JP3588692B2 - Permanent magnet synchronous motor magnet - Google Patents
Permanent magnet synchronous motor magnet Download PDFInfo
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- JP3588692B2 JP3588692B2 JP05826598A JP5826598A JP3588692B2 JP 3588692 B2 JP3588692 B2 JP 3588692B2 JP 05826598 A JP05826598 A JP 05826598A JP 5826598 A JP5826598 A JP 5826598A JP 3588692 B2 JP3588692 B2 JP 3588692B2
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- Prior art keywords
- magnet
- temperature
- synchronous motor
- coercive force
- permanent magnet
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
- H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
- H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
- H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
- H01F1/047—Alloys characterised by their composition
- H01F1/053—Alloys characterised by their composition containing rare earth metals
- H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
Description
【０００１】
【発明の属する技術分野】
本発明は、永久磁石（ＰＭ）同期モータに用いる磁石材料に関する。
【０００２】
【従来の技術】
永久磁石（ＰＭ）同期モータは、高効率、高出力密度の点から、電気自動車又はハイブリッド電気自動車の駆動用モータとして注目され、これを用いた自動車が多数開発されている。
【０００３】
ＰＭ同期モータの出力は、内部の永久磁石材料の特性に直接依存するため、実用上、単位体積当たりのエネルギー積の最も大きなＮｄ−Ｆｅ−Ｂ系磁石が採用されるケースが多い。また、モータはその構成上、コイルに電流を流して磁界を発生させ、その磁界と永久磁石の吸引を利用して回転力を得るため、モータ動作に伴って、コイルから熱が発生する。
【０００４】
ところが、上述の永久磁石として用いられているＮｄ−Ｆｅ−Ｂ系磁石は、温度上昇に伴う保磁力の低下率が大きく、動作中に磁石性能が損なわれること（減磁）が大きな問題となっている。減磁を軽減するためには、一般的には磁石の保磁力そのものを増大させて、高温に至っても十分な保磁力を維持する目的で、Ｄｙ，Ｃｏなどの添加がなされている。
【０００５】
【発明が解決しようとする課題】
しかしながら、このような従来の永久磁石（ＰＭ）同期モータ用磁石にあっては、保磁力の温度上昇に伴う低下率、すなわち保磁力の温度係数は−０．６％／℃程度と依然として大きいため、動作中に磁石性能が損なわれるという問題があり、本質的には、温度係数を改善（温度係数の絶対値の減少）して、磁石の使用限界温度を向上させる必要がある。
そこで、Ｎｄ−Ｆｅ−Ｂ系磁石の保磁力温度係数を改善（温度係数の絶対値の減少）することにより、Ｎｄ−Ｆｅ−Ｂ系磁石の使用限界温度を向上させることが課題となっていた。
【０００６】
本発明は、このような従来の問題点に着目してなされたもので、より高温環境下でのモータ動作が可能な永久磁石（ＰＭ）同期モータ用磁石を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明は上述の課題を解決するために、その構成を、Ｎｄ，Ｄｙ，Ｆｅ，Ｃｏ及びＢを主成分とする磁石材料又はＮｄ，Ｆｅ，Ｃｏ及びＢを主成分とする磁石材料において、Ｓｉ及びＣを主相であるＮｄ ２ Ｆｅ １７ Ｂ相に一定量固溶させた永久磁石（ＰＭ）同期モータ用磁石とすることにより、上記問題点を解決するものである。
【０００８】
以下、本発明の作用を説明する。
本発明による磁石では、主相であるＮｄ２ Ｆｅ１７Ｂ結晶中にＳｉとＣが固溶することにより、結晶磁気異方性の温度特性が改善されるために、保磁力の温度係数の絶対値が減少し、温度上昇に伴う保磁力の減少度合いを低く抑えられる。
これにより、磁石の使用限界温度が従来に比べて飛躍的に向上し、より高温の状態でモータを動作させることが可能となる。
【０００９】
【発明の実施の形態】
以下、本発明による永久磁石（ＰＭ）同期モータ用磁石の具体的構成について、詳細に説明する。
本発明で用いるＮｄ−Ｆｅ−Ｂ系磁石材料は、主成分としては、公知のＮｄ２ Ｆｅ１４Ｂ系化合物であり、その保磁力の温度特性改善（保磁力の温度係数の絶対値の減少）のために、ＳｉとＣを同時に添加したものである。
【００１０】
これらの磁石材料は、公知の粉末冶金法、液体急冷法などにより製造され、磁石の限界使用温度が向上するため、これを用いたモータは、従来より高温の状態で動作させることが可能となる。
【００１１】
本発明による磁石材料中のＳｉ及びＣは、その全て又は一部が主相であるＮｄ２ Ｆｅ１７Ｂ相に固溶し、結晶格子の歪み又は元素同士の磁気的結合状態を変化させるため、主相の結晶磁気異方性の温度依存性に影響を与えるものと考えられる。これにより、磁石の保磁力は、温度上昇に伴う低下を低く抑えることができるため、より高温まで磁石を使用することが可能となる。
【００１２】
また、ＳｉとＣの添加量と保磁力の温度係数の変化を検討した結果、両元素とも、０．０５原子％以上の添加において、その効果（温度係数の絶対値の減少）が顕著に現れ始める。さらに添加量を増やした場合は、２．０原子％以上において、保磁力の温度係数は、添加前に比べて改善（温度係数の絶対値の減少）されているが、磁石の磁束密度の低下が著しい。そのため、ＳｉとＣの添加量としては、０．０５〜２．０原子％が好ましい。
【００１３】
以下、本発明の具体的実験例を示し、本発明をさらに詳細に説明する。
【００１４】
＜実験例１＞
粉末冶金法にて製造した種々の焼結磁石における保磁力の温度係数を、表１に示した。
それぞれの磁石の元素組成は、（Ｎｄ１３Ｄｙ２ Ｆｅ７３Ｃｏ５ Ｂ７ ）１００−ｘ−ｙ Ｓｉｘ Ｃｙ において、ｘとｙを変化させたものである。
【００１５】
所定の割合に秤量された各金属を高周波溶解し、粒径３〜５μｍに粉砕した合金粉末を、２５ｋＯｅの磁場中でプレス圧２ｋｇｆ／ｃｍ２ でプレスして、圧粉体を形成した。これらの圧粉体を、真空中にて１０６５℃前後で４ｈ焼結後、６００℃前後１ｈの熱処理をした。
【００１６】
また、表１中の温度係数の比較は、１００〜２００℃の範囲の平均値であるが、１００℃以下においても、温度係数は、ほぼ同様の傾向を示している。
【００１７】
【表１】
表１の結果から、ＳｉとＣを同時に０．０５〜２．０原子％添加することにより、保磁力温度係数が著しく減少することが確認できる。
また、Ｎｏ．７（比較例４）は、ＳｉとＣを同時に添加するが、その添加量が２．０原子％以上の試料である。温度係数の改善は確認できるが、合わせて磁石の磁束密度が低下し、最大エネルギー積の低下が顕著であるため、実用上、好ましくない。
【００１９】
＜実験例２＞
液体急冷法により得られた種々の磁石粉末における保磁力の温度係数を、表２に示した。
それぞれの磁石粉末の元素組成は、（Ｎｄ５ Ｆｅ７１Ｃｏ５ Ｂ１９）１００−ｘ−ｙ Ｓｉｘ Ｃｙ において、ｘとｙを変化させたものである。
【００２０】
所定の割合に秤量された各金属を高周波溶解し、得られた合金を５ｍｍ前後に粉砕した合金チップを得た。得られた合金チップは、再び高周波溶解され、Ａｒガス雰囲気中で、周速度２５ｍ／ｓの回転ロールに吹き付けて薄帯を作製した。
【００２１】
また、表２中の温度係数の比較は、１００〜２００℃の範囲の平均値であるが、１００℃以下においても、温度係数は、ほぼ同様の傾向を示している。
【００２２】
【表２】
表２の結果から、急冷薄帯においても、ＳｉとＣを同時に０．０５〜２．０原子％添加することにより、保磁力温度係数が著しく減少することが確認できる。これらの薄帯は、必要に応じて熱処理してもよく、得られた粉末を樹脂で成形したボンド磁石としてモータに利用することができる。
【００２４】
また、Ｎｏ．７（比較例８）は、ＳｉとＣを同時に添加するが、その添加量が２．０原子％以上の試料である。温度係数の改善は確認できるが、合わせて磁石の磁束密度が低下し、最大エネルギー積の低下が顕著であるため、実用的とは言えない。
【００２５】
【発明の効果】
以上、詳細に説明したように、本発明によれば、その構成を、Ｎｄ，Ｄｙ，Ｆｅ，Ｃｏ及びＢを主成分とする磁石材料又はＮｄ，Ｆｅ，Ｃｏ及びＢを主成分とする磁石材料において、Ｓｉ及びＣを主相であるＮｄ ２ Ｆｅ １７ Ｂ相に一定量固溶させた永久磁石同期モータ用磁石としたため、以下のような効果が得られる。
【００２６】
本発明による磁石材料は、保磁力の温度上昇に伴う減少度合いが小さく、従来のＮｄ−Ｆｅ−Ｂ系磁石に比べて、使用限界温度が飛躍的に向上する。したがって、これらを電気自動車又はハイブリッド電気自動車の駆動用モータに使用することにより、高温環境下でのモータ動作が可能になり、また、モータ駆動の連続運転時間が向上する。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnet material used for a permanent magnet (PM) synchronous motor.
[0002]
[Prior art]
2. Description of the Related Art Permanent magnet (PM) synchronous motors have attracted attention as driving motors for electric vehicles or hybrid electric vehicles because of their high efficiency and high output density, and many vehicles using them have been developed.
[0003]
Since the output of the PM synchronous motor directly depends on the characteristics of the internal permanent magnet material, in practice, an Nd-Fe-B-based magnet having the largest energy product per unit volume is often used. In addition, due to the configuration of the motor, a current flows through the coil to generate a magnetic field, and a rotational force is obtained by using the magnetic field and the attraction of the permanent magnet. Therefore, heat is generated from the coil as the motor operates.
[0004]
However, the Nd—Fe—B-based magnet used as the above-described permanent magnet has a large reduction rate of coercive force due to a rise in temperature, and a serious problem is that magnet performance is impaired during operation (demagnetization). ing. In order to reduce the demagnetization, Dy, Co and the like are generally added for the purpose of increasing the coercive force itself of the magnet and maintaining a sufficient coercive force even at a high temperature.
[0005]
[Problems to be solved by the invention]
However, in such a conventional permanent magnet (PM) synchronous motor magnet, the rate of decrease in coercive force with temperature rise, that is, the temperature coefficient of coercive force is still as large as about -0.6% / ° C. However, there is a problem that the magnet performance is impaired during the operation. Essentially, it is necessary to improve the temperature coefficient (decrease the absolute value of the temperature coefficient) to improve the use limit temperature of the magnet.
Therefore, it has been an issue to improve the use limit temperature of the Nd-Fe-B-based magnet by improving the temperature coefficient of the coercive force of the Nd-Fe-B-based magnet (reducing the absolute value of the temperature coefficient). .
[0006]
The present invention has been made in view of such conventional problems, and has as its object to provide a permanent magnet (PM) synchronous motor magnet capable of operating a motor under a higher temperature environment.
[0007]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a magnet material containing Nd, Dy, Fe, Co and B as a main component or a magnet material containing Nd, Fe, Co and B as a main component. This problem is solved by using a permanent magnet (PM) synchronous motor magnet in which C and C are dissolved in a certain amount in the Nd 2 Fe 17 B phase as the main phase .
[0008]
Hereinafter, the operation of the present invention will be described.
In the magnet according to the present invention, since the temperature characteristics of the magnetocrystalline anisotropy are improved by the solid solution of Si and C in the Nd 2 Fe 17 B crystal as the main phase, the absolute value of the temperature coefficient of the coercive force is improved. The value decreases, and the degree of decrease in coercive force due to temperature rise can be suppressed to a low level.
As a result, the use limit temperature of the magnet is dramatically improved as compared with the related art, and the motor can be operated at a higher temperature.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the specific configuration of the permanent magnet (PM) synchronous motor magnet according to the present invention will be described in detail.
The Nd—Fe—B-based magnetic material used in the present invention is, as a main component, a known Nd 2 Fe 14 B-based compound, and its temperature characteristics of the coercive force are improved (reduction of the absolute value of the temperature coefficient of the coercive force). For this reason, Si and C are simultaneously added.
[0010]
These magnet materials are manufactured by a known powder metallurgy method, a liquid quenching method, and the like, and the limit operating temperature of the magnet is improved, so that a motor using this can be operated at a higher temperature than before. .
[0011]
All or part of Si and C in the magnet material according to the present invention dissolve in the Nd 2 Fe 17 B phase, which is the main phase, to change the crystal lattice distortion or the magnetic coupling state between elements. It is considered that this affects the temperature dependence of the magnetocrystalline anisotropy of the main phase. Thereby, the coercive force of the magnet can be kept from lowering due to temperature rise, so that the magnet can be used up to a higher temperature.
[0012]
In addition, as a result of examining the changes in the addition amounts of Si and C and the temperature coefficient of the coercive force, the effect (reduction of the absolute value of the temperature coefficient) of both elements becomes remarkable when added at 0.05 atomic% or more. start. When the addition amount is further increased, the temperature coefficient of the coercive force is improved (decreased in absolute value of the temperature coefficient) as compared with before the addition at 2.0 atomic% or more, but the magnetic flux density of the magnet decreases. Is remarkable. Therefore, the addition amount of Si and C is preferably 0.05 to 2.0 atomic%.
[0013]
Hereinafter, the present invention will be described in more detail by showing specific experimental examples of the present invention.
[0014]
<Experimental example 1>
Table 1 shows the temperature coefficient of coercive force of various sintered magnets manufactured by the powder metallurgy method.
Elemental composition of each of the magnets is obtained in (Nd 13 Dy 2 Fe 73 Co 5 B 7) 100-x-y Si x C y, by changing the x and y.
[0015]
Each metal weighed at a predetermined ratio was subjected to high frequency melting, and the alloy powder pulverized to a particle size of 3 to 5 μm was pressed at a pressing pressure of 2 kgf / cm 2 in a magnetic field of 25 kOe to form a green compact. These compacts were sintered in vacuum at about 1065 ° C. for 4 hours, and then heat-treated at about 600 ° C. for 1 hour.
[0016]
Further, the comparison of the temperature coefficients in Table 1 is an average value in the range of 100 to 200 ° C., but even at 100 ° C. or lower, the temperature coefficients show almost the same tendency.
[0017]
[Table 1]
From the results in Table 1, it can be confirmed that the coercivity temperature coefficient is significantly reduced by adding 0.05 to 2.0 atomic% of Si and C at the same time.
No. Sample No. 7 (Comparative Example 4) is a sample in which Si and C are added at the same time, but the added amount is 2.0 atomic% or more. Although the improvement of the temperature coefficient can be confirmed, the magnetic flux density of the magnet is also reduced, and the reduction of the maximum energy product is remarkable.
[0019]
<Experimental example 2>
Table 2 shows the temperature coefficient of the coercive force of various magnet powders obtained by the liquid quenching method.
Elemental composition of each of the magnetic powder, in (Nd 5 Fe 71 Co 5 B 19) 100-x-y Si x C y, it is obtained by changing the x and y.
[0020]
Each metal weighed at a predetermined ratio was subjected to high frequency melting, and an alloy chip obtained by grinding the obtained alloy to about 5 mm was obtained. The obtained alloy chip was melted by high frequency again and sprayed on a rotating roll having a peripheral speed of 25 m / s in an Ar gas atmosphere to produce a ribbon.
[0021]
Further, the comparison of the temperature coefficients in Table 2 is an average value in the range of 100 to 200 ° C., but even at 100 ° C. or less, the temperature coefficients show almost the same tendency.
[0022]
[Table 2]
From the results in Table 2, it can be confirmed that the coercive force temperature coefficient is significantly reduced by adding 0.05 to 2.0 atomic% of Si and C at the same time even in the quenched ribbon. These ribbons may be heat-treated as needed, and the obtained powder can be used for a motor as a bonded magnet formed of resin.
[0024]
No. Sample No. 7 (Comparative Example 8) is a sample in which Si and C are added at the same time, but the added amount is 2.0 atomic% or more. Although the improvement of the temperature coefficient can be confirmed, it is not practical because the magnetic flux density of the magnet is reduced and the maximum energy product is significantly reduced.
[0025]
【The invention's effect】
As described above in detail, according to the present invention, the configuration is such that a magnet material mainly containing Nd, Dy, Fe, Co and B or a magnet material mainly containing Nd, Fe, Co and B is used. In the above, a permanent magnet synchronous motor magnet in which a certain amount of Si and C are dissolved in the Nd 2 Fe 17 B phase, which is the main phase, is used, so that the following effects can be obtained.
[0026]
In the magnet material according to the present invention, the degree of decrease in coercive force with increasing temperature is small, and the use limit temperature is dramatically improved as compared with the conventional Nd-Fe-B-based magnet. Therefore, by using these for the drive motor of an electric vehicle or a hybrid electric vehicle, the motor can be operated in a high-temperature environment, and the continuous operation time of the motor drive is improved.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05826598A JP3588692B2 (en) | 1998-03-10 | 1998-03-10 | Permanent magnet synchronous motor magnet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05826598A JP3588692B2 (en) | 1998-03-10 | 1998-03-10 | Permanent magnet synchronous motor magnet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11260611A JPH11260611A (en) | 1999-09-24 |
| JP3588692B2 true JP3588692B2 (en) | 2004-11-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP05826598A Expired - Fee Related JP3588692B2 (en) | 1998-03-10 | 1998-03-10 | Permanent magnet synchronous motor magnet |
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| Country | Link |
|---|---|
| JP (1) | JP3588692B2 (en) |
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| Publication number | Publication date |
|---|---|
| JPH11260611A (en) | 1999-09-24 |
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