JP4396960B2

JP4396960B2 - Permanent magnet abduction type rotating electrical machine

Info

Publication number: JP4396960B2
Application number: JP2002274808A
Authority: JP
Inventors: 正文坂本
Original assignee: Nidec Servo Corp
Current assignee: Nidec Servo Corp
Priority date: 2002-09-20
Filing date: 2002-09-20
Publication date: 2010-01-13
Anticipated expiration: 2022-09-20
Also published as: JP2004112969A

Description

【０００１】
【産業上の利用分野】
本発明は、複写機の転写ドラム等駆動に適した外転型回転電機に関する。
【０００２】
【従来の技術】
複写機の転写ドラムは１００ｒｐｍ以下の低速で回転するがこれをダイレクトに減速体等を使用しないで駆動することは、インナーロータ型では回転子径が小さいため分解能が不足し、良好な回転ムラが得られない問題があった。分解能を大きくするには回転子極数を多くする必要があるがそのためには、回転子径を大きくする必要がある。
一方、ドラム駆動で回転電機をドラムの外部に設けると、小型化に問題が発生した。例えばＨＢ型のステッピングモータは回転子の極数が大きくできる構造であることが知られている。しかし更に極数を多くするために、そのままアウターロータ型にすると、大きな漏洩磁束が回転電機外周に出るため、特にドラム駆動や磁気デイスク駆動には問題があった。また永久磁石の回転軸と垂直な面方向の面積が小さく、十分な鎖交磁束が得られない問題もあった。
【０００３】
【発明が解決しようとする課題】
上記の従来技術での問題を解決することを課題とする。
【０００４】
【課題を解決するための手段】
【手段１】
略円環状部より外方向に放射状にＱ個設けられた固定子主極の各々の先端には複数Ｋ個の歯を有した、２個の該固定子で回転軸方向に磁化された永久磁石を挟持するか、または２個の該固定子の円環状磁性体の内周部に夫々円筒状永久磁石をその外周がお互いに異極となるように磁化して配し、２個の該固定子の主極部に渡ってコイルが巻かれ、エヤギャップを介してその内周に等ピッチでＲ個の歯を有し、回転軸方向厚さで、略（１／２）部で、Ｒ個の歯ピッチの（１／２）ずらせて構成された回転子と対向した外転型回転電機をドラムの内部に設け、該外転型回転電機の回転子外周部にドラム機能を有するかまたはドラムの内側で該回転子外周が連結され、該永久磁石の反回転子方向の漏洩磁束を回転軸心部に反発収束させ、ドラム外周部への漏洩磁束の影響を軽減させたことを、特徴とするドラム機能を有した、またはドラムに内臓された外転型回転電機。但し、Ｒ>ＫＱ。
【手段２】
手段１において、外転型回転電機は固定子の中央部に貫通中空穴を設け、その貫通穴を固定支持または該貫通穴に軸を通し、ドラムの回転支持軸としたことを特徴とするドラム機能を有した、またはドラムに内臓された外転型回転電機。
【手段３】
略円環状部より外方向に放射状に３ｍ個設けられた固定子主極の各々の先端には複数個の歯を有した、２個の該固定子で回転軸方向に磁化された永久磁石を挟持するか、または２個の該固定子の円環状磁性体の内周部に夫々円筒状永久磁石をその外周がお互いに異極となるように磁化して配し、２個の該固定子の主極部に渡ってコイルが巻かれ、１相分コイルがｍ個で構成した、３相巻線固定子を形成し、エヤギャップを介してその内周に等ピッチでＲ個の歯を有し、回転軸方向厚さで、略（１／２）部で、Ｒ個の歯ピッチの（１／２）ずらせて構成された回転子と対向した外転型回転電機において、Ｒ＝ｍ（３ｎ±１）であることを特徴とした外転型回転電機。但し、ｍ、ｎは1以上の整数。
【手段４】
手段３において、ｍ（３ｎ±１）>πＤであるであることを特徴とした外転型回転電機。但し、ｍ、ｎは1以上の整数。Ｄは回転子外径。
【手段５】
手段３において、各相の巻き終わりまたは一方同志を短絡し、巻き始めまたは他方側で３端子入力としたスター巻線、または１相の巻き終わりと次相の巻き始めを順次連結し、３個の該連結点にて３端子入力とした、３端子入力の３相巻線固定子を形成したことを特徴とした外転型回転電機。
【手段６】
手段３から５において、２相と３相を交互に励磁して駆動するか、各相の電流を極力正弦波に近似した階段状に増減した形のマイクロステップ駆動したことを特徴とした外転型回転電機の駆動法。
【手段７】
手段１〜５において、２個の固定子で挟持る永久磁石の回転軸方向から見た形状が該固定子と略同形状にして、ボンド磁石、または焼結磁石であることを特徴とした外転型回転電機。
【手段８】
手段１〜５において、永久磁石を挟持した２個の固定子を１固定子対とし、それらを軸方向にＰ対配置固定し、Ｐ対の固定子に渡り、同一位置の主極に同一のコイルを巻いた固定子と、それにエヤギャップを介して対向する回転子対を、回転軸方向にＰ個配置して設けたことを特徴とする外転型回転電機。
【０００５】
【実施例】
複写機の転写ドラム駆動の回転数は一般に４０〜１５０ｒｐｍ程度で回転電機から見ると低速回転の範囲と言える。このため、回転子極数が4〜８極程度の回転電機では減速体を使用して、回転子速度１５００〜７５０ｒｐｍから上記の回転数まで速度を落として使用していた。また２相ＨＢ型ステッピングモータはその極数は１００極程度に相当するが、そのため４０〜１５０ｒｐｍは容易でありトルクも十分出せるが、回転ムラが大きく、画像の精度、即ち、画質が悪いという問題があった。この回転ムラを改善するにはステッピングモータの分解能即ちステップ角を小さくすればよい。そのためには回転子の歯数を多くすればよい。しかし、インナーロータ型では回転子径が小さく、歯数を多くすることには限界があった。その解決策としてはＨＢ型ステッピングモータをアウターロータ（外転）型にすればよい。
図８は従来型のアウターロータ（外転）型回転電機であり、ＨＢ型ステッピングモータをアウターロータ化した縦断側面断面図である。図９はその横断正面断面図である。１１はコイルであり、固定子である円環状磁性体１２から放射状に設けられた複数の主極に巻かれている。各主極の先端には複数の歯（図９では歯は各３個）がエアギャップを介して、内周に均等に多数の歯を有する回転子１４と対向している。図８において、２個の回転子１４同志は回転軸方向に磁化された円筒またはデスク状永久磁石１５を挟持して、お互いに歯ピッチの１／２づらされて、回転子を構成している。固定子１２は該２個の回転子１４と対向して、珪素鋼板等を主極及び先端の歯を揃えて、積層されている。１３は固定子支持体であり、図示知てない軸受けと勘合し、前後のブラケットを支持して、回転電機を構成する。このような構造の外転型回転電機の問題点は１５の漏洩磁束が１４及び１５の外周方向にでることである。従って１４の外周に複写機のドラムを設けても、かなりの強さで磁界が存在し、トナーに磁性体粉が混じったりすると、画質を損ねたり、故障を引き起こすことになる。
【０００６】
図１は本発明を適応する外転型回転電機の縦断側面断面図である。図２はその横断正面断面図である。１はコイル、２は固定子鉄心であり、コイル１は、固定子である円環状磁性体２から放射状に設けられた複数の主極に巻かれている。各主極の先端には複数の歯（図２では歯は各3個）がエアギャップを介して、内周に均等に多数の歯を有する回転子８と対向している。図１において、８は８１と８２より成り、２個の回転子８１と８２同志は同じものであるが、互いに歯ピッチの１／２づらされて、回転子を構成している。固定子２は該２個の回転子８１及び８２と対向して、珪素鋼板等を主極及び先端の歯を揃えて、積層されたもので、それを２個で、同位置にて、軸方向に磁化した永久磁石３を挟持して構成され、各主極にはコイルが２個の２なる固定子主極に渡って巻かれている。
４は固定子支持体であり非磁性体であることが望ましく、軸受け５に勘合し６及び７なるブラケットで８なる回転子を回転自在に支持する。９はボルトであり、６、７、８を固定する役目をしている。１０はリード線であり、５なる軸受けの内輪の内径側から引き出すことで、回転子を両側より支持する所謂両持ち構造としている。このような構造を複写機ドラムの内部に設けると永久磁石が固定子側に設けてあるので、漏洩磁束は、ドラム外周部にはほとんど出なくなる。即ち、この外転型回転電機の回転子外周部にドラム機能を有するかまたはドラムの内側で該回転子外周が連結された場合、、永久磁石の漏洩磁束は永久磁石の反回転子方向に発生するので、図１で、永久磁石３のＮ極側から出た漏洩磁束は固定子支持体４の中空部に点線矢印で示した様に、固定子円環部４の内径の中心に反放射状に向い、その中心付近でＮ極の同極性磁束は反発しながら、軸方向に収束し、３のＳ極側付近に向い、放射状方向に３のＳ極に向かうので、漏洩磁束を回転軸心部に反発収束させ、ドラム外周部への漏洩磁束の影響を軽減させろことが出来る。
図１には永久磁石３は２個の固定子で挟持された構造で示したが、図示は省略するが、図１で３を単なる非磁性スペーサとし、２個の２の夫々の内周部と４との間に円筒状永久磁石を設け、２個の２と接する磁石の外周がお互いに異極性となるように磁化配置した構造のものでも前述した図１の構造と同様な外転型回転電機としても、また漏洩磁束に関しても、同様の効果が得られる。この場合は４は磁性体であることが望ましい。
またこの外転型回転電機において、回転子の歯数をＲ個とし、各主極の先端の小歯数をＫ個とし、主極の総数をＱ個とすれば、Ｋ個の歯ピッチとＲ個の歯ピッチはほぼ等しくするため、固定子スロット部を考慮すると、Ｒ>ＫＱの関係が成り立つ。
【０００７】
また図１で、４は中心部が空洞になっているので、この空洞部に通し棒を貫通させるとドラム駆動機構が簡素化出来る。これを説明したのが図７である。２０が該外転型回転電機であり、２１がその中空穴に貫通した通し棒、即ちドラムの軸２１である。２２はドラムであり、２０の回転子外周に連結されている。２３はドラムカバー、２４は軸受けである。尚、この軸受け２４は全く使用しないで、モータ２０に使用されている軸受けで併用、代用してもよく、軸受け２４を１個のみの使用でも良い。
【０００８】
この外転型回転電機は特に３相固定子にすると、振動が少なく、ドラク駆動として、適したものとなる。固定子主極数を３ｍ個とすると、３相の場合はｉ相分主極数はｍ個となる。そして回転子歯数をＲ個とすると、次の（１）式が成立する。

上式の左辺も右辺もこの外転型３相機を３相のステッピングモータとして駆動したときの、ステップ角度を表している。これを整理すると、（２）式となる。

この関係式を有した３相機であることが、望ましい。
（２）式で、ｍ＝２の６主極で、ｎ＝１７とすると、Ｒ＝１００でステップ角が０．６°、また、ｍ＝４の１２主極で、ｎ＝１１とすると、Ｒ＝１２８で、ステップ角が０．４６８７５°となる。
【０００９】
回転子は珪素鋼板よりプレスで打ち抜き積層形成する。この場合、ドラムに応用する場合、回転ムラを良くするには、歯数Ｒを極力多くする必要がある。Ｒを多くすると歯幅は細くなり、細すぎると、プレス打ち抜きができなくなる。その限界は概略、歯幅が珪素鋼板の板厚ｔまでと言われている。回転子の外径をＤとし、歯幅と谷（溝）幅を同じとすれば歯ピッチは２ｔとなるので、次式が概略成立する。

一般に小型回転機に使用される珪素鋼板の板厚ｔは０．５ｍｍである。ｔ＝０．５を（３）式に代入してＲ＝πＤとなるが、転写ドラムに使用する場合は分解能が高いことが必要であり、
Ｒ＝πＤなるＲの値以上ないと、実用的には画質が悪く使用できない。（３）式に（２）式とＲ＝πＤを代入して、（４）式を得る。

【００１０】
本発明の外転型回転電機を３相機にすると、スター、またはデルタ結線が可能で、３端子入力で駆動出来る。固定子主極数３ｍ個で、ｍ＝２として、６主極の場合で、スター結線の場合を図３に、デルタ結線の場合を図４に示す。これらの結線の３端子モータ入力には図５にスター結線で示すが、電流方向が反転するバイポーラ駆動で、トランジスターが６個のブリッジで駆動できる。２相機では８個のトランジスタが必要なので、３相の方が、性能が良く、且、駆動回路も安価になる。
【００１１】
３相機にすると、永久磁石によるエヤギャップの磁束密度である界磁に含まれる第３高調波がその構造からキャンセルされる。また、電流に含まれる高調波も２相励磁であるフルステップより、２相と３相を交互に励磁する２―３相励磁駆動とすることで、電流波形がより、正弦波に近くなるため、少なく出来る。３相で２―３相の励磁シーケンス、及びモータ電流波形を図６に示す。更には、各相の電流を極力正弦波に近似した階段状に増減した形のマイクロステップ駆動により、界磁と電流の積であるトルクの中に、振動トルクが減少し、低速のドラム駆動には適した駆動法となる。
【００１２】
本方式の外転型回転電機には永久磁石を２個の固定子でサンドイッチ状に挟んで固定子を構成するが、２個の固定子で挟持る永久磁石の回転軸方向から見た形状が該固定子と略同形状であれば、磁石の固定子との接触面積も最大になり、鎖交磁束を大きく出来る。しかし、その場合、永久磁石の形状が複雑になる。また回転軸方向の永久磁石の厚みは極力薄いものが望ましい。何故なら、その磁石厚みの部分は固定子に歯がなく、回転子との間でトルク発生に貢献しないからである。それらを考慮すると、複雑な形状の永久磁石に適するボンド磁石、または薄厚でもパーミアンス係数の高く磁束の大きい焼結磁石が最適である。
【００１３】
高いトルクをモータの外径を変えずに得るには、軸方向に珪素鋼板積み厚を増せばよいが、この時、永久磁石からの磁束補給量はほぼ同じなので、結果として磁束密度が減少して、トルクが軸方向にモータを鉄心部のみ伸びても増えない。この場合は、永久磁石を挟持した２個の固定子を１固定子対とし、それらを軸方向にＰ対配置固定し、Ｐ対の固定子に渡り、同一位置の主極に同一のコイルを巻いた固定子と、それにエヤギャップを介して対向する回転子対を、回転軸方向にＰ個配置して設ける様にすればよい。
但し、Ｐは整数。
【００１４】
【発明の効果】
１）複写機やプリンター等のドラム駆動において、従来の方式はドラム外に回転電機があり、減速体やタイミングベルト等でドラム外部からドラムを駆動していた。これに対し、本発明を適応すると、小型コンパクトとなり、ドラムそのものが、回転しながら、分解能も高いため、転写ドラムとしてのその機能を発揮できる。
また回転電機の漏洩磁束が回転電機内部に封じ込まれ、ドラム外部にはほとんど出なくなる。
２）外転型回転電機の外周部にドラムを設け、外転型回転電機の中空部に貫通してその内径に勘合する軸を通し、固定軸として、ドラムの回転軸心を兼務させることで、小型コンパクトなドラムアクチュエータとなる。
３）Ｒ＝ｍ（３ｎ±１）やｍ（３ｎ±１）>πＤを満たす、回転子の歯数を選べば、高精度で高分解能な回転電機が実現する。
３相巻線でスターまたはデルタ結線として、３端子で駆動回路をシンプルにできる。
駆動を２―３相やマイクロステツプとすることで、オープンループ等でも低回転ムラとなり、ドラム駆動に適したものとなる。
固定子に有する永久磁石を、固定子鉄心と同形状にし、ボンド磁石や焼結磁石とすることで、永久磁石の磁束を大きくでき、且磁石を薄くできる。
本発明の回転電機の固定子対を２段等に重ねることで、高トルクが容易に得られる回転電機となる。
【図面の簡単な説明】
【図１】本発明に用いる外転型回転電機の側面構造図
【図２】本発明に用いる外転型回転電機の正面構造図
【図３】本発明のモータに適用する結線図
【図４】本発明のモータに適用する別の結線図
【図５】本発明に適用する駆動回路とモータの結線図
【図６】本発明に適用する２―３相駆動の励磁と電流
【図７】本発明のドラム回転構造図
【図８】従来の外転型回転電機の側面断面図
【図９】従来の外転型回転電機の正面断面図
【符号の説明】
１、１１コイル
２、１２固定子鉄心
３、１５永久磁石
４、１３固定子支持体、
５、２４軸受け
６、７ブラケット
２３ブラケット
８回転子
９固定ボルト
１０リード線
１４回転子
２０外転型回転電機
２１固定軸
２２ドラム[0001]
[Industrial application fields]
The present invention relates to an abduction type rotating electrical machine suitable for driving a transfer drum or the like of a copying machine.
[0002]
[Prior art]
The transfer drum of a copying machine rotates at a low speed of 100 rpm or less, but driving it directly without using a speed reducer, etc., the inner rotor type has a small rotor diameter, resulting in insufficient resolution and good rotation unevenness. There was a problem that could not be obtained. In order to increase the resolution, it is necessary to increase the number of rotor poles. For this purpose, it is necessary to increase the rotor diameter.
On the other hand, when the rotating electric machine is provided outside the drum by driving the drum, there is a problem in miniaturization. For example, it is known that an HB type stepping motor has a structure that can increase the number of poles of a rotor. However, if the outer rotor type is used as it is in order to further increase the number of poles, a large leakage magnetic flux appears on the outer periphery of the rotating electric machine, which has a problem particularly in drum driving and magnetic disk driving. There is also a problem that the area in the plane direction perpendicular to the rotation axis of the permanent magnet is small, and a sufficient interlinkage magnetic flux cannot be obtained.
[0003]
[Problems to be solved by the invention]
It is an object of the present invention to solve the above-described problems in the prior art.
[0004]
[Means for Solving the Problems]
[Means 1]
Permanent magnets magnetized in the direction of the rotation axis by two stators having a plurality of K teeth at the tip of each of the Q main stator poles provided radially outward from the substantially annular portion. Or two permanent magnets are magnetized on the inner circumference of the annular magnetic body of the two stators so that their outer circumferences have different polarities. A coil is wound over the main pole part of the child, and has R teeth at an equal pitch on the inner periphery via an air gap, and R pieces are approximately (1/2) in thickness in the rotation axis direction. An abduction type rotating electrical machine facing a rotor that is shifted by (1/2) of the tooth pitch is provided inside the drum, and the outer peripheral part of the rotor of the abduction type rotating electrical machine has a drum function or a drum. The outer periphery of the rotor is connected to the inner side of the drum, and the leakage magnetic flux in the counter-rotor direction of the permanent magnet is rebounded and converged on the rotation shaft center portion, Epicycloidal rotary electric machine that reduce the effect of the leakage magnetic flux, having a drum that features, or have been built on the drum to. However, R> KQ.
[Means 2]
In the first aspect, the outer rotation type rotating electrical machine has a through-hole formed in the center of the stator, and the through-hole is fixedly supported or a shaft is passed through the through-hole to serve as a rotation support shaft of the drum. An abduction type rotating electrical machine having a function or built in a drum.
[Means 3]
A permanent magnet magnetized in the direction of the rotation axis by two stators having a plurality of teeth at the tip of each of the stator main poles provided 3 m radially outward from the substantially annular portion. The two stators are formed by sandwiching or magnetizing cylindrical permanent magnets so that their outer circumferences have different polarities from each other on the inner circumference of the annular magnetic body of the two stators. A coil is wound over the main pole portion of the wire, forming a three-phase winding stator consisting of m coils for one phase, and having R teeth at an equal pitch through the air gap on the inner circumference. In an external rotation type rotating electrical machine opposed to a rotor having a thickness in the rotational axis direction, which is substantially (1/2) part and is configured to be shifted by (1/2) of R tooth pitches, R = m ( An abduction type rotating electrical machine characterized by 3n ± 1). However, m and n are integers of 1 or more.
[Means 4]
An abduction type rotating electrical machine according to means 3, wherein m (3n ± 1)> πD. However, m and n are integers of 1 or more. D is the outer diameter of the rotor.
[Means 5]
In the means 3, the winding end of each phase or one side of each phase is short-circuited, and the star winding having three terminals input on the winding start or the other side, or the winding end of one phase and the winding start of the next phase are sequentially connected, An abduction type rotary electric machine characterized by forming a three-terminal input three-phase winding stator having a three-terminal input at the connection point.
[Means 6]
In the means 3 to 5, the abduction is characterized in that the two-phase and three-phase are driven by being alternately excited or the current of each phase is increased or decreased in a step-like manner approximating a sine wave as much as possible. Driving method of type rotating electric machine.
[Means 7]
In the means 1 to 5, the shape of the permanent magnet sandwiched between the two stators as viewed from the rotational axis direction is substantially the same as that of the stator, and is a bonded magnet or a sintered magnet. Rotating rotary electric machine.
[Means 8]
In means 1 to 5, two stators sandwiching a permanent magnet are used as one stator pair, and they are arranged and fixed in P pairs in the axial direction, over the P pairs of stators, and the same main pole at the same position. An abduction type rotating electrical machine characterized in that a stator around which a coil is wound and P rotor pairs facing each other via an air gap are arranged in the direction of the rotation axis.
[0005]
【Example】
The rotation speed of the copying machine driven by the copying machine is generally about 40 to 150 rpm, which can be said to be a range of low-speed rotation when viewed from the rotating electric machine. For this reason, in a rotating electrical machine having the number of rotor poles of about 4 to 8 poles, a speed reducer is used, and the speed is reduced from the rotor speed of 1500 to 750 rpm to the above speed. The two-phase HB type stepping motor corresponds to about 100 poles. Therefore, 40 to 150 rpm is easy and sufficient torque can be produced, but the rotation unevenness is large, and the accuracy of the image, that is, the image quality is poor. was there. In order to improve the rotation unevenness, the resolution of the stepping motor, that is, the step angle may be reduced. For this purpose, the number of teeth of the rotor may be increased. However, the inner rotor type has a small rotor diameter, and there is a limit to increasing the number of teeth. As a solution, the HB type stepping motor may be an outer rotor (external rotation) type.
FIG. 8 shows a conventional outer rotor (external rotation) type rotating electrical machine, which is a longitudinal sectional side view of an HB type stepping motor formed as an outer rotor. FIG. 9 is a cross-sectional front sectional view thereof. A coil 11 is wound around a plurality of main poles provided radially from an annular magnetic body 12 that is a stator. At the tip of each main pole, a plurality of teeth (three teeth in FIG. 9) are opposed to the rotor 14 having an even number of teeth on the inner periphery through an air gap. In FIG. 8, two rotors 14 sandwich a cylindrical or desk-like permanent magnet 15 magnetized in the direction of the rotation axis and are halved from each other to form a rotor. . The stator 12 faces the two rotors 14 and is laminated with a silicon steel plate or the like with the main pole and tip teeth aligned. Reference numeral 13 denotes a stator support, which is engaged with a bearing (not shown) and supports the front and rear brackets to constitute a rotating electrical machine. The problem with the outer rotation type rotating electrical machine having such a structure is that 15 leakage magnetic fluxes appear in the outer circumferential direction of 14 and 15. Therefore, even if the drum of the copying machine is provided on the outer periphery of 14, if a magnetic field exists with a considerable strength and the magnetic powder is mixed in the toner, the image quality is deteriorated or a failure is caused.
[0006]
FIG. 1 is a longitudinal sectional side view of an abduction type rotating electrical machine to which the present invention is applied. FIG. 2 is a cross-sectional front sectional view thereof. Reference numeral 1 denotes a coil, 2 denotes a stator core, and the coil 1 is wound around a plurality of main poles provided radially from an annular magnetic body 2 as a stator. At the tip of each main pole, a plurality of teeth (three teeth in FIG. 2) are opposed to the rotor 8 having an even number of teeth on the inner periphery through an air gap. In FIG. 1, 8 is composed of 81 and 82, and the two rotors 81 and 82 are the same, but are divided by half of the tooth pitch to constitute a rotor. The stator 2 is a laminate of silicon steel plates and the like facing the two rotors 81 and 82, with the main pole and tip teeth aligned, and two of them are placed at the same position at the shaft. A permanent magnet 3 magnetized in the direction is sandwiched, and a coil is wound around two main stator poles on each main pole.
Reference numeral 4 denotes a stator support, which is preferably a non-magnetic material, and is fitted to the bearing 5 to rotatably support the rotor 8 with

brackets

6 and 7. Reference numeral 9 denotes a bolt which serves to fix 6, 7, and 8. A lead wire 10 has a so-called doubly-supported structure in which the rotor is supported from both sides by being pulled out from the inner diameter side of the inner ring of the bearing 5. When such a structure is provided inside the copying machine drum, the permanent magnet is provided on the stator side, so that almost no leakage magnetic flux appears on the outer periphery of the drum. That is, if the outer periphery of the rotor of this abduction-type rotating electrical machine has a drum function or the outer periphery of the rotor is connected inside the drum, the leakage flux of the permanent magnet is generated in the direction opposite to the rotor of the permanent magnet. Therefore, in FIG. 1, the leakage magnetic flux emitted from the N pole side of the permanent magnet 3 is anti-radial at the center of the inner diameter of the stator ring portion 4 as indicated by the dotted arrow in the hollow portion of the stator support 4. Near the center, the same polarity magnetic flux of N pole is repelled and converges in the axial direction, toward the S pole side of 3 and toward the S pole of 3 in the radial direction. It is possible to reduce the influence of the leakage magnetic flux on the outer periphery of the drum by rebounding and converging on the part.
FIG. 1 shows a structure in which the permanent magnet 3 is sandwiched between two stators, but although not shown, in FIG. 1, 3 is a simple nonmagnetic spacer, and each of the two inner peripheral portions of two 1 and 4 have a structure in which a cylindrical permanent magnet is provided so that the outer circumferences of the two magnets in contact with 2 have different polarities from each other. The same effect can be obtained for the rotating electrical machine and for the leakage magnetic flux. In this case, 4 is preferably a magnetic material.
In this abduction type rotating electrical machine, if the number of teeth of the rotor is R, the number of small teeth at the tip of each main pole is K, and the total number of main poles is Q, K tooth pitches and Since the R tooth pitches are substantially equal, the relationship of R> KQ is established when the stator slot portion is considered.
[0007]
Further, in FIG. 1, since the central portion of 4 is hollow, the drum driving mechanism can be simplified by passing a through-rod through the hollow portion. This is illustrated in FIG. Reference numeral 20 denotes the abduction-type rotating electrical machine, and reference numeral 21 denotes a through-rod penetrating through the hollow hole, that is, a drum shaft 21. A drum 22 is connected to the outer periphery of the 20 rotors. Reference numeral 23 is a drum cover, and 24 is a bearing. Note that this bearing 24 is not used at all, and a bearing used in the motor 20 may be used together or substituted, or only one bearing 24 may be used.
[0008]
When this abduction type rotating electrical machine is a three-phase stator in particular, there is little vibration and it is suitable as a drag drive. If the number of stator main poles is 3 m, the number of i-phase main poles is m in the case of three phases. When the number of rotor teeth is R, the following equation (1) is established.

Both the left side and the right side of the above equation represent the step angle when this abduction type three-phase machine is driven as a three-phase stepping motor. If this is rearranged, it will become (2) Formula.

A three-phase machine having this relational expression is desirable.
In equation (2), if m = 6 main poles and n = 17, then R = 100 and the step angle is 0.6 °, and m = 4 12 main poles and n = 11. At R = 128, the step angle is 0.46875 °.
[0009]
The rotor is punched out of a silicon steel plate and formed by pressing. In this case, when applied to a drum, it is necessary to increase the number of teeth R as much as possible in order to improve rotation unevenness. If R is increased, the tooth width becomes narrow, and if it is too thin, press punching cannot be performed. The limit is generally said that the tooth width is up to the thickness t of the silicon steel sheet. If the outer diameter of the rotor is D, and the tooth width and the trough (groove) width are the same, the tooth pitch is 2t.

In general, the thickness t of a silicon steel plate used for a small rotating machine is 0.5 mm. By substituting t = 0.5 into the equation (3), R = πD, but when used for a transfer drum, the resolution needs to be high.
If it is not more than the value of R such that R = πD, the image quality is practically poor and cannot be used. Substituting equation (2) and R = πD into equation (3), equation (4) is obtained.

[0010]
If the external rotating electric machine of the present invention is a three-phase machine, star or delta connection is possible and it can be driven with a three-terminal input. FIG. 3 shows a case of star connection and FIG. 4 shows a case of delta connection in the case of 6 main poles with 3 m stator main poles and m = 2. The three-terminal motor input of these connections is shown by a star connection in FIG. 5, and the transistor can be driven by six bridges by bipolar drive in which the current direction is reversed. Since the two-phase machine requires eight transistors, the three-phase machine has better performance and the drive circuit is cheaper.
[0011]
When the three-phase machine is used, the third harmonic contained in the field, which is the magnetic flux density of the air gap by the permanent magnet, is canceled from the structure. In addition, since the harmonics included in the current are driven by 2-3 phase excitation, which excites the 2 phase and 3 phase alternately from the full step which is 2 phase excitation, the current waveform becomes closer to a sine wave. I can do less. Fig. 6 shows the 3-phase excitation sequence of 2-3 phases and the motor current waveform. In addition, the micro step drive in which the current of each phase is increased or decreased in a step-like manner that approximates a sine wave as much as possible reduces the vibration torque in the torque that is the product of the field and current, thereby enabling low-speed drum drive. Is a suitable driving method.
[0012]
In this type of external rotating electric machine, a permanent magnet is sandwiched between two stators to form a stator, but the shape of the permanent magnet sandwiched between the two stators is viewed from the rotational axis direction. If the shape is substantially the same as that of the stator, the contact area between the magnet and the stator is maximized, and the flux linkage can be increased. However, in that case, the shape of the permanent magnet becomes complicated. The thickness of the permanent magnet in the direction of the rotation axis is preferably as thin as possible. This is because the magnet thickness portion has no teeth on the stator and does not contribute to torque generation with the rotor. Considering them, a bonded magnet suitable for a permanent magnet having a complicated shape, or a sintered magnet having a small permeance coefficient and a high magnetic flux is optimal.
[0013]
In order to obtain high torque without changing the outer diameter of the motor, it is only necessary to increase the thickness of the silicon steel plate in the axial direction. At this time, the amount of magnetic flux supplied from the permanent magnet is almost the same, and as a result, the magnetic flux density decreases. Thus, the torque does not increase even if the motor extends only in the iron core in the axial direction. In this case, two stators sandwiching a permanent magnet are used as one stator pair, and they are arranged and fixed in P pairs in the axial direction. The same coil is placed on the main pole at the same position across the P pair of stators. A wound stator and P rotor pairs opposed to each other via an air gap may be arranged in the rotational axis direction.
However, P is an integer.
[0014]
【The invention's effect】
1) In the drum driving of a copying machine, a printer, etc., the conventional method has a rotating electric machine outside the drum, and the drum is driven from the outside of the drum by a speed reducer, a timing belt, or the like. On the other hand, when the present invention is applied, it becomes small and compact, and since the drum itself rotates and has high resolution, its function as a transfer drum can be exhibited.
Moreover, the leakage magnetic flux of the rotating electrical machine is sealed inside the rotating electrical machine and hardly comes out of the drum.
2) By providing a drum on the outer periphery of the outer rotation type rotating electrical machine, passing a shaft that passes through the hollow portion of the outer rotation type rotating electrical machine and fits into the inner diameter thereof, and also serves as a rotating shaft center of the drum as a fixed shaft It becomes a small and compact drum actuator.
3) If the number of teeth of the rotor satisfying R = m (3n ± 1) or m (3n ± 1)> πD is selected, a highly accurate and high resolution rotating electrical machine can be realized.
Three-phase winding can be used for star or delta connection, and the drive circuit can be simplified with three terminals.
By setting the driving to 2-3 phases or microsteps, even in an open loop or the like, low rotation unevenness is achieved, which is suitable for drum driving.
By making the permanent magnet in the stator the same shape as the stator core and making it a bonded magnet or a sintered magnet, the magnetic flux of the permanent magnet can be increased and the magnet can be made thinner.
By rotating the stator pairs of the rotating electrical machine of the present invention in two stages or the like, the rotating electrical machine can easily obtain high torque.
[Brief description of the drawings]
FIG. 1 is a side structural view of an abduction type rotating electrical machine used in the present invention. FIG. 2 is a front structural view of an abduction type rotating electrical machine used in the present invention. FIG. 3 is a connection diagram applied to a motor of the present invention. ] Another connection diagram applied to the motor of the present invention [FIG. 5] Connection diagram of drive circuit and motor applied to the present invention [FIG. 6] Excitation and current of 2-3 phase drive applied to the present invention [FIG. 7] FIG. 8 is a side sectional view of a conventional abduction type rotating electrical machine. FIG. 9 is a front sectional view of a conventional abduction type rotating electrical machine.
1, 11

Coil

2, 12

Stator core

3, 15

Permanent magnet

4, 13 Stator support,
5, 24

Bearing

6, 7 Bracket 23 Bracket 8 Rotor 9 Fixing bolt 10 Lead wire 14 Rotor 20 Abduction type rotating electrical machine 21 Fixed shaft 22 Drum

Claims

A stator core is formed by providing a plurality (Q) of stator main poles having a plurality of (K) teeth at each tip radially outward from the substantially annular magnetic body portion. A cylinder in which two stator cores are arranged at the same position and magnetized so that the outer circumferences of the two stator cores have different polarities from each other on the inner circumferences of the magnetic parts of the two stator cores A permanent magnet is arranged, coils are wound around the main poles of the two stator cores to form a stator, and the stator cores are rotated so as to face the tips of the main poles via an air gap. The rotor is rotatably arranged, and the rotor has a plurality of (R) teeth at an equal pitch on the inner periphery thereof, and the R tooth pitch is 1 at a position approximately half the thickness in the rotation axis direction. / 2 is configured to be shifted, and has a R> KQ the relationship, or the outer peripheral portion of the rotor has a drum feature Other outer periphery of the rotor is connected to the inside of the drum to the leakage magnetic flux of the anti-rotor direction of the permanent magnet is repelled converge to the rotation axis part, and reduce the effects of leakage flux to the drum outer peripheral portion An abduction type rotating electrical machine characterized by

In claim 1, the solid is in the center of the stator is provided with a through hollow space, through the shaft into the through hole, epicycloidal rotary electric machine has a rotation shaft of the drum.

A stator core is formed by providing 3 m stator main poles having a plurality of teeth at each tip radially outward from the substantially annular magnetic body, and two stator cores are located at the same position. And two cylindrical stator magnets magnetized so that the outer circumferences of the two stator cores have different polarities from each other, are arranged on the inner circumference of each of the magnetic parts of the two stator cores. A three-phase winding stator is formed by winding a coil so that one phase is composed of m pieces over each main pole of the stator core, and at the tip of each main pole of the stator core A rotor is rotatably arranged so as to face each other via an air gap, and the rotor has a plurality of (R) teeth at an equal pitch on the inner periphery thereof, and at a position approximately half the thickness in the rotation axis direction. , R tooth pitch is shifted by 1/2, and R = m (3n ± 1) (where m and n are integers of 1 or more) Epicycloidal rotary electric machine, characterized in that had that relationship.

4. An external rotation type rotating electrical machine according to claim 3, wherein when the outer diameter of the rotor is D, m (3n ± 1)> πD.

In claim 3, the winding end of each phase or one side of each phase is short-circuited, and the star winding having three terminals input on the winding start or the other side, or the winding end of one phase and the winding start of the next phase are sequentially connected. An abduction type rotating electrical machine characterized by forming a three-terminal input three-phase winding stator having three terminal inputs at the connection points.

6. An external rotation type rotating electrical machine according to claim 3, wherein the two-phase and three-phase electric motors are driven by exciting them alternately, or the current of each phase is increased or decreased in a staircase pattern that approximates a sine wave as much as possible. A driving method for an abduction type rotating electrical machine, characterized in that the microstep driving is performed.