JP2005020991A - Rotor and manufacturing method therefor - Google Patents

Rotor and manufacturing method therefor Download PDF

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JP2005020991A
JP2005020991A JP2004112150A JP2004112150A JP2005020991A JP 2005020991 A JP2005020991 A JP 2005020991A JP 2004112150 A JP2004112150 A JP 2004112150A JP 2004112150 A JP2004112150 A JP 2004112150A JP 2005020991 A JP2005020991 A JP 2005020991A
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rotor
soft magnetic
magnet
powder
bonded magnet
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Masahiro Masuzawa
正宏 増澤
Shigeo Tanigawa
茂穂 谷川
Masahiro Mita
正裕 三田
Keiko Kikuchi
慶子 菊地
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Proterial Ltd
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Hitachi Metals Ltd
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Priority to JP2004112150A priority Critical patent/JP2005020991A/en
Priority to CN201010116549A priority patent/CN101777809A/en
Priority to PCT/JP2004/018221 priority patent/WO2005101614A1/en
Priority to EP04821898A priority patent/EP1734637A4/en
Priority to CN2004800057377A priority patent/CN1757148B/en
Priority to US10/549,043 priority patent/US7981359B2/en
Publication of JP2005020991A publication Critical patent/JP2005020991A/en
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent-magnet embedded rotor and a manufacturing method therefor, wherein an unwanted air gap between permanent magnets and soft magnetic material can be reduced, the degrees of freedom in the shape of permanent magnets can be enhanced and the magnetic force from the permanent magnets can be used effectively, and high magnetic characteristics can be obtained; and in more particular, there is no cracks due to spring back, the strength of contact bonding between a bonded magnet portion and a soft magnetic portion is enhanced, and safety is enhanced. <P>SOLUTION: The permanent magnet-embedded rotor comprises the bonded magnet portion, composed mainly of binding material and magnet powder, and the soft magnetic portion composed mainly of a binding material and soft magnetic powder. The rotor is formed by using a compression molding means and, both the faces of the magnetic poles of the bonded magnet portion are embedded in the soft magnetic portion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、永久磁石を使用したモータ、発電機などの高効率化を図ることを目的とした、ヨーク一体型の永久磁石埋設型回転子に関するものである。   The present invention relates to a yoke-integrated permanent magnet embedded rotor for the purpose of improving the efficiency of motors, generators and the like using permanent magnets.

従来、永久磁石式モータは様々な構成が考案されてきた。すなわち、永久磁石が回転子外形部に配置されたいわゆる表面磁石型モータ(SPM)、永久磁石が回転子内部に配置されている磁石埋設設型モータ(IPM)などである。前者は図15にその要部断面図の例を示すように、回転子表面に設置された永久磁石31がヨーク32および固定子間のエアギャップ14に直接接している形式である。17は固定子コイルである。この磁気回路形式を一般に表面磁石型磁気回路と呼ぶ。図15の表面磁石型磁気回路の場合、永久磁石31の任意の永久磁石31aのN極から出た磁束A1は、矢印で示すようにエアギャップ14を貫通し、固定子ヨーク13a部分に達する。次いで、この磁束A1は固定子ヨーク13bおよび13c部分を経由して再びエアギャップ14を貫通し、さらに永久磁石31bおよび回転子ヨーク32を経由して永久磁石31aのS極へ戻る閉ループを形成する。一方、後者は磁石埋設型磁気回路もしくは内部磁石型磁気回路と呼ばれるもので、図16にその要部断面図の例を示す。図16において、永久磁石31はヨーク32内に埋設配置されており、永久磁石31のN磁極側から出た磁束A4は矢印で示すように回転子ヨーク32を経由して固定子13と回転子間のエアギャップ14を貫通する。次いで、この磁束A4は固定子ヨーク13a、13b、13c部分を順次経由して再びエアギャップ14を通過後、回転子ヨーク32を経由して永久磁石31のS磁極に戻る閉ループを形成する。   Conventionally, various configurations of permanent magnet motors have been devised. That is, a so-called surface magnet type motor (SPM) in which a permanent magnet is arranged in the outer shape of the rotor, a magnet embedded type motor (IPM) in which a permanent magnet is arranged in the rotor, and the like. The former is a form in which the permanent magnet 31 installed on the rotor surface is in direct contact with the air gap 14 between the yoke 32 and the stator, as shown in FIG. Reference numeral 17 denotes a stator coil. This magnetic circuit format is generally called a surface magnet type magnetic circuit. In the case of the surface magnet type magnetic circuit of FIG. 15, the magnetic flux A1 emitted from the N pole of an arbitrary permanent magnet 31a of the permanent magnet 31 passes through the air gap 14 and reaches the stator yoke 13a portion as shown by an arrow. Next, the magnetic flux A1 passes through the air gap 14 again via the stator yokes 13b and 13c, and forms a closed loop that returns to the S pole of the permanent magnet 31a via the permanent magnet 31b and the rotor yoke 32. . On the other hand, the latter is called a magnet-embedded magnetic circuit or an internal magnet-type magnetic circuit, and FIG. In FIG. 16, the permanent magnet 31 is embedded in the yoke 32, and the magnetic flux A4 emitted from the N magnetic pole side of the permanent magnet 31 passes through the rotor yoke 32 and the stator 13 and the rotor as indicated by the arrows. It passes through the air gap 14 therebetween. Next, the magnetic flux A4 forms a closed loop that passes the stator yokes 13a, 13b, and 13c sequentially, passes through the air gap 14 again, and then returns to the S magnetic pole of the permanent magnet 31 via the rotor yoke 32.

また、図16のA5に示すようなリラクタンス効果を狙う、磁石回転子の軟磁性部分の突極性を利用したリラクタンスモータも多数考案されている(堺、他:「永久磁石式リラクタンス電動機の基礎特性」、平成10年電気学会全国大会、講演番号1002参照)。これを固定子側の分類から考えるとスイッチドリラクタンスモータとシンクロナスリラクタンスモータとに大別される。スイッチドリラクタンスモータは集中巻きの巻線を持っているのが一般的であり、歯車形状の回転子が集中巻きに施されている固定子の歯に磁気吸引力で吸引され回転を行うものである。これに対し、シンクロナスリラクタンスモータは分布巻きの巻線を持っているものが一般的であり、回転子もスイッチドリラクタンスモータの様な歯車形状ではなく、回転子内部に単数あるいは複数の磁気障壁を設け、磁束の通りやすいd軸と磁束の通り難いq軸とを設け、両軸のインダクタンスの違いによりリラクタンストルクを発生する原理となっている。   A number of reluctance motors using the saliency of the soft magnetic part of the magnet rotor aiming at the reluctance effect as shown in A5 of FIG. "See the 1998 Annual Conference of the Institute of Electrical Engineers of Japan, lecture number 1002). Considering this from the classification on the stator side, it is broadly divided into switched reluctance motors and synchronous reluctance motors. A switched reluctance motor generally has concentrated windings, and a gear-shaped rotor is rotated by being attracted by magnetic attraction to the teeth of a stator applied to the concentrated winding. is there. On the other hand, synchronous reluctance motors generally have distributed windings, and the rotor is not geared like a switched reluctance motor, and has one or more magnetic barriers inside the rotor. The d-axis that easily passes the magnetic flux and the q-axis that hardly passes the magnetic flux are provided, and the principle is that reluctance torque is generated by the difference in inductance between the two axes.

永久磁石と、珪素鋼鈑に代表される軟磁性材料とを比較すると、永久磁石の比透磁率は軟磁性材料の比透磁率に比べ大幅に小さいことは周知の事実である。この永久磁石と軟磁性材料との比透磁率の違いを利用して永久磁石式モータとリラクタンスモータとの特性の両方の特性を有するモータを実現できる。また、IPMにおいても永久磁石を磁気障壁にみたてることにより、リラクタンストルクを発生せしめ、永久磁石モータとリラクタンスモータの両方の特性を有するモータを実現することができる。特に磁石埋設型を基本としたモータは、永久磁石が発生する磁束を有効利用し低速回転時の効率を向上させ、副産物としてのリラクタンストルクを利用することにより高速回転領域までの回転能力を確保することができる。   It is a well-known fact that when a permanent magnet is compared with a soft magnetic material typified by a silicon steel plate, the relative permeability of the permanent magnet is much smaller than that of the soft magnetic material. A motor having both characteristics of a permanent magnet motor and a reluctance motor can be realized by utilizing the difference in relative magnetic permeability between the permanent magnet and the soft magnetic material. Further, in the IPM, by recognizing the permanent magnet as a magnetic barrier, reluctance torque is generated, and a motor having both the characteristics of a permanent magnet motor and a reluctance motor can be realized. In particular, a motor based on a magnet-embedded type effectively utilizes the magnetic flux generated by a permanent magnet to improve the efficiency during low-speed rotation, and secures the rotational capability up to the high-speed rotation region by utilizing reluctance torque as a by-product. be able to.

一方、シンクロナスリラクタンスモータを基本とした磁石埋設型モータは、Reluctance Permanent Magnet Motor(RPM)とも称される事もあり、リラクタンストルクを主に用い、永久磁石の磁束をd軸とq軸の固定子から見たインダクタンスの差をより大きくすること及び永久磁石が発生する磁束による多少のトルクを利用することをいわば補助的に用いている。(以上、(1)W.L.Soong, T.J.E.Miller:“Practical Field-Weakening Performance of the Five Classes of Brushless Synchronous AC Motor Drive”,Proceedings of European Power Electronics Conference(1993)、(2)W.L.Soong, D.A.Stanton, T.J.E.Miller:“Design of a New Axially-Laminated Permanent Magnet Motor”Proceedings of IEEE Industry Applications Society Annual Meeting(1993)参照)
この様に、近年永久磁石の特性が大幅に向上したことにより永久磁石式モータとリラクタンスモータとはその中間の特性を持つモータを任意に作り出せる状況にあり、中でも磁石埋設型方式が期待されている。
On the other hand, a magnet-embedded motor based on a synchronous reluctance motor is sometimes referred to as Reluctance Permanent Magnet Motor (RPM), which mainly uses reluctance torque and fixes the magnetic flux of a permanent magnet between d-axis and q-axis. To increase the difference in inductance seen from the child and to use some torque due to the magnetic flux generated by the permanent magnet is used in an auxiliary manner. (Above, (1) WLSoong, TJEMiller: “Practical Field-Weakening Performance of the Five Classes of Brushless Synchronous AC Motor Drive”, Proceedings of European Power Electronics Conference (1993), (2) WLSoong, DAStanton, TJEMiller: “Design of a New Axially-Laminated Permanent Magnet Motor ”Proceedings of IEEE Industry Applications Society Annual Meeting (1993))
In this way, the permanent magnet motor and the reluctance motor are in a situation where the permanent magnet motor and the reluctance motor can be created arbitrarily as the characteristics of the permanent magnet have been greatly improved in recent years. .

以上のように永久磁石埋設型モータは、様々な特性を実現しており、高精度制御特性を満足しながら、今後さらに要求が高くなるであろう高効率、あるいは用途に応じた最適モータ特性等の実現可能性を秘める優れたモータであると言える。
しかし一方、現在広く使用されているモータでは、珪素鋼鈑等で作成した磁石挿入用穴の空いた薄板を積層する必要があり、個々の部材が細くなり高速回転の回転子には不向きである。また、別に用意した永久磁石を上記穴に挿入・接着するため、加工公差を吸収する必要があり、永久磁石と軟磁性材との間にはクリアランスが必要となる。このクリアランスは、磁気回路の観点からは不要なエアギャップであり、モータの効率低下をもたらす。さらに、クリアランスは接着位置精度を悪くするので、磁石の極ピッチのバラツキを増加させる原因ともなり、コギングトルクと呼ばれるモータにとって不要なノイズの急増をもたらす。
As described above, the permanent magnet embedded motor realizes various characteristics, satisfying high-precision control characteristics, high efficiency that will become more demanding in the future, or optimal motor characteristics according to the application, etc. It can be said that it is an excellent motor that has the feasibility of.
However, on the other hand, in motors that are widely used at present, it is necessary to laminate thin plates with holes for magnet insertion made of silicon steel, etc., and each member becomes thin and is not suitable for a high-speed rotating rotor. . In addition, since a separately prepared permanent magnet is inserted and bonded into the hole, it is necessary to absorb processing tolerances, and a clearance is required between the permanent magnet and the soft magnetic material. This clearance is an unnecessary air gap from the viewpoint of the magnetic circuit, and reduces the efficiency of the motor. Further, since the clearance deteriorates the bonding position accuracy, it causes a variation in the pole pitch of the magnet, and causes a sudden increase in noise unnecessary for the motor called cogging torque.

加えて、永久磁石の形状を単純にして、永久磁石自体及び珪素鋼鈑の加工を簡単にして製造コストの上昇を避ける必要がある。形状への制約としては例えば、磁石にしろ珪素鋼鈑などの軟磁性材料にしろ、極薄部分を形状精度良く安定して設けることは不可能である。一方、リラクタンストルクの有効活用などの観点から、変形磁石の要求は今後ますます増大する。このような問題点を解決する一つの手段として特許文献1では、永久磁石と軟磁性材料とを一体で成形する製造方法が開示されている。しかしながら、このものでは表面磁石型モータ(SPM)にしか適用できず、上記したように優れた可能性を持つ磁石埋設型モータの製造上の問題点を解決するものではなかった。   In addition, it is necessary to simplify the shape of the permanent magnet, simplify the processing of the permanent magnet itself and the silicon steel plate, and avoid an increase in manufacturing cost. As a restriction on the shape, for example, a magnet or a soft magnetic material such as a silicon steel plate cannot stably provide an extremely thin portion with high shape accuracy. On the other hand, from the viewpoint of effective use of reluctance torque, the demand for deformed magnets will increase in the future. As one means for solving such problems, Patent Document 1 discloses a manufacturing method in which a permanent magnet and a soft magnetic material are integrally formed. However, this method can be applied only to a surface magnet type motor (SPM), and does not solve the problems in manufacturing a magnet buried type motor having an excellent possibility as described above.

また磁石埋設型モータ回転子では、複数の永久磁石の間には衝突防止用、補強用の軟磁性材料の橋渡し部分が必要となり、永久磁石からの磁束がこの部分で短絡し、漏れ磁束を生じ、永久磁石の磁束量を無駄なく有効利用する妨げとなる、という不具合点も生じている。このような問題点を解決する一つの手段として特許文献2では、強磁性部分と非磁性部分とが共存した部材によりヨークを構成し、橋渡し部分には非磁性部分を形成することが開示されている。しかしながら、このものでは上記したような加工上また製造上の問題点を解決するものではなかった。   Also, in a magnet-embedded motor rotor, a bridging portion of a soft magnetic material for collision prevention and reinforcement is required between a plurality of permanent magnets, and the magnetic flux from the permanent magnet is short-circuited at this portion, resulting in leakage flux. Further, there is a problem that the magnetic flux amount of the permanent magnet is hindered from being effectively used without waste. As one means for solving such problems, Patent Document 2 discloses that a yoke is constituted by a member in which a ferromagnetic portion and a nonmagnetic portion coexist, and a nonmagnetic portion is formed in a bridging portion. Yes. However, this does not solve the processing and manufacturing problems as described above.

さらに、このような磁石粉末と軟磁性粉末を一体に圧縮成形するような圧縮成形体を製造すると、圧縮成形の金型から成形体を取り出す際の両粉末のスプリングバックにより割れが発生するという問題がある。また、割れが発生しなくても強磁性部分と非磁性部分との間の圧着強度が弱いと、回転子をモータに組み込んだ後に回転中の遠心力で割れる恐れもある。   Furthermore, when a compression molded body is produced in which such magnet powder and soft magnetic powder are integrally compression molded, there is a problem that cracking occurs due to springback of both powders when the molded body is taken out from a compression mold. There is. Even if no cracking occurs, if the pressure bonding strength between the ferromagnetic part and the non-magnetic part is weak, the rotor may be broken by the rotating centrifugal force after being incorporated into the motor.

また、特許文献3等に記載されているように、珪素鋼鈑等で作成した磁石挿入用穴の空いた薄板を積層し、この磁石挿入用穴にボンド磁石用コンパウンドを射出し、焼結磁石の替わりにボンド磁石をクリアランス無く回転子の内部に設ける手法もある。しかしながらこの方法では、コンパウンドの流動性を良くするために樹脂量を多くし、磁粉や鉄粉の混合量を低下せざるを得ないため、磁気特性が低下してしまうという問題がある。また、モータが大型になるほど大型化した永久磁石に流れる電流が増加し、渦電流損も増加する。そこで渦電流損を低減させるために、非特許文献1などでは、磁石1極を細分割し表面塗装膜や接着層で電気の流れを断ち切る必要があることが記載されている。しかし工程的に結構な手間がかかり、製造コストを増大させる原因となっている。
特開平7−169633号公報((0040)〜(0043)、図1) 特開平8−331784号公報((0021)〜(0023)、図1) 特開2002−134311号公報((0087)〜(0090)) 三田:「表面磁石型モータのうず電流解析」、’98モータ技術シンポジウム(1998)
Moreover, as described in Patent Document 3 and the like, a thin plate with a hole for inserting a magnet made of a silicon steel plate or the like is laminated, and a compound for a bonded magnet is injected into the hole for inserting a magnet, and a sintered magnet Alternatively, there is a method of providing a bonded magnet inside the rotor without clearance. However, this method has a problem that the magnetic properties are deteriorated because the amount of resin is increased in order to improve the fluidity of the compound and the mixing amount of magnetic powder and iron powder must be decreased. Further, as the motor becomes larger, the current flowing through the enlarged permanent magnet increases, and the eddy current loss also increases. Therefore, in order to reduce eddy current loss, Non-Patent Document 1 and the like describe that it is necessary to subdivide one pole of a magnet and cut off the flow of electricity with a surface coating film or an adhesive layer. However, it takes a lot of time and effort to increase the manufacturing cost.
JP 7-169633 A ((0040) to (0043), FIG. 1) JP-A-8-331784 ((0021) to (0023), FIG. 1) JP 2002-134311 A ((0087) to (0090)) Mita: "Eddy current analysis of surface magnet motor", '98 Motor Technology Symposium (1998)

本発明は上記した問題点を解消するもので、永久磁石と軟磁性材との間の不要なエアギャップを削減でき、かつ、永久磁石の形状の自由度が向上して永久磁石の磁力の有効利用が図れ、高い磁気特性を有する永久磁石埋設型の回転子とその製造方法を提供するものである。特にスプリングバックによる割れがなく、ボンド磁石部と軟磁性部との圧着強度が高い、安全性の高い回転子とその製造方法を提供するものである。   The present invention solves the above-described problems, can reduce unnecessary air gaps between the permanent magnet and the soft magnetic material, and improves the degree of freedom of the shape of the permanent magnet, thereby effectively using the magnetic force of the permanent magnet. The present invention provides a permanent magnet embedded rotor having high magnetic properties that can be used and a method for manufacturing the same. In particular, the present invention provides a highly safe rotor that is free from cracks due to springback and has a high pressure bonding strength between a bonded magnet portion and a soft magnetic portion, and a method for manufacturing the same.

本発明は、結合材および磁石粉末を主とするボンド磁石部と、結合材および軟磁性粉末を主とする軟磁性部からなる永久磁石埋設型の回転子であって、前記ボンド磁石部は磁極の両面を軟磁性部に埋設されていることを特徴とするものである。つまり、アトマイズ鉄粉やFe−Co合金粉末、ナノ結晶粉末などの高透磁率材料と希土類磁石粉末と熱硬化性樹脂混練物を、複動プレスにて加圧成形後250℃以下で硬化処理することにより、ヨーク一体型の永久磁石埋設型回転子を製造する。この製造方法は、少ない工数で成形することができ、しかも少ない樹脂量で高密度の成形体が得られるという特徴がある。また、接着剤などの層も不要であり、高特性の回転子とすることが出来る。   The present invention relates to a permanent magnet embedded rotor composed of a bond magnet part mainly composed of a binder and magnet powder, and a soft magnetic part mainly composed of a binder and soft magnetic powder, wherein the bond magnet part is a magnetic pole. The both surfaces of the magnetic material are embedded in the soft magnetic part. That is, a high permeability material such as atomized iron powder, Fe-Co alloy powder, and nanocrystal powder, a rare earth magnet powder, and a thermosetting resin kneaded material are cured at a temperature of 250 ° C. or less after pressure molding with a double-acting press. As a result, the yoke-integrated permanent magnet embedded rotor is manufactured. This manufacturing method is characterized in that it can be molded with a small number of man-hours, and a high-density molded body can be obtained with a small amount of resin. Further, a layer such as an adhesive is not required, and a high-performance rotor can be obtained.

IPMロータではリラクタンストルクを有効活用することでSPMロータよりもさらに優れたモータ出力のメリットが生じる。しかしリラクタンストルクを有効活用するということはロータヨークに過大な交番磁界がかかるので渦電流損失が顕著になる。その渦電流損失を避けるため、一般的には絶縁処理された薄板状の珪素鋼板を積層するが、本発明のような軟磁性部とボンド磁石部を一体成形するものでは電気伝導率を極めて下げる必要がある。SPMロータではこの点に関して全く考慮する必要はないが、本発明においては重要な技術要素である。よって、この回転子は周側面が前記軟磁性部で形成され、かつ前記軟磁性部の電気伝導率は20kS/m以下であることが好ましい。   In the IPM rotor, by using the reluctance torque effectively, a merit of motor output superior to that of the SPM rotor occurs. However, effectively utilizing the reluctance torque causes an excessive alternating magnetic field to be applied to the rotor yoke, so that eddy current loss becomes significant. In order to avoid the loss of eddy current, generally, a thin silicon steel plate with insulation treatment is laminated, but in the case where the soft magnetic portion and the bonded magnet portion are integrally formed as in the present invention, the electrical conductivity is extremely lowered. There is a need. In the SPM rotor, there is no need to consider this point at all, but it is an important technical element in the present invention. Therefore, it is preferable that the peripheral surface of the rotor is formed by the soft magnetic portion, and the electric conductivity of the soft magnetic portion is 20 kS / m or less.

実際の製造においては、500〜1000MPa程の高圧で圧縮成形する必要がある。そのため、スプリングバックによるクラックの発生が著しい。これは軟磁性部がスプリングバックにより約0.3%膨張するのに対し、ボンド磁石部ではスプリングバックにより約0.9%膨張するため、両者の差による残留応力が残るためである。軟磁性部の引張強度が約50MPaであるのに対して、ボンド磁石部の引張強度は約25MPaと弱いため、ボンド磁石部においてクラックが発生する。よってこの残留応力を所定の値以下にするための詳細な検討を行った結果、ボンド磁石部が回転子の周上に露出した露出面を有する回転子を設計する場合、この露出面の一箇所あたりの幅が回転子の全周の2%以下(0%を含まず)であればクラックの発生がなく、有用な回転子とすることができることが解った。これはボンド磁石部の形状に限らず、ほぼ一定の値であることが確認された。例えば図6に示す残留応力と露出面の露出率の関係で見れば、グラフの線一本分程度の差しか表れない。これは応力集中する部分が回転子の外周面側となるためであり、通常使用されるボンド磁石部の形状の範囲ではこの外周面での残留応力を低減させればクラックを抑制できることを知見したものである。   In actual production, it is necessary to perform compression molding at a high pressure of about 500 to 1000 MPa. For this reason, the occurrence of cracks due to springback is significant. This is because the soft magnetic part expands by about 0.3% by the spring back, whereas the bond magnet part expands by about 0.9% by the spring back, so that residual stress due to the difference between the two remains. The tensile strength of the soft magnetic part is about 50 MPa, whereas the tensile strength of the bonded magnet part is as weak as about 25 MPa, so that cracks occur in the bonded magnet part. Therefore, as a result of detailed examination for making this residual stress not more than a predetermined value, when designing a rotor having an exposed surface where the bonded magnet portion is exposed on the circumference of the rotor, one place on this exposed surface It has been found that if the per-width is 2% or less (not including 0%) of the entire circumference of the rotor, cracks do not occur and a useful rotor can be obtained. This was not limited to the shape of the bonded magnet part, but was confirmed to be a substantially constant value. For example, if the relationship between the residual stress and the exposure rate of the exposed surface shown in FIG. This is because the stress-concentrated portion is on the outer peripheral surface side of the rotor, and it has been found that cracks can be suppressed by reducing the residual stress on this outer peripheral surface in the range of the shape of the normally used bonded magnet part. Is.

また、回転子の断面内部にボンド磁石部の全体が埋設された回転子を設計する場合、回転子のボンド磁石部と周側面の間の最薄部tが0.3mm以上1.5mm以内とする必要がある。最薄部が0.3mm以下では成形時に軟磁性粉末をキャビティ中に振込み辛くするだけでなく、残留応力がこの最薄部に集中し回転子が割れてしまう。また、最薄部が1.5mmを超えるとこの最薄部で磁束が短絡し回転子としての磁気特性が落ちてしまう。この最薄部の範囲もボンド磁石部の形状に限らず、ほぼ一定の値であることが確認されている。回転子の外径は15mmから150mm程度が実用に好ましい。   Further, when designing a rotor in which the entire bonded magnet portion is embedded in the cross section of the rotor, the thinnest portion t between the bonded magnet portion and the peripheral side surface of the rotor is 0.3 mm or more and 1.5 mm or less. There is a need to. When the thinnest part is 0.3 mm or less, not only does the soft magnetic powder hardly be transferred into the cavity during molding, but also residual stress concentrates on the thinnest part and the rotor is cracked. On the other hand, if the thinnest part exceeds 1.5 mm, the magnetic flux is short-circuited at the thinnest part and the magnetic characteristics as a rotor are deteriorated. The range of the thinnest part is not limited to the shape of the bonded magnet part, and it has been confirmed that it is a substantially constant value. The outer diameter of the rotor is preferably about 15 mm to 150 mm for practical use.

500〜1000MPaの高圧で圧縮成形した場合の回転子の密度は、例えばRTB系のボンド磁石部で5.5〜6.0Mg/m、RTN系のボンド磁石部で5.4〜6.0Mg/mであり、Fe粉のボンド軟磁性部であれば6.0〜6.5Mg/mである。 The density of the rotor when compression-molded at a high pressure of 500 to 1000 MPa is, for example, 5.5 to 6.0 Mg / m 3 for an RTB-based bond magnet part, and 5.4 to 6.0 Mg for an RTN-based bond magnet part. / m is 3, is a 6.0~6.5Mg / m 3 if the bond soft portion of the Fe powder.

本発明の回転子として最も優位な形態として、ボンド磁石部は回転子中心側へ膨らむアーク形状であり、回転子が4〜12極の磁極部を有するように形成されているものが好ましい。このアーク形状は端部が薄く、中央部が厚いものが好ましい。また、別の形態として、ボンド磁石部は回転子中心側へ膨らむアーク形状が端部で連なって環状をなし、回転子が4〜12極の磁極部を有するように形成されているものでもよい。これにより磁極となる部分のボンド磁石部の比表面積が大きくなり、磁極中央での磁束量が大きくなるとともに、リラクタンス効果を狙い易い形状となるためである。   As the most advantageous form as the rotor of the present invention, it is preferable that the bonded magnet portion has an arc shape that swells toward the rotor center side, and the rotor is formed so as to have 4 to 12 pole magnetic pole portions. The arc shape preferably has a thin end and a thick center. As another form, the bonded magnet portion may be formed such that the arc shape that swells toward the center of the rotor is connected to the end portion to form an annular shape, and the rotor has 4 to 12 pole magnetic pole portions. . This is because the specific surface area of the bonded magnet portion at the magnetic pole portion is increased, the amount of magnetic flux at the magnetic pole center is increased, and the reluctance effect is easily achieved.

磁石粉末の平均粒径が50〜200μmであり、前記軟磁性粉末の平均粒径が1〜50μmであるものが好ましい。相互に粒径を変えることでボンド磁石部と軟磁性部の密着強度が高まり、クラックをさらに抑制できる回転子を製造できる。さらに好ましい磁石粉末の平均粒径は80〜150μmであり、さらに好ましい軟磁性粉末の平均粒径は5〜30μmである。   The magnet powder preferably has an average particle size of 50 to 200 μm and the soft magnetic powder has an average particle size of 1 to 50 μm. By changing the particle size to each other, the adhesion strength between the bonded magnet portion and the soft magnetic portion is increased, and a rotor that can further suppress cracks can be manufactured. A more preferable average particle size of the magnet powder is 80 to 150 μm, and a more preferable average particle size of the soft magnetic powder is 5 to 30 μm.

磁石粉末は、等方性のR−Fe−B系磁石粉末あるいはSm−Fe−N系磁石粉末であることが望ましい。もしくは、異方性のR−Fe−B系磁石粉末あるいはSm−Fe−N系磁石粉末であることが望ましい。磁石埋設型回転子では回転子の内部で磁束が短絡するので、例えばフェライト系ボンド磁石の様に残留磁束密度Brが0.4T未満だと回転子表面に必要充分な磁束を得ることができない。したがって、Br≧0.4T、保磁力Hcj≧600kA/mの希土類ボンド磁石を使用することが望ましい。
一方、軟磁性粉末はアトマイズ鉄粉、Fe−Co鉄粉、Fe基ナノ結晶磁性粉末などを用いて、電気伝導率は20kS/m以下であり、磁気特性がBm≧1.4T、Hc≦800A/mにすることが望ましい。電気伝導率が20kS/m未満であると、渦電流損を珪素鋼板などの絶縁積層品と略同等に低減することができる。また、Bmが低いと必要充分な磁束が得られず、またHcが高すぎるとモータ回転時のヒステリシス損が顕著になりモータ効率が著しく低下する。
The magnet powder is preferably an isotropic R—Fe—B magnet powder or Sm—Fe—N magnet powder. Alternatively, anisotropic R—Fe—B magnet powder or Sm—Fe—N magnet powder is desirable. In the magnet-embedded rotor, the magnetic flux is short-circuited inside the rotor, so that a necessary and sufficient magnetic flux cannot be obtained on the rotor surface if the residual magnetic flux density Br is less than 0.4 T, for example, as in a ferrite-based bonded magnet. Therefore, it is desirable to use a rare earth bonded magnet with Br ≧ 0.4T and coercive force Hcj ≧ 600 kA / m.
On the other hand, the soft magnetic powder uses atomized iron powder, Fe-Co iron powder, Fe-based nanocrystalline magnetic powder, etc., electric conductivity is 20 kS / m or less, magnetic properties are Bm ≧ 1.4T, Hc ≦ 800 A / m is desirable. When the electrical conductivity is less than 20 kS / m, the eddy current loss can be reduced substantially equivalent to that of an insulating laminated product such as a silicon steel plate. Also, if Bm is low, a necessary and sufficient magnetic flux cannot be obtained, and if Hc is too high, hysteresis loss during motor rotation becomes remarkable and motor efficiency is remarkably lowered.

また軟磁性粉末に、絶縁皮膜のコーテイングをなすことも好ましい。あるいは希土類磁石粉末に、絶縁皮膜コーテイングをなすことも好ましい。絶縁皮膜のコーティングを施すと電気抵抗が増加して、モータ回転時の渦電流損を低減することができる。   It is also preferable to coat the soft magnetic powder with an insulating film. Alternatively, it is also preferable to apply an insulating coating to the rare earth magnet powder. When an insulating film is applied, the electrical resistance increases and eddy current loss during motor rotation can be reduced.

一体型永久磁石回転子成形用原料としては、磁石粉末コンパウンド、軟磁性粉末コンパウンドに樹脂バインダー(結合剤)を添加する。結合剤としては熱硬化性樹脂を、磁石粉末コンパウンドであれば1〜5質量%、軟磁性粉末コンパウンドであれば0.1〜3質量%含むことが望ましい。   As a raw material for molding an integral permanent magnet rotor, a resin binder (binder) is added to a magnet powder compound and a soft magnetic powder compound. As the binder, it is desirable to contain a thermosetting resin in an amount of 1 to 5% by mass for a magnet powder compound and 0.1 to 3% by mass for a soft magnetic powder compound.

なお、ダイスが単純な円筒形であると、磁石をダイスから抜いた瞬間に成形体が膨張し、クラックを発生する。そこでダイス上面にテーパを設けると効果的に作用し、クラックの発生を抑制することができる。   If the die is a simple cylindrical shape, the molded body expands and cracks occur at the moment when the magnet is removed from the die. Therefore, if a taper is provided on the upper surface of the die, it works effectively, and the generation of cracks can be suppressed.

製造方法として、ボンド磁石部を結合材および平均粒径が50〜200μmの磁石粉末を主とする磁石粉末コンパウンドにより予備成形し、その後、軟磁性部を結合材および平均粒径が1〜50μmの軟磁性粉末を主とする軟磁性粉末コンパウンドによりボンド磁石部に接触するように予備成形し、その後前記ボンド磁石部と軟磁性部を予備成形の圧力よりも高い圧力で本成形して一体にし、その後熱硬化させる第1の製造方法を採用できる。すなわち、金型中に樹脂バインダーを1〜5質量%含む磁石粉末コンパウンドを充填後、成形圧力200MPaで加圧した後、樹脂バインダーを0.3〜2質量%含む軟磁性ヨーク部のコアピンを押し下げることにより、軟磁性粉末充填用のキャビティを形成し、軟磁性粉末コンパウンドを給粉し成形圧力200MPaで加圧した後、磁石粉末および軟磁性粉末成形物を複動プレスにより、成形圧力1000MPaで一体に本成形し、永久磁石式回転子を製造する。ここで、永久磁石回転子成形用金型は、上下パンチに4個以上の偶数のコアピンを有し、コアピンとパンチが独立または、連動して可動する機構を有する。永久磁石粉末が異方性磁石粉末の場合、少なくとも最終加圧時に磁界を印加して製造する。
IPMタイプのロータはロータ内の磁束の短絡を防ぐため、磁石と周側面の間の軟磁性部を薄肉にする必要がある。磁石をロータ内に後から挿入するタイプでは薄肉部の寸法が機械的な強度確保に制約を受けて設計の自由度が少ない。本発明の様に一体的に成形するものだとボンド磁石粉末と軟磁性粉末が成形段階で圧着される薄肉部が自由に設計できる。さらにはこの薄肉部を無くすことも可能である。予備成形と本成形に分けて成形することでボンド磁石部と軟磁性部の圧着力を高めることが可能である。これは粒径の粗い磁石粉末を先に予備成形することで、後から充填される粒径の細かな軟磁性粉末が一部ボンド磁石部側に入り込み、圧着力を高めるためである。従来の接着剤による接合では接着層の厚みがばらついたり、接着面の粗さによって接着強度が変わるなど、安定した接着強度を得ることは難しい。製品仕様として10MPa以上の接着強度を有することが明記されていても実質5MPa以上の接着強度を出すことが困難となる。対して上記の製法ではボンド磁石部と軟磁性部の圧着力はせん断応力で10MPa以上、さらには15MPa以上となる。
As a manufacturing method, the bonded magnet part is preformed with a binder and a magnet powder compound mainly composed of magnet powder having an average particle diameter of 50 to 200 μm, and then the soft magnetic part is bonded to the binder and the average particle diameter of 1 to 50 μm. Preliminarily molded so as to come into contact with the bonded magnet part by a soft magnetic powder compound mainly composed of soft magnetic powder, and then the bonded magnet part and the soft magnetic part are integrally formed at a pressure higher than the pressure of the preformed, Thereafter, a first manufacturing method in which thermosetting is performed can be employed. That is, by filling a magnetic powder compound containing 1 to 5% by mass of a resin binder in a mold, pressurizing at a molding pressure of 200 MPa, and then pressing down the core pin of the soft magnetic yoke part containing 0.3 to 2% by mass of the resin binder After forming the cavity for filling the soft magnetic powder, supplying the soft magnetic powder compound and pressurizing it at a molding pressure of 200 MPa, the magnet powder and the soft magnetic powder molding are integrally formed at a molding pressure of 1000 MPa by a double action press. Molding to produce a permanent magnet rotor. Here, the permanent magnet rotor molding die has four or more even-numbered core pins in the upper and lower punches, and has a mechanism in which the core pins and the punches can move independently or in conjunction with each other. When the permanent magnet powder is anisotropic magnet powder, it is manufactured by applying a magnetic field at least during final pressurization.
In the IPM type rotor, in order to prevent a short circuit of magnetic flux in the rotor, it is necessary to make the soft magnetic part between the magnet and the peripheral side surface thin. In the type in which the magnet is inserted into the rotor later, the dimension of the thin wall portion is limited by securing the mechanical strength, and the degree of freedom in design is small. When integrally molded as in the present invention, a thin portion where the bonded magnet powder and soft magnetic powder are pressure-bonded at the molding stage can be freely designed. Furthermore, it is possible to eliminate this thin portion. It is possible to increase the pressure-bonding force between the bonded magnet portion and the soft magnetic portion by separately forming the preforming and the main forming. This is because by preliminarily molding the magnet powder having a coarse particle diameter, a part of the soft magnetic powder having a small particle diameter to be filled later enters the bonded magnet portion side, thereby increasing the pressing force. In conventional bonding using an adhesive, it is difficult to obtain a stable adhesive strength such as the thickness of the adhesive layer varies or the adhesive strength varies depending on the roughness of the adhesive surface. Even if it is clearly stated that the product specification has an adhesive strength of 10 MPa or more, it is difficult to achieve an adhesive strength of substantially 5 MPa or more. On the other hand, in the above manufacturing method, the press-bonding force between the bonded magnet portion and the soft magnetic portion is 10 MPa or more, further 15 MPa or more in terms of shear stress.

また、前記ボンド磁石部を結合材および平均粒径が50〜200μmの磁石粉末を主とする磁石粉末コンパウンドにより予備成形し、前記軟磁性部を結合材および平均粒径が1〜50μmの軟磁性粉末を主とする軟磁性粉末コンパウンドにより別途予備成形し、両予備成形体を組合せ予備成形の圧力よりも高い圧力で本成形して一体にし、その後熱硬化させる第2の製造方法も採用することもできる。この製法であれば、コアピンを複雑に動作させる必要がなくなるため、成形時間を大幅に短縮することができる。これによるボンド磁石部と軟磁性部の圧着力はせん断応力で5MPa以上、さらには5.5MPa以上となる。   The bonded magnet portion is pre-formed with a binder and a magnet powder compound mainly composed of magnet powder having an average particle size of 50 to 200 μm, and the soft magnetic portion is soft magnetically bonded to the binder and the average particle size of 1 to 50 μm. A second manufacturing method is also adopted in which the powder is mainly preformed separately with a soft magnetic powder compound, the two preforms are integrally molded at a pressure higher than the pressure of the combined preforming, and then thermally cured. You can also. With this manufacturing method, since it is not necessary to operate the core pin in a complicated manner, the molding time can be greatly shortened. As a result, the bonding force between the bonded magnet portion and the soft magnetic portion is 5 MPa or more, further 5.5 MPa or more in terms of shear stress.

また、軟磁性粉末コンパウンドを圧縮成形した後、磁石粉末コンパウンドを軟磁性部に接触するように予備成形し、この予備成形圧力よりも大きい成形圧力を全体に加えて一体成形する製造方法も採用することもできる。   In addition, after the soft magnetic powder compound is compression molded, the magnet powder compound is preformed so as to come into contact with the soft magnetic part, and a molding method in which a molding pressure larger than the preforming pressure is applied to the whole is integrally formed. You can also.

上記製造方法において、永久磁石1極を細分割するように金型中に磁石粉末用のキャビティを複数形成し、その周囲に軟磁性粉末と熱硬化性樹脂の量、もしくは軟磁性粉末のFe重量比を任意に組合わせた低導電率の軟磁性粉末コンパウンドを配置することにより電気抵抗を増加させ、磁石の渦電流損を低減させることも好ましい。従来の製造法では、1極分の磁石を細分割し表面塗装膜や接着層を付与し組立てることにより、電気の流れを断ち切り渦電流損失を低減させていた。1極分の磁石を予め作ってから切断するにしても、出来上がり形状に合せ形状の異なる小磁石を用いるにしても、工程数が多くなり、製造コストが増加する。これに対し本発明の製造法では、一体で製造できるため工程数が少なく、製造コストを低減できる。モータが大型化するほど永久磁石に流れる電流が増加し、渦電流損も増加するため、このような製造法が効果的となる。   In the above manufacturing method, a plurality of cavities for magnet powder are formed in a mold so that one pole of a permanent magnet is subdivided, and the amount of soft magnetic powder and thermosetting resin around it or the weight of Fe of soft magnetic powder It is also preferred to increase the electrical resistance and reduce the eddy current loss of the magnet by arranging a low-conductivity soft magnetic powder compound with any combination of ratios. In the conventional manufacturing method, magnets for one pole are subdivided and a surface coating film or an adhesive layer is applied and assembled to cut off the flow of electricity and reduce eddy current loss. Even if a magnet for one pole is made in advance and then cut, or a small magnet having a different shape according to the finished shape is used, the number of processes increases and the manufacturing cost increases. On the other hand, in the manufacturing method of the present invention, since it can be manufactured integrally, the number of steps is small and the manufacturing cost can be reduced. Since the current flowing through the permanent magnet increases and the eddy current loss increases as the motor becomes larger, such a manufacturing method becomes effective.

本発明は、以上記述のように樹脂バインダー等の結合剤を含む軟磁性粉末とボンド磁石粉とで回転子を一体成形することで磁石からの磁束を有効活用できる、リラクタンストルクを有効活用できる、高い寸法精度が得られる、組立て工数の削減と精度向上を両立できる、等の利点が得られる。また回転子中のボンド磁石部を所定の形状にすることで、高い機械強度が得られ、スプリングバックによる割れを抑制でき、また、粒径と工程を工夫することでボンド磁石部と軟磁性部との圧着強度が良好な信頼性の高い回転子を提供できる。   As described above, the present invention can effectively utilize the magnetic flux from the magnet by integrally forming the rotor with the soft magnetic powder containing the binder such as the resin binder and the bonded magnet powder, and can effectively utilize the reluctance torque. Advantages such as high dimensional accuracy, reduction in assembly man-hours, and improvement in accuracy can be obtained. Moreover, high mechanical strength can be obtained by making the bonded magnet part in the rotor a predetermined shape, cracks due to springback can be suppressed, and the bond magnet part and soft magnetic part can be improved by devising the particle size and process. And a highly reliable rotor with good pressure bonding strength.

以下、本発明の実施形態について図面とともに説明する。
先ず、本発明の一実施例に関わる永久磁石回転子の模式断面図を図1(a)に示す。図は希土類ボンド磁石埋設型の磁石回転子で、軟磁性粉末よりなるヨークと一体成形されて構成されている。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a schematic cross-sectional view of a permanent magnet rotor according to an embodiment of the present invention is shown in FIG. The figure shows a rare earth bonded magnet-embedded magnet rotor which is integrally formed with a yoke made of soft magnetic powder.

図1(a)の回転子を例として、本発明の永久磁石回転子の製造方法を図2に示す。図2(a)は、図1の回転子の製造に用いる上パンチを示す斜視図である。図1の4箇所のボンド磁石部に対応して上パンチ3、下パンチ3’は各4本づつのコアピンから成る。図2(a)のA−A’断面について、図2(b)〜(f)に成形方法を示す。   Taking the rotor of FIG. 1 (a) as an example, a method for manufacturing a permanent magnet rotor of the present invention is shown in FIG. FIG. 2A is a perspective view showing an upper punch used for manufacturing the rotor of FIG. Corresponding to the four bonded magnet portions in FIG. 1, the upper punch 3 and the lower punch 3 'are each composed of four core pins. With respect to the A-A ′ cross section of FIG. 2A, the forming method is shown in FIGS.

成形装置は、ダイス6と、その内部に保持された磁石部を圧縮成形する上下パンチ3および3’と、ヨーク部を圧縮成形する上下パンチ4および4’、製品中央の穴部を形成するコアピン5とを有する。始めに図2(b)のように下パンチ3’を下げてボンド磁石部の成形キャビティを形成し、希土類磁石粉末と熱硬化性樹脂との混練物である磁石粉末コンパウンド7を給粉する。次に、図2(c)のように、上パンチ3を下降させて成形圧力200MPaで予備加圧し、回転子の所望厚さよりも厚い予備成形体を形成する。次に、図2(d)のように下パンチ4’を下げてヨーク部の成形キャビティを形成し、アトマイズ鉄粉やFe−Co合金粉末、ナノ結晶粉末などの高透磁率材料と熱硬化性樹脂の混練物である軟磁性粉末コンパウンド8を充填する。その後図2(e)のように上パンチ4を下降させて予備成形を行う、最後に図2(f)のように上パンチ3および4で成形圧力1000MPaにて最終加圧による本成形を行なう。なお、上パンチ3と4、および下パンチ3’と4’とに僅かな段差を設けておくと、ボンド磁石部と軟磁性部とのスプリングバックの差を加味して、最終的に厚み寸法を揃えることができる。磁石粉末として異方性磁石粉末を用いる場合は、最終加圧時に磁界を印加する。   The forming apparatus includes a die 6, upper and lower punches 3 and 3 ′ for compressing and molding a magnet portion held therein, upper and lower punches 4 and 4 ′ for compressing and forming a yoke portion, and a core pin that forms a hole in the center of the product. And 5. First, as shown in FIG. 2B, the lower punch 3 'is lowered to form a molding cavity of the bonded magnet portion, and the magnet powder compound 7 which is a kneaded product of rare earth magnet powder and thermosetting resin is fed. Next, as shown in FIG. 2C, the upper punch 3 is lowered and pre-pressurized at a molding pressure of 200 MPa to form a preform that is thicker than the desired thickness of the rotor. Next, as shown in FIG. 2 (d), the lower punch 4 'is lowered to form a molding cavity of the yoke portion, and a high permeability material such as atomized iron powder, Fe-Co alloy powder, nanocrystal powder, and the like, and thermosetting. A soft magnetic powder compound 8 that is a kneaded resin is filled. Thereafter, the upper punch 4 is lowered as shown in FIG. 2 (e) to perform preliminary molding, and finally final molding is performed with the upper punches 3 and 4 at a molding pressure of 1000 MPa as shown in FIG. 2 (f). . If a slight step is provided between the upper punches 3 and 4 and the lower punches 3 ′ and 4 ′, the thickness dimension is finally taken into account by taking into account the difference in spring back between the bonded magnet portion and the soft magnetic portion. Can be aligned. When anisotropic magnet powder is used as the magnet powder, a magnetic field is applied during final pressurization.

最後に上パンチを引き上げ、下パンチを上昇させて成形装置から成形体を取り出し、必要に応じて250℃以下で加熱しながら硬化処理する。ついで回転軸(図1では省略)と一体化し、着磁を施すことにより、ヨーク一体型の永久磁石埋設型回転子が得られる。なお、図2では磁石粉末コンパウンドで予備生形体を構成した後に軟磁性粉末コンパウンドを給粉しているが、同様にして、軟磁性粉末コンパウンドで予備成形体を構成した後に磁石粉末コンパウンドを給粉しても良い。この場合に圧着強度は低下するものの、磁石が極めて薄肉でキャビティ内で仮成形体を保持するのが困難な場合などには、有効な手法となる。
また、この製造方法をさらに応用して回転軸まで一体成形することも可能である。
Finally, the upper punch is pulled up, the lower punch is raised, the molded body is taken out from the molding apparatus, and is cured while being heated at 250 ° C. or lower as necessary. Next, it is integrated with a rotating shaft (not shown in FIG. 1) and magnetized, whereby a yoke-integrated permanent magnet embedded rotor is obtained. In FIG. 2, the soft magnetic powder compound is fed after the preliminary green body is formed with the magnet powder compound. Similarly, the magnetic powder compound is fed after the preform is formed with the soft magnetic powder compound. You may do it. In this case, although the pressure bonding strength is reduced, it is an effective method when the magnet is extremely thin and it is difficult to hold the temporary molded body in the cavity.
Further, this manufacturing method can be further applied to integrally form the rotating shaft.

図2に示す成形方法によれば、単一の成形装置内に原料を供給し、予備成形と本成形を行うことにより、接着や組立ての工程を要せず、ボンド磁石部の周囲全体が軟磁性部に囲まれたヨーク一体型の永久磁石回転子が得られる。従って、従来よりも構造信頼性の高い回転子が低コストで製作できる。   According to the molding method shown in FIG. 2, by supplying the raw material into a single molding apparatus and performing the preliminary molding and the main molding, the entire periphery of the bonded magnet portion is soft without the need for bonding or assembling processes. A yoke-integrated permanent magnet rotor surrounded by the magnetic part is obtained. Therefore, a rotor with higher structural reliability than the conventional one can be manufactured at low cost.

スプリングバックによるクラックの発生を抑制するため、ダイスのキャビティ上部をテーパ化して急激なスプリングバックの発生を抑制する、ダイスのキャビティ面の面粗さを小さくして摩擦抵抗を低減する、潤滑剤などにより摩擦抵抗を低減する、などの手段が採用できる。   To suppress the occurrence of cracks due to springback, taper the upper part of the die cavity to suppress sudden springback, reduce the surface roughness of the die cavity surface, reduce frictional resistance, etc. A means such as reducing frictional resistance can be adopted.

結合剤は熱硬化性樹脂が好ましい。例えばエポキシ樹脂、フェノール樹脂、ユリア樹脂、メラミン樹脂、ポリエステル樹脂等が適宜使用できる。磁石粉末質量に対する含有量は、0.1〜5質量%が好ましく、1.0〜4質量%がより好ましい。軟磁性粉末に対する含有量は0.1〜3質量%が好ましく、0.5〜2質量%がより好ましい。結合剤の含有量が少なすぎると機械強度が著しく低下し、結合剤の含有量が多すぎると磁気特性が著しく低下する。   The binder is preferably a thermosetting resin. For example, an epoxy resin, a phenol resin, a urea resin, a melamine resin, a polyester resin, or the like can be used as appropriate. 0.1-5 mass% is preferable and, as for content with respect to magnet powder mass, 1.0-4 mass% is more preferable. The content with respect to the soft magnetic powder is preferably 0.1 to 3% by mass, and more preferably 0.5 to 2% by mass. If the binder content is too low, the mechanical strength is significantly reduced, and if the binder content is too high, the magnetic properties are significantly reduced.

軟磁性粉末と結合剤、もしくは磁石粉末(特に希土類磁石粉末)と結合剤を調整してコンパウンドとする。このコンパウンド中には、酸化防止剤や潤滑剤が含まれていてもよい。酸化防止剤は、磁石粉末の酸化を防止して磁石の磁気特性の低下を防ぐのに寄与する。また、コンパウンドの混練・成形の際に熱的安定性の向上に寄与し、少ない結合剤添加量で良好な成形性を保てる。酸化防止剤は、既知のものを使用でき、例えば、トコフェロール、アミン系化合物、アミノ酸系化合物、ニトロカルボン酸類、ヒドラジン化合物、シアン化合物、硫化物等の、金属イオン、特にFe成分に対しキレート化合物を生成するキレート化剤などが使用できる。
潤滑剤は、コンパウンドの混練・成形の際に流動性を向上させるため、より少ない結合剤添加量で同等の特性を得ることができる。潤滑剤は既知のものを使用でき、例えば、ステアリン酸またはその金属塩、脂肪酸、シリコーンオイル、各種ワックス、脂肪酸などが使用できる。
また、他に安定化剤、成形助剤等の各種添加剤を添加することもできる。コンパウンドは混合機や攪拌機を用いて混合する。
Soft magnetic powder and binder, or magnet powder (especially rare earth magnet powder) and binder are adjusted to form a compound. This compound may contain an antioxidant and a lubricant. The antioxidant contributes to preventing the magnetic powder from being deteriorated by preventing the magnetic powder from being oxidized. Further, it contributes to the improvement of thermal stability during compound kneading and molding, and good moldability can be maintained with a small amount of binder added. As the antioxidant, known ones can be used, for example, tocopherols, amine compounds, amino acid compounds, nitrocarboxylic acids, hydrazine compounds, cyanide compounds, sulfides, etc. The resulting chelating agent can be used.
Since the lubricant improves the fluidity when the compound is kneaded and molded, the same characteristics can be obtained with a smaller amount of the binder. As the lubricant, known ones can be used. For example, stearic acid or a metal salt thereof, fatty acid, silicone oil, various waxes, fatty acid and the like can be used.
In addition, various additives such as a stabilizer and a molding aid can be added. The compound is mixed using a mixer or a stirrer.

磁石粉末として、Smを主とする希土類元素と、Coを主とする遷移金属とを基本成分とするSm−Co系磁石粉末や、R(ただし、RはYを含む希土類元素のうち少なくとも1種)と、T(Feを主とする遷移金属)と、Bとを基本成分とするR−T−B系磁石粉末、Smを主とする希土類元素と、T(Feを主とする遷移金属)と、Nを基本成分とするR−T−N系磁石粉末、さらにはこれらの混合磁石粉末が好ましい。   As the magnet powder, an Sm—Co-based magnet powder containing a rare earth element mainly composed of Sm and a transition metal mainly composed of Co, or R (where R is a rare earth element containing Y). ), T (transition metal mainly composed of Fe), R-T-B magnet powder mainly composed of B, rare earth element mainly composed of Sm, and T (transition metal mainly composed of Fe) R-T-N magnet powders containing N as a basic component, and mixed magnet powders thereof are preferred.

図10は、本発明の他の実施例による永久磁石回転子の模式断面図である。図10(a)は1磁極に対して複数の永久磁石を有する回転子であり、図10(b)は1磁極に対して複数の湾曲した円弧状の永久磁石を有する回転子である。本発明の製造方法により、このような複雑な形状の永久磁石と多数の極薄な軟磁性部分とを層状に設置することが可能となる。図10のような層状構造の回転子は、図1のような単層構造に比べ、より多くのリラクタンストルクを発生させることができる。   FIG. 10 is a schematic cross-sectional view of a permanent magnet rotor according to another embodiment of the present invention. FIG. 10A shows a rotor having a plurality of permanent magnets for one magnetic pole, and FIG. 10B shows a rotor having a plurality of curved arc-shaped permanent magnets for one magnetic pole. According to the manufacturing method of the present invention, it becomes possible to install a permanent magnet having such a complicated shape and a large number of extremely thin soft magnetic portions in layers. A rotor having a layered structure as shown in FIG. 10 can generate more reluctance torque than a single layer structure as shown in FIG.

図11は、本発明の他の実施例による永久磁石回転子の模式断面図である。本発明の製造方法により、このような極薄部分を有する複雑な形状の永久磁石が可能となり、永久磁石の磁力の有効利用が図れる永久磁石埋設型回転子を提供することができる。   FIG. 11 is a schematic cross-sectional view of a permanent magnet rotor according to another embodiment of the present invention. According to the manufacturing method of the present invention, a permanent magnet having a complicated shape having such an ultrathin portion is possible, and a permanent magnet embedded rotor capable of effectively using the magnetic force of the permanent magnet can be provided.

以下、本発明の永久磁石回転子を用いた実施例を、図面を参照して説明する。
(実施例1,比較例1)
スプリングバックによる回転子のクラックの発生を抑制するため、回転子形状、ボンド磁石部の形状を多々変更し、原因を究明した。図8(a)は検討当初のクラックが発生した回転子の断面形状(比較例1)である。1はボンド磁石部、2が軟磁性部である。結合材としてエポキシ樹脂を磁石粉末に対して3質量%、軟磁性粉末に対して1.1質量%添加した。潤滑材としてステアリン酸カルシウムを両粉末重量に対して0.3質量%添加した。またボンド磁石部は回転子の軸断面から見て回転子中心側に凹むアーク形状が端部で連なって環状をなした形状である。連なった端部は回転子の周側面に露出している。回転子の外径は50mm、ボンド磁石部1の厚みは5mmである。モータの回転軸方向の長さは100mmである。ボンド磁石部1の回転子の周側面に露出した露出面(以後、単に露出面とする)は幅が広く、回転子の全周に対する幅(以下、露出率とする)は1箇所あたり3.8%であった。図8(b)はダイスから圧縮成形した回転子成形体を取り出し、変形した後の引張応力の分布を示すものである。視覚化するために変位量を2000倍に拡大している。最も引張応力がかかる部分は磁石の露出面であり、その位置での引張応力は200MPaであった。
これに対して、図1のようにボンド磁石部を1極毎に分け、回転子の軸断面で見た場合、端部よりも中央部を厚くし、両端部を露出面としたアーク形状に設計変更を行った。ボンド磁石部は中央部が5mmと最も厚く、端部が1mmと薄い形状である。隣接するボンド磁石部の端部同士も間隔を空け、磁極間で磁束の短絡がないようにした。露出率は0.6%であった。図1の形状では最も引張応力がかかる部分は磁石の露出面であり、その位置での引張応力は2MPaであった。
図6はこの露出率と局部での最大の残留応力の関係を示す図である。軟磁性部のみの引張強度は約25MPaであることを考慮し、残留応力が約20MPa以下となるように設計すると露出率は2%以下とすべきことが解る。
なお、この実施例1の回転子と後述の実施例3の回転子を比較した場合、表1に示すようにボンド磁石部の回転子全体の断面に対する面積比率はほぼ同等でありながら、モータ出力は実施例1の方が顕著に高いことから回転子として優秀な性能を持っていることが解る。
Hereinafter, embodiments using the permanent magnet rotor of the present invention will be described with reference to the drawings.
(Example 1, Comparative Example 1)
In order to suppress the occurrence of cracks in the rotor due to springback, the rotor shape and the shape of the bonded magnet were changed in many ways, and the cause was investigated. FIG. 8A shows the cross-sectional shape (comparative example 1) of the rotor where cracks at the beginning of the study occurred. Reference numeral 1 is a bonded magnet portion, and 2 is a soft magnetic portion. As a binder, epoxy resin was added in an amount of 3% by mass with respect to the magnet powder and 1.1% by mass with respect to the soft magnetic powder. As a lubricant, calcium stearate was added in an amount of 0.3% by mass based on the weight of both powders. In addition, the bonded magnet portion has an annular shape in which the arc shape recessed toward the center of the rotor as viewed from the axial cross section of the rotor is continuous at the end. The connected end portion is exposed on the peripheral side surface of the rotor. The outer diameter of the rotor is 50 mm, and the thickness of the bonded magnet part 1 is 5 mm. The length of the motor in the rotation axis direction is 100 mm. An exposed surface (hereinafter simply referred to as an exposed surface) exposed on the peripheral side surface of the rotor of the bond magnet unit 1 has a wide width, and a width with respect to the entire periphery of the rotor (hereinafter referred to as an exposure rate) is 3. It was 8%. FIG. 8B shows the distribution of tensile stress after the rotor molded body compression-molded from the die is taken out and deformed. The displacement is enlarged 2000 times for visualization. The portion where the most tensile stress was applied was the exposed surface of the magnet, and the tensile stress at that position was 200 MPa.
On the other hand, as shown in FIG. 1, when the bonded magnet part is divided for each pole and viewed from the axial cross section of the rotor, the center part is thicker than the end part, and the arc shape has both end parts exposed. A design change was made. The bonded magnet portion has the thickest center portion of 5 mm and the thin end portion of 1 mm. The ends of adjacent bonded magnet portions are also spaced apart so that no magnetic flux is short-circuited between the magnetic poles. The exposure rate was 0.6%. In the shape of FIG. 1, the portion where the tensile stress is most applied is the exposed surface of the magnet, and the tensile stress at that position is 2 MPa.
FIG. 6 is a diagram showing the relationship between the exposure rate and the maximum residual stress in the local area. Considering that the tensile strength of only the soft magnetic part is about 25 MPa, it is understood that the exposure rate should be 2% or less when the residual stress is designed to be about 20 MPa or less.
In addition, when the rotor of Example 1 and the rotor of Example 3 described later are compared, as shown in Table 1, the area ratio of the bonded magnet portion to the entire rotor cross section is substantially the same, but the motor output Since Example 1 is significantly higher, it can be seen that it has excellent performance as a rotor.

Figure 2005020991
Figure 2005020991

(比較例2)
図9に示す、別のボンド磁石部の形状を持つ回転子の設計を行った。1はボンド磁石部、2が軟磁性部である。ボンド磁石部は回転子の軸断面から見て長方形の形状であり、端部が露出面になっている。また回転子の外径は50mm、ボンド磁石部1の厚みは5mmである。露出率は切れ込みの部分の長さも含めた外周の長さに対する露出部の長さにより求めた。ボンド磁石部の端部の露出率は1箇所あたり3.5%であった。図9の形状では最も引張応力がかかる部分は磁石の露出面であり、その位置での引張応力は183MPaであった。
露出率と局部での最大の残留応力の関係を解析したところ、1〜2%程度の数値の違いはあるが、図6と同じ様相の関係を示すことが解った。ボンド磁石部の中央部や端部の肉厚を変更して応力解析しても同様の結果を示すことが解っている。
(Comparative Example 2)
A rotor having another bond magnet portion shape shown in FIG. 9 was designed. Reference numeral 1 is a bonded magnet portion, and 2 is a soft magnetic portion. The bonded magnet portion has a rectangular shape when viewed from the axial cross section of the rotor, and the end portion is an exposed surface. The outer diameter of the rotor is 50 mm, and the thickness of the bonded magnet portion 1 is 5 mm. The exposure rate was determined from the length of the exposed portion relative to the length of the outer periphery including the length of the cut portion. The exposure rate of the edge part of a bonded magnet part was 3.5% per location. In the shape of FIG. 9, the portion where the most tensile stress is applied is the exposed surface of the magnet, and the tensile stress at that position is 183 MPa.
When the relationship between the exposure rate and the maximum residual stress in the local area was analyzed, it was found that the same aspect relationship as in FIG. It has been found that the same result is obtained even if the stress analysis is performed by changing the thickness of the central part or the end part of the bonded magnet part.

(実施例2)
露出部を無くし、ボンド磁石部と周側面の間の最薄部(以後、単に最薄部とする)を0.3mmとして設計した図3の形状では最も引張応力がかかる部分は軟磁性部の最薄部であり、その位置での引張応力は19MPaであった。図8、9に示す形状では軟磁性部2がボンド磁石部1により内周側と外周側に分割されており、外周面に形成された軟磁性部2の各々が外周側へ自由に膨張し、残留応力が緩和されることを想定していたが、実際は図3にしめす形状の方がクラックが抑えられることが解った。
図7はこの最薄部の幅と局部での最大の残留応力の関係を示す図である。軟磁性粉末の引張強度は約25MPaであることを考慮し、残留応力が約20MPa以下となるように設計すると最薄部は0.3mm以上とする必要があることが解る。但し、最薄部の幅が1.5mmを超えると最薄部での磁束の短絡が著しいため、最薄部の幅は1.5mm以下とする必要がある。
(Example 2)
In the shape of FIG. 3 where the exposed part is eliminated and the thinnest part between the bonded magnet part and the peripheral side surface (hereinafter simply referred to as the thinnest part) is designed to be 0.3 mm, the part where the most tensile stress is applied is the soft magnetic part. It was the thinnest part, and the tensile stress at that position was 19 MPa. 8 and 9, the soft magnetic part 2 is divided into an inner peripheral side and an outer peripheral side by the bonded magnet part 1, and each of the soft magnetic parts 2 formed on the outer peripheral surface freely expands to the outer peripheral side. Although it was assumed that the residual stress was alleviated, it was actually found that the shape shown in FIG.
FIG. 7 is a diagram showing the relationship between the width of the thinnest part and the maximum residual stress at the local part. Considering that the tensile strength of the soft magnetic powder is about 25 MPa, it is understood that the thinnest portion needs to be 0.3 mm or more when the residual stress is designed to be about 20 MPa or less. However, if the width of the thinnest part exceeds 1.5 mm, magnetic flux short-circuiting is remarkable in the thinnest part, so the width of the thinnest part needs to be 1.5 mm or less.

(実施例3)
図4に示す、別のボンド磁石部の形状を持つ回転子の設計を行った。1はボンド磁石部、2が軟磁性部である。ボンド磁石部は回転子の軸断面から見て長方形の形状とした。回転子の外径は50mm、ボンド磁石部1の厚みは5mm、横幅は25mmである。全体が軟磁性部に埋設されており、軟磁性部の最薄部tの幅は1.3mmであった。図4(b)はダイスから圧縮成形した回転子成形体を取り出し、変形した後の引張応力の分布を示すものである。視覚化するために変位量を2000倍に拡大している。最も引張応力がかかる部分はヨーク最薄部であり、その位置での引張応力は11MPaであった。
薄肉部と局部での最大の残留応力の関係を解析したところ、2〜4%程度の数値の違いはあるが、図7と同じ様相の関係を示すことが解った。ボンド磁石部の肉厚を変更して応力解析しても同様の結果を示すことが解っている。
Example 3
A rotor having another bond magnet portion shape shown in FIG. 4 was designed. Reference numeral 1 is a bonded magnet portion, and 2 is a soft magnetic portion. The bonded magnet portion was rectangular when viewed from the axial cross section of the rotor. The outer diameter of the rotor is 50 mm, the thickness of the bonded magnet part 1 is 5 mm, and the lateral width is 25 mm. The whole was embedded in the soft magnetic part, and the width of the thinnest part t of the soft magnetic part was 1.3 mm. FIG. 4B shows the distribution of tensile stress after the rotor molded body compression molded from the die is taken out and deformed. The displacement is enlarged 2000 times for visualization. The portion where the most tensile stress was applied was the yoke thinnest portion, and the tensile stress at that position was 11 MPa.
When the relationship between the maximum residual stress at the thin portion and the local portion was analyzed, it was found that there was a difference in the numerical value of about 2 to 4%, but the same aspect relationship as in FIG. 7 was shown. It has been found that the same result is obtained even if the stress analysis is performed by changing the thickness of the bonded magnet portion.

(実施例4)
図5に示す、別のボンド磁石部の形状を持つ回転子の設計を行った。1はボンド磁石部、2が軟磁性部である。ボンド磁石部は回転子の軸断面から見て円弧形状の外周を有している。回転子の外径は50mm、ボンド磁石部1の厚みは最大の厚みが7mm、横幅は35mmである。ボンド磁石部は全体が軟磁性部に埋設されており、円弧状の外周は回転子の外周部に沿った極率を持つ。最薄部は軟磁性部の外周側であり、一定の厚さの薄肉部がボンド磁石部の円弧状の外周に沿って形成されている。この薄肉部tの厚みは1mmであった。図5(b)はダイスから圧縮成形した回転子成形体を取り出し、変形した後の引張応力の分布を示すものである。視覚化するために変位量を2000倍に拡大している。最も引張応力がかかる部分は軟磁性部の最薄部であり、その位置での引張応力は11MPaであった。
最薄部と局部での最大の残留応力の関係を解析したところ、2〜3%程度の数値の違いはあるが、図7と同じ様相の関係を示すことが解った。ボンド磁石部の肉厚を変更して応力解析しても同様の結果を示すことが解っている。
(Example 4)
A rotor having the shape of another bonded magnet portion shown in FIG. 5 was designed. Reference numeral 1 is a bonded magnet portion, and 2 is a soft magnetic portion. The bonded magnet portion has an arc-shaped outer periphery when viewed from the axial cross section of the rotor. The outer diameter of the rotor is 50 mm, the maximum thickness of the bonded magnet part 1 is 7 mm, and the lateral width is 35 mm. The bond magnet portion is entirely embedded in the soft magnetic portion, and the arc-shaped outer periphery has a polarity along the outer periphery of the rotor. The thinnest part is the outer peripheral side of the soft magnetic part, and a thin part with a constant thickness is formed along the arc-shaped outer periphery of the bond magnet part. The thickness of the thin portion t was 1 mm. FIG. 5B shows the distribution of tensile stress after the rotor molded body compression molded from the die is taken out and deformed. The displacement is enlarged 2000 times for visualization. The portion where the most tensile stress was applied was the thinnest portion of the soft magnetic portion, and the tensile stress at that position was 11 MPa.
When the relationship between the maximum residual stress at the thinnest part and the local part was analyzed, it was found that there was a difference of about 2 to 3%, but the same aspect relationship as in FIG. 7 was shown. It has been found that the same result is obtained even if the stress analysis is performed by changing the thickness of the bonded magnet portion.

(実施例5)
回転子の圧縮成形方法として、軟磁性部とボンド磁石部の圧縮成形の順序について次の3つの手法で検討を行った。結合材としてエポキシ樹脂を磁石粉末に対して3質量%、軟磁性粉末に対して1.1質量%添加した。
(1)結合材と平均粒径が50〜200μmの磁石粉末を主とするコンパウンドを予備成形して予備成形体とし、次に結合材と平均粒径が1〜50μmの軟磁性粉末コンパウンドを主とする前記第1の予備成形体に隣接するように金型内に給粉して予備成形し、その後予備成形圧力よりも大きい成形圧力を印加して一体成形する第1の製造方法。
(2)軟磁性粉末コンパウンドの予備成形体と、磁石粉末コンパウンドの予備成形体を各々成形し、前記両方の予備成形体を組合せて金型内に配置し、前記予備成形体を成形する成形圧力よりも大きい成形圧力を加えて本成形し一体にする第2の製造方法。
(3)軟磁性粉末コンパウンドを予備成形して予備成形体とし、次に磁石粉末コンパウンドを前記第1の予備成形体に隣接するように金型内に給粉して予備成形し、その後予備成形圧力よりも大きい成形圧力を印加して一体成形する第3の製造方法。
この3つの手法により図1に示す同一形状の回転子を製造し、軟磁性部とボンド磁石部の間の圧着力を測定した。軟磁性粉末は平均粒径31.2μm(Sympatec社製、HEROS RODOSにより測定)のものを使用し、磁石粉末は平均粒径96.9μmのものを使用した。磁石粉末コンパウンドには結合剤として熱硬化性樹脂(エポキシ樹脂)を磁粉質量に対して3質量%添加し、また、潤滑剤としてステアリン酸カルシウムを磁粉質量に対して0.5質量%添加した。軟磁性粉末コンパウンドには結合剤として熱硬化性樹脂(エポキシ樹脂)を磁粉質量に対して1.1質量%添加し、また、潤滑剤としてステアリン酸カルシウムを磁粉質量に対して0.5質量%添加した。成形圧力は、予備加圧は200MPa、本成形の最終加圧が1000MPaとした。硬化処理は、170℃で2時間加熱後、常温まで30分で冷却した。ボンド磁石部の部分を切出して磁気特性を評価したところ、Br≧0.6T,Hcj≧700kA/mであった。また軟磁性部の部分を切りだし特性評価したところ、Bm≧1.4t,Hc≦800A/mであった。また、磁石部と軟磁性部の界面の引張り強度について、JIS−K7113中の小形試験片の規格に準じる試験片にて測定した結果を表2に示す。
(Example 5)
As the rotor compression molding method, the following three methods were used to examine the compression molding order of the soft magnetic portion and the bond magnet portion. As a binder, epoxy resin was added in an amount of 3% by mass with respect to the magnet powder and 1.1% by mass with respect to the soft magnetic powder.
(1) A binder and a compound mainly composed of magnet powder having an average particle diameter of 50 to 200 μm are pre-formed into a preform, and then a binder and a soft magnetic powder compound having an average particle diameter of 1 to 50 μm are mainly used. A first manufacturing method in which powder is fed into a mold so as to be adjacent to the first preform, and preformed, and then a molding pressure larger than the preforming pressure is applied to perform integral molding.
(2) Molding pressure for molding a preform of a soft magnetic powder compound and a preform of a magnet powder compound, placing the both preforms in combination in a mold, and molding the preform A second manufacturing method in which a larger molding pressure is applied and the main molding is performed and integrated.
(3) A soft magnetic powder compound is preformed into a preform, and then the magnet powder compound is powdered into a mold so as to be adjacent to the first preform, and then preformed. A third manufacturing method in which a molding pressure larger than the pressure is applied to perform integral molding.
A rotor having the same shape as shown in FIG. 1 was manufactured by these three methods, and the pressing force between the soft magnetic part and the bonded magnet part was measured. Soft magnetic powder having an average particle size of 31.2 μm (Sympatec, measured by HEROS RODOS) was used, and magnet powder having an average particle size of 96.9 μm was used. To the magnet powder compound, 3% by mass of thermosetting resin (epoxy resin) as a binder was added based on the mass of magnetic powder, and 0.5% by mass of calcium stearate as a lubricant was added based on the mass of magnetic powder. To the soft magnetic powder compound, 1.1% by mass of thermosetting resin (epoxy resin) as a binder is added based on the mass of the magnetic powder, and 0.5% by mass of calcium stearate as a lubricant is added based on the mass of the magnetic powder. did. The molding pressure was 200 MPa for the pre-pressurization and 1000 MPa for the final pressurization of the main molding. The curing process was performed at 170 ° C. for 2 hours and then cooled to room temperature in 30 minutes. When the bonded magnet portion was cut out and the magnetic characteristics were evaluated, Br ≧ 0.6T and Hcj ≧ 700 kA / m. When the soft magnetic part was cut out and the characteristics were evaluated, Bm ≧ 1.4t and Hc ≦ 800 A / m. In addition, Table 2 shows the results of measuring the tensile strength at the interface between the magnet part and the soft magnetic part with a test piece according to the standard for a small test piece in JIS-K7113.

Figure 2005020991
Figure 2005020991

(実施例6)
図12は、本発明の実施例1による永久磁石回転子を用いた回転機の断面図の一例である。電気伝導率が20kS/m以下の軟磁性材で周囲を取り囲んでいる。
(Example 6)
FIG. 12 is an example of a sectional view of a rotating machine using a permanent magnet rotor according to the first embodiment of the present invention. It is surrounded by a soft magnetic material having an electric conductivity of 20 kS / m or less.

永久磁石回転子は、図2の製造方法を用いて成形した後、ボンド磁石部の厚み方向にほぼ沿うように着磁磁界を印加した。磁石粉末としては等方性のNd-Fe-B系粉末を、軟磁性粉末としては絶縁皮膜でコーテイングした純Fe鉄粉に熱硬化性樹脂を2重量%配合加熱混練し、成形用コンパウンドとした。成形圧力は、予備加圧を200MPa、最終加圧を1000MPaとした。硬化処理は、170℃で2時間加熱後、常温まで30分で冷却した。   The permanent magnet rotor was molded using the manufacturing method of FIG. 2, and then a magnetizing magnetic field was applied so as to be substantially along the thickness direction of the bonded magnet portion. Isotropic Nd-Fe-B powder is used as magnet powder, and 2% by weight of thermosetting resin is mixed and heat-mixed with pure Fe iron powder coated with insulating film as soft magnetic powder to form a molding compound. . The molding pressure was 200 MPa for pre-pressurization and 1000 MPa for final pressurization. The curing process was performed at 170 ° C. for 2 hours and then cooled to room temperature in 30 minutes.

このようにして製造した回転子に回転軸を中心に設け、巻線を施された固定子と組合せて回転トルクを測定した。固定子のスロット数は6であり、固定子コイルの巻線をY結線して120度矩形波通電した。各スロット中を流れるアンペアターン数は300ATとした。また、ボンド磁石部の部分を切出して磁気特性を評価したところ、Br≧0.6T,Hcj≧700kA/mであった。また軟磁性部の部分を切りだし特性評価したところ、Bm≧1.4t,Hc≦800A/mであった。   The rotor manufactured in this manner was provided with a rotating shaft at the center, and the rotational torque was measured in combination with a stator provided with a winding. The number of slots of the stator was 6, and the winding of the stator coil was Y-connected and a 120-degree rectangular wave was energized. The number of ampere turns flowing through each slot was 300 AT. Moreover, when the magnetic characteristics were evaluated by cutting out the bonded magnet portion, it was Br ≧ 0.6T and Hcj ≧ 700 kA / m. When the soft magnetic part was cut out and the characteristics were evaluated, Bm ≧ 1.4t and Hc ≦ 800 A / m.

回転子の角度に対して電流が発生する回転磁界の角度(相対角度)を横軸に、正規化された発生トルクを縦軸に示した測定結果を図13に示す。通常の永久磁石式回転子を用いた場合は、永久磁石の発生する磁界が固定子コイルと鎖交することによって回転トルクを発生するため、トルク発生の中心角度は電気角で90degおよび270degの箇所であるが、本発明の回転子ではリラクタンストルクをも発生するため、最大トルクが120degと300deg付近に移動していることがわかる。   FIG. 13 shows the measurement results in which the horizontal axis represents the angle (relative angle) of the rotating magnetic field that generates current with respect to the rotor angle, and the vertical axis represents the normalized generated torque. When a normal permanent magnet rotor is used, rotational torque is generated when the magnetic field generated by the permanent magnet is linked to the stator coil, so the center angle of torque generation is an electrical angle of 90deg and 270deg. However, since the reluctance torque is also generated in the rotor of the present invention, it can be seen that the maximum torque has moved to around 120 deg and 300 deg.

本発明の製造方法においては、永久磁石の形状の自由度が高い。また、従来の磁石を挿入して接着固定するものでは、ヨークと磁石との間に不要なエアギャップが発生するのに対し、本例ではギャップが生じることがない。永久磁石と軟磁性材とが連続した形状で一体的に形成されるため、橋渡し部分をなくすことができると共に、永久磁石を機械的構造部材としても使用できる。図16に示すような永久磁石からの磁束が極間の回転子ヨーク部での短絡(B2)も防止し、永久磁石の磁束力を無駄なく有効利用することができる。   In the manufacturing method of this invention, the freedom degree of the shape of a permanent magnet is high. Further, in the case where a conventional magnet is inserted and bonded and fixed, an unnecessary air gap is generated between the yoke and the magnet, whereas in this example, no gap is generated. Since the permanent magnet and the soft magnetic material are integrally formed in a continuous shape, the bridging portion can be eliminated and the permanent magnet can be used as a mechanical structural member. The magnetic flux from the permanent magnet as shown in FIG. 16 can also prevent a short circuit (B2) at the rotor yoke portion between the poles, and the magnetic force of the permanent magnet can be effectively used without waste.

本発明の一実施例に関わる永久磁石回転子の模式断面図である。It is a schematic cross section of the permanent magnet rotor in connection with one Example of this invention. 本発明の永久磁石回転子を製造する方法の一実施例を示す斜視図および断面図である。It is the perspective view and sectional drawing which show one Example of the method of manufacturing the permanent magnet rotor of this invention. 本発明の一実施例に関わる永久磁石回転子の模式断面図である。It is a schematic cross section of the permanent magnet rotor in connection with one Example of this invention. 本発明の一実施例に関わる永久磁石回転子の模式断面図である。It is a schematic cross section of the permanent magnet rotor in connection with one Example of this invention. 本発明の一実施例に関わる永久磁石回転子の模式断面図である。It is a schematic cross section of the permanent magnet rotor in connection with one Example of this invention. 露出率と局部の残留応力との関係を示す図である。It is a figure which shows the relationship between an exposure rate and a local residual stress. 最薄部の厚さと局部の残留応力との関係を示す図である。It is a figure which shows the relationship between the thickness of the thinnest part, and the residual stress of a local part. 比較例の永久磁石回転子の模式断面図である。It is a schematic cross section of the permanent magnet rotor of a comparative example. 比較例の永久磁石回転子の模式断面図である。It is a schematic cross section of the permanent magnet rotor of a comparative example. 磁石1極を細分割した場合の実施例を示す概要図である。FIG. 5 is a schematic diagram showing an embodiment in which one magnet pole is subdivided. 本発明の一実施例に関わる永久磁石回転子の模式断面図である。It is a schematic cross section of the permanent magnet rotor in connection with one Example of this invention. 本発明の他の実施例による永久磁石回転子を有する回転機の断面図の一例である。It is an example of sectional drawing of the rotary machine which has a permanent magnet rotor by the other Example of this invention. 本発明の他の実施例による発生トルクの測定結果を示す角度―トルク線図である。It is an angle-torque diagram which shows the measurement result of the generated torque by the other Example of this invention. 本発明の他の一実施例に関わる永久磁石回転子の模式断面図である。It is a schematic cross section of a permanent magnet rotor according to another embodiment of the present invention. 従来の表面磁石型永久磁石モータ用回転子を有する回転機の断面図の一例である(SPM)。It is an example of a sectional view of a rotating machine having a rotor for a conventional surface magnet type permanent magnet motor (SPM). 従来の磁石埋設型永久磁石モータ用回転子を有する回転機の断面図の一例である(IPM)。It is an example of a sectional view of a rotating machine having a conventional rotor for a magnet-embedded permanent magnet motor (IPM).

符号の説明Explanation of symbols

1:ボンド磁石部
2:軟磁性部
3:磁石部成形用パンチ
4:軟磁性部成形用パンチ
5:センターシャフト
6:ダイス
7:軟磁性粉末コンパウンド
8:磁石粉末コンパウンド
9:回転軸
10:回転子
13:固定子
14:エアギャップ
17:固定子コイル
A1〜A5:有効磁束
B1、B2:磁束の短絡
31:永久磁石
32:回転子ヨーク
37:貫通穴
1: Bond magnet part 2: Soft magnetic part 3: Punch for magnet part molding 4: Punch for soft magnetic part molding 5: Center shaft 6: Die 7: Soft magnetic powder compound 8: Magnet powder compound 9: Rotating shaft 10: Rotation Child 13: Stator 14: Air gap 17: Stator coil A1 to A5: Effective magnetic flux B1, B2: Short-circuit of magnetic flux 31: Permanent magnet 32: Rotor yoke 37: Through hole

Claims (11)

結合材および磁石粉末を主とするボンド磁石部と、結合材および軟磁性粉末を主とする軟磁性部とを有し、圧縮成形手段を用いて形成された永久磁石埋設型の回転子であって、前記ボンド磁石部は磁極の両面が前記軟磁性部に埋設されていることを特徴とする回転子。 This is a permanent magnet embedded rotor having a bonded magnet portion mainly composed of a binder and a magnet powder and a soft magnetic portion mainly composed of a binder and a soft magnetic powder and formed using compression molding means. The bonded magnet portion has a magnetic pole embedded in both sides of the soft magnetic portion. 前記回転子は、前記ボンド磁石部の端部が前記回転子の周側上に露出面を有し、この露出面の一箇所あたりの幅が回転子の全周の2%以下(0%を含まず)であることを特徴とする請求項1に記載の回転子。 The rotor has an exposed surface at the end of the bonded magnet portion on the circumferential side of the rotor, and the width of one portion of the exposed surface is 2% or less (0% of the entire circumference of the rotor). The rotor according to claim 1, wherein the rotor is not included. 前記回転子は、断面内部にボンド磁石部の全体が埋設されるように形成され、かつ前記回転子の前記ボンド磁石部と前記周側面の間の最薄部が0.3mm以上1.5mm以内であることを特徴とする請求項1に記載の回転子。 The rotor is formed so that the entire bonded magnet portion is embedded in the cross section, and the thinnest portion between the bonded magnet portion and the peripheral side surface of the rotor is 0.3 mm or more and 1.5 mm or less. The rotor according to claim 1, wherein 前記ボンド磁石部は回転子中心側に膨らむアーク形状であり、回転子が4〜12極の磁極部を有するように形成されていることを特徴とする請求項2または3に記載の回転子。 4. The rotor according to claim 2, wherein the bonded magnet portion has an arc shape that swells toward the rotor center side, and the rotor is formed to have a magnetic pole portion having 4 to 12 poles. 5. 前記ボンド磁石部は回転子中心側に膨らむアーク形状が端部で連なって環状をなし、回転子が4〜12極の磁極部を有するように形成されていることを特徴とする請求項2または3に記載の回転子。 3. The bonded magnet portion according to claim 2, wherein an arc shape that swells toward the center of the rotor forms an annular shape connected at the end, and the rotor has a magnetic pole portion having 4 to 12 poles. The rotor according to 3. 前記磁石粉末の平均粒径が50〜200μmであり、前記軟磁性粉末の平均粒径が1〜50μmである請求項1〜5に記載の回転子。 The rotor according to claim 1, wherein the magnet powder has an average particle size of 50 to 200 μm, and the soft magnetic powder has an average particle size of 1 to 50 μm. 前記軟磁性部の電気伝導率は20kS/m以下であり、かつBm≧1.4T、Hc≦800A/mであることを特徴とする請求項1〜3のいずれかに記載の回転子。 4. The rotor according to claim 1, wherein the soft magnetic part has an electric conductivity of 20 kS / m or less, Bm ≧ 1.4 T, and Hc ≦ 800 A / m. 前記ボンド磁石部がBr≧0.4T、Hcj≧600kA/mの圧縮成型磁石部であることを特徴とする請求項1または2に記載の回転子。 3. The rotor according to claim 1, wherein the bonded magnet portion is a compression-molded magnet portion having Br ≧ 0.4T and Hcj ≧ 600 kA / m. 前記ボンド磁石部と前記軟磁性部とのせん断強度が10MPa以上であることを特徴とする請求項1または2に記載の回転子。 The rotor according to claim 1 or 2, wherein a shear strength between the bonded magnet portion and the soft magnetic portion is 10 MPa or more. ボンド磁石部と軟磁性部からなる回転子の製造方法であって、前記ボンド磁石部を結合材および平均粒径が50〜200μmの磁石粉末を主とする磁石粉末コンパウンドにより予備成形し、その後、前記軟磁性部を結合材および平均粒径が1〜50μmの軟磁性粉末を主とする軟磁性粉末コンパウンドにより前記ボンド磁石部に接触するように予備成形し、その後前記ボンド磁石部と軟磁性部を予備成形の圧力よりも高い圧力で本成形して一体にし、その後熱硬化させることを特徴とする回転子の製造方法。 A method of manufacturing a rotor comprising a bonded magnet part and a soft magnetic part, wherein the bonded magnet part is preformed with a binder and a magnet powder compound mainly composed of a magnetic powder having an average particle size of 50 to 200 μm, and thereafter The soft magnetic part is preformed to come into contact with the bond magnet part by a soft magnetic powder compound mainly composed of a binder and a soft magnetic powder having an average particle diameter of 1 to 50 μm, and then the bond magnet part and the soft magnetic part A method for producing a rotor, wherein the main body is integrally molded at a pressure higher than the pressure of the preforming, and then is integrally cured. ボンド磁石部と軟磁性部からなる回転子の製造方法であって、前記ボンド磁石部を結合材および平均粒径が50〜200μmの磁石粉末を主とする磁石粉末コンパウンドにより予備成形し、前記軟磁性部を結合材および平均粒径が1〜50μmの軟磁性粉末を主とする軟磁性粉末コンパウンドにより別途予備成形し、両予備成形体を組合せ予備成形の圧力よりも高い圧力で本成形して一体にし、その後熱硬化させることを特徴とする回転子の製造方法。
A method of manufacturing a rotor comprising a bonded magnet portion and a soft magnetic portion, wherein the bonded magnet portion is preformed with a binder and a magnetic powder compound mainly composed of magnet powder having an average particle size of 50 to 200 μm, The magnetic part is separately preformed with a soft magnetic powder compound mainly composed of a binder and a soft magnetic powder having an average particle diameter of 1 to 50 μm, and both preforms are subjected to main molding at a pressure higher than the pressure of the combined preforming. A method for manufacturing a rotor, characterized in that the rotor is integrally cured and then thermally cured.
JP2004112150A 2003-06-04 2004-04-06 Rotor and manufacturing method therefor Pending JP2005020991A (en)

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PCT/JP2004/018221 WO2005101614A1 (en) 2004-04-06 2004-12-07 Rotor and process for manufacturing the same
EP04821898A EP1734637A4 (en) 2004-04-06 2004-12-07 Rotor and process for manufacturing the same
CN2004800057377A CN1757148B (en) 2004-04-06 2004-12-07 Rotor and process for manufacturing the same
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