JP2002208529A - Manufacturing method of annular magnet and raw material for annular magnet and resin for cutting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a thin annular magnet, particularly a sintered magnet having radial anisotropy with excellent mass productivity and yield and a raw material for working capable of being efficiently cut and worked by increasing the strength of raw material itself for the ring-shaped magnet. SOLUTION: The outer circumferential section of a cylindrical magnet raw material is bonded and fixed onto an outer case as a rotating rotor for a motor or the inner circumferential surface of an annular yoke by using the cylindrical magnet raw material sintered in required wall thickness thicker than aimed wall thickness, and fixed to a jig together with the outer case or the annular yoke and an inner circumferential surface is ground, the whole is worked in the annular magnet having a required inside diameter in aimed wall thickness, and a ground worked surface or the like is coated with a resin for protection as required.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin ring-shaped magnet, particularly a ring-shaped magnet capable of mass-producing a sintered ring-shaped magnet having radial anisotropy with a high yield, and further improving the strength of the magnet material itself. The present invention relates to a method of manufacturing a ring-shaped magnet, a material for a ring-shaped magnet, and a resin for cutting, which provide a processed material for a ring-shaped magnet that can be efficiently cut.

[0002]

2. Description of the Related Art As for ring magnets for motors, cast materials such as Alnico magnets require time and effort to produce ring magnets. However, rare earth-containing bonds and sintered magnets have become the mainstream at present due to demands for smaller, lighter, and higher-performance motors.

[0003] In addition, ring-shaped magnets have a
Press-bonded or injection-molded bonded magnets,
Those using sintered magnets sintered after press molding and subjected to cutting are often used.

[0004] On the other hand, HDDs have been rapidly becoming smaller in unit size and larger in capacity along with miniaturization.
Motors are required to have high loads and high rotation speeds. In particular, it is necessary to improve the performance of the ring-shaped magnet fixed to the rotating rotor side and to increase the dimensional accuracy so that an appropriate magnetic gap can be set.

[0005]

In order to reduce the size, weight and performance of a motor, a ring magnet having a high-performance rare earth-containing composition and having radial anisotropy has been demanded. Further, there is a demand for a so-called thin ring-shaped magnet which is a sintered magnet capable of realizing higher performance and which has a small thickness in a radial direction.

However, in order to realize a thin ring-shaped magnet with a sintered magnet, it is necessary to increase the filling ratio of the magnetic powder into the mold before press molding, and to press-mold without cracks or chips. It is known that there are many problems to be solved, such as sintering.

Particularly, in the case of a ring-shaped magnet having radial anisotropy, if the thickness in the radial direction is small, it is extremely difficult to improve the orientation of the magnetic powder and increase the filling rate in the mold.
Obtaining a thin ring-shaped sintered magnet has a problem that the yield is extremely poor.

The present invention provides a method capable of mass-producing thin ring-shaped magnets, particularly sintered magnets having radial anisotropy, with good yield, and efficiently improving the strength of the ring-shaped magnet material itself. An object of the present invention is to provide a processing material capable of performing a cutting process, and further to provide a cutting resin capable of providing a processing material.

[0009]

The inventor of the present invention has conducted various studies on a processing method for the purpose of producing a sintered magnet having radial anisotropy with high productivity and good yield. Attention was paid to using a cylindrical magnet material fired with a wall thickness and to improving the strength of the magnet material in advance to prevent cracking and reduction during firing.

The inventor fixed the outer peripheral portion of the cylindrical magnet material to the inner peripheral surface of an outer case serving as a rotating rotor of a motor or the inner peripheral surface of a ring-shaped yoke of a magnetic circuit, for example.
Fix the outer case or ring-shaped yoke together with the jig and grind the inner peripheral surface of the cylindrical magnet material so that it can be processed into a ring-shaped magnet with the required wall thickness and the required inner diameter. It has been found that it is convenient to apply it to a processed surface or the like.

It has been found that the following effects can be obtained by the above steps. The adhesion to the motor case and the ring-shaped yoke has the same effect regardless of the inner or outer peripheral surface of the case or the yoke. 1) Since the thickness can be made larger than the intended thickness, the mechanical strength of the sintered cylindrical magnet material can be greatly improved to facilitate the grinding process. 2) Since the thickness can be made larger, the cylindrical magnet can be formed at the time of molding in a magnetic field. The orientation of the magnetic powder of the material is remarkably improved, and it can be manufactured with good yield. 3) The inner diameter of the outer case and yoke, which is built into the motor and is processed with high accuracy, is cut as a reference. The required magnetic gap with the fixed side coil can be set with high accuracy. 4) Even if a rare earth-containing magnet or the like that requires a surface protective film is bonded to the outer case or yoke or after processing, a small-diameter roll, or It is possible to easily form a film by coating a cylindrical or column-shaped coating member, and the protective film process can be simplified and reduced.

In forming the cylindrical magnet material, colloidal silica or a liquid phase body containing ultrafine particles in which ultrafine particles are uniformly dispersed in a resin liquid or liquid paraffin so that they cannot be centrifuged is kneaded, and then fired. It has been found that the reduction in time can be prevented, the dimensional accuracy can be greatly improved, and the strength of the molded body can be improved in advance, so that cracking and chipping during and after firing can be prevented.

Further, the inventor has used a resin solution containing fine silica in a resin such as a urethane resin or an acrylic resin as an adhesive and a paint, and used this as a paint to apply a cutting resin film to the entire cylindrical magnet material in advance. It was invented that a film be formed on the substrate.

Adhesives and paints containing fine silica have the following characteristics: 1) excellent adhesion to the magnet material and high surface protection ability; 2) remarkable improvement in grinding workability by fine silica; It has been found that the adhesiveness to a support member and the like and the adhesion strength are excellent.

Further, by forming a cutting resin on the entire cylindrical magnet material in advance, 1) excellent adhesion to the magnet material and high surface protection ability, and 2) sintering of the cylindrical magnet material can be achieved. It is possible to greatly improve the mechanical strength,
3) The grinding property is remarkably improved by the fine silica. 4) The grinding property is remarkably improved by using together with the above-mentioned means for fixing to the inner peripheral surface or the outer peripheral surface of the motor case, and the mass productivity and the yield are improved. It has been found that a ring-shaped magnet can be manufactured. 5) The resin liquid has excellent adhesion to the surface of the magnet material after cutting and has a high surface protection ability.

Further, when the cylindrical magnet material is molded, the exposed surface of the cylindrical magnet material is coated and impregnated with the ultrafine particle-containing liquid phase material which is kneaded, or impregnated while applying steam to impregnate the material. It has been found that the strength is remarkably improved, the storage and transfer up to the subsequent process are easy and simple, and the protection ability of the magnet itself is excellent.

Furthermore, the inventor of the present invention has found that a cylindrical magnet material on which a cutting resin has been formed in advance has a high mechanical strength and is easy to handle, and a cylindrical magnet material mounted on a support member is even easier to handle. From these facts, it has been found that storage and transfer up to the subsequent process are easy and simple, and the magnet itself has excellent protection ability.

The inventor has found that, by increasing the thickness of the cylindrical magnet material in the outer diameter direction and forming it, the mechanical strength of the sintered body is improved and the grinding process is facilitated. In addition, the mechanical strength of the sintered body is improved by forming it into a long case in the axial direction of the cylindrical magnet material and bonding it in a long case or yoke. It has been found that cutting the entire case and yoke together makes it possible to produce a ring-shaped magnet with high productivity and good yield, and completed the present invention.

That is, according to the present invention, there is provided a step of fixing an outer peripheral surface or an inner peripheral surface of a cylindrical magnet material to an inner peripheral surface or an outer peripheral surface of a support member, and grinding the inner peripheral surface or the outer peripheral surface of the raw material. A method for manufacturing a ring-shaped magnet, comprising a step of processing into a ring-shaped magnet having a required inner diameter or outer diameter.

Further, the present invention can be combined with the above-described steps by adding the following various steps. A step of cutting the material into a plurality of pieces together with the support member in the direction perpendicular to the axial direction after fixing to the support member, a step of forming a resin film on an exposed surface of the material after the processing step, In the step of coating with resin, the step of forming a resin film on the exposed surface of the material after fixation with the support member, and the manufacturing step of obtaining a cylindrical magnet material in advance, colloidal silica, or ultrafine particles in a resin liquid or liquid paraffin The step of kneading the ultrafine particle-containing liquid phase obtained by mechanically and uniformly dispersing the powder into the powder for the molded body of the cylindrical magnet material, before or after the processing step, the colloidal silica, or the ultrafine particles in a resin liquid or liquid paraffin. A step of impregnating the ultrafine particle-containing liquid phase material in which the powder is mechanically non-centrifugally dispersible uniformly from the surface layer of the exposed surface of the material,
In the step of impregnating the ultrafine particle-containing liquid phase in an atmosphere containing steam, the step of fixing with the application of an adhesive, or the step of forming a resin, the outer peripheral surface or the inner peripheral surface of the cylindrical magnet material is interposed through a required gap. An adhesive or resin is supplied into the required gap by using a cylindrical or columnar coating member, and the adhesive or the resin is moved by the relative movement of one or both of the cylindrical magnet material and the coating member on the same axis. Coating the outer peripheral surface or the inner peripheral surface of the cylindrical magnet material.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a target magnet is a thin ring-shaped sintered magnet having a radial anisotropy which is most difficult to manufacture, but a target magnet is magnetically isotropic. It may be any one of the properties of anisotropy and anisotropy, and is applicable to a bonded magnet and a cast magnet as well as a sintered magnet.
As the material, any known magnet composition can be applied. Particularly, in the case of a rare-earth-containing magnet such as an Sm-Co-based or Fe-BR-based magnet, its productivity can be improved, which is preferable. The material.

In the present invention, as a method of manufacturing the cylindrical magnet material, a known method is appropriately selected and adopted according to the target magnet material and the characteristics of the magnet. For example, in the production of a cylindrical magnet material for a ring-shaped sintered magnet having radial anisotropy, a mold having an axial height dimension set to a target dimension is used, and a thickness in an outer diameter direction is set to a target dimension. Set it larger,
The filling property of the magnetic powder into the molding space of the mold can be improved, and the orientation in a magnetic field can be improved. In this case, either a single-cavity mold or a multi-cavity mold can be adopted.

Further, the height in the axial direction is increased.
It is also possible to obtain a so-called long cylindrical molded body, by setting the thickness in the outer diameter direction much larger than the target dimensions,
The filling property of the magnetic powder into the molding space of a mold that is long in the axial direction can be improved, and the orientation in a magnetic field can be improved.

In the present invention, the supporting member may be any of various types of cases for facilitating the handling of the magnet material, an inner / outer case serving as a rotating rotor for a motor or a fixing case not rotating, a moving magnet type or a moving coil type. Depending on the process used to obtain the ring-shaped magnet, the form of the final product, etc., such as the case used for the actuator, the yoke that constitutes the magnetic circuit, and the jig itself of the cutting device or the member that is attached to the jig Any appropriately selected cases can be adopted. Further, the ring-shaped yoke may be a non-integral bulk, for example, a ring having a closed slit.

Particularly in motor applications, the present invention can be applied to either a magnet rotating type or a coil rotating type.
Various cases and yokes can be employed, such as a configuration mounted on the inner peripheral surface of an outer case that becomes a rotating rotor as in the embodiment described later, and a configuration mounted on the outer peripheral surface of the inner case.

Further, the extremely thin aluminum cylinder shown in the second embodiment functions as a supporting member, and when it is mounted on a cutting machine or a rotating rotor, the handling strength of the magnet itself is remarkably improved. is there. In addition, since it functions not only as a supporting member but also as a reinforcing member, a state having an aluminum cylinder can be said to be a magnet material. further,
The same applies to a resin tube or a tube made of resin-impregnated paper instead of this thin aluminum tube.In the case of resin-impregnated paper, wrap it around a magnet material and adhere it. The cutting resin described below is particularly suitable for the impregnating resin because of its excellent penetrating power, adhesive strength, hardness and the like.

In the present invention, the adhesive and the coating resin can be appropriately selected from known adhesives and coating resins according to the magnet material and the material of the supporting member, and can be employed. is there. In particular, when applying for the purpose of rust prevention on grinding, cutting, or cut surfaces, it is appropriate to appropriately select according to the magnet material. When processing such as cutting is performed after application to the magnet material, it is difficult to perform cutting with ordinary resin alone, and therefore, it is desirable to use the cutting resin of the present invention.

In the present invention, the cutting resin is a resin containing fine silica in a coating or bonding resin, and is preferably a resin containing fine silica in at least one of a urethane resin and an acrylic resin. . In any case, in order to obtain good coatability and adhesiveness and excellent adhesion strength, it is desirable that the fine silica is uniformly dispersed in the resin so that it cannot be centrifuged.

As the urethane-based resin and the acrylic-based resin, any of those known as coating or bonding resins can be employed, and various additives selected according to the material of the magnet, the material of the supporting member, the processing step, and the like. Any composition including an agent, a pigment, a solvent, and the like can be employed.

By dispersing the fine silica uniformly in the resin, it is possible to improve the permeability to the adherend and to remarkably improve the machinability such as cutting, grinding, cutting and polishing. . Therefore, the finer the silica, the more preferable the uniform and fine. The average particle size is preferably 500 nm or less, more preferably 100 nm or less, 50 nm or less,
5 nm or less is preferable. The amount of the fine silica in the solution composition or the resin composition is not particularly limited since it varies depending on the application for coating or bonding, the blending type of the resin, the resin, the additive, the solvent, and the like.

In the present invention, the ultrafine particle-containing liquid phase is prepared by mechanically converting ultrafine particles of the nm class into a liquid phase of a resin liquid or liquid paraffin without employing any chemical diffusion means or the like for the particles and the liquid phase. Kneading, the ultrafine particles in the liquid phase consisted of uniformly dispersed non-centrifugally separated, characterized by extremely high penetrating power to the material to be kneaded or impregnated, obtained by this method It is possible to impregnate a molded body or a molded body or a laminated body which has been molded by various molding methods from the surface layer.

The ultrafine particle-containing liquid phase body is prepared by adding SiO ₂ , Al ₂ O ₃ , ZrO ₂ , SiC, SiN, A
The purpose is to uniformly disperse ultrafine ceramic particles of nm class, such as 1N, ZrN, and TiN, and to exert a modifying effect after solidification. Therefore, it is preferable not to use any so-called solvents at all or to use only a small amount.
On the other hand, the resin liquid or liquid paraffin used for the liquid phase body also functions as a so-called binder, so that it is not necessary to use a known binder for the powder for a molded body for producing a magnet material.

As the ultrafine particle-containing liquid phase body, known colloidal silica can be used in addition to a liquid phase of a resin liquid or liquid paraffin described below. This is obtained by stabilizing ultrafine particles of silicic anhydride as a colloidal solution, and various ultrafine particle contents, pH, and viscosities have been put into practical use. Accordingly, it is preferable to appropriately select the above-described properties because the secondary aggregation is as difficult as possible. In particular, when using a colloidal silica to impregnate the surface of the magnet material, the pressure and temperature of steam are used in combination, or a steam press is used in combination, so that the impregnation becomes extremely efficient and impregnates deeply.

As the ultrafine particles, those having at least one form of a spherical form, a porous form, and a fibrous form can be adopted, and the average particle diameter is 100 nm or less, 50 nm or less,
Preferably, as small as 20 nm or less and 10 nm or less, the effect of penetrating into the surface of the molded article or the laminate or the surface material and the effect of modification are high.

The ultrafine particle-containing liquid phase body according to the present invention is characterized in that ultrafine particles are mechanically and uniformly dispersed without being centrifugable. To achieve this by a mechanical kneading means such as a ball mill. It is necessary that the resin liquid has an average molecular weight of three times or less the average molecular weight (formula weight) of the ultrafine particles. More preferably, the resin liquid has a specific gravity of 0.8 to
1.2 is around 1. Liquid paraffin, which is a so-called oil, satisfies the same conditions as the resin liquid, so that ultrafine powder can be mechanically and uniformly dispersed without centrifugation.

The average molecular weight (formula weight) of the ultrafine particles is SiO
_{2: 60.06, Al 2 O 3} : 101.94, ZrO 2: 1
23.22, SiC: 40.07, SiN / Si ₃ N ₄ :
140.3, AlN: 40.99, ZrN: 105.2
3, TiN: 61.91, CaCO ₃ : 100.09.

The most preferred resin liquid for the above ultrafine particles is methacrylic acid or an acrylic resin liquid of various reactants with methacrylic acid. For example, the average molecular weight of the resin liquid is methacrylic acid (MAA). : 86,
Methyl methacrylate (MMA): 100, ethyl methacrylate (EMA): 114.15, n-butyl methacrylate (n-BMA): 142.2. One or more of these are appropriately selected so as to have a required average molecular weight, and further, a water-soluble acrylic resin liquid which has been made water-soluble by a known method is also a preferred embodiment.

The inventor tried to knead the ultrafine powder containing 7 nm of SiO ₂ and 13 nm of Al ₂ O ₃ singly or as a known resin liquid with various paint resins using a ball mill. When the average molecular weight is equal to or about 1.5 to 2 times the average molecular weight of the ultrafine particles, it is most easily mechanically and uniformly dispersed without centrifugal separation. Confirmed that it can be seen.

Particularly in the case of 7 nm of SiO ₂ and MMA,
A completely colorless and transparent liquid phase is obtained even when kneading at least 40%,
Average molecular weight of the resin solution with the liquid phase body can be mixed to other coating resins over three times greater than that of SiO _2, conventionally, 2
Next aggregate such as a direct mechanical polymeric acrylic could not uniformly dispersed in the silicon acrylate, the SiO ₂ 7 nm in in other polymeric resin coating material such as epoxy so as not to centrifuge can mechanically uniformly dispersed Was.

Therefore, particularly, the average particle diameter of the ultrafine particles is 20 n
m, SiO ₂ , Al ₂ O ₃ , ZrO ₂ , SiC, S
In order to prepare a liquid phase body using an ultrafine particle powder containing at least one of iN, AlN, ZrN, and TiN, 50% or more of the resin liquid is three times or less the average molecular weight (formula weight) of the ultrafine particles. Having an average molecular weight of 0.8 and a specific gravity of 0.8
It is desirably about 1.2. The most preferred resin liquid is that 50% or more of the resin liquid is methacrylic acid or a reaction product with methacrylic acid.

In particular, after the surface is impregnated with colloidal silica, the surface of the surface is coated with a liquid phase containing ultrafine particles made of an SiO ₂ -containing acrylic resin, so that the colloidal silica is hardened and solidified by the acidic acrylic resin. In addition to being effective, the magnet material impregnated part and surface
Since the O ₂ ultrafine particles are dispersed and arranged in a large amount, it has an extremely high hardness and supple surface layer in addition to the above-mentioned modification and addition of functions. Also, a suitable insulator SiO
_{(2) Since the} ultrafine particles are dispersedly arranged, eddy current is less likely to be generated in the magnet itself.

The manufacturing method and the material for the ring-shaped magnet according to the present invention will be described below in detail with reference to the drawings. FIG.
As shown in A, a cylindrical magnet material 1 having a required target outer diameter d1 and height h and having an inner diameter d2 smaller than the target inner diameter is separately manufactured.

As shown in FIG. 1B, a two-stage throttle thin cap-shaped case 1 serving as a rotating rotor of a motor is provided.
0 is prepared separately. The case 10 includes a cap part 11 for accommodating a magnet having a large outer diameter and a cap part 12 for accommodating a bearing part having a small outer diameter.

Cap 11 for housing magnet of case 10
The inner diameter is the same as the outer diameter d1 of the cylindrical magnet material 1, and an adhesive is applied to the inner peripheral surface of the cap portion 11 or the outer peripheral surface of the cylindrical magnet material 1 so that the inside of the cap portion 11 as shown in FIG. The cylindrical magnet material 1 is fixed.

When the ring-shaped yoke is used in place of the case 10, the following operation and effect are the same, and the cylindrical magnet material 1 is formed on the inner peripheral surface of the ring-shaped yoke as in the configuration shown in FIG. 3D. The same applies to the case in which the ring-shaped yoke is further fixed to the case 10.

Next, the outer peripheral portion of the case 10 is chucked by the work fixing portion of the cutting device, and the cap portion 1 is fixed.
1 The inner peripheral surface of the cylindrical magnet material 1 bonded and fixed to the inner peripheral surface is cut. At this time, based on the outer diameter of the case 10, the inner peripheral surface of the cylindrical magnet material 1 is finished to an inner diameter d3 of a predetermined size.

When the case 10 to be a rotating rotor is formed and processed with high dimensional accuracy, the inner peripheral surface of the cylindrical magnet material 1 is reduced to an inner diameter d3 of a predetermined size based on the outer diameter of the case 10. When finished, the magnetic gap with the coil built in as the motor can be made the minimum size.

Next, a process of grinding the outer peripheral surface of the cylindrical magnet material and processing it into a ring-shaped magnet having a required outer diameter will be described. As shown in FIG. 2A, a cylindrical magnet material 2 having a required target inner diameter d4 and a height h and an outer diameter d5 larger than the target outer diameter is separately manufactured.

Further, as shown in FIG. 2B, a cylindrical inner case 20 having a two-stage throttle serving as a rotating rotor of a motor is separately manufactured. The inner case 20 includes a large-diameter portion 21 having a large outer diameter for mounting a magnet and a small-diameter portion 2 for storing a bearing portion having a small outer diameter.
And 2.

The outer diameter of the large diameter portion 21 of the inner case 20 is equal to the inner diameter d4 of the cylindrical magnet material 2, and an adhesive is applied to the outer peripheral surface of the large diameter portion 21 or the inner peripheral surface of the cylindrical magnet material 1. The cylindrical magnet material 2 is applied and fixed to the outer peripheral surface of the large diameter portion 21 as shown in FIG. 2C.

Next, the outer periphery of the cylindrical magnet material 1 bonded and fixed to the large-diameter portion 21 is cut by making the outer periphery of the small-diameter portion 22 of the inner case 20 chuck the workpiece fixing portion of the cutting device. At this time, the outer peripheral surface of the cylindrical magnet material 2 is finished to an outer diameter d4 of a predetermined dimension based on the outer diameter of the inner case 20.

When the inner case 20 serving as a rotary rotor is molded and processed with high dimensional accuracy, the inner case 20
When the outer peripheral surface of the cylindrical magnet material 2 is finished with an inner diameter d6 of a predetermined size based on the outer diameter of the above, the roundness is improved and the magnetic gap between the coil and a coil to be externally mounted as a motor is reduced to a minimum size. Becomes possible.

Therefore, in the case of grinding any of the inner and outer peripheral surfaces of the cylindrical magnet material, it is possible to obtain a thin ring-shaped magnet having a highly accurate inner and outer diameters and a high roundness, which cannot be obtained conventionally. As a result, it is possible to set and realize a minimum magnetic gap of the motor, and it is possible to manufacture a high-torque, high-rotation type motor.

On the other hand, if the cylindrical magnet materials 1 and 2 are unpainted, the adhered surfaces are painted when they are adhered to the support member composed of the inner and outer cases. By forming a resin on the surface, a protective film can be formed on the entire surface of the magnet material.

The case where the cylindrical magnet materials 1 and 2 are not coated with resin has been described. However, even if the cylindrical magnet materials are coated with resin in advance, the above-described effects and effects on accuracy are the same. In particular, when the cutting resin of the present invention is applied,
Cutting workability and processing accuracy are greatly improved.

The cylindrical magnet material previously coated with resin is adhered to the above-mentioned support member composed of the inner and outer cases, and the inner or outer peripheral surface of the material is ground to form a ring-shaped magnet having a required inner or outer diameter. And the resin on the processed surface is gone,
After processing, a protective film can be formed on the entire surface of the magnet material by forming a resin film on the processed surface of the material.

Until now, the cylindrical magnet material has been adjusted to the desired magnet height h.
(Axial length) has been described. Hereinafter, a case of a long cylindrical magnet material will be described. As shown in FIG. 3A, the elongate cylindrical magnet material 3 has a wall thickness in the outer diameter direction that is set to be much larger than a target dimension, so that the magnetic powder can be filled into the molding space of a long mold in the axial direction. Improve
Further, the orientation in a magnetic field can be improved.

As shown in FIG. 3B, a long and thin cylindrical case 30 is prepared separately. When the yoke is also used, the cylindrical case 30 is made of a magnetic material having a required thickness. On the other hand, when the magnet material is to be easily handled or the strength is to be improved, or when the rotor is further provided for each case. For example, a thin deep-drawn aluminum case having a thickness of about 0.1 mm can be employed.

The outer diameter D2 (inner diameter D3) of the cylindrical magnet material 3 is set to be equal to the inner diameter D2 (outer diameter D1) of the cylindrical case 30, and as shown in FIG. Is inserted into the case 30 and fixed by adhesion. Then, the cylindrical case 30 containing the cylindrical magnet material 3 is cut into a plurality of portions at the broken lines shown in the drawing to produce a cylindrical magnet material having a required height. After cutting into a plurality of pieces in a direction perpendicular to the axial direction of the cylindrical case 30, each cylindrical magnet material 4 is chucked together with the cylindrical case 31, and the inner peripheral surface thereof is ground to form a required inner diameter D 4. Thus, the desired thin ring-shaped magnet 5 can be obtained.

Further, the whole of the long cylindrical case 30 shown in FIG. 3C is chucked by a grinding device, and the inner peripheral surface of the cylindrical magnet material 3 is ground first to obtain a required inner diameter D4. Cut into a plurality of pieces in the direction orthogonal to the axial direction of the case 30,
The target thin ring-shaped magnet 5 shown in FIG. 3D can be obtained.

In order to obtain a required inner diameter D4 by grinding based on the outer diameter D1 of the long or short cylindrical cases 30, 31 which have been formed and processed with high dimensional accuracy, the desired high precision. A thin ring-shaped magnet 5 having inner and outer diameters can be obtained. Moreover, since the thin ring-shaped magnet 5 has the cylindrical case 31 adhered and fixed to the outer peripheral surface, it is excellent in strength and easy to handle.

If the cylindrical magnet material 3 is unpainted, the adhesive surface is coated when the cylindrical magnet material 3 is bonded to the support member composed of the long cylindrical case 30, and all the exposed surfaces including the processed surface are further cut and cut. By forming a resin on the surface, a protective film can be formed on the entire surface of the magnet material.

Even if the cylindrical magnet material 3 is coated with a resin in advance, the above-described effects and effects on accuracy are the same. In particular, when the cutting resin of the present invention is applied, cutting workability and processing accuracy are greatly improved.

The cylindrical magnet material 3 previously coated with resin
Is adhered to the support member formed of the cylindrical case 30, and the inner peripheral surface of the raw material is ground to be processed into a ring-shaped magnet having a required inner diameter or outer diameter, and the resin on the processed surface is lost. By forming a resin film on the processed surface of the material, a protective film can be formed on the entire surface of the magnet material.

1A, 2A, and 3A, the mechanical strength is improved in any case when the entire surface is coated with the cutting resin of the present invention, for example. In addition to being easy to handle, dirt and rust can be prevented until the required high precision processing is performed,
Excellent as a material for ring magnets.

The cylindrical magnet blanks 1, 2, 3 shown in FIGS. 1C, 2C and 3C are adhered and fixed, for example, to a support member made of various forms of case with the cutting resin of the present invention, and the exposed surface is formed. When coated, the mechanical strength is further improved in each case, so handling is particularly easy, and dirt and rust can be prevented until the required high precision processing is performed. It is excellent as a material for use.

The ring-shaped magnet material sliced from the cylindrical magnet material 3 shown in FIG. 3C has been previously bonded and coated on the exposed surface with the cutting resin of the present invention.
Since the mechanical strength is improved, handling becomes particularly easy, and dirt and rust can be prevented until required high-precision processing is performed.

The ring-shaped magnet 5 shown in FIG. 3D is also a material for a ring-shaped magnet until it is incorporated into a magnetic circuit. By doing so, the mechanical strength is improved and handling becomes easier, and in particular, dirt, rust and the like can be prevented for many years even after the assembling.

In the fixing step involving the application of the adhesive or the film forming step of the resin, the adhesive or the resin may be applied to the outer peripheral surface or the inner peripheral surface of the cylindrical magnet material by any known method. . However, the following method is preferable for forming an adhesive or a resin into a thin film with a uniform thickness in units of μm.

For example, when a coating film is provided on the inner peripheral surface of the ring-shaped magnet 5 shown in FIG. 3D, a cylindrical or column-shaped coating member facing the inner peripheral surface with a required small gap is used.
Here, it is assumed that the cylindrical coating member is disposed in the lifting device, and the ring-shaped magnet is fixed to the chuck device and disposed on the same axis center line above the lifting device.

First, an appropriate amount of, for example, an ultrafine particle-containing liquid phase material is supplied to the outer peripheral surface from the inside of the cylindrical coating member, and the inner surface of the ring-shaped magnet fixed to the chuck device is provided. The liquid phase material is supplied to a required gap between the cylindrical application member and the ring-shaped magnet that have risen and entered, and when the cylindrical application member descends, the film of the liquid phase material has a uniform thickness on the inner peripheral surface of the ring-shaped magnet. As thinly as possible.

The movement relationship between the ring-shaped magnet and the cylindrical coating member is as follows. In addition to the movement of the cylindrical coating member as described above, even when the ring-shaped magnet moves, both move close to and away from each other. It is preferable that the relative movement between the two is performed, and the above-mentioned conditions are appropriately selected by setting the gap between the cylindrical coating member and the ring-shaped magnet, the moving speed, the relative time, the viscosity of the resin, and the like. As described above, the liquid phase film is formed into a thin film and a uniform thickness.

Therefore, when applied to the outer peripheral surface of the cylindrical magnet material, it has an inner diameter larger by the required gap than the magnet material so that the outer peripheral surface of the magnet material can be coaxially relative to the outer peripheral surface via the required gap. By using a cylindrical coating member, it is possible to supply an adhesive or a resin into the required gap, and the relative movement of one or both of the cylindrical magnet material and the cylindrical coating member moving on the same axial center is achieved. The resin in the gap is uniformly applied to the outer peripheral surface of the magnet material.

[0074]

EXAMPLE 1 As a cylindrical magnet material shown in FIG. 1A, an R-Fe-B-based magnet material and an Sm-Co-based magnet material were used and molded in a magnetic field to have an outer diameter of 28 mm, an inner diameter of 20 mm, and a height of 4 mm. It was produced by firing to dimensions. Thereafter, a cutting resin was applied to the entire surface of the cylindrical magnet material. The case shown in FIG. 1B was manufactured by cutting from an aluminum bar.

The cutting resin is prepared by kneading a silicon-modified acrylic resin and SiO ₂ ultrafine powder having an average particle diameter of 7 nm in a ratio of 5: 1 and homogeneously so that the ultrafine powder cannot be centrifuged. This resin solution was diluted with a solvent for coating before use.

After the cylindrical magnet material is bonded and fixed at a predetermined position on the inner peripheral surface of the case with a cutting resin, the case itself is chucked by a cutting device to cut the inner peripheral surface of the cylindrical magnet material and crack into the magnet material. Without causing any damage such as chipping
It could be processed into a ring-shaped magnet having an inner diameter of 25.6 mm and a thickness of 1.2 mm.

Example 2 R-Fe-B-based magnet material and Sm-Co-based magnet material were used as the cylindrical magnet material shown in FIG. 3A, and were molded in a magnetic field to have an outer diameter of 28 mm, an inner diameter of 15 mm, and a height of 50 mm. And baked. Thereafter, a cutting resin was applied to the entire surface of the cylindrical magnet material. The case shown in FIG. 3B was manufactured by deep drawing from an aluminum material so as to have a wall thickness of 0.1 mm.

A cylindrical magnet material was inserted into an aluminum case and fixed with a cutting resin. Thereafter, the case itself was chucked by a cutting device to cut the inner peripheral surface of the cylindrical magnet material, whereby the cylindrical magnet material could be processed into a ring-shaped magnet having an inner diameter of 25.6 mm and a wall thickness of 1.2 mm. Further, each case was sliced and processed into ten ring-shaped magnets without causing any damage such as cracking or chipping of the magnet material.

Further, after inserting the cylindrical magnet material into the aluminum case and fixing it with the cutting resin, the case was first sliced into 10 ring-shaped magnet materials. Next, the case itself is chucked by a cutting device to cut the inner peripheral surface of the cylindrical magnet material, without causing any damage such as cracking or chipping to the magnet material, the inner diameter is 25.6 mm, and the wall thickness is 1.2 mm. Could be processed into a ring-shaped magnet.

Example 3 As ultrafine particles, 7 to 30 nm of SiO ₂ alone, 7 to 30 nm
30 nm of SiO ₂ and 13 to 60 nm of Al ₂ O ₃ are:
The mixture was kneaded by a ball mill so that the ratio was 1 to 10%, 20%, and 30% in commercially available liquid paraffin for cosmetics. Further, a liquid phase material containing ultrafine particles of SiO ₂ alone kneaded with MMA was kneaded with the liquid paraffin by a ball mill. Each of the obtained colorless and transparent ultrafine particle-containing liquid phase bodies was centrifuged, but the ultrafine particle powder could not be separated from the oil.

Ultrafine particle-containing liquid phase bodies were kneaded in various amounts with commercially available Nd-B-Fe isotropic bonded magnet powder together with 3% of an epoxy resin for a binder to prepare a magnet powder.
A cylindrical molded body was produced by press-fitting into a mold, and this was heated and solidified to produce a cylindrical bonded magnet. The liquid paraffin volatilized at the heating temperature at the time of solidification, and only ultrafine particles were uniformly dispersed and introduced into the magnet.

Tests for cracks and chips at the ends, which are problematic for bonded magnets, showed that as the amount of ultrafine particles introduced into the magnet increased, cracks and chips were less likely to occur and the strength was improved. . In addition, it was confirmed that the electric resistance of the magnet was increased and eddy current was hardly generated.

Further, a liquid phase material containing ultra-fine particles made of the liquid paraffin is kneaded in various amounts with the alloy powder for a ferrite magnet to produce a magnet powder, which is inserted into a mold and compressed to form a ring-shaped compact. And a molded body was sintered to produce a ring-shaped magnet.

The production of a ring-shaped molded article by dry molding is as follows.
Since the ultrafine particle-containing liquid phase was mainly composed of liquid paraffin, smooth and high-density loading could be performed. The occurrence of cracks and chipping at the edge of the obtained molded article was significantly reduced as compared with the related art.

During the heating process during sintering, the liquid paraffin volatilized, and only ultrafine particles were uniformly dispersed and introduced into the magnet. In addition, the degree of a slight reduction phenomenon after sintering, which has conventionally been inevitable, has been reduced to 1/3 to 1/2, and a sintered body having good dimensional accuracy has been obtained. When these cylindrical magnet materials were used in Examples 1 and 2, the dimensional accuracy was high and the strength was high, so that the handling was good, and there was no processing defect, and the yield was significantly improved.

A commercially available silica content of 10 to 20
%, PH 7.5 to 9.5, viscosity 5 to 15 cps using various colloidal silicas, dipping, spraying,
These impregnations were performed by applying with an electrostatic coating gun and spraying steam. It was confirmed that the hardness, strength, heat resistance, and disaster resistance of the material after impregnation were significantly improved as compared with those without impregnation.

[0087]

According to the present invention, 1) the thickness can be made thicker than the desired thickness, so that the mechanical strength of the sintered cylindrical magnet material can be greatly improved and the grinding process can be facilitated. Because it can be made thicker, it significantly improves the orientation of the magnetic powder of the cylindrical magnet material during molding in a magnetic field, and it can be manufactured with good yield. 3) The inner peripheral surface of a highly-accurately processed outer case or yoke incorporated in the motor. That the required magnetic gap between the magnet inner diameter and the fixed side coil can be set with high precision. 4) Even if the magnet contains a rare earth element that requires a surface protective film, it must be mounted on the outer case or yoke. The film can be easily formed by coating with a small-diameter roll or a cylindrical coating device after bonding and after processing, and the protective film process can be simplified and reduced.

The adhesive and paint containing fine silica according to the present invention have the following advantages: 1) excellent adhesion to a magnet material and high surface protection ability; 2) remarkable improvement in grinding property by fine silica; Excellent in adhesiveness and adhesion strength to resin support members and the like.

Further, by forming the cutting resin on the entire cylindrical magnet material in advance, 1) the adhesion to the magnet material is excellent and the surface protection ability is high, and 2) the sintered cylindrical magnet material is It is possible to greatly improve the mechanical strength,
3) The grinding property is remarkably improved by the fine silica. 4) The grinding property is remarkably improved by using together with the above-mentioned means for fixing to the inner peripheral surface or the outer peripheral surface of the motor case, and the mass productivity and the yield are improved. The ring-shaped magnet can be manufactured. 5) The resin liquid has an advantage that it has excellent adhesion to the surface of the magnet material after cutting and has high surface protection ability.

The cylindrical magnet material on which the cutting resin according to the present invention is formed in advance has a high mechanical strength and is easy to handle, and the cylindrical magnet material attached to the support member is easier to handle. It is easy and easy to store and transfer to the subsequent process, and has excellent protection ability of the magnet itself.

The cylindrical magnet material produced by kneading the ultrafine particle-containing liquid phase material according to the present invention has higher mechanical strength and is easier to handle, and has excellent dimensional accuracy. Processing accuracy is further improved. Furthermore, by impregnating the ultrafine particle-containing liquid phase body before cutting, the surface strength is improved and cutting accuracy is further improved, and by impregnating from the surface layer after cutting, the strength of the magnet is greatly improved. .

[Brief description of the drawings]

FIGS. 1A to 1D are perspective explanatory views showing steps of manufacturing a ring-shaped magnet according to the present invention.

FIGS. 2A to 2D are perspective explanatory views showing steps of manufacturing a ring-shaped magnet according to the present invention.

FIGS. 3A to 3D are perspective explanatory views showing steps of manufacturing a ring-shaped magnet according to the present invention.

[Explanation of symbols]

 1, 2, 3, 4 Cylindrical magnet material 5 Thin ring-shaped magnet 10 Case 11, 12 Cap portion 20 Inner case 21 Large diameter portion 22 Small diameter portion 30, 31 Cylindrical case

Claims (28)

[Claims] 1. A step of fixing an outer peripheral surface or an inner peripheral surface of a cylindrical magnet material to an inner peripheral surface or an outer peripheral surface of a support member, and grinding the inner peripheral surface or the outer peripheral surface of the raw material to a required inner diameter or outer diameter. A method for producing a ring-shaped magnet, comprising a step of processing into a ring-shaped magnet having a diameter. 2. The method for manufacturing a ring-shaped magnet according to claim 1, further comprising a step of cutting the raw material into a plurality of pieces together with the support member in a direction perpendicular to the axial direction after fixing the material to the support member. 3. The method for manufacturing a ring-shaped magnet according to claim 1, wherein a step of forming a resin film on an exposed surface of the material is added after the processing step. 4. The method for producing a ring-shaped magnet according to claim 1, wherein the cylindrical magnet material is previously coated with a resin. 5. The method for manufacturing a ring-shaped magnet according to claim 1, further comprising a step of forming a film of a resin on an exposed surface of the material after fixing the material to the support member. 6. A process for obtaining a cylindrical magnet material in advance includes forming a colloidal silica or an ultrafine particle-containing liquid phase material in which ultrafine particles are mechanically and uniformly dispersed in a resin solution or liquid paraffin into a cylindrical magnet material. The method for producing a ring-shaped magnet according to any one of claims 1 to 5, further comprising a step of kneading the powder for body use. 7. Before or after the processing step, the ultrafine particle-containing liquid phase body obtained by uniformly dispersing the ultrafine particle powder in a colloidal silica or a resin liquid or liquid paraffin so as to be unable to be mechanically centrifuged is exposed to the material. The method for producing a ring-shaped magnet according to any one of claims 1 to 6, further comprising a step of impregnating from a surface layer on the surface. 8. The method for producing a ring-shaped magnet according to claim 7, wherein the impregnation of the ultrafine particle-containing liquid phase body is performed in an atmosphere containing steam. 9. In a fixing step involving application of an adhesive or a film forming step of a resin, a cylindrical or column-shaped coating member opposed to an outer peripheral surface or an inner peripheral surface of a cylindrical magnet material via a required gap is used. Supplying an adhesive or resin into the required gap,
9. A step of applying an adhesive or resin to an outer peripheral surface or an inner peripheral surface of the cylindrical magnet material by relative movement of one or both of the cylindrical magnet material and the application member on the same axis. The method for producing a ring-shaped magnet according to any one of the above. 10. The method for manufacturing a ring-shaped magnet according to claim 1, wherein the support member is any one of a metal, a resin material, and a resin-impregnated paper. 11. The method for manufacturing a ring-shaped magnet according to claim 1, wherein the support member is cylindrical or columnar, and the processing is performed with reference to a center axis of the member. 12. The method for manufacturing a ring-shaped magnet according to claim 11, wherein the support member is an outer case or an inner case for a motor or a magnetic circuit member. 13. The method for producing a ring-shaped magnet according to claim 1, wherein a cutting resin is used as an adhesive or a film-forming resin in the fixing step. 14. The method for producing a ring-shaped magnet according to claim 13, wherein the cutting resin is a resin containing fine silica in at least one of a urethane resin and an acrylic resin. 15. The ultrafine particles of the ultrafine particle-containing liquid phase body have at least one of a spherical form, a porous form, and a fibrous form, have an average particle diameter of 100 nm or less, and have an average molecular weight (formula weight). 10. The method for producing a ring-shaped magnet according to any one of claims 7 to 9, wherein the number is from 30 to 150. 16. The ultrafine particles are made of SiO ₂ , Al ₂ O ₃ , Zr
_{O 2, SiC, SiN, AlN} , ZrN, method for producing a ring-shaped magnet according to any one of claims 7 to 9 at least one of TiN. 17. The method for producing a ring-shaped magnet according to claim 1, wherein the magnet material is a rare earth-containing magnet alloy. 18. The method for producing a ring-shaped magnet according to claim 1, wherein the magnet material is for a radial anisotropic magnet. 19. A ring-shaped magnet material made of a cylindrical magnet material having a cutting resin film formed on the surface thereof. 20. A ring-shaped magnet material in which a cylindrical magnet material having a required thickness is bonded and fixed to an inner peripheral surface or an outer peripheral surface of a support member at an outer peripheral portion or an inner peripheral surface of the magnet material. 21. The ring-shaped magnet material according to claim 20, wherein a cutting resin is formed on the exposed surface. 22. The ring-shaped magnet material according to claim 19, wherein the cutting resin is a resin containing fine silica in at least one of a urethane resin and an acrylic resin. 23. The ring-shaped magnet material according to claim 19, wherein the magnet material is a rare earth-containing magnet alloy. 24. The ring-shaped magnet material according to claim 19, wherein the magnet material is for a radial anisotropic magnet. 25. A cutting resin containing fine silica in at least one of a urethane resin and an acrylic resin. 26. The cutting resin according to claim 22, wherein the fine silica has an average particle size of 500 nm or less. 27. The cutting resin according to claim 22, wherein the fine silica has an average particle size of 100 nm or less. 28. The cutting resin according to claim 22, wherein the average particle size of the fine silica is 50 nm or less.