JPH0626162B2 - Method for manufacturing C-type anisotropic resin bonded magnet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a C-type anisotropic resin bonded magnet,
In particular, it is possible to provide a thin-walled C-shaped magnet, and The C micromotor can be miniaturized and high performance can be realized.

[Prior art]

Conventionally, D.I. The C-type magnet used in the C micromotor is, firstly, a ferrite-based sintered magnet. The second is a rubber or plastic magnet. However, the conventional products have the following drawbacks. First, the first example is an isotropic sintered product, which has a low magnetic performance of about | BH | max 0.9 to 1.1 MGOe. For uniaxial anisotropic sintered magnets, use | BH | max
It can be increased from 3.5 to 4.0 MGOe, but the wall thickness t is 2 m / m or more,
There was a problem that the angle θ could only be less than 130 °.
Therefore, by all means, D. The C micromotor had constraints in terms of output characteristics and dimensions. Further, even if radial anisotropy is imparted, there is a drawback that it cracks during sintering.

The rubber plastic ferrite magnet of the second example has a low performance of | BH | max0.6MGOe even if it is given anisotropy.
There was a problem that the use was limited.

[Purpose] It is an object of the present invention to eliminate such drawbacks and to provide a method of improving the performance of a C-type anisotropic resin bonded magnet and of low manufacturing cost and high mass productivity. Another object of the present invention is to provide a C-type anisotropic resin bonded magnet which can be anisotropically uniaxially or radially and is not limited in thickness and length.

〔Overview〕

The specific configuration of the present invention will be described below. C of the present invention
The shaped magnet refers to the following.

The cross-sectional shape of the same magnet shown in FIG. 1-C is as follows when expressed by the combination of r ₁ and r ₂ , the fan angle θ, and the wall thickness t.

r ₁ …… 4 mm r ₁ or more r ₂ …… 3.8 m / mr ₂ or more t …… r ₁ −r ₂ = 0.2 m / m or more θ …… 180 ° or less Magnet powder transitions with yttrium and runtnide rare earth metals It is a compositional alloy composed of metals. Specifically, the following rare earth intermetallic compound alloys are represented by the general formula. SmCo ₅ Sm (Co _0.9 Cu _0.1 ) ₅ Sm (Co _bal Fe _0.1 Cu
_0.1 ) _7.2 , Sm (Co _bal Cu _0.1 Fe _0.2 Zr _0.01 ) _7.3 , Sm (Co _bal
Cu _0.07 Fe _0.15 Ti _0.015 ) _7.4 , Sm (Co _bal Cu _0.08 Fe _0.22
Zr _0.028 ) _8.35 , Sm (Co _bal Cu _0.06 Fe _0.32 Zr _0.018 ) _7.6 ,
Sm _0.7 Pr _0.3 (Co _bal Cu _0.07 Fe _0.24 Zr _0.02 ) _7.6 Sm (Co
_bal Ni _0.1 Fe _0.2 Cu _0.10 ) _7.2 , Sm _0.8 Ce _0.2 (Co _bal Cu _0.1
Fe _0.15 Zr _0.01 ) _7.4 , Sm _0.8 Y _0.2 (Co _bal Cu _0.12 Fe _0.20 )
_7.4 Others Crystal anisotropic ferromagnetic materials composed of rare earth metals and transition metals can be applied.

A mixture consisting of 50 vol% to 85 vol% of the ferromagnetic powder and the balance resin binder (binder) was previously kneaded with a kneader.
A compound must be prepared by heating and kneading at 250 to 350 ° C. The ferromagnetic powder is set to 50% by volume or more because the magnetic performance of the resin-bonded magnet including the ferromagnetic powder and the resin binder depends on the volume ratio of the ferromagnetic powder. The reason why it is set to 85% by volume or less is that, even if the volume ratio of the ferromagnetic powder is too high, the powder in the material becomes a molding resistance and reduces the processing rate. Here, as the thermoplastic resin, the following materials are used. Nylon 6, Nylon 6-6, Nylon 12, Polyethylene, EVA, PP, PES, PB
An epoxy resin, a phenol resin, or the like is used as the T, PS, or PEEK thermosetting resin. Next, the mixture (compound) is chopped into pellets, inserted into a magnetic field extrusion molding apparatus, heated to 120 to 380 ° C., and in a fluid state, the die space is extruded under pressure to obtain the product shape and Determine performance. The temperature is set to 120 ° C. or higher in order to obtain a magnet having good heat resistance, and the temperature is set to 380 ° C. or lower because the ferromagnetic powder is easily oxidized. At this time, the magnetic field in the space of the die is not preferably applied in the magnetic field unless approximately 6 KOe to 20 KOe is applied. The extruded C-shaped magnet is cut into a desired length and incorporated into a motor for use. The C-type resin-bonded magnet of the present invention is Used for C motors, meters, sensors, relays, etc.

[Example-1] Fig. 1-A is a sectional view of a magnetic field compression molding apparatus when a conventional ferrite magnet is formed into a C shape. The conventional method is 1, 2, which also functions as a pole piece and a pressure ram, and a mold 3,
Ferrite powder was pressure molded at 7 in a magnetic field at 4. The pressure at this time was 1 ton / cm ² , and the magnetic field was 6 KOe. The magnetic field is applied to the coils 5 and 6 by the D.I. A C current was applied.
The pressure was 1 ton / cm ² between the first and ^second hydraulic pressures. Next, demagnetization was performed to obtain a green body shown in FIG. 1-B. Here, the moldings are still fragile and difficult to handle. Next, the magnet sintered by heating at 1100 ° C. for 1 hour in an atmospheric furnace was severely deformed by shrinkage and the dimensional and shape accuracy was poor, so a C-shaped magnet was obtained by grinding.

The method of the present invention produced a C-shaped magnet under the following conditions. Sm C
o ₅ (samarium cobalt) alloy with a grain size of 3 μm to 10 μm
2 kg of magnetic powder whose particle size was adjusted to an average particle size of 4.8 μm was prepared. Next, nylon 12 was mixed as a resin binder. The ratio of magnet powder to resin binder is 65 magnets.
This mixture is used as PCM- with vol% / 35vol% binder.
The mixture was heated and kneaded at 320 ° C. with a 45-type (Ikegai Tekko) kneader. Next, the obtained bounds are C-shaped resin-bonded magnets shown in FIG. 2A by an extruder in a magnetic field.
I got C. The compound C of the present invention C-type magnet is
It is inserted from the hopper 7 and pushed forward by the screw 8. The compound 10 is heated to 280 ° C. by the heater 11 in the space of 14 dies, becomes a fluid state, and is easily oriented in the magnetic field. At this time, the magnetic field is applied to the 13-a, b coil, 12-a, b pole piece electromagnet by D. A C current was applied to generate a magnetic field of about 10 KOe in a 14-die space.

The magnetic field direction is uniaxial anisotropy in the C-type magnet thickness direction. The thickness t of the C-shaped magnet is 1.0 m / m, r ₁ 9 m / m, r ₂ 8 m / m
Then, θ is a fan shape of 130 °. Thus, the magnet of the present invention extruded in a magnetic field and cooled and solidified by 15 cooling coils is
It is cut into a desired length and completed as a magnet. The characteristics of the C-shaped magnet produced by the method of the present invention are shown in Table 1.

The magnetic performance was measured with a VSM (vibrating sample type magnetometer). The magnetic energy product about twice that of the conventional method was obtained. As described above, the conventional method is one in which barium ferrite magnet powder is molded in a magnetic field and then sintered. Impact resistance is height 1.5
The cracks and cracks of the C-shaped magnet when dropped on the concrete floor from m were examined. In the conventional method, all 5 specimens were cracked, requiring careful handling. On the other hand, it was proved that the C-shaped magnet of the present invention was excellent in mechanical properties without causing cracking and chipping. Next, the crush strength of the C-shaped magnet was examined by the method shown in FIG. The magnet 18 was placed on a flat plate 19 and pushed in the direction of the arrow through the upper part, the push rod 20, the spring 21, and the meter 22, and the strengths until the magnet breaks were compared. It was found that the C-shaped resin bonded magnet of the present invention was about 1.5 times stronger.

Example-2 In this example, D. C-shaped magnets for C-micromotors and various shapes were made. FIG. 4-A shows a magnet made of the barium ferrite magnet of the comparative example. FIG. 6 is a cross-sectional view when assembled in a C motor yoke. Fig. 4-B, C
Is a C-shaped resin-bonded magnet according to the method of the present invention, which was produced by extrusion molding while imparting radial anisotropy. The magnet powder is 2-17 system Sm _0.8 Y _0.2 (Co _bal Cu _0.1 Fe _0.22 Ti
_0.01 ) _7.4 alloy composition, of course, magnetic hardening heat treatment. The particle size distribution is 3 μm to 80 μm. The reason for setting such a range is that the volume ratio of the magnet must be increased in order to improve the magnetic performance, but this is not enough and the particle size of the ferromagnetic powder needs to have a certain degree of distribution. As the binder, a compound in which 35 vol% of nylon 12 was added and rooted was used. This compound was heated (280 ° C.) in a heating magnetic field 1 using an extrusion molding apparatus shown in FIG. 2A.
Radial orientation was performed while adding 2 KOe to obtain a C-type anisotropic resin bonded magnet.

Next, it was incorporated in a pure iron motor case, pulse-magnetized, and the magnetic flux distribution was measured. A search coil was placed in the motor space and the change in the flux was investigated. Although the data are shown in FIG. 5, the magnets B and C of the present invention are shown in FIG.
Corresponding to C, the high value (flux) is large and the area is large compared to the conventional example. As a motor, we have developed a micro motor that can take large torque and is highly efficient.

〔effect〕

As described above in detail, the C-type anisotropic resin bonded magnet of the present invention has the following advantages. By extrusion molding, magnetic field orientation treatment to give magnetic performance in one process, high filling of magnet powder, and fabrication of dimension and shape are performed, so mass productivity is extremely high and cost reduction can be easily achieved. There are advantages. Also, the surface magnetic flux density is 30% compared to the conventional product.
There is a high advantage of up to 50%. Furthermore, since the C-shaped shape can be changed in thickness in the circumferential direction and can be easily thinned, D.I. There is an advantage that the cogging torque of the C motor can be easily reduced. Taking advantage of these advantages, D. It has applications in fields such as C motor magnets, generator magnets, and meter magnets.

[Brief description of drawings]

FIGS. 1A, 1B, 1C show a magnetic field press ... A, a molding portion ... B, and a sectional shape ... C for manufacturing a C-shaped magnet of a comparative example. FIG. 2 is an extrusion molding apparatus for producing a C-type anisotropic resin bonded magnet in the method of the present invention ... A, a magnet appearance ... B, and a magnet cross-sectional view ... C. FIG. 3 shows a magnet collapse test method in the method of the present invention. FIG. 4 is a ray mout of a C-shaped magnet incorporated in a motor and after shape A ... Examples of conventional method B, C ... Method of the present invention. FIG. 5 is a graph showing the magnetic field distribution in the motor magnets of FIGS. A: Conventional method (motor of FIG. 4-A) B: Inventive method (motor of FIG. 4-B) C: Inventive method (motor of FIG. 4-C)

Claims (1)

[Claims] 1. A method for producing a C-type anisotropic magnet in which a rare earth magnet powder is bonded with a resin, wherein a mixture containing 50% by volume to 85% by volume of the rare earth magnet powder having a particle diameter of 3 μm to 80 μm and the remainder being resin. A method for producing a C-type anisotropic resin-bonded magnet, which comprises orienting the rare earth magnet powder while applying a magnetic field and making it by a pressure molding method in a state of being heated to 120 ° C to 380 ° C.