The application relates to a magnetic biasing assembly. The magnetic biasing assembly comprises an outer part, having a first permanent magnet and an outer ferromagnetic annulus disposed radially outwardly of the first permanent magnet; and an inner part, having a second permanent magnet and an inner ferromagnetic annulus disposed radially inwardly of the second permanent magnet. The outer and inner parts are rotatable relative to each other about an axis to move the inner and outer parts into and out of an equilibrium position with each other. When the inner and outer parts are moved out of the equilibrium position, the first and second permanent magnets are arranged to generate a magnetic restoring moment between the inner and outer parts in a direction towards the equilibrium position.

An electric machine assembly includes a rotor formed from one or more magnetically conductive sheets having elongated magnetic flux barriers separated from each other in radial directions that radially extend away from an axis of rotation of the rotor. The magnetic flux barriers are separated from each other by magnetic flux carrier portions of the one or more magnetically conductive sheets. The assembly also includes a non-magnetic post coupled with the magnetic flux carrier portions of the one or more magnetically conductive sheets on opposite sides of at least one of the magnetic flux barriers. The non-magnetic post is elongated in the radial directions from a first magnetic flux carrier portion to a second magnetic flux carrier portion of the magnetic flux carrier portions on the opposite sides of the at least one magnetic flux barrier.

An approach to a reduced-head hard disk drive (HDD) involves an actuator subsystem that includes a ball screw cam assembly wherein the number of starts of a multi-start screw equals the number of balls riding in a corresponding start. A stepper motor may be disposed within the screw, to drive rotation of the screw, which drives translation of an actuator arm assembly so that a corresponding pair of read-write heads can access different magnetic-recording disks of a multiple-disk stack. The actuator subsystem may further include a cam locking mechanism for coupling and decoupling the actuator arm with a coil support structure and corresponding voice coil, so that the cam mechanism is able to move under the control of a voice coil motor when input/output operations are performed and is able to move the actuator arm assembly during translation operations.

An approach to a reduced-head hard disk drive (HDD) involves an actuator subsystem that includes a ball screw cam assembly wherein the number of starts of a multi-start screw equals the number of balls riding in a corresponding start. A stepper motor may be disposed within the screw, to drive rotation of the screw, which drives translation of an actuator arm assembly so that a corresponding pair of read-write heads can access different magnetic-recording disks of a multiple-disk stack. The actuator subsystem may further include a cam locking mechanism for coupling and decoupling the actuator arm with a coil support structure and corresponding voice coil, so that the cam mechanism is able to move under the control of a voice coil motor when input/output operations are performed and is able to move the actuator arm assembly during translation operations.

An approach to a reduced-head hard disk drive (HDD) involves an actuator subsystem that includes a ball screw cam assembly wherein the number of starts of a multi-start screw equals the number of balls riding in a corresponding start. A stepper motor may be disposed within the screw, to drive rotation of the screw, which drives translation of an actuator arm assembly so that a corresponding pair of read-write heads can access different magnetic-recording disks of a multiple-disk stack. The actuator subsystem may further include a cam locking mechanism for coupling and decoupling the actuator arm with a coil support structure and corresponding voice coil, so that the cam mechanism is able to move under the control of a voice coil motor when input/output operations are performed and is able to move the actuator arm assembly during translation operations.

A stepper motor includes: a rotor including a rotor core and a permanent magnet, the rotor core including a plurality of teeth; and a stator arranged around the rotor while being spaced apart from the rotor and including a plurality of magnetic pole teeth, the magnetic pole teeth including a plurality of teeth and projecting toward the rotor. A winding is wound around every other magnetic pole tooth. A phase of the teeth of the magnetic pole teeth with no winding therearound is shifted from a phase of the teeth of the other magnetic pole teeth.

A stepper motor includes: a rotor including a rotor core and a permanent magnet, the rotor core including a plurality of teeth; and a stator arranged around the rotor while being spaced apart from the rotor and including a plurality of magnetic pole teeth, the magnetic pole teeth including a plurality of teeth and projecting toward the rotor. A winding is wound around every other magnetic pole tooth. A phase of the teeth of the magnetic pole teeth with no winding therearound is shifted from a phase of the teeth of the other magnetic pole teeth.

To manufacture a permanent magnetic motor having saliency at a low cost, a permanent magnet motor includes a stator provided with an armature winding configured to form a plurality of phases, a rotor having a surface facing the stator, the rotor including a permanent magnet disposed to face the stator, the permanent magnet having a plurality of magnetic poles arranged in a circumferential direction of the rotor, and a conductive member made of a conductive material and disposed on the surface of the rotor facing the stator.

A sequential actuator for a radio frequency switch includes a rotor designed to be rotated in a designated rotational direction of the actuator and a stator defining with the rotor when the stator is energized an active torque curve of the rotor having asymmetric positive and negative torque curve portions. Magnetic elements are distributed between the rotor and the stator and define a detent torque curve of the rotor. In some examples, when the stator is energized, the rotor undergoes a first rotation from a position of partial angular overlap of a first rotor magnetic element with a first stator electromagnet to a position of angular alignment of the first rotor magnetic element with the first stator electromagnet. Upon reaching this angular position, a second rotor magnetic element has a partial angular overlap with a second stator electromagnet and the rotor further undergoes a second rotation to another position of angular alignment of the second rotor magnetic element with the second stator electromagnet.

A sequential actuator for a radio frequency switch includes a rotor designed to be rotated in a designated rotational direction of the actuator and a stator defining with the rotor when the stator is energized an active torque curve of the rotor having asymmetric positive and negative torque curve portions. Magnetic elements are distributed between the rotor and the stator and define a detent torque curve of the rotor. In some examples, when the stator is energized, the rotor undergoes a first rotation from a position of partial angular overlap of a first rotor magnetic element with a first stator electromagnet to a position of angular alignment of the first rotor magnetic element with the first stator electromagnet. Upon reaching this angular position, a second rotor magnetic element has a partial angular overlap with a second stator electromagnet and the rotor further undergoes a second rotation to another position of angular alignment of the second rotor magnetic element with the second stator electromagnet.