Electric motor

An electric motor comprising:

• an output shaft defining an axis of rotation;
• a first nutating rotor coupled to the output shaft at a tiltable connection;
• a first stator disposed adjacent the first nutating rotor to define a dynamic air gap, the first stator having multiple windings each configured to generate a magnetic field to draw a respective side of the first nutating rotor toward the first stator, to cause the first nutating rotor to nutate with respect to the first stator in response to sequential activations of the multiple windings, progressively tilting the tiltable connection,
• wherein the dynamic air gap is bounded by an outer circumferential surface of the first nutating rotor, such that magnetic coupling between the first nutating rotor and the first stator is principally radial, and
• wherein the first stator is mechanically coupled to the first nutating rotor by a first nutating traction interface such that during nutation of the first nutating rotor with respect to the first stator a respective tilt axis of the rotor progresses about an axis of rotation of the output shaft, wherein the first nutating traction interface comprises a series of rotor gear teeth configured to axially mesh with a series of stator gear teeth,
• a second nutating rotor rotationally coupled to the output shaft;
• and
• a second stator mechanically coupled to the second nutating rotor by a second nutating traction interface, such that during nutation of the second nutating rotor with respect to the second stator a tilt axis of the second nutating rotor progresses to define a conical surface with respect to the axis of rotation of the output shaft,
• wherein the second nutating rotor and a surface of the second stator are bound a radial gap across which a second magnetic field is produced by electrical activation of the electric motor to generate a force between the second nutating rotor and the second stator.

A method of operating an electric motor, the method comprising:

• activating a first coil of a stator disposed adjacent a nutating rotor to define a dynamic air gap bounded by an outer circumferential surface of the nutating rotor, such that magnetic coupling between the nutating rotor and stator is principally radial, the nutating rotor coupled to an output shaft of the electric motor at a tiltable connection;
• activating a second coil of the stator, the second coil spaced circumferentially from the first coil;
• and
• activating a third coil of the stator, the third coil spaced circumferentially from both the first and second coils, with the second coil disposed between the first and third coils,
• wherein sequential activation of the first coil, the second coil, and third coil, causes the nutating rotor to nutate about an output shaft axis and thereby to turn the output shaft,
• wherein the stator is mechanically coupled to the nutating rotor by a nutating traction interface such that during nutation of the nutating rotor with respect to the stator a respective tilt axis of the nutating rotor progresses about an axis of rotation of the output shaft, wherein the traction interface comprises a series of rotor gear teeth axially meshed with a series of stator gear teeth,
• wherein the nutating rotor is a first nutating rotor, the stator is a first stator, and the nutating traction interface is a first nutating traction interface, and
• wherein the electric motor further comprises:
• a second nutating rotor rotationally coupled to the output shaft;
• and
• a second stator mechanically coupled to the second nutating rotor by a second nutating traction interface, such that during nutation of the second nutating rotor with respect to the second stator a tilt axis of the second nutating rotor progresses to define a conical surface with respect to the axis of rotation of the output shaft,
• wherein the second nutating rotor and a surface of the second stator are bound a radial gap across which a magnetic field is produced by electrical activation of the electric motor to generate a force between the second nutating rotor and the second stator.

A method of operating an electric motor, the method comprising:

• activating a first coil of a stator disposed adjacent a nutating rotor to define a dynamic air gap bounded by an outer circumferential surface of the rotor, such that magnetic coupling between the rotor and stator is principally radial, the nutating rotor coupled to an output shaft of the electric motor at a tiltable connection;
• activating a second coil of the stator, the second coil spaced circumferentially from the first coil;
• and then
• activating a third coil of the stator, the third coil spaced circumferentially from both the first and second coils, with the second coil disposed between the first and third coils,
• wherein sequential activation of the first coil, the second coil, and third coil, causes the rotor to nutate about an output shaft axis and thereby to turn the output shaft, and
• wherein the stator is mechanically coupled to the nutating rotor by a nutating traction interface such that during nutation of the rotor with respect to the stator a respective tilt axis of the rotor progresses about an axis of rotation of the output shaft, wherein the nutating traction interface comprises a series of rotor gear teeth axially meshed with a series of stator gear teeth, and
• wherein the output shaft defines a lubrication port arranged to direct a flowable lubricant to the nutating traction interface.