Choke coil

• US 6,774,755 B2
• Filed: 12/10/1998
• Issued: 08/10/2004
• Est. Priority Date: 10/24/1996
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Takagi, Kiyoshi, Omura, Katsunori, Nakata, Toshiyuki, Nakashima, Koji
• Primary Examiner(s): Nguyen, Tuyen T.
• Application Number:
  US09/091,805
• Publication Number:
  US 20020067237A1
• Time in Patent Office: 2,070 Days
• Field of Search: 336/83, 336/192, 336/198, 336/200, 336/223, 336/232, 336/212
• US Class Current: 336/83
• CPC Class Codes: H01F 27/29 Terminals; Tapping arrangements for signal inductances
• CPC Class Codes: H01F 27/292 Surface mounted devices
• CPC Class Codes: H01F 37/00 Fixed inductances not covered by group H01F17/00

Abstract

The present invention relates to a choke coil utilized in a variety of electronic products both for industrial use and consumer use, and aims to provide a choke coil that is thinner in size, accommodates a larger current, provides better efficiency in assembly and higher reliability. The choke coil of the present invention comprises a closing magnetic core having a center magnetic leg, an outer magnetic leg 36 and a common magnetic yoke. A coreless coil winds a plate-type wire around the center magnetic leg of the closing magnetic core to form itself, and is mounted to the closing magnetic core. At least one terminal coupled to an inner turn of the coreless coil out of terminals coupled to both ends of the plate-type wire of the coreless coil is led out from a notch provided on one side of the common magnetic yoke of the closing magnetic core.

Claims

1. A choke coil comprising:

a closing magnetic core including a first magnetic core comprising a center magnetic leg, an outer magnetic leg, and a first common magnetic yoke, and a second magnetic core comprising a second common magnetic yoke in contact with said first magnetic core;

a coreless coil including a plate-type wire comprising at least one of a flat type wire and a foil type wire, wherein said coreless coil is disposed around the center magnetic leg and separated therefrom by an insulating layer; and

inside and outside terminals respectively coupled to inside and outside ends of the plate-type wire of the coreless coil,

wherein one of said first common magnetic yoke and said second magnetic yoke has a substantially planar body portion having first and second sides with a predetermined thickness therebetween and a notch formed in the planar body portion, the notch extending between the first and second planar sides, and

wherein said inside terminal extends outside said closing magnetic core through said notch, said inside terminal having a portion that extends substantially parallel with said planar body portion inside the notch within the thickness of said planar body.

2. The choke coil as defined in claim 1, wherein the insulating layer comprises a terminal base.

3. The choke coil as defined in claim 2, wherein said terminal base comprises a base plate and a cylinder, located in a center of the terminal base, wherein said cylinder engages with the center magnetic leg.

4. The choke coil as defined in claim 2, wherein said terminal base comprises a cylinder, coupled to a separate base plate.

5. The choke coil as defined in claim 2, wherein said terminal base comprises a base plate having a support protrusion at each corner thereof.

6. The choke coil as defined in claim 5, wherein said terminal base further comprises a cylinder engaging with the center magnetic leg, and each of said support protrusions at each corner has a taper on a face opposing the cylinder.

7. The choke coil as defined in claim 2, wherein the coreless coil is incorporated into said terminal base as one molding.

8. The choke coil as defined in claim 1, wherein said first magnetic core and said second magnetic core of said closing magnetic core comprise at least one of an EE-shape, an EI-shape, and a TU-shape.

9. The choke coil as defined in claim 8, wherein said closing magnetic core comprises a manganese ferrite core.

10. The choke coil as defined in claim 1, wherein a magnetic gap is provided between said center magnetic leg of said first magnetic core and said second magnetic core.

11. The choke coil as defined in claim 1, wherein said center magnetic leg of said first magnetic core has a cross section shaped in at least one of a circle, an ellipse, and an oval.

12. The choke coil as defined in claim 1, wherein one of a cavity, a notch, and a hole is provided at a place corresponding to the inside terminal in the other of the first and second common magnetic yokes opposite the notch formed in one of the first and second common magnetic yokes.

13. The choke coil as defined in claim 1, wherein said coreless coil is shaped in at least one of a circle, an oval, and an ellipse responsive to a shape of said center magnetic leg.

14. The choke coil as defined in claim 1, further comprising an insulating sheet provided between the coreless coil and the closing magnetic core.

15. The choke coil as defined in claim 1, wherein the inner terminal and the outer terminal each comprise at least one of a plate-type terminal and a pin-type terminal.

16. The choke coil as defined in claim 1, wherein the insulating layer includes a positioning protrusion that fits into the at least one of the notches.

17. The choke coil as defined in claim 1, wherein the portion of the inside terminal that extends substantially parallel with the planar body portion, is substantially flush with one of the first and second sides thereof.

18. The choke coil as defined in claim 14, wherein said insulating sheet includes at least one of an opening which fits into the center magnetic leg of the closing magnetic core, and an engaging part at each outside corner thereof.

19. A choke coil comprising:

a closing magnetic core including a first magnetic core comprising a center magnetic leg, an outer magnetic leg, and a first common magnetic yoke, and a second magnetic core comprising a second common magnetic yoke in contact with said first magnetic core;

a coreless coil including a plate-type wire comprising at least one of a flat type wire and a foil type wire, wherein said coreless coil is disposed around the center magnetic leg and separated therefrom by an insulating layer; and

inside and outside terminals respectively coupled to inside and outside ends of the plate-type wire of the coreless coil,

wherein said inside terminal is led outside said closing magnetic core through at least one of a notch in the first common magnetic yoke and a notch in the second common magnetic yoke, and

wherein said inside terminal is led outside said closing magnetic core through at least one of;

a notch in the first common magnetic yoke;

a through hole in the first common magnetic yoke;

a notch in the second common magnetic yoke; and

a through hole in the second common magnetic yoke,

wherein said insulating layer comprises a terminal base,

wherein said terminal base comprises a base plate and a cylinder, located in a center of the terminal base, wherein said cylinder engages with the center magnetic leg, and

wherein a thickness of a wall of said cylinder of the terminal base varies from a minimum thickness to a maximum thickness, and wherein a guiding portion is provided at the point of maximum thickness of the wall of said cylinder and the guiding portion engages with the inner terminal of the coreless coil.

20. A choke coil comprising:

a closing magnetic core including a first magnetic core comprising a center magnetic leg, an outer magnetic leg, and a first common magnetic yoke, and a second magnetic core comprising a second common magnetic yoke in contact with said first magnetic core;

a coreless coil including a plate-type wire comprising at least one of a flat type wire and a foil type wire, wherein said coreless coil is disposed around the center magnetic leg and separated therefrom by an insulating layer; and

inside and outside terminals respectively coupled to inside and outside ends of the plate-type wire of the coreless coil,

wherein the inside terminal is led outside the closing magnetic core through at least one of a notch and a through hole provided in the first common magnetic yoke; and

wherein a thickness of the second common magnetic yoke is 65-90% of a thickness of the first common magnetic yoke.

21. A choke coil comprising:

a closing magnetic core including a first magnetic core comprising a center magnetic leg, an outer magnetic leg, and a first common magnetic yoke, and a second magnetic core comprising a second common magnetic yoke in contact with said first magnetic core;

a coreless coil including a plate-type wire comprising at least one of a flat type wire and a foil type wire, wherein said coreless coil is disposed around the center magnetic leg and separated therefrom by an insulating layer; and

inside and outside terminals respectively coupled to inside and outside ends of the plate-type wire of the coreless coil,

wherein the inside terminal is led outside the closing magnetic core through at least one of a notch and a through hole provided in the second common magnetic yoke; and

wherein a thickness of the first common magnetic yoke is 60-90% of a thickness of the second common magnetic yoke.