Bonded magnet, bonded magnet component, and bonded magnet production method

Patent metadata

Field	Value
Publication number	US-10832863-B2
Application number	US-201715404501-A
Country	US
Kind code	B2
Filing date	Jan 12, 2017
Priority date	Sep 30, 2014
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

A bonded magnet is provided which includes first and second components. The first and second components have first and second non-action surfaces, and first and second action surfaces that intersect the first and second non-action surfaces, respectively. First and second flux groups curve inside the first and second components from the first and second non-action surfaces to the first and second action surfaces, respectively. The areas of the first and second non-action surfaces are greater than the first and second action surfaces, respectively. The flux densities on the first and second action surfaces are higher than the first and second non-action surfaces, respectively. The pole on the first non-action surface is opposite to the second non-action surface. The first and second non-action surfaces are coupled to each other. The first flux groups continuously extend from one to another.

First claim

What is claimed is:

1. A method for producing a bonded magnet having a first non-action surface, a first action surface that is connected to said first non-action surface through a connection portion, and a third non-action surface that is connected to said first action surface through a connection portion and is connected to said first non-action surface through a connection portion, the bonded magnet having a substantially sector exterior shape, which is defined by said first non-action surface, the third non-action surface and the first action surface in a cross-sectional view, and has a predetermined central angle θ 0 which is formed by said first non-action surface and said third non-action surface, the method comprising:
charging a bond magnet composition that contains a magnetic material and a resin into a molding die cavity; and
forming the bonded magnet while applying an external magnetic field to said cavity, wherein
said external magnetic field is formed by permanent magnets,
a first non-action-surface magnetizing magnet, a third non-action-surface magnetizing magnet, and a first action-surface magnetizing magnet as the permanent magnets are arranged to face parts corresponding to said first non-action surface, said third non-action surface, and said first action surface, respectively,
the magnetic pole of said first non-action-surface magnetizing magnet on said corresponding part is the same as the magnetic pole of said third non-action-surface magnetizing magnet on said corresponding part,
the magnetic pole of said first action-surface magnetizing magnet on said corresponding part is opposite to the magnetic pole of said first non-action-surface magnetizing magnet and said third non-action-surface magnetizing magnet on said corresponding parts,
the first action surface corresponds to an arc of the substantially sector exterior shape in the cross-sectional view,
the substantially sector exterior shape is a part of a circle having a center,
a first line from the center to an end of the first action-surface magnetizing magnet intersects with the first action surface at a first point on the first action surface in the cross-sectional view,
a second line from the center to another end of the first action-surface magnetizing magnet intersects with the first action surface at a second point on the first action surface in the cross-sectional view, and
a ratio A/B satisfies:
0.3184n≤A/B<−0.04n 3 +1.47n 2 −14.03n+43, when a total number n of poles of said bonded magnet is not greater than 12 and said central angle θ 0 is equal to or greater than 30°, and
0.3184n≤A/B, when the total number n of poles of said bonded magnet is greater than 12 and said central angle θ 0 is less than 30°,
wherein B denotes a half of an arc length of a segment on the first action surface in the cross-sectional view starting at the first point and ending at the second point, and A equals to a length of the first non-action surface corresponding to the first non-action-surface magnetizing magnet in the cross-sectional view.

2. The method for producing a bonded magnet according to claim 1 , wherein said central angle is 90 degrees or less.

3. The method for producing a bonded magnet according to claim 1 , wherein said first non-action-surface magnetizing magnet is positioned adjacent to said first action-surface magnetizing magnet, said first action-surface magnetizing magnet is positioned adjacent to the third non-action-surface magnetizing magnet, said third non-action-surface magnetizing magnet is positioned adjacent to said first non-action-surface magnetizing magnet.

4. The method for producing a bonded magnet according to claim 1 , the method further comprising:
connecting a plurality of said bonded magnet with said substantially sector exterior shape to form a cylindrical columnar bonded magnet assembly with a bottom surface substantially circular.

5. The method for producing a bonded magnet according to claim 1 , wherein magnetizing magnets are arranged to face only three parts corresponding to a first non-action surface, a first action surface, and a third non-action surface.

6. The method for producing a bonded magnet according to claim 4 , the method further comprising:
connecting a plurality of said bonded magnet with said substantially sector exterior shape to form said cylindrical columnar bonded magnet assembly having a solid central area with the bottom surface substantially circular.

7. The method for producing a bonded magnet according to claim 1 , wherein the length of the first non-action surface is longer than a length of the first action surface in the cross-sectional view.

8. The method for producing a bonded magnet according to claim 1 , wherein the first non-action surface and the third non-action surface converge at the center in the cross-sectional view.

Assignees

• Nichia Corp

Inventors

• Yoshida Rie
• Kume Michiya
• Ihara Kohei
• Ichimori Taku

Classifications

• H01F7/021 Primary

  Construction of PM (H01F7/0278 takes precedence; PM compositions H01F1/032) · CPC title

• H02K1/06

  characterised by the shape, form or construction · CPC title

• H01F41/0273

  Imparting anisotropy (methods and devices for magnetising permanent magnets H01F13/003) · CPC title

• H01F3/08 Primary

  made from powder (powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06) · CPC title

• H01F41/0266 Primary

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