JPS61155983A - Magnetic body detector - Google Patents
Magnetic body detectorInfo
- Publication number
- JPS61155983A JPS61155983A JP59277449A JP27744984A JPS61155983A JP S61155983 A JPS61155983 A JP S61155983A JP 59277449 A JP59277449 A JP 59277449A JP 27744984 A JP27744984 A JP 27744984A JP S61155983 A JPS61155983 A JP S61155983A
- Authority
- JP
- Japan
- Prior art keywords
- detection
- circuit
- coil
- oscillation
- temp
- 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
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
- G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
- G01V3/104—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils
- G01V3/105—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils forming directly coupled primary and secondary coils or loops
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Life Sciences & Earth Sciences (AREA)
- Electromagnetism (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
本発明は、磁性体を磁気的に検知する磁性体検知器に関
する。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a magnetic material detector that magnetically detects a magnetic material.
〈従来技術とその問題点〉
磁性体の検知器(センサ技術VO1,1,Nct 12
)として次のものがある。第5図に従来の検知器の一例
を示す。励起コイル1に発振器6を接続し、励起コイル
IK交流電流を流す。励起コイル1から出る磁場が励起
コイル1の近傍に配置された検知コイル2を貫くことK
より、検知コイル2iC誘導電圧が生ずる。検知器に磁
性体が近づくと磁場の分布が変化しそれKよって検知コ
イルに生ずる誘導電圧本変化する。この電圧変化を電圧
検出部5で検知することKよりて、磁性体の有無及び磁
性体と検知器の距離等を知ることができる。<Prior art and its problems> Magnetic material detector (sensor technology VO1, 1, Nct 12
) are as follows. FIG. 5 shows an example of a conventional detector. An oscillator 6 is connected to the excitation coil 1, and an alternating current is passed through the excitation coil IK. The magnetic field emitted from the excitation coil 1 penetrates the detection coil 2 placed near the excitation coil 1.
As a result, an induced voltage in the sensing coil 2iC is generated. When a magnetic body approaches the detector, the distribution of the magnetic field changes, thereby changing the induced voltage generated in the sensing coil. By detecting this voltage change with the voltage detection section 5, it is possible to know the presence or absence of the magnetic material, the distance between the magnetic material and the detector, etc.
ここで、磁性体の無い場合の検知コイ純誘導電圧をベー
ス電圧、そして、磁性体が検知器に近づいたときの検知
コイルの誘導電圧の変化分を検知感度と呼ぶことにする
。検知感度を上げるために励起コイルと検知コイルには
適当な容量のコンデンサーを付は電気的な共振点を揃え
、その共振周波数で発振させている。Here, the pure induced voltage of the sensing coil when there is no magnetic material is called the base voltage, and the change in the induced voltage of the sensing coil when the magnetic material approaches the detector is called the detection sensitivity. To increase detection sensitivity, capacitors of appropriate capacitance are attached to the excitation coil and detection coil to align the electrical resonance points and cause oscillation at that resonance frequency.
従来は、水晶振動子等温度に対して安定な発振子を使用
したため、周囲温度に対して発振周波数が非常に安定し
ていた。しかし、励起コイルや検知コイルの共振周波数
は温度によって変化する。Conventionally, an oscillator that is stable against temperature, such as a crystal resonator, was used, so the oscillation frequency was extremely stable against ambient temperature. However, the resonant frequencies of the excitation coil and detection coil change depending on the temperature.
このため発振周波数は励起コイルと検知コイルの共振点
からずれてしまい感度が変動する原因となっていた。For this reason, the oscillation frequency deviates from the resonance point of the excitation coil and the detection coil, causing sensitivity fluctuations.
これに対し、従来は検知コイル、励起コイルのLC共振
器に、温度補償用コンデンサーをつけて温度変化に対し
て共振周波数が変動しないような工夫をして固定周波数
で発振させた場合の検知感度を最大に保ってきた。しか
し、この調整のために素子の選択に大きな制約を受はコ
イルの設計を難しくしている。In contrast, in the past, the detection sensitivity was increased by attaching a temperature compensation capacitor to the LC resonator of the detection coil and excitation coil so that the resonant frequency did not fluctuate due to temperature changes and causing the LC resonator to oscillate at a fixed frequency. has been kept to a maximum. However, this adjustment places significant restrictions on element selection, making coil design difficult.
〈発明の目的〉
本発明は検知器の温度が変化しても常に最大検知感度が
保てるように自動的に温度補償する回路構成を持つセン
サーを提供することを目的とする。<Objective of the Invention> An object of the present invention is to provide a sensor having a circuit configuration that automatically compensates for temperature so that maximum detection sensitivity can always be maintained even if the temperature of the detector changes.
〈発明の構成〉
磁場励起コイルと磁場検知コイルとを備えた磁性体検知
器において、磁場励起用発振回路、検知回路のそれぞれ
に、コイル(L)とコンデンサ(C)を用い、そのLC
回路の共振周波数の温度変化が零でなく、かつ、磁場励
起用LC発振回路の発振周波数の温度変化と、検知用L
C回路での共振周波数の温度変化が同じであることを特
徴とする。<Structure of the Invention> In a magnetic material detector equipped with a magnetic field excitation coil and a magnetic field detection coil, a coil (L) and a capacitor (C) are used in each of the magnetic field excitation oscillation circuit and the detection circuit, and the LC
The temperature change in the resonant frequency of the circuit is not zero, and the temperature change in the oscillation frequency of the LC oscillation circuit for magnetic field excitation and the detection L
The C circuit is characterized in that the resonant frequency changes with temperature in the C circuit are the same.
〈本発明の作用・原理〉
本発明では交流磁場を発生する励磁コイルをLC発振器
に組み込むことにより、最小の電力で効率よく励磁電流
を流すように設計しである。さらに検知コイルは、コン
デンサーを並列に用い最大の電圧を発生するように構成
しである。<Operation/Principle of the Present Invention> The present invention is designed to efficiently flow an excitation current with minimum electric power by incorporating an excitation coil that generates an alternating magnetic field into an LC oscillator. Additionally, the sensing coil is configured to generate the maximum voltage using a capacitor in parallel.
上の構成の場合、励磁コイルを含む発振回路の共振周波
数は1発振回路につけたLとCの積によって定まり、そ
の温度変化は、LとCのそれぞれの温度変化によって規
定される。一方、検知コイルを含む電圧検知回路には、
共振用コンデンサに適当なものを選んであシ、共振周波
数とその温度変化が励起コイルを含む発振回路の共振周
波数とその温度変化に等しくなるように共振用コンデン
サーを選んである。このため、検知器の温度が変化して
も、たえず発振回路と検知回路の両方の共振周波数で動
作し、最大検知感度が得られるようになっている。In the case of the above configuration, the resonant frequency of the oscillation circuit including the excitation coil is determined by the product of L and C applied to one oscillation circuit, and its temperature change is defined by the temperature change of L and C, respectively. On the other hand, the voltage detection circuit including the detection coil has
An appropriate resonant capacitor is selected so that its resonant frequency and its temperature change are equal to the resonant frequency and its temperature change of the oscillation circuit including the excitation coil. Therefore, even if the temperature of the detector changes, both the oscillation circuit and the detection circuit continue to operate at the resonant frequency, providing maximum detection sensitivity.
この場合、従来のように臨席変化によって共振周波数が
全くずれ々くする必要はなくて、共振同波数の温度変化
が励起用のLC回路と検知&のLC回路で同一であれば
よいのである。In this case, there is no need for the resonant frequency to shift at all due to the presence change as in the conventional case, and it is sufficient that the temperature change at the same resonant wave number is the same in the excitation LC circuit and the detection & detection LC circuit.
〈実施例〉
本発明の実施例を示すブロック図を第1図に示す。励起
コイル1と検知コイル2には、コアに同じ巻き数のコイ
ルを巻き、適当な共振用コンデンサー3をつけたLC共
振器を用いた場合を示している。4は正帰還回路、5は
電圧検出部である。<Embodiment> A block diagram showing an embodiment of the present invention is shown in FIG. For the excitation coil 1 and the detection coil 2, a case is shown in which an LC resonator having the same number of turns wound around the core and an appropriate resonance capacitor 3 attached is used. 4 is a positive feedback circuit, and 5 is a voltage detection section.
第2図に発振回路の一例として、コルピッツ型発振器に
励起コイルを組み込んだ場合を示す。励起コイル1は、
正帰還回路と組み合わせてLC発振器のLとして用いて
いるため、発振周波数は、常に共振周波数と一致する。FIG. 2 shows an example of an oscillation circuit in which an excitation coil is incorporated into a Colpitts oscillator. The excitation coil 1 is
Since it is used as L of the LC oscillator in combination with a positive feedback circuit, the oscillation frequency always matches the resonant frequency.
なお、2は検知コイル、3け共振用コンデンサーである
。Note that 2 is a detection coil and a 3-piece resonance capacitor.
タンスCI、C2はトランジスタに接続する2個のコン
デンサの容量である。The capacitances CI and C2 are the capacitances of two capacitors connected to the transistors.
第2図では、トランジスタ7で帰還をかけているが、I
C等の適当なパワー素子でおきかえることもできる。In Fig. 2, feedback is applied by transistor 7, but I
It can also be replaced with a suitable power element such as C.
第3図に一例を示すように磁場励起用発振回路の発振周
波数(実線)と検知用回路の共振周波数(破線)け昇温
とともに低くなる。同じ新質のコアを使用し、かつ、適
当な温度係数のコンデンサを用いてあシ、変化率は、は
ぼ等しくなっている。As an example is shown in FIG. 3, the oscillation frequency of the magnetic field excitation oscillation circuit (solid line) and the resonance frequency of the detection circuit (broken line) decrease as the temperature rises. By using the same new core quality and using capacitors with appropriate temperature coefficients, the rates of change are approximately equal.
磁性体の検知レベルを従来と比較したものの一例を第4
図に示す。・、ムは、それぞれ従来型及び本発明のペー
ス電圧を示し101Δは、それぞれ同じ〈従来型、本発
明の一定距離に磁性体が近づいた場合の出力電圧を示す
。従って検知電圧は、破線と実線の電圧差である。従来
型は、ペース電圧の変化に伴い、検知電圧も変化してい
るが本発明は、ペース電圧、検知電圧と吃に温度に対し
ほぼ一定の値をとる。An example of a comparison of the detection level of magnetic substances with conventional methods is shown in Part 4.
As shown in the figure. . . , mu indicate the pace voltage of the conventional type and the present invention, respectively, and 101Δ indicates the output voltage when the magnetic body approaches a certain distance of the same conventional type and the present invention, respectively. Therefore, the detected voltage is the voltage difference between the broken line and the solid line. In the conventional type, the detection voltage changes as the pace voltage changes, but in the present invention, the pace voltage, the detection voltage, and the temperature each take a substantially constant value.
以上のように、本発明の検知器は温度変化に対し、はぼ
一定の検知電圧を示すような温度補償がなされている。As described above, the detector of the present invention is temperature compensated so that it exhibits a nearly constant detection voltage against temperature changes.
さらに、従来のように励磁用のLC共振器の外に発振器
をもつような回路構成に比べ、発振周波数に励起コイル
のLC共振点を合わせるといった面倒な初期調整がなく
なること、またシンプルな回路構成になるだめ、素子数
が減り信頼度が上がる一方でコストダウンにつながるこ
と等の副次的なメリットがあげられる。Furthermore, compared to conventional circuit configurations that have an oscillator outside the excitation LC resonator, the troublesome initial adjustment of matching the LC resonance point of the excitation coil to the oscillation frequency is eliminated, and the circuit configuration is simple. However, the number of elements is reduced and reliability is increased, while there are secondary benefits such as cost reduction.
〈発明の効果〉
本発明の構成をとることにより、温度変化に対して常に
最大検知感度をもつ周波数で動作させることができ、そ
れに伴いベース電圧、検知電圧を温度に対してf!J
?!一定に保つことができる。<Effects of the Invention> By employing the configuration of the present invention, it is possible to always operate at a frequency that has the maximum detection sensitivity against temperature changes, and accordingly, the base voltage and the detection voltage are adjusted to f! J
? ! can be kept constant.
また、従来の検知器に対し1回路構成がシンプルになり
、調整個所が減り5安価に製品化できる。In addition, compared to conventional detectors, the single circuit configuration is simpler, the number of adjustment points is reduced, and the product can be manufactured at a lower cost.
第1図は、本発明の実施例を示すブロック図である。
第2図は1本発明の回路構成の一例を示す図である。
第3図、第4図は、本発明の効果の一例を示す図である
。
第5図は、従来の実施例を示すブロック図でおる。図に
おいて、
1.・・・励起コイル、2・・・検知コイル、31.共
振用コンデンサー、4.・・・正帰還回路、5.・電圧
検出部、6.・・・発振器、7.・・トランジスタ。
閏11、弁Tニーし、31弓(霧
第 1 図
土谷 (
1: Nυヒコ4ル
2 ; &矢ロコイル
3 ; 只#用コンテ°゛ン“ワ′
7 : トランシ′°スタ
第 3 図
温度(0C)FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a diagram showing an example of the circuit configuration of the present invention. FIG. 3 and FIG. 4 are diagrams showing an example of the effects of the present invention. FIG. 5 is a block diagram showing a conventional embodiment. In the figure: 1. . . . Excitation coil, 2 . . . Detection coil, 31. Resonance capacitor, 4. ...Positive feedback circuit, 5.・Voltage detection section, 6. ...oscillator, 7. ...Transistor. Leap 11, Valve T knee, 31 Bow (Mist 1st Figure Tsuchiya (1: Nυhiko 4le 2; & Arrow Locoil 3; Container for only #) 7: Transistor Star 3rd figure Temperature (0C)
Claims (1)
器において、磁場励起用発振回路、検知回路のそれぞれ
にコイル(L)とコンデンサー(C)を用いそのLC回
路の共振周波数の温度変化が零でなく、かつ磁場励起用
LC発振回路の発振周波数の温度変化と、検知用LC回
路での共振周波数の温度変化が同一であることを特徴と
した磁性体検知器。In a magnetic detector equipped with a magnetic field excitation coil and a magnetic field detection coil, a coil (L) and a capacitor (C) are used in the magnetic field excitation oscillation circuit and the detection circuit, respectively, and the temperature change in the resonance frequency of the LC circuit is zero. What is claimed is: 1. A magnetic substance detector characterized in that a temperature change in the oscillation frequency of the magnetic field excitation LC oscillation circuit and a temperature change in the resonant frequency of the detection LC circuit are the same.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP59277449A JPS61155983A (en) | 1984-12-28 | 1984-12-28 | Magnetic body detector |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP59277449A JPS61155983A (en) | 1984-12-28 | 1984-12-28 | Magnetic body detector |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS61155983A true JPS61155983A (en) | 1986-07-15 |
Family
ID=17583728
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP59277449A Pending JPS61155983A (en) | 1984-12-28 | 1984-12-28 | Magnetic body detector |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS61155983A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009500615A (en) * | 2005-07-07 | 2009-01-08 | ツェットエフ フリードリヒスハーフェン アクチエンゲゼルシャフト | Automotive fittings |
-
1984
- 1984-12-28 JP JP59277449A patent/JPS61155983A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009500615A (en) * | 2005-07-07 | 2009-01-08 | ツェットエフ フリードリヒスハーフェン アクチエンゲゼルシャフト | Automotive fittings |
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