Method of producing powder magnetic core and method of producing magnetic core powder

Patent metadata

Field	Value
Publication number	US-9159489-B2
Application number	US-201113811489-A
Country	US
Kind code	B2
Filing date	Jul 20, 2011
Priority date	Jul 23, 2010
Publication date	Oct 13, 2015
Grant date	Oct 13, 2015

Abstract

The invention includes: powder preparation step of obtaining magnetic core powders by mixing, of magnetic powders with thermosetting resin powders in hot state; powder filling step of filling the obtained magnetic core powders into a die; a compaction step of compacting magnetic core powders; and compact heating step of heating, compacts to the elevated temperature state at which the thermosetting resin hardens after compaction.

First claim

The invention claimed is:

1. A method of producing a powder magnetic core, comprising:
obtaining a magnetic core powder by mixing magnetic powder with a thermosetting resin powder in hot state at temperature that brings a viscosity of the thermosetting resin powder to less than or equal to 10 4 Pa-s such that a resin film is formed on particle surfaces of the magnetic core powder, the temperature being equal to or higher than a compacting temperature and being less than an initial hardening temperature of the thermosetting resin powder;
cooling the obtained magnetic core powder;
filling the cooled magnetic core powder into a preheated die;
compacting the filled magnetic core powder at the compacting temperature to obtain a compact; and
heating the obtained compact into a state in which the thermosetting resin powder hardens.

2. The method of producing the powder magnetic core according to claim 1 , wherein the mixing, the magnetic powder with the thermosetting resin powder includes mixing the magnetic powder with the thermosetting resin powder at a temperature that is at least 10° C. higher than an initial softening temperature of the thermosetting resin powder and not more than 130° C. higher than the initial softening temperature of the thermosetting resin powder.

3. The method of producing the powder magnetic core according to claim 1 , wherein a blending proportion for the thermosetting resin powder, when mixing the magnetic powder with resin powder in the hot state, is more than 0.1 mass % and not more than 3 mass % in where a total magnetic core powder is defined as 100 mass %.

4. The method of producing the powder magnetic core according to claim 1 , wherein the thermosetting resin powder is made of a thermosetting silicone resin.

5. The method of producing the powder magnetic core according to claim 1 , further comprising:
bringing the surface of the magnetic powder into contact with silane coupling agents; and
drying the magnetic powder whose surface has been brought into contact with the silane coupling agent.

Assignees

• Hwang Junghwan
• Hattori Takeshi
• Hirano Masaki
• Sugiyama Masaki
• Oishi Yusuke
• Okamoto Daisuke
• Yamamoto Hidenari
• Toyota Motor Co Ltd

Inventors

• Hwang Junghwan
• Hattori Takeshi
• Hirano Masaki
• Sugiyama Masaki
• Oishi Yusuke
• Okamoto Daisuke
• Yamamoto Hidenari

Classifications

• B22F1/108

  Mixtures obtained by warm mixing · CPC title

• C22C2202/02

  Magnetic · CPC title

• H01F41/0266

  Moulding; Pressing (H01F41/0273 takes precedence; hard magnetic particles H01F1/06, H01F1/11) · CPC title

• H01F27/255

  made from particles (H01F27/26 takes precedence) · CPC title

• H01F41/0246 Primary

  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) · CPC title