IP Library Granted Patent US 8,835,001
Granted Patent B2
US 8,835,001 · App. 13/431,450 · Granted Sep 16, 2014

Ferrite sintered magnet, motor, and method for producing the ferrite sintered magnet

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Quick Facts
Patent No.
US 8,835,001
App. No.
13/431,450
Granted
Sep 16, 2014
Kind
B2
Abstract

A ferrite sintered magnet has a surface roughness Rz of 3.5 μm or less. A method for producing a ferrite sintered magnet includes: mixing magnetic powders with at least a binder resin to obtain a magnetic powder mixture; injection molding the magnetic powder mixture inside of a mold having a surface roughness of a surface in contact with the magnetic powder mixture of 2.0 μm or less with a magnetic field applied to the mold, to obtain a molded body; and sintering the molded body.

Claims (8)

1. A ferrite sintered magnet comprising an unground surface; wherein a surface roughness Rz of the unground surface is 3.5 μm or less.

2. The ferrite sintered magnet according to claim 1 , wherein the surface roughness Rz is less than 2.0 μm.

3. A motor using the ferrite sintered magnet according to claim 1 .

4. A motor using the ferrite sintered magnet according to claim 2 .

5. A method for producing a ferrite sintered magnet comprising:

mixing magnetic powders with at least a binder resin to obtain a magnetic powder mixture;

injection molding the magnetic powder mixture inside of a mold having a surface roughness Rz of a surface in contact with the magnetic powder mixture of 2.0 μm or less with a magnetic field applied to the mold, to obtain a molded body; and

sintering the molded body.

Assignments (2)
CHANGE OF ADDRESS Recorded Jun 12, 2013
From: TDK CORPORATION
To: TDK CORPORATION
Reel/Frame 030651/0687 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 19, 2012
From: UMEZAWA, HIDEYUKI; MINACHI, YOSHIHIKO; MIZONOUE, OSANORI
To: TDK CORPORATION
Reel/Frame 028093/0716 →