JPS62232910A - Manufacture of multi-polar anisotropic resinous magnet - Google Patents

Abstract

PURPOSE:To obtain an anisotropic resinous magnet superior in performance, by performing orientation twice and then performing cooling and solidification so that multi-polar anisotropic orientation is made to a deep part of the resinous magnet. CONSTITUTION:When a d-c current is supplied into a radial anisotropic orientating coil 7, the magnetic flux generated passes through the N pole 1 of the radial anisotropic orientating magnetic poles and the inside of the molds 3, serving as flow 5 of the radial anisotropic orientating magnetic flux and flowing to the S pole 2 of the radial anisotropic orientating magnetic poles to form a closed loop. Then, a pulsed current C is supplied to a pulsed magnetic field- generating coil 9 to generate a multi-polar anisotropic orientating magnetic field 10 in the cavity. Some of magnetic powder orientated so far in the radial direction, on which the magnetic field 10 has a strong effect, are turned to the opposite direction to obtain multi-polar anisotropic orientation, and the radial anisotropic orientation is left still on the part, on which the magnetic field 10 has a weak effect. Hence, the anisotropic resinous magnet superior in performance is obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for manufacturing an anisotropic resin magnet, and in particular to an anisotropic resin magnet that allows easy multipolar anisotropic orientation deep into the anisotropic resin magnet. Concerning a method for manufacturing resin magnets.

[Conventional technology]

Conventionally, multipolar anisotropically oriented resin magnets have been produced by a method of multipolar magnetizing an isotropic resin molded product made by kneading magnetic powder and polymeric material and molding without orienting the magnetic powder, or by a method of multipolar magnetization during molding. N,
Most of them were created by a method of multipolar magnetization of an anisotropic resin molded product in which magnetic powder was oriented radially or axially anisotropically by the magnetic field of the S2 pole. In consideration of ease of magnetization, it is preferable that the resin molded product be radially or axially anisotropically oriented in advance as in the latter case.

In order to obtain the above radial or axial anisotropic resin molded product, N, SZM+
The resin may be molded in a space (cavity) in which the two faces face each other. This method has the advantage that it is possible to apply a sufficient orienting magnetic field to the cavity of the molded product, resulting in a degree of orientation of over 95%.Furthermore, it contains magnetic powder to improve magnetic properties. Even if the amount is increased and the flow orientation is poor, it is possible to mold and orient the material deep inside.

(Problem to be Solved by the Invention) However, when magnetizing a radially or axially anisotropically oriented molded product into multiple poles, the magnetic path 6 used for magnetization (6 in Figure 2-2) ) is the axis of easy magnetization of the magnetic powder (the direction in which the magnetic powder is easily magnetized) and 9
Because it faces in the 0° direction, the degree of orientation itself is high, but since the orientation direction is one part, the magnetism is restricted in that part, and the magnetic performance or the performance of the material is quite low. There was a major theoretical problem in that it had to be used in

As a method to solve the above problems, a method has recently been used in which magnetization is applied to a resin molded product that has been previously oriented with multipolar anisotropy in a shape similar to the magnetic circuit used for magnetization. There is. In this method, for example, as shown in the cross-sectional view of FIG. 3-1, a molded product is created in a cavity in which N and S poles are alternately applied.

Although the resin molded product obtained by this method has an alignment direction that matches the magnetic circuit used for magnetization, it does not have an N-S pole structure or opposing magnetic poles to generate a multi-pole alignment magnetic field. Compared to the gear-to-gear permeance used in the radial anisotropic orientation and axial anisotropic orientation described above, this method requires orientation using a magnetic field generated only by leakage permeance. The magnetic field is opposed magnetic poles (radial anisotropic orientation, aki.

There is a fundamental drawback that the amount is a few to several tenths of that of the chassis anisotropic orientation. In addition, the depth of the orientation itself is such that magnetic flux hardly passes in the radial direction or thickness direction of the molded product like with opposing magnetic poles, so the more poles there are, the more magnetic flux passes only through the surface layer, Orientation no longer occurs, and most other areas remain isotropic, and most of the areas do not contribute to improving magnetic properties. Furthermore, in the case of multiple poles, the distance between the N and S magnetic poles becomes close, so the magnetic flux does not pass through the cavity and leaks directly between the magnetic poles, resulting in a synergistic effect with a decrease in the alignment magnetic field itself, resulting in a significant decrease in efficiency. I had left it behind.

In addition, for this reason, high-performance materials with a high content of magnetic powder, which could be used without problems in radial anisotropic orientation and axial anisotropic orientation, have poor flow orientation, so they are rarely used in multipolar molding orientation. It had a major fundamental defect in that it could not be used because it could not be oriented.

In this way, even if a multipolar anisotropic orientation molding method is used, only materials with a small magnetic powder content and low magnetic properties can be used. In the end, the results were not much different from those in which a large amount of high-performance material was oriented.

(Object of the invention) The present invention has been made in view of the above-mentioned conventional problems,
The purpose is to develop a method for manufacturing resin magnets that have multipolar anisotropically oriented parts that can fully demonstrate magnetic performance, especially for resin magnets that have multipolar anisotropically oriented parts not only in the surface layer but also deep inside. The purpose is to provide a manufacturing method.

Means for Solving Problem C] The above-mentioned object of the present invention is to maintain the resin magnet composition containing magnetic powder in a molten state in a cylindrical cavity and to apply a magnetic field to the cavity. A method for producing a multipolar anisotropic orientation magnetic field including a step of anisotropically orienting powder, the step of anisotropically orienting the powder comprising applying radial or axial anisotropic orientation exit from the inner and outer peripheral sides of the cavity. A multi-pole method including the step of radially or axially anisotropically orienting the magnetic powder, and the step of applying a multipolar anisotropic orienting magnetic field from the outer periphery of the cavity to orient a part of the magnetic powder in a multipolar anisotropic manner. This is achieved by a method of producing a polar anisotropic orienting magnetic field.

Regarding the manufacturing method of the multipolar anisotropic orienting magnetic field of the present invention, Part 1-
This will be explained using FIGS. 1 to 1-4.

1-11 to 1-3 are schematic diagrams showing the relationship between the molded product in the mold cavity and the distribution magnetic poles, respectively.

In Figures 1-1 to 1-3, 1 is an N pole for radial anisotropic orientation, 2 is an S pole for radial anisotropic orientation, 3 is a molded product (or cavity), and 4 is a ferrite. magnetic powder,
5 is a flow of magnetic flux for radial anisotropic orientation, 7 is a radial anisotropic orientation magnetic field generating coil, 8 is a demagnetizing coil, 9 is a pulse for multipolar anisotropic orientation that alternately applies N and S poles. It is a coil for a magnetic field, and IO is a magnetic field for multipolar anisotropic orientation.

In Fig. 1-4, a is a graph representing a current waveform for radial anisotropic orientation, b is a graph representing a current waveform for high frequency attenuation demagnetization, and C is a current waveform for multipolar anisotropic orientation using a pulsed magnetic field. This is a graph representing

As one aspect of the method for manufacturing the multipolar anisotropic resin M1 stone of the present invention, first, the N pole 1 for radial anisotropic distribution, the radial In the space (cavity) between the S poles 2 for anisotropic force distribution, the mixture of magnetic powder and polymer material is brought into a molten state so that the magnetic powder can easily change direction. Then, a direct current having a waveform shown in a of FIG. 1-4 is passed through the radial anisotropic orientation coil 7. The magnetic flux generated by this coil passes through the radial anisotropy orientation magnetic pole N pole 1, passes through the inside of the molded product 3, and becomes a radial anisotropy orientation magnetic flux flow 5 as shown in Figure 1-2. It flows to the magnetic pole S pole 2 for anisotropic orientation, forming a closed loop.

At this time, magnetic powder (for example, ferrite magnetic powder) is arranged in the radial direction inside the molded product as shown in FIGS. 1-2. The order in which the resin magnet material is made to exist in a molten state in the cavity and the current is passed through the coil is not limited to the above. In this case, the injection and orientation steps are completed in about 0.5 seconds to 1 second, depending on the material and magnetic field conditions.

Next, turn off the current for radial anisotropy orientation and
A demagnetizing current with a waveform shown in is applied. This demagnetizing current is
Use a current with as high a frequency response as possible to avoid changing the orientation of the ferrite magnetic powder. For example, compared to a radial orientation coil, a demagnetizing coil can be used by reducing the number of turns to lower the coil inductance and applying a reverse pulsed magnetic field with a short pulse width.
It can be demagnetized in 000 to 1710000 seconds.

Next, a pulse or current C having the waveform shown in Fig. 1-4 is passed through the cavity to the pulsed magnetic field generating coil 9 shown in Fig. 1-3, thereby generating a magnetic field of 1° for multipolar anisotropic orientation. .

As a result, among the magnetic powders that have been oriented in two radial directions up until now, those in the areas where the magnetic field 10 for multipolar anisotropy orientation is strongly applied change their orientation as shown in FIG. The magnetic field 10 for multipolar anisotropy orientation is weak, and the radial anisotropy orientation remains.

After being oriented twice in the manner described above, an anisotropically oriented resin magnet having a multipolar anisotropically oriented portion is obtained by cooling and solidifying.

The method of generating a magnetic field for demagnetization is not limited to the method described above, but it is also possible to apply a magnetic field with a short pulse width of about 1,710,000 seconds to the pulsed magnetic field generating coil 9 to demagnetize only the necessary portion, and then perform orientation. wide pulse width l7100~
It is also possible to apply a pulse magnetic field for about l/I 000 seconds.

In addition, as a method for making the polymer material mixed with magnetic powder in a molten state exist in the cavity, injection molding, transfer, hot pressing, reaction molding, etc. can be used.

The anisotropic resin magnet composition manufactured by the anisotropic resin magnet manufacturing method of the present invention contains magnetic powder and a binder as main components, and a lubricant and the like are also added.

As the magnetic powder, ferrite, rare earth metal such as samarium cobalt, etc. can be used, but ferrite is preferably used because it requires less energy for magnetization.

Specific examples of ferrites used include strontium ferrite and barium ferrite.

As the binder, any conventionally known binder material for resin magnets such as polyamide, polybutylene terephthalate, polyphenylene sulfide, etc. can be used. The blending ratio of the magnetic powder is in the range of approximately 70wL''* to 90wt!ji with respect to the weight of the resin magnet composition.

As the lubricant, metal stearate, bisamide, etc. are used, and as the surface treatment agent, silane, titanate, etc. are used.

In the method for manufacturing an anisotropic resin magnet of the present invention, since the magnetic field for multipolar anisotropic orientation is applied after radial or axial anisotropic orientation, the magnetic field for multipolar anisotropic orientation is applied deep into the molded product. is induced.

This is because the multipolar anisotropic orientation magnetic field creates a magnetic chain with the radially anisotropically oriented magnetic powder, making it easier for the magnetic field to reach deep inside.

In addition, as described in 4-4, since the magnetic field is applied efficiently and the force that orients the magnetic powder is large, it is now possible to use high-performance materials containing a large amount of magnetic powder, and even higher-performance plastic magnets can be obtained. I was able to do so.

[Effects of the invention] In the method for manufacturing an anisotropic resin magnet of the present invention, the entire magnet is anisotropically oriented without leaving zero isotropy, so magnetic efficiency is good. ■ Multipolar anisotropic orientation is low. It can be performed magnetically efficiently using energy. ■Multi-polar anisotropic orientation extends deep into the resin magnet, resulting in an anisotropic resin magnet with good performance. ■Increased magnetic powder content for high performance. It has the advantage that even materials with poor fluidity can be easily oriented.

[Brief explanation of drawings]

Fig. 1-1 is a schematic cross-sectional view of a mold for multipolar anisotropic molding and orientation according to the present invention, and Fig. 1-2 shows the magnetic flux in a state where a magnetic field for radial anisotropic orientation according to the present invention is applied. FIG. 1-3 is a schematic diagram showing the flow and orientation of magnetic flux when a multipolar anisotropic alignment magnetic field is applied after demagnetization. -4 is a graph showing the excitation current waveform flowing through each coil, and Figures 2-1 and 2-2 are schematic diagrams of the mold magnetic pole part and molded product obtained by conventional radial anisotropic orientation molding. FIGS. 3-1 and 3-2 are schematic diagrams of a mold magnetic pole part and a molded product produced by conventional multipolar anisotropic molding orientation. 1 Ni for niradial anisotropic orientation 2 S pole for niradial anisotropic orientation 3 Molded product 4: Ferrite magnetic powder 5 Magnetic flux flow for niradial anisotropic orientation 7 Radial anisotropic orientation magnetic field generating coil 8: Coil for demagnetization 9: Coil for pulsed magnetic field for multipolar anisotropic orientation Coil 10: Magnetic field for multipolar anisotropic orientation IO a Graph representing the current waveform for niradial anisotropic orientation b: Pulse current for demagnetization Graph C representing the waveform: Graph representing the current waveform for multipolar anisotropic orientation caused by a pulsed magnetic field Figure 1-1 Figure 1-3 Figure 1-4 Figure 2-1 Figure 2-2 Figure 3-1 Figure 3-2

Claims (1)

[Claims] A multi-purpose method comprising the step of maintaining a resin magnet composition containing magnetic powder in a molten state within a cylindrical cavity and applying a magnetic field to the cavity to anisotropically orient the magnetic powder. A method for producing a polar anisotropic resin magnet, which comprises applying a radial or axial anisotropic orientation magnetic field from the inner and outer peripheral sides of the cavity to orient the magnetic powder in a radial or axial anisotropic orientation. A multipolar anisotropic resin magnet characterized by comprising a step of applying a multipolar anisotropic orienting magnetic field from the outer circumferential side of the cavity to orient a part of the magnetic powder in a multipolar anisotropic manner. manufacturing method.