JPH074491Y2 - Eddy current type displacement sensor - Google Patents
Eddy current type displacement sensorInfo
- Publication number
- JPH074491Y2 JPH074491Y2 JP1988124726U JP12472688U JPH074491Y2 JP H074491 Y2 JPH074491 Y2 JP H074491Y2 JP 1988124726 U JP1988124726 U JP 1988124726U JP 12472688 U JP12472688 U JP 12472688U JP H074491 Y2 JPH074491 Y2 JP H074491Y2
- Authority
- JP
- Japan
- Prior art keywords
- bobbin
- sensor
- eddy current
- thermal expansion
- adhesive
- 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
Landscapes
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
Description
【考案の詳細な説明】 〔産業上の利用分野〕 本考案は渦電流型変位センサーに関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an eddy current displacement sensor.
渦電流効果を利用した渦電流型変位計は、第６図模式図
に示すように、センサー10と信号処理回路部20から構成
され、計測対象物体30とセンサー10との距離ｘを計測す
るために使用されるものであり、センサー10のコイルを
一定の周波数を持つ正弦波で励磁すると、計測対象物体
30に渦電流が発生し、その影響によりセンサー10のコイ
ルのインピーダンスが見かけ上変化し、それはセンサー
10と対象物体30の距離ｘの関数となり、そのインピーダ
ンス変化を信号処理回路部20で電圧に変換出力する。An eddy current type displacement meter utilizing the eddy current effect is composed of a sensor 10 and a signal processing circuit unit 20 as shown in the schematic diagram of FIG. 6, and is for measuring a distance x between an object 30 to be measured and the sensor 10. When the coil of the sensor 10 is excited by a sine wave with a constant frequency, the object to be measured is
An eddy current is generated in 30, and the effect causes an apparent change in the impedance of the coil of sensor 10.
It becomes a function of the distance x between the target object 30 and the target object 30, and the impedance change is converted into a voltage and output by the signal processing circuit unit 20.
しかしてセンサー10は、第７図縦断面図に示すように、
円筒状のボビン11′の外周に設けられたリング状溝12′
に、銅等の金属線を巻いて測定コイル13′を形成し、そ
れを固着するために外側に接着剤14′を塗付してある。
なおこのセンサー10の電気的等価回路は、第８図回路図
に示すように、測定コイル13′及び対象物体30により形
成されるインダクタンス17と、測定コイル13′の金属線
自身の固有抵抗18と、接着剤14′及びボビン11′で形成
される浮遊容量19で表わされる。Then, the sensor 10 is, as shown in FIG.
A ring-shaped groove 12 'provided on the outer periphery of a cylindrical bobbin 11'.
A measuring wire 13 'is formed by winding a metal wire such as copper, and an adhesive 14' is applied to the outside to fix the measuring coil 13 '.
The electrical equivalent circuit of this sensor 10 is, as shown in the circuit diagram of FIG. 8, an inductance 17 formed by the measuring coil 13 'and the target object 30, and a specific resistance 18 of the metal wire itself of the measuring coil 13'. , A floating capacitance 19 formed by the adhesive 14 'and the bobbin 11'.
このような渦電流型変位計による計測においては、第６
図のように対象物体30の近傍にセンサー10を設置し、セ
ンサー10よりその出力をリード線により信号処理回路部
20に導くが、センサー10を設置する場所は、機械の運転
等のため温度変化が発生する場合が多く、従つて周囲温
度変化によりセンサー10の温度が変化し、ボビン11′，
測定コイル13′の金属線及び接着剤14′が熱膨張により
大きくなる。In the measurement by such an eddy current type displacement meter,
As shown in the figure, the sensor 10 is installed near the target object 30, and the output from the sensor 10 is connected to the signal processing circuit section by the lead wire.
The temperature of the sensor 10 is often changed at the place where the sensor 10 is installed due to machine operation or the like. Therefore, the temperature of the sensor 10 is changed due to the ambient temperature change, and the bobbin 11 ′,
The metal wire of the measuring coil 13 'and the adhesive 14' become large due to thermal expansion.
ボビン11′，測定コイル13′の金属線及び接着剤14′が
熱膨張により大きくなると、コイル13′の幾何学的形状
が変化し、センサー10のインダクタンス17及び浮遊容量
19が変化することになり、そのためセンサー10と対象物
体30との距離ｘは変化していないのに、渦電流型変位計
よりの出力は変化しあたかも距離ｘが変化したような出
力信号変化となり、温度による影響のため精度よく距離
ｘを計測できないことになる。When the bobbin 11 ', the metal wire of the measuring coil 13' and the adhesive 14 'become large due to thermal expansion, the geometrical shape of the coil 13' changes, and the inductance 17 and stray capacitance of the sensor 10 are changed.
19 changes, so the distance x between the sensor 10 and the target object 30 does not change, but the output from the eddy current displacement meter changes and the output signal changes as if the distance x changed. , The distance x cannot be accurately measured due to the influence of temperature.
またボビン11′の線膨張率より接着剤14′の線膨張率が
大きい材料を使用するときには、第９図正面図に示すよ
うに、その線膨張率差によりボビン頂部11a′に過大な
応力が発生してそこに亀裂11b′が生じ、センサー10の
信頼性を低下させることになる。When a material having a linear expansion coefficient of the adhesive 14 'which is larger than that of the bobbin 11' is used, as shown in the front view of FIG. 9, an excessive stress is applied to the top 11a 'of the bobbin due to the difference in the linear expansion coefficient. The cracks 11b 'are generated there and the reliability of the sensor 10 is deteriorated.
本考案は、このような事情に鑑みて提案されたもので、
測定コイルの熱膨張によるインダクタンス及び浮遊容量
変化が小さく、そのため渦電流型変位計の出力変化が小
さくなつて変位計測精度を向上することができ、かつボ
ビン頂部の亀裂発生がなくセンサーの信頼性向上がはか
れる渦電流型変位センサーを提供することを目的とす
る。The present invention has been proposed in view of such circumstances,
Inductance and stray capacitance change due to thermal expansion of the measuring coil is small, so the output change of the eddy current type displacement gauge is small and the displacement measurement accuracy can be improved, and there is no cracking on the top of the bobbin and sensor reliability is improved. It is an object of the present invention to provide an eddy current type displacement sensor that can be covered.
そのために本考案は、外周にリング状溝を有する円筒状
で熱膨張率が小さいセラミックス製ボビンと、上記溝内
に巻装された測定コイルと、上記溝内の測定コイル外側
に塗布され熱膨張率が上記セラミックスと同等の無機系
接着剤とを具えたことを特徴とする。To this end, the present invention provides a cylindrical bobbin having a ring-shaped groove on the outer periphery and a small coefficient of thermal expansion, a measuring coil wound in the groove, and a thermal expansion applied to the outside of the measuring coil in the groove. It is characterized in that it has an inorganic adhesive whose rate is equivalent to that of the above ceramics.
本考案渦電流型変位センサーにおいては、熱膨張率がほ
とんど同じでかつ小さいセラミックス及び無機系接着剤
をボビン及び接着剤に採用したことにより、それらの熱
膨張による形状変化が小さくなり、それにより測定コイ
ルの半径及び巻線間隔の変化も小さくなって、センサー
の温度変化によるインダクタンス及び浮遊容量変化が小
さくなる。そのため温度による変位計よりの出力変化が
小さくなり精度よく計測できる。またボビン，接着剤の
熱膨張率が同じなのでボビン頂部の亀裂はなくなり信頼
性の高いセンサーが得られる。In the eddy current type displacement sensor of the present invention, by adopting ceramics and inorganic adhesives which have almost the same thermal expansion coefficient and small to the bobbin and the adhesive, the change in shape due to the thermal expansion becomes small, which results in the measurement. The changes in the radius of the coil and the winding interval are also small, and the changes in the inductance and stray capacitance due to the temperature changes of the sensor are small. Therefore, the output change from the displacement meter due to temperature is small, and accurate measurement is possible. In addition, since the bobbins and adhesives have the same coefficient of thermal expansion, cracks at the top of the bobbins are eliminated and a highly reliable sensor can be obtained.
本考案渦電流型変位センサーの一実施例を図面について
説明すると、第１図はその縦断面図、第２図は同上のボ
ビンの斜視図、第３図は同上の測定コイルの縦断面図、
第４図はボビン材料の熱膨張係数の説明図、第５図は接
着剤の熱膨張係数の説明図である。An embodiment of the eddy current type displacement sensor of the present invention will be described with reference to the drawings. FIG. 1 is a vertical sectional view of the same, FIG. 2 is a perspective view of a bobbin of the same, and FIG. 3 is a vertical sectional view of a measuring coil of the same.
FIG. 4 is an explanatory view of the thermal expansion coefficient of the bobbin material, and FIG. 5 is an explanatory view of the thermal expansion coefficient of the adhesive.
第１図及び第２図において、センサー10は、セラミック
ス製の円筒状のボビン11の外周に設けられたリング状溝
12に、銅等の金属を材料とする被覆金属線を巻き測定コ
イル13を形成している。In FIGS. 1 and 2, the sensor 10 is a ring-shaped groove provided on the outer circumference of a cylindrical bobbin 11 made of ceramics.
A coated metal wire made of a metal such as copper is wound around 12 to form a measuring coil 13.
この測定コイル13をボビン11のリング状溝12に固着する
ために、測定コイル13外側に無機系接着剤14を塗付して
おり、またボビン11からはリード線15が導出されるとと
もに、ボビン11下部は種々の場所への設置が容易なよう
にねじ付きアダプター16に接着剤を用いて取りつけてあ
る。In order to fix the measurement coil 13 to the ring-shaped groove 12 of the bobbin 11, an inorganic adhesive 14 is applied to the outside of the measurement coil 13, and the lead wire 15 is led out from the bobbin 11 and 11 The lower part is attached to the threaded adapter 16 with an adhesive so that it can be easily installed in various places.
しかしてボビン11のセラミックス材と接着剤14の無機系
接着剤とは、線膨張率がほぼ同程度の材料を選定してあ
る。すなわち第４図に示すように、セラミックスの線膨
張率は、鉄，アルミニウム等の金属に比較するとかなり
小さいが、セラミックスの種類により種々異なり、また
第５図に示すように、無機系接着剤の線膨張率は、エポ
キシ系接着剤に比較すると約1/10程度と小さいが、材質
により種々異なるので、これらセラミックス材と無機系
接着剤の線膨張率のほぼ等しいものを選定組合わせて採
用している。Therefore, as the ceramic material of the bobbin 11 and the inorganic adhesive of the adhesive 14, materials having linear expansion coefficients of about the same are selected. That is, as shown in FIG. 4, the coefficient of linear expansion of ceramics is considerably smaller than that of metals such as iron and aluminum, but it varies depending on the type of ceramics, and as shown in FIG. The coefficient of linear expansion is about 1/10 that of an epoxy adhesive, which is small, but it differs depending on the material.Therefore, select and combine those ceramic materials and inorganic adhesives that have approximately the same coefficient of linear expansion. ing.
そのためセンサー10の周囲温度が上昇してもボビン11,
接着剤14の熱による膨張はわずかであり、第３図に示す
測定コイル13の半径R1,R2及びコイル巻線間の間隔ｄの
変化は、接着剤14にエポキシ系接着剤を用い、ボビン11
材料に鉄等を使用したときに比べ小さいものとなる。従
ってボビン11,接着剤14及び測定コイル13の形状変化が
小さくなることによって、センサーの温度変化によるイ
ンダクタンス及び浮遊容量の変化が小さくなる。Therefore, even if the ambient temperature of the sensor 10 rises, the bobbin 11,
The expansion of the adhesive 14 due to heat is slight, and the radii R 1 , R 2 of the measuring coil 13 and the change in the interval d between the coil windings shown in FIG. 3 are changed by using an epoxy adhesive as the adhesive 14. Bobbin 11
It is smaller than when iron or the like is used as the material. Therefore, the change in shape of the bobbin 11, the adhesive 14, and the measuring coil 13 is reduced, and thus the change in inductance and stray capacitance due to the temperature change of the sensor is reduced.
またボビン11と接着剤14の線膨張率がほぼ同程度である
ので、接着剤14の熱膨張によりボビン11の頂部11aに過
大な応力が加わることはなく、亀裂の発生はない。Moreover, since the linear expansion coefficients of the bobbin 11 and the adhesive 14 are approximately the same, excessive stress is not applied to the top 11a of the bobbin 11 due to the thermal expansion of the adhesive 14, and cracks do not occur.
かくしてこのような装置によれば、熱膨張による測定コ
イル13の変形が小さいので、測定コイル13の熱膨張によ
るインダクタンス及び浮遊容量変化が小さくなり、その
ため渦電流型変位計よりの出力変化が小さくなり、対象
物体との距離を精度よく計測できる。またボビン頂部11
aに過大な応力が加わらないので、そこに亀裂の発生は
なくセンサー10の信頼性向上がはかれる。Thus, according to such a device, since the deformation of the measuring coil 13 due to thermal expansion is small, the change in inductance and stray capacitance due to thermal expansion of the measuring coil 13 is small, and therefore the output change from the eddy current displacement gauge is small. , The distance to the target object can be accurately measured. Also bobbin top 11
Since an excessive stress is not applied to a, no crack is generated there and the reliability of the sensor 10 can be improved.
要するに本考案によれば、外周にリング状溝を有する円
筒状で熱膨張率が小さいセラミックス製ボビンと、上記
溝内に巻装された測定コイルと、上記溝内の測定コイル
外側に塗布され熱膨張率が上記セラミックスと同等の無
機系接着剤とを具えたことにより、測定コイルの熱膨張
によるインダクタンス及び浮遊容量変化が小さく、その
ため渦電流型変位計の出力変化が小さくなつて変位計測
精度を向上することができ、かつボビン頂部の亀裂発生
がなくセンサーの信頼性向上がはかれる渦電流型変位セ
ンサーを得るから、本考案は産業上極めて有益なもので
ある。In short, according to the present invention, a cylindrical ceramic bobbin having a ring-shaped groove on the outer periphery and a small coefficient of thermal expansion, a measuring coil wound in the groove, and a thermal coating applied to the outside of the measuring coil in the groove. By using an inorganic adhesive with a coefficient of expansion equivalent to that of the above ceramics, changes in inductance and stray capacitance due to thermal expansion of the measurement coil are small, and therefore changes in output of the eddy current displacement gauge are small and displacement measurement accuracy is improved. INDUSTRIAL APPLICABILITY The present invention is extremely useful in industry because it provides an eddy current type displacement sensor that can be improved and that the reliability of the sensor can be improved without the occurrence of cracks at the top of the bobbin.
第１図は本考案渦電流型変位センサーの一実施例の縦断
面図、第２図は同上のボビンの斜視図、第３図は同上の
測定コイルの縦断面図、第４図はボビン材料の熱膨張係
数の説明図、第５図は接着剤の熱膨張係数の説明図であ
る。 第６図は公知の渦電流型変位計の模式図、第７図は従来
のセンサーの縦断面図、第８図は同上の等価回路図、第
９図は同上のボビンの正面図である。 10……センサー、11……ボビン、11a……ボビン頂部、1
2……リング状溝、13……測定コイル、14……接着剤、1
5……リード線、16……アダプター、17……インダクタ
ンス、18……固有抵抗、19……浮遊容量、20……信号処
理回路部、30……計測対象物体。FIG. 1 is a longitudinal sectional view of an embodiment of the eddy current displacement sensor of the present invention, FIG. 2 is a perspective view of the bobbin of the same, FIG. 3 is a longitudinal sectional view of a measuring coil of the same, and FIG. 4 is a bobbin material. 5 is an explanatory view of the coefficient of thermal expansion of FIG. FIG. 6 is a schematic view of a known eddy current displacement meter, FIG. 7 is a longitudinal sectional view of a conventional sensor, FIG. 8 is an equivalent circuit diagram of the same, and FIG. 9 is a front view of a bobbin of the same. 10 …… Sensor, 11 …… Bobbin, 11a …… Bobbin top, 1
2 …… Ring groove, 13 …… Measuring coil, 14 …… Adhesive, 1
5: Lead wire, 16 ... Adapter, 17 ... Inductance, 18 ... Specific resistance, 19 ... Stray capacitance, 20 ... Signal processing circuit section, 30 ... Object to be measured.
Claims (1)
率が小さいセラミックス製ボビンと、上記溝内に巻装さ
れた測定コイルと、上記溝内の測定コイル外側に塗布さ
れ熱膨張率が上記セラミックスと同等の無機系接着剤と
を具えたことを特徴とする渦電流型変位センサー。1. A ceramic bobbin having a ring-shaped groove on the outer periphery and a small coefficient of thermal expansion, a measuring coil wound in the groove, and a coefficient of thermal expansion applied to the outside of the measuring coil in the groove. Comprises an inorganic adhesive equivalent to the above ceramics, which is an eddy current displacement sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1988124726U JPH074491Y2 (en) | 1988-09-26 | 1988-09-26 | Eddy current type displacement sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1988124726U JPH074491Y2 (en) | 1988-09-26 | 1988-09-26 | Eddy current type displacement sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0247515U JPH0247515U (en) | 1990-03-30 |
| JPH074491Y2 true JPH074491Y2 (en) | 1995-02-01 |
Family
ID=31374708
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1988124726U Expired - Lifetime JPH074491Y2 (en) | 1988-09-26 | 1988-09-26 | Eddy current type displacement sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH074491Y2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3696277B2 (en) * | 1995-01-18 | 2005-09-14 | Ｎｔｎ株式会社 | Magnetic bearing |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6037868U (en) * | 1983-08-23 | 1985-03-15 | カルソニックカンセイ株式会社 | rotation sensor |
-
1988
- 1988-09-26 JP JP1988124726U patent/JPH074491Y2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0247515U (en) | 1990-03-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3936734A (en) | Method for contactless measurement of conductivity and/or temperature on metals by means of eddy currents | |
| JP2698749B2 (en) | Combined coating thickness gauge for non-ferrous coatings on iron substrates and non-conductive coatings on conductive substrates | |
| US6853183B2 (en) | Non-contact position sensor having helicoidal conductor forming a measuring surface covering a measuring object | |
| US3371272A (en) | Electromagnetic sensing probe structure and system for gaging proximity of metals and the like utilizing a linear variable differential transformer | |
| US5297439A (en) | Magnetoelastic stress sensor | |
| US4918418A (en) | Inductive coil structure with electrical return path | |
| US4805466A (en) | Device for the contactless indirect electrical measurement of the torque at a shaft | |
| US4899598A (en) | Apparatus for measuring torque applied to a shaft | |
| US5191286A (en) | Method and probe for non-destructive measurement of the thickness of thin layers and coatings | |
| KR930000932A (en) | Method and device for checking adhesion and thickness of double tube sharing area | |
| Wang et al. | A compact and high-performance eddy-current sensor based on meander-spiral coil | |
| US6639401B2 (en) | Contactless, transformer-based measurement of the resistivity of materials | |
| US7576532B2 (en) | Motion transducer for motion related to the direction of the axis of an eddy-current displacement sensor | |
| JPH074491Y2 (en) | Eddy current type displacement sensor | |
| JPS5818603B2 (en) | Fushiyokusonmodokenshiyutsusouchi | |
| US4909088A (en) | Apparatus for mounting a sensor | |
| US3452273A (en) | Non-contact displacement transducer with feedback controlled vibration amplitude and a probe having a sensing means disposed transversely of the direction of vibration | |
| US4738131A (en) | Guarded ring tensioned thickness standard | |
| US4858818A (en) | Method of bonding a magnetostrictive sheet to a shaft | |
| JPS63273001A (en) | Displacement measuring instrument | |
| JP3065114B2 (en) | Method and apparatus for balancing a displacement transducer measurement sequence by eddy current measurement | |
| JPS625603Y2 (en) | ||
| JP3110327B2 (en) | Differential transformer | |
| JPS609697Y2 (en) | Continuous induction liquid level gauge | |
| JPS5818602B2 (en) | Corrosion wear detection method |