JPS62152362A - Brushless motor - Google Patents

Abstract

PURPOSE:To facilitate the magnetization of the permanent magnet of a rotor and reduce the unevenness of the characteristic, by magnetizing the permanent magnet with skew at a specified angle, and by setting a magnetism-sensitive element so that the polarity of a central section in the axial direction of the permanent magnet may be detected. CONSTITUTION:A rotor 1 having a permanent magnet 2 is organized by fixing the permanent magnet 2 on the internal peripheral wall of a cup-formed yoke 3, and a rotary shaft 4 on the center of a bottom section. The permanent magnet 2 is alternately magnetized in the circumferential direction. So far as the state of this magnetization is concerned, one side of two different pole boundaries formed in the range of the electrical angle of 360 degrees is skewed at the electrical angle of 120 degrees. Besides, a magnetism-sensitive element 12 is set so that the polarity of a central section in the axial direction of the permanent magnet 2 may be detected.

Description

【発明の詳細な説明】 ［技術分野］ 本発明は、ホール素子のような磁気感応素子により永久
磁石回転子の極性を検出し、その検出状況に応じ固定子
磁極に所要極性を付与して回転子を自起動回転させる無
刷子電動機に関する。[Detailed Description of the Invention] [Technical Field] The present invention detects the polarity of a permanent magnet rotor using a magnetic sensing element such as a Hall element, and rotates the stator by imparting a required polarity to the stator magnetic poles according to the detection situation. This invention relates to a brushless electric motor that automatically rotates a motor.

［背景技術］ この種の無刷子電動機は、２極あるいは４極の固定子と
着磁状態を軸方向に２段とした２極４極あるいは４極８
極の永久磁石回転子を組合せて、レラクタンストルクと
これの２倍の周期を持つ電流トルクを生ぜしめ、かつ電
流トルクのピーク値とレラクタンストルクの零点が一致
するよう合成して常に一方向の回転トルクを得るものが
一般的である。また永久磁石回転子の変形例として、第
６図の如く、着磁状態を軸方向に２段とし固定子磁極と
ともに回転トルクを発生する側に無着磁部分が存在する
ようにしたものもある。[Background Art] This type of brushless motor has a 2-pole or 4-pole stator and a 2-pole 4-pole or 4-pole 8-pole stator with two stages of magnetization in the axial direction.
By combining the permanent magnet rotors of the poles, a reluctance torque and a current torque with twice the period of this are generated, and the peak value of the current torque and the zero point of the reluctance torque are combined so that they are always unidirectional. It is common to obtain a rotational torque of . In addition, as a modification of the permanent magnet rotor, as shown in Fig. 6, there is also one in which the magnetization state is set in two stages in the axial direction so that a non-magnetized portion exists on the side that generates rotational torque together with the stator magnetic poles. .

これらはいずれも永久磁石回転子の着磁状態を軸方向に
２段にして異ならせであるため、着磁工程が複雑になっ
たり、着磁の細分化によって電動機特性のばらつき原因
になる等の問題を含んでいる。In both of these cases, the magnetization state of the permanent magnet rotor is made different in two stages in the axial direction, which may complicate the magnetization process or cause variations in motor characteristics due to subdivision of magnetization. contains problems.

［発明の目的］ 本発明は、上記事由に鑑みてなしたもので、その目的と
するところは、回転子に用いる永久磁石の着磁を簡易な
ものとし、しかも電動機特性のばらつきが軽減できる無
刷子電動機の提供にある。[Object of the Invention] The present invention was made in view of the above reasons, and its purpose is to simplify the magnetization of permanent magnets used in the rotor and to reduce variations in motor characteristics. Offering brush motors.

［発明の開示］ 本発明の無刷子電動機は、周方向に異極が交互に着磁さ
れた円筒状の永久磁石を有する回転子と、主磁極と補助
磁極を交互に等間隔に有した固定子と、固定子の主磁極
に巻装された巻線と、回転子の極性を検出して巻線の電
流を切り換える磁気感応素子とよりなる無刷子電動機に
おいて、永久磁石を、電気角３６０度の範囲で形成され
る２１面の異極境界の一方が電気角１２０度にわたって
スキューした着磁とし、磁気感応素子を、永久磁石の軸
方向中央部の極性を検出するよう配設したことを特徴と
し、これにより上記目的を達成したものである。[Disclosure of the Invention] The brushless electric motor of the present invention includes a rotor having a cylindrical permanent magnet in which different poles are alternately magnetized in the circumferential direction, and a fixed rotor having main magnetic poles and auxiliary magnetic poles alternately spaced at equal intervals. In a brushless motor, which consists of a winding wound around the main magnetic pole of the stator, and a magnetic sensing element that detects the polarity of the rotor and switches the current in the winding, the permanent magnet is One of the 21 different-polar boundaries formed in the range of 21 is magnetized with a skew of 120 electrical degrees, and a magnetic sensing element is arranged to detect the polarity of the axial center of the permanent magnet. With this, the above objective has been achieved.

（実施例） 以下本発明の一実施例を第１図乃至第５図に基づいて説
明する。(Example) An example of the present invention will be described below based on FIGS. 1 to 5.

１は円筒状の永久磁石２を有する回転子で、カップ状ヨ
ーク３の内周壁に永久磁石２を固定し、底部中央に回転
軸４を固着して構成される。永久磁石２は周方向に異極
（Ｎ極、Ｓ極）が交互に着磁されている。この着磁状態
は永久磁石２の周方向を展開した場合、第３図の如く、
電気角３６０度の範囲で形成される２個の異極境界の一
方が電気角１２０度にわたってスキューした着磁としで
ある。この実施例の極数は２であるが、これを４あるい
はそれ以上にすることも可能である。Reference numeral 1 denotes a rotor having a cylindrical permanent magnet 2, which is constructed by fixing the permanent magnet 2 to the inner peripheral wall of a cup-shaped yoke 3 and fixing a rotating shaft 4 to the center of the bottom. The permanent magnet 2 is magnetized with different poles (N pole, S pole) alternately in the circumferential direction. When the permanent magnet 2 is expanded in the circumferential direction, this magnetized state is as shown in Fig. 3.
The magnetization is such that one of two different polar boundaries formed in a range of 360 electrical degrees is skewed over 120 electrical degrees. Although the number of poles in this embodiment is two, it is also possible to increase the number to four or more.

５は積層鉄心よりなる固定子で、回転子１　（永久磁石
２）の極数に等しい主磁極６（本実施例では第１主磁極
５ａ、第２主磁極６ｂの計２４ｖＡ）と補助磁極７（本
実施例では第１補助磁極７ａ、第２補助磁極７ｂの計２
個）を交互に等間隔に有して各磁極面６ｃ、６ｄ、７ｃ
、７ｄが永久磁石２に対し径方向に対面°している。ま
た本実施例では第１．第２主磁掻の磁極面６ｃ、６ｄ巾
を中心角約１４０度、第１．第２補助磁極の磁極面７ｃ
。Reference numeral 5 denotes a stator made of a laminated iron core, which has a main magnetic pole 6 (total 24 vA of the first main magnetic pole 5a and second main magnetic pole 6b in this embodiment) equal to the number of poles of the rotor 1 (permanent magnet 2) and an auxiliary magnetic pole 7. (In this embodiment, there are a total of two auxiliary magnetic poles, the first auxiliary magnetic pole 7a and the second auxiliary magnetic pole 7b.
) are alternately spaced at equal intervals on each magnetic pole surface 6c, 6d, 7c.
, 7d face the permanent magnet 2 in the radial direction. In addition, in this embodiment, the first. The width of the magnetic pole faces 6c and 6d of the second main magnetic scraper is set at a central angle of about 140 degrees, and the width of the magnetic pole faces 6c and 6d of the second main magnetic scraper is set at a central angle of about 140 degrees. Magnetic pole surface 7c of second auxiliary magnetic pole
.

７ｄ巾を中心角約２０度としである。The width is 7d and the center angle is approximately 20 degrees.

この固定子５は、本体ケーシング８に固定された円筒状
支持体９の外周に固設される。また円筒状支持体９の内
周にはベアリング１０が装着され、これに回転軸４が回
動可能に支持される。This stator 5 is fixed to the outer periphery of a cylindrical support 9 fixed to the main casing 8 . Further, a bearing 10 is mounted on the inner periphery of the cylindrical support body 9, and the rotating shaft 4 is rotatably supported by the bearing 10.

１）は固定子５の各主磁極６ａ、６ｂにバイファイラ巻
で巻装された２相の巻線で、電流が流されることにより
各主磁極６ａ、６ｂにＮ、Ｓ極性又はＳ、Ｎ極性を付与
する。1) is a two-phase winding wound with bifilar winding around each main magnetic pole 6a, 6b of the stator 5, and when a current is passed through each main magnetic pole 6a, 6b, each main magnetic pole 6a, 6b has N, S polarity or S, N polarity. Grant.

１２は固定子５に装着されるホール素子からなる磁気感
応素子で、回転子１の永久磁石２の極性の一方（本実施
例ではＮ極）を検出し、その出力が一般的な電流切換回
路に入力されて巻線１）の電流を切り換える。この磁気
感応素子１２は、第３図の如く、永久磁石２の軸方向中
央部に対面するよう配設されてその部分の極性を検出す
る。Reference numeral 12 denotes a magnetic sensing element consisting of a Hall element attached to the stator 5, which detects one of the polarities (in this example, the N pole) of the permanent magnet 2 of the rotor 1, and its output is used in a general current switching circuit. is input to switch the current in winding 1). As shown in FIG. 3, this magnetic sensing element 12 is arranged so as to face the axially central portion of the permanent magnet 2, and detects the polarity of that portion.

電流切換回路は、例えば第５図の如きもので、磁気感応
素子１２はＮ極を検出するとトランジスタＱ３をオンし
てトランジスタＱｌをオン、トランジスタＱ２をオフし
、第１巻線１）ａに電流を流して第１主磁極６ａにＮ極
を付与する。またＳ極を検出するとトランジスタＱ３を
オフしてトランジスタＱ１をオフ、トランジスタＱ２を
オンし・第２巻線１）ｂに電流を流して第２主磁極６ｂ
にＮ極を付与する。この場合、例えば前者において第１
主磁極６ａにＮ極が付与されると、第２主磁極６ｂと各
補助磁極？ａ、７ｂのそれぞれは磁気回路上、第１主磁
極６ａよりも弱いＳ極を示す。The current switching circuit is, for example, as shown in FIG. 5, and when the magnetic sensing element 12 detects the N pole, it turns on the transistor Q3, turns on the transistor Ql, turns off the transistor Q2, and supplies a current to the first winding 1)a. is applied to impart an N pole to the first main magnetic pole 6a. When the S pole is detected, the transistor Q3 is turned off, the transistor Q1 is turned off, and the transistor Q2 is turned on.A current is passed through the second winding 1)b and the second main magnetic pole 6b is turned on.
Add a north pole to In this case, for example, in the former case, the first
When the main magnetic pole 6a is given an N pole, the second main magnetic pole 6b and each auxiliary magnetic pole? Each of a and 7b represents an S pole on the magnetic circuit, which is weaker than the first main magnetic pole 6a.

これは後者においても同様である。This also applies to the latter.

かかる電動機を平面的に見ると、回転子１の永久磁石２
はスキュー着磁した電気角１２０度にわたる部分の着磁
力がその他の部分の着磁力に比して大幅に低下し、上記
電気角１２０度の中心では異極が完全に相殺しあうこと
となる。従って通常のＮ極、Ｓ極として作用する範囲は
、スキュー着磁をしない異極境界からそれぞれ電気角１
２０度となる。このことにより、第１．第２主磁極６ａ
、６ｂに極性が付与されていないときは、永久磁石２の
いずれかの極の上記電気角１２０度の中心といずれかの
主磁極の中心が一致するよう回転子■が停止する。When such an electric motor is viewed from above, the permanent magnet 2 of the rotor 1
The magnetizing force of the skew-magnetized portion over 120 degrees of electrical angle is significantly lower than the magnetizing force of the other portions, and the different polarities completely cancel each other out at the center of the 120 degrees of electrical angle. Therefore, the range that acts as a normal N pole and S pole is 1 electrical angle from the different polarity boundary where no skew magnetization occurs.
It will be 20 degrees. Due to this, 1. Second main magnetic pole 6a
, 6b are not polarized, the rotor (2) is stopped so that the center of the electrical angle of 120 degrees of any of the poles of the permanent magnet 2 coincides with the center of any of the main magnetic poles.

（動作） 第４図（ａ）は、巻線１）に電流が流れていない安定停
止状態にある。この状態で電流切換回路に電流が供給さ
れると、磁気感応素子１２はＳ極を検出しているので、
巻線１）ｂに電流が流れて第２主磁極６ｂにＮ極が付与
され、その他の各種６ａ、？ａ、７ｂは弱いＳ極を示す
。従って永久磁石２のＮ極は第２主磁極６ｂのＮ極から
強い反発力、第１主磁極６ａと第２補助磁極７ｂから弱
い吸引力を受け、回転子１は矢符し方向に回転する。そ
して（ｂ）を経て（Ｃ）の状態まで回転すると、永久磁
石２のＳ極が第２主磁極６ｂのＮ極から強い吸引力を受
けて回転を続け（ｄ）の位置に達する。(Operation) FIG. 4(a) shows a stable stopped state in which no current flows through the winding 1). When current is supplied to the current switching circuit in this state, since the magnetic sensing element 12 has detected the S pole,
A current flows through the winding 1)b, giving the second main magnetic pole 6b an N pole, and other various types 6a, ? a and 7b indicate weak south poles. Therefore, the N pole of the permanent magnet 2 receives a strong repulsive force from the N pole of the second main magnetic pole 6b and a weak attractive force from the first main magnetic pole 6a and the second auxiliary magnetic pole 7b, causing the rotor 1 to rotate in the direction indicated by the arrow. . When the permanent magnet 2 rotates through state (b) to state (C), the S pole of the permanent magnet 2 receives a strong attractive force from the N pole of the second main magnetic pole 6b, and continues to rotate until it reaches the position shown in (d).

この状態で磁気感応素子１２はＮ極を検出して電流は巻
線１）ｂから巻線１）ａに切り換わり、第１主磁極６ａ
にＮ極が付与され、その他の各種６ｂ、７ａ、７ｂは弱
いＳ極を示す。従って上記と同様に反発力と吸引力を受
け、回転子１が回転を継続する。In this state, the magnetic sensing element 12 detects the north pole, and the current is switched from the winding 1)b to the winding 1)a, and the first main magnetic pole 6a
A north pole is given to , and the other various types 6b, 7a, and 7b show weak south poles. Therefore, the rotor 1 continues to rotate under the repulsion and attraction forces as described above.

なお、この実施例では固定子の外方に回転子を配設した
もので説明したが、固定子の内方に回転子を配設しても
よい。Although this embodiment has been described with the rotor disposed outside the stator, the rotor may be disposed inside the stator.

［発明の効果］ 本発明の無刷子電動機は、永久磁石を、電気角３６０度
の範囲で形成される２個の異極境界の一方が電気角１２
０度にわたってスキューした着磁とし、磁気感応素子を
、永久磁石の軸方向中央部の極性を検出するよう配設し
たから、一方向への自起動を可能にすることは勿論、永
久磁石の着磁状態を軸方向に２段にして異ならせる必要
がないので永久磁石の着磁が簡易なものとなり、また着
磁が細分化されないので電動機特性のばらつきが軽減で
きるものとなる。[Effects of the Invention] The brushless motor of the present invention has a permanent magnet in which one of two different polar boundaries formed in an electrical angle range of 360 degrees has an electrical angle of 12 degrees.
Since the magnetization is skewed by 0 degrees and the magnetic sensing element is arranged to detect the polarity of the axial center of the permanent magnet, it not only enables self-starting in one direction, but also allows the permanent magnet to be magnetized. Since there is no need to differentiate the magnetic state in two stages in the axial direction, the permanent magnet can be easily magnetized, and since the magnetization is not subdivided, variations in motor characteristics can be reduced.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は、本発明の一実施例を示す横断面図、第２図は
、その縦断面図、 第３図は、回転子の着磁状態と磁気感応素子の関係を示
す模式図、 第４図（ａ）（ｂ）（ｃ）（ｄ）は、動作説明図、第５
図は、一般的な電流切換回路の回路図、第６図（ａ）は
、従来例を示す横断面図、（ｂ）は、回転子の着磁状態
と磁気感応素子の関係を示す模式図。 １−回転子、２−永久磁石、３−カップ状ヨーク、４・
・−回転軸、５−固定子、６−主磁極、７−補助磁極、
９−・円筒状支持体、１）・−巻線、１２−・磁気感応
素子。 特許出願人　　松下電工株式会社 代理人弁理士　　　　竹光　敏九（ばか２名）第ｉｖ！
Ａ 第２図 第３図 第４図 （ａ）（ｂ） （Ｃ）（ｄ） 第５図 第６図 （ａ） （ｂ） 手続補正書 昭和６１年　２月２６日FIG. 1 is a cross-sectional view showing one embodiment of the present invention, FIG. 2 is a vertical cross-sectional view thereof, FIG. 3 is a schematic diagram showing the relationship between the magnetized state of the rotor and the magnetic sensing element, and FIG. 4(a)(b)(c)(d) are operation explanatory diagrams, fifth
The figure is a circuit diagram of a general current switching circuit, FIG. 6(a) is a cross-sectional view showing a conventional example, and FIG. 6(b) is a schematic diagram showing the relationship between the magnetized state of the rotor and the magnetic sensing element. . 1-rotor, 2-permanent magnet, 3-cup-shaped yoke, 4.
・-rotating shaft, 5-stator, 6-main magnetic pole, 7-auxiliary magnetic pole,
9--Cylindrical support, 1)--winding wire, 12--magnetic sensing element. Patent Applicant Matsushita Electric Works Co., Ltd. Representative Patent Attorney Toshikuru Takemitsu (2 Idiots) No. iv!
A Figure 2 Figure 3 Figure 4 (a) (b) (C) (d) Figure 5 Figure 6 (a) (b) Procedural amendment February 26, 1986

Claims (1)

【特許請求の範囲】[Claims] （１）周方向に異極が交互に着磁された円筒状の永久磁
石を有する回転子と、該回転子の極数に等しい主磁極と
補助磁極を交互に等間隔に有して各磁極面が回転子の永
久磁石に対し径方向に対面する固定子と、該固定子の主
磁極に巻装された巻線と、前記固定子に装着され前記回
転子の極性を検出して前記巻線の電流を切り換える磁気
感応素子とよりなる無刷子電動機において、前記永久磁
石を、電気角３６０度の範囲で形成される２個の異極境
界の一方が電気角１２０度にわたってスキューした着磁
とし、前記磁気感応素子を、前記永久磁石の軸方向中央
部の極性を検出するよう配設したことを特徴とする無刷
子電動機。(1) A rotor having a cylindrical permanent magnet with different poles alternately magnetized in the circumferential direction, and main magnetic poles and auxiliary magnetic poles equal to the number of poles of the rotor alternately arranged at equal intervals, each magnetic pole A stator whose surface faces the permanent magnet of the rotor in the radial direction, a winding wound around the main magnetic pole of the stator, and a winding mounted on the stator to detect the polarity of the rotor. In a brushless motor comprising a magnetic sensing element that switches a current in a line, the permanent magnet is magnetized such that one of two different polar boundaries formed in a range of 360 electrical degrees is skewed over 120 electrical degrees. . A brushless electric motor, characterized in that the magnetic sensing element is arranged to detect the polarity of the axially central portion of the permanent magnet.