JP2010183692A - Magnet for motor, rotor for ipm motor, and ipm motor - Google Patents

Magnet for motor, rotor for ipm motor, and ipm motor Download PDF

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JP2010183692A
JP2010183692A JP2009023557A JP2009023557A JP2010183692A JP 2010183692 A JP2010183692 A JP 2010183692A JP 2009023557 A JP2009023557 A JP 2009023557A JP 2009023557 A JP2009023557 A JP 2009023557A JP 2010183692 A JP2010183692 A JP 2010183692A
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magnet
motor
rotor
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oxide film
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Makoto Kitahara
誠 北原
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Toyota Motor Corp
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnet for a motor which does not increase the number of manufacturing processes, does not rise the manufacturing cost, and ensures high insulation performance between divided magnets, in the magnet for the motor composed of divided magnets, and to provide a rotor for an IPM motor embedded with the magnet for the motor, and the IPM motor equipped with the rotor. <P>SOLUTION: The magnet 10 for the motor is inserted into a slot formed in a direction along a rotor shaft, the magnet 10 is formed by laminating a plurality of divided magnets 3, ..., in the rotor axial direction, and oxidized membranes 2, ..., formed by the oxidization of divided magnets 1, ..., are formed around the divided magnets 3, ..., respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、モータ用磁石と、この磁石が埋め込まれてなるIPMモータ用のロータと、該ロータを備えたIPMモータに関するものである。   The present invention relates to a motor magnet, a rotor for an IPM motor in which the magnet is embedded, and an IPM motor including the rotor.

ブラシレスDCモータをはじめとする各種モータの中で、ロータコア内部に複数の永久磁石が埋め込まれてなる永久磁石埋込型のロータを具備するモータ(以下、IPMモータという)はよく知られるところである。例えば、ハイブリット車両の駆動用モータには、上記するIPMモータが使用されている。   Among various motors including a brushless DC motor, a motor (hereinafter referred to as an IPM motor) including a permanent magnet embedded rotor in which a plurality of permanent magnets are embedded in a rotor core is well known. For example, the above-described IPM motor is used as a drive motor for a hybrid vehicle.

ところで、ステータティースには巻線が集中巻き若しくは分布巻きされることによってコイルが形成されており、コイルに電流を通電することによって磁束を生じさせ、永久磁石による磁束との間でマグネットトルクおよびリラクタンストルクを発生させている。この分布巻きコイルの場合には、集中巻きコイルの場合に比して磁極数も多くなり、したがって、ロータ回転時にティース側からロータの永久磁石に入ってくる磁束(または磁束の変化)は相対的に連続性がある。そのため、ロータ回転時の磁束密度の変化は相対的に少ない。それに対し、集中巻きコイルの場合には、磁束密度の変化が相対的に大きくなることから永久磁石には渦電流が生じ易く、渦電流の発生によって永久磁石は発熱し、不可逆な熱減磁が招来されることで永久磁石自体の磁気特性が低下することとなる。   By the way, a coil is formed in the stator teeth by concentrated winding or distributed winding, and a magnetic flux is generated by passing a current through the coil to generate a magnetic torque and a reluctance between the permanent magnet and the magnetic flux. Torque is generated. In the case of this distributed winding coil, the number of magnetic poles is larger than in the case of the concentrated winding coil. Therefore, the magnetic flux (or change in magnetic flux) that enters the permanent magnet of the rotor from the teeth side when the rotor rotates is relative. Has continuity. Therefore, the change of the magnetic flux density at the time of rotor rotation is relatively small. On the other hand, in the case of concentrated winding coils, the change in magnetic flux density is relatively large, so eddy currents are likely to be generated in the permanent magnets. The generation of eddy currents causes the permanent magnets to generate heat, and irreversible thermal demagnetization occurs. Inviting the magnetic properties of the permanent magnet itself will be reduced.

近時のハイブリッド自動車や電気自動車で使用される駆動用モータに関して言えば、モータの出力性能アップが追求されている中でたとえばその回転数や極数の増加が図られており、この回転数の増加等によって磁石に作用する磁界の変動率が大きくなり、その結果として上記渦電流が発生し易く、発熱によって齎される磁石の熱減磁によってモータ性能が逆に低下し、モータの耐久性の低下に繋がるといった課題が生じている。   Speaking of drive motors used in recent hybrid vehicles and electric vehicles, for example, the number of revolutions and the number of poles have been increased while the improvement in motor output performance has been pursued. As a result, the fluctuation rate of the magnetic field acting on the magnet increases due to an increase, and as a result, the eddy current is likely to be generated. The problem that it leads to is generated.

上記する渦電流の発生およびそれに起因する熱減磁の招来を防止するために、IPMモータにおいては、該永久磁石を複数の分割磁石から形成しておき、この分割磁石を束ねてロータスロットに挿入設置する方策が講じられている。   In order to prevent the generation of the eddy current and the induction of thermal demagnetization due to the above, in the IPM motor, the permanent magnet is formed from a plurality of divided magnets, and the divided magnets are bundled and inserted into the rotor slot. Measures to install are taken.

ここで、上記する分割磁石からなるモータ用磁石(永久磁石)の製造方法に関する技術として特許文献1を挙げることができる。この永久磁石は、永久磁石母材を分割する第1工程と、分割して得られた磁石片の全面を絶縁皮膜処理する第2工程と、絶縁皮膜処理が施された磁石片を接合する第3工程と、接合体が所定の寸法となるよう加工する第4工程と、加工後の接合体の全面に絶縁皮膜処理を施す第5工程と、を含む工程によって製造されるものである。   Here, patent document 1 can be mentioned as a technique regarding the manufacturing method of the magnet for motors (permanent magnet) which consists of an above-mentioned division | segmentation magnet. The permanent magnet includes a first step of dividing the permanent magnet base material, a second step of treating the whole surface of the magnet piece obtained by the division with an insulating film, and a second step of joining the magnet piece subjected to the insulating film treatment. It is manufactured by a process including three processes, a fourth process in which the bonded body is processed to have a predetermined size, and a fifth process in which an insulating film treatment is performed on the entire surface of the bonded body after processing.

特開2003−134750号公報JP 2003-134750 A

特許文献1に開示の製造方法によれば、第2工程にて分割磁石片の周囲に、第5工程にて永久磁石の周囲にそれぞれエポキシ樹脂やエナメル樹脂等からなる絶縁皮膜が施されることで、分割磁石片同士を接着剤等で接着する場合に、この接着剤層が仮に不均一であっても、分割磁石片同士が直接接触することを抑止することができる、というものである。しかし、2つの工程のそれぞれで樹脂皮膜を形成することから、製造工数の増加、製造効率性の低下、製造コストの高騰は否めない。   According to the manufacturing method disclosed in Patent Document 1, an insulating film made of an epoxy resin, an enamel resin, or the like is applied around the split magnet piece in the second step and around the permanent magnet in the fifth step. Thus, when the divided magnet pieces are bonded to each other with an adhesive or the like, even if the adhesive layer is non-uniform, it is possible to prevent the divided magnet pieces from directly contacting each other. However, since the resin film is formed in each of the two steps, it cannot be denied that the number of manufacturing steps increases, the manufacturing efficiency decreases, and the manufacturing cost increases.

本発明は、上記する問題に鑑みてなされたものであり、分割磁石からなるモータ用磁石において、製造工数を増加させることなく、製造コストを高騰させることなく、しかも分割磁石間の絶縁性に優れたモータ用磁石と、このモータ用磁石を埋設してなるIPMモータ用ロータ、このロータを具備するIPMモータを提供することを目的とする。   The present invention has been made in view of the above problems, and in a magnet for a motor composed of split magnets, without increasing the number of manufacturing steps, without increasing the manufacturing cost, and excellent in insulation between the split magnets. An object of the present invention is to provide a motor magnet, an IPM motor rotor in which the motor magnet is embedded, and an IPM motor including the rotor.

前記目的を達成すべく、本発明によるモータ用磁石は、ロータ軸に沿う方向に設けられたスロット内に挿入されるモータ用磁石であって、前記磁石は、複数の分割磁石が前記ロータ軸方向に積層されて形成されており、各分割磁石の周りには、分割磁石が酸化してなる酸化皮膜が形成されているものである。   In order to achieve the above object, a motor magnet according to the present invention is a motor magnet inserted into a slot provided in a direction along the rotor axis, and the magnet includes a plurality of divided magnets in the rotor axis direction. Each of the divided magnets is formed with an oxide film formed by oxidizing the divided magnets.

本発明の磁石は、永久磁石をその主な対象としており、希土類磁石やフェライト磁石、アルニコ磁石等を包含するものであり、希土類磁石としては、ネオジムに鉄とボロンを加えた3成分系のネオジム磁石、サマリウムとコバルトとの2成分系の合金からなるサマリウムコバルト磁石、サマリウム鉄窒素磁石、プラセオジム磁石などを挙げることができる。中でも、希土類磁石はフェライト磁石やアルニコ磁石に比して最大エネルギー積(BH)maxが高いことから、高出力が要求されるハイブリッド車等の駆動用モータへの適用に好適である。 The magnets of the present invention are mainly permanent magnets, and include rare earth magnets, ferrite magnets, alnico magnets, etc. As rare earth magnets, ternary neodymium in which iron and boron are added to neodymium. Examples thereof include a magnet, a samarium cobalt magnet composed of a binary alloy of samarium and cobalt, a samarium iron nitrogen magnet, and a praseodymium magnet. Among these, rare earth magnets have a maximum energy product (BH) max higher than that of ferrite magnets or alnico magnets, and therefore are suitable for application to drive motors such as hybrid vehicles that require high output.

本発明の磁石を構成する分割磁石は、その表面に磁石成分が酸化してなる酸化皮膜を有し、この酸化皮膜で隣接する分割磁石との絶縁を補償するものであり、既述する従来技術のごとく、磁石とは別素材の樹脂皮膜等を形成するものではない。   The divided magnet constituting the magnet of the present invention has an oxide film formed by oxidizing a magnet component on its surface, and this oxide film compensates the insulation with the adjacent divided magnet. As described above, a resin film or the like made of a material different from the magnet is not formed.

ここで、本発明者等の解析および実験によれば、分割磁石表面に形成される酸化皮膜の厚みは、略15nmか、15nm以上の厚みを有するのが好ましいという知見が得られている。これは、磁石に生じる渦電流損失に相間する磁石抵抗に関し、無垢の磁石に比して分割磁石とすることで磁石抵抗は低減すること、何等の絶縁皮膜を具備しない分割磁石からなる磁石に対して酸化皮膜を具備する分割磁石からなる磁石の磁石抵抗はその酸化皮膜の厚みによって変化し、15nm付近で磁石抵抗の低減率の変曲点が確認され、略15nmの厚みで該低減率がサチュレートすること、という理由によるものである。   Here, according to the analysis and experiment by the present inventors, it has been found that the thickness of the oxide film formed on the surface of the divided magnet is preferably about 15 nm or more than 15 nm. This is related to the magnet resistance interrelated to the eddy current loss that occurs in the magnet, by reducing the magnet resistance by using a split magnet compared to a solid magnet, and for a magnet composed of a split magnet without any insulating film. The magnet resistance of a magnet composed of a split magnet having an oxide film varies depending on the thickness of the oxide film, and an inflection point of the reduction ratio of the magnet resistance is confirmed near 15 nm, and the reduction ratio is saturated at a thickness of approximately 15 nm. It is because of doing.

さらに、本発明者等によれば、15nm程度の酸化皮膜を形成するには、分割磁石をおよそ2日間程度放置するだけでよいことが確認されている。   Furthermore, according to the present inventors, it has been confirmed that to form an oxide film of about 15 nm, it is only necessary to leave the divided magnets for about two days.

上記する本発明の磁石(たとえば永久磁石)がロータ軸に沿う方向に設けられたスロット内に埋設されてなる、IPMモータ用ロータ、このロータと、その周囲に配設されるステータを具備するIPMモータは、近時その量産が盛んになっており、かつ高い出力性能が期待されるハイブリッド自動車や電気自動車の駆動用モータに好適である。なお、これらのロータ(コア)やステータ(コア)は、電磁鋼板を積層してなる鋼板積層体のほか、鉄、鉄−シリコン系合金、鉄−窒素系合金、鉄−ニッケル系合金、鉄−炭素系合金、鉄−ホウ素系合金、鉄−コバルト系合金、鉄−リン系合金、鉄−ニッケル−コバルト系合金および鉄−アルミニウム−シリコン系合金などの軟磁性金属粉末、もしくは軟磁性金属酸化物粉末がシリコーン樹脂等の樹脂バインダーで被覆された磁性粉末などからなる圧粉磁心、高密度圧粉磁心(HDMC)などから成形できる。   An IPM having a rotor for an IPM motor, in which a magnet (for example, a permanent magnet) of the present invention described above is embedded in a slot provided in a direction along the rotor axis, and a rotor disposed around the rotor. The motor has recently been mass-produced and is suitable for a drive motor for a hybrid vehicle or an electric vehicle that is expected to have high output performance. These rotors (cores) and stators (cores) are not only steel sheet laminates made by laminating electromagnetic steel sheets, but also iron, iron-silicon alloys, iron-nitrogen alloys, iron-nickel alloys, iron- Soft magnetic metal powders such as carbon alloys, iron-boron alloys, iron-cobalt alloys, iron-phosphorus alloys, iron-nickel-cobalt alloys and iron-aluminum-silicon alloys, or soft magnetic metal oxides The powder can be molded from a powder magnetic core made of a magnetic powder coated with a resin binder such as a silicone resin, a high-density powder magnetic core (HDMC), or the like.

以上の説明から理解できるように、本発明のモータ用磁石と、これを具備するIPMモータ用ロータおよびIPMモータによれば、単に分割磁石を所定期間放置し、その表面に酸化皮膜が形成されたものを積層して形成された磁石をロータ内に埋設するだけの、極めて簡易で、かつコスト増を招来しない製造方法により、磁石内で生じ得る渦電流損失を大幅に低減でき、もって、回転性能、トルク性能、回転効率に優れたIPMモータを得ることができる。   As can be understood from the above description, according to the motor magnet of the present invention, and the rotor and IPM motor having the same, the split magnet was simply left for a predetermined period, and an oxide film was formed on the surface thereof. An extremely simple manufacturing method that embeds magnets formed by stacking objects in a rotor and does not cause an increase in cost can significantly reduce eddy current loss that can occur in magnets. An IPM motor having excellent torque performance and rotational efficiency can be obtained.

(a)は、本発明の磁石を構成する分割磁石の製造方法を示した模式図であり、(b)は、図1aで製造された分割磁石を積層してなる本発明の磁石を示した模式図である。(A) is the schematic diagram which showed the manufacturing method of the split magnet which comprises the magnet of this invention, (b) showed the magnet of this invention formed by laminating | stacking the split magnet manufactured by FIG. 1a. It is a schematic diagram. 図1の磁石がロータ内に埋設されたIPMモータの斜視図である。FIG. 2 is a perspective view of an IPM motor in which the magnet of FIG. 1 is embedded in a rotor. 酸化皮膜の厚みの異なる分割磁石からなる磁石の、酸化皮膜のない従来構造の分割磁石からなる磁石に対する磁石抵抗低減率に関する、解析結果および実験結果を示したグラフである。It is the graph which showed the analysis result and the experimental result regarding the magnet resistance reduction rate with respect to the magnet which consists of a split magnet of the conventional structure without an oxide film of the magnet which consists of a split magnet from which the thickness of an oxide film differs.

以下、図面を参照して本発明の実施の形態を説明する。なお、図示するIPMモータにおいて、ティース周りに形成されるコイルや、コイルボビン、相間絶縁紙などの図示は省略している。また、図示のごとく円環状に一体に形成されたステータ以外にも、平面視が弧状のヨークと、ヨークから径方向内側に突出するティースと、からなる電磁鋼板が積層されてなる分割コアが円周方向に組み付けられ、その外周が筒体にて締結されてなる分割ステータであってもよい。   Embodiments of the present invention will be described below with reference to the drawings. In the illustrated IPM motor, illustration of coils formed around the teeth, coil bobbins, interphase insulating paper, and the like is omitted. In addition to the stator integrally formed in an annular shape as shown in the figure, a divided core formed by laminating electromagnetic steel plates made of an arc-shaped yoke in plan view and teeth projecting radially inward from the yoke is a circle. It may be a divided stator that is assembled in the circumferential direction and the outer periphery thereof is fastened by a cylindrical body.

図1は、本発明の磁石を構成する分割磁石の製造方法を示した模式図である。その図1aで示すように、挿入されるロータの磁石スロットの長さに応じた磁石(永久磁石)を所定数だけ分割してなる分割磁石1を用意し、これを、たとえば、室温25℃程度、室内の相対湿度が50%RH程度の雰囲気下で、たとえば2〜3日間、この分割磁石1を放置する。なお、この分割磁石1は、希土類磁石やフェライト磁石、アルニコ磁石等であり、希土類磁石としては、ネオジムに鉄とボロンを加えた3成分系のネオジム磁石、サマリウムとコバルトとの2成分系の合金からなるサマリウムコバルト磁石、サマリウム鉄窒素磁石、プラセオジム磁石などである。   FIG. 1 is a schematic view showing a method for manufacturing a segmented magnet constituting the magnet of the present invention. As shown in FIG. 1a, a split magnet 1 is prepared by splitting a predetermined number of magnets (permanent magnets) according to the length of the magnet slot of the rotor to be inserted. The split magnet 1 is left in an atmosphere having an indoor relative humidity of about 50% RH, for example, for 2 to 3 days. The split magnet 1 is a rare earth magnet, a ferrite magnet, an alnico magnet, or the like. As the rare earth magnet, a ternary neodymium magnet obtained by adding iron and boron to neodymium, or a binary alloy of samarium and cobalt. Samarium cobalt magnet, samarium iron nitrogen magnet, praseodymium magnet and the like.

放置後の分割磁石1の周囲には、その表面の磁石成分が酸化して酸化皮膜2が形成されて、ロータ内に挿入される分割磁石3が得られる。なお、2日間程度の放置により、およそ15nm程度の厚みの酸化皮膜2が形成される。   The magnet component on the surface is oxidized around the divided magnet 1 after being left to form an oxide film 2 to obtain the divided magnet 3 to be inserted into the rotor. The oxide film 2 having a thickness of about 15 nm is formed by being left for about 2 days.

形成された分割磁石3を所定数積層して磁石10を製造し、この磁石3を不図示のロータに開設された磁石用スロット内に挿入する(X方向)。なお、隣接する分割磁石3,3同士は、耐熱性の接着剤にて接着されてもよいし、無接着のまま積層姿勢でスロット内に挿入されてもよい。   A magnet 10 is manufactured by laminating a predetermined number of the formed divided magnets 3, and this magnet 3 is inserted into a magnet slot provided in a rotor (not shown) (X direction). The adjacent divided magnets 3 and 3 may be bonded with a heat-resistant adhesive, or may be inserted into the slot in a stacked posture without bonding.

図2は、磁石がロータ内に埋設されたIPMモータを斜視図で示したものである。
図2で示すIPMモータ100は、平面視が略環状のヨーク52と、該ヨーク52から径方向内側に突出するティース51と、からなり、電磁鋼板5,…が積層されて形成されているステータ50と、ステータ50の内側に回転自在に配設され、円盤状の電磁鋼板4,…が積層されてなるロータ40と、から大略構成されている。このロータ40には、その中央位置においてロータ軸41(駆動シャフトスロット)が開設されており、その周縁部には、所定数で該ロータ軸41に沿う方向に延びる磁石用スロットが開設されており、この磁石用スロットに磁石10が挿入され、たとえば該スロットと永久磁石10の間に固定用樹脂が充填されて磁石10のスロット内固定が補償されている。なお、図示例は、一極当たり一個の磁石10が、平面視でその長手方向をティース51に正対させた姿勢で配設された形態であるが、これ以外にも、2つの永久磁石で一極を形成するものであって、これらの永久磁石が平面視でV字状に配置された形態であってもよい。
FIG. 2 is a perspective view showing an IPM motor in which a magnet is embedded in a rotor.
An IPM motor 100 shown in FIG. 2 includes a yoke 52 having a substantially annular shape in plan view and teeth 51 protruding radially inward from the yoke 52, and is formed by laminating electromagnetic steel plates 5,. 50 and a rotor 40 that is rotatably arranged inside the stator 50 and is formed by laminating disk-shaped electromagnetic steel plates 4... The rotor 40 is provided with a rotor shaft 41 (drive shaft slot) at a central position thereof, and a magnet slot extending in a direction along the rotor shaft 41 in a predetermined number is provided at a peripheral portion thereof. The magnet 10 is inserted into the magnet slot and, for example, a fixing resin is filled between the slot and the permanent magnet 10 to compensate for the fixing of the magnet 10 in the slot. In the illustrated example, one magnet 10 per pole is arranged in a posture in which the longitudinal direction thereof is directly opposed to the teeth 51 in a plan view, but in addition to this, two permanent magnets are used. One pole may be formed, and these permanent magnets may be arranged in a V shape in plan view.

ステータ50は、たとえば、そのヨーク52でかしめられて積層された電磁鋼板5,…が一体に形成されており、ロータ40も、磁石10とロータ軸41の間の領域でかしめられて電磁鋼板4,…が一体に形成されている。   The stator 50 is formed integrally with, for example, electromagnetic steel plates 5, which are caulked and laminated by a yoke 52, and the rotor 40 is also caulked in an area between the magnet 10 and the rotor shaft 41. Are integrally formed.

なお、ステータ50、ロータ40ともに、電磁鋼板を積層した形態以外にも、鉄、鉄−シリコン系合金、鉄−窒素系合金、鉄−ニッケル系合金、鉄−炭素系合金、鉄−ホウ素系合金、鉄−コバルト系合金、鉄−リン系合金、鉄−ニッケル−コバルト系合金および鉄−アルミニウム−シリコン系合金などの軟磁性金属粉末、もしくは軟磁性金属酸化物粉末がシリコーン樹脂等の樹脂バインダーで被覆された磁性粉末などからなる圧粉磁心にて成形されるものであってもよい。   It should be noted that both the stator 50 and the rotor 40 are in the form of laminated magnetic steel sheets, iron, iron-silicon alloy, iron-nitrogen alloy, iron-nickel alloy, iron-carbon alloy, iron-boron alloy. Soft magnetic metal powder such as iron-cobalt alloy, iron-phosphorus alloy, iron-nickel-cobalt alloy and iron-aluminum-silicon alloy, or soft magnetic metal oxide powder is a resin binder such as silicone resin. It may be formed of a powder magnetic core made of coated magnetic powder or the like.

図示するIPMモータ100は、そのロータ40内において、酸化皮膜2にて相互に絶縁された分割磁石3,…が積層されてなる磁石10が所定の磁極数挿入されていることにより、磁石10内に生じ得る渦電流損失(もしくはこれに相間する磁石抵抗)を可及的に低減することができ、これに起因して、トルク性能、回転性能、回転効率に優れたモータとなる。   The illustrated IPM motor 100 includes a magnet 10 in which a predetermined number of magnetic poles are inserted in a rotor 40 in which divided magnets 3,... Insulated from each other by an oxide film 2 are laminated. Eddy current loss (or magnet resistance between them) can be reduced as much as possible, resulting in a motor having excellent torque performance, rotational performance, and rotational efficiency.

[酸化皮膜の厚みの異なる分割磁石からなる磁石の、酸化皮膜のない従来構造の分割磁石からなる磁石に対する磁石抵抗低減率に関する、解析および実験とそれらの結果]
本発明者等は、図1bで示す磁石を製造し、電磁鋼板が積層してなるコアにコイルを形成した磁場形成装置を用意し、このコイルに電流を通電して磁界を形成し、この磁界内に磁石を載置して、磁石抵抗を計測する実験をおこなった。
[Analysis, experiment, and results of the magnet resistance reduction ratio of magnets made of split magnets with different thicknesses of oxide film compared to magnets made of split magnets of conventional structure without oxide film]
The inventors of the present invention manufactured a magnet shown in FIG. 1b, prepared a magnetic field forming device in which a coil was formed on a core formed by laminating electromagnetic steel sheets, and formed a magnetic field by passing a current through the coil. An experiment was conducted in which the magnet resistance was measured by placing a magnet inside.

この実験では、磁石を15の分割磁石から形成し、酸化皮膜の厚みがゼロのもの(すなわち、従来の酸化皮膜なしの分割磁石)から、厚みが15nm程度のもの、40nm程度のものを作成した。さらに、分割磁石の寸法は、図1aを参照して、t1が3.8mm、t2が6.5mm、t3が9.9mmである。ここで、酸化皮膜の厚みの測定は、XPS(X線光電子分光分析)にておこなった。   In this experiment, the magnet was formed of 15 divided magnets, and those having a thickness of about 15 nm or about 40 nm were prepared from those having a thickness of zero oxide film (that is, a conventional divided magnet without an oxide film). . Further, the dimensions of the divided magnets are as follows: t1 is 3.8 mm, t2 is 6.5 mm, and t3 is 9.9 mm. Here, the thickness of the oxide film was measured by XPS (X-ray photoelectron spectroscopy).

また、この実験に先立ち、実験と同素材の電磁鋼板の磁気特性を有するコアモデル、同素材の磁石モデル、同様の通電条件をコンピュータ内で設定し、磁石抵抗を解析で求めた。解析結果、実験結果を図3に示している。   Prior to this experiment, the core model having the magnetic properties of the magnetic steel sheet of the same material as the experiment, the magnet model of the same material, and the same energization conditions were set in the computer, and the magnet resistance was obtained by analysis. The analysis results and experimental results are shown in FIG.

図3において、磁石抵抗:1.0×10−4は酸化皮膜の厚みが15nmに対応しており、磁石抵抗:1.0×1012は酸化皮膜の厚みが30nmに、磁石抵抗:1.0×1016は酸化皮膜の厚みが40nmにそれぞれ対応している。また、抵抗低減率(%)は、酸化皮膜のない従来構造の分割磁石からなる磁石の抵抗値に対して、それぞれの厚みの酸化皮膜を具備する分割磁石からなる磁石の抵抗値の低減割合である。 In FIG. 3, magnet resistance: 1.0 × 10 −4 corresponds to an oxide film thickness of 15 nm, magnet resistance: 1.0 × 10 12 has an oxide film thickness of 30 nm, and magnet resistance: 1. 0 × 10 16 corresponds to an oxide film thickness of 40 nm. Also, the resistance reduction rate (%) is the ratio of reduction of the resistance value of a magnet composed of a segmented magnet having an oxide film of each thickness with respect to the resistance value of a segmented magnet having a conventional structure without an oxide film. is there.

図3より、実験結果(実験値が○で、○同士を繋ぐ実線ライン)と、解析結果(解析値が×で、×同士を繋ぐ点線ライン)は、ほぼ完全に相間している結果となっている。
また、実験結果、解析結果ともに、酸化皮膜が15nm付近までは比例的に抵抗低減率が増加し、15nm付近で抵抗低減率の変曲点を迎え、15nm以上の範囲では抵抗低減率が70%程度にサチュレートしているという結果となった。
From FIG. 3, the experimental result (the experimental value is ○, a solid line connecting the ○) and the analysis result (the analytical value is ×, the dotted line connecting the ×) are almost completely in phase with each other. ing.
In addition, in both the experimental results and the analysis results, the resistance reduction rate increases proportionally until the oxide film is near 15 nm, the resistance reduction rate reaches an inflection point near 15 nm, and the resistance reduction rate is 70% in the range of 15 nm or more. The result was that it was saturating to the extent.

したがって、酸化皮膜の厚みが15nm程度の分割磁石からなる磁石を製造することにより、可及的に磁石体格を小さくしながら、磁石抵抗(渦電流損失)の可及的に少ない磁石が得られることが実証された。   Therefore, by producing a magnet composed of a split magnet having an oxide film thickness of about 15 nm, a magnet with as little magnet resistance (eddy current loss) as possible can be obtained while making the magnet size as small as possible. Has been demonstrated.

なお、本発明者等の知見によれば、磁石の分割数を変化させることにより、抵抗低減率は70%を高低するが(分割数が15よりも多くなると、70%以上の抵抗低減率になるという傾向)、酸化皮膜の厚みが15nm付近で変曲点を向かえ、抵抗低減率がサチュレートする傾向に変化がないことは特定されている。   According to the knowledge of the present inventors, the resistance reduction rate increases or decreases by 70% by changing the number of magnet divisions (when the number of divisions exceeds 15, the resistance reduction rate becomes 70% or more. It has been specified that there is no change in the tendency of the resistance reduction rate to saturate when the thickness of the oxide film reaches the inflection point in the vicinity of 15 nm.

上記する分割磁石3を積層してなる磁石10をロータ内に具備してなるIPMモータ100は、埋設される分割磁石3が、単に放置されて、その表面に所定厚の酸化皮膜が形成されるという、極めて簡易で何等のコスト増を齎さない方法で製造されるものであり、しかも磁石抵抗の極めて少ない磁石であることから、簡易で安価な製造方法により、トルク性能、回転性能、モータ効率に優れたIPMモータである。したがって、このようなIPMモータは、車載機器に高い性能を要求する近時のハイブリッド自動車や電気自動車の駆動用モータに好適である。   In the IPM motor 100 in which the magnet 10 formed by laminating the divided magnets 3 described above is provided in the rotor, the embedded divided magnets 3 are simply left and an oxide film having a predetermined thickness is formed on the surface thereof. Because it is a magnet that is extremely simple and does not add any cost, and because it is a magnet with extremely low magnet resistance, it is possible to achieve torque performance, rotational performance, and motor efficiency with a simple and inexpensive manufacturing method. It is an excellent IPM motor. Therefore, such an IPM motor is suitable for a drive motor for a recent hybrid vehicle or electric vehicle that requires high performance from the in-vehicle device.

以上、本発明の実施の形態を図面を用いて詳述してきたが、具体的な構成はこの実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲における設計変更等があっても、それらは本発明に含まれるものである。   The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

1…分割磁石、2…酸化皮膜、3…分割磁石、4,5…電磁鋼板、10…磁石(永久磁石)、40…ロータ、41…ロータ軸(回転軸)、50…ステータ、100…IPMモータ   DESCRIPTION OF SYMBOLS 1 ... Split magnet, 2 ... Oxide film, 3 ... Split magnet, 4, 5 ... Electromagnetic steel plate, 10 ... Magnet (permanent magnet), 40 ... Rotor, 41 ... Rotor shaft (rotary shaft), 50 ... Stator, 100 ... IPM motor

Claims (4)

ロータ軸に沿う方向に設けられたスロット内に挿入されるモータ用磁石であって、
前記磁石は、複数の分割磁石が前記ロータ軸方向に積層されて形成されており、
各分割磁石の周りには、分割磁石が酸化してなる酸化皮膜が形成されている、モータ用磁石。
A motor magnet inserted into a slot provided in a direction along the rotor axis,
The magnet is formed by laminating a plurality of divided magnets in the rotor axial direction,
A motor magnet having an oxide film formed by oxidizing the divided magnets around each divided magnet.
前記酸化皮膜の厚みは、略15nmもしくは、15nm以上である、請求項1に記載のモータ用磁石。   The motor magnet according to claim 1, wherein a thickness of the oxide film is approximately 15 nm or 15 nm or more. ロータ軸に沿う方向に設けられたスロット内に請求項1または2に記載のモータ用磁石が埋設されてなる、IPMモータ用ロータ。   A rotor for an IPM motor, wherein the motor magnet according to claim 1 is embedded in a slot provided in a direction along the rotor axis. 請求項3に記載のロータを少なくとも備えている、IPMモータ。   An IPM motor comprising at least the rotor according to claim 3.
JP2009023557A 2009-02-04 2009-02-04 Magnet for motor, rotor for ipm motor, and ipm motor Pending JP2010183692A (en)

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