Inductor

• US 5,530,416 A
• Filed: 12/06/1994
• Issued: 06/25/1996
• Est. Priority Date: 12/10/1993
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Wakamatsu, Shinji, Morinaga, Tetsuya
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): LORD, GEORGE
• Application Number:
  US08/354,091
• Time in Patent Office: 567 Days
• Field of Search: 336/192, 336/233, 335/297
• US Class Current: 336/192
• 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 2017/048 with encapsulating core, e.g. made of resin and magnetic powder
• CPC Class Codes: H01F 41/0246 Manufacturing of magnetic circuits by moulding or by pressing powder magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36

Abstract

An inductor which has a ferrite core and a coil wound around the ferrite core. The ferrite core is coated with borosilicate zinc glass. The ferrite core is produced by: adding a low-temperature-sintered oxidized metal, such as BiO₂ and PbO, and a resin binder to ferrite powder of Mn, Fe, Co, Ni or the like; mixing the materials together; compression molding the mixture; and sintering the molded article in a low temperature.

Claims

1. An inductor comprising:

a ferrite core which includes low-temperature-sintered BiO₂ and/or PbO, the ferrite core having a body and flange;

a glass coating on the ferrite core, the glass coating covering at least a portion which is in contact with a flux in soldering; and

a conductive coil which is wound around the body of the ferrite core.

2. An inductor as claimed in claim 1, wherein the ferrite core includes at least one of Mn, Fe, Co, and Ni.

3. An inductor as claimed in claim 1 wherein the ferrite core includes mainly Ni, Zn, Fe₂ O₃.

4. An inductor as claimed in claim 1, wherein the glass coating is borosilicate zinc or borosilicate lead.

5. Method for producing an inductor comprising the steps of:

adding a low-temperature sintered BiO₂ and/or PbO to ferrite powder;

mixing the low-temperature sintered BiO₂ and/or PbO with the ferrite powder;

compression molding the mixed low-temperature sintered BiO₂ and/or PbO and ferrite powder into a ferrite core having a body and a flange;

sintering the ferrite core;

forming a glass coating on the sintered ferrite core, the glass coating covering at least a portion of the ferrite core which is to contact solder flux; and

winding a conductive coil around the body of the ferrite core.