USA As Represented by Secretary of the Navy

Lucent Technologies Inc.

General Dynamics Advanced Technology Systems, Inc.

John E Miesner

George Gustave Zipfel, Jr

Example embodiments provide a voice coil array speaker comprising a speaker assembly, a coil assembly, and a magnet assembly. The speaker assembly may comprise a speaker frame, a stationary base plate, a diaphragm configured to be capable of axial movement, a heat conducting front plate connected to the diaphragm, and thermal bridges configured to conduct heat from the heat conducting front plate to the speaker frame. The coil assembly may be connected to the heat conducting front plate, the coil assembly may comprise an array of coils wound around coil formers. The magnet assembly may be attached to the stationary base plate, the magnet assembly may comprise an array of laterally and vertically polarized magnets in contact with flux concentrators. The array of coils may be connected such that the direction of current flow alternates between clockwise and counterclockwise moving laterally across the array.

Voice coil array speaker

The invention relates to saddle coil winding apparatus, methods of manufacturing saddle coils, and saddle coils produced using the winding apparatus and/or manufacturing methods. The saddle coil winding apparatus and methods of manufacturing beneficially reduce or eliminate the stretching of electrical wires, and do not cause the electrical wires to slide past each other. The saddle coils produced using the winding apparatus and/or manufacturing methods may have electrical leads provided on the outside of the coil.

Methods for manufacturing saddle coils

Example embodiments provide a voice coil apparatus that may comprise corner posts, a voice coil wound directly on to the corner posts, the coil forming straight sides between the corner posts due to winding tension, and a center flux return having straight sides and having a continuous plated layer of electrically conductive material, the center flux return being made of a ferromagnetic material. The voice coil apparatus may further comprise rubber mounts at corners of the center flux return and supporting the corner posts, and configured to provide high lateral compression stiffness and low axial shear stiffness in order to facilitate axial movement of the voice coil. In example embodiments, the voice coil lacks a coil former. The rubber mounts and the corner posts establish a uniform offset. The continuous plated layer serves as a shorted turn.

Voice coil and speaker without coil former

Electromagnetic actuators are provided, which generate bidirectional linear force output without magnetic bias from current or permanent magnets. Systems and methods based on the electromagnetic actuators are also provided.

Linearized pull-pull electromagnetic actuators, systems, and methods

Electromagnetic inertial force generators are provided, which include radially polarized permanent magnets providing bias flux across axial gaps to combine with axial coil flux to linearize the actuator output. Coil cooling in the electromagnetic inertial force generators is improved by embedding the coils in the stationary portion of the actuator, allowing for direct transfer of coil heat, and reducing oscillating stresses on coil leads.

Linear electromagnetic actuator with improved coil cooling

An electromagnetic inertial force generator is provided, which includes radially polarized permanent magnets providing bias flux across axial gaps to combine with axial coil flux to linearize flux output. An array of components is integrated into a single structure that is more compact and lighter than a monolithic force generator, providing the same level of performance while using less permanent magnet material.

Electromagnetic arrays

Electromagnetic actuators are provided, which generate bidirectional linear force output without magnetic bias from current or permanent magnets. Systems and methods based on the electromagnetic actuators are also provided. In particular, an electromagnetic actuator having a shaft, an axial bearing, coil assembly, top and bottom stationary flux returns, and top and bottom magnetic flux sensors to measure flux crossing the respective top and bottom axial air gaps.

Inertial actuators are provided, which use a one-dimensional or a two-dimensional voice coil array to achieve the same force output performance as a monolithic actuator. The voice coil arrays use less permanent magnet and flux conducting material, and have a lower inductance, while achieving increased frequency bandwidth.

Voice coil arrays

Exemplary practice of the present invention provides a magnetostrictive actuator characterized by linear force output and uniform magnetic biasing. A center bias magnet drives flux through series magnetostrictive bars in opposite directions while surrounding drive coils apply flux in the same direction through the bars. The net response is substantially linear with respect to the drive coil current. A second parallel set of magnetostrictive bars completes the flux path and adds to the actuator output force. Flux leakage between the parallel bars is compensated by a ferromagnetic shunt or by a tapered magnet providing uniform flux density down the length of the magnetostrictive bars. The closed flux path allows magnetic shielding of the entire actuator, if desired.

Linear magnetostrictive actuator

Exemplary practice of the present invention provides a magnetostrictive actuator characterized by linear force output and uniform magnetic biasing. A center bias magnet combined with a flux transfer tube produces a uniform magnetic bias down the length of a magnetostrictive component. Depending on the inventive embodiment, the magnetostrictive component may include one magnetostrictive element or a pair of collinear magnetostrictive elements. A center bias magnet, in combination with a flux transfer tube, drives magnetic flux through the magnetostrictive component (e.g., a series of magnetostrictive rods) in opposite directions, while surrounding drive coils apply flux in the same direction through the magnetostrictive component. The net response is substantially linear with respect to the drive coil current. The flux transfer tube applies distributed magnetic flux to the magnetostrictive component at a rate that ensures uniform magnetic flux density down the length of the magnetostrictive component.

Magnetostrictive actuator with center bias

An electromagnetic inertial force generator provides a linear output with improved compactness and reliability because it has no radial gaps and only one pair of axial gaps. Radial permanent magnet rings are directly in contact with inner and outer flux cylinders to provide magnetic bias. The magnetic bias flux flows across two axial air gaps to a supporting flux return structure. A current conducting coil drives magnetic flux across the same axial air gaps. The magnetic bias flux is in opposite directions across the two air gaps, while the coil flux across the two gaps is in the same direction. The combination of bias flux and coil flux cancels in one gap and adds in the other gap, producing a net force on an inertial mass and an equal and opposite force on the supporting structure. The resulting force is linear with current through the drive coil.

Linear electromagnetic actuator

The invention is an electromagnetic inertial force generator that provides a linear output with improved compactness and reliability because it has no radial gaps and only on pair of axial gaps. Radial permanent magnet rings are directly in contact with inner and outer flux cylinders to provide magnetic bias. The magnetic bias flux flows across two axial air gaps to a supporting flux return structure. A current conducting coil drives magnetic flux across the same axial air gaps. The magnetic bias flux is in opposite directions across the two air gaps while the coil flux across the two gaps is in the same direction. The combination of bias flux and coil flux cancels in one gap and add in the other gap producing a net force on an inertial mass and an equal and opposite force on the supporting structure. The resulting force is linear with current through the drive coil.

An exemplary magnetic flux sensor in accordance with the present invention is characterized by an electrical output that is proportional to the total static and dynamic flux passing normally through a large area. An oscillating electrical current passing down a conducting area produces Lorentz forces, which are transferred to piezoelectric areas. The piezoelectric areas produce electrical voltage at the oscillation frequency whereby amplitude is proportional to the total magnetic flux passing normally through the conducting area. Demodulating the voltage provides an electrical signal with high sensitivity, dynamic range, and noise immunity.

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Fairfax Station, VA, United States of America

John E Miesner