JP2003189560A - Manufacturing method of core-integrated magnet rotor and permanent magnet motor - Google Patents

Abstract

(57) [Problem] A conventional core-integrated magnet requires a reduction in magnet [BH] max and an increase in magnet wall thickness due to an increase in epoxy resin, and the original performance of magnet powder cannot be reflected in motor characteristics. SOLUTION: A magnet powder compact, an iron powder compact and a rotating shaft are heated to simultaneously harden the three members integrally, thereby producing an iron core integrated magnet rotor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention assembles an annular or arc-shaped magnet powder compact, an iron powder compact, and a rotary shaft into a predetermined structure, and then heats them so that they are integrated simultaneously. The present invention relates to a method for manufacturing a magnet rotor that is rigidized into a rigid body. The present invention relates to a method for manufacturing a magnet and a magnet rotor including a rotary shaft all at once in the process of manufacturing the magnet, in order to cure the epoxy resin contained in the magnet and the iron powder compact. magnet,
Since the iron core and the rotating shaft are integrally rigidified by a low thermo-mechanical load, they have a high density and a maximum energy product (BH) ma.
It is possible to provide a permanent magnet type motor equipped with a thin magnet having a large x. Therefore, the present permanent magnet type motor has high output and high efficiency of a surface magnet type synchronous motor used as a drive source of OA, AV, home electric appliances, and air conditioners having outputs of several to several tens of W, and a permanent magnet type step motor. Can be contributed to.

[0002]

2. Description of the Related Art Motors mounted in office automation equipment, audio-visual equipment, home appliances, air conditioners, etc. have been made efforts to reduce the size and weight of the equipment and save energy. However, power consumption of homes, factories, and offices (about 900 billion kWh / 96
In each case, the power consumption by the motor is high, and it is estimated that the total power consumption will exceed 50%. In recent years, in order to protect the global environment such as prevention of global warming and protection of the ozone layer, further development and spread of high efficiency motors are required. To improve motor efficiency, it is necessary to reduce loss or increase output. One of the keys to higher output is the magnet, and it is important to reflect the performance of the magnet material in the motor performance. By the way, the conditions required for the magnets to be applied to individual motors are as follows: magnetic characteristics that can give a static magnetic field required for the air gap, stability represented by irreversible demagnetization, and an arbitrary shape depending on the desired shape. It is necessary to obtain the highest degree of consistency in the four points of overall economic efficiency from securing the resources of raw materials to implementation. Generally, motor efficiency and miniaturization are in a contradictory relationship, and in a comparatively small magnet motor of several hundred W or less, it is necessary to advance fusion of magnets and motor manufacturing.

The object of the present invention is, for example, for a magnet rotor having a structure in which a magnet is arranged on the surface of a rotor generally used for PM type step motors and synchronous motors, and is aimed at fusing magnets and motor manufacturing. is there. For example, R ₂ TM ₁₄ B containing capsules containing liquid epoxy oligomer
An iron core-integrated magnet that compresses a magnet powder compound having a phase on the outer peripheral side surface of the iron core and heat-cures the produced iron core-integrated magnet powder compact is described in M. Wada, F.F. Yamashit
a, "Nd-Fe-B Resin Bonded M
Agnet to the Brush-less M
Otor for Home Appliance Us
e ", Proc. 10th Int. Workshop
on Rare-Earth Magnets an
d Their Applications (II), p
p. 91-101 (1989). Figure 1
[FIG. 3] is a process diagram of producing the powder compact of the iron core integrated magnet described in the above paper by powder molding. However, in the figure, A is a filling process, B is a compression process, C is a mold release process, D is a heat treatment process, 11 is a laminated core, 12 is a compound, 13
Is a die, 14 is a lower core, 15 is a lower punch, 16 is a feeder cup, 17 is an upper punch, 18 is an upper core, 19 is a magnet compact, and 20 is an epoxy resin contained in the magnet compact, which is heat-cured. Later it was a magnet with an integrated iron core. This magnet becomes a magnet rotor by press-fitting the rotating shaft into the iron core, but since the magnet is normally compressed at 8-10 ton / cm ² according to the process in the figure, it is usually 0.65 to 0.70% when released from the mold. There is a spring back. However, in this technique, the spring back of the magnet is suppressed so that the iron core and the magnet are not bonded to each other, and the iron core integrated magnet that secures the mechanical strength and dimensional accuracy of the magnet rotor is used.

FIG. 2 shows that the content of the magnet powder having the R ₂ TM ₁₄ B phase is 95 wt. % Compound to a thickness of 1 m on the outer surface of the iron core with an outer diameter of 48 mm and a product thickness of 11 mm
The sectional view of the boundary part of the magnet and the iron core of the iron core integrated magnet of m is shown. It is understood that the magnet A and the iron core B are integrally rigidified without an adhesive layer or voids.

FIG. 3 shows an iron core integrated magnet in which an annular magnet having a thickness of 1 mm is arranged on the outer circumference of the iron core having an outer diameter of 48 mm and a product thickness of 11 mm, and a springback with respect to the content of the magnet powder having R ₂ TM ₁₄ B phase, FIG. 3 is a characteristic diagram showing the relationship between the joining strength (shearing force) between the magnet and the iron core of the iron core integrated magnet. As shown in the figure, 95 wt. % Or less (5 wt.% Or more of epoxy resin), springback is suppressed to 0.07% or less, which is 1/10 or less of normal, and it is understood that the bonding strength between the magnet and the iron core is obtained. It

[0006]

However, in order to suppress the springback of the magnet as described above to 0.07% or less and to manufacture an iron core integrated magnet having high shear strength, the epoxy resin contained in the magnet is used. The ratio must be 5% or more.

FIG. 4 is a characteristic diagram showing the relationship between the density and magnetic characteristics of the magnet. As shown in the figure, the magnetic performance of the magnet (the residual magnetization Ir and the maximum energy product [BH] max) depends on the density of the magnet. For example, if the content of the epoxy resin is 1.5 wt. % Alloy composition Nd ₁₂ Fe ₇₇ Co ₅ B ₆ compounded with magnet powder having R ₂ TM ₁₄ B phase 9
The magnet produced by compressing at 80 MPa and heating and curing the epoxy resin of the magnet powder compact has a density of 6.1 Mg / m ³ , 4
[BH] max after magnetizing with a pulsed magnetic field of MA / m is 83 kJ / m ³ . On the other hand, the ratio of the epoxy resin that is the minimum required for manufacturing the iron core integrated magnet is 5 wt. %
The magnet produced by compressing a magnet powder compound of the same alloy composition Nd ₁₂ Fe ₇₇ Co ₅ B ₆ at 980 MPa and heating and curing the epoxy resin of the magnet compact is 5.4-.
A density of 5.5 Mg / m ³ or more cannot be obtained. Therefore, [BH] m after magnetizing with a pulsed magnetic field of 4 MA / m
ax is 58 kJ / m ³ , which is the same as that of a magnet having a density of 6.1 Mg / m ³ despite using the same magnet powder [BH].
max is reduced by approximately 30%. Therefore, when the iron core integrated magnet is manufactured by the method according to the above technique, the magnet [BH]
There is a problem that the reduction of max is unavoidable, and in this sense, the original performance of the magnet powder cannot be sufficiently reflected in the motor performance.

FIG. 5 shows the appearance of a typical magnet rotor used in a permanent magnet type motor or the like. However, in the figure, 1 is, for example, 9 magnet powder compound having R ₂ TM ₁₄ B phase.
An annular magnet, 2 is a rotating shaft, and 3 is a molding material, which is manufactured by compressing at 80 MPa and heating and curing the epoxy resin of the magnet powder compact. This magnet rotor is manufactured by loading the rotary shaft 2 together with the ring-shaped magnet 1 into the mold cavity and inserting PBT (polybutylene terephthalate) or PET into the gap between them.
For example, a glass fiber reinforced molding material in which a polymer material such as (polyethylene terephthalate) is used as a matrix is
A magnet rotor is produced by injection filling under high temperature and high pressure of 0 to 280 ° C. and 1000 to 1200 kgf / cm ² , and by cooling and solidifying in a mold to fix the magnet and the rotating shaft by the molding material. Was there. In this case, the magnet density is 6.1 Mg / m ³ , and [BH] max after magnetizing with a pulsed magnetic field of 4 MA / m is 83 kJ / m ³ and a high-performance magnet or a thin-walled magnet is placed in the mold. When loaded, the magnet cannot withstand thermomechanical loads. Therefore, in order to secure the yield of the magnet rotor, it is unavoidable to increase the amount of epoxy resin contained in the magnet or to increase the thickness of the magnet. There was a problem that the performance could not be sufficiently reflected in the motor performance.

An object of the present invention is to reduce the thermomechanical load on the magnet by integrating the magnet rotor manufacturing process with the magnet manufacturing process, and to simultaneously realize a high density and high magnetic performance thin-walled magnet and a rotary shaft. A manufacturing method of integrally rigidifying with an iron core. Another object of the present invention is to provide a permanent magnet type motor capable of sufficiently reflecting the original performance of magnet powder in the motor performance.

[0010]

That is, according to the present invention, a ring-shaped or arc-shaped magnet powder compact, a rotary shaft, and an iron powder powder compact are assembled and fixed in a predetermined shape as a magnet rotor, and then 3 People are heated at the same time. And, it is a method of manufacturing an iron core integrated magnet rotor in which at least the magnet, the powder iron core, and the rotary shaft are rigidified simultaneously by thermosetting an epoxy resin contained in at least the iron powder green compact. In particular, when heating the three simultaneously, at least 30 g / cm ^{2 of} iron powder compact
Applying the above loads is effective in stabilizing the dimensional accuracy and the joint strength of the iron core.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention assembles and fixes a ring-shaped or arc-shaped magnet powder compact, a rotary shaft, and an iron powder powder compact into a predetermined shape as a magnet rotor, and then simultaneously heats the three members. To do. And, it is a method of manufacturing an iron core integrated magnet rotor in which at least the magnet, the powder iron core, and the rotary shaft are rigidified simultaneously by thermosetting an epoxy resin contained in at least the iron powder green compact. In particular, when simultaneously heating three members, applying a load of at least 30 g / cm ² to the iron powder green compact is effective in stabilizing the dimensional accuracy and bonding strength of the iron core.

The iron powder compact used in the present invention means Fe, Fe-Ni, Fe-Co, Fe having a saturation magnetization of 1.3 T or more.
A powder of a granular iron powder compound composed of one or more selected from the group of -Si, Fe-N, Fe-B, an epoxy resin, and an additive to be added if necessary. is there. The epoxy resin of iron powder compound is composed of epoxy oligomer which is solid at room temperature and powdery latent curing agent, and its content is at least 3w.
t. It is desirable to set it to be at least%.

The iron powder compound is prepared by first wet mixing iron powder with an organic solvent solution of an epoxy oligomer which is solid at room temperature. Next, the solid block obtained by heating and removing the organic solvent in the wet mixture is crushed and classified into granules at room temperature. Finally, it is prepared by dry-mixing a powdery latent curing agent and optionally added additives.
The epoxy resin that constitutes the iron powder green compact formed by powder-molding such an iron powder compound is an epoxy oligomer that is solid at room temperature and a latent latent curing agent in powder form. There is no problem even if spherical microcapsules are used together. However, when microcapsules are used in combination, it is important to first dry-mix the iron powder and the microcapsules in order to ensure uniform dispersion. Next, at room temperature, an organic solvent solution of an epoxy oligomer that is solid at room temperature is wet mixed with a mixture of iron powder and microcapsules, and the organic solvent in the wet mixture is removed by heating, and then crushed and classified into granules. A dry mixture of a powdery latent curing agent and an additive which is appropriately added as required.

The epoxy oligomer referred to in the present invention is a compound having at least two oxirane rings in one molecule, and it must be solid at room temperature and easily soluble in an organic solvent such as acetone. As the epoxy oligomer, a novolak type epoxy oligomer having a softening temperature of 70 ° C. or more and an epoxy equivalent of 235 or less, which has an oxirane ring in the molecular chain and can be represented by the following chemical structure, can be preferably used.

[0015]

[Chemical 1]

The powdery latent curing agent referred to in the present invention includes one or more selected from the group of dicyandiamide and its derivative, carboxylic acid dihydrazide, diaminomaleonitrile and its derivative hydrazide. be able to. These are generally high-melting-point compounds that are poorly soluble in organic solvents, but those having a particle size adjusted to several to several tens of μm are preferable. Examples of the dicyandiamide derivative include o-tolylbiguanide and α-2 · 5-
Dimethyl biguanide, α-ω-diphenyl biguanide,
Examples include 5-hydroxybutyl-1-biguanide, phenyl biguanide, α-, ω-dimethyl biguanide, and the like. Further, as the carboxylic acid dihydrazide, succinic acid hydrazide, adipic acid hydrazide, isophthalic acid hydrazide,
p-Axybenzoic acid hydrazide and the like.

Next, the role of the powdery latent curing agent will be described with reference to the schematic view of FIG. In the figure, 51 is an iron powder compact, 54 is an iron powder, 55 is an epoxy oligomer of the iron powder compact 51, and 56 is a latent latent curing agent dispersed in the iron powder compact 51. Further, 52 is a magnet powder compact,
Reference numeral 57 denotes a magnet powder, 58 an epoxy oligomer constituting the magnet powder green compact 52, and 59 a powdery latent curing agent dispersed in the magnet powder green compact 52. The powdery latent curing agents 56 and 59 are dry-mixed at the end of the compound preparation process, and are uniformly dispersed on the surface and inside of the iron powder compact 51 and the magnet powder compact 52 as shown in the figure. And then exist. When these are heated, the contact surface 53 is formed between the iron powder green compact 51 and the magnet powder green compact 52 due to thermal expansion of the iron powder green compact 51 exceeding the amount of the epoxy resin.
Then, the powdery latent curing agents 56, 59 which are dispersed and present in the iron powder green compact 51 and the magnet powder green compact 52 are dissolved in the epoxy oligomers 55, 59 as shown by 60, 61,
It cures from that part. Such a curing reaction is applied to the contact surface 5
3 is also caused by the powdery latent curing agents 56 and 59 existing in 3 and reacts with the epoxy oligomers 55 and 59 to each other, whereby the iron powder green compact 51 and the magnet powder green compact 52 are produced.
And become chemically bound.

The upper limit of the particle size of the iron powder compound is 500 μm, and a lubricant is an essential component as an additive added to the iron-based powder compound. As the lubricant, a higher fatty acid having a melting point higher than at least the heat curing temperature of the epoxy resin or It is desirable to use higher fatty acid metal soap. If the upper limit of the particle size is 500 μm or less, the yield of the compound will decrease, and if it is 500 μm or more, the crosslinking density of the epoxy oligomer inside the granules forming the compound will decrease, resulting in heterogeneous curing, which is not preferable. In addition, FIG.
While the joining mechanism of the iron powder compact and the magnet powder compact as described in 1. is in progress, if the melt of the higher fatty acid or the higher fatty acid metal soap elutes on the contact surface 53 of FIG. Cause a decrease in height. Therefore, it is desirable that the lubricant being heat-cured is infusible and insoluble.

It is necessary that the above-mentioned iron powder compound is compression molded at room temperature under a molding pressure of at least 200 MPa to obtain an iron-based powder green compact having a porosity of 5% or less. As a result, the outer diameter of the iron powder green compact expands 0.7% or more due to the heat curing of the epoxy resin, and a magnet or rotating shaft and an adhesive layer are not formed near the surface of the iron powder compact, which is substantially sufficient. It becomes possible to secure the resin amount near the surface layer so that the bonding strength is exhibited.

The density of the powder iron core obtained by heating and hardening the iron powder green compact is 5.0-5.1M of the density of the ferrite sintered magnet.
It is preferably g / m ³ . As a result, when the density is increased, the inertia of the magnet rotor is increased, so that the control responsiveness in the high speed rotation region of the permanent magnet type motor is deteriorated. Also, the decrease in density decreases the magnetic permeability of the iron core,
This is because the static magnetic field in the air gap between the stator and the rotor, which is a permanent magnet type motor, decreases, causing a reduction in output and efficiency. Therefore, it is desirable that the direct current magnetic permeability of the dust core produced by heating and hardening the iron powder compact is 10 or more. This value is a level at which the effect of 50% or more of pure iron can be expected. In order to secure the joining strength and dimensional accuracy of the magnet rotor, it is preferable that the difference between the outer diameter of the iron powder compact and the inner diameter of the magnet compact is 100 μm or less. This level is a numerical value necessary to keep the outer peripheral runout of the magnet rotor about 50 μm or less with respect to the rotation axis. The obtained magnet rotor is directly combined with the stator without any post-processing to obtain a desired permanent magnet type motor. It is possible to do.

Next, as a method for producing the magnet powder compact, the magnet powder is wet mixed with an organic solvent solution of an epoxy oligomer which is solid at room temperature, and the organic solvent in the mixture is removed by heating.
The obtained solid block is crushed and classified at room temperature to form a granule, and finally, a magnetic powder compound is powder-molded by dry-mixing a latent latent curing agent in powder form and an additive optionally added as necessary. When the upper limit of the particle size of the magnet powder compound is 250 μm, it is possible to manufacture the magnet powder compact by powder molding with a thin shape of, for example, 1 mm or less with high dimensional accuracy. A lubricant is an essential component as an additive added to such a magnet powder compound, and as the lubricant, at least a higher fatty acid having a melting point higher than the heat curing temperature of the epoxy resin or a higher fatty acid metal soap is adopted. As described above, it is necessary to secure the bonding strength with the iron powder compact. Furthermore,
Make the epoxy resin constituents of the magnet powder compact and iron powder powder compact the same, and make the epoxy resin content of the iron powder powder compact 2.5 times or more than the epoxy resin content of the magnet powder compact. This is also effective from the viewpoint of securing the bonding strength with the iron powder compact.

Next, a preferable magnet will be described. The preferred magnet green compact in the present invention is an R-TM-B type alloy (provided that R is 10 to 20 at.%, At least one of rare earth elements including Y, TM is Fe or a part of Fe is Co. , B is 5 to 20 at.%), And is a green compact mainly composed of a magnetic powder obtained by molding a compound of a magnetic powder and an epoxy resin into a predetermined shape. The magnet powder has at least the R ₂ TM ₁₄ B phase and the magnet density is 5.
9-6.1 Mg / m ³ , 4 MA / m coercive force after pulse magnetization Hci 636-800 kA / m, and maximum energy product (BH) max 76-82 kJ / m ³ can be exemplified as preferable magnet characteristics. It is desirable that such a magnet is, for example, an iron core-integrated magnet rotor magnetized with a pole distance of 2.3 mm or more, and a permanent magnet type motor. On the other hand, in the case of the nanocomposite magnet powder having the αFe phase and the R ₂ TM ₁₄ B phase, the magnet density is 5.9-
6.1Mg / m ³ , 4MA / m Coercive force H after pulse magnetization
ci550-600 kA / m, maximum energy product (B
H) max 76-82 kJ / m ³ can be illustrated as an example of a preferable magnet characteristic. Such a magnet
As an iron core integrated magnet rotor with a pole distance of 2 mm or less,
When mounted on a permanent magnet type motor, it is effective for increasing the output of the motor.

[0023]

EXAMPLES Next, the present invention will be described in more detail by way of examples. However, the embodiment of the present invention is not limited to the embodiment.

[Production of Magnet Powder Compound] Magnet Powder Compound A First, magnet powder having an alloy composition of Nd ₁₂ Fe ₇₇ Co ₅ B ₆ and R ₂ TM ₁₄ B phase is made into granules with a solid epoxy oligomer at room temperature. Here, epoxy oligomer (polyglycidyl ether-o-cresol-formaldehyde novolac, softening temperature 80 ° C., epoxy equivalent 215
˜235, specific gravity 1.21) is completely dissolved in an organic solvent (acetone), and 50 wt. % Solution was wet mixed with a predetermined amount of magnet powder. The wet mixture was heated to 80 ° C. to remove the solvent, and the obtained solid block was crushed to give a particle size of 53-2.
The granules were 50 μm. The granules at this stage are only magnets and epoxy oligomers. Therefore, the curing reaction of the epoxy oligomer cannot occur during heating for removing the solvent, for example.

Next, the above-mentioned granules having a particle size of 53 to 250 μm,
The powdery latent curing agent and the lubricant were dry mixed. However, as the powdery latent curing agent, an acid having the following chemical structure with an average particle diameter of 30 to 50 μm obtained by reacting hydrazine with an addition reaction product of 1,2-dodecanoic acid ester 1 mol and acrylic acid ester 2 mol Hydrazide was used.

(NH ₂ NHCOCH ₂ CH ₂ ) ₂ N (C
H ₂ ) ₁₁ CONHNH ₂ The melting point of this compound is 120 to 130 ° C. In the case of blending with the epoxy oligomer, a higher crosslinking density tends to be obtained when the amount of the powdery latent curing agent is slightly increased rather than the amino active hydrogen equivalent to the total epoxy equivalent or the chemical equivalent ratio. The actual mixing ratio with respect to the epoxy oligomer here is about 0.102 to 0.613 wt.
%. The lubricant is calcium stearate powder having an average particle size of 5 μm, and is 0.2 per 100 parts by weight of the granules.
It was made into a weight part.

The yield of the above magnet powder compound is 1
It was 98% in 0 kg batch processing.

Magnet powder compound A Same alloy composition as in the previous section Nd ₁₂ Fe ₇₇ Co ₅ B ₆ , R ₂ TM ₁₄
The magnetic powder having phase B and the microcapsules represented by the following structure were placed in a kneader, and the blade was rotated to dry-mix. Then, in advance, an epoxy oligomer (diglycidyl ether bisphenol A, softening temperature 95 ° C., epoxy equivalent 1040, specific gravity 1.20) was added as an organic solvent (acetone).
Completely dissolved in 50 wt. % Solution was wet mixed with a predetermined amount of magnet powder. The wet mixture was heated to 80 ° C. to remove the solvent, and the obtained solid block was crushed to give a particle size of 53.
Granules of ˜250 μm. The granules at this stage are only magnets and epoxy oligomers. Therefore, the curing reaction of the epoxy oligomer cannot occur during heating for removing the solvent, for example.

[0029]

[Chemical 2]

Next, the above-mentioned granules having a particle size of 53 to 250 μm,
The powdery latent curing agent and the lubricant were dry mixed. However, as the powdery latent curing agent, an acid having the following chemical structure with an average particle diameter of 30 to 50 μm obtained by reacting hydrazine with an addition reaction product of 1,2-dodecanoic acid ester 1 mol and acrylic acid ester 2 mol Hydrazide was used.

(NH ₂ NHCOCH ₂ CH ₂ ) ₂ N (C
H ₂ ) ₁₁ CONHNH ₂ The melting point of this compound is 120 to 130 ° C. In the case of blending with the epoxy oligomer, a higher crosslinking density tends to be obtained when the amount of the powdery latent curing agent is slightly increased rather than the amino active hydrogen equivalent to the total epoxy equivalent or the chemical equivalent ratio. The actual mixing ratio with respect to the epoxy oligomer here is about 0.102 to 0.613 wt.
%. The lubricant is calcium stearate powder having an average particle size of 5 μm, and is 0.2 per 100 parts by weight of the granules.
It was made into a weight part. The yield of this magnet powder compound is 1
It was 99% in 0 kg batch processing.

The powder moldability and the particle size distribution of the granules of the above-mentioned two types of magnet powder compounds are shown in (Table 1) and (Table 2). From the table, all of the magnet powder compounds according to the present invention have powder moldability based on numerical values such as powder fluidity.

[0033]

[Table 1]

Next, the magnet powder compound was made into a green compact by changing the compression pressure, and the epoxy resin of the green compact was heated and hardened. Show. The present magnet manufactured at a compression pressure of 980 MPa can easily obtain a density of 6.00 Mg / m ³ , and as a result, a maximum energy product of 80 kJ / m ³ .

[0035]

[Table 2]

[Production of Iron Powder Compound] The iron powder compound was prepared by substituting atomized iron powder for the magnet powder described in the preceding paragraph, and the epoxy resin content was 6.5 wt. %. This compound was subjected to 10 kg batch treatment twice, and the yield was within 99 ± 1%.

Table 3 shows the powder moldability, expansion coefficient upon curing, radial crushing strength, and density of the iron powder compound. As shown in the table, the iron powder green compact obtained by compressing the iron powder compound at 400 MPa was about 0.
75% diameter expansion.

[0038]

[Table 3]

[Production of green compact] The dimensions of the main parts of the magnet powder compact and the iron powder compact mold used in this example are shown in FIGS. 7 (a) and 7 (b). The magnet powder compact is 6.8.
A magnetic powder compound of -6.9 g was filled in the cavity configured in Fig. 7 (a), and compressed at 980 MPa to produce. The iron powder green compact was prepared by filling 26.7-26.8 g of the iron powder compound into a cavity constituted by FIG. 7B and a shaft having a diameter of 2.995 mm and compressing it at 400 MPa.

[Fabrication of Iron-Integrated Magnet Rotor] In this embodiment, 6.8-6.9 g of magnet powder compacts 71a and 26.
8-26.9 g of iron powder green compact 72a is individually prepared,
These were combined with a rotating shaft 73 having a diameter of 2.995 mm as shown in FIG. 8, and a magnet rotor was produced by heating and curing an epoxy resin. In this experiment, the manufactured iron powder compact was assembled and fixed in a magnet rotor shape together with a rotary shaft so as to be sandwiched between both end surfaces by a jig treated with Teflon (registered trademark), and then heat-cured.

FIG. 9 shows one iron powder compact and one magnet powder compact.
FIG. 3 is a characteristic diagram in which the combination of individual pieces and a rotating shaft, the joint strength when only the iron powder compact is heated, and the outer diameter expansion coefficient of the iron powder compact alone are plotted against temperature. It is understood that expansion of the iron powder green compact is observed from around 120 ° C. when the epoxy resin is hardened, and the size thereof depends on the temperature. The joint strength (shear fracture load) of the magnet and the iron core is 140
Although it greatly increased from around ℃, the joint strength between the shaft and the iron core gradually increased. It is assumed that the cause of the increase in the bonding strength between the magnet and the iron core at around 140 ° C. is an increase in the internal heat storage due to the heat generated by the hardening of the epoxy resin contained in the iron powder compact. A heating temperature of 120 to 140 ° C. is necessary for the homogeneous curing reaction in this case.

FIG. 10 is a characteristic diagram showing heating temperature dependence of expansion coefficient of axial dimension and magnet diameter. As is clear from the figure, when a load (120 g) is applied to the iron powder green compact during heating, a remarkable increase in the expansion coefficient of the iron powder green compact is suppressed at 140 ° C. or higher. Further, at 130 ° C., the expansion coefficient of the iron core becomes almost constant regardless of the load. On the other hand, the expansion coefficient of the magnet diameter (outer diameter of the magnet) has a minimum value in the vicinity of 125 to 130 ° C. When a weight is added to the iron powder compact (compacted iron core) at the time of heating, the expansion coefficient is the same at the same temperature. It became clear that it would decrease. On the other hand, expansion of the iron powder compact (compacted iron core) due to overheating may cause cracking of the magnet. In order to suppress the cracking of the magnet, it was effective to suppress the expansion due to the internal heat accumulation of the curing heat of the epoxy resin contained in the iron powder compact (compacted iron core).

Next, the optimum curing temperature 13 in this embodiment is set.
A study was conducted to optimize the load at 0 ° C. FIG. 11 shows
FIG. 9 is a characteristic diagram showing a dimensional change with respect to a load applied to two iron powder compacts of the iron core integrated magnet rotor as shown in FIG. 8. As shown in the figure, the dimensional change rate of the diameter (magnet outer diameter) of the iron core-integrated magnet rotor due to heat curing is hardly affected by the load.
However, the axial dimensional change rate of the iron core integrated magnet rotor (powdered iron core) starts to decrease when the load exceeds 120 g. Then, when the load becomes 320 g (30 g / cm ² or more),
The rate of dimensional change in the axial direction of the iron core integrated magnet rotor (powdered iron core) due to hardening becomes almost zero. Therefore, the dimensional accuracy in the axial direction of the iron core integrated magnet rotor is determined by the optimum curing temperature (130
There is an optimum load value to be applied to the iron powder green compact during heat curing.

As described above, in the present embodiment, it was found that the use of the optimum curing temperature (130 ° C.) and the optimum load (30 g / cm ² or more) is effective for ensuring the dimensional accuracy of the iron core integrated magnet rotor. Therefore, the curing time (heating time) was further examined. FIG. 12 is a characteristic diagram showing the diameter of the magnet rotor integrated with the iron core (magnet outer diameter) and the axial dimensional change rate with respect to the curing time. The change rate of the diameter of the magnet rotor integrated with the iron core (outer diameter of the magnet) is almost constant with respect to the heating time. Further, the axial dimensional change rate has a larger variation than the magnet rotor diameter (magnet outer diameter) change rate, but the absolute value is as small as 1/2 or less.

From the above, the outer diameter of the iron core integrated magnet rotor is 30.100 ± 0.01 mm, and the axial dimension is 18.80.
It was ± 0.06 mm (n = 50). It can be said that this dimensional accuracy is at a high level so that it can be directly incorporated into the stator as it is to form a permanent magnet type motor without post-processing.

FIGS. 13 (a) and 13 (b) are sectional views of the joint portion between the magnet and the iron core of the iron core integrated magnet rotor. In the figure, 81 is an iron core, 82 is a magnet, and FIG. 13 (b) is an enlarged view of portion C in FIG. 13 (a). Thickness 38-
The thickness of the epoxy resin layer existing at the boundary of the magnet powder of 40 μm is estimated to be 0.3 μm, but it is understood that the boundary portion between the iron core and the magnet is also bonded with a gap almost equal to that.

FIG. 14 is a characteristic diagram showing the joining strength of the iron core and the magnet with respect to the amount of epoxy resin of the iron powder compact. In the figure, 91 is the expansion coefficient of the iron powder green compact due to heat hardening, 9
2 indicates the expansion coefficient of the magnet powder compact by heat curing, and 93 indicates the bonding strength between them. However, the compression pressure of the iron powder compact is 400 MPa, and that of the magnet powder compact is 980 MPa. As shown in the figure, the bonding strength is developed in the vicinity of the point P where the expansion coefficients of both green compacts substantially overlap with each other, and when the expansion coefficient of the iron powder green compact increases, the bonding strength also increases accordingly. That is, the magnet has a compression pressure of 980 MPa and a magnet pressure of 5.9-6.0 M.
In order to obtain a density of g / m ³ , 3 wt. %, But the epoxy resin required for the iron powder green compact to be rigidified integrally with the magnet is 3 wt. It can be said to be over%.

FIG. 15 shows 7.5 wt. FIG. 3 is a characteristic diagram showing the distribution of epoxy resin from the outer peripheral surface of the iron core obtained by heating and hardening the iron powder green compact of 10% to the inner diameter direction. As shown in the figure, when the iron powder green compact is heated and hardened, the epoxy resin on the surface of the iron core has a remarkably high concentration compared with the inside.

FIG. 16 shows 7.5 wt. %
FIG. 3 is a characteristic diagram showing the amount of epoxy resin on the outer peripheral surface of the iron core obtained by heating and curing the iron powder green compact of FIG. In the figure, 95 is the surface of the powder compact of iron powder, and 96 is the heat-hardened iron core. As is clear from the figure, it is understood that the compression pressure applied to the iron powder compound is 300 MPa or more, preferably 400 MPa or more. The porosity present in the iron powder compact compacted at 400 MPa or more is reduced to 5% or less.
Since the decrease in the porosity causes the epoxy resin on the surface of the iron core to have a high concentration due to the heat curing, it is desirable that the compression pressure of the iron powder compound is 400 MPa or more, or the porosity of the iron powder green compact is 5% or less. .

[Joint Strength of Dust Iron Core and Shaft] The iron core and the rotating shaft (diameter 2.995) of the iron core integrated magnet rotor shown in the preceding paragraph.
mm) was examined. However, the measurement is at room temperature (2
The maximum stress (kgf) when the end face of the iron core was fixed at 4 ° C and a load was applied to the opposite shaft end at a crosshead speed of 5 mm / min was determined as the shear strength. FIG. 17 is a characteristic diagram showing the shear strength between the iron core and the rotating shaft of the iron core integrated magnet rotor with respect to the heating and hardening temperature. However, the heating time is 1 h load (120 g). As shown, the shear strength increases from the dimensional change rate of 120 ° C to the optimum heating temperature (130 ° C). However, it becomes almost constant at 130-140 ° C. When the regression line is obtained, as shown in the figure, the shear strength at 150 ° C. at which non-uniform hardening due to overheating is recognized in this example starts to decrease. Therefore, the shear strength between the iron core and the rotating shaft of the iron core-integrated magnet rotor matches the optimum heating temperature (130 ° C.) obtained from the dimensional change rate.

Next, FIG. 18 shows the optimum heating temperature (130 ° C.)
FIG. 6 is a characteristic diagram showing the shear strength between the iron core and the rotating shaft of the iron core integrated magnet rotor with respect to the heating time in FIG. However, when the temperature rise inside the iron powder compact (the depth from the surface is 5 to 10 mm) of the actual iron core-integrated magnet rotor was actually measured in this example, it reached 130 ° C. ± 1 deg in 30 minutes after heating. When expressed as the curing time, 3 from the heating time
It is necessary to deduct 0 min. As shown, the shear strength between the iron core and the rotating shaft of the iron core integrated magnet rotor is 130 ° C.
At 15-30 min (heating time 45-60 min). In addition, the shear strength between the iron core of the magnet rotor and the rotating shaft in the optimized hardening is 300 kgf or more, and this level is practically satisfactory.

FIG. 19 is a characteristic diagram showing the influence of the load at the time of heat curing of the iron core integrated magnet rotor under the optimum heating condition of 130 ° C.-1 hr. The shear strength between the iron core and the rotating shaft of the iron core-integrated magnet rotor under the optimized heat curing condition was 300 kgf or more at a load of 320 g (30 g / cm ² or more).

FIG. 20 is a characteristic diagram showing the relation between the shear strength of the iron core of the iron core-integrated magnet rotor and the rotating shaft when the diameter of the rotating shaft is reduced. However, this sample is one in which the iron core and the magnet are integrally rigidified on the rotating shaft, and the structure is different from the ordinary iron core integrated magnet rotor in the present embodiment (actual Equivalent to about half the strength of the integrated magnet rotor). As shown in the figure, the shear strength between the iron core and the rotating shaft decreases as the shaft diameter decreases. However, if the shaft diameter is reduced by about 4 μm, a shear strength of 250 kgf or more can be obtained in the actual iron core integrated magnet rotor.

FIG. 21 is a sectional view of a boundary portion between the iron core and the rotating shaft of the iron core integrated magnet rotor. In the figure, 97 is iron powder,
Reference numeral 98 is an epoxy resin, and 99 is a rotating shaft. FIG.
It can be seen that the epoxy resin 98 forms a discontinuous adhesive layer, as compared with the cross-sectional views of the joint portion between the magnet and the iron core of the iron core integrated magnet rotor shown in (a) and (b).

[DC Relative Permeability of the Iron Core and Magnet] FIG. 22 is a characteristic diagram showing the relationship between the DC Relative Permeability of the iron core and the ratio of the total magnetic flux of the iron-integrated magnet rotor. However, the density of the magnet is 5.
9-6.1 Mg / m ³ , 4 MA / m coercive force after pulse magnetization Hci 636-800 kA / m, maximum energy product (BH) max 76-82 kJ / m ³ , diameter 18
Magnetization of 24 poles on the outer peripheral surface of mm (distance between the poles 2.3 m
m) is applied. In the figure, A is non-magnetic, B is pure iron,
C is prepared by heating and hardening an iron powder compact made from the optimized iron powder compound according to the present invention. The total amount of magnetic flux is standardized by the value of B. As is clear from the figure, the density is 5.0-5.1 Mg / regardless of the method for producing the iron powder (sprayed iron powder, electrolytic iron powder) and the powder particle size.
The direct current relative magnetic permeability of the m ³ iron core is all 10 or more, and the magnetic flux is improved by 50% or more as compared with the pure iron A.

On the other hand, the magnet powder contains α ₂ Fe phase and R ₂ TM ₁₄ B.
In the case of the nanocomposite magnet powder having a phase, the density is 5.9-6.1 Mg / m ³ , the coercive force after pulse magnetization of 4 MA / m Hci550-600 kA / m, and the maximum energy product (BH) max76-82 kJ. / M ³ can be illustrated as an example of a preferable magnet characteristic. In such a magnet, for example, when a magnet having a diameter of 18 mm is magnetized with 48 poles (distance between the poles is 1.2 mm), the magnetizing field is restricted to about 1.2 to 1.6 MA / m. Therefore, the total magnetic flux of the iron core integrated magnet rotor has a density of 5.9-6.1 Mg /
m ³ , 4 MA / m coercive force after pulse magnetization Hci636-
800 kA / m, maximum energy product (BH) max76
This is because the total amount of magnetic flux is improved by 10-20% as compared with the iron core integrated magnet rotor that uses a −82 kJ / m ³ magnet. For the magnet of the iron-core integrated magnet rotor having a distance between the poles of 2 mm or less, it is preferable that the magnet powder contains nanocomposite magnet powder having an αFe phase and an R ₂ TM ₁₄ B phase as a main component.

[0057]

According to the present invention, the thermomechanical load during the manufacture of a magnet rotor is greatly reduced, so that the magnet having a high dimensional accuracy can be obtained without lowering the magnetic characteristics and increasing the wall thickness due to the density of the magnet. A rotor and a permanent magnet type motor using the rotor can be manufactured.

[Brief description of drawings]

FIG. 1 is a process diagram of a conventional technique.

FIG. 2 is a photomicrograph of a cross section of a boundary portion between a magnet and an iron core of a conventional technique.

FIG. 3 is a characteristic diagram showing a relationship between a springback and a shearing force of a conventional technique.

FIG. 4 is a characteristic diagram showing the relationship between magnet density and magnetic characteristics.

FIG. 5 is an external view of a rotor used for a permanent magnet rotor.

FIG. 6 is a schematic diagram showing the role of a powdery latent curing agent.

FIG. 7A is a dimensional diagram of a main part of a magnet powder compacting die. (B) Dimensional drawing of main part of iron powder compact

FIG. 8 is a perspective external view showing a method for manufacturing an iron core integrated magnet rotor.

FIG. 9 is a characteristic diagram showing temperature dependence of bonding strength and expansion coefficient of iron powder compact.

FIG. 10 is a characteristic diagram showing heating temperature dependence of expansion coefficient of axial dimension and magnet diameter.

FIG. 11 is a characteristic diagram showing a dimensional change rate with respect to a load.

FIG. 12 is a characteristic diagram showing the rate of change in rotor diameter and axial dimension with respect to curing time.

FIG. 13 (a) is a micrograph of a cross section of a joint between a magnet and an iron core of an iron core-integrated magnet rotor.

FIG. 14 is a characteristic diagram showing the bonding strength of the iron core-magnet with respect to the amount of epoxy resin of the iron powder compact.

FIG. 15 is a characteristic diagram showing the distribution of epoxy resin from the outer peripheral surface of the iron core to the inner diameter direction.

FIG. 16 is a characteristic diagram showing the amount of epoxy resin on the outer peripheral surface of the iron core.

FIG. 17 is a characteristic diagram showing the heat hardening temperature and the shear strength of the iron core-rotary shaft.

FIG. 18 is a characteristic diagram showing shear strength between an iron core and a rotation axis with respect to heating time.

FIG. 19 is a characteristic diagram showing the relationship between the load during heat curing and the shear strength of the iron core-rotating shaft.

FIG. 20 is a characteristic diagram showing the relationship between the diameter of the rotating shaft and the shear strength of the iron core and the rotating shaft.

FIG. 21 is a micrograph of a cross section of a boundary portion between an iron core and a rotation axis.

FIG. 22 is a characteristic diagram showing the relationship between the magnetic permeability and the ratio of total magnetic flux.

[Explanation of symbols]

1 magnet 2 rotation axes 3 molding materials

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // H01F 1/08 H01F 1/08 AF term (reference) 5E040 AA04 AA11 AA14 AA19 BB03 CA01 HB07 HB17 NN06 5E062 CC05 CD05 CE04 5H002 AA01 AA07 AB01 AC07 5H622 AA03 CA01 CA05 CB06 DD02 PP20 QA02 QA10

Claims (29)

[Claims] 1. A contact surface for contacting a magnet powder compact, an iron powder powder compact, and a rotary shaft by inserting an iron powder powder compact having a rotary shaft into an annular magnet powder compact and heating three members. And a magnet, a powder iron core, and a rotary shaft are simultaneously rigidified integrally by thermosetting an epoxy resin contained in the iron powder green compact. 2. An iron powder compact having an axis of rotation is fixed to an arc-shaped magnet compact, and the magnet powder, iron powder compact and rotary shaft are brought into contact by heating three members. Form the surface,
A method for manufacturing an iron core-integrated magnet rotor in which at least a magnet, a dust core, and a rotating shaft are rigidified simultaneously by thermosetting an epoxy resin contained in at least an iron powder compact. 3. An iron or powder compact having an axis of rotation is inserted into or fixed to an annular or arc-shaped magnet compact, and at least a load of 30 g / cm ² or more is applied to the iron powder compact. The method for manufacturing an iron core integrated magnet rotor according to claim 1 or 2, wherein the magnet, the dust core, and the rotating shaft are rigidified integrally at the same time by heating. 4. An iron powder green compact having a saturation magnetization of 13 kG or more Fe, Fe-Ni, Fe-Co, Fe-Si, Fe-.
A granular compound composed of one or more selected from the group consisting of N and Fe-B, an epoxy resin, and an additive which is appropriately added as necessary, is compression-molded. 2. The method for manufacturing an iron core integrated magnet rotor according to 2. 5. The epoxy resin constituting the iron powder compact is composed of an epoxy oligomer which is solid at room temperature and a powdery latent curing agent, and the content thereof is at least 3 wt. % Or more, the method for manufacturing an iron core integrated magnet rotor according to claim 1 or 2. 6. Iron powder is wet mixed at room temperature with an organic solvent solution of an epoxy oligomer which is solid at room temperature, and the solid block obtained by heating and removing the organic solvent in the wet mixture is crushed and classified into granules. 6. The method for producing an iron core integrated magnet rotor according to claim 5, wherein the iron powder powder compact is formed by powder-molding an iron powder compound obtained by dry-mixing a powdery latent curing agent and an additive that is appropriately added as necessary. 7. The epoxy resin constituting the iron powder compact is an epoxy oligomer which is solid at room temperature, mononuclear spherical microcapsules encapsulating an epoxy oligomer which is liquid at room temperature, and a latent latent curing agent in powder form. Amount of at least 3 wt. % Or more, The manufacturing method of the iron core integrated magnet rotor according to claim 5. 8. A mononuclear spherical microcapsule containing iron powder and an epoxy oligomer which is liquid at room temperature is dry-mixed,
Then, in an organic solvent solution of epoxy oligomer that is solid at room temperature, the mixture of iron powder and microcapsules is wet-mixed at room temperature, and the solid block obtained by heating and removing the organic solvent in the wet mixture is crushed and classified into granules. 3. An iron core integrated magnet according to claim 1 or 2, which is an iron powder green compact finally obtained by dry-mixing an iron powder compound in which a powdery latent curing agent and an additive to be added as required are dry mixed. Method of manufacturing rotor. 9. The upper limit of the particle size of the iron powder compound is 50.
The method for manufacturing an iron core integrated magnet rotor according to claim 6 or claim 8, wherein the magnet rotor has a thickness of 0 μm. 10. The method according to claim 1, wherein a lubricant is an essential component as an additive added to the iron powder compound, and the lubricant is a higher fatty acid or higher fatty acid metal soap having a melting point higher than at least the heat curing temperature of the epoxy resin. 2. The method for manufacturing an iron core integrated magnet rotor according to 2. 11. The method for producing an iron core integrated magnet rotor according to claim 1, which is an iron powder compact obtained by compressing an iron powder compound at a molding pressure of 200 MPa or more. 12. The method of manufacturing an iron core integrated magnet rotor according to claim 1, wherein the porosity of the iron powder compact is 5% or less. 13. The method of manufacturing an iron core integrated magnet rotor according to claim 1, wherein the heating temperature is selected so that the outer diameter of the iron powder compact expands by 0.7% or more before and after heating and hardening. 14. The method of manufacturing an iron core integrated magnet rotor according to claim 1, wherein the density of the powder iron core obtained by heating and hardening the iron powder green compact is 5.0 to 5.1 Mg / m ³ . 15. The direct current relative magnetic permeability of the dust core obtained by heating and hardening the iron powder compact is 1 or more.
A method for manufacturing the iron core-integrated magnet rotor described. 16. The method for producing an iron core integrated magnet rotor according to claim 1, wherein the difference between the inner diameter of the magnet powder compact and the outer diameter of the iron powder compact is 100 μm or less. 17. A magnet powder is wet-mixed at room temperature with an organic solvent solution of an epoxy oligomer which is solid at room temperature, and the solid block from which the organic solvent in the mixture is removed by heating is crushed and classified into granules, and finally A magnet powder compact made by powder-molding a magnet powder compound obtained by dry-mixing a powdery latent curing agent and an additive to be added as necessary. Method. 18. The method for manufacturing an iron core integrated magnet rotor according to claim 17, wherein the upper limit of the particle size of the magnet powder compound is 250 μm. 19. The method according to claim 1, wherein a lubricant is an essential component as an additive to be added to the magnet powder compound, and the lubricant is a higher fatty acid or a higher fatty acid metal soap having a melting point higher than at least the heat curing temperature of the epoxy resin. 2. The method for manufacturing an iron core integrated magnet rotor according to 2. 20. The method of manufacturing an iron core-integrated magnet rotor according to claim 1 or 2, wherein the magnet powder compact and the iron powder compact powder have the same epoxy resin constituent components. 21. The method for producing an iron core integrated magnet rotor according to claim 1, wherein the epoxy resin content of the iron powder compact is 2.5 times or more the epoxy resin content of the magnet compact. . 22. The magnet powder of the magnet powder compact is R-TM-B.
-Based alloy (where R is 10 to 20 at.%, At least one of rare earth elements including Y, TM is Fe or F)
e in which a part of e is replaced by Co, B is 5 to 20 at.
%) The method of manufacturing an iron core integrated magnet rotor according to claim 1 or 2. 23. The method for manufacturing an iron core integrated magnet rotor according to claim 22, wherein the magnet powder is a magnet powder having an R ₂ TM ₁₄ B phase. 24. The magnet has a density of 5.9-6.1 Mg /
m ³ , 4 MA / m coercive force after pulse magnetization Hci636-
800 kA / m, maximum energy product (BH) max76
The method for manufacturing an iron core integrated magnet rotor according to claim 21 or 22, wherein the method has a value of -82 kJ / m ³ . 25. The method of manufacturing an iron core integrated magnet rotor according to claim 24, wherein the outer peripheral surface of the magnet is magnetized at a distance between the poles of 2 mm or more. 26. The magnet powder of the magnet powder compact is αFe phase and R
_The method for producing an iron core-integrated magnet rotor according to claim 1, 2 or 22, which is a nanocomposite magnet powder having a ₂ TM ₁₄ B phase. 27. The magnet has a density of 5.9-6.1 Mg /
m ³ , 4 MA / m coercive force after pulse magnetization Hci550-
600 kA / m, maximum energy product (BH) max76
Core integrated magnet rotor manufacturing method according to any one of claims 1,2,26 a -82kJ / m ^3. 28. The method for manufacturing an iron core integrated magnet rotor according to claim 26, wherein the distance between the magnets is 2 mm or less. 29. A permanent magnet type motor having the magnet rotor according to any one of claims 1, 2, 26, 27 and 28 mounted therein.