JPH0523361B2 - - Google Patents
Info
- Publication number
- JPH0523361B2 JPH0523361B2 JP27316184A JP27316184A JPH0523361B2 JP H0523361 B2 JPH0523361 B2 JP H0523361B2 JP 27316184 A JP27316184 A JP 27316184A JP 27316184 A JP27316184 A JP 27316184A JP H0523361 B2 JPH0523361 B2 JP H0523361B2
- Authority
- JP
- Japan
- Prior art keywords
- secondary coil
- coil
- eddy current
- metal plate
- distance
- 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.)
- Expired - Lifetime
Links
- 238000005259 measurement Methods 0.000 claims description 24
- 230000006698 induction Effects 0.000 claims description 14
- 239000002184 metal Substances 0.000 description 22
- 238000006073 displacement reaction Methods 0.000 description 9
- 230000035945 sensitivity Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 6
- 238000001514 detection method Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000013535 sea water Substances 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
Landscapes
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は差動相互誘導型渦流計測用センサに関
し、詳しくは２個の２次コイルを有する差動相互
誘導型渦流計測用センサに関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a differential mutual induction type eddy current measurement sensor, and more particularly to a differential mutual induction type eddy current measurement sensor having two secondary coils.
渦流計測は、例えば渦流計測用のセンサである
コイルから金属板までの距離等の測定に広く実用
化されている。かかる渦流計測は原理的にはコイ
ルと金属板を対向配置し、該コイルと金属板との
距離に対応する大きさとなるコイルの自己インダ
クタンスを測定することによつて行なうものであ
る。また、２次コイルを挾んで１次コイルと金属
板とを対向配置し、１次コイルと２次コイルの相
互インダクタンスを測定することによつて前記自
己インダクタンスの測定よりも高い精度の測定結
果が得られる。さらに、高精度の渦流計測とし
て、１次コイルを挾んで第１および第２の２次コ
イルを対向配置させる方法がある。
Eddy current measurement is widely put into practical use, for example, to measure the distance from a coil, which is a sensor for eddy current measurement, to a metal plate. In principle, such eddy current measurement is performed by arranging a coil and a metal plate facing each other and measuring the self-inductance of the coil, which has a size corresponding to the distance between the coil and the metal plate. Furthermore, by arranging the primary coil and a metal plate facing each other with the secondary coil in between, and measuring the mutual inductance between the primary and secondary coils, a measurement result with higher accuracy than the self-inductance measurement can be obtained. can get. Furthermore, as a highly accurate eddy current measurement method, there is a method in which first and second secondary coils are disposed opposite to each other with a primary coil sandwiched therebetween.
第２図はかかる２個の２次コイルを備えた従来
の差動相互誘導型渦流計測用センサの概略図であ
る。巻線数Ｎ１の１次コイルＰを挾んで対向配置
された第１の２次コイルＳ１および第２の２次コ
イルＳ２は、それぞれ配置方向の長さｌ１が等し
く、また１次コイルＰとの間隔が等しく、さらに
巻線数がＮ２になつている。したがつて、これら
のコイルＰ，Ｓ１およびＳ２の近くに金属板MP
がないときは、１次コイルＰと第１の２次コイル
SP１との相互インダクタンスM1および１次コイ
ルＰと第２の２次コイルＳ２との相互インダクタ
ンスM2は等しく、
M1＝M2 (1)
が成立する。第１の２次コイルＳ１の近くに金属
板MPを置くと、第１の２次コイルＳ１は１次コ
イルよりも金属板MPに近いので、相互インダク
タンスM1、M2は、
M1＜M2 (2)
となる。このため、相互インダクタンスM1、M2
の変位感度△M1、△M2は、変位感度△M1の方
が大きく、
△M1＞△M2 (3)
となる。また、第３図に示すように、第１および
第２の２次コイルＳ１およびＳ２を差動接続する
と、変位感度は
△（M1−M2）＝△M1−△M2 (4)
となる。 FIG. 2 is a schematic diagram of a conventional differential mutual induction type eddy current measurement sensor equipped with such two secondary coils. The first secondary coil S1 and the second secondary coil S2, which are arranged opposite to each other with the primary coil P having the number of windings N1 in between, have the same length l1 in the arrangement direction, and have the same length l1 as the primary coil P. The spacing is equal, and the number of windings is N2. Therefore, a metal plate MP is placed near these coils P, S1 and S2.
If not, the primary coil P and the first secondary coil
Mutual inductance M1 with SP1 and mutual inductance M2 between primary coil P and second secondary coil S2 are equal, and M1=M2 (1) holds true. When a metal plate MP is placed near the first secondary coil S1, the first secondary coil S1 is closer to the metal plate MP than the primary coil, so the mutual inductance M1 and M2 is M1<M2 (2) becomes. For this reason, the mutual inductance M1, M2
The displacement sensitivity △M1 and △M2 are larger, and △M1>△M2 (3). Further, as shown in FIG. 3, when the first and second secondary coils S1 and S2 are differentially connected, the displacement sensitivity becomes Δ(M1-M2)=ΔM1-ΔM2 (4).
ところで、第１の２次コイルＳ１と金属板MP
との距離h1が大きくなると、変位感度△M1と△
M2との差、すなわち、第(4)式に示した変位感度
の値が小さくなつてしまい、相互インダクタンス
に基づいて測定される第１の２次コイルＳ１と金
属板MPとの距離が大きな誤差を含んでしまうこ
とになり、問題であつた。また、場合によつて
は、距離の測定が不可能になつてしまうという問
題があつた。
By the way, the first secondary coil S1 and the metal plate MP
As the distance h 1 increases, the displacement sensitivities △M1 and △
M2, that is, the displacement sensitivity value shown in equation (4) becomes small, and the distance between the first secondary coil S1 and the metal plate MP measured based on mutual inductance has a large error. This was a problem. Additionally, there is a problem in that distance measurement becomes impossible in some cases.
本発明は上記問題点を解決する目的でなされた
もので、金属板までの距離が離れている場合であ
つても、該金属板までの距離を正確に測定できる
差動相互誘導型渦流計測用センサを提供するもの
である。 The present invention was made for the purpose of solving the above problems, and is a differential mutual induction type eddy current measurement device that can accurately measure the distance to a metal plate even if the distance to the metal plate is far. It provides a sensor.
そこで本発明は、被測定物に対して近い第１の
２次コイルと、被測定物に対して第１の２次コイ
ルより遠い第２の２次コイルを１次コイルを挟ん
で対向配置し、１次コイルと第１の２次コイルと
の間隔を該１次コイルと第２の２次コイルとの間
隔よりも大きくするとともに、第１の２次コイル
の巻線数を第２の２次コイルの巻線数よりも多き
くした差動相互誘導型渦流計測用センサを構成す
る。
Therefore, in the present invention, a first secondary coil that is close to the object to be measured and a second secondary coil that is farther from the object to be measured than the first secondary coil are arranged facing each other with the primary coil in between. , the distance between the primary coil and the first secondary coil is made larger than the distance between the primary coil and the second secondary coil, and the number of turns of the first secondary coil is increased from the second A differential mutual induction type eddy current measurement sensor is constructed in which the number of turns is greater than that of the secondary coil.
上記構成の差動相互誘導型渦流計測用センサ
は、被測定物に対して近い第１の２次コイルと被
測定物に対して遠い第２の２次コイルとを差動接
続し、１次コイルの一方の端子と第１または第２
の２次コイルの一方の端子とを接続して１次コイ
ルに交流電流を供給し、このとき差動接続された
第１および第２の２次コイルに誘起する電或を測
定し、これらの電流、電圧値により相互インダク
タンスを求め、この相互インダクタンスに基づい
て第１の２次コイル側に置かれた金属板までの距
離を算出する。
The differential mutual induction type eddy current measurement sensor having the above configuration differentially connects a first secondary coil close to the object to be measured and a second secondary coil far from the object to be measured, and one terminal of the coil and the first or second
An alternating current is supplied to the primary coil by connecting it to one terminal of the secondary coil, and at this time, the electric current induced in the first and second secondary coils which are differentially connected is measured, and these Mutual inductance is determined from the current and voltage values, and based on this mutual inductance, the distance to the metal plate placed on the first secondary coil side is calculated.
以下、本発明の一実施例を添付図面を参照して
詳細に説明する。
Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.
第１図は本発明に係る差動相互誘導型渦流計測
用センサの概略図である。第１図において、第１
の２次コイルＳ１および第２の２次コイルＳ２
は、該第１の２次コイルＳ１と１次コイルＢとの
間隔が該第２の２次コイルＳ２と１次コイルＰと
の間隔よりも大きくなるように、巻線数N1の１
次コイルＰを挾んで対向配置されている。また、
第１の２次コイルＳ１の巻線数N2が第２の２次
コイルＳ２の巻線数N2′よりも多くなつている。
このため、第１の２次コイルＳ１側に金属板MP
を置くと、１次コイルＰと第１の２次コイルＳ１
との相互インダクタンスM1の変位感度△M1は１
次コイルＰと第２の２次コイルＳ２との相互イン
ダクタンスM2の変位感度△M2よりも大きく、第
１の２次コイルＳ１と金属板MPとの距離h1が大
きい場合であつても、
△M1≫△M2 (5)
となり、第１の２次コイルＳ１と第２の２次コイ
ルＳ２とを差動接続したときの変位感度が変位感
度△M2によつて減弱されることがなくなる。 FIG. 1 is a schematic diagram of a differential mutual induction type eddy current measurement sensor according to the present invention. In Figure 1, the first
secondary coil S1 and second secondary coil S2
is 1 of the number of turns N1 so that the distance between the first secondary coil S1 and the primary coil B is larger than the distance between the second secondary coil S2 and the primary coil P.
They are arranged opposite to each other with the next coil P in between. Also,
The number of turns N2 of the first secondary coil S1 is greater than the number N2' of turns of the second secondary coil S2.
Therefore, the metal plate MP is placed on the first secondary coil S1 side.
, the primary coil P and the first secondary coil S1
The displacement sensitivity △M1 of the mutual inductance M1 is 1
Even if the displacement sensitivity of the mutual inductance M2 between the primary coil P and the second secondary coil S2 is larger than △M2, and the distance h1 between the first secondary coil S1 and the metal plate MP is large, △ M1≫ΔM2 (5) Therefore, the displacement sensitivity when the first secondary coil S1 and the second secondary coil S2 are differentially connected is not weakened by the displacement sensitivity ΔM2.
次に、第１図に示した差動相互誘導型渦流計測
用センサの相互インダクタンスの測定について説
明する。相互インダクタンスを測定するときに
は、第３図に示すようにまず、第１の２次コイル
Ｓ１と第２の２次コイルＳ２とを差動接続する。
すなわち、第１の２次コイルＳ１の一方の端子
１′を第２の２次コイルＳ２の一方の端子２とを
接続する。また、１次コイルＰの一方の端子３を
第１の２次コイルＳ１の一方の端子１に接続す
る。このような接続状態で、１次コイルＰの両端
子１，１′間に所定周波数ｆの交流電流Ｉを流す
と、差動接続された第１および第２の２次コイル
Ｓ１およびＳ２は開放状態にあつて、端子４−
４′間に誘起電圧Ｅが誘起される。このとき、ｆ、
Ｉ、Ｅおよび相互インダクタンス（M2−M1）に
より次式が得られる。 Next, measurement of mutual inductance of the differential mutual induction type eddy current measuring sensor shown in FIG. 1 will be explained. When measuring mutual inductance, first, as shown in FIG. 3, the first secondary coil S1 and the second secondary coil S2 are differentially connected.
That is, one terminal 1' of the first secondary coil S1 is connected to one terminal 2 of the second secondary coil S2. Further, one terminal 3 of the primary coil P is connected to one terminal 1 of the first secondary coil S1. In this connected state, when an alternating current I of a predetermined frequency f is passed between both terminals 1 and 1' of the primary coil P, the differentially connected first and second secondary coils S1 and S2 are opened. condition, terminal 4-
An induced voltage E is induced between 4' and 4'. At this time, f,
The following equation is obtained by I, E and mutual inductance (M2-M1).
Ｅ＝2πf（M2−M1）Ｉ (6)
したがつて、相互インダクタンス（M2−M1）
は、
（M2−M1）＝Ｅ／2πfI (7)
により求められる。 E=2πf(M2−M1)I (6) Therefore, mutual inductance (M2−M1)
is obtained by (M2−M1)=E/2πfI (7).
上記方法により相互インダクタンスを測定する
場合、第(1)式が必ずしも成立する必要はない。第
(1)式が成立しないときは、
M1＜M2 (8)
が成立している。したがつて、相互インダクタン
ス（M2−M1）は金属板MPを第１の２次コイル
Ｓ１から遠ざけると最小となり、金属板MPを第
１の２次コイルＳ１に近づけると最大となるの
で、変化割合△（M2−M1）／（M2−M1）を考
慮すると有利であることがわかる。 When measuring mutual inductance by the above method, equation (1) does not necessarily have to hold true. No.
When equation (1) does not hold, M1<M2 (8) holds. Therefore, the mutual inductance (M2-M1) becomes minimum when the metal plate MP is moved away from the first secondary coil S1, and maximum when the metal plate MP is brought closer to the first secondary coil S1, so the rate of change is It can be seen that it is advantageous to consider Δ(M2-M1)/(M2-M1).
なお、本発明による差動相互誘導型渦流計測用
センサは上記のように差動接続せず、６端子のま
まで測定装置に接続して使用する場合がある。こ
の場合、測定装置内において、第１および第２の
コイルの各誘起電圧が差動接続した場合と同じよ
うに作用するようになつている。 Note that the differential mutual induction type eddy current measurement sensor according to the present invention may be used without differential connection as described above, and connected to a measuring device with six terminals as is. In this case, within the measuring device, the induced voltages of the first and second coils act in the same way as if they were differentially connected.
また、第２図に示した従来の渦流計測用センサ
はセンサであるコイルの温度変化に対する補償効
果を有するが、本発明による差動相互誘導型渦流
計測用センサであつても、該補償効果が失なわれ
ることがない。 Further, although the conventional eddy current measurement sensor shown in FIG. 2 has a compensation effect for temperature changes in the coil that is the sensor, even the differential mutual induction type eddy current measurement sensor according to the present invention does not have this compensation effect. It will never be lost.
また、本実施例では金属板迄の距離測定につい
て説明したが、金属板の誘電率測定、金属板の探
傷（傷の検出）あるいはメタル検出などに適用で
き、特に被測定物迄の距離が大きいときには効果
が大きい。 In addition, although this example describes distance measurement to a metal plate, it can also be applied to dielectric constant measurement of metal plates, flaw detection (flaw detection) of metal plates, metal detection, etc., especially when the distance to the object to be measured is large. Sometimes the effect is great.
さらに、測定対象は金属板に限らず、後えば海
水であつてもよい。ただし、この場合相互インダ
クタンスの変化分は複素数になる。したがつて、
本発明は海水氷の厚さの推定にも適用できる。す
なわち、１次コイルに高周波電流を流し、２次コ
イルに誘起される電圧の位相角を検出することに
より、海氷の厚さを推定するものである。（詳し
くは、「海氷の厚さ推定方法」、特開昭58−223704
参照）
〔発明の効果〕
以上説明したように本発明によれば、被測定物
に対して近い第１の２次コイルと、被測定物に対
して第１の２次コイルより遠い第２の２次コイル
を１次コイルを挟んで対向配置し、１次コイルと
第１の２次コイルとの間隔を該１次コイルと第２
の２次コイルとの間隔よりも大きくするととも
に、第１の２次コイルの巻線数を第２の２次コイ
ルの巻線数よりも多くしたことにより、被測定物
である例えば、金属板が第１の２次コイルから離
れた位置にあつても、変位感度が小さくならず、
高精度の計測ができる。 Furthermore, the object to be measured is not limited to a metal plate, but may also be seawater. However, in this case, the amount of change in mutual inductance becomes a complex number. Therefore,
The present invention can also be applied to estimation of seawater ice thickness. That is, the thickness of sea ice is estimated by passing a high frequency current through the primary coil and detecting the phase angle of the voltage induced in the secondary coil. (For details, see ``Sea Ice Thickness Estimation Method,'' JP-A-58-223704.
(See) [Effects of the Invention] As explained above, according to the present invention, the first secondary coil is closer to the object to be measured, and the second secondary coil is farther from the object to be measured than the first secondary coil. The secondary coils are arranged opposite to each other with the primary coil in between, and the interval between the primary coil and the first secondary coil is set so that the distance between the primary coil and the second
By making the distance between the first secondary coil and the second secondary coil larger and the number of turns of the first secondary coil larger than the number of turns of the second secondary coil, the object to be measured, such as a metal plate, Even if the coil is located away from the first secondary coil, the displacement sensitivity does not become small;
Capable of high-precision measurement.
第１図は本発明に係る差動相互誘導型渦流計測
用センサの概略図、第２図は従来の差動相互誘導
型渦流計測用センサの概略図、第３図は相互イン
ダクタンス測定時における２次コイルの差動接続
図である。
Ｐ……１次コイル、Ｓ１……第１の２次コイ
ル、Ｓ２……第２の２次コイル。
Fig. 1 is a schematic diagram of a differential mutual induction type eddy current measurement sensor according to the present invention, Fig. 2 is a schematic diagram of a conventional differential mutual induction type eddy current measurement sensor, and Fig. 3 is a schematic diagram of a differential mutual induction type eddy current measurement sensor according to the present invention. It is a differential connection diagram of the next coil. P...Primary coil, S1...First secondary coil, S2...Second secondary coil.
Claims (1)
被測定物に対して第１の２次コイルより遠い第２
の２次コイルを１次コイルを挟んで対向配置し、
１次コイルと第１の２次コイルトの間隔を該１次
コイルと第２の２次コイルとの間隔よりも大きく
するとともに、第１の２次コイルの巻線数を第２
の２次コイルの巻線数よりも多くしたことを特徴
とする差動相互誘導型渦流計測用センサ。1 a first secondary coil close to the object to be measured;
The second secondary coil, which is further away from the first secondary coil with respect to the object to be measured,
The secondary coils are arranged opposite to each other with the primary coil in between,
The interval between the primary coil and the first secondary coil is made larger than the interval between the primary coil and the second secondary coil, and the number of turns of the first secondary coil is
A differential mutual induction type eddy current measurement sensor characterized in that the number of turns is greater than that of the secondary coil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27316184A JPS61151402A (en) | 1984-12-26 | 1984-12-26 | Differential mutual induction type eddy current measuring sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27316184A JPS61151402A (en) | 1984-12-26 | 1984-12-26 | Differential mutual induction type eddy current measuring sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61151402A JPS61151402A (en) | 1986-07-10 |
| JPH0523361B2 true JPH0523361B2 (en) | 1993-04-02 |
Family
ID=17523945
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27316184A Granted JPS61151402A (en) | 1984-12-26 | 1984-12-26 | Differential mutual induction type eddy current measuring sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61151402A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01118303U (en) * | 1988-01-29 | 1989-08-10 | ||
| US6570379B2 (en) * | 2000-08-24 | 2003-05-27 | Shell Oil Company | Method for inspecting an object of electrically conducting material |
| US6707296B2 (en) * | 2000-08-24 | 2004-03-16 | Shell Oil Company | Method for detecting cracks in electrically conducting material |
| US6593737B2 (en) * | 2000-08-24 | 2003-07-15 | Shell Oil Company | Method for measuring the wall thickness of an electrically conductive object |
| JP2003004407A (en) * | 2001-06-20 | 2003-01-08 | Sankyo Seiki Mfg Co Ltd | Displacement measuring device |
| JP5513821B2 (en) * | 2009-09-17 | 2014-06-04 | 株式会社荏原製作所 | Eddy current sensor, polishing apparatus, plating apparatus, polishing method, plating method |
| JP4975142B2 (en) * | 2010-06-17 | 2012-07-11 | トヨタ自動車株式会社 | Eddy current measuring sensor and eddy current measuring method |
| JP2017142200A (en) * | 2016-02-12 | 2017-08-17 | 株式会社東海理化電機製作所 | Position detector |
| CN117940769A (en) * | 2021-09-24 | 2024-04-26 | 三菱电机株式会社 | Orientation direction detecting device |
-
1984
- 1984-12-26 JP JP27316184A patent/JPS61151402A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61151402A (en) | 1986-07-10 |
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