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US 6,713,904 B2Granted
Linear voice coil actuator with compensating coils
AssigneeBEI Technologies, Inc.
InventorMikhail Godkin
Life of this patent
Estimating the term…
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.
Claims15
A voice coil actuator comprising
- a core having an axis;
- a permanent magnet having a longitudinal axis, and positioned so that the longitudinal axis of the permanent magnet is substantially parallel to the axis of the core;
- a moving coil positioned to interact with the permanent magnet along the axis of the core;
- and
- a compensating coil positioned to interact with the moving coil, wherein a magneto-motive force in the compensating coil is controlled as a function of a position of the moving coil;
- wherein the compensating coil is positioned about the core;
- wherein the compensating coil extends along substantially the entire length of the core;
- and
- wherein the permanent magnet is positioned with respect to the core to define a cavity between the core and an end of the permanent magnet;
- and further wherein a second compensating coil is positioned in the cavity.
7 more elements
A voice coil actuator comprising
- a core having an axis;
- a permanent magnet having a longitudinal axis, and positioned so that the longitudinal axis of the permanent magnet is substantially parallel to the axis of the core;
- a moving coil positioned to interact with the permanent magnet along the axis of the core;
- and
- a compensating coil positioned to interact with the moving coil, wherein a magneto-motive force in the compensating coil is controlled as a function of a position of the moving coil;
- wherein the permanent magnet is positioned with respect to the core to define a cavity between the core and an end of the permanent magnet;
- and
- further wherein the compensating coil is positioned in the cavity;
- wherein a second cavity is defined at another end of the permanent magnet between the permanent magnet and the core, and further wherein a further compensating coil is positioned in the second cavity;
- further including a core compensating coil positioned about the core.
7 more elements
An actuator comprising:
- a core;
- a permanent magnet having a longitudinal axis, and positioned so that the longitudinal axis of the permanent magnet is substantially parallel to an axis of the core;
- a moving coil positioned to interact with the permanent magnet along the axis of the core;
- and
- a plurality of compensating coils positioned to interact with the moving coil and controlled as a function of a position of the moving coil, including
- a core compensating coil positioned about the core;
- a first compensating coil positioned in a cavity formed between an end of the permanent magnet and the core.
4 more elements
An actuator comprising
- a core;
- a permanent magnet having a longitudinal axis, and positioned so that the longitudinal axis of the permanent magnet is substantially parallel to an axis of the core;
- a moving coil positioned to interact with the permanent magnet along the axis of the core;
- and
- a compensating coil positioned to interact with the moving coil and having a magneto-motive force which is controlled as a function of a position of the moving coil;
- wherein the compensating coil is positioned about the core;
- wherein the compensating coil extends along substantially the entire length of the core;
- and
- wherein the permanent magnet is positioned with respect to the core to define a cavity between the core and an end of the permanent magnet;
- and
- further wherein a second compensating coil is positioned in the cavity.
8 more elements
An actuator comprising
- a core;
- a permanent magnet having a longitudinal axis, and positioned so that the longitudinal axis of the permanent magnet is substantially parallel to an axis of the core;
- a moving coil positioned to interact with the permanent magnet along the axis of the core;
- and
- a compensating coil positioned to interact with the moving coil and having a magneto-motive force which is controlled as a function of a position of the moving coil;
- wherein the permanent magnet is positioned with respect to the core to define a cavity between the core and an end of the permanent magnet;
- and further wherein the compensating coil is positioned in the cavity;
- wherein a second cavity is defined at another end of the permanent magnet between the permanent magnet and the core, and further wherein a further compensating coil is positioned in the second cavity;
- further including a core compensating coil positioned about the core.
6 more elements
Dependencies are inferred from the claim text.