JPS63240007A - Magnetization of permanent magnet - Google Patents

Abstract

PURPOSE:To increase the total magnetic flux of a magnet and to contrive improvement in preciseness of the angle of magnetization by a method wherein the unmagnetized zone of the magnet once magnetized is moved to the part which can be magnetized. CONSTITUTION:The unmagnetized zone 1 generating in the permanent magnet 5, on which multipole magnetization is conducted, is magnetized twice by moving the magnet or by using another magnetization yoke, and the permanent magnet having no unmagnetized zone is manufactured. To be more precise, the second magnetizing operation is performed on the magnetized magnet by rotating it about one half of the angle of magnetization from the condition A to the condition B, for example, and the magnetization having no unmagnetized zone 1 as the condition C is made possible. By effectively using the unmagnetized zone 1 of the permanent magnet 5, the total quantity of magnetic flux can be increased, and the improvement in accuracy of magnetization angle can also be achieved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a motor? This relates to permanent magnets with multipolar magnetization used in sensors, etc.

[Summary of the invention]

The present invention is designed to move the magnet through the non-N magnetized zone 1 of the person shown in FIG. 1, which occurs in a multi-pole magnetized permanent magnet as shown in FIG. By magnetizing, it is possible to manufacture a permanent magnet having no non-N magnetized zone as shown in FIG. 1B.

[Conventional technology]

Conventionally, permanent magnet magnetization can be divided into unidirectional magnetization and multipolar magnetization. A simple magnetization in the NS direction as shown in FIG. 2 is called unidirectional magnetization, and a magnetization in which there are two or more sets of Is in the same magnet as shown in FIG. 1 is called multipolar magnetization.

A typical magnetizing yoke used for multi-pole magnetization has a cross-sectional view as shown in FIG. Among these, 3 is an iron part, 4 is a coil, and 5 is a permanent magnet. The magnetization pattern of the permanent magnet magnetized by this magnetization yoke is as shown in Figure 1, and a very weakly magnetized portion called an unmagnetized zone occurs. This is the part of coil 4 in the magnetizing yoke in Figure 3. Most of the magnetic flux generated by energizing the coil passes through the iron part 3, generating enough magnetic flux to fully magnetize the coil 40 part. This is due to not doing so.

[Problem that the invention seeks to solve]

In the conventional method using only Figure 1, the volume of the non-hazardous sheath 71 hardly contributes to the total magnetic flux generated by the permanent magnet, and therefore, when used in a motor, etc., it causes a lack of torque. Also, when this magnet is used for a sensor etc., as shown in Fig. 4, by rotating the permanent magnet 5,
When the magnetic flux density is detected by the Hall element 6, a waveform similar to that shown in Figure 5 is obtained, and the magnetization angle 7 is large due to the unmagnetized zone 1.The object of the present invention is to detect the unmagnetized zone j. Magnetizes by magnetizing twice, increases the total magnetic flux of the magnet, and M
The purpose of the present invention is to improve the accuracy of the magnetic angle. [Means for solving the problem] In order to solve this problem, the present invention uses a magnet magnetized as shown in Figure 1 for a person to be magnetized as shown in Figure 6. By rotating the state by about half the magnetization angle as shown in FIG. 6B and performing magnetization for the second time, an unmagnetized sea 71 as shown in FIG. 6C is obtained.
This enables magnetization without

〔Example〕

(Example 1) FIG. 1 shows a magnet having an anisotropy in the radial direction with an outer diameter of 28+ m, an inner diameter of 25 m, and a height of 7 m, and is magnetized with 8 poles on the outer periphery. The material is a rare earth plastic magnet of the MT-0OTY system, and is used in the rotor magnet of a DC motor. At that time, a Hall element is set inside the motor, and a mechanism is used to detect the rotation angle as shown in Figure 4. If this magnet is magnetized using the conventional method using the magnetizing yoke shown in FIG. The conventional product shown in Figure At B fC is rotated by 22.5 degrees Celsius and magnetized for the second time. Table 1 shows an index comparison of magnetic flux amount and magnetization angle accuracy.

In this way, the present invention has made it possible to achieve very high quality magnetization, making it possible to create a high-precision motor, thereby contributing to technological improvements in the motor industry.

(Example 2) The magnet shown in FIG. 7 is a sensor magnet of φ32×φ26X2+a+, and the rotation is detected by a Hall element separated by about 1111I. According to the present invention, this magnet is also magnetized in one direction as shown in Fig. 8 for the -th magnetization, and in the second magnetization as shown in Fig. 7, which is the conventional method of magnetization. By using the yoke, as shown in FIG. 8B, the unmagnetized sea 7
A highly accurate permanent magnet with no 1 was obtained.

〔Effect of the invention〕

As described above, according to the present invention, by effectively utilizing the unmagnetized zone of the permanent magnet, it is possible to increase the total amount of magnetic flux and improve the accuracy of the magnetization angle.

The present invention relates to a magnetization method, and is effective for all types of magnets, such as rare earth sintered magnets, ferrite magnets, alnico magnets, etc., regardless of the magnet material used.

[Brief explanation of the drawing]

Figure 1 is a sketch of a conventional multi-pole magnetized magnet, with 1 showing the unmagnetized zone and 2 the magnetized zone. FIG. 1B is a sketch of a multi-pole magnetized three-direction magnet according to the present invention. FIG. 2 is a sketch of a conventional unidirectionally magnetized product. Fig. 3 is a cross-sectional view of a multi-pole N magnetic yoke, 3 is an iron part, 4 is a copper coil, and 5 is a permanent magnet. FIG. 4 is an explanatory diagram in which the magnetization angle of a conventional multi-pole magnetized permanent magnet is detected by a Hall element. FIG. 5 is a waveform diagram when magnetic flux density was measured by the method shown in FIG. 4, A is a product using the conventional method, B is a product according to the present invention, and 7 is a magnetization angle. Figure 6 is a detailed explanatory diagram of the present invention.
B is the position where the magnet is rotated 22.5° and magnetized for the second time, and C is the magnet after it has been magnetized twice. Figure 7 is a sketch of a conventional sensor magnet. FIG. 8 is an explanatory diagram of the present invention. Person 0 is a magnet whose first magnetization was unidirectionally magnetized, and B is a magnet whose second magnetization was performed using a multipolar magnetizing yoke. Applicant Seiko Epson Co., Ltd. Representative Patent Attorney Mogami (1 other person)

Claims (1)

[Claims] In the multi-pole magnetization method for permanent magnets, in order to eliminate unmagnetized zones, the unmagnetized zone part of the once magnetized magnet is moved to a magnetizable part, or a separate magnetization yoke is used. A method of magnetizing a permanent magnet, which is characterized by performing magnetization twice.