Case-integrated bonded magnet and production method for same

Patent metadata

Field	Value
Publication number	US-9312055-B2
Application number	US-201113639723-A
Country	US
Kind code	B2
Filing date	Apr 5, 2011
Priority date	Apr 5, 2010
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

A production method for a case-integrated bonded magnet includes: filling a tubular cavity with a magnet raw material that includes a rare-earth magnet powder and a thermosetting resin binder; heating the magnet raw material to cause the thermosetting resin softened or melted while compressively molding the magnet raw material to obtain a tubular compact; discharging the tubular compact from the tubular cavity while press-fitting the tubular compact into a metal tubular case having an inner peripheral surface coaxial with the tubular cavity; and heat-curing the tubular compact with the tubular case to cure the thermosetting resin. The tubular compact press-fitted into the tubular case is thermally cured thereby causing the tubular compact to transform to a tubular bonded magnet, which expands unexpectedly due to heat.

First claim

The invention claimed is:

1. A production method for a case-integrated bonded magnet comprising:
filling a tubular cavity with a magnet raw material, the magnet raw material including one or more types of rare-earth magnet powder and a thermosetting resin;
heating the magnet raw material to cause the thermosetting resin to be in a softened state or a molten state while compressively molding the magnet raw material to obtain a tubular compact;
discharging the tubular compact from the tubular cavity while press-fitting the tubular compact into a metal tubular case, the metal tubular case having an inner peripheral surface coaxial with the tubular cavity; and
heating the tubular compact with the tubular case to cure the thermosetting resin, wherein
a case-integrated bonded magnet is obtained by integrating the tubular compact with the tubular case.

2. The production method for a case-integrated bonded magnet according to claim 1 , wherein the thermosetting resin includes an epoxy resin.

3. The production method for a case-integrated bonded magnet according to claim 1 , wherein the thermosetting resin is within a range of 1 to 10 mass % of the magnet raw material as a whole.

4. The production method for a case-integrated bonded magnet according to claim 1 , wherein
a press-fitting ratio (Ar) is within a range of 0.0001 to 0.05 when a discharging/press-fitting step is initiated,
the press-fitting ratio is a ratio of a press-fitting margin (Δd) of the tubular compact and an outer diameter (do) of the tubular compact (Δr=Δd/do), and
the press-fitting margin is a dimensional difference between the outer diameter of the tubular compact and an inner diameter (di) of the tubular case (Δd=do−di).

5. The production method for a case-integrated bonded magnet according to claim 1 , wherein a heating/molding step is such that a molding pressure is within a range of 50 to 500 MPa.

6. The production method for a case-integrated bonded magnet according to claim 1 , wherein the tubular case is comprised of a magnetic material.

Assignees

• Honkura Yoshinobu
• Mitarai Hironari
• Matsuoka Hiroshi
• Kato Masayuki
• Okumura Ikuzou
• Aichi Steel Corp

Inventors

• Honkura Yoshinobu
• Mitarai Hironari
• Matsuoka Hiroshi
• Kato Masayuki
• Okumura Ikuzou

Classifications

• H01F1/083

  in a bonding agent · CPC title

• H01F1/28 Primary

  dispersed or suspended in a bonding agent · CPC title

• H02K15/03

  having permanent magnets · CPC title

• H01F1/01

  of inorganic materials (H01F1/44 takes precedence) · CPC title

• H01F41/028

  Radial anisotropy (for rotor or stator bodies H02K15/02) · CPC title