Wire core inductive devices having a biassing magnet and methods of making the same

• US 6,885,270 B2
• Filed: 01/23/2002
• Issued: 04/26/2005
• Est. Priority Date: 01/23/2001
• Status: Expired due to Fees

• Current Assignee: Harrie R. Buswell
• Original Assignee: Harrie R. Buswell
• Inventors: Buswell, Harrie R.
• Primary Examiner(s): MAI, ANH T
• Application Number:
  US10/470,004
• Publication Number:
  US 20040051617A1
• Time in Patent Office: 1,189 Days
• Field of Search: 336/83, 336/233, 336/60, 336/234, 336/229, 296/021, 296/06
• US Class Current: 336/83
• CPC Class Codes: H01F 17/06 with core substantially closed in itself, e.g. toroid
• CPC Class Codes: H01F 2003/103 Magnetic circuits with permanent magnets
• CPC Class Codes: H01F 27/34 Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/366 made of ferromagnetic material
• CPC Class Codes: H01F 3/06 made from wires
• CPC Class Codes: H01F 30/16 Toroidal transformers
• CPC Class Codes: H01F 41/02 for manufacturing cores, coils, or magnets H01F41/14 takes precedence; for dynamo-electric machines H02K15/00
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor

Abstract

An inductive device comprises a magnetic core including a portion of a plurality of wires, at least one electric winding extending around the magnetic core, each of the plurality of wires substantially encircling the at least one electric winding, and at least one biassing magnet disposed adjacent the plurality of wires to provide a bias magnet flux for offsetting a flux generated by a direct current component flowing in the winding.

Claims

1. An inductive device comprising:

a magnetic core including a portion of a plurality of wires;

at least one electric winding extending around said magnetic core, each of said plurality of wires at least partially encircling said at least one electric winding and completing a magnetic circuit; and

at least one biassing magnet disposed adjacent said plurality of wires and applying a magnetic bias to said magnetic circuit.

2. An inductive device as recited in claim 1, wherein said biasing is a permanent magnet.

3. An inductive device as recited in claim 1, wherein at least one of said plurality of wires substantially encircles said biassing magnet.

4. An inductive device as recited in claim 1, wherein said biassing magnet is disposed at an end of the inductive device.

5. An inductive device as recited in claim 1, wherein said biasing magnet is disposed at an end of said magnetic core.

6. An inductive device as recited in claim 5, wherein at least one of said plurality of wires substantially encircles said biassing magnet.

7. An inductive device as recited in claim 1, further comprising a second biassing magnet, wherein said one biassing magnet and said second biassing magnet are disposed at opposite ends of said magnetic core.

8. An inductive device as recited in claim 7, wherein at least one of said plurality of wires substantially encircles said biassing magnet and said second biassing magnet.

9. An inductive device as recited in claim 1, wherein said biassing magnet is a hollow cylinder substantially encircling said plurality of wires.

10. An inductive device as recited in claim 1, wherein said biassing magnet is disposed adjacent said magnetic core.

11. An inductive device as recited in claim 1, wherein said biassing magnet is a hollow cylinder substantially encircling a portion of said magnetic core.

12. An inductive device as recited in claim 1, wherein said biassing magnet is a hollow cylinder substantially encircling said magnetic core.

13. An inductive device as recited in claim 1, wherein said biassing magnet is disposed among said portion of said plurality of wires of said magnetic core.

14. An inductive device as recited in claim 10, wherein said biassing magnet is a cylindrical.

15. An inductive device as recited in claim 1, wherein said plurality of wires include wires of different cross-sections arranged to increase the density of said magnetic core.

16. An inductive device as recited in claim 1, wherein said plurality of wires substantially envelop said at least one electric winding to provide shielding from electromagnetic fields.

17. An inductive device as recited in claim 1, wherein each of said plurality of wires includes a first end and a second end that substantially abut one another.

18. An inductive device as recited in claim 17, wherein said first and second ends of each wire meet.

19. An inductive device as recited in claim 17, wherein said first and second ends of each wire are secured in place.

20. An inductive device as recited in claim 19, wherein said first and second ends of said plurality of wires are secured by a band.

21. An inductive device as recited in claim 1, wherein each of said plurality of wires includes a first end and a second end that oppose one another across a gap, and said biassing magnet is disposed adjacent said gap.

22. An inductive device as recited in claim 21, wherein said biassing magnet is received in said gap.

23. An inductive device as recited in claim 1, further comprising a mounting post disposed among said plurality of wires and extending from said plurality of wires.

24. An inductive device as recited in claim 23, wherein the mounting post extends from said plurality of wires only at one end of the inductive device.

25. An inductive device as recited in claim 1, further comprising a second electric winding extending around said magnetic core.

26. An inductive device as recited in claim 25, wherein said second electric winding is axially displaced from said at least one electric winding.

27. An inductive device as recited in claim 25, wherein said second electric winding is arranged concentrically with said at least one electric winding.

28. An inductive device as recited in claim 1, wherein said at least one electric winding is in direct contact with said magnetic core.

29. An inductive device as recited in claim 1, wherein said plurality of wires are electrically insulated from one another.

30. A method for making an inductive device, comprising:

providing a magnetic core including a portion of a plurality of wires,

arranging at least one electric winding around the magnetic core;

configuring each of the plurality of wires so as to at least partially encircle the at least one electric winding and complete a magnetic circuit; and

providing at least one biassing magnet adjacent the plurality of wires to apply a magnetic bias to said magnetic circuit.

31. A method as recited in claim 30, wherein at least one of said plurality of wires substantially encircles said biassing magnet.

32. A method as recited in claim 31, wherein said biassing magnet is disposed at an end of said magnetic core.

33. A method as recited in claim 30, wherein said biassing magnet is disposed at an end of said inductive device.

34. A method as recited in claim 30, further comprising providing a second biassing magnet, wherein said biassing magnet and said second biassing magnet are disposed at opposite ends of said magnetic core.

35. A method as recited in claim 34, wherein at least one of said plurality of wires substantially encircles said one biassing magnet and said second biassing magnet.

36. A method as recited in claim 30, wherein the plurality of wires include wires of different cross-sections arranged to increase the density of the magnetic core.

37. A method as recited in claim 30, wherein said configuring includes substantially abutting first and second ends of each of the plurality of wires.

38. A method as recited in claim 30, wherein said configuring includes securing first and second ends of each of the plurality of wires in place.

39. A method as recited in claim 38, wherein said securing includes wrapping a band around the plurality of wires.

40. A method as recited in claim 38, wherein said biassing magnet is a permanent magnet.