Magnet system for loudspeakers

• US 20020094107A1
• Filed: 05/02/2001
• Published: 07/18/2002
• Est. Priority Date: 01/16/2001
• Status: Active Grant

• Current Assignee: KEF Celestion Corporation (Gold Peak Industries Limited)
• Original Assignee: KH Technology, LLC
• Inventors: Cork, Paul
• Granted Patent: US 6,563,932 B2
• Time in Patent Office: Days
• US Class Current: 381/412
• CPC Class Codes: H04R 9/025 Magnetic circuit
• CPC Class Codes: H04R 9/06 Loudspeakers

Abstract

A loudspeaker having a compact magnet system that produces an increased magnetic flux. A seat has an outer wall that retains an magnet therein such that a channel is defined therebetween. A plate is positioned on top of the first magnet such that an air gap is created between the plate and the wall. A second magnet is positioned over the plate and an aperture is created axially through the second magnet, the plate, and the first magnet. A yoke having a planar region and a protruding region extending therefrom is position over the second magnet such that the protruding region extends through the aperture and connects with the seat. A voice coil is connected to a diaphragm and is moveably suspended within the gap. Application of an electric current to the voice coils causes movement of the diaphragm due to the magnetic flux created within the gap and thereby produces sound waves.

Claims

1. A magnetic assembly for use in transducers, comprising:

a seat having a top surface and a bottom surface;

an outer wall extending from said top surface in a substantially perpendicular direction thereto;

a first magnet having a first aperture axially defined therein being positioned upon said top surface of said seat such that a channel is defined between an outer periphery of said first magnet and said outer wall;

a plate having a second aperture axially defined therein being positioned upon said first magnet such that said first aperture and said second aperture are aligned;

a gap being defined between said plate and said outer wall;

a second magnet having a third aperture axially defined therein being positioned upon said plate such that said third aperture, said second aperture, and said first aperture are substantially aligned;

a yoke being positioned upon said second magnet and having a protruding member extending through said first aperture, said second aperture, and said third aperture and connecting to said seat.

2. The assembly of claim 1, wherein said first and second magnets and said plate are annular.

3. The assembly of claim 1, wherein said first and second magnets are constructed of neodymium iron boron.

4. The assembly of claim 1, wherein said first magnet and said second magnet are arranged such that similar polarities of each magnet are in proximal relation to one another.

5. The assembly of claim 1, wherein a first magnetic flux within said gap is produced and maintained by said first magnet, said plate, said wall, and said seat.

6. The assembly of claim 1, wherein a second magnetic flux within said gap is produced and maintained by said second magnet, said plate, said wall, said seat, and said yoke.

7. The assembly of claim 1, wherein a lip extends inwardly from an upper portion of said wall and is of substantially equal height as said plate such that said gap is narrower than said channel.

8. The assembly of claim 7, wherein a first magnetic flux within said gap is produced and maintained by said first magnet, said plate, said lip, said wall, and said seat.

9. The assembly of claim 7, wherein a second magnetic flux within said gap is produced and maintained by said second magnet, said plate, said lip, said wall, said seat, and said yoke.

10. The assembly of claim 1, wherein a void is defined substantially axially through said seat and is adapted to receive said protruding region of said yoke therein in an intimate relation.

11. The assembly of claim 10, wherein a structural adhesive securely attaches said protruding region to said seat.

12. The assembly of claim 1, wherein said seat, said plate, and said yoke are constructed of a material selected from a group consisting of low carbon steel, steel, pure iron, sintered iron, and cobalt steel.

13. The assembly of claim 1, wherein a heat resistant adhesive connects said seat, said first magnet, said plate, said second magnet and said yoke respectively.

14. The assembly of claim 1, wherein said wall has a lower portion that extends beyond said seat such that a groove is formed between said wall and said seat.

16. The assembly of claim 15, wherein a first magnetic flux within said gap is produced and maintained by said first magnet, said plate, said lip, said wall, and said seat.

17. The assembly of claim 15, wherein a second magnetic flux within said gap is produced and maintained by said second magnet, said plate, said lip, said wall, said seat, said protruding region, and said planar region of said yoke.

18. The assembly of claim 15, wherein a first magnetic flux within said gap is produced and maintained by said first magnet, said plate, said lip, said wall, and said seat;

and

a second magnetic flux within said gap is produced and maintained by said second magnet, said plate, said lip, said wall, said seat, said protruding region, and said planar region of said yoke.

19. The assembly of claim 15, wherein similar polarities of said first magnet and said second magnet are positioned in proximal relations.

15. A magnetic assembly for a transducer producing an increased magnetic flux, comprising:

a seat having a top surface and a bottom surface and axially defining a void therein;

an annular outer wall extending from said seat in a substantially perpendicular direction thereto;

an annular lip extending inwardly from said wall at a point distal to said seat;

an annular first magnet having a first aperture axially defined therein being positioned upon said top surface of said seat such that a channel is defined between an outer periphery of said first magnet and said outer wall;

an annular plate having a second aperture axially defined therein being positioned upon said first magnet such that said first aperture and said second aperture are aligned;

a gap being defined between said plate and said annular lip;

an annular second magnet having a third aperture axially defined therein being positioned upon said plate such that said third aperture, said second aperture, and said first aperture are substantially aligned;

a yoke being positioned upon said second magnet and having a planar region and a protruding region extending therefrom in a substantially perpendicular manner such that said protruding region passes through said first aperture, said second aperture, and said third aperture and is intimately maintained within said void defined by said seat.

20. A loudspeaker assembly having decreased distortion and an increased magnetic flux, comprising:

a seat having a top surface and a bottom surface and axially defining a void therein;

an annular outer wall extending from said seat in a substantially perpendicular direction thereto;

an annular lip extending inwardly from said wall at a point distal to said seat;

an annular first magnet having a first aperture axially defined therein being positioned upon said top surface of said seat such that a channel is defined between an outer periphery of said first magnet and said outer wall;

an annular plate having a second aperture axially defined therein being positioned upon said first magnet such that said first aperture and said second aperture are aligned;

a gap being defined between said plate and said annular lip;

an annular second magnet having a third aperture axially defined therein being positioned upon said plate such that said third aperture, said second aperture, and said first aperture are substantially aligned;

a yoke being positioned upon said second magnet and having a planar region and a protruding region extending therefrom in a substantially perpendicular manner such that said protruding region passes through said first aperture, said second aperture, and said third aperture and is intimately maintained within said void defined by said seat;

a bobbin having a voice coil maintained thereon being moveably suspended within said gap;

a diaphragm connected to said bobbin distal to said voice coil;

a chassis connecting to said wall and flexibly attaching to said diaphragm distal to said bobbin; and

a suspension member attaching said bobbin to said chassis such that it is moveably suspended within said gap.