JPS6311050A - Permanent magnet type motor - Google Patents

Abstract

PURPOSE:To constitute a small, high-performance motor, by a method wherein plate-shaped Fe-B-R (R: Nd or Pr) grains to constitute a cylindrical magnetic pole section are aligned by magnetic means and solidified by a resin composition. CONSTITUTION:A rotor 1 holds a cylindrical magnetic pole section obtained in that plate-shaped Fe-B-R (R: Nd or Pr) grains are aligned by magnetic means and solidified by a resin composition. A stator section is povided with outer yokes 2a and 2b, two inner yokes 3 in contact with each other back to back, and exciting coils 4a and 4b enclosed between these yokes.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a so-called permanent magnet rotor type rotor, which is widely used as a control drive for computer peripherals, printers, etc., and where technological innovation is active centered on miniaturization and weight reduction. Or it relates to a permanent magnet field type pulse motor or a DC motor. More specifically, the present invention relates to a cylindrical magnet of a small permanent magnet motor having at least two or more multipole magnets.

BACKGROUND ART Rare earth cobalt sintered magnets used in permanent magnet motors are formed into a cylindrical shape, and it is extremely difficult to make the magnets magnetically anisotropic in the radial direction of the shape. The main reason for this is that a difference in expansion coefficient occurs due to anisotropy during the sintering process, and this difference in expansion coefficient is also influenced by the degree and shape of magnetic anisotropy, but in general, it is due to isotropy. There is no other choice but to make it cylindrical. Therefore, the magnetic performance that would normally be 20 to 30 MGOe at the maximum energy product is reduced to about 5 MGOe in the radial direction of the cylinder. In order to install it in a permanent magnet motor that requires even higher dimensional accuracy, grinding is required after sintering, resulting in poor yields and S
Adding to the fact that M and Co are the main components, there is a poor balance between economy and performance. Furthermore, since baked crystals are generally mechanically fragile, some of them may scatter or transfer to the gaps and sliding parts between the rotor and stator of permanent magnet motors, making it difficult to maintain the motor's function and ensure its reliability. There is a risk that there will be no serious impact.

On the other hand, in the case of rare earth cobalt resin magnets, the matrix resin can absorb the difference in expansion coefficient of the rare earth cobalt which is magnetically anisotropic in the radial direction, so a cylindrical magnet with magnetic anisotropy in the radial direction can be obtained. .

In recent years, if injection molded rare earth cobalt resin magnets are made magnetically anisotropic in the axial direction, the maximum energy product can be increased from 8 to 1.
It is known that 0 MGOe can be easily obtained. Furthermore, the density is approximately 30% lower than that of fired crystals, a high degree of dimensional accuracy can be ensured, and mechanical fragility is also improved.

For the above reasons, it is clear that rare earth cobalt resin magnets with magnetic anisotropy in the radial direction are more preferable as magnets for permanent magnet motors than rare earth cobalt sintered magnets.

The prior art related to the above-mentioned means for creating magnetic anisotropy in the radial direction of the rare earth cobalt resin magnet will be explained.

As means for generating a magnetic field in the radial direction of the resin magnet molding cavity, for example, as described in JP-A-57-170501, a mold in which a magnetizing coil is arranged around the outer periphery of the cavity, or It is necessary to use a mold in which the magnetizing coil is embedded. In this method, a high-voltage, large-current power source is used to generate a magnetic field of a predetermined strength within the cavity, and the magnetomotive force is increased.

Problems to be Solved by the Invention However, in order to effectively focus the magnetic flux excited by the magnetized coil from the outer periphery of the mold into the cavity by the yoke, the magnetic path length must be lengthened, especially in small permanent magnet motors. In the case of a cylindrical magnet, a considerable portion of the magnetomotive force is consumed as leakage magnetic flux, so it is sometimes difficult to provide sufficient magnetic anisotropy in the radial direction.

In other words, there is a contradiction between the above-mentioned high dimensional accuracy and the miniaturization and high performance of a permanent magnet motor, which can be obtained by making a rare earth cobalt resin magnet, which is not mechanically fragile, magnetically anisotropic in the radial direction. was there.

The object of the present invention is to make a permanent magnet motor equipped with the above-mentioned multi-pole magnetized cylindrical resin magnet capable of further miniaturization and higher performance.

Means for Solving the Problems The present invention is a permanent magnet motor in which plate-shaped Fe-B-R (R is Nd or/and Pr) particles constituting the magnetic pole part of a cylindrical magnet are magnetically aligned and processed using resin. It is immobilized with a composition.

Function First, the permanent magnet type motor referred to in the present invention has a structure determined based on the design concept of the motor, and is either a so-called permanent magnet rotor type or a permanent magnet field type. There is no problem. Specifically, pulse motors and various DC motors are exemplified. However, the magnets of these permanent magnet motors are multi-pole magnetized, that is, cylindrical magnets having at least a plurality of magnetic poles. However, the cylindrical shape in the present invention can include all shapes such as a ring shape, a cylindrical shape, and a cylindrical shape, and furthermore, the magnetic pole part and the non-magnetic pole part do not necessarily have a uniform shape or a homogeneous shape. There is no problem.

Next, the plate-like Fe-B-R (R is Nd or/and Pr) particles referred to in the present invention have the basic formula N d + -x (Fe
It has a composition represented by ly, By)x.

(However, 0.5≦X≦0.9, 0.05≦Y≦0.10)
Specifically, l'Jdo, 87 ()'eo, s3. B
O, 07) A molten alloy whose basic formula is exemplified by 0.87 is quenched into a ribbon piece through an orifice and a roll in an Ar atmosphere, and then pulverized as appropriate to obtain a thickness of approximately 10 μm.
It refers to plate-shaped particles with a length of several tens to hundreds of μm in the longitudinal direction. These plate-like particles are, for example, Orthohombic and T
Extremely fine Fe-
It is thought to have a microstructure in which B-R ternary magnet phases are scattered, and is magnetically isotropic. Incidentally, it is desirable that such plate-like particles have a film formed on the surface of the particles, such as a monomolecular film or more, such as carbon functional silane. Examples of carbon functional silane include γ-glycidoxyprobyltriethoxysilane,
γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane,
β+ 3.4 epoxy)ethyltrimethoxysilane, γ
-Metacaptopropyltrimethoxysilane is an example, but other organic compounds such as organic titanate compounds can also be used as appropriate.

As a means for magnetically aligning the plate-shaped Fe-BR particles, any known method for generating a magnetic field in a molding cavity can be appropriately used. For example, irrespective of the magnetic pole position of the magnet in a permanent magnet motor, the magnetic field generating means for uniformly aligning the plate-shaped Fe-B-R particles over the entire permanent magnet includes a magnetic yoke and a non-magnetic yoke surrounding the molded cavity. An example of a method is to use a mold in which a magnetizing coil is arranged on the outside, or a mold in which a magnetizing coil is embedded in the outer periphery of a cavity. This method uses a high voltage, large current type power source to generate a predetermined magnetic field strength within the cavity. On the other hand, when plate-shaped Fe-B-R particles are magnetically aligned only at the magnetic pole portions of the permanent magnets of a permanent magnet type motor, the molding cavity magnetic field generating means is such that magnetic pole portions corresponding to predetermined positions around the cavity are aligned. An example of this method is to use a mold in which an alignment yoke is installed and a conducting wire is provided inside the yoke. In this method, conductive wires installed within the orientation yoke are energized and excited. Therefore, an instantaneous DC power supply that inputs a commercial frequency AC power source and generates a pulse current using the All Cyrisk full-wave phase control method, or an instantaneous DC power source that boosts and rectifies it to a predetermined DC voltage, charges a group of capacitors, and then discharges it through Cyrisk. It uses a power source to generate a pulsed magnetic field. However, the present invention is not limited to the typical magnetic field generating means described above.

Next, the resin composition for fixing the plate-like Fe-BR particles in the present invention includes all polymer compounds ranging from thermoplastic resins to thermosetting resins. Furthermore, processing aids, plate-like Fe
-B-R Various known additives such as a plasticizer for promoting magnetic alignment of particles (reducing viscosity) and an antioxidant for imparting thermal stability can be appropriately added as necessary.

The selection of the resin composition, its formulation, or the plate-like Fe-
The magnetic field generating means for magnetically aligning the BR particles, etc. are appropriately determined individually within a range that ensures the characteristics and reliability of the permanent magnet motor according to the present invention.

Example Examples of the present invention will be described below along with comparative examples.

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

(Manufacture of permanent magnet material) Atomic composition N obtained by melting in a high frequency melting furnace in an Ar atmosphere
do, +3(1;' 6o, s3.80.07) 0
．． The alloy No. 87 is continuously dropped into the gap between the rolls through an orifice to form a quenched ribbon piece, and the quenched ribbon piece is crushed as appropriate to form a piece with a thickness of about 10 μm as shown in Figure 1.
1. Plate-shaped Fe-BR particles ranging in size from several tens to several hundred μm in the longitudinal direction were obtained.

The plate-shaped Fe-BR particles were treated with γ-aminopropyltrimethoxysilane according to a conventional method, and then treated with dicyandiamide/epoxide oligomer (equiv-ratio).
Mixed with epoxy resin consisting of. However, the epoxide oligomer was diglycidyl ether bisphenol A with a molecular weight of 380, and the blending ratio of the epoxy resin containing the epoxide oligomer as a main component to the plate-shaped Fe-BR particles was 3% by weight.

On the other hand, as a conventional example, 93.5% by weight of S m Co 5
Injection molding type rare earth cobalt/polyamide-12 pellets were produced by kneading and granulating the cobalt and polyamide-12 in a conventional manner.

Magnetically isotropic density 485g/c+ made by fixing the above 97% by weight plate-shaped Fe-BR particles with epoxy resin
The magnetic performance of the permanent magnet J is such that the maximum energy product in a measuring magnetic field of 25 KOe is 4 MGOe, and 93.5 wt% rare earth cobalt is placed in an axial magnetic field of 15 KOe.
Regarding the magnetic performance of the magnetically anisotropic permanent magnet fixed with polyamide-12, the maximum energy product in the same measured magnetic field was 9°7 MGOe.

(Manufacture of permanent magnet) A mold cavity is filled with 97% by weight of plate-shaped Fe-BR particles/epoxy resin. However, the mold cavity has a cylindrical shape that can be exemplified as the permanent magnet of the permanent magnet type motor that is the subject of the present invention, and its specific dimensions are an outer diameter of 13
mm, inner diameter 5.5+nm, and height 4.1+nm.

A particle alignment yoke having a predetermined magnetic pole portion is installed around the cavity, and a conducting wire is provided within the yoke. The conductive wire is connected to an instantaneous DC power supply that boosts and rectifies the DC voltage to a predetermined value, charges the capacitor group, and then discharges it via a thyristor.

97% by weight plate-like Fe-B filled in the mold cavity
The opposing punches were moved until the apparent density of -R particles/epoxy resin was near, and then a current with a peak value of 20 KA and a pulse width of 400 μsec was applied to the conductive wire to generate a magnetic field in the cavity. As a result, the plate-shaped Fe-B-2 particles within the cavity are aligned with the magnetic pole portion as the center.

Then, 97% by weight plate-like Fe-B-R was
The particles/epoxy resin are compressed to a density of 5.0 g/cwt, and then the epoxy resin is cured to a density of 9.
7% by weight plate-shaped Fe-B-2 particles were immobilized. (Example of the present invention) No. 21N(a) and (b) are made of the resin composition while the plate-shaped Fe-B-2 particles constituting at least the magnetic pole part of the cylindrical magnet according to the example of the present invention are aligned by magnetic means. This is a scanning electron wlR photograph showing the immobilized appearance. however,
(a) shows a magnetic pole part in which plate-shaped Fe-B-2 particles are fixed in an aligned manner, and (b) shows a magnetic pole part in which plate-shaped Fe-E3-2 particles are fixed in a random manner. From the figure, it is clear that in the magnetic pole part where the plate-shaped Fe-B-2 particles are aligned by magnetic means, the plate-shaped Fe-B-2 particles are present at a higher concentration than between one of the magnetic poles.

On the other hand, 97% by weight plate-shaped Fe-BR particles/epoxy resin were compressed as they were to a density of 5.0/cra, and the epoxy resin was further cured to produce a permanent magnet having the same size and shape. (Comparative Example) Furthermore, a mold was prepared in which a magnetic yoke and a non-magnetic yoke were alternately combined to surround a mold cavity having the same size and shape as the permanent magnet, and a magnetizing coil was arranged on the outside. While continuously generating a magnetomotive force of 60°000 AT with the magnetizing coil, 93.5 M mass % rare earth cobalt/polyamide-12 was melt-injected, and the polyamide-12 was cooled and solidified in the cavity to create a radial direction. Magnetically anisotropic rare earth cobalt was immobilized on the surface.

The density of this permanent magnet was 5.5 g/c-. (Conventional Example) (Characteristics of Permanent Magnet Type Motor) FIG. 3 shows the configuration of an exemplary symmetrical permanent magnet rotor type motor. 1 in the figure indicates the outer peripheral surface with an outer diameter of 81.
Examples of the present invention with polar uniform magnetization (that is, permanent magnets in which plate-shaped Fe-B-2 particles constituting at least the magnetic pole portion of a cylindrical magnet are fixed with a resin composition while being aligned by magnetic means), comparative examples, and conventional examples. This is a rotor equipped with an example. The stator section includes outer yokes 2a and 2b, two inner yokes 3 joined back to back, and excitation coils 4a and 4b housed between them. Such a so-called PM type pulse motor performs an operation in which the rotor is displaced by one step angle due to the magnetomotive force of the excitation coil corresponding to one pulse current.

FIG. 4 is a characteristic diagram showing the relationship between the pulse rate and pullout torque of the permanent magnet rotor type motor. In the figure, 1 is an example of the present invention, 2 is a comparative example, and 3 is a conventional example.

As is clear from the figure, in the example of the present invention, that is, in the permanent magnet motor in which plate-shaped Fe-B-2 particles constituting at least the magnetic pole portion of a cylindrical magnet are fixed with a resin composition while being aligned by magnetic means, Distributed plate-like Fe-B
- A permanent magnet motor equipped with a comparative example in which two particles are immobilized with a resin composition, or a conventional example in which rare earth cobalt particles with magnetic anisotropy in the radial direction are immobilized in a resin composition. It exhibits superior performance compared to .

Effects of the Invention As described above, the present invention is extremely advantageous in miniaturizing and increasing the performance of a permanent magnet rotor type motor or a permanent magnet field type motor using a permanent magnet magnetized with two or more multipoles.

[Brief Description of the Drawings] Fig. 1 is a micrograph showing the particle structure of plate-like Fe-B-R particles according to the present invention, and Fig. 2 (a) is a photomicrograph showing the particle structure of plate-like Fe-B-R particles according to the present invention.
A micrograph showing the arrangement and immobilization of R particles, (b) a microphotograph showing the random immobilization, Fig. 3 is an exploded perspective view showing the structure of a permanent magnet motor, and Fig. 4 shows the pulse rate. FIG. 3 is a characteristic diagram showing the relationship between pullout torque and pullout torque. Name of agent: Patent attorney Toshio Nakao and one other person

Claims (1)

[Claims] Plate Fe-B-R constituting at least the permanent magnet magnetic pole part
(R is Nd or/and Pr) A permanent magnet type motor in which particles are fixed with a resin composition while being aligned by magnetic means.