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Abstract

An electromagnetic active vibration actuator configuration combines two modes of operation to obtain the advantages of long stroke and linearity of voice coil type actuators and high efficiency of dual-gap solenoid type actuators. A coaxial stator shell surrounds an axially vibratable armature. Either the stator or the armature can carry one or more coils and/or permanent magnets, however usually the magnets are located on the armature for their contribution to vibrating mass. Alternate coils and alternate magnets are made opposite in polarity, the stator armature pole pieces being held symmetrically staggered relative to the stator pole pieces by end springs or flexures that allow axial vibration when AC is applied to the coils. Two different types of flux loop paths are associated with each pair of permanent magnet prominent poles: a voice-coil-effect flux loop path including two air gaps, each traversing a coil, that remain relatively constant in separation distance and permeability under vibration, and a solenoid-effect loop flux path traversing a pair of gaps in series flanking a coil prominent pole, that vary in separation distance and permeability in a complementary manner under vibration in the manner of a solenoid type actuator. These two magnetic modes operate in a cooperative additive efficient manner. Multiples of a typical magnet/coil pair can be easily tandemed using common building block component elements, typically being made to have in total an odd number of prominent poles. Wide flexibility is provided in design and manufacture to customize the performance of the actuator by manipulating the proportion of voice coil effect and solenoid effect along with the mechanical spring effect and the vibrating mass.

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First Claim