Permanent magnet system with associated coil arrangement

• US 5,214,710 A
• Filed: 07/05/1991
• Issued: 05/25/1993
• Est. Priority Date: 07/07/1990
• Status: Expired due to Fees

• Current Assignee: DaimlerChrysler AG (Mercedes-Benz Group AG)
• Original Assignee: Mercedes-Benz AG (Mercedes-Benz Group AG)
• Inventors: Ziegenberg, Alfred, Schiessle, Edmund
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Le, Huyen D.
• Application Number:
  US07/729,409
• Time in Patent Office: 690 Days
• Field of Search: 381/192, 381/194, 381/199, 381/200, 381/201, 381/195, 381/196, 381/197
• US Class Current: 381/412
• CPC Class Codes: H02K 33/18 with coil systems moving upon intermittent or reversed energisation thereof by interaction with a fixed field system, e.g. permanent magnets
• CPC Class Codes: H02K 35/04 with moving coil systems and stationary magnets
• CPC Class Codes: H04R 1/24 Structural combinations of separate transducers or of two parts of the same transducer and responsive respectively to two or more frequency ranges
• CPC Class Codes: H04R 2209/022 Aspects regarding the stray flux internal or external to the magnetic circuit, e.g. shielding, shape of magnetic circuit, flux compensation coils
• CPC Class Codes: H04R 9/025 Magnetic circuit
• CPC Class Codes: H04R 9/063 using a plurality of acoustic drivers H04R1/24 and H04R1/403 take precedence

Abstract

The invention relates to a permanent magnet system with associated coil arrangement, the permanent magnet system consisting of two axially polarized permanent magnet rings which are mounted one behind another in the axial direction, like poles of the permanent magnet rings being opposite one another, the two permanent magnet rings being distanced from one another by a soft magnetic spacing washer, the permanent magnet rings being surrounded on the outside by a coil in such a way that the coil central axis coincides with the central axis of the permanent magnet rings, the center of the coil being located in the normal position of the coil at the level of the soft magnetic spacing washer, at least one coil being located inside the inside diameter of the permanent magnet ring in such a way that the coil central axis of the coils coincides with the central axis of the permanent magnet rings, the center of the coils being located in the normal position of the coils at the level of the soft magnetic spacing washer. There are possible uses in loudspeakers and sensors.

Claims

1. Permanent magnet system with associated coil arrangement, comprising:

two axially polarized permanent magnet rings which are mounted one behind another in the axial direction with like poles of the permanent magnet rings being opposite one another;

a first soft magnetic spacing washer arranged between the two permanent magnet rings;

a first coil that surrounds the outside of the permanent magnet rings such that a central axis of the first coil coincides with a central axis of the permanent magnet rings, an axial center of the first coil being located in a normal position of the first coil at a level of the soft magnetic spacing washer;

wherein at least a second coil is located inside an inside diameter of the permanent magnet rings such that the central axis of the second coil coincides with the central axis of the permanent magnet rings, the center of the second coil being located in a normal position of the second coil at the level of the soft magnetic spacing washer.

2. The system of claim 1, further comprising an axial extension having a third axially polarized permanent magnet ring and a second soft magnetic spacing washer, axially arranged in relation to the two axially polarized permanent magnet rings and in relation to the second soft magnetic spacing washer such that like poles of the third axially polarized permanent magnet ring and of the first permanent magnet ring being opposite one another, the first permanent magnet ring being adjacent to the third permanent magnet ring, and the third permanent magnet ring being separated from the first permanent magnet ring by the second soft magnetic spacing washer;

at least a third coil that surrounds the first, second and third permanent magnet rings on the outside of said permanent magnet rings such that a central axis of the third coil coincides with the central axis of the permanent magnet rings, the center of the third coil being located in a normal position of the third coil at the level of the second soft magnetic spacing washer; and

at least a fourth coil arranged inside the inside diameter of the permanent magnet rings such that a central axis of the fourth coil coincides with the central axis of the permanent magnet rings, the center of the fourth coil being located in a normal position of the fourth coil at the level of the second soft magnetic spacing washer.

3. The system of claim 2, wherein the soft magnetic spacing washers have a smaller inside diameter and a larger outside diameter than the permanent magnet rings that are separated by the respective soft magnetic spacing washers.

4. The system of claim 2, further comprising a radial extension having at least a fourth axially polarized permanent magnet ring and at least a third soft magnetic spacing washer a central axis of the fourth permanent magnet ring and of the third soft magnetic spacing washer coinciding with the central axes of the first, second and third permanent magnet rings, an inside diameter of the fourth permanent magnet ring being larger than an outside diameter of the first, second and third permanent magnet rings and of the first and second soft magnetic spacing washers such that at least a fifth coil is insertable between the fourth permanent magnet ring and the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers, an inside diameter of the third soft magnetic spacing washer being larger than the outside diameters of the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers such that at least a sixth coil is insertable between the third soft magnetic spacing washer and the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers, with like poles of the fourth permanent magnet ring and of an adjacent first, second or third permanent magnet ring being directly adjacent to one another, and wherein the fourth permanent magnet ring is surrounded on the outside by at least a seventh coil such that a central axis of the seventh coil coincides with the central axis of the fourth permanent magnet ring, the center of the seventh coil being located in a normal position of the seventh coil at the level of the third soft magnetic spacing washer, and at least an eighth coil is located inside an inside diameter of the fourth permanent magnet ring such that the central axis of the eighth coil coincides with the central axis of the fourth permanent magnet ring, the center of the eighth coil being located in a normal position of the eighth coil at the level of the third soft magnetic spacing washer, and a layer of an amorphous, very soft magnetic and non-magnetostrictive material located between the eighth coil and the third coil surrounding the permanent magnet rings on the outside.

5. The system of claim 4, wherein the soft magnetic spacing washers have a smaller inside diameter and a larger outside diameter than the permanent magnet rings that are separated by the respective soft magnetic spacing washers.

6. The system of claim 1, wherein a layer of an amorphous, very soft magnetic and non-magnetostrictive material is located at least on one of the inner lateral surface of the internal coils and on the outer lateral surface of the external coils.

7. The system of claim 6, wherein the layer is a metal foil forming a thin-walled ring.

8. The system of claim 7, wherein the layer is provided at its ends points with an extension in the direction of the poles of the corresponding permanent magnet ring.

9. The system of claim 1, wherein the soft magnetic spacing washers have a smaller inside diameter and a larger outside diameter than the permanent magnet rings that are separated by the respective soft magnetic spacing washers.

10. The system of claim 1, wherein at least one of the coils is a plurality of at least two interlocking coils.

11. The system of claim 1, further comprising a radial extension having at least a third axially polarized permanent magnet ring and at least a second soft magnetic spacing washer, a central axis of the third permanent magnet ring and of the second soft magnetic spacing washer coinciding with the central axes of the first and second permanent magnet rings, an inside diameter of the third permanent magnet ring being larger than an outside diameter of the first and second permanent magnet rings and of the first soft magnetic spacing washer such that at least a third coil is insertable between the third permanent magnet ring and the first and second permanent magnet rings and the first soft magnetic spacing washer, an inside diameter of the second soft magnetic spacing washer being larger than the outside diameters of the first and second permanent magnet rings and the first and second soft magnetic spacing washers such that at least a fourth coil is insertable between the second soft magnetic spacing washer and the first and second permanent magnet rings and the first and second soft magnetic spacing washers, with like poles of the third permanent magnet ring and of an adjacent first or second permanent magnet ring being directly adjacent to one another, and wherein the third permanent magnet ring is surrounded on the outside by at least a fifth coil such that a central axis of the fifth coil coincides with the central axis of the third permanent magnet ring, the center of the fifth coil being located in a normal position of the fifth coil at the level of the second soft magnetic spacing washer, and at least a sixth coil is located inside an inside diameter of the third permanent magnet ring such that the central axis of the sixth coil coincides with the central axis of the third permanent magnet ring, the center of the sixth coil being located in a normal position of the sixth coil at the level of the second soft magnetic spacing washer, and a layer of an amorphous, very soft magnetic and non-magnetostrictive material located between the sixth coil and the third coil surrounding the permanent magnet rings on the outside.

12. An analog-controlled loudspeaker comprising;

a diaphragm; and

a permanent magnet system with associated coil arrangement, that includes;

two axially polarized permanent magnet rings which are mounted one behind another in the axial direction with like poles of the permanent magnet rings being opposite one another;

a first soft magnetic spacing washer arranged between the two permanent magnet rings;

a first coil that surrounds the outside of the permanent magnet rings such that a central axis of the first coil coincides with a central axis of the permanent magnet rings, an axial center of the first coil being located in a normal position of the first coil at a level of the soft magnetic spacing washer;

wherein at least a second coil is located inside an inside diameter of the permanent magnet rings such that the central axis of the second coil coincides with the central axis of the permanent magnet rings, the center of the second coil being located in a normal position of the second coil at the level of the soft magnetic spacing washer.

13. Loudspeaker according to claim 12, wherein the diaphragm of the loudspeaker consists of one piece and is firmly connected to the coil arrangement in such a way that the coil arrangement drives the loudspeaker diaphragm as a vibrating-coil arrangement.

14. Loudspeaker according to claim 13, wherein the coils of the coil arrangement are firmly connected to one another by a connecting plate, and in that a firm connection of the diaphragm exists with the connecting plate.

15. Loudspeaker according to claim 12, wherein the coil arrangement is subdivided into radially internal coils and radially external coils, and in that the diaphragm is subdivided corresponding to the subdivision of the coil arrangement into a plurality of parts, of which each part of the diaphragm is connected to a part of the coils of the coil arrangement.

16. The loudspeaker of claim 12, further comprising an axial extension having a third axially polarized permanent magnet ring and a second soft magnetic spacing washer, axially arranged in relation to the two axially polarized permanent magnet rings and in relation to the second soft magnetic spacing washer such that like poles of the third axially polarized permanent magnet ring and of the first permanent magnet ring being opposite one another, the first permanent magnet ring being adjacent to the third permanent magnet ring, and the third permanent magnet ring being separated from the first permanent magnet ring by the second soft magnetic spacing washer;

at least a third coil that surrounds the first, second and third permanent magnet rings on the outside of said permanent magnet rings such that a central axis of the third coil coincides with the central axis of the permanent magnet rings, the center of the third coil being located in a normal position of the third coil at the level of the second soft magnetic spacing washer; and

at least a fourth coil arranged inside the inside diameter of the permanent magnet rings such that a central axis of the fourth coil coincides with the central axis of the permanent magnet rings, the center of the fourth coil being located in a normal position of the fourth coil at the level of the second soft magnetic spacing washer.

17. The loudspeaker of claim 16, further comprising a radial extension having at least a fourth axially polarized permanent magnet ring and at least a third soft magnetic spacing washer, a central axis of the fourth permanent magnet ring and of the third soft magnetic spacing washer coinciding with the central axes of the first, second and third permanent magnet rings, an inside diameter of the fourth permanent magnet ring being larger than an outside diameter of the first, second and third permanent magnet rings and of the first and second soft magnetic spacing washers such that at least a fifth coil is insertable between the fourth permanent magnet ring and the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers, an inside diameter of the third soft magnetic spacing washer being larger than the outside diameters of the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers such that at least a sixth coil is insertable between the third soft magnetic spacing washer and the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers, with like poles of the fourth permanent magnet ring and of an adjacent first, second or third permanent magnet ring being directly adjacent to one another, and wherein the fourth permanent magnet ring is surrounded on the outside by at least a seventh coil such that a central axis of the seventh coil coincides with the central axis of the fourth permanent magnet ring, the center of the seventh coil being located in a normal position of the seventh coil at the level of the third soft magnetic spacing washer, and at least an eighth coil is located inside an inside diameter of the fourth permanent magnet ring such that the central axis of the eighth coil coincides with the central axis of the fourth permanent magnet ring, the center of the eighth coil being located in a normal position of the eighth coil at the level of the third soft magnetic spacing washer, and a layer of an amorphous, very soft magnetic and non-magnetostrictive material located between the eighth coil and the third coil surrounding the permanent magnet rings on the outside.

18. A digitally-controlled loudspeaker, comprising:

a diaphragm;

a permanent magnet system with associated coil arrangement, including;

two axially polarized permanent magnet rings which are mounted one behind another in the axial direction with like poles of the permanent magnet rings being opposite one another;

a first soft magnetic spacing washer arranged between the two permanent magnet rings;

a first coil that surrounds the outside of the permanent magnet rings such that a central axis of the first coil coincides with a central axis of the permanent magnet rings, an axial center of the first coil being located in a normal position of the first coil at a level of the soft magnetic spacing washer;

wherein at least a second coil is located inside an inside diameter of the permanent magnet rings such that the central axis of the second coil coincides with the central axis of the permanent magnet rings, the center of the second coil being located in a normal position of the second coil at the level of the soft magnetic spacing washer;

wherein the coil arrangement is subdivided such that each control signal to a coil corresponds to one bit.

19. The loudspeaker of claim 18, further comprising an axial extension having a third axially polarized permanent magnet ring and a second soft magnetic spacing washer, axially arranged in relation to the two axially polarized permanent magnet rings and in relation to the second soft magnetic spacing washer such that like poles of the third axially polarized permanent magnet ring and of the first permanent magnet ring being opposite one another, the first permanent magnet ring being adjacent to the third permanent magnet ring, and the third permanent magnet ring being separated from the first permanent magnet ring by the second soft magnetic spacing washer;

at least a third coil that surrounds the first, second and third permanent magnet rings on the outside of said permanent magnet rings such that a central axis of the third coil coincides with the central axis of the permanent magnet rings, the center of the third coil being located in a normal position of the third coil at the level of the second soft magnetic spacing washer; and

at least a fourth coil arranged inside the inside diameter of the permanent magnet rings such that a central axis of the fourth coil coincides with the central axis of the permanent magnet rings, the center of the fourth coil being located in a normal position of the fourth coil at the level of the second soft magnetic spacing washer.

20. The loudspeaker of claim 19, further comprising a radial extension having at least a fourth axially polarized permanent magnet ring and at least a third soft magnetic spacing washer, a central axis of the fourth permanent magnet ring and of the third soft magnetic spacing washer coinciding with the central axes of the first, second and third permanent magnet rings, an inside diameter of the fourth permanent magnet ring being larger than an outside diameter of the first, second and third permanent magnet rings and of the first and second soft magnetic spacing washers such that at least a fifth coil is insertable between the fourth permanent magnet ring and the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers, an inside diameter of the third soft magnetic spacing washer being larger than the outside diameters of the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers such that at least a sixth coil is insertable between the third soft magnetic spacing washer and the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers, with like poles of the fourth permanent magnet ring and of an adjacent first, second or third permanent magnet ring being directly adjacent to one another, and wherein the fourth permanent magnet ring is surrounded on the outside by at least a seventh coil such that a central axis of the seventh coil coincides with the central axis of the fourth permanent magnet ring, the center of the seventh coil being located in a normal position of the seventh coil at the level of the third soft magnetic spacing washer(s), and at least an eighth coil is located inside an inside diameter of the fourth permanent magnet ring such that the central axis of the eighth coil coincides with the central axis of the fourth permanent magnet ring, the center of the eighth coil being located in a normal position of the eighth coil at the level of the third soft magnetic spacing washer, and a layer of an amorphous, very soft magnetic and non-magnetostrictive material located between the eighth coil and the third coil surrounding the permanent magnet rings on the outside.

21. A sensor for determining a motion-dependent variable, comprising:

a permanent magnet system with associated coil arrangement, including;

two axially polarized permanent magnet rings which are mounted one behind another in the axial direction with like poles of the permanent magnet rings being opposite one another;

a first soft magnetic spacing washer arranged between the two permanent magnet rings;

a first coil that surrounds the outside of the permanent magnet rings such that a central axis of the first coil coincides with a central axis of the permanent magnet rings, an axial center of the first coil being located in a normal position of the first coil at a level of the soft magnetic spacing washer;

wherein at least a second coil is located inside an inside diameter of the permanent magnet rings such that the central axis of the second coil coincides with the central axis of the permanent magnet rings, the center of the second coil being located in a normal position of the second coil at the level of the soft magnetic spacing washer;

wherein a movement of the coil arrangement with respect to the permanent magnet system induces a voltage in the coils of the coil arrangement.

22. Sensor according to claim 21, wherein the coil arrangement is firmly connectable to a body exerting a vibration, the permanent magnet system being arranged in a fixed position.

23. Sensor according to claim 21, wherein the permanent magnet system is firmly connected by the base of a housing to a sensing object which executes a movement, and the coil arrangement is supported on the base of a housing by a spring in such a way that given a deflection of the coil arrangement from its rest position a restoring force proportional to this deflection is produced.

24. Sensor according to claim 21, wherein the coil arrangement is directly subjected to a pressure which leads to a deflection of the coil arrangement relative to the permanent magnet system which is proportional to the pressure, the permanent magnet system being arranged in a fixed position.

25. The sensor of claim 21, further comprising an axial extension having a third axially polarized permanent magnet ring and a second soft magnetic spacing washer, axially arranged in relation to the two axially polarized permanent magnet rings and in relation to the second soft magnetic spacing washer such that like poles of the third axially polarized permanent magnet ring and of the first permanent magnet ring being opposite one another, the first permanent magnet ring being adjacent to the third permanent magnet ring, and the third permanent magnet ring being separated from the first permanent magnet ring by the second soft magnetic spacing washer;

at least a third coil that surrounds the first, second and third permanent magnet rings on the outside of said permanent magnet rings such that a central axis of the third coil coincides with the central axis of the permanent magnet rings, the center of the third coil being located in a normal position of the third coil at the level of the second soft magnetic spacing washer; and

at least a fourth coil arranged inside the inside diameter of the permanent magnet rings such that a central axis of the fourth coil coincides with the central axis of the permanent magnet rings, the center of the fourth coil being located in a normal position of the fourth coil at the level of the second soft magnetic spacing washer.

26. The sensor of claim 25, further comprising a radial extension having at least a fourth axially polarized permanent magnet ring and at least a third soft magnetic spacing washer a central axis of the fourth permanent magnet ring and of the third soft magnetic spacing washer coinciding with the central axes of the first, second and third permanent magnet rings, an inside diameter of the fourth permanent magnet ring being larger than an outside diameter of the first, second and third permanent magnet rings and of the first and second soft magnetic spacing washers such that at least a fifth coil is insertable between the fourth permanent magnet ring and the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers, an inside diameter of the third soft magnetic spacing washer being larger than the outside diameters of the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers such that at least a sixth coil is insertable between the third soft magnetic spacing washer and the first, second and third permanent magnet rings and the first and second soft magnetic spacing washers, with like poles of the fourth permanent magnet ring and of an adjacent first, second or third permanent magnet ring being directly adjacent to one another, and wherein the fourth permanent magnet ring is surrounded on the outside by at least a seventh coil such that a central axis of the seventh coil coincides with the central axis of the fourth permanent magnet ring, the center of the seventh coil being located in a normal position of the seventh coil at the level of the third soft magnetic spacing washer(s), and at least an eighth coil is located inside an inside diameter of the fourth permanent magnet ring such that the central axis of the eighth coil coincides with the central axis of the fourth permanent magnet ring, the center of the eighth coil being located in a normal position of the eighth coil at the level of the third soft magnetic spacing washer, and a layer of an amorphous, very soft magnetic and non-magnetostrictive material located between the eighth coil and the third coil surrounding the permanent magnet rings on the outside.