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WO-2026094694-A1 - MAGNETIC BODY, ROTARY APPARATUS, AND METHOD FOR MANUFACTURING MAGNETIC BODY

WO2026094694A1WO 2026094694 A1WO2026094694 A1WO 2026094694A1WO-2026094694-A1

Abstract

Provided is a magnetic body excellent in magnetic force characteristics, a rotary apparatus including the magnetic body, and a method for manufacturing the magnetic body.　A magnet (10) includes a plurality of magnetic particles, has a cylindrical shape extending in an axial direction, and is provided with an end surface (11) facing the axial direction. The end surface (11) is provided with an inner layer (12) and an outer layer (13) in a radial direction. The outer layer (13) and the inner layer (12) are provided with a plurality of magnetic poles (19) in a circumferential direction. The relative density of the magnetic particles exceeds 95%. The inner layer (12) and the outer layer (13) are separated from each other in the radial direction by a boundary (14) defining the inner layer (12) and the outer layer (13).

Inventors

  • KOMURA, HARUHIRO
  • YAMANE, AKIHIRO
  • SUZUKI, TOSHINORI
  • HANASHIMA, Kentaro
  • Okawara, Yu

Assignees

  • ミネベアミツミ株式会社

Dates

Publication Date
20260507
Application Date
20251020
Priority Date
20241029

Claims (19)

  1. It contains multiple magnetic particles, It is cylindrical in shape, extending in the axial direction. The end face is oriented in the axial direction, The end face comprises an inner layer and an outer layer in the radial direction. The outer layer and the inner layer are provided with a plurality of magnetic poles in the circumferential direction. The relative density of the aforementioned magnetic particles exceeds 95%. A magnetic material in which the inner layer and the outer layer are separated by a boundary that defines the inner layer and the outer layer in the radial direction.
  2. The magnetic material according to claim 1, wherein the inner circumferential edge of the end face is rounder than the outer circumferential edge of the end face.
  3. The magnetic material according to claim 1, wherein the outer circumferential edge of the end face is rounder than the inner circumferential edge of the end face.
  4. The magnetic material according to claim 1, wherein the residual magnetic flux density of the end face in the axial direction is greater than that of the outer face in the radial direction.
  5. The magnetic material according to claim 1, wherein the plurality of magnetic particles have portions oriented in directions intersecting the axial direction.
  6. The magnetic material according to claim 1, wherein the inner layer and the outer layer are formed by plastic deformation.
  7. A rotor comprising a magnetic material according to any one of claims 1 to 6, A rotating device comprising a stator facing the rotor.
  8. A process of forming a sintered body by sintering multiple magnetic particles, The process includes a step of forming a plastic body by plastically deforming the sintered body, A method for manufacturing a magnetic material, comprising the step of forming the plastic body, wherein an inner layer of the plastic body and an outer layer of the plastic body are formed on the end face of the plastic body facing in the axial direction, in the radial direction.
  9. The method for producing a magnetic material according to claim 8, wherein the step of forming the plastic body includes a step of heating at a temperature above the liquid phase formation temperature of the magnetic particles.
  10. The method for manufacturing a magnetic material according to claim 9, wherein the temperature is 650°C or higher.
  11. A magnetic material containing multiple magnetic particles, The magnetic material is a cylinder extending in the axial direction, The cylinder has an outer circumferential surface and an inner circumferential surface. The outer or inner circumferential surface is provided with a plurality of magnetic poles arranged in the circumferential direction. The relative density of the aforementioned magnetic particles exceeds 95%. The outer circumferential surface or the inner circumferential surface has, in the radial direction, a region where the distance from the outer circumferential surface to the inner circumferential surface is short, and a region where the distance is long. A magnetic material in which a region with a long distance exists between a plurality of magnetic poles formed in a region with a short distance.
  12. The magnetic material according to claim 11, wherein, in the circumferential direction, there is a boundary between the region with a short distance and the region with a long distance.
  13. The magnetic material according to claim 11 or 12, wherein the region with a shorter distance is more anisotropic than the region with a longer distance.
  14. The magnetic material according to claim 11 or 12, wherein the plurality of magnetic particles have portions oriented in directions intersecting the axial direction.
  15. The magnetic material according to claim 11 or 12, wherein the region with the short distance is formed by plastic deformation.
  16. A rotor comprising a magnetic material according to any one of claims 11 to 15, A rotating device comprising a stator facing the rotor.
  17. A process of forming a sintered body by sintering multiple magnetic particles, The process includes a step of forming a plastic body by plastically deforming the sintered body, On the radially oriented outer or inner surface of the plastic body, a region is formed in the radial direction where the distance from the outer surface to the inner surface is short, and a region where the distance is long. A method for manufacturing a magnetic material, comprising the step of magnetizing the material such that the region with the shortest distance becomes a pole.
  18. The method for producing a magnetic material according to claim 17, wherein the step of forming the plastic body includes a step of heating at a temperature above the liquid phase formation temperature of the magnetic particles.
  19. The method for manufacturing a magnetic material according to claim 18, wherein the temperature is 650°C or higher.

Description

Magnetic material, rotating machinery, and method for manufacturing magnetic material This invention relates to a magnetic material, a rotating device, and a method for manufacturing a magnetic material. Rare-earth magnets, which use rare-earth elements as magnetic materials, are known (see, for example, Patent Document 1). This is a schematic cross-sectional view showing a part of an example of a rotating device equipped with a magnetic material according to the first embodiment.This is a schematic perspective view showing the magnetic material according to the first embodiment.Figure 2 is a cross-sectional view of the magnetic material along its axial direction.Figure 2 is a diagram illustrating the magnetization of the magnetic material shown.This is a flowchart illustrating the manufacturing method of magnetic materials.This is a diagram illustrating the second step shown in Figure 5.This diagram illustrates the initial stages of the third process shown in Figure 5.Figure 5 is a diagram illustrating the final stage of the third process.This is a cross-sectional view of the magnetic material according to the second embodiment, along the axial direction.This figure illustrates the initial stage of the third step in the method for manufacturing a magnetic material according to the second embodiment.This is a diagram illustrating the final stage of the third step in the method for manufacturing a magnetic material according to the second embodiment.This diagram schematically shows the magnetic material according to the third embodiment as viewed from the axial direction.This is an axial cross-sectional view illustrating the initial stage of the third step in the method for manufacturing a magnetic material according to the third embodiment.This is a radial cross-sectional view illustrating the third step in the manufacturing method of a magnetic material according to the third embodiment.This is a cross-sectional view along the axial direction illustrating the final stage of the third step in the manufacturing method of a magnetic material according to the third embodiment.This figure schematically shows the magnetic material according to the fourth embodiment as viewed from the axial direction.This is an axial cross-sectional view illustrating the initial stage of the third step in the method for manufacturing a magnetic material according to the fourth embodiment.This is a radial cross-sectional view illustrating the third step in the method for manufacturing a magnetic material according to the fourth embodiment.This is a diagram based on a photograph of the first plastic body according to the embodiment.This is a diagram from the photograph in Figure 19, with the dashed lines indicating the boundary removed.This is a diagram based on a photograph of the second plastic body according to the embodiment.This is a diagram with the boundary dashed lines removed from the photograph in Figure 20.This graph illustrates the surface magnetic flux density (magnetic properties) of the magnetic material according to the example.This graph illustrates the magnetostatic properties of the magnetic material in the magnetization direction according to the embodiment.This graph illustrates the magnetostatic properties of the magnetic material in the vertical direction according to the embodiment. The following examples illustrate embodiments for carrying out the magnetic material, rotating device, and method for manufacturing the magnetic material according to the present invention, with reference to the accompanying drawings. The embodiments illustrated below are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention can be modified and improved upon from the following embodiments without departing from its spirit. Furthermore, in the accompanying drawings, the dimensions of each component may be exaggerated or reduced, or hatching may be omitted, for the sake of ease of understanding. (First Embodiment) Figure 1 is a schematic cross-sectional view showing a part of an example of a rotating device equipped with a magnetic material according to the first embodiment. More specifically, Figure 1 is a cross-sectional view showing a part of a motor 1, which is an example of a motor as a rotating device. As shown in Figure 1, the motor 1 comprises a housing 2 (motor case), a shaft 3, a bearing Be, a stator 4, and a rotor 8. Hereinafter, the direction in which the shaft 3 extends will be referred to as the "axial direction." The direction intersecting the central axis of the shaft 3 and perpendicular to the axial direction will be referred to as the "radial direction." In the radial direction, the side closer to the central axis of the shaft 3 may be referred to as the "inside," and the side further from the central axis of the shaft 3 may be referred to as the "outside." Furthermore, the circumferential direction of a circle centered on the central