

An electric motor has a stator mechanically coupled to the rotor by a nutating traction interface, such that during nutation of the rotor with respect to the stator a tilt axis of the rotor progresses about the axis of rotation of the output shaft. The rotor and a surface of the stator bound a dynamic gap across which a magnetic field is produced by electrical activation of the motor to generate a force between the rotor and the stator. The traction interface and the gap are arranged such that, in a plane containing the axis of rotation of the output shaft, the traction interface is angled with respect to the stator surface bounding the gap. The rotor is connected to the output shaft by a tiltable connection such as a gimbal.

An electric motor has a stator mechanically coupled to the rotor by a nutating traction interface, such that during nutation of the rotor with respect to the stator a tilt axis of the rotor progresses about the axis of rotation of the output shaft. The rotor and a surface of the stator bound a dynamic gap across which a magnetic field is produced by electrical activation of the motor to generate a force between the rotor and the stator. The traction interface and the gap are arranged such that, in a plane containing the axis of rotation of the output shaft, the traction interface is angled with respect to the stator surface bounding the gap. The rotor is connected to the output shaft by a tiltable connection such as a gimbal.