Method for producing rare-earth magnets, and rare-earth-compound application device

Patent metadata

Field	Value
Publication number	US-11424072-B2
Application number	US-202017039514-A
Country	US
Kind code	B2
Filing date	Sep 30, 2020
Priority date	Apr 28, 2015
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

A coating tank 1 provided with a net belt passage opening is prepared, a slurry obtained by dispersing a rare-earth-compound powder in a solvent is continuously supplied to the coating tank 1 to cause the coating tank 1 to overflow, and a plurality of sintered magnet bodies 10 are arranged on a net belt conveyor 5, continuously conveyed horizontally thereon, and passed through the slurry in the coating tank 1 via the net belt passage opening, to apply the slurry to the sintered magnet bodies. The slurry is subsequently dried to continuously apply the powder to the plurality of sintered magnet bodies. As a result, the rare-earth-compound powder can be uniformly applied to the surfaces of the sintered magnet bodies, and the application operation can be performed extremely efficiently.

First claim

The invention claimed is:

1. A device for applying a powder of rare-earth compound onto sintered magnet bodies comprising:
a net belt conveyor linearly conveying the sintered magnet bodies along a horizontal direction;
a box-shaped inner tank having net belt passage openings at two mutually facing side walls individually and accommodating a slurry comprising dispersion a powder of rare-earth compound in a solvent onto the sintered magnet bodies by immersion the magnet bodies in the slurry;
an outer tank receiving the slurry overflowed from the inner tank;
slurry return means for returning the slurry from the outer tank to the inner tank; and
drying means for drying a surface of the sintered magnet bodies discharged from the inner tank to remove the solvent of the slurry so that the powder of rare-earth compound deposited on the surface of the sintered magnet bodies is fixed, wherein
the powder of rare-earth compound is deposited on the surface of the sintered magnet bodies by continuously feeding the slurry to the inner tank, wherein the slurry level in the inner tank is held at a positon higher than an upper surface of the sintered magnet bodies on the net belt conveyor to immerse the sintered magnet into the slurry, continuously overflowing the slurry so as to allow the slurry to be accommodated in the outer tank and circulating the slurry by returning from the outer tank to the inner tank by the slurry return means, horizontally conveying the sintered magnet bodies by means of the net belt conveyor, immersing the sintered magnet bodies in the slurry by introducing the sintered magnet bodies from one of the net belt passage opening of the inner tank into the inner tank and discharging from the other net belt passage opening thereby applying the slurry onto the sintered magnet bodies, and drying with the drying means to remove the solvent of the slurry and to fix deposited powder of rare-earth compound on the surface of the sintered magnet bodies, wherein
the powder of rare-earth compound is selected from the group consisting of an oxide, a fluoride, an oxyfluoride, a hydroxide, and a hydride of R 2 , wherein R 2 is at least one rare-earth element and the sintered magnet bodies are made of R 1 —Fe—B-based composition, wherein R 1 is at least one rare-earth element and heat treated to permit R 2 to be absorbed in the sintered magnet bodies to produce rare-earth permanent magnets.

2. The application device of a rare-earth compound of claim 1 , further comprising:
dripping removal means capable of injecting air against the sintered magnet bodies being horizontally conveyed with the net belt conveyor to remove drippings of the slurry from the surface of the sintered magnet bodies, wherein
the dripping removal means is disposed between the inner tank and the drying means.

3. The device of claim 1 , further comprising:
a pressing net belt covering over the net belt of the net belt conveyor and moving in synchronism with the net belt conveyor, wherein the sintered magnet bodies are held between the pressing net belt cover and the net belt conveyor.

4. The device of claim 1 , wherein a drying zone provided with the drying means, or both the drying zone and a dripping removal zone in which the dripping removal means is provided are covered with a chamber, and a dust collector is further provided for dust collection by suctioning air in the chamber to collect the powder of rare-earth compound removed from the surface of the sintered magnet bodies.

5. The device of claim 1 , further comprising:
a slurry storage tank for once storing the slurry discharged from the outer tank when the slurry is returned from the outer tank to the inner tank by the slurry return means.

6. The device of claim 1 , wherein the device is configured such that a plurality of modules each including the inner tank, the outer tank, the slurry return means, and the drying means are arranged in series, and the sintered magnet bodies on the net belt conveyor are passed through the plurality of the modules to apply the powder of a rare-earth compound and dry plural times.

7. The device of claim 1 , wherein the device is configured such that the net belt of the net belt conveyor has a multitude of protrusions arranged uniformly on an upper surface of the net belt and the sintered magnet bodies are disposed on the multitude of protrusions.

8. The device of claim 1 , wherein the net belt of the net belt conveyor is a net-shaped weave of a metal wire and has a multitude of protrusions, on an upper surface of the net belt projected by folding part of the metal wire in a form of a triangle.

Assignees

• Shinetsu Chemical Co

Inventors

• Kuribayashi Yukihiro
• Kamiya Shogo
• Maegawa Harukazu
• Tanaka Shintaro

Classifications

• B22F3/00

  Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor {; Presses and furnaces} · CPC title

• C22C38/16

  containing copper · CPC title

• B05C13/02

  for particular articles · CPC title

• C22C38/00

  Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00) · CPC title

• C22C38/02

  containing silicon · CPC title