A dynamoelectric machine comprises: a stator that comprises a plurality of stator poles arranged around a stator surface of revolution with a stator axis for the stator surface of revolution; at least one rotor that comprises a plurality of permanent rotor magnets arranged around a rotor surface of revolution with a rotor axis for the rotor surface of revolution that is coincident with the stator axis and with the rotor surface of revolution adjacent the stator surface of revolution; a drive shaft with a drive shaft axis of rotation that is substantially coincident with the stator axis coupled to the rotor for rotating the rotor relative to the stator about the drive shaft axis of rotation; and a at least one actuator for axially displacing the rotor surface of revolution along the drive shaft relative to the stator surface of revolution to change magnetic flux interaction between the stator poles and the rotor magnets; wherein at least one of the surfaces of revolution tilts with respect to the drive shaft axis of rotation.

A linear actuator is provided with an integral permanent magnet, brushless motor capable of axial, self adjustment of the rotor position within the stator for field weakening. Axial displacement of the rotor within the stator allows for significantly improved speed performance from aligned rotor/stator components during light axial loading. Upon contact with a load, the screw and nut, as an integral part of the motor rotor, self align to fully engage within the stator for generation of high forces with minimal current. This axial shift can further be used as a high precision, low cost measure of the force applied for quality assurance purposes.

A brushless permanent magnet electric machine with a fixed radial air gap is operated to a much higher speed than normal maximum speed by the reduction in effective magnet pole strength. Permanent magnets are supported on the inner surface of an axially movable cylindrical shell. A plurality of magnetic poles provided with wire coils are supported on a stationary cylindrical member cooperate with the permanent magnets on the axially movable cylindrical shell to either cause, or react to, rotation of the axially movable cylindrical shell. The axially movable cylindrical shell and cylindrical member are coaxial. The cylindrical shell is axially movable with respect to the cylindrical member.

A rotor-stator structure for electrodynamic machinery is disclosed to, among other things, minimize magnetic flux path lengths and to eliminate back-iron for increasing torque and/or efficiency per unit size (or unit weight) and for reducing manufacturing costs. In one embodiment, an exemplary rotor-stator structure can comprise a shaft defining an axis of rotation, and a rotor on which at least two substantially conical magnets are mounted on the shaft. The magnets include conical magnetic surfaces facing each other and confronting air gaps. In some embodiments, substantially straight field pole members can be arranged coaxially and have flux interaction surfaces formed at both ends of those field poles. Those surfaces are located adjacent to the confronting conical magnetic surfaces to define functioning air gaps. Current in coils wound on the field poles provide selectable magnetic fields that interact with magnet flux in flux interaction regions to provide torque to the shaft.

A rotor-stator structure for electrodynamic machinery is disclosed to, among other things, minimize magnetic flux path lengths and to eliminate back-iron for increasing torque and/or efficiency per unit size (or unit weight) and for reducing manufacturing costs. In one embodiment, an exemplary rotor-stator structure can comprise a shaft defining an axis of rotation, and a rotor on which at least two magnets are mounted on the shaft. The two magnets can be cylindrical or conical magnets having magnetic surfaces that confront air gaps. In some embodiments, substantially straight field pole members can be arranged coaxially and have flux interaction surfaces formed at both ends of those field poles. Those surfaces are located adjacent to the confronting magnetic surfaces to define functioning air gaps, which are generally curved in shape.