JP4364487B2 - Rare earth bonded magnet from sheet to film and permanent magnet motor using the same - Google Patents

Description

【００２８】
上式中、Ｒ¹、Ｒ²は同一又は異なって、脂肪族、脂環族若しくは芳香族の炭化水素基を表す。但し、Ｒ¹、Ｒ²の少なくとも何れかは芳香族炭化水素基を表す。本化合物は、少なくとも１個の芳香族基を有することをその特徴とし、具体的には、以下の３群に分類される。（Ａ）脂肪族グリシジルエーテル又は脂環族グリシジルエーテルの芳香族カルボン酸付加物、（Ｂ）芳香族グリシジルエーテルの脂肪族カルボン酸又は脂環族カルボン酸付加物、（Ｃ）芳香族グリシジルエーテルの芳香族カルボン酸付加物。前記各群に属する化合物は、例えば、夫々のグリシジルエーテルに対して所定のカルボン酸を第三級アミン、イミダゾール類、金属エステル系化合物、燐系化合物等から選ばれる反応触媒の存在下，６０〜１２０℃の加熱攪拌しながら、常圧から減圧下で付加することにより調製することができる。
【００２９】
また，希土類磁石粉末は結合剤との結合力を強固にするため，予め室温で固体のエポキシオリゴマ−で表面被覆することが望ましい。また，その平均膜厚は０．１μｍ以下とする。これは，異方性の希土類磁石粉末同士の２次凝集による配向度の低下を防ぐために重要である。更に，希土類磁石粉末へのエポキシオリゴマ−の被覆方法としては，先ず，当該エポキシオリゴマ‐を有機溶媒に溶解し，その後，希土類磁石粉末と湿式混合し，溶媒を除去した当該塊状混合物を解砕する。なお，エポキシオリゴマ‐の架橋密度を高めるためには分子鎖内にもエポキシ基を有するノボラック型エポキシが望ましい。また，前記エポキシオリゴマ‐と架橋する粉末エポキシ硬化剤とはジシアンジアミドおよびその誘導体，カルボン酸ジヒドラジド，ジアミノマレオニトリルおよびその誘導体のヒドラジドの群より選ばれた１種または２種以上などを挙げることができる。これ等は一般に有機溶媒に難溶の高融点化合物であるが，粒子径を数ないし数十μｍに調整したものが好ましい。なお，ジシアンジアミド誘導体としては，例えばｏ−トリルビグアニド，α−２・５−ジメチルビクアニド，α−ω−ジフェニルビグアニド，５−ヒドロキシブチル−１−ビグアニド，フェニルビグアニド，α−，ω−ジメチルビクアニドなどがある。更に，カルボン酸ジヒドラジドとしてはコハク酸ヒドラジド，アジピン酸ヒドラジド，イソフタル酸ヒドラジド，ｐ−アキシ安息香酸ヒドラジドなどがある。これらの硬化剤はコンパウンドに乾式混合によって添加することが望ましい。なお，コンパウンドの成形型への移着を防ぐには，成形型の設定温度よりも高融点の高級脂肪酸，高級脂肪酸アミド，高級脂肪酸金属石鹸類から選ばれる１種または２種以上を０．２ｗｔ．％以下コンパウンドに乾式混合によって添加することが望ましい。
【００３０】
上記，コンパウンドの希土類磁石粉末の含有量は９２ｗｔ．％から９７ｗｔ．％，圧縮成形圧力は４ｔｏｎ／ｃｍ²以上，グリ−ンシ−トの結合剤成分の熱処理が当該エポキシオリゴマ−の反応開始温度以上とし，最終的な圧延では圧延率２％以上，巻き付け限界径８ｍｍ以下とするか，もしくは圧延率１０％以上，巻き付け限界径２ｍｍ以下とすると機械強度との整合性のよい希土類ボンド磁石が得られる。なお，最終的に用いる効率的な小型モ−タのコギングトルク低減のために，グリ−ンシ−トを不等幅としたり，不等肉厚とすることは当該モ−タの設計思想に委ねるところである。しかし，本発明は通常厚さが０．５〜２．０ｍｍ程度のグリ−ンシ−トを圧縮成形するものであるから，カレンダ−リングや押出成形の成型加工時では対応できないところも，柔軟に対応できる利点がある。
【００３１】
一方，短冊状のグリ−ンシ−トを例えば円弧状成形型を用いてスタンピング加工し，必要に応じて加熱処理するとシ−トからフィルムに至る円弧状の希土類ボンド磁石が準備できる。なお，スタンピング加工とは一般には熱可塑性シ−トを加熱・軟化し，プレス成形する方法で，板金プレスと同様のシステムで成型加工するためスタンパブルシ−ト成形とも呼ばれる。（斎藤進六監修，新材料成型加工辞典，Ｐ７７５，産業調査会材料情報センタ−，１９８８）。本発明に掛かる結合剤は熱硬化性エポキシ樹脂を成分とするものであるが，成形加工法から言えば，引用のスタンピング加工が最も類似な方法と考えられるので，スタンピング加工とした。
【００３２】
更に，本発明では，ソフト磁性粉末を含有したグリ−ンシ−トと希土類磁石粉末を含有したグリ−ンシ−トを一体的に成形し，熱処理，圧延するソフト磁性複合フレキシブル磁石を作製することもできる。このような，ソフト磁性複合フレキシブル磁石は接着層なしでソフト磁性層が磁石と一体化するので効率のよい磁気回路を形成するのに有利である。
【００３３】
次に，磁気的に等方性の希土類磁石粉末としてはスピニングカップアトマイゼ−ションによって準備されたＮｄ−Ｆｅ−Ｂ系球状粉末（Ｂ．Ｈ．Ｒａｂｉｎ，Ｂ．Ｍ．Ｍａ，”Ｒｅｃｅｎｔ Ｄｅｖｅｌｏｐｍｅｎｔｓ ｉｎ ＮｄＦｅＢＰｏｗｄｅｒ”１２０ｔｈ Ｔｏｐｉｃａｌ Ｓｙｍｐｏｓｉｕｍ ｏｆ ｔｈｅＭａｇｎｅｔｉｃ Ｓｏｃｉｅｔｙ ｏｆ Ｊａｐａｎ ２３， ２００１）。
【００３４】
メルトスピニング（Ｊ．Ｊ．Ｃｒｏａｔ，Ｊ．Ｆ．Ｈｅｒｂｓｔ，Ｒ．Ｗ．Ｌｅｅ ａｎｄ Ｆ．Ｅ．Ｐｉｎｋｅｒｔｏｎ，Ｊ．Ａｐｐｌ．Ｐｈｙｓ．５５，２０７８， １９８４）によって準備されたＮｄ−Ｆｅ−Ｂ系フレ−ク状粉末（Ｒ．Ｗ．Ｌｅｅ ａｎｄ Ｊ．Ｊ．Ｃｒｏａｔ，ＵＳ−Ｐａｔｅｎｔ ４，９０２，３６１．１９９０），αＦｅ／Ｎｄ−Ｆｅ−Ｂ系フレ−ク状粉末，Ｆｅ₃Ｂ／Ｎｄ−Ｆｅ−Ｂ系フレ−ク状粉末，Ｓｍ−Ｆｅ−Ｎ系フレ−ク状粉末，αＦｅ／Ｓｍ−Ｆｅ−Ｎ系フレ−ク状粉末，などを挙げることができる。なお，それらのフレ−ク状粉末の厚さに対する粒子径の比は４以下とすることが望ましい。
【００３５】
なお，図３は上記スピニングカップアトマイゼ−ション（図３左）とメルトスピニング（図３右）の製造概念図を示す。
【００３６】
次に，磁気的に異方性の希土類磁石粉末としては熱間据込加工（Ｄｉｅ−Ｕｐ−Ｓｅｔｔｉｎｇ）によって準備されたＮｄ−Ｆｅ−Ｂ系粉末（例えば，Ｍ．Ｄｏｓｅｒ，Ｖ．Ｐａｎｃｈａｎａｔｈａｎ；Ｐｕｌｖｅｒｉｚｉｎｇ ａｎｉｓｏｔｒｏｐｉｃ ｒａｐｉｄｌｙ ｓｏｌｉｄｉｆｉｅｄ Ｎｄ−Ｆｅ−Ｂ ｍａｔｅｒｉａｌｓ ｆｏｒ ｂｏｎｄｅｄ ｍａｇｎｅｔ；Ｊ．Ａｐｐｌ．Ｐｈｙｓ．７０（１０），１５，１９９３）。ＨＤＤＲ処理（水素分解／再結合）によって準備された磁気的に異方性のＮｄ−Ｆｅ−Ｂ系粉末，すなわち，Ｎｄ−Ｆｅ（Ｃｏ）−Ｂ系合金のＮｄ₂（Ｆｅ，Ｃｏ）₁₄Ｂ相の水素化（Ｈｙｄｒｏｇｅｎａｔｉｏｎ，Ｎｄ₂［Ｆｅ，Ｃｏ］₁₄ＢＨｘ）、６５０〜１０００℃での相分解（Ｄｅｃｏｍｐｏｓｉｔｉｏｎ，ＮｄＨ₂＋Ｆｅ＋Ｆｅ₂Ｂ）、脱水素（Ｄｅｓｏｒｐｓｉｏｎ）、再結合（Ｒｅｃｏｍｂｉｎａｔｉｏｎ）するＨＤＤＲ処理（Ｔ．Ｔａｋｅｓｈｉｔａ ａｎｄ Ｒ．Ｎａｋａｙａｍａ：Ｐｒｏｃ．ｏｆ ｔｈｅ １０^th ＲＥ Ｍａｇｎｅｔｓ ａｎｄ Ｔｈｅｉｒ Ａｐｐｌｉｃａｔｉｏｎｓ，Ｋｙｏｔｏ，Ｖｏｌ．１，５５１ １９８９）で作製した磁気的に異方性の希土類磁石粉末である。前記粉末の表面を予め光分解したＺｎなど不活性化処理した粉末など（例えば，Ｋ．Ｍａｃｈｉｄａ，Ｋ．Ｎｏｇｕｃｈｉ，Ｍ．Ｎｕｓｈｉｍｕｒａ，Ｙ．Ｈａｍａｇｕｃｈｉ，Ｇ．Ａｄａｃｈｉ，Ｐｒｏｃ．９ｔｈＩｎｔ．Ｗｏｒｋｓｈｏｐ ｏｎ Ｒａｒｅ−Ｅａｒｔｈ Ｍａｇｎｅｔｓ ａｎｄＴｔｈｅｉｒ Ａｐｐｌｉｃａｔｉｏｎｓ，Ｓｅｎｄａｉ，Ｊａｐａｎ，II，８４５ ２０００，或いは，Ｋ．Ｍａｃｈｉｄａ，Ｙ．Ｈａｍａｇｕｃｈｉ，Ｋ．Ｎｏｇｕｃｈｉ，Ｇ．Ａｄａｃｈｉ，Ｄｉｇｅｓｔｓ ｏｆ ｔｈｅ２５^th Ａｎｎｕａｌ ｃｏｎｆｅｒｅｎｃｅ ｏｎ Ｍａｇｎｅｔｃｓ ｉｎ Ｊａｐａｎ，２８ａＣ−６ ２００１）を挙げることができる。なお，それらの磁石粉末の４ＭＡ／ｍパルス着磁後の２０℃における保磁力は１．１ＭＡ／ｍ以上のものが望ましい。
【００３７】
一方，磁気的に異方性の希土類磁石粉末としてはＲＤ（酸化還元）処理によって準備された磁気的に異方性のＳｍ−Ｆｅ−Ｎ系微粉末，前記粉末の表面を予め不活性化処理した粉末を挙げることもでき，前記粉末の４ＭＡ／ｍパルス着磁後の２０℃における保磁力は０．６ＭＡ／ｍ以上のものが望ましい。
【００３８】
上記希土類磁石粉末は単独でも，或いは２種以上の混合系であっても差し支えない。ただし，混合した全希土類磁石粉末の４ＭＡ／ｍパルス着磁後の２０℃における保磁力の平均値が０．６ＭＡ／ｍ以上であることが望ましい。
【００３９】
なお，最終的な圧延後，表面に溶融接着（ホツトメルト接着）型自己融着層を設けることや安定化イソシアナ−トを混合したフィルム形成能を有するポリマ−の１種または２種以上から形成した自己融着層を設けることにより，永久磁石型モ−タへの実装性を高めることも有効である。
【００４０】
上記のようなフレキシブル磁石を円筒枠の内周面に巻きつけ，固定，および多極着磁した環状の磁石を永久磁石界磁とする永久磁石型直流モ−タ。円筒枠の内周面に環状の磁石を備え，半径方向空隙型回転子とする永久磁石型モ−タ。円柱枠の外周面に環状の磁石を備えた表面磁石型回転子を搭載する永久磁石型モ−タなどを挙げることができる。更に，それらは自己融着層で相手材と接合するなど，設計思想によって多様な永久磁石型モ−タに対応することができる。とくに，４ＭＡ／ｍパルス着磁後の室温における最大エネルギ−積（ＢＨ）_maxが１４０ｋＪ／ｍ³以上のシ−トからフィルムに至る希土類ボンド磁石を搭載した永久磁石型モ−タはメルトスピニングによって準備されたＮｄ−Ｆｅ−Ｂ系フレ−ク状粉末−堅い熱硬化性樹脂−圧縮成形から作製した永久磁石型モ−タの次世代型として，とくに小口径で有望であり，４ＭＡ／ｍパルス着磁後の室温における最大エネルギ−積（ＢＨ）_maxが４０ｋＪ／ｍ³以上のフレキシブル磁石を搭載した永久磁石型モ−タはフェライトゴム磁石を使った永久磁石型モ−タの次世代型として有望である。
【００４１】
【実施例】
以下，本発明を実施例により更に詳しく説明する。ただし，本発明は実施例によって限定されるものではない。
【００４２】
（実施例１）
１．材料
本実施例では，４種類の形態の異なる希土類磁石粉末を使用した。すなわち，ＨＤＤＲ処理（水素分解／再結合）によって準備された磁気的に異方性のＮｄ−Ｆｅ−Ｂ粉末（Ｎｄ_12.3Ｄｙ_0.3Ｆｅ_64.7Ｃｏ_12.3Ｂ_6.0Ｇａ_0.6Ｚｒ_0.1）ｐｏｗｄｅｒ−Ａ、スピニングカップアトマイゼ−ションによって準備されたＮｄ−Ｆｅ−Ｂ球状粉末（Ｎｄ_13.3Ｆｅ_62.5Ｂ_6.8Ｇａ_0.3Ｚｒ_0.1）ｐｏｗｄｅｒ−Ｂ，およびメルトスピニングによって準備されたＮｄ−Ｆｅ−Ｂ系フレ−ク状粉末（Ｎｄ₁₂Ｆｅ₇₇Ｃｏ₅Ｂ₆）ｐｏｗｄｅｒ−Ｃ，ＲＤ（酸化還元）したＳｍ₂Ｆｅ₁₇Ｎ₃微粉末ｐｏｗｄｅｒ−Ｄである。また，結合剤システムの構成成分としては室温で固体のノボラック型エポキシオリゴマ−，粒子径１５μｍ以下の粉末状潜在性エポキシ硬化剤，粘着剤を含み予め１００μｍ以下に冷凍粉砕したポリアミド粉末，並びに粒子径１０μｍ以下の滑剤が，この実施例で使用された。なお，ノボラック型エポキシオリゴマ，粉末状潜在性エポキシ硬化剤の化学構造は以下の通りであった。
【００４３】
【化２】

【００４４】
【化３】

【００４５】
なお，固体のエポキシオリゴマ−はｐｏｗｄｅｒ−Ａの配向度向上のため２次凝集するような顆粒状にならないように調整した。なお，調整はオリゴマ−の密度，磁石粉末の平均的な比表面積から平均膜を求めると０．１μｍ以下に調整されるべきであった。また，硬化後の強度は平均膜厚を０．２μｍまで増加しても，殆ど変化することはなかった。
【００４６】
２．希土類ボンド磁石の準備
本発明はｐｏｗｄｅｒ−Ａ、−Ｂ、−Ｃおよび−Ｄのような様々な希土類磁石粉末の１種または２種以上からシ−トからフィルムに至る様々な形態の希土類ボンド磁石を合理的に作製し，効率的な小型モ−タを提供するためになされた。とくに，ｐｏｗｄｅｒ−Ａのようなアキシャル磁界配向した異方性を含む本発明に掛かるシ−トからフィルムに至る環状の希土類ボンド磁石は磁化の前後にシ−トからフィルムに至る磁石をフレ−ムまたはマンドレルに巻きつけることによって得られた。その結果，ラジアル磁界配向の小径に伴う配向度の低下，すなわち磁気特性低下という困難を克服する。
【００４７】
図４（ａ）はｐｏｗｄｅｒ−Ａ、−Ｂ、−Ｃ，−Ｄおよび固体のエポキシオリゴマ−、そして、粉末状潜在性エポキシ硬化剤，および粘着剤を含むポリアミド粉体からフレキシブルなボンド磁石を準備するための工程を示すブロック図である。また，図４（ｂ）は従来の磁気的に等方性の希土類磁石粉末（▲１▼−ｃ）と堅いエポキシ樹脂のような熱硬化性樹脂（▲２▼−ｃ）とともに圧縮成形（▲３▼−ｄ）した磁石を準備するための工程を示すブロック図である。図４（ｂ）は，例えばＦ．Ｙａｍａｓｈｉｔａ，Ｙ．Ｓａｓａｋｉ，Ｈ．Ｆｕｋｕｎａｇａ，Ｉｓｏｔｒｏｐｉｃ Ｎｄ−Ｆｅ−Ｂ Ｔｈｉｎ Ａｒｃ−ｓｈａｐｅｄ Ｂｏｎｄｅｄ Ｍａｇｎｅｔｓ ｆｏｒ Ｓｍａｌｌ ＤＣ Ｍｏｔｏｒｓ Ｐｒｅｐａｒｅｄｂｙ Ｐｏｗｄｅｒ Ｃｏｍｐａｃｔｉｎｇ Ｐｒｅｓｓ ｗｉｔｈ Ｍｅｔａｌ Ｉｏｎ−ｉｍｐｌａｎｔｅｄ ＰｕｎｃｈｅｓＪ．Ｍａｇｎ．Ｓｏｃ．Ｊａｐａｎ，Ｖｏｌ．２５，Ｎｏ．４，ＰＰ．６８３−６８６（２００１）．に記載されている。図４（ａ），（ｂ）のブロック図から明らかなように，本発明例は従来の方法に比較して希土類磁石粉末と結合剤成分のミキシングによってコンパウンドが準備できる。また，コンパウンドの圧縮成形と硬化は同じであり，本発明ではシ−ト状磁石を最終形態とするための圧延およびまたはスタンピング工程が必須工程として存在する。
【００４８】
図４の説明を行う。（Ｍｉｘｉｎｇ：混合， Ｃｏｍｐａｃｔｉｎｇ ｐｒｅｓｓ： 粉末成形，Ｃｕｒｉｎｇ：硬化，Ｒｏｌｌｉｎｇ：圧延，Ｓｔａｍｐｉｎｇ：スタンピング，Ｐｒｅ−ｃｒｕｓｈｉｎｇ：予備粉砕，Ｗｅｔ−ｍｉｘｉｎｇ：湿式混合，Ｅｖａｐｏｒａｔｉｎｇ：蒸発，Ｃｒｕｓｈｉｎｇ：粉砕，Ｓｉｅｖｉｎｇ：分級，Ｄｒｙ−ｂｌｅｎｄｉｎｇ：乾式混合，Ｃｏａｔｉｎｇ：塗装）。
【００４９】
図４（ａ）の本発明例の製造工程に従って，先ず，コンパウンドの調整を説明する。６０℃に加温したΣブレイドミキサ−に所定量の希土類磁石粉末ｐｏｗｄｅｒ−Ａ，Ｂ，ＣおよびＤを５ｋｇ投入し，前記粉末を攪拌しながら，室温で固体のエポキシオリゴマ−の５０％アセトン溶液５０ｇを滴下した。攪拌を続けるとおよそ５ｍｉｎで乾燥したエポキシオリゴマ−を被覆した希土類磁石粉末が得られた。なお，希土類磁石粉末ｐｏｗｄｅｒ−Ａ、Ｂ、ＣおよびＤの表面被覆膜厚がおよそ０．１μｍ以下のとき，ｐｏｗｄｅｒ−Ａ、Ｂ、ＣおよびＤの被覆前後の粉末粒子径分布は殆ど変化しなかった。続いて，前記エポキシオリゴマ−を表面被覆した希土類 磁石粉末に対して３〜７ｗｔ．％の粘着剤２０％含有ポリアミド粒子、粉末状の潜在性エポキシ硬化剤、および潤滑剤（粒子径１０μｍ以下のステアリン酸カルシウム）を添加し，粉末状のコンパウンドとした。それらの粉末状のコンパウンドは潤滑剤によって粉末成形機に供することが可能な粉末流動性を持っていた。
【００５０】
次に、粉末圧縮成形機のフィーダーカップに粉末状のコンパウンドを投入し，成形型キャビティに粉末状のコンパウンドを充填した。ただし，成形型の上下パンチとキャビティ周辺のみ７０〜８０℃に加熱されている。キャビティに充填した磁気的に異方性の希土類磁石粉末を含むコンパウンドは１．４ＭＡ／ｍのアキシャル磁界の中で上下パンチによって圧縮され、脱磁され，圧粉体（グリ−ンシ−ト）を得た。このグリ−ンシ−トは十分なハンドリング性を備えていた。
【００５１】
図５において（Ｎｕｍｂｅｒ ｏｆ ｓｈｏｔｓ：成形回数，Ｗｅｉｇｈｔ：重量）である。
【００５２】
図５は幅６．１，長さ７１ｍｍ，厚さ１．２５ｍｍのＰｏｗｄｅｒ−Ａが９６ｗｔ．％からなるグリ−ンシ−トを粉末成形機で繰返し成形したときの成形回数に対するグリ−ンシ−トの重量（ｇ）を示す特性図である。９０回成形した際のグリ−ンシ−トの重量平均は１．９９１ｇ，その標準偏差は０．００７ｇであり粉末成形性が工業的に可能なコンパウンドが得られる。
【００５３】
次に，上記Ｐｏｗｄｅｒ−Ａが９６ｗｔ．％からなるグリ−ンシ−トを１８０℃で２０ ｍｉｎ加熱し，熱硬化した堅いシ−トとした。図６は厚さ０．８〜２．５ｍｍの磁気的に異方性のＰｏｗｄｅｒ−Ａが９６ｗｔ．％からなるグリ−ンシ−トを熱硬化したのち，シ−トを厚さ方向に４ＭＡ／ｍパルス着磁したときの磁束とシ−トの厚みの関係を示す。更に，このシ−トを直径６０ｍｍ，７０℃に加熱した等速ロ−ルで圧延し，圧延後の厚さと磁束の関係を示した。図中の回帰式のように観測される圧延まえの磁束はシ−ト厚さの減少に応じて低下する。また，圧延したシ−トは圧延まえのシ−ト厚さと比べると磁束の低下が大きく，とくに圧延まえのシ−ト厚さが２ｍｍ以上の場合に著しい。しかし，圧延まえのシ−ト厚みが１．３ｍｍ以下になると，圧延による磁束の低下は２ｍｍ以上の場合よりも抑制され，圧延まえのシ−ト厚さに対する磁束変化の回帰式上に沿った値が得られるようになる。これは，Ｐｏｗｄｅｒ−Ａのような磁気的に異方性の希土類磁石粉末を含むシ−トでは厚さ２ｍｍ以上では圧延によって配向が乱れやすいが，１．３ｍｍ以下になると乱れにくくなるためと言える。従って，Ｐｏｗｄｅｒ−Ａのような磁気的に異方性の希土類磁石粉末を含むシ−トでは１．３ｍｍ以下のものを圧延しシ−トからフィルムに至る本発明に掛かる希土類ボンド磁石とすることが望ましい。
【００５４】
図６において（○：圧延まえＢｅｆｏｒｅ ｒｏｌｌｉｎｇ，●：圧延後Ｒｏｌｌｉｎｇ ｏｕｔ，Ｔｈｉｃｋｎｅｓｓ：厚み，Ｆｌｕｘ：磁束，Ｒ²：相関係数）である。
【００５５】
図７において（○：圧延まえＢｅｆｏｒｅ ｒｏｌｌｉｎｇ，●：圧延後Ｒｏｌｌｉｎｇ ｏｕｔ，Ｔｈｉｃｋｎｅｓｓ：厚み，Ｆｌｕｘ：磁束，Ｒ²：相関係数）である。
【００５６】
図７は９５ｗｔ．％のＰｏｗｄｅｒ−Ａの１０％をＰｏｗｄｅｒ−Ｄに置換した磁気的に異方性の希土類磁石粉末を含むシ−トの厚みと圧延による磁束の変化を示す特性図である。Ｐｏｗｄｅｒ−Ｄは粉末粒子径が２〜３μｍと小さいが，１．３ｍｍ以下のシ−トで圧延率が少ない場合には圧延によって磁束が増加する傾向も観測される。図８は９５ｗｔ．％のＰｏｗｄｅｒ−Ａの０から最大５０％をＰｏｗｄｅｒ−Ｄに置換した磁気的に異方性の希土類磁石粉末を含む厚さ１．１７ｍｍのシ−ト磁石（成形圧力４００ＭＰａ）において，Ｐｏｗｄｅｒ−Ｄの置換率に対する磁石密度を示す特性図である。Ｐｏｗｄｅｒ−Ｄのように粉末粒子径が２〜３μｍと小さい場合，置換量が１０％を越えると磁石密度は低下する。そこで，密度低下の少ないＰｏｗｄｅｒ−Ｄの置換率５，１０％とした場合のシ−ト磁石の厚みと磁束の関係を図９に示す。図から明らかなように，磁石密度は同等にも拘らず，磁石の厚さが１ｍｍ以下になるとＰｏｗｄｅｒ−Ｄの置換率５，１０％としたシ−トからフィルムに至る磁石の磁束はＰｏｗｄｅｒ−Ａのみのシ−ト磁石よりも高い磁束が得られる。図から明らかなように，この傾向は薄いフィルム磁石になるほど顕著となる。したがって，Ｐｏｗｄｅｒ−Ａの平均粉末粒子径は８０μｍと大きいため，１ｍｍ以下の薄いシ−トからフィルムに至る希土類ボンド磁石を準備する際には，Ｐｏｗｄｅｒ−Ａのような粉末粒子径の大きな希土類磁石粉末を単独で使用するよりも，Ｐｏｗｄｅｒ−Ｄのような小さな粉末粒子径の希土類磁石粉末を磁石密度が低下しない１０％以下の範囲で併用することが好ましい。
【００５７】
図８において（Ｗｅｉｇｈｔ ｆｒａｃｔｉｏｎ ｏｆ Ｐｏｗｄｅｒ−Ｄ：Ｐｏｗｄｅｒ−Ｄの割合，Ｄｅｎｓｉｔｙ：密度）である。
【００５８】
図１０は厚さ１．３ｍｍ以下のシ−トの圧延率に対する磁束変化を示す特性図である。ただし，何れも希土類磁石粉末は９６ｗｔ．％含まれている。図のように，圧延率が概ね１５％以下であればシ−トに含まれる希土類磁石粉末の形状（フレ−ク状，球状など）に拘らず１０％を越える磁束変化は起こらない。しかし，１５％を越えるとメルトスピニングによるフレ−ク状の希土類磁石粉末であるＰｏｗｄｅｒ−Ｃでは磁束が増加に転じ，スピニングカップアトマイゼ−ションによる球状の希土類磁石粉末であるＰｏｗｄｅｒ−Ｂも磁束は増加に転じる。しかし，磁気的に異方性の希土類磁石粉末Ｐｏｗｄｅｒ−Ａは磁束が増加に転じることがない。磁気的に等方性のＰｏｗｄｅｒ−Ｂ，−Ｃは圧延率の増加に伴う密度の上昇が磁束を増加に転じさせたものと言える。
【００５９】
図９において（Ｔｉｃｋｎｅｓｓ：厚さ，Ｉｎｃｒｅａｄｉｎｇ ｒａｔｅ ｏｆ ｆｌｕｘ：磁束の増加率）である。
【００６０】
図１０において（□：Ｐｏｗｄｅｒ−Ａ，●：Ｐｏｗｄｅｒ−Ｂ，×：Ｐｏｗｄｅｒ−Ｃ，Ｒｏｌｌｉｎｇ ｒａｔｅ：圧延率，Ｃｈａｎｇｅｓ ｉｎ ｆｌｕｘ：磁束の変化）である。
【００６１】
図１１（ａ）はＰｏｗｄｅｒ−Ａを９６ｗｔ．％含むシ−トを圧延し，厚さ２００μｍのフィルム磁石，図１１（ｂ）は前記フィルム磁石を直径０．８ｍｍのマンドレルに巻きつけた様子を示す外観図である。図のように，本発明に掛かるシ−トからフィルムに至る希土類ボンド磁石は直径１ｍｍ以下のマンドレルに容易に巻きつけ固定することができる。とくに，フィルム形成能の良好な自己融着層を付与した本発明の希土類ボンド磁石を回転軸に巻きつけて焼き付け固定すると図１１（ｂ）のような直径１ｍｍ程度のラジアル異方性希土類ボンド磁石を備えた表面磁石型回転子を準備することができる。このように，本発明に掛かるフィルム磁石はスパッタリングによる薄膜の希土類磁石，研削加工によって作製した厚膜の希土類焼結磁石や密度の低い圧縮成形希土類ボンド磁石や射出成形希土類ボンド磁石よりも機械的に脆弱でなく，打抜き，巻きつけなどの加工や接着などが容易であるから，ミリサイズモ−タの磁石としても優れていると言える。
【００６２】
図１２はＰｏｗｄｅｒ−Ａを９７ｗｔ．％含む幅４ｍｍ，長さ１５．５ｍｍ，厚さ０．９ｍｍの短冊状グリ−ンシ−トを８０℃の円弧状成形型を用いて約４００ＭＰａの圧力でスタンピング加工し，更に１８０℃で１５ｍｉｎの加熱硬化処理をした最大厚さ０．９ｍｍ，内半径３．５５ｍｍ，外半径３．６５ｍｍのラジアル異方性円弧状磁石の外観図である。なお，スタンピング加工とは一般には熱可塑性シ−トを加熱・軟化し，プレス成形する方法で，板金プレスと同様のシステムで成型加工するためスタンパブルシ−ト成形とも呼ばれる。（斎藤進六監修，新材料成型加工辞典，Ｐ７７５，産業調査会材料情報センタ−，１９８８）。本発明に掛かる結合剤は熱硬化性エポキシ樹脂を成分とするものであるが，成形加工法から言えば，引用のスタンピング加工が最も類似な方法と考えられるので，図１２の加工をスタンピング加工とした。
【００６３】
以上のように，本発明に掛かるシ−トからフィルムに至る圧延または／およびスタンピングで最終形態に変換した希土類ボンド磁石は磁気的に異方性の希土類磁石粉末，および等方性のフレ−ク状から球状に至る希土類磁石粉末ｐｏｗｄｅｒ−Ｂ，−Ｃ，Ｐｏｗｄｅｒ−Ｄの１種または２種以上から準備することができ，希土類ボンド磁石としての磁気特性と磁石としての形態を多様化させることができる。
【００６４】
３．耐久性
準備されたそれらの磁石は張力と伸張などの力学的性質と減磁曲線から求められる磁気特性や不可逆磁束損失について調べられた。図１３は希土類磁石粉末を９６ｗｔ．％含む１．１７ｍｍ厚シ−ト磁石の張力と伸長の温度依存性を示す特性図である。ただし，図の実線は張力，破線は伸長を表している。図のように希土類磁石粉末の種類に拘らず低温では張力が高く，高温では伸長が大きくなる。しかし，何れも室温付近の張力は希土類磁石粉末を９６ｗｔ．％含むにも拘らず，フェライト磁石粉末（▲１▼−ａ）／フレキシブル系（ゴム，熱可塑性エラストマ−）（▲２▼−ａ）／カレンダ−リングまたは押出（▲３▼−ａ）の連携で準備された従来磁石と同等の５０−１００ｋｇｆ／ｃｍ２の張力と２〜８％程度の伸長を備えている。
【００６５】
図１３において（Ｔｅｍｐｅｒａｔｕｒｅ：温度，Ｔｅｎｓｉｌｅ ｓｔｒｅｎｇｔｈ：張力，Ｅｌｏｎｇａｔｉｏｎ：伸長）である。
【００６６】
図１４（ａ），（ｂ）は本発明に掛かる１．１７ｍｍ厚シ−ト希土類ボンド磁石を１２０℃，１０００ｈｒｓ暴露したときの張力，伸長の変化を示す特性図である。図のように，長期間高温暴露では張力は殆ど変化しないか，または次第に増加する。張力が増加する場合には，それに対応して伸長が低下する。希土類磁石粉末の形態に拘らず，本発明に掛かるシ−トからフィルムに至る希土類ボンド磁石は力学的性質耐久性からみると実用に耐える水準にある。
【００６７】
図１５は本発明に掛かる圧延率６〜８％で圧延した１．１７ｍｍ厚のシ−ト状希土類ボンド磁石を１２０℃，１０００ｈｒｓ暴露したときの磁石の厚み変化を示す特性図である。図のように，長期間高温暴露では厚みなど磁石の寸法は殆ど変化しない。メルトスピニングによるフレ−ク状の希土類磁石粉末を含むシ−ト磁石の場合にも，寸法変化は高々１％未満である。したがって，希土類磁石粉末の形態に拘らず，本発明に掛かるシ−トからフィルムに至る希土類ボンド磁石は寸法安定性からみると小型で効率的なモ−タに実装しても実用に耐える水準にある。
【００６８】
図１４において（Ｅｘｐｏｓｕｒｅ ｔｉｍｅ：放置時間，Ｔｅｎｓｉｌｅ ｓｔｒｅｎｇｔｈ：張力，Ｅｌｏｎｇａｔｉｏｎ：伸長，●：Ｐｏｗｄｅｒ−Ａ，◯：Ｐｏｗｄｅｒ−Ｂ，◇：Ｐｏｗｄｅｒ−Ｃ）である。
【００６９】
図１５において（Ｅｘｐｏｓｕｒｅ ｔｉｍｅ：放置時間，Ｔｅｎｓｉｌｅ ｓｔｒｅｎｇｔｈ：張力，Ｅｌｏｎｇａｔｉｏｎ：伸長，●：Ｐｏｗｄｅｒ−Ａ，◯：Ｐｏｗｄｅｒ−Ｂ，◇：Ｐｏｗｄｅｒ−Ｃ）である。
【００７０】
図１６は本発明に掛かる７０〜８０℃で４００ＭＰａの圧力でスタンピングした図１２に示す最大厚さ０．９０ｍｍ厚のＰｏｗｄｅｒ−Ａを９７ｗｔ．％含む円弧状希土類ボンド磁石を１２０℃，１０００ｈｒｓ暴露したときの磁石の厚み変化を示す特性図である。図のように，スタンピング加工による応力緩和によって約１５０ｈｒｓまでの間に７％程度の厚み変化が観測される。しかし，スタンピング加工後に１８０℃，２０ｍｉｎの熱処理を施すことで，応力緩和によると考えられる寸法変化はなくなり，長期間高温暴露の厚みなど磁石の寸法は殆どなくなる。したがって，本発明に掛かるシ−トからフィルムに至る希土類ボンド磁石は圧延ばかりか，スタンピング加工であっても小型で効率的なモ−タに実装しても実用に耐える寸法安定性を確保している。とくに，スタンピング加工後の熱処理は初期的な寸法安定性の確保に有効である。
【００７１】
図１６において（Ｅｘｐｏｓｕｒｅ ｔｉｍｅ： 暴露時間，Ｃｈａｎｇｅｓｉｎ ｔｈｉｃｋｎｅｓｓ：厚さ変化，Ａｆｔｅｒ ｓｔａｍｐｉｎｇ：スタンピング後，Ｓｔａｍｐｉｎｇ ａｎｄ ａｎｎｅａｌｉｎｇ：スタンピングと熱処理）である。
【００７２】
図１７は６．１ｍｍ幅，２５ｍｍ長，１．１７ｍｍ厚の本発明に掛かる希土類ボンド磁石初期不可逆磁束損失を示す特性図である。初期不可逆磁束損失は希土類磁石粉末の保磁力と保磁力の温度係数に強く依存するが，保磁力１．１ＭＡ／ｍ，保磁力の温度係数−０．５％／℃程度のＰｏｗｄｅｒ−Ａ（異方性ＮｄＦｅＢ系ＨＤＤＲ粉末）であれば，１００℃程度までの減磁はメルトスピニングによるフレ−ク状の希土類磁石粉末を含むシ−ト磁石と同等の磁気安定性を示す。また，スピニングカップアトマイズドによる球状粉末はメルトスピニングによるフレ−ク状の希土類磁石粉末を含むシ−ト磁石と１８０℃の高温領域まで同等の磁気安定性を示す。したがって，希土類磁石粉末の形態に拘らず，本発明に掛かるシ−トからフィルムに至る希土類ボンド磁石は磁気安定性からみると小型で効率的なモ−タに実装しても実用に耐える水準にある。
【００７３】
図１７において（Ｔｅｍｐｅｒａｔｕｒｅ：温度，Ｉｎｉｔｉａｌ ｉｒｒｅｖｅｒｓｉｂｌｅ ｆｌｕｘ ｌｏｓｓ：初期不可逆磁束損失，：Ｐｏｗｄｅｒ−Ａ，○：Ｐｏｗｄｅｒ−Ｂ，◇：Ｐｏｗｄｅｒ−Ｃ）である。
【００７４】
なお，本発明で対象とする殆どの電気電子機器に搭載されたときのモ−タ運転中の磁石温度は１００℃以下である。したがって本発明に掛かるシ−トからフィルムに至る希土類ボンド磁石は，ｐｏｗｄｅｒ−Ａ，Ｂ，およびＣに拘らず，一般に小型ＤＣモ−タの運転温度領域における磁気安定性を備えている。ただし，このような磁気安定性を確保するには，希土類系磁石粉末の室温で４ＭＡ／ｍのパルス着磁後の保磁力が６００ｋＡ／ｍ以上であることが望ましい。なお，ｐｏｗｄｅｒ−Ａから準備される異方性のシ−トからフィルムに至る希土類ボンド磁石の場合は保磁力の温度係数が−０．５％／℃程度と，一般の希土類系磁石粉末−０．４％／℃よりも大きく，その分ｐｏｗｄｅｒ−Ａのような異方性の希土類系磁石粉末の場合は，室温で４ＭＡ／ｍのパルス着磁後の保磁力が６００ｋＡ／ｍ以上であること１．１ＭＡ／ｍ以上であることが望ましい。なお，ｐｏｗｄｅｒ−Ａのような異方性の希土類系磁石粉末から準備される本発明に掛かるシ−トからフィルムに至る希土類ボンド磁石は異方性の堅いエポキシ樹脂ボンド磁石のように長期の磁束損失が問題になるかも知れない。ところが、最近，その困難がｐｏｗｄｅｒ−Ａのような異方性の希土類磁石粉末への表面処理で克服できると報告される。例えば，Ｋ．Ｍａｃｈｉｄａ，Ｋ．Ｎｏｇｕｃｈｉ，Ｍ．Ｎｕｓｈｉｍｕｒａ，Ｙ．Ｈａｍａｇｕｃｈｉ，Ｇ．Ａｄａｃｈｉ，Ｐｒｏｃ．９ｔｈ Ｉｎｔ．Ｗｏｒｋｓｈｏｐ ｏｎ Ｒａｒｅ−Ｅａｒｔｈ Ｍａｇｎｅｔｓ ａｎｄＴｔｈｅｉｒ Ａｐｐｌｉｃａｔｉｏｎｓ，Ｓｅｎｄａｉ，Ｊａｐａｎ，（II），８４５（２０００）。或いは，Ｋ．Ｍａｃｈｉｄａ，Ｙ．Ｈａｍａｇｕｃｈｉ，Ｋ．Ｎｏｇｕｃｈｉ，Ｇ．Ａｄａｃｈｉ，Ｄｉｇｅｓｔｓ ｏｆ ｔｈｅ２５^th Ａｎｎｕａｌ ｃｏｎｆｅｒｅｎｃｅ ｏｎ Ｍａｇｎｅｔｃｓ ｉｎ Ｊａｐａｎ，２８ａＣ−６（２００１）などの引用文献によれば，ｐｏｗｄｅｒ−Ａのような磁気的に異方性の希土類磁石粉末を堅いエポキシボンド磁石で９８０ＭＰａ程度の高い圧縮圧力で成形した磁石である。引用文献と比べると、本発明は，それらの４０％程度という低い３８０ＭＰａの圧縮圧力でｐｏｗｄｅｒ−Ａから準備される希土類ボンド磁石を作ることができるので、ｐｏｗｄｅｒ−Ａの圧縮時の破壊，また，それに伴って発生する新生面は減少する。したがって、１００℃以下の運転温度領域でｐｏｗｄｅｒ−Ａから準備されるシ−トからフィルムに至る希土類ボンド磁石の長期磁束損失の一層の減少は期待される。
【００７５】
４．磁石の磁気特性とモ−タ特性
図１８はｐｏｗｄｅｒ−Ａと−Ｂから準備される本発明に掛かるシ−トからフィルムに至る希土類ボンド磁石の典型的な減磁曲線、およびＢ−Ｈ曲線を，本発明で比較対象とする代表的な磁石であるフェライト系磁石粉末（▲１▼−ａ）／フレキシブル系（ゴム，熱可塑性エラストマ−）（▲２▼−ａ）／カレンダ−リングまたは押出成形（▲３▼−ａ）の連携で作製した磁石，および磁気的に等方性の希土類磁石粉末ｐｏｗｄｅｒ−Ｃ（▲１▼−ｃ）と堅いエポキシ樹脂（▲２▼−ｃ）とともに圧縮成形（▲３▼−ｄ）した磁石と比較して示す特性図である。ただし，試験片はそれぞれ１．１ｍｍ厚、７．５ｍｍ幅、７．５ｍｍ長である。図中の付番１，２はｐｏｗｄｅｒ−Ａ、Ｂから準備された本発明に掛かるシ−トからフィルムに至る典型的な希土類ボンド磁石，３および４は、従来のＮｄ−Ｆｅ−Ｂボンド磁石とフェライトゴム磁石である。なお，すべての測定は４ＭＡ／ｍのパルス磁場の下での磁化の後に実行された。また，比較された磁石は小型直流モ−タや小型ブラシレスモ−タに一般的に適用されている磁石である。
【００７６】
図から明らかなように，従来の典型的な磁石の特性３，４の領域に比べて，本発明に掛かる典型的な磁石１，２の特性領域は，明らかにモ−タの電機子鉄心との空隙への静磁界を高めることが了解される。とくに図１８のように本発明に掛かるｐｏｗｄｅｒ−Ａを９７ｗｔ．％含む磁石（密度５．８４Ｍｇ／ｍ³）の（ＢＨ）_maxは１４０ｋＪ／ｍ³に達し，磁気的に等方性の希土類系磁石粉末▲１▼−ｃ（ｐｏｗｄｅｒ−Ｃ）と堅いエポキシ樹脂（▲２▼−ｃ）とともに圧縮成形（▲３▼−ｄ）した磁石の（ＢＨ）_max８０ｋＪ／ｍ³と比較して１．７５倍高い。また本発明に掛かるｐｏｗｄｅｒ−Ｂを９７ｗｔ．％含む磁石（５．４５Ｍｇ／ｍ³）の（ＢＨ）_maxも４０ｋＪ／ｍ³が得られ、従来のフェライトゴム磁石と比較して３倍以上高い。
【００７７】
上記で示されたように、本発明に掛かる磁石には環状磁石を形成するための良い巻きつけ性と磁気特性がある。また，スタンピングによって例えば薄肉の円弧状形態に変換することもできる。例えば，（ＢＨ）_max１４０ｋＪ／ｍ³を示したＰｏｗｄｅｒ−Ａを９７ｗｔ．％含む磁石は直径０．８ｍｍのマンドレルに巻きつけできる。
【００７８】
図１９は環状磁石の直径と磁石のラジアル方向の（ＢＨ）_maxの関係を示す。図において，比較例２はＳｍ−Ｃｏ系希土類磁石粉末（▲１▼−ｃ）を堅い熱可塑性樹脂（▲２▼−ｂ）とともに射出成形（▲３▼−ｃ）したラジアル異方性磁石であり，環状磁石の直径とともに希土類磁石粉末の配向度が低下し，それに伴って（ＢＨ）_maxが減少する。一方，比較例１のように磁気的に等方性のメルトスピニングによるフレ−ク状の希土類磁石粉末▲１▼−ｃ（ｐｏｗｄｅｒ−Ｃ）を堅いエポキシ樹脂（▲２▼−ｃ）とともに圧縮成形（▲３▼−ｄ）した磁石の（ＢＨ）_maxは環状磁石の直径に依存することなく６０〜８０ｋＪ／ｍ³という値が得られる。
【００７９】
しかしながら，直径５ｍｍ以下の環状磁石，特に環状自社君の肉厚が２００μｍとフィルム状となるまで小径化することは粉末成形から困難である。これに対して，本発明例に示すように，本発明例では厚さ２００μｍのフィルム磁石を環状に形成することで，小口径で且つ高（ＢＨ）_maxの環状磁石を提供することができる。このように，本発明は希土類ボンド磁石による効率的な小型モ−タへの代表的な提案の一つとして，本発明者らによる特公平６−８７６３４号公報，すなわち，電機子鉄心と対向した空隙に強力な静磁界をつくるため磁気的に等方性のＲ−Ｆｅ−Ｂ（ＲはＮｄ／Ｐｒ）希土類磁石粉末▲１▼−ｃと堅いエポキシ樹脂▲２▼−ｃとを圧縮成形▲３▼−ｃした外径２５ｍｍ以下，密度５Ｍｇ／ｍ³以上の環状希土類ボンド磁石を多極着磁した構成の永久磁石型モ−タの次世代型高性能モ−タを提供することができる。
【００８０】
次に，磁気的に等方性のスピニングカップアトマイゼ−ションによる球状の希土類磁石粉末Ｐｏｗｄｅｒ−Ｂを９４ｗｔ．％含む（ＢＨ）_max４０ｋＪ／ｍ³，１．１７ｍｍ厚，６．１ｍｍ幅のシ−ト磁石をリング形状に変換して永久磁石界磁にしたときの直流モ−タの特性を図２０に示す。なお，モ−タは図２１のような外観で，直径は２４ｍｍ，高さは１２．５ｍｍである。図のように（ＢＨ）_max１２ｋＪ／ｍ³，１．１７ｍｍ厚，６．１ｍｍ幅のフェライトゴム磁石を界磁とした場合に比べ，消費電流が１／３削減できる効果を奏する。
【００８１】
図２０において（Ｔｏｒｑｅｕ：トルク，Ｃｕｒｒｅｎｔ：電流，Ｒｏｔａｔｉｎｇ ｓｐｅｅｄ： 回転数，Ｍｅｃｈａｎｉｃａｌ ｏｕｔｐｕｔ： 機械出力，Ｅｆｆｉｃｉｅｎｃｙ：効率，Ｃｏｎｖｅｎｔｉｏｎａｌ ｆｅｒｒｉｔｅ： 従来のフェライト）である。
【００８２】
図２２において（Ｍａｇｎｅｄｔｉｚｉｎｇ ｆｉｅｌｄ：着磁界，Ｉｍｐｒｏｖｅｍｅｎｔ ｏｆ ｆｌｕｘ ｒａｔｉｏ：磁束増加率，Ｃｏｍｐａｒｉｓｏｎ ｗｉｔｈ Ｐｏｗｄｅｒ−Ｂ：Ｐｏｗｄｅｒ−Ｂとの比較，Ｃｏｍｐａｒｉｓｏｎ ｗｉｔｈ ｃｏｎｖｅｎｔｉｏｎａｌ Ｎｄ−Ｆｅ−Ｂ：従来のＮｄ−Ｆｅ−Ｂとの比較）である。
【００８３】
図２２は磁気的に等方性のスピニングカップアトマイゼ−ションによる球状の希土類磁石粉末Ｐｏｗｄｅｒ−Ｂを９４ｗｔ．％含む（ＢＨ）_max ４０ｋＪ／ｍ³，１．１７ｍｍ厚シ−ト磁石に対する（ＢＨ）_max１４０ｋＪ／ｍ³を示したＰｏｗｄｅｒ−Ａを９７ｗｔ．％含む１．１７ｍｍ厚のシ−ト磁石の着磁界に対する磁束の増加率，磁気的に等方性のＲ−Ｆｅ−Ｂ（ＲはＮｄ／Ｐｒ）希土類磁石粉末▲１▼−ｃと堅いエポキシ樹脂▲２▼−ｃとを圧縮成形▲３▼−ｃした従来の典型的な（ＢＨ）_max８０ｋＪ／ｍ³，１．１７ｍｍ厚の板状希土類ボンド磁石に対するする（ＢＨ）_max１４０ｋＪ／ｍ³を示したＰｏｗｄｅｒ−Ａを９７ｗｔ．％含む１。１７ｍｍ厚のシ−ト磁石の着磁界に対する磁束の増加率を示す特性図である。図のように，着磁界１．５ＭＡ／ｍ以上，好ましくは２ＭＡ／ｍ以上で本発明に掛かるシ−トからフィルムに至る希土類ボンド磁石を磁化すると，それぞれ１．６倍，１．３倍量の磁束が得られる。実際に図１２に示したスタンピング加工し，更に１８０℃で１５ｍｉｎの加熱硬化処理をした最大厚さ０．９ｍｍ，内半径３．５５ｍｍ，外半径３．６５ｍｍのラジアル異方性円弧状磁石を永久磁石界磁とした直流モ−タの誘起電圧は，磁気的に等方性のＲ−Ｆｅ−Ｂ（ＲはＮｄ／Ｐｒ）希土類磁石粉末▲１▼−ｃと堅いエポキシ樹脂▲２▼−ｃとを圧縮成形▲３▼−ｃした従来の典型的な希土類ボンド磁石を永久磁石界磁とした図２３のような直流モ−タの誘起電圧０．２１８ｍＶ／ｒｐｍの１．３６倍，０．２９６ｍＶ／ｒｐｍを示した。
【００８４】
ところで，本発明に掛かる直流モ−タのように電機子鉄心と界磁磁石との空隙磁束密度を増加させると一般的にコギングトルクの増大を招くことがある。ここで言うコギングトルクとは界磁と対向する電機子の外周表面に電機子鉄心ティ−スとスロットが存在するため、電機子の回転に伴ってパ−ミアンス係数Ｐｃが変化することによるトルク脈動である。本発明に掛かる磁石のように高い（ＢＨ）_maxの磁石を実装したモ−タではコギングトルクが増大するため、モ−タの振動や騒音の増加要因となったり、位置制御の精度に障害が発生する原因となることがある。コギングトルクについては，当該モ−タの設計思想に委ねるところである。しかし，本発明に掛かるシ−トからフィルムに至る希土類ボンド磁石は最終的に用いる効率的なモ−タのコギングトルク低減のために，予めグリ−ンシ−トを不等幅としたり，不等肉厚とすることで，電機子鉄心と界磁との空隙をより正弦波状に近づけ，コギングトルクの増加を抑制する手段を容易に採用することができる。これは，カレンダ−リングや押出成形など，従来のシ−ト磁石の成型加工では合理的な対応ができない。しかし，本発明は粉末状のコンパウンドを通常では，厚さ０．５〜２．５ｍｍ程度のグリ−ンシ−トに圧縮成形するものであるから，モ−タの設計思想に従って柔軟な形状対応を採ることができる。
【００８５】
なお，本発明に掛かる粉末状のコンパウンドにおいて，希土類磁石粉末に代えて飽和磁化１．３Ｔ以上のＦｅ，Ｆｅ−Ｎｉ，Ｆｅ−Ｃｏ，Ｆｅ−Ｓｉ，Ｆｅ−Ｎ，Ｆｅ−Ｂの群から選ばれる１種または２種以上のソフト磁性粉末のコンパウンドを調整し，グリ−ンシ−トとしたものを成形型キャビティに装填し，然る後，本発明に掛かる粉末状のコンパウンドをキャビティに充填して圧縮成形する。或いは，結合剤成分の一部のみを先に圧縮し，然る後，本発明に掛かる粉末状のコンパウンドをキャビティに充填して圧縮成形する。すると，異種機能をもったグリ−ンシ−トの複合体が得られる。この複合体を熱処理，圧延するとバックヨ−ク付きのシ−トからフィルムに至る希土類ボンド磁石や熱溶着性をもった磁石が得られる。さらに，安定化イソシアナ−トを混合した，例えば下記構造（化３）のようなフィルム形成能を有するポリマ−の１種または２種以上の自己融着層を磁石表面に予め形成し，磁石端部や他の部材との接合に利用することもできる。
【００８６】
【化４】

【００８７】
【発明の効果】
以上のように，本発明は新規な概念の導入により鋭意研究した結果，高い生産性で希土類磁石粉末の種類を選ばずシ−トからフィルムに至る希土類ボンド磁石の製造方法を提供できる。とくに，本発明のシ−トからフィルムに至る希土類ボンド磁石は，従来の成形加工方法（カレンダ−リング，押出成形）などのように２００℃を越える成形加工が不要で，不可逆磁束損失などの熱安定性を兼備えた希土類磁石粉末本来の高い磁気性能をモ−タ性能に反映させることができる。したがって，フェライト磁石や磁気的に等方性のＮｄ−Ｆｅ−Ｂ系希土類ボンド磁石を搭載した従来の小型モ−タを上回る効率的な小型モ−タを高い競争力で提供することができる。よって，電気電子機器への寄与ばかりか，幅広い普及によって電力消費削減や省資源化に効果を奏することが期待される。
【図面の簡単な説明】
【図１】ボンド磁石作製における３大要素技術，すなわち磁石粉末，結合剤システム，成形加工方法の連携を示す概念図
【図２】小型モ−タの断面構成図
【図３】スピニングカップアトマイゼ−ション（左）とメルトスピニング（右）の製造概念図
【図４】磁石を準備するための工程図
【図５】粉末成形性をグリ−ンシ−トの重量変化で示す特性図
【図６】シ−トからフィルムに至る磁石の厚みと磁束の関係を示す特性図
【図７】異種希土類磁石粉末を混合したシ−トからフィルムに至る磁石の厚みと磁束の関係を示す特性図
【図８】異種粉末の混合率と密度の関係を示す特性図
【図９】厚さと磁束増加率の関係を示す特性図
【図１０】圧延率と磁束変化を示す特性図
【図１１】フィルム磁石と小口径磁石回転子の外観図
【図１２】シ−トスタンピング後の薄肉円弧状磁石の外観図
【図１３】張力，伸長の温度依存性を示す特性図
【図１４】長期高温暴露における張力，伸長変化を示す特性図
【図１５】シ−ト磁石の長期高温暴露における寸法変化を示す特性図
【図１６】円弧状磁石の長期高温暴露における寸法変化を示す特性図
【図１７】初期不可逆磁束損失を示す特性図
【図１８】減磁曲線を示す特性図
【図１９】環状磁石の径と（ＢＨ）ｍａｘの関係を示す特性図
【図２０】直流モ−タの特性図
【図２１】リング状に巻きつけた磁石を界磁とした直流モ−タの外観図
【図２２】着磁界に対する磁束増加率を示す特性図
【図２３】円弧状磁石を界磁とした直流モ−タの外観図
【符号の説明】
１ フィルム磁石
２ 回転軸
３ 電気子巻線
４ 軸受[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rare earth magnet powder, a binder comprising a thermosetting resin composition, a rare earth bonded magnet ranging from a sheet whose flexibility is controlled by powder molding and rolling or / and stamping to a film having a thickness of 200 μm or less. The present invention relates to an efficient method for manufacturing a permanent magnet type motor. For example, the estimated number of small motors produced from 1992 to 2000 has already exceeded 2.4 to 4.7 billion. The increase in production of four types of DC motors, brushless motors, stepping motors, and ironless core motors was particularly remarkable, increasing 2.6 billion from 1992 to 2000. In addition, an average annual growth rate of 9% can be estimated in the future. However, the production numbers of small induction motors and small synchronous motors are gradually decreasing. This trend suggests the development of efficient small motors with high performance magnets in the small motor industry and the high demand for efficient small motors in the electrical and electronic equipment field. About 70% of the small motors produced are direct current motors. In general small DC motors, ferrite rubber magnets are used. In high performance small DC motors, Nd-Fe-B flake rare earth magnet powders prepared by melt spinning are hard like epoxy resin. Currently, annular magnets compression-molded with thermosetting resins are mainly used.
[0002]
On the other hand, according to statistics from the Ministry of Economy, Trade and Industry and the Agency for Natural Resources and Energy, the total power consumption in Japan in 2000 was approximately 950 billion kWh. Estimating from the data, it is estimated that the power consumed by the motor exceeds 50% of the total domestic demand. The power consumption of a motor is not necessarily a large capacity power motor. For example, the power consumption of a 2.5 inch HDD spindle motor exceeds 50% of the power consumption of the PC in an idle state. (J. G. W. West, Power Engineering J. April 77, 1994). That is, for small motors, their power consumption is a few tens of watts at most. However, considering the high demand in the field of advanced devices such as electrical and electronic equipment, wide use and widespread use of efficient small motors are strongly necessary from the viewpoint of environmental conservation and resource saving. The present invention provides a novel efficient small motor for use in various advanced device devices mainly composed of the above efficient small motor, and a novel rare earth bonded magnet from a sheet to a film adapted thereto. It relates to a manufacturing method.
[0003]
[Prior art]
Small motors used in various advanced devices are required to be small, high output, or highly efficient as the motor size is further reduced as the equipment becomes smaller and lighter. Permanent magnet type motors have become widespread since the 1960s because the application of magnets has led to a reduction in motor loss, which in turn has been effective in the production of efficient small motors. In the development of such a small motor, in the case of a bonded magnet in which magnet powder is hardened with a binder, the magnet powder, the binder system, and the molding method are equally important as the three major elements.
[0004]
Regarding the above-mentioned bonded magnets widely used in small motors, Hirosawa, Tomizawa et al., Recent Progress in Research and Development Related to Bonded Rare-Erth Permanent Magnets, Journal of Applied Magnetics Society of Japan, Vol. 21, no. 4-1, PP. 161-167 (1997) briefly explains. Therefore, using FIG. 1 based on the cited document, the three major element technologies in bond magnet production, that is, the cooperation of magnet powder, binder, and molding method will be described.
[0005]
First, the magnetic powder (1) is ferrite (1) -a, alnico (1) -b, rare earth (1) -c, and the binder (2) is flexible (rubber, thermoplastic elastomer). (2) -a, rigid thermoplastic resin (2) -b, rigid thermosetting resin (2) -c, processing method (3) as calendar ring / extrusion molding (3) -a, injection molding (3) ▼ -b, compression molding ▲ 3 ▼ -c. These linkages are organized as shown by the solid line in the figure. For example, rare earth magnet powder (1) -c is used as a binder (2) as a flexible system (rubber, thermoplastic elastomer) (2) -a, rigid thermoplastic resin (2) -b, rigid thermosetting resin (2). (2) and (3), such as calendaring / extrusion molding (3) -a, injection molding (3) -b, compression molding (3) -c It is linked with all elements of. However, in cooperation between compression molding (3) -c and rare earth magnet powder (1) -c, the element of binder (2) is, for example, a hard thermosetting resin (2) -c such as epoxy resin. The current situation is limited to relationships.
[0006]
For example, the relationship between the three major element technologies in the production of bonded magnets, that is, the rare earth magnet powder (1) -c, the binder (2), and the molding method (3) and the high performance of the motor are as follows: F. Yamashita, Y. et al. Sasaki, H .; Fukunaga, Isotropic Nd-Fe-B Thin Arc-shaped BondedMagnets for Small DC Motors Prepared by Powder Compacting Press with Metal Ion-Imp. 25, no. 4-2, PP. 683-686 (2001), in the production of a thin arc magnet having a maximum thickness of 0.9 mm, rare earth magnet powder (1) -c / hard thermoplastic resin (2) -b / extrusion molding (3) By changing from cooperation with -a to rare earth magnet powder (1) -c / hard thermosetting resin (2) -c / compression molding (3) -c, permanent magnet with 200mW output The maximum efficiency of field type small DC motor is improved by 8%. This suggests that even if the rare earth magnet powder is exactly the same, an efficient small motor can be provided by recombination of cooperating elements.
[0007]
By the way, the sheet magnet which has been conventionally studied as a magnet of a small motor having a machine output number of 10 W or less, which is the object of the present invention, is used from the viewpoint of cooperation of the three major element technologies in the manufacture of the bond magnet of FIG. In summary, ferrite magnet powder (1) -a or rare earth magnet powder (1) -c / flexible type (rubber, thermoplastic elastomer) (2) -a / calender ring / extrusion molding (3) -a It can be expressed by cooperation. Many ideas have been made under this cooperation.
[0008]
For example, a sheet magnet composed of rare earth magnet powder (1) -c, flexible rubber, and thermoplastic elastomer (2) -a is cut into a strip shape, and is annularly curled on the inner surface of the peripheral wall of the frame. Permanent magnet type motors are known which are fixed and face the salient pole surface of an armature core. As prior art of this magnet and motor, Japanese Patent No. 2766746 discloses (1) Nd-Fe-B type, (Ce, La) -Fe-B type rare earth magnet powder, (2) natural rubber, isoprene rubber. , Butadiene rubber, styrene butadiene rubber, butyl rubber, ethylene propylene rubber, ethylene vinyl rubber, nitrile rubber, acrylic rubber, urethane rubber, (3) chloroprene rubber, chlorosulfonated polyethylene, and chlorinated polyethylene (1) to (3) One or more of the groups are selected, and (1) is 92-96 wt. %, Density 4.9-5.8 Mg / m ^Three Sheet magnet. Japanese Patent No. 2528574 discloses (a) a step of kneading R-Fe-B (R is Nd / Pr) rare earth magnet powder and a resin such as rubber and thermoplastic elastomer, and (b) the kneaded product. A method for producing a sheet magnet is disclosed, comprising: crushing the sheet magnet and then calendering the sheet, and (c) heat treating the sheet magnet at 125 to 180 ° C. for 60 to 180 mun. Yes.
[0009]
However, (1). The density of the sheet magnet is 4.9 to 5.8 Mg / m ^Three Limit of magnetic performance from the above, (2). Flexible thermoplastic elastomers and rubbers and rare earth magnet powders have poor adhesion, and rare earth magnet powders fall off due to the magnetic attraction force of the excited armature core, causing rotational noise and rotation disturbance during motor operation. Issues related to reliability, such as causing, (3). Processes such as rubber vulcanization and reheating of the cut surface were complicated, and there were also problems in reliability such as corrosion and accelerated wear of electric sliding contacts such as brush-commutators due to residual sulfur gas from vulcanization.
[0010]
In JP-A-5-299221, Sm-Fe-N rare earth magnet powder and acid-modified styrene elastomer are calendered (kneading / rolling) and further cut strips are curled. Density 5.6 Mg / m for use in small motors ^Three , Maximum energy product (BH) _max 35 kJ / m ^Three An annular magnet is disclosed. However, magnetically isotropic R-Fe-B (R is Nd / Pr) rare earth magnet powder and hard epoxy resin (BH) _max ~ 80kJ / m ^Three Compared with magnets of this type, the magnetic performance is not as good, and a strong static magnetic field cannot be obtained in the desired gap with the armature core. In addition, Sm-Fe-N magnet powder is made of several μm of Sm. ₂ Fe ₁₇ N _Three Because it is a fine powder consisting of a single magnetic phase, it is generally chemically active, and rare earth-iron-nitrogen magnet powder is exposed to the atmosphere at the cut surface, causing irreversible magnetic flux loss and thermoplastic elastomer based on permanent demagnetization due to oxidative corrosion. There was also a serious problem of partial collapse of the magnet due to a decrease in the adhesion between the magnet powder and the magnet powder, and the magnet powder falling off and scattering.
[0011]
On the other hand, a film magnet having a thickness of 200 μm or less is used for a millimeter-meter size high-performance motor, actuator, magnetic drive element, etc., which is used as a drive source in micro robots, medical treatment, space development and the like. Needless to say, thin-film rare-earth magnets are generally produced by sputtering. For example, Japanese Patent Laid-Open No. 05-21865 discloses a method of forming a thin-film rare earth magnet on a substrate such as a glass substrate, a quartz substrate, and a silicon wafer by a sputtering method. A method for forming a metal layer therebetween is disclosed. In Japanese Patent Laid-Open No. 06-151226, in a method of forming a thin-film rare earth magnet by sputtering, a metal layer having a thickness of about 1 to 40 nm and an R of less than 5 μm having anisotropy in the thickness direction. ₂ Fe ₁₄ A method for forming a thin-film rare-earth magnet in which B (R is a rare-earth element including Y) alloy layers are alternately laminated, Nd in Japanese Patent Laid-Open No. 08-83713 ₂ Fe ₁₄ It has been disclosed that the optimum production conditions in the sputtering method of a rare-earth magnet of a thin film containing B as the main phase are a substrate temperature of 530 to 570 ° C., a deposition rate of 0.1 to 4 μm / hr, and a gas pressure of 0.05 to 4 Pa. ing. Further, Japanese Patent Laid-Open No. 09-162034 discloses Nd on a substrate. ₂ Fe ₁₄ B, SmCo _Five , Sm (Co, Fe, Cu, Zr) ₇ , SmFe ₁₁ Ti, Sm ₂ Fe ₁₇ N ₂ In a film magnet having a multilayer alloy film in which hard magnetic layers made of so-called rare earth magnets and soft magnetic layers such as Fe, Fe—Ni, Fe—Co, Fe—Si, Fe—N, and Fe—B are alternately laminated. The hard magnetic layer having a thickness of 2 to 4 nm per layer on the substrate by sputtering at a substrate temperature of 450 to 800 ° C. and having anisotropy in the thickness direction, and a substrate temperature of 150 to 650 ° C. A thin-film rare earth magnet having a multilayer structure in which the soft magnetic layers having a thickness of 6 to 12 nm per layer and magnetic anisotropy in the thickness direction are alternately laminated by the sputtering method is disclosed. Yes. Also, Japanese Patent Laid-Open No. 09-237714, Japanese Patent Laid-Open No. 11-214219 discloses the thickness of the soft magnetic layer and the hard magnetic layer adjacent to each other in the in-plane direction at a substrate temperature of 300 to 800 ° C. by, for example, sputtering. A thin-film rare earth magnet having a multilayer structure having a thickness of 0.01 to 300 μm strictly controlled at a standard is disclosed.
[0012]
However, in order to produce a thin-film rare earth magnet by the sputtering method, it is necessary to heat the substrate to 450 ° C. or higher, and the film formation rate is limited to 0.1 to 4 μm / hr. In particular, Nd ₂ Fe ₁₄ A thin-film rare earth magnet having B as the main phase is limited to a film thickness of less than 5 μm in order to suppress a decrease in coercive force due to oxidation. In addition, in the thin-film rare earth magnet having a multilayer structure of 0.01 to 300 μm, in which the thickness of the soft magnetic layer and the hard magnetic layer is strictly controlled at the nm level, the magnet production is further complicated and the economical consistency is poor. Become. Japanese Patent Application Laid-Open No. 11-288812 discloses a thin-film R—Fe—B rare earth magnet which is formed by sputtering without heating the substrate, and is heat-treated after film formation. However, this method also has a problem that the film formation rate is 4 μm / hr or less and a problem that the film thickness of the magnet is limited to tens of μm or less.
[0013]
There is a strong demand for downsizing motors and actuators. The key to miniaturization of motors and actuators is to reduce the number of components and simplify assembly. For this reason, the mover of small motors and actuators is composed of rare earth sintered magnets by powder metallurgy, and rare earth bonded magnets in which flake-shaped magnet powders by the melt span method are hardened to a specific shape with resin. It is common to do. From the positional relationship between the magnet and the armature winding, an axial gap type in which the magnet and the armature winding have a gap in the axial direction, and a radial gap type in which the magnet and the armature winding have a gap in the radial direction, Has been proposed. However, for example, in a motor or actuator having a diameter of 5 mm and a height of 1 mm as shown in FIG. 2 or an actuator (in this case, an axial gap type), the rare earth magnet constituting the mover is also 300 μm thick, or It is necessary to configure with a film magnet smaller than that. In the figure, 1 is a film magnet, 2 is a rotating shaft, 3 is an armature winding, and 4 is a bearing.
[0014]
By the way, Nd ₂ Fe ₁₄ Rare earth sintered magnets with B as the main phase generally have a crystal grain size of 6-9 μm, and there is an R-rich phase at the grain boundaries, so the surface magnetic performance from the surface to a depth of several 10 μm during grinding Causes processing deterioration. Further, since the material is brittle and difficult to process, the processing limit in consideration of the yield is estimated to be about 500 μm, making it difficult to cope with the application shown in FIG. Nd by melt span method ₂ Fe ₁₄ Rare earth bonded magnet with B as main phase is Nd of magnet ₂ Fe ₁₄ Although the B crystal grain size is relatively small at 20 to 100 nm, a decrease in magnetic performance due to a decrease in magnet density is inevitable, and the processing limit considering the maintenance of magnetic performance and the yield is still estimated to be about 500 μm.
[0015]
As described above, millimeter-meter-sized motors, actuators, and magnetic drive elements can be directly used as rare earth sintered magnets by conventional powder metallurgy techniques, or bonded magnets in which rare earth magnet powders are hardened with resin. However, the original magnetic performance of rare earth magnets could not be fully utilized as a motor or actuator.
[0016]
Further, in order to produce a thin-film rare earth magnet by the sputtering method, it is generally necessary to heat the substrate to 450 ° C. or higher, and the film formation rate is limited to 0.1 to 4 μm / hr. In particular, Nd ₂ Fe ₁₄ A thin-film rare-earth magnet having B as the main phase has a film thickness limited to less than 5 μm due to a decrease in coercive force due to oxidation during sputtering. In addition, the thin film rare earth magnets with a thickness of 0.01 to 300 μm, in which the thicknesses of the soft magnetic layer and the hard magnetic layer are strictly controlled at the nm level, are particularly complicated and economically consistent. Has the disadvantage of becoming poor. When the motor or actuator is downsized, the electromagnetic force is “L” according to the scaling law. ^Three (L is the physique), for example, when the mover size (magnet) becomes 1/10, the electromagnetic force decreases to 1/1000. Therefore, if a rare earth magnet with a film thickness of less than 5 μm is used as a mover, there is an essential problem that an output corresponding to a load in actual use cannot be obtained.
[0017]
[Problems to be solved by the invention]
As described above, the rare earth magnet powder (1) -c / flexible system (rubber, thermoplastic elastomer) (2) -a / calendar can be summarized from the viewpoint of cooperation among the three major elemental technologies in the bond magnet production shown in FIG. -Conventionally, many devices have been devised under the cooperation of ring or extrusion molding (3) -a. Nevertheless, the magnets produced under this cooperation have many problems and are rarely used for permanent magnet motors. And under this cooperation, ferritic magnet powder (1) -a / flexible system (rubber, thermoplastic elastomer) (2) -a / calendar ring or extrusion molding (3) -a A sheet magnet using the ferrite magnet powder prepared is applied to a small motor. However, this magnet is (BH) _max ~ 12kJ / m at most ^Three Therefore, a strong static magnetic field cannot be obtained in the gap between the armature core and the field. Therefore, it is no exaggeration to say that it is a small motor that is not efficient for recent electrical and electronic equipment.
[0018]
Therefore, it will be described below how the magnets produced by the cooperation are the mainstream for efficient small motors with a machine output of 10 W or less.
[0019]
Japanese Patent Publication No. 6-87634 by the present inventors can be cited as one of typical proposals for an efficient small motor using a rare earth bonded magnet. That is, magnetically isotropic R-Fe-B (R is Nd / Pr) rare earth magnet powder (1) -c and hard epoxy resin (2) in order to create a strong static magnetic field in the air gap facing the armature core. ▼ -c compression molding ▲ 3 ▼ -c outer diameter 25 mm or less, density 5 Mg / m ^Three This is a permanent magnet type motor having a configuration in which the above-mentioned annular rare earth bonded magnet is magnetized in multiple poles. Magnetically anisotropic rare earth magnet powder (1) -c is injection-molded (3) -b with a hard thermoplastic resin (2) -b as a binder, or a hard thermosetting resin (▲ Regardless of the cooperation in compression molding (3) -c) in 2 ▼ -c), the radial anisotropic magnet has a reduced magnetic property in the radial direction because the degree of orientation decreases as the diameter decreases. Therefore, in motors using radial anisotropic magnets, the mechanical output of the motor is inevitably decreased in conjunction with the decrease in the radial magnetic characteristics as the diameter of the annular magnet is reduced. That is, the radial anisotropic magnet has a drawback of becoming an inefficient motor as the size is reduced. However, if the magnetically isotropic rare earth magnet powder is used, the magnetically isotropic Nd—Fe—B rare earth magnet powder is compressed (BH, for example) without depending on the diameter of the annular magnet. ) _max 80 kJ / m ^Three To reach. This value is (BH) for ferrite sheet magnets. _max 12kJ / m ^Three Is approximately 6.7 times. As a result, this type of magnet was effective in increasing the output and current consumption of small motors, and gained recognition as a so-called efficient small motor mainly in the field of electrical and electronic equipment. For example, manufactured in cooperation with ferrite magnet powder (1) -a / flexible system (rubber, thermoplastic elastomer) (2) -a) / calender ring or extrusion (3) -a) Starting torque 1.5 mN of a small motor, which is a 1.55 mm thick and 7.2 mm wide sheet magnet cut into a strip shape, curled and fixed to the inner surface of the peripheral wall of a rotor frame having an inner diameter of 22.5 mm -M is a magnetically isotropic rare earth magnet powder (1) -c and a hard epoxy resin (2) -c) compression molded (3) -c outer diameter 22.5 mm , Thickness 1.10mm, height 9.4mm, density 5.8Mg / m ^Three The starting torque of a permanent magnet type motor using this magnet reaches 13 times 20 mN-m.
[0020]
As described above, typical magnets to be used in the present invention are ferrite magnet powder (1) -a) / flexible system (rubber, thermoplastic elastomer) (2) -a) / calender ring or extrusion (▲ 3 ▼ -b) together with magnets and magnetically isotropic rare earth magnet powder (1) -c) and thermosetting resin such as hard epoxy resin (2) -c Two examples of magnets formed by compression molding (3) -c can be mentioned. And more efficient motors and associated rare earth bonded magnet manufacturing methods mainly for small DC motors that account for 70% of small motors produced using them, and about 3 billion annually. Is the object of the present invention.
[0021]
[Means for Solving the Problems]
As shown in FIG. 1, the present invention provides a rare earth element by introducing a flexible thermosetting resin composition (2) -d in the binder (2), which is one of the three major elements in bond magnet production. Magnet powder (1) -c), compression molding and rolling or stamping (3) -d), a new form of rare earth bonded magnet from sheet to film, and new high The purpose is to provide a performance permanent magnet type motor (4).
In addition, the arrow of the thick solid line in a figure shows the new cooperation of the magnet manufacturing element concerning this invention.
[0022]
For example, a highly filled compound with magnetically anisotropic rare earth magnet powder is used as a green sheet that is highly oriented in an axial magnetic field. Magnetically isotropic rare earth magnet powder (1) -c) and magnet of compression molding (3) -d) together with thermosetting resin (2) -c such as hard epoxy resin ( BH) _max 80 kJ / m ^Three For example, in the radial direction (BH) _max 140kJ / m ^Three A much higher performance annular magnet can be provided without being affected by its diameter. In addition, from the viewpoint of the bonded magnet manufacturing process, it has high productivity, so there is an advantage that it can be applied by selecting the type of rare earth magnet powder. Therefore, from magnetically isotropic rare earth magnet powder (BH) _max 40 kJ / m ^Three It is also possible to produce a magnet with a degree of economic consistency, which is effective in improving the efficiency of an inefficient small motor using a ferrite rubber magnet. Therefore, it is possible to provide a more efficient small motor (4) using a magnet prepared from a new form.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, a rare earth magnet powder (1) -c), compression molding and rolling, and / or stamping process is performed by using a flexible thermosetting resin binder (2) -d as shown by a thick solid arrow in FIG. In combination with (3) -d), various forms of rare earth bonded magnets ranging from sheets to films having high performance and reliability, and a new high performance permanent magnet type motor using the same. The production method of (4) is provided.
[0024]
The present invention compression-molds a compound mainly composed of rare earth magnet powder (1) -c and a soft thermosetting binder (2) -d to thermally cure the binder component, / And the manufacturing method of the rare earth bonded magnet from the sheet to be stamped ((3) -d) to the film is the main point. In other words, as in the past, a novel rare earth which is different from a binder such as a rubber or thermoplastic elastomer (2) -a, and also a molding process such as calendering or extrusion (3) -a). The present invention relates to technology based on the cooperation of bonded magnet fabrication elements. Further, for example, they are wound, fixed, and magnetized to form an efficient small motor (4) for electrical and electronic equipment.
[0025]
Regarding the binder ((2) -d) in FIG. 1, more specifically, <powdered resin component having at least a thermocompression function and a thermosetting functional group is essential as the binder. The compound is to integrate the rare earth magnet powder by the adhesive force of the binder component, and to give a role to prevent mechanical separation of the binder and the rare earth magnet powder before compression molding. As a specific means for that purpose, the binder is at least a solid epoxy oligomer at room temperature, a thermo-compressible polyamide or / and polyamide-imide powder imparted with tack at room temperature, and a powdery latent epoxy to be added as needed. It is preferable to comprise a curing agent.
[0026]
In the present invention, the tackiness and thermocompression bonding property of polyamide or / and polyamideimide powder refers to the addition of a tackifier and the like, and first the rare earth magnet powder and the binder in a compound state before compression molding. , Fix by its adhesive strength. Next, when the green sheet is formed by compressing the compound, the polyamide or / and the polyamideimide are improved by promoting the plastic deformation by thermal softening of the polyamide or / and the polyamideimide and improving the wettability between the joint surfaces. Alternatively, the thermocompression bonding property of the epoxy oligomer is enhanced. In addition, other components such as a plasticizer are appropriately used in the binder component. The plasticizer reduces the overall viscosity of the polyamide or / and polyamideimide containing the adhesive and promotes flexibility and wetting. Specific examples of the plasticizer used include dibenzyltoluenes, p-hydroxybenzoic acid esters, and benzenesulfonamides, which are compounds having relatively good compatibility with polyamides and / or polyamide imines /. In addition, these plasticizers have good compatibility. However, from the viewpoint of compatibility and plasticization efficiency, that is, homogeneous thermocompression bonding, it is particularly preferable to use carboxylic acid adducts of glycidyl compounds having the following structure. desirable.
[0027]
[Chemical 1]

[0028]
In the above formula, R ¹ , R ² Are the same or different and each represents an aliphatic, alicyclic or aromatic hydrocarbon group. However, R ¹ , R ² At least one of them represents an aromatic hydrocarbon group. This compound is characterized by having at least one aromatic group, and is specifically classified into the following three groups. (A) Aromatic carboxylic acid adduct of aliphatic glycidyl ether or alicyclic glycidyl ether, (B) Aliphatic carboxylic acid or alicyclic carboxylic acid adduct of aromatic glycidyl ether, (C) Aromatic glycidyl ether Aromatic carboxylic acid adduct. The compound belonging to each group is, for example, in the presence of a reaction catalyst selected from tertiary amines, imidazoles, metal ester compounds, phosphorus compounds, etc., with respect to each glycidyl ether as a predetermined carboxylic acid. It can be prepared by adding from normal pressure to reduced pressure while stirring at 120 ° C.
[0029]
Further, it is desirable that the rare earth magnet powder is previously coated with a solid epoxy oligomer at room temperature in order to strengthen the binding force with the binder. Moreover, the average film thickness shall be 0.1 micrometer or less. This is important for preventing a decrease in the degree of orientation due to secondary aggregation of anisotropic rare earth magnet powders. Furthermore, as a method of coating the epoxy oligomer on the rare earth magnet powder, first, the epoxy oligomer is dissolved in an organic solvent, then wet mixed with the rare earth magnet powder, and the bulk mixture from which the solvent has been removed is crushed. . In order to increase the crosslinking density of the epoxy oligomer, a novolak type epoxy having an epoxy group in the molecular chain is desirable. Examples of the powdered epoxy curing agent that crosslinks with the epoxy oligomer include one or more selected from the group of dicyandiamide and its derivatives, carboxylic acid dihydrazide, diaminomaleonitrile and its hydrazide. . These are generally high melting point compounds that are hardly soluble in organic solvents, but those having a particle diameter adjusted to several to several tens of μm are preferred. Examples of dicyandiamide derivatives include o-tolylbiguanide, α-2 · 5-dimethylbiguanide, α-ω-diphenylbiguanide, 5-hydroxybutyl-1-biguanide, phenylbiguanide, α-, ω-dimethylbivic. There are anides. Furthermore, examples of the carboxylic acid dihydrazide include succinic acid hydrazide, adipic acid hydrazide, isophthalic acid hydrazide, and p-axylbenzoic acid hydrazide. These curing agents are preferably added to the compound by dry mixing. In order to prevent transfer of the compound to the mold, 0.2 wt. Of one or more selected from higher fatty acids, higher fatty acid amides and higher fatty acid metal soaps having a melting point higher than the set temperature of the mold. . It is desirable to add to a compound of less than% by dry mixing.
[0030]
The content of the compound rare earth magnet powder was 92 wt. % To 97 wt. %, Compression molding pressure is 4 ton / cm ² As described above, the heat treatment of the binder component of the green sheet is set to be equal to or higher than the reaction start temperature of the epoxy oligomer, and in the final rolling, the rolling rate is 2% or more and the winding limit diameter is 8 mm or less, or the rolling rate is 10%. As described above, when the winding limit diameter is 2 mm or less, a rare earth bonded magnet having good consistency with the mechanical strength can be obtained. In order to reduce the cogging torque of an efficient small motor to be used finally, it is left to the design philosophy of the motor to make the green sheet an unequal width or an unequal thickness. By the way. However, in the present invention, a green sheet having a thickness of about 0.5 to 2.0 mm is usually compression-molded. Therefore, it is possible to flexibly apply the molding process such as calendaring or extrusion molding. There is an advantage that can be accommodated.
[0031]
On the other hand, an arc-shaped rare earth bonded magnet from the sheet to the film can be prepared by stamping the strip-shaped green sheet using, for example, an arc-shaped mold and heat-treating it as necessary. The stamping process is generally a method in which a thermoplastic sheet is heated, softened and press-molded, and is also called stampable sheet molding because it is molded by a system similar to a sheet metal press. (Supervised by Shinroku Saito, New Material Molding Dictionary, P775, Material Information Center, Industrial Research Society, 1988). The binder according to the present invention contains a thermosetting epoxy resin as a component, but from the viewpoint of the molding process, the cited stamping process is considered to be the most similar method, and therefore the stamping process was performed.
[0032]
Furthermore, in the present invention, a soft magnetic composite flexible magnet may be produced in which a green sheet containing soft magnetic powder and a green sheet containing rare earth magnet powder are integrally molded, heat-treated and rolled. it can. Such a soft magnetic composite flexible magnet is advantageous in forming an efficient magnetic circuit because the soft magnetic layer is integrated with the magnet without an adhesive layer.
[0033]
Next, as a magnetically isotropic rare earth magnet powder, Nd—Fe—B spherical powder prepared by spinning cup atomization (BH Rabin, BM Ma, “Recent Developments in”). NdFeB Powder “120th Topical Symposium of the Magnetic Society of Japan 23, 2001).
[0034]
Nd-Fe-B based flare prepared by melt spinning (JJ Croat, JF Herbst, RW Lee and FE Pinkerton, J. Appl. Phys. 55, 2078, 1984). -Powdery powder (RW Lee and JJ Croat, US-Patent 4,902, 361.1990), αFe / Nd-Fe-B based flake powder, Fe _Three Examples thereof include B / Nd—Fe—B based flake powder, Sm—Fe—N flake powder, αFe / Sm—Fe—N flake powder, and the like. The ratio of the particle diameter to the thickness of the flake powder is desirably 4 or less.
[0035]
FIG. 3 shows a production concept diagram of the spinning cup atomization (FIG. 3 left) and melt spinning (FIG. 3 right).
[0036]
Next, as magnetically anisotropic rare earth magnet powder, Nd-Fe-B-based powder prepared by hot upsetting (Die-Up-Setting) (for example, M. Doser, V. Panchanathan; Pulverizing) anisotropic rapidly solidified Nd-Fe-B materials for bonded magnet; J. Appl. Phys. 70 (10), 15, 1993). Magnetically anisotropic Nd—Fe—B based powder prepared by HDDR treatment (hydrogen decomposition / recombination), ie, Nd—Fe (Co) —B based alloy Nd ₂ (Fe, Co) ₁₄ Hydrogenation of phase B (Hydrogenation, Nd ₂ [Fe, Co] ₁₄ BHx), phase decomposition at 650-1000 ° C. (Decomposition, NdH ₂ + Fe + Fe ₂ B), HDDR processing (T. Takeshita and R. Nakayama: Proc. Of the 10) for dehydrogenation (Recombination) and recombination (Recombination). ^th RE Magnets and Ther Applications, Kyoto, Vol. 1,551 1989), which is a magnetically anisotropic rare earth magnet powder. Inactive powder such as Zn whose surface has been photodecomposed in advance (eg, K. Macida, K. Noguchi, M. Nashimura, Y. Hamaguchi, G. Adachi, Proc. 9th Int. Workshop on Rare-Earth) Magnets and Ttheir Applications, Sendai, Japan, II, 845 2000, or K. Macida, Y. Hamaguchi, K. Noguchi, G. Adachi, Digests of the25. ^th Annual conference on Magnetcs in Japan, 28aC-6 2001). The coercive force at 20 ° C. after 4 MA / m pulse magnetization of these magnet powders is desirably 1.1 MA / m or more.
[0037]
On the other hand, as magnetically anisotropic rare earth magnet powder, magnetically anisotropic Sm-Fe-N fine powder prepared by RD (oxidation reduction) treatment, the surface of the powder is previously inactivated. The coercive force at 20 ° C. after the 4 MA / m pulse magnetization of the powder is preferably 0.6 MA / m or more.
[0038]
The rare earth magnet powder may be used alone or in the form of a mixture of two or more. However, it is desirable that the average value of coercive force at 20 ° C. after 4 MA / m pulse magnetization of all the mixed rare earth magnet powders is 0.6 MA / m or more.
[0039]
In addition, after final rolling, it was formed from one or more kinds of polymers having a film-forming ability in which a melt-adhesive (hot-melt adhesive) type self-bonding layer was provided on the surface or a mixed with a mixed isocyanate. It is also effective to improve the mountability to a permanent magnet type motor by providing a self-bonding layer.
[0040]
A permanent magnet type DC motor in which a flexible magnet as described above is wound around the inner peripheral surface of a cylindrical frame, and a fixed and multipolar magnetized annular magnet is used as a permanent magnet field. A permanent magnet type motor having a circular gap rotor on the inner peripheral surface of a cylindrical frame. For example, a permanent magnet type motor having a surface magnet type rotor provided with an annular magnet on the outer peripheral surface of a cylindrical frame may be used. Furthermore, they can be used for various permanent magnet type motors depending on the design concept, such as bonding with a mating material with a self-bonding layer. In particular, the maximum energy product (BH) at room temperature after 4 MA / m pulse magnetization _max 140kJ / m ^Three A permanent magnet type motor equipped with a rare earth bonded magnet from the above sheet to a film is manufactured from Nd-Fe-B flake powder prepared by melt spinning-hard thermosetting resin-compression molding As a next-generation type of permanent magnet type motor, it is particularly promising with a small diameter, and the maximum energy product (BH) at room temperature after 4 MA / m pulse magnetization _max 40kJ / m ^Three Permanent magnet type motors equipped with the above flexible magnets are promising as the next generation of permanent magnet type motors using ferrite rubber magnets.
[0041]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.
[0042]
Example 1
1. material
In this example, four types of rare earth magnet powders having different forms were used. That is, magnetically anisotropic Nd—Fe—B powder (Nd prepared by HDDR treatment (hydrogen decomposition / recombination)) _12.3 Dy _0.3 Fe _64.7 Co _12.3 B _6.0 Ga _0.6 Zr _0.1 ) Powder-A, Nd-Fe-B spherical powder (Nd) prepared by spinning cup atomization _13.3 Fe _62.5 B _6.8 Ga _0.3 Zr _0.1 ) Powder-B, and Nd-Fe-B flake powder prepared by melt spinning (Nd ₁₂ Fe ₇₇ Co _Five B ₆ ) Powder-C, RD (redox) Sm ₂ Fe ₁₇ N _Three Fine powder powder-D. The components of the binder system include a novolak type epoxy oligomer that is solid at room temperature, a powdery latent epoxy curing agent having a particle size of 15 μm or less, a polyamide powder that is frozen and ground to 100 μm or less in advance, and a particle size. A lubricant of 10 μm or less was used in this example. The chemical structure of the novolac epoxy oligomer and the powdery latent epoxy curing agent was as follows.
[0043]
[Chemical formula 2]

[0044]
[Chemical 3]

[0045]
The solid epoxy oligomer was adjusted so as not to form a secondary agglomerated granule in order to improve the degree of orientation of powder-A. The adjustment should be adjusted to 0.1 μm or less when the average film is obtained from the density of the oligomer and the average specific surface area of the magnet powder. The strength after curing hardly changed even when the average film thickness was increased to 0.2 μm.
[0046]
2. Preparation of rare earth bonded magnet
The present invention rationally produces rare earth bonded magnets in various forms ranging from sheet to film from one or more of various rare earth magnet powders such as powder-A, -B, -C and -D. In order to provide an efficient small motor. In particular, an annular rare earth bonded magnet from the sheet to the film according to the present invention including anisotropy oriented in an axial magnetic field such as powder-A is used to frame the magnet from the sheet to the film before and after magnetization. Or obtained by wrapping around a mandrel. As a result, the difficulty of lowering the degree of orientation accompanying the small diameter of the radial magnetic field orientation, that is, lowering the magnetic properties is overcome.
[0047]
FIG. 4 (a) shows the preparation of a flexible bonded magnet from polyamide powder containing powder-A, -B, -C, -D and solid epoxy oligomer, and powdery latent epoxy curing agent and adhesive. It is a block diagram which shows the process for doing. FIG. 4B shows compression molding (▲) together with conventional magnetically isotropic rare earth magnet powder (1) -c and thermosetting resin (2) -c such as hard epoxy resin. It is a block diagram which shows the process for preparing the 3 ▼ -d) magnet. FIG. 4B shows an example of F.R. Yamashita, Y. et al. Sasaki, H .; Fukunaga, Isotropic Nd-Fe-B Thin Arc-shaped Bonded Magnets for Small DC Motors Prepared by Powder Compacting Press Ion-Ion-Ion. Magn. Soc. Japan, Vol. 25, no. 4, PP. 683-686 (2001). It is described in. As is apparent from the block diagrams of FIGS. 4A and 4B, the compound of the present invention can be prepared by mixing rare earth magnet powder and a binder component as compared with the conventional method. In addition, the compression molding and curing of the compound are the same, and in the present invention, a rolling and / or stamping process for making the sheet magnet into the final form exists as an essential process.
[0048]
The description of FIG. 4 will be given. (Mixing: Mixing, Compacting press: Powder molding, Curing: Curing, Rolling: Rolling, Stamping: Stamping, Pre-crushing: Pre-grinding, Wet-mixing: Wet mixing, Evaporating: Evaporation, Crushing: Crushing, Classification, Drying -Blending: dry mixing, coating: painting).
[0049]
According to the manufacturing process of the embodiment of the present invention shown in FIG. 5 kg of a predetermined amount of rare earth magnet powder powder-A, B, C, and D is put into a Σ blade mixer heated to 60 ° C., and 50% acetone solution of a solid epoxy oligomer at room temperature while stirring the powder. 50 g was added dropwise. When stirring was continued, a rare earth magnet powder coated with an epoxy oligomer dried in about 5 minutes was obtained. When the surface coating thickness of the rare earth magnet powders powder-A, B, C and D is about 0.1 μm or less, the powder particle size distribution before and after the coating of powder-A, B, C and D changes little. There wasn't. Subsequently, 3 to 7 wt.% With respect to the rare earth magnet powder whose surface was coated with the epoxy oligomer. Polyamide particles containing 20% adhesive, a powdery latent epoxy curing agent, and a lubricant (calcium stearate having a particle diameter of 10 μm or less) were added to obtain a powdery compound. These powdered compounds had powder flowability that could be applied to a powder molding machine with a lubricant.
[0050]
Next, the powdery compound was put into the feeder cup of the powder compression molding machine, and the powdery compound was filled into the mold cavity. However, only the upper and lower punches of the mold and the periphery of the cavity are heated to 70 to 80 ° C. The compound containing magnetically anisotropic rare earth magnet powder filled in the cavity is compressed by the upper and lower punches in an axial magnetic field of 1.4 MA / m, demagnetized, and green compact is used. Obtained. This green sheet had sufficient handling properties.
[0051]
In FIG. 5, (Number of shots: number of moldings, Weight: weight).
[0052]
FIG. 5 shows that Powder-A having a width of 6.1, a length of 71 mm and a thickness of 1.25 mm is 96 wt. FIG. 5 is a characteristic diagram showing the weight (g) of the green sheet with respect to the number of moldings when a green sheet consisting of% is repeatedly molded by a powder molding machine. The green sheet has a weight average of 1.991 g and a standard deviation of 0.007 g when molded 90 times, and a compound capable of industrially forming powder is obtained.
[0053]
Next, the Powder-A was 96 wt. % Sheet was heated at 180 ° C. for 20 minutes to form a hardened sheet. FIG. 6 shows that a magnetically anisotropic Powder-A having a thickness of 0.8 to 2.5 mm is 96 wt. The relationship between the magnetic flux and the thickness of the sheet is shown when the sheet is heat-cured and then the sheet is magnetized with 4 MA / m pulses in the thickness direction. Furthermore, this sheet was rolled with a constant-speed roll heated to 70 mm in diameter and 70 ° C., and the relationship between the thickness after rolling and the magnetic flux was shown. The magnetic flux before rolling observed as shown in the regression equation in the figure decreases as the sheet thickness decreases. The rolled sheet has a large decrease in magnetic flux compared to the sheet thickness before rolling, and is particularly remarkable when the sheet thickness before rolling is 2 mm or more. However, when the sheet thickness before rolling is 1.3 mm or less, the decrease in magnetic flux due to rolling is suppressed as compared with the case where the sheet thickness is 2 mm or more, and it follows the regression formula of the change in magnetic flux with respect to the sheet thickness before rolling. The value comes to be obtained. This is because a sheet containing magnetically anisotropic rare earth magnet powder such as Powder-A is likely to be disturbed by rolling when the thickness is 2 mm or more, but less likely to be disturbed when the thickness is 1.3 mm or less. . Therefore, in a sheet containing magnetically anisotropic rare earth magnet powder such as Powder-A, a sheet of 1.3 mm or less is rolled to form the rare earth bonded magnet according to the present invention from the sheet to the film. Is desirable.
[0054]
In FIG. 6, (○: Before rolling before rolling, ●: Rolling out after rolling, Thickness: Thickness, Flux: Magnetic flux, R ² : Correlation coefficient).
[0055]
In FIG. 7, (○: Before rolling before rolling, ●: Rolling out after rolling, Thickness: thickness, Flux: magnetic flux, R ² : Correlation coefficient).
[0056]
FIG. 7 shows 95 wt. FIG. 5 is a characteristic diagram showing the thickness of a sheet containing magnetically anisotropic rare earth magnet powder in which 10% of% Powder-A is replaced by Powder-D and the change in magnetic flux due to rolling. Powder-D has a small powder particle size of 2 to 3 μm. However, when the rolling rate is small at a sheet of 1.3 mm or less, a tendency of increasing the magnetic flux by rolling is also observed. FIG. 8 shows 95 wt. Powder-D in a 1.17 mm-thick sheet magnet (molding pressure 400 MPa) containing magnetically anisotropic rare earth magnet powder in which 0 to 50% of Powder-A is replaced with Powder-D up to 50% It is a characteristic view which shows the magnet density with respect to the substitution rate. When the powder particle diameter is as small as 2 to 3 μm as in Powder-D, the magnet density decreases when the substitution amount exceeds 10%. Therefore, FIG. 9 shows the relationship between the thickness of the sheet magnet and the magnetic flux when the replacement rate of Powder-D with a small density drop is set to 5, 10%. As is clear from the figure, the magnetic flux from the sheet to the film with the replacement rate of Powder-D being 5% to 10% when the magnet thickness is equal to or less than 1 mm although the magnet density is equal is the Powder- A magnetic flux higher than that of the A-only sheet magnet can be obtained. As is clear from the figure, this tendency becomes more prominent as the film magnet becomes thinner. Therefore, since the average powder particle diameter of Powder-A is as large as 80 μm, when preparing a rare earth bonded magnet from a thin sheet of 1 mm or less to a film, a rare earth magnet with a large powder particle diameter such as Powder-A is prepared. Rather than using powder alone, it is preferable to use rare earth magnet powder with a small powder particle diameter such as Powder-D in a range of 10% or less where the magnet density does not decrease.
[0057]
In FIG. 8, (weight fraction of Powder-D: ratio of Powder-D, Density: density).
[0058]
FIG. 10 is a characteristic diagram showing changes in magnetic flux with respect to the rolling rate of a sheet having a thickness of 1.3 mm or less. However, 96 wt. %include. As shown in the figure, when the rolling rate is approximately 15% or less, the magnetic flux change exceeding 10% does not occur regardless of the shape (flakes, spheres, etc.) of the rare earth magnet powder contained in the sheet. However, if it exceeds 15%, the magnetic flux starts to increase in Powder-C, a flake-shaped rare earth magnet powder by melt spinning, and Powder-B, a spherical rare-earth magnet powder by spinning cup atomization, It starts to increase. However, the magnetically anisotropic rare earth magnet powder Powder-A does not increase the magnetic flux. In magnetically isotropic Powder-B and -C, it can be said that an increase in density accompanying an increase in rolling ratio has caused an increase in magnetic flux.
[0059]
In FIG. 9, (Tickness: thickness, Incending rate of flux: increase rate of magnetic flux).
[0060]
In FIG. 10, (□: Powder-A, ●: Powder-B, x: Powder-C, Rolling rate: rolling rate, Change in flux: change in magnetic flux).
[0061]
FIG. 11A shows that Powder-A is 96 wt. % Is a film magnet having a thickness of 200 μm, and FIG. 11B is an external view showing a state in which the film magnet is wound around a mandrel having a diameter of 0.8 mm. As shown in the figure, the rare earth bonded magnet from the sheet to the film according to the present invention can be easily wound and fixed on a mandrel having a diameter of 1 mm or less. In particular, when a rare earth bonded magnet of the present invention provided with a self-bonding layer having a good film forming ability is wound around a rotating shaft and fixed by baking, a radially anisotropic rare earth bonded magnet having a diameter of about 1 mm as shown in FIG. It is possible to prepare a surface magnet type rotor including As described above, the film magnet according to the present invention is mechanically less than a thin-film rare-earth magnet by sputtering, a thick-film rare-earth sintered magnet produced by grinding, a low-density compression-molded rare-earth bond magnet, or an injection-molded rare-earth bond magnet. It is not fragile, and it can be said that it is excellent as a magnet for mm size motors because it is easy to punch and wrap, and to be bonded.
[0062]
FIG. 12 shows that Powder-A was 97 wt. A strip-shaped green sheet having a width of 4 mm, a length of 15.5 mm and a thickness of 0.9 mm is stamped at a pressure of about 400 MPa using an arc-shaped mold at 80 ° C., and further at 180 ° C. for 15 min. It is an external view of a radial anisotropic arc-shaped magnet having a maximum thickness of 0.9 mm, an inner radius of 3.55 mm, and an outer radius of 3.65 mm that has been heat-cured. The stamping process is generally a method in which a thermoplastic sheet is heated, softened and press-molded, and is also called stampable sheet molding because it is molded by a system similar to a sheet metal press. (Supervised by Shinroku Saito, New Material Molding Dictionary, P775, Material Information Center, Industrial Research Society, 1988). The binder according to the present invention contains a thermosetting epoxy resin as a component, but from the viewpoint of the molding process, the stamping process cited is considered to be the most similar method. did.
[0063]
As described above, the rare earth bonded magnet converted into the final form by rolling or / and stamping from the sheet to the film according to the present invention is magnetically anisotropic rare earth magnet powder and isotropic flake. Can be prepared from one or more of rare-earth magnet powders powder-B, -C, Powder-D ranging from a spherical shape to a spherical shape, and the magnetic properties as a rare earth bonded magnet and the form as a magnet can be diversified. it can.
[0064]
3. durability
The prepared magnets were examined for their magnetic properties and irreversible magnetic flux loss obtained from mechanical properties such as tension and extension, and demagnetization curves. FIG. 13 shows that 96 wt. It is a characteristic view which shows the temperature dependence of the tension | tensile_strength of 1.17-mm thickness sheet magnet containing%, and expansion | extension. However, the solid line in the figure represents tension and the broken line represents elongation. As shown in the figure, regardless of the type of rare earth magnet powder, the tension is high at low temperatures and the elongation increases at high temperatures. However, the tension near room temperature is 96 wt. % Of ferrite magnet powder (▲ 1 ▼ -a) / flexible system (rubber, thermoplastic elastomer) (▲ 2 ▼ -a) / calendar ring or extrusion (▲ 3 ▼ -a) The tension of 50-100 kgf / cm 2 and the elongation of about 2-8%, which is equivalent to the conventional magnet prepared in (1), are provided.
[0065]
In FIG. 13, (Temperature: temperature, Tensile strength: tension, Elongation: elongation).
[0066]
FIGS. 14A and 14B are characteristic diagrams showing changes in tension and elongation when the 1.17 mm thick sheet rare earth bonded magnet according to the present invention is exposed to 120 ° C. for 1000 hrs. As shown in the figure, the tension hardly changes or gradually increases after long-term high temperature exposure. When the tension increases, the elongation decreases correspondingly. Regardless of the form of the rare earth magnet powder, the rare earth bonded magnet from the sheet to the film according to the present invention is at a level that can withstand practical use in terms of mechanical property durability.
[0067]
FIG. 15 is a characteristic diagram showing a change in thickness of a magnet when a 1.17 mm thick sheet-like rare earth bonded magnet rolled at a rolling rate of 6 to 8% according to the present invention is exposed to 120 ° C. and 1000 hrs. As shown in the figure, the magnet dimensions, such as thickness, change little when exposed to high temperatures for long periods of time. Even in the case of a sheet magnet containing a flake-shaped rare earth magnet powder by melt spinning, the dimensional change is less than 1% at most. Therefore, regardless of the form of the rare earth magnet powder, the rare earth bonded magnets from the sheet to the film according to the present invention can be practically used even when mounted on a small and efficient motor in terms of dimensional stability. is there.
[0068]
In FIG. 14, (Exposure time: Standing time, Tensile strength: Tension, Elongation: Elongation, ●: Powder-A, ◯: Powder-B, ◇: Powder-C).
[0069]
In FIG. 15, (Exposure time: Standing time, Tensile strength: Tension, Elongation: Elongation, ●: Powder-A, ◯: Powder-B, ◇: Powder-C).
[0070]
16 shows 97 wt. Of Powder-A having a maximum thickness of 0.90 mm shown in FIG. 12 stamped at a pressure of 400 MPa at 70 to 80 ° C. according to the present invention. It is a characteristic view which shows the thickness change of the magnet when the arc-shaped rare earth bonded magnet containing% is exposed at 120 ° C. for 1000 hrs. As shown in the figure, a thickness change of about 7% is observed up to about 150 hrs due to stress relaxation by stamping. However, by performing a heat treatment at 180 ° C. for 20 minutes after stamping, the dimensional change considered to be due to stress relaxation is eliminated, and the dimensions of the magnet, such as the thickness of high-temperature exposure for a long time, are almost eliminated. Therefore, the rare earth bonded magnet from the sheet to the film according to the present invention is not only rolled, but also has a dimensional stability that can withstand practical use even if it is stamped or mounted on a small and efficient motor. Yes. In particular, heat treatment after stamping is effective in ensuring initial dimensional stability.
[0071]
In FIG. 16, (Exposure time: exposure time, Changes in thickness: thickness change, After stamping: after stamping, Stamping and annealing: stamping and annealing).
[0072]
FIG. 17 is a characteristic diagram showing the initial irreversible magnetic flux loss of a rare earth bonded magnet according to the present invention having a width of 6.1 mm, a length of 25 mm and a thickness of 1.17 mm. The initial irreversible magnetic flux loss depends strongly on the coercivity and the temperature coefficient of the coercivity of the rare earth magnet powder, but Powder-A (coefficient of coercivity 1.1 MA / m, temperature coefficient of coercivity −0.5% / ° C.) Isotropic NdFeB-based HDDR powder), the demagnetization up to about 100 ° C. shows the same magnetic stability as a sheet magnet containing a flake-shaped rare earth magnet powder by melt spinning. In addition, the spherical powder obtained by spinning cup atomization exhibits the same magnetic stability up to a high temperature region of 180 ° C. as that of a sheet magnet containing a flake-shaped rare earth magnet powder obtained by melt spinning. Therefore, regardless of the form of the rare earth magnet powder, the rare earth bonded magnet from the sheet to the film according to the present invention is practically usable even if it is mounted on a small and efficient motor in terms of magnetic stability. is there.
[0073]
In FIG. 17, (Temperature: temperature, Initial irreversible flux loss: initial irreversible magnetic flux loss ,: Powder-A, ○: Powder-B, ◇: Powder-C).
[0074]
It should be noted that the magnet temperature during motor operation when mounted on most electric and electronic devices targeted by the present invention is 100 ° C. or lower. Therefore, the rare earth bonded magnet from the sheet to the film according to the present invention is generally provided with magnetic stability in the operating temperature range of a small DC motor regardless of the powder-A, B, and C. However, in order to ensure such magnetic stability, it is desirable that the rare earth magnet powder has a coercive force of 600 kA / m or more after pulse magnetization of 4 MA / m at room temperature. In the case of a rare earth bonded magnet from anisotropic sheet prepared from powder-A to a film, the temperature coefficient of coercive force is about -0.5% / ° C. In the case of an anisotropic rare earth magnet powder larger than 4% / ° C and correspondingly powder-A, the coercive force after pulse magnetization of 4 MA / m at room temperature is 600 kA / m or more. It is desirable that it is 1.1 MA / m or more. Note that the rare earth bonded magnet from the sheet to the film according to the present invention prepared from an anisotropic rare earth magnet powder such as powder-A is a long-term magnetic flux like an anisotropic hard epoxy resin bonded magnet. Loss may be a problem. However, recently, it has been reported that this difficulty can be overcome by surface treatment of anisotropic rare earth magnet powder such as powder-A. For example, K.K. Macida, K .; Noguchi, M .; Nushimura, Y .; Hamaguchi, G .; Adachi, Proc. 9th Int. Works on Rare-Earth Magnets and Ttheir Applications, Sendai, Japan, (II), 845 (2000). Alternatively, K. Macida, Y .; Hamaguchi, K .; Noguchi, G .; Adachi, Digests of the25 ^th According to citations such as Annual conference on Magnetcs in Japan, 28aC-6 (2001), magnetically anisotropic rare earth magnet powder such as powder-A is used with a hard epoxy bond magnet at a high compression pressure of about 980 MPa. This is a molded magnet. Compared to the cited literature, the present invention can make rare earth bonded magnets prepared from powder-A at a compression pressure of 380 MPa, which is as low as 40% of them, so that destruction of powder-A during compression, Along with this, the new surface that occurs is reduced. Therefore, it is expected that the long-term magnetic flux loss of the rare earth bonded magnet from the sheet prepared from the powder A to the film in the operating temperature range of 100 ° C. or lower is further reduced.
[0075]
4). Magnetic and motor characteristics of magnets
FIG. 18 shows typical demagnetization curves and BH curves of rare earth bonded magnets from sheet to film according to the present invention prepared from powder-A and -B. Ferrite Magnet Powder (1) -a) / Flexible System (Rubber, Thermoplastic Elastomer) (2) -a / Calendar Ring or Extrusion Molding (3) -a) And magnets compression molded (3) -d together with magnetically isotropic rare earth magnet powder powder-C (1) -c and hard epoxy resin (2) -c It is a characteristic view shown in comparison. However, the test pieces are 1.1 mm thick, 7.5 mm wide and 7.5 mm long, respectively. Numbers 1 and 2 in the figure are typical rare earth bonded magnets from sheet A to B according to the present invention prepared from powder-A and B, and 3 and 4 are conventional Nd-Fe-B bonded magnets. And ferrite rubber magnet. All measurements were performed after magnetization under a 4 MA / m pulsed magnetic field. The compared magnets are magnets that are generally applied to small DC motors and small brushless motors.
[0076]
As is apparent from the figure, the characteristic areas of the typical magnets 1 and 2 according to the present invention are clearly different from those of the conventional typical magnet characteristics 3 and 4 in comparison with the motor armature core of the motor. It is understood that the static magnetic field to the air gap is increased. In particular, as shown in FIG. 18, the powder-A according to the present invention is 97 wt. % Containing magnet (density 5.84 Mg / m ^Three ) (BH) _max 140kJ / m ^Three Of magnetically isotropic rare earth magnet powder (1) -c (powder-C) and hard epoxy resin (2) -c) (BH) ) _max 80 kJ / m ^Three 1.75 times higher than Further, the powder-B according to the present invention was 97 wt. % Containing magnet (5.45 Mg / m ^Three ) (BH) _max 40kJ / m ^Three Is 3 times higher than conventional ferrite rubber magnets.
[0077]
As indicated above, the magnet according to the present invention has good winding properties and magnetic properties for forming an annular magnet. Further, it can be converted into a thin arc shape by, for example, stamping. For example, (BH) _max 140kJ / m ^Three Powder-A showing 97 wt. % Magnets can be wound around a mandrel with a diameter of 0.8 mm.
[0078]
FIG. 19 shows the diameter of the annular magnet and the radial direction of the magnet (BH). _max The relationship is shown. In the figure, Comparative Example 2 is a radial anisotropic magnet in which Sm—Co rare earth magnet powder (1) -c is injection molded (3) -c together with a hard thermoplastic resin (2) -b. Yes, the degree of orientation of the rare earth magnet powder decreases with the diameter of the ring magnet, and accordingly (BH) _max Decrease. On the other hand, as in Comparative Example 1, a flake rare earth magnet powder (1) -c (powder-C) by magnetically isotropic melt spinning is compression molded together with a hard epoxy resin ((2) -c). (▲ 3 ▼ -d) (BH) of magnet _max Is 60-80 kJ / m without depending on the diameter of the annular magnet ^Three Is obtained.
[0079]
However, it is difficult to reduce the diameter of a ring magnet having a diameter of 5 mm or less, particularly until the thickness of the ring itself becomes 200 μm and a film shape. On the other hand, as shown in the example of the present invention, in the example of the present invention, a film magnet having a thickness of 200 μm is formed in an annular shape so that a small diameter and a high (BH) _max An annular magnet can be provided. As described above, the present invention is one of typical proposals for an efficient small motor using rare earth bonded magnets, and is opposed to Japanese Patent Publication No. 6-87634, that is, an armature core. Compression molding of magnetically isotropic R-Fe-B (R is Nd / Pr) rare earth magnet powder (1) -c and hard epoxy resin (2) -c to create a strong static magnetic field in the gap 3 ▼ -c outer diameter 25mm or less, density 5Mg / m ^Three It is possible to provide a next-generation high-performance motor of a permanent magnet motor having a configuration in which the above-mentioned annular rare earth bonded magnet is multipolarized.
[0080]
Next, spherical rare earth magnet powder Powder-B by magnetically isotropic spinning cup atomization was added to 94 wt. % Included (BH) _max 40 kJ / m ^Three FIG. 20 shows the characteristics of a DC motor when a sheet magnet having a thickness of 1.17 mm and a width of 6.1 mm is converted into a ring shape to form a permanent magnet field. The motor has an appearance as shown in FIG. 21 and has a diameter of 24 mm and a height of 12.5 mm. As shown (BH) _max 12kJ / m ^Three Compared with the case where a ferrite rubber magnet having a thickness of 1.17 mm and a width of 6.1 mm is used as a field magnet, the current consumption can be reduced by 1/3.
[0081]
In FIG. 20, (Torque: torque, Current: current, Rotating speed: rotational speed, Mechanical output: mechanical output, Efficiency: efficiency, Conventional ferrite: conventional ferrite).
[0082]
In FIG. 22, (Magnified field: Implanted magnetic field, Improvement of flux ratio: Magnetic flux increase rate, Comparison with Powder-B: Comparison with Powder-B, Comparison with conventional Nd-Fe-B: Conventional Nd-Fe-B: Conventional Nd-Fe-B: Comparison).
[0083]
FIG. 22 shows a case where a spherical rare earth magnet powder Powder-B by magnetically isotropic spinning cup atomization is 94 wt. % Included (BH) _max 40 kJ / m ^Three , 1.17mm thick sheet magnet (BH) _max 140kJ / m ^Three Powder-A showing 97 wt. Increasing rate of magnetic flux with respect to the applied magnetic field of a 1.17 mm thick sheet magnet containing 1%, magnetically isotropic R-Fe-B (R is Nd / Pr) rare earth magnet powder (1) -c and hard epoxy Conventional typical (BH) obtained by compression molding of resin (2) -c (3) -c _max 80 kJ / m ^Three , 1.17mm thick plate-like rare earth bonded magnet (BH) _max 140kJ / m ^Three Powder-A showing 97 wt. It is the characteristic figure which shows the increase rate of the magnetic flux with respect to the applied magnetic field of the sheet magnet of thickness 1.17mm. As shown in the figure, when a rare earth bonded magnet from the sheet according to the present invention to the film is magnetized at an applied magnetic field of 1.5 MA / m or more, preferably 2 MA / m or more, the amount is 1.6 times and 1.3 times, respectively. Can be obtained. A radial anisotropic arc magnet having a maximum thickness of 0.9 mm, an inner radius of 3.55 mm, and an outer radius of 3.65 mm, which has been actually stamped as shown in FIG. The induced voltage of the DC motor used as the magnet field is magnetically isotropic R-Fe-B (R is Nd / Pr) rare earth magnet powder (1) -c and hard epoxy resin (2) -c And 1.36 times the induced voltage 0.218 mV / rpm of a DC motor as shown in FIG. 23, in which a conventional typical rare earth bonded magnet obtained by compression molding (3) -c is used as a permanent magnet field. It showed 296 mV / rpm.
[0084]
By the way, when the gap magnetic flux density between the armature core and the field magnet is increased as in the DC motor according to the present invention, generally the cogging torque may be increased. The cogging torque referred to here is a torque pulsation caused by a change in the permeance coefficient Pc as the armature rotates because the armature core teeth and slots exist on the outer peripheral surface of the armature facing the field. It is. As high as the magnet according to the present invention (BH) _max Since the cogging torque is increased in a motor on which this magnet is mounted, it may cause an increase in motor vibration and noise, or a failure in position control accuracy. The cogging torque is left to the design concept of the motor. However, the rare earth bonded magnet from the sheet to the film according to the present invention has a green sheet with an unequal width or an unequal width in advance in order to reduce the cogging torque of the motor to be finally used. By making it thick, it is possible to easily adopt a means for bringing the gap between the armature core and the field closer to a sine wave shape and suppressing the increase in cogging torque. This cannot be rationally handled by conventional sheet magnet molding processes such as calendaring and extrusion molding. However, in the present invention, since the powdered compound is usually compression molded to a green sheet having a thickness of about 0.5 to 2.5 mm, the flexible shape can be dealt with according to the motor design concept. Can be taken.
[0085]
In the powdered compound according to the present invention, it is selected from the group of Fe, Fe—Ni, Fe—Co, Fe—Si, Fe—N, and Fe—B having a saturation magnetization of 1.3 T or more instead of the rare earth magnet powder. The compound of one or more kinds of soft magnetic powders to be prepared is adjusted, and the green sheet is loaded into the mold cavity, and then the powdery compound according to the present invention is filled into the cavity. Compression molding. Alternatively, only a part of the binder component is compressed first, and then, the powdery compound according to the present invention is filled into the cavity and compression molded. As a result, a complex of green sheets having different functions is obtained. When this composite is heat-treated and rolled, a rare-earth bonded magnet ranging from a sheet with a back yoke to a film and a magnet having heat welding properties can be obtained. Further, one or two or more self-bonding layers of a polymer having a film forming ability, for example, the following structure (Chemical Formula 3) mixed with a stabilized isocyanate is formed in advance on the magnet surface. It can also be used for joining to other parts or other members.
[0086]
[Formula 4]

[0087]
【The invention's effect】
As described above, as a result of intensive studies by introducing a new concept, the present invention can provide a method for producing a rare earth bonded magnet from sheet to film with high productivity regardless of the type of rare earth magnet powder. In particular, the rare earth bonded magnet from the sheet to the film of the present invention does not require a molding process exceeding 200 ° C. as in the conventional molding process (calendering, extrusion molding) and the like, and heat such as irreversible magnetic flux loss. The high magnetic performance inherent in the rare earth magnet powder having stability can be reflected in the motor performance. Therefore, it is possible to provide an efficient small motor with high competitiveness over a conventional small motor equipped with a ferrite magnet or a magnetically isotropic Nd—Fe—B rare earth bonded magnet. Therefore, it is expected not only to contribute to electrical and electronic equipment but also to reduce power consumption and save resources by widespread use.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing the cooperation of three major element technologies in bond magnet production, namely, magnet powder, binder system, and molding method.
FIG. 2 is a cross-sectional configuration diagram of a small motor
[Fig. 3] Manufacturing concept of spinning cup atomization (left) and melt spinning (right)
FIG. 4 is a process diagram for preparing a magnet.
FIG. 5 is a characteristic diagram showing powder moldability by weight change of a green sheet.
FIG. 6 is a characteristic diagram showing the relationship between the thickness of the magnet from the sheet to the film and the magnetic flux.
FIG. 7 is a characteristic diagram showing the relationship between magnetic thickness and magnetic flux from a sheet mixed with different rare earth magnet powders to a film.
FIG. 8 is a characteristic diagram showing the relationship between the mixing ratio and density of different powders.
FIG. 9 is a characteristic diagram showing the relationship between thickness and magnetic flux increase rate.
FIG. 10 is a characteristic diagram showing a rolling rate and a change in magnetic flux.
FIG. 11 is an external view of a film magnet and a small-diameter magnet rotor.
FIG. 12: Appearance of thin arc magnet after sheet stamping
FIG. 13 is a characteristic diagram showing the temperature dependence of tension and elongation.
FIG. 14 is a characteristic diagram showing changes in tension and elongation during long-term high temperature exposure.
FIG. 15 is a characteristic diagram showing the dimensional change of a sheet magnet after long-term high-temperature exposure.
FIG. 16 is a characteristic diagram showing a dimensional change of a circular arc magnet after long-term high-temperature exposure.
FIG. 17 is a characteristic diagram showing initial irreversible magnetic flux loss.
FIG. 18 is a characteristic diagram showing a demagnetization curve.
FIG. 19 is a characteristic diagram showing the relationship between the diameter of an annular magnet and (BH) max.
FIG. 20 is a characteristic diagram of a DC motor.
FIG. 21 is an external view of a DC motor using a magnet wound in a ring shape as a magnetic field.
FIG. 22 is a characteristic diagram showing an increase rate of magnetic flux with respect to the applied magnetic field.
FIG. 23 is an external view of a DC motor using an arc magnet as a field.
[Explanation of symbols]
1 Film magnet
2 Rotating shaft
3 Electron winding
4 Bearing

Claims (46)

Rare earths from sheet to film by rolling compacted powdered compound mainly composed of rare earth magnet powder and thermosetting resin composition, and rolling the obtained green sheet or sheet magnet thermosetting binder component In a bonded magnet, a rare earth bonded magnet from a sheet to a film in which a green sheet or a thickness of the magnet before rolling is 1.3 mm or less and a rolling rate is 15% or less . 2. A rare earth bonded magnet extending from a sheet to a film according to claim 1, wherein the green sheet containing magnetically anisotropic rare earth magnet powder or the rolled thickness of the magnet is 0.2 mm or less . Compress powder molding compound consisting mainly of rare earth magnet powder and thermosetting resin composition, roll the resulting green sheet, and then heat cure the binder component and re-roll A rare earth bonded magnet from the sheet according to claim 1 to the film. 3. The rare earth bond from sheet to film according to claim 1 or 2, wherein the compound is composed of a binder that physically integrates the rare earth magnet powder and other binder components by one or more kinds of adhesives. magnet. Thermosetting resin composition comprising a binder comprising at least a solid epoxy oligomer at room temperature and a thermocompression-bonding polyamide or / and polyamide-imide powder which is tacky at room temperature, and a powdery latent epoxy to be added as necessary The rare earth bonded magnet from a sheet to a film according to claim 1 or 2, comprising a curing agent and a lubricant. The rare earth bonded magnet from the sheet to the film according to claim 1 or 2, wherein the rare earth magnet powder is surface-coated with a solid epoxy oligomer in advance at room temperature. The rare earth bonded magnet from a sheet to a film according to claim 6 , wherein the average film thickness of the epoxy oligomer solid at room temperature is 0.1 µm or less. Claims at room temperature to dissolve the solid epoxy oligomer in an organic solvent rare earth magnet powder and were wet-mixed, the solvent was crushed the massive mixture was removed to coat the solid epoxy oligomer at room temperature in advance rare earth magnet powder surface A rare earth bonded magnet extending from the sheet according to claim 5 or 6 to a film. The rare earth bonded magnet from a sheet to a film according to claim 8 , wherein the epoxy oligomer that is solid at room temperature is a novolak type epoxy having an epoxy group in the molecular chain. The rare earth bonded magnet from a sheet to a film according to claim 5 , wherein a carboxylic acid adduct of a glycidyl compound is used as a plasticizer for polyamide or / and polyamideimide powder. The rare earth bonded magnet from a sheet to a film according to claim 5, wherein the powdery latent epoxy curing agent is a dihydrazide compound. As an additive to be added as necessary, 0.2 wt.% Of one or more selected from higher fatty acids, higher fatty acid amides and higher fatty acid metal soaps having a higher melting point than the mold. % Rare earth bonded magnet from the sheet to the film according to claim 5 . The rare earth bonded magnet from the sheet to the film according to claim 1 or 2 , wherein the compression molding pressure of the compound is 390 MPa or more. 3. A rare earth material from a sheet to a film according to claim 1 or 2 , wherein a powdery compound containing magnetically anisotropic rare earth magnet powder is filled in a plurality of nonmagnetic molds and simultaneously compression molded in an axial magnetic field. Bond magnet. 6. The rare earth bonded magnet from the sheet to the film according to claim 5 , wherein the heat treatment of the binder component of the green sheet is not less than the reaction start temperature of the epoxy oligomer. Magnetically 1.5mm green sheet or the thickness before rolling of the magnet containing rare earth magnet powder of anisotropic below, the rolling reduction in the film from the sheet according to claim 1 or claim 2 wherein the 15% or less Rare earth bonded magnets. The sheet according to claim 1 or 2, wherein a green sheet containing magnetically anisotropic rare earth magnet powder or a rolled film of the magnet having a thickness of 0.2 mm or less and a rolling rate of 15% or less. Rare earth bonded magnets ranging from film to film. Green sheet and rare earth containing one or more soft magnetic powders selected from the group consisting of Fe, Fe—Ni, Fe—Co, Fe—Si, Fe—N, and Fe—B having a saturation magnetization of 1.3 T or more 3. A rare earth bonded magnet from a sheet to a film according to claim 1 or 2, wherein a green sheet containing magnet powder is integrally formed, heat treated and rolled. The rare earth bonded magnet from the sheet to the film according to claim 1 or 2 , wherein the rare earth magnet powder comprises a magnetically isotropic Nd-Fe-B spherical powder prepared by a swinging cup atomization. The rare earth bonded magnet from the sheet to the film according to claim 1 or 2, wherein the rare earth magnet powder comprises a magnetically isotropic Nd-Fe-B flaky powder prepared by melt spinning. 3. The rare earth bonded magnet from sheet to film according to claim 1, wherein the rare earth magnet powder comprises a magnetically isotropic [alpha] Fe / Nd-Fe-B flaky powder prepared by melt spinning. Rare-earth bonded magnet with a rare earth magnet powder reaches the sheet according to claim 1 or claim 2 wherein comprises a magnetically isotropic _{Fe 3 B / Nd-Fe-} B -based flake powder prepared by the melt-spinning the film. The rare earth bonded magnet from the sheet to the film according to claim 1 or 2, wherein the rare earth magnet powder comprises a magnetically isotropic Sm-Fe-N flaky powder prepared by melt spinning. The rare earth bonded magnet from the sheet to the film according to claim 1 or 2, wherein the rare earth magnet powder comprises a magnetically isotropic αFe / Sm-Fe-N flaky powder prepared by melt spinning. The rare earth bonded magnet from the sheet to the film according to any one of claims 20 to 24 , wherein a ratio of a particle diameter to a thickness of the flaky powder is 4 or less. 3. The sheet to the film according to claim 1 or 2, wherein the rare earth magnet powder includes a magnetically anisotropic Nd-Fe-B-based powder prepared by hot upsetting (Die-Up-Setting). Rare earth bonded magnet. 3. The rare earth bonded magnet from sheet to film according to claim 1 , wherein the rare earth magnet powder comprises magnetically anisotropic Nd-Fe-B based powder prepared by HDDR processing (hydrogen decomposition / recombination). . 28. From the sheet to the film according to claim 27, wherein the surface of the magnetically anisotropic Nd-Fe-B-based powder prepared by the HDDR process (hydrogen decomposition / recombination) is deactivated in advance. Rare earth bonded magnet. 3. The sheet to film according to claim 1 or 2, wherein the surface of the magnetically anisotropic Sm-Fe-N fine powder prepared by RD (oxidation reduction) treatment of the rare earth magnet powder is previously inactivated. Rare earth bonded magnets. A magnetically anisotropic magnetic powder prepared by a magnetically anisotropic Nd-Fe-B-based powder according to claims 26 to 28 and an RD (oxidation reduction) treatment according to claim 29, wherein the rare earth magnet powder is prepared. The rare earth bonded magnet from a sheet to a film according to any one of claims 1 to 3, wherein the rare earth bonded magnet is a mixture of less than 10% of Sm-Fe-N fine powder. The rare earth bonded magnet extending from the sheet to the film according to claim 30 , wherein the rare earth bonded magnet has a thickness of 1 mm or less. The rare earth bonded magnet from the sheet to the film according to any one of claims 19 to 24 , wherein the coercive force at 20 ° C after 4 MA / m pulse magnetization of the rare earth magnet powder is 0.6 MA / m or more. The coercive force at 20 ° C after 4 MA / m pulse magnetization of anisotropic Nd-Fe-B-based powder is 1.1 MA / m or more. From the sheet according to any one of claims 26 to 30. Rare earth bonded magnet leading to film. The rare earth bonded magnet from the sheet to the film according to claim 1 or 2 , wherein a self-bonding layer is provided on the surface after rolling . 35. The rare-earth bonded magnet extending from a sheet to a film according to claim 34, wherein the self-bonding layer is a melt-bonding (hot-melt bonding) type. 35. The rare earth bonded magnet from a sheet to a film according to claim 34, wherein the self-bonding layer is one or more kinds of polymers having a film-forming ability mixed with a stabilized isocyanate. A permanent magnet type motor in which a rare earth bonded magnet from a sheet to a film according to claim 1 or 2 is wound around an inner peripheral surface of a cylindrical frame, and a fixed and multipolar magnetized annular magnet is used as a permanent magnet field. A rare earth bonded magnet extending from the sheet to the film according to claim 1 or 2 is wound around the inner peripheral surface of the cylindrical frame, and a permanent magnet is formed as a radial gap rotor having a fixed and multipolar magnetized annular magnet. Magnet type motor. A permanent magnet motor in which a rare earth bonded magnet extending from a sheet to a film according to claim 1 or 2 is wound around an outer peripheral surface of a cylinder and a surface magnet type rotor is formed by a fixed and multipolar magnetized annular magnet. A permanent magnet type motor having a surface magnet type rotor in which a rare earth bonded magnet extending from a sheet to a film according to claim 1 or 2 formed into an arc shape by stamping is fixed to a rotor core. 3. A permanent magnet type motor having a permanent magnet field in which a rare earth bonded magnet extending from a sheet to a film according to claim 1 is fixed to a frame frame by arcuate stamping . An axial gap type permanent magnet motor in which a rare earth bonded magnet from the sheet to the film according to claim 1 or 2 subjected to stamping is magnetized. The permanent magnet type motor according to any one of claims 37 to 41 , wherein the permanent material motor is joined to a counterpart material by a self-bonding layer of a rare-earth bonded magnet extending from the sheet to the film. The permanent magnet type motor according to any one of claims 37 to 39 , wherein both ends of the rare earth bonded magnet from the sheet wound in an annular shape to the film are joined by self-bonding layers to form a ring magnet. A permanent magnet type motor equipped with a rare earth bonded magnet from a sheet to a film according to claim 1 having a maximum energy product (BH) max at room temperature after 4 MA / m pulse magnetization of 40 kJ / m ³ or more. A permanent magnet type motor equipped with a rare earth bonded magnet extending from a sheet to a film according to claim 1, wherein a maximum energy product (BH) max at room temperature after 4 MA / m pulse magnetization is 140 kJ / m ³ or more.

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