JPH05231809A - Electromotive force type eddy current displacement gauge - Google Patents
Electromotive force type eddy current displacement gaugeInfo
- Publication number
- JPH05231809A JPH05231809A JP3670292A JP3670292A JPH05231809A JP H05231809 A JPH05231809 A JP H05231809A JP 3670292 A JP3670292 A JP 3670292A JP 3670292 A JP3670292 A JP 3670292A JP H05231809 A JPH05231809 A JP H05231809A
- Authority
- JP
- Japan
- Prior art keywords
- coil
- eddy current
- metallic object
- lift
- electromotive force
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、電磁誘導作用を利用し
て金属性物体との距離を検出する起電力形渦電流変位計
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromotive force type eddy current displacement meter which detects a distance from a metallic object by utilizing an electromagnetic induction effect.
【０００２】[0002]
【従来の技術】高周波電流を流した励磁コイルによって
磁界を形成し、この磁界内に或る金属性物体が接近した
とき磁界によってその金属性物体に渦電流を発生させ、
この渦電流に基いて前記励起コイルのインピーダンスを
変化させるようにしたインピーダンス変化形渦電流変位
計が知られている。このような変位計は、検出対象物体
との変位すなわち距離（リフトオフ）はもちろんのこ
と、或る検出対象物体の近接の有無を検出する近接スイ
ッチとしても用いられている。2. Description of the Related Art A magnetic field is formed by an exciting coil in which a high frequency current is applied, and when a metallic object approaches the magnetic field, the magnetic field causes an eddy current in the metallic object,
An impedance change type eddy current displacement meter is known in which the impedance of the excitation coil is changed based on this eddy current. Such a displacement meter is used not only as a displacement with respect to the detection target object, that is, a distance (lift-off), but also as a proximity switch for detecting the presence or absence of proximity of a certain detection target object.
【０００３】図６はこのようなインピーダンス変化形渦
電流変位計の概略構成を示すもので、２１は高周波発振
器，２２は電力増幅器（検出器を含む），２３は電力増
幅された高周波電流を流す励磁コイルである。２４は検
出対象物体としての金属性物体で励磁コイル２３と対向
して配置される。FIG. 6 shows a schematic structure of such an impedance change type eddy current displacement meter. Reference numeral 21 is a high frequency oscillator, 22 is a power amplifier (including a detector), and 23 is a power amplified high frequency current. It is an exciting coil. Reference numeral 24 denotes a metallic object as an object to be detected, which is arranged so as to face the exciting coil 23.
【０００４】図７はこのような変位計の動作原理を説明
するものである。高周波電流によって励磁コイル２３は
磁界Ｈを形成し、この磁界Ｈによって金属性物体２４に
同心円状の渦電流ｉ′が流れる。そしてこの渦電流ｉに
よって励磁コイル２３による磁界Ｈと反対方向の磁界
Ｈ′が生ずる。これら各磁界Ｈ，Ｈ′が重畳して励磁コ
イル２３のインピーダンスを変化させる。φ，φ′は各
磁界Ｈ，Ｈ′によって生じる磁束を示している。FIG. 7 illustrates the operating principle of such a displacement meter. The exciting coil 23 forms a magnetic field H by the high frequency current, and the magnetic field H causes a concentric eddy current i ′ to flow through the metallic object 24. The eddy current i produces a magnetic field H'in the direction opposite to the magnetic field H generated by the exciting coil 23. These magnetic fields H and H'are superposed to change the impedance of the exciting coil 23. φ and φ'indicate magnetic fluxes generated by the magnetic fields H and H '.
【０００５】従ってこの場合のコイル２３のインピーダ
ンスＺ′は、金属性物体２４が存在していない場合の値
Ｚに比べて減少することになる。これは高周波発振器２
１で発生される高周波電圧ｅを一定としたとき、高周波
電流ｉが変化することになる。さらに金属性物体２４に
発生する渦電流ｉ′の大きさは、励磁コイル２３と金属
性物体２４との間の距離Ｌすなわちリフトオフに逆比例
する。これによって励磁コイル２３のインピーダンスＺ
または電流を測定することにより、リフトオフを検出す
ることができるようになる。Therefore, the impedance Z'of the coil 23 in this case becomes smaller than the value Z when the metallic object 24 is not present. This is a high frequency oscillator 2
When the high frequency voltage e generated at 1 is constant, the high frequency current i changes. Further, the magnitude of the eddy current i ′ generated in the metallic object 24 is inversely proportional to the distance L between the exciting coil 23 and the metallic object 24, that is, the lift-off. As a result, the impedance Z of the exciting coil 23
Alternatively, the lift-off can be detected by measuring the current.
【０００６】ここでこのようなインピーダンス変化形渦
電流変位計を用いて検出対象物体である金属性物体２４
の近接状態を検出するには、予め検出距離に対応させて
複数種の励磁コイルを用意しておくことが行われてい
る。例えば、５ｍｍ用，１０ｍｍ用，１５ｍｍ用といっ
た複数種のものが用意される。そして目的に応じたもの
が選ばれる。Here, a metallic object 24 which is an object to be detected is measured by using such an impedance change type eddy current displacement meter.
In order to detect the close state, the plural kinds of exciting coils are prepared in advance corresponding to the detection distance. For example, a plurality of types such as 5 mm, 10 mm, and 15 mm are prepared. Then, the one that suits the purpose is selected.
【０００７】[0007]
【発明が解決しようとする課題】ところでこのようなイ
ンピーダンス変化形渦電流変位計では、予め検出距離に
応じた複数種の励磁コイルを用意しておいて、必要な都
度目的のものを選んで交換しなければならないので、検
出効率が悪くなると共にコストアップになるという問題
がある。By the way, in such an impedance change type eddy current displacement meter, a plurality of kinds of exciting coils are prepared in advance according to the detection distance, and the desired one is selected and replaced whenever necessary. Therefore, there is a problem that the detection efficiency is deteriorated and the cost is increased.
【０００８】本発明は以上のような問題に対処してなさ
れたもので、単一の励磁コイルを用い検出コイルを交換
するだけで広範囲のリフトオフの検出を可能にした起電
力形渦電流変位計を提供することを目的とするものであ
る。The present invention has been made in consideration of the above problems, and is an electromotive force type eddy current displacement meter capable of detecting a wide range of lift-off by using a single exciting coil and exchanging the detecting coil. It is intended to provide.
【０００９】[0009]
【課題を解決するための手段】上記目的を達成するため
に本発明は、高周波電流を流した励磁コイルに近接して
検出コイルを配置し、前記励磁コイルによって形成され
る磁界内に金属性物体が接近してこの金属性物体に渦電
流が発生したとき、この渦電流に基いて前記検出コイル
に金属性物体との距離に応じた起電力を誘起させること
を特徴とするものである。In order to achieve the above-mentioned object, the present invention has a detection coil arranged in the vicinity of an exciting coil in which a high frequency current is passed, and a metallic object is placed in a magnetic field formed by the exciting coil. When an eddy current is generated in the metallic object due to an approach, the electromotive force corresponding to the distance from the metallic object is induced in the detection coil based on the eddy current.
【００１０】[0010]
【作用】請求項１記載の本発明の構成によれば、検出コ
イルを配置した状態で励磁コイルによって形成された磁
界内に接近させた金属性物体に渦電流を発生させ、この
渦電流に基いて検出コイルに金属性物体とのリフトオフ
に応じた起電力を誘起させる。According to the structure of the present invention as set forth in claim 1, an eddy current is generated in a metallic object brought close to the magnetic field formed by the exciting coil with the detection coil arranged, and the eddy current is generated based on this eddy current. Then, the detection coil is caused to induce an electromotive force corresponding to lift-off with the metallic object.
【００１１】請求項２記載の本発明の構成によれば、検
出コイルを励磁コイルと金属性物体との間に配置した状
態で請求項１と同様な作用を行わせることができる。According to the configuration of the present invention as set forth in claim 2, the same operation as in claim 1 can be performed in a state where the detection coil is arranged between the exciting coil and the metallic object.
【００１２】請求項３記載の本発明の構成によれば、金
属性物体とのリフトオフの測定範囲に応じて検出コイル
の直径を設定することにより、効率の良い検出を行うこ
とができる。According to the third aspect of the present invention, by setting the diameter of the detection coil in accordance with the measurement range of lift-off with the metallic object, efficient detection can be performed.
【００１３】[0013]
【実施例】以下図面を参照して本発明の実施例を説明す
る。Embodiments of the present invention will be described below with reference to the drawings.
【００１４】図１は本発明の起電力形渦電流変位計の実
施例を示す概略構成図で、１は高周波発振器，２は電力
増幅器，３は励磁コイル，４は金属性物体で、以上の構
成は従来と同一である。５は検出コイルで励磁コイル３
と金属性物体４との間に配置され、後述のように金属性
物体４に流れる渦電流ｉ′に基いてこの金属性物体４の
リフトオフＬに応じた起電力を誘起するためのものであ
る。６は誘起起電力を増幅する増幅器，７は誘起起電力
を測定する電圧計である。FIG. 1 is a schematic constitutional view showing an embodiment of an electromotive force type eddy current displacement meter of the present invention. 1 is a high frequency oscillator, 2 is a power amplifier, 3 is an exciting coil, and 4 is a metallic object. The configuration is the same as the conventional one. Reference numeral 5 is a detection coil and excitation coil 3
It is arranged between the metallic object 4 and the metallic object 4 and induces an electromotive force according to the lift-off L of the metallic object 4 based on the eddy current i ′ flowing in the metallic object 4 as described later. .. 6 is an amplifier for amplifying the induced electromotive force, and 7 is a voltmeter for measuring the induced electromotive force.
【００１５】このような構成において、図７と同様な原
理によって検出コイル５には、励磁コイル３による磁界
と金属性物体４に流れる渦電流によって生ずる磁界が重
畳することによって、金属性物体４とのリフトオフに応
じた起電力が誘起される。すなわち、励磁コイル３によ
る磁束φが金属性物体４と鎖交すると、金属性物体４に
は電磁誘導作用により起電力が発生して渦電流ｉ′が流
れる。そしてこの渦電流ｉによって磁束φと反対方向の
磁束φ′が発生され、この磁束φ′とφが重畳して検出
コイル５と鎖交する。従って、渦電流ｉ′はリフトオフ
に応じて変化するので、金属性物体４とのリフトオフに
応じた起電力が検出コイル５に誘起されることになる。In such a structure, the magnetic field generated by the exciting coil 3 and the magnetic field generated by the eddy current flowing in the metallic object 4 are superposed on the detection coil 5 according to the same principle as in FIG. An electromotive force corresponding to the lift-off of is induced. That is, when the magnetic flux φ generated by the exciting coil 3 interlinks with the metallic object 4, an electromotive force is generated in the metallic object 4 by an electromagnetic induction action, and an eddy current i ′ flows. The eddy current i generates a magnetic flux φ ′ in the opposite direction to the magnetic flux φ, and the magnetic flux φ ′ and φ are superposed and interlink with the detection coil 5. Therefore, the eddy current i ′ changes according to the lift-off, so that an electromotive force corresponding to the lift-off with the metallic object 4 is induced in the detection coil 5.
【００１６】励磁コイル３は一例として平均半径７ｍ
ｍ，巻数３５０ターンのブルックス型コイルを用いた。
また、検出コイル５は巻数Ｎ（１乃至５ターン），直径
Ｄの同心円形コイルを用いて励磁コイル３の下方に配置
した。さらに増幅器６としては利得４０ｄＢのものを用
いて検出コイル５に接続した。The exciting coil 3 has an average radius of 7 m as an example.
A Brooks-type coil with m and 350 turns was used.
The detection coil 5 is a concentric circular coil having a number of turns N (1 to 5 turns) and a diameter D, and is arranged below the exciting coil 3. Further, the amplifier 6 having a gain of 40 dB was used and connected to the detection coil 5.
【００１７】次に本実施例の作用について各種特性を参
照して以下説明する。The operation of this embodiment will be described below with reference to various characteristics.
【００１８】図２は金属性物体４として鉄板を用いたと
きの、リフトオフＬの変化に対して検出コイル５の誘起
起電力が一定となる励磁周波数ｆｏ（縦軸）と検出コイ
ル５の直径Ｄ（横軸）との関係を示したものである。横
軸の直径Ｄが増加するにつれて、縦軸の励磁周波数ｆｏ
は低下する。FIG. 2 shows the excitation frequency fo (vertical axis) and the diameter D of the detection coil 5 at which the induced electromotive force of the detection coil 5 becomes constant against changes in the lift-off L when an iron plate is used as the metallic object 4. The relationship with (horizontal axis) is shown. As the diameter D on the horizontal axis increases, the excitation frequency fo on the vertical axis
Will fall.
【００１９】或る直径Ｄを設定したとき、これに対応し
た励磁周波数ｆｏより高い励磁周波数すなわちｂ領域の
励磁周波数を選んだ場合、検出コイル５の出力電圧Ｖ
（縦軸）とリフトオフＬ（横軸）との関係を示すと、図
３の特性Ｂのようになる。一例として検出コイル５は、
Ｄ＝８２ｍｍ，Ｎ＝１ターンに設定して、ｆ＝４７ＫＨ
ｚを選んだ場合で示している。When a certain diameter D is set and an excitation frequency higher than the corresponding excitation frequency fo, that is, an excitation frequency in the region b is selected, the output voltage V of the detection coil 5
The relationship between the (vertical axis) and the lift-off L (horizontal axis) is shown by the characteristic B in FIG. As an example, the detection coil 5 is
Setting D = 82mm, N = 1 turn, f = 47KH
This is shown when z is selected.
【００２０】一方、Ｄに対応した励磁周波数ｆｏより低
い励磁周波数すなわちａ領域の励磁周波数を選んだ場
合、同様に出力電圧ＶとリフトオフＬとの関係を示す
と、図３の特性Ａのようになる。一例として検出コイル
５は、前記同様にＤ＝８２ｍｍ，Ｎ＝１ターンに設定し
て、ｆ＝４７０Ｈｚに選んだ場合で示している。ここ
で、変化の割合は同一直径Ｄのとき、図２における励磁
周波数ｆｏより離れる程この傾向は顕著になる。On the other hand, when an excitation frequency lower than the excitation frequency fo corresponding to D, that is, the excitation frequency in the region a is selected, the relationship between the output voltage V and the lift-off L is similarly shown as the characteristic A in FIG. Become. As an example, the detection coil 5 is shown in a case where D = 82 mm and N = 1 turn are set and f = 470 Hz is selected as in the above. Here, when the rate of change is the same diameter D, the tendency becomes more prominent as the distance from the excitation frequency fo in FIG. 2 increases.
【００２１】図３の特性Ａ，特性Ｂを比較して明らかな
ように、特性Ｂのように図２のＤに対応した励磁周波数
ｆｏより高いｂ領域の励磁周波数を選んだ場合、出力電
圧ＶはリフトオフＬの増加につれて増加するように変化
する。従ってこの特性Ｂのように選ぶことにより、リフ
トオフの検出を行う場合検出がし易くなる。従って以下
特性Ｂを利用した例で説明する。As is clear from comparison between the characteristics A and B in FIG. 3, when the excitation frequency in the region b higher than the excitation frequency fo corresponding to D in FIG. 2 is selected as in the characteristic B, the output voltage V Changes as the lift-off L increases. Therefore, if the characteristic B is selected, the lift-off can be detected easily. Therefore, an example using the characteristic B will be described below.
【００２２】図４は検出コイル５の直径Ｄをパラメータ
としたときの、出力電圧Ｖ（縦軸）とリフトオフＬ（横
軸）との関係を示すもので、特性ＡはＤ＝６０ｍｍに設
定した場合、特性ＢはＤ＝１５０ｍｍに設定した場合の
例を示している。一例としてＮ＝１ターン，ｆ＝８０Ｋ
Ｈｚ，励磁電流ｉ＝２ｍＡに選んだ場合で示している。FIG. 4 shows the relationship between the output voltage V (vertical axis) and the lift-off L (horizontal axis) when the diameter D of the detection coil 5 is used as a parameter, and the characteristic A is set to D = 60 mm. In this case, the characteristic B shows an example in which D = 150 mm is set. As an example, N = 1 turn, f = 80K
It is shown in the case of selecting Hz and exciting current i = 2 mA.
【００２３】図４の特性Ａ，特性Ｂから明らかなよう
に、リフトオフＬが小さい範囲では、直径の小さな特性
Ａの方が出力電圧ＶがリフトオフＬの変化に比例し、リ
フトオフＬが広い範囲では、直径の大きな特性Ｂの方が
出力電圧ＶがリフトオフＬの変化に比例して得られるこ
とが理解される。従って検出対象である金属性物体との
リフトオフに応じて検出コイル５の直径Ｄを設定するこ
とにより、効率の良い検出を行うことができる。As is clear from the characteristics A and B of FIG. 4, in the range where the lift-off L is small, the characteristic A having a smaller diameter is more proportional to the change of the lift-off L in the output voltage V, and in the range where the lift-off L is wider. It is understood that the characteristic B having a larger diameter provides the output voltage V in proportion to the change in the lift-off L. Therefore, efficient detection can be performed by setting the diameter D of the detection coil 5 according to the lift-off with the metallic object that is the detection target.
【００２４】図５は金属性物体４として鉄（○印），ア
ルミニウム（□印），しんちゅう（△印）を各々用いた
場合の、出力電圧Ｖ（縦軸）とリフトオフＬ（横軸）と
の関係を示すものである。一例として、ｆ＝３００ＫＨ
ｚ，ｉ＝２０ｍＡ，Ｄ＝１３０ｍｍ，Ｎ＝５ターン，増
幅度＝１に選んだ場合を示している。各特性ともリフト
オフＬが０．５乃至２．５ｃｍの範囲で直線性良く検出
できることを示している。FIG. 5 shows the output voltage V (vertical axis) and the lift-off L (horizontal axis) when iron (○), aluminum (□), and brass (Δ) are used as the metallic object 4. It shows the relationship with. As an example, f = 300KH
It shows a case where z, i = 20 mA, D = 130 mm, N = 5 turns, and amplification degree = 1. Each of the characteristics shows that the lift-off L can be detected with good linearity in the range of 0.5 to 2.5 cm.
【００２５】以上述べたように本実施例によれば、励磁
コイル３と金属性物体４との間に検出コイル５を配置
し、金属性物体４に発生した渦電流に基いて、金属性物
体とのリフトオフに応じた起電力を検出コイル５に誘起
するようにしたので、単一の励磁コイル３に直径Ｄの異
なる検出コイル５を用いることで広範囲のリフトオフを
検出することができる。この場合検出コイル５は検出対
象に応じて直径Ｄの異なるものを用意しておいて、検出
範囲に応じて使い分けるようにする。この検出コイル５
の配置は、簡単な作業によって行うことができるので、
何ら作業が煩わしくなることはない。よって従来のよう
に測定範囲によって励磁コイル３を交換する必要はな
く、１個の励磁コイルを用意するだけでよいので、リフ
トオフの検出効率を改善することができる。As described above, according to this embodiment, the detection coil 5 is arranged between the exciting coil 3 and the metallic object 4, and the metallic object is detected based on the eddy current generated in the metallic object 4. Since the electromotive force corresponding to the lift-offs of 1 and 2 is induced in the detection coil 5, it is possible to detect a wide range of lift-offs by using the detection coils 5 having different diameters D in the single exciting coil 3. In this case, the detection coil 5 having different diameters D is prepared according to the object to be detected, and is selectively used according to the detection range. This detection coil 5
Can be placed by a simple operation, so
No work is annoying. Therefore, unlike the conventional case, it is not necessary to replace the exciting coil 3 depending on the measurement range, and only one exciting coil needs to be prepared, so that lift-off detection efficiency can be improved.
【００２６】また、出力電圧Ｖの大きさは検出コイル５
の巻数Ｎに比例して取出せるので、任意の巻数を選ぶこ
とができる。Further, the magnitude of the output voltage V is determined by the detection coil 5
Since it can be taken out in proportion to the number N of turns of N, any number of turns can be selected.
【００２７】さらに、金属性物体４の表面荒さにより、
表皮効果を考慮した励磁コイル３の励磁周波数を設定す
ることにより、リフトオフの検出範囲に応じて自由に検
出コイル５の直径Ｄが設計できるようになる。Further, due to the surface roughness of the metallic object 4,
By setting the excitation frequency of the excitation coil 3 in consideration of the skin effect, the diameter D of the detection coil 5 can be freely designed according to the lift-off detection range.
【００２８】[0028]
【発明の効果】以上述べたように本発明によれば、励磁
コイルと検出コイルを分離して、単一の励磁コイルに対
して直径の異なる数種の検出コイルを用意するようにし
たので、微小変位から数ｃｍに及ぶ広範囲のリフトオフ
の検出が、効率良くしかもコストアップを伴うことなく
行える。As described above, according to the present invention, the exciting coil and the detecting coil are separated, and several detecting coils having different diameters are prepared for a single exciting coil. It is possible to detect lift-off in a wide range from a minute displacement to several cm efficiently and without increasing cost.
【図１】本発明の起電力形渦電流変位計の実施例を示す
概略構成図である。FIG. 1 is a schematic configuration diagram showing an embodiment of an electromotive force type eddy current displacement meter of the present invention.
【図２】本実施例における出力電圧がリフトオフに無関
係となる励磁周波数と検出コイルの直径との関係を示す
特性図である。FIG. 2 is a characteristic diagram showing the relationship between the excitation frequency and the diameter of the detection coil, which makes the output voltage irrelevant to lift-off in this embodiment.
【図３】本実施例において得られた励磁周波数をパラメ
ータとしたリフトオフと出力電圧との関係を示す特性図
である。FIG. 3 is a characteristic diagram showing the relationship between lift-off and output voltage with the excitation frequency obtained as a parameter in the present embodiment.
【図４】本実施例において得られたリフトオフと出力電
圧との関係を示す特性図である。FIG. 4 is a characteristic diagram showing the relationship between lift-off and output voltage obtained in this example.
【図５】本実施例において得られたリフトオフと出力電
圧との関係を示す特性図である。FIG. 5 is a characteristic diagram showing the relationship between lift-off and output voltage obtained in this embodiment.
【図６】従来のインピーダンス変化形渦電流変位計を示
す概略構成図である。FIG. 6 is a schematic configuration diagram showing a conventional impedance change type eddy current displacement meter.
【図７】インピーダンス変化形渦電流変位計の動作原理
を示す説明図である。FIG. 7 is an explanatory diagram showing the operation principle of the impedance change type eddy current displacement meter.
３ 励磁コイル ４ 金属性物体（検出対象） ５ 検出コイル 3 Excitation coil 4 Metal object (Detection target) 5 Detection coil
Claims (3)
て検出コイルを配置し、前記励磁コイルによって形成さ
れる磁界内に金属性物体が接近してこの金属性物体に渦
電流が発生したとき、この渦電流に基いて前記検出コイ
ルに金属性物体との距離に応じた起電力を誘起させるこ
とを特徴とする起電力形渦電流変位計。1. A detection coil is arranged in the vicinity of an exciting coil in which a high-frequency current is passed, and a metallic object approaches in a magnetic field formed by the exciting coil and an eddy current is generated in the metallic object. An electromotive force type eddy current displacement meter characterized in that an electromotive force is induced in the detection coil based on the eddy current according to the distance from the metallic object.
体との間の位置に配置される請求項１記載の起電力形渦
電流変位計。2. The electromotive force type eddy current displacement meter according to claim 1, wherein the detection coil is arranged at a position between the exciting coil and the metallic object.
属性物体との距離の測定範囲を可変させる請求項１記載
の起電力形渦電流変位計。3. The electromotive force type eddy current displacement meter according to claim 1, wherein the measuring range of the distance to the metallic object is changed by setting the diameter of the detection coil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3670292A JPH05231809A (en) | 1992-02-24 | 1992-02-24 | Electromotive force type eddy current displacement gauge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3670292A JPH05231809A (en) | 1992-02-24 | 1992-02-24 | Electromotive force type eddy current displacement gauge |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05231809A true JPH05231809A (en) | 1993-09-07 |
Family
ID=12477104
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3670292A Pending JPH05231809A (en) | 1992-02-24 | 1992-02-24 | Electromotive force type eddy current displacement gauge |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05231809A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0361698A1 (en) * | 1988-09-05 | 1990-04-04 | Mitsubishi Petrochemical Company Limited | Carbon-containing magnetic metal powder |
| JP2007298300A (en) * | 2006-04-27 | 2007-11-15 | Chubu Regional Bureau Ministry Of Land Infrastructure & Transport | Metal detector and metal detection method |
| JPWO2007148429A1 (en) * | 2006-06-19 | 2009-11-12 | 株式会社ニューコム | Object detection device for detecting an object using electromagnetic induction |
| JP2011058830A (en) * | 2009-09-07 | 2011-03-24 | Tosho Inc | Detector of metal foreign matter |
| JP2011064590A (en) * | 2009-09-17 | 2011-03-31 | Ebara Corp | Eddy current sensor, polishing apparatus, plating apparatus, polishing method, plating method |
-
1992
- 1992-02-24 JP JP3670292A patent/JPH05231809A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0361698A1 (en) * | 1988-09-05 | 1990-04-04 | Mitsubishi Petrochemical Company Limited | Carbon-containing magnetic metal powder |
| JP2007298300A (en) * | 2006-04-27 | 2007-11-15 | Chubu Regional Bureau Ministry Of Land Infrastructure & Transport | Metal detector and metal detection method |
| JPWO2007148429A1 (en) * | 2006-06-19 | 2009-11-12 | 株式会社ニューコム | Object detection device for detecting an object using electromagnetic induction |
| JP5028552B2 (en) * | 2006-06-19 | 2012-09-19 | 株式会社Ｎｃ３ | Object detection device for detecting an object using electromagnetic induction |
| JP2011058830A (en) * | 2009-09-07 | 2011-03-24 | Tosho Inc | Detector of metal foreign matter |
| JP2011064590A (en) * | 2009-09-17 | 2011-03-31 | Ebara Corp | Eddy current sensor, polishing apparatus, plating apparatus, polishing method, plating method |
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