JP3864227B2 - Repulsive magnetic levitation unit and transport system using this unit - Google Patents

Description

となる。ここで、μ0：真空の透磁率、μr1，μr2：磁性リング１１及び駆動用固定子７の比透磁率、Ｉ1，Ｉ2：磁路の長さ、Ｓ1，Ｓ2：断面積、ｘg：ギャップ長、Ｓ：ギャップの断面積とする。また、ギャップ中の磁束密度をＢg、巻数Ｎ、電流Ｉとすると、
【数２】

であるから、駆動用コイル６ａ、６ｂによる吸引力Ｆeは次式で表される。
【００３３】
【数３】

【００３４】
【表１】

【００３５】
この（３）式において、ギャップの２乗に反比例する傾向は、図５に示すＦＥＭ解析結果から確認でき、また（３）式は電流の２乗に比例するともいえる。
【００３６】
図６は、（３）式に表１に示す諸数値を代入して得られた結果である。ギャップが小さい場合での誤差は、磁気飽和の影響や断面積Ｓ1，Ｓ、磁路の長さｌ1が影響している。
【００３７】
次に、このようなユニット１に対する実験結果について説明する。
【００３８】
図７は、このユニット１による実験を行うための構成図を示す。物品を搬送するためには、ユニット１の回転軸４を非接触で運動させる必要がある。ここでは、基礎的なものとして、ユニット１の駆動用固定子７を磁性リング１１の直下に配置し、駆動用コイル６ａ（又は６ｂ）に単相の正弦波電流を加えたときの振動状態を測定する。
【００３９】
コイル駆動部８内の単相交流電源８ａからＶＶＶＦインバータ部８ｂを介して、駆動用コイル６ａ（６ｂ）にコイルに周波数の異なる電流を与える。この時の３通りのギャップ［小ギャップ（ｘg＝１．８mm）、中ギャップ（ｘg＝２．８mm）、大ギャップ（ｘg＝３．８mm）］について測定する。
【００４０】
回転軸４の中央側の浮上方向の振動をレーザ式変位センサ１２及びデジタルスコープ１３を用いて検出する。例えば、大ギャップ時の結果を図８及び図９に示す。ここで、図８（ａ）及び図９（ａ）は、それぞれ時間に対するギャップ幅の変化を示し、図８（ｂ）及び図９（ｂ）は、それぞれ励磁周波数に対する振動成分を示している。それぞれに電流値約０．５Ａでの測定結果であり、励磁周波数のみを変化させた場合である。前述した（３）式は、以下のように表せる。
【００４１】
【数４】

【００４２】
（４）式より、実行値Ｉe、周波数ｆの交流電流印加時では、
【数５】

となり、駆動用コイル６ａ（６ｂ）の吸引力は、励磁周波数の２倍で生じている。図８（ｂ）に示すように、１０Ｈｚ付近での振動が顕著であるが、図９（ｂ）に示した例では、１２０Ｈｚ付近での振動は見られず、２５Ｈｚ付近の振動成分が主となる。この傾向は、励磁周波数２０Ｈｚ以上では顕著に現れ、この周波数は次式を満たす回転軸４の固有振動数であることがわかる。
【００４３】
【数６】

【００４４】
図１０は、励磁電流に対するギャップの平均値との関係を示している。ここでは、励磁周波数は５〜１２０Ｈｚでの全てのデータが含まれている。物品が回転軸４上を通過する場合、その荷重によって回転軸４が沈み込むことを考慮する必要がある。そこで前記の３通りのギャップで測定する。この図１０を参照すれば、初期ギャップから電流の増加に伴い、ギャップが減少し、電流値がある値を超えると回転軸４（磁性リング１１）と駆動用コイル６ａ、６ｂとが吸着してしまうことがわかる。
【００４５】
上記（４）式において、駆動用コイル６ａ、６ｂでの吸引力を一定とすると、コイルを流れる電流とギャップには比例関係があり、最大電流値における図中の点線で示す直線を描くことができる。この直線は、搬送される物品の全質量が１本の回転軸４に垂直にかかるとした場合、永久磁石部（ステータ磁石９ａ、９ｂ及びロータ磁石１０ａ、１０ｂ）の反発力による静たわみを初期ギャップから差し引いた値を考慮して電流を印加するための指標となる。ここでは、広いダイナミックレンジを考慮して、回転軸４側と駆動用コイル６ａ、６ｂ（駆動用固定子７）側の距離を、ステータ磁石９ａ、９ｂとロータ磁石１０ａ、１０ｂとの間のギャップとしては４mm程度が好ましい。
【００４６】
搬送される物品によって、最適な電源周波数は異なる。電源周波数は、例えば３相交流のような交流電流であり、前述したように回転軸４の固有振動数で力が発生する様になればよく、例えば、電源周波数の２倍で発生してれば、固有周波数の１／２の周波数が好ましい。
【００４７】
また、このユニット１は、例えば、パルス電流やノコギリ波のような交流電流以外でも駆動することが可能である。以下の説明では、駆動用電流を交流電流を例として説明する。
【００４８】
このユニット１は、回転軸４を搬送される物品との摩擦力を利用することによって搬送させているため、単なる交流波形の駆動電流の場合には、回転軸４が楕円軌道を描くように振動させることが必要である。つまり、超音波モータと同様な駆動方式である。また、パルス電流でユニット１を駆動させる場合には、回転軸４の振動の行きと戻りの振動速度に違いをつけて、物品を押し出すように動作をさせることも可能である。
【００４９】
以上説明したように、このユニット１は、駆動用コイル６ａ、６ｂに交流電流（パルス電流）を与えることにより、回転軸４が浮上方向に振動し、回転軸上を物品が搬送される場合には、回転軸４は振動しながら沈み込み、物品の移動で滑らかに回転する。磁性リング１１が回転しても回転位置による斑がないため、回転による駆動力の差は発生しない。このようなユニットを複数個用いて、与える交流電流の位相を操作して、移動磁界を発生させることで物品の移動が可能となる。
【００５０】
次に、本発明に係る第１の実施形態として、前述したユニット１を用いた搬送システムについて説明する。図１１（ｂ）は、複数台のユニット１ａ〜１ｎを配列し、物品を搬送する搬送システムの構成例を示している。
【００５１】
この搬送システムは図１１（ａ）に示すように、ベース部２１上に複数のユニット１ａ〜１ｎが配置され、それぞれを駆動する駆動部２２が接続されている。この駆動部２２は、パーソナルコンピュータ等からなる制御部２３により制御され、各ユニット１ａ〜１ｎの駆動用コイル６ａ、６ｂに交流電流を供給して駆動する。
【００５２】
この駆動部２２は、一般的な３相交流等の交流電流を供給する電源部２４と、制御部２３により制御されて、前述したように回転軸４の固有振動数に基づき、電源部からの交流電流の位相を操作して、好適な周波数に変換する駆動用電流変換部２５と、この駆動用電流変換部２５からの駆動用電流を増幅して、各ユニット１ａ〜１ｎを駆動させる。
【００５３】
この搬送システムにおいては、全ユニット１ａ〜１ｎが駆動する状態を維持させて物品２７を搬送させ、末端のユニット１ｎには、搬送ストッパ部２８を設ける。この搬送ストッパ部２８は、搬送されている物品２７が当て付けられるため、物品２７に損傷を与えないように、衝撃を吸収する部材や機構を設けている。
【００５４】
以上のような第１の実施形態の搬送システムは、回転軸（中心軸）４が浮上しているため機械的な接触する箇所がごく僅かであり、機械的な摩擦や磨耗の問題や振動、騒音の問題が極めて少ない。特に、オイルのような潤滑剤を使用しないため、搬送システムを設置された周辺に汚れや臭い等の悪影響を与えず、摩擦等による金属ダストが発生せず、衛生的な環境下での使用が可能である。例えば、食料品加工や薬剤の生産等の搬送システムとして用いることができる。
【００５５】
次に、第２の実施形態に係る搬送システムについて説明する。
本実施形態は、前述したユニット１と、図１２に示すようなユニット１から駆動用固定子７、駆動用コイル６ａ、６ｂ及び磁性リング１１を除いて、駆動部を有していない受動ユニット３１を組み合わせて搬送システムを構築するものである。この受動ユニット３１において、図１と同等な構成部位には同じ参照符号を付して、その詳細な説明は省略する。
【００５６】
この受動ユニット３１は、前述した反発形磁気浮上ユニット１と同様に、ベース部２と、ベース部２の両端に設けられたストッパ部３ａ、３ｂと、回転軸４を反発する磁力により浮上させた状態で軸支するステータ磁石台５ａ、５ｂとで構成される。また、回転軸３２の中央部分には、前述したと同等な磁性リング１１又は、滑り止めとして機能する部材３３により側面外周を覆うように設けられる。これは、搬送する物品との間に摩擦を生じさせるために設けている。
【００５７】
このような受動ユニット３１とユニット１とを例えば、１台のユニット１と４台の受動ユニット３１の割合で組み合わせて、図１３に示すように搬送システムを構築する。
【００５８】
この搬送システムでは、例えば、４台おきに駆動するユニット１が配置され、ユニット１ａ〜１ｎは、制御部２３で制御される駆動部２３により駆動される。これらのユニット１ａ〜１ｎの駆動力により物品を送り、受動ユニット３１ａ〜３１ｎが物品の搬送状態を維持する。受動ユニット３１ａ〜３１ｎは、回転軸３４が浮上されており、機械的な摩擦がないため、移動する物品が減速されにくい特徴がある。
【００５９】
第２の実施形態の搬送システムは、全ユニット１ａ〜１ｎを駆動状態にして物品を搬送する第１の実施形態に比べて、駆動させるユニット数が１／５で済み、消費電力が抑制できる。また、受動ユニット３１ａ〜３１ｎは駆動部が無く、ユニットよりも簡素な構成であるため、搬送システムのコストが安価となる。
【００６０】
尚、本実施形態では、１台のユニットに対して４台の受動ユニットを配置したが、これに限定されるものではなく、搬送する物品の大きさに応じて適宜、変更することは容易にできる。
【００６１】
次に、第３の実施形態に係る搬送システムについて説明する。
この第３の実施形態は図１４に示すように、前述した第１の実施形態と同様な搬送システムにおいて、ユニット１ａ〜１ｎの回転軸４上に物品２７があるか否かを検出するセンサ４１を複数のユニット１に設けている。この例では、４個のユニット１ａ〜１ｄ間に赤外光を利用した４個のセンサ４１ａ〜４１ｄをそれぞれ設けてある。勿論、このセンサ配置に限定されるものではない。
【００６２】
これは、前述した第１の実施形態では、全ユニット１ａ〜１ｎを駆動状態としたため、消費電力が大きい。これに対して、第２の実施形態は、駆動部を有していない受動ユニット３１ａ〜３１ｎをユニット１ａ〜１ｎと適宜組み合わせて配置して消費電力低下を実現したが、一度、受動ユニット３１ａ〜３１ｎとユニット１ａ〜１ｎが配置されると、物品２７の大きさが変化しても対応できなかった。
【００６３】
本実施形態では、搬送させる物品２７の大きさを検出し、その大きさに合わせて駆動するユニットを選択し、これらのユニットのみを駆動して、選択されなかったユニットは、第２実施形態の受動ユニットと同様に駆動せずに用いる。
【００６４】
この搬送システムでは、搬送される物品２７がユニット１ａ〜１ｆに置かれる（又は、通過する）と、センサ４１ａ〜４１ｃが物品の大きさを検出し、この検出結果は、制御部２３へ送出される。制御部２３では、物品２７の大きさにより駆動するユニットを選択し、選択されたユニットのみが駆動されるように、駆動部２２へ指示する。駆動部２２は、この指示を受けて、駆動させるユニットの駆動用コイル６ａ、６ｂへ交流電流を供給する。
【００６５】
次に、第４の実施形態に係る搬送システムについて説明する。
前述した第３の実施形態では、ユニット１ａ〜１ｎの前方側のみに複数個のセンサ４１を設けて、搬送する物品の大きさを測定したが、本実施形態では図１５に示すように、さらにユニット全体に亘って、数個おきに位置センサ４２ａ〜４２ｎを配置して、ユニット１ａ〜１ｎを複数のブロックＡ〜Ｎに分割する。
【００６６】
この構成によれば、最初に搬送する物品の大きさを検出して、駆動するユニットが選択される。その後、これらのユニットの駆動により、物品が移動していくと、その通過に伴い位置センサ４２ａ〜４２ｎが順次オン・オフして、物品の現在の位置を検出することができる。この検出結果を利用して、例えば、オンした位置センサ４１の前方２ブロック前のユニットへ交流電流を供給を開始して駆動させ、オンした位置センサ４１のブロックのユニットへの駆動電流の供給を停止させる。これらの位置センサがオンするタイミングを計測することにより、物品の移動する状態を推測して、好適するタイミングでユニットを駆動させて、通過したと共に駆動電流の供給を停止させることもできる。
【００６７】
従って、本実施形態によれば、間隔をあけてユニット間に配置された位置センサを用いて、電流供給や停止を制御することにより、無駄な電流消費を抑制することができる。このような制御は搬送ラインが長くなるほど有益である。
【００６８】
以上説明したように、各実施形態の反発形浮上ユニットは、回転軸の浮上により回転に対する機械的な接触が無く、摩擦や磨耗を無くし、また振動、騒音についても極めて問題が無く、衛生的な環境下での使用に好適する。また、駆動部と駆動部を有さないユニットを組み合わせて構成することにより、消費電力の抑制を行うことができる。
【００６９】
このようなユニットと、駆動部を除く構成のユニットとを組み合わせて搬送ラインに組み込むことにより、制御部や駆動用電磁石等の構成部位の大幅な縮小を可能にして、低コスト化を実現し、且つ省消費電力をも実現する。
【００７０】
また、本実施形態の搬送システムでは、直線的な搬送ラインを例としているが勿論、この例に限定されるものではない。例えば、搬送ライン（主ライン）途中に分岐するようにユニットを配置した分岐ラインを設け、その分岐部分に、制御部に制御されて上下移動可能な搬送ストッパ部を設け、さらに、その主ライン上方から分岐ライン上方に移動するアームを設ける。搬送されてくる物品を搬送ストッパ部を上昇させ当て付けて停止させる。アームにより物品を分岐ライン側のユニット上に移動させて、以降、分岐ラインのユニットを駆動させることにより、分岐ラインを有する搬送システムを構築することができる。
【００７１】
さらに、ユニットを曲線的にカーブするように配置し、そのカーブ部分のユニットを物品が外に飛び出さないようにバンクを持たせるように配置することにより、直線だけではなく、曲線の搬送ラインを構築することもできる。
【００７２】
【発明の効果】
以上詳述したように本発明によれば、反発する磁力により浮上されて回転可能に軸支され、電磁場により浮上方向に振動する回転軸を有する反発形磁気浮上ユニット及びこのユニットを複数配列して、上記回転軸により物品を搬送する反発形磁気浮上ユニット及びこのユニットを用いた搬送システムを提供することができる。
【図面の簡単な説明】
【図１】 本発明の反発形浮上ユニットの外観構成を示す図である。
【図２】 永久磁石部（ステータ磁石及びロータ磁石）の分割要素と磁束密度分布を示す図である。
【図３】 電磁石部（駆動用コイル及び磁性リング）の分割要素と磁束密度分布を示す図である。
【図４】 永久磁石部における位置に対する反発力（反発力解析結果）を示す図である。
【図５】 ギャップに対する吸引力の関係（ＦＥＭ解析結果）を示す図である。
【図６】 （３）式へ表３で示す諸数値を代入して得られた結果を示す図である。
【図７】 本発明の反発形浮上ユニットを実験するための構成を示す図である。
【図８】 時間に対するギャップ幅の変化と、励磁周波数に対する振動成分を示す図である。
【図９】 時間に対するギャップ幅の変化と、励磁周波数に対する振動成分を示す図である。
【図１０】 励磁電流に対するギャップの平均値との関係を示す図である。
【図１１】 第１の実施形態として、本発明の反発形浮上ユニットを用いて構成した搬送システムの概念的な構成を示す図である。
【図１２】 第２の実施形態に係る搬送システムに用いられる反発形浮上受動ユニットの外観構成を示す図である。
【図１３】 第２の実施形態となる搬送システムの概念的な構成を示す図である。
【図１４】 第３の実施形態となる搬送システムの概念的な構成を示す図である。
【図１５】 第４の実施形態となる搬送システムの概念的な構成を示す図である。
【符号の説明】
１…反発形磁気浮上ユニット（ユニット）
２…ベース部
３ａ、３ｂ…ストッパ部
４…回転軸（中心軸）
５ａ、５ｂ…ステータ磁石台
６ａ、６ｂ…駆動用コイル
７…駆動用固定子
８…コイル駆動部
９ａ、９ｂ…ステータ磁石
１０ａ、１０ｂ…ロータ磁石
１１…磁性リング[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transfer device including a permanent magnet repulsive magnetic bearing that uses the magnetic force of a magnet.
[0002]
[Prior art]
Generally, when a part is rotated or rotated, the part is supported using a bearing or the like to achieve rotation. However, in the configuration using a bearing or the like, when the rotation supported member requires high rotation, or the rotation supported portion is small and light, mechanical friction, loss of rotational energy, etc. Is a problem. In order to solve this problem, a technique is known in which a magnetic field is formed by a magnet or the like and the part is floated and maintained in the air so that the part is magnetically levitated by attraction or repulsion.
[0003]
For example, Patent Documents 1 and 2 disclose an optical deflection scanning device having a repulsive magnetic levitation shaft. In these Patent Documents 1 and 2, magnets are arranged so as to repel each other, and the state where the rotor serving as the rotating shaft is floated in the air is maintained. These drive motors are provided to realize rotation. By using this configuration, downsizing is realized.
[0004]
In addition, as conveyors for articles, a belt conveyor device that moves a belt with at least two or more rollers interposed therebetween, a conveyor in which a large number of rotatable rollers are arranged, and the like are known.
[0005]
[Patent Document 1]
JP 2002-81455 A
[0006]
[Patent Document 2]
JP 2002-365581 A
[0007]
[Problems to be solved by the invention]
Also in the rollers of the conveyor belt conveyor device described above, the rotating shaft is mechanically supported by bearings, etc., and as the number of rollers increases, problems such as mechanical friction, wear, vibration and noise occur. To do.
[0008]
This bearing requires a lubricant in order to obtain smooth rotation, and stains, odors and the like due to the lubricant are generated. For this reason, it cannot be said that it is suitable for the conveyance of a medicine or a medical product in a food field or a medical field in a food factory that is highly demanded in terms of hygiene.
[0009]
Therefore, the present invention provides a repulsive magnetic levitation unit having a rotating shaft that is levitated by a repelling magnetic force and is rotatably supported and vibrates in the levitating direction by an electromagnetic field, and a plurality of these units are arranged, and an article is disposed by the rotating shaft. It is an object of the present invention to provide a repulsive magnetic levitation unit for conveyance and a conveyance system using the unit.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a base provided with an electromagnet, a rotary shaft provided with an annular first magnet on both side surfaces of the shaft, and the first magnet fixed to the base. A second magnet for allowing the rotary shaft to float in a state of being repelled with a gap from the entire outer circumference of the magnet, and an annular magnetic body provided on a side surface of the rotary shaft facing the electromagnet, When an alternating current is supplied to the electromagnet, an attractive force corresponding to the frequency is generated between the magnetic body and the alternating current, and the rotating shaft is vibrated to move the mounted article. Provide units.
[0011]
Further, the base provided with the electromagnet, the rotating shaft provided with the annular first magnet on the side surfaces on both ends of the shaft, and fixed to the base, repelled with a clearance from all the side surfaces of the first magnet. A plurality of repulsions configured by a second magnet that is inserted in a floating state by the rotating shaft and an annular magnetic body provided on a side surface of the rotating shaft facing the electromagnet, and arranged as a conveyance path A magnetic levitation unit, and a drive unit that supplies an alternating current to the electromagnet of the repulsive magnetic levitation unit so as to generate a force at the natural frequency of the rotary shaft and applies vibration in the levitation direction to the rotary shaft Provided is a transport system in which the article is moved and transported in one direction along the transport path when the article is placed on the rotating shaft that is provided and vibrates.
[0012]
The repulsive magnetic levitation unit configured as described above rotates when the rotating shaft vibrates in the flying direction by applying an alternating current (or pulsed current) to the electromagnet, and an article is conveyed on the rotating shaft. The shaft sinks while vibrating, is pushed up by the repulsive force of the first magnet and the second magnet, moves the article, and rotates smoothly.
[0013]
Further, the transport system forms a transport path by arranging a plurality of the repulsive magnetic levitation units, and the rotating shaft that vibrates has no mechanical contact, rotates along with the movement of the article, and moves along the transport path. The article is conveyed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is an external configuration diagram of a repulsive floating unit according to the present invention, and the configuration and operating principle will be described.
By arranging a plurality of repulsive magnetic levitation units (hereinafter referred to as units) 1 of the present embodiment, a transport system for transporting articles can be constructed as will be described later. First, this unit will be described.
[0016]
The main structure of this unit 1 is a base part 2, stopper parts 3a and 3b provided at both ends of the base part 2, and a stator provided on the base part 2 and pivotally supported with the central shaft 4 levitated. The magnet bases 5a and 5b, the driving coils 6a and 6b made of electromagnets for vibrating the floating central shaft 4, and the U-shaped shape, and the driving coils 6a and 6b are fitted into the convex portions on both sides, respectively. It comprises a driving stator (iron core) 7 fixed on the base portion 2 and a coil driving portion 8 that drives (vibrates) the driving coils 6a and 6b by applying a driving current.
[0017]
Specifically, the base portion 2 is formed of a metal material such as an aluminum alloy, for example. In the present embodiment, a rectangle is taken as an example, but the size and shape can be changed as appropriate according to the article to be conveyed.
[0018]
The stopper portion 3 guides the rotation shaft (center shaft) 4 so as not to come off from stator magnet bases 5a and 5b described later. The stopper portion 3 is made of, for example, a metal material such as brass, and a resin material, for example, a polyimide film is attached to the side in contact with both ends of the rotating rotating shaft 4 so that friction at the time of contact is reduced. ing. Of course, you may shape | mold the whole stopper part with resin. Further, here, at the time of guiding by the stopper portion 3, one end of the rotating shaft 4 is configured to be in contact with each other so that the rotation operation is not lost as much as possible.
[0019]
The stator magnet bases 5a and 5b are made of resin, for example, acrylic, and are fitted with annular stator magnets 9a and 9b, respectively. The inner sides of the stator magnets 9a and 9b are opened in a circular shape so as to be hollow.
[0020]
The rotating shaft 4 has a column shape, and both ends are formed in a hemispherical shape. Since the rotating shaft 4 rotates in a floating state, a light and hard non-magnetic material is suitable, and when the both ends of the shaft are in contact with the surface of the stopper portion 3, the hemispherical shape is brought into contact to reduce friction. Is formed.
[0021]
The rotating shaft 4 penetrates (penetrates) through the stator magnets 9a and 9b, and an annular rotor magnet 10a having a magnetic field repelling the stator magnets 9a and 9b on the side surface of the shaft facing the stator magnets 9a and 9b. 10b are fitted. The stator magnets 9a and 9b and the rotor magnets 10a and 10b are preferably magnets having a magnetic pole in the axial direction and strong coercive force. For example, NdFeB magnets are suitable for neodye materials.
[0022]
In this configuration, the stator magnets 9a and 9b and the rotor magnets 10a and 10b are repelled and positioned with a predetermined gap (gap) therebetween. Therefore, the rotating shaft 4 is passively supported in the radial direction of the rotating shaft in a floating state, and stable in the unstable axial direction by bringing one end of the rotating shaft 4 into contact with the stopper portion 3. I am letting.
[0023]
Further, an annular magnetic ring 11 made of a magnetic material such as iron SS41 is provided on the center side of the rotating shaft 4 so as to cover the side surface facing the driving coils 6a and 6b. The driving coils 6a and 6b are electromagnets formed by winding copper conductors into a disk shape, and each is fitted into a driving stator 7 made of a silicon steel plate and driven by a driving current supplied from a coil driving unit 8. As will be described later, the rotating shaft 4 is stabilized in the radial direction, and vibration is applied in the flying direction.
[0024]
In this unit 1, if the base material 2, the stopper parts 3a, 3b, and the stator magnet bases 5a, 5b are made of metal, other than non-magnetic stainless steel materials (for example, austenitic, SUS304, etc.) As a material other than metal, resin, ceramics, etc. can be applied as long as they are nonmagnetic materials.
[0025]
The driving principle of the repulsive levitation unit configured as described above will be described.
[0026]
If the unit 1 is position-controlled in a state where the rotary shaft 4 is levitated, a stable system can be obtained, and the configuration based on the translational motion limitation in the unstable axis direction is the basis.
[0027]
Specifically, the unit 1 basically has the rotating shaft 4 levitated by a permanent magnet portion (region A) composed of two sets of rotor magnets 10a and 10b and stator magnets 9a and 9b, and the magnetic ring of the rotating shaft 4 11 can be realized by an electromagnet portion (region B) that vibrates up and down by the driving coils 6a and 6b.
[0028]
First, repulsive force / attraction force analysis will be described.
The three-dimensional magnetic field analysis is performed by the finite element method, and the repulsive force characteristic in the permanent magnet part and the attractive force characteristic in the stator side electromagnet are investigated. This analysis is performed on the regions A and B shown in FIG. 1 and is analyzed as being magnetically independent from each other. 2 (a) and 2 (b) show the split elements and the magnetic flux density distribution of the permanent magnet portion that becomes the region A, and FIGS. 3 (a) and 3 (b) show the electromagnet portion that becomes the region B. The split element and magnetic flux density distribution are shown. However, in these analysis models, the air layer is not displayed and a sufficiently wide area is taken into consideration.
[0029]
In this analysis, analysis is performed using finite element method analysis software (for example, MagNet 6 (trade name)). The characteristics of the repulsive force and the attractive force are obtained from the result of the acting force when the position of the element on the rotating shaft 4 side is three-dimensionally changed. The analysis specifications at this time are shown in Table 1 described later.
[0030]
FIG. 4 shows a repulsive force analysis result in the permanent magnet portion (region 1).
[0031]
From this result, it can be seen that the radial direction has positive rigidity and the axial direction has negative rigidity, and the magnitudes are about kx = 1416 N / m and kz = 2950 N / m at the zero position, respectively.
Further, the load resistance in one unit 1 (the weight with which the rotor magnets 10a and 10b and the stator magnets 9a and 9b do not contact when an article is placed on the rotating shaft 1) is considered only when two sets of permanent magnet portions are considered. The maximum is about 18N (at 4mm displacement).
[0032]
FIG. 5 shows an analysis result of the attractive force in the electromagnet part (region 2). The excitation current here is a direct current of 0.2 to 1.0 A, and shows the relationship between the gap and the attractive force. Here, when the attraction force of the electromagnet is expressed using a mathematical formula, the magnetic resistance value of the entire magnetic circuit is as follows under the condition that the magnetic saturation and hysteresis of the electromagnet are not considered.
[Expression 1]

It becomes. Here, μ0: permeability of vacuum, μr1, μr2: relative permeability of magnetic ring 11 and driving stator 7, I1, I2: length of magnetic path, S1, S2: cross-sectional area, xg: gap length, S: The cross-sectional area of the gap. If the magnetic flux density in the gap is Bg, the number of turns N, and the current I,
[Expression 2]

Therefore, the attractive force Fe by the drive coils 6a and 6b is expressed by the following equation.
[0033]
[Equation 3]

[0034]
[Table 1]

[0035]
In this equation (3), the tendency inversely proportional to the square of the gap can be confirmed from the FEM analysis result shown in FIG. 5, and it can be said that equation (3) is proportional to the square of the current.
[0036]
FIG. 6 shows the results obtained by substituting the numerical values shown in Table 1 into equation (3). The error in the case where the gap is small is affected by the influence of magnetic saturation, the cross-sectional areas S1 and S, and the length l1 of the magnetic path.
[0037]
Next, experimental results for such a unit 1 will be described.
[0038]
FIG. 7 shows a configuration diagram for conducting an experiment using the unit 1. In order to convey the article, it is necessary to move the rotating shaft 4 of the unit 1 in a non-contact manner. Here, as a basic one, the driving stator 7 of the unit 1 is arranged directly below the magnetic ring 11 and the vibration state when a single-phase sine wave current is applied to the driving coil 6a (or 6b) is shown. taking measurement.
[0039]
A single-phase AC power supply 8a in the coil drive unit 8 is supplied with currents having different frequencies to the drive coil 6a (6b) via the VVVF inverter unit 8b. Three types of gaps [small gap (xg = 1.8 mm), medium gap (xg = 2.8 mm), large gap (xg = 3.8 mm)] are measured.
[0040]
The vibration in the floating direction at the center side of the rotating shaft 4 is detected using a laser displacement sensor 12 and a digital scope 13. For example, the results for a large gap are shown in FIGS. Here, FIGS. 8A and 9A show changes in the gap width with respect to time, and FIGS. 8B and 9B show vibration components with respect to the excitation frequency. Each is a measurement result at a current value of about 0.5 A, and is a case where only the excitation frequency is changed. The above-described equation (3) can be expressed as follows.
[0041]
[Expression 4]

[0042]
From the equation (4), when an alternating current having an effective value Ie and a frequency f is applied,
[Equation 5]

Thus, the attractive force of the drive coil 6a (6b) is generated at twice the excitation frequency. As shown in FIG. 8B, the vibration near 10 Hz is remarkable, but in the example shown in FIG. 9B, the vibration near 120 Hz is not seen, and the vibration component near 25 Hz is mainly. Become. This tendency appears remarkably at an excitation frequency of 20 Hz or higher, and it can be seen that this frequency is the natural frequency of the rotating shaft 4 that satisfies the following equation.
[0043]
[Formula 6]

[0044]
FIG. 10 shows the relationship with the average value of the gap with respect to the excitation current. Here, the excitation frequency includes all data at 5 to 120 Hz. When the article passes on the rotating shaft 4, it is necessary to consider that the rotating shaft 4 sinks due to the load. Therefore, measurement is performed with the above three gaps. Referring to FIG. 10, as the current increases from the initial gap, the gap decreases. When the current value exceeds a certain value, the rotating shaft 4 (magnetic ring 11) and the driving coils 6a and 6b are attracted. I understand that.
[0045]
In the above equation (4), if the attractive force in the driving coils 6a and 6b is constant, the current flowing through the coil and the gap are proportional to each other, and a straight line indicated by a dotted line in the figure at the maximum current value can be drawn. it can. If the total mass of the article to be conveyed is applied perpendicularly to one rotating shaft 4, this straight line initially causes the static deflection due to the repulsive force of the permanent magnet parts (stator magnets 9 a and 9 b and rotor magnets 10 a and 10 b). It becomes an index for applying a current in consideration of a value subtracted from the gap. Here, in consideration of a wide dynamic range, the distance between the rotating shaft 4 side and the driving coils 6a and 6b (driving stator 7) side is defined as the gap between the stator magnets 9a and 9b and the rotor magnets 10a and 10b. Is preferably about 4 mm.
[0046]
The optimum power supply frequency varies depending on the article to be conveyed. The power supply frequency is an alternating current such as a three-phase alternating current, and as long as the force is generated at the natural frequency of the rotating shaft 4 as described above, for example, it is generated at twice the power supply frequency. For example, a frequency that is 1/2 of the natural frequency is preferable.
[0047]
Further, the unit 1 can be driven by other than an alternating current such as a pulse current or a sawtooth wave, for example. In the following description, the drive current will be described by taking an alternating current as an example.
[0048]
Since the unit 1 conveys the rotating shaft 4 by utilizing the frictional force with the article to be conveyed, in the case of a drive current having a simple AC waveform, the rotating shaft 4 vibrates so as to draw an elliptical orbit. It is necessary to make it. That is, it is the same drive system as the ultrasonic motor. Further, when the unit 1 is driven by a pulse current, the operation can be performed to push out the article by making a difference between the vibration speed of the rotating shaft 4 and the vibration speed of the return.
[0049]
As described above, the unit 1 applies the alternating current (pulse current) to the driving coils 6a and 6b, so that the rotating shaft 4 vibrates in the flying direction, and the article is conveyed on the rotating shaft. The rotary shaft 4 sinks while vibrating and rotates smoothly with the movement of the article. Even if the magnetic ring 11 rotates, there is no unevenness due to the rotational position, so that a difference in driving force due to the rotation does not occur. By using a plurality of such units and operating the phase of the alternating current to be applied to generate a moving magnetic field, the article can be moved.
[0050]
Next, a transport system using the above-described unit 1 will be described as a first embodiment according to the present invention. FIG. 11B shows a configuration example of a transport system in which a plurality of units 1a to 1n are arranged to transport an article.
[0051]
As shown in FIG. 11A, in this transport system, a plurality of units 1a to 1n are arranged on a base unit 21, and a driving unit 22 for driving each unit is connected. This drive part 22 is controlled by the control part 23 which consists of personal computers etc., supplies an alternating current to the drive coils 6a and 6b of each unit 1a-1n, and drives.
[0052]
The driving unit 22 is controlled by a power source unit 24 that supplies an alternating current such as a general three-phase alternating current and a control unit 23, and based on the natural frequency of the rotating shaft 4 as described above, The drive current converter 25 that converts the phase of the alternating current into a suitable frequency and the drive current from the drive current converter 25 are amplified to drive the units 1a to 1n.
[0053]
In this transport system, the articles 27 are transported while maintaining the state in which all the units 1a to 1n are driven, and the transport unit 28 is provided in the terminal unit 1n. The conveyance stopper portion 28 is provided with a member and a mechanism for absorbing an impact so as not to damage the article 27 because the article 27 being conveyed is applied thereto.
[0054]
In the transport system according to the first embodiment as described above, since the rotating shaft (center shaft) 4 is floating, there are very few mechanical contact points, problems of mechanical friction and wear, vibration, There are very few noise problems. In particular, since lubricants such as oil are not used, there is no adverse effect such as dirt or odor around the transport system installed, metal dust due to friction is not generated, and it can be used in a hygienic environment. Is possible. For example, it can be used as a transport system for food processing, drug production, and the like.
[0055]
Next, a transport system according to the second embodiment will be described.
In the present embodiment, the above-described unit 1 and the passive unit 31 having no driving unit except for the driving stator 7, the driving coils 6a and 6b, and the magnetic ring 11 from the unit 1 as shown in FIG. Are combined to construct a transport system. In this passive unit 31, the same reference numerals are assigned to components equivalent to those in FIG. 1, and detailed description thereof is omitted.
[0056]
In the same manner as the repulsive magnetic levitation unit 1 described above, the passive unit 31 floats the base portion 2, the stopper portions 3 a and 3 b provided at both ends of the base portion 2, and the rotating shaft 4 by the repulsive magnetic force. It is comprised with the stator magnet stand 5a, 5b pivotally supported in a state. Further, a central portion of the rotating shaft 32 is provided so as to cover the outer periphery of the side surface with the magnetic ring 11 equivalent to that described above or the member 33 that functions as a slip stopper. This is provided in order to generate friction between the articles to be conveyed.
[0057]
Such a passive unit 31 and the unit 1 are combined at a ratio of one unit 1 and four passive units 31, for example, to construct a transport system as shown in FIG.
[0058]
In this transport system, for example, every four units 1 are arranged, and the units 1 a to 1 n are driven by the drive unit 23 controlled by the control unit 23. The articles are fed by the driving force of these units 1a to 1n, and the passive units 31a to 31n maintain the conveyance state of the articles. The passive units 31a to 31n have a feature that the rotating shaft 34 is levitated and there is no mechanical friction, so that moving articles are difficult to decelerate.
[0059]
The transport system of the second embodiment requires only 1/5 the number of units to be driven and can suppress power consumption, compared to the first embodiment in which all units 1a to 1n are driven to transport articles. Further, since the passive units 31a to 31n have no drive unit and have a simpler configuration than the unit, the cost of the transport system is reduced.
[0060]
In this embodiment, four passive units are arranged for one unit. However, the present invention is not limited to this, and can be easily changed as appropriate according to the size of the article to be conveyed. it can.
[0061]
Next, a transport system according to the third embodiment will be described.
As shown in FIG. 14, in the third embodiment, a sensor 41 that detects whether or not an article 27 is present on the rotary shaft 4 of each of the units 1a to 1n in the same transport system as that of the first embodiment described above. Are provided in a plurality of units 1. In this example, four sensors 41a to 41d using infrared light are provided between the four units 1a to 1d, respectively. Of course, the sensor arrangement is not limited to this.
[0062]
In the first embodiment described above, all the units 1a to 1n are in the driving state, and thus power consumption is large. On the other hand, in the second embodiment, the passive units 31a to 31n that do not have the drive unit are arranged in appropriate combination with the units 1a to 1n to realize a reduction in power consumption, but once the passive units 31a to 31n are realized. When 31n and the units 1a to 1n are disposed, the size of the article 27 cannot be changed.
[0063]
In the present embodiment, the size of the article 27 to be conveyed is detected, a unit to be driven is selected in accordance with the size, and only these units are driven. It is used without being driven like the passive unit.
[0064]
In this conveyance system, when the article 27 to be conveyed is placed (or passes) in the units 1a to 1f, the sensors 41a to 41c detect the size of the article, and the detection result is sent to the control unit 23. The The control unit 23 selects a unit to be driven according to the size of the article 27 and instructs the drive unit 22 to drive only the selected unit. The drive unit 22 receives this instruction and supplies an alternating current to the drive coils 6a and 6b of the unit to be driven.
[0065]
Next, a transport system according to the fourth embodiment will be described.
In the third embodiment described above, a plurality of sensors 41 are provided only on the front side of the units 1a to 1n, and the size of the article to be conveyed is measured. In this embodiment, as shown in FIG. Position sensors 42a to 42n are arranged every several units throughout the unit, and units 1a to 1n are divided into a plurality of blocks A to N.
[0066]
According to this configuration, the unit to be driven is selected by detecting the size of the article to be conveyed first. After that, as the article moves by driving these units, the position sensors 42a to 42n are sequentially turned on / off along with the passage, and the current position of the article can be detected. Using this detection result, for example, supply of alternating current to the unit two blocks before the position sensor 41 turned on is started and driven, and the drive current is supplied to the unit of the block of the position sensor 41 turned on. Stop. By measuring the timing when these position sensors are turned on, it is possible to estimate the state of movement of the article, drive the unit at a suitable timing, and stop the supply of the drive current as well as passing.
[0067]
Therefore, according to the present embodiment, wasteful current consumption can be suppressed by controlling the current supply and the stop using the position sensors arranged between the units at intervals. Such control is more beneficial as the transport line becomes longer.
[0068]
As described above, the repulsive levitation unit of each embodiment has no mechanical contact with rotation due to the levitation of the rotating shaft, eliminates friction and wear, and has no problems with vibration and noise, and is hygienic. Suitable for use in the environment. Further, the power consumption can be suppressed by combining the drive unit and the unit that does not have the drive unit.
[0069]
By combining such a unit and a unit having a configuration excluding the drive unit into the transport line, it is possible to greatly reduce the components such as the control unit and the drive electromagnet, thereby realizing a reduction in cost. It also realizes power saving.
[0070]
Moreover, in the conveyance system of this embodiment, although the linear conveyance line is taken as an example, of course, it is not limited to this example. For example, a branch line in which units are arranged so as to branch in the middle of the transfer line (main line) is provided, and a transfer stopper portion that can be moved up and down under the control of the control portion is provided at the branch portion. An arm that moves upward from the branch line is provided. The article to be conveyed is stopped by raising the conveyance stopper. By moving the article onto the branch line side unit by the arm and then driving the branch line unit, a conveyance system having a branch line can be constructed.
[0071]
Furthermore, by arranging the units so that the unit is curved, and arranging the units in the curved part so as to hold the bank so that the article does not jump out, not only the straight line but also the curved conveyance line It can also be constructed.
[0072]
【The invention's effect】
As described in detail above, according to the present invention, a repulsive magnetic levitation unit having a rotating shaft that is levitated by a repulsive magnetic force and is rotatably supported and vibrates in the levitating direction by an electromagnetic field, and a plurality of these units are arranged. In addition, it is possible to provide a repulsive magnetic levitation unit for conveying an article by the rotating shaft and a conveyance system using the unit.
[Brief description of the drawings]
FIG. 1 is a diagram showing an external configuration of a repulsive floating unit according to the present invention.
FIG. 2 is a diagram showing a split element and magnetic flux density distribution of a permanent magnet portion (stator magnet and rotor magnet).
FIG. 3 is a diagram showing a split element and magnetic flux density distribution of an electromagnet part (drive coil and magnetic ring).
FIG. 4 is a diagram showing a repulsive force (repulsive force analysis result) with respect to a position in a permanent magnet portion.
FIG. 5 is a diagram showing the relationship of the attractive force with respect to the gap (FEM analysis result).
FIG. 6 is a diagram showing the results obtained by substituting the numerical values shown in Table 3 into equation (3).
FIG. 7 is a diagram showing a configuration for testing the repulsive levitation unit of the present invention.
FIG. 8 is a diagram showing a change in gap width with respect to time and a vibration component with respect to an excitation frequency.
FIG. 9 is a diagram showing a change in gap width with respect to time and a vibration component with respect to an excitation frequency.
FIG. 10 is a diagram showing a relationship between an average value of a gap and an excitation current.
FIG. 11 is a diagram showing a conceptual configuration of a transport system configured using the repulsive floating unit of the present invention as the first embodiment.
FIG. 12 is a diagram showing an external configuration of a repulsive levitation passive unit used in a transport system according to a second embodiment.
FIG. 13 is a diagram illustrating a conceptual configuration of a transport system according to a second embodiment.
FIG. 14 is a diagram illustrating a conceptual configuration of a transport system according to a third embodiment.
FIG. 15 is a diagram illustrating a conceptual configuration of a transport system according to a fourth embodiment.
[Explanation of symbols]
1 ... Repulsive magnetic levitation unit (unit)
2 ... Base part
3a, 3b ... stopper
4 ... Rotation axis (center axis)
5a, 5b ... Stator magnet stand
6a, 6b ... Coil for driving
7 ... Stator for driving
8 ... Coil drive unit
9a, 9b ... stator magnet
10a, 10b ... rotor magnet
11 ... Magnetic ring

Claims (8)

A base provided with an electromagnet;
A rotating shaft provided with annular first magnets on both side surfaces of the shaft;
A second magnet that is fixed to the base, and has a gap with the entire outer periphery of the first magnet and causes the rotating shaft to float and be penetrated by repulsion;
An annular magnetic body provided on a side surface of the rotating shaft facing the electromagnet;
Comprising
When an alternating current is supplied to the electromagnet, an attractive force corresponding to a frequency is generated between the magnetic body and the alternating current, and the rotating shaft is vibrated to move the mounted article. Repulsive magnetic levitation unit. In the above repulsive magnetic levitation unit,
3. The repulsive magnetic levitation unit according to claim 2, further comprising a stopper portion that is provided so as to be able to contact both end surfaces of the rotation shaft and prevents the rotation shaft from being attached to and detached from the second magnet. 3. The repulsive magnetic levitation unit according to claim 2, wherein both end surfaces of the rotating shaft have a hemispherical shape and become point contact when abutting against the stopper portion. 4. 2. The repulsive magnetic levitation unit according to claim 1, wherein the alternating current supplied to the electromagnet supplies alternating current so that a force is generated at the natural frequency of the rotating shaft. Rotating shafts that are levitated by magnets that repel each other are arranged at a predetermined interval, and the rotation is performed so that vibrations in the flying direction are applied to the respective rotating shafts and the article is pushed out by the vibrations of the rotating shafts. A transport system characterized by moving along an arrangement direction of shafts. A base portion provided with an electromagnet, a rotating shaft provided with annular first magnets on the side surfaces on both ends of the shaft, and fixed to the base portion, repelling the gaps with all side surfaces of the first magnet. A plurality of repulsive magnets, which are composed of a second magnet that is inserted in a floating state with a rotating shaft, and an annular magnetic body provided on a side surface of the rotating shaft facing the electromagnet, and arranged as a conveyance path A levitation unit,
A drive unit that supplies an alternating current to the electromagnet of the repulsive magnetic levitation unit so that a force is generated at the natural frequency of the rotating shaft, and applies a vibration in the flying direction to the rotating shaft;
Comprising
A transport system, wherein when an article is placed on the rotating shaft that vibrates, the article is moved and transported in one direction along the transport path. A first base provided with an electromagnet, a first rotating shaft provided with a ring-shaped first magnet on the side surfaces on both ends of the shaft, and fixed to the first base; A second magnet that is placed in a state where the first rotating shaft is levitated by repulsion with a gap from the side surface, and an annular ring provided on the side surface of the first rotating shaft that faces the first electromagnet A repulsive magnetic levitation unit composed of a magnetic material;
A drive unit that supplies an alternating current to the electromagnet of the repulsive magnetic levitation unit so as to generate a force at the natural frequency of the first rotating shaft, and applies a vibration in the flying direction to the first rotating shaft;
A second rotating shaft provided with annular first magnets on the side surfaces on both ends of the shaft, and fixed to the second base, the second magnet is repelled by leaving a gap with the entire outer periphery of the first magnet. A repulsive magnetic levitation passive unit composed of a second magnet that is inserted with the rotating shaft in a levitating state;
Comprising
One repulsive magnetic levitation unit and a plurality of repulsive magnetic levitation passive units are alternately arranged to form a conveyance path,
The article is moved by the first rotating shaft vibrated by the electromagnet in the repulsive magnetic levitation unit, and the movement is held by the second rotating shaft of the repulsive magnetic levitation passive unit. A transport system for transporting the article along the transport path. A base portion provided with an electromagnet, a rotating shaft provided with annular first magnets on the side surfaces on both ends of the shaft, and fixed to the base portion, repelling the gap with the entire outer periphery of the first magnet. A plurality of repulsive magnets, which are composed of a second magnet that is inserted in a floating state with a rotating shaft, and an annular magnetic body provided on a side surface of the rotating shaft facing the electromagnet, and arranged as a conveyance path A levitation unit,
A plurality of sensors provided above the plurality of rotating shafts of the repulsive magnetic levitation unit on the carry-in side of the transport path, and detecting the presence of an article on the rotating shaft;
A drive unit that supplies an alternating current to the electromagnet of the repulsive magnetic levitation unit so that a force is generated at the natural frequency of the rotating shaft, and applies a vibration in the flying direction to the rotating shaft;
A control unit that controls the drive unit to vibrate by selecting the rotating shaft to be vibrated based on detection signals of the plurality of sensors;
Comprising
When the article is placed on the rotating shaft that vibrates, the size of the article is detected, and the article is moved along the conveyance path by the vibration of the rotating shaft selected by the control unit. A transport system characterized by being transported.

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