JPS6284898A - Manufacture of two-pole magnet in diameter direction - Google Patents

Abstract

PURPOSE:To make a magnet middle in size, and to improve the characteristic of a motor by using a magnetic material provided with a desired saturation magnetic characteristic, for a center core of a metallic die, and also executing a press by giving a vertical magnetic field to a die shaft. CONSTITUTION:An upper punch 3 and a lower punch 4 are provided, and also a center core 5 is provided in the center of a cylindrical die 1. A magnet is manufactured by executing a press by giving vertically a magnetic field to a die shaft by an electromagnet 6 against a magnetic powder 2 which has been packed in the inside of the die 1. In this case, a magnetic material having a desired saturation magnetic characteristic is used for the center core 5 and against the outside peripheral surface of the magnet, an anisotropic direction can be controlled by a magnitude of a saturation magnetization of the center core 5. Also, as the saturation magnetization becomes large, a total magnetic flux quantity can be enlarged. According to this method, the magnet can be made small in size, and also the characteristic of a motor can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a cylindrical magnet having magnetic poles in the radial direction.

[Prior art]

The magnet having the above structure is manufactured by a manufacturing apparatus as shown in FIG. A conventional device of this type has a cylindrical die 1 made of a non-magnetic material. Upper punch 3. Lower punch 4. It consists of a core 5 of non-magnetic material, and an electromagnet 6, and a magnetic field is applied by the electromagnet 6 to the magnetic powder 2 filled in the die 1 in a direction perpendicular to the axis of the die 1, and press molding is performed. The press molded body magnetized in the radial direction in this way is fired, and the second
A cylindrical radially bipolar magnet 7 having magnetic poles in the radial direction as shown in the figure is obtained. As will be understood from the following description, if the material of the core 5 is changed, the apparatus shown in FIG. 1 becomes a manufacturing apparatus for carrying out the manufacturing method according to the present invention.

[Problems to be solved by the invention]

The magnets obtained as described above have parallel magnetization directions, and have a sinusoidal peripheral magnetic flux distribution as shown in FIG. However, in a cylindrical magnet with radial magnetization made using this conventional manufacturing method, the magnetization distribution can only be as shown in Figure 3, and it is impossible to manufacture magnets with other Ω-shaped magnetization distributions. could not.

The object of the invention is therefore to find a method for producing a magnet with a magnetization distribution different from that shown in FIG. More specifically, the present invention aims to provide a method for manufacturing a cylindrical magnet with radial magnetization in which a part of the outer circumferential magnetic flux distribution is perpendicular to the outer circumference.

[Means for solving problems]

According to the present invention, a die of a mold, an upper punch and a lower punch that slide on the inner surface of the die, and a core located at the center inside the die are used to control the magnetic powder filled inside the die. In contrast, in a method of manufacturing a magnet by applying a magnetic field perpendicular to the axis of the die and pressing.

A magnetic field perpendicular to the axis of the die is applied to the center core of the mold using a magnetic material having desired saturation magnetization characteristics.

Thereby, a method for manufacturing a radial dipole magnet is obtained, which is characterized by obtaining a magnet having a controlled magnetization distribution.

According to this manufacturing method, if a material with low saturation magnetization is used for the core, the magnetic flux distribution will be partially perpendicular to the outer circumferential surface of the magnet, and as the saturation magnetization of the core is increased, the part that is perpendicular to it will be distributed vertically. The area of will increase.

Therefore, depending on the magnitude of saturation magnetization of the center core of the mold.

One cylindrical magnet with different magnetic flux distribution is obtained.

〔Example〕

The present invention will be explained in detail by way of examples.

Referring to FIG. 1, the core 5 is made of a magnetic material.

And the saturation magnetization of the material is 4 kG, 6.5 kG
.

A 10 kG one was used. When a magnetic material is used as the core 5, the magnetic flux distribution of the magnetic powder 2 inside the die 1 is as follows.

Since the core 5 is a magnetic material, it concentrates on the core 5. The degree of concentration is 4 kG (
6.5 kG (10 kG. With this, the magnetic flux distribution of the cylindrical radial bipolar magnet obtained by firing the press molded body after magnetic field press molding is determined by inserting the magnet 9 into the magnetic yoke 8 shown in Fig. 4. Measured at Broso 1o.

Figures 5, 6, and 7 show the results of this measurement.
The figure shows the case of 6.5 kG, and Fig. 7 shows the case of 10 kG.

FIG. 8 is a diagram showing the magnetization distribution in the cross section of the sample, in which (a) shows the one corresponding to FIG. 5, and (b) shows the one corresponding to FIG. 7. The part corresponding to Fig. 6 is omitted because it is between (,) and (b). Note that the magnetization distribution of the conventional sample is uniformly parallel, as shown in the front of FIG.

From the above, as the core saturation magnetization increases, the area of the part magnetized in the magnetic flux direction substantially perpendicular to the outer peripheral surface near the magnetic pole of the magnet is obtained, and the size of the area and the magnet's The total amount of magnetic flux is 4 kG (6,5 kG (1
It turns out that it is 0kG.

Table 1 shows the characteristics in Figures 5, 6, and 7 for an outer diameter of 11 m.
, a cylindrical rare earth permanent magnet with an inner diameter of 5.5 terms and a length of 15 terms. From Table 1.

The total amount of magnetic flux is OkG < 4 kG < 6.5
kG <10kG Tea Arca, magnetic flux amount by Tuber bar/4 coils for coreless motor is OkG (10kG
<6.5 kG (4kG), and by using a magnetic flux distribution that matches the magnetic flux area of the coil used in the motor, the two-motor characteristics have been significantly improved compared to conventional products.

Table 1 〔Effect of the invention〕 As explained above, according to the present invention, anisotropy can be achieved.

Magnets manufactured by the manufacturing method of the present invention can be assembled into coreless motors, etc., and by selecting a magnetization distribution that matches the motor coil, they can consume less power than conventional magnets, making them suitable for use in higher-efficiency motors. Ideal for In addition, it can be made smaller than conventional magnets, and the miniaturization makes it possible to provide a cheaper magnet, which has a great effect on industrial use.

[Brief Description of the Drawings] Fig. 1 is a longitudinal sectional view of a magnet manufacturing apparatus that can be used in both the manufacturing method according to the present invention and the conventional manufacturing method, and Fig. 2 explains the magnetization direction of the conventional magnet. Figure 3 is a diagram of the outer circumferential magnetic flux distribution of a conventional magnet. FIG. 4 shows a method for measuring the distribution of magnetic flux around the outer circumference of a magnet. FIGS. It is a figure for explaining the magnetization direction of the magnet of a figure. Explanation of symbols: 1 is cylindrical gooey, 2 is magnetic powder. 3 is the upper E inch, 4 is the lower/J inch, 5 is the center core, 6 is the electromagnet, 7 is the cylindrical radial bipolar magnet, 8 is the magnetic yoke, 9
1 is a magnet, and 10 is a probe. Figure 9 Figure 1 Figure 2 Hannau-Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] (1) Using a die of a mold, an upper punch and a lower punch that slide on the inner surface of this die, and a core located in the center of the die, the magnetic powder filled inside the die is applied to the die. In a method of manufacturing a magnet by applying a magnetic field perpendicular to the axis and pressing, a magnetic material having a desired saturation magnetization characteristic is used in the center of the die to apply a magnetic field perpendicular to the axis of the die, thereby controlling the A method for producing a radial dipole magnet, characterized by obtaining a magnet having a magnetization distribution.