Compression-molding method and device for permanent magnet

Patent metadata

Field	Value
Publication number	US-11756729-B2
Application number	US-202017434415-A
Country	US
Kind code	B2
Filing date	Dec 3, 2020
Priority date	May 25, 2020
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

A compression-molding method for a permanent includes: providing a drive coil to generate an electromagnetic force when a transient current is passed into the drive coil, so as to apply a molding compression force to magnetic powder under compression, and providing an orientation coil to generate an orientation magnetic field when a transient current is passed into the orientation coil, thereby providing the magnetic powder under compression with an anisotropic property; and synchronously passing the transient currents to the drive coil and the orientation coil to synchronously generate the electromagnetic force and the orientation magnetic field, thereby completing compression-molding of the permanent magnet, wherein a magnitude of the electromagnetic force and an intensity of the orientation magnetic field are respectively changed by changing peak values of the transient currents.

First claim

What is claimed is:

1. A compression-molding method for a permanent magnet, comprising:
providing a drive coil to generate an electromagnetic force when a transient current is passed into the drive coil, so as to apply a molding compression force to magnetic powder under compression, and providing an orientation coil to generate an orientation magnetic field when a transient current is passed into the orientation coil, thereby providing the magnetic powder under compression with an anisotropic property; and
synchronously passing the transient currents to the drive coil and the orientation coil to synchronously generate the electromagnetic force and the orientation magnetic field, thereby completing compression-molding of the permanent magnet, wherein a magnitude of the electromagnetic force and an intensity of the orientation magnetic field are respectively changed by changing peak values of the transient currents.

2. The compression-molding method for the permanent magnet as claimed in claim 1 , wherein the drive coil comprises two drive coil sets, in a compression process, transient currents passed into the two drive coil sets are in opposite directions, so that an electromagnetic repulsive force is generated between the two drive coil sets, and the repulsive force drives one of the drive coil sets to drive the compression tool to apply the molding compression force to the magnetic powder under compression.

3. The compression-molding method for the permanent magnet as claimed in claim 1 , wherein the drive coil is a drive coil set, in a compression process, the transient currents synchronously passed into the drive coil set and the orientation coil are in a same direction, an electromagnetic attractive force is generated between the drive coil and the orientation coil, and the attractive force drives the drive coil set to drive the compression tool to apply the molding compression force to the magnetic powder under compression.

4. The compression-molding method for the permanent magnet as claimed in claim 1 , wherein the drive coil is a drive coil set, a drive plate is provided on a side of the drive coil, in a compression process, when the transient current is passed into the drive coil set, an eddy current is generated in the drive plate, so that an electromagnetic repulsive force is generated between the drive coil set and the drive plate, thereby driving the compression tool to apply the molding compression force to the magnetic powder under compression.

5. The compression-molding method for the permanent magnet as claimed in claim 4 , wherein the repulsive force drives the drive plate to drive the compression tool to apply the molding compression force to the magnetic powder under compression.

6. The compression-molding method for the permanent magnet as claimed in claim 4 , wherein the repulsive force drives the drive coil set to drive the compression tool to apply the molding compression force to the magnetic powder under compression.

7. The compression-molding method for the permanent magnet as claimed in claim 6 , wherein the transient currents synchronously passed into the drive coil set and the orientation coil are in a same direction, so that an attractive force is generated between the drive coil and the orientation coil, wherein the attractive force and the repulsive force jointly drive the drive coil set to drive the compression tool to provide the compression force to the magnetic powder under compression.

8. The compression-molding method for the permanent magnet as claimed in claim 2 , wherein a cross-section of the compression tool in an axial direction is in a T shape, and a bottom of the T shape contacts the magnetic powder under compression.

9. The compression-molding method for the permanent magnet as claimed in claim 8 , wherein the drive coil and the orientation coil are both hollow spiral coils and are arranged on a same central axis, wherein the orientation coil is sleeved on an outer periphery of the magnetic powder under compression.

10. The compression-molding method for the permanent magnet as claimed in claim 3 , wherein a cross-section of the compression tool in an axial direction is in a T shape, and a bottom of the T shape contacts the magnetic powder under compression.

11. The compression-molding method for the permanent magnet as claimed in claim 10 , wherein the drive coil and the orientation coil are both hollow spiral coils and are arranged on a same central axis, wherein the orientation coil is sleeved on an outer periphery of the magnetic powder under compression.

12. The compression-molding method for the permanent magnet as claimed in claim 4 , wherein a cross-section of the compression tool in an axial direction is in a T shape, and a bottom of the T shape contacts the magnetic powder under compression.

13. The compression-molding method for the permanent magnet as claimed in claim 12 , wherein the drive coil and the orientation coil are both hollow spiral coils and are arranged on a same central axis, wherein the orientation coil is sleeved on an outer periphery of the magnetic powder under compression.

14. The compression-molding method for the permanent magnet as claimed in claim 5 , wherein a cross-section of the compression tool in an axial direction is in a T shape, and a bottom of the T shape contacts the magnetic powder under compression.

15. The compression-molding method for the permanent magnet as claimed in claim 14 , wherein the drive coil and the orientation coil are both hollow spiral coils and are arranged on a same central axis, wherein the orientation coil is sleeved on an outer periphery of the magnetic powder under compression.

16. The compression-molding method for the permanent magnet as claimed in claim 6 , wherein a cross-section of the compression tool in an axial direction is in a T shape, and a bottom of the T shape contacts the magnetic powder under compression.

17. The compression-molding method for the permanent magnet as claimed in claim 16 , wherein the drive coil and the orientation coil are both hollow spiral coils and are arranged on a same central axis, wherein the orientation coil is sleeved on an outer periphery of the magnetic powder under compression.

18. The compression-molding method for the permanent magnet as claimed in claim 7 , wherein a cross-section of the compression tool in an axial direction is in a T shape, and a bottom of the T shape contacts the magnetic powder under compression.

19. The compression-molding method for the permanent magnet as claimed in claim 18 , wherein the drive coil and the orientation coil are both hollow spiral coils and are arranged on a same central axis, wherein the orientation coil is sleeved on an outer periphery of the magnetic powder under compression.

Assignees

• Univ Huazhong Science Tech

Inventors

• Li Liang
• Lv Yiliang

Classifications

• H01F13/003 Primary

  Methods and devices for magnetising permanent magnets (permanent magnets H01F7/02) · CPC title

• H01F41/0266 Primary

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

• H01F41/0273

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

• B22F3/087

  using high energy impulses, e.g. magnetic field impulses · CPC title

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title