JPS6058565B2 - Magnetization method of asymmetric multipolar magnet disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of magnetizing an asymmetric multipolar magnet disk for generating an asymmetric multipolar magnetic field.

A multipolar magnet disk is often used to detect rotation angle, rotation speed, etc., but the strength of the magnetic poles magnetized on the multipolar magnet disk is usually the same. . Therefore, in such a multipolar magnetic disk, the first
As shown in the figure, an alternating symmetrical magnetic field is generated with rotation. By the way, depending on the application, it may be required to generate an alternating asymmetrical magnetic field with rotation as shown in Figure 2, and for this purpose, the surface magnetic flux density of the magnetic poles may be increased or decreased depending on the position. I have to make small changes. Therefore, the usual method of magnetizing a multipolar magnet disk cannot be used as is. In view of the above-mentioned points, the present invention provides a method for magnetizing an asymmetric multipolar magnet disk, which allows magnetic poles to be made stronger or weaker depending on the position by magnetizing operations in one circle. DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the method of magnetizing an asymmetric multipolar magnet disk according to the present invention will be described below with reference to the drawings.

In FIG. 3, the magnetizing yoke 1 has a cylindrical shape, and pole portions 2A to 2F are formed at equal intervals on the inner peripheral surface. Further, deep slots 3 are formed on both sides of the pole parts 2A, 2C, and 2E, and shallow slots 4 are formed on both sides of the pole parts 2B, 2D, and 2F. The slots 3 and 4 on both sides of each of the pole parts 2A to 2F accommodate respective windings 5A to 5F, and the windings are connected in series in sequence. Here, windings 5A, 5C,
The winding directions of 5E and windings 5B, 5D, and 5F are opposite to each other. The magnetic disk 6 before magnetization is installed in the magnetization yoke 1 as described above, and the DC power source 7 is drawn out with the windings with the pole parts 2A to 2F facing the circumferential surface of the magnetic disk 6. End 8A,
8B, a current of about several hundred amperes instantaneously flows through each winding 5A to 5F, and magnetization is executed.

At this time, since the windings 5A to 5F are connected in series, the current flowing through each winding is the same, but the depth of the slot, that is, the position in the depth direction of the winding, differs depending on the pole. , a strong magnetic field is generated in the pole parts 2B, 2D, and 2F where the winding position is shallow, and the pole parts 2A, 2C, and 2E where the winding position is deep.
A relatively weak magnetic field in the opposite direction is generated. This is because the deeper the winding position, the longer the pole portion becomes, and the loss at the pole portion increases. Therefore, the pole parts 2B, 2D, 2F
A strong magnetic pole is formed on the circumferential surface portion of the magnetic disk 6 facing the pole portions 2A, 2C, and 2E, and a relatively weak magnetic pole of opposite polarity is formed on the circumferential surface portion of the magnetic disk 6 facing the pole portions 2A, 2C, and 2E. Thus, an asymmetric multipolar magnet disk is completed. According to the above embodiment, by changing the depth of the winding provided at each pole,
A strong magnetic pole and a weak magnetic pole can be simultaneously formed on the circumferential surface of a magnetic disk in one magnetization operation.

It goes without saying that the number of pole parts of the magnetizing yoke can be increased or decreased as appropriate.

As described above, according to the method of magnetizing an asymmetric multipolar magnet disk of the present invention, it is possible to make the magnetic poles stronger or weaker depending on the position by a single magnetization operation.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of an alternating symmetric magnetic field, FIG. 2 is an explanatory diagram showing an example of an alternating asymmetric magnetic field, and FIG. 3 is an implementation of the method for magnetizing an asymmetric multipolar magnet disk according to the present invention. It is a sectional view showing an example. 1... Magnetizing yoke, 2A to 2F...
・Pole part, 3, 4...Slot, 5A to 5F・
... Winding wire, 6 ... Magnetic disk, 7 ...
...DC power supply.

Claims (1)

[Claims] 1. Windings with different depths are provided around the plurality of pole parts formed on the inner circumferential surface of the magnetizing yoke according to the position of each pole part, and the windings are connected in series, and the windings are connected in series to the pole parts. 1. A method of magnetizing an asymmetric multipolar magnet disk, characterized in that a DC current is passed through the windings in a state in which the magnetic disks are arranged so that their circumferential surfaces face each other.