JP2009044795A - Permanent magnet embedded motor and method of manufacturing rotor for permanent magnet embedded motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet embedded motor, which improves the productivity and reduces the cost and also uses a permanent magnet of good properties with improved heat resistance, and a method of manufacturing the rotor. <P>SOLUTION: In this permanent magnet embedded motor which comprises a stator equipped with a plurality of coils and a rotor which has a rotor core where each of a plurality of permanent magnets is created in each of a plurality of magnet forming holes and is arranged inside the stator rotatably by a rotating shaft, each of the permanent magnet consists of magnetic powder and coupling materials, and besides each magnetic powder is in contact with the wall face of each magnet forming hole of the rotor core. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a permanent magnet embedded motor used in electrical equipment such as OA equipment and digital equipment, and a method of manufacturing a rotor for a permanent magnet embedded motor.

  Conventionally, permanent magnet type electric motors used for office equipment and household electric appliances are disclosed in JP 2000-37053 A (Patent Document 1) and JP 2002-142392 A (Patent Document 2). A rotor core structure with permanent magnets inserted is used.

  A typical high-performance permanent magnet is a sintered magnet manufactured by sintering a rare earth magnet material. In the rare earth sintered magnet, it is necessary to heat the rare earth magnet material to a high temperature in order to sinter, and the production cost including the equipment cost becomes high. Moreover, the shape and dimension after a sintering process will change with respect to the shape and dimension before a sintering process by the sintering process which heats a magnet material to high temperature. Therefore, in the molding process after the sintering process, a molding operation including a large amount of cutting is required to obtain dimensional accuracy, which is a factor of deterioration in productivity and cost increase.

  Therefore, in recent years, bond magnets obtained by solidifying magnetic powder with resin have begun to be incorporated in motors such as OA equipment and digital equipment that do not require as high output as sintered magnets. This bonded magnet is disclosed in JP-A-11-238640 (Patent Document 3), JP-A-11-067514 (Patent Document 4) and JP-A-10-208919 (Patent Document 5). A magnet obtained by mixing a thermosetting epoxy resin and magnetic powder and molding the mixture, and bonding the magnetic powder with an epoxy resin. Therefore, since it can be formed into a shape to be inserted into the core, the productivity is higher than that of the sintered magnet, and the cost can be reduced because a sintering step is unnecessary. Patent Documents 3 to 5 further disclose techniques relating to improvement of magnetic characteristics and the like in the bonded magnet.

JP 2000-37053 A JP 2002-142392 A Japanese Patent Laid-Open No. 11-238640 Japanese Patent Laid-Open No. 11-067514 Japanese Patent Laid-Open No. 10-208919

  However, in the bonded magnet using the epoxy resin described in Patent Documents 3 to 5 as a binder, the ratio of the epoxy resin material to the magnetic powder increases, and the ratio of the magnetic powder to the magnet decreases. It is not possible to produce a magnet-embedded motor with poor characteristics and good characteristics. In addition, when the binder is an epoxy resin, the heat resistance is inferior to the sintered magnets described in Patent Documents 1 and 2, and the binder cannot be used in an environment of 150 ° C. or higher.

  In view of the above problems, the object of the present invention is to improve productivity and reduce costs further than conventional bonded magnets, and have superior magnetic properties and improved heat resistance even in an environment of 150 ° C. or higher. It is an object of the present invention to provide a permanent magnet embedded motor having a usable rotor and a method of manufacturing a rotor for a permanent magnet embedded motor.

  Another object of the present invention is to provide electrical equipment such as OA equipment and digital equipment provided with the permanent magnet embedded motor.

  In order to solve the above-mentioned problem, the first feature of the present invention is that the rotor core is formed by filling the magnetic powder into the magnet forming hole of the rotor core and then forming the magnet by compression molding. There is to configure.

  In addition, the second feature of the present invention is that the voids of the magnetic powder compression molded body formed by compression molding in the magnet forming hole of the rotor core are impregnated with a precursor solution of an inorganic material, followed by heat treatment. This is to secure heat resistance by using a binder of an inorganic material.

  The third feature of the present invention is that the magnetic powder is compression-molded in the magnet formation hole of the rotor core, and the magnetic powder is filled with high density because a small amount of binder is required. Thus, it is possible to produce a permanent magnet with good characteristics.

  That is, the present invention has a stator having a plurality of windings and a rotor core in which each of a plurality of permanent magnets is formed in each of a plurality of magnet forming holes, and is rotated by a rotating shaft inside the stator. A permanent magnet embedded motor including a rotor arranged in a possible manner, wherein each of the permanent magnets is made of a magnetic powder and a binder, and each magnetic powder is a magnet forming hole of the rotor core. It is in contact with the wall surface.

  Further, the present invention is characterized in that each of the permanent magnets is formed in each magnet forming hole by compression-molding each magnetic powder. The present invention is also characterized in that the cross-sectional shape of each of the permanent magnets in a direction perpendicular to the rotation axis of the rotor is substantially rectangular or arcuate. Further, the present invention is characterized in that the binder is an inorganic material. In the invention, it is preferable that the magnetic powder is a rare earth.

  The present invention also includes a filling step of filling each of the plurality of magnet forming holes formed in the rotor core with magnetic powder, and compression molding the magnetic powder filled in each of the magnet forming holes by the filling step. A compression molding step of forming each of the magnet forming holes as a magnetic powder body, an impregnation step of impregnating each magnetic powder body compression molded in the compression molding step with a precursor solution of a binder, and the impregnation step A heat treatment step of fixing each of the magnetic powder bodies impregnated with the precursor solution of the binder by heat treatment and fixing the magnet to each of the magnet formation holes, and each of the magnet formation holes in the heat treatment step. And a magnetizing step for magnetizing a fixed magnet. A method of manufacturing a rotor for a permanent magnet embedded motor.

  Further, the present invention provides a filling step of filling each of the plurality of magnet forming holes formed in the rotor core with magnetic powder, and a binder to the magnetic powder filled in each of the magnet forming holes by the filling step. An addition step of adding the precursor solution, and a precursor solution of the binder is added by the addition step, and the magnetic powder filled in each of the magnet forming holes is compression-molded to form the magnet as a magnetic powder body A compression molding step for forming each of the formation holes, a heat treatment step for fixing each magnet powder body compression-molded in the compression molding step by heat treatment, and fixing the magnets to each of the magnet formation holes, and the heat treatment step. And a magnetizing step of magnetizing a magnet fixed to each of the magnet forming holes. A method of manufacturing a rotor for an embedded permanent magnet motor.

  The present invention further includes a preparation step of preparing the rotor core by laminating disc-shaped electromagnetic steel plates in which a plurality of magnet forming holes are formed. In the present invention, the magnetic powder to be filled in the filling step is a plate-like powder.

  ADVANTAGE OF THE INVENTION According to this invention, while improving productivity and cost reduction, the permanent magnet embedded type motor using the permanent magnet with the favorable characteristic which also improved heat resistance is realizable.

  Further, according to the present invention, it is possible to realize an electrical device such as an OA device or a digital device provided with a permanent magnet embedded motor.

  Embodiments of an embedded permanent magnet motor according to the present invention, a method for manufacturing the same, and electrical equipment such as OA equipment and digital equipment provided with the motor will be described with reference to the drawings.

  An embodiment of a method for manufacturing a rotor core constituting an embedded permanent magnet motor, which is a feature of the method for manufacturing an embedded permanent magnet motor according to the present invention, will be described with reference to FIGS.

  FIG. 1 is a diagram showing a first embodiment of a method for manufacturing a permanent magnet (magnetic powder compression molding) on a rotor core constituting a permanent magnet embedded motor according to the present invention. FIG. 2 is a diagram showing a second embodiment of a method for producing a permanent magnet (magnetic powder compression molded body) on a rotor core constituting the embedded permanent magnet motor according to the present invention. FIG. 3 is a top view showing a first embodiment of a rotor core according to the present invention. FIG. 4 is a top view showing a second embodiment of the rotor core according to the present invention. FIG. 5 is a cross-sectional view taken along arrows 3A-A and 4B-B showing one embodiment of a process for forming a magnetic powder compression molded body in each magnet-forming hole formed in the rotor core according to the present invention. It is.

  First, the rotor core 1 formed by laminating disc-shaped electromagnetic steel plates (for example, silicon steel plates) in which the magnet forming holes 4 are formed is prepared. Next, as shown in FIG. 5, the prepared rotor core 1 is placed on the upper guide 8 and the upper guide portion 20 in the state where the axial direction of the shaft hole 3 of the rotor core 1 is substantially vertical. Set between the guide 7. Next, for example, the magnetic powder is filled into each magnet forming hole 4 of the rotor core 1 through the punch hole 9 formed in the upper guide 7 with the upper punch 5 raised (S11). Thereafter, the magnetic powder filled in each magnet forming hole 4 is compression-molded by the press device 20 including the upper punch 5 and the lower punch 6 (S12). In this compression molding step S12, the density of the magnetic powder compression molded body 10 is 2.5 to 3 times the powder packing density, that is, the height is 1 / 2.5 to 1/3. Therefore, in order to perform compression molding at a time, it is necessary to provide and pressurize at least the upper guide portion 7 for supplying a necessary amount of powder to the upper portion of each magnet forming hole 4. When the magnetic powder is filled into each magnet forming hole 4 through each punch hole 9 formed in the upper guide 7 with the lower punch 6 raised to some extent, when the filled magnetic powder is compression molded. The lower punch 6 does not necessarily have to be raised.

  Subsequently, the compression molded magnetic powder body 10 is sufficiently impregnated with a precursor solution of a binder having excellent wettability with this material (S13). Then, heat treatment is performed so that the magnet 2 bound with the magnetic powder is formed (embedded) in each magnet forming hole 4 in a state where the magnetic powder is in contact (adhered) to the wall surface of each magnet forming hole 4 of the rotor core 1. To be fixed (S14). In addition, although it is the packing density of the magnetic powder of the compression molding manufactured as mentioned above, since the fluidity is required at the time of shaping | molding with a bonded magnet, since the resin material is required more than 25 vol%, the packing density of magnetic powder is Whereas the maximum is about 75 vol%, in the present invention, only the magnetic powder is compression-molded, so the filling density of the magnetic powder depends on the pressure at the time of compression molding, but can be up to about 90%. This is inferior to the packing density of the magnet powder of the sintered magnet being about 100%. However, it is possible to fill the magnet forming hole 4 without gaps through the punch holes (filling openings) 9 of the upper guide 7 and increase the volume of the magnetic powder molding part 10 so that the magnet has the same degree of magnetism as the sintered magnet. It is possible to obtain characteristics. Further, according to the present invention, since it is possible to directly form the portion of the magnet forming hole 4 of the rotor core 1, the magnet can be easily formed into a curved shape that requires cutting with a sintered magnet. It becomes possible to mold into.

  In addition, according to the present invention, the magnetic powder compact 10 after compression molding is impregnated with the precursor solution of the binder, so that the magnetic powder compact is formed on the wall of the magnet forming hole 4 simultaneously with the binding of the magnetic powder. Since 10 can be bonded at the same time, workability is improved. As shown in FIG. 2, the binder precursor solution may be dropped (added) after powder filling and then compression molded. That is, the second embodiment shown in FIG. 2 is different from the first embodiment in which impregnation with a binder precursor solution (S13) is performed after pressure molding (S12) as shown in FIG. Then, after adding (dropping) the binder precursor solution (S13 ′), pressure molding (S12) is performed.

  Subsequently, a magnetizing step is required to make the bound magnetic powder compression molded body a permanent magnet. In the magnetizing step (S15), the magnetic powder compression molded body 10 becomes a permanent magnet by magnetizing the rotor core in which the bound magnetic powder compression molded body 10 is incorporated.

In the present invention, a plate shape is suitable as the shape of the magnetic material powder suitable for compression molding at high pressure. That is, the greater the pressure applied during compression molding, the higher the density of the molded body, but the shape of the magnetic powder at that time, the better the fluidity of the particles, the closer to a cube or spherical shape, The same pressure is applied in the direction perpendicular to the pressurizing direction. On the other hand, in the case of plate-like particles, when the plate-like surfaces are aligned in a direction perpendicular to the pressurizing direction, the movement of the particles in the direction perpendicular to the pressurizing direction is limited, so the stress in the direction perpendicular to the pressurizing direction is small. Become. That is, as the plate shape is increased, the molding pressure within a range where the rotor core is not deformed can be increased, so that the packing density can be further increased. Summary of the magnetic powder filling rate for the compressive force of about 75 vol% at 5 ton / cm ^2, about 80 vol% in 10ton / cm ^2, the 85～90Vol% approximately in 20ton / cm ² or more. Specifically, the pressing force at the time of compression molding may be a maximum pressure that does not deform the rotor core. In the case of a silicon steel plate that is a general rotor constituent material, a plate-like magnetic powder material was used. In this case, 5 to 15 ton / cm ² is suitable as the compression molding pressure, but when the entire rotor core is placed in a mold (not shown) at the time of compression molding, deformation of the outer diameter and inner diameter of the rotor core can be suppressed. The pressure may be about 20 ton / cm ² . At the time of these high-pressure moldings, the magnetic powder is sunk into the wall surface of the magnet forming hole 4 of the rotor core 1 by pressurization, and the compression molded body 10 is fixed to the wall surface of the magnet forming hole 4.

  The magnetic powder and precursor solution suitable for the present invention will be described below. As a magnetic powder suitable for the compression molding, for example, in the form of the present invention, a non-oxide magnetic powder is used, and in particular, a plate-like shape manufactured by quenching a mother alloy such as a rare earth magnet, for example, NdFeB, is formed. In addition, the X-axis and Y-axis directions are several times larger than the value in the Z-axis direction, which is the height direction, and the thickness is about 30 microns. Although it is unavoidable that the powder becomes fine due to cracking by compression and the powder having a small shape is mixed, for example, using a large powder in the X-axis or Y-axis direction of the powder improves the residual characteristics.

In addition, as long as the precursor solution can be cured at a relatively low temperature, even when non-oxide magnetic powder is used, it is possible to suppress the oxidation of the magnetic powder and obtain a magnet having high magnetic properties. As the precursor solution of the binder, for example, a compound having an alkoxysiloxane or alkoxysilane which is a precursor of SiO ₂ and having an alkoxy group in the terminal group and side chain as shown in Chemical Formula 1 or Chemical Formula 2 have.

また、溶媒のアルコールにはアルコキシシロキサン、アルコキシシラン中のアルコキシ基と同じ骨格の化合物が好ましいがこれらに限られるものではない。具体的にはメタノール、エタノール、プロパノール、イソプロパノール等が挙げられる。また、加水分解及び脱水縮合用触媒としては酸触媒、塩基触媒、中性触媒のいずれでも良いが中性触媒が金属の腐食を最小限に抑えられるので最も好ましい。中性触媒としては、オルガノスズ触媒が効果的で、具体的にはビス（２−エチルヘキサノエート）スズ、ｎ−ブチルトリス（２−エチルヘキサノエート）スズ、ジ−ｎ−ブチルビス（２−エチルヘキサノエート）スズ、ジ−ｎ−ブチルビス（２，４−ペンタンジオネート）スズ、ジ−ｎ−ブチルジラウリルスズ、ジメチルジネオデカノエートスズ、ジオクチルジラリル酸スズ、ジオクチルジネオデカノエートスズ等が挙げられるがこれらに限られるものではない。また、酸触媒としては希塩酸、希硫酸、希硝酸、蟻酸、酢酸等が、塩基触媒としては水酸化ナトリウム、水酸化カリウム、アンモニア水等が挙げられるがこれらに限られるものではない。

Further, the alcohol of the solvent is preferably a compound having the same skeleton as the alkoxy group in alkoxysiloxane or alkoxysilane, but is not limited thereto. Specific examples include methanol, ethanol, propanol, isopropanol and the like. Further, the catalyst for hydrolysis and dehydration condensation may be any of an acid catalyst, a base catalyst, and a neutral catalyst, but the neutral catalyst is most preferable because corrosion of the metal can be minimized. As the neutral catalyst, an organotin catalyst is effective. Specifically, bis (2-ethylhexanoate) tin, n-butyltris (2-ethylhexanoate) tin, di-n-butylbis (2-ethyl) Hexanoate) tin, di-n-butyl bis (2,4-pentanedionate) tin, di-n-butyl dilauryl tin, dimethyl dineodecanoate tin, dioctyl dilarylate tin, dioctyl dineodecano Examples include, but are not limited to, ate tin. Examples of the acid catalyst include dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, formic acid, acetic acid, and the like, and examples of the base catalyst include sodium hydroxide, potassium hydroxide, aqueous ammonia, and the like, but are not limited thereto.

The total content of alkoxysiloxane, alkoxysilane, its hydrolysis product, and its dehydration condensate, which is a precursor of SiO _{2 in} the binder solution, is preferably 5 vol% or more and 96 vol% or less. When the total content of alkoxysiloxane, alkoxysilane, its hydrolysis product, and its dehydration condensate is less than 5 vol%, the binder content in the magnet is low. The strength of is slightly reduced. On the other hand, alkoxysiloxane, alkoxysilane, hydrolysis product thereof, and when the content of dehydrated condensates total is more than 96 vol%, alkoxysiloxane that is a precursor of SiO _2, the fast reaction of the molecular weight of the alkoxysilane Therefore, the thickening speed of the binder solution is also increased. This means that it is more difficult to control the proper viscosity of the binder solution, and it becomes more difficult to use this binder solution for the impregnation method than the materials described above.

The alkoxysiloxane or alkoxysilane and water is a precursor of SiO ₂ of the binder solution, the following chemical formula 3, hydrolysis reaction occurs as shown in Formula 4. Here, the chemical reaction formula is a reaction formula when hydrolysis partially occurs.

この際、水の添加量がアルコキシシロキサン又はアルコキシシランの加水分解反応の進行度を支配する因子の一つとなる。この加水分解反応は硬化後の結着剤の機械的強度が大きくするためには重要である。アルコキシシロキサン又はアルコキシシランの加水分解反応が発生していないと、その次に起こるアルコキシシロキサン又はアルコキシシランの加水分解反応物同士の脱水縮合反応が進行しないからである。この脱水縮合反応生成物がＳｉＯ_２であり、このＳｉＯ_２が磁粉との接着性が高く、結着剤の機械的強度を大きくする重要な材料となるからである。更に、シラノールのＯＨ基が磁粉表面のＯ原子又はＯＨ基と相互作用が強く高接着化に寄与するからである。しかしながら、加水分解反応が進みシラノール基の濃度が高くなるとシラノール基を含む有機ケイ素化合物（アルコキシシロキサン又はアルコキシシランの加水分解生成物）同士の脱水縮合反応が進行し、有機ケイ素化合物の分子量が大きくなり、結着剤の溶液の粘度は高くなる。これは含浸法に用いる結着剤の溶液としては適正な状態が遠ざかる特性である。従って、結着剤溶液中のＳｉＯ_２の前駆体であるアルコキシシロキサン又はアルコキシシランに対する適正な水の添加量が必要となる。

At this time, the amount of water added is one of the factors governing the progress of the hydrolysis reaction of alkoxysiloxane or alkoxysilane. This hydrolysis reaction is important for increasing the mechanical strength of the binder after curing. This is because if the hydrolysis reaction of alkoxysiloxane or alkoxysilane does not occur, the dehydration condensation reaction between the alkoxysiloxane or alkoxysilane hydrolysis reaction products that occurs next does not proceed. This is because the dehydration condensation reaction product is SiO ₂ , and this SiO ₂ has high adhesiveness with the magnetic powder and becomes an important material for increasing the mechanical strength of the binder. Furthermore, the OH group of silanol has a strong interaction with the O atom or OH group on the surface of the magnetic powder and contributes to high adhesion. However, when the hydrolysis reaction proceeds and the concentration of silanol groups increases, dehydration condensation reaction between organosilicon compounds containing silanol groups (alkoxysiloxane or alkoxysilane hydrolysis products) proceeds, and the molecular weight of the organosilicon compounds increases. The viscosity of the binder solution increases. This is a characteristic that an appropriate state of the binder solution used in the impregnation method is not suitable. Accordingly, it is necessary to add an appropriate amount of water to the alkoxysiloxane or alkoxysilane that is the precursor of SiO _{2 in} the binder solution.

Here, the addition amount of water in the insulating layer forming treatment liquid is preferably 1/10 to 1 of the reaction equivalent in the hydrolysis reaction shown in Chemical Formula 3 and Chemical Formula 4 above. When the amount of water added is 1/10 or less of the reaction equivalent in the hydrolysis reactions shown in Chemical Formula 3 and Chemical Formula 4, the concentration of silanol groups in the organosilicon compound is low. low interaction, but also, because the alkoxy group in the product for dehydration condensation reaction is hard to occur to produce SiO ₂ is that a large amount of remaining defect is generated number in SiO _2, the strength of the SiO ₂ is low Become. On the other hand, when the amount of water added is greater than 1 of the reaction equivalent in the hydrolysis reactions shown in Chemical Formula 3 and Chemical Formula 4, the organosilicon compound containing a silanol group is likely to undergo dehydration condensation and the binder solution increases. Since it is viscous, the binder solution cannot penetrate into the gap between the magnetic powder and the magnetic powder, and the binder solution used in the impregnation method has a characteristic of moving away from an appropriate state. Alcohol is usually used as the solvent in the binder solution. This is because the alkoxy group in the alkoxysiloxane has a fast dissociation reaction in the solvent used for the binder solution, and is in equilibrium with the solvent alcohol. Therefore, methanol, ethanol, n-propanol, and iso-propanol having a boiling point lower than that of water and low viscosity are preferable as the solvent alcohol. However, although the stability of the solution is slightly decreased chemically, the viscosity of the binder solution does not increase in a few hours and the solvent of the present invention has a lower boiling point than water. Any water-soluble solvent such as ketones such as acetone can be used.

  Next, a configuration using an oxide glass material other than SiO-based as a binder will be examined. As described above, various requirements are imposed on the precursor as the impregnation solution in order to perform the manufacturing process of the present invention. It has a low viscosity, high permeability, high stability, and curing at a relatively low temperature. It has been confirmed that the SiO-based binder is the best for satisfying these requirements, but other oxide glassy materials can be used as binders if the requirements suitable for this production process are satisfied. However, a certain degree of effect can be expected.

  As described above, according to the embodiment of the present invention, a rotor core 1 in which a plurality of permanent magnets 2 are embedded is created, and a rotary shaft ( A permanent magnet according to the present invention is manufactured by press-fitting a rotor (not shown) and manufacturing the rotor, and rotatably installing the manufactured rotor inside a stator (not shown) having a plurality of windings. The embedded motor will be completed.

  Furthermore, according to the embodiment of the present invention, it is possible to realize an electrical device such as an OA device or a digital device provided with a completed permanent magnet embedded motor.

  Next, the results of manufacturing and evaluating the embedded permanent magnet motor according to the present invention will be described.

[First embodiment]
In the first embodiment, magnetic powder compression molding at the rotor magnet portion and motor characteristic evaluation were performed. As the magnetic powder for rare earth magnets, magnetic powder obtained by pulverizing NdFeB-based ribbons prepared by quenching a mother alloy having a adjusted composition was used. The NdFeB-based master alloy is made uniform by mixing Nd with iron or an Fe-B alloy (ferroboron) and dissolving it in a vacuum, an inert gas or a reducing gas atmosphere. If necessary, the master alloy cut by a single roll or twin roll method is used, and the master alloy dissolved on the surface of the rotating roll is injected and quenched in an inert or reducing gas atmosphere such as argon gas. After forming the ribbon, heat treatment is performed in an inert gas or a reducing gas atmosphere. The heat treatment temperature is 200 ° C. or higher and 700 ° C. or lower, and Nd ₂ Fe ₁₄ B crystallites grow by this heat treatment. The ribbon is 10 μm or more and 50 μm or less in thickness. In this example, NdFeB-based magnetic powder having a high residual magnetic flux density (residual magnetic flux density of 0.7 T to 1.4 T and coercive force of 10 kOe to 30 kOe) was prepared.

First, the rotor core 1 in which the magnet formation hole 4 is formed is prepared. FIG. 3 shows a top view of the rotor core, and the rotor core 1 is formed by laminating disc-shaped electromagnetic steel plates (for example, silicon steel plates). Subsequently, as shown in FIG. 5, the rotor core 1 is set in the press device 20 in a direction in which the rotation center axis direction of the rotor core 1 is vertical. At this time, after setting so that the powder filling guide portions 7 and 8 are in close contact with the magnet forming hole 4 portion, a predetermined amount of magnetic powder is put into the magnet forming hole using the punch hole (supply opening) 9 of the upper guide portion 7. The portion 4 is filled (S11). Subsequently, as shown in FIG. 1, the rotor core 1 is formed by compressing the filled magnetic powder at a pressure of 20 ton / cm ² using a press device 20 that presses the upper punch 5 against the lower punch 6. The compression molded body 10 is formed in the magnet forming hole 4 (S12). Then, the rotor core 1 in which the magnetic powder compact 10 is in close contact with the rotor magnet portion by compression molding is removed from the press device 20, and a precursor solution that becomes SiO ₂ is dropped into the compression magnetic powder portion and vacuumed. After being impregnated sufficiently (S13), after the impregnation, the solvent is evaporated in a vacuum atmosphere and a heat treatment is performed at 170 ° C. for 30 minutes, whereby a magnetic powder compression molded body 10 bound with SiO ₂ is obtained as a magnet. The magnetic powder is embedded and fixed in each magnet forming hole 4 in a state where the magnetic powder is in contact (adhered) to the wall surface of the forming hole 4 (S14). Thereafter, by applying a pulse magnetic field of 30 kOe or more, the permanent magnet 2 was formed by magnetizing the magnetic powder embedded and fixed in each magnet forming hole 4 (S15). In the first embodiment, CH ₃ O— (Si (CH ₃ O) ₂ —O) _m —CH ₃ (m is 3 to 5, average is 4 as the precursor solution to be impregnated into the magnetic powder part. ) Was mixed with 5 ml of water, 0.96 ml of water, 95 ml of dehydrated methyl alcohol and 0.05 ml of dibutyltin dilaurate, and a precursor solution which was allowed to stand at a temperature of 25 ° C. for 2 days was used.

  The magnetic powder filling density thus obtained was 85 vol% or more, which was about 15% higher than 75 vol% of the bonded magnet, and could be used at an environmental temperature of 150 ° C.

[Second Embodiment]
In the first embodiment, as shown in FIG. 1, the precursor solution to be SiO ₂ was dropped after compression molding of the magnetic powder, but in the second embodiment, a predetermined amount of magnetic powder was filled as shown in FIG. Thereafter, the precursor solution was dropped (added) (S13 ′) and compression-molded by the press machine 20 (S12). Subsequently, the rotor core 1 is removed from the press device 20, the solvent is evaporated in a vacuum atmosphere, and heat treatment at 170 ° C. for 30 minutes is performed to obtain the magnetic powder compact 10 bound with SiO ₂ . Thereafter, similarly to the first embodiment, the permanent magnet 2 was formed by magnetizing the magnetic powder embedded and fixed in each magnet forming hole 4 (S15).

  As described above, the magnetic powder packing density of the second embodiment was 85 vol% or more as in the first embodiment, which was about 15% higher than that of the bonded magnet, and an environmental temperature of 150%. It was possible to use at ℃.

[Third embodiment]
In the first and second embodiments, the shape of the magnet forming hole 4 is rectangular as shown in FIG. 3, but in the third embodiment, the shape of the magnet forming hole 4 is shown in FIG. A magnetic powder compression molded body 10 is formed on the rotor core 1 in the same manner as in the first embodiment, and the magnetic powder is embedded and fixed in each magnet forming hole 4. The permanent magnet 2 was formed by performing the above magnetization, and the rotor core for a permanent magnet embedded motor according to the present invention was produced.

  Thus, the magnetic powder packing density of the product manufactured in the third example was 85 vol% or more as in the first example, which was improved by about 15% compared to 75 vol% of the bonded magnet, and the ambient temperature was 150 It was possible to use at ℃.

  A rotor is manufactured by press-fitting a rotation shaft (not shown) into the shaft hole 3 of the rotor core 1 embedded with the plurality of permanent magnets 2 produced according to the first to third embodiments described above. By installing the manufactured rotor in a rotatable manner inside a stator (not shown) having a plurality of windings, a permanent magnet embedded motor according to the present invention is completed.

  ADVANTAGE OF THE INVENTION According to this invention, while improving productivity and cost reduction, while providing the permanent magnet motor using the permanent magnet of the characteristic with the improved heat resistance, OA using this can be provided. Equipment and digital equipment can be provided.

It is a figure which shows the manufacturing process of the magnetic powder compression molding body in 1st Embodiment based on this invention. It is a figure which shows the manufacturing process of the magnetic powder compression molding body in 2nd Embodiment based on this invention. It is a top view which shows the 1st Example of the rotor part of the permanent magnet embedded type motor which concerns on this invention. It is a top view which shows the 2nd Example of the rotor part of the permanent magnet embedded type motor which concerns on this invention. 3A and 3B are sectional views showing one embodiment of a process for forming a magnetic powder compression molded body in each magnet forming hole formed in the rotor core according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Rotor core, 2 ... Permanent magnet, 3 ... Shaft hole, 4 ... Magnet formation hole, 5 ... Upper punch, 6 ... Lower punch, 7 ... Filling guide part (upper guide part), 8 ... Filling guide part (lower) Guide part), 9 ... Punch hole (filling opening), 10 ... Magnetic powder compression molding, 20 ... Press apparatus.

Claims (11)

A stator provided with a plurality of windings and a rotor core in which each of a plurality of permanent magnets is formed in each of a plurality of magnet formation holes, and a rotation arranged rotatably around a rotating shaft inside the stator A permanent magnet embedded motor with a child,
Each of the permanent magnets is made of a magnetic powder and a binder, and each magnetic powder is in contact with the wall surface of each magnet forming hole of the rotor core.   The permanent magnet embedded motor according to claim 1, wherein each of the permanent magnets is formed in each magnet forming hole by compressing and molding each magnetic powder.   3. The embedded permanent magnet motor according to claim 1, wherein a cross-sectional shape of each of the permanent magnets in a direction perpendicular to the rotation axis of the rotor is substantially rectangular or arcuate.   The permanent magnet embedded motor according to claim 1, wherein the binding material is an inorganic material.   The permanent magnet embedded motor according to claim 1, wherein the magnetic powder is a rare earth. A filling step of filling each of a plurality of magnet forming holes formed in the rotor core with magnetic powder;
A compression molding step of compression-molding the magnetic powder filled in each of the magnet-forming holes by the filling step to form each of the magnet-forming holes as a magnetic powder body;
An impregnation step of impregnating each magnetic powder body compression molded in the compression molding step with a precursor solution of a binder;
A heat treatment step of fixing each of the magnetic powder bodies impregnated with the precursor solution of the binder in the impregnation step by heat treatment and fixing the magnet to each of the magnet formation holes;
And a magnetizing step of magnetizing a magnet fixed to each of the magnet forming holes in the heat treatment step. A method of manufacturing a rotor for an embedded permanent magnet motor, comprising: A filling step of filling each of a plurality of magnet forming holes formed in the rotor core with magnetic powder;
An addition step of adding a precursor solution of a binder to the magnetic powder filled in each of the magnet forming holes by the filling step;
A compression molding step in which the precursor solution of the binder is added in the addition step, and the magnetic powder filled in each of the magnet formation holes is compression molded to form a magnetic powder body in each of the magnet formation holes; ,
A heat treatment step of fixing the magnets bonded by heat treatment of the magnetic powder bodies compression-molded in the compression-molding step to each of the magnet formation holes;
And a magnetizing step of magnetizing a magnet fixed to each of the magnet forming holes in the heat treatment step. A method of manufacturing a rotor for an embedded permanent magnet motor, comprising:   The embedded permanent magnet according to claim 6, further comprising a preparation step of preparing the rotor core by laminating disc-shaped electromagnetic steel plates formed with a plurality of magnet forming holes. A method of manufacturing a rotor for a motor.   The method of manufacturing a rotor for a permanent magnet embedded motor according to claim 6 or 7, wherein the magnetic powder to be filled in the filling step is a plate-like powder.   The method for manufacturing a rotor for a permanent magnet embedded motor according to claim 6, wherein the magnetic powder is a rare earth.   The method for manufacturing a rotor for a permanent magnet embedded motor according to claim 6 or 7, wherein the binder is formed of an inorganic material.

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