JPS63119509A - Resin magnet structure - Google Patents

Abstract

PURPOSE:To provide a small size, light weight structure and improvement of the assemblability while maintaining a high performance by integrally molding the composite material of a magnet material and a binder with a support member. CONSTITUTION:In the resin magnet structure for use with a permanent magnet rotor which is used for controlling or driving a computer peripheral equipment such as printer, a support member 1 consisting of a molded article of a thermally polymerizable resin molding material or the like is placed in a metallic cavity. After a composite material 2 of a magnet material and a binder is compressed, the binder is polymerized and cured, thereby providing integration. With this, a small size and high performance product can be provided while maintaining the characteristics controlled by a resin magnet.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is for controlling computer peripherals, printers, etc.
The present invention relates to a resin magnet structure used in a so-called permanent magnet rotor used for driving purposes.

More specifically, the present invention relates to a resin magnet structure in which a support member is integrally molded with a composite of a Fe-B-R type (I1, R is Nd or/and Pr) magnet material and a binder.

2. Description of the Related Art The resin magnet of the resin magnet structure to which the present invention is applied usually has an annular shape such as a ring shape, a p:I cylindrical shape, or a C shape, and one support member has a ring shape 9 cylindrical shape 2 It is cylindrical.

RCo5. R(Co, Cu, Fe, M)n (where R is S
Rare earth elements such as m, Ce, M is a combination of one or more elements belonging to group ■, group V, group ■, group ■ of the periodic table, n is generally an integer from 5 to 9), etc. The rare earth cobalt sintered magnet exemplified by is formed into an annular shape, and it is extremely difficult to make the magnetic anisotropy in the radial direction of the shape. The main reason for this is that there is a difference in expansion coefficient due to anisotropy during the sintering process, and especially in the case of thin-walled annular magnets, isotropy is the only solution. For this reason, it should be 20 to 30
The advanced magnetic performance developed by M G Oe is also FI M G
This decreases to about Oe. Furthermore, in the case of permanent magnet rotors, which require a high degree of dimensional accuracy, grinding is required after sintering, which causes water retention, and since the main components are Sm and Co, there is a problem in terms of economy and performance. lack of balance. Moreover, since sintered magnets are mechanically fragile, a portion of them is easily detached, scattered, or transferred to other members. This has a serious effect on, for example, maintaining the function and ensuring reliability of the permanent magnet rotor.

On the other hand, in the case of rare earth cobalt resin magnets, the matrix resin absorbs the difference in expansion coefficient of the rare earth cobalt, which is magnetically anisotropic in the radial direction, so that a magnet with magnetic anisotropy in the radial direction can be obtained. For example, when an injection molded rare earth cobalt resin magnet is made magnetically anisotropic in the axial direction, a magnet with a maximum energy product of 8 to 10 MGOe can be easily obtained. Moreover, the density is approximately 30% compared to fired crystals.
It can be said that it is more preferable as an annular magnet, especially a thin annular magnet, than a sintered magnet because it reduces the weight, ensures a high degree of dimensional accuracy, and improves mechanical fragility.

Problems to be Solved by the Invention However, even the above-mentioned rare earth cobalt resin magnets have the disadvantage that they cannot sufficiently reduce the size and weight of annular magnets. The reason is explained below.

Generally, as a means to make rare earth cobalt magnetically anisotropic in the radial direction, for example, as described in Japanese Patent Application Laid-Open No. 57-170501, a magnetic yoke and a non-magnetic yoke are combined surrounding a cavity, and the outside A mold in which a magnetizing coil is arranged is used, or a mold in which a magnetizing coil is embedded in the outer periphery of the cavity is used. In this method, a high voltage, large current type power source is used to generate a predetermined magnetic field strength within the cavity, and the magnetomotive force is increased. However, in order to effectively focus the magnetic flux excited by the magnetizing coil from the outer periphery of the mold into the cavity using the yoke, the magnetic path length must be made long.Especially in the case of a small annular magnet, the magnetomotive force is considerably large. A portion of the magnetic flux is consumed as leakage magnetic flux. Therefore, magnetic anisotropy in the radial direction may not be achieved sufficiently depending on the shape of the magnet.
Qualitatively, it cannot be said that in the case of a permanent magnet rotor, which is used as a practical example of the present invention, it is not possible to maintain high performance and to sufficiently cope with miniaturization or weight reduction.

On the other hand, the annular magnet used in the above-mentioned permanent magnet rotor is preferably a thin annular shape due to the torque/inertia ratio, and in the case of multi-phase excitation, it is not a single magnet, but only the part corresponding to the excitation side. A so-called split magnet structure in which thin-walled annular magnets are provided is desirable. In the case of such a divided magnet structure, rather than fixing the shaft directly to the annular magnet, it is often the case that the divided annular magnet and the shaft are fixed with a support member interposed between them. Generally, the annular magnets are attached by mechanical fitting or by filling adhesive from the outside.

Therefore, if mechanical fitting is performed, there is a risk of damage to the annular magnet (and in the case of adhesive (4), there is a need for a gap for the adhesive to flow between the supporting member and the annular magnet). There are problems with bonding strength, dimensional accuracy, and workability, and improvements in assembleability have been desired from these points of view.

The present invention relates to a resin magnet structure used in a permanent magnet rotor that is desired to be smaller, lighter, and easier to assemble while maintaining the above-mentioned high performance, and maintains the performance dominated by the resin magnet. At the same time, we aim to provide a resin magnet structure that is compatible with miniaturization and UT and is easy to assemble. It is something.

Means for Solving the Problems The present invention relates to a resin magnet structure used in a permanent magnet rotor aimed at miniaturization, in which the supporting member is integrally molded from a composite of a magnet material and a binder. It is something.

Action.

A supporting member made of a molded article of a thermopolymerizable resin molding material or the like is installed in the mold cavity, the composite of the magnet material and the binder is compressed, and then the binder is polymerized and hardened to be integrated. This makes it possible to achieve smaller size and higher performance while maintaining the characteristics dominated by the resin magnet.

Example The present invention will now be described with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an example of the resin magnet structure referred to in the present invention. In the figure, reference numeral 1 denotes a support member, and an engaging portion 1' with a resin magnet is provided on the outer peripheral portion.

2 is a resin magnet structure integrated by compression molding a composite of a magnet material and a binder on the outer periphery of the support member 1, and 2' is a resin magnet. Reference numeral 3 denotes a permanent magnet rotor in which two resin magnet structures 2, each of which is made up of a support member] and a resin magnet 2', are arranged side by side and assembled around a shaft 4. As illustrated, the resin magnet 2' can be provided at any location facing the excitation coil. Such a permanent magnet rotor 3 is put into practical use as a so-called PM type pulse motor shown in a perspective view as shown in FIG. 2 by, for example, magnetizing the outer peripheral surface of a resin magnet with multiple poles. However, in the figure, 1 is a support member according to the present invention, 2 is a resin magnet structure formed by integrating the support member 1 and a resin magnet 2', and 3 is a permanent magnet in which the resin magnet structure 2 is assembled with a shaft 4. It is a rotor. The field portion includes outer yokes 6a and 6b, two inner yokes 5 joined back to back, and an excitation coil 7a housed between them.

7b. In such an ffPM type pulse motor, the permanent magnet rotor is displaced by one step angle by the magnetomotive force of the excitation coil corresponding to one pulse current.

Next, the support member 1 referred to in the present invention is a molded article of a thermopolymerizable resin molding material containing at least 65% by volume of an inorganic filler. Here, thermopolymerizable resin molding materials include epoxy resin, unsaturated polyester resin, phenol resin, silicone resin, etc., alumina, aluminum hydroxide, silica, fused silica glass, zirconium silicate, and calcium carbonate.

It is a multi-component composite material consisting of fillers such as glass fibers, various lubricants such as fatty acid metal salts, fatty acid esters, fatty acid amide, and various additives added as necessary, such as pigments. In particular, in the present invention, the content of the inorganic filler is 65% by volume or more. The reason for this is that the support member 1 is capable of resisting mechanical pressure when the composite of the magnet material and the binder is compressed, and is necessary to ensure the reliability of the resin magnet structure. Figure 3 shows the flexural modulus, thermal expansion coefficient, and thermal conductivity of a molding material using fused silica glass as an inorganic filler and epoxy resin as a thermopolymerizable resin, relative to the volume percent of the original inorganic filler. FIG. When the inorganic filler exceeds 65% by volume, the elastic modulus becomes significantly high,
Thermal expansion is also
X1. Since it is almost the same as O''C'), it is a region that can withstand the mechanical pressure when the composite of the magnet material and the binder is compressed and can ensure the reliability of the resin magnet structure.

Next, the magnet material referred to in the present invention is a liquid quenched Fe-R-B system (where R is Nd or/and Pr). For example, this has a standard atomic composition Fee+.

It is represented by Nd+3.8e and was manufactured by a liquid quenching method. For example, Fe-R-8 molten alloy is
Thick-walled 1 obtained by crushing quenched ribbon pieces through an orifice and rolls in a continuous chamber in an r gas atmosphere
It refers to plate-shaped particles with a length of 0 to 30 μm in the longitudinal direction of several tens to hundreds of μm. These particles have extremely fine Fe-R-
It has a microstructure dotted with B ternary magnets and is magnetically isotropic. Such liquid quenched Fe
-R-8 is made into an amorphous state when obtaining a quenched ribbon piece, and then heated to a temperature higher than the crystallization temperature to form Fe-
It does not matter whether the production history is R in which the R-B ternary magnet phase is precipitated or the production history is in which the final microstructure is formed directly during quenching. Furthermore, liquid quenched Fe-
Si, A1. Mo, Co, Zr, Pd, Y.

There is no problem even if other elements such as Tb are mixed.

In particular, in the Fe-R-B system, it is possible to improve the thermal stability of the resin magnet structure by replacing a part of Fe with one or more of Co and heavy rare earth elements. In some cases, it can be an effective means to ensure environmental friendliness.

Next, the binder referred to in the present invention consists of a polymer having at least an active hydrogen in its molecular chain that can react with an isocyanate group and an isocyanate regenerant.

First, in a polymer having an active hydrogen that can react with an isocyanate group in the molecule, the active hydrogen-containing group is
For example -OH, -COOH, -NHCO-.

-NHCOO+, -NHCONH-, -NH2゜-8H
, active methylene, etc., and any polymer may be used as long as it has these in its molecular chain. In particular, as the group having active hydrogen, those having -OH and -NHCO- are preferable.

For example, polyester that has hydroxyl groups in its molecular chain.

Examples include polyether ester, polyether, polyester imide, and epoxy resin, and there are also those having an amide group such as polyester amide imide, polyamide, polyamide imide, and polyurethane. Examples of polyethers having active hydrogens in their molecular chains that can react with isocyanates include those obtained from bisphenols and epichlorohydrin or substituted epichlorohydrin, and are represented by the following general formula.

Here, R1 is represented by -CpH2p (p is an integer) such as -8-, -〇-, -8o-, -3O2- or -CH2-CH2CH2-, -C(CH3)2-, and R
2 is -H or -CqH2q such as -CH3, -C2H5
+1 (q is an integer). Among these, R1 is (CH3)2- and R2 is -H
It is a polymer obtained by the condensation of bisphenol A and epichlorohydrin. Note that these may also be copolymers. In addition, one isocyanate regenerated product is an isocyanate compound such as P-phenylene diisocyanate, m-phenylene diisocyanate, 2
・4-tolylene diisocyanate, 2.6-tolylene diisocyanate.

Adding an active hydrogen compound to an isocyanate compound such as P-P' diphenylene diisocyanate, P-P' diphenylmethane diisocyanate, P-P' diphenyl ether diisocyanate, P-P' diphenylsulfone diisocyanate, This is a regenerated isocyanate compound. Furthermore, it refers to a regenerated product obtained by adding an active hydrogen compound to the isocyanate group of an amide or imide ring-introduced isocyanate compound obtained by reacting the isocyanate compound with tricarboxylic anhydride, tetracarboxylic anhydride, or the like. However, active hydrogen compounds that add to isocyanate groups to form regenerated products include amines, acidic sulfites, tertiary alcohols, lactams, enols, oximes, mercaptans, α-
Pyrrolidone, phenol, m-cresol, xylenol, etc.

The ratio of (isocyanate groups/active hydrogen) of the above-mentioned mixture of the polymer having active hydrogen capable of reacting with isocyanate groups in the molecule and the isocyanate regenerated product is preferably 0.6 to 1.0. For example, if it is lower than 0.6, the crosslinking density will decrease and the thermal stability of the resin magnet will tend to decrease, and if it exceeds 1.0, relatively low molecular weight isocyanate regenerants will remain in the binder as unreacted substances. This is because, for example, the thermal stability, dimensional accuracy, and environmental resistance of the resin magnet may deteriorate.

Hereinafter, the present invention will be specifically explained with reference to Examples.

However, the present invention is not limited to the examples.

As the support member 1, molded articles made of thermopolymerizable resin molding materials containing different inorganic fillers were prepared. However, the shape of the support member 1 has an engaging portion 1' as shown in FIG. 1, and has an outer diameter of 5.5+n* and an inner diameter of 3.0 m.

The length is 5.9m++. In addition, fused silica glass is used as the inorganic filler, and its content is 55.65, 75°80.
% by volume, and one thermopolymerizable resin has a secondary transition point of 150.
~160°C epoxy resin was used.

The magnet material is Ndo, 13 (p60.93. Bo, 0
7) Liquid quenched Fe-B-R particles with a molecular weight of 0.87 were used, and bisphenol A with a molecular weight of about 2.900 was used as a binder.
A polyether obtained by the condensation of Ebichlorolihydrin and a regenerated P-P'-diphenylmethane diisocyanate (ratio of isocyanate groups/active hydrogen is 1.0) were used. In addition, the composite of magnet material and binder is
It was bound at 7% by weight.

Inserting the support member, which is a molded product of a thermopolymerizable resin molding material different from the above-mentioned inorganic filler-containing molding material, into the mold cavity,
4.5 to 5.8 g/c- of a composite of magnet material and binder
compressed to a density of

Thereafter, the binder was polymerized and cured to obtain a resin magnet structure as shown in FIG. However, the outer diameter of the resin magnet 2' shown in FIG. 2 is 8 mm. If such a resin magnet structure cannot withstand mechanical pressure when the composite of the magnet material and the binder is compressed, annular cracks will occur in the supporting member. However, when the inorganic filler is 65% by volume or more, this does not occur, and the dimensional change of the supporting member is only 5μ-
It was below.

Next, a resin magnet structure using a support member made of a molded article of a thermopolymerizable resin molding material containing 65% by volume or more of an inorganic filler is heated to 120°C, and then immediately heated to -30°C. Although the thermal shock of immersion was repeated 20 times, no cracks or dimensional changes were observed in the support member, resin magnet, etc. Furthermore, when looking at the deflection of the outer periphery of the resin magnet based on the inner diameter of the support member, a high degree of dimensional accuracy within 10 μm was maintained and ensured.

In addition, after leaving the composite of the magnet material and the binder at 40°C and -electronic relative humidity for an arbitrary period of time, the resin magnet structure integrated with the supporting member was magnetized with 10 poles on the outer circumference, and the total magnetic flux was It was measured. Table 1 is a characteristic table showing the storage stability of the composite in terms of the total magnetic flux of the resin magnet structure.

As is clear from Table 1, the storage stability of the composite of the magnet material and binder according to the present invention is extremely excellent, which is advantageous for maintaining and ensuring the quality of the resin magnet structure. is obvious.

Next, as shown in FIG. 1, two resin magnet structures were axially opposed to each other, assembled by the shaft, and further magnetized with 10 outer circumferential poles to form a permanent magnet rotor.

On the other hand, magnetic material binding Sm ((:00, 88 B,
(: uO, I 01 .

FeO, 2+4. By axial magnetic anisotropy obtained from rare earth cobalt and 12-polyamide shown in [Z jo, ol]) 7, an injection molding type resin magnet material of 9 M G Oe is radially heated under a repulsive magnetomotive force of 45,0 OOAT. It was made into a magnetically anisotropic magnet.

In addition, a 13MGOe compression molded resin magnet material was made into a radial magnetic anisotropy magnet under the same magnetic field conditions by axial magnetic anisotropy obtained from the rare earth cobalt and liquid epoxy resin. However, all of them have dimensions of an outer diameter of 8 +w, an inner diameter of 5.5 m, and a height of 4 -, and by inserting them into a support member made of AQ and gluing them, a permanent magnet rotor as shown in Fig. 4 was created. . However, in the figure, 8 is a radial magnetic anisotropic resin magnet, 9 is a support member, 10 is an adhesive material, and the outer periphery 1
Zero pole magnetization.

A permanent magnet obtained by adhering a rare earth cobalt resin magnet with radial magnetic anisotropy to a supporting member has a diameter of 2 to 12 μm on the outer circumference of the resin magnet based on the axis of the permanent magnet rotor obtained from the resin magnet structure of the example of the present invention. The outer peripheral runout of the resin magnet with respect to the axis of the magnet rotor is as large as 8 to 23 μ-.

Next, FIG. 5 shows the relationship between the pulse rate and pullout torque when the permanent magnet rotor is a PM type pulse motor as shown in FIG. 2. However, PPS in the figure is Pu1s
e Per 5econd, and Example 1 of the present invention. ，
2.3 is a resin magnet structure in which the density of the resin magnet portion is different, and the values are also listed. Further, Target Example 1 is a permanent magnet rotor obtained from a resin magnet structure having the same configuration as the example of the present invention, but the density of the resin magnet portion is 4.6 g/cd. Comparative Examples 1 and 2 used injection molded and compression molded rare earth cobalt resin magnets with excellent radial magnetic anisotropy. As is clear from the figure, Examples 1 to 3 of the present invention exhibit higher torque than the permanent magnet rotor of Comparative Example 2, which is made of compression-molded rare earth cobalt resin magnets. Also, the density of the resin magnet is about 15~
Since it is 25% lower, the torque/inertia ratio is excellent. Furthermore, as in Target Example 1, if the density of the resin magnet portion of the resin magnet structure according to the present invention is less than 5.0 g/c+J, high torque cannot be obtained. Compared to a permanent magnet rotor made of cobalt resin magnets, the torque is higher, and since the rotor is at the end, the maximum response frequency extends to a high pulse rate range.

Effects of the Invention As described above, the present invention applies to a resin magnet structure used in a permanent magnet rotor that is desired to be smaller and have higher performance, and can be made smaller and more efficient while maintaining the characteristics controlled by the resin magnet. Since it has both the ability to respond to high performance and the ease of assembling, it is useful in fields such as PM type pulse motors.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an annular resin magnet structure, Fig. 2 is a perspective view of a PM type pulse motor based on an example of the present invention, and Fig. 3 is a support member containing an inorganic filler, bending elastic modulus, and line FIG. 4 is a perspective view of a conventional PM type pulse motor, and FIG. 5 is a characteristic diagram showing the relationship between pulse rate 2 and pull-out torque. 1...Supporting member, 1'...Engaging portion, 2
... Resin magnet structure, 2' ... Resin magnet, 3 ... Permanent magnet rotor, 4 ... Shaft. Name of agent: Patent attorney Toshio Nakao and 1 other person +---i
Fig. 1 2' - Xie Kusu 3 - 11 permanent layer width ÷ 1'

Claims (6)

[Claims] (1) A resin magnet structure in which a composite of a magnet material and a binder is integrally molded into a supporting member. (2) The resin magnet structure according to claim 1, wherein the supporting member is a molded article of a thermopolymerizable resin molding material containing 65% by volume or more of an inorganic filler. (3) The resin magnet structure according to claim 1, wherein the magnet material is a liquid-quenched Fe-BR-based magnet material (where R is Nd or/and Pr). (4) The resin magnet structure according to claim 1, wherein the binder is a polymer having an active hydrogen capable of reacting with an isocyanate group in at least its molecular chain and an isocyanate regenerated product. (5) Composite of magnet material and binder at 5.0g/cm^
The resin magnet structure according to claim 1, which is compressed to a density of 3 or more. (6) The resin magnet structure according to claim 1, wherein the supporting member has an engaging portion with the composite portion on the outer periphery.