JPS5874018A - Magnetization distribution control for cylindrical rare-earth cobalt magnet - Google Patents

Abstract

PURPOSE:To provide any required magnetization distribution pattern easily, by a method wherein a magnetic material that has satulating magnetic flux density required for the magnetization distribution is used for a core. CONSTITUTION:A lower punch 4 is fixed into a mortar 1, and material powder 8 is put into a through-hole 2 in which an inner rod 5 is projected. Then, an upper punch 3 is inserted in the mortar 1 up to 2-4mm., turning on electricity for a coil 6 to form a magnetic field. After this, the upper punch 3 is moved downward, while the lower punch 4 is moved upward to press the magnetic powder 8, which a cylinder magnet is formed. At this time, by changing the magnetic characteristics of the core 5, the magnetization distribution of the cylinder magnet in the diameter direction can be controlld. The magnetic characteristics can be changed according to the required magnetization distribution by selecting a material among the ones having various satulating magnetic flux density. Thus, any required pattern of the magnetization distribution can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a rare earth material having a cylindrical shape and anisotropy in the diametrical direction,
This invention relates to a method for controlling magnetization distribution of cobalt permanent magnets. Rare earth magnets have superior magnetic properties compared to conventional ferrite and alnico magnets.Currently, there are two manufacturing methods: powder sintering type and powder bonding type (pound magnet). Not only magnets whose main component is ROO@ compound (where R is a combination of one or more rare earth elements) but also Oe (0oOuFe)@, S
m2 (Co0uPeZr)By.

(8m(38)H(n Onu lFeZr)tts
8ml (0o()ulPeHf)ly thread system nu
Additive precipitation hardening magnets are widely used in practice. Among them, powdered sintered rare earth cobalt magnets have high performance and are very useful, but they also have many defects that arise from the manufacturing process. In particular, the table 1f1t is made into powder, molded in a magnetic field, and 1100 ~
Sintered at 1200℃, composition L = 90t)℃~400℃
C. aging treatment is applied, so a single cylindrical magnet has the disadvantage that one crack occurs when anisotropy is imparted in the diametrical direction due to thermal strain and the difference in shrinkage rate of crystals due to orientation. In addition, suitable orientation (magnetization direction) is now available in various shapes depending on the application.
However, it is not easy to control the orientation by modifying the shape. In particular, in radial cylindrical magnets, not only the magnetization direction but also the magnetization distribution is controlled. The present invention is to control the magnetization distribution of a rare earth cobalt magnet, which eliminates the above drawbacks and makes it possible to easily obtain a desired magnetization distribution when forming a cylindrical rare earth cobalt magnet whose magnetization direction is in the radial direction of the grindstone in a magnetic field. The present invention provides a method.

In the present invention, the rare earth cobalt magnet is a resin bonded type magnet,
Or they are made with metal bonded magnets. In other words, rare earth cobalt alloy ingots are crushed as they are for ROO5 series, and R1COH compounds are subjected to solution treatment and aging treatment, then coarsely crushed, and then finely crushed to a particle size of 2μ to 60μ, and then resin is added and cross-wired to generate a magnetic field. The aim is to freely control the magnetization distribution in the radial direction by medium compression molding.

Therefore, it is produced by pressing, heating and solidifying from a direction perpendicular to the radial direction (direction of application of the a-field).

In the present invention, molding in a magnetic field is performed using the L mold shown in FIG.
This is done using a duck generator tube.

Figure IN1 shows the magnetic forming apparatus 1'□ used for carrying out the present invention.
:111 and a vertical cross-sectional view of the mold. An upper bunch 5 is disposed at the center of the die 1 so as to be vertically movable so as to fit upwardly into the cylindrical through hole 2, and a lower bunch 4 is disposed at the center of the die 1 to fit into the cylindrical through hole 2 from below. A central shaft rod 5 is provided at the center of the shaft. 5
can be moved up and down freely. A yaw 77 and a coil 6 are arranged on the side of the mill 1 to generate a parallel magnetic field between lateral forces.

Molding molds 1, 5, and 4.5 are made of non-magnetic material, Sue, Bs
.

It is made from stellite etc. The magnetic properties of core 5 are
Various saturation magnetic flux densities (Be
)'e You can choose from four materials. For example, B8=O, (non-magnetic material) B8=≦4 (weakly magnetic material) or #iBs≧7KG (
ferromagnetic material) is selected.

In the case of Fig. 1, insert the lower bunch 4 into the mortar 1 and insert the middle rod 5.
Insert the material powder (in this case, a mixture of rare earth cobalt powder and resin) into the through hole 2 with the upper punch 5 protruding, and fit the upper punch 5 into the white part of 2 by 2 to 4%. DC current is applied to the coil, a magnetic field is applied through the yoke 7, and the magnetic powder 811 is pressed and molded while moving the upper punch 5 downward and the I punch 4 upward. A cylindrical magnet of the perspective view shown in the figure is obtained. The present inventor has discovered that by changing the magnetic properties of the core 5, the magnetization distribution of the magnetized radial cylindrical magnet can be controlled. Hereinafter, the method for controlling the magnetization distribution of a resin-bonded rare earth cobalt cylindrical magnet according to the present invention will be described in detail using Examples.

Example 1 8m (Co, 746 t3uα08 Ire (L22
Zr1026) alloy with a5 composition, gold f: It was melted using a high frequency melting furnace and cast into a mold. The alloy ingots were filled with columnar crystals. Next, the alloy ingot is
Solution treatment was performed at 1170° C. for 5 hours in a gas atmosphere furnace, and cooling was performed using Ar gas. Next, 800℃ x 2 hours + 720℃
Aging treatment was performed at ℃ for 4 hours to perform magnetic hardening.

The ingot, which is in the form of an alloy block and has been subjected to the necessary heat treatment, is coarsely pulverized using a Huffmark 2 shear, and then finely pulverized using a jet mill to a particle size of 1 μm to 40 μm. 98 parts by weight of the fine powder thus obtained and the liquid epoxy resin Type 2 were kneaded and subjected to pressure molding in a magnetic field using a magnetic field molding apparatus as shown in FIG.

The shape of the obtained cylindrical magnet is as shown in the perspective view of FIG. 2, and is a thin book with dimensions of φ10×φ5×5h%. Figure 5 shows the material of the core 5: t-(A)-Stellite (non-magnetic)
(B)-Magnetic carbide (Be4KG) (0)-8
When the U roller (Bs13KG) was used, the behavior of the magnetic powder in the mold 8, that is, the magnetic field distribution of the applied magnetism @15KOe was shown. The cylindrical magnet thus obtained was mounted in a shield case made of pure iron, and the magnetization waveform of the gap (empty 1!ll) between the magnet and the case was measured, and the results are shown in the fourth bubble.

jill 4 @ (A) is a 9 o'clock magnetization waveform of a cylindrical magnet made using a non-conductive core, and has a sine waveform with a sharp peak. The peak value was 5200G when measured by a gas meter. Similarly (B) uses magnetic carbide for the core, but it has a slightly trapezoidal sine curve with a peak value of 480LIG, which is dangerous. (
O) In the example using 13U, T, f for the core, it has a trapezoidal sine curve and the peak value is a little low at 4500G, but
The magnetic field area has been expanded considerably.

In this manner, the resin-bonded magnet can easily provide a cylindrical magnet having an orienting magnetic field with the magnetic field distribution arbitrarily controlled. In this example, we have described the trapping of a M-based compound in R300, but it is of course possible to obtain all four different effects with other compositions.

Comparative Example t smooth Fig. 1 Magnetic field forming device T-1 A cylindrical magnet having the same shape as in Example 1 was made. The fur is made of magnetic carbide (Bs4KG) and heated at 1150°C x 1. Sintered between #I#. Outside of sintering! In the case of the one shown in Fig. 5 of Fig. 5, the most common cases were those that caused one beat and two cracks of 9 and deformation. This is an unavoidable defect because the shrinkage rates in the anisotropic direction and the perpendicular direction are different.

As detailed above, according to the present invention, when a radial cylindrical resin-bonded rare earth cobalt magnet is subjected to magnetic field forming, the magnetization distribution of the magnet can be easily changed. IJ II, and the desired magnetization distribution can be easily achieved.

The method of the present invention is particularly effective for making small micro motors, coreless motors, and stepper motors J41 and reducing power consumption, and has many other industrial applications such as magnetic sensors and rotating needles.

[Brief explanation of the drawing]

Figure IIi shows the cross section of the mold of the magnetic field forming apparatus used in the method of the present invention.
6... Coil 7... Iron yoke 8... Magnetic powder Figure 2 is a perspective view of a cylindrical magnet. Figure 3 (A) # (B) # (0) shows magnetization of resin-bonded rare earth cobalt powder. A plan view showing the distribution, a magnetization waveform diagram showing changes in the gap magnetic flux in the s BmCO, and Fig. 5 a perspective view of a s BmCO@ sintered cylindrical magnet made in a comparative example, and 9 shows cracks after sintering. shows. Above Figure 1 Figure 2 Figure 5

Claims (1)

[Claims] A gold INK with a top punch and a bottom punch that fit into the mill, and a core that slides inside the bottom punch.
1. When manufacturing a cylindrical permanent magnet by molding rare earth magnetic powder in a magnetic field while a magnetic field is applied, the core has a saturation magnetic flux density (hereinafter referred to as Be) of 4.
A method for controlling the magnetization distribution of a cylindrical rare earth cobalt magnet, comprising controlling the magnetization distribution of the magnet using a magnetic material of KG or more.