JPS6028376B2 - Manufacturing method for rolled magnets - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a rolled magnet with a multi-pole outer circumference using an extruded heterotropic composite ferrite magnet, in which the magnetic pole positions and the space between the poles are all aligned in an effective magnetic orientation. The objective is to provide a material that is molded to improve the surface magnetic flux density.

As shown in FIG. 1, a conventional roll-shaped magnet has been used in which an isotropic ferrite magnet 2 formed into a pipe shape and sintered is fixed to the outer peripheral surface of a shaft 1.

With this configuration, there is a limit to the manufacturing dimensions because the dimensional distortion due to dawn shrinkage is large and the distortion becomes larger as the thinner and longer the pipe becomes longer.Due to the distortion of the pipe-shaped center hole, it is difficult to mate with the shaft 1 and the adhesion is poor. Since the specific gravity as a magnet is as high as 5.0 and a striation process is required, soot tends to form inside the magnet, causing variations in surface magnetic flux density.

In addition, as another conventional example, as shown in FIG. 2, magnetically anisotropic fan-shaped Akira silk magnets 3 having ferromagnetism are pasted at predetermined positions on the surface of the shaft 1 from the outer periphery toward the center, as many as the number of magnetic poles. Some did.

However, even in this configuration, since the anisotropic magnet 3 is used, the material is expensive and the process is complicated, resulting in a cost disadvantage. This requires advanced construction methods such as magnet polishing and bonding, and when longer rolled magnets are required, due to processing limitations, magnets that have been split in all directions are spliced together, reducing the magnetic force at the joint. There were drawbacks. The present invention eliminates the drawbacks of the prior art as described above.

Embodiments of the present invention will be described below with reference to FIGS. 3 to 8.

First, as shown in FIG. 3, a magnet 6 is obtained by extruding a mixture of ferrite particles 4 subjected to magnetic anisotropy treatment and a medium 5 of rubber and/or synthetic resin for bonding the ferrite particles 4.

Since the magnetic orientation of the magnet 6 is oriented along the flow of the ferrite particles 4, ferromagnetism occurs in the thickness direction a of the magnet 6 with respect to the extrusion direction b, as shown by the B-day curve in FIG. The magnetic properties of the extrusion-oriented anisotropic magnet 6 are such that the ferrite particles 4
It is said that the orientation ratio will not decrease if the blending amount is 80 to 90% by weight and the maximum magnetic energy (BHmax) is obtained, and the thickness of the molded material is 5.0 or less.

In forming a roll-shaped magnet using this extrusion-oriented composite ferrite magnet, the present invention makes effective use of the ferromagnetic direction of the magnetically anisotropic magnet, so that ferromagnetism is concentrated at the necessary magnetic poles on the surface of the roll-shaped magnet. The purpose is to obtain a roll-shaped magnet that is oriented in this manner.

For example, assuming that the surface magnetic poles of a rolled magnet are 8 poles symmetrical, as shown in FIG. The fan-shaped magnet body 8 is formed by extrusion molding using the method shown in FIG. 3, and is composed of three magnet pieces 9, 10, and 11.

The magnet piece 9 is fan-shaped and has a U-shaped groove 12 on its outer circumferential surface, and the magnet piece 10 has a U-shaped groove on its outer circumferential surface that fits into the groove 12. The magnet piece 11 has a U-shaped inner circumference that fits into the groove 13 and an arcuate outer circumference. The number of divisions of this magnet body 8 is such that the magnetic orientation changes smoothly, and a distance of 90 degrees between poles is most convenient for the magnetic path inside the magnet, so the finer the division, the more effective it is. For roll-shaped magnets having the following shapes, the effect will be exhibited if extrusion molding is carried out individually in at least three stages.

The rolled magnet constructed in this manner is shown in FIG. The magnetic anisotropy of the magnet with this configuration is ferromagnetic in the radial direction 01 at the magnetic pole part n, the angle changes sequentially toward the interpolar part m, and the angle changes sequentially toward the interpolar part m. Since the portion m has ferromagnetism in the circumferential direction P, the entire magnet can be effectively utilized. As another example, as shown in FIG. 7, a magnet body 14 obtained by extrusion molding in which eight U-shaped grooves 12 are formed at equal intervals is attached around the shaft 7, and each of the grooves is Magnet pieces 10 and 11 are extruded into the groove 12.
can be incorporated into a rolled magnet as shown in FIG. With this configuration as well, the same effects as described above can be obtained, and another effect is obtained in that the position of each magnetic pole is reliably regulated and the assembly work is facilitated. The surface magnetic flux density of such a roll-shaped magnet increases to 110-1300 glass when the material with the BHmax=uMQ history described above is fully magnetized, and it surpasses the 600-800 Gauss when it is simply extruded and oriented in a ring shape. It has improved the Japanese style and can be used as a strong magnetic magnet with a magnetic force comparable to, or even higher than, the 1,100 to 1,200 Gauss of the isomeriferous ferrite Akaya magnet shown in FIG.

As described above, according to the manufacturing method of the rolled magnet of the present invention, magnetic anisotropy can be achieved by extrusion molding, eliminating the need for construction methods such as shading, stabilizing the shape, stabilizing the magnetic properties, and significantly reducing the number of man-hours. Composite ferrite material has a specific gravity of 3.5, making it lightweight. Since the entire magnet is effectively utilized, the magnetic flux density at the magnetic poles increases, resulting in strong magnetic force, making it possible to downsize and facilitate post-processing. It has the advantage of being highly reliable without cracking or chipping, and is of great industrial value.

[Brief explanation of the drawing]

Figures 1 and 2 are perspective views of conventional rolled magnets;
FIG. 3 is an explanatory diagram showing the method of manufacturing an anisotropic magnet adopted in the method of manufacturing a rolled magnet of the present invention, FIG. 4 is a B-day characteristic diagram of the anisotropic magnet, and FIG. An explanatory diagram of the assembly process by the same method, FIG. 6 is a side view of a rolled magnet obtained by the same method, FIG. 7 is an explanatory diagram of the assembly process of another example, and FIG. 8 is a roll obtained by the same method. FIG. 3 is a side view of a shaped magnet. 4... Ferrite particles, 5... Medium,
6...Magnet, 7...Shaft, 8...
... Magnet body, 9-11 ... Magnet chip, 12.
...concave groove, 13...concave groove, 14...
...Magnet Qin body. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. In the method of manufacturing a roll-shaped magnet with a multi-pole outer circumference using a magnetically anisotropic composite ferrite magnet that exhibits ferromagnetism perpendicular to the outflow direction of the ferrite particles by extrusion molding a mixture of ferrite particles and a medium, the above A method for producing a roll-shaped magnet, which comprises combining a plurality of extrusion-molded magnet pieces to form a fan-shaped magnet body, and arranging the magnet bodies so that their easy magnetization axes are substantially radial.