Magnetic element and method of manufacturing magnetic element

• US 7,449,984 B2
• Filed: 04/24/2006
• Issued: 11/11/2008
• Est. Priority Date: 12/10/2003
• Status: Active Grant

• Current Assignee: Sumida Corporation
• Original Assignee: Sumida Corporation
• Inventors: Kawarai, Mitsugu
• Primary Examiner(s): Enad; Elvin G
• Assistant Examiner(s): BAISA, JOSELITO SASIS
• Application Number:
  US11/379,934
• Publication Number:
  US 20060186979A1
• Time in Patent Office: 932 Days
• Field of Search: 336/200, 336/83
• US Class Current: 336/83
• CPC Class Codes: H01F 17/043 with two, usually identical or nearly identical parts enclosing completely the coil (pot cores)
• CPC Class Codes: H01F 17/045 with core of cylindric geometry and coil wound along its longitudinal axis, i.e. rod or drum core
• CPC Class Codes: H01F 2003/106 Magnetic circuits using combinations of different magnetic materials
• CPC Class Codes: H01F 2017/046 helical coil made of flat wire, e.g. with smaller extension of wire cross section in the direction of the longitudinal axis
• CPC Class Codes: H01F 2017/048 with encapsulating core, e.g. made of resin and magnetic powder
• CPC Class Codes: H01F 27/292 Surface mounted devices
• CPC Class Codes: H01F 27/327 Encapsulating or impregnating encapsulating coil and core H01F27/022
• CPC Class Codes: H01F 41/127 Encapsulating or impregnating encapsulating coil and core H01F41/005
• CPC Class Codes: Y10T 29/4902 Electromagnet, transformer or inductor
• CPC Class Codes: Y10T 29/49021 Magnetic recording reproducing transducer [e.g., tape head, core, etc.]
• CPC Class Codes: Y10T 29/4903 with bonding
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base
• CPC Class Codes: Y10T 29/49158 with molding of insulated base
• CPC Class Codes: Y10T 29/49172 by molding of insulating material

Abstract

There are provided a magnetic element capable of enhancing magnetic permeability of a magnetic member, improving a direct current superposition characteristic, and improving production efficiency and a method of manufacturing the magnetic element. The magnetic element includes a coil (30) formed of a conductor having an insulating film, a first core member (20) constituted of insulative soft magnetic ferrite and covering the coil (30), and a second core member (50) having soft magnetic metal powder as material and surrounded by the first core member (20). Furthermore, the magnetic element includes a third core member (40) which has soft magnetic metal powder as material and a higher filling ratio of the soft magnetic metal powder than the second core member 50 and is surrounded by the first core member (20).

Claims

1. A magnetic element, comprising:

a coil having end portions;

a first core member constituted of insulative soft magnetic ferrite;

said first core member having a bottom portion and side walls;

said side walls having recessed fitting portions that do not reach the bottom portion of said first core;

wherein the number of recessed fitting portions correspond to the number of end portions of said coil;

a second core member comprised of a magnetic metal powder and a resin;

said second core member being arranged into said first core member;

and a third core member having soft magnetic metal powder as material, having higher magnetic permeability than said second core member said third core member being arranged into said first core member; and

terminal electrodes being formed on outside of said first core member so as not to attach to said second core member and said third core member;

wherein said end portions of said coil extend out of said recessed fitting portions respectively to be connected to said terminal electrodes.

2. The magnetic element according to claim 1, wherein in magnetic flux generated from said coil, a part passing through said first core member, said second core member and said third core member one by one in serial order is larger than a part passing there through with at least one of said core members being excluded.

3. The magnetic element according to claim 1, wherein said third core member is formed in a column shape, an end surface of one end side of the column shape is mounted on a bottom portion of the cup body, and said third core member in the column shape is covered by said second core member.

4. The magnetic element according to claim 1, wherein said third core member is formed in a column shape, an end surface of one end side of the column shape is mounted on a bottom portion of the cup body, and said third core member in the column shape is formed to be level with an end surface of said second core member.

5. The magnetic element according to claim 1, wherein said third core member is formed in a lid body shape, and said third core member in the lid body shape is mounted on said second core member or said coil and blocks an opening portion of said cup body.

6. The magnetic element according to claim 1, wherein said third core member comprises a lid body portion in a lid body shape and a column portion in a column shape extending in a normal direction of said lid body portion from a center portion of said lid body portion, wherein with said lid body portion and said column portion, a cross section of said third core member forms a T shape, and wherein between said third core member and a bottom portion of said cup body, said second core member intervenes.

7. The magnetic element according to claim 1, wherein said coil is formed by patterning of metal on a heat resistant resin film.

8. The magnetic element according to claim 1, wherein between windings of said coil, said second core member does not exist.

9. The magnetic element according to claim 1, further comprising external electrodes electrically connected to said coil and attached to an outer peripheral surface of said first core member, wherein said external electrodes is formed of electrically conductive adhesive as material.