JP4214745B2 - Split iron core - Google Patents

Description

【００２５】
表1の結果から、Ｂ_Ｌ２1.60Ｔ以上かつＢ_Ｃ２／Ｂ_Ｌ２が0.80以下であり、さらにＷ_{Ｃ２００／５０}／Ｗ_{Ｌ２００／５０}が1.4以下の鋼板(C)および(D)から固定子を作製した場合に、特に高い効率が得られることが分かる。さらに、Ｗ_{Ｃ２００／５０}／Ｗ_{Ｌ２００／５０}が1.2以下の場合に、より高い効率が得られることもわかる。
以上の実験結果から、この発明の電磁鋼板は次の条件にて規制することした。
・磁化力200A/mにおける圧延方向および圧延方向と直角の方向の磁束密度をそれぞれＢ_Ｌ２およびＢ_Ｃ２とするとき、Ｂ_Ｌ２が1.60Ｔ以上
・ かつＢ_Ｃ２／Ｂ_Ｌ２が0.80以下
・ 最大磁化力200A/mおよび周波数50Hzにおける圧延方向および圧延方向と直角の方向の鉄損をそれぞれＷ_{Ｌ２００／５０}およびＷ_{Ｃ２００／５０}とするとき、Ｗ_{Ｃ２００／５０}／Ｗ_{Ｌ２００／５０}が1.4以下
【００２６】
以下、上記の各限定理由について説明する。
・Ｂ_Ｌ２:1.60Ｔ以上
従来は、回転機用材料の磁気特性のうち、特定方向の磁化のしやすさを測る量として、Ｂ₅₀すなわち磁化力5000A/mでの磁束密度が用いられていた。しかしながら、このＢ₅₀は材料の平均的な結晶方位のずれを大まかに見定めるのに適した指標であるものの、回転機で実際に生じる磁化力とは異なるものである。実際の回転機で材料を磁化させている磁化力は5000A/mに比べて低い。さらに、高透磁率材料を使用する場合は、通常の無方向性電磁鋼板を使用する場合よりもさらに低い磁化力にて、必要とする磁束密度を得ることができる。ゴス方位に近い結晶方位を有する電磁鋼板では、磁化力200A/m付近で通常必要とされる磁束密度を得ることができるため、磁化力200A/mでの磁束密度によって、各方向（Ｌ方向およびＣ方向）で生じる磁束密度を評価することとした。
【００２７】
そして、磁化力200A/mでの磁束密度が1.60Ｔに満たない場合は、分割鉄心により固定子の歯の方向を材料の透磁率の高い方向としたとしても、巻線に大きな電流を流す必要があり、効率が改善されないことから、Ｂ_Ｌ２を1.60Ｔ以上に限定した。より好ましくは、1.70Ｔ以上である。
【００２８】
・Ｂ_Ｃ２／Ｂ_Ｌ２：0.80以下
200A/m の磁化力が材料のＬ方向またはＣ方向に印加された場合に、Ｌ方向が優先的に磁化されてＣ方向の磁化を抑制することによって、固定子の歯先端部での回転機周方向における磁束成分の発生を抑えることが可能である。表１に示したように、Ｂ_Ｃ２／Ｂ_Ｌ２が0.80を越えると、このような作用を期待することができなくなり、鉄心鉄損の増加を招くことから、この範囲に限定する。より好ましくは、0.70以下である。
【００２９】
・Ｗ_{Ｃ２００／５０}／Ｗ_{Ｌ２００／５０}：1.4以下
Ｂ_Ｌ２が1.6Ｔ以上の透磁率の高い電磁鋼板を、分割鉄心により回転機に使用する場合は、上記のように磁化力200A/m程度での磁気特性を評価するのがよい。従来、電磁鋼板の鉄損の評価は、例えば最大磁束密度1.5Ｔのような、所定の磁束密度での鉄損により行われていた。ところが、回転機の固定子を局部的に見ると，必ずしも所定の磁束密度に達しているとは言えず、とくにＣ方向へ磁束が流れる場合、圧延方向と同じ磁束密度に達しているとは限らない。従って、この発明で着目した固定子の歯先端部における、磁束成分３の鉄損への寄与については、磁束密度を基準にした鉄損評価よりも磁化力を基準にした鉄損評価の方が適している。そこで、上記で述べた磁化力200A/mを最大値として磁化したときの鉄損を評価指標とし、Ｌ方向、Ｃ方向の鉄損の比による限定を行った。
【００３０】
ここで、測定の周波数は、歯先端での磁束成分３による鉄損の上昇が、主にヒステリシス損に起因し、若干渦電流損の寄与もあることから、50Hzでの測定値とするのが適当である。また、磁化力200A/mでの鉄損測定は、測定値の標準化のためには、磁束密度を正弦波に制御した条件で行うことが好ましい。
【００３１】
以上に従って定めた、鉄損の比Ｗ_{Ｃ２００／５０}／Ｗ_{Ｌ２００／５０}が1.4を越えると、上述した理由から固定子の歯先端部において鉄損増加が起こるため、比Ｗ_{Ｃ２００／５０}／Ｗ_{Ｌ２００／５０}を1.4以下に限定する。また、表１に示した結果から、鉄損の比Ｗ_{Ｃ２００／５０}／Ｗ_{Ｌ２００／５０}は1.2以下とすることがより望ましい。
【００３２】
以上の３つの要件が同時に実現されることによって、図１に示した磁束成分３による、鉄損増加を防止することが可能となる。というのは、Ｂ_Ｃ２／Ｂ_Ｌ２のみを規制する場合は、固定子の歯先端でのＣ方向の磁束成分を小さくすることができるものの、Ｃ方向の鉄損値の水準が高い場合には鉄損の増加を避けられないからであり、一方Ｗ_{Ｃ２００／５０}／Ｗ_{Ｌ２００／５０}のみを規制する場合は、鉄損の水準が小さくてもＣ方向の磁束量が大きいと，この部分の鉄損値の増加が避けられないからである。
【００３３】
さらに、Ｂ_Ｌ２:1.60Ｔ以上とするのは、透磁率の高い方向を分割鉄心の歯の方向とすることによって、励磁電流を低減し、低銅損・高トルクを実現するために必要であり、この条件の下に上記２つの要件が実現される必要がある。
【００３４】
なお、この発明に従う電磁鋼板を使用するに当たって、歯の方向（回転機の径方向）を磁束密度Ｂ_２が最も高い方向とする。すなわち、Ｂ_２が最も高い方向と歯の方向との間でずれが生じる場合は、このずれ角を15°以下とする必要がある。これは、ずれ角が大きいと歯方向の磁束密度が低下してトルクの低下を招くからである。ちなみに、ゴス方位に近い結晶方位を有する電磁鋼板では、Ｂ_２が最も高い方向は圧延方向となる。
【００３５】
この発明の要件を満たす電磁鋼板の一例として、上記の実験で鋼板（C）および(D)で示される電磁鋼板を示したが、その製造方法等は上記の方法に限定されるものではない。以下に、上記実験における鋼板（C）および(D)で所望の磁気特性が得られた理由について述べる。
すなわち、電磁鋼板（C）および(D)では、二次再結晶現象を利用した、ゴス方位近傍方位の二次再結晶粒の成長により、圧延方向の高い磁束密度（Ｂ_Ｌ２＝1.65Ｔ）、そしてＣ方向とＬ方向との磁束密度の比Ｂ_Ｃ２／Ｂ_Ｌ２≦0.80を同時に実現している。また、製品の表面に微細粒を残存させるとともに表面の平滑化を行い、さらに無張力のコーティングを塗布することにて、従来の方向性電磁鋼板と比べて表面張力を大幅に低減している。これらの効果により、Ｃ方向とＬ方向の鉄損の比Ｗ_{Ｃ２００／５０}／Ｗ_{Ｌ２００／５０}を1.4以下とすることが可能である。上記電磁鋼板内部の微細粒はＣ方向に磁化された場合の磁区構造細分化の核となり、表面の平滑化と無張力はＣ方向への磁化の進行を円滑に進行する作用を有する。従って、これらの効果によりＣ方向の鉄損が低下する。
【００３６】
なお、上記の電磁鋼板は、以下に示す適正条件の下に、製造することが有利である。
まず、出発材について、Siは電気抵抗率増加により渦電流損を低減するとともに、鉄のBCC組織を安定させて高温での焼鈍を可能にするのに有用な元素である。Siが２mass％を下回ると、このような効果が得られず、一方８mass％を越えると加工性が劣化するため、２〜８mass％とするのがよい。
【００３７】
次に、Ｃ量がスラブ段階で0.08mass％を越えると、脱炭焼鈍後に十分に除去することが不可能になることから、0.08mass％以下とするのがよい。
【００３８】
Mnは、熱間加工性改善に有用な元素である。0.005mass％に満たないと効果が乏しく、3.0mass％を越えると磁束密度低下を招くため、0.005〜3.0mass％とするのがよい。
【００３９】
スラブ中のAlが100ppmを越えたり、Ｎが50ppmを越えたりすると、二次再結晶の際に良好な方位の成長を妨げるため、Alは100ppm以下およびＮは50ppm以下とするのがよい。
さらに、粒成長を阻害するS、Se、Ti、Nb、B、TaおよびＶについても、それぞれ50ppm以下とするのがよい。
【００４０】
次いで、製造方法について述べる。
上記の成分組成になるスラブは熱間圧延に供されるが、その際の熱延板焼鈍は、結晶進行のために800℃以上とするのが有利であり、良好方位のゴス方位近傍粒を得るには、1050℃以上とするのが望ましい。
【００４１】
さらに、冷間圧延の後、800℃以上、望ましくは1050℃以上で中間焼鈍を施すことが望ましい。ここで、熱延板焼鈍と中間焼鈍のいずれかを1050℃以上とすることによって、ゴス方に近い結晶粒が得られやすくなるとともに、表層付近の適正量の微細粒が発生しやすくなる。最終の冷間圧延にあっては、圧延温度を100〜260℃とし、冷間圧延途中で100〜250℃の範囲の時効処理を行うことが、良好なゴス組織を発達させる点で有利である。
【００４２】
最終冷延後の再結晶焼鈍では、最終焼鈍後の粒径を30〜80μmの範囲とする。これは、粒径30μm以下の場合、二次再結晶粒の方位集積度が低下し、一方80μmを越えると二次再結晶が起こらず、圧延方向の磁束密度が低下するからである。
【００４３】
その後、焼鈍分離剤を塗布することなく、50〜130Mpaおよび水素量60〜100vol％の雰囲気にて最終仕上げ焼鈍を行う。ここでの条件がこの発明の範囲の電磁鋼板を得るための最も重要な条件である。
すなわち、焼鈍分離剤を塗布しないとともに、巻き取り張力を適正に調節することでコイルの層間に適正な空間を設け、さらに最終仕上げ焼鈍時の水素量を60〜100 vol％とすることにより、最終仕上げ焼鈍中のコイルの層間に水素を到達しやすくして、この水素の効果で表面の微細粒の生成を促進する。すなわち、水素が最終仕上げ焼鈍の一次粒成長過程で鋼板表面に十分な濃度で存在する場合、窒素等が鋼中に進入してインヒビター（析出物）を形成するのを防止し、あるいは一旦形成されたインヒビターを分解することにより、表層部分の結晶粒の成長を促進するからである。
【００４４】
ここで、上記の焼鈍分離剤を塗布しないことおよび、巻き取り張力を130MPa以下とすることは、コイルの層間に適正な空隙を確保するために必要である。一方、巻き取り張力が50MPaを下回ると、最終仕上げ焼鈍中のコイル強度が低下して形状の劣化を招く。巻き取り張力を50〜130MPaの範囲とするのは、コイルの全長の90％以上とするのが望ましい。これは、最終仕上げ焼鈍後のコイル形状改善のために、コイルの一部で130MPa以上の張力とすることも可能であるが、このような部分が10％以上となると、この発明の範囲外となる部分が増加して歩留りの低下を招くからである。
【００４５】
また、最終仕上げ焼鈍中の水素量が60vol％を下回ると、最終仕上げ焼鈍中に表層の結晶粒の成長が阻害されて微細粒が残存しにくくなるため、60vol％以上とするのがよい。
ここで、最終仕上げ焼鈍の一次再結晶粒成長過程においては、表層粒の粗大化を促進した方が、二次再結晶粒の発生後に二次再結晶粒に蚕食されずに、適正量の微細粒を残存させることが可能になり有利である。なお、水素量を60vol％以上とするのは、表層粒の成長が起こり始める700℃以上とするのがよい。700℃未満の雰囲気については、特に限定されない。
【００４６】
また、最終仕上げ焼鈍の到達温度としては、二次再結晶を生成させるためには800℃以上とする必要があり、微細粒の消失を防ぐためには900℃以下とする必要がある。そして、800℃〜900℃の滞留時間は、二次再結晶を完了させるとともに、適正な微細粒を残存させる観点から、10〜100時間の範囲とするのがよい。
【００４７】
さらに、絶縁性確保の観点から塗布される絶縁コーティングは、打抜き性確保の観点から、有機系のコーティングが望ましいが、溶接性を重視する場合には、無機系のコーティングを適用するのがよい。
【００４８】
上記の製造方法による電磁鋼板では、二次再結晶現象を利用することでゴス方位近傍方位の二次再結晶粒の成長により、高いＬ方向磁束密度およびＬ方向を磁化容易方向とする強い磁気異方性と、低いＣ方向鉄損とを同時に実現することが可能である。また、最終仕上げ焼鈍前の結晶粒径と、最終仕上げ焼鈍の温度および時間との条件により、製品板に適当量の微細粒を残存させるとともに、焼鈍分離剤を塗布することなく長時間の最終仕上げ焼鈍を行うことにより、表面を平滑化し、さらに無張力のコーティングを塗布することにより、従来の方向性電磁鋼板と比べて表面張力を大幅に低減している。これらの効果により、Ｃ方向とＬ方向における鉄損の比Ｗ_{Ｃ２００／５０}／Ｗ_{Ｌ２００／５０}を1.4以下（望ましくは1.2以下）とすることが可能である。上記電磁鋼板内部の微細粒は、Ｃ方向に磁化された場合の磁区構造の細分化の核となり、表面の平滑化と無張力はＣ方向への磁化の進行を円滑に進行する作用を有すると推定される。従って、これらの効果により圧延直角方向の鉄損が低下すると考えられる。
【００４９】
【実施例】
実施例1
Ｃ：0.005mass％、Si：3.0mass％、Mn：0.08mass％およびSb：0.03mass％を含み、かつAl：30ppmおよびＮ：25ppmに低減した、鋼スラブを連続鋳造にて製造し、次いで1100℃で20分加熱後、熱間圧延により2.5mm厚の熱延板とした。この熱延板に、1000℃、60秒間の熱延板焼鈍を施した後、常温で冷間圧延を行って0.35mmの最終板厚としたのち、水素80vol％、窒素20vol％および露点35℃の雰囲気にて、925℃で30秒の再結晶焼鈍を行い、焼鈍分離剤を塗布せずに、コイル（a）は150MPa、コイル（b）および（c）は100MPa、そしてコイル（d）は60MPaの張力にて巻き取った。
【００５０】
次いで、露点-30℃で、コイル(b)はAr50vol％および水素50vol％の混合雰囲気中、またコイル(a)、(c)、(d)はAr30vol％および水素70vol％の混合雰囲気中、にて、それぞれ常温から850℃までを50℃/hで昇温し、850℃で20時間保持する最終仕上げ焼鈍を行った。最終仕上げ焼鈍終了後、重クロム酸アルミニウム、エマルジョン樹脂およびエチレングリコールを混合したコーティング液を塗布し、300℃で焼き付けて製品とした。
また、比較材として同じ厚さの無方向性電磁鋼板を鋼板(ｅ)として用意した。
【００５１】
これらの製品板(a)〜(e)から圧延方向および圧延直角方向のエプスタイン試験片を採取し、各方向の磁気特性を測定した。その結果を表２に示す。
また、これらの材料から、図２に示す3相4極の磁極集中巻のブラシレスＤＣモータの固定子２を作製した。回転子１は表面磁石型とした。これらの電動機を回転数1500rpm、トルク3Nmで定常回転試験を行い、効率を求めた。表２に効率の測定結果を併記した。
【００５２】
【表２】

【００５３】
表２に示すように、この発明の電磁鋼板から上記の電動機に固定子２を製造した場合、従来の一方向性電磁鋼板から作製したモータに比べて高い効率が得られている。
【００５４】
実施例２
上記実施例1と同じ素材から、図3に示す3相4極の埋込磁石型シンクロナスモータを作製した。これらの電動機を回転数2500rpm、トルク2Nmで定常回転試験を行い、効率を求めた。その結果を、表3に併記する。
【００５５】
【表３】

【００５６】
表3に示すように、この発明の電磁鋼板から上記の電動機に固定子を製造した場合、従来の一方向性電磁鋼板から作製したモータに比べて高い効率が得られている。
【００５７】
【発明の効果】
この発明の分割型鉄心によれば、永久磁石を回転子に用いた回転機の固定子において、鉄損低減が可能であり、従来にも増して高効率の回転機の提供が可能となる。従って、この分割型鉄心を回転機へ適用すれば、エネルギー損失の低減に大きく寄与することになる。
【図面の簡単な説明】
【図１】 永久磁石を固定子に用いた回転機の固定子内部での磁束の流れを模式的に示した図である。
【図２】 表面磁石型のブラシレスＤＣモータ（分割鉄心型）の模式図である。
【図３】 磁石埋込型のシンクロナスモータ（分割鉄心型）の模式図である。
【符号の説明】
１ 回転子
２ 固定子
３ 磁束の流れ
４ 磁束の流れ[0001]
BACKGROUND OF THE INVENTION
The present invention, split core, particularly adapted as a rotary machine stator, such as an electric motor or a generator using a permanent magnet in the rotor, to split cores of high efficiency.
[0002]
[Prior art]
Due to social demands for energy saving, there is a strong demand for higher efficiency of rotating machines, and various types of rotating machines and iron core materials used therefor have been proposed.
For example, the progress of permanent magnets in recent years is remarkable, and synchronous motors using permanent magnets for the rotor can obtain high efficiency, and the frequency of use thereof is increasing.
[0003]
On the other hand, a split core structure in which the stator core is split is easy to wind and can realize a high winding filling rate, and thus advantageously acts to increase the efficiency of the rotating machine. Furthermore, in the case of a split core structure, it is possible to make a structure that takes into account the magnetic anisotropy of the core material, and it is also possible to construct the core from a plurality of different materials, which increases the efficiency of the rotating machine. It can be said that it is an advantageous structure for further pushing forward.
[0004]
By the way, the energy efficiency of a rotating machine is quantified by the ratio of output to input, but the loss that is the difference between input and output includes iron loss that occurs in the iron core of the rotating machine and copper loss that occurs in the winding. There are mechanical losses caused by bearings, and stray loss including various other factors. Among these, iron loss occupies a relatively large ratio, and lowering iron loss of the core material is particularly important for improving the efficiency of the rotating machine.
[0005]
In particular, in a rotating machine using a permanent magnet as a rotor, as will be described in detail later, a magnetic flux component is generated in a stator portion facing the rotor using a permanent magnet, which causes an increase in iron loss. .
[0006]
Here, regarding the electromagnetic steel sheet suitable for the material for the split core, for example, Patent Document 1 includes a rolling direction (hereinafter referred to as L direction) and a direction perpendicular to the rolling direction (hereinafter referred to as C direction). A technique for improving the efficiency of an electric motor by considering the balance of magnetic characteristics is disclosed. The main content of this technique is to improve the magnetic characteristics in the C direction by preventing excessive accumulation in the Goss direction.
[0007]
However, this technology only provides an electrical steel sheet with a large deviation in the secondary recrystallized grain orientation from the Goss orientation, and has improved the punchability by limiting the oxide layer on the surface. There is no big difference with steel plate. Furthermore, there is no mention about eliminating the above-described increase in iron loss, which is peculiar to a rotating machine using a permanent magnet as a rotor, which has been attracting attention in recent years.
[0008]
Further, in Patent Document 2, the magnetic properties of the C-direction is relatively good, the iron core material for rotating machine has been proposed, for L direction iron loss W _15/50 in the C direction of the iron loss W _15/50 A material with a low ratio is obtained. However, this technique also merely focuses on the balance of iron loss in the L direction and the C direction, and a solution to the above-mentioned problem peculiar to a rotating machine using a permanent magnet as a rotor is presented. Absent.
[0009]
[Patent Document 1]
JP 2000-87139 A [Patent Document 2]
Japanese Patent Laid-Open No. 7-18334
[Problems to be solved by the invention]
As described above, although efforts to improve the efficiency of rotating machines have been promoted from both the device structure and iron core materials, iron core reduction in iron cores has not always been sufficient. The reason for this is that the material design that takes into account the increase in iron loss in the local region of the rotating machine has not been performed.
[0011]
Accordingly, the present invention is by advantageously avoiding an increase in iron loss generated in the stator side of the motor using a permanent magnet in the rotor to achieve a high efficiency of the rotating machine, with a split type iron core The purpose is to propose.
[0012]
[Means for Solving the Problems]
The inventors have intensively studied to reduce the iron loss increase factor generated at the tooth tip of the stator in a rotating machine mainly using a permanent magnet as a rotor. It came to guide.
[0013]
That is, the present invention is a split type iron core that constitutes a stator of a rotating machine that uses a permanent magnet as a rotor, and the electromagnetic steel sheets constituting the iron core are Si: 2.0 to 8.0 mass% and Mn : 0.005 to 3.0. containing mass%, when the magnetic flux density in the rolling direction and the rolling direction and the direction perpendicular to the magnetizing force 200A / m, respectively _{B L2} and _{B C2, B L2} is more than 1.60T and _B C2 _{/ B L2} is 0.80 or less Further, when the iron loss in the rolling direction at a maximum magnetizing force of 200 A / m and a frequency of 50 Hz and in the direction perpendicular to the rolling direction is W _{L200 / 50} and W _{C200 / 50} , respectively, W _{C200 / 50} / W _{L200 / 50} There Ri der than 1.4, a split iron core flux density of the electromagnetic steel plates is highest direction, characterized in Rukoto such as the direction of the teeth of the split core.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
This invention is particularly in the rotating machine using permanent magnets to the rotor, and to provide a split type iron heart constituting a stator. Therefore, it is such a rotating machine, as an example a brushless DC motor of the surface magnet type, detailed information on the inventions.
[0015]
That is, FIG. 1 schematically shows the flow of magnetic flux inside the stator core in a surface magnet type brushless DC motor. In this figure, reference numeral 1 is a rotor using a permanent magnet, and 2 is a stator. The flow of magnetic flux in the teeth 2 a of the stator 2 is indicated by arrows 3 or 4.
[0016]
Now, as shown in FIG. 1, in the rotating machine using a permanent magnet for the rotor 1, the point where the polarity of the magnetic pole in the rotor 1 changes in the teeth 2a of the stator 1 is opposite to the teeth 2a. In the tooth 2a, a magnetic flux component 3 forming a magnetic circuit closed from the N pole toward the S pole is generated. Although such a magnetic flux component 3 does not contribute to torque, it causes an increase in iron loss due to an excessive increase in magnetic flux density.
[0017]
Here, the generation of the magnetic flux component 3 is particularly noticeable in a motor using a permanent magnet for the rotor 1, and among these, the magnetic force on the surface of the rotor 1 is strong and the range is narrower than the tip width of the teeth 2a. It is particularly easy to increase in a rotating machine having a structure with different magnetic poles.
[0018]
The inventors have come to the conclusion that the following measures are effective as means for suppressing an increase in iron loss due to the magnetic flux component as described above.
(I) A material having strong magnetic anisotropy is used as the tooth material, and the easy magnetization direction is the tooth direction (radial direction). Thereby, generation | occurrence | production of the magnetic flux component of the circumferential direction is suppressed by the tooth tip, and the local increase of the iron loss in a tooth tip part is suppressed.
(Ii) Reduce iron loss in the direction of hard magnetization compared to the direction of easy magnetization. This makes it possible to avoid an increase in iron loss even when a circumferential magnetic flux component is generated at the tip of the tooth.
[0019]
Here, in order to realize the above (i), for example, there is a method of using the rolling direction of a normal unidirectional electrical steel sheet as the tooth direction. Various types of rotating machines having such a structure have been proposed in the past, but the iron loss of the iron core tended to be larger than the value predicted from the magnetic properties of the electrical steel sheet predicted by the Epstein test. As this cause, the influence of the magnetic flux component which forms a closed circuit in the above-mentioned tooth | tip tip part can be considered. The unidirectional electrical steel sheet has strong magnetic anisotropy and small permeability in the C direction, so that the generation of the magnetic flux component 3 in the circumferential direction at the tooth tip is suppressed to some extent, but the iron loss in the C direction is L Since it is larger than the direction, the iron loss increases rapidly as the magnetic flux component in the C direction increases. Therefore, it is important to use a material that satisfies the above condition (ii) in addition to the above condition (i). By satisfying these two conditions, it is possible to positively prevent the above-described increase in iron loss and reduce the loss of the entire rotating machine.
[0020]
That is, the inventions has not been conventionally considered, is intended to prevent an increase of iron loss due to magnetic flux component forming a closed circuit with the teeth tips of the stator, in particular the fixed rotary machine having a permanent magnet rotor When used as a child, the superiority becomes more remarkable.
[0021]
Next, in order to more specifically define the above conditions (i) and (ii), the following examination was performed.
That is, continuous casting of a steel slab containing C: 0.005 mass%, Si: 3.0 mass%, Mn: 0.08 mass%, Sb: 0.03 mass%, with Al reduced to 30 ppm and N reduced to 25 ppm. Manufactured by. Next, after heating the steel slab at 1100 ° C for 20 minutes, hot rolled into a 2.5 mm thick hot rolled sheet, after performing hot rolled sheet annealing at 1000 ° C for 60 seconds, cold rolling at room temperature Finished to a final thickness of 0.35 mm. Then, after recrystallization annealing at 925 ° C and 30 seconds in an atmosphere of hydrogen: 80vol% and nitrogen: 20vol%, coil (A) is 150MPa, coil (B ) And (C) were wound at a tension of 100 MPa, and coil (D) was wound at a tension of 60 MPa.
[0022]
Next, at a dew point of −30 ° C., the coil (B) is in a mixed atmosphere of Ar 50 vol% and hydrogen 50 vol%, and the coils (A), (C), and (D) are in a mixed atmosphere of Ar 30 vol% and hydrogen 70 vol%. The final finish annealing was performed by raising the temperature from room temperature to 850 ° C. at 50 ° C./h and holding at 850 ° C. for 20 hours. At this time, the coil (A) and (B) should be at an atmosphere of H ₂ : 50 vol% and N ₂ : 50 vol%, and the coil (C) should be H ₂ : 80 vol% and N ₂ : 20 vol%. And annealed. Then, the coating liquid which mixed aluminum dichromate, emulsion resin, and ethylene glycol was apply | coated, and it baked at 300 degreeC, and manufactured the electrical steel sheet. In addition to the electrical steel sheets (A) to (D) described above, (E): a non-oriented electrical steel sheet was separately prepared for comparison.
[0023]
2 are punched out into the iron core dividing elements indicated by dotted lines in FIG. 2, integrated by caulking, and then wound (magnetic pole concentrated winding: not shown) to form the stator 2, FIG. As shown in Fig. 2, a surface magnet type rotor 1 is attached to form an electric motor. The efficiency of this electric motor was measured under the conditions of a rotational speed of 1500 rpm and a torque of 3 Nm. Table 1 shows the magnetic properties and motor efficiency of each material.
[0024]
[Table 1]

[0025]
From the results of Table 1, a stator is produced from steel plates (C) and (D) having B _{L2 of} 1.60 T or more, B _C2 / B _L2 of 0.80 or less, and W _{C200 / 50} / W _{L200 / 50} of 1.4 or less. It can be seen that particularly high efficiency can be obtained. It can also be seen that higher efficiency is obtained when W _{C200 / 50} / W _{L200 / 50} is 1.2 or less.
From the above experimental results, the electrical steel sheet of the present invention was regulated under the following conditions.
・ When the magnetic flux density in the rolling direction at a magnetizing force of 200 A / m and the direction perpendicular to the rolling direction is B _L2 and B _C2 , B _L2 is 1.60 T or more, and B _C2 / B _L2 is 0.80 or less. When the iron loss in the rolling direction at a frequency of 200 A / m and a frequency of 50 Hz and in the direction perpendicular to the rolling direction is W _{L200 / 50} and W _{C200 / 50} , respectively, W _{C200 / 50} / W _{L200 / 50} is 1.4 or less.
Hereinafter, each limitation reason will be described.
-B _L2 : 1.60T or higher Conventionally, among magnetic properties of rotating machine materials, B _50, that is, the magnetic flux density at a magnetizing force of 5000 A / m, was used as an amount to measure the ease of magnetization in a specific direction. . However, this B ₅₀ is an index suitable for roughly determining the deviation of the average crystal orientation of the material, but is different from the magnetizing force actually generated in the rotating machine. The magnetizing force that magnetizes the material with an actual rotating machine is lower than 5000 A / m. Furthermore, when a high magnetic permeability material is used, the required magnetic flux density can be obtained with a lower magnetizing force than when a normal non-oriented electrical steel sheet is used. In an electrical steel sheet having a crystal orientation close to the Goss orientation, a magnetic flux density that is normally required near a magnetizing force of 200 A / m can be obtained. Therefore, depending on the magnetic flux density at a magnetizing force of 200 A / m, each direction (L direction and The magnetic flux density generated in the (C direction) was evaluated.
[0027]
If the magnetic flux density at a magnetizing force of 200 A / m is less than 1.60 T, a large current must flow through the winding even if the direction of the stator teeth is set to a direction in which the magnetic permeability of the material is high due to the split iron core. Since the efficiency is not improved, B _L2 is limited to 1.60 T or more. More preferably, it is 1.70 T or more.
[0028]
・ B _C2 / B _L2 : 0.80 or less
When a magnetizing force of 200 A / m 2 is applied in the L direction or the C direction of the material, the L direction is preferentially magnetized to suppress the magnetization in the C direction, thereby rotating the rotating machine at the tooth tip of the stator. It is possible to suppress the generation of magnetic flux components in the circumferential direction. As shown in Table 1, when B _C2 / B _L2 exceeds 0.80, such an effect cannot be expected and the iron core loss is increased, so the range is limited to this range. More preferably, it is 0.70 or less.
[0029]
・ W _{C200 / 50} / W _{L200 / 50} : 1.4 or less B When _L2 is 1.6T or more and high magnetic permeability steel sheet is used for a rotating machine with a split iron core, the magnetizing force is about 200A / m as described above. It is better to evaluate the magnetic properties of Conventionally, the evaluation of the iron loss of an electromagnetic steel sheet has been performed by the iron loss at a predetermined magnetic flux density such as a maximum magnetic flux density of 1.5T. However, when the stator of the rotating machine is viewed locally, it cannot always be said that the predetermined magnetic flux density has been reached. In particular, when the magnetic flux flows in the C direction, it does not always reach the same magnetic flux density as in the rolling direction. Absent. Therefore, regarding the contribution of the magnetic flux component 3 to the iron loss at the tooth tip of the stator focused on in the present invention, the iron loss evaluation based on the magnetizing force is more effective than the iron loss evaluation based on the magnetic flux density. Is suitable. Therefore, the iron loss when magnetized with the magnetizing force of 200 A / m described above as the maximum value is used as an evaluation index, and limitation is made by the ratio of the iron loss in the L direction and the C direction.
[0030]
Here, the measurement frequency is measured at 50 Hz because the increase in the iron loss due to the magnetic flux component 3 at the tooth tip is mainly due to the hysteresis loss and also contributes a little to the eddy current loss. Is appropriate. Further, the iron loss measurement at a magnetizing force of 200 A / m is preferably performed under the condition that the magnetic flux density is controlled to a sine wave in order to standardize the measurement value.
[0031]
If the iron loss ratio W _{C200 / 50} / W _{L200 / 50} determined in accordance with the above exceeds 1.4, the iron loss increases at the tooth tip of the stator for the reason described above, and the ratio W _{C200 / 50} / W _{L200 / 50} is limited to 1.4 or less. From the results shown in Table 1, the iron loss ratio W _{C200 / 50} / _{WL200 / 50} is more preferably 1.2 or less.
[0032]
By realizing the above three requirements at the same time, it is possible to prevent an increase in iron loss due to the magnetic flux component 3 shown in FIG. This is because when only B _C2 / B _L2 is regulated, the magnetic flux component in the C direction at the tooth tip of the stator can be reduced, but when the iron loss value in the C direction is high, iron is used. This is because an increase in loss is unavoidable. On the other hand, when only W _{C200 / 50} / W _{L200 / 50} is regulated, if the amount of magnetic flux in the C direction is large even if the level of iron loss is small, the iron loss of this portion is reduced. This is because an increase in value is inevitable.
[0033]
Furthermore, B _L2 : 1.60 T or more is necessary for reducing the excitation current and realizing low copper loss and high torque by setting the direction of high permeability to the direction of the teeth of the split core. Under these conditions, the above two requirements need to be realized.
[0034]
Incidentally, when using the electromagnetic steel sheet according to the present invention, the direction of the teeth (the radial direction of the rotating machine) is the magnetic flux density B ₂ to the highest direction. That is, when the B ₂ is deviation occurs between the direction of the highest direction and teeth, the deviation angle is required to be 15 ° or less. This is because if the deviation angle is large, the magnetic flux density in the tooth direction is lowered and the torque is lowered. Incidentally, in the electromagnetic steel sheet having a crystal orientation close to the Goss orientation, B ₂ is the highest direction is the rolling direction.
[0035]
As an example of the electrical steel sheet that satisfies the requirements of the present invention, the electrical steel sheet indicated by steel sheets (C) and (D) was shown in the above experiment, but the manufacturing method and the like are not limited to the above method. The reason why the desired magnetic properties were obtained with the steel plates (C) and (D) in the above experiment will be described below.
That is, in the magnetic steel sheets (C) and (D), a high magnetic flux density in the rolling direction (B _L2 = 1.65 T) is obtained by the growth of secondary recrystallized grains in the vicinity of the Goth direction using the secondary recrystallization phenomenon. And the ratio B _C2 / B _L2 ≦ 0.80 of the magnetic flux density between the C direction and the L direction is realized at the same time. Moreover, the surface tension is greatly reduced compared with the conventional grain-oriented electrical steel sheet by leaving fine particles on the surface of the product, smoothing the surface, and applying a tension-free coating. With these effects, the ratio of iron loss in the C direction to the L direction W _{C200 / 50} / W _{L200 / 50} can be made 1.4 or less. The fine grains inside the magnetic steel sheet serve as the core of the magnetic domain structure fragmentation when magnetized in the C direction, and the smoothing of the surface and no tension have the effect of smoothly proceeding the magnetization in the C direction. Therefore, the iron loss in the C direction is reduced by these effects.
[0036]
In addition, it is advantageous to manufacture said electromagnetic steel plate on the appropriate conditions shown below.
First of all, as a starting material, Si is an element useful for reducing the eddy current loss by increasing the electrical resistivity and stabilizing the iron BCC structure and enabling annealing at a high temperature. If Si is less than 2 mass%, such an effect cannot be obtained. On the other hand, if it exceeds 8 mass%, the workability deteriorates, so 2-8 mass% is preferable.
[0037]
Next, if the amount of C exceeds 0.08 mass% at the slab stage, it becomes impossible to remove it sufficiently after decarburization annealing, so it is preferable to make it 0.08 mass% or less.
[0038]
Mn is an element useful for improving hot workability. If it is less than 0.005 mass%, the effect is poor, and if it exceeds 3.0 mass%, the magnetic flux density is lowered, so 0.005 to 3.0 mass% is preferable.
[0039]
If Al in the slab exceeds 100 ppm or N exceeds 50 ppm, the growth of good orientation is hindered during secondary recrystallization. Therefore, Al is preferably 100 ppm or less and N is 50 ppm or less.
Further, S, Se, Ti, Nb, B, Ta and V, which inhibit grain growth, are each preferably 50 ppm or less.
[0040]
Next, a manufacturing method will be described.
The slab having the above component composition is subjected to hot rolling, and the hot-rolled sheet annealing at that time is advantageously 800 ° C. or more for the progress of the crystal, and the grains in the vicinity of the Goss direction with good orientation are used. In order to obtain it, it is desirable to set it as 1050 degreeC or more.
[0041]
Furthermore, it is desirable to perform intermediate annealing at 800 ° C. or higher, preferably 1050 ° C. or higher after cold rolling. Here, by setting any one of hot-rolled sheet annealing and intermediate annealing to 1050 ° C. or higher, crystal grains close to the Goth direction can be easily obtained, and an appropriate amount of fine grains near the surface layer is easily generated. In the final cold rolling, it is advantageous in terms of developing a good goth structure that the rolling temperature is set to 100 to 260 ° C. and the aging treatment in the range of 100 to 250 ° C. is performed during the cold rolling. .
[0042]
In the recrystallization annealing after the final cold rolling, the grain size after the final annealing is set in the range of 30 to 80 μm. This is because, when the grain size is 30 μm or less, the degree of orientation accumulation of secondary recrystallized grains decreases, while when it exceeds 80 μm, secondary recrystallization does not occur and the magnetic flux density in the rolling direction decreases.
[0043]
Then, final finish annealing is performed in an atmosphere of 50 to 130 MPa and a hydrogen amount of 60 to 100 vol% without applying an annealing separator. This condition is the most important condition for obtaining the electromagnetic steel sheet within the scope of the present invention.
In other words, without applying an annealing separator, by properly adjusting the winding tension, an appropriate space is provided between the layers of the coil, and the amount of hydrogen at the final finish annealing is 60-100 vol%. Hydrogen is easily reached between the layers of the coil during the finish annealing, and the effect of this hydrogen promotes the formation of fine particles on the surface. That is, when hydrogen is present at a sufficient concentration on the steel sheet surface during the primary grain growth process in the final finish annealing, nitrogen or the like is prevented from entering the steel to form an inhibitor (precipitate) or once formed. This is because the growth of crystal grains in the surface layer portion is promoted by decomposing the inhibitor.
[0044]
Here, not applying the above-mentioned annealing separating agent and setting the winding tension to 130 MPa or less are necessary to secure an appropriate gap between the coil layers. On the other hand, when the winding tension is less than 50 MPa, the coil strength during the final finish annealing is lowered, and the shape is deteriorated. The winding tension in the range of 50 to 130 MPa is desirably 90% or more of the entire length of the coil. In order to improve the coil shape after final finish annealing, it is possible to set a tension of 130 MPa or more in a part of the coil, but if such a part becomes 10% or more, it is out of the scope of the present invention. This is because the portion to be increased causes a decrease in yield.
[0045]
Further, if the amount of hydrogen in the final finish annealing is less than 60 vol%, the growth of crystal grains on the surface layer is hindered during the final finish annealing and it becomes difficult for the fine grains to remain.
Here, in the primary recrystallized grain growth process in the final finish annealing, the promotion of the coarsening of the surface layer grains is not phagocytosed by the secondary recrystallized grains after the generation of secondary recrystallized grains, and an appropriate amount of fine grains It is advantageous that it is possible to leave grains. Note that the hydrogen amount is preferably set to 60 vol% or more at 700 ° C or more at which surface grain growth starts to occur. The atmosphere below 700 ° C. is not particularly limited.
[0046]
In addition, the ultimate temperature of final finish annealing needs to be 800 ° C. or higher in order to generate secondary recrystallization, and needs to be 900 ° C. or lower in order to prevent disappearance of fine grains. The residence time of 800 ° C. to 900 ° C. is preferably in the range of 10 to 100 hours from the viewpoint of completing secondary recrystallization and leaving appropriate fine grains.
[0047]
Furthermore, the insulating coating applied from the viewpoint of ensuring insulation is preferably an organic coating from the viewpoint of ensuring punchability, but an inorganic coating is preferably applied when emphasizing weldability.
[0048]
In the electrical steel sheet produced by the above manufacturing method, by utilizing the secondary recrystallization phenomenon, the growth of secondary recrystallized grains in the direction near the Goss azimuth causes a strong magnetic anomaly with a high L direction magnetic flux density and an L direction as an easy magnetization direction. It is possible to simultaneously realize the directivity and the low C-direction iron loss. Also, depending on the conditions of the crystal grain size before final finishing annealing and the temperature and time of final finishing annealing, an appropriate amount of fine grains remain on the product plate and the final finishing for a long time without applying an annealing separator. By performing the annealing, the surface is smoothed, and further, by applying a tension-free coating, the surface tension is greatly reduced as compared with the conventional grain-oriented electrical steel sheet. With these effects, the ratio of iron loss in the C direction and the L direction W _{C200 / 50} / W _{L200 / 50} can be made 1.4 or less (preferably 1.2 or less). The fine grains inside the magnetic steel sheet serve as the core of the subdivision of the magnetic domain structure when magnetized in the C direction, and the smoothing of the surface and no tension have the effect of smoothly proceeding the magnetization in the C direction. Presumed. Therefore, it is considered that the iron loss in the direction perpendicular to the rolling is reduced by these effects.
[0049]
【Example】
Example 1
A steel slab containing C: 0.005 mass%, Si: 3.0 mass%, Mn: 0.08 mass% and Sb: 0.03 mass% and reduced to Al: 30 ppm and N: 25 ppm was manufactured by continuous casting, and then 1100 After heating at 20 ° C. for 20 minutes, a hot-rolled sheet having a thickness of 2.5 mm was formed by hot rolling. This hot-rolled sheet was subjected to hot-rolled sheet annealing at 1000 ° C for 60 seconds, followed by cold rolling at room temperature to obtain a final sheet thickness of 0.35 mm, then 80 vol% hydrogen, 20 vol% nitrogen, and 35 ° C dew point Recrystallization annealing at 925 ° C for 30 seconds in the atmosphere, coil (a) is 150 MPa, coils (b) and (c) are 100 MPa, and coil (d) is It was wound up with a tension of 60 MPa.
[0050]
Next, at a dew point of −30 ° C., the coil (b) is in a mixed atmosphere of Ar 50 vol% and hydrogen 50 vol%, and the coils (a), (c) and (d) are in a mixed atmosphere of Ar 30 vol% and hydrogen 70 vol%. The final finish annealing was performed by raising the temperature from room temperature to 850 ° C. at 50 ° C./h and holding at 850 ° C. for 20 hours. After the final finish annealing, a coating liquid in which aluminum dichromate, emulsion resin and ethylene glycol were mixed was applied and baked at 300 ° C. to obtain a product.
Moreover, a non-oriented electrical steel sheet having the same thickness was prepared as a steel sheet (e) as a comparative material.
[0051]
From these product plates (a) to (e), Epstein test pieces in the rolling direction and the direction perpendicular to the rolling direction were sampled, and the magnetic properties in each direction were measured. The results are shown in Table 2.
From these materials, the stator 2 of the brushless DC motor having the three-phase four-pole magnetic pole concentrated winding shown in FIG. 2 was produced. The rotor 1 was a surface magnet type. These motors were subjected to a steady rotation test at a rotation speed of 1500 rpm and a torque of 3 Nm, and the efficiency was obtained. Table 2 also shows the efficiency measurement results.
[0052]
[Table 2]

[0053]
As shown in Table 2, when the stator 2 is manufactured from the electromagnetic steel sheet of the present invention to the above-described electric motor, higher efficiency is obtained as compared with a motor manufactured from a conventional unidirectional electromagnetic steel sheet.
[0054]
Example 2
A three-phase four-pole interior magnet type synchronous motor shown in FIG. 3 was fabricated from the same material as in Example 1 above. These motors were subjected to a steady rotation test at a rotation speed of 2500 rpm and a torque of 2 Nm, and the efficiency was obtained. The results are also shown in Table 3.
[0055]
[Table 3]

[0056]
As shown in Table 3, when a stator is manufactured from the electromagnetic steel sheet of the present invention to the above electric motor, higher efficiency is obtained compared to a motor manufactured from a conventional unidirectional electromagnetic steel sheet.
[0057]
【The invention's effect】
According to the split iron core of the present invention, iron loss can be reduced in a stator of a rotating machine using a permanent magnet as a rotor, and a highly efficient rotating machine can be provided as compared with the prior art. Therefore, if this split iron core is applied to a rotating machine, it will greatly contribute to the reduction of energy loss.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing the flow of magnetic flux inside a stator of a rotating machine using a permanent magnet as a stator.
FIG. 2 is a schematic diagram of a surface magnet type brushless DC motor (split core type).
FIG. 3 is a schematic view of a magnet-embedded synchronous motor (split core type).
[Explanation of symbols]
1 Rotor 2 Stator 3 Flow of magnetic flux 4 Flow of magnetic flux

Claims (1)

A split iron core constituting a stator of a rotating machine that uses a permanent magnet as a rotor, wherein the electromagnetic steel sheet constituting the iron core contains Si: 2.0 to 8.0 mass% and Mn : 0.005 to 3.0 mass % , When the magnetic flux densities in the rolling direction and the direction perpendicular to the rolling direction at a magnetizing force of 200 A / m are B _L2 and B _C2 , B _L2 is 1.60 T or more and B _C2 / B _L2 is 0.80 or less, and the maximum magnetization when force 200A / m and in the rolling direction and the rolling direction and at right angles in the frequency 50Hz direction iron loss of the _{W L200 / 50} and _{W C200 / 50 respectively, W C200 / 50 / W L200} / 50 is Ri der 1.4 , split iron core to which the highest magnetic flux density of the electromagnetic steel sheet characterized Rukoto such as the direction of the teeth of the split core.

Images