JPS5815927B2 - Magnetizing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetizing device for producing a cylindrical magnet having a plurality of poles magnetized in the circumferential direction for use in magnetic bearings, motors, and the like.

In the conventional device of this kind, for example, when polarizing with two inner circumferential poles, as shown in Fig. 1e, a coil 3 is wound around a yoke 2 whose magnetic pole surface is uniformly in contact with the inner diameter of the magnet material 1. It is.

As shown in the figure, the circumferential magnetic flux density distribution on the inner circumferential surface of a cylindrical magnet magnetized by such a device is stronger at the part facing the corner of the magnetic pole, and stronger at the part facing the center of the magnetic pole. 0 part
If it is set to 0, the angle will be low at that 0° portion, resulting in a mountain shape with two peaks on both sides.

In addition, in the case of outer circumferential magnetization, taking two-pole magnetization as an example, a coil 5 is wound around a yoke 4 having a magnetic pole surface whose entire surface contacts the outer circumferential surface of the magnet material 1, as shown in FIG. If a rotated device is used, the magnetic flux density will be high only in the part that is in contact with the end of the magnetic pole face, and the magnetic flux density at the θ° point in the central opposing part of the magnetic pole face will be almost eliminated.

In the above, inner peripheral surface magnetization and outer peripheral surface magnetization have been described for a two-pole magnetizing device, but a similar magnetic flux density distribution state will occur in the case of four-pole, six-pole, or more multi-pole magnetization.

However, when a permanent magnet magnetized in this manner is used in a fixed magnetic field of a motor or a generator, smooth rotational force or smooth generator output cannot be obtained, resulting in poor efficiency.

When used in magnetic bearings, the center of rotation of the rotating shaft could not be stabilized.

In view of the above-mentioned points, the present invention provides a magnetizing device which obtains a cylindrical magnet with multiple circumferential poles magnetized in which the magnetic flux density distribution on the magnetized surface shows a gentle change of one peak. The drawings will be described in detail below.

FIG. 3 shows an embodiment of the present invention in which the inner circumference of a cylindrical magnet material is magnetized, and shows an example of bipolar magnetization.
is a cylindrical magnet material; 12 is a yoke having the same width as the axial length of the cylindrical magnet material 11 and around which a coil 13 is wound; They touch each other, but the distance between them gradually widens on both sides.

The line 13 is shown in cross section, and the direction of the current is shown in the cross section of the line.

When the centerline of the magnet material 11 passing through the contact point with the magnet material 11 at the center of the magnetic pole surface of the yoke 13 is θ°, the magnet material 11 intersects with the center line at each angle up to 90° on both sides. If the shortest distance I between each point on the inner surface of the yoke and the outer peripheral surface of the yoke is set as shown by the solid line in Figure 4a, the magnetic flux density distribution on the inner peripheral surface of the magnetized magnet will be as shown in the solid line in the same figure. The magnetic flux density distribution becomes flat over a wide range.

If the distance g between the magnetic pole face of the yoke 12 and the magnet material 11 is further increased as shown by the dotted line in Figure 4a, the magnetic flux density on the surface of the magnetized magnet will increase as shown by the dotted line in Figure 4a. The distribution becomes a gentle mountain shape, and by choosing the interval g appropriately? It can also be made sinusoidal.

FIG. 5 shows an embodiment of the present invention in which the outer periphery of the cylindrical magnet material 11 is magnetized, and shows an example of bipolar magnetization.

The yoke 14 has an annular portion and a magnetic pole surface of an inner end surface of a leg protruding from the annular portion toward the inner periphery with respect to an outer peripheral surface of the cylindrical magnet material 11 as shown in FIG. Similarly, the magnetic pole surfaces are such that they are in contact with each other at the center in the circumferential direction of the magnet material 11, and the distance between the two is gradually widened toward both sides.

The coil 15 is wound on both sides of the yoke 14 so that the magnetic flux passes in the same direction on the same magnetic pole surface.

When such a magnetic pole surface is magnetized, a magnetic flux density distribution with a flat portion is obtained as shown in FIG.

When the distance from the surface of the magnet material 11 on both sides of the center of the magnetic pole further increases, it becomes a sinusoidal mountain shape.

Although the case of two-pole magnetization has been illustrated above, the same applies to the case of multi-pole of four or more poles.

When a magnetized magnet whose peripheral surface has a sinusoidal or smooth distribution of magnetic flux density in the circumferential direction is used as a magnet to create a fixed magnetic field for a motor or generator, the rotational force of the motor or The output of the generator becomes smooth and efficient.

In addition, as a radial magnetic bearing, as shown in FIGS. 7 and 8, the rotating side magnet 17 fixed to the rotating shaft 16 is magnetized in the radial direction over the entire circumference, with 9 magnetic poles on the outer circumference and the other magnetic pole on the inner circumference. The bearing-side magnet 18 has a pole on the inner periphery of the upper half that attracts the rotating shaft-side magnet 17, and a pole that repels the rotating-side magnet 17 on the inner periphery of the lower half. By using a magnetic bearing having a gentle magnetic flux density distribution of double peaks magnetized by the inventive device, a magnetic bearing with a stable center of rotation of the rotating shaft can be obtained.

As described above, according to the present invention, it is possible to obtain a cylindrical magnet in which one magnetic pole is magnetized in the circumferential direction so that the magnetic flux density distribution is one gentle peak, and such a cylindrical magnet can be used in a motor. Alternatively, if used as a magnet for generating a fixed magnetic field in a generator, the rotational force or generator output can be made smooth and efficient, and if used as a magnet for a magnetic bearing, the stable magnetic field at the center of rotation of the rotating shaft can be generated. Can be made with bearings.

[Brief explanation of the drawing]

Figure 1a is a side view showing a part of a conventional two-pole magnetization device in the circumferential direction of the circumference of a cylindrical magnet, and the same figure is a diagram of the magnetic flux density distribution curve in the circumferential direction of the magnetized magnet. FIG. 2 is a side view showing a part of a conventional circumferential bipolar magnetizing device on the outer periphery of a cylindrical magnet, and FIG. 3 is a side view showing a part of an embodiment of the present invention in cross section. Figure 4a is a diagram showing the spacing between the inner circumference of the magnet material and the yoke at each angle, and the same figure shows the magnetic flux density distribution of a magnet magnetized by a young device using a yoke with the spacing shown in Figure 4a. 5 is a cross-sectional side view of a part of another embodiment of the present invention, FIG. 6 is a magnetic flux density distribution curve diagram of a magnet magnetized by the apparatus shown in FIG. 5, and FIG. A cross-sectional view of a magnetic bearing using magnets magnetized by the inventive device No. 8 is a cross-sectional view taken along the line AA in FIG. 7. 11... Cylindrical magnet material, 12.14... Yoke, 15.
13...Coil.

Claims (1)

[Claims] 1. In a magnetizing device, each magnetic pole surface of a coil-wound yoke is opposed to the circumferential surface of a cylindrical magnetic material so that multiple poles are formed in the circumferential direction of the circumferential surface, and the magnetic material is magnetized. The center part of each magnetic pole surface of the yoke in the circumferential direction of the magnet material is in contact with the circumferential surface of the magnet material, and the distance from the circumferential surface of the magnet material is gradually widened on both sides of the center part. A device featuring: