Abstract: A linear voice coil actuator is disclosed which includes field subassemblies each including a field blank, and in which at least a one of the field subassemblies includes magnets of alternating polarity positioned on the field blank to form interleaved-magnetic circuits in a direction of motion of the linear voice coil actuator. The field subassemblies are positioned with respect to one another to form a gap between the field subassembly having the magnets, and another of the field subassemblies. Also included is a coil assembly that includes coils positioned in a plane within the gap, wherein the plane is substantially parallel to the direction of motion of the linear voice coil actuator.

Abstract: Disclosed is a linear voice coil actuator having a latching feature, the actuator having a coil assembly, a field assembly, a magnetic structure positioned in the coil assembly, and a stop which limits the position of the magnetic structure with respect to the field assembly when the coil is not energized. The coil assembly has a coil base and a coil located in a cavity in the coil base. The field assembly preferably has an axially magnetized cylindrical magnet, a soft pole piece, and a soft magnetic housing. Preferably the magnetic structure is a magnetic plate positioned coaxially with the axis of magnetization of the magnet and having a diameter or a thickness which is selected to set a latching force between the plate and the magnet when the coil is not energized.

Abstract: A stack assembly is disclosed of the type used in linear brushless DC motors, the stack assembly having a base portion, a plurality of teeth extending from the base portion and about which the windings can be positioned, and in which the plurality of teeth are spaced apart from each other so as to define slot openings at ends of and between adjacent teeth, and magnetic material shaped and positionable to enclose one or more of the slot openings between adjacent teeth. Also disclosed is a mounting bracket positionable along the back iron of the stack assembly and shaped so that the ends of the mounting bracket engage with the ends of the stack assembly.

Abstract: A voice coil actuator is disclosed which provides a proportional solenoid type characteristic and in which first and second magnets are positioned at different ends of a first soft magnetic pole piece and magnetized in opposite directions, the first soft magnetic pole piece having a length greater than the length of the first magnet and the length of the second magnet. A coil having a length less than the lengths of the first soft magnetic pole piece is positioned for travel along an axis common to the first soft magnetic pole piece and first and second magnets, and a structure provides a magnetic path between free ends of the first and second magnets.

Abstract: A linear motion device is disclosed which includes an armature assembly, and a field assembly which includes a plurality of permanent magnets each having a length, and a plurality of pole pieces each having a length. The ratio between the length of the plurality of permanent magnets and the length of the plurality of pole pieces is tailored to achieve a constant force versus stroke characteristic, when sinusoidal commutation is used.

Abstract: An actuator is provided in which one or more separate compensating coils are employed to alter the distribution of the magnetic flux density in the air gap to produce a substantially constant force throughout the stroke; and in which current in the separate compensating coils can be adjusted with the stroke using separate power supplies and position feedback.

Abstract: An embodiment has an armature member having a linear core with transverse open slots distributed over its length. Two sets of coils are disposed in the slots and distributed over the length of the core preferably in an overlapping interlaced pattern such that when the sets of coils, or corresponding sub-sets of the coils, are simultaneously energized the magnetic forces produced by one augments the forces produced by the other to produce a greater total force. The armature member also has disposed on opposite sides of the core and parallel to the core a pair of linear commutators. A field member has a carriage which travels rectilinearly along the core between the commutators. Dual sets of brushes are linearly mounted on the carriage at opposite sides to communicate with the commutators. The dual sets of coils can be energized in parallel or in series via the brush/commutator contacts or each set of coils can be energized separately by independently powering the set's corresponding set of brushes.

Abstract: According to a preferred embodiment of the present invention, a double-ended moving coil linear actuator is provided comprising a cylindrical core and a hollow shell disposed around the core to define an annular space between the inner wall of the shell and the outer wall of the core. A non-magnetic spacer is mounted in the annular space to divide the annular space into first and second annular cavities, each of the cavities having a closed end adjacent the spacer and an open end. A first set of magnets is mounted within the first annular cavity to define a first magnetic circuit. A second set of magnets is mounted within the second annular cavity to define a second magnetic circuit. The magnets of these two magnetic circuits are sized and arranged to define a third "interleaved" magnetic circuit which is created by the interaction of the first two circuits. Each of the first two magnetic circuits has a dual-winding coil assembly associated with it.

Abstract: A brushless alternator is disclosed having a stationary field coil and core surrounded by a stationary stator coil and core with a cylindrical air gap being defined therebetween. A rotor assembly is fixed to a rotatable shaft and has interweaved separate magnetic finger assemblies joined together by a non-magnetic ring wherein these fingers are rotated in the cylindrical gap. The stator and field cores are radially disposed with respect to the rotatable shaft. The field core axially extends beyond the effective axial length of the field coil and provides at an axial position beyond the effective axial length of the field coil, at least one low reluctance axial flux gap between the field core and the magnetic fingers. This flux gap conducts a substantial portion of the flux created by the field coil. The field core also serves as a shaft bearing retainer and has a bearing grease reservoir comprising a cylindrical recess adjacent the shaft bearing.

Abstract: The permanent magnet is mounted within the coil in engagement with the magnetic frame so when the coil is energized by a pulse of DC voltage of polarity giving a coil flux aiding the magnet the plunger is actuated against the bias of the spring to move the plunger close enough to the magnet to be retained. A pluse of opposite polarity gives a coil flux opposing the magnet flux so the holding force is less than the spring force and the plunger is moved to its inactive position.