Ring type sintered magnet

A sintered magnet, ring-shaped technology, applied in the direction of magnetic circuit, magnetic circuit shape/style/structure, magnetic material, etc., can solve problems such as poor shape accuracy, reduce motor current, increase torque, and reduce unevenness Effect

Inactive Publication Date: 2006-05-10
MITSUBISHI ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] On the other hand, for rare earth sintered magnets that can obtain strong magnetic force, in the production method, it is necessary to form the pulverized powder in a magnetic field molding machine and then sinter it, so the shape accuracy after sintering is usually not good.

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0059] FIG. 1 is a perspective view showing an annular sintered magnet according to Embodiment 1 of the present invention. The magnet 10 according to this embodiment is a ring-shaped sintered magnet mainly composed of neodymium (Nd), iron (Fe), and boron (B). The recesses 11 and protrusions 12 are periodically formed in the outer diameter circumferential direction of the annular sintered magnet 10 . In the ring-shaped sintered magnet of FIG. 1 , eight recesses 11 and protrusions 12 are provided at predetermined angular intervals (45-degree intervals), respectively.

[0060] The uneven shape is formed by rotating and twisting at a predetermined angle with respect to the axial direction of the ring magnet 10 . In addition, the magnetic poles of the ring-shaped sintered magnet 10 are formed by rotating and twisting at a predetermined angle with respect to the axial direction along the above-mentioned concavo-convex shape, and are usually twisted and magnetized. Furthermore, the...

Embodiment approach 2

[0069] The ring-shaped sintered magnet of this embodiment is the same as that of Embodiment 1. It is a ring-shaped sintered magnet mainly composed of neodymium, iron, and boron, and has a concave-convex shape on the outer periphery of the ring. The concavo-convex shape is formed by rotating and twisting at a predetermined angle with respect to the axial direction. In addition, the magnetic poles of the magnet are formed along the concavo-convex shape, and the boundaries of the magnetic poles are provided in the concave portions. This embodiment is characterized in that the outermost periphery of the convex shape of the outer diameter of the magnet is constituted by a part (arc) of a circle centered on the center of the inner diameter of the ring, that is, the rotating shaft.

[0070] The ring-shaped sintered magnet of this embodiment is manufactured by a powder sintering method in which a magnetic field is applied to magnetic powder, compression-molded, and then sintered and h...

Embodiment approach 3

[0074] figure 2 It is a perspective view showing the annular sintered magnet according to Embodiment 3 of the present invention. The ring-shaped sintered magnet 20 of this embodiment is the same as the first embodiment, and is a sintered magnet mainly composed of neodymium, iron, and boron. The concavo-convex shape is formed by rotating and twisting at a predetermined angle with respect to the axial direction.

[0075] Additionally, if image 3 As shown, the magnetic poles of the ring-shaped sintered magnet 20 are formed by rotating and twisting at a predetermined angle with respect to the axial direction along the concave-convex shape. Magnetic pole boundaries (shown by dotted lines in the figure) are disposed in the concave portion 21 . In addition, all the protrusions 22 on the outer periphery of the ring are constituted by a part (arc) 23 of a circle having the same center as the center of the inner diameter of the ring, that is, the center of the rotating shaft.

[00...

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Abstract

A ring-shaped sintered magnet made of rare earths with strong magnetic force, and a concave-convex part formed on the outer circumference of the ring. By twisting the concave-convex part in the axial direction, in addition to reducing the deformation of the magnetization distribution in the rotation direction, it can also reduce the cogging torque. the goal of. In the ring-shaped sintered magnet manufactured by orienting the magnetic powder through a magnetic field, compression molding, and sintering, periodic concave-convex shapes (21, 22) are formed on the outer circumference of the ring at least in a part of the axial direction of the ring. (21, 22) The magnetic poles of the magnet are periodically formed along the concave-convex shape (21, 22) while varying with the position in the axial direction, and the magnetic pole boundaries are provided in the concave portion (21). In particular, the concavo-convex shape (21, 22) is rotated in the axial direction and formed obliquely. In addition, the concavo-convex shape (21, 22) is formed in a waveform close to the absolute value of a sine wave.

Description

technical field [0001] The present invention relates to the structure of ring-shaped sintered magnets made by orienting magnetic powder through magnetic field, and going through compression molding and sintering processes. Background technique [0002] For the radially oriented ring magnets used in the inner rotor of permanent magnet motors, in order to reduce the rotation unevenness such as cogging torque, the magnetic poles are often inclined to the axial direction to form magnetic poles and to perform skew magnetization. However, the magnetization distribution of radially oriented ring magnets is rectangular and often contains distortion caused by high-level components, so that only skew magnetization often cannot achieve the effect of sufficiently mitigating cogging torque. [0003] Therefore, as shown in Patent Document 1 or Patent Document 2, conventionally, there is a method of forming unevenness on the outer periphery of a ring magnet and twisting the unevenness with...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02K1/27
CPCB22F7/062H01F1/086H01F41/028H02K1/2733H02K15/03
Inventor 石见泰造鹈饲义一中原裕治
Owner MITSUBISHI ELECTRIC CORP
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