Extended multiple gap motors for electromagnetic transducers

Abstract

An electromagnetic transducer includes an electromagnetic dual-coil or multi-coil driver having at least one spacer member placed between at least two permanent magnets. The inclusion of at least one spacer member increases the axial dimension of the magnetic assembly of the driver so that the magnetic gaps in a dual-coil or multi-coil driver are moved farther apart than would occur with a corresponding electromagnetic driver using a permanent magnet instead of two permanent magnets separated by a spacer member.

Description

BRIEF DESCRIPTION OF THE FIGURES

The invention may be better understood by referring to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.

FIG. 1 is a top perspective view of an example of a loudspeaker of the invention.

FIG. 2 is a bottom perspective view of the loudspeaker illustrated in FIG. 1.

FIG. 3 is a cross-sectional view of the loudspeaker illustrated in FIGS. 1 and 2, taken along line A-A, according to one example of an implementation of the invention.

FIG. 4 is a cut away view of a portion of the loudspeaker illustrated in FIG. 3.

FIG. 5 is a top plan view of a stacked arrangement of components of a magnetic assembly according to an example of an implementation of the invention.

FIG. 6 is a side cross-sectional view of the stacked arrangement illustrated in FIG. 6 taken along line B-B.

FIG. 7 is a perspective cross-sectional view of the stacked arrangement illustrated in FIG. 5 taken alone line C-C.

FIG. 8 is a perspective, exploded view illustrating various components of the loudspeaker illustrated in FIG. 1, according to the example of the implementation illustrated in FIG. 3.

FIG. 9 is a cross-sectional view of an example of an electromagnetic driver or motor according to another implementation.

FIG. 10 is a top plan view of a stacked arrangement of components of a magnetic assembly according to another example of an implementation of the invention.

FIG. 11 is a side cross-sectional view of the stacked arrangement illustrated in FIG. 10 taken along line D-D.

Claims

1. An electromagnetic driver for use in an electromagnetic transducer, the electromagnetic driver comprising: a magnetic assembly having at least two magnets and a spacer positioned between the at least two magnets; anda coil former having a first coil portion and a second coil portion.

2. The driver of claim 1 where the magnetic assembly includes both an inner portion and an outer portion and where the inner portion of the magnetic assembly includes the at least two magnets and a spacer positioned between the at least two magnets.

3. The driver of claim 1 where the magnetic assembly includes both an inner portion and an outer portion and where the outer portion of the magnetic assembly includes the at least two magnets and a spacer positioned between the at least two magnets.

4. The driver of claim 1 where each of the at least two magnets comprises more than one magnetic component.

5. The driver of claim 1 where the spacer comprises more than one component.

6. The driver of claim 1 where the spacer comprises ferromagnetic material.

7. An electromagnetic driver for use in an electromagnetic transducer, the electromagnetic driver comprising: an inner magnetic portion held in fixed relationship to an outer magnetic portion so as to form an air gap between the inner magnetic portion and the outer magnetic portion, the inner magnetic portion including:a first spacer member;a first permanent magnet;a second permanent magnet;a first pole piece capable of carrying magnetic flux; anda second pole piece capable of carrying magnetic flux, the first spacer member located between the first permanent magnet and the second permanent magnet, the first permanent magnet, the first spacer member, and the second permanent magnet located between the first pole piece and the second pole piece; anda coil former, a portion of the coil former located within the air gap and capable of a range of movement within the air gap along a first axis, the coil former having a first coil portion and a second coil portion, the coil former with the first coil portion and the second coil portion being adapted to oscillate in response to changes in electric current applied to the first coil portion and the second coil portion while subjected to a magnetic field in the air gap.

8. The electromagnetic driver of claim 7 where the inner magnetic portion includes a stack of components including the first permanent magnet, the first spacer member, the second permanent magnet and the second pole piece, the stack of components being arranged so that an alignment rod may be passed through an inner magnetic portion bore that includes a set of substantially aligned bores in the components in the stack of components.

9. The electromagnetic driver of claim 7 where the first spacer member is of a cylindrical shape.

10. The electromagnetic driver of claim 9 where the first spacer member has at least one bore for use with an alignment rod.

11. The electromagnetic driver of claim 7 where the first spacer member is a toroid.

12. The electromagnetic driver of claim 7 where the thickness of the first spacer member as measured along the first axis is more than the thickness of the first permanent magnet.

13. The electromagnetic driver of claim 7 where the thickness of the first spacer member as measured along the first axis is more than the combined thickness of the first permanent magnet and the second permanent magnet such that an aggregate thickness of the first permanent magnet and the first spacer member, and the second permanent magnet is more than double a thickness of an equivalent single magnet having a set of properties equivalent to a combination of the first permanent magnet and the second permanent magnet.

14. An electromagnetic driver for use in an electromagnetic transducer, the electromagnetic driver comprising: an inner magnetic portion held in fixed relationship to an outer magnetic portion so as to form an air gap between the inner magnetic portion and the outer magnetic portion, the outer magnetic portion including:a first spacer member;a first permanent magnet;a second permanent magnet;a first pole piece capable of carrying magnetic flux; anda second pole piece capable of carrying magnetic flux, the first spacer member located between the first permanent magnet and the second permanent magnet, the first permanent magnet, the first spacer member, and the second permanent magnet located between the first pole piece and the second pole piece; anda coil former, a portion of the coil former located within the air gap and capable of a range of movement within the air gap along a first axis, the coil former having a first coil portion and a second coil portion, the coil former with the first coil portion and the second coil portion being adapted to oscillate in response to changes in electric current applied to the first coil portion and the second coil portion while subject to a magnetic field in the air gap.

15. The electromagnetic driver of claim 14 where the first spacer member is a toroid.

16. The electromagnetic driver of claim 14 where the thickness of the first spacer member as measured along the first axis is more than the thickness of the first permanent magnet.

17. The electromagnetic driver of claim 14 where the thickness of the first spacer member as measured along the first axis is more than the combined thickness of the first permanent magnet and the second permanent magnet such that an aggregate thickness of the first permanent magnet and the first spacer member, and the second permanent magnet is more than double a thickness of an equivalent single magnet having a set of properties equivalent to a combination of the first permanent magnet and the second permanent magnet.

18. A loudspeaker driver structure for driving a vibratable diaphragm to produce sound comprising: a first magnetic gap between an inner magnetic portion aligned along a central axis and an outer magnetic portion aligned along the central axis, the first magnetic gap in proximity to a first pole piece on the inner magnetic portion;a second magnetic gap between the inner magnetic portion and the outer magnetic portion, the second magnetic gap in proximity to a second pole piece on the inner magnetic portion;the first pole piece separated from the second pole piece in the inner magnetic portion by a component stack including a first permanent magnet, a second permanent magnet, and a spacer member located between the first permanent magnet and the second permanent magnet; anda first coil portion and a second coil portion located spaced apart on a coil former as part of a voice coil assembly that is disposed about the central axis, drivingly coupled to the diaphragm and adapted for oscillation in a direction parallel to the central axis in response to electric current applied to the first coil portion and the second coil portion while subjected to a magnetic field.

19. The loudspeaker driver structure of claim 18 where the inner magnetic portion is a stack of components including the first permanent magnet, the spacer member, the second permanent magnet and the second pole piece, the stack of components being arranged so that an alignment rod may be passed through an inner magnetic portion bore that includes a set of substantially aligned bores in the components in the stack of components.

20. The loudspeaker driver of claim 18 where the spacer member is of a cylindrical shape.

21. The loudspeaker driver of claim 18 where the spacer member has at least one bore for use with an alignment rod.

22. The loudspeaker driver of claim 18 where the spacer member is a toroid.

23. The loudspeaker driver of claim 18 where the thickness of the spacer member as measured along the central axis is more than the thickness of the first permanent magnet.

24. The loudspeaker driver of claim 18 where the thickness of the spacer member as measured along the central axis is more than the combined thickness of the first permanent magnet and the second permanent magnet such that an aggregate thickness of the first permanent magnet and the spacer member, and the second permanent magnet is more than double a thickness of an equivalent single magnet having a set of properties equivalent to a combination of the first permanent magnet and the second permanent magnet.

25. A loudspeaker driver structure for driving a vibratable diaphragm to produce sound comprising: a first magnetic gap between an inner magnetic portion aligned along a central axis and an outer magnetic portion aligned along the central axis, the first magnetic gap in proximity to a first pole piece on the inner magnetic portion;a second magnetic gap between the inner magnetic portion and the outer magnetic portion, the second magnetic gap in proximity to a second pole piece on the inner magnetic portion;the first pole piece separated from the second pole piece in the outer magnetic portion by a component stack including a first permanent magnet, a second permanent magnet, and a spacer member located between the first permanent magnet and the second permanent magnet; anda first coil portion and a second coil portion located spaced apart on a coil former as part of a voice coil assembly that is disposed about the central axis, drivingly coupled to the diaphragm and adapted for oscillation in a direction parallel to the central axis in response to electric current applied to the first coil portion and the second coil portion while subjected to a magnetic field.

26. The loudspeaker driver of claim 25 where the spacer member is a toroid.

27. The loudspeaker driver of claim 25 where the thickness of the spacer member as measured along the central axis is more than the thickness of the first permanent magnet.

28. The loudspeaker driver of claim 25 where the thickness of the spacer member as measured along the central axis is more than the combined thickness of the first permanent magnet and the second permanent magnet such that an aggregate thickness of the first permanent magnet and the spacer member, and the second permanent magnet is more than double a thickness of an equivalent single magnet having a set of properties equivalent to a combination of the first permanent magnet and the second permanent magnet.