JPS622943Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an anisotropic magnet rotor using an anisotropic magnet fixed to a rotating shaft and having an anisotropy direction in the thickness direction.

Conventionally, in order to improve magnetic properties such as magnetic flux density and coercive force of a magnet rotor, various magnet rotors in which anisotropic magnets are fixed to the outer periphery of a core metal have been proposed. For example, (a) Japanese Patent Publication No. 48-14806 ``Float motor'', (b) Japanese Patent Publication No. 49-50414 ``Pulse motor'',
(c) Japanese Patent Application Laid-open No. 15012/1983, ``Method for manufacturing a rotor,'' etc.

However, in (a), a rotor is shown in which rectangular permanent magnets are fixed radially to a cylindrical base, and if the magnets are made thicker, the spacing between the magnets becomes larger, the output is degraded relative to the rotor diameter, and the strength against high speeds is reduced. inferior,
There are drawbacks such as difficulty in magnetizing after molding. Also
(B) shows a rotor in which fan-shaped anisotropic magnets are bonded annularly and radially around the shaft, but since the magnets are bonded together, precision is required for the contact surfaces, and production It is difficult to remove and assemble, it is troublesome to bond during production, it is difficult to ensure stable strength against high-speed rotation, and defects are likely to occur.

Furthermore, in (c), a fan-shaped magnet is die-cast and fixed to the yoke on the outer circumference of the shaft, and it is shown that it is magnetized after molding, but it is difficult to make multipoles with a single chip chip, and when the magnet is brought against it, ) has the same drawbacks,
If they are separated, it will be troublesome to position the chips, and the drawback is that the chips cannot be brought close to each other. Furthermore, none of these proposals has been put into practical use, and they all have the problem of being unsuitable for mass production or automatic assembly.

Therefore, we have developed a magnet rotor that eliminates these drawbacks, allows easy and accurate positioning of magnet chips, automatically feeds magnet chips, and ensures fixing strength.
It was proposed as a ``magnetic rotor'' in Utility Model Application No. 55-81757 (Utility Model Application No. 57-7881). This content is based on a rotor in which anisotropic magnets are fixed radially to a magnetic core metal fixed to a rotating shaft, and the magnets are fan-shaped or trapezoidal and have parallel surfaces on their outer sides, and their respective sides are spaced adjacent to each other. They are arranged radially facing each other, synthetic resin is poured into the spaced parts and solidified to integrate them, and the outer periphery is polished into a cylindrical shape.

According to this proposal, since it can be made with multiple poles, the rotation angle per pulse becomes smaller, the resolution increases, and high-precision control is possible.If an anisotropic magnet is used for this, even a small rotor with multiple poles can be used. Although it has the advantages of high torque and excellent practicality, it suffers from poor assembly due to the small size of the magnet, difficulty in processing such a small magnet itself, and a poor material yield due to this. is undeniable.

The present invention was developed in view of this point, and it is possible to achieve anisotropy in a rotor in which a plurality of anisotropic magnets of the same shape are arranged radially around a magnetic core fixed to a rotating shaft. Anisotropic magnets whose direction is the thickness direction are used, and an even number of 4 or more magnets are arranged radially, and each magnet is magnetized with an odd number of 3 or more poles. .

Next, one embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 indicates anisotropic magnets, and in this embodiment, eight magnets are arranged to form a circle. This anisotropic magnet 1 has parallel surfaces 1a, 1a, and an inclined surface 1 facing the center after assembly.
b, 1b, and is anisotropic in the thickness direction.
Consists of sintered ferrite chips. This chip is manufactured by cutting out a rectangular body (anisotropically treated sintered product) of an appropriate size so that the anisotropy direction is the thickness direction.

Such anisotropic magnets 1 are arranged radially as shown on a core metal 2 made of an octagonal magnetic material, and are integrated by filling with a synthetic resin material 3.
After that, the anisotropic magnet 1 is polished from the outer periphery to the finish line 4 to become cylindrical, and then the boss 5
The rotating shaft 6 is press-fitted through the magnet rotor to produce a magnet rotor.

After the rotor 6 is press-fitted into the anisotropic magnet 1, the N-S-
It is divided into three poles and magnetized into N or S-N-S. When the anisotropic magnet 1 is multi-pole magnetized in this way, it is anisotropic in the thickness direction as described above, so the anisotropy direction of the anisotropic magnet 1 on the surface of the cylinder is the same as that of the odd numbered magnetic poles. If so, the lines of action of the magnetic lines of force due to the central magnetization will pass through the center of rotation, and the magnetic force that contributes to the rotational force will effectively act. In addition, the left and right parts are deviated from the center of rotation, and the effect of magnetic force is slightly weakened, but in this invention, an even number of anisotropic magnets 1 are provided, and the number of N poles and S poles is equal. , the magnetic balance will not be lost.

In the embodiment described above, the anisotropic magnet 1
Although this is divided into three poles and magnetized, it may be magnetized with five poles. Further, the number of anisotropic magnets 1 is not limited to eight, and may be any other even number. In addition, since the magnets used are anisotropic in the thickness direction (parallel), even small-diameter rotors with a diameter of about 10 mm can be used.
If there are not at least four anisotropic magnets 1, it will not be possible to arrange them radially.

Since the present invention is configured as described above, it has the following effects.

Since multiple poles can be magnetized with one magnetic force, the number of magnets can be reduced, manufacturing is easier, and the yield of materials is improved, eliminating waste.

Since the number of magnets is an even number, the strength of magnetization is NS.
The number is the same, so the overall magnetic balance will not be disrupted.

[Brief explanation of the drawing]

FIG. 1 is a front view of an anisotropic magnet rotor according to the present invention, and FIG. 2 is a longitudinal sectional view of the rotor shown in FIG. 1... Anisotropic magnet, 2... Core metal, 5... Boss,
6...Rotation axis.

Claims (1)

[Scope of utility model registration request] In a rotor in which a plurality of anisotropic magnets of the same shape are radially arranged and fixed to a magnetic core metal fixed to a rotating shaft, anisotropic magnets whose anisotropy direction is in the thickness direction are used, An anisotropic magnet rotor characterized in that an even number of four or more magnets are arranged radially at equal intervals, and each magnet is magnetized with three or more odd poles.