Production method for permanent magnet, and production device for permanent magnet

Patent metadata

Field	Value
Publication number	US-10020098-B2
Application number	US-201314414729-A
Country	US
Kind code	B2
Filing date	Sep 5, 2013
Priority date	Sep 6, 2012
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

In a production method for permanent magnet, a magnetic powder is loaded into a cavity formed in a groove shape whose longitudinal direction horizontally extends. A loading step of loading the magnetic powder includes a first loading step of loading, of the magnetic powder, a first magnetic powder containing no heavy rare earth element or containing a heavy rare earth element, and a second loading step of loading, of the magnetic powder, a second magnetic powder having a higher content rate of heavy rare earth element than that of the first magnetic powder, at a predetermined position in the cavity.

First claim

The invention claimed is:

1. A production method for a permanent magnet, comprising:
a loading step of loading a magnetic powder into a cavity formed by a mold; and
a pressurizing step of pressurizing the magnetic powder in the cavity, thereby compressing and molding the magnetic powder, wherein
the cavity is formed in a groove shape such that a longitudinal direction of the cavity extends in a horizontal direction, and
the loading step includes
a first loading step of loading a first magnetic powder of the magnetic powder,
a second loading step of loading, of the magnetic powder, a second magnetic powder at a predetermined position in the cavity, a content rate of the heavy rare earth element in the second magnetic powder being higher than that in the first magnetic powder,
a first closing step of, before the pressurizing step and after the first loading step, closing the cavity with a first lid portion which has a preliminary molding portion with a protrusion formed at the predetermined position at a cavity side, and depressing the first magnetic powder in the cavity by the preliminary molding portion, thereby transferring a shape of the preliminary molding portion and molding the first magnetic powder in which a dent is formed at the predetermined position, and
a second closing step of, after the second loading step, closing the cavity with a second lid portion which has a molding portion at the cavity side, and depressing the magnetic powder in the cavity by the molding portion, thereby transferring a shape of the molding portion and molding the magnetic powder.

2. The production method for a permanent magnet according to claim 1 , wherein
the second magnetic powder includes a plural kinds of the second magnetic powders having different content rates of the heavy rare earth element, and
in the second loading step, the second magnetic powders are loaded into the cavity, in order from the lowest content rate of the heavy rare earth element.

3. The production method for a permanent magnet according to claim 1 , wherein the predetermined position is a position extending along a longitudinal inner wall of the cavity.

4. The production method for a permanent magnet according to claim 1 , further comprising a magnetic field agitation step of applying a magnetic field in a direction perpendicular to the horizontal direction of the cavity, to the magnetic powder loaded in the cavity, thereby agitating the magnetic powder.

5. The production method for a permanent magnet according to claim 1 , further comprising a rod agitation step of agitating the magnetic powder loaded in the cavity, by a nonmagnetic rod portion, so that the magnetic powder is uniformly loaded.

6. The production method for a permanent magnet according to claim 1 , further comprising a swing step of swinging the magnetic powder loaded in the cavity.

7. The production method for a permanent magnet according to claim 1 , further comprising an orientation step of applying a magnetic field in a direction perpendicular to the horizontal direction of the cavity, to the magnetic powder loaded in the cavity, thereby orienting the magnetic powder.

8. The production method for a permanent magnet according to claim 1 , further comprising a sintering step of sintering the magnetic powder loaded in the cavity, after the pressurizing step.

9. A production device for a permanent magnet, in which a magnetic powder is loaded into a cavity formed in a mold and the magnetic powder in the cavity is pressurized, whereby the magnetic powder is compressed and molded, comprising:
a mold including a cavity wherein the cavity is formed in a groove shape such that a longitudinal direction of the cavity extends in a horizontal direction;
a first lid portion provided above the cavity and configured to close the cavity with the magnetic powder loaded therein, the first lid portion having a preliminary molding portion with a protrusion formed at a predetermined position at a cavity side wherein
the preliminary molding portion is configured to, by depressing the magnetic powder in the cavity with the preliminary molding portion from above, transfer a shape of the preliminary molding portion and mold the magnetic powder in which a dent recessed downward is formed at the predetermined position on the upper surface of the magnetic powder; and
a second lid portion provided above the cavity and configured to close the cavity with the magnetic powder loaded therein after the first lid portion has formed the dent at the predetermined position, the second lid portion having a molding portion at the cavity side, wherein
the molding portion is configured to, by depressing the magnetic powder in the cavity with the molding portion from above, transfer a shape of the molding portion and mold the magnetic powder.

10. The production device for a permanent magnet according to claim 9 , wherein the protrusion is formed at a position extending along a longitudinal inner wall of the cavity.

11. The production device for a permanent magnet according to claim 9 , further comprising:
a magnetic field generating portion for generating a magnetic field in a direction perpendicular to a longitudinal direction of the cavity, the magnetic field generating portion composed of a pair of electromagnets placed above and below the cavity so as to be opposed to each other.

12. The production device for a permanent magnet according to claim 9 , wherein the mold is detachable from the production device.

Assignees

• Mitsubishi Electric Corp

Inventors

• Furusawa Kimiyasu
• Ugai Yoshikazu
• Akita Hiroyuki

Classifications

• B22F7/02

  of composite layers {(B22F7/002 takes precedence)} · CPC title

• H01F41/0266

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

• C22C38/002

  containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60 · CPC title

• B30B15/302

  Feeding material in particulate or plastic state to moulding presses · CPC title

• H01F1/0536 Primary

  sintered · CPC title