JPS62186507A - Method and mold for manufacturing polar anisotropic resin magnet - Google Patents

Abstract

PURPOSE:To obtain a resin magnet, whose magnetic field is improved, by providing two or more ferromagnetic yokes at outer pole parts of a cavity, arranging a permanent magnet on each of fives surfaces out of six surfaces of the yoke other than the surface for an external pole, and increasing the magnetic field in the cavity. CONSTITUTION:A magnetic field is applied to the composition of a resin magnet, and the polar anisotropic resin magnet is manufactured by injection molding. At this time, two or more approximately rectangular-parallelopiped shaped yokes 1 are provided at the outer parts of a cavity 5 having cylindrical parts. Out of the six surfaces of the yoke 1, each of five surfaces other than the surface for an outer pole is provided with a permanent magnet 2. Then the magnetic field leaking from the yoke 1 other than the outer pole part is suppressed by the repelling magnetic field of the magnet 2. Thus the magnetic field in the cavity 5 is increased. Therefore, the resin magnet, whose surface magnetic field is improved is obtained.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a method for producing a polar anisotropic resin magnet and a mold for producing it, and more specifically, to a method for producing a polar anisotropic resin magnet, and more specifically, it relates to a method for producing a polar anisotropic resin magnet, and more specifically, a method for producing a polar anisotropic resin magnet. The present invention relates to a method for manufacturing a polar anisotropic resin magnet, which prevents leakage magnetic fields, concentrates and increases the magnetic field within the mold cavity, and improves magnetic properties, and a manufacturing mold.

"Prior Art and Problems" Conventionally, isotropic magnets and radially anisotropic synthetic resin magnets having a cylindrical or cylindrical portion for multipolar magnetization are known. Radial anisotropy provides a larger surface magnetic field than isotropic, but it is still far from reaching a fully satisfactory level.

For example, Japanese Patent Application Laid-Open No. 56-69805 discloses that, in order to obtain a multipolar anisotropic magnet with low equipment costs, a magnetic field is applied by a permanent magnet placed in a mold for magnetic orientation. A model has been proposed. However, in a mold having such a structure, the magnetic field within the cavity is not necessarily sufficient, and therefore the magnetic properties of the obtained product are not necessarily satisfactory.

Furthermore, in Japanese Patent Application Laid-Open No. 60-47409, a yoke is provided at a position corresponding to the magnetic pole portion around the gap, and a permanent magnet for generating magnetomotive force is installed outside the yoke, and the adjacent yokes are A method of manufacturing an anisotropic composite magnet using a mold having a permanent magnet between which a repulsive magnetic circuit is formed between the permanent magnet and the permanent magnet is disclosed. However, even in such a structure, the magnetic field from the permanent magnet for generating magnetomotive force leaks between the yokes, and the magnetic field within the cavity does not increase as expected.

"Means for Solving the Problems" In view of the above circumstances, the present inventors completed the present invention as a result of intensive research to solve the above problems.

That is, the first aspect of the present invention is a method for manufacturing a polar anisotropic resin magnet by injection molding a resin magnet composition while applying a magnetic field. A substantially rectangular parallelepiped ferromagnetic yoke of 211I or more is provided in the yoke, and permanent magnets are arranged so that the same poles are in contact with each of five of the six faces of the yoke, excluding the outer pole acting part. , the leakage magnetic field from the outer pole action part array of the yoke is suppressed by the repulsion magnetic field of the permanent magnet,
The second aspect of the present invention includes a method for manufacturing a polar anisotropic resin magnet, characterized in that the magnetic field within the cavity is increased.
is provided with two or more substantially rectangular parallelepiped ferromagnetic yokes in the outer pole part of a cavity having a cylindrical shape or a cylindrical part, and each of the five faces of the six faces of the yoke except for the outer pole acting part. The mold includes a mold for manufacturing a polar anisotropic resin magnet, in which a permanent magnet is disposed, and the permanent magnet has the same pole in contact with the coke.The present invention will be described based on drawings showing embodiments. Then, FIG. 1(A) is a conceptual diagram of a rectangular parallelepiped-shaped yoke (1), and the yoke (1) has six surfaces (A) to (F). If the surface is (A), then there are five surfaces (B) to (F) except for the outer pole active surface (A). FIG. 1(B) is a conceptual diagram of a unit magnetic pole in the present invention,
Five surfaces (B) of the yoke (1) shown in Figure 1 (A) ~
At (F), attach the permanent magnets (2b) to (2r) so that the same polarity is the yoke (
1) are arranged so as to be in contact with each of the five surfaces.

In the figure, a permanent magnet (2b) is a permanent magnet for generating magnetomotive force.

FIG. 2 is a conceptual diagram for explaining the structure of a yoke (1) and a permanent magnet (2) when obtaining a multipolar anisotropic magnet. That is, as shown in the figure, the yoke (1) and the permanent magnet (2
), the combination (X) and (Y) are combined so as to have a predetermined number of magnetic poles, and a structure as shown in (Z) can be obtained.

3(A) to 3(C) are cross-sectional views showing embodiments of the mold of the present invention, and FIG. 3(B) is an enlarged sectional view of Q-Qq section of FIG. 3(A), and FIG. (C) is an enlarged sectional view of the main part RR of FIG. 3(B). In these figures, the yoke (1) and the permanent magnet (2) are combined as shown in the outer pole non-magnetic part (3), and these and the inner pole non-magnetic part (3) are combined.
4), a cylindrical cavity (5) is formed between the two.

Cavity (5) has runner (6) and sprue (7)
6 (9) connected to the nozzle (8) of the molding machine through
) is the ejection bottle, and P is the parting surface.

Examples of non-magnetic materials used in the present invention include austenitic stainless steel such as 5US304, copper-helylium alloy, and YH
High manganese steel such as D50 (manufactured by Hitachi Metals) or N-
All known materials such as non-magnetic cemented carbide such as No. 7 can be used. Further, the yokes (ferromagnetic materials) used in the present invention include carbon steels such as 5IOC, 54QC, 545CXS55C, pre-hardened steel, 5KD4.5KD5.5KD6.
All known ferromagnetic mold materials such as die steel such as 5KDl1 can be used.

In the present invention, it is a preferred embodiment to harden the surfaces of the walls constituting the cavity in order to improve shot resistance and improve the dimensional stability of the product. The hardening treatment is preferably performed to a Vickers hardness of 1500 HV or more. The method of hardening treatment is not particularly limited, but for example, if a nonmagnetic material is used whose surface is first carburized to form a carburized layer and then a hardened layer of heavy metal carbide is formed by some method, the purpose can be achieved. achieved. The carburizing method may be any of the known solid carburizing method, gas carburizing method, and liquid carburizing method.

The method for applying the heavy metal carbide surface hardening layer may be any of the known carbide diffusion and infiltration treatments (T, D process) using the molten salt method, chemical vapor deposition, physical vapor deposition, and the like. Suitable carbide coating layers include titanium carbide, niobium carbide, vanadium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, and kuntal carbide.

The thickness of the carbide coating layer is preferably 1 to 100 μm, more preferably 5 to 50 μm, and even more preferably 10 to 20 μm.

If it is less than 1 μm, the wear resistance is not sufficient, and the force is less than 100 μm.
If it exceeds this, it becomes magnetic, so if it is used as a non-magnetic mold material, it will disturb the magnetic circuit and, as a result, the magnitude of the magnetic field expected within the cavity will decrease.

Like the yoke, the permanent magnet used in the present invention has a rectangular parallelepiped cross section close to an inverted trapezoid, and its materials include ferrite magnets, alnico magnets, and Fe-cr-c.

Magnet, rare earth cobalt magnet, Pt-Co magnet, Mn-A
All known permanent magnets such as I-C magnets and Nd-Fe-B magnets can be used, but for practical purposes, Fe-Cr-Co magnets,
It is desirable to select from rare earth cobalt magnets and Nd-Fe-B magnets.

Known polymers are used as the resin used in the present invention, such as EVA, polyamide, PP, PE, PVC.
, acrylic resin, methacrylic resin, chlorinated polyethylene resin, PPS, polycarbonate, etc. may be used alone or in combination. As the magnetic powder used in the present invention, magnetoplumbite type Sr or 13a ferrite is suitable. Known additives can be used depending on the purpose. In other words, for the dispersibility of ferrite powder, an appropriate surface treatment agent is used depending on the resin used, such as silane coupling agents, titanate coupling agents, higher fatty acids and their metal salts, and phosphonate esters. include. In addition, stability improvers, antioxidants,
Additives such as ultraviolet absorbers and lubricants are also used as appropriate depending on the purpose and the relationship with the resin.

"Examples" The present invention will be described below based on Examples, but the present invention is not limited to these in any way.

Example 1, Comparative Examples 1 and 2 Magnetic field orientation injection molding was performed using the molds shown in FIGS. 3(A) to 3(C) to produce cylindrical resin magnets. As a permanent magnet, Br: 9000G 5iHc: 82
000e, (BH) IIax: 19 M
GOe rare earth cobalt magnets were used. The shape of the cavity was 20 mm in inner diameter, 2611 in outer diameter, and 20 n+ in length.

For comparison, as Comparative Example 1, the above-mentioned JP-A-56-698
The mold described in Publication No. 05 (a structure in which a permanent magnet for generating magnetomotive force is arranged in a non-magnetic material constituting the outer pole), and the mold described in Japanese Patent Application Laid-Open No. 60-47409 as Comparative Example 2 (
Injection molding was carried out in the same manner except that a structure in which permanent magnets for repulsive magnetic circuits were arranged on both sides of the yoke was used. The results are shown in Table 1.

The resin (bellet) used, injection conditions, magnetization conditions, magnetization conditions, and surface magnetic field measurement method were as follows.

Resin (bellet): rFPA190J (manufactured by Dainippon Ink and Chemicals) Injection conditions: Molding machine: Mold clamp 50 Molding machine Injection rate: 27cc/see Injection pressure: 1.7t/, :ffl Temperature = 290°C Cooling time: 30sec Mold temperature: 100°C Demagnetization conditions: 1
In a damped oscillating magnetic field at 500 μFX and 1500 V, complete de-boring was achieved to below [G].

Magnetization conditions: The magnetizing yoke rlr was aligned with the outer pole yoke of the mold.

Also, align the orientation surface with the magnetizing yoke surface, and apply 100μFX1
Magnetization was carried out by flowing a maximum current of 2000A at 00OV.

Surface magnetic field measurement method: Using a Bell Gaussmeter, the probe was placed on the magnetized surface to measure it.

Table 1 shows the measurement results of the surface magnetic fields of the ring-shaped resin magnets obtained in Example 1, Comparative Example 1, and Comparative Example 2.

As shown in Table 1, "Operations and Effects," 2, according to the present invention, as is clear from Table 1, it is possible to provide a resin magnet in which the surface magnetic field is more oriented than products made with conventional molds. It can be widely applied to various motors that are expected to produce larger torque, such as PM type stepping motors, I)C motors, DC brushless motors, AC motors, etc., and if the same torque is expected, the rotor It has many advantages such as being able to be made smaller, and its usefulness in industry is extremely large.

[Brief explanation of drawings]

FIG. 1(A) is a conceptual diagram of a rectangular parallelepiped yoke used in the present invention, and FIG. 1(B) is a conceptual diagram of a unit magnetic pole used in the present invention.
IX conceptual diagram, Figures 2 (X) to (Z) are conceptual diagrams for explaining the configuration of the yoke and permanent magnet of the present invention, and Figure 3 (A)
~(C) shows embodiments of the mold of the present invention, and FIG. 3(A)
is a cross-sectional view, and FIG. 3(B) is a cross-sectional view taken from Q-Q in FIG. 3(A).
The sectional view, FIG. 3(C), is a RR sectional view in FIG. 3(B). 1... Yoke 2... Permanent magnet 3... Outer pole non-magnetic part 4... Inner pole non-magnetic part 5... Cavity 6... Runner 7... Sprue 8. ...Nozzle 9...Ejection bottle P...Parting surface Fig. 1 Fig. 2

Claims (1)

[Claims] 1. In a method for manufacturing a polar anisotropic resin magnet by injection molding a resin magnet composition while applying a magnetic field, the outer pole portion of a cavity having a cylindrical shape or a cylindrical portion is By providing two or more substantially rectangular parallelepiped-shaped ferromagnetic yokes, and arranging permanent magnets so that the same poles are in contact with each of five of the six faces of the yokes, excluding the outer pole acting part,
A method for manufacturing a polar anisotropic resin magnet, characterized in that leakage magnetic fields from areas other than the outer pole acting portion of the yoke are suppressed by a repulsive magnetic field of a permanent magnet, and the magnetic field within the cavity is increased. 2. Two or more substantially rectangular parallelepiped-shaped ferromagnetic yokes are provided in the outer pole portion of the cavity having a cylindrical shape or a cylindrical portion,
A metal for manufacturing a polar anisotropic resin magnet, in which a permanent magnet is arranged on each of five of the six surfaces of the yoke, excluding the outer pole acting part, and the permanent magnet has the same polarity in contact with the yoke. Type. 3. The mold according to claim 1, wherein adjacent yokes have opposite polarities. 4. The mold according to claim 2, wherein adjacent yokes sandwich one permanent magnet.