Magnetic element and method of manufacturing the same

• US 6,392,525 B1
• Filed: 12/27/1999
• Issued: 05/21/2002
• Est. Priority Date: 12/28/1998
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakatani, Seiichi, Hirano, Koichi, Asahi, Toshiyuki, Inoue, Osamu, Kato, Junichi
• Primary Examiner(s): Donovan, Lincoln
• Assistant Examiner(s): Nguyen, Tuyen T.
• Application Number:
  US09/472,252
• Time in Patent Office: 876 Days
• Field of Search: 335/301-302, 336/200, 336/65, 336/83, 336/96, 336/233, 257/531
• US Class Current: 336/233
• CPC Class Codes: H01F 2003/106 Magnetic circuits using combinations of different magnetic materials
• CPC Class Codes: H01F 2017/048 with encapsulating core, e.g. made of resin and magnetic powder
• CPC Class Codes: H01F 27/022 Encapsulation
• 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 3/08 made from powder powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06

Abstract

A magnetic element including: a composite magnetic member A containing a metallic magnetic powder in an amount of 50-70 vol. % and a thermosetting resin in an amount of 50-30 vol. %; a magnetic member B that is at least one selected from a ferrite sintered body and a pressed-powder magnetic body of a metallic magnetic powder; and a coil. The magnetic element is characterized in that a magnetic path determined by an arrangement of the coil passes the magnetic member A and the magnetic member B in series and the coil is embedded in the magnetic member A. The present invention also provides a method for manufacturing the magnetic element.

Claims

1. A magnetic element, comprising:

a composite A containing a metallic magnetic powder in the amount of 50-70 vol. % with the remainder being a thermosetting resin;

a magnetic member B that is at least one selected from a ferrite sintered body and a pressed-powder magnetic body of a metallic magnetic powder; and

a coil embedded in the composite A;

wherein a magnetic path is defined by a closed loop formed by a magnetic flux, the magnetic path being generated by an electric current that flows through the coil, and being determined by an arrangement of the coil, the composite A and the magnetic member B, the closed loop being formed by the magnetic member B and the composite A, and said magnetic path passes through the closed loop of magnetic member B and composite A.

2. The magnetic element according to claim 1, wherein the coil comprises turns that are spaced to define gaps and the gaps in the coil are filled with the composite A.

3. The magnetic element according to claim 1, wherein the coil is wound around the magnetic member B.

4. The magnetic element according to claim 1, wherein the magnetic member B is positioned outside the composite A in which the coil is embedded.

5. The magnetic element according to claim 4, wherein a plurality of plate-like magnetic members Bare included and are spaced 500 μ

m or less from one another, the composite A in which the coil is embedded is arranged in the space, and the coil is formed of a conductor wound in a planar shape.

6. The magnetic element according to claim 1, wherein the metallic magnetic powder comprises a surface oxide insulating layer.

7. The magnetic element according to claim 6, wherein the metallic magnetic powder contained in the composite A contains Fe as a main component and Al, and the oxide insulating layer on the surface of the metallic magnetic powder is an insulating layer that contains aluminum oxide as a main component and is formed by a heat treatment in the presence of oxygen.